JP2024074234A - Light-emitting device, display device, photoelectric conversion device, electronic device, lighting device, and mobile object - Google Patents

Abstract

[Problem] To increase the capacitance value of a capacitance element for holding a luminance signal. [Solution] A light-emitting device is provided, the light-emitting device having a light-emitting element, a main terminal, and a control terminal for receiving a first signal for controlling the luminance of the light-emitting element, the light-emitting device including a first transistor for supplying a current to the light-emitting element according to a voltage between the main terminal and the control terminal, a first capacitance element formed of a first electrode and a second electrode, and a second capacitance element formed of a third electrode and a fourth electrode, the first electrode being electrically connected to the control terminal of the first transistor, the second electrode and the third electrode being electrically connected to the main terminal of the first transistor, the fourth electrode being electrically connected to a power supply line, the second electrode including a first portion facing the first electrode on a surface on the first electrode side, and the third electrode including a second portion whose shortest distance to the first electrode is shorter than the shortest distance to the first portion of the second electrode. [Selected Figure] Figure 5

Description

The present invention relates to a light-emitting device, a display device, a photoelectric conversion device, an electronic device, a lighting device, and a mobile object.

The light-emitting device described in Patent Document 1 includes a drive transistor for controlling the magnitude of the current supplied to the light-emitting element, and a light-emitting control transistor for controlling whether the light-emitting element emits light or not. A luminance signal is supplied to the gate electrode of the drive transistor. This light-emitting device further includes a capacitive element for holding the luminance signal, and another capacitive element connected to the capacitive element.

JP 2020-76841 A

When a leakage current flows into a capacitive element that holds a luminance signal, the value of the luminance signal changes. The change in the luminance signal caused by the leakage current is smaller as the capacitance value of the capacitive element that holds the luminance signal increases. One aspect of the present invention aims to provide a technology for increasing the capacitance value of the capacitive element that holds the luminance signal.

According to some embodiments, a light-emitting device is provided, the light-emitting device having a light-emitting element, a main terminal, and a control terminal for receiving a first signal that controls the luminance of the light-emitting element, the light-emitting device being provided with a first transistor for supplying a current to the light-emitting element according to a voltage between the main terminal and the control terminal, a first capacitance element formed of a first electrode and a second electrode, and a second capacitance element formed of a third electrode and a fourth electrode, the first electrode being electrically connected to the control terminal of the first transistor, the second electrode and the third electrode being electrically connected to the main terminal of the first transistor, the fourth electrode being electrically connected to a power supply line, the second electrode including a first portion facing the first electrode on a surface on the side of the first electrode, and the third electrode including a second portion whose shortest distance to the first electrode is shorter than the shortest distance to the first portion of the second electrode.

In some embodiments, the capacitance of the capacitive element for holding the luminance signal is increased.

1 is a block diagram illustrating an example of the overall configuration of a light emitting device according to a first embodiment. FIG. 2 is an equivalent circuit diagram illustrating an example of the configuration of a pixel of the light emitting device according to the first embodiment. 2 is a schematic cross-sectional view illustrating an example of the configuration of a pixel of the light-emitting device according to the first embodiment. FIG. FIG. 2 is a schematic plan view illustrating an example of the configuration of a pixel of the light emitting device according to the first embodiment. 3 is a schematic cross-sectional view illustrating an example of an arrangement of electrodes of a pixel of the light-emitting device according to the first embodiment. FIG. FIG. 11 is a schematic cross-sectional view illustrating an example of the configuration of a pixel of a light-emitting device according to a second embodiment. FIG. 13 is a schematic cross-sectional view illustrating an example of the configuration of a pixel of a light-emitting device according to a third embodiment. FIG. 13 is a block diagram illustrating an example of the overall configuration of a light emitting device according to a fourth embodiment. FIG. 13 is an equivalent circuit diagram illustrating an example of the configuration of a pixel of a light emitting device according to a fourth embodiment. FIG. 13 is a schematic cross-sectional view illustrating an example of the configuration of a pixel of a light-emitting device according to a fourth embodiment. FIG. 13 is a diagram showing an example of a display device using the light-emitting device according to the embodiment. FIG. 13 is a diagram showing an example of a display device using the light-emitting device according to the embodiment. 1A to 1C are diagrams illustrating examples of a photoelectric conversion device and an electronic device using the light-emitting device according to the embodiment. FIG. 13 is a diagram showing an example of a display device using the light-emitting device according to the embodiment. 1A and 1B are diagrams illustrating an example of a lighting device and a moving object using the light-emitting device according to the embodiment. FIG. 13 is a diagram showing an example of a wearable device using the light emitting device of the embodiment.

The following embodiments are 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 multiple features, not all of these multiple features are necessarily essential to the invention, and multiple 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 duplicate explanations are omitted.

First Embodiment
An example of the overall configuration of a light-emitting device 101 according to the first embodiment will be described with reference to FIG. 1. The light-emitting device 101 includes a pixel array section 103 and a driving section arranged around the pixel array section 103. The pixel array section 103 includes a plurality of pixels 102 arranged in an array. Each pixel 102 includes a light-emitting element 201 (described later in FIG. 2). The light-emitting element 201 includes an anode and a cathode. The light-emitting element 201 includes an organic layer between the anode and the cathode. The organic layer includes a light-emitting layer. 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 in addition to the light-emitting layer.

The driving unit is a circuit for driving the pixels 102 arranged in the pixel array unit 103. The driving unit includes, for example, a vertical scanning circuit 104 and a signal output circuit 105. In order to supply signals from the driving unit to the pixels 102, the pixel array unit 103 is provided with a plurality of scanning lines 106, a plurality of scanning lines 107, and a plurality of signal lines 108. Each of the plurality of scanning lines 106 extends in the row direction (horizontal direction in FIG. 1). The plurality of scanning lines 106 may correspond one-to-one to the plurality of pixel rows of the pixel array unit 103. Each of the plurality of scanning lines 107 extends in the row direction. The plurality of scanning lines 107 may correspond one-to-one to the plurality of pixel rows of the pixel array unit 103. Each of the plurality of signal lines 108 extends in the column direction (vertical direction in FIG. 1). The plurality of signal lines 108 may correspond one-to-one to the plurality of pixel columns of the pixel array unit 103.

The vertical scanning circuit 104 has an output terminal connected to the scanning line 106 and an output terminal connected to the scanning line 107 for each pixel row. The signal output circuit 105 has an output terminal connected to the signal line 108 for each pixel column.

The vertical scanning circuit 104 supplies a write control signal to the pixel 102 through the scanning line 106 in order to write a luminance signal to each pixel 102 of the pixel array unit 103. The luminance signal is a signal that controls the luminance of the light-emitting element 201. When the light-emitting device 101 is used in a display device, the luminance signal may be called a video signal. The write control signal is a signal that controls the writing of the luminance signal to the pixel 102. The vertical scanning circuit 104 supplies a light-emitting control signal to the pixel 102 through the scanning line 107. The light-emitting control signal is a signal that controls the light emission or non-emission of the pixel 102 (specifically, the light-emitting element 201). The signal output circuit 105 selects either the above-mentioned luminance signal or a reference voltage signal having a reference voltage, and supplies the selected signal to the pixel 102 through the signal line 108.

An example of the circuit configuration of the pixel 102 will be described with reference to FIG. 2. Each of the multiple pixels 102 includes a light-emitting element 201, a driving transistor 202, a writing control transistor 203, a light-emitting control transistor 204, a capacitance element 205, and a capacitance element 206. In the following description, the driving transistor 202 is connected to the anode of the light-emitting element 201, and all the transistors included in the pixel 102 are P-type. However, the configuration of the pixel 102 is not limited to this. For example, the polarity of the light-emitting element 201 and the conductivity type of all the transistors in the pixel 102 may be reversed from the example in FIG. 2. Furthermore, the driving transistor 202 may be P-type and the other transistors may be N-type. The supplied potential and connection are changed according to the conductivity type and polarity of the light-emitting element 201 and the transistors. Furthermore, the number of transistors and capacitance elements included in the pixel 102 is not limited to the example in FIG. 2.

In the following description, each transistor has a control terminal and two main terminals. The control terminal may be a gate, and the two main terminals may be a source and a drain. When a transistor is said to be connected between element A and element B, it means that one of the main terminals of the transistor is electrically connected to element A, and the other main terminal of the transistor is electrically connected to element B. In the description of the circuit diagram in Figure 2, "electrically connect" is simply expressed as "connect."

The light-emitting element 201 emits light at a luminance corresponding to the current supplied thereto. An organic electroluminescent (EL) element may be used for the light-emitting element 201. The current supplied to the light-emitting element 201 charges the capacitance of the anode and cathode of the light-emitting element 201 to a predetermined potential, and a current corresponding to this potential difference flows through the light-emitting element 201. This causes the light-emitting element 201 to emit light at a specified luminance.

The driving transistor 202 supplies a current corresponding to the luminance signal to the light-emitting element 201. Specifically, the control terminal of the driving transistor 202 receives the luminance signal. The driving transistor 202 supplies a current corresponding to the voltage between one main terminal (e.g., a source) and the control terminal to the light-emitting element 201.

The light emission control transistor 204 controls whether the light emitting element 201 emits light or not in accordance with the light emission control signal. Specifically, the control terminal of the light emission control transistor 204 receives the light emission control signal. The light emission control transistor 204 is in either a conductive state or a non-conductive state in accordance with the value of the light emission control signal.

In the configuration shown in FIG. 2, the light-emitting element 201, the drive transistor 202, and the light-emitting control transistor 204 are arranged on a current path that connects the power supply line 207 and the power supply line 208. The power supply line 207 supplies a power supply voltage Vdd. The power supply line 208 supplies a power supply voltage Vss. The power supply voltage Vdd is higher than the power supply voltage Vss.

In the example of FIG. 2, the cathode of the light-emitting element 201 is connected to a power line 208. The anode of the light-emitting element 201 is connected to one main terminal (e.g., drain) of the drive transistor 202. The other main terminal (e.g., source) of the drive transistor 202 is connected to one main terminal (e.g., drain) of the light-emitting control transistor 204. The other main terminal (e.g., source) of the light-emitting control transistor 204 is connected to a power line 207. The control terminal of the light-emitting control transistor 204 is connected to the scanning line 107.

Instead of the configuration of FIG. 2, other elements may be arranged on the path between the power line 208 and the light-emitting element 201, or between the power line 207 and the light-emitting control transistor 204. Also, other elements may be arranged on the path between the light-emitting element 201 and the drive transistor 202, or between the drive transistor 202 and the light-emitting control transistor 204. Also, the light-emitting control transistor 204 may be arranged on the path between the light-emitting element 201 and the drive transistor 202, rather than between the drive transistor 202 and the power line 207.

The write control transistor 203 controls the supply of a luminance signal to the control terminal of the drive transistor 202. Specifically, the control terminal of the write control transistor 203 receives a write control signal. The write control transistor 203 is either conductive or non-conductive according to the value of the write control signal. While the write control transistor 203 is conductive, the luminance signal or the reference voltage signal from the signal line 108 is supplied to the control terminal of the drive transistor 202. While the write control transistor 203 is non-conductive, the signal from the signal line 108 is not supplied to the control terminal of the drive transistor 202.

The write control transistor 203 is connected on a path between the signal line 108 and the control terminal of the drive transistor 202. Specifically, one main terminal of the write control transistor 203 is connected to the control terminal of the drive transistor 202. The other main terminal of the write control transistor 203 is connected to the signal line 108. The control terminal of the write control transistor 203 is connected to the scanning line 106.

The capacitance element 205 is composed of electrodes 205a and 205b. The capacitance element 206 is composed of electrodes 206a and 206b. The electrode 205a is connected to a node 209 on the path between the control terminal of the driving transistor 202 and the main terminal of the write control transistor 203. In the example of FIG. 2, the electrode 205a is connected to the control terminal of the driving transistor 202 and the main terminal of the write control transistor 203. Each of the electrodes 205b and 206a is connected to a node 210 on the path between the main terminal of the driving transistor 202 and the main terminal of the light emission control transistor 204. In the example of FIG. 2, each of the electrodes 205b and 206a is connected to the main terminal of the driving transistor 202 and the main terminal of the light emission control transistor 204. The electrode 206b is connected to a node 211 on the path between the main terminal of the light emission control transistor 204 and the power line 207. In the example of FIG. 2, the electrode 206b is connected to both the main terminal of the light-emitting control transistor 204 and the power line 207.

The driving transistor 202 supplies a current from the power supply line 207 to the light emitting element 201 via the light emitting control transistor 204, thereby causing the light emitting element 201 to emit light. More specifically, the driving transistor 202 supplies a current to the light emitting element 201 according to the voltage between the main terminal and the control terminal on the opposite side to the light emitting element 201 (i.e., the voltage between node 210 and node 209). The voltage at node 209 is held by the capacitive element 205.

The write control transistor 203 becomes conductive in response to a write control signal applied to the control terminal from the vertical scanning circuit 104 via the scanning line 106. As a result, the write control transistor 203 samples the signal voltage or reference voltage of the luminance signal corresponding to the luminance information supplied from the signal output circuit 105 via the signal line 108, and writes it to the pixel 102. This written signal voltage or reference voltage is applied to the control terminal of the drive transistor 202 and is held in the capacitance element 205.

The light emission control transistor 204 becomes conductive in response to a light emission control signal applied to the control terminal from the vertical scanning circuit 104 via the scanning line 107, thereby allowing current to be supplied from the power line 207 to the driving transistor 202. This allows the driving transistor 202 to drive the light emitting element 201, as described above.

The switching operation of the light emission control transistor 204 provides a period during which the light emitting element 201 is in a non-light emitting state (non-light emitting period), and the ratio of the light emitting period during which the light emitting element 201 emits light to the non-light emitting period can be controlled (so-called duty control). This duty control that controls the light emitting element 201 to emit/non-emit light can reduce afterimage blurring that occurs when the light emitting element 201 of each pixel 102 emits light over one frame period, and can improve the image quality, particularly for moving images.

Due to manufacturing errors in the light emitting device 101, the threshold voltage of the drive transistor 202 may differ for each pixel 102. Therefore, even if the same signal voltage is written to each pixel 102, the amount of current flowing through the drive transistor 202 will differ, resulting in variation in the amount of light emitted. Therefore, before writing the signal voltage, an operation may be performed to maintain the threshold voltage of the drive transistor 202 between the gate and source of the drive transistor 202. This operation is called a threshold correction operation. This threshold correction operation reduces the variation in the amount of current of the drive transistor 202 in each pixel 102, achieving uniform light emission.

In the threshold correction operation, a current is passed through the light-emitting element 201 via the light-emitting control transistor 204 and the drive transistor 202, and then the light-emitting control transistor 204 is turned off. This causes a current to flow through the light-emitting element 201 until the voltage between the gate and source of the drive transistor 202 becomes statically stable, i.e., reaches a substantially constant value, and threshold correction is performed.

An example of the cross-sectional structure of the pixel 102 will be described with reference to FIG. 3. The light-emitting device 101 includes a substrate 301, an insulating layer 310, and a light-emitting element 201. The insulating layer 310 is located on the substrate 301. The light-emitting element 201 is located on the insulating layer 310. In other words, the insulating layer 310 is located between the substrate 301 and the light-emitting element 201.

The substrate 301 has a main surface 301a (the upper surface in FIG. 3) on which the drive transistor 202, the write control transistor 203, and the light emission control transistor 204 are formed. The substrate 301 may be formed of, for example, a P-type semiconductor. An N-type well region 303 is formed on the main surface 301a side of the substrate 301 (i.e., the upper side of the substrate 301). The substrate 301 other than the well region 303 becomes a P-type semiconductor region 302.

The substrate 301 has impurity regions 304, 305, and 306 in the well region 303. The impurity regions 304, 305, and 306 are all P-type. Electrodes 308 and 309 are formed on the main surface 301a (upper surface) of the substrate 301. The electrode 308 functions as the gate of the light emission control transistor 204. The impurity regions 305 and 306 function as two main terminals (source and drain) of the light emission control transistor 204. The electrode 309 functions as the gate of the drive transistor 202. The impurity regions 304 and 305 function as two main terminals (source and drain) of the drive transistor 202.

The substrate 301 further has an element isolation portion 307 formed between adjacent pixels 102. As the element isolation portion 307, STI (Shallow Trench Isolation), LOCOS (LOCal Oxidation of Silicon) isolation, N-type diffusion layer isolation, etc. may be used.

The light-emitting element 201 has a cathode 321, an organic light-emitting layer 322, and an anode 323. As described above, the cathode 321 is electrically connected to the power line 208. The anode 323 is electrically connected to the main terminal of the drive transistor 202. The organic light-emitting layer 322 is located between the cathode 321 and the anode 323. A bank portion 324 is disposed at the end of the anode 323. The bank portion 324 prevents the current flowing between the anode 323 and the cathode 321 from leaking to the adjacent pixel 102.

The insulating layer 310 is embedded with a conductive pattern 311, a conductive pattern 312, an electrode 205a, an electrode 205b, an electrode 206a, an electrode 206b, and a plurality of plugs. The insulating layer 310 may be, for example, silicon oxide. Each of the conductive patterns 311 and 312 constitutes a wiring layer. The height of the conductive pattern 311 from the main surface 301a of the substrate 301 is smaller than the height of the conductive pattern 312 from the main surface 301a of the substrate 301. In other words, the conductive pattern 311 is located closer to the main surface 301a of the substrate 301 than the conductive pattern 312. The thickness of the conductive pattern 311 and the thickness of the conductive pattern 312 may be different from each other or may be the same. For example, the conductive pattern 312 may be thicker than the conductive pattern 311. The plurality of plugs embedded in the insulating layer 310 may all have the same thickness or may have different thicknesses.

The heights of the electrodes 205a, 205b, 206a, and 206b from the main surface 301a of the substrate 301 are all greater than the height of the conductive pattern 311 and less than the height of the conductive pattern 312. The electrodes 205a and 205b face each other. A portion of the insulating layer 310 is disposed between the electrodes 205a and 205b. This constitutes the capacitive element 205 with an MIM (Metal-Insulator-Metal) structure. The electrodes 206a and 206b face each other. A portion of the insulating layer 310 is disposed between the electrodes 206a and 206b. This constitutes the capacitive element 206 with an MIM structure.

In the description of electrode 205a, the surface at the top of FIG. 3 is referred to as the top surface of electrode 205a, and the surface at the bottom of FIG. 3 is referred to as the bottom surface of electrode 205a. The top surface and the bottom surface are located on opposite sides of each other. The same applies to electrodes 205b, 206a, and 206b.

The electrode 205a (specifically, its lower surface) is connected to the conductive member in the conductive pattern 311 through the plug 316. The electrode 205b (specifically, its upper surface) is connected to the conductive member 315 in the conductive pattern 312 through the plug 317. The electrode 206a (specifically, its lower surface) is connected to the conductive member 313 in the conductive pattern 311 through the plug 319. The electrode 206b (specifically, its upper surface) is connected to the conductive member in the conductive pattern 312 through the plug 320. The conductive member 315 (specifically, its lower surface) and the conductive member 313 (specifically, its upper surface) are connected to each other by the plug 318. The electrode 205a is electrically connected to the electrode 309 (the gate of the driving transistor 202) and the impurity region 305 through the plug 316, etc. The electrode 205b is electrically connected to the electrode 206a through the conductive members 313 and 315 and the plugs 317, 318, and 319. The electrode 206b is electrically connected to the impurity region 306 through the conductive member 314 and the plug 320. The conductive member 314 is included in the conductive pattern 311. The impurity region 306 corresponds to the node 211 in FIG. 2. Therefore, the impurity region 306 is electrically connected to the power supply line 207.

Each of the electrodes 205a and 205b is located so as to overlap the electrode 309 in a planar view. Each of the electrodes 206a and 206b is located so as to overlap the electrode 308 in a planar view. The driving transistor 202 having the electrode 309 as its gate and the light-emitting control transistor 204 having the electrode 308 as its gate share the impurity region 305. Each of the conductive members 313 and 315 is located so as to overlap the impurity region 305 in a planar view.

With reference to FIG. 4, the arrangement of some of the components of pixel 102 in a plan view relative to main surface 301a of substrate 301 will be described. Hereinafter, the plan view relative to main surface 301a of substrate 301 will simply be referred to as plan view. In FIG. 4, attention is focused on electrodes 205a, 205b, 206a, and 206b and plugs 316 to 320. The cross-sectional view of FIG. 3 is a cross-sectional view taken along line A-A' in FIG. 4. The horizontal direction in FIG. 4 may be the row direction of pixel array section 103, and the vertical direction in FIG. 4 may be the column direction of pixel array section 103. Alternatively, the horizontal direction in FIG. 4 may be the column direction of pixel array section 103, and the vertical direction in FIG. 4 may be the row direction of pixel array section 103.

The arrangement of the electrodes 205a and 205b of the capacitance element 205 will be described below. The arrangement of the electrodes 206a and 206b of the capacitance element 206 may be similar. Each of the electrodes 205a and 205b has a plate shape extending in a direction parallel to the main surface 301a of the substrate 301. The outline of each of the electrodes 205a and 205b is a rectangle in a plan view. Alternatively, the outline of each of the electrodes 205a and 205b may have another shape.

In the example of FIG. 4, electrode 205a is larger than electrode 205b in a planar view. Furthermore, the outline of electrode 205b is contained within the outline of electrode 205a in a planar view. Alternatively, electrode 205b may extend beyond electrode 205a in a planar view. Furthermore, electrode 205a may be smaller than electrode 205b in a planar view.

In a plan view, electrode 205a does not overlap either electrode 206a or 206b. In a plan view, electrode 205b does not overlap either electrode 206a or 206b. Also, as shown in FIG. 3, electrode 205a and electrode 206a are at the same height from main surface 301a of substrate 301. In a plan view, electrode 205a and electrode 206a are at the same height from main surface 301a of substrate 301.

The arrangement of electrodes 205a, 205b, 206a, and 206b will be described in more detail with reference to FIG. 5. FIG. 5(a) is a diagram focusing on the arrangement of these electrodes in the light-emitting device 101 described in FIG. 3 and FIG. 4. FIG. 5(a) shows a cross-sectional view at the same position as FIG. 3. FIG. 5(b) and FIG. 5(c) are diagrams explaining modified examples of the arrangement of FIG. 5(a).

As shown in FIG. 5(a), electrode 205b (specifically, its underside) includes a portion 205c that faces electrode 205a. When a luminance signal is supplied to the control terminal of drive transistor 202, portion 205c of electrode 205b becomes positively charged. Correspondingly, the portion of electrode 205a that faces electrode 205b becomes negatively charged.

The electrode 206a includes a portion 206c whose shortest distance d1 to the electrode 205a is shorter than the shortest distance d2 to the portion 205c of the electrode 205b. The shortest distances d1 and d2 are the distances between two points in a three-dimensional space connected by a straight line. The portion 206c is included in the side of the electrode 206a. The portion 206c faces the side of the electrode 205a. Due to this distance relationship, a parasitic capacitance 500 is generated between the electrodes 205a and 206a. That is, the portion 206c of the electrode 206a is positively charged, and the portion of the electrode 205a facing the electrode 206a is negatively charged. The parasitic capacitance 500 increases the capacitance value of the capacitance element 205. Since the capacitance value between the gate and source of the driving transistor 202 increases, the change in the luminance signal due to the leakage current flowing into the capacitance element 205 is reduced.

In the example shown in Figures 3 and 4, the plug 318 is located between the electrodes 205a and 206a. Such a location of the plug 318 further increases the parasitic capacitance 500 between the electrodes 205a and 206a. Alternatively, the plug 318 may be located in another position.

Next, a modified example of the arrangement of FIG. 5(a) will be described with reference to FIG. 5(b) and FIG. 5(c). In the example of FIG. 5(b), the electrode 205b extends from a position overlapping the electrode 205a in a plan view toward the electrode 206a. Furthermore, the electrodes 206a and 206b are shifted downward in the drawing. Even in such an arrangement, the shortest distance d1 from the portion 206c of the electrode 206a to the electrode 205a is shorter than the shortest distance d2 from the portion 206c of the electrode 206a to the portion 205c of the electrode 205b. Therefore, a parasitic capacitance 510 is generated between the electrodes 205a and 206a. The plug 318 may be located to the side of the electrode 206a, or may penetrate an opening formed in the electrode 206a. Alternatively, the plug 318 may be connected to the upper surface of the electrode 206a.

In the example of FIG. 5(c), the height of electrode 205a from main surface 301a of substrate 301 is greater than the height of electrode 206a from main surface 301a of substrate 301. The height of electrode 205b from main surface 301a of substrate 301 is greater than the height of electrode 206b from main surface 301a of substrate 301. Electrode 206a extends toward capacitance element 205 from a position overlapping electrode 206b in plan view. In plan view, a portion of electrode 206a overlaps electrode 205a.

In the example of FIG. 5(c), electrode 206a also includes portion 206c where the shortest distance d1 to electrode 205a is shorter than the shortest distance d2 to portion 205c of electrode 205b. Specifically, the lower surface of electrode 205a includes a portion facing portion 206c of electrode 206a, and this portion is negatively charged. In the example of FIG. 5(c), a parasitic capacitance 520 is generated between electrode 205a and electrode 206a. Plug 318 may be located to the side of electrode 206a or may pass through an opening formed in electrode 206a. Alternatively, plug 318 may be connected to the upper surface of electrode 206a.

Second Embodiment
A configuration example of a light emitting device 101 according to the second embodiment will be described with reference to Fig. 6. Differences from the first embodiment will be mainly described below. Items not described in the second embodiment may be the same as those in the first embodiment. The modified examples described in Fig. 5(b) and Fig. 5(c) can also be applied to the second embodiment.

Figure 6 shows a cross-sectional view corresponding to Figure 3. In the first embodiment, the conductive member 313 does not overlap the electrode 205a in a plan view. As described above, the conductive member 313 is included in the conductive pattern 311. The conductive member 313 also electrically connects the electrode 205b and the electrode 206a. In the second embodiment, the conductive member 313 extends toward the electrode 205a. In a plan view, the conductive member 313 includes a portion that faces the electrode 205a (specifically, its lower surface). In this arrangement, the parasitic capacitance between the electrode 205a and the conductive member 313 is larger than in the first embodiment. This parasitic capacitance further increases the capacitance value of the capacitance element 205.

Third Embodiment
A configuration example of the light emitting device 101 according to the third embodiment will be described with reference to FIG. 7. The following mainly describes the differences from the second embodiment. The matters not described in the third embodiment may be the same as those in the first and second embodiments. The modified examples described in FIG. 5(b) and FIG. 5(c) can also be applied to the third embodiment. The differences between the second and third embodiments may be applied to the first embodiment.

Figure 7 shows a cross-sectional view corresponding to Figure 6. In the second embodiment, the conductive member 314 does not overlap the electrode 206a in a plan view. As described above, the conductive member 314 is included in the conductive pattern 311. The conductive member 314 also electrically connects the electrode 206b and the power line 208. In the third embodiment, the conductive member 314 extends toward the electrode 206a. In a plan view, the conductive member 314 includes a portion facing the electrode 206a (specifically, its lower surface). In this arrangement, the parasitic capacitance between the electrode 206a and the conductive member 314 is larger than in the second embodiment. That is, the capacitance between the source and drain of the light emission control transistor 204 can be increased. When the threshold is corrected, the light emission control transistor 204 is in a non-conductive state, and the source of the drive transistor 202 is in a floating state. Therefore, the source of the drive transistor 202 is easily affected by voltage fluctuations due to noise, and as a result, the threshold may not be corrected normally. According to the third embodiment, the capacitance between the source and drain of the light-emitting control transistor 204 can be increased, thereby suppressing voltage fluctuations caused by noise.

Fourth Embodiment
A configuration example of a light emitting device 101 according to the fourth embodiment will be described with reference to Fig. 8 to Fig. 10. The following mainly describes the differences from the third embodiment. Items not described in the fourth embodiment may be the same as those in any of the first to third embodiments.

With reference to FIG. 8, an example of the overall configuration of the light-emitting device 101 according to the fourth embodiment will be described. In the fourth embodiment, a plurality of scanning lines 801 are further arranged in the pixel array section 103 of the light-emitting device 101. Each of the plurality of scanning lines 801 extends in the row direction. The plurality of scanning lines 106 may correspond one-to-one to the plurality of pixel rows of the pixel array section 103. The vertical scanning circuit 104 supplies a reset signal to the pixel 102 through the scanning line 801. The reset signal is a signal for resetting the light-emitting element 201 of the pixel 102. The vertical scanning circuit 104 further has an output terminal connected to the scanning line 801 for each pixel row.

An example of the circuit configuration of the pixel 102 of the fourth embodiment will be described with reference to FIG. 2. The pixel 102 further includes a reset transistor 901 and a power line 903. The reset transistor 901 is a transistor for resetting the light-emitting element 201. The reset transistor 901 may be, for example, a P-type.

The control terminal (e.g., gate) of the reset transistor 901 receives a reset signal. One terminal (e.g., source) of the reset transistor 901 is connected to a node 902 on the path between the light-emitting element 201 and the drive transistor 202. In the example of FIG. 9, one terminal of the reset transistor 901 is connected to the anode of the light-emitting element 201 and the main terminal of the drive transistor 202. The other terminal (e.g., drain) of the reset transistor 901 is connected to a power line 903. The power line 903 supplies a power supply voltage Vres. The power supply voltage Vres is a voltage at which the luminance of the light-emitting element 201 becomes a black level. The power supply voltage Vres may be the same value as the power supply voltage Vss, or may be a different value.

During the non-light emitting period, the reset transistor 901 is turned on to connect the anode of the light emitting element 201 to the power line 903, and the two electrodes of the light emitting element 201 are shorted. This allows the light emitting element 201 to be in a non-light emitting state (reset operation). By providing the reset transistor 901 in the pixel 102, the light emitting element 201 can be reliably made to display black during the non-light emitting period, and a light emitting device 101 with a high contrast ratio is realized.

With reference to FIG. 10, an example of the cross-sectional structure of the pixel 102 of the fourth embodiment will be described. The substrate 301 further has an impurity region 1001 in the well region 303. The impurity region 1001 is of P-type. An electrode 1002 is further formed on the main surface 301a of the substrate 301. The electrode 1002 functions as the gate of the reset transistor 901. The impurity regions 304 and 1001 function as two main terminals (source and drain) of the reset transistor 901.

A conductive pattern 1003 is further embedded in the insulating layer 310. The conductive pattern 1003 constitutes a wiring layer. The height of the conductive pattern 1003 from the main surface 301a of the substrate 301 is smaller than the height of the conductive pattern 311 from the main surface 301a of the substrate 301. By further providing the conductive pattern 1003, it becomes easier to implement multiple transistors and gate wiring for driving them within a specified pixel size.

[Configuration of organic light-emitting element]
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. The planarizing layer may be made of acrylic resin, etc. The same applies when a planarizing layer is provided between the color filter and the microlens.

[substrate]
Examples of the substrate include quartz, glass, silicon wafer, resin, and metal. In addition, a switching element such as a transistor and wiring may be provided on the substrate, and an insulating layer may be provided thereon. As the insulating layer, any material can be used as long as it is possible to form a contact hole so that wiring can be formed between the first electrode and the insulating layer, and insulation from wiring that is not connected can be ensured. For example, resin such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[electrode]
A pair of electrodes can be used. 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.

The material that constitutes the anode should preferably have a work function as large as possible. For example, metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, tungsten, etc., mixtures containing these metals, alloys combining these metals, metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide can be used. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

One of these electrode materials may be used alone, or two or more may be used in combination. The anode may be composed of a single layer or multiple layers.

When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates of these can be used. The above materials can also function as a reflective film without acting as an electrode. When used as a transparent electrode, transparent conductive oxide layers such as indium tin oxide (ITO) and indium zinc oxide can be used, but are not limited to these. Photolithography technology can be used to form the electrode.

On the other hand, the material for the cathode should have a small work function. Examples of such materials include alkali metals such as lithium, alkaline earth metals such as calcium, aluminum, titanium, manganese, silver, lead, and chromium, or mixtures containing these metals. Alternatively, alloys combining these metals can be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver can be used. Metal oxides such as indium tin oxide (ITO) can also be used. These electrode materials may be used alone or in combination of two or more types. The cathode may have a single layer or a multilayer structure. Among these, it is preferable to use silver, and it is even more preferable to use a silver alloy 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, the ratio of silver to other metal may be 1:1, 3:1, etc.

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 DC and AC sputtering methods are more preferable because they provide good film coverage and make it easier to reduce resistance.

[Pixel isolation layer]
The pixel separation layer is formed of a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, or a silicon oxide (SiO) film formed by chemical vapor deposition (CVD). In order to increase the resistance in the in-plane direction of the organic compound layer, it is preferable that the thickness of the organic compound layer, particularly the hole transport layer, is thinly formed on the sidewall of the pixel separation layer. Specifically, the thickness of the sidewall can be thinly formed 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.

On the other hand, it is preferable to adjust the sidewall taper angle and film thickness of the pixel separation layer to such an extent that no voids are formed in the protective layer formed on top of the pixel separation layer. Since no voids are 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 continuity of the second electrode can be reduced.

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 a sufficient reduction can be achieved 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 is preferably 10 nm or more and 150 nm or less. The same effect can also be obtained even if the pixel electrode is composed only of a pixel electrode without a pixel separation layer. However, in this case, it is preferable that the thickness of the pixel electrode is half or less than that of the organic layer, or that the end of the pixel electrode has a forward taper of less than 60 degrees, since this reduces short circuits in the organic light-emitting element.

[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, etc., depending on its function. The organic compound layer is mainly composed of an organic compound, but may also contain inorganic atoms and inorganic compounds. For example, it may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, etc. 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.

[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 water or the like into the organic compound layer can be reduced, and the occurrence of display defects can be reduced. In another embodiment, a passivation film such as silicon nitride may be provided on the cathode to reduce the intrusion of water or 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 a silicon nitride film having a thickness of 2 μm may be formed by the CVD method to form a protective layer. A protective layer may be provided using the atomic deposition method (ALD method) after the film formation by the CVD method. The material of the film by the ALD method is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, etc. Silicon nitride may be further formed by the CVD method on the film formed by the ALD method. The film by the ALD method may have a smaller thickness than the film formed by the CVD method. Specifically, it may be 50% or less, or even 10% or less.

[Color filter]
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 then bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer described above using a photolithography technique. The color filter may be made of a polymer.

[Planarization layer]
A planarization layer may be provided between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing unevenness of the layer below. 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, but is preferably a high molecular weight.

The planarization layer may be provided above and below the color filter, and may be made of the same or different materials. Specific examples include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin.

[Microlens]
The organic light-emitting device may have an optical member such as a microlens on its 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. In other words, 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.

It is also possible to define the midpoint of a microlens. In the cross section of the microlens, a line segment can be imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this 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.

The microlens has a first surface having a convex portion and a second surface opposite to the first surface. It is preferable that the second surface is disposed closer to the functional layer than the first surface. To achieve such a configuration, it is necessary to form a microlens on the light-emitting device. When the functional layer is an organic layer, it is preferable to avoid processes that result in high temperatures during the manufacturing process. Furthermore, when the second surface is disposed closer to the functional layer than the first surface, it is preferable that the glass transition temperatures of the organic compounds that make up the organic layer are all 100°C or higher, and more preferably 130°C or higher.

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

[Organic Layer]
The organic compound layers (such as a hole injection layer, a hole transport layer, an electron blocking layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer) constituting the organic light emitting device according to one embodiment of the present invention are formed by the method described below.

The organic compound layer constituting the organic light-emitting device according to one embodiment of the present invention can be formed using a dry process such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively to the dry process, a wet process can be used in which the compound is dissolved in a suitable solvent and a layer is formed using a known coating method (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.).

Here, if 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. In addition, when forming a film by a coating method, a film can be formed by combining with an appropriate binder resin.

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, urea resin, etc.

These binder resins may be used alone as homopolymers or copolymers, or two or more types may be mixed together. If necessary, known additives such as plasticizers, antioxidants, and ultraviolet absorbers may be used in combination.

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

The light-emitting device has a display region and a peripheral region arranged around the display region. The display region has a pixel circuit, and the peripheral region has a display control circuit. The mobility of the transistors constituting the pixel circuit may be smaller than the mobility of the transistors constituting the display control circuit.

The slope of the current-voltage characteristics of the transistors that make up the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistors that make up the display control circuit. The slope of the current-voltage characteristics can be measured by the so-called Vg-Ig characteristics.

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.

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

A pixel emits light in an area also called the pixel aperture. This area is the same as the first area. 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.

The distance between subpixels may be 10 μm or less, specifically 8 μm, 7.4 μm, or 6.4 μm.

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 rectangular, quadrilaterals such as diamonds, or hexagons. Of course, any shape close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[Use of the organic light-emitting device according to one embodiment of the present invention]
The organic light-emitting device according to an embodiment of the present invention 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, a light-emitting device having a white light source and a color filter, etc.

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

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

Next, the display device according to this embodiment will be described with reference to the drawings. In the following embodiments, the display device may be configured with a light-emitting device according to any of the above-described embodiments (e.g., light-emitting device 101).

Figure 11 is a schematic cross-sectional view showing an example of a display device having an organic light-emitting element and a transistor connected to the organic light-emitting element. The transistor is an example of an active element. The transistor may be a thin-film transistor (TFT).

Figure 11 (a) is an example of a pixel, which is a component of the display device according to this embodiment. The pixel has a sub-pixel 1100. The sub-pixels are divided into 1100R, 1100G, and 1100B 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 1102, which is a first electrode, on an interlayer insulating layer 1101, an insulating layer 1103 covering the edge of the reflective electrode 1102, an organic compound layer 1104 covering the first electrode and the insulating layer, a second electrode 1110, a protective layer 1111, and a color filter 1112.

The interlayer insulating layer 1101 may have a transistor and a capacitance element disposed underneath or inside it. The transistor and the first electrode may be electrically connected via a contact hole or the like (not shown).

The insulating layer 1103 is also called a bank or pixel separation film. It covers the ends of the first electrodes and is disposed to surround the first electrodes. The parts where the insulating layer is not disposed are in contact with the organic compound layer 1104 and become the light-emitting areas.

The organic compound layer 1104 has a hole injection layer 1105, a hole transport layer 1106, a first light emitting layer 1107, a second light emitting layer 1108, and an electron transport layer 1109. The second electrode 1110 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode. The protective layer 1111 reduces the penetration of moisture into the organic compound layer. Although the protective layer is illustrated as being a single layer, it may be multiple layers. Each layer may be an inorganic compound layer and an organic compound layer.

The color filters 1112 are divided into 1112R, 1112G, and 1112B according to their colors. The color filters may be formed on a planarization film (not shown). Also, a resin protective layer (not shown) may be provided on the color filters. Also, the color filters may be formed on the protective layer 1111. Or, they may be provided on an opposing substrate such as a glass substrate and then bonded together.

The display device 1150 in FIG. 11(b) includes an organic light-emitting element 1166 and a TFT 1158 as an example of a transistor. A substrate 1151 made of glass, silicon, or the like, and an insulating layer 1152 is provided on the substrate. An active element 1158 such as a TFT is provided on the insulating layer, and a gate electrode 1153, a gate insulating film 1154, and a semiconductor layer 1155 of the active element are provided. The TFT 1158 also includes a semiconductor layer 1155, a drain electrode 1156, and a source electrode 1157. An insulating film 1159 is provided on the top of the TFT 1158. The anode 1161 and source electrode 1157 that constitute the organic light-emitting element 1166 are connected via a contact hole 1160 provided in the insulating film.

The method of electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element 1166 and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the form 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.

In the display device 1150 of FIG. 11(b), the organic compound layer is illustrated as a single layer, but the organic compound layer 1162 may be multiple layers. A first protective layer 1164 and a second protective layer 1165 are provided on the cathode 1163 to reduce deterioration of the organic light-emitting element. In the display device 1150 of FIG. 11(b), a transistor is used as the switching element, but other switching elements may be used instead.

The transistors used in the display device 1150 in FIG. 11(b) are not limited to transistors using single crystal silicon wafers, but may be thin film transistors having an active layer on the insulating surface of a substrate. Examples of active layers 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.

The transistors included in the display device 1150 in FIG. 11(b) may be formed within a substrate such as a Si substrate. Formed within a substrate here means that the substrate itself, such as a Si substrate, is processed to produce the transistors. In other words, having a transistor within a substrate can be seen as the substrate and the transistor being formed integrally.

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 multiple surfaces, an image can be displayed with the respective light emission brightnesses. Note that the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed from low-temperature polysilicon, or an active matrix driver formed on a substrate such as a Si substrate. On the substrate can 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; for example, if the size is about 0.5 inches, it is preferable to provide the organic light-emitting element on a Si substrate.

Figure 12 is a schematic diagram showing an example of a display device according to this embodiment. The display device 1200 may have a touch panel 1203, a display panel 1205, a frame 1206, a circuit board 1207, and a battery 1208 between an upper cover 1201 and a lower cover 1209. Flexible printed circuits FPCs 1202 and 1204 are connected to the touch panel 1203 and the display panel 1205. Transistors are printed on the circuit board 1207. The battery 1208 may not be provided if the display device is not a portable device, and may be provided in a different position even if the display device is a portable device.

The display device according to this embodiment may have a color filter having red, green, and blue colors. The color filters may be arranged such that the red, green, and blue colors are arranged in a delta arrangement.

The display device according to this embodiment may be used in the display section of a mobile terminal. In this case, it may have both a display function and an operation function. Examples of the mobile terminal include mobile phones such as smartphones, tablets, and head-mounted displays.

The display device according to this embodiment may be used in the display section of an imaging device having an optical section with multiple lenses and an imaging element that receives light that has passed through the optical section. The imaging device may have a display section that displays information acquired by the imaging element. The display section may be a display section exposed to the outside of the imaging device, or a display section that is disposed within the viewfinder. The imaging device may be a digital camera or a digital video camera.

FIG. 13(a) is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1300 may have a viewfinder 1301, a rear display 1302, an operation unit 1303, and a housing 1304. The viewfinder 1301 may have a display device according to this embodiment. In this case, the display device may display not only the image to be captured, but also environmental information, imaging instructions, etc. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject moves, the possibility that the subject will be blocked by an obstruction, etc.

The optimal timing for capturing an image is very short, so it is better to display information as soon as possible. Therefore, it is preferable to use a display device using the organic light-emitting element of the present invention. This is because organic light-emitting elements have a fast response speed. A display device using organic light-emitting elements can be used more preferably than liquid crystal display devices, which require high display speed.

The imaging device 1300 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1304. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may be called a photoelectric conversion device. Rather than capturing images sequentially, photoelectric conversion devices can include imaging methods such as a method of detecting the difference from the previous image and a method of cutting out an image that is constantly recorded.

FIG. 13B is a schematic diagram showing an example of an electronic device according to this embodiment. The electronic device 1350 has a display unit 1351, an operation unit 1352, and a housing 1353. The housing 1353 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1352 may be a button or a touch panel type reaction unit. The operation unit may be a biometric recognition unit that recognizes a fingerprint and performs unlocking, etc. An electronic device having a communication unit can also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit. Examples of the electronic device include a smartphone and a notebook computer.

Figure 14 is a schematic diagram showing an example of a display device according to this embodiment. Figure 14 (a) shows a display device such as a television monitor or a PC monitor. The display device 1400 has a frame 1401 and a display unit 1402. The light-emitting device according to this embodiment may be used for the display unit 1402.

It has a frame 1401 and a base 1403 that supports a display unit 1402. The base 1403 is not limited to the form shown in FIG. 14(a). The bottom side of the frame 1401 may also serve as the base.

Furthermore, the frame 1401 and the display unit 1402 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

14B is a schematic diagram showing another example of the display device according to the present embodiment. The display device 1450 in FIG. 14B is configured to be bendable, and is a so-called foldable display device. The display device 1450 has a first display unit 1451, a second display unit 1452, a housing 1453, and a bending point 1454. The first display unit 1451 and the second display unit 1452 may have the light-emitting device according to the present embodiment. The first display unit 1451 and the second display unit 1452 may be a single display unit without a joint. The first display unit 1451 and the second display unit 1452 can be separated by the bending point. The first display unit 1451 and the second display unit 1452 may each display different images, or the first and second display units may display a single image.

Figure 15 (a) is a schematic diagram showing an example of a lighting device according to this embodiment. The lighting device 1500 may have a housing 1501, a light source 1502, a circuit board 1503, an optical film 1504, and a light diffusion section 1505. The light source may have an organic light-emitting element according to this embodiment. The optical filter may be a filter that improves the color rendering of the light source. The light diffusion section can effectively diffuse the light of the light source, such as for lighting up, and deliver the light over a wide range. The optical filter and the light diffusion section may be provided on the light emission side of the lighting. If necessary, a cover may be provided on the outermost part.

The lighting device is, for example, a device that illuminates a room. The lighting device may emit white light, daylight white light, or any other color from blue to red. It may have a dimming circuit that adjusts the light intensity. The lighting device may have an organic light-emitting element of the present invention and a power supply circuit connected thereto. The power supply circuit is a circuit that converts AC voltage into DC voltage. Furthermore, white has a color temperature of 4200K, and daylight white has a color temperature of 5000K. The lighting device may have a color filter.

The lighting device according to this embodiment may also have a heat dissipation section. The heat dissipation section dissipates heat from within the device to the outside, and examples of the heat dissipation section include metals with high specific heat, liquid silicon, etc.

Figure 15(b) is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile has tail lamps, which are an example of a lamp. The automobile 1550 has tail lamps 1551, and may be configured to turn on the tail lamps when braking or the like is performed.

The tail lamp 1551 may have an organic light-emitting element according to this embodiment. The tail lamp may have a protective member that protects the organic EL element. The protective member may be made of any material as long as it has a relatively high strength and is transparent, but it is preferable that the protective member is made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

The automobile 1550 may have a body 1553 and a window 1552 attached thereto. The window may be a transparent display as long as it is not a window for checking the front and rear of the automobile. The transparent display may have an organic light-emitting element according to this embodiment. In this case, the constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may have a body and a lamp provided on the body. The lamp may emit light to indicate the position of the body. The lamp has an organic light-emitting element according to this embodiment.

With reference to FIG. 16, an application example of the display device of each of the above-mentioned embodiments will be described. The display device can be applied to a system that can be attached as a wearable device such as smart glasses, HMD, or smart contacts. An image capturing and display device used in such an application example has an image capturing device capable of photoelectrically converting visible light, and a display device capable of emitting visible light.

Figure 16 (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 display device according to each of the above-mentioned embodiments is provided on the back side of the lens 1601.

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 display device according to each embodiment. The control device 1603 also controls the operation of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light on the image capture device 1602.

Figure 16 (b) illustrates glasses 1650 (smart glasses) according to one application example. The glasses 1650 have a control device 1652, and the control device 1652 is equipped with an imaging device equivalent to the imaging device 1602 and a display device. The lens 1651 is formed with an optical system for projecting light emitted from the imaging device in the control device 1652 and the display device, and an image is projected onto the lens 1651. The control device 1652 functions as a power source that supplies power to the imaging device and the display device, and controls the operation of the imaging device and the display device. The control device 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 to the eyeball of a user who is gazing at a displayed 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 having a reduction means for reducing the light from the infrared light emission unit to the display unit in a planar view, deterioration of image quality is reduced.

The user's line of sight 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 an image of the eyeball. As an example, a gaze detection method based on the Purkinje image formed by reflection of irradiated light on the cornea can be used.

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

A display device according to one embodiment of the present invention may have an imaging device having a light receiving element, and may control the display image of the display device based on user line-of-sight information from the imaging device.

Specifically, the display device determines a first field of view area on which the user gazes and a second field of view area other than the first field of view area based on the 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 display device, or may be received from an external control device. In the display area of the display device, 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 the first field of view area.

The display area has a first display area and a second display area different from the first display area, and an area with a high priority is determined from the first display area and the second display 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 display device, or may be received from an external control device. The resolution of the high priority area may be controlled to be higher than the resolution of areas other than the high priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

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 gaze and the distance to an object in the line of sight from the image of the eyeball, using as training data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI program may be possessed by the display device, the imaging device, or an external device. If possessed by an external device, it is transmitted to the display device via communication.

When display control is based on visual detection, it is preferably applicable to smart glasses that further include an imaging device that captures images of the outside world. The smart glasses can display captured external information in real time.

[Summary of the embodiment]
[Item 1]
A light emitting device, comprising:
A light-emitting element;
a first transistor having a main terminal and a control terminal for receiving a first signal for controlling the luminance of the light-emitting element, the first transistor supplying a current to the light-emitting element according to a voltage between the main terminal and the control terminal;
a first capacitance element formed by a first electrode and a second electrode;
a second capacitance element formed by a third electrode and a fourth electrode,
the first electrode is electrically connected to the control terminal of the first transistor;
each of the second electrode and the third electrode is electrically connected to the main terminal of the first transistor;
the fourth electrode is electrically connected to a power supply line;
the second electrode includes a first portion on a surface on the side of the first electrode that faces the first electrode,
The third electrode includes a second portion whose shortest distance to the first electrode is shorter than the shortest distance to the first portion of the second electrode.
[Item 2]
the light emitting device further includes a substrate having a main surface on which the first transistor is formed,
2. The light emitting device according to claim 1, wherein the first electrode and the third electrode do not overlap each other in a plan view with respect to the main surface.
[Item 3]
3. The light emitting device of claim 2, wherein the first electrode and the third electrode are at the same height from the substrate.
[Item 4]
the first electrode includes a first surface including a portion facing the second electrode, and a second surface on the opposite side to the first surface;
2. The light emitting device of claim 1, wherein the second surface of the first electrode includes a portion facing the second portion of the third electrode.
[Item 5]
The light emitting device comprises:
a second transistor for controlling whether the light emitting element emits light;
5. The light emitting device according to claim 1, further comprising: a third transistor for controlling supply of the first signal to the control terminal of the first transistor.
[Item 6]
the light emitting device further includes a plug for electrically connecting the second electrode and the third electrode;
6. The light emitting device according to any one of claims 1 to 5, wherein the plug is located between the first electrode and the third electrode.
[Item 7]
The light emitting device comprises:
a substrate having a main surface on which the first transistor and the second transistor are formed;
a conductive member for electrically connecting the second electrode and the third electrode,
a height of the conductive member from the substrate is lower than a height of each of the first electrode and the third electrode from the substrate;
7. The light emitting device according to claim 1, wherein the conductive member includes a portion facing the first electrode.
[Item 8]
The light emitting device comprises:
a substrate having a main surface on which the first transistor and the second transistor are formed;
a conductive member for electrically connecting the fourth electrode and the power supply line,
a height of the conductive member from the substrate is lower than a height of each of the first electrode and the third electrode from the substrate;
8. The light emitting device according to any one of claims 1 to 7, wherein the conductive member includes a portion facing the third electrode.
[Item 9]
the light emitting device further includes a substrate having a main surface on which the first transistor and the second transistor are formed,
the first transistor and the second transistor share an impurity region formed in the substrate;
the first electrode is located at a position overlapping an electrode that functions as a gate of the first transistor in a plan view with respect to the main surface,
9. The light-emitting device according to claim 1, wherein the third electrode is positioned so as to overlap an electrode that functions as a gate of the second transistor in a plan view with respect to the principal surface.
[Item 10]
10. The light emitting device according to any one of claims 1 to 9, further comprising a fourth transistor for resetting the light emitting element.
[Item 11]
11. A display device comprising: the light-emitting device according to any one of items 1 to 10; and an active element connected to the light-emitting device.
[Item 12]
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,
11. A photoelectric conversion device, wherein the display unit is a display unit that displays an image captured by the imaging element, and the photoelectric conversion device includes the light-emitting device according to any one of items 1 to 10.
[Item 13]
A display unit is provided in a housing, and a communication unit is provided in the housing and communicates with an external device.
11. An electronic device, wherein the display unit comprises the light-emitting device according to any one of items 1 to 10.
[Item 14]
A lighting device having a light source and at least one of a light diffusion unit and an optical film,
11. An illumination device, wherein the light source comprises the light-emitting device according to any one of items 1 to 10.
[Item 15]
A moving body having a body and a lighting device provided on the body,
11. A moving body, wherein the lighting device has the light-emitting device according to any one of items 1 to 10.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

101 Light emitting device, 201 Light emitting element, 202 Driving transistor, 205 Capacitor, 206 Capacitor

Claims (15)

A light emitting device, comprising:
A light-emitting element;
a first transistor having a main terminal and a control terminal for receiving a first signal for controlling the luminance of the light-emitting element, the first transistor supplying a current to the light-emitting element according to a voltage between the main terminal and the control terminal;
a first capacitance element formed by a first electrode and a second electrode;
a second capacitance element formed by a third electrode and a fourth electrode,
the first electrode is electrically connected to the control terminal of the first transistor;
each of the second electrode and the third electrode is electrically connected to the main terminal of the first transistor;
the fourth electrode is electrically connected to a power supply line;
the second electrode includes a first portion on a surface on the side of the first electrode that faces the first electrode,
The third electrode includes a second portion whose shortest distance to the first electrode is shorter than the shortest distance to the first portion of the second electrode. the light emitting device further includes a substrate having a main surface on which the first transistor is formed,
The light emitting device according to claim 1 , wherein the first electrode and the third electrode do not overlap each other in a plan view with respect to the main surface. The light-emitting device according to claim 2, wherein the first electrode and the third electrode are at the same height from the substrate. the first electrode includes a first surface including a portion facing the second electrode, and a second surface on the opposite side to the first surface;
The light emitting device according to claim 1 , wherein the second surface of the first electrode includes a portion facing the second portion of the third electrode. The light emitting device comprises:
a second transistor for controlling whether the light emitting element emits light;
The light emitting device according to claim 1 , further comprising: a third transistor for controlling the supply of the first signal to the control terminal of the first transistor. the light emitting device further includes a plug for electrically connecting the second electrode and the third electrode;
The light emitting device of claim 1 , wherein the plug is located between the first electrode and the third electrode. The light emitting device comprises:
a substrate having a main surface on which the first transistor is formed;
a conductive member for electrically connecting the second electrode and the third electrode,
a height of the conductive member from the substrate is lower than a height of each of the first electrode and the third electrode from the substrate;
The light emitting device according to claim 1 , wherein the conductive member includes a portion facing the first electrode. The light emitting device comprises:
a substrate having a main surface on which the first transistor is formed;
a conductive member for electrically connecting the fourth electrode and the power supply line,
a height of the conductive member from the substrate is lower than a height of each of the first electrode and the third electrode from the substrate;
The light emitting device according to claim 1 , wherein the conductive member includes a portion facing the third electrode. The light emitting device comprises:
a second transistor for controlling whether the light emitting element emits light;
a substrate having a main surface on which the first transistor and the second transistor are formed,
the first transistor and the second transistor share an impurity region formed in the substrate;
the first electrode is located at a position overlapping an electrode that functions as a gate of the first transistor in a plan view with respect to the main surface,
The light emitting device according to claim 1 , wherein the third electrode is located so as to overlap an electrode that functions as a gate of the second transistor in a plan view relative to the main surface. The light emitting device according to claim 1, further comprising a fourth transistor for resetting the light emitting element. A display device comprising the light-emitting device according to any one of claims 1 to 10 and an active element connected to the light-emitting device. 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,
A photoelectric conversion device, comprising: the display unit that displays an image captured by the imaging element; and the light-emitting device according to claim 1 . A display unit is provided in a housing, and a communication unit is provided in the housing and communicates with an external device.
11. An electronic device, comprising: a display unit comprising the light-emitting device according to claim 1. A lighting device having a light source and at least one of a light diffusion unit and an optical film,
An illumination device, characterized in that the light source comprises a light emitting device according to any one of claims 1 to 10. A moving body having a body and a lighting device provided on the body,
A moving body, comprising: a lighting device comprising: a light emitting device according to claim 1 .