Light-emitting device, display device, photoelectric conversion device, electronic appliance, illumination device, and mobile body

Abstract

To provide a technique advantageous in suppressing the decrease in display quality.SOLUTION: A light-emitting device includes a pixel including a current path including a light-emitting element and a driving transistor to supply current according to a luminance signal to the light-emitting element, and a capacitor element disposed between a gate and a source of the driving transistor. The pixel further includes a first switching transistor disposed between a first power source line that supplies current to the light-emitting element and the current path, and a second switching transistor disposed between a second power source line that supplies current to the light-emitting element and the current path. The potential of the first power source line and the potential of the second power source line are different.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a light-emitting device, a display device, a photoelectric conversion device, an electronic device, a lighting device, and a moving object. [Background technology]

[0002] Patent document 1 shows a pixel including a drive transistor that drives a light-emitting element in response to a video signal, a switching transistor that supplies a drive current to the drive transistor, and a capacitive element connected between the gate electrode and source electrode of the drive transistor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2010-145579 A Summary of the Invention [Problem to be solved by the invention]

[0004] If the characteristics of elements such as transistors and capacitive elements arranged in pixels vary between pixels, the display quality may deteriorate. A configuration is required that can suppress deterioration in display quality even when the characteristics of elements vary.

[0005] An object of the present invention is to provide a technique that is advantageous in suppressing degradation of display quality. [Means for solving the problem]

[0006] In view of the above problems, a light-emitting device according to an embodiment of the present invention is a light-emitting device comprising a pixel including a light-emitting element, a current path including a driving transistor for supplying a current to the light-emitting element in accordance with a luminance signal, and a capacitive element arranged between a gate and a source of the driving transistor, wherein the pixel further includes a first switching transistor arranged between a first power supply line that supplies a current to the light-emitting element and the current path, and a second switching transistor arranged between a second power supply line that supplies a current to the light-emitting element and the current path, and wherein a potential of the first power supply line and a potential of the second power supply line are different from each other. Effect of the Invention

[0007] According to the present invention, it is possible to provide a technique that is advantageous in suppressing deterioration of display quality. [Brief description of the drawings]

[0008] [Figure 1] 1 is a diagram showing a configuration example of a light emitting device according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a circuit diagram showing a configuration example of a pixel arranged in the light-emitting device of FIG. [Diagram 3] 3 is a graph showing the Vsig-Id characteristics of a driving transistor of the pixel in FIG. 2; [Figure 4] 3 is a graph showing the Vsig-Id characteristics of a driving transistor of the pixel in FIG. 2; [Diagram 5] 3 is a timing chart showing an example of the operation of the pixel in FIG. 2; [Figure 6] FIG. 3 is a plan view showing an example of the configuration of the pixel in FIG. 2; [Figure 7] FIG. 3 is a plan view showing an example of the configuration of the pixel in FIG. 2; [Figure 8] FIG. 2 is a diagram showing a modification of the light emitting device in FIG. [Figure 9] 9 is a circuit diagram showing a configuration example of a pixel arranged in the light-emitting device of FIG. 8. [Figure 10] 9 is a circuit diagram showing a configuration example of a pixel arranged in the light-emitting device of FIG. 8. [Figure 11] FIG. 2 is a cross-sectional view showing a configuration example of a pixel of the light emitting device according to the embodiment. [Figure 12] FIG. 1 is a diagram showing an example of an image forming apparatus using a light emitting device according to an embodiment of the present invention. [Figure 13] FIG. 1 is a diagram showing an example of a display device using the light-emitting device of this embodiment. [Figure 14] FIG. 1 is a diagram showing an example of a photoelectric conversion device using a light emitting device according to an embodiment of the present invention. [Figure 15] 1A to 1C are diagrams illustrating examples of electronic devices using the light-emitting device of this embodiment. [Figure 16] FIG. 1 is a diagram showing an example of a display device using the light-emitting device of this embodiment. [Figure 17] FIG. 1 is a diagram showing an example of a lighting device using the light-emitting device of the present embodiment. [Figure 18] FIG. 1 is a diagram showing an example of a moving object using the light emitting device of the present embodiment. [Figure 19] FIG. 1 is a diagram showing an example of a wearable device using the light emitting device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] A light-emitting device according to an embodiment of the present disclosure will be described with reference to Figs. 1 to 10. In the embodiment described below, an organic electroluminescence (EL) element is arranged as a light-emitting element in a pixel included in the light-emitting device, and a driving transistor for supplying a current according to a luminance signal to the light-emitting element is connected to the anode of the light-emitting element. In addition, a case where all the transistors arranged in the pixel are P-type (P-channel type) transistors will be described. However, the pixel configuration is not limited to this. For example, the polarity and conductivity type may all be reversed. Also, for example, the driving transistor may be a P-type transistor and the other transistors may be N-type transistors, and the potential and connection supplied may be changed appropriately according to the combination of polarity and conductivity type. In addition, the light-emitting element is not limited to an organic EL element, and may be an inorganic EL element, a semiconductor laser element, a light-emitting diode (LED), or the like.

[0011] FIG. 1 is a block diagram showing a configuration example of a light emitting device 101 of the present embodiment. As shown in FIG. 1, the light emitting device 101 includes a pixel array section 103 and a driving section arranged around the pixel array section 103. A plurality of pixels 102 are arranged in the pixel array section 103 so as to form rows and columns. Each pixel 102 includes a light emitting element 201, which will be described later with reference to FIG. 2. As described above, the light emitting element 201 may be an organic EL element, and may include an organic layer (organic EL layer) including a light emitting layer between anode and cathode electrodes. The organic layer may include one or more of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer, as appropriate, in addition to the light emitting layer.

[0012] The light emitting device 101 includes a driving unit for driving each pixel 102. In the configuration shown in FIG. 1, a vertical scanning circuit 104 and a signal output circuit 105 are arranged as the driving unit. In the pixel array section 103, scanning lines 106, 107, and 108 are arranged in the row direction (horizontal direction in FIG. 1) from the vertical scanning circuit 104 so as to correspond to each pixel row of the pixels 102 arranged in the pixel array section 103. In addition, a signal line 109 is arranged in the column direction (vertical direction in FIG. 1) from the signal output circuit 105 so as to correspond to each pixel column of the pixels 102 arranged in the pixel array section 103. The scanning lines 106, 107, and 108 are connected to output terminals of the corresponding rows of the vertical scanning circuit 104. The signal line 109 is connected to output terminals of the corresponding columns of the signal output circuit 105.

[0013] The vertical scanning circuit 104 supplies a write control signal to a scanning line 106 when writing a luminance signal to each pixel 102 arranged in the pixel array unit 103. The vertical scanning circuit 104 also supplies a light emission control signal to a scanning line 107 and a scanning line 108 for controlling the on / off of light emission of a light emitting element 201 arranged in the pixel 102. The signal output circuit 105 outputs a signal voltage Vsig corresponding to the luminance signal to a signal line 109.

[0014] FIG. 2 is a diagram showing an example of the circuit configuration of each pixel 102 arranged in the light emitting device 101. The pixel 102 includes a light emitting element 201, a current path 210 including a driving transistor 202 for supplying a current corresponding to a luminance signal to the light emitting element 201, and a capacitance element 206 arranged between the gate and source of the driving transistor 202. The drain of the driving transistor 202 is connected to the anode of the two electrodes of the light emitting element 201. The cathode of the two electrodes of the light emitting element 201 is connected to a power line 213. A potential VSS is supplied to the power line 213. Furthermore, the pixel 102 includes a switching transistor 204 arranged between the power line 211 that supplies a current to the light emitting element 201 and the current path 210, and a switching transistor 205 arranged between the power line 212 that supplies a current to the light emitting element 201 and the current path 210.

[0015] A potential VDD1 is supplied to the power supply line 211. A potential VDD2 is supplied to the power supply line 212. The potential VDD1 supplied to the power supply line 211 and the potential VDD2 supplied to the power supply line 212 can be set independently of each other. In other words, the potential VDD1 of the power supply line 211 and the potential VDD2 of the power supply line 212 are different from each other. The potential VDD1 supplied to the power supply line 211 and the potential VDD2 supplied to the power supply line 212 can be higher than the potential VSS supplied to the power supply line 213.

[0016] The pixel 102 also includes a write transistor 203 for writing a signal voltage Vsig of a luminance signal to the gate of the drive transistor 202. The drain of the write transistor 203 is connected to the gate of the drive transistor 202, and the source of the write transistor 203 is connected to a signal line 109. The gate of the write transistor 203 is connected to a scanning line 106.

[0017] The capacitive element 206, as described above, is connected between the gate and source of the driving transistor 202. The capacitive element 206 may, for example, comprise a Metal-Insulator-Metal (MIM) structure.

[0018] 3 is a diagram showing the relationship between the signal voltage Vsig supplied to the gate of the driving transistor 202 from the signal line 109 via the writing transistor 203 and the drain current Id flowing through the driving transistor 202 (hereinafter, sometimes referred to as Vsig-Id characteristics). The drain current Id flowing through the driving transistor 202 is a current flowing through a current path 210, and the light emission brightness of the light emitting element 201 is controlled by this drain current Id. A solid line 301 shows the drain current Id of the driving transistor 202 with respect to the signal voltage Vsig when the capacitance value of the capacitive element 206 is the capacitance value C1. Here, the vertical axis showing the current value of the drain current Id is expressed logarithmically. In addition, in the characteristics shown in FIG. 3, a description will be given assuming that a current flows from the power supply line 211 via the switching transistor 204.

[0019] In the plane of the pixel array unit 103, the capacitance value of the capacitive element 206 may vary from row to row. When the capacitance value of the capacitive element 206 is low, the potential applied to the gate of the driving transistor 202 is lower than that of a pixel having a high capacitance value of the capacitive element 206 due to charge injection when the writing transistor 203 is turned from an on (conducting) state to an off (non-conducting) state. As a result, the gate-source voltage Vgs of the driving transistor 202 is lowered, and the drain current Id is lowered. The two-dot chain line 302 shows the Vsig-Id characteristic when the capacitance value of the capacitive element 206 is a capacitance value C2 lower than the capacitance value C1. When an arbitrary signal voltage V1 is written to the pixel 102 as the signal voltage Vsig, if the capacitance value of the capacitive element 206 is the capacitance value C1, the drain current Id of the driving transistor 202 becomes the drain current I1. On the other hand, when the capacitance value of the capacitive element 206 is the capacitance value C2, the drain current Id of the driving transistor 202 becomes the drain current I2, which is smaller than the drain current I1. In this way, the variation in the capacitance value of the capacitive element 206 causes a difference in the amount of the drain current Id flowing from the driving transistor 202.

[0020] 3 shows the Vsig-Id characteristic when a current is supplied to the light emitting element 201 from the power line 211 as described above. Meanwhile, FIG. 4 shows the Vsig-Id characteristic when a current flows from the power line 212 via the switching transistor 205 in addition to the Vsig-Id characteristic shown in FIG. 3. A dotted line 401 shows the Vsig-Id characteristic of the drive transistor 202 when the light emitting element 201 is operated from the power line 212 via the switching transistor 205 when the capacitance value of the capacitive element 206 is the capacitance value C2. The potential VDD2 supplied to the power line 212 is set higher than the potential VDD1 supplied to the power line 211. In other words, the potential VDD1 of the power line 211 is lower than the potential VDD2 of the power line 212. When the capacitance value C1 is larger than the capacitance value C2 (C1>C2), a current flows from the power line 212 with a potential higher than that of the power line 211 when the light emitting element 201 is caused to emit light. This causes the source potential Vs of the driving transistor 202 to change from potential VDD1 to potential VDD2, thereby increasing the gate-source voltage Vgs of the driving transistor 202. As a result, when the signal voltage V1 is written to the pixel 102, the drain current Id of the driving transistor 202 becomes the drain current I3. In other words, compared to when a current is flowed from the power supply line 211, the drain current Id of the driving transistor 202 increases.

[0021] In this way, in a light emission period in which the light emitting element 201 emits light, a current may be supplied from the power supply line 211 or the power supply line 212 to each of the light emitting elements arranged in the plurality of pixels 102 for each row. The vertical scanning circuit 104 supplies a light emission control signal for turning on the light emission of the light emitting element 201 via the scanning lines 107 and 108, so that the switching transistor 204 or the switching transistor 205 arranged in each pixel 102 is turned on for each row during the light emission period. A current is passed from the different power supply line 211 or the power supply line 212 for each row according to the capacitance value of the capacitance element 206 arranged in each pixel 102. This suppresses the row-to-row difference in the drain current Id of the driving transistor 202 caused by the variation in the capacitance value of the capacitance element 206, thereby realizing a high-quality display.

[0022] During the light emission period, when the pixels 102 arranged in the pixel array unit 103 are connected to the power supply line 211 or the power supply line 212 for each row, the capacitance value of the capacitive element 206 for each row is acquired in advance. Then, it may be determined which of the switching transistors 204 or the switching transistors 205 will be turned on during the light emission period, and this may be incorporated into an operation program for operating the light emitting device 101. This determination may be made, for example, by comparing an average value of the individual capacitance values ​​of the capacitive elements 206 for each row with a predetermined threshold value. Also, for example, the determination may be made by selecting the switching transistors 204 and 205 that will be turned on during the light emission period according to the number of capacitive elements 206 that exceed (or fall below) a predetermined capacitance value. The acquisition and determination of the capacitance value may be made, for example, in an inspection process before shipment from a factory. Also, for example, it may be made in a calibration process when the light emitting device 101 is used. In this case, the light emitting device 101 may include a measurement circuit for measuring the capacitance value of the capacitive element 206 or comparing it with a predetermined threshold value.

[0023] Also, for example, as shown in FIG. 1, the light emitting device 101 may include a control circuit 110 and a memory 111. The memory 111 stores capacitance data based on the capacitance value of the capacitance element 206. The capacitance data may be, for example, the capacitance value of each of the capacitance elements 206 included in the pixels 102 arranged in the pixel array unit 103. Also, for example, the capacitance data may be an average value of the capacitance values ​​of the capacitance elements 206 for each row included in the pixels 102 arranged in the pixel array unit 103. Furthermore, for example, the capacitance data may be data of "0" or "1" according to the capacitance value of each row of the capacitance elements 206 included in the pixels 102 arranged in the pixel array unit 103. For example, when the capacitance data is "0", the control circuit 110 turns on the switching transistor 204 during the light emission period, and when the capacitance data is "1", turns on the switching transistor 205 during the light emission period. During the light emission period, the control circuit 110 controls, according to the capacitance data, so that a current is supplied from the power supply line 211 or the power supply line 212 for each row to each of the light emitting elements 201 arranged in the multiple pixels 102. Consider a case in which the potential VDD1 of the power supply line 211 is lower than the potential VDD2 of the power supply line 212, and the capacitance value C1 of the capacitance element 206 of the pixel arranged in the first row among the multiple pixels 102 (which may be, for example, an average value of the capacitance values ​​of the capacitance elements 206 of the pixels 102 arranged in the first row) is larger than the capacitance value C2 of the capacitance element 206 of the pixel arranged in the second row among the multiple pixels 102 (which may be, for example, an average value of the capacitance values ​​of the capacitance elements 206 of the pixels 102 arranged in the second row). In this case, during the light emission period, the control circuit 110 can control, in accordance with the capacitance data, so that a current is supplied from the power supply line 211 to the light emitting element 201 of the pixel arranged in the first row among the multiple pixels 102, and a current is supplied from the power supply line 212 to the light emitting element 201 of the pixel arranged in the second row among the multiple pixels 102.

[0024] 1 shows an example in which the control circuit 110 and the memory 111 are arranged in the light emitting device 101, but the present invention is not limited to this. For example, the light emitting device 101 includes the memory 111 that stores capacitance data, and when the light emitting device 101 is operated, the capacitance data is read from the memory 111 to a control circuit external to the light emitting device 101. Next, the external control circuit may determine, according to the read capacitance data, a row for which the switching transistor 204 is to be turned on and a row for which the switching transistor 205 is to be turned on during the light emission period.

[0025] In the above, the operation of supplying a current to the light emitting element from the power line 211 or the power line 212 during the light emission period when the power lines 211 and 212 are arranged at different potentials and the capacitance value of the capacitive element 206 varies has been described. However, the effect of arranging the power lines 211 and 212 at different potentials that supply a current to the light emitting element 201 is not limited to the operation during the light emission period described above. Next, the operation during the write period in which the write transistor 203 is conductive and the signal voltage Vsig of the luminance signal is written to the gate of the drive transistor 202 will be described.

[0026] FIG. 5 is a timing diagram showing an example of the operation of the light emitting device 101 of this embodiment. FIG. 5 shows a write control signal input to the gate of the write transistor 203 via the scanning line 106, a light emission control signal input to the gate of the switching transistor 204 via the scanning line 107, and a light emission control signal input to the gate of the switching transistor 205 via the scanning line 108. As described above, the write transistor 203 and the switching transistors 204 and 205 are P-type transistors, so that they are turned off when the signal level is "H" and turned on when the signal level is "L". FIG. 5 also shows the voltage of the signal line 109. Furthermore, FIG. 5 shows the source potential Vs and gate potential Vg of the drive transistor 202.

[0027] In each pixel 102, one frame period includes a write period in which the write transistor 203 is conductive and writes a luminance signal to the gate of the drive transistor 202, and a light emission period in which the light emitting element 201 emits light after the write period. In FIG. 5, one frame period is shown to start from time t1. The light emitting element 201 was in the light emitting period in the previous frame period before time t1. Also, as described above, the potential VDD1 of the power supply line 211 that supplies a current to the current path 210 via the switching transistor 204 will be described as being lower than the potential VDD2 of the power supply line 212 that supplies a current to the current path 210 via the switching transistor 205.

[0028] 5, during the light emission period, the switching transistor 204 is conductive (ON state), and the writing transistor 203 and the switching transistor 205 are OFF state. Therefore, during the light emission period, a current for causing the light emitting element 201 to emit light is supplied from the power supply line 211.

[0029] At time t1, the light emission period of the previous frame period ends, and the switching transistor 204 transitions to the off state. The path between the power line 211 and the source of the drive transistor 202 is cut off, no current is supplied to the light emitting element 201, and the light emitting element 201 goes out. At time t1, the writing transistor 203 and the switching transistor 205 remain in the off state.

[0030] After a predetermined time has elapsed from time t1, at time t2, the signal voltage Vsig of the luminance signal is supplied to the signal line 109. In Fig. 5, the voltage of the signal line 109 is constant at the voltage Vsig, but changes appropriately according to the luminance signal.

[0031] Next, at time t3, which is a predetermined time after time t2, the write transistor 203 is turned on. When the write transistor 203 is turned on, the signal voltage Vsig of the signal line 109 is written to the gate of the drive transistor 202.

[0032] Subsequently, at time t4 while the write transistor 203 is conductive, the switching transistor 205 is conductive. As the switching transistor 205 is turned on, a current flows from the power supply line 212 to the drive transistor 202. As a result, a voltage |VDD2-Vsig| is applied as the gate-source voltage Vgs of the drive transistor 202, and a drain current Id flows through the drive transistor 202.

[0033] At time t5 when the writing transistor 203 maintains the conductive state, the switching transistor 205 transitions to the off state. At this time, the charge held in the capacitance element 206 is discharged through a path from the driving transistor 202 to the light emitting element 201. When the potential difference between the drain and source of the driving transistor 202 reaches approximately the threshold value as the potential of the source of the driving transistor 202 decreases, the fluctuation of the potential of the source of the driving transistor 202 converges. This causes the threshold correction to be performed.

[0034] Consider a case where the power supply line 211 to which a potential VDD1 lower than the potential VDD2 is supplied is used in threshold correction. In order to make the light emitting element 201 emit light at a low luminance, it is necessary to set the signal voltage Vsig high, and therefore the gate-source voltage Vgs of the driving transistor 202 becomes the voltage |VDD1-Vsig|. The threshold voltage Vth of the driving transistor 202 may vary depending on the pixel 102. Therefore, it is considered that the voltage |VDD1-Vsig| applied between the gate and source of the driving transistor 202 may be lower than the threshold voltage |Vth| of the driving transistor 202 depending on the pixel 102. Due to the variation in the threshold voltage Vth of the driving transistor 202, threshold correction is not performed in the pixel 102 in which the voltage |VDD1-Vsig| is lower than the threshold voltage |Vth|. As a result, the drain current Id varies depending on the pixel 102, and there is a possibility that streaks or unevenness may occur in the image displayed on the light emitting device 101. Therefore, in threshold correction during the signal writing period, power is supplied from the power supply line 212 to which a potential VDD2 higher than the potential VDD1 is supplied. This makes it possible to more reliably perform threshold correction processing in each pixel 102. As the threshold correction processing progresses, the source potential Vs of the driving transistor 202 drops from the potential VDD2, and after a certain period of time, the gate-source voltage Vgs of the driving transistor 202 becomes the threshold voltage |Vth+ΔV|. Here, ΔV is determined by the difference between the source potential Vs and the backgate potential of the driving transistor 202.

[0035] Next, at time t6, the write transistor 203 is turned off, thereby completing the writing of the signal voltage Vsig and the correction process of the threshold voltage.

[0036] At time t7, the switching transistor 204 becomes conductive. As a result, a potential VDD1 is supplied to the source of the driving transistor 202 from the power supply line 211. The driving transistor 202 supplies a drain current Id corresponding to the gate-source voltage Vgs to the light-emitting element 201. As a result, the light-emitting element 201 emits light with an amount of light corresponding to the signal voltage Vsig of the luminance signal written during the signal write period from time t3, and enters the light-emitting period again.

[0037] 5, if the capacitance value of the capacitance element 206 differs for each pixel 102, a difference occurs in the time until the gate-source voltage Vgs of the driving transistor 202 settles to the threshold voltage |Vth+ΔV| during the period in which the threshold correction process is performed. This time difference can be suppressed, for example, by providing a sufficient period from time t5 to time t6 until the gate-source voltage Vgs of the driving transistor 202 approaches the threshold voltage |Vth+ΔV|. Therefore, even if the capacitance value of the capacitance element 206 varies, degradation of image quality can be suppressed.

[0038] 5, in the light emission period, the switching transistor 204 is turned on to supply a current from the power supply line 211. However, this is not limited to this, and as described above, the power supply line 211 and the power supply line 212 may be used depending on the capacitance value of the capacitance element 206.

[0039] Fig. 6 shows an example of the layout of one pixel 102 assuming the operation described with reference to Fig. 5. Fig. 6 shows the patterns of the power supply line 211, the power supply line 212, the signal line 109, and the electrode 601 functioning as the anode of the light emitting element 201. In the pixel 102, the power supply line 211 and the power supply line 212 are arranged in the same wiring layer. In the pixel 102, the power supply line 212 extends along the Y direction in which the power supply line 211 extends.

[0040] In the operation shown in FIG. 5, a current always flows through the power supply line 211 during the light emission period when the switching transistor 204 is conductive. On the other hand, a current flows through the power supply line 212 during a short period from time t4 to time t5 when the switching transistor 205 is conductive. The timing at which the switching transistor 205 is conductive can be shifted for each row, and the amount of current flowing through the power supply line 212 becomes relatively small. On the other hand, during the light emission period, a current corresponding to the light emission luminance of each pixel 102 flows through the power supply line 211. Therefore, a voltage drop of the potential VDD1 of the power supply line 211 may occur over the entire surface of the pixel array section 103. The potential VDD1 of the power supply line 211 is supplied, for example, from the outer periphery of the pixel array section 103 through the power supply line 211, and a current flows for each pixel 102. Therefore, a shading-like luminance distribution occurs in which the luminance level of the light emitting element 201 for the same luminance signal changes depending on the position in the pixel array section 103. For example, in the center of the pixel array section 103, a voltage drop may cause the current flowing through the light emitting element 201 to become less than the desired current amount.

[0041] Therefore, as shown in FIG. 6, the pixel 102 is laid out so that the maximum wiring width d1 of the power line 211 is wider than the maximum wiring width d2 of the power line 212. This can reduce the wiring resistance of the power line 211, and can suppress brightness shading in the Y direction caused by a voltage drop during a light emission period. Here, the wiring widths d1 and d2 can be the widths of the power lines 211 and 212 in the X direction intersecting with the Y direction in which the power lines 211 and 212 extend. The X direction and the Y direction may be orthogonal. In the configuration shown in FIG. 6, the power lines 211 and 212 are arranged in the same wiring layer, but they may be arranged in different wiring layers.

[0042] FIG. 7 shows an example of a layout of one pixel 102 different from that shown in FIG. 6. FIG. 7 shows the patterns of the power supply line 211, the power supply line 212, the signal line 109, and the electrode 601 functioning as the anode of the light emitting element 201. In the pixel 102, the power supply line 211 and the power supply line 212 are arranged in different wiring layers. In the pixel 102, the power supply line 211 and the power supply line 212 extend in intersecting directions. In the configuration shown in FIG. 7, the power supply line 211 extends along the Y direction, and the power supply line 212 extends along the X direction intersecting the Y direction. The X direction and the Y direction may be perpendicular to each other.

[0043] By disposing the power line 211 and the power line 212 on different wiring layers, there is more room in the layout of the wiring layer on which the power line 211 is disposed, and the wiring width of the power line 211 can be increased. By increasing the wiring width of the power line 211, the wiring resistance of the power line 211 is reduced, making it possible to suppress brightness shading in the Y direction caused by a voltage drop during the light emission period. In addition, compared to the configuration shown in FIG. 6, the opposing length of the power line 211 and the power line 212 can be reduced. Therefore, the yield in the manufacturing process can be improved. In addition, the configuration shown in FIG. 8 makes it possible to increase the wiring width of the power line 212 disposed on a wiring layer different from that of the power line 211. Therefore, even when the power line 211 and the power line 212 are used separately during the light emission period, the wiring resistance of the power line 212 is reduced, making it possible to suppress brightness shading in the X direction caused by a voltage drop of the power line 212 during the light emission period.

[0044] Fig. 8 is a block diagram showing a modified example of the light emitting device 101 shown in Fig. 1. In the configuration shown in Fig. 8, in addition to the configuration in Fig. 1, scanning lines 112 are arranged in the row direction (horizontal direction in Fig. 8) from the vertical scanning circuit 104 to the pixel array section 103 so as to correspond to each pixel row of the pixels 102 arranged in the pixel array section 103. The scanning lines 112 are connected to the output terminals of the corresponding rows in the vertical scanning circuit 104, and supply reset signals to the pixels 102.

[0045] Fig. 9 is a diagram showing an example of the circuit configuration of a pixel 102 arranged in the light emitting device 101 shown in Fig. 8. In contrast to the pixel shown in Fig. 2, a reset transistor 207 is arranged in the pixel 102 shown in Fig. 9. The rest of the configuration may be the same as the configuration described above, and the operation may be the same as the configuration described above. Therefore, the following description will focus on the points that are different from the configuration and operation described above, and descriptions of configurations and operations that may be the same will be omitted as appropriate.

[0046] 9, in a current path 210 including a light emitting element 201 and a driving transistor 202, an anode of the light emitting element 201 and a drain of the driving transistor 202 are connected. A reset transistor 207 resets a node N, to which the anode of the light emitting element 201 and the drain of the driving transistor 202 are connected, to a predetermined potential. As shown in FIG 9, a drain of the reset transistor 207 is connected to a power supply line 214 of a potential VRES. Therefore, the predetermined potential at which the node N is reset is the potential VRES of the power supply line 214.

[0047] The potential VRES is a potential at which the luminance of the light-emitting element 201 becomes a black level. The potential VRES may be a potential different from the potential VSS of the power supply line 214, or may be the same as the potential VSS. The gate of the reset transistor 207 is connected to the scanning line 112. In the signal writing period, a reset signal (when the reset transistor 207 is a P-type transistor, the above-mentioned signal level "L") is supplied via the scanning line 112 to make the reset transistor 207 conductive, and the anode of the light-emitting element 201 is connected to the potential VRES. As a result, the charge held in the capacitance element 206 when the switching transistor 205 is made conductive in the period for correcting the threshold value shown in FIG. 5 described above is discharged through a path from the drive transistor 202 to the reset transistor 207, and no current flows through the light-emitting element 201. That is, in the signal writing period, the light-emitting element 201 maintains a non-emitting or black level state. Therefore, the luminance during black display can be reduced, and a light-emitting device 101 with higher contrast can be realized.

[0048] FIG. 10 is a diagram showing a modified example of the pixel 102 shown in FIG. 9. The pixel 102 shown in FIG. 10 further includes a capacitance element 208, which is disposed between a node N2 connecting the source of the driving transistor 202 and the capacitance element 206, and a power line 212, in addition to the capacitance element 206. By disposing the capacitance element 208, the capacitance value of the source of the driving transistor 202 increases during the threshold correction process shown in FIG. 5. Therefore, for example, it is possible to suppress the noise component flowing through the power line 211 from fluctuating the source potential Vs of the driving transistor 202 due to capacitive coupling. The luminance unevenness caused by the fluctuation of the source potential Vs of the driving transistor 202 is suppressed, and the light emitting device 101 can realize a higher quality display. The capacitance element 208 may be disposed in the pixel 102 shown in FIG. 2.

[0049] Here, application examples in which the light emitting device 101 of this embodiment is applied to an image forming device, a display device, a photoelectric conversion device, an electronic device, a lighting device, a mobile object, and a wearable device will be described with reference to Figs. 11(a) and 11(b) to Figs. 19(a) and 19(b). As described above, the light emitting device 101 will be described assuming that an organic light emitting element such as an organic EL element is arranged as the light emitting element 201 in the pixel 102 arranged in the pixel array section 103. First, the details of each component arranged in the pixel array section 103 of the light emitting device 101 will be shown, and then the application examples will be described.

[0050] Structure of organic light-emitting device The organic light-emitting element is provided by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode on a substrate. A protective layer, a color filter, a microlens, etc. may be provided on the cathode. When a color filter is provided, a planarizing layer may be provided between the protective layer and the color filter. The planarizing layer may be made of acrylic resin or the like. The same applies when a planarizing layer is provided between the color filter and the microlens.

[0051] substrate Examples of the substrate include quartz, glass, silicon wafer, resin, and metal. In addition, the substrate may have a switching element such as a transistor, a wiring pattern, and the like, and an insulating layer thereon. The insulating layer may be made of any material as long as it can form a contact hole so that a wiring pattern can be formed between the first electrode and the substrate, and insulation from wiring patterns that are not connected can be ensured. For example, the insulating layer may be made of a resin such as polyimide, silicon oxide, silicon nitride, and the like.

[0052] electrode A pair of electrodes can be used as the electrodes. The pair of electrodes may be an anode and a cathode. When an electric field is applied in the direction in which the organic light-emitting element emits light, the electrode with a higher potential is the anode, and the other is the cathode. It can also be said that the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode.

[0053] A material having a large work function may be selected as the material for the anode. For example, a metal such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, or tungsten, a mixture containing these metals, or an alloy of these metals, or a metal oxide such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), or indium zinc oxide may be used. Also, a conductive polymer such as polyaniline, polypyrrole, or polythiophene may be used as the material for the anode.

[0054] These electrode materials may be used alone or in combination of two or more. The anode may be composed of one layer or multiple layers.

[0055] When the electrode is used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or an alloy thereof, or a laminate of these may be used. The above materials may function as a reflective film without serving as an electrode. When a transparent electrode is used as the electrode, a transparent conductive layer of oxide such as indium tin oxide (ITO) or indium zinc oxide may be used, but is not limited to these. Photolithography technology may be used to form the electrode.

[0056] On the other hand, a material with a small work function may be selected as the material for the cathode. For example, an alkali metal such as lithium, an alkaline earth metal such as calcium, an aluminum, titanium, manganese, silver, lead, chromium, or a mixture containing these metals may be used. Alternatively, an alloy combining these metals may be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, zinc-silver, or the like may be used. Metal oxides such as indium tin oxide (ITO) may also be used. One of these electrode materials may be used alone, or two or more may be used in combination. The cathode may have a single layer structure or a multilayer structure. Silver may be used as the cathode, and a silver alloy may be used to reduce the aggregation of silver. As long as the aggregation of silver can be reduced, the ratio of the alloy is not important. For example, silver:other metal may be 1:1, 3:1, or the like.

[0057] The cathode may be a top-emission element using an oxide conductive layer such as ITO, or a bottom-emission element using a reflective electrode such as aluminum (Al), and is not particularly limited. The method for forming the cathode is not particularly limited, but when a direct current or alternating current sputtering method or the like is used, the coverage of the formed film is good and the resistance of the cathode can be reduced.

[0058] Pixel Isolation Layer The pixel separation layer may be formed of so-called silicon oxide such as silicon nitride (SiN), silicon oxynitride (SiON), or silicon oxide (SiO) formed by chemical vapor deposition (CVD). In order to increase the resistance in the in-plane direction of the organic compound layer, the thickness of the organic compound layer, particularly the hole transport layer, may be thinned on the sidewall of the pixel separation layer. Specifically, the thickness of the organic compound layer on the sidewall can be thinned by increasing the taper angle of the sidewall of the pixel separation layer or the thickness of the pixel separation layer to increase vignetting during deposition.

[0059] On the other hand, the sidewall taper angle and film thickness of the pixel separation layer can be adjusted to such an extent that no voids are formed in the protective layer formed thereon. By preventing voids from being formed in the protective layer, the occurrence of defects in the protective layer can be reduced. Since the occurrence of defects in the protective layer is reduced, deterioration in reliability such as the occurrence of dark spots and poor conduction of the second electrode can be reduced.

[0060] According to this embodiment, even if the taper angle of the sidewall of the pixel separation layer is not steep, it is possible to effectively suppress charge leakage to adjacent pixels. As a result of this study, it was found that the charge leakage can be sufficiently reduced if the taper angle is in the range of 60 degrees or more and 90 degrees or less. The thickness of the pixel separation layer may be 10 nm or more to 150 nm or less. The same effect can be obtained even if the pixel electrode is composed only of a pixel electrode without a pixel separation layer. However, in this case, the thickness of the pixel electrode is half or less than that of the organic layer, or the pixel electrode end is forward tapered to less than 60 degrees, thereby reducing short circuits in the organic light-emitting element.

[0061] In addition, even when the first electrode is a cathode and the second electrode is an anode, a wide color gamut and low-voltage operation are possible by forming an electron transport material and a charge transport layer, and also by forming an emitting layer on the charge transport layer.

[0062] organic compound layer The organic compound layer may be formed as a single layer or as multiple layers. When the organic compound layer has multiple layers, it may be called a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, or the like, depending on its function. The organic compound layer is mainly composed of an organic compound, but may contain inorganic atoms or inorganic compounds. The organic compound layer may contain, for example, copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, or the like. The organic compound layer may be disposed between the first electrode and the second electrode, or may be disposed in contact with the first electrode and the second electrode.

[0063] protective layer A protective layer may be provided on the cathode. For example, by bonding glass provided with a moisture absorbent on the cathode, the intrusion of moisture and the like into the organic compound layer can be reduced, and the occurrence of display defects can be reduced. In another embodiment, a passivation layer such as silicon nitride may be provided on the cathode to reduce the intrusion of moisture and the like into the organic compound layer. For example, after forming the cathode, the cathode may be transported to another chamber without breaking the vacuum, and silicon nitride having a thickness of 2 μm may be formed by a CVD method to form a protective layer. After forming the protective layer using the CVD method, a protective layer may be provided using an atomic layer deposition (ALD) method. The material of the protective layer formed by the ALD method is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed by a CVD method on the protective layer formed by the ALD method. The protective layer formed by the ALD method may have a smaller film thickness than the protective layer formed by the CVD method. Specifically, the film thickness of the protective layer formed by the ALD method may be 50% or less, or even 10% or less, of the film thickness of the protective layer formed by the CVD method.

[0064] Color Filters A color filter may be provided on the protective layer. For example, a color filter taking into consideration the size of the organic light-emitting element may be provided on another substrate, and the substrate on which the color filter is formed and the substrate on which the organic light-emitting element is provided may be bonded together. In addition, for example, a color filter may be patterned on the above-mentioned protective layer using a photolithography technique. The color filter may be made of a polymer.

[0065] planarization layer A planarization layer may be disposed between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing unevenness of the layers below the planarization layer. It may also be called a material resin layer without limiting the purpose. The planarization layer may be composed of an organic compound, and may be a low molecular weight or a high molecular weight compound. In consideration of reducing unevenness, a high molecular weight organic compound may be used for the planarization layer.

[0066] The planarization layer may be provided above and below the color filter. In this case, the constituent materials of each planarization layer may be the same or different. Specifically, the material of the planarization layer may be polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, urea resin, etc.

[0067] Micro Lenses The organic light-emitting device may have an optical member such as a microlens on the light-emitting side. The microlens may be made of acrylic resin, epoxy resin, or the like. The microlens may be intended to increase the amount of light extracted from the organic light-emitting device and control the direction of the extracted light. The microlens may have a hemispherical shape. When the microlens has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the tangent and the hemisphere are the vertices of the microlens. The vertex of the microlens can be determined in the same manner in any cross-sectional view. That is, among the tangents to the semicircle of the microlens in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the tangent and the semicircle are the vertices of the microlens.

[0068] It is also possible to define the midpoint of the microlens. In the cross section of the microlens, a line segment is imaginary from a point where an arc shape ends to a point where another arc shape ends, and the midpoint of the line segment can be called the midpoint of the microlens. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0069] The microlens has a first surface having a convex portion and a second surface opposite to the first surface. The second surface can be disposed closer to the functional layer (light-emitting layer) than the first surface. To adopt such a configuration, it is necessary to form the microlens on the light-emitting device. When the functional layer is an organic layer, a process that becomes high temperature may be avoided in the manufacturing process of the microlens. In addition, when adopting a configuration in which the second surface is disposed closer to the functional layer than the first surface, the glass transition temperatures of all the organic compounds that constitute the organic layer may be 100°C or higher, and it is suitable that the glass transition temperatures are, for example, 130°C or higher.

[0070] Opposing substrate A counter substrate may be disposed on the planarization layer. The counter substrate is called a counter substrate because it is disposed at a position corresponding to the aforementioned substrate. The constituent material of the counter substrate may be the same as that of the aforementioned substrate. When the aforementioned substrate is the first substrate, the counter substrate may be the second substrate.

[0071] organic layer The organic compound layers (hole injection layer, hole transport layer, electron blocking layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) constituting the organic light emitting element according to an embodiment of the present disclosure may be formed by the method described below.

[0072] The organic compound layer constituting the organic light-emitting element according to the embodiment of the present disclosure can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively to the dry process, a wet process can be used in which a layer is formed by dissolving the compound in an appropriate solvent and applying a known coating method (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.).

[0073] Here, when a layer is formed by a vacuum deposition method or a solution coating method, crystallization is unlikely to occur, and the layer has excellent stability over time. When a layer is formed by a coating method, the layer can be formed by combining with an appropriate binder resin.

[0074] Examples of the binder resin include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0075] These binder resins may be used alone as homopolymers or copolymers, or in combination of two or more. If necessary, known additives such as plasticizers, antioxidants, and ultraviolet absorbers may be used in combination.

[0076] Pixel circuit The light emitting device may have a pixel circuit connected to the light emitting element. The pixel circuit may be an active matrix type that controls the light emission of the first light emitting element and the second light emitting element independently. The active matrix type circuit may be a voltage programming circuit or a current programming circuit. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light emitting element, a transistor that controls the light emission luminance of the light emitting element, a transistor that controls the light emission timing, a capacitance that holds the gate voltage of the transistor that controls the light emission luminance, and a transistor for connecting to GND without going through the light emitting element.

[0077] The light-emitting device has a display region and a peripheral region disposed around the display region. The display region has a pixel circuit, and the peripheral region has a display control circuit. The mobility of a transistor constituting the pixel circuit may be smaller than the mobility of a transistor constituting the display control circuit.

[0078] The slope of the current-voltage characteristic of the transistor that constitutes the pixel circuit may be smaller than the slope of the current-voltage characteristic of the transistor that constitutes the display control circuit. The slope of the current-voltage characteristic can be measured by the so-called Vg-Ig characteristic.

[0079] The transistors that make up the pixel circuit are transistors that are connected to a light-emitting element, such as the first light-emitting element.

[0080] Pixels An organic light emitting device includes a plurality of pixels, each of which includes sub-pixels that emit different colors, for example, RGB colors.

[0081] A pixel has an area that emits light, also called a pixel aperture. The pixel aperture may be 15 μm or less, or 5 μm or more. More specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc.

[0082] The spacing between the subpixels may be 10 μm or less, and specifically may be 8 μm, 7.4 μm, or 6.4 μm.

[0083] The pixels may have a known arrangement in plan view. For example, they may be a stripe arrangement, a delta arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in plan view may be any known shape. For example, they may be a rectangle, a quadrangle such as a diamond, or a hexagon. Of course, if the shape is not an exact shape but is close to a rectangle, it is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0084] Uses of the organic light-emitting device according to the embodiment of the present disclosure The organic light-emitting device according to the embodiment of the present disclosure can be used as a component of a display device or a lighting device, and can also be used as an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, or a light-emitting device having a white light source and a color filter.

[0085] The display device may be an image information processing device having an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., an information processing unit that processes the input information, and displays the input image on the display unit.

[0086] The display unit of the imaging device or inkjet printer may have a touch panel function. The driving method of the touch panel function may be an infrared type, a capacitance type, a resistive film type, or an electromagnetic induction type, and is not particularly limited. The display device may be used in the display unit of a multifunction printer.

[0087] Next, further explanation will be given with reference to the drawings. FIG. 11(a) is an example of a pixel which is a component of the pixel array unit 103 described above. The pixel has a sub-pixel 810 (pixel 102). The sub-pixels are divided into 810R, 810G, and 810B according to their light emission. The emitted light color may be distinguished by the wavelength emitted from the light-emitting layer, or the light emitted from the sub-pixel may be selectively transmitted or color-converted by a color filter or the like. Each sub-pixel has a reflective electrode 802 as a first electrode on an interlayer insulating layer 801, an insulating layer 803 covering the edge of the reflective electrode 802, an organic compound layer 804 covering the first electrode and the insulating layer, a transparent electrode 805 as a second electrode, a protective layer 806, and a color filter 807.

[0088] A transistor and a capacitor may be disposed below or inside the interlayer insulating layer 801. The transistor and the first electrode may be electrically connected via a contact hole (not shown) or the like.

[0089] The insulating layer 803 may be called a bank or a pixel separation film. The insulating layer 803 covers the edge of the first electrode and is disposed so as to surround the first electrode. The portion of the first electrode where the insulating layer 803 is not disposed contacts the organic compound layer 804 and becomes a light-emitting region.

[0090] The organic compound layer 804 has a hole injection layer 841 , a hole transport layer 842 , a first light emitting layer 843 , a second light emitting layer 844 , and an electron transport layer 845 .

[0091] The second electrode may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0092] The protective layer 806 reduces the penetration of moisture into the organic compound layer. Although the protective layer is illustrated as being a single layer, it may be a multi-layer. Each layer may be an inorganic compound layer and an organic compound layer.

[0093] The color filters 807 are divided into 807R, 807G, and 807B according to their colors. The color filters may be formed on a planarization film (not shown). A resin protective layer (not shown) may be disposed on the color filters. The color filters may be formed on a protective layer 806. The color filters may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0094] The display device 800 (corresponding to the above-mentioned light-emitting device 101) in FIG. 11(b) includes an organic light-emitting element 826 and a TFT 818 as an example of a transistor. A substrate 811 such as glass or silicon is provided with an insulating layer 812 on the substrate. An active element such as a TFT 818 is provided on the insulating layer, and a gate electrode 813, a gate insulating film 814, and a semiconductor layer 815 of the active element are provided. The TFT 818 is also composed of a semiconductor layer 815, a drain electrode 816, and a source electrode 817. An insulating film 819 is provided on the upper part of the TFT 818. An anode 821 constituting the organic light-emitting element 826 and a source electrode 817 are connected via a contact hole 820 provided in the insulating film.

[0095] The method of electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element 826 and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the embodiment shown in Fig. 11(b). In other words, it is sufficient that either the anode or the cathode is electrically connected to either the TFT source electrode or the drain electrode. TFT stands for thin film transistor.

[0096] 11(b) shows the organic compound layer as one layer, the organic compound layer 822 may be a multi-layer structure. A first protective layer 824 and a second protective layer 825 are provided on the cathode 823 to reduce deterioration of the organic light-emitting element.

[0097] In the display device 800 of FIG. 11(b), transistors are used as switching elements, but other switching elements may be used instead.

[0098] Moreover, the transistor used in the display device 800 of Fig. 11(b) is not limited to a transistor using a single crystal silicon wafer, but may be a thin film transistor having an active layer on an insulating surface of a substrate. Examples of the active layer include single crystal silicon, amorphous silicon, non-single crystal silicon such as microcrystalline silicon, and non-single crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin film transistors are also called TFT elements.

[0099] The transistors included in the display device 800 of Fig. 11(b) may be formed in a substrate such as a silicon substrate. Here, "formed in a substrate" means that the substrate itself, such as a silicon substrate, is processed to produce the transistors. In other words, having a transistor in a substrate can be seen as the substrate and the transistor being integrally formed.

[0100] The organic light-emitting element according to this embodiment has its light emission brightness controlled by a TFT, which is an example of a switching element, and by providing the organic light-emitting element on a plurality of surfaces, an image can be displayed based on the respective light emission brightnesses. Here, the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed of low-temperature polysilicon, or an active matrix driver formed on a substrate such as a silicon substrate. On a substrate may also be within the substrate. Whether to provide a transistor within the substrate or to use a TFT is selected according to the size of the display unit, and if the size is, for example, about 0.5 inches, the organic light-emitting element may be provided on a silicon substrate.

[0101] 12(a) to 12(c) are schematic diagrams showing an example of an image forming apparatus using the light emitting device 101 of this embodiment. An image forming apparatus 926 shown in Fig. 12(a) includes a photoconductor 927, an exposure light source 928, a developing section 931, a charging section 930, a transfer unit 932, a transport section 933 (the transport roller in the configuration of Fig. 12(a)), and a fixing unit 935.

[0102] Light 929 is irradiated from an exposure light source 928, and an electrostatic latent image is formed on the surface of the photoconductor 927. The light emitting device 101 can be applied to this exposure light source 928. The developing unit 931 contains toner or the like as a developer, and can function as a developing device that applies the developer to the exposed photoconductor 927. The charging unit 930 charges the photoconductor 927. The transfer unit 932 transfers the developed image to a recording medium 934. The transport unit 933 transports the recording medium 934. The recording medium 934 can be, for example, paper or film. The fixing unit 935 fixes the image formed on the recording medium.

[0103] 12(b) and 12(c) are schematic diagrams showing a state in which a plurality of light-emitting sections 936 are arranged on an elongated substrate in the longitudinal direction of an exposure light source 928. A light-emitting device 101 can be applied to the light-emitting section 936. That is, a plurality of pixels 102 arranged on a pixel array section 103 are arranged along the longitudinal direction of the substrate. A direction 937 is parallel to the axis of the photoconductor 927. This column direction is the same as the axial direction of the photoconductor 927 when it rotates. This direction 937 can also be called the long axis direction of the photoconductor 927.

[0104] FIG. 12(b) shows a form in which the light-emitting units 936 are arranged along the long axis direction of the photoconductor 927. FIG. 12(c) shows a modified example of the arrangement of the light-emitting units 936 shown in FIG. 12(b), in which the light-emitting units 936 are arranged alternately in the column direction in the first and second columns. The light-emitting units 936 are arranged at different positions in the row direction in the first and second columns. In the first column, a plurality of light-emitting units 936 are arranged at intervals, and in the second column, the light-emitting units 936 are arranged at positions corresponding to the gaps between the light-emitting units 936 in the first column. In addition, a plurality of light-emitting units 936 are also arranged at intervals in the row direction. The arrangement of the light-emitting units 936 shown in FIG. 12(c) can be rephrased as, for example, a state in which the light-emitting units 936 are arranged in a lattice pattern, a state in which the light-emitting units 936 are arranged in a staggered pattern, or a checkerboard pattern.

[0105] FIG. 13 is a schematic diagram showing an example of a display device using the light-emitting device 101 of this embodiment. The display device 1000 may have a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 between an upper cover 1001 and a lower cover 1009. Flexible printed circuits FPCs 1002 and 1004 are connected to the touch panel 1003 and the display panel 1005. An active element such as a transistor is arranged on the circuit board 1007. The battery 1008 does not need to be arranged if the display device 1000 is not a portable device, and even if it is a portable device, it does not need to be arranged at this position. The light-emitting device 101 can be applied to the display panel 1005. The pixels 102 arranged in the pixel array section 103 of the light-emitting device 101 functioning as the display panel 1005 are connected to active elements such as transistors arranged on the circuit board 1007 and operate.

[0106] The display device 1000 shown in Fig. 13 may be used as a display unit of a photoelectric conversion device (which may also be called an imaging device) having an optical unit with a plurality of lenses and an imaging element that receives light that has passed through the optical unit and photoelectrically converts it into an electrical signal. The photoelectric conversion device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the photoelectric conversion device, or may be a display unit disposed within a viewfinder. The photoelectric conversion device may be a digital camera or a digital video camera.

[0107] FIG. 14 is a schematic diagram showing an example of a photoelectric conversion device using the light emitting device 101 of this embodiment. The photoelectric conversion device 1100 may have a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The photoelectric conversion device 1100 may also be called an imaging device. The light emitting device 101 of this embodiment can be applied to the viewfinder 1101 and the rear display 1102, which are display units. In this case, the pixel array unit 103 of the light emitting device 101 may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the moving speed of the subject, and the possibility that the subject will be blocked by an obstruction.

[0108] Since the timing suitable for capturing an image is often short, it is better to display information as soon as possible. Therefore, a light emitting device 101 in which pixels 102 including light emitting elements using an organic light emitting material such as an organic EL element are arranged in a pixel array section 103 may be used in a viewfinder 1101 or a rear display 1102. This is because organic light emitting materials have a fast response speed. A light emitting device 101 using an organic light emitting material is more suitable than a liquid crystal display device for these devices that require a high display speed.

[0109] The photoelectric conversion device 1100 has an optical section (not shown). The optical section has a plurality of lenses, and forms an image on a photoelectric conversion element (not shown) housed in a housing 1104 that receives light that has passed through the optical section. The focal points of the plurality of lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically.

[0110] The light emitting device 101 may be applied to a display unit of an electronic device. In that case, the light emitting device 101 may have both a display function and an operation function. Examples of the portable terminal include a mobile phone such as a smartphone, a tablet, and a head mounted display.

[0111] FIG. 15 is a schematic diagram showing an example of an electronic device using the light emitting device 101 of this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit 1202 may be a biometric recognition unit that recognizes a fingerprint and performs unlocking or the like. A portable device having a communication unit can also be called a communication device. The light emitting device 101 of this embodiment can be applied to the display unit 1201.

[0112] 16(a) and 16(b) are schematic diagrams showing an example of a display device using the light emitting device 101 of this embodiment. FIG. 16(a) shows a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The light emitting device 101 of this embodiment can be applied to the display unit 1302. The display device 1300 may have a base 1303 that supports the frame 1301 and the display unit 1302. The base 1303 is not limited to the form shown in FIG. 16(a). For example, the lower side of the frame 1301 may also serve as the base 1303. The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0113] FIG. 16(b) is a schematic diagram showing another example of a display device using the light-emitting device 101 of the present embodiment. The display device 1310 of FIG. 16(b) is configured to be bendable, and is a so-called foldable display device. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The light-emitting device 101 of the present embodiment can be applied to the first display unit 1311 and the second display unit 1312. The first display unit 1311 and the second display unit 1312 may be one display unit without a joint. The first display unit 1311 and the second display unit 1312 can be separated at the bending point. The first display unit 1311 and the second display unit 1312 may display different images, or the first display unit and the second display unit may display one image.

[0114] FIG. 17 is a schematic diagram showing an example of an illumination device using the light emitting device 101 of the present embodiment. The illumination device 1400 may have a housing 1401, a light source 1402, a circuit board 1403, an optical film 1404, and a light diffusion unit 1405. The light emitting device 101 of the present embodiment can be applied to the light source 1402. The optical film 1404 may be a filter that improves the color rendering of the light source. The light diffusion unit 1405 can effectively diffuse the light of the light source, such as for lighting up, and deliver the light to a wide range. If necessary, a cover may be provided on the outermost part. The illumination device 1400 may have both the optical film 1404 and the light diffusion unit 1405, or only one of them.

[0115] The lighting device 1400 is, for example, a device that illuminates a room. The lighting device 1400 may emit white light, neutral white light, or any other color from blue to red. It may have a dimming circuit that adjusts the light intensity. The lighting device 1400 may have a power supply circuit connected to the light emitting device 101 that functions as the light source 1402. The power supply circuit is a circuit that converts AC voltage into DC voltage. Moreover, white has a color temperature of 4200K, and neutral white has a color temperature of 5000K. Moreover, the lighting device 1400 may have a color filter. Moreover, the lighting device 1400 may have a heat dissipation unit. The heat dissipation unit dissipates heat inside the device to the outside of the device, and examples of the heat dissipation unit include metals with high specific heat and liquid silicon.

[0116] FIG. 18 is a schematic diagram of an automobile having a tail lamp, which is an example of a vehicle lamp using the light emitting device 101 of this embodiment. The automobile 1500 may have a tail lamp 1501, and may be configured to turn on the tail lamp 1501 when braking or the like is performed. The light emitting device 101 of this embodiment may be used as a head lamp as a vehicle lamp. An automobile is an example of a moving body, and the moving body may be a ship, a drone, an aircraft, a railroad car, an industrial robot, or the like. The moving body may have a machine body and a lamp provided thereon. The lamp may indicate the current position of the machine body.

[0117] The light emitting device 101 of this embodiment can be applied to a tail lamp 1501. The tail lamp 1501 may have a protective member that protects the light emitting device 101 functioning as the tail lamp 1501. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, and may be made of polycarbonate or the like. The protective member may be made by mixing a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like with polycarbonate.

[0118] The automobile 1500 may have a body 1503 and a window 1502 attached thereto. The window may be a window for checking the front and rear of the automobile, or may be a transparent display such as a head-up display. The light-emitting device 101 of this embodiment may be used in the transparent display. In this case, the constituent materials of the electrodes and the like of the light-emitting device 101 are made of transparent members.

[0119] 19(a) and 19(b), a further application example of the light emitting device 101 of the present embodiment will be described. The light emitting device 101 can be applied to a system that can be worn as a wearable device, such as smart glasses, a head mounted display (HMD), or smart contacts. An image capturing and displaying device used in such an application example has an image capturing device capable of photoelectrically converting visible light, and a light emitting device capable of emitting visible light.

[0120] 19(a) illustrates glasses 1600 (smart glasses) according to one application example. An imaging device 1602 such as a CMOS sensor or a SPAD is provided on the front side of a lens 1601 of the glasses 1600. In addition, a light emitting device 101 of this embodiment is provided on the back side of the lens 1601.

[0121] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the light emitting device 101 according to each embodiment. The control device 1603 also controls the operations of the image capture device 1602 and the light emitting device 101. The lens 1601 is formed with an optical system for focusing light on the image capture device 1602.

[0122] FIG. 19(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, and the control device 1612 is equipped with an imaging device corresponding to the imaging device 1602 and a light emitting device 101. The lens 1611 is formed with an imaging device in the control device 1612 and an optical system for projecting light emitted from the light emitting device 101, and an image is projected onto the lens 1611. The control device 1612 functions as a power source that supplies power to the imaging device and the light emitting device 101, and controls the operation of the imaging device and the light emitting device 101. The control device 1612 may have a line of sight detection unit that detects the line of sight of the wearer. Infrared light may be used to detect the line of sight. The infrared light emission unit emits infrared light toward the eyeball of a user gazing at a display image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By providing a reduction unit that reduces the amount of light from the infrared light emitting unit to the display unit in a plan view, degradation of image quality is reduced.

[0123] The gaze of the user with respect to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used.

[0124] More specifically, a gaze detection process based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector that indicates the direction (rotation angle) of the eyeball is calculated based on the pupil image and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0125] The light emitting device 101 according to the embodiment of the present disclosure may include an imaging device having a light receiving element, and may control a display image based on user line-of-sight information from the imaging device.

[0126] Specifically, the light emitting device 101 determines a first field of view area to which the user gazes and a second field of view area other than the first field of view area, based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the light emitting device 101, or may be received from an external control device. In the display area of ​​the light emitting device 101, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0127] The display area includes a first display area and a second display area different from the first display area, and an area having a high priority is determined from the first display area and the second display area based on line-of-sight information. The first display area and the second display area may be determined by a control device of the light-emitting device 101, or may be determined by an external control device and received. The resolution of the area having a high priority may be controlled to be higher than the resolution of areas other than the area having a high priority. In other words, the resolution of an area having a relatively low priority may be lowered.

[0128] AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of the line of sight and the distance to an object at the end of the line of sight from the image of the eyeball, using an image of the eyeball and the direction in which the eyeball in the image was actually looking as teacher data. The AI ​​program may be included in the light-emitting device 101, the imaging device, or an external device. If included in the external device, it is transmitted to the light-emitting device 101 via communication.

[0129] When display control is performed based on visual recognition detection, the present invention can be applied to smart glasses that further include an imaging device that captures images of the outside world. The smart glasses can display captured outside information in real time.

[0130] The disclosure of this specification includes the following light-emitting device, display device, photoelectric conversion device, electronic device, lighting device, and mobile object.

[0131] (Item 1) A light-emitting device including a pixel including a light-emitting element, a current path including a drive transistor for supplying a current corresponding to a luminance signal to the light-emitting element, and a capacitance element disposed between a gate and a source of the drive transistor, The pixel further includes a first switching transistor arranged between a first power line supplying a current to the light emitting element and the current path, and a second switching transistor arranged between a second power line supplying a current to the light emitting element and the current path, A light emitting device, wherein the first power supply line and the second power supply line have different potentials.

[0132] (Item 2) the pixel further includes a write transistor for writing the luminance signal to the gate; the potential of the first power supply line is lower than the potential of the second power supply line; one frame period includes a write period during which the write transistor is conductive and writes the luminance signal to the gate, and a light emission period during which the light emitting element is caused to emit light after the write period; during the write period, while the write transistor is conductive, the second switching transistor is conductive; 2. The light emitting device according to item 1, wherein the first switching transistor is conductive during the light emitting period.

[0133] (Item 3) 3. The light emitting device according to item 2, wherein in the pixel, the maximum wiring width of the first power supply line is wider than the maximum wiring width of the second power supply line.

[0134] (Item 4) 4. The light emitting device according to item 3, wherein in the pixel, the first power supply line and the second power supply line are arranged in the same wiring layer.

[0135] (Item 5) 5. The light emitting device according to item 4, wherein in the pixel, the second power supply line extends in a direction along which the first power supply line extends.

[0136] (Item 6) 4. The light emitting device according to item 3, wherein in the pixel, the first power supply line and the second power supply line are arranged in different wiring layers.

[0137] (Item 7) 7. The light emitting device according to item 6, wherein in the pixel, the first power supply line and the second power supply line extend in intersecting directions.

[0138] (Item 8) a pixel array unit in which a plurality of pixels including the pixel are arranged in rows and columns, 2. The light-emitting device according to item 1, characterized in that during a light-emitting period in which the light-emitting elements are made to emit light, a current is supplied from the first power line or the second power line to each of the light-emitting elements arranged in the plurality of pixels for each row.

[0139] (Item 9) further comprising a control circuit and a memory; the memory stores capacitance data based on a capacitance value of the capacitive element; The light-emitting device described in item 8, characterized in that during the light-emitting period, the control circuit controls so that current is supplied from the first power line or the second power line to each of the light-emitting elements arranged in the multiple pixels for each row, depending on the capacitance data.

[0140] (Item 10) the potential of the first power supply line is lower than the potential of the second power supply line; a capacitance value of the capacitance element of a pixel arranged in a first row among the plurality of pixels is larger than a capacitance value of the capacitance element of a pixel arranged in a second row different from the first row among the plurality of pixels, The light-emitting device described in item 9, characterized in that during the light-emitting period, the control circuit controls so that current is supplied from the first power supply line to the light-emitting elements of the pixels arranged in the first row among the plurality of pixels, and so that current is supplied from the second power supply line to the light-emitting elements of the pixels arranged in the second row among the plurality of pixels.

[0141] (Item 11) Each of the plurality of pixels further includes a write transistor for writing the luminance signal to the gate; one frame period includes a write period during which the write transistor is conductive and writes the luminance signal to the gate, and the light emission period; 11. The light emitting device according to item 10, wherein, during the writing period, while the writing transistor is conducting, the second switching transistor is conducting.

[0142] (Item 12) the current path is connected between an anode of the light-emitting element and a drain of the driving transistor; 12. The light emitting device according to any one of items 1 to 11, wherein the pixel further includes a reset transistor that resets a node to which the anode and the drain are connected to a predetermined potential.

[0143] (Item 13) The light-emitting device according to any one of items 1 to 12, characterized in that the pixel further includes a capacitive element other than the capacitive element arranged between a node connecting the source and the capacitive element and the second power line.

[0144] (Item 14) 14. A display device comprising: a light-emitting device according to any one of items 1 to 13; and an active element connected to the light-emitting device.

[0145] (Item 15) The imaging device includes an optical unit having a plurality of lenses, an image sensor that receives light that has passed through the optical unit, and a display unit that displays an image, 14. A photoelectric conversion device, wherein the display unit displays an image captured by the imaging element, and the photoelectric conversion device has the light-emitting device according to any one of items 1 to 13.

[0146] (Item 16) A display device having a housing and a communication unit provided in the housing for communicating with an external device, 14. An electronic device, wherein the display unit comprises the light-emitting device according to any one of items 1 to 13.

[0147] (Item 17) A lighting device having a light source and at least one of a light diffusion unit and an optical film, 14. An illumination device, wherein the light source comprises the light emitting device according to any one of items 1 to 13.

[0148] (Item 18) A moving body having a body and a lighting device provided on the body, The lighting device is a moving body having the light emitting device according to any one of items 1 to 13.

[0149] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0150] 101: light emitting device, 102: pixel, 201: light emitting element, 202: driving transistor, 204, 205: switching transistor, 206: capacitance element, 210: current path, 211, 212: power supply lines

Claims

1. A light-emitting device comprising a pixel including a light-emitting element, a current path including a drive transistor for supplying a current corresponding to a luminance signal to the light-emitting element, and a capacitance element disposed between a gate and a source of the drive transistor, the pixel further includes: a first switching transistor arranged between a first power supply line that supplies a current to the light-emitting element and the current path; a second switching transistor arranged between a second power supply line that supplies a current to the light-emitting element and the current path; and a write transistor for writing the luminance signal to the gate; the potential of the first power supply line is lower than the potential of the second power supply line; one frame period includes a write period in which the write transistor is made conductive and the luminance signal is written to the gate, and a light emission period in which the light emitting element is made to emit light after the write period; During the write period, while the write transistor is conducting, the second switching transistor is conducting; The light emitting device, wherein the first switching transistor is conductive during the light emitting period.

2. 2. The light emitting device according to claim 1, wherein in the pixel, the maximum wiring width of the first power supply line is wider than the maximum wiring width of the second power supply line.

3. 3. The light emitting device according to claim 2, wherein in the pixel, the first power supply line and the second power supply line are arranged in the same wiring layer.

4. 4. The light emitting device according to claim 3, wherein the second power supply line extends in the pixel in a direction in which the first power supply line extends.

5. 3. The light emitting device according to claim 2, wherein in the pixel, the first power supply line and the second power supply line are arranged in different wiring layers.

6. 6. The light emitting device according to claim 5, wherein in the pixel, the first power supply line and the second power supply line extend in directions that intersect with each other.

7. a pixel array unit in which a plurality of pixels including the pixel are arranged to form rows and columns, 2. The light emitting device according to claim 1, wherein, during the light emitting period, a current is supplied from the first power supply line or the second power supply line to each of the light emitting elements arranged in the plurality of pixels for each row.

8. further including a control circuit and a memory; the memory stores capacitance data based on a capacitance value of the capacitance element; 8. The light-emitting device according to claim 7, wherein during the light-emitting period, the control circuit controls the supply of current from the first power supply line or the second power supply line to each of the light-emitting elements arranged in the plurality of pixels for each row, in accordance with the capacitance data.

9. A capacitance value of the capacitance element of a pixel arranged in a first row among the plurality of pixels is greater than a capacitance value of the capacitance element of a pixel arranged in a second row different from the first row among the plurality of pixels, 9. The light-emitting device according to claim 8, wherein during the light-emitting period, the control circuit controls so that current is supplied from the first power supply line to the light-emitting elements of pixels arranged in the first row among the plurality of pixels, and current is supplied from the second power supply line to the light-emitting elements of pixels arranged in the second row among the plurality of pixels.

10. the anode of the light-emitting element and the drain of the driving transistor are connected in the current path; 2. The light emitting device according to claim 1, wherein the pixel further includes a reset transistor that resets a node, to which the anode and the drain are connected, to a predetermined potential.

11. 2. The light-emitting device according to claim 1, wherein the pixel further includes a capacitance element other than the capacitance element arranged between the second power line and a node connecting the source and the capacitance element.

12. A display device comprising: a light-emitting device according to claim 1; and an active element connected to the light-emitting device.

13. an optical unit having a plurality of lenses, an image sensor that receives light that has passed through the optical unit, and a display unit that displays an image; A photoelectric conversion device, wherein the display section displays an image captured by the imaging element, and the photoelectric conversion device comprises the light-emitting device according to claim 1 .

14. A display unit is provided in the housing, and a communication unit is provided in the housing and communicates with an external device.

12. An electronic device, wherein the display unit comprises the light-emitting device according to claim 1.

15. A lighting device having a light source and at least one of a light diffusion unit and an optical film, 12. An illumination device, wherein the light source comprises a light emitting device according to claim 1.

16. A moving body having a body and a lighting fixture provided on the body, A moving body, wherein the lighting fixture comprises the light emitting device according to any one of claims 1 to 11.

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