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WO2019031355A1 - Unité de rétroéclairage et dispositif électronique - Google Patents

Unité de rétroéclairage et dispositif électronique Download PDF

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Publication number
WO2019031355A1
WO2019031355A1 PCT/JP2018/028877 JP2018028877W WO2019031355A1 WO 2019031355 A1 WO2019031355 A1 WO 2019031355A1 JP 2018028877 W JP2018028877 W JP 2018028877W WO 2019031355 A1 WO2019031355 A1 WO 2019031355A1
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WO
WIPO (PCT)
Prior art keywords
constant current
led
backlight unit
circuit
voltage generation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2018/028877
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English (en)
Japanese (ja)
Inventor
齊藤　浩二
森　泰樹
正樹 植畑
和也 近藤
一久 吉本
晃祐 川本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
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Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Publication of WO2019031355A1 publication Critical patent/WO2019031355A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21S—NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS
    • F21S2/00—Systems of lighting devices, not provided for in main groups F21S4/00 - F21S10/00 or F21S19/00, e.g. of modular construction
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V19/00—Fastening of light sources or lamp holders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/502—Cooling arrangements characterised by the adaptation for cooling of specific components
    • F21V29/503—Cooling arrangements characterised by the adaptation for cooling of specific components of light sources
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/502—Cooling arrangements characterised by the adaptation for cooling of specific components
    • F21V29/508—Cooling arrangements characterised by the adaptation for cooling of specific components of electrical circuits
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V29/00—Protecting lighting devices from thermal damage; Cooling or heating arrangements specially adapted for lighting devices or systems
    • F21V29/50—Cooling arrangements
    • F21V29/70—Cooling arrangements characterised by passive heat-dissipating elements, e.g. heat-sinks
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods

Definitions

  • the present invention relates to a backlight unit and an electronic device.
  • a liquid crystal module (LCM: Liquid Crystal Module) 204 of a conventional laptop PC (Personal Computer: personal computer) 201 includes a backlight unit 202, a display control substrate 203, and a liquid crystal panel (not shown). including.
  • a plurality of LEDs 210, a flexible printed circuit (FPC) 207 on which a plurality of LEDs 210 are mounted, and a light guide plate 206 are stored in a bezel 205.
  • the display control board 203 includes a plurality of LED driver ICs (Integrated Circuits) 240, a power supply IC 251, a Tcon (Timing Controller: Timing Controller) 252, and an EEPROM (Electrically Erasable Programmable Read-Only Memory: A non-volatile memory 253 such as a trademark) and an input connector 254 are provided.
  • the light emitted from the plurality of LEDs 210 enters the light guide plate 206 from one side surface of the light guide plate 206, emits from the main surface of the light guide plate 206 out of the light guide plate 206, and illuminates a liquid crystal panel (not shown).
  • the backlight unit 202 has three LED arrays 212.
  • an LED string 211 is configured by connecting eight LEDs 210 in series, and four LED strings 211 are configured in parallel.
  • the LED driver IC 240 is provided in one-to-one correspondence with the LED array 212.
  • the LED driver IC 240 includes, in the LED array 212, the channels ch201 to ch204 to which the cathodes of the LED rows 211 are connected, the constant current circuit 220 for supplying a constant current to each LED row 211, and the anodes of the LED rows 211. And a booster circuit 230 for generating a voltage to be supplied.
  • the LED driver IC 240 is connected between the coil 232 and the anode of the diode 231, and the cathode of the diode 231 is connected to the anode of each LED row 211.
  • the boosting circuit 230 of the LED driver IC 240, the coil 232, and the diode 231 constitute a boosting circuit block 233 that supplies a boosted voltage to the anode of each LED string 211.
  • the backlight unit 202 needs to be a direct light type, not a side light type.
  • Patent Document 1 discloses a direct type backlight unit.
  • the direct type backlight unit has more LEDs.
  • the number of LED driver ICs 240 provided corresponding to the LED arrays 212 and in which the constant current circuit 220 and the booster circuit 230 are integrated also increases.
  • the area of the display control board 203 shown in FIG. 17 also needs to be increased.
  • the Y dimension Y200 of the liquid crystal module which is the length to the opposite side) also becomes large.
  • An object of one embodiment of the present invention is to obtain a direct-type backlight unit while suppressing an increase in size of a display control substrate.
  • a back light unit concerning one mode of the present invention is a direct-back type back light unit, and a substrate and a plurality of LED arranged on the above-mentioned substrate were connected Or a plurality of LED arrays, and one or more constant current ICs provided on the base material corresponding to the LED arrays and supplying constant current to the LEDs included in the LED arrays, the LED array comprising A plurality of LED strings including a plurality of LEDs connected in series, and the constant current IC includes a plurality of constant current circuits connected to each of the plurality of LED strings.
  • FIG. 2 is a cross-sectional view illustrating the configuration of the electronic device according to the first embodiment.
  • FIG. 2 is a plan view illustrating a configuration of a liquid crystal module of Embodiment 1.
  • FIG. 6 is a plan view illustrating a configuration of a backlight unit and a display control board in the electronic device of Embodiment 1.
  • FIG. 2 is a diagram illustrating a circuit of a backlight unit and a voltage generation circuit block in the electronic device of Embodiment 1.
  • FIG. 2 is a diagram illustrating a configuration of a constant current IC of Embodiment 1.
  • FIG. 7 is a diagram illustrating a configuration in which a voltage generation IC is provided on a main control substrate in the electronic device of Embodiment 1.
  • FIG. 7 is a diagram illustrating a configuration of an electronic device of a second embodiment.
  • FIG. 7 is a diagram illustrating a configuration of an electronic device of a third embodiment.
  • FIG. 7 is a circuit diagram of a backlight unit and an LED driver according to a first comparative example. It is a figure showing the composition of the electronic equipment of the 2nd comparative example. It is a figure showing the composition of the liquid crystal module of the conventional notebook PC. It is a circuit diagram of a backlight unit and an LED driver in a conventional notebook PC.
  • FIG. 6 is a diagram for explaining the operation of the voltage generation circuit block of the first embodiment. It is a figure showing the voltage in the voltage generation circuit block of FIG. It is sectional drawing showing the structure of the liquid crystal module for televisions.
  • first comparative example and the second comparative example As in the conventional side light type backlight module shown in FIGS. 17 and 18, a constant current circuit and a booster circuit are integrally provided for each LED array. It is a liquid crystal module having a direct type backlight module provided with an LED driver IC.
  • FIG. 14 is a diagram illustrating the configuration of the electronic device 101 of the first comparative example.
  • the liquid crystal module 104 of the electronic device 101 such as a notebook PC includes a backlight unit 102, a display control substrate 103, and a liquid crystal panel (not shown).
  • a bezel 105 stores a plurality of LEDs 110, a base material 107 such as an FPC on which the plurality of LEDs 110 are mounted, and a diffusion plate 106.
  • the plurality of LEDs 110 are provided in a matrix on the base material 107, and a diffusion plate 106 is provided to cover the plurality of LEDs 110.
  • the display control board 103 is provided with a plurality of LED driver ICs 140, a power source IC 151, a Tcon 152, a nonvolatile memory 153 such as an EEPROM, an input connector 154 and the like.
  • the light emitted from the plurality of LEDs 110 enters the diffusion plate 106 from the back surface of the diffusion plate 106, exits from the main surface of the diffusion plate 106 to the outside of the diffusion plate 106, and illuminates a liquid crystal panel (not shown).
  • FIG. 15 is a circuit diagram of a backlight unit and an LED driver according to a first comparative example.
  • the backlight unit 102 has eight LED arrays 112.
  • an LED string 111 is configured by connecting four LEDs 110 in series, and sixteen LED strings 111 are configured in parallel.
  • the LED driver IC 140 is provided in one-to-one correspondence with the LED array 112. That is, eight LED driver ICs 140 are also provided.
  • the LED driver IC 140 includes the channels ch101 to ch116 to which the cathode of each LED array 111 is connected in the LED array 112, the constant current circuit 120 for supplying a constant current to each LED array 111, and the anode of each LED array 111. And a booster circuit 130 for generating a voltage to be supplied.
  • the LED driver IC 140 is connected between the coil 132 and the anode of the diode 131, and the cathode of the diode 131 is connected to the anode of each LED string 111.
  • the boosting circuit 130 of the LED driver IC 140, the coil 132, and the diode 131 constitute a boosting circuit block 133 that supplies a boosted voltage to the anode of each LED array 111.
  • the area of the display control board 103 needs to be greatly enlarged.
  • the lower side of the display control board 103 (the side facing the backlight unit 102) from the upper side of the backlight unit 102 (the side opposite to the side facing the display control board 103).
  • the Y dimension Y100 of the liquid crystal module which is the length to the side opposite to
  • FIG. 16 is a diagram illustrating the configuration of the electronic device 101A of the second comparative example.
  • the electronic device 101A is provided not on the display control substrate 103 but on the base 107 so as to be adjacent to one side surface of the diffusion plate 106 instead of providing the eight LED drivers 140.
  • the circuit configuration of the backlight unit and the LED driver of the electronic device 101A is the same as the circuit configuration of the backlight unit and the LED driver shown in FIG.
  • the lower side of the display control board 103 (the side facing the backlight unit 102) and the upper side of the backlight unit 102 (the side opposite to the side facing the display control board 103)
  • the Y dimension Y100A of the liquid crystal module which is the length to the opposite side) does not increase, and can be approximately the same as the Y dimension Y200 of the liquid crystal module shown in FIG.
  • the area of the backlight unit 102 is increased, or Alternatively, when provided on both the front and back sides of the base material 107, the thickness of the backlight unit 102 becomes thick.
  • the eight LED drivers 140 and the peripheral circuits including the eight coils 132 and the diodes 131 corresponding to them are not provided on both the front and back sides of the substrate 107
  • the peripheral circuit including the coil 132 and the diode 131 corresponding to a part of the LED driver 140 among the eight LED drivers 140 can not be provided on the base material 107, and must be provided on the display control substrate 103. .
  • the coil 132 and the diode 131 corresponding to a part of the LED driver 140 among the eight LED drivers 140 are provided on the display control board 103, and the coil 132 and the diode corresponding to the other part LED driver 140
  • the substrate 131 is provided on the substrate 7
  • the electrical characteristics between the LED drivers 140 change, and the luminance of each LED array 112 can not be controlled with high accuracy.
  • FIG. 1 is a cross-sectional view illustrating the configuration of the electronic device 1 according to the first embodiment.
  • the electronic device 1 is various electronic devices having a display area of an image.
  • the electronic device 1 may be a television, but is preferably a mobile electronic device such as a notebook PC, a tablet terminal, a mobile phone terminal or the like.
  • the electronic device 1 will be described as being a notebook PC.
  • the electronic device 1 includes a liquid crystal module 4, a main control substrate 9 which is a mother board, and a bezel 5 (see FIG. 2) for storing a backlight unit of the liquid crystal module 4.
  • the main control board 9 comprehensively controls the operation of the electronic device 1.
  • the main control board 9 is made of resin, metal or the like, and various circuits are provided.
  • the liquid crystal module 4 includes a liquid crystal panel 8, a backlight unit 2, and a display control substrate 3.
  • the backlight unit 2 is disposed on the back side of the liquid crystal panel 8 and illuminates the liquid crystal panel 8 from the back side.
  • the liquid crystal panel 8 is configured such that a TFT substrate provided with TFT elements (Thin Film Transistors) for each pixel and a counter substrate face each other with a liquid crystal layer interposed.
  • TFT elements Thin Film Transistors
  • the display control board 3 controls the driving of the backlight unit 2 and the liquid crystal panel 8 by outputting a drive signal to the backlight unit 2 and the liquid crystal panel 8 according to an instruction from the main control board 9.
  • the display control board 3 is made of resin, metal or the like, and various circuits are mounted.
  • FIG. 2 is a plan view showing the configuration of the liquid crystal module 4 of the first embodiment.
  • the liquid crystal panel 8 has a display area 81 in which pixels are arranged in a matrix and displays an image, and a frame area 4 a which is an area around the display area 81.
  • the frame area 4 a is an area from the edge of the display area 81 to the outermost edge of the backlight unit 2 or the liquid crystal panel 8.
  • the frame area 4 a refers to an area from the edge of the display area 81 to the edge of the bezel 5 (that is, the edge of the backlight unit 2).
  • an area above the display area 81 is referred to as an upper frame 4aT
  • an area below the display area 81 is referred to as a lower frame 4aD
  • an area to the right of the display area 81 is right
  • the area to the left of the display area 81 is referred to as a left frame 4aL.
  • a landscape type is generally adopted in liquid crystal modules for notebook PCs.
  • the mounting area of the source driver SD is secured in the lower frame 4aD of the liquid crystal module 4, and the display control substrate 3 is disposed outside the lower frame 4aD.
  • a region outside the display area 81 may be referred to as a panel frame. Further, which of the backlight unit 2 and the liquid crystal panel 8 is the outermost edge varies depending on the application of the liquid crystal module 4.
  • FIG. 3 is a plan view showing the configuration of the backlight unit 2 and the display control board 3 in the electronic device 1 of the first embodiment.
  • the liquid crystal panel 8 of the liquid crystal module 4 is not shown.
  • the backlight unit 2 is a direct type backlight unit, and can emit light by the local dimming method.
  • the backlight unit 2 includes a substrate 7, a plurality of LEDs 10 (light emitting elements) mounted on the substrate 7, a diffusion plate 6 provided on the plurality of LEDs 10, and a plurality of substrates mounted on the substrate 7. It includes a current IC and a bezel 5 that houses the base 7 and the diffusion plate 6.
  • the substrate 7 is, for example, an FPC.
  • the base 7 is not limited to the FPC, and may be a substrate or the like made of a material such as resin or metal.
  • the display control substrate 3 is electrically connected to the base 7, and outputs various signals to the backlight unit 2 and the liquid crystal panel 8 through the connection portion.
  • the display control board 3 is provided with a power supply IC 51, a Tcon 52, a non-volatile memory 53 such as an EEPROM, an input connector 54 and the like. Furthermore, the display control board 3 is provided with one or more voltage generation circuit blocks 33 for supplying a desired voltage to the LED 10.
  • the voltage generation circuit block 33 includes a voltage generation IC 30, a diode 31 and a coil 32.
  • the voltage generation IC 30 may include the function of the diode 31. In this case, the diode 31 is unnecessary.
  • FIG. 4 is a diagram showing a circuit of the backlight unit 2 and the voltage generation circuit block 33 in the electronic device 1 of the first embodiment.
  • the backlight unit 2 includes one or more LED arrays 12 and one or more constant current ICs 20 for supplying a constant current to the LEDs 10.
  • the LED array 12 is connected in series to one voltage generation circuit block 33.
  • a voltage generation IC 30 for generating a voltage to be supplied to the anode of the LED 10 is connected between the anode of the diode 31 and the coil 32.
  • the voltage generation IC 30 is provided on the display control substrate 3 which is a substrate different from the substrate 7 on which the constant current IC 20 is provided.
  • the voltage generation IC 30 includes a boost circuit, a step-down circuit or a step-up / step-down circuit for supplying a desired current to the LED 10.
  • each LED array 12 is configured by connecting in parallel a plurality of LED strings 11 connected in series.
  • the LED array 11 is configured by connecting four LEDs 10 in series
  • each LED array 12 is configured by connecting 16 LED arrays 11 in parallel.
  • eight LED arrays 12 are provided side by side.
  • the anodes of the LED arrays 11 are configured by connecting the anodes of the LED arrays 11 to each other.
  • the anode of each LED array 12 is connected to the cathode of the diode 31.
  • the constant current IC 20 is provided to the LED array 12 in a one-to-one correspondence.
  • eight LED arrays 12 are provided, so eight constant current ICs 20 are also provided.
  • FIG. 5 is a diagram illustrating the configuration of the constant current IC 20 according to the first embodiment.
  • the constant current IC 20 has a control signal input circuit 21, a constant current circuit block control circuit 22 (constant current control circuit), a plurality of constant current circuits C1 to C16, and a plurality of channels ch1 to ch16.
  • each LED row 11 is connected to each of the channels ch1 to ch16.
  • the constant current circuits C1 to C16 are provided corresponding to the channels ch1 to ch16 (in other words, corresponding to the respective LED columns 11). Constant current circuits C1 to C16 are connected to the channels ch1 to ch16, respectively. The constant current circuits C1 to C16 are circuits for causing a constant current to flow in each LED row 11.
  • the control signal input circuit 21 is an interface input circuit that receives an input of a control signal.
  • the control signal input circuit 21 obtains a control signal such as SCS, SCLK, or SDI from the control circuit provided on the display control board 3, the control signal input circuit 21 outputs an instruction signal to the constant current circuit block control circuit 22 based on the control signal. Do.
  • the constant current circuit block control circuit 22 individually controls the current supplied to each of the constant current circuits C1 to C16 based on the control signal acquired from the control signal input circuit 21. In other words, the current supplied to each LED row 11 is controlled for each LED row 11. In this way, local dimming can be performed to adjust the luminance for each of the LED rows 11.
  • the constant current IC 20 can be configured to access using, for example, an interface standard such as SPI (Serial Peripheral Interface).
  • SPI Serial Peripheral Interface
  • the interface standard for accessing the constant current IC 20 is arbitrary, and is not limited to SPI.
  • a voltage supplied to the anode of each LED array 11 according to the current flowing in the constant current circuits C1 to C16 (that is, the current flowing in each LED array 11) between each constant current IC 20 and the voltage generation IC 30 A control circuit may be provided which outputs a voltage adjustment signal for adjusting the voltage to the voltage generation IC 30.
  • the voltage generation IC 30 can adjust the voltage supplied to each of the LED rows 11 to increase the luminous efficiency of each LED 10.
  • FIG. 19 is a diagram for explaining the operation of the voltage generation circuit block 33.
  • FIG. 20 is a diagram showing voltages in the voltage generation circuit block 33 of FIG.
  • the voltage generation IC 30 of the voltage generation circuit block 33 is a boost IC.
  • the configuration and operation of the voltage circuit block 33 shown in FIGS. 19 and 20 are an example, and other aspects can be adopted.
  • the voltage generation circuit block 33 further includes a first capacitance Cin on the input side disposed upstream of the coil 32 and a second capacitance Cout on the output side connected to the cathode of the diode 31.
  • the voltage generation IC 30 has a switch 30 a connected between the coil 32 and the diode 31.
  • the voltage on the input side of the voltage generation circuit block 33 is a voltage vin
  • the voltage on the output side (the side connected to the backlight unit 2) is a voltage Vout.
  • FIG. 6 is a cross-sectional view of the backlight unit 2 of the first embodiment.
  • the base material 7 is arrange
  • the diffusion plate 6 is provided above the plurality of LEDs 10 so as not to overlap with the constant current IC 20.
  • the base 7 on which the constant current IC 20 and the plurality of LEDs 10 are mounted is the bezel 5 in which the back surface which is the surface opposite to the mounting surface of the constant current IC 20 and the plurality of LEDs 10 is made of metal.
  • the heat generated from the constant current IC 20 and the plurality of LEDs 10 can be dissipated to the bezel 5 through the base 7. Therefore, the heat dissipation efficiency can be increased.
  • the constant current IC 20 and the plurality of LEDs 10 may be mounted directly on the surface of the bezel 5 instead of on the substrate 7. According to this, since the heat generated from the constant current IC 20 and the plurality of LEDs 10 is directly dissipated to the bezel 5, it is possible to further enhance the radiation efficiency.
  • FIG. 21 is a cross-sectional view showing a configuration of a liquid crystal module 304 for television.
  • the liquid crystal module 304 has a direct type backlight unit in which the FPC 307 on which the LED array 12 is mounted and the diffusion plate 6 disposed above the LED array 12 are stored in the bezel 305. Further, the side wall of the bezel 505 in the lower frame is inclined, and the outer surface of the side wall of the inclined bezel 505 (the surface opposite to the side on which the diffusion plate 6, the LED array 12 and the FPC 307 are stored) A display control board 303 on which an LED driver IC 340, a coil 332 and the like are mounted is disposed.
  • the display control substrate 303 on which the LED driver IC 340, the coil 332, and the like are mounted can be disposed on the outer surface of the side wall of the inclined bezel 505.
  • the said structure since a certain amount of thickness is required, it can not apply to the liquid crystal module for manufacturing a notebook PC with severe thickness restrictions.
  • FIG. 7 is a diagram showing the configuration of a display control board used in a conventional notebook PC.
  • FIG. 8 is an enlarged view of a part of the display control board of FIG.
  • the display control board 203 is provided with a connector 250, an LED driver IC 240, a diode 231 and a coil 232.
  • An FPC 207 extending from the backlight unit 202 to the display control board 203 is connected to the connector 250.
  • the number of pins of the connector 250 is ten, and the coil 232 has a size of 4 mm ⁇ 4 mm and a thickness of about 1.2 mm.
  • the width Y 203 of the display control board 203 is about 8 mm.
  • an area including a part of the LED driver IC 240 (a part including the constant current circuit 220) and the peripheral circuit is a constant current circuit block 229.
  • a region including another part of the LED driver IC 240 (a portion including the booster circuit 230) and a peripheral circuit having the diode 231 and the coil 232 is a booster circuit block 233.
  • the peripheral circuits of the constant current circuit block 229 and the peripheral circuits of the booster circuit block 233 shown in FIG. 8 are merely examples, and differ depending on the type and application of the liquid crystal module.
  • the peripheral circuits of the booster circuit block 233 require a larger number of circuit components than the peripheral circuits of the constant current circuit block 229.
  • the diode 231 and the coil 232 included in the peripheral circuit of the booster circuit block 233 have a large area compared with other circuit components, and further, the vicinity of another part of the LED driver IC 240 (part including the booster circuit 230). Need to be
  • the display control board 203 Assuming that a large number of sets of the booster circuit block 233 and the constant current circuit block 229 are provided on the display control board 203 as the number of LEDs to be controlled increases, the display control board 203 is increased in width Y203, etc. The area of the substrate 203 needs to be increased.
  • booster circuit blocks 233 having this large area are provided in the backlight unit 202, it is necessary to greatly enlarge the lower frame of the backlight unit 202 or to greatly expand the thickness of the backlight unit 202. There is. Alternatively, it is necessary to provide the display control substrate 203 with the diodes 231 and the coils 232 included in the peripheral circuits of some of the plurality of booster circuit blocks 233 among the plurality of booster circuit blocks 233.
  • the constant current circuit block 229 has a smaller area than the booster circuit block 233.
  • the backlight unit 2 of the present embodiment corresponds to the substrate 7, the plurality of LED arrays 12 disposed on the substrate 7, and the respective LED arrays 12.
  • a plurality of constant current ICs provided on the substrate 7 are provided.
  • Each constant current IC includes a plurality of constant current circuits C1 to C16 connected to the cathodes of the respective LED strings of the corresponding LED array 12.
  • constant current circuits C 1 to C 16 for supplying a constant current to the respective LED strings 11 included in the LED array 12 are collectively provided in the constant current IC 20.
  • the constant current circuit is provided on the substrate 7.
  • the display control board 3 is provided with a voltage generation circuit block 33 for supplying a desired voltage to the anode of each LED row of the LED array 12.
  • the area of the display control board is increased compared to the case where the LED driver in which the constant current circuit and the booster circuit are integrated as shown in FIGS. 17 and 18 are provided on the display control board. It can be suppressed. That is, according to the above configuration, it is possible to configure the direct type backlight unit 2 while suppressing an increase in the area of the display control substrate 3.
  • the backlight unit 2 is a direct type backlight unit not provided with the voltage generation circuit.
  • the heat generation source can be dispersed, so that heat generation can also be suppressed.
  • the voltage generation circuit has a larger power loss than a constant current circuit, and thereby generates a large amount of heat.
  • GND can be sufficiently obtained, and power loss can be reduced.
  • relatively large circuit parts can be selected for the size and thickness of the current generating circuit and peripheral circuits, so the boosting efficiency is improved. Also, heat generation can be reduced.
  • the maximum thickness of the circuit component in the case of being provided on a display control substrate for a television is about 12 mm
  • the maximum thickness of the circuit component in the case of being provided on a display control substrate for a notebook PC is about 1.2 mm
  • the maximum thickness of the circuit component in the case of being provided on the FPC of the notebook PC is about 0.9 mm.
  • the number of pins of the connector is considered.
  • the number of pins of the connector is designed to be about 10 to 16.
  • the number of pins of the connector 250 shown in FIGS. 7 and 8 is ten, of which two are connected to the anodes of the plurality of LED arrays 12 and six are connected to the cathodes of the LED array 12.
  • 2 is NC (No Connection: not connected).
  • the liquid crystal module 4 for example, it is assumed that one screen is divided into 128 and local dimming is performed, and the one screen is driven by eight 16ch constant current ICs and two voltage generation ICs.
  • the number of pins is 2 for anode, 4 for GND, 1 for logic power supply, 4 for SPI, 1 for EN and 2 for NC, the total number of pins is 16 It will be enough.
  • the installation area of the connector for connecting the FPC provided on the display control substrate can be reduced.
  • the number of voltage generation ICs 30 is smaller than the number of constant current ICs 20.
  • the LED driver IC 240 When the LED driver IC 240 is provided outside the backlight unit 202 as shown in FIGS. 17 and 18, since the booster circuit and the constant current circuit are integrated, the booster circuit and the constant current circuit are fixed in the liquid crystal module. The same number of current circuits were present.
  • the voltage generation IC 30 can be smaller than the constant current circuits C1 to C16. . Furthermore, the voltage generation IC 30 can be less than the constant current IC 20. This can reduce the cost.
  • the load on the voltage generation IC 30 can also be reduced. Therefore, it is possible to drive more constant current ICs (that is, each LED controlled by the constant current IC) with less voltage generation IC.
  • one or more voltage generation ICs 30 may be provided not on the display control board 3 but on the main control board 9.
  • FIG. 10 is a diagram illustrating the configuration of the electronic device 1 of the second embodiment.
  • the number of voltage generation ICs 30 may be an integer (but one or more) of the number of constant current ICs 20.
  • FIG. 10 shows an example in which two voltage generation ICs 30 that are one fourth of the eight constant current ICs 20 are provided.
  • the load of the voltage generation IC 30 can be equally divided by setting the number of voltage generation ICs 30 to be an integral number (but one or more) of the number of constant current ICs 20. Therefore, the peripheral circuits included in the voltage generation IC 30 As a result, it is possible to select an optimal and inexpensive peripheral circuit.
  • FIG. 11 is a diagram illustrating the configuration of the electronic device 1 of the third embodiment.
  • FIG. 12 is a diagram illustrating configurations of a constant current IC 20 and a voltage generation IC 30 included in the electronic device 1 of the third embodiment.
  • FIG. 13 is a diagram showing how a plurality of constant current ICs are connected in parallel to a voltage generation IC.
  • two circuits including two constant current ICs 20 and one voltage generation IC 30 are provided.
  • the number of the constant current IC 20, the voltage generation IC 30, and the circuit including them is not limited to the number shown in FIG.
  • the constant current IC 20 includes, in addition to the constant current circuits C1 to C16 and the channels ch1 to ch16, the channels ch17 to ch20, the abnormality detection circuit 24, and the abnormality condition notification signal input circuit 25. And an abnormal condition notification signal output circuit 26.
  • the constant current IC 20 may include the constant current circuit block control circuit 22 and the control signal input circuit 21 shown in FIG.
  • the abnormal state notification signal input circuit 25 is connected to the channel ch17 and the channel ch18.
  • the abnormal state notification signal output circuit 26 is connected to the channel ch19 and the channel ch20.
  • the abnormality detection circuit 24 detects an abnormal state of the constant current circuits C1 to C16 by monitoring each of the constant current circuits C1 to C16.
  • the abnormal state is, for example, an abnormal current, an abnormal voltage, or an abnormal temperature.
  • the abnormality detection circuit 24 monitors the current flowing in each of the constant current circuits C1 to C16, compares it with a predetermined upper limit current value set in advance, and compares it with the upper limit current value. If it is large, it is judged as an abnormal current.
  • the channel ch20 of the first stage constant current IC20 is connected to the channel ch17 of the second stage constant current IC20.
  • the channel ch 20 of the second stage constant current IC 20 is connected to the voltage generation IC 30.
  • the channel ch19 of the first stage constant current IC20 is connected to the channel ch18 of the second stage constant current IC20.
  • the channel ch19 of the second stage constant current IC 20 is connected to the voltage generation IC 30.
  • the abnormal state detection circuit 24 When the abnormal state detection circuit 24 detects an abnormal state of any of the constant current circuits C1 to C16, it outputs an abnormal state notification signal DATA, which is a signal notifying an abnormal state, to the abnormal state notification signal output circuit 26.
  • an abnormal state notification signal DATA which is a signal notifying an abnormal state
  • the abnormality detection circuit 24 of the first stage constant current IC 20 detects an abnormal state of any of the constant current circuits C1 to C16, it outputs an abnormal state notification signal DATA to the abnormal state notification signal output circuit 26. .
  • the abnormal state notification signal output circuit 26 of the first stage constant current IC 20 outputs the abnormal state notification signal DATA from the channel ch 19 and outputs the clock signal CLK from the channel ch 20.
  • the abnormal condition notification signal DATA output from the channel ch19 of the first stage constant current IC20 is input to the abnormal condition notification signal input circuit 25 of the second stage constant current IC20 through the channel ch18
  • the clock signal CLK output from the channel ch20 of the first stage constant current IC20 is input to the abnormal state notification signal input circuit 25 of the second stage constant current IC20 through the channel ch17.
  • the abnormal state notification signal input circuit 25 of the second stage constant current IC 20 outputs the abnormal state notification signal DATA and the clock signal CLK inputted thereto to the abnormal state notification signal output circuit 26 of the second stage constant current IC 20. Output to
  • the abnormal state notification signal output circuit 26 of the second stage constant current IC 20 outputs the input abnormal state notification signal DATA from the channel ch 19 and outputs the clock signal CLK from the channel ch 20.
  • both the abnormal state notification signal DATA output from the channel ch19 of the second stage constant current IC20 and the clock signal CLK output from the channel ch20 of the second stage constant current IC20 are abnormal state notification signal receiving circuits. It is input to 35.
  • the abnormal condition notification signal receiving circuit 35 outputs the input abnormal condition notification signal DATA and the clock signal CLK to the voltage generation operation control circuit 36.
  • the voltage generation IC stops the generation of the voltage. Thereby, the voltage supplied to the anode of each LED array 12 is also stopped, and each LED array 12 is turned off. That is, the current flowing in the constant current circuits C1 to C16 of the first and second stage constant current ICs 20 is also stopped.
  • a path in which the channel ch19 of the first stage constant current IC20 and the channel ch18 of the second stage constant current IC20 are connected, and the channel ch19 of the second stage constant current IC20 and the voltage generation IC 30 are connected Is a path for transmitting and receiving an abnormal state notification signal which is a signal notifying an abnormal state.
  • the area allocated for installing a connector for connecting the FPC and the display control board is very small, and it is necessary to reduce the number of pins of the connector.
  • the path which transmits / receives an abnormal condition notification signal which is a signal which notifies an abnormal condition among a plurality of constant current IC20 and voltage generation IC30 is connected in series.
  • an abnormal condition notification signal which is a signal which notifies an abnormal condition among a plurality of constant current IC20 and voltage generation IC30
  • the number of wires can be reduced by connecting in series a path for transmitting and receiving an abnormal state notification signal which is a signal notifying an abnormal state between the plurality of constant current ICs 20 and the voltage generation IC 30.
  • a backlight unit is a direct-type backlight unit, comprising: a substrate; and one or more LED arrays to which a plurality of LEDs disposed on the substrate are connected; And one or more constant current ICs for supplying constant current to the LEDs included in the LED array corresponding to the array, and the LED array includes a plurality of LEDs connected in series.
  • the constant current IC includes a plurality of constant current circuits connected to each of the plurality of LED strings.
  • a plurality of constant current circuits for supplying a constant current to the plurality of LED rows included in the LED array are collectively provided in the constant current IC. Therefore, among the constant current IC and the circuit for supplying a desired voltage to the anodes of the plurality of LED strings, the constant current IC is provided on the base material and desired for the anodes of the plurality of LED strings.
  • the circuit for supplying the voltage V.sub.2 can be provided on another substrate different from the above substrate.
  • the constant current IC is a control signal input circuit that acquires a control signal input to the constant current IC, and an instruction from the control signal input circuit And a constant current control circuit for adjusting the current flowing from each of the LED rows to each of the constant current circuits based on a signal. According to the above configuration, it is possible to adjust the current flowing for each of the LED strings in the LED array. Thereby, the brightness can be adjusted for each of the LED rows in the LED array.
  • the backlight unit, the display control substrate, and the display control substrate are disposed, and include a voltage generation IC and peripheral circuit components And a voltage generation circuit block for supplying a voltage to the anodes of the columns.
  • the number of the voltage generation ICs may be smaller than the number of the constant current ICs. This can reduce the cost.
  • the number of voltage generation ICs may be an integer (but one or more) of the number of the constant current ICs. According to the above configuration, since loads of a plurality of voltage generation ICs can be equally divided, it is possible to select an optimal and inexpensive peripheral circuit as a peripheral circuit included in the voltage generation IC.
  • the plurality of constant current ICs and the voltage generation IC connect in series a path for transmitting and receiving an abnormal state notification signal which is a signal notifying an abnormal state. It may be done. According to the above configuration, the number of wires can be reduced.
  • the backlight unit stores the base material, the one or more LED arrays, and the one or more constant current ICs
  • the bezel is in contact with a surface of the base opposite to the side on which the one or more LED arrays and the one or more constant current ICs are disposed in the base.
  • the backlight unit stores the one or more LED arrays and the one or more constant current ICs, and is made of metal.
  • a bezel may be provided, and the substrate may be part of the bezel.
  • the heat radiation efficiency can be increased.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Nonlinear Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Planar Illumination Modules (AREA)
  • Liquid Crystal (AREA)

Abstract

La présente invention permet d'obtenir une unité de rétroéclairage direct, tout en supprimant une augmentation de la taille d'un substrat de commande d'affichage. Une unité de rétroéclairage direct (2) selon la présente invention est conçue de sorte qu'un CI à courant constant (20) comportant une pluralité de circuits à courant constant (C1-C16) soit disposé sur un substrat (7) pourvu d'une DEL (10).
PCT/JP2018/028877 2017-08-08 2018-08-01 Unité de rétroéclairage et dispositif électronique Ceased WO2019031355A1 (fr)

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JP2021157003A (ja) * 2020-03-26 2021-10-07 ダイハツ工業株式会社 ヘッドアップディスプレイ装置
JP2022002208A (ja) * 2020-06-22 2022-01-06 グローバル テクノロジーズ カンパニー リミテッド ディスプレイのためのバックライト装置およびその電流制御集積回路

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2021157003A (ja) * 2020-03-26 2021-10-07 ダイハツ工業株式会社 ヘッドアップディスプレイ装置
JP7404128B2 (ja) 2020-03-26 2023-12-25 ダイハツ工業株式会社 ヘッドアップディスプレイ装置
JP2022002208A (ja) * 2020-06-22 2022-01-06 グローバル テクノロジーズ カンパニー リミテッド ディスプレイのためのバックライト装置およびその電流制御集積回路
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