JP2011085619A - Electro-optical device and electronic apparatus - Google Patents

Abstract

An area required for installing a temperature sensor for detecting the temperature of an electro-optical device is reduced.
A plurality of pixel circuits P including a display pixel circuit PA and a detection pixel circuit PBa are formed on a surface of an element substrate 10B. A wiring 52 and a wiring 54 are formed on the surface of the element substrate 10B. The detection pixel circuit PBa includes a selection transistor qB (qB1, qB2) that conducts the signal line 14 and the wiring 52 when the scanning line 12 is selected. The on-current of each select transistor qB varies with temperature. A detection current IMNT for temperature detection corresponding to the current Im supplied from the wiring 52 to the signal line 14 via the selection transistor qB of the detection pixel circuit PBa is output to the wiring 54.
[Selection] Figure 1

Description

  The present invention relates to a technique for driving an electro-optical element such as a liquid crystal element.

  In an electro-optical device that displays an image using an electro-optical element such as a liquid crystal element, a variation in characteristics of the electro-optical element (for example, response speed of liquid crystal) according to the temperature of the use environment becomes a problem. Patent Document 1 discloses a technique for controlling a cooler according to a temperature detected by a temperature sensor installed in the vicinity of a display area.

JP 2000-9547 A

  However, as disclosed in FIG. 1 of Patent Document 1, it is necessary to secure a region for installing the temperature sensor separately from the display region and the formation region of the drive circuit. There is a problem that is obstructed. In view of the above circumstances, an object of the present invention is to reduce an area required for installing a temperature sensor.

  In order to solve the above problem, an electro-optical device according to a first aspect of the present invention includes a plurality of pixel circuits arranged corresponding to each intersection of a plurality of scanning lines and a plurality of signal lines, and a plurality of pixel circuits. Each of the pixel circuits includes a drive circuit (for example, the drive circuit 30 in FIG. 1), and the plurality of pixel circuits include a display pixel circuit (for example, the display pixel circuit PA in FIG. 1) and a detection pixel circuit ( For example, the display pixel circuit includes a pixel electrode (for example, the pixel electrode 22 in FIG. 2) that applies a gradation signal to an electro-optical material (for example, the liquid crystal 26 in FIG. 2). And a selection transistor (for example, the selection transistors qA1 and qA2 in FIG. 2) that conducts the pixel electrode and a signal line to which a gradation signal is supplied when the scanning line is selected, and the detection pixel circuit includes the scanning line and the signal line. Select transistor placed corresponding to the intersection with The detection for detecting the temperature according to the current flowing through the path including the selection transistor (for example, the selection transistors qB1 and qB2 in FIG. 3) whose on-current depends on the temperature and including the signal line and the selection transistor of the detection pixel circuit. Output current. In the above configuration, since the detection current is generated according to the current that has passed through each selection transistor of the detection pixel circuit whose on-current depends on the temperature, the region where the temperature sensor is installed is the display region or the drive circuit. It is not necessary to secure it separately from the formation region. Therefore, there is an advantage that the electro-optical device can be reduced in size and frame. A specific example of the first aspect will be described later as the first embodiment.

  An electro-optical device according to a preferred example of the first aspect includes a first wiring (for example, the wiring 52 in FIG. 1) to which a first potential is supplied, and a second wiring (for example, the wiring 54 in FIG. 1). The selection transistor of the detection pixel circuit makes the signal line and the first wiring conductive when the scanning line is selected, and corresponds to a current supplied from the first wiring to the signal line via the selection transistor of the detection pixel circuit. The detection current is output to the second wiring.

  In a preferred example of the electro-optical device according to the first aspect, the second potential different from the first potential is supplied to the second wiring in the display period, and the driving circuit includes a plurality of unit circuits corresponding to different signal lines. Each of the plurality of unit circuits includes a first transistor (for example, transistor TR1 in FIG. 6) interposed between the signal line and the first wiring, and a first transistor interposed between the signal line and the second wiring. Two transistors (for example, transistor TR2 in FIG. 6) and either the first transistor or the second transistor are controlled to be turned on in accordance with the designated gradation in the display period, and the second transistor is turned on in the detection period. And a control unit (for example, the control unit 62 in FIG. 6) to be controlled. In the above aspect, the second transistor used for outputting the gradation signal in the display period is used for outputting the detection current in the detection period. Therefore, there is an advantage that the configuration of the drive circuit is simplified as compared with the configuration in which the element for outputting the detection current is provided separately from the element for outputting the gradation signal.

  In a preferred example of the electro-optical device according to the first aspect, the selection transistor and the second transistor of the detection pixel circuit have the same conductivity type. In the above aspect, since the selection transistor and the second transistor that are located on the detection current path have the same conductivity type, the selection transistor and the second transistor can easily change the direction of the on-current according to the temperature. It can be made common. Therefore, there is an advantage that a sufficient amount of detection current can be ensured as compared with the configuration in which the selection transistors and the second transistors have different conductivity types.

  In a preferred example of the electro-optical device according to the first aspect, the display pixel circuit includes the display pixel circuits arranged in a matrix in the display area, and the detection pixel circuits are arranged around the display area. It does not contribute to image display. In the above aspect, since the detection pixel circuit does not directly contribute to the display of the image, there is an advantage that the detection current can be generated without affecting the display image.

  An electro-optical device according to a second aspect of the present invention includes a plurality of pixel circuits arranged corresponding to respective intersections of a plurality of scanning lines and a plurality of signal lines, each including an electro-optical element, and a temperature detecting device. A detection circuit for outputting a detection current (for example, the detection line 56 in FIGS. 10 and 14) and a drive circuit configured to include a drive transistor whose on-current depends on temperature, and driving each of the plurality of pixel circuits; And a detection current corresponding to the current passing through the driving transistor is output to the detection line. In the above configuration, the detection current is generated according to the current passing through the driving transistor in the driving circuit whose on-current depends on the temperature, so that the area where the temperature sensor is installed is formed as a display area or a driving circuit. There is no need to secure it separately from the area. Therefore, there is an advantage that the electro-optical device can be reduced in size and frame.

  The electro-optical device according to the preferred example of the second aspect (hereinafter referred to as “configuration example 1”) is different from the first wiring to which the first potential is supplied (for example, the wiring 52 in FIG. 10). The drive circuit includes a plurality of unit circuits corresponding to different signal lines, and each of the plurality of unit circuits includes a signal line. And a first transistor (for example, transistor TR1 in FIG. 12) interposed between the first wiring and the first wiring, and a second transistor (for example, transistor TR2 in FIG. 12) interposed between the signal line and the second wiring. And a control unit that controls either the first transistor or the second transistor in the display period according to the designated gradation and controls the first transistor in the detection period (for example, the control in FIG. 12). Part 66) Mu In the above aspect, the first transistor used for outputting the gradation signal in the display period is used for outputting the detection current in the detection period. Therefore, there is an advantage that the configuration of the drive circuit is simplified as compared with the configuration in which the element for outputting the detection current is provided separately from the element for outputting the gradation signal. A specific example of Configuration Example 1 will be described later as a second embodiment.

  In a preferred aspect of Configuration Example 1, each of the plurality of unit circuits includes a detection transistor (for example, the detection transistor TR3 in FIG. 12) interposed between the signal line and the detection line, and the detection transistor is in the display period. It is controlled to the off state and controlled to the on state in the detection period. In the above aspect, since the signal line and the detection line are electrically insulated in the display period, power consumption (gradation signal of the gradation signal is compared with a configuration in which the signal line is electrically connected to the detection line in the display period. This has the advantage that the amount of charge movement due to output is reduced. Further, according to the configuration in which the first transistor and the detection transistor have the same conductivity type, the direction of change of the on-current according to the temperature can be easily made common to the first transistor and the detection transistor. Therefore, there is an advantage that a sufficient amount of detection current can be ensured as compared with a configuration in which the first transistor and the detection transistor have different conductivity types.

  In the electro-optical device according to a preferred example of the second aspect (hereinafter referred to as “configuration example 2”), the drive circuit includes a precharge circuit that supplies a precharge potential to each signal line during the precharge period, and the drive transistor Constitutes a precharge circuit. In the above aspect, the control transistor used for precharging the signal line is used for outputting the detection current in the detection period. Therefore, there is an advantage that the configuration of the drive circuit is simplified as compared with the configuration in which the element for outputting the detection current is provided separately from the element for supplying the precharge potential. A specific example of the configuration example 2 will be described later as a third embodiment.

  In a preferred aspect of Configuration Example 2, the driver circuit supplies a grayscale signal corresponding to the designated grayscale to each of the plurality of signal lines in the display period, and a plurality of predetermined potentials in the detection period and the precharge period. In the precharge circuit, a control transistor that is interposed between the signal line and the detection line and that is controlled to be on during the detection period and the precharge period is used for driving. A transistor is arranged for each signal line, a current passing through each signal line and each control transistor is output to the detection line as a detection current in the detection period, and a predetermined precharge potential is output from the detection line in the precharge period. It is supplied to each signal line via the control transistor.

  The electro-optical device according to a preferred aspect of the configuration example 2 includes an image signal line (for example, the image signal line 58 in FIG. 14) to which a gradation signal is supplied in the display period and a predetermined potential is supplied in the detection period. The signal line driving circuit includes a capturing transistor (for example, the capturing transistor r1 and the capturing transistor r2 in FIG. 14) interposed between the image signal line and the signal line as a driving transistor for each signal line. Each of the acquisition transistors is controlled to be in an on state in a detection period and is sequentially controlled to be in an on state in a display period. In the detection period, each acquisition transistor, each signal line, and each control transistor The current passing through is output as a detection current to the detection line. In the above aspect, the current that has passed through the capturing transistor, the signal line, and the control transistor from the image signal line to which the predetermined potential is supplied is output to the detection line as the detection current in the detection period. Therefore, there is an advantage that the detection current can be appropriately adjusted according to the potential of the image signal line in the detection period.

  In a preferred aspect of Configuration Example 2, the detection period and the precharge period are set within the vertical blanking period. In the above aspect, since the detection period and the precharge period are set within the vertical blanking period, there is an advantage that the detection current can be generated without affecting the display image.

  The electro-optical device according to the specific example of each of the above aspects (first aspect and second aspect) includes a heater that heats each electro-optical element, and a temperature control circuit that controls the heater according to the detected current. To do. In the above aspect, since the heater is controlled in accordance with the detected current, high-quality display can be performed by maintaining the temperature of the electro-optical device (electro-optical element) within a desired range. However, the application of the detection current is not limited to temperature control.

  Note that the tendency that the current flowing through the transistor depends on temperature becomes apparent when the voltage between the gate and the source of the transistor is sufficiently higher than the threshold voltage. Therefore, the selection transistor of the detection pixel circuit in the first mode and the driving transistor of the drive circuit in the second mode gate, for example, a voltage that sufficiently exceeds each threshold voltage (for example, a voltage that exceeds twice the threshold voltage). -It is controlled to be on by being applied between the sources.

  The electro-optical device according to each aspect described above is used in various electronic apparatuses. A typical example of an electronic device is a device that uses an electro-optical device as a display device. For example, since the temperature inside the vehicle of an automobile changes greatly, the electro-optical device according to each of the above aspects in which a detection current corresponding to the temperature of the electro-optical device is output is an in-vehicle display device (for example, an instrument panel or a car navigation device). It is particularly suitable. In addition, the electro-optical device of the present invention is also suitably used for electronic devices such as mobile phones and portable information terminals.

1 is a block diagram of an electro-optical device according to a first embodiment of the invention. FIG. It is a circuit diagram of a pixel circuit (display pixel circuit). It is a circuit diagram of a pixel circuit (detection pixel circuit). It is a graph which shows the temperature dependence of the on-current of a transistor. 6 is a timing chart illustrating an operation of the electro-optical device according to the first embodiment. It is a circuit diagram of a unit circuit. It is a schematic diagram for demonstrating operation | movement of the unit circuit in a display period. It is a schematic diagram for demonstrating operation | movement of the unit circuit in a detection period. It is a block diagram of a temperature control circuit. FIG. 6 is a block diagram of an electro-optical device according to a second embodiment. 12 is a timing chart illustrating an operation of the electro-optical device according to the second embodiment. It is a circuit diagram of a unit circuit. It is a schematic diagram for demonstrating operation | movement of the unit circuit in a detection period. FIG. 10 is a block diagram of an electro-optical device according to a third embodiment. 12 is a timing chart illustrating an operation of the electro-optical device according to the third embodiment. FIG. 6 is a block diagram of an electro-optical device according to a modification of the first embodiment. FIG. 10 is a block diagram of an electro-optical device according to a modification of the second embodiment. It is a perspective view which shows the form (personal computer) of an electronic device. It is a perspective view which shows the form (cellular phone) of an electronic device. It is a perspective view which shows the form (mobile information terminal) of an electronic device.

<A: First Embodiment>
FIG. 1 is a block diagram of an electro-optical device 100A according to the first embodiment of the present invention. The electro-optical device 100A is a liquid crystal device mounted on various electronic devices as a display device for displaying an image. As shown in FIG. 1, the electro-optical device 100A includes an element unit 10 in which a plurality of pixel circuits P (PA, PB) are arranged in a plane, and a drive circuit 30 that drives each pixel circuit P. The drive circuit 30 includes a scanning line drive circuit 32 and a signal line drive circuit 34. The electro-optical device 100A includes a control circuit 42, a potential generation circuit 44, a temperature control circuit 46, and a heater 48.

  In the element unit 10, M scanning lines 12 extending in the X direction and N signal lines 14 extending in the Y direction intersecting the X direction are formed (M and N are natural numbers). The plurality of pixel circuits P are arranged corresponding to the intersections of the scanning lines 12 and the signal lines 14 and are arranged in a matrix of vertical M rows × horizontal N columns. In addition, wiring 52 and wiring 54 are formed on the surface of a substrate (hereinafter referred to as “element substrate”) 10B on which each pixel circuit P is formed.

  As shown in FIG. 1, the plurality of pixel circuits P include a plurality of display pixel circuits PA that are actually used for displaying an image and a plurality of dummy pixel circuits PB (PBa that do not directly contribute to image display. ). The plurality of display pixel circuits PA are arranged in a matrix in the rectangular display area 10A, and the plurality of dummy pixel circuits PB are arranged around the display area 10A (for example, in an area covered with a light shielding layer). . Among the plurality of dummy pixel circuits PB, N dummy pixel circuits (hereinafter, particularly referred to as “detection pixel circuits”) PBa in the M-th row are used for detecting the temperature of the electro-optical device 100A.

  FIG. 2 is a circuit diagram of each display pixel circuit PA. As shown in FIG. 2, the display pixel circuit PA includes a liquid crystal element 20 and a selection switch QA. The liquid crystal element 20 is an electro-optical element composed of a pixel electrode 22, a common electrode 24, and a liquid crystal 26 between both electrodes. The selection switch QA is an element that is interposed between the liquid crystal element 20 (pixel electrode 22) and the signal line 14 and controls electrical connection (conduction / non-conduction) between them, and is connected in series to each other. It is composed of two selection transistors qA (qA1, qA2). Each selection transistor qA is, for example, an N-channel thin film transistor (TFT) whose semiconductor layer is formed of amorphous silicon or low-temperature polysilicon. The gate of each selection transistor qA is connected to the scanning line 12.

  FIG. 3 is a circuit diagram of each dummy pixel circuit PB (detection pixel circuit PBa). Similar to the display pixel circuit PA, the dummy pixel circuit PB includes the liquid crystal element 20 and the selection switch QB. However, the liquid crystal element 20 and the selection switch QB are electrically insulated. Therefore, the liquid crystal element 20 of the dummy pixel circuit PB does not contribute to display. A configuration in which the selection switch QB of the dummy pixel circuit PB is connected to the pixel electrode 22 (however, it is covered with a light shielding layer and does not contribute to display), or the pixel electrode 22 (liquid crystal element 20) of the dummy pixel circuit PB is used. An omitted configuration is also adopted.

  As shown in FIG. 3, the selection switch QB of the dummy pixel circuit PB includes two selection transistors qB (qB1, qB2) connected in series with each other. The selection transistor qB is an N-channel thin film transistor that is collectively formed on the surface of the element substrate 10B in the same process as the selection transistor qA. As shown in FIG. 3, the selection switch QB of the detection pixel circuit PBa among the dummy pixel circuits PB is interposed between the signal line 14 and the wiring 52 to control the electrical connection therebetween. The gate of each selection transistor qB of the detection pixel circuit PBa is connected to the scanning line 12 of the Mth row.

  Part (A) of FIG. 4 is a graph showing the relationship between the temperature of the selection transistor qB (the temperature of the electro-optical device 100A) and the on-current. The on-current is a current that flows between the drain and the source when the voltage between the gate and the source exceeds the threshold voltage. As shown in part (A) of FIG. 4, the on-current of the selection transistor qB depends on the temperature of the electro-optical device 100A. Specifically, the on-current of the selection transistor qB tends to increase as the temperature increases. The selection transistor qA also exhibits similar characteristics.

  As shown in FIG. 5, each unit period (vertical scanning period) F, which is an operation cycle of the electro-optical device 100A, includes a detection period F1 and a display period F2. The detection period F1 is a period in which the temperature of the electro-optical device 100A is detected using each detection pixel circuit PBa. For example, the vertical blanking period is used as the detection period F1. On the other hand, the display period F2 is a period (vertical effective period) in which an image is actually displayed in the display area 10A by driving each display pixel circuit PA.

  The control circuit 42 in FIG. 1 generates and outputs a control signal MNT (the symbol MNT is derived from a temperature monitor) that defines the detection period F1 and the display period F2. As shown in FIG. 5, the control signal MNT is set to a high level in the detection period F1, and is set to a low level in the display period F2.

  The potential generation circuit 44 in FIG. 1 generates different potentials VH and VL. The potential VH exceeds the potential VL. The potential VH generated by the potential generation circuit 44 is supplied to the wiring 52. 1 switches the connection destination of the wiring 54 on the element substrate 10B to either the potential generation circuit 44 (output terminal of the potential VL) or the temperature control circuit 46 according to the control signal MNT. Specifically, the changeover switch 40 connects the wiring 54 to the temperature control circuit 46 in the detection period F1 in which the control signal MNT is set to a high level. On the other hand, the changeover switch 40 connects the wiring 54 to the potential generation circuit 44 in the display period F2 in which the control signal MNT is set to the low level. Therefore, as shown in FIG. 5, the potential VL is supplied to the wiring 54 in the display period F2.

  As shown in FIG. 1, the drive circuit 30 includes a scanning line drive circuit 32 and a signal line drive circuit 34. The scanning line driving circuit 32 sequentially selects the scanning lines 12 from the first row to the (M-1) th row within the display period F2 by the output of the scanning signals G [1] to G [M-1]. To do. As shown in FIG. 5, the scanning signal G [m] (m = 1 to M−1) is sequentially changed to a high level (potential meaning selection of the scanning line 12) in the display period F2. Is set. When the m-th row scanning line 12 is selected, the selection transistor qA (qA1, qA2) of each display pixel circuit PA is turned on, and the signal line 14 and the liquid crystal element 20 are brought into conduction.

  On the other hand, as shown in FIG. 1, the control signal MNT is supplied from the control circuit 42 to the scanning line 12 of the Mth row to which the N detection pixel circuits PBa are connected. Therefore, when the control signal MNT is set to a high level in the detection period F1 (that is, when the Mth row scanning line 12 is selected), the selection transistors qB (qB1, qB2) of the detection pixel circuits PBa. Transitions to the ON state, and the signal line 14 and the wiring 52 are conducted.

  The signal line driving circuit 34 in FIG. 1 outputs a detection current IMNT corresponding to the temperature of the electro-optical device 100A to the wiring 54 in the detection period F1, and a gradation signal corresponding to the gradation designated for each pixel circuit P. X [1] to X [N] are output to each signal line 14 in the display period F2. As shown in FIG. 1, the signal line drive circuit 34 includes a signal supply circuit 342 and N unit circuits UA [1] to UA [N] corresponding to different signal lines 14. The signal supply circuit 342 generates N-level gradation signals x [1] to x [N] from an image signal supplied from the outside, and outputs them in parallel. The gradation signal x [n] (n = 1 to N) when the m-th row scanning line 12 is selected is the gradation (lighted in the first embodiment) of the pixel circuit P located in the n-th column of the m-th row. Or any one of the lights off). The signal supply circuit 342 is mounted on the element substrate 10B in the form of an IC chip, for example.

  FIG. 6 is a circuit diagram of the unit circuits UA [1] to UA [N]. As shown in FIG. 6, each unit circuit UA [n] includes a control unit 62 and a signal generation unit 64. The signal generator 64 includes a transistor TR1 and a transistor TR2 interposed in series between the wiring 52 and the wiring 54. The transistor TR1 is a P-channel type thin film transistor that is interposed between the wiring 52 and the signal line 14 and controls the electrical connection therebetween. On the other hand, the transistor TR2 is an N-channel type thin film transistor that is interposed between the wiring 54 and the signal line 14 and controls the electrical connection therebetween. The transistors TR2 are collectively formed on the surface of the element substrate 10B in the same process as the transistors (qA, qB) of the pixel circuit P (however, the sizes are different). Therefore, the on-state current of the transistor TR2 exhibits the same temperature dependency as the selection transistor qA and the selection transistor qB. That is, as shown in FIG. 4B, the on-current of the transistor TR2 increases as the temperature of the electro-optical device 100A increases.

  The control unit 62 in FIG. 6 controls the signal generation unit 64 according to the control signal MNT supplied from the control circuit 42. A logical sum circuit that generates a logical sum of the control signal MNT and the gradation signal x [n] supplied from the signal supply circuit 342 as the output signal C is employed as the control unit 62. The output signal C is supplied in common to the gates of the transistors TR1 and TR2.

  As shown in FIGS. 5 and 7, since the control signal MNT is set to a low level in the display period F2, the output signal C has the same logic level as the gradation signal x [n] supplied from the signal supply circuit 342. Set to Therefore, in the display period F2, either the transistor TR1 or the transistor TR2 is controlled to be in an on state in accordance with the gradation signal x [n] (designated gradation). On the other hand, the potential VL is supplied from the potential generation circuit 44 to the wiring 54 by setting the control signal MNT to the low level. Therefore, as shown in FIG. 7, either the potential VH of the wiring 52 or the potential VL of the wiring 54 is selectively output to the signal line 14 as the gradation signal X [n]. That is, when the transistor TR1 is controlled to be on, the gradation signal X [n] is set to the potential VH, and when the transistor TR2 is controlled to be on, the gradation signal X [n] is to the potential VL. Set to The gradation signal X [n] is supplied to the pixel circuit P being selected by the scanning line driving circuit 32. Therefore, the liquid crystal element 20 of the display pixel circuit PA is controlled to a gradation (transmittance) corresponding to the gradation signal X [n].

  On the other hand, since the control signal MNT is set to the high level in the detection period F1, the output signal C generated by each control unit 62 of the unit circuits UA [1] to UA [N] is forced as shown in FIG. Is set to a high level. Therefore, the transistor TR2 of the signal generation unit 64 is controlled to be in an on state, and the transistor TR1 is controlled to be in an off state. Further, when the control signal MNT is set to the high level, the selection transistors qB (qB1, qB2) of each detection pixel circuit PBa are turned on. Therefore, as indicated by an arrow in FIG. 8, the current Im that has passed through the selection transistor qB2 and selection transistor qB1 of the detection pixel circuit PBa and the transistor TR2 of the signal generation unit 64 from the wiring 52 of the potential VH in the above order is wired. 54.

  Note that the tendency that the on-state current of the transistor depends on temperature (FIG. 4) becomes apparent when the voltage between the gate and the source of the transistor is sufficiently higher than the threshold voltage. Accordingly, the high level potential of the control signal MNT is set so that the voltage between the gate and the source of the selection transistor qB when the control signal MNT is set to the high level sufficiently exceeds its threshold voltage. For example, the voltage between the gate and the source of the selection transistor qB is set to a voltage exceeding twice the threshold voltage. For example, assuming that the threshold voltage is 1.2V, the potential of the control signal MNT is set so that the gate-source voltage of the selection transistor qB is 5V to 10V.

  As described above, since the temperature control circuit 46 is connected to the wiring 54 in the detection period F1, detection is performed by adding the current Im generated in the unit circuits UA [1] to UA [N] as shown in FIG. The current IMNT is supplied to the temperature control circuit 46 via the wiring 54 and the changeover switch 40. That is, as shown in FIG. 5, the wiring 54 is used for both the output of the detection current IMNT in the detection period F1 and the supply of the potential VL in the display period F2.

  As described with reference to part (A) and part (B) of FIG. 4, the current value of the on-current (current Im) of the selection transistor qB (qB1, qB2) and the transistor TR2 is the temperature of the electro-optical device 100A. Increases as the value rises. Therefore, as shown in FIG. 5, the current value of the detection current IMNT generated in the detection period F1 increases as the temperature of the electro-optical device 100A increases. That is, the detection current IMNT corresponds to a signal (temperature detection signal) indicating the temperature of the electro-optical device 100A.

  The temperature control circuit 46 in FIG. 1 controls the heater 48 according to the detected current IMNT supplied from the wiring 54. The heater 48 is a heater that generates heat during operation and heats the electro-optical device 100A. For example, a planar ITO (Indium Tin Oxide) heater disposed on the back side of the electro-optical device 100 </ b> A is suitably used as the heater 48. The temperature control circuit 46 activates the heater 48 to heat the electro-optical device 100A when the current value of the detection current IMNT is small (that is, when the temperature of the electro-optical device 100A is low), and the current of the detection current IMNT When the value is large, the heater 48 is stopped. Accordingly, the temperature of the electro-optical device 100A can be maintained within a predetermined range.

  FIG. 9 is a circuit diagram of the temperature control circuit 46. As shown in FIG. 9, the temperature control circuit 46 includes a current-voltage conversion circuit 72, a reference potential generation circuit 74, a comparison circuit 76, and a signal output unit 78. The current-voltage conversion circuit 72 converts the detection current IMNT into a detection potential VMNT. The current-voltage conversion circuit 72 is configured using an operational amplifier as shown in FIG. 9, for example. Therefore, as shown in FIG. 5, the detection potential VMNT decreases as the detection current IMNT increases (the temperature of the electro-optical device 100A increases). The reference potential generation circuit 74 generates a predetermined reference potential VREF. For example, the reference potential VREF is variably set according to a numerical value stored in a storage circuit (register).

  The comparison circuit 76 of FIG. 9 outputs a control signal ENB corresponding to the level of the detection potential VMNT and the reference potential VREF. Specifically, as shown in FIG. 5, when the detection potential VMNT exceeds the reference potential VREF (when the temperature of the electro-optical device 100A is low), the control signal ENB is set to a high level, and the detection potential VMNT is set to the reference potential. When the voltage is lower than VREF (when the temperature of the electro-optical device 100A is high), the control signal ENB is set to a low level.

  The signal output unit 78 generates a control signal EN_HT that instructs operation / stop of the heater 48 from the control signal ENB. Specifically, the signal output unit 78 sets the control signal EN_HT to a logic level opposite to that of the control signal ENB at the rising point of the control signal MNT (the start point of the detection period F1), and then the next time of the control signal MNT. It is a latch circuit that holds the logic level until the rising edge. Therefore, as shown in FIG. 5, in the unit period F in which the temperature of the electro-optical device 100A is so low that the detection potential VMNT exceeds the reference potential VREF, the control signal EN_HT is at a low level (a level for instructing the operation of the heater 48). In the unit period F in which the temperature of the electro-optical device 100A is high enough that the detection potential VMNT is lower than the reference potential VREF, the heater 48 is heated by setting the control signal EN_HT to the high level. The device 48 stops.

  As described above, in the first embodiment, the temperature of the electro-optical device 100A is detected by generating the detection current IMNT via the selection transistors qB (qB1, qB2) of the detection pixel circuit PBa. It is not necessary to install a temperature sensor separately from the element unit 10 and the drive circuit 30. That is, as compared with the configuration of Patent Document 1, there is an advantage that an area necessary for installation of the temperature sensor is reduced (as a result, the electro-optical device 100A can be downsized or narrowed). Further, since the selection transistor qB used to generate the detection current IMNT is close to the liquid crystal element 20, the technique of Patent Document 1 in which the temperature sensor is arranged outside the display area (that is, at a position away from the liquid crystal element). In comparison, there is an advantage that the detection current IMNT reflecting the temperature of the liquid crystal element 20 with high accuracy can be generated.

  In addition, since the unit circuits UA [1] to UA [N] of the signal line driving circuit 34 are used for both the generation of the gradation signal X [n] and the output of the detection current IMNT (current Im), the detection current IMNT There is an advantage that the configuration of the electro-optical device 100A is simplified as compared with the configuration in which the circuit for outputting and the circuit for generating the gradation signal X [n] are individually installed.

  By the way, the tendency of increase / decrease of the on-state current of the transistor with respect to temperature change (whether the on-current increases or decreases when the temperature rises) can be different depending on the characteristics (especially conductivity type) of the transistor. For example, as shown in part (C) of FIG. 4, the ON current of the P-channel transistor TR1 in the signal line driver circuit 34 tends to decrease as the temperature of the electro-optical device 100A increases. Therefore, a configuration in which the current Im passes through different conductivity type transistors (for example, a configuration in which the current Im through the N-channel type selection transistor qB of the detection pixel circuit PBa is output from the P-channel type transistor TR1 to the wiring 52. ), The increase / decrease of the current Im corresponding to the temperature is canceled out by each transistor, and it becomes difficult to sufficiently change the detection current IMNT with respect to a change in temperature. On the other hand, in the first embodiment, the selection transistor qB (qB1, qB2) located on the current Im path and the transistor TR2 have the same conductivity type, so that the variation amount of the detection current IMNT with respect to the temperature change is sufficiently large. Secured. Therefore, there is an advantage that the temperature change of the electro-optical device 100A can be detected with high accuracy. However, the conductivity type of each transistor of the electro-optical device 100A can be arbitrarily changed.

<B: Second Embodiment>
Next, a second embodiment of the present invention will be described. In the first embodiment, the detection current IMNT is generated from the current Im flowing through the selection transistor qB (qB1, qB2) of the detection pixel circuit PBa. In the second embodiment, the detection current IMNT is generated from the current passing through the transistor of the drive circuit 30 (signal line drive circuit 34). That is, the pixel circuit P is not used to generate the detection current IMNT. In the following examples, elements having the same functions and functions as those of the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted as appropriate.

  FIG. 10 is a block diagram of an electro-optical device 100B according to the second embodiment. As shown in FIG. 10, the element unit 10 includes a plurality of (vertical M rows × horizontal N columns) pixel circuits P arranged corresponding to each intersection of the scanning line 12 and the signal line 14. In the second and third embodiments, a configuration in which all the pixel circuits P in the element section 10 are display pixel circuits PA (FIG. 2) is illustrated for convenience. However, the second and third embodiments are similarly applied to the configuration in which the dummy pixel circuit PB is disposed.

  As in the first embodiment, the control circuit 42 in FIG. 10 generates and outputs a control signal MNTb that defines the detection period F1 and the display period F2. However, the control signal MNTb and the control signal MNT of the first embodiment have a relationship in which the logic level is inverted. That is, as shown in FIG. 11, the control signal MNTb is set to a low level in the detection period F1, and is set to a high level in the display period F2. The scanning line driving circuit 32 sequentially selects each of the M scanning lines 12 by the output of the scanning signals G [1] to G [M] within the display period F2 of each unit period F.

  As shown in FIG. 10, a detection line 56 for outputting a detection current IMNT is formed on the surface of the element substrate 10B separately from the wiring 52 and the wiring 54. The detection line 56 is connected to the temperature control circuit 46. A potential VL is fixedly supplied from the potential generation circuit 44 to the wiring 54. The configuration in which the potential VH is supplied to the wiring 52 is the same as in the first embodiment.

  The signal line driving circuit 34 includes a signal supply circuit 342 similar to that of the first embodiment and N unit circuits UB [1] to UB [N] corresponding to different signal lines 14. As shown in FIG. 12, each unit circuit UB [n] includes a signal generation unit 64, a control unit 66, and a detection transistor TR3. As in the first embodiment, the signal generator 64 includes a P-channel transistor TR1 interposed between the wiring 52 and the signal line 14 and an N-channel transistor interposed between the wiring 54 and the signal line 14. It comprises a transistor TR2.

  The detection transistor TR3 is a P-channel type thin film transistor formed on the surface of the element substrate 10B together with the selection transistor qA of each pixel circuit P and the transistors (TR1, TR2) of the signal generation unit 64, and the signal line 14 (transistor TR1 Between the transistor TR2 and the detection line 56 to control the electrical connection between them. A control signal MNTb is supplied from the control circuit 42 to the gate of the detection transistor TR3. Accordingly, in the detection period F1, the detection transistor TR3 is controlled to be in the on state and the detection line 56 is conducted to the signal line 14, and in the display period F2, the detection transistor TR3 is controlled to be in the off state and the detection line 56 is electrically connected to the signal line 14. Insulated.

  The detection transistor TR3 and the transistor TR1 of the signal generator 64 are collectively formed in the same process on the surface of the element substrate 10B. Therefore, the on-current of the detection transistor TR3 exhibits the same temperature dependence as the transistor TR1. That is, as shown in part (C) of FIG. 4, the on-current of the detection transistor TR3 decreases as the temperature of the electro-optical device 100B increases.

  The control unit 66 in FIG. 12 controls the signal generation unit 64 according to the control signal MNTb supplied from the control circuit 42. A logical product circuit that outputs the logical product of the control signal MNTb and the gradation signal x [n] as the output signal C is employed as the control unit 66.

  Since the control signal MNTb is set to the high level in the display period F2, the output signal C is set to the same logic level as the gradation signal x [n] supplied from the signal supply circuit 342. On the other hand, the detection transistor TR3 is maintained in the off state. Accordingly, as in the first embodiment, the gradation signal X [n] set to either the potential VH of the wiring 52 or the potential VL of the wiring 54 in accordance with the gradation signal x [n] is applied to the signal line 14. The desired image is output and displayed in the display area 10A.

  On the other hand, since the control signal MNTb is set to the low level in the detection period F1, the output signal C from the control unit 66 is forcibly set to the low level as shown in FIG. Accordingly, the transistor TR1 of the signal generation unit 64 is controlled to be in the on state, and the transistor TR2 is controlled to be in the off state. On the other hand, when the control signal MNTb is set to a low level, the detection transistor TR3 of each unit circuit UB [n] is turned on. Therefore, as indicated by an arrow in FIG. 13, the current Im from the wiring 52 of the potential VH is supplied to the detection line 56 via the transistor TR1 and the detection transistor TR3. That is, the detection current IMNT obtained by adding the current Im generated in the unit circuits UB [1] to UB [N] is supplied to the temperature control circuit 46 via the detection line 56.

  As described with reference to part (C) of FIG. 4, the on-current (Im) of the transistor TR1 and the detection transistor TR3 decreases as the temperature of the electro-optical device 100B increases. Therefore, as shown in FIG. 11, the current value of the detection current IMNT generated in the detection period F1 decreases as the temperature of the electro-optical device 100B increases. That is, the direction of change of the detection current IMNT with respect to the temperature of the electro-optical device 100B is reversed from that of the first embodiment.

  The temperature control circuit 46 is a circuit that controls the heater 48 according to the detected current IMNT, and has the same configuration as that of the first embodiment (FIG. 9). However, since the relationship between the temperature of the electro-optical device 100B and the detection current IMNT is reversed from that of the first embodiment, the signal output unit 78 of the second embodiment controls the control signal EN_HT supplied to the heater 48. It is set and held at the same logic level as that of the control signal ENB at the time when the signal MNT falls (the start point of the detection period F1). Therefore, as shown in FIG. 11, in the unit period F in which the temperature of the electro-optical device 100B is low enough that the detection potential VMNT is lower than the reference potential VREF, the heater 48 is activated by setting the control signal EN_HT to a low level. In the unit period F in which the temperature of the electro-optical device 100B is high enough that the detection potential VMNT exceeds the reference potential VREF, the control signal EN_TH is set to the high level and the heater 48 stops.

  As described above, in the second embodiment, since the temperature of the electro-optical device 100B is detected by generating the detection current IMNT via the transistor TR1 of the signal line driving circuit 34, the element unit 10 and the driving circuit 30 are detected. There is no need to install a temperature sensor separately. Therefore, similarly to the first embodiment, there is an advantage that an area necessary for installing the temperature sensor is reduced. In addition, since the transistor TR1 and the detection transistor TR3 located on the path of the current Im have the same conductivity type (the tendency of the on-current change with respect to the temperature change), similarly to the first embodiment, the detection for the temperature change is performed. A sufficient amount of fluctuation of the current IMNT is ensured. Therefore, there is an advantage that a change in temperature of the electro-optical device 100B can be detected with high accuracy. However, the conductivity type of each transistor of the electro-optical device 100B can be arbitrarily changed.

<C: Third Embodiment>
Next, a third embodiment of the present invention will be described. In the third embodiment, similarly to the second embodiment, the detection current IMNT is generated from the current passing through the transistor in the drive circuit 30. FIG. 14 is a block diagram of an electro-optical device 100C according to the third embodiment. As in the second embodiment, the element unit 10 is configured by pixel circuits P (display pixel circuit PA in FIG. 2) arranged in a matrix of vertical M rows × horizontal N columns.

  The control circuit 42 in FIG. 14 generates various signals (PRE, SEL, SMP [1] to SMP [3]) for controlling the drive circuit 30. As shown in FIG. 15, each unit period F includes a detection period F1, a display period F2, and a precharge period FPRE before the start of the display period F2 (after the detection period F1 elapses). The detection period F1 and the precharge period FPRE are set, for example, within a vertical blanking period. The display period F2 is divided into three drive periods f [1] to f [3].

  The precharge period FPRE is a period during which a predetermined precharge potential VPRE is supplied to the pixel electrode 22 and the N signal lines 14 of each pixel circuit P. The potential generation circuit 44 in FIG. 14 generates a precharge potential VPRE. The changeover switch 40 switches the connection destination of the detection line 56 on the element substrate 10B to either the potential generation circuit 44 (the output terminal of the precharge potential VPRE) or the temperature control circuit 46. Specifically, the changeover switch 40 connects the temperature control circuit 46 to the detection line 56 in the detection period F1, and connects the potential generation circuit 44 to the detection line 56 in the precharge period FPRE.

  The drive circuit 30 in FIG. 14 includes a scanning line drive circuit 32, a signal line drive circuit 34, and a precharge circuit 36. The scanning line driving circuit 32 includes a transfer circuit 322 and an output circuit 324. The transfer circuit (for example, M-stage shift register circuit) 322 generates M system transfer signals g [1] to g [M] by transfer of the start pulse. In each of the three drive periods f [1] to f [3] in the display period F2, the transfer signals g [1] to g [M] are sequentially set to a high level.

  The output circuit 324 includes M negative AND circuits 326 corresponding to the total number of scanning lines 12. The negative AND circuit 326 in the m-th row (m = 1 to M) performs a negative logical product of the transfer signal g [m] generated by the transfer circuit 322 and the all selection signal SEL generated by the control circuit 42 as the scanning signal G. [m] is output to the m-th row scanning line 12. As shown in FIG. 15, the all selection signal SEL is set to a low level during the detection period F1 and the precharge period FPRE, and is set to a high level during the display period F2 (f [1] to f [3]). The Therefore, in the detection period F1 and the precharge period FPRE, the scanning signals G [1] to G [M] are simultaneously set to the high level, and in each of the driving periods f [1] to f [3], the scanning signal G [1] to G [M] are sequentially set to a high level (M scanning lines 12 are alternatively selected in a predetermined order).

  The signal line driving circuit 34 in FIG. 14 includes a signal supply circuit 342 and N switches R corresponding to different signal lines 14. The N switches R are divided into J blocks B [1] to B [J] in units of three adjacent (R [1] to R [3]) (J = N / 3). . Specifically, in a configuration in which M pixel circuits P having common display colors (for example, red, green, and blue) are arranged in the Y direction (stripe arrangement), three columns corresponding to a plurality of different display colors are used as a unit. N switches R are divided into blocks B [1] to B [J]. As shown in FIG. 14, each of the three switches R [1] to R [3] in the block B [j] includes J image signal lines 58 connected to the output terminal of the signal supply circuit 342. Among these, the j-th image signal line 58 is interposed between the signal line 14 corresponding to the switch R [k] (k = 1 to 3), and the electrical connection between them is controlled.

  As shown in FIG. 15 (switch R input), the signal supply circuit 342 supplies a predetermined potential V0 to the J image signal lines 58 in the detection period F1 and the precharge period FPRE, and J in the display period F2. The gradation signals x [1] to x [J] are supplied to the image signal lines 58 in parallel. The gradation signal x [j] is supplied to each of the M pixel circuits P corresponding to the switch R [k] of the block B [j] in the driving period f [k] in the display period F2. It is a signal that designates gradation in time division.

  As shown in FIG. 14, each switch R is a transfer gate composed of an N-channel capture transistor r1 and a P-channel capture transistor r2. The capturing transistor r1 and the capturing transistor r2 are constituted by thin film transistors formed together with the selection transistor qA (qA1, qA2) of the pixel circuit P. The selection signal SMP [k] is supplied from the control circuit 42 to the transistor r1 for taking in the switch R [k] in each of the blocks B [1] to B [J], and for taking in the switch R [k]. A signal obtained by inverting the selection signal SMP [k] by the inverting circuit 68 is supplied to the transistor r2.

  As shown in FIG. 15, the selection signals SMP [1] to SMP [3] are simultaneously set to a high level (a level for controlling the switch R to be on) in the detection period F1. Accordingly, in the detection period F1, the N switches R are simultaneously turned on, and the potential V0 output from the signal supply circuit 342 to the image signal line 58 is supplied to the N signal lines 14 in parallel. In the precharge period FPRE, the selection signals SMP [1] to SMP [3] are set to the low level, so that the N switches R are maintained in the off state.

  The selection signals SMP [1] to SMP [3] are alternatively set to a high level in a predetermined order during the display period F2. That is, the selection signal SMP [k] is set to a high level during the driving period f [k] within the display period F2. Therefore, in the driving period f [k], the gradation signal X [n] for designating the gradation in synchronization with the selection of each scanning line 12 in the driving period f [k] is the blocks B [1] to B [B]. [J] is output to the signal line 14 via the switch R [k]. That is, the voltage of the liquid crystal element 20 of each pixel circuit P is set according to the designated gradation in the driving periods f [1] to f [3] within the display period F2.

  The precharge circuit 36 of FIG. 14 is configured to include N control transistors S [1] to S [N] corresponding to different signal lines 14. Each of the control transistors S [1] to S [N] is an N-channel type thin film transistor formed on the surface of the element substrate 10B together with the selection transistor qA (qA1, qA2) of the pixel circuit P. The nth control transistor S [n] is interposed between the signal line 14 and the detection line 56 in the nth column and controls the electrical connection between them. A control signal PRE is supplied from the control circuit 42 to each gate of the control transistors S [1] to S [N]. As shown in FIG. 15, the control signal PRE is set to a high level during the detection period F1 and the precharge period FPRE, and is set to a low level during the display period F2.

  As described above, in the precharge period FPRE, the control transistors S [1] to S [N] are controlled to be in the on state and the switch R is controlled to be in the off state. A precharge potential VPRE is supplied. Therefore, the precharge potential VPRE is supplied to each signal line 14. Further, since the scanning signals G [1] to G [M] are set to a high level in the precharge period FPRE, the precharge potential VPRE is supplied to the pixel electrodes 22 in all the pixel circuits P in the element section 10. .

  On the other hand, in the detection period F1, N switches R (r1, r2) and N control transistors S [1] to S [S] with the potential V0 supplied from the signal supply circuit 342 to each image signal line 58. Since [N] is controlled to be in the ON state, as shown by an arrow in FIG. 14 for the first column, it passes through the capturing transistor r1, the capturing transistor r2, the signal line 14, and the control transistor S [n]. The current Im thus supplied is supplied to the detection line 56 for each column. Since the temperature control circuit 46 is connected to the detection line 56 in the detection period F 1, the detection current IMNT obtained by adding the current Im of each column is supplied to the temperature control circuit 46 via the detection line 56. That is, as shown in FIG. 15, the detection line 56 is used for both the output of the detection current IMNT in the detection period F1 and the supply of the precharge potential VPRE in the precharge period FPRE.

  In the capture transistor r1 of each switch R and the control transistor S [n] of the precharge circuit 36, as shown in part (B) of FIG. 4, the on-current tends to increase as the temperature rises. . On the other hand, the on-current of the capture transistor r2 of each switch R decreases as the temperature rises, as shown in part (C) of FIG. The current Im passes through both the N-channel type transistor (r1, S [n]) and the P-channel type transistor (r2), but there are many N-channel type transistors on the path of the current Im. The detection current IMNT (current Im) increases as the current rises. Accordingly, as in the first embodiment, the temperature control circuit 46 controls the heater 48 according to the detection current IMNT, so that the temperature of the electro-optical device 100C is maintained within a predetermined range.

  As described above, in the third embodiment, the detection current IMNT that has passed through the capture transistor r1 and capture transistor r2 of the signal line drive circuit 34 and the control transistor S [n] of the precharge circuit 36. Since the temperature of the electro-optical device 100C is detected by generating the above, there is an advantage that the area necessary for installing the temperature sensor is reduced as in the first embodiment. The conductivity type of each transistor of the electro-optical device 100C can be arbitrarily changed.

<D: Modification>
Each of the above forms can be variously modified. Specific modifications are exemplified below. Two or more aspects arbitrarily selected from the following examples can be appropriately combined.

(1) Modification 1
A configuration in which the signal line driving circuit 34 is disposed on both ends of the signal line 14 (regions facing each other across the display region) is also employed. For example, FIG. 16 shows a configuration in which the signal line drive circuit 34 of the first embodiment is arranged on both ends of the signal line 14 as a signal line drive circuit 34A and a signal line drive circuit 34B. In addition to the N dummy pixel circuits PB in the Mth row, the N dummy pixel circuits PB in the first row are also used as the detection pixel circuit PBa. That is, the detection current IMNT composed of the current Im passing through the selection transistor qB (qB1, qB2) of each detection pixel circuit PBa in the Mth row and each transistor TR2 in the signal line driving circuit 34A, and each of the first row The temperature control circuit 46 is supplied with an addition current with the detection current IMNT constituted by the current Im via the selection transistor qB (qB1, qB2) of the detection pixel circuit PBa and each transistor TR2 of the signal line drive circuit 34B.

  Similarly, FIG. 17 shows a configuration in which the signal line drive circuit 34 of the second embodiment is arranged on both ends of the signal line 14 as a signal line drive circuit 34A and a signal line drive circuit 34B. A detection current IMNT composed of a current passing through each transistor TR1 and each detection transistor TR3 in the signal line driving circuit 34A, and a detection composed of a current passing through each transistor TR1 and each detection transistor TR3 in the signal line drive circuit 34B. An addition current with the current IMNT is supplied to the temperature control circuit 46. 16 and 17 has an advantage that a sufficient amount of current (variation width according to temperature) of the detection current IMNT can be ensured as compared with the first and second embodiments.

(2) Modification 2
Elements of the drive circuit 30 that are used to generate the detection current IMNT are not limited to the signal line drive circuit 34 and the precharge circuit 36. For example, a configuration in which the detection current IMNT is generated from the current passing through the transistor of the scanning line driving circuit 32 is also employed. That is, the second embodiment and the third embodiment are included as a configuration that generates the detection current IMNT according to the current that has passed through the drive transistor included in the drive circuit 30 that is used to drive the pixel circuit P. The transistor TR1 and the detection transistor TR3 of the second embodiment, and the capture transistors (r1, r2) and the control transistor S [n] of the third embodiment are examples of driving transistors. The conductivity type of the driving transistor is arbitrary.

(3) Modification 3
In each of the above embodiments, the detection current IMNT is generated for each unit period F, but the timing for generating the detection current IMNT (the timing for setting the detection period F1) is arbitrarily changed. For example, a configuration in which the detection current IMNT is generated with a plurality of unit periods F as a cycle is employed. However, the configuration in which the detection current IMNT is periodically generated is not essential. For example, the detection current IMNT is generated in response to a user operation on the input device, or in a predetermined period immediately after the electro-optical device 100 (100A, 100B, 100C) is turned on. The structure to do may also be adopted.

(4) Modification 4
In each of the above embodiments, the detection current IMNT is used for controlling the heater 48, but the use of the detection current IMNT (result of detecting the temperature of the electro-optical device 100) is arbitrary. For example, a configuration in which the gradation signal X [n] is corrected according to the detection current IMNT so that a change in gradation of each liquid crystal element 20 according to the temperature of the electro-optical device 100 is compensated, or the electro-optical device 100 is provided. A configuration in which the cooler to be cooled is controlled in accordance with the detected current IMNT can also be adopted.

(5) Modification 5
In the third embodiment, each scanning line 12 is selected in the precharge period FPRE, but the scanning line 12 is not selected in the precharge period FPRE (that is, the precharge potential VPRE is supplied only to each signal line 14). Configuration) can also be employed.

(6) Modification 6
The liquid crystal element 20 is merely an example of an electro-optical element. The electro-optical element applied to the present invention is driven by the distinction between a self-luminous type that emits light itself and a non-luminous type (for example, a liquid crystal element) that changes the transmittance and reflectance of external light, and is driven by current supply. The distinction between the current drive type and the voltage drive type driven by application of an electric field (voltage) is unquestioned. For example, organic EL element, inorganic EL element, LED (Light Emitting Diode), field electron emission element (FE (Field-Emission) element), surface conduction electron emission element (SE (Surface conduction Electron emitter) element), ballistic electron The present invention is applied to an electro-optical device using various electro-optical elements such as a emitting element (BS (Ballistic electron Emitting) element), an electrophoretic element, and an electrochromic element. That is, the electro-optic element is an electro-optic material (for example, liquid crystal 26) whose gradation (optical characteristics such as transmittance and luminance) changes in accordance with an electrical action such as supply of current or application of voltage (electric field). As a driven element (typically, a display element whose gray scale is controlled according to a gray scale signal).

<E: Application example>
Next, electronic devices using the electro-optical device 100 (100A, 100B, 100C) according to each of the above embodiments will be described. 18 to 20 show forms of electronic devices that employ the electro-optical device 100 as a display device.

  FIG. 18 is a perspective view illustrating the configuration of a portable personal computer that employs the electro-optical device 100. The personal computer 2000 includes an electro-optical device 100 that displays various images, and a main body 2010 on which a power switch 2001 and a keyboard 2002 are installed.

  FIG. 19 is a perspective view illustrating a configuration of a mobile phone to which the electro-optical device 100 is applied. The cellular phone 3000 includes a plurality of operation buttons 3001 and scroll buttons 3002, and the electro-optical device 100 that displays various images. By operating the scroll button 3002, the screen displayed on the electro-optical device 100 is scrolled.

  FIG. 20 is a perspective view illustrating a configuration of a personal digital assistant (PDA) to which the electro-optical device 100 is applied. The portable information terminal 4000 includes a plurality of operation buttons 4001, a power switch 4002, and the electro-optical device 100 that displays various images. When the power switch 4002 is operated, various information such as an address book and a schedule book are displayed on the electro-optical device 100.

  Note that electronic devices to which the electro-optical device according to the present invention is applied include the projectors, digital still cameras, televisions, video cameras, car navigation devices, and in-vehicle displays as well as the devices illustrated in FIGS. (Instrument panel), electronic notebook, electronic paper, calculator, word processor, workstation, videophone, POS terminal, printer, scanner, copier, video player, equipment equipped with a touch panel, and the like.

100A, 100B, 100C: electro-optical device, 10: element portion, 12: scanning line, 14: signal line, 10A: display area, PA: display pixel circuit, PB: dummy pixel circuit, PBa: detection pixel circuit, qA1, qA2, qB1, qB2 ... selection transistor, 20 ... liquid crystal element, 30 ... drive circuit, 32 ... scanning line drive circuit, 34 ... signal line drive circuit, UA [ 1] to UA [N], UB [1] to UB [N]... Unit circuit, 62, 66... Control unit, 64... Signal generation unit, TR1, TR2. R (R [1] to R [3])... Switch, r1, r2... Capture transistor, 36... Precharge circuit, S [1] to S [N]. Changeover switch 42... Control circuit 44... Potential generation circuit 46... Temperature control circuit 48. ... Wiring, 56... Detection line, 58... Image signal line, 62 and 66.

Claims (15)

A plurality of pixel circuits arranged corresponding to each intersection of the plurality of scanning lines and the plurality of signal lines;
A drive circuit for driving each of the plurality of pixel circuits,
The plurality of pixel circuits include a display pixel circuit and a detection pixel circuit,
The display pixel circuit includes:
A pixel electrode for applying a gradation signal to the electro-optic material;
A selection transistor for conducting the pixel electrode and the signal line to which the gradation signal is supplied when the scanning line is selected,
The detection pixel circuit includes:
A selection transistor disposed corresponding to an intersection of the scanning line and the signal line, the selection transistor having an on-current dependent on temperature;
An electro-optical device that outputs a detection current for temperature detection corresponding to a current flowing through a path including the signal line and the selection transistor of the detection pixel circuit. A first wiring to which a first potential is supplied;
Second wiring,
The selection transistor of the detection pixel circuit makes the signal line and the first wiring conductive when the scanning line is selected,
The electro-optical device according to claim 1, wherein the detection current corresponding to a current supplied from the first wiring to the signal line via the selection transistor of the detection pixel circuit is output to the second wiring. A second potential different from the first potential is supplied to the second wiring in a display period;
The drive circuit includes a plurality of unit circuits corresponding to the different signal lines,
Each of the plurality of unit circuits is
A first transistor interposed between the signal line and the first wiring;
A second transistor interposed between the signal line and the second wiring;
A control unit configured to control any one of the first transistor and the second transistor in an on state in the display period according to a specified gradation and to control the second transistor in an on state in a detection period. Item 2. The electro-optical device according to Item 2. The electro-optical device according to claim 3, wherein the selection transistor and the second transistor of the detection pixel circuit have a common conductivity type. The display pixel circuit includes:
Each of the display pixel circuits is arranged in a matrix in a display area,
The electro-optical device according to claim 1, wherein the detection pixel circuit is arranged around the display area and does not contribute to image display. A plurality of pixel circuits each disposed corresponding to each intersection of the plurality of scanning lines and the plurality of signal lines and each including an electro-optic element;
A detection line for outputting a detection current for temperature detection;
A driving circuit configured to include a driving transistor whose on-current depends on temperature and driving each of the plurality of pixel circuits;
An electro-optical device that outputs the detection current corresponding to the current passing through the driving transistor to the detection line. A first wiring to which a first potential is supplied;
A second wiring to which a second potential different from the first potential is supplied;
The drive circuit includes a plurality of unit circuits corresponding to the different signal lines,
Each of the plurality of unit circuits is
A first transistor interposed as the driving transistor between the signal line and the first wiring;
A second transistor interposed between the signal line and the second wiring;
And a control unit configured to control any one of the first transistor and the second transistor to an on state in a display period according to a specified gradation and to control the first transistor to an on state in a detection period. 6. An electro-optical device. Each of the plurality of unit circuits includes a detection transistor interposed between the signal line and the detection line,
The electro-optical device according to claim 7, wherein the detection transistor is controlled to be in an off state during the display period and is controlled to be in an on state during the detection period. The electro-optical device according to claim 8, wherein the first transistor and the detection transistor have a common conductivity type. The drive circuit includes a precharge circuit that supplies a precharge potential to each signal line in a precharge period;
The electro-optical device according to claim 6, wherein the driving transistor constitutes the precharge circuit. The drive circuit is
A signal line driving circuit for supplying a gradation signal corresponding to a specified gradation to each of the plurality of signal lines in a display period and supplying a predetermined potential to the plurality of signal lines in a detection period and a precharge period; Including
In the precharge circuit, a control transistor that is interposed between the signal line and the detection line and is controlled to be turned on in the detection period and the precharge period is provided as the driving transistor for each signal line. Arranged,
A current passing through each signal line and each control transistor is output to the detection line as the detection current in the detection period, and a predetermined precharge potential is output from the detection line to the control line in the precharge period. The electro-optical device according to claim 10, wherein the electro-optical device is supplied to each signal line via a transistor. An image signal line to which a gradation signal is supplied in the display period and the predetermined potential is supplied in the detection period;
The signal line driving circuit includes a capturing transistor interposed between the image signal line and the signal line as the driving transistor for each signal line,
Each of the capture transistors is controlled to be in an on state in the detection period and sequentially in an on state in the display period,
The electro-optical device according to claim 11, wherein a current that has passed through each of the capturing transistors, each of the signal lines, and each of the control transistors is output to the detection line as the detection current in the detection period. The electro-optical device according to claim 11, wherein the detection period and the precharge period are set within a vertical blanking period. A heater for heating each electro-optic element;
The electro-optical device according to claim 1, further comprising: a temperature control circuit that controls the heater according to the detection current. An electronic apparatus comprising the electro-optical device according to claim 1.

Images