HK1116360A - Integrated modular lighting unit - Google Patents

Description

Integrated modular lighting unit

Technical Field

[0001] The invention belongs to the field of lighting systems, and particularly relates to an integrated modular light emitting device lighting unit, wherein the modular lighting unit can adjust and control light color and correlated color temperature.

Background

[0002] With respect to general lighting, the original edison base incandescent lamp and all its derivatives have remained relatively unchanged to date. Although many of the evolving technologies have explored long-life, high-efficiency, and more compatible light sources over decades, the basic form of the lighting device structure remains relatively stable.

[0003] Other lamp types are commonly seen in the lighting industry. For example, a fluorescent lamp may provide an elongated cylindrical light source. In the case of high intensity discharge lamps, the shape is often similar to that of a conventional incandescent lamp having a glass bulb and a metal screw-top socket that mates with a respective electrical socket. These forms of lighting are ubiquitous and spread throughout the general lighting field representing most industries worldwide.

[0004] These general lamp types are well suited to support the task of the various general light emitting structures or methods present in each glass blister. In particular, these lamp types provide a protective mechanical environment, preventing the escape of internal gases and/or the entry of external gases, which could contaminate the internal components of the lamp, thus destroying its function. In addition, these forms can provide a stable thermal environment that contains internal gases and maintains the temperature at a level that contributes to light output. They may also provide a reliable and standardized form factor for providing electrical contact at the base or end of the lamp, e.g. they may match an industry standard socket form. Edison screw socket is the most common form of interface because it provides a mechanical connection that supports the entire bulb while providing reliable and redundant metallic electrical contacts at multiple points along the screw shell. Further, these general lamp types can provide a reflector shape suitable for the lighting device and a convenient optical shape for light emission of the optical element. The oldest and simplest lamp types provide a substantially spherical light emission pattern from a filament within a glass envelope. As lamp types have evolved over time, reflector lamps have emerged in the form of bulbs which, for example, contain a reflector mounted inside or outside the bulb to produce a "beam" of light. Finally, these general lamp types can provide a convenient standard amount of light that is often suitable for lighting tasks. Over a decade, lamps remain relatively unchanged, with some standard sizes and wattages often being consistent even among different manufacturers. Examples include the commonly used 60 watt incandescent a-type lamps, the 40 watt T12 fluorescent lamps, and the 250 watt high pressure sodium lamps, each of which were developed to suit a particular type of lighting fixture, application, and/or market.

[0005] With the advent of competitive Light Emitting Diode (LED) technology that surpasses the performance of almost all incandescent lamps in terms of electrical efficiency and average lifetime, industry forecasts has suggested that LEDs may have a performance of 150 lumens per watt, and even 200 lumens per watt. These numbers easily exceed that of conventional white light sources currently producing less than 100 lumens/watt of light. LEDs may provide a strong economic benefit since the sole maximum cost to the owner of any given lamp is the electrical consumption over the life of the lamp.

[0006] A key problem in achieving widespread marketability of LEDs is that their production is significantly more variable and does not exhibit a standardized shape or structure that contributes to general lighting applications. For example, in the initial light output of a group of LED chips produced by the same apparatus, grown on the same wafer, the luminous flux output on the same wafer has a variation as large as about 3: 1. This fact leads to a grading strategy commonly used in the industry whereby LEDs are tested individually, classified into luminous flux output categories representing about 30% intervals. Also, forward voltage, dominant wavelength, and beam spread may be other factors considered in the classification process.

[0007] Structurally, LEDs are often packaged in a single piece package, depending on the needs of the indicator market. Many of which are designed to be soldered to circuit boards and are designed to use electronic manufacturing equipment and methods. The optical elements associated with these packages are often damaged to provide a specific or desired beam pattern, resulting in an optical efficiency of less than about 60%. Many of these LED packages rely on a metal frame that acts as a cooling heat sink for thermal regulation, but some recent LED packages have begun to use thermal contact pads in intimate contact with the substrate for efficient heat transfer.

[0008] A variety of lighting devices have been designed over the years to use light emitting diodes. In particular, european patent No.1,416,219 discloses an LED lighting device with a connector and a driving circuit. The connector is connected to a pluggable and removable card-type LED illumination source that includes a plurality of LEDs mounted on one surface of a substrate. The illumination drive circuit is electrically connected to the card-type LED illumination source by means of the connector. The card type LED illumination source preferably includes a metal substrate with a plurality of LEDs mounted on one side of the metal substrate. The back surface of the metal substrate is not mounted with LEDs and is in thermal contact with a portion of the lighting device. A feeder terminal electrically connected to the connector is provided on a surface of the metal substrate on which the LED is provided, so that the LED mounted on the card-type member can be electrically energized.

[0009] This european patent discloses several features of a stand-alone lighting device; however, no means is provided to enable color control, intensity control, thermal control or any other control of the lighting device beyond the linear electrical driving of the LEDs. Furthermore, such a stand-alone lighting device cannot interact or communicate with other lighting devices and therefore functions autonomously.

[0010] U.S. patent No.6,617,795 discloses a multi-chip led package having a support, at least two led chips disposed on the support, at least one sensor disposed on the support for reporting quantitative colorimetric information about the led light output to a controller, and signal processing circuitry disposed on the support including analog-to-digital converter logic for converting the analog signal output generated by the sensor to a digital signal output. The problem of preventing overheating of the LED is addressed and the use of a temperature sensor is suggested to provide a way to monitor such parameters. However, such devices do not include active means to remove heat from the device or means to thermally condition within the LED package. Furthermore, while such packaging allows connection to some type of external power source, it does not provide control or limitation of the power delivered to the LEDs, and thus the thermal and control of such devices is limited.

[0011] U.S. patent No.6,462,669 discloses a modular warning signal light system. The warning signal light system includes at least one support member having at least one module receiving opening for removably receiving a support mating member of another module. Each module includes at least one visible side having at least one light emitting diode light source mated thereto. The LED light source, the module and the support are all independently in electrical communication with the controller. The controller is configured to selectively activate the at least one support, the at least one module, the at least one light emitting diode light source, and any combination thereof to generate the at least one warning light signal. However, such systems do not include any means for thermal management and do not mention any data collection in operation to control various performances related to the functionality of the light system, and thus the thermal and control of such systems is limited.

[0012] U.S. patent No.6,331,063 discloses an LED lighting device formed in such a manner that a plurality of LED chips are three-dimensionally disposed on an MID (molded interconnect device) substrate in the shape of a rectangular plate. Three LED chips are provided on the bottom surface of each recess provided longitudinally and transversely on one surface of the MID substrate. The LED chip is selected from at least two types different in emission color from each other, and it is also disclosed that it is preferable to use three types of LEDs, i.e., red, blue, and green. In this manner, optional light distribution characteristics can be obtained depending on the structure of the substrate and the LEDs thereon. In this manner, different colors, such as white and daylight colors of incandescent lamps and fluorescent lamps, can be realized by mixing the luminescent colors of the respective LED chips. However, no mention is made of a separate modular lighting unit designed to interact with other modular lighting units to generate light, nor is a modular design for the lighting unit disclosed.

[0013] Further, U.S. patent No.6,208,073 discloses an intelligent light emitting diode light cluster and system. The intelligent light cluster and system includes a Central Processing Unit (CPU) and a plurality of LED light cluster strings, each light cluster string including serially connected LED light clusters. Each LED light cluster includes an LED driving circuit and a plurality of LEDs, wherein a CPU receives an externally input image signal, and then a desired control signal and image data are sent to the LED light cluster string through appropriate processing. The control signals are used to switch the LEDs in the light cluster to produce the desired image and associated color change. Subsequently, the control signal and the image data are transferred to the next LED light cluster through the LED driving circuit. In this way, the control signal and image data are gradually transferred from the first cluster to the last cluster, and the entire image with color variations can be displayed by the LED clusters in the system. However, thermal regulation or operational feedback of individual LED clusters is not mentioned, and thus thermal and control of such systems is limited.

[0014] U.S. patent No.6,441,558 discloses a lighting device light control system including a controller system connected to a power platform. The controller is configured to provide a control signal to the power supply to maintain the DC current signal at a desired level to achieve a desired light output. Also disclosed is the use of temperature and light sensors to provide feedback about the light emitting device to enable the controller to maintain a desired luminous flux output for each LED. A complete lighting device system is disclosed, however no mention is made of the modular units that integrate and form the lighting device system. Furthermore, although such systems are intended to form complete systems, no method or means for thermal management is disclosed and, therefore, such systems encounter thermal regulation problems.

[0015] U.S. Pat. No.5,783,909 discloses a system for controlling the light intensity of light emitting diodes. In addition to a power source capable of providing a switched electrical supply to the LED, the invention includes a sensor for measuring the intensity of the LED light. The switched power supply uses a pulsed strategy to modulate the output to the LED to maintain the desired light intensity. However, such systems do not include means for dissipating heat from the LEDs, or any optics or any modular lighting device for color mixing, collimation or redirection. Thus, in addition to creating a substantially uniform illumination problem, such systems also encounter thermal problems.

[0016] U.S. patent No.6,741,351 discloses a lighting device having means for maintaining a desired color balance from arrays of red, green, and blue LEDs. The photodiode intercepts a sample of the light emitted from the LED. A method of testing the luminous flux output of each different color is disclosed, using a pulsing method that selectively turns LEDs on and off, thereby causing the light sensor to measure each LED individually. However, nothing is disclosed about any conceptual aspects of any thermal management, heat removal, or lighting unit modularity used in larger lighting systems. Such systems therefore suffer from thermal regulation problems.

[0017] Clearly, LED-based light sources have not yet evolved into compatible, user-friendly modular devices for general lighting. The prior art discloses attempts to address some of the difficulties associated with using light emitting devices in lighting applications, such as controlling intensity and chromaticity and removing heat from the LEDs. However, no integrated solution that meets the general lighting requirements while having the advantages of light emitting devices is currently available. Therefore, there is a need for a new integrated modular light emitting device lighting unit that can be used as a single unit or combined with other modular units, maintaining a given intensity and chromaticity, while taking advantage of the efficacy and lifetime of the light emitting device, thereby providing designers with flexibility to design lighting devices based on light emitting devices.

[0018] The purpose of the foregoing background information is to enable the applicants to understand information that may be relevant to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.

Disclosure of Invention

[0019] It is an object of the present invention to provide an integrated modular lighting unit. According to an aspect of the present invention, there is provided an integrated lighting module comprising: one or more light-emitting elements for producing illumination; an optical system optically connected to the one or more light-emitting elements and for processing the illumination; a feedback system for collecting information representative of an operating characteristic of the one or more light-emitting elements, the feedback system generating one or more signals representative of the information; a thermal management system in thermal contact with the one or more light-emitting elements, the thermal management system to conduct heat away from the one or more light-emitting elements; a drive and control system for receiving the one or more signals from the feedback system, the drive and control system regulating input power, generating control signals and sending control signals to the one or more light-emitting elements, the control signals generated based on predetermined control parameters and the one or more signals.

[0020] According to another aspect of the invention, there is provided a networked lighting system comprising: two or more integrated lighting modules, each module comprising: one or more light-emitting elements for producing illumination; an optical system optically connected to the one or more light-emitting elements and for processing the illumination; a feedback system for collecting information representative of an operating characteristic of the one or more light-emitting elements, the feedback system generating one or more signals representative of the information; a thermal management system in thermal contact with the one or more light-emitting elements, the thermal management system to conduct heat away from the one or more light-emitting elements; a drive and control system for receiving the one or more signals from the feedback system, the drive and control system regulating input power, generating control signals and sending control signals to the one or more light-emitting elements, the control signals generated based on predetermined control parameters and the one or more signals; and a communication system operatively connected to the drive and control system, the communication system being communicable between the two or more integrated lighting modules.

Drawings

[0021] Fig. 1 is a diagram of the components of an integrated lighting module of one embodiment of the present invention.

[0022] Fig. 2 is a diagram of the functional blocks of the drive and control system illustrating the demarcation between the drive and control of the integrated lighting module of one embodiment of the present invention.

[0023] Fig. 3A to 3G illustrate the structure of a driver sub-module of the driving and control system of the embodiment of the present invention.

[0024] Fig. 4 is a cross-sectional view of a clover-leaf Compound Parabolic Concentrator (CPC) optical element of an optical system according to one embodiment of the present invention.

[0025] Figure 5 is a cross-sectional view of a parabolic reflector optical element of an optical system of one embodiment of the present invention.

[0026] Figure 6 is a cross-sectional view of a segmented parabolic reflector optical component of an optical system according to one embodiment of the present invention.

[0027] Fig. 7 is a cross-sectional view of an optical element of an optical system including a parabolic mirror and a long-pass filter structure according to one embodiment of the present invention.

[0028] FIG. 8 illustrates a lighting unit of one embodiment of the present invention, including a multi-module QFP (Quad Flat Package, "Quad Flat Pack") package incorporating a heat pipe.

[0029] FIG. 9 illustrates an integrated modular lighting unit torch lamp of another embodiment of the present invention.

[0030] Fig. 10 illustrates an integrated modular lighting unit lighting fixture according to another embodiment of the present invention.

[0031] Fig. 11 illustrates a lighting unit of another embodiment of the invention, comprising a sub-module of a plurality of light-emitting elements.

[0032] Fig. 12 illustrates a lighting unit of another embodiment of the present invention, having components in a stacked configuration.

[0033] Fig. 13 illustrates a lighting module of one embodiment of the present invention.

[0034] Fig. 14 illustrates a lighting module of another embodiment of the present invention.

[0035] Fig. 15 illustrates the lighting module of fig. 14, wherein the optical system has been separated from the remaining lighting modules.

[0036] Fig. 16 is a cross-sectional view of a lighting module integrated within a housing according to one embodiment of the present invention.

[0037] Fig. 17 illustrates a lighting module of one embodiment of the present invention.

[0038] Fig. 18 illustrates an optical system of an illumination module of one embodiment of the present invention.

[0039] Figure 19 illustrates a thermal management system according to one embodiment of the present invention.

Detailed Description

Definition of

[0040] The term "light-emitting element" is used to define any device that emits radiation in any region or combination of regions of the electromagnetic spectrum (e.g., the visible region, infrared and/or ultraviolet region) when activated, for example, by applying a potential difference across it or passing a current through it. Thus, the light-emitting element may have monochromatic, quasi-monochromatic, polychromatic or broadband spectral emission characteristics. Examples of light-emitting elements include semiconductor, organic or polymer/polymer light-emitting diodes, optically pumped phosphor-coated light-emitting diodes, optically pumped nano-crystal light-emitting diodes or any other similar light-emitting device as would be readily understood by a worker skilled in the art. Furthermore, the term light-emitting element is used to define the specific device that emits the radiation, such as the LED die, and is also used to define the combination of the specific device that emits the radiation and the housing or package in which the specific device is placed.

[0041] The term "about" as used herein refers to a deviation from normal of +/-10%. It is to be understood that such a deviation is always included in any given value provided herein, whether or not it is specifically referred to.

[0042] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0043] The present invention provides an integrated stand-alone lighting module that can be used alone or in combination with other modules to produce white light or any other color within the color gamut available for the light-emitting elements. Each module includes one or more light emitting elements, a drive and control system, a feedback system, a thermal management system, an optical system, and optionally a communication system capable of communicating between the modules and/or other control systems. Depending on the structure, the lighting module may operate autonomously or its function may be determined based on both internal and externally received signals, a separate externally received signal or a separate internal signal.

[0044] Fig. 1 illustrates a diagram of a lighting module and its components. The lighting module 10 includes a light source 50 that includes one or more light-emitting elements for producing illumination. The external power source 40 provides power to the lighting module 10, wherein the power so provided is regulated by the drive and control system 20. Such power conditioning may include, for example, converting supplied external power to a desired input power level determined based on characteristics of the light-emitting elements within the module. Furthermore, for power conversion, the drive and control system provides means for controlling the transmission of control signals to the light-emitting elements, thereby controlling their activation. The drive and control system may receive input data from the lighting module 10, for example from the feedback system 30, and may receive external input data from other lighting modules or other control devices. The optional communication port 100 may provide the drive and control system with the ability to input and output signals to and from the module, respectively.

[0045] The feedback system 30 within the module 10 may include one or more forms of detectors or other similar devices. For example, the light sensor 70 and/or the thermal sensor 80 may be integrated into the feedback system. The light sensor 70 may, for example, detect and provide information to the drive and control system regarding the luminous flux and chromaticity of the illumination produced by the light-emitting elements and ambient daylight readings. This form of information enables the drive and control system to vary the activation of the light-emitting elements within the module to produce the desired illumination. The thermal sensor 80 may detect, for example, the temperature of the substrate on which the light emitting elements are mounted, the temperature of one or each of the light emitting elements, and the temperature within the lighting module itself. Such temperature information may be communicated to a drive and control system, for example, to enable varying activation of the light-emitting elements to reduce thermal damage to the light-emitting elements due to overheating, thereby improving their lifetime.

[0046] The thermal management system 90 provides a system for transferring heat generated by the light source 50 to a heat sink or other heat dissipation device. The thermal management system includes a predetermined thermal pathway in intimate thermal contact with the light-emitting element and providing for heat transfer away from the light-emitting element. Optionally, the thermal management system may also provide a means for transferring heat away from the drive and control system.

[0047] The optical system 60 receives the illumination generated by the light source 50 and provides a means for effectively optically controlling such illumination. The optical system may, for example, provide a means for collecting and/or collimating the luminous flux 110 emitted by the light source 50 and may provide color mixing of the emissions of the plurality of light-emitting elements. The optical system may also control the spatial distribution of light emitted from the illumination module. In addition, the optical system may provide a means for directing a portion of the illumination toward the light sensor 70 to generate a feedback signal representative of the illumination characteristics generated by the illumination module.

[0048] In one embodiment, the lighting module's drive and control system 20 may operate independently of other external lighting modules and external control systems.

[0049] In another embodiment, the drive and control system 20 may receive input data from other lighting modules or external control systems via the optional communication port 100, wherein such data may include, for example, status signals, lighting signals, feedback information, and operational commands. The drive and control system 20 may likewise communicate externally received data or internally collected or generated data to other lighting modules or external control systems. This information transfer can be accomplished through an optional communication port 100 connected to the drive and control system.

Light source

[0050] The light source comprises one or more light-emitting elements that can be selected to provide a predetermined light color. The number, type and color of the light emitting elements within the light source may provide a way to obtain high luminous efficiency, high Color Rendering Index (CRI) and large color gamut. Furthermore, the light emitting elements may be positioned relative to the optical system to achieve optimized color mixing and collimation efficiency. Light-emitting elements can be made using organic materials, such as OLEDs or PLEDs, or inorganic materials, such as semiconductor LEDs.

The light emitting elements may be primary light emitting elements that emit light including blue, green, red, or any other color. The light-emitting element optionally may be a secondary light-emitting element that converts the emission of the primary source into one or more monochromatic wavelengths, polychromatic wavelengths, or broadband emissions, such as in the case of blue or UV pumped phosphor-coated white LEDs, photonic regenerative semiconductor LEDs, or nanocrystal-coated LEDs. Further, combinations of primary and/or secondary light emitting elements may be used. As will be readily understood by a person skilled in the art, the one or more light emitting elements may for example be mounted on a PCB (printed circuit board), an MCPCB (metal core PCB), a metallized ceramic substrate or a dielectric coated metal substrate supporting the tracks and connection pads. The light emitting element can be in an unpackaged form, such as a mandrel form, or can be a packaged part, such as an LED package, or can be packaged with other components, including a drive circuit, a feedback circuit, an optical system, and a control circuit.

[0051] In one embodiment, for example, an array of light-emitting elements whose spectral output is centered around wavelengths corresponding to the colors red, green, and blue may be selected. Optionally, other spectral output light emitting elements may also be incorporated into the array, for example light emitting elements emitting in the red, green, blue and amber wavelength regions may be configured as light sources, or optionally may include one or more light emitting elements emitting in the cyan wavelength region. The choice of the light emitting elements of the light source is directly related to the desired color gamut and/or the desired maximum luminous flux and color rendering index produced by the lighting module.

[0052] In another embodiment of the invention, where multiple light-emitting elements are combined in an additional manner, any combination of monochromatic, polychromatic and/or broadband sources is possible. The combination of light emitting elements includes a combination of red, green, and blue (RGB) light emitting elements, a combination of red, green, blue, and amber (RGBA) light emitting elements, and a combination of the RGB and RGBA and white light emitting elements. It is possible that the primary and secondary light emitting elements are combined in additional ways. Furthermore, combinations of monochromatic sources with polychromatic and broadband sources are also possible, such as light emitting elements producing light of the colors RGB and white, GB (green and blue) and white, a (amber) and white, RA (red and amber) and white, RGBA and white. The number, type, and color of the plurality of light-emitting elements can be selected depending on the lighting application and the lighting requirements to meet the desired luminous efficiency and/or CRI.

[0053] In one embodiment, the light emitting elements may also be selected based on similar temperature dependence, for example phosphor-coated white LEDs, green LEDs and blue LEDs based on common InGaN semiconductor technology. The selection criteria of the light emitting elements for such a light source may easily provide temperature compensation in the control of these light emitting elements.

[0054] In one embodiment, a plurality of light emitting elements may be electrically connected in various structures. For example, the light emitting elements may be connected in a series or parallel configuration or a combination thereof. In one embodiment of the invention, two or more light-emitting elements are connected in series in a linear string, wherein the string may for example comprise light-emitting elements of the same color class, or various colors or combinations of color classes. In such an embodiment of the invention, all light emitting elements in the string are electrically connected such that they are powered as a group by the driving and control system of the lighting module.

[0055] In another embodiment of the present invention, light emitting elements are combined in series into linear string pairs, wherein a string may comprise light emitting elements of a combination of color classes of the same color, e.g., blue, wherein the dominant wavelength of light emitting elements of one of the linear string pairs is equal to or greater than a predetermined wavelength and the dominant wavelength of light emitting elements of the other string of the string pairs is equal to or less than the predetermined wavelength. Thus, by adjusting the relative drive current applied to a given color string to each string, the effective dominant wavelength of a given color of the lighting module can be dynamically adjusted. In this manner, the plurality of lighting modules forming the lighting network may exhibit the same color gamut and produce the same chromaticity of light in response to commands throughout the lighting network.

[0056] In another embodiment of the invention, the light emitting elements are electrically connected such that each light emitting element can be managed and controlled individually by the drive and control system of the lighting module. For example, a string of light emitting elements may be wired such that some light emitting elements may be partially or fully bypassed, such that each light emitting element may be individually controlled independently of each other.

Drive and control system

[0057] The integrated drive and control system may receive power from an external power source, condition the power, and distribute the power to the light emitting elements. The drive and control system may provide power control in response to signals received from the feedback system, such as light and thermal feedback signals, to maintain color balance and light output within predetermined limits. The performance of the drive and control system can be configured to be highly efficient and respond smoothly to maintain a stable load on the external power source while being able to quickly switch activation of the light emitting elements and changes in power settings without producing excessive current spikes or visible fluctuations in light output. Furthermore, the driving and control system is flexible to accommodate different types of light emitting elements in a lighting module having different forward voltage and/or current requirements, without the need for sorting as in the prior art.

[0058] The drive and control system provides a way of controlling the supply of electrical power to the plurality of light-emitting elements. In one embodiment of the invention, the drive and control system uses digital switching to achieve this form of control. The power supplied to the light-emitting elements can be digitally switched using techniques such as Pulse Width Modulation (PWM), Pulse Code Modulation (PCM), or any other similar method known in the art. In this manner, control of the illumination produced by each light emitting element or string of light emitting elements can be controlled so that a desired illumination effect, such as dimming, flashing, or other visible or non-visible effect, such as an optical communication signal, can be produced.

[0059] In one embodiment of the invention, the series-connected light-emitting elements are powered by one external power supply, wherein all light-emitting elements in the series can be controlled as a unit by the drive and control system.

[0060] The drive and control system may be configured to activate the light emitting elements at a predetermined frequency, wherein such predetermined frequency may be an optimized frequency. In one embodiment, the switching frequency may be selected in a manner that satisfies one or more of the following characteristics, such as a switching frequency high enough to make visual flicker imperceptible, e.g., greater than about 60Hz, audible resonance of the power components outside the range of human hearing, e.g., greater than about 16kHz, and thermal stress of the light emitting element may be minimized by ensuring that the selected switching period is substantially less than, e.g., the thermal time constant of the LED die, which is typically on the order of 10 milliseconds, such that the desired switching frequency is greater than about 1 kHz.

[0061] In another embodiment of the invention, the junction temperature of a light-emitting element, such as an LED die, is monitored and the maximum slope of the drive current change is limited to limit the maximum change in junction temperature over time, thereby limiting the thermal stress of the light-emitting element that can lead to premature device failure due to, for example, wire debonding or accelerated device degradation due to nonradiative dislocation growth.

[0062] In one embodiment of the invention, the driving and control system uses a microcontroller or Field Programmable Gate Array (FPGA) which can receive signals from a feedback system regarding the operating conditions of the lighting module, such as light feedback, temperature feedback, and also external control signals to generate digital switching signals to be transmitted to each light emitting element or string of light emitting elements. In this way, the intensity level of the light-emitting element can be determined based on the received information, so that the desired color and illumination intensity can be generated.

[0063] Further, in one embodiment, each light emitting element or string of light emitting elements may be connected with an efficient switching converter to provide a constant current output from a common supply rail. Which may be configured to provide a constant DC current or a constant peak current in case the light emitting elements are to be digitally switched at different duty cycles. In this way, strings that impose different voltage drops on the strings can be properly driven using the same voltage supply, since each string will only be provided with the voltage needed to drive it at a predetermined current level. In one embodiment of the invention, the buck converter associated with a particular light emitting element or string of light emitting elements may be configured to regulate the power supplied according to the voltage drop applied across the light emitting element or string of light emitting elements and the particular voltage supplied by the common power supply rail. As will be readily appreciated by those skilled in the art, any form of switched mode DC-DC converter may be used, such as a flyback, buck, boost or buck-boost converter.

[0064] In another embodiment of the present invention, when the lighting module is dimmed, the driving current supplied to the light emitting element is reduced. For example, the drive current may be 100% maximum within 50% to 100% of the maximum luminous flux output, and the drive current may be 50% maximum for luminous flux outputs less than 50% maximum. A particular advantage of this configuration is that the duty cycle of the PWM or PCM drive signal is increased for low light levels. This configuration may alleviate timing requirements such as sampling of the light flux output of the light sensor or the forward voltage of the voltage sensor. Another advantage is that drive current harmonics due to the smaller duty cycle binary pulse wave can be reduced, thereby mitigating potential problems with power line harmonics and radio frequency emissions.

[0065] In one embodiment of the invention, the drive and control system may be integrated with other electronic components on the same Printed Circuit Board (PCB) that also includes the light emitting elements to provide a smaller form factor design, for example as shown in fig. 8 or 9. Alternatively, the drive and control system may be located on a separate dedicated PCB adjacent to the PCB holding the other electronic components and light emitting elements, the circuit boards being electrically and mechanically interconnected to achieve different form factors, for example as shown in fig. 12. A particular advantage of using such a separate dedicated PCB is that the drive and control system can be thermally isolated from the light emitting elements that generate heat, thereby reducing device temperature and increasing system reliability and ambient operating temperature.

[0066] In one embodiment, the drive and control system may be separated into two separate functional blocks as shown in fig. 2, where the driver module 1000 receives input from the interface of the control module 1005 and the light emitting elements, e.g., red LED 1010, green LED1015, and blue LED 1020, to maintain the drive level based on the input. The multi-color LEDs 1010, 1015, and 1020, the driver module 1005, the control module 1000, and the sensor module 1025 are configured as shown in fig. 2. The sensor module forms part of the feedback system 30 shown in fig. 1. The operating characteristics of the LEDs 1010, 1015, 1020 can be monitored by the sensor module 1025 to detect their light output, operating temperature, or other information, and thus the sensor module can include one or more light sensors, one or more temperature sensors, and any other desired sensors depending on the desired information to be collected.

[0067] In one embodiment, some of the light emitted by LEDs 1010, 1015, 1020 may be sent directly onto the light sensors in sensor module 1025 without passing through optical element 1030. In an alternative embodiment, the light signal representative of the characteristics of the light produced by the LED may be measured indirectly within the optical element 1030, as the light first passes through the optical element. Thus, in one embodiment of a system using multiple color LEDs, such as red, green, and blue, the signal detected by the light sensor may represent a mixture of light emitted from all of the LEDs.

[0068] In the embodiment shown in fig. 2, the control module 1000 may send a signal or signals to the driver module 1005 to drive the red, green, and blue LEDs 1010, 1015, 1020 to a desired level such that the combined output from these LEDs is maintained at a desired intensity and chromaticity setpoint, where the signal or signals may be based on one or more feedback signals from the sensor module 1025, for example, which may be stored internally in the control module, or which may be adjusted based on user input through a user interface, for example. In one embodiment, the control module may act autonomously to maintain the white light output emitted from the lighting module such that this light output is substantially at the black body location. By actively monitoring the mixed light output produced by the lighting module using a feedback system, the control module can evaluate and deliver control signals to the driver module to maintain the desired light output.

[0069] In one embodiment, the control module may adjust the CCT of the white output light in response to input from the user interface. In this case, the user does not have any direct control of the output of the light-emitting elements, since the control module performs appropriate calculations to actively adjust the light-emitting element drive current level, so that the color balance at the desired white point can be maintained. This process can greatly simplify the CCT adjustment by the user and allow for basic user interfaces, such as wall dimmers, to be present.

[0070] In another embodiment, the user may increase or decrease the total light output intensity of the lighting module while allowing the control module to maintain a suitable intensity ratio between the different colors of the light-emitting elements, thus maintaining substantially the same white point even when dimming. In another embodiment, the control module may be configured to maintain any point or group of points within the color gamut of the light-emitting elements of the light source. In another embodiment, a sophisticated user interface may provide the user with the ability to select any color in the color gamut, wherein the control module may maintain such selected color through active data received from the feedback system.

[0071] Fig. 3A-3G illustrate how the driver module regulates power to a light emitting element, such as an LED. As is known, LEDs are constant current devices, in one embodiment shown in fig. 3A, a driver module 2000, specifically a driver 2005 or 2010, sends a drive signal to an LED or LED string 2015 or 2020 and receives a return signal back therefrom, allowing closed loop current control of the LED. In one embodiment, the drive and return signals are drive and return currents supplied to the LEDs. Within the driver, the current level supplied to the LED may be monitored to ensure that a fixed current level through the LED is maintained for a given control input of the control module, regardless of forward voltage variations caused by temperature, aging, or other LED degradation effects. In one embodiment, the driver includes a current sense resistor to monitor the drive current. In one embodiment, as shown in FIG. 3A, one driver receives one control input and drives one LED or a string of LEDs, and multiple drivers for multiple LEDs or strings of LEDs. Such a driver module structure may for example allow one driver to be connected with LEDs of one color, so that one control input can set all LEDs of one color to the same level without affecting LEDs or LED strings of any other color. The driver module structure shown in fig. 3A can remain substantially the same regardless of the forward voltage requirement differences between different LED strings. Alternatively, as shown in fig. 3B, one driver having multiple outputs may be used to drive multiple LEDs or strings of LEDs based on multiple control inputs.

[0072] Fig. 3C-3G illustrate alternative configurations for information transfer between a driver and the LEDs or LED strings it controls, where these configurations enable closed loop current control. In fig. 3C, the driver may send a drive signal to the LED and receive an associated return signal from the LED, as well as receive a sense signal from the LED. The sense signal may indicate, for example, a voltage of one or more LEDs in the string, where the sense signal may be used to monitor the current level. In an alternative embodiment shown in fig. 3D, the return path from the LED to the driver may be eliminated by grounding the LED. In another embodiment shown in fig. 3E, the sense signal may be eliminated when the current sensing means is integrated in the driver. Fig. 3F illustrates an embodiment in which the drive signal can be eliminated by connecting the LED directly to the input power supply, however this configuration requires a return signal for the driver to maintain the current of the LED at a desired level using internal current sensing and limiting. In another embodiment shown in fig. 3G, the return signal and the sense signal may be input into the driver, for example, without current sensing within the driver.

[0073] In one embodiment, the control module may send digital signals to the driver module, wherein the driver module is configured to switch the drive signals to turn on and off the light emitting elements in response to signals received from the control module, wherein such switching may be performed using Pulse Width Modulation (PWM), Pulse Code Modulation (PCM), or other digital switching protocols, wherein the on-times of the light emitting elements may be varied. Since the driver module maintains a constant current through the light emitting elements when they are on, the peak current remains the same when the average current or average power through the light emitting elements changes. Therefore, the intensity of the output light is proportional to the on-time or duty cycle of the switching signal. This dimming method may provide a way to minimize wavelength shift. Since the peak wavelength of the light-emitting element may be strongly affected by the junction temperature, a thermal management system associated with the lighting module may be configured to prevent the junction temperature from rising excessively even during times when the light-emitting element is driven above ordinary current levels. Large variations in peak current, even for the same average power or junction temperature, can cause significant wavelength shifts. Thus, maintaining the same peak current while varying the average current can help ensure that the peak wavelength shift is reduced over the entire dimming range, thereby improving the ability of the drive and control system to maintain a given chromaticity.

[0074] In another embodiment, the control module may send digital signals to the driver module, wherein the driver module is adapted to convert these digital signals into analog drive signals that are transmitted to the light emitting elements, wherein such conversion may be performed by a digital-to-analog converter.

[0075] In one embodiment, the digital signal transmitted to the light emitting elements is transmitted at a desired frequency to eliminate visible flicker in the resulting illumination and to ensure a desired level of accuracy at low duty cycles, which is required to maintain control of output intensity and chromaticity. In another embodiment of such a system, the control module may communicate more than one control input to each driver module, where the secondary signal may be used to adjust the peak current level, and the driver modules send the secondary signal to the light emitting elements, thereby providing a way to improve accuracy at low dimming levels.

[0076] In one embodiment of the invention, the electronic components of the driver module and the control module are mounted on a common circuit board, such as a polyimide or polyester laminate. In another embodiment, the electronic components of the driver module and the control module are mounted on separate single or multi-layer circuit boards that are electrically and mechanically interconnected by one or more flexible layers. Circuit boards for the electronic components of the driver module and the control module or these structures of these circuit boards may be configured within the lighting module to provide a small form factor that may be preferred and/or to facilitate dissipation of heat generated by the electronic components of the driver module and the control module.

[0077] In one embodiment of the present invention, the drive and control system 20 receives input signals from and responds to external devices through the communication port 100, which may include, for example, occupancy sensors, timers, daylight sensors, infrared communication sensors, optical communication sensors, wireless communication modules, building management systems, lighting network routers and bridges, data communication network routers and bridges, personal computers, and user interfaces. Responses to these received input signals may include prescribed lighting control sequences, on/off and dimming and control and/or color changes, occupancy sensor responses, load shedding, daylight harvesting, emergency lighting responses, status and error reports, and system and/or component life information reports.

[0078] In another embodiment of the present invention, the maximum drive current supplied to the light emitting element is initially less than the maximum current specified by the manufacturer. Then, as the light emitting element lifetime (which can be tens of thousands of hours) changes, the maximum drive current slowly increases, compensating for device aging and the resulting lamp lumen depreciation, until the maximum drive current equals the manufacturer-calibrated drive current at the end of the estimated lifetime of the light emitting element.

[0079] In one embodiment of the invention, since the lighting module comprises a thermal management system, the drive and control system may be configured to operate the light-emitting elements at a maximum current exceeding the manufacturer's rating, e.g. the light-emitting elements may be overdriven to increase the luminous flux output of the lighting module, if desired. The thermal management system provides a way to efficiently transfer heat away from the light emitting element, thereby providing a way to overdrive the light emitting element without degrading the life or operating characteristics of the light emitting element for thermal reasons.

Feedback system

[0080] The lighting module further comprises a feedback system for collecting and transmitting operating characteristics of the lighting module to the drive and control system, whereby the operating characteristics can be changed to comply with predetermined standards. The operating characteristics may include lighting or luminescent characteristics, thermal characteristics, and/or other characteristics as desired. The feedback system within the illumination module may include one or more forms of detectors or other feedback-type devices. For example, a light sensor and/or a thermal sensor may be integrated into the feedback system. The light sensor may for example detect and provide information to the drive and control system about the radiant flux and chromaticity of the light-emitting element in addition to ambient daylight readings. This information forms the ability for the drive and control system to alter the activation of the light-emitting elements within the lighting module to produce the desired illumination. This form of feedback may, for example, enable the lighting module to maintain a desired lighting level and color, and may also compensate for ambient light conditions. The feedback system may be configured to provide the drive and control system with sufficient speed and stability of response so that the observer cannot visually detect a change in light level or color. In one embodiment, the feedback system may operate at a sampling frequency greater than or equal to about 250 Hz.

[0081] Feedback may also be provided by thermal sensors that detect, for example, the temperature of the substrate or circuit board on which the light-emitting elements are mounted, the temperature of one or more light-emitting elements, and the temperature within the lighting module itself. This information can be transmitted, for example, to a drive and control system, so that the activation of the light-emitting element can be changed to prevent thermal damage to the light-emitting element due to overheating, thereby increasing its lifetime. Furthermore, by monitoring the temperature, the operation of the lighting module can be controlled, enabling temperature insensitive operation, such that the desired illumination level and color are maintained within predetermined limits, regardless of the temperature, which may be the ambient temperature or the temperature measured within the lighting module.

[0082] In one embodiment of the invention, the thermal sensor is configured to monitor the temperature of one or more light sensors. In this way, variations in the light detection characteristics of the one or more light sensors due to temperature variations can be compensated for by the drive and control system. Such light sensor temperature dependency compensation may provide a way for the lighting module to generate and maintain desired lighting characteristics in an efficient and effective manner.

[0083] The feedback system may include one or more sensors with the required circuitry, with the collected information then being transmitted to the drive and control system. In one embodiment, one or more light sensors are arranged in a geometric shape to optimize reception of sufficient illumination for proper operation of the light sensors. Furthermore, one or more light sensors may be connected with suitable circuitry to condition and/or amplify the signals generated by the light sensors, if desired. Circuitry coupled to one or more photosensors may also provide a means for providing one or both of signal gain control and variation of the integration time constant.

[0084] In an embodiment, and in particular with regard to the collection of optical properties of the light generated by the light source, the light emitting elements forming the light source are combined into two or more light clusters of one or more light emitting elements, wherein the light clusters are configured such that a portion of the light emitted by each light cluster is directly incident on a central axis, wherein each point along the central axis is equidistant from each light cluster. The light emitting elements within each cluster are typically placed close to each other with respect to the distance between each cluster. Thus, the path length of light incident on each point along the central axis is approximately equal for all light emitting elements. One or more photosensors are also configured with a central axis associated therewith such that the central axis of the optical cluster coincides with the central axis of the photosensor. In this manner, substantially equal optical path lengths are provided from each cluster to the photosensor, and it can be ensured that substantially the same portion of light emitted from each cluster is incident on the photosensor.

[0085] In one embodiment of the invention, the feedback system includes a plurality of filtered light sensors with associated color filters, such as silicon photodiodes with dyed plastic filters, to measure the chromaticity and intensity of the illumination produced by the illumination module. Thin-film Interference Filters and Polymer Optical Interference Filters based on giant Optical systems (GBO) can be used, as described, for example, in R.Strharsky and J.Wheatley, "Polymer Optical Interference Filters", Optics & Photonics New, 11.2002, pages 34-40, and also planar dielectric waveguide gratings, as described, for example, in R.Magnus and S.Wang, 1992, "New Principles for Filters" applied Physics Letters 61 (9): 1002-1024 and S.Peng and G.M.Morris, 1996, "Experimental disruption of organic analytes in Diffraction from two-Dimensional gradients", Optics Letters 21 (8): 549-. Each color filter may, for example, exhibit spectral bandpass characteristics that limit the response of the light sensor to a predetermined range of visible wavelengths, such as red, green, and blue. In another embodiment, the temperature of the filtered light sensor is monitored so that possible temperature-dependent changes in the spectral absorption characteristics of the filter can be estimated (as is known in thin-film interference filters). This thermal monitoring of the light sensor can compensate for temperature dependence. Suitable circuitry may also be incorporated into the optical sensor, if desired, to filter out any unwanted noise and also to provide amplification of the optical sensor signal.

[0086] In one embodiment of the invention, one light sensor is used to monitor the contribution of each light-emitting element individually to the total light output of the lighting module. In such an embodiment, a query sequence may be used to collect the individual illumination contributions of each light-emitting element by, for example, activating each light-emitting element individually in succession.

[0087] In another embodiment of the invention, a plurality of light sensors are used to monitor one light emitting element or group of light emitting elements.

[0088] In one embodiment of the invention, the light emitting element, when in an inactive state, can be used to measure the intensity and chromaticity of light incident thereon, thereby providing another means for illumination detection.

[0089] In another embodiment, the light sensor may include a linear array of light detectors that function as a spectroradiometer, enabling a more complete representation of the illumination. Such a light sensor may provide a way for the drive and control system to control the light emitting elements more accurately, as it provides intensity and chromaticity information.

[0090] In one embodiment, the temperature sensor is a thermistor, thermocouple, semiconductor diode or transistor with a known temperature dependence profile, so that a temperature feedback signal can be collected. In addition, temperature feedback regarding the operation of the lighting module may be derived from the forward voltage of one or more light-emitting elements or other known parameters that vary with temperature, such as the peak wavelength of the light-emitting element.

[0091] In one embodiment of the invention, the feedback system includes a proportional-integral-derivative (PID) controller for receiving the sensor input and providing a feedback signal to the drive and control system in a manner that maintains a constant luminous flux output and chromaticity and minimizes visually perceptible undershoots or overshoots of the luminous flux output and chromaticity in response to changes in the feedback signal.

[0092] In another embodiment of the present invention, the feedback System includes a trainable neural network, as disclosed in U.S. patent application publication No.2005/0062446, "Control System for and illumination Device Incorporating diffraction Light Sources" to linearize the feedback sensor signal prior to input into the PID controller. In such an embodiment, the feedback system comprises a computing device for receiving information from one or more sensors and determining the control parameters based on a multivariate function having a hyperplane solution defining a representation of constant light intensity and chromaticity. Under these conditions, the computing device may substantially linearize the information from the one or more sensors to determine a plurality of control parameters from the input information communicated to the drive and control system. The drive and control system may then determine the control signals to be sent to the light-emitting elements to control the resulting illumination.

Thermal management system

[0093] The lighting module further comprises a thermal management system for removing heat generated by the light-emitting elements. The thermal management system includes a predetermined thermal pathway in intimate thermal contact with the light-emitting element and providing for heat transfer away from the light-emitting element. The thermal channels have a low thermal resistance along the transfer channels and contact between the channels and the light emitting elements.

Passive cooling

[0094] In one embodiment of the invention, a thermal management system includes one or more heat pipes. The heat pipe has a condenser end and an evaporator end, wherein the condenser end may be connected with a heat sink or other removal or heat dissipation means, thereby enabling heat transfer to an external medium of the lighting module. The evaporator end is in thermal contact with the light emitting element. The light emitting element can be in direct physical contact with the evaporator end of the heat pipe or optionally mounted on a thermally conductive substrate, such as a Metal Core Printed Circuit Board (MCPCB) or a thermally conductive substrate having a conductive metal track applied thereon, wherein the substrate is in direct contact with the evaporator end of the heat pipe. The working fluid associated with the heat pipe, where the working fluid transfers heat from the evaporator end to the condenser end of the heat pipe, may be selected from a variety of fluids, including water and other suitable liquids as will be readily understood. Furthermore, one or more heat pipes may be designed with a specific shape, length and working fluid for the desired lighting module application.

[0095] In one embodiment, one or more heat sinks are thermally coupled to one or more heat pipes along its length.

[0096] FIG. 19 illustrates an embodiment of a thermal management system in which a heat pipe 1028 is thermally coupled to a heat sink 1029 that includes a plurality of fins oriented at an angle relative to the length of the heat pipe. The angle of connection between the fins and the heat pipe may provide a way to improve air movement through the heat sink relative to fins mounted perpendicular to the longitudinal direction of the heat pipe.

[0097] In one embodiment, a thermally conductive material such as thermal grease, solder, or thermally conductive epoxy may be used to minimize the thermal resistance at the contact location between the evaporator end of the heat pipe and the substrate. In addition, the evaporator end of the heat pipe may be shaped, polished, or machined to increase the contact area between the heat pipe and the substrate, thereby increasing the thermal conductivity therebetween. In addition, the substrate on which the light emitting element is mounted may be composed of a thin, highly thermally conductive material, such as Chemical Vapor Deposition (CVD) diamond, aluminum nitride ceramic, beryllium oxide ceramic, aluminum oxide ceramic, copper and polyimide, silicon, or silicon carbide. The connection of the light emitting element to the substrate substantially maximizes thermal conductivity therebetween. In such an embodiment, the evaporator of the heat pipe may be integrated into a substrate, package, or package on which the light emitting element is mounted.

[0098] In another embodiment of the invention, a thermal management system includes a thermosiphon device. Thermosiphon devices use an evaporator/condenser similar to the heat pipes described above to transfer heat away from the light emitting elements, but where the evaporator and condenser are connected by a continuous loop for fluid and vapor flow. In such an embodiment, the evaporator of the thermosiphon device may be integrated into the substrate on which the light emitting elements are mounted.

Active cooling

[0099] In one embodiment of the invention, the thermal management system comprises a Peltier (Peltier) effect thermoelectric cooling device or a thermal tunnel cooling device, such as described in U.S. Pat. No.6,876,123, which may be connected to or integrated into a substrate on which the light emitting elements are mounted. Thermoelectric devices are solid state devices, e.g., electrically biased, capable of transferring heat from a light emitting element into a thermal channel that may be defined by a heat pipe or thermosiphon device. In such embodiments, the heat pipe or thermosiphon device may be thermally coupled to the hot side of the thermoelectric device or thermal tunnel device.

[00100] In another embodiment, a thermal management system includes, for example, the systems described in A.Shakouri and J.E.Bowers, 1997, "heterogeneous Integrated thermal Coolers," Applied Physics Letters 71 (9): the thermionic device described in 1234-1236, which may be attached to or integrated into a substrate on which the light emitting elements are mounted. In a thermionic device, application of an electrical bias may provide a means for heat to flow away from a surface, such as a substrate.

[00101] In another embodiment, the thermal management system comprises a fluid cooling system, such as water or cooling oil, pumped through a heat exchanger that may be connected to or integrated into the substrate on which the light emitting elements are mounted. The fluid may act as a thermal pathway, transferring heat to another heat exchanger, and then to an external medium, such as ambient air. Alternatively, a mechanical or microfluidic pump may be used to pump fluid on any or all surfaces of the light-emitting element.

[00102] In one embodiment of the invention, the external medium to which heat is transferred by the thermal management system is a fluid that is easy to use for the lighting module. For example, in some configurations, an air conditioning system or water system may be proximate to the lighting module, and thus the thermal management system may be configured to transfer heat to an external system as an option to ambient air.

[00103] In another embodiment, the thermal management system includes a fan or other mechanical device for moving air to enhance heat transfer and dissipation.

Optical system

[00104] The optical system provides means for efficient light extraction and efficient light processing of the emission of the light source. The optical system may, for example, provide a means of extracting and collecting radiation, collimating the emission, and mixing the spectral content of the emissions from the plurality of light-emitting elements. The optical system may also control the spatial distribution of light emitted from the illumination module. In addition, the optical system may provide a means of directing a portion of the emission towards the light sensor, and may also block ambient light from the light sensor to produce feedback regarding the output lighting characteristics of the lighting module.

[00105] The optical system may be designed to provide any one or more of the following characteristics, including optimized collection efficiency of the illumination emitted by the light source, minimal loss of the optical system, beam collimation with small residual divergence or a nearly matching Lambertian beam shape, optimized color mixing within short optical path lengths, and a geometrically controllable luminous distribution without unwanted spatial light intensity or chromaticity variations.

[00106] Optical systems may use various optical elements to produce the desired light intensity and chromaticity distributions. The optical element may comprise one or more refractive elements such as glass or plastic lenses, Compound Parabolic Concentrators (CPCs) or advanced modifications thereof such as modified dielectric total internal reflection optics, Fresnel lenses, GRIN lenses and microlens arrays. The optical elements may also include reflective and diffractive elements, including holographic diffusers and GBO-based mirrors.

[00107] In one embodiment, the lighting module may comprise a set of sub-modules. In this configuration, the optical system may be divided into a primary optical system that collects and processes the light emitting element emissions of the sub-modules and a secondary optical system that processes the output of each sub-module, thereby further shaping the output of the illumination module. Optionally, the secondary optical system may not be needed if the primary optical system provides the required processing of the emitted light flux. The provision of primary and secondary optical elements enables multiple processing stages of the illumination produced by the light-emitting elements of the illumination module to produce a desired illumination pattern. In one embodiment, the primary optical system is configured to perform light extraction and collimation and the secondary optical system is configured to perform light mixing. It will be readily appreciated that the primary and secondary optical systems may perform any desired processing of the light produced by the light source.

[00108] In one embodiment, RGB or RGBA or white light emitting elements or a combination of white and color light emitting elements are tightly packed and encapsulated in an encapsulating material that enhances light extraction. An optical element such as a dome lens to enhance light extraction can be placed adjacent the light emitting element. Reflective optical elements such as tapered hollow light tubes can collimate and mix the light emissions. It should be understood that the optical element may take on different cross-sectional shapes, such as parabolic or a collection of straight segments adjusted. Optionally, a final optical element such as a glass convex lens, Fresnel lens or more complex lens may help shape the beam output of the sub-module. A secondary optical element, such as a holographic diffuser, may be placed over the sub-modules to alter the luminous distribution of the individual sub-modules or the combination of sub-modules.

[00109] In one embodiment of the invention, a Dielectric Total Internal Reflection Concentrator (DTIRC), such as a CPC optical element, may be used to collect the emission of multiple light-emitting elements. As an example, a square array of four light-emitting elements may form a light source for an illumination module or sub-module, and the optical system may be segmented CPCs configured in a cloverleaf pattern to achieve the desired collection efficiency. Fig. 4 illustrates a cross-section of a segmented CPC optical element 140 near two light emitting elements 142. It will be readily appreciated that the cross-sectional shape of the concentrator is not limited to parabolic but may be in the form of, for example, a hyperbola, an ellipse, a horn or a junction of a plurality of line segments, each of which is designed to meet the desired optical objectives.

[00110] In one set of embodiments of the invention, the optical system comprises a structure having a plurality of partially reflective surfaces for redirecting, color mixing and, if desired, collimating the emission of a plurality of light emitting elements, such as an RGBA structure of light emitting elements. Fig. 5 illustrates a cross-sectional view of a two-dimensional arrangement of light emitting elements with a parabolic reflector 150 placed proximate to the light emitting elements 152. Fig. 6 illustrates a sectional view of a segmented parabolic reflector including three segments 154, 156 and 158 positioned proximate to the light emitting element 152, again in a two-dimensional arrangement. Fig. 7 illustrates a microlens array 162 and a dichroic reflector/filter assembly 160 that can collimate the emission of a light emitting element 164. The reflective surfaces shown in fig. 7 are flat, however they may be of any desired shape, for example the reflective surfaces may optionally be parabolic or elliptical. These reflective surfaces may be selectively transmissive, e.g. they may be transmissive for illumination entering behind the reflector, but reflective for illumination emitted by the facing light-emitting elements.

[00111] In one embodiment, the optical elements of the optical system may be cup-shaped or half-cup-shaped, for example. This form of structure can be envisioned by rotating the two-dimensional cross-sectional views shown in fig. 5, 6 or 7 about axes parallel and proximate to the location of the light-emitting elements. For example, for a cup-shaped optical element, a rotation of 360 ° about a defined axis, and for a half-cup-shaped optical element, a rotation of 180 °. In alternative embodiments, the optical element may be in the shape of a cone or a half cone obtained by rotating the two-dimensional cross-sectional views shown in fig. 5, 6 or 7 by 360 ° and 180 °, respectively, about an axis parallel to and remote from the light-emitting element. In another embodiment, the optical element may be in the form of a linear optical element, with cross-sectional views as shown in fig. 5, 6 and 7. Other forms of optical elements will be readily understood by those skilled in the art.

[00112] In another embodiment, the optical system comprises a plurality of microlenses or microlens arrays designed to redirect the emission of the light-emitting elements, or a portion thereof, to a common point or optionally to produce a collimated illumination output.

[00113] In another embodiment, the optical system includes a Diffractive Optical Element (DOE) that serves as the primary optical element to generate the desired light intensity distribution from the light-emitting element. The DOE changes the optical path of light incident thereon using diffraction and can be combined with other optical systems to process the luminous distribution produced by the illumination module.

[00114] In another embodiment, the optical system comprises a Photonic crystal structure as described, for example, in s.fan, p.r.villeneuve, j.d.journal. poulos and e.f.schubert, 1997, "Photonic crystal light Emitting Diodes", SPIE vol.3002, pages 67-73, which, when placed or deposited directly on a light Emitting element, can be designed to enhance the emission of the light Emitting element by reducing the level of total internal reflection within the light Emitting element, and which can further process the light intensity distribution of the light Emitting element.

[00115] In another embodiment of the invention, the optical system may comprise a secondary optical system, wherein the secondary optical system may be a DOE for further altering the light intensity distribution. Furthermore, the secondary optical system may optionally be a randomly oriented diffractive multi-grating structure that exhibits iridescence over a wide viewing angle, such as those described in t. 2342-.

[00116] In another embodiment, the optical system comprises a secondary optical system comprising one, more or a combination of reflective and/or refractive and/or diffractive optical elements. For example, the reflective optical element may comprise a parabolic reflector or an elliptical reflector. For example, the refractive optical element may comprise a Fresnel lens, a generally plano-convex, a biconvex, a concave-convex lens, and the diffractive optical element may comprise a holographic and kinoform (kinoform) diffuser.

[00117] In another embodiment of the invention, the optical elements of the optical system may be designed such that the geometric luminous distribution of the lighting module is dynamically controlled by the drive and control system or an external operator. The optical performance of the optical system can be varied in a number of ways. The light emitting elements may be combined with fluid lenses featuring electrostatically adjustable focusing capabilities, as disclosed for example in US patent 2,062,468, or with liquid crystal lenses. Applying an electric field across the fluid lens causes the lens curvature to change and then the focal length to change. By applying an inhomogeneous electric field over the liquid crystal material, a gradient refractive index profile can be generated, which can change the focal length of the controllable optical system. Optionally, the optical system may include means for mechanically adjusting one or more optical elements therein, thereby providing a way to dynamically change the treatment level of illumination by the optical system.

[00118] In one embodiment of the invention, the function of the optical system is to sample the illumination produced by the light-emitting elements to the light sensor or array thereof to feed back the emission characteristics to the drive and control system. In one embodiment, the optical system includes an optical element that reflects or transmits a portion of the illumination emitted by the light-emitting element onto the light sensor or light sensor array. Such an optical element may optionally be connected to a form of light guide capable of directing illumination to the light sensor.

[00119] In one embodiment, a rod-like structure is mounted above the sensor or sensors, providing optical feedback of the light intensity and spectral distribution of the illumination. The surface of the rod may be patterned to preferentially receive illumination from nearby light-emitting elements and absorb, or reflect illumination in other directions. The illumination received inside the rod-shaped structure may preferably be directed towards the light sensor or sensors. In another embodiment the rod-like structure may be connected to or be part of the last optical element or a window associated with the optical system. In this configuration, the rod provides a way to concentrate some of the emission trapped in the optical element to the light sensor or sensor array by means of total internal reflection or Fresnel reflection. In another embodiment, one or more optical elements may be designed to leak a desired amount of emission of the light-emitting element from one or more predetermined locations. The predetermined position may be selected such that the leaked emissions are directly incident on the light sensor or sensor array, or selected such that the leaked emissions of each sub-module are directed onto the light sensor or sensor array through a hollow or solid light guide. Such a light guide may comprise a mixing chamber for mixing the contributions of all sub-modules.

[00120] In one embodiment of the invention, the optical system is designed to diffuse the direct view of the light-emitting element so that its brightness is within industry-standard thresholds established for eye safety.

Communication system

[00121] In one embodiment of the invention, the lighting module comprises a communication module providing a means for communicating the drive and control system with a network of other said lighting modules and other control devices external to the lighting module. The communication system may connect the lighting module to a network and may enable data transmission using prior art data transmission media and data transmission protocol ranges known to those skilled in the art. The data transmission medium may be, for example, an ethernet, fiber optic, wireless or infrared communication system. Depending on the communication needs, examples of suitable protocols include analog 0-10VDC, Digital Addressable Lighting Interface (DALI), ESTA protocols (including DMX512A, RDM, and CAN), IEEE 802.11 wireless protocols (including Bluetooth and Zigbee), infrared protocols (including IrDA and Ultra Far Infrared (UFIR)), or any other protocol that is readily understood.

[00122] The communication system may provide a way of operating the lighting modules in an integrated manner in the other said array of lighting modules. Each lighting module may have a communication system and associated data transmission capabilities and may further be integrated into a communication network connecting the array of lighting modules. For example, the data transmission relates to radiant flux of the light-emitting elements, daylight and/or ambient color temperature, lighting module and board temperature, enabling the array of lighting modules to operate in a uniform manner.

[00123] In one embodiment of the invention, the communication system may enable the drive and control system to transmit or receive data via one or more physical forms of communication, including a hardwired serial or parallel bus, a fiber optic receiver or transceiver, a wireless receiver or transceiver, an infrared receiver or transmitter, or a visible light receiver. The network topology may be selected from bus, star, token ring, mesh, or wireless, for example. Alternative network topologies will be readily understood by those skilled in the art.

[00124] In one embodiment of the invention, the communication system may implement a network physical layer selected from, for example, those including hard-wire, fiber optic, wireless, infrared, or visible light. In another embodiment, the communication system may implement a network including a visible light emitter and a receiver, wherein the emitter is a light emitting element, and wherein the luminous flux output of the light emitting element is modulated with serial data.

[00125] In one embodiment of the invention, other control devices external to the lighting module may include occupancy sensors, daylight sensors, timers, other lighting networks, and building management systems.

[00126] The invention will now be described with reference to specific embodiments. It should be understood that the following examples are intended to describe embodiments of the invention and are not intended to limit the invention in any way.

Examples

Example 1:

[00127] Fig. 8 illustrates a first embodiment of the present invention integrated into a multi-lighting module Quad Flat Pack (QFP) package. The lighting unit comprises a plurality of light emitting elements 300, which further comprise proximate optical elements. The reflector optical element 310 handles the emission of the light emitting element in the desired direction and then interacts with the secondary optical element 320 if provided. In one embodiment, the secondary optical element may be an embedded optical element, such that the optical element can be easily removed or inserted. The light emitting element may be mounted on the CVD diamond substrate 370 by using a heat conductive adhesive so as to have thermal conductivity therein. The heat pipe 360 is in direct thermal contact with the CVD diamond substrate and the thermal shell may be held in a desired position by the housing 350. The heat pipe may transfer heat generated by the light emitting element away therefrom. Furthermore, the lighting unit comprises a substrate 340, which may be manufactured, for example, from FR4 (woven glass reinforced epoxy) or, if desired, an optional MCPCB. Electronic components 330 are mounted on a substrate 340 that includes a controller, feedback system, and other required electronics. The tracks on the substrate 340 may, for example, provide a means of interconnection between the light emitting elements and a controller or other electrical device as desired. In such embodiments, the sensor forming part of the feedback system may be mounted in proximity to the light emitting elements, for example, to one or more light emitting elements within each reflector optical element. Optionally, the sensor may be disposed on the substrate 340, wherein the optical system may provide a means for directing a portion of the emission of the light-emitting elements.

Example 2:

[00128] FIG. 9 illustrates a second embodiment of the invention formed as a modular lighting unit torch lamp. The light emitting element 210 is mounted on a thermally conductive substrate 290 that is thermally bonded to the heat pipe 220, thereby transferring heat from the light emitting element to the heat pipe and then dissipating it. The ends of the heat pipes are in contact with the housing 250, which may include slits 280 to enable air to flow within the housing to provide additional heat dissipation. A PC board 240, which is below and in operative contact with the light emitting elements, includes a drive and control system mounted thereon, wherein such PC board may be operatively connected to a power supply 260, for example. Further, the emission of the light emitting element can be processed by the light diffuser 230.

Example 3:

[00129] Fig. 10 illustrates a third embodiment of the invention formed as a modular lighting unit lighting device, wherein the light emitting elements 420 are mounted on a substrate or heat pipe 410, or optionally the light emitting elements may be mounted directly on a side wall of the heat pipe. The control board 430 is below the heat pipe and operatively connected to the light emitting elements. A diffuser/reflector 400 is provided to treat the emission of the light emitting elements.

Example 4:

[00130] Fig. 11 illustrates a lighting unit comprising a plurality of sub-modules interconnected together. Each sub-module comprises a light emitting element 520, an optical element 540 and a heat pipe 530 in close thermal contact with the light emitting element. The sub-modules may be connected together by a PC board on which other electronic components 500 and 510 may be mounted, which may include electronics for providing drive, control and feedback to one or more of the sub-modules. For example, each sub-module may include one or more light-emitting elements capable of producing white light. The light-emitting elements may comprise monochromatic, polychromatic or broadband wavelength emitting light-emitting elements or combinations thereof. Further, the light emitting elements may include primary or secondary light emitting elements, where the secondary light emitting elements may be phosphor coated LEDs or quantum dot LEDs.

Example 5:

[00131] Fig. 12 illustrates a cross section of a lighting unit in which the lighting and electronic components are designed in a stacked form. Within the housing 630 of the lighting unit, power, drive, feedback, control and other required electronics are provided on the PC boards 640, 650 and 660 in a stacked configuration. There may optionally be several or more PC boards depending on the required electronics. These PC boards may be in thermal contact with, for example, one or more heat pipes 670, which may provide a way to transfer heat from the PC board to a heat sink 680 or other heat dissipation system. In this way, the PC boards can be arranged more densely due to the thermal regulation provided by the heat pipes or other thermal management system, so that smaller lighting units can be manufactured. In addition, the heat pipe is in close thermal contact with the one or more light-emitting elements 620, thereby enabling removal of the generated heat. In addition, the emission of the light emitting element can be processed by an optical element 600 disposed proximate to the light emitting element. Light and/or thermal sensors 610 may be disposed proximate to the light-emitting elements so that information regarding the chromaticity of the emission may be gathered in addition to the junction temperature of the light-emitting elements. The light emitting element and the one or more sensors may be mounted on, for example, an FR4 board or an MCPCB. The PC board, the light emitting element and the one or more sensors are operatively connected to each other such that each of these elements provides the respective desired function.

Example 6:

[00132] Fig. 13 is a diagram of a lighting module of one embodiment of the present invention. The light emitting elements and the optical system are formed as light clusters 730, wherein the light clusters are thermally connected to one or more heat pipes 700. The heat transferred by the heat pipes is dissipated using a plurality of heat sinks 710 formed as finned heat sinks to enhance heat dissipation. The optical feedback system 740 is configured relative to the plurality of light clusters such that optical characteristics of the illumination produced by the plurality of light-emitting elements can be provided. The electronic components required to operate the optical module are mounted on the plurality of PCB boards 720. These required electronic components include drive and control systems.

Example 7:

[00133] Fig. 14 is a lighting module of another embodiment of the present invention. The lighting module of the present embodiment is similar to that shown in fig. 13, wherein the light emitting elements and the optical system 850 are formed as light clusters, wherein the light clusters of the light emitting elements are thermally connected to a plurality of heat pipes 800. The heat pipe passes through the PCB board so as to be in thermal contact with the light clusters of the light emitting elements. A plurality of heat sinks 810 in the form of designed ferrules are used to dissipate the heat transferred by the heat pipes. A heat dissipating sleeve surrounds the heat pipe, wherein thermal grease or other material may be used to enhance thermal contact therebetween. The heat sink sleeve may have fins along its length to enhance heat dissipation. The optical feedback system 840 is configured with respect to the plurality of optical clusters of light-emitting elements such that optical characteristics of the illumination produced by the plurality of light-emitting elements can be provided. The electronic components required to operate the light module are mounted on the PCB 825, and the light emitting elements are mounted on the PCB 820 together with the sensor system. In one embodiment, in which the control module and the driver and control system for the driver module are formed, the driver module and the controller module may be mounted on different PCBs. For example, the control module may be mounted on PCB board 820 and the driver module may be mounted on PCB board 825.

[00134] Fig. 15 illustrates the embodiment of fig. 14, wherein the optical system 850 has been separated from the light emitting module, thereby exposing the set of light emitting elements 860 mounted on the PCB 820.

[00135] While embodiments of the invention have been described, it will be obvious that the invention may be practiced in a variety of forms. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Example 8:

[00136] Fig. 16 illustrates a lighting module of one embodiment of the present invention, which may be mounted within a molded housing 1001. The optical system includes a four-stage optical element 1002, a three-stage optical element 1003 for collimating light, a secondary optical element 1004 for mixing light and configured as a tapered tube, where the primary optical element is configured proximate to the light-emitting element and the primary optical element is configured to enhance light extraction by the light-emitting element.

[00137] The substrate on which the light emitting elements are mounted is designed to be highly thermally conductive and is configured to interface with a heat pipe 1008 to provide a way to efficiently transfer heat away from the light emitting elements. The heat pipe is thermally coupled to a heat sink 1009 to provide a means of dissipating heat into the environment, such as ambient air.

[00138] The LED PCB 1006 has mounted thereon a control module, one or more sensors, and a communication system, all of which are configured to communicate with the light emitting elements. In addition, the driver PCB 1007 has mounted thereon a driver module in operative communication with the control module.

Example 9:

[00139] Fig. 17 illustrates a lighting module of one embodiment of the present invention. The optical system includes a tertiary optical element 1013 for collimating light, a secondary optical element 1014 for mixing light and configured as a hexagonal tapered tube, where the primary optical element is configured proximate to the light-emitting element and the primary optical element is configured to enhance light extraction by the light-emitting element.

[00140] The substrate on which the light emitting elements are mounted is designed to be highly thermally conductive and is configured to interface with a heat pipe 1018 to provide a means for efficiently transferring heat away from the light emitting elements. The heat pipe is thermally coupled to heat sink 1019, thereby providing a means of dissipating heat into the environment, such as ambient air.

[00141] The LED PCB 1016 has mounted thereon a control module, one or more sensors, and a communication system, all of which are configured to communicate with the light emitting elements. A substrate on which a light emitting element is mounted under the LED PCB, with a hole at the position of the light emitting element. In addition, the driver PCB 1017 has mounted thereon a driver module in operative communication with the control module.

[00142] The mounting pins 1010 may be mechanically coupled to the lighting module and may provide a means of mechanical coupling between the lighting module and the housing.

Example 10:

[00143] FIG. 18 illustrates an optical system according to an embodiment of the present invention. The optical system comprises a secondary optical element 1030 for mixing light and configured as a cone, wherein the primary optical element 1021 is arranged proximate to the light emitting element, the primary optical element being configured to enhance light extraction of the light emitting element.

[00144] The substrate on which the light emitting elements are mounted is designed to be highly thermally conductive and is configured to interface with a heat pipe to provide a way to efficiently transfer heat away from the light emitting elements.

[00145] The LED PCB 1023 has mounted thereon a control module, one or more sensors and a communication system, all of which are configured to communicate with the light emitting elements. A substrate 1005 on which light emitting elements are mounted is mounted under the LED PCB with a hole at the position of the light emitting elements.

[00146] All patents, publications, patent applications, and database entries referred to in this specification are herein incorporated by reference in their entirety to the same extent as if each individual patent, publication, or database entry was specifically and individually indicated to be incorporated by reference.

Claims (23)

1. An integrated lighting module comprising:

(a) one or more light-emitting elements for producing illumination;

(b) an optical system optically connected to the one or more light-emitting elements and for processing the illumination;

(c) a feedback system for collecting information representative of an operating characteristic of the one or more light-emitting elements, the feedback system generating one or more signals representative of the information;

(d) a thermal management system in thermal contact with the one or more light-emitting elements, the thermal management system to conduct heat away from the one or more light-emitting elements;

(e) a drive and control system for receiving the one or more signals from the feedback system, the drive and control system regulating input power, generating control signals and sending control signals to the one or more light-emitting elements, the control signals generated based on predetermined control parameters and the one or more signals.

2. The integrated lighting module of claim 1, wherein the thermal management system comprises one or more heat pipes or thermosiphons, each heat pipe or thermosiphon having an evaporator end.

3. The integrated lighting module of claim 2, wherein the one or more heat pipes or thermosiphons are physically connected to one or more of the one or more light-emitting elements.

4. The integrated lighting module of claim 2, wherein the one or more light-emitting elements are mounted on a thermally conductive substrate, and wherein the one or more heat pipes or thermosiphons are in direct thermal contact with the thermally conductive substrate.

5. The integrated lighting module of claim 4, wherein an evaporator end of the one or more heat pipes or thermosiphons is integrated into the thermally conductive substrate.

6. The integrated lighting module of claim 1, wherein the thermal management system comprises one or more thermal devices selected from the group consisting of peltier-effect thermoelectric cooling devices, thermionic devices, and fluid cooling systems.

7. The integrated lighting module of claim 2, wherein the thermal management system further comprises one or more heat sinks in thermal connection with the one or more heat pipes or thermosiphons, the one or more heat sinks for dissipating heat transferred by the one or more heat pipes or thermosiphons.

8. The integrated lighting module of claim 1, wherein the feedback system comprises one or more light sensors for generating a signal representative of the illumination produced by the one or more light-emitting elements, the signal representative of any one or more characteristics selected from the group consisting of illumination color, illumination correlated color temperature, and illumination intensity.

9. The integrated lighting module of claim 1, wherein the feedback system comprises one or more temperature sensors for generating signals representative of an operating temperature of the one or more light-emitting elements.

10. The integrated lighting module of claim 8, wherein the feedback system further comprises a temperature sensor for generating a signal representative of an operating temperature of the one or more light sensors.

11. The integrated lighting module of claim 1, wherein one or more of the one or more light sensors are further configured to generate a signal representative of ambient light conditions.

12. The integrated lighting module of claim 8, wherein the one or more light sensors comprise a color filter for limiting light sensor response to a predetermined wavelength range.

13. The integrated lighting module of claim 8, wherein the one or more light sensors are connected to circuitry for processing signals generated by the one or more light sensors, wherein processing the signals includes one or more of signal conditioning, signal amplification, gain control, and integration time control.

14. The integrated lighting module of claim 1, wherein the one or more light-emitting elements are electrically connected for individual control by the drive and control system.

15. The integrated lighting module of claim 1, wherein the one or more light-emitting elements emit light having a color selected from the group consisting of white, red, green, blue, cyan, and amber.

16. The integrated lighting module of claim 1, wherein the drive and control system digitally controls the one or more light-emitting elements using pulse width modulation or pulse code modulation.

17. The integrated lighting module of claim 1, wherein the drive and control system comprises a switching converter operatively connected with selected ones of the one or more light-emitting elements, the switching converter providing means for regulating current flow to the selected light-emitting elements based on a detected voltage drop across the selected light-emitting elements.

18. The integrated lighting module of claim 1, wherein the drive and control system and the one or more light-emitting elements are mounted on a common thermally conductive substrate, wherein the thermal management system further provides a means for conducting heat away from the drive and control system.

19. The integrated lighting module of claim 1, wherein the drive and control system is operatively connected to a user interface to provide a way for a user to vary the lighting produced by the integrated lighting module.

20. The integrated lighting module of claim 1, wherein the optical system comprises one or more optical elements for processing illumination of the one or more light-emitting elements, wherein processing comprises one or more of light extraction, light collection, light collimation, and light mixing.

21. The integrated lighting module of claim 8, wherein the optical system comprises an optical element for capturing and directing a portion of the illumination toward the one or more light sensors.

22. The integrated lighting module of claim 1, further comprising a communication system operatively connected to the drive and control system, the communication system being operable to input data to or output data from the lighting module or both.

23. A networked lighting system, comprising:

(a) two or more integrated lighting modules, each module comprising:

(i) one or more light-emitting elements for producing illumination;

(ii) an optical system optically connected to the one or more light-emitting elements and for processing the illumination;

(iii) a feedback system for collecting information representative of an operating characteristic of the one or more light-emitting elements, the feedback system generating one or more signals representative of the information;

(iv) a thermal management system in thermal contact with the one or more light-emitting elements, the thermal management system to conduct heat away from the one or more light-emitting elements;

(v) a drive and control system for receiving the one or more signals from the feedback system, the drive and control system regulating input power, generating control signals and sending control signals to the one or more light-emitting elements, the control signals generated based on predetermined control parameters and the one or more signals; and

(vi) a communication system operatively connected to the drive and control system, the communication system being communicable between the two or more integrated lighting modules.