HK1087190A

HK1087190A - Method and system for sensing light using interferometric elements

Info

Publication number: HK1087190A
Application number: HK06109187.8A
Authority: HK
Inventors: 马尼什．科塔里
Original assignee: Idc公司
Priority date: 2004-09-27
Filing date: 2006-08-18
Publication date: 2006-10-06

Abstract

Certain embodiments of the invention provide a light sensor comprising at least one interferometric element that absorbs light in at least one wavelength. The interferometric element comprises a first surface and a second surface substantially parallel to the first surface. The second surface is spaced a gap distance from the first surface in a direction substantially perpendicular to the first surface. The light wavelength absorbed is dependent on the gap distance. The interferometric element further comprises a temperature sensor. The temperature sensor is responsive to changes in temperature of at least a portion of the interferometric element due to absorption of light by the interferometric element.

Description

Method and system for detecting light using interferometric elements

Technical Field

The technical field of the invention relates to micro-electromechanical systems (MEMS), and more particularly, the technical field of the invention relates to an electrical connection architecture for an array of MEMS elements.

Background

Microelectromechanical Systems (MEMS) include micromechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. One type of MEMS device is known as an interferometric modulator. An interferometric modulator may comprise a pair of conductive plates, one or both of which may be partially transparent and capable of relative motion upon application of an appropriate electrical signal. One of the plates may comprise a stationary layer deposited on a substrate and the other plate may comprise a metal diaphragm suspended from the stationary layer.

In some display configurations, an array of individually actuatable interferometric light modulators is used as display elements. The manner in which the optical modulators are electrically connected may provide control voltages or signals for individually actuating each optical modulator.

Disclosure of Invention

The system, method and apparatus of the present invention have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of the invention, its more prominent features will now be discussed briefly. After reviewing this discussion, and particularly after reading the section entitled "detailed description of certain embodiments" one will understand how the features of this invention provide advantages over other display devices.

Certain embodiments of the present invention provide a light sensor comprising at least one interferometric element that absorbs light of at least one wavelength. The interferometric element comprises a first surface and a second surface substantially parallel to the first surface. The second surface is spaced from the first surface by a spacing in a direction substantially perpendicular to the first surface. The wavelength of the absorbed light depends on the spacing. The interferometric element further comprises a temperature sensor. The temperature sensor may be responsive to a change in temperature of at least a portion of the interferometric element due to absorption of light by the interferometric element.

In certain embodiments, the light sensor comprises a plurality of interferometric elements. Each interferometric element has a corresponding pitch and absorbs light of at least one wavelength. In certain embodiments, each interferometric element comprises substantially the same pitch as the other interferometric elements. In certain other embodiments, the plurality of interferometric elements constitutes two or more subsets of interferometric elements. Each interferometric element in a subset comprises substantially the same pitch as the other interferometric elements in the subset. Each subset having a different pitch and absorbing at least one different wavelength of light.

In some embodiments, the light sensor further comprises a color filter array. Each color filter is positioned such that light impinging on a corresponding interferometric element propagates through the color filter. Each color filter substantially transmits at least one wavelength of light corresponding to the interferometric element.

In certain embodiments, the first surface of the interferometric element is a fixed surface and the second surface is a movable surface. In a first state of the interferometric element, the movable surface is spaced a first distance from the fixed surface in a direction substantially perpendicular to the fixed surface. In a second state, the movable surface is spaced from the fixed surface in a direction substantially perpendicular to the fixed surface by a second distance different from the first distance. In certain embodiments, the first distance or the second distance is approximately zero.

In certain embodiments, the interferometric elements comprise two or more colors. In certain embodiments, the interferometric element comprises one color of light (e.g., red, green, or blue).

In certain embodiments, at least one interferometric element is used as a light sensor. In certain other embodiments, a plurality of interferometric elements are used for image capture.

Drawings

FIG. 1 is an isometric view depicting a portion of one embodiment of an interferometric modulator display in which a movable reflective layer of a first interferometric modulator is in a released position and a movable reflective layer of a second interferometric modulator is in an actuated position.

FIG. 2 is a system block diagram illustrating one embodiment of an electronic device including a 3 × 3 interferometric modulator display.

FIG. 3 is a diagram of movable mirror position versus applied voltage for one exemplary embodiment of an interferometric modulator of FIG. 1.

FIG. 4 is a schematic diagram of a set of row and column voltages that may be used to drive an interferometric modulator display.

Fig. 5A and 5B show an exemplary timing diagram for row and column signals that may be used to write a frame of display data to the 3 x 3 interferometric modulator display of fig. 3.

Fig. 6A is a cross-sectional view of the device of fig. 1.

FIG. 6B is a cross-sectional view of an alternative embodiment of an interferometric modulator.

FIG. 6C is a cross-sectional view of another alternative embodiment of an interferometric modulator.

FIG. 7 schematically shows an interferometric element compatible with embodiments described herein.

FIG. 8 schematically illustrates a plurality of interferometric elements, each having a different pitch.

FIG. 9 schematically shows a plurality of interferometric elements, each having a temperature sensor responsive to a different temperature range.

FIGS. 10A and 10B schematically show two embodiments of a light sensor having a plurality of interferometric elements of substantially equal pitch and a plurality of color filters.

FIG. 11 is a graph of transmission spectra for a set of three exemplary color filter materials compatible with embodiments described herein.

12A, 12B, and 12C are three graphs showing the superposition of the transmission spectrum of the color filter material of FIG. 11 and the emission spectrum of a backlight.

FIG. 13 is a system block diagram illustrating one embodiment of an electronic device including an interferometric element having a temperature sensor for a side light source.

FIG. 14 is a system block diagram illustrating one embodiment of an electronic device including an interferometric element having a temperature sensor for a backlight.

FIG. 15 shows a series of example steps for detecting light using an electronic device having an interferometric element and temperature sensor.

16A and 16B are system block diagrams illustrating one embodiment of a visual display device comprising a plurality of interferometric modulators.

Detailed Description

An exemplary embodiment of a light sensor having at least one interferometric element and a temperature sensor is described herein. The interferometric element absorbs ambient light of a wavelength on a surface of the interferometric modulator in the form of heat. The absorbed heat is detected by the temperature sensor. The temperature sensor may be a contact or non-contact sensor. The temperature sensor is responsive to heat absorbed by a surface of the interferometric modulator. The temperature sensor may output data indicative of the sensed temperature, such as a voltage. In certain embodiments, the output data is processed and stored as a digital image. In certain other embodiments, the output data is used to set the amount of front or back light illuminating a display device to make the display device more readable in ambient light.

The following detailed description is directed to certain specific embodiments of the invention. However, the invention can be embodied in a multitude of different ways. In the description, reference is made to the drawings wherein like parts are designated with like numerals throughout. As will be apparent from the following description, the invention may be implemented in any device that is configured to display an image, whether in motion (e.g., video) or stationary (e.g., still image), and whether textual or pictorial. More specifically, it is contemplated that the present invention may be implemented in or associated with a wide variety of electronic devices such as, but not limited to: mobile telephones, wireless devices, Personal Data Assistants (PDAs), handheld or portable computers, GPS receivers/navigators, cameras, MP3 players, camcorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., odometer display, etc.), cockpit controls and/or displays, display of camera views (e.g., display of a rear view camera in a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., display of images on a piece of jewelry). MEMS devices of similar construction to the MESE devices described herein can also be used in non-display applications such as in electronic switching devices.

One interferometric modulator display embodiment comprising an interferometric MEMS display element is shown in FIG. 1. In these devices, the pixels are in either a bright or dark state. In the bright ("on" or "open") state, the display element reflects a large portion of incident visible light to the user. When in the dark ("off" or "closed") state, the display element reflects little incident visible light to the user. Depending on the embodiment, the light reflectance properties of the "on" and "off" states may be reversed. MEMS pixels can be configured to reflect predominantly at selected colors, allowing for a color display in addition to black and white.

FIG. 1 is an isometric view depicting two adjacent pixels in a series of pixels of a visual display, wherein each pixel comprises a MEMS interferometric modulator. In certain embodiments, an interferometric modulator display comprises a row/column array of these interferometric modulators. Each interferometric modulator includes a pair of reflective layers positioned at a variable and controllable distance from each other to form a resonant optical cavity with at least one variable dimension. In one embodiment, one of the reflective layers is movable between two positions. In the first position, referred to herein as the released state, the movable layer is positioned relatively far from a fixed partially reflective layer. In the second position, the movable layer is positioned closer to the partially reflective layer. Incident light that reflects from the two layers interferes constructively or destructively depending on the position of the movable reflective layer, producing either an overall reflective or non-reflective state for each pixel.

The portion of the pixel array shown in FIG. 1 includes two adjacent interferometric modulators 12a and 12 b. In the interferometric modulator 12a on the left, a movable highly reflective layer 14a is illustrated in a released position at a predetermined distance from a fixed partially reflective layer 16 a. In the interferometric modulator 12b on the right, a movable highly reflective layer 14b is illustrated in an actuated position adjacent to a fixed partially reflective layer 16 b.

The fixed layers 16a, 16b are electrically conductive, partially transparent and partially reflective, and may be fabricated, for example, by depositing one or more layers each of chromium and indium tin oxide on a transparent substrate 20. The layers are patterned into parallel strips and may form row electrodes in a display device, as will be described further below. The movable layers 14a, 14b may be formed as a series of parallel strips of a deposited metal layer or layers (orthogonal to the row electrodes 16a, 16 b) deposited on top of posts 18 and an intervening sacrificial material deposited between the posts 18. After the sacrificial material has been etched away, the deformable metal layers are separated from the fixed metal layers by a defined air gap 19. The deformable layers may be formed from a highly conductive and reflective material, such as aluminum, and the strips may form column electrodes in a display device.

When no voltage is applied, the cavity 19 remains between the layers 14a, 16a and the deformable layer is in a mechanically relaxed state as shown by the pixel 12a in FIG. 1. However, after application of a potential difference to a selected row and column, the capacitor formed at the intersection of the row and column electrodes at the corresponding pixel is charged, and electrostatic forces pull the electrodes together. If the voltage is high enough, the movable layer deforms and is forced against the fixed layer (a dielectric material (not shown in this figure) may be deposited over the fixed layer to prevent shorting and control the separation distance), as shown in the right pixel 12b in FIG. 1. The behavior is the same regardless of the polarity of the applied potential difference. It can thus be seen that row/column actuation that can control the reflective vs. non-reflective pixel states is analogous in many ways to that used in conventional LCD and other display technologies.

FIGS. 2-5 illustrate one exemplary process and system for using an array of interferometric modulators in a display application. FIG. 2 is a system block diagram illustrating one embodiment of an electronic device that may embody aspects of the invention. In the exemplary embodiment, the electronic device includes a processor 21, which may be any general purpose single chip orMulti-chip microprocessors, e.g. ARM, Pentium^*、Pentium II^*、PentiumIII^*、Pentium IV^*、Pentium^*Pro、8051、MIPS^*、Power PC^*、ALPHA^*Or any special purpose microprocessor such as a digital signal processor, microcontroller, or programmable gate array. As is conventional in the art, the processor 21 may be configured to execute one or more software modules. In addition to executing an operating system, the processor may be configured to execute one or more software applications, including a web browser, a telephone application, an email program, or any other software application.

In one embodiment, the processor 21 is further configured to communicate with an array controller 22. In one embodiment, the array controller 22 includes a row driver circuit 24 and a column driver circuit 26 that provide signals to a pixel array 30. The cross-sectional view of the array shown in FIG. 1 is shown by line 1-1 in FIG. 2. For MEMS interferometric modulators, the row/column actuation protocol may take advantage of the hysteresis properties of these devices shown in FIG. 3. It may require, for example, a 10 volt potential difference to cause a movable layer to deform from the released state to the actuated state. However, when the voltage is reduced from this value, the movable layer will retain its state as the voltage drops back below 10 volts. In the exemplary embodiment of FIG. 3, the movable layer does not release completely until the voltage drops below 2 volts. Thus, in the example shown in FIG. 3, there is a range of voltage, approximately 3-7 volts, within which there exists a window of applied voltage within which the device is stable in either the released or actuated state. This is referred to herein as the "hysteresis window" or "stability window". For a display array having the hysteresis characteristics of FIG. 3, the row/column actuation protocol can be designed to apply a voltage difference of about 10 volts to the pixels to be actuated in the selected pass and a voltage difference of approximately 0 volts to the pixels to be released during row strobing. After the strobe, the pixels are exposed to a steady state voltage difference of about 5 volts such that they remain in whatever state the row strobe put them in. After being written, each pixel sees a potential difference within the "stability window" of 3-7 volts in this example. This feature makes the pixel design shown in fig. 1 stable under the same applied voltage conditions in either an actuated or released pre-existing state. Since each pixel of the interferometric modulator, whether in the actuated or released state, is essentially a capacitor formed by the fixed and moving reflective layers, this stable state can be held at a voltage within the hysteresis window with almost no power dissipation. Essentially no current flows into the pixel if the applied potential is constant.

In typical applications, a display frame may be created by asserting the set of column electrodes in accordance with the desired set of actuated pixels in the first row. A row pulse is then applied to the row 1 electrode, actuating the pixels corresponding to the asserted column lines. The asserted set of column electrodes is then changed to correspond to the desired set of actuated pixels in the second row. A pulse is then applied to the row 2 electrode, actuating the appropriate pixels in row 2 in accordance with the asserted column electrodes. The row 1 pixels are unaffected by the row 2 pulse, and thus remain in the state they were set to during the row 1 pulse. The above steps may be repeated for the entire series of rows in a sequential manner to form the frame. Typically, the frames are refreshed and/or updated with new display data by continually repeating the process at some desired number of frames per second. A wide variety of protocols for driving row and column electrodes of pixel arrays to produce display frames are also well known and may be used in conjunction with the present invention.

Fig. 4 and 5 show one possible actuation protocol for forming a display frame on the 3 x 3 array of fig. 2. Figure 4 shows a possible set of row and column voltage levels that may be used for pixels having the hysteresis curves of figure 3. In the embodiment of FIG. 4, actuating a pixel involves setting the appropriate column to-Vbias, and the appropriate row to + Δ V, which may correspond to-5 volts and +5 volts, respectively. Releasing a pixel is accomplished by setting the corresponding column to + Vbias, and the corresponding row to the same + deltav, thereby creating a 0 volt potential difference across the pixel. In those rows where the row voltage is held at 0 volts, the pixels are stable in the state they were originally in, regardless of whether the column is at + Vbias, or-Vbias.

FIG. 5B is a timing diagram showing a series of row and column signals applied to the 3 × 3 array of FIG. 2, which will result in the display arrangement of FIG. 5A, where actuated pixels are non-reflective. Prior to writing the frame shown in FIG. 5A, the pixels can be in any state, in this example, all the rows are at 0 volts, and all the columns are at +5 volts. Under these applied voltages, all pixels are stable in their existing actuated or released states.

In the frame shown in FIG. 5A, pixels (1, 1), (1, 2), (2, 2), (3, 2) and (3, 3) are activated. To achieve this, during a row time for row 1, columns 1 and 2 are set to-5 volts, and column 3 is set to +5 volts. This does not change the state of any pixels, since all pixels remain within the 3-7 volt stability window. Thereafter, row 1 is strobed with a pulse that rises from 0 volts to 5 volts and then falls back to 0 volts. Thereby actuating the pixels (1, 1) and (1, 2) and releasing the pixels (1, 3). No other pixels in the array are affected. To set row 2 as desired, column 2 is set to-5 volts, and columns 1 and 3 are set to +5 volts. Thereafter, applying the same strobe to row 2 will actuate pixel (2, 2) and release pixels (2, 1) and (2, 3). Again, no other pixels in the array are affected. Similarly, row 3 is set by setting columns 2 and 3 to-5 volts, and column 1 to +5 volts. The row 3 strobe sets the row 3 pixels to the state shown in FIG. 5A. After writing the frame, the row potentials are 0, while the column potentials can remain at either +5 or-5 volts, and the display will thereafter be stable in the arrangement shown in FIG. 5A. It will be appreciated that the same procedure can be used for arrays consisting of tens or hundreds of rows and columns. It will also be appreciated that the timing, sequence, and levels of voltages used to perform row and column actuation can be varied widely within the general principles outlined above, and the above example is exemplary only, and any actuation voltage method can be used with the present invention.

The detailed structure of interferometric modulators that operate in accordance with the principles set forth above may vary widely. For example, FIGS. 6A-6C show three different embodiments of the moving mirror structure. FIG. 6A is a cross-sectional view of the embodiment of FIG. 1, wherein a strip of metal material 14 is deposited on orthogonally extending supports 18. In FIG. 6B, the moveable reflective material 14 is attached to supports at the corners only, on tethers 32. In FIG. 6C, the moveable reflective material 14 is suspended from a deformable layer 34. This embodiment has several advantages because the structural design and materials used for the reflective material 14 can be optimized with respect to the optical properties, and the structural design and materials used for the deformable layer 34 can be optimized with respect to the desired mechanical properties. The production of various types of interference devices is described in a number of published documents, including, for example, U.S. published application No. 2004/0051929. The above-described structures may be fabricated using a variety of well-known techniques, including a series of material deposition, patterning, and etching steps.

In certain embodiments, these interferometric elements provide the ability to individually address and transition selected interferometric elements between at least two states having different reflective and transmissive properties. Other non-switchable interferometric elements are also compatible with the embodiments described herein.

FIG. 7 schematically shows an interferometric element 700 having a temperature sensor 708. The illustrated embodiment of the interferometric element 700 is not switchable, and thus does not switch between the "off" and "on" states as described above. However, the description of the interferometric element 700 applies equally to switchable embodiments, including the exemplary switchable embodiments shown in FIGS. 6A, 6B, and 6C. For example, the exemplary switchable embodiments shown in FIGS. 6A, 6B, and 6C may include a temperature sensor 708. In these embodiments, the interferometric elements can be switched between an "off" and an "on" state, and can detect ambient light. The embodiment of the exemplary switchable element having a temperature sensor 708 shown in FIGS. 6A, 6B, and 6C can be beneficial for display electronics that include interferometric elements not only for display purposes, but also for ambient light detection capabilities. For example, the detected characteristics of the interferometric elements may be used to control an optical compensation structure. In some embodiments, the optical compensation structure is a front light, side light, or back light associated with a display electronic device. In these embodiments, the detected intensity and brightness of the ambient light can be preferably used to set how much light illuminates the display electronics to make the display device more readable in ambient light.

The interferometric element 700 is configured to detect ambient light. In some embodiments, temperature sensor 708 provides one or more characteristics of the detected ambient light to an electronic device. Characteristics of ambient light include, but are not limited to, wavelength and intensity. Exemplary electronic devices include cameras and fingerprint sensors. In certain embodiments, the interferometric element 700 detects ambient light having at least one wavelength and one intensity associated with the wavelength. In certain embodiments, a camera device receives and stores these characteristics. To form an image, the camera may receive characteristics from a plurality of adjacent interferometric elements arranged in an array of interferometric elements. In certain embodiments, the received characteristics from the array of interferometric elements are processed and stored as a digital image. The use of the interferometric element 700 as a camera or other image capture device will be described in greater detail below in connection with FIG. 8.

In certain embodiments, both switchable and non-switchable interferometric elements are used in a display electronic device. One or more of the switchable or non-switchable interferometric elements may include a temperature sensor 708. The switchable or non-switchable interferometric element with the sensor may be located inside or outside the array of switched interferometric elements.

The interferometric element 700 comprises a first surface 702 and a second surface 704 substantially parallel to the first surface 702. The second surface 704 is spaced apart from the first surface 702 by a distance d in a direction substantially perpendicular to the first surface 702₀. First surface702 is partially transmissive and partially reflective to the at least one wavelength. The second surface 704 is at least partially reflective to light. Exemplary materials for first surface 702 and second surface 704 include, but are not limited to, chromium or titanium.

The first surface 702 and the second surface 704 form a resonant cavity (e.g., etalon) in which light interferes with itself by reflecting between the first surface 702 and the second surface 704. The interferometric element 700 absorbs light having at least one wavelength. The at least one wavelength is dependent on the separation d₀. In the embodiment schematically illustrated in FIG. 7, the interferometric element 700 further comprises a substrate 706 that is substantially transmissive to the at least one wavelength. Light enters the interferometric element 700 through the substrate 706 and is reflected between the first surface 702 and the second surface 704. At least a portion of the light having at least one wavelength incident on the interferometric element 700 is absorbed by the interferometric element 700. The energy associated with the light absorbed in the first surface 702 is dissipated as heat. Although first surface 702 of some embodiments is located on substrate 706, as schematically shown in fig. 7, in other embodiments there are one or more intervening layers (e.g., dielectric layers) between substrate 706 and first surface 702. In still other embodiments, the interferometric element 700 comprises one or more layers (e.g., dielectric layers) on the first surface 702, such that the first surface 702 is between the layers and the substrate 706.

The interferometric element 700 further comprises a temperature sensor 708. The temperature sensor 708 may be responsive to a change in temperature of at least a portion of the interferometric element 700 due to absorption of light by the interferometric element 700. In the embodiment schematically shown in fig. 7, the temperature sensor 708 is located on the first surface 702 and between the first surface 702 and the second surface 704. Other locations for the temperature sensor 708 are also compatible with the embodiments described herein. In some embodiments, the temperature sensor 708 is positioned adjacent to or spaced apart from the first surface 702. In these embodiments, the temperature sensor 708 may detect a change in temperature of the portion of the first surface 702 by radiation, convection, conduction, or a combination of one or more physical processes that transfer thermal energy. In the exemplary embodiment shown in fig. 6A, 6B, and 6C, the temperature sensor 708 may be located near or adjacent to an optical stack. In certain embodiments, the optical stack includes a fixed layer 16a, 16b and a layer adjacent to the fixed layer. These adjoining layers may include a dielectric layer, a chromium layer, an indium tin oxide layer, and a transparent substrate 20.

In certain embodiments, the absorption and corresponding heat is a function of wavelength. For example, the interferometric element 700 may have different absorption coefficients for red, green, and blue light, thereby generating different amounts of heat for these different wavelengths of incident light. In certain embodiments, the material of the interferometric element 700 is selected to have sensitivity to a selected range of wavelengths. The range of wavelengths that the interferometric element 700 can detect that are compatible with the embodiments described herein include, but are not limited to, visible wavelengths, infrared and ultraviolet wavelengths, Radio Frequency (RF) wavelengths, and X-ray wavelengths.

In some embodiments, temperature sensor 708 comprises a binary device (e.g., a switch) that is in a first state when the temperature is below a predetermined level and in a second state when the temperature is above a predetermined level. Some of these switches are formed using micro-electromechanical system (MEMS) fabrication techniques. In certain other embodiments, the temperature sensor 708 comprises an analog device.

For example, the temperature sensor 708 may be a contact or non-contact sensor. Exemplary temperature contact sensors that can be used with the embodiments described herein include thermocouples, thermistors, Resistance Temperature Detectors (RTDs), fill system thermometers, bimetallic thermometers, and semiconductor temperature sensors. For example, a bimetal thermocouple may be used to generate a voltage difference as a function of temperature. Example non-contact temperature sensors that may be used with the embodiments described herein include radiation thermometers (e.g., pyrometers), thermal imagers, proportional thermometers, optical pyrometers, and fiber optic temperature sensors. Other temperature sensors 708 are also compatible with the embodiments described herein.

In certain embodiments, the temperature sensor 708 has more or less surface area in contact with the first surface 702. Increasing the contact surface area between the temperature sensor 708 and the first surface 702 may advantageously increase the sensitivity of the characteristic measured by the temperature sensor 708.

By absorbing light having at least one wavelength, the temperature of the interferometric element 700 increases, and the temperature sensor 708 responds to this increase in temperature. In certain embodiments, the response of temperature sensor 708 is determined by measuring a change in voltage of temperature sensor 708. In the illustrated embodiment, the temperature sensor 708 measures a voltage (V)₀-V₁)。V₀And V₁The change in voltage corresponds to a change in temperature of the portion of the first surface 702. In certain other embodiments, the temperature sensors 708 measure, for example, current, resistance, and/or deflection, depending on the type of temperature sensor 708 selected.

In certain embodiments, the increase in temperature is dependent on the intensity of the at least one wavelength of light absorbed by the interferometric element 700. The interferometric element 700 thus acts as a photosensor sensitive to the at least one wavelength.

The dimensions of the interferometric element 700 vary according to the micro-fabrication design rules. In semiconductor fabrication, certain embodiments may be realized in which the area of the interferometric element 700 is less than or equal to about one square micron. Other certain embodiments provide an interferometric element 700 having an area less than or equal to about 0.5 square microns. Other dimensions of the interferometric element 700 are also compatible with the embodiments described herein.

FIG. 8 schematically shows a plurality of interferometric elements 700 comprising a set of three interferometric elements 700. A first set 800 of interferometric elements 700 has a pitch d₁Distance d between₁Corresponding to being substantially reflective for a first wavelength range and at least partially absorbing for other wavelengths. A second set 802 of interferometric elements 700 has a pitch d₂Distance d between₂Corresponding to being substantially reflective for a second wavelength range and at least partially absorbing for other wavelengths. Interference typeA third set 804 of elements 700 has a pitch d₃Distance d between₃Corresponding to being substantially reflective for a third wavelength range and at least partially absorptive for other wavelengths. The temperature sensor 708 may be fabricated using different materials and/or have a different architecture (MEMS/bi-metal, etc.) for the three different gaps to optimize its sensitivity.

In certain embodiments, each wavelength range comprises a range of colors. In certain embodiments, each wavelength range comprises two or more colors. In some embodiments, the first, second, and third wavelength ranges correspond to red, green, and blue, while in other embodiments, the first, second, and third colors correspond to deep blue, deep red, and yellow. Certain such embodiments advantageously provide for measurement of the intensity of each spectral component. Other wavelength ranges are also compatible with the embodiments described herein.

By utilizing interferometric elements 700 that are absorptive to different wavelength ranges, certain embodiments provide a light sensor that can distinguish between different wavelengths. For example, by making the interferometric element 700 shown in FIG. 8 absorptive to red, blue, and green, a light imaging sensor can be configured. Each pixel of the light imaging sensor is composed of an interferometric element 700 that measures the intensity of the red, green, and blue light according to a corresponding temperature change. Much like a CCD, the color is detected according to different temperature rises corresponding to the three primary colors (i.e., red, blue, and green). Some such embodiments may be used for image capture, while some other embodiments may be used to monitor the brightness of ambient light. In some embodiments, the detected brightness of ambient light may be advantageously used to set the amount of front or back light illuminating a display device to make the display device more readable in ambient light.

In some embodiments, a CCD camera uses an array of interferometric elements 700 having a temperature sensor 708 instead of a piece of silicon to receive incoming light. Each interferometric element detects input light as described with reference to fig. 6-10. The camera may also include a display for displaying the detected images. Additionally, in one embodiment, a display may comprise a CCD camera as described above. Light is shined onto the interferometric sensor until the light disappears. When the light source dies out (e.g., the shutter is closed), simple electronic circuitry and a microprocessor or computer are used to unload the interferometric sensors, measure the voltage change in each sensor, and process the resulting data into an image on a video monitor or other output medium.

FIG. 9 schematically shows a plurality of interferometric elements 700 comprising a set of three interferometric elements 700. Each interferometric element 700 has approximately the same pitch d₀Such that the interferometric element 700 is absorptive to the same at least one wavelength. A first set 900 of interferometric elements 700 has a first temperature sensor 708a, which temperature sensor 708a is responsive to a first temperature range associated with a certain ambient or incident light intensity. A second set 902 of interferometric elements 700 has a second temperature sensor 708b, which temperature sensor 708b is responsive to a second temperature range associated with a range of ambient or incident light intensities. A third set 904 of interferometric elements 700 has a third temperature sensor 708c, which temperature sensor 708c is responsive to a third temperature range associated with a range of ambient or incident light intensities. In certain embodiments, one or more of the first temperature range, the second temperature range, and the third temperature range overlap one another.

With the interferometric element 700 being responsive to different temperature ranges, certain embodiments advantageously provide a more accurate determination of the intensity of at least one wavelength of light absorbed by the interferometric element 700 than is possible with the temperature sensor 708 being responsive to a single temperature range. For example, in some embodiments, the first temperature sensor 708a is at a first temperature T₁A binary device that transitions between two states, the second temperature sensor 708b being one above T₁Second temperature T₂A binary device that transitions between two states, the third temperature sensor 708c being one above T₂Third temperature ofT₃A binary device that transitions between two states. By detecting the states of the three temperature sensors 708a, 20b, 20c, certain embodiments may determine that the temperature of the interferometric element 700 is below T₁Between T₁And T₂Between T₂And T₃Is also higher than T₃. In certain embodiments, a single interferometric element 700 includes more than one temperature sensor 708 to provide similar performance.

Certain embodiments have interferometric elements 700 that provide the ability to individually address and transition selected interferometric elements 700 between at least two states having different reflective and transmissive characteristics. In some such embodiments, an interferometric element 700 can be switched between two or more states to change the range of wavelengths absorbed by the interferometric element 700. Certain embodiments thereby advantageously provide the ability to arbitrarily modify the response of the interferometric element 700.

FIGS. 10A and 10B schematically show an exemplary embodiment of a photosensor comprising an array of interferometric elements 1002 and an array of color filters 1004. Each interferometric element 1002 is substantially reflective at least one wavelength and at least partially absorptive at other wavelengths. In the embodiment schematically illustrated in FIGS. 10A and 10B, each interferometric element 1002 has the same pitch d₀Such that each interferometric element 1002 absorbs the same at least one wavelength as the other interferometric elements 1002.

Each color filter 1004 is positioned such that light reflected from a corresponding interferometric element 1002 propagates through the color filter 1004. In the embodiment schematically illustrated in FIG. 10A, the color filters 1004 are positioned outside an outer surface 1006 of a substrate 1008 of the light sensor 1000. In the embodiment schematically shown in FIG. 10B, the color filters 1004 are positioned within the outer surface 1006 and are integral with the array of interferometric elements 1002.

Each color filter 1004 has a characteristic transmission spectrum in which a selected range of wavelengths is substantially transmitted through the color filter 1004 while other wavelengths are substantially not transmitted (e.g., reflected or absorbed) by the color filter 1004. In some embodiments, the array of color filters 1004 includes three subsets of color filters 1004. Each color filter 1004 in the first subset has a first transmission spectrum, each color filter 1004 in the second subset has a second transmission spectrum, and each color filter 1004 in the third subset has a third transmission spectrum. In some embodiments, the first, second, and third subsets of color filters 1004 have transmission spectra corresponding to substantially red, green, and blue light transmittance, respectively. In certain other embodiments, the first, second, and third subsets of color filters 1004 have transmission spectra corresponding to light transmittance of substantially deep blue, deep red, and yellow, respectively. Other color filters 1004 having other transmission spectra are also compatible with the embodiments described herein.

FIG. 11 is a graph showing the transmittance (T) as a function of wavelength (λ) for a set including three exemplary color filter materials compatible with embodiments described herein. The exemplary color filter material in FIG. 11 is a colored photosensitive color filter resin available from Brewer Science Specialty Materials, Inc. in Rolla, Missouri. The solid line in fig. 11 corresponds to the transmission spectrum of a PSCBlue * film having a thickness of 1.2 microns, the dashed line in fig. 11 corresponds to the transmission spectrum of a PSCGreen * film having a thickness of 1.5 microns, and the dotted line in fig. 11 corresponds to the transmission spectrum of a pscrid * film having a thickness of 1.5 microns.

12A-12C are three graphs showing the superposition of the transmission spectrum of the color filter material of FIG. 11 and the emission spectrum of a backlight. The convolution of the transmission spectra of each color filter material selects a corresponding portion of the emission spectrum of the backlight. The bandpass characteristics of the transmission spectrum of each color filter 1004 allows the interferometric elements 1002 to be used as separate color components for the pixels of the light sensor 1000.

The thickness of the pigment-based color filter material is selected to provide the desired transmission. Other color filter materials compatible with embodiments described herein include, but are not limited to, interference-based multi-layer dielectric structures.

By combining color filters 1004 corresponding to three colors (e.g., red/green/blue or dark blue/dark red/yellow) with interferometric elements 1002 having substantially equal spacing, certain such embodiments advantageously provide sensitivity to three color lines without patterning the structure of the interferometric elements 1002.

In some embodiments, the color filters 1004 are combined with two or more sets of interferometric elements 1002 having different pitches. Each set of interferometric elements 1002 absorbs a different range of wavelengths. In some embodiments, the color filters 1004 are used to modify the absorption spectrum of the interferometric element/color filter combination (e.g., by narrowing the range of wavelengths that reach the interferometric element 1002).

FIG. 13 is a system block diagram illustrating one embodiment of an electronic device 1302 including an interferometric element 700 having a temperature sensor for a side light source 1300. The interferometric element 700 may or may not be switchable. The interferometric element 700 absorbs light having at least one wavelength. The at least one wavelength is dependent on the separation d₀(see fig. 7). In the embodiment schematically illustrated in FIG. 13, light enters the interferometric element 700 perpendicular to the plane of the figure and reflects between the first surface 702 and the second surface 704 (see FIG. 7). At least a portion of the light having the at least one wavelength incident on the interferometric element 700 is absorbed by the interferometric element 700. The energy associated with the absorbed light is dissipated in the form of heat. The temperature sensor 708 is responsive to a change in temperature of at least a portion of the interferometric element 700 due to absorption of light. The temperature sensor 708 can detect a change in temperature of the portion of the interferometric element 700 by radiation, convection, conduction, or a combination of one or more physical processes that transfer thermal energy. The detected temperature change is received by the sidelight source 1300. The sidelight source 1300 uses the detected characteristics to control an optical compensation structure. In the exemplary embodiment shown in fig. 13, the optical compensation structure is a side light. In some embodiments, the intensity of the detected ambient light is measuredThe degree or brightness is used to set or adjust the amount of light illuminating the display electronics to make the display device easier to read in ambient light.

FIG. 14 is a system block diagram illustrating one embodiment of an electronic device 1400 including an interferometric element 700 having a temperature sensor for a backlight 1402. The electronic device 1400 shown in fig. 14 is a liquid crystal display. The interferometric element 700 may or may not be switchable. The interferometric element 700 absorbs light having at least one wavelength. The at least one wavelength is dependent on the separation d₀(see fig. 7). In the embodiment schematically illustrated in FIG. 14, light enters the interferometric element 700 substantially parallel to arrow 1404 and is reflected between the first surface 702 and the second surface 704 (see FIG. 7). At least a portion of the light having the at least one wavelength incident on the interferometric element 700 is absorbed by the interferometric element 700. The energy associated with this absorbed light is dissipated in the form of heat. The temperature sensor 708 is responsive to a change in temperature of at least a portion of the interferometric element 700 due to absorption of light. The temperature sensor 708 may detect a change in temperature of the portion of the interferometric element 700 by radiation, convection, conduction, or a combination of one or more physical methods of transferring thermal energy. The detected temperature change is received by the backlight 1402. The backlight 1402 uses the detected characteristics to control an optical compensation structure. In the exemplary embodiment shown in fig. 14, the optical compensation structure is a backlight. In some embodiments, the detected intensity or brightness of ambient light is used to set or adjust the amount of light illuminating the LCD display electronics to make the display device more readable in ambient light.

FIG. 15 shows an exemplary series of steps for detecting light using an electronic device having an embodiment of the interferometric element 700 and temperature sensor 708 described above. The process begins at state 1500 where an interferometric element 700 having a temperature sensor 708 absorbs light of at least one wavelength. In certain embodiments, the interferometric element 700 comprises a first surface 702 and a second surface substantially parallel to the first surface 702A second surface 704. The second surface 704 is spaced apart from the first surface 702 by a distance d in a direction substantially perpendicular to the first surface 702₀. The first surface 702 is partially transmissive and partially reflective to the at least one wavelength. The second surface 704 is at least partially reflective to light. Exemplary materials for first surface 702 and second surface 704 include, but are not limited to, chromium or titanium.

The first surface 702 and the second surface 704 form a resonant cavity (e.g., etalon) in which light interferes with itself by reflecting between the first surface 702 and the second surface 704. The interferometric element 700 absorbs light having at least one wavelength. The energy associated with the light absorbed in the first surface 702 is dissipated in the form of heat. In various embodiments, as schematically illustrated in FIG. 7, the first surface 702 is located on a substrate 706. In other embodiments, the interferometric element 700 comprises one or more layers (e.g., dielectric layers) on the first surface 702, such that the first surface 702 is between the layers and the substrate 706.

The dimensions of the interferometric element 700 vary according to the micro-fabrication design rules. In semiconductor fabrication, certain embodiments can be realized in which the area of the interferometric element 700 is less than or equal to about one square micron. Certain other embodiments provide an interferometric element 700 having an area less than or equal to about 0.5 square microns. Other dimensions of the interferometric element 700 may also be compatible with the embodiments described herein.

Then, in state 1502, the temperature sensor 708 detects a change in temperature of at least a portion of the interferometric element 700. The temperature sensor 708 may be responsive to a change in temperature of at least a portion of the interferometric element 700 due to absorption of light by the interferometric element 700. In the embodiment schematically shown in fig. 7, the temperature sensor 708 is located on the first surface 702 and between the first surface 702 and the second surface 704. Other locations for the temperature sensor 708 are also compatible with the embodiments described herein. In certain embodiments, the temperature sensor 708 is located adjacent to or separate from the first surface 702. In these embodiments, the temperature sensor 708 may detect a change in temperature of the portion of the first surface 702 by radiation, convection, conduction, or a combination of one or more physical processes that transfer thermal energy. In the exemplary embodiment shown in fig. 6A, 6B, and 6C, the temperature sensor 708 may be located near or adjacent to an optical stack. In certain embodiments, the optical stack includes a fixed layer 16a, 16b and a layer adjacent to the fixed layer. These adjoining layers may include a dielectric layer, a chromium layer, an indium tin oxide layer, and a transparent substrate 20.

In certain embodiments, the absorption and corresponding heat varies with wavelength. For example, the interferometric element 700 may have different absorption coefficients for red, green, and blue light, thereby generating different amounts of heat for these different wavelengths of incident light. In certain embodiments, the material of the interferometric element 700 is selected to have sensitivity to a selected range of wavelengths. Ranges of wavelengths that are detectable by the interferometric elements 700 that are compatible with the embodiments described herein include, but are not limited to, visible wavelengths, infrared and ultraviolet wavelengths, Radio Frequency (RF) wavelengths, and X-ray wavelengths.

For example, the temperature sensor 708 may be a contact or non-contact sensor. Exemplary contact temperature sensors that may be used with the embodiments described herein include thermocouples, thermistors, Resistance Temperature Detectors (RTDs), fill system thermometers, bimetallic thermometers, and semiconductor temperature sensors. For example, a bimetal thermocouple may be used to generate a voltage difference as a function of temperature. Example non-contact temperature sensors that may be used with the embodiments described herein include radiation thermometers (e.g., pyrometers), thermal imagers, proportional thermometers, optical pyrometers, and fiber optic temperature sensors. Other temperature sensors 708 are also compatible with the embodiments described herein.

By absorbing light having at least one wavelength, the temperature of the interferometric element 700 increases, and the temperature sensor 708 responds to this increase in temperature. In certain embodiments, the response of temperature sensor 708 is determined by measuring a change in voltage of temperature sensor 708. For example, V₀And V₁The voltage change therebetween corresponds to a temperature change of the portion of the first surface 702. In certain embodiments, the increase in temperature is dependent on the intensity of the at least one wavelength of light absorbed by the interferometric element 700.

Proceeding to state 704, data indicative of the detected temperature change is provided to the electronic device. Embodiments of the electronic device include a camera or a fingerprint sensor. In some embodiments, the change in temperature is processed and stored as a digital image. In certain other embodiments, the change in temperature is used to set the amount of front light and back light that illuminate the display device to make the display device more readable in ambient light.

16A and 16B are system block diagrams illustrating one embodiment of a display device 2040. The display device 2040 can be, for example, a cellular or mobile telephone. However, the same components of display device 2040 and slight variations thereof are also illustrative of various types of display devices such as televisions and portable media players.

The display device 2040 includes a housing 2041, a display 2030, an antenna 2043, a speaker 2045, an input device 2048, and a microphone 2046. The housing 2041 is typically made by any of a number of manufacturing processes well known to those skilled in the art, including injection molding and vacuum forming. Further, the housing 2041 may be made from any of a wide variety of materials, including but not limited to plastic, metal, glass, rubber, and ceramic, or a combination thereof. In one embodiment, the housing 2041 includes removable portions (not shown) that can be interchanged with other removable portions of different color, or containing different logos, pictures, or symbols.

The display 2030 of exemplary display device 2040 may be any of a wide variety of displays, including a bi-stable display as described herein. In other embodiments, the display 2030 includes a flat panel display, such as a plasma display, EL, OLED, STN LCD, or TFT LCD as described above, or a non-flat panel display, such as a CRT or other tube device, as is well known to those of skill in the art. However, for purposes of describing the present embodiment, the display 2030 includes an interferometric modulator display, as described herein.

FIG. 16B schematically shows components in an embodiment of an exemplary display device 2040. The exemplary display device 2040 shown includes a housing 2041 and may include other components at least partially enclosed therein. For example, in one embodiment, the exemplary display device 2040 includes a network interface 2027, the network interface 2027 including an antenna 2043 coupled to a transceiver 2047. The transceiver 2047 is connected to the processor 2021, which processor 2021 is in turn connected to conditioning hardware 2052. Conditioning hardware 2052 may be configured to condition (e.g., filter) a signal. Conditioning hardware 2052 is coupled to a speaker 2045 and a microphone 2046. The processor 2021 is also connected to an input device 2048 and a driver controller 2029. The driver controller 2029 is coupled to a frame buffer 2028 and to the array driver 2022, which in turn is coupled to a display array 2030. A power supply 2050 provides power to all components as required by the design of the particular exemplary display device 2040.

The network interface 2027 includes the antenna 2043 and the transceiver 2047 so that the exemplary display device 2040 can communicate with one or more devices over a network. In one embodiment, the network interface 2027 may also have some processing functions to reduce the requirements on the processor 2021. The antenna 2043 is any antenna known to those skilled in the art for transmitting and receiving signals. In one embodiment, the antenna transmits and receives RF signals according to the IEEE 802.11 standard, including IEEE 802.11(a), (b), or (g). In another embodiment, the antenna transmits and receives RF signals according to the Bluetooth (BLUETOOTH) standard. In the case of a cellular telephone, the antenna is designed to receive CDMA, GSM, AMPS or other conventional signals used to communicate in a wireless mobile telephone network. The transceiver 2047 pre-processes the signals received from the antenna 2043 so that they may be received by and further processed by the processor 2021. The transceiver 2047 also processes signals received from the processor 2021 so that they may be transmitted from the exemplary display device 2040 via the antenna 2043.

In an alternative embodiment, the transceiver 2047 may be replaced by a receiver. In yet another alternative embodiment, the network interface 2027 can be replaced by an image source, which can store or generate image data to be sent to the processor 2021. For example, the image source can be a Digital Video Disc (DVD) or a hard-disc drive that contains image data, or a software module that generates image data.

The processor 2021 generally controls the overall operation of the exemplary display device 2040. The processor 2021 receives data, such as compressed image data, from the network interface 2027 or an image source and processes the data into raw image data or into a format that is readily processed into raw image data. The processor 2021 then sends the processed data to the driver controller 2029 or to frame buffer 2028 for storage. Raw data generally refers to information that can identify the image characteristics at each location within an image. For example, the image characteristics may include color, saturation, and gray-scale level.

In one embodiment, the processor 2021 includes a microcontroller, CPU, or logic unit to control operation of the exemplary display device 2040. Conditioning hardware 2052 typically includes amplifiers and filters for sending signals to the speaker 2045, and for receiving signals from the microphone 2046. Conditioning hardware 2052 may be discrete components within the exemplary display device 2040 or may be incorporated within the processor 2021 or other components.

The driver controller 2029 receives raw image data generated by the processor 2021 either directly from the processor 2021 or from the frame buffer 2028 and reformats the raw image data appropriately for high speed transmission to the array driver 2022. In particular, the driver controller 2029 reformats the raw image data into a data flow having a raster-like format, such that it has a time order suitable for scanning the display array 2030. The driver controller 2029 then sends the formatted information to the array driver 2022. Although a driver controller 2029, such as an LCD controller, is typically associated with the system processor 2021 as a stand-alone Integrated Circuit (IC), such controllers may be implemented in a number of ways. They may be embedded in the processor 2021 as hardware, embedded in the processor 2021 as software, or fully integrated in hardware with the array driver 2022.

Typically, the array driver 2022 receives the formatted information from the driver controller 2029 and reformats the video data into a parallel set of waveforms that are applied many times per second to the hundreds and sometimes thousands of leads coming from the display's x-y matrix of pixels.

In one embodiment, the driver controller 2029, array driver 2022, and display array 2030 are appropriate for any of the types of displays described herein. For example, in one embodiment, the driver controller 2029 is a conventional display controller or a bi-stable display controller (e.g., an interferometric modulator controller). In another embodiment, the array driver 2022 is a conventional driver or a bi-stable display driver (e.g., an interferometric modulator display). In one embodiment, a driver controller 2029 is integrated with the array driver 2022. Such embodiments are common in highly integrated systems such as cellular phones, watches, and other small area displays. In yet another embodiment, the display array 2030 is a typical display array or a bi-stable display array (e.g., a display including an array of interferometric modulators).

The input device 2048 enables a user to control the operation of the exemplary display device 2040. In one embodiment, input device 2048 includes a keypad (e.g., a QWERTY keyboard or a telephone keypad), a button, a switch, a touch-sensitive screen, a pressure-or heat-sensitive membrane. In one embodiment, the microphone 2046 is an input device for the exemplary display device 2040. When the microphone 2046 is used to input data to the device, voice commands may be provided by a user to control operation of the exemplary display device 2040.

The power supply 2050 can include a variety of energy storage devices, as are well known in the art. For example, in one embodiment, power supply 2050 is a rechargeable battery, such as a nickel-cadmium battery or a lithium ion battery. In another embodiment, power supply 2050 is a renewable energy source, a capacitor, or a solar cell, including plastic solar cells and solar-cell paint. In another embodiment, power supply 2050 is configured to receive power from a wall outlet.

In some implementations control programmability resides, as described above, in a driver controller, which can be located in several places in the electronic display system. In some cases, control programmability exists in the array driver 2022. Those skilled in the art will appreciate that the above-described optimization may be implemented in any number of hardware and/or software components and in various configurations.

While the above detailed description has shown, described, and pointed out novel features of the invention as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the spirit of the invention. Methods of combining the above-described devices with interferometric modulators will be readily apparent to those of ordinary skill in the art. In addition, one or more of such devices may be modified for use with any of the embodiments and other interferometric modulator configurations. It will be recognized that the present invention may be embodied within a form that does not provide all of the features and benefits set forth herein, as some features may be used or practiced separately from others.

Claims

1. A light sensor having at least one interferometric modulator, the interferometric modulator comprising:

a first surface that is partially transmissive and partially reflective to at least one wavelength of light;

a second surface substantially parallel to and spaced a first distance from the first surface to reflect at least a portion of the at least one wavelength of light; and

a temperature sensor coupled to the first surface and responsive to a change in temperature of at least a portion of the first surface, the change in temperature being caused at least in part by absorption of the at least one wavelength of light.

2. The light sensor of claim 1, wherein the temperature sensor comprises a binary device.

3. The light sensor of claim 2, wherein the binary device is in a first state when the temperature is below a predetermined level and in a second state when the temperature is above a predetermined level.

4. The light sensor of claim 3, wherein the binary device is formed using micro-electromechanical systems (MEMS) fabrication techniques.

5. The light sensor of claim 1, wherein the temperature sensor comprises an analog device.

6. The light sensor of claim 5, wherein the analog device comprises a bimetallic thermocouple.

7. The light sensor of claim 5, wherein the analog device generates a voltage difference as a function of temperature.

8. The light sensor of claim 1, further comprising a second interferometric modulator, the second interferometric modulator comprising:

a third surface that is partially transmissive and partially reflective to light of at least a second wavelength;

a fourth surface substantially parallel to and spaced a second distance from the third surface to reflect at least a portion of the at least one wavelength of light; and

a second temperature sensor coupled to the third surface and responsive to a change in temperature of at least a portion of the third surface due to absorption of light at the at least one second wavelength.

9. The light sensor of claim 8, wherein the second temperature sensor comprises a second binary device.

10. The light sensor of claim 9, wherein the second binary device is in a first state when temperature is below a predetermined level and in a second state when temperature is above a predetermined level.

11. The light sensor of claim 10, wherein the second binary device is formed using micro-electromechanical systems (MEMS) fabrication techniques.

12. The light sensor of claim 8, wherein the second temperature sensor comprises a second analog device.

13. The light sensor of claim 12, wherein the second analog device comprises a bimetallic thermocouple.

14. The light sensor of claim 12, wherein said second analog means generates a voltage difference as a function of temperature.

15. The light sensor of claim 1, further comprising a second interferometric modulator, the second interferometric modulator comprising:

a third surface that is partially transmissive and partially reflective to the at least one wavelength of light;

a fourth surface substantially parallel to and spaced a first distance from the third surface to reflect at least a portion of the at least one wavelength of light; and

a second temperature sensor coupled to the third surface and responsive to a change in temperature of at least a portion of the third surface due to absorption of the at least one wavelength of light, wherein an activation temperature of the second temperature sensor is different from an activation temperature of the temperature sensor.

16. The light sensor of claim 1, further comprising a substrate coupled to the temperature sensor.

17. A method for detecting light, comprising:

providing a first surface that is partially transmissive and partially reflective to at least one wavelength of light;

providing a second surface substantially parallel to and spaced a distance from the first surface to reflect at least a portion of the at least one wavelength of light;

absorbing light of the at least one wavelength on the first surface; and

detecting a change in temperature of at least a portion of the first surface.

18. A camera having a light sensor, the camera comprising:

a housing; and

an interferometric modulator located within the housing, the interferometric modulator comprising:

a first surface that is partially transmissive and partially reflective to at least one wavelength of light,

a second surface substantially parallel to and spaced a first distance from the first surface to reflect at least a portion of the at least one wavelength of light, an

19. The camera as in claim 18, wherein the temperature sensor comprises a binary device.

20. The camera of claim 18, wherein the temperature sensor comprises an analog device.

21. The camera of claim 18, wherein the change in temperature is at least partially indicative of a wavelength of the at least one wavelength of light.

22. The camera of claim 18, wherein the change in temperature is indicative, at least in part, of an intensity associated with the at least one wavelength of light.

23. A display device having a light sensor, the display device comprising:

a housing; and

24. The display device of claim 23, further comprising:

a display;

a processor in electrical communication with the display, the processor configured to process image data;

a memory device in electrical communication with the processor.

25. The display device of claim 24, further comprising:

a drive circuit configured to send at least one signal to the display.

26. The display device of claim 25, further comprising:

a controller configured to send at least a portion of the image data to the drive circuit.

27. The display device of claim 24, further comprising:

an image source module configured to send the image data to the processor.

28. The display device of claim 24, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

29. The display device of claim 24, further comprising:

an input device configured to receive input data and to communicate the input data to the processor.

30. The display device of claim 23, wherein the change in temperature is at least partially indicative of a wavelength of the at least one wavelength of light.

31. The display device of claim 23, wherein the change in temperature is indicative, at least in part, of an intensity associated with the at least one wavelength of light.

32. A method of manufacturing a light sensor having at least one interferometric modulator, the method comprising:

forming a first surface that is partially transmissive and partially reflective to at least one wavelength of light;

forming a second surface substantially parallel to and spaced a first distance from the first surface to reflect at least a portion of the at least one wavelength of light; and

forming a temperature sensor coupled to the first surface and responsive to a change in temperature of at least a portion of the first surface caused at least in part by absorption of the at least one wavelength of light.

33. The method of claim 32, wherein the temperature sensor is in a first state when the temperature is below a predetermined level and in a second state when the temperature is above a predetermined level.

34. The method of claim 32, wherein the temperature sensor comprises a thermocouple.

35. The method of claim 32, further comprising:

forming a third surface that is partially transmissive and partially reflective to at least a second wavelength of light;

forming a fourth surface substantially parallel to and spaced a second distance from the third surface to reflect at least a portion of the at least one wavelength of light; and

forming a second temperature sensor coupled to the third surface and responsive to a change in temperature of at least a portion of the third surface due to absorption of light at the at least one second wavelength;

wherein the third and fourth surfaces and the second temperature sensor comprise a second interferometric modulator.

36. A light sensor made by a process, the process comprising:

37. The light sensor of claim 36, wherein the process further comprises forming the temperature sensor such that the temperature sensor is in a first state when the temperature is below a predetermined level and in a second state when the temperature is above a predetermined level.

38. The light sensor of claim 36, wherein the process further comprises forming the temperature sensor such that the temperature sensor comprises a thermocouple.

39. The light sensor of claim 36, wherein the process further comprises:

40. A light sensor having at least one interferometric modulator, the interferometric modulator comprising:

means for partially transmitting and partially reflecting light of at least one wavelength;

means for reflecting at least a portion of the at least one wavelength of light coupled to the means for partially transmitting and partially reflecting; and

means for detecting a change in temperature of and coupled to the means for partially transmitting and partially reflecting the at least one wavelength of light caused at least in part by absorption of the at least one wavelength of light.

41. The light sensor of claim 40, further comprising:

a second means for partially transmitting and partially reflecting at least one wavelength of light coupled to the means for partially transmitting and partially reflecting;

a second means for reflecting at least a portion of the at least one wavelength of light coupled to the means for reflecting; and

a second means for detecting a change in temperature of the means for partially transmitting and partially reflecting the at least one wavelength of light and coupled to the means, the change in temperature being caused at least in part by absorption of the at least one wavelength of light.

42. The light sensor of claim 41, wherein the first means for detecting a change in temperature has an activation temperature that is different from an activation temperature of the second means for detecting a change in temperature.