Display module and electronic apparatus

Abstract

To improve the accuracy of measuring the temperature of an electro-optical device.SOLUTION: A display module comprises: an electro-optical device that has a temperature detection element, and displays an image; a wiring board that has a driving circuit driving the electro-optical device; and a circuit board that has a first control circuit controlling the driving circuit, and is electrically connected to the electro-optical device via the wiring board. The driving circuit includes a measuring circuit that measures the temperature of the electro-optical device on the basis of an output signal from the temperature detection element in a fly-back period of the electro-optical device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a display module and an electronic device. [Background technology]

[0002] The liquid crystal panel mounted in the projector as a light valve is irradiated with strong light emitted from the light source, so the characteristics of the liquid crystal panel are likely to change as the temperature rises. Therefore, a technology has been proposed that uses a temperature detection element to detect the temperature of the liquid crystal panel and adjusts the temperature of the liquid crystal panel based on the detected temperature value.

[0003] For example, in the technology described in Patent Document 1, a diode is provided as a temperature detection element on a substrate constituting a liquid crystal panel, and an A / D converter that converts the forward voltage Vf of the diode into a digital value is provided on a circuit board electrically connected to the liquid crystal panel via a flexible wiring board. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-62887 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology of Patent Document 1, the temperature detection element disposed on the liquid crystal panel and the A / D converter disposed on the circuit board are electrically connected via a flexible wiring board, which means that the distance between the temperature detection element and the A / D converter is long, and therefore the forward voltage Vf of the diode input to the A / D converter is susceptible to fluctuations due to the influence of disturbance noise.

[0006] Furthermore, with the technology of Patent Document 1, it is difficult to perfectly synchronize the timing of temperature measurement, i.e., the timing at which the A / D converter captures the diode forward voltage Vf, with the timing at which the drive IC (Integrated Circuit) supplies image signals and drive signals to the liquid crystal panel. Therefore, depending on the timing of temperature measurement, the diode forward voltage Vf captured by the A / D converter may fluctuate due to the influence of power supply noise generated by the signals being supplied from the drive IC to the liquid crystal panel.

[0007] If the forward voltage Vf of the diode input to the A / D converter fluctuates due to the two reasons described above, it becomes difficult to obtain accurate temperature data. [Means for solving the problem]

[0008] A display module according to one embodiment of the present invention comprises an electro-optical device having a temperature detection element and displaying an image, a wiring board having a drive circuit for driving the electro-optical device, and a circuit board having a first control circuit for controlling the drive circuit and electrically connected to the electro-optical device via the wiring board, wherein the drive circuit includes a measurement circuit for measuring the temperature of the electro-optical device based on the output signal of the temperature detection element during the flyback period of the electro-optical device.

[0009] A display module according to one embodiment of the present invention comprises an electro-optical device having a temperature detection element and displaying an image, a wiring board, and a circuit board electrically connected to the electro-optical device via the wiring board, wherein the electro-optical device has a drive circuit for driving the electro-optical device, the circuit board has a first control circuit for controlling the drive circuit, and the drive circuit includes a measurement circuit for measuring the temperature of the electro-optical device based on the output signal of the temperature detection element during the flyback period of the electro-optical device.

[0010] An electronic device according to one aspect of the present invention includes the display module according to the above aspect. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view showing a schematic configuration of a liquid crystal panel used in a display module according to a first embodiment. [Figure 2] FIG. 1 is a diagram showing a schematic configuration of a display module according to a first embodiment. [Figure 3] FIG. 2 is a circuit diagram showing an example of a temperature detection circuit and a measurement circuit. [Figure 4] FIG. 2 is a diagram showing the operating state of a liquid crystal panel during one horizontal scanning period. [Figure 5] FIG. 2 is a diagram schematically showing a video signal in one frame period. [Figure 6] FIG. 10 is a diagram showing a schematic configuration of a display module according to a second embodiment. [Figure 7] FIG. 1 is a diagram showing a schematic configuration of a projector as an example of an electronic device. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the scale of each component may differ from the actual scale in order to make each component recognizable. Furthermore, in the following drawings, X, Y, and Z axes are provided as mutually orthogonal coordinate axes as necessary, and in each drawing, the direction indicated by each arrow along the axis is the + direction, and the direction opposite to the + direction is the - direction.

[0013] 1. First embodiment of display module 1 is a plan view showing a schematic configuration of a liquid crystal panel 100 used in a display module 1000 of the first embodiment. In FIG. 1, the +X direction may be referred to as right or right side, and the -X direction may be referred to as left or left side. The +Y direction may be referred to as up or upper side, and the -Y direction may be referred to as down or lower side. Furthermore, viewing from the +Z direction is referred to as planar view or planar.

[0014] For example, the liquid crystal panel 100 in this embodiment is an active-drive liquid crystal panel in which a plurality of pixels P, each having a pixel switching element such as a TFT (Thin Film Transistor), are arranged in a display area E. This liquid crystal panel 100 is combined with a wiring board 200 and a circuit board 300, which will be described later, to form a display module 1000, and can be suitably used as a light modulation device in a projector, which is an example of an electronic device. The liquid crystal panel 100 has a temperature detection element and is an example of an electro-optical device that displays an image.

[0015] The liquid crystal panel 100 includes an element substrate 1 and an opposing substrate 2. The element substrate 1 and opposing substrate 2 are bonded to each other via a sealant 3. The sealant 3 is provided in a frame shape along the outer edge of the opposing substrate 2. The sealant 3 is an adhesive made of a photocurable resin, a thermosetting resin, or the like, and includes a gap material such as glass fiber or glass beads for setting the gap between the element substrate 1 and the opposing substrate 2 to a predetermined value. Note that only a portion of the sealant 3 is shown in FIG. 1, and the remaining portion of the sealant 3 is omitted as appropriate.

[0016] Although not shown in FIG. 1, a liquid crystal layer is disposed in a region sandwiched between the element substrate 1 and the counter substrate 2 and surrounded by the sealant 3. For example, the liquid crystal layer is formed by a liquid crystal dropping method in which liquid crystal is dropped. When the liquid crystal layer is formed by the liquid crystal dropping method, the liquid crystal panel 100 does not have a liquid crystal injection port for injecting the liquid crystal. The liquid crystal layer is made of, for example, liquid crystal having negative dielectric anisotropy.

[0017] The element substrate 1 has a display area E in an area surrounded by a sealing material 3. In the display area E, a plurality of pixels P are arranged in a matrix. In the display area E, a plurality of signal lines 5 extending in the Y-axis direction are arranged at regular intervals in the X-axis direction. In the display area E, a plurality of scanning lines 6 extending in the X-axis direction are arranged at regular intervals in the Y-axis direction. Each pixel P is arranged at a position where the signal line 5 and the scanning line 6 intersect.

[0018] Although not shown in Fig. 1, each pixel P includes a light-transmitting pixel electrode and a pixel switching element arranged corresponding to the pixel electrode. The pixel electrode is a transparent electrode made of a transparent conductive material such as ITO (Indium Tin Oxide). The pixel switching element is, for example, an N-channel TFT.

[0019] For example, each signal line 5 is electrically connected to the source of the pixel switching element of each pixel P corresponding to each signal line 5. Each scanning line 6 is electrically connected to the gate of the pixel switching element of each pixel P corresponding to each scanning line 6. In each pixel P, the drain of the pixel switching element is electrically connected to the pixel electrode.

[0020] The element substrate 1 includes a signal line driving circuit 9 and a scanning line driving circuit 10. In the region between the display region E and the sealing material 3, the signal line driving circuit 9 is disposed below the display region E, and the scanning line driving circuit 10 is disposed on the left side of the display region E. The lower ends of the signal lines 5 are electrically connected to the signal line driving circuit 9. The left ends of the scanning lines 6 are electrically connected to the scanning line driving circuit 10.

[0021] For example, the signal line driving circuit 9 includes a plurality of demultiplexers 35. For example, each demultiplexer 35 has four switching elements 11. In FIG. 1, only the four switching elements 11 included in the rightmost demultiplexer 35 among the plurality of demultiplexers 35 included in the signal line driving circuit 9 are illustrated. For example, the switching element 11 is an N-channel TFT, similar to the pixel switching elements.

[0022] The drain (D) of each switching element 11 is electrically connected to the signal line 5 corresponding to that switching element 11. The source (S) of each switching element 11 is electrically connected to a video signal terminal 12. The video signal terminal 12 is one of a plurality of mounting terminals arranged at the lower end of the element substrate 1, and is used as an input terminal for a video signal VID.

[0023] Of the four switching elements 11, the gate (G) of the switching element 11 located on the rightmost side is electrically connected to a first selection signal terminal 13. The first selection signal terminal 13 is one of a plurality of mounting terminals, and is used as an input terminal for a first selection signal SEL1.

[0024] Of the four switching elements 11, the gate of the switching element 11 located second from the right is electrically connected to a second selection signal terminal 14. The second selection signal terminal 14 is one of a plurality of mounting terminals, and is used as an input terminal for a second selection signal SEL2.

[0025] Of the four switching elements 11, the gate of the switching element 11 located third from the right is electrically connected to a third selection signal terminal 15. The third selection signal terminal 15 is one of a plurality of mounting terminals, and is used as an input terminal for a third selection signal SEL3.

[0026] Of the four switching elements 11, the gate of the leftmost switching element 11 is electrically connected to a fourth selection signal terminal 16. The fourth selection signal terminal 16 is one of a plurality of mounting terminals, and is used as an input terminal for a fourth selection signal SEL4. In the following description, the first selection signal SEL1 to the fourth selection signal SEL4 may be collectively referred to as the selection signal SEL.

[0027] The first selection signal SEL1 to the fourth selection signal SEL4 control the on or off of four switching elements 11 included in one demultiplexer 35. Each switching element 11 is controlled to be exclusively on during one horizontal scanning period, and the video signal VID is distributed in synchronization with the on timing of each switching element 11 and input to the video signal terminal 12, whereby the desired video signal VID is supplied to each signal line 5.

[0028] To ensure a write capability suitable for high-speed driving of the liquid crystal panel 100, the channel width of each switching element 11 is large. Therefore, typically, an arrangement in which the gate electrodes of each switching element 11 extend in the Y-axis direction is widely used. The signal line driving circuit 9 is composed of a plurality of demultiplexers 35, each having four switching elements 11 as described above. In other words, the signal line driving circuit 9 includes a plurality of switching elements 11 electrically connected to a plurality of signal lines 5 in a one-to-one relationship.

[0029] For example, if the liquid crystal panel 100 is an FHD (Full-High Definition) panel, the signal line driving circuit 9 includes 1920 / 4=480 demultiplexers 35. For example, if each demultiplexer 35 has eight switching elements 11, the signal line driving circuit 9 includes 1920 / 8=240 demultiplexers 35.

[0030] For example, the scanning line driving circuit 10 is configured with a sequential selection circuit such as a shift register. Therefore, typically, a clock signal main line 17, which is the main wiring for the clock signal CLY, extends in the Y-axis direction, and multiple clock signal branch lines 18 for supplying the clock signal CLY to the unit circuits of each shift register extend from the clock signal main line 17 to the right. The clock signal main line 17 is electrically connected to a clock signal terminal 19. The clock signal terminal 19 is one of multiple mounting terminals and is used as an input terminal for the clock signal CLY.

[0031] FIG. 1 illustrates a configuration in which the clock signal CLY input to the clock signal terminal 19 is directly supplied to the scanning line driving circuit 10. However, a configuration may also be adopted in which the clock signal CLY input to the clock signal terminal 19 is a low-amplitude signal, which is converted into a high-amplitude signal by a level shift circuit disposed on the element substrate 1 and then supplied to the scanning line driving circuit 10.

[0032] 1 illustrates a configuration in which one clock signal CLY is supplied to the scanning line driving circuit 10, but a configuration in which an inverted signal CLYB of the clock signal CLY is supplied to the scanning line driving circuit 10 together with the clock signal CLY may also be employed. In this case, the phase difference between these two clock signals CLY and CLYB is adjusted by a phase difference correction circuit, and then the two clock signals CLY and CLYB are supplied to the shift register via a buffer circuit.

[0033] An output control signal ENBY for shaping the scan line selection waveform is supplied to the scanning line driving circuit 10 via an output control signal line 20 extending in the Y-axis direction. The output control signal line 20 is electrically connected to an output control signal terminal 21. The output control signal terminal 21 is one of multiple mounting terminals and is used as an input terminal for the output control signal ENBY. For example, the output control signal ENBY is input to an AND circuit together with the output signals of each stage of a shift register, and the output signal of the AND circuit is supplied to the scanning line 6 via a buffer circuit as appropriate as a scanning signal for turning on the pixel switching element.

[0034] As can be understood from the above description, the scanning line driving circuit 10 sequentially selects the multiple scanning lines 6 arranged in the display area E in synchronization with the clock signal CLY. More specifically, the scanning line driving circuit 10 sequentially supplies a scanning signal to each scanning line 6 in synchronization with the clock signal CLY. The period during which one scanning line 6 is selected, i.e., the period during which a scanning signal is supplied to one scanning line 6, is included in one horizontal scanning period.

[0035] 1 illustrates a configuration in which one scanning line driving circuit 10 is arranged on the left side of the display region E, but in reality, to accommodate high-speed driving, a configuration in which scanning line driving circuits 10 are arranged on both the left and right sides of the display region E is often used. In addition, although not shown in FIG. 1, the element substrate 1 includes a first alignment film arranged to cover the display region E.

[0036] The counter substrate 2 includes a light-shielding film 27 having light-shielding properties, a light-transmitting common electrode, and a second alignment film disposed to cover the common electrode. The common electrode and the second alignment film are not shown in FIG. 1 . The light-shielding film 27 is disposed to surround the display area E in a plan view. In FIG. 1 , only a portion of the light-shielding film 27 is shown, and the remaining portion of the light-shielding film 27 is omitted as appropriate. The common electrode is formed of a transparent conductive material such as ITO. The common electrode is electrically connected to two common potential terminals 31 of the element substrate 1 via transfers 30 disposed corresponding to the four corners of the counter substrate 2.

[0037] The common potential terminal 31 is one of the multiple mounting terminals and is used as an input terminal for a common potential Vcom. The common potential Vcom input to the common potential terminal 31 is supplied to the common electrode via four transfers 30. Although not shown in the figure, the common potential Vcom input to the common potential terminal 31 is also supplied to one end of an auxiliary capacitor included in a pixel circuit arranged on the element substrate 1. The common potential Vcom may be supplied to the common electrode and the auxiliary capacitor via separate systems.

[0038] The element substrate 1 includes a temperature detection circuit 22 that detects the temperature of the liquid crystal panel 100. The temperature detection circuit 22 is electrically connected to a first temperature detection terminal 23 and a second temperature detection terminal 24. Each of the first temperature detection terminal 23 and the second temperature detection terminal 24 is one of a plurality of mounting terminals, and is used to electrically connect the temperature detection circuit 22 to a measurement circuit 220, which will be described later in detail. The temperature detection circuit 22 includes a diode 51 as a temperature detection element. In other words, the liquid crystal panel 100 has a diode 51 as a temperature detection element.

[0039] For example, the temperature detection circuit 22 is disposed at a position overlapping with the light-shielding film 27 in a plan view. Although Fig. 1 shows an example in which the temperature detection circuit 22 is disposed at the lower left of the display area E in the area overlapping with the light-shielding film 27 in a plan view, the positioning of the temperature detection circuit 22 is not limited to this. However, it is desirable that the temperature detection circuit 22 be disposed at a position close to the first temperature detection terminal 23 and the second temperature detection terminal 24 so that the distance between the temperature detection circuit 22 and the measurement circuit 220 is as short as possible.

[0040] 2 is a diagram showing a schematic configuration of a display module 1000 according to the first embodiment. The display module 1000 includes a liquid crystal panel 100, a wiring board 200, and a circuit board 300. The wiring board 200 includes a driving IC (Integrated Circuit) 210 that drives the liquid crystal panel 100. For example, the wiring board 200 is a flexible printed circuit board such as an FPC (Flexible Printed Circuit). The circuit board 300 includes a first control circuit 310 that controls the driving IC 210.

[0041] The liquid crystal panel 100 is electrically connected to the circuit board 300 via the wiring board 200. More specifically, of the multiple mounting terminals arranged on the element substrate 1 of the liquid crystal panel 100, two common potential terminals 31 are electrically connected to a first control circuit 310 of the circuit board 300 via the wiring board 200. The other mounting terminals, including the video signal terminal 12, the first selection signal terminal 13, the second selection signal terminal 14, the third selection signal terminal 15, the fourth selection signal terminal 16, the clock signal terminal 19, the output control signal terminal 21, the first temperature detection terminal 23, and the second temperature detection terminal 24, are electrically connected to a driving IC 210 of the wiring board 200. The driving IC 210 is electrically connected to the first control circuit 310 of the circuit board 300. 2, among the multiple mounting terminals of the liquid crystal panel 100, mounting terminals other than the first temperature detection terminal 23 and the second temperature detection terminal 24 are not shown.

[0042] The clock signal CLY, the output control signal ENBY, the selection signal SEL, the video signal VID, etc. are supplied from the driving IC 210 to the liquid crystal panel 100. The common potential Vcom is supplied directly to the liquid crystal panel 100 from the first control circuit 310. During normal driving of the liquid crystal panel 100, the first control circuit 310 controls the driving IC 210 to cause the driving IC 210 to output various signals necessary for driving the liquid crystal panel 100. The driving IC 210 outputs the clock signal CLY, the output control signal ENBY, the video signal VID, the selection signal SEL, etc. to the liquid crystal panel 100 under the control of the first control circuit 310. The selection signal SEL includes a first selection signal SEL1 to a fourth selection signal SEL4. In addition to the above, signals output by the driving IC 210 also include a start pulse signal to the scanning line driving circuit 10, a scanning direction specification signal, etc.

[0043] 1, in the liquid crystal panel 100, the common potential Vcom input to the common potential terminal 31 is supplied to the common electrode via the transfer 30. The clock signal CLY input to the clock signal terminal 19 is supplied to the scanning line driving circuit 10 via the main clock signal line 17 and the branch clock signal line 18. The output control signal ENBY input to the output control signal terminal 21 is supplied to the scanning line driving circuit 10 via the output control signal line 20.

[0044] The video signal VID input to the video signal terminal 12 is supplied to the sources of the switching elements 11 of all the demultiplexers 35 included in the signal line drive circuit 9. For example, among the selection signals SEL, the first selection signal SEL1 to the fourth selection signal SEL4 input to the first selection signal terminal 13 to the fourth selection signal terminal 16 are supplied to the gate electrodes of the four switching elements 11 included in the demultiplexer 35 located at the rightmost side of the signal line drive circuit 9.

[0045] A video signal VID and a selection signal SEL are supplied to the signal line drive circuit 9, and a clock signal CLY and an output control signal ENBY are supplied to the scanning line drive circuit 10. As a result, scanning signals that switch the pixel switching elements of each pixel P to an ON state are sequentially supplied to each scanning line 6, and a potential applied to the pixel electrode of each pixel P is supplied to each signal line 5. As a result, the light transmittance of each pixel P becomes a value determined by the potential difference between the pixel electrode and the common electrode. The state in which the light transmittance of each pixel P is controlled in this manner, causing the liquid crystal panel 100 to operate as a light modulation device and display an image, is referred to as the normal driving state of the liquid crystal panel 100. Furthermore, during the normal driving state in which an image is displayed, AC driving is performed on each pixel P, and the polarity of the voltage applied to the liquid crystal layer of each pixel P is reversed every frame period in which updating of the transmittance state of the pixel P included in the display area E is completed.

[0046] The driving IC 210 includes a measurement circuit 220. The measurement circuit 220 is electrically connected to the temperature detection circuit 22 of the liquid crystal panel 100 via a first temperature detection terminal 23 and a second temperature detection terminal 24, among a plurality of mounting terminals arranged on the element substrate 1 of the liquid crystal panel 100. The measurement circuit 220 is also electrically connected to a first control circuit 310 of the circuit board 300. As will be described in detail later, the measurement circuit 220 measures the temperature of the liquid crystal panel 100 based on an output signal of a temperature detection element during a blanking period of the liquid crystal panel 100. In this embodiment, the temperature detection element is a diode 51 included in the temperature detection circuit 22, and the output signal of the temperature detection element is the forward voltage Vf of the diode 51.

[0047] 3 is a circuit diagram showing an example of the temperature detection circuit 22 and the measurement circuit 220. The temperature detection circuit 22 includes a diode 51 as a temperature detection element, an N-channel transistor 52, a first resistor element 53, a second resistor element 54, a third resistor element 55, a first capacitor 56, and a second capacitor 57.

[0048] The anode terminal of the diode 51 is electrically connected to the first temperature detection terminal 23 via the first resistor element 53. The cathode terminal of the diode 51 is electrically connected to the second temperature detection terminal 24 via the second resistor element 54. Although FIG. 3 shows an example in which one diode 51 is used as the temperature detection element, multiple diodes 51 connected in series may be used to increase the temperature detection sensitivity.

[0049] A drain terminal of the N-channel transistor 52 is electrically connected to an anode terminal of the diode 51. A source terminal of the N-channel transistor 52 is electrically connected to a cathode terminal of the diode 51. A gate terminal of the N-channel transistor 52 is electrically connected to the cathode terminal of the diode 51 via a third resistor element 55.

[0050] One end of the first capacitor 56 is electrically connected to the drain terminal of the N-channel transistor 52. The other end of the first capacitor 56 is electrically connected to the gate terminal of the N-channel transistor 52. One end of the second capacitor 57 is electrically connected to the gate terminal of the N-channel transistor 52. The other end of the second capacitor 57 is electrically connected to the source terminal of the N-channel transistor 52.

[0051] The measurement circuit 220 includes a constant current source 61, a buffer 62, an A / D converter 63, a second control circuit 64, a power supply wiring 65, and a ground wiring 66. The power supply wiring 65 is a wiring to which a power supply potential of the measurement circuit 220 is applied. The ground wiring 66 is a wiring to which a ground potential is applied. The power supply wiring 65 is electrically connected to the first temperature detection terminal 23 via the constant current source 61. The ground wiring 66 is electrically connected to the second temperature detection terminal 24.

[0052] The constant current source 61 is electrically connected between the power supply wiring 65 and the first temperature detection terminal 23, and supplies a drive current Id to the diode 51 via the first temperature detection terminal 23. The input terminal of the buffer 62 is electrically connected to the first temperature detection terminal 23. The output terminal of the buffer 62 is electrically connected to the A / D converter 63. The buffer 62 outputs the potential difference between the first temperature detection terminal 23 and the second temperature detection terminal 24 to the A / D converter 63 as a forward voltage Vf of the diode 51. For example, the buffer 62 is a voltage follower.

[0053] The A / D converter 63 is electrically connected to the second control circuit 64, and converts the forward voltage Vf of the diode 51 input from the buffer 62 into a digital value at a timing instructed by the second control circuit 64. The A / D converter 63 outputs the digital value of the forward voltage Vf of the diode 51 as temperature data to the second control circuit 64. The second control circuit 64 controls the A / D converter 63 and outputs the temperature data obtained from the A / D converter 63 to the first control circuit 310 of the circuit board 300.

[0054] The forward voltage Vf of the diode 51, which is generated when the drive current Id is supplied from the measurement circuit 220 to the temperature detection circuit 22, decreases linearly with an increase in temperature. In other words, the forward voltage Vf of the diode 51 is temperature dependent. Therefore, the temperature of the liquid crystal panel 100 can be measured by detecting the potential difference between the first temperature detection terminal 23 and the second temperature detection terminal 24 as the forward voltage Vf of the diode 51.

[0055] Furthermore, for example, when a surge current caused by static electricity flows into the temperature detection circuit 22 from the first temperature detection terminal 23, the first resistor element 53 suppresses voltage fluctuations while the gate potential of the N-channel transistor 52 rises. As a result, the N-channel transistor 52 turns on, and the surge current flows to the second temperature detection terminal 24 via the N-channel transistor 52. The period during which the N-channel transistor 52 remains on is determined by the first capacitor 56, the second capacitor 57, the third resistor element 55, and the gate capacitance of the N-channel transistor 52. After discharging, the gate potential of the N-channel transistor 52 returns to the off potential by the third resistor element 55. In this way, the circuit configuration of the temperature detection circuit 22 suppresses surge current flowing through the diode 51 due to static electricity or the like, thereby protecting the diode 51 from surge current.

[0056] In the first embodiment, the driving IC 210 disposed on the wiring board 200 that electrically connects the liquid crystal panel 100 to the circuit board 300 includes the measurement circuit 220. Therefore, compared to the conventional technology in which the measurement circuit 220 is disposed on the circuit board 300, the distance between the diode 51, which is a temperature detection element disposed on the liquid crystal panel 100, and the A / D converter 63 included in the measurement circuit 220 is shorter. Therefore, according to the first embodiment, the forward voltage Vf of the diode 51 that is input to the A / D converter 63 is less susceptible to the influence of external noise compared to the conventional technology, thereby improving the accuracy of temperature measurement of the liquid crystal panel 100.

[0057] Furthermore, in the first embodiment, in order to prevent the forward voltage Vf of the diode 51 taken into the A / D converter 63 from being affected by power supply noise, the second control circuit 64 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is taken into the A / D converter 63 during the flyback period of the liquid crystal panel 100.

[0058] 4 is a diagram showing the operating states of liquid crystal panel 100 during one horizontal scanning period. As shown in Fig. 4, one horizontal scanning period includes a horizontal back porch period (HBP) during which a precharge operation is performed, a horizontal display period during which a normal operation is performed, and a horizontal front porch period (HFP) during which a postcharge operation is performed.

[0059] During the horizontal back porch period, all of the first selection signal SEL1 to fourth selection signal SEL4 supplied from the driver IC 210 to the liquid crystal panel 100 are turned on, and all four switching elements 11 included in each demultiplexer in the signal line driver circuit 9 are turned on. During this horizontal back porch period, a constant precharge voltage is supplied from the driver IC 210 to the video signal terminal 12. As a result, the precharge voltage is supplied to all signal lines 5, and the precharge voltage is written to all pixels P connected to one scanning line 6.

[0060] During the horizontal display period, the first to fourth selection signals SEL1 to SEL4 supplied from the driver IC 210 to the liquid crystal panel 100 are turned on exclusively and sequentially, which causes the four switching elements 11 included in each demultiplexer 35 in the signal line driver circuit 9 to be turned on exclusively and sequentially. The video signal VID is distributed in synchronization with the on timing of each switching element 11 and input to the video signal terminal 12, so that the desired video signal VID is supplied to each signal line 5. As a result, a voltage corresponding to the video signal VID is written to all pixels P connected to one scanning line 6, and an image corresponding to the video signal VID is displayed.

[0061] During the horizontal front porch period, all of the first selection signal SEL1 to the fourth selection signal SEL4 supplied from the driver IC 210 to the liquid crystal panel 100 are turned off, and all of the four switching elements 11 included in each demultiplexer 35 in the signal line driver circuit 9 are turned off. During this horizontal front porch period, a constant voltage is supplied from the driver IC 210 to the video signal terminal 12.

[0062] Within one horizontal scanning period as described above, the horizontal back porch period in which the precharge operation is performed is the period in which the load on the liquid crystal panel 100 is greatest as viewed from the driver IC 210. Therefore, within one horizontal scanning period, the power supply noise generated during the horizontal back porch period in which the precharge operation is performed is the greatest.

[0063] Within one horizontal scanning period, the horizontal display period during which normal operation is performed is a period during which the load on the liquid crystal panel 100 as seen from the driver IC 210 changes depending on the video signal VID. For example, when a video signal VID with a large change in voltage value is supplied to the liquid crystal panel 100, such as when a dot pattern is displayed on the liquid crystal panel 100, the load on the liquid crystal panel 100 as seen from the driver IC 210 becomes large. In this way, the magnitude of the power supply noise generated during the horizontal display period during which normal operation is performed within one horizontal scanning period changes depending on the video signal VID.

[0064] Within one horizontal scanning period, the horizontal front porch period during which the post-charge operation is performed is the period during which the load on the liquid crystal panel 100 is the smallest as seen from the driver IC 210. Therefore, within one horizontal scanning period, the power supply noise generated during the horizontal front porch period during which the post-charge operation is performed is the smallest.

[0065] The second control circuit 64 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is taken into the A / D converter 63 during a horizontal front porch period within one horizontal scanning period. In other words, the second control circuit 64 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is taken into the A / D converter 63 during a flyback period included in the horizontal scanning period. This minimizes the influence of power supply noise on the forward voltage Vf of the diode 51 taken into the A / D converter 63, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100.

[0066] When a post-charge operation is performed before or after a horizontal back porch period in which a pre-charge operation is performed, the second control circuit 64 may control the A / D converter 63 so that the forward voltage Vf of the diode 51 is captured by the A / D converter 63 during the period in which the post-charge operation is performed before or after the horizontal back porch period.

[0067] FIG. 5 is a diagram schematically illustrating a video signal VID in one frame period. As shown in FIG. 5, the video signal VID in one frame period has retrace periods not only in the horizontal scanning period but also in the vertical scanning period. The vertical scanning period includes a vertical back porch period (VBP) and a vertical front porch period (VFP) as retrace periods. In FIG. 5, the hatched area W1 is the retrace period included in one frame period. The blank area W2 corresponds to the effective pixel area of ​​the liquid crystal panel 100. Symbol T1 corresponds to one block of the demultiplexer, and symbol T2 corresponds to one line of the scanning line 6.

[0068] The second control circuit 64 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is taken into the A / D converter 63 during a blanking interval included in the vertical scanning period. This makes it possible to further reduce the influence of power supply noise on the forward voltage Vf of the diode 51 taken into the A / D converter 63, thereby further improving the accuracy of measuring the temperature of the liquid crystal panel 100. When measuring the temperature of the liquid crystal panel 100 during a blanking interval included in the vertical scanning period, it is desirable to measure the temperature of the liquid crystal panel 100 with the signal output from the drive IC 210 to the liquid crystal panel 100 stopped.

[0069] (Effects of the first embodiment) As described above, the display module 1000 of the first embodiment includes a liquid crystal panel 100 having a diode 51 as a temperature detection element and displaying an image, a wiring board 200 having a driving IC 210 that drives the liquid crystal panel 100, and a circuit board 300 having a first control circuit 310 that controls the driving IC 210 and is electrically connected to the liquid crystal panel 100 via the wiring board 200. The driving IC 210 includes a measurement circuit 220 that measures the temperature of the liquid crystal panel 100 based on the forward voltage Vf of the diode 51 during the blanking period of the liquid crystal panel 100. In the first embodiment described above, the driving IC 210 disposed on the wiring board 200 that electrically connects the liquid crystal panel 100 to the circuit board 300 includes the measurement circuit 220. Therefore, compared to the conventional technology in which the measurement circuit 220 is disposed on the circuit board 300, the distance between the measurement circuit 220 and the diode 51 that is a temperature detection element disposed on the liquid crystal panel 100 is shorter. Therefore, according to the first embodiment, the forward voltage Vf of the diode 51 that is input to the measurement circuit 220 is less susceptible to disturbance noise compared to the conventional technology, thereby improving the accuracy of temperature measurement of the liquid crystal panel 100. Furthermore, in the first embodiment, the measurement circuit 220 measures the temperature of the liquid crystal panel 100 based on the forward voltage Vf of the diode 51 during the flyback period of the liquid crystal panel 100. This makes it possible to prevent the forward voltage Vf of the diode 51 input to the measurement circuit 220 from being affected by power supply noise, thereby further improving the accuracy of measuring the temperature of the liquid crystal panel 100.

[0070] In the display module 1000 of the first embodiment, the blanking period of the liquid crystal panel 100 is a blanking period included in the horizontal scanning period. According to the first embodiment, the forward voltage Vf of the diode 51 input to the measurement circuit 220 can be prevented from being affected by power supply noise generated during the horizontal scanning period, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100.

[0071] In the display module 1000 of the first embodiment, the blanking period of the liquid crystal panel 100 is a blanking period included in the vertical scanning period. According to the first embodiment, the forward voltage Vf of the diode 51 input to the measurement circuit 220 can be prevented from being affected by power supply noise generated during the vertical scanning period, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100.

[0072] In the display module 1000 of the first embodiment, the measurement circuit 220 includes a constant current source 61 that supplies a drive current Id to the diode 51, an A / D converter 63 that converts the forward voltage Vf of the diode 51 into a digital value, and a second control circuit 64 that controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is captured by the A / D converter 63 during the flyback period of the liquid crystal panel 100. In the first embodiment, the distance between the diode 51, which is a temperature detection element arranged on the liquid crystal panel 100, and the A / D converter 63 included in the measurement circuit 220 is shorter than in the conventional technology in which the measurement circuit 220 is arranged on the circuit board 300. Therefore, according to the first embodiment, the forward voltage Vf of the diode 51 input to the A / D converter 63 is less susceptible to the influence of external noise than in the conventional technology, thereby improving the accuracy of temperature measurement of the liquid crystal panel 100. Furthermore, in the first embodiment, the second control circuit 64 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is taken into the A / D converter 63 during the flyback period of the liquid crystal panel 100. This makes it possible to prevent the forward voltage Vf of the diode 51 taken into the A / D converter 63 from being affected by power supply noise, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100.

[0073] In the display module 1000 of the first embodiment, the liquid crystal panel 100 has a signal line driving circuit 9 including a plurality of demultiplexers 35. The liquid crystal panel 100, which is operated by the signal line drive circuit 9 including multiple demultiplexers 35, generates relatively large power supply noise. Therefore, by incorporating a measurement circuit 220 into the drive IC 210 disposed on the wiring substrate 200 and by having the measurement circuit 220 measure the temperature of the liquid crystal panel 100 based on the forward voltage Vf of the diode 51 during the blanking period of the liquid crystal panel 100, the effects of the power supply noise can be more effectively suppressed.

[0074] In the display module 1000 of the first embodiment, the temperature detection element is a diode 51. According to the first embodiment, the temperature detection element can be formed in the liquid crystal panel 100 together with the pixel switching element, etc., so there is no need to use another temperature detection element such as a thermistor to detect the temperature of the liquid crystal panel 100.

[0075] 2. Second embodiment of the display module 6 is a diagram showing a schematic configuration of a display module 2000 according to the second embodiment. In the second embodiment exemplified below, components common to the first embodiment are denoted by the same reference numerals as those used in the first embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0076] 6, the display module 2000 includes a liquid crystal panel 100A, a wiring substrate 200A, and a circuit substrate 300. The liquid crystal panel 100A of the second embodiment differs from the liquid crystal panel 100 of the first embodiment in that it includes a driving IC 210 that includes a measurement circuit 220. For example, in the second embodiment, the driving IC 210 is disposed in an area below the counter substrate 2 within the surface area of ​​the element substrate 1. In the liquid crystal panel 100A, the temperature detection circuit 22 is electrically connected to the measurement circuit 220 included in the driving IC 210 disposed on the element substrate 1.

[0077] The liquid crystal panel 100A is electrically connected to the circuit board 300 via the wiring board 200A. The wiring board 200A of the second embodiment electrically connects the liquid crystal panel 100A to the circuit board 300, but does not include the driving IC 210.

[0078] As in the first embodiment, the clock signal CLY, the output control signal ENBY, the selection signal SEL, the video signal VID, etc. are supplied from the driving IC 210 to the liquid crystal panel 100A. The common potential Vcom is supplied directly to the liquid crystal panel 100A from the first control circuit 310 on the circuit board 300. During normal driving of the liquid crystal panel 100A, the first control circuit 310 controls the driving IC 210 to cause the driving IC 210 to output various signals necessary for driving the liquid crystal panel 100A. Under the control of the first control circuit 310, the driving IC 210 outputs the clock signal CLY, the output control signal ENBY, the video signal VID, the selection signal SEL, etc. to the liquid crystal panel 100A.

[0079] In the second embodiment, the driving IC 210 disposed in the liquid crystal panel 100A includes a measuring circuit 220. Therefore, compared to the first embodiment in which the driving IC 210 is disposed on the wiring substrate 200, the distance between the diode 51, which is a temperature detection element disposed in the liquid crystal panel 100A, and the A / D converter 63 included in the measuring circuit 220 is shorter. Therefore, according to the second embodiment, the forward voltage Vf of the diode 51 input to the A / D converter 63 is less susceptible to the influence of disturbance noise compared to the first embodiment, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100A.

[0080] Also in the second embodiment, the second control circuit 64 included in the measurement circuit 220 controls the A / D converter 63 so that the forward voltage Vf of the diode 51 is captured by the A / D converter 63 during the flyback period of the liquid crystal panel 100A. This minimizes the influence of power supply noise on the forward voltage Vf of the diode 51 captured by the A / D converter 63, as in the first embodiment, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100A.

[0081] (Effects of the second embodiment) As described above, the display module 2000 of the second embodiment includes a liquid crystal panel 100A that displays an image and has a diode 51 as a temperature detection element, a wiring board 200A, and a circuit board 300 that is electrically connected to the liquid crystal panel 100A via the wiring board 200A. The liquid crystal panel 100A includes a driving IC 210 that drives the liquid crystal panel 100A. The circuit board 300 includes a first control circuit 310 that controls the driving IC 210. The driving IC 210 includes a measurement circuit 220 that measures the temperature of the liquid crystal panel 100A based on the forward voltage Vf of the diode 51 during the blanking period of the liquid crystal panel 100A. In the second embodiment described above, the driving IC 210 disposed in the liquid crystal panel 100A includes the measuring circuit 220. Therefore, compared to the first embodiment in which the driving IC 210 is disposed on the wiring substrate 200, the distance between the diode 51, which is a temperature detection element disposed in the liquid crystal panel 100A, and the measuring circuit 220 is shorter. Therefore, according to the second embodiment, the forward voltage Vf of the diode 51 received by the measuring circuit 220 is less susceptible to disturbance noise compared to the first embodiment, thereby further improving the accuracy of temperature measurement of the liquid crystal panel 100A. Furthermore, similar to the first embodiment, in the second embodiment, the measurement circuit 220 measures the temperature of the liquid crystal panel 100A during the flyback period of the liquid crystal panel 100A based on the forward voltage Vf of the diode 51. This makes it possible to prevent the forward voltage Vf of the diode 51 input to the measurement circuit 220 from being affected by power supply noise, thereby further improving the accuracy of measuring the temperature of the liquid crystal panel 100A.

[0082] 3. Overview of Electronic Devices 7 is a schematic diagram showing the configuration of a projector as an electronic device. In the following, a projector 10000 will be described as an example of an electronic device equipped with the display module 1000 of the first embodiment.

[0083] The projector 10000 is a three-plate projector and includes a lamp unit 1001 as a light source, dichroic mirrors 1011 and 1012 as a color separation optical system, a display module 1000B corresponding to blue light B, a display module 1000G corresponding to green light G, a display module 1000R corresponding to red light R, three reflecting mirrors 1111, 1112, and 1113, three relay lenses 1121, 1122, and 1123, a dichroic prism 1130 as a color synthesis optical system, and a projection lens 1140 as a projection optical system. An image is projected onto a screen 1200 by the projection optical system. The relay lenses 1121, 1122, and 1123 and the reflecting mirrors 1112 and 1113 constitute a relay lens system 1120.

[0084] The projector 10000 also includes a circuit board 1230 that is electrically connected to the display modules 1000B, 1000G, and 1000R. The circuit board 1230 is formed by combining the circuit boards 300 of the display modules 1000B, 1000G, and 1000R into a single board.

[0085] The above describes embodiments of the present disclosure, but the technical scope of the present disclosure is not limited to the above embodiments, and various modifications can be made within the scope that does not deviate from the spirit of the present disclosure.

[0086] For example, in the above embodiment, liquid crystal panels 100 and 100A are used as examples of electro-optical devices, but the electro-optical devices of the present disclosure are not limited to liquid crystal panels and may be other electro-optical devices such as OLED (Organic Light Emitting Diode) panels. Furthermore, in the present embodiment, projector 10000 is used as an example of an electronic device, but electronic devices equipped with a display module of the present disclosure are not limited to this. For example, the display module of the present disclosure may be applied to electronic devices such as 3D printers that use light emitted from a liquid crystal panel to harden a resin liquid, HUDs (Head-Up Displays), HMDs (Head-Mounted Displays), personal computers, digital cameras, and LCD televisions.

[0087] Summary of the Disclosure A summary of this disclosure is provided below.

[0088] (Appendix 1) A display module comprising: an electro-optical device having a temperature detection element and displaying an image; a wiring board having a drive circuit for driving the electro-optical device; and a circuit board having a first control circuit for controlling the drive circuit and electrically connected to the electro-optical device via the wiring board, wherein the drive circuit includes a measurement circuit for measuring the temperature of the electro-optical device based on an output signal of the temperature detection element during a flyback period of the electro-optical device.

[0089] In the display module described in Supplementary Note 1, a drive circuit disposed on a wiring board that electrically connects the electro-optical device to a circuit board includes a measurement circuit. Therefore, compared to conventional techniques in which the measurement circuit is disposed on a circuit board, the distance between the temperature detection element disposed on the electro-optical device and the measurement circuit is shorter. Therefore, compared to conventional techniques, the display module described in Supplementary Note 1 makes it possible to improve the accuracy of temperature measurement of the electro-optical device because the output signal of the temperature detection element that is input to the measurement circuit is less susceptible to disturbance noise. The measurement circuit measures the temperature of the electro-optical device based on the output signal of the temperature detection signal during the flyback period of the electro-optical device, thereby preventing the output signal of the temperature detection signal input to the measurement circuit from being affected by power supply noise, thereby further improving the accuracy of temperature measurement of the electro-optical device.

[0090] (Appendix 2) A display module comprising: an electro-optical device having a temperature detection element and displaying an image; a wiring board; and a circuit board electrically connected to the electro-optical device via the wiring board, wherein the electro-optical device has a drive circuit for driving the electro-optical device, the circuit board has a first control circuit for controlling the drive circuit, and the drive circuit includes a measurement circuit for measuring the temperature of the electro-optical device based on an output signal of the temperature detection element during a flyback period of the electro-optical device.

[0091] In the display module described in Supplementary Note 2, the drive circuit arranged in the electro-optical device includes a measurement circuit. Therefore, compared to the display module described in Supplementary Note 1 in which the drive circuit is arranged on the wiring substrate, the distance between the temperature detection element arranged in the electro-optical device and the measurement circuit is shorter. Therefore, compared to the display module described in Supplementary Note 1, the display module described in Supplementary Note 2 makes it possible to further improve the temperature measurement accuracy of the electro-optical device because the output signal of the temperature detection element taken into the measurement circuit is less susceptible to disturbance noise. Furthermore, in the display module described in Supplementary Note 2, as in the display module described in Supplementary Note 1, the measurement circuit measures the temperature of the electro-optical device based on the output signal of the temperature detection element during the flyback period of the electro-optical device. This makes it possible to prevent the output signal of the temperature detection element taken into the measurement circuit from being affected by power supply noise, thereby further improving the accuracy of temperature measurement of the electro-optical device.

[0092] (Supplementary Note 3) The display module according to Supplementary Note 1 or 2, wherein the blanking period is a blanking period included in a horizontal scanning period.

[0093] According to the display module described in Appendix 3, the output signal of the temperature detection element input to the measurement circuit can be prevented from being affected by power supply noise generated during the horizontal scanning period, thereby further improving the temperature measurement accuracy of the electro-optical device.

[0094] (Supplementary Note 4) The display module according to any one of Supplementary Notes 1 to 3, wherein the blanking period is a blanking period included in a vertical scanning period.

[0095] According to the display module described in Appendix 4, the output signal of the temperature detection element input to the measurement circuit can be prevented from being affected by power supply noise generated during the vertical scanning period, thereby further improving the temperature measurement accuracy of the electro-optical device.

[0096] (Appendix 5) A display module described in any one of Appendices 1 to 4, wherein the measurement circuit includes a constant current source that supplies current to the temperature detection element, an A / D converter that converts the output signal of the temperature detection element into a digital value, and a second control circuit that controls the A / D converter so that the output signal of the temperature detection element is captured by the A / D converter during the flyback period.

[0097] In the display module described in Supplementary Note 5, the distance between the temperature detection element disposed in the electro-optical device and the A / D converter included in the measurement circuit is shorter than in conventional techniques in which the measurement circuit is disposed on a circuit board. Therefore, the output signal of the temperature detection element taken into the A / D converter is less susceptible to disturbance noise compared to conventional techniques, thereby improving the temperature measurement accuracy of the electro-optical device. Furthermore, the second control circuit controls the A / D converter so that the output signal of the temperature detection element is input to the A / D converter during the flyback period of the electro-optical device, thereby preventing the output signal of the temperature detection element input to the A / D converter from being affected by power supply noise, thereby further improving the temperature measurement accuracy of the electro-optical device.

[0098] (Supplementary Note 6) The display module according to any one of Supplementary Notes 1 to 5, wherein the electro-optical device has a signal line driving circuit including a plurality of demultiplexers.

[0099] An electro-optical device that operates using a signal line driver circuit including multiple demultiplexers generates relatively large power supply noise. Therefore, by applying the display module configuration described in Supplementary Note 1 or Supplementary Note 2, the effects of power supply noise can be more effectively suppressed.

[0100] (Supplementary Note 7) The display module according to any one of Supplementary Notes 1 to 6, wherein the temperature detection element is a diode.

[0101] According to the display module described in Appendix 7, a temperature detection element can be formed in the electro-optical device together with a pixel switching element, etc., so there is no need to use other temperature detection elements such as a thermistor to detect the temperature of the electro-optical device.

[0102] (Appendix 8) An electronic device comprising a display module according to any one of appendices 1 to 7.

[0103] According to Supplementary Note 8, it is possible to provide an electric device including a display module with improved temperature measurement accuracy of an electro-optical device. [Explanation of symbols]

[0104] 1000, 2000...display module, 100, 100A...liquid crystal panel (electro-optical device), 22...temperature detection circuit, 51...diode (temperature detection element), 61...constant current source, 63...A / D converter, 64...second control circuit, 200, 200A...wiring board, 210...driver IC (drive circuit), 220...measurement circuit, 300...circuit board, 310...first control circuit, 10000...projector (electronic device)

Claims

1. an electro-optical device having a temperature detection element and displaying an image; a wiring board having a drive circuit for driving the electro-optical device; a circuit board including a first control circuit for controlling the drive circuit, the circuit board being electrically connected to the electro-optical device via the wiring board; Equipped with the drive circuit includes a measurement circuit that measures the temperature of the electro-optical device based on the output signal of the temperature detection element during a blanking period of the electro-optical device; Display module.

2. an electro-optical device having a temperature detection element and displaying an image; A wiring board; a circuit board electrically connected to the electro-optical device via the wiring board; Equipped with the electro-optical device has a drive circuit that drives the electro-optical device, the circuit board has a first control circuit that controls the drive circuit; the drive circuit includes a measurement circuit that measures the temperature of the electro-optical device based on the output signal of the temperature detection element during a blanking period of the electro-optical device; Display module.

3. 3. The display module according to claim 1, wherein the blanking period is included in a horizontal scanning period.

4. 3. The display module according to claim 1, wherein the blanking interval is included in a vertical scanning period.

5. The measurement circuit a constant current source that supplies a current to the temperature detection element; an A / D converter that converts the output signal of the temperature detection element into a digital value; a second control circuit that controls the A / D converter so that an output signal of the temperature detection element is captured by the A / D converter during the blanking period; 3. A display module according to claim 1 or 2, comprising:

6. 3. The display module according to claim 1, wherein the electro-optical device has a signal line driving circuit including a plurality of demultiplexers.

7. 3. The display module according to claim 1, wherein the temperature detection element is a diode.

8. An electronic device comprising the display module according to claim 1 or 2.

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