Display device, display, photoelectric conversion device, electronic apparatus, and wearable device

Abstract

To provide a technique advantageous for achieving both prevention of flicker and prevention of blur, in a system dividing one frame period into a plurality of sub-frame periods.SOLUTION: A display device comprises a pixel array, a driving unit that drives the pixel array, and a control unit that controls the driving unit. The control unit controls the driving unit so that each unit frame period is formed of a plurality of sub-frame periods and the duty ratio in each sub-frame period is controlled. The control unit controls the driving unit in each unit frame, so that the duty ratio in the last sub-frame period is smaller than the duty ratio of the first sub-frame period.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a display device, a display apparatus, a photoelectric conversion device, an electronic device, and a wearable device. [Background technology]

[0002] Display devices have come to be used for a variety of purposes in recent years, and development in the field of small displays to be installed in portable devices has been active. Portable devices are easy to use and are used in a variety of environments, both indoors and outdoors. Display devices must be able to provide optimal display images in a variety of ambient brightness environments, from dark environments such as outdoors on a moonless night or indoors with no lights on, to bright environments such as outdoors on a sunny day.

[0003] Display devices refresh the image dozens to hundreds of times per second. The frequency of this refresh is called the refresh rate, an indicator of the display device that outputs the image. While a higher refresh rate is preferable for a more natural-looking image, increasing the refresh rate is undesirable in most cases because it increases the circuit size of the display device and increases power consumption during operation. This is particularly true for small displays used in portable devices, where increased power consumption requires a larger battery, resulting in increased product weight and size. On the other hand, a low refresh rate can result in visible flickering of the image. For this reason, a frequency of around 60 Hz is typically used, at which flicker is difficult to see.

[0004] Display devices such as organic light-emitting diodes (OLEDs) and micro LEDs use self-emitting light-emitting elements for each pixel, which emit light by applying a desired current to each element. The light-emitting period corresponds to the current application period, making it possible to adjust the light-emitting period for one frame. The ratio of the light-emitting period to the frame period is called the duty ratio. When the duty ratio is 100% (when light is constantly emitting), no flicker occurs at 60 Hz. However, with fast-moving images, the large difference between the images of two consecutive frames causes the image to be averaged due to the afterimage effect of human vision, resulting in a blurred image. This afterimage effect is called blur or motion blur. Patent Document 1 describes a technology that reduces flicker by dividing a frame into multiple subframes and emitting light-emitting elements for each subframe for a period corresponding to the duty ratio. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-030516 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a result of the inventor's investigations, it was found that with the technology described in Patent Document 1, the duty ratio does not change between subframes within a frame, and therefore, in fast-moving images, even if duty driving is used, the blur suppression effect may not be sufficient.

[0007] The present invention provides an advantageous technique for suppressing both flicker and blur in a system in which one frame period is divided into a plurality of sub-frame periods. [Means for solving the problem]

[0008] One aspect of the present invention relates to a display device including a pixel array, a driver that drives the pixel array, and a controller that controls the driver, wherein the controller controls the driver so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled, and the controller controls the driver so that, in each unit frame, the duty ratio of the last subframe period is smaller than the duty ratio of the first subframe period. [Effects of the Invention]

[0009] According to the present invention, an advantageous technique for suppressing both flicker and blur is provided. [Brief explanation of the drawings]

[0010] [Figure 1] 4 is a timing chart showing the operation of the display device according to the first embodiment. [Figure 2] FIG. 1 is a diagram schematically illustrating a configuration of a display device according to an example of the first embodiment. [Figure 3] FIG. 2 is a diagram showing the configuration of a control unit of a display device according to an example of the first embodiment. [Figure 4] 1 is a timing chart showing the operation of the display device of Example 1-1. [Figure 5] 1 is a timing chart for explaining Example 1-1. [Figure 6] 1 is a timing chart for explaining Example 1-1. [Figure 7] 10 is a timing chart showing the operation of the display device in Example 1-2. [Figure 8] 10 is a timing chart showing the operation of the display device in accordance with Examples 1-3. [Figure 9] 10 is a timing chart showing the operation of the display device in Examples 1-4. [Figure 10] 10 is a timing chart showing the operation of the display device in Examples 1-5. [Figure 11] 10 is a timing chart showing the operation of the display device in Examples 1-6. [Figure 12] 10 is a timing chart showing the operation of a display device according to a second embodiment. [Figure 13] 10 is a timing chart showing the operation of the display device of Example 2-1. [Figure 14] 10 is a timing chart showing the operation of the display device of Example 2-2. [Figure 15] 10 is a timing chart showing the operation of the display device of Example 3-1. [Figure 16] FIG. 10 is a diagram showing the configuration of a control unit of a display device according to Example 3-2. [Figure 17] 10 is a timing chart showing the operation of the display device of Example 3-2. [Figure 18] FIG. 1 is a diagram illustrating a configuration of a display device according to an embodiment. [Figure 19] FIG. 1 is a diagram illustrating a configuration of a display device according to an embodiment. [Figure 20] 1 is a diagram illustrating an imaging device and an electronic device according to an embodiment; [Figure 21] FIG. 1 is a diagram illustrating a display device according to an embodiment. [Figure 22] FIG. 1 illustrates smart glasses according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted. (First embodiment) A display device according to a first embodiment may include a pixel array, a driver that drives the pixel array, and a controller that controls the driver. The controller may control the driver so that each unit frame period is composed of a plurality of subframe periods and the duty ratio of each subframe period is controlled. The controller may control the driver so that the duty ratio of the first subframe period is different from the duty ratio of the last subframe period in each unit frame. The controller may control the driver so that each subframe period is composed of a light-emitting period and a non-light-emitting period, with the light-emitting period starting at the start of each subframe period and the non-light-emitting period starting at the end of the light-emitting period. The controller may control the driver so that the duty ratio of the last subframe period in each unit frame is smaller than the duty ratio of at least the first subframe period. The controller may control the driver so that the duty ratio of the last subframe period in each unit frame is smaller than the duty ratios of all subframe periods other than the last subframe period. The control unit can control the drive unit so that the non-light emitting period in the last sub-frame period in each frame period is 3 msec or longer.

[0012] FIG. 1 shows one frame period t V The operation of one frame period t V is also called one vertical scanning period or unit frame period. A luminance signal is supplied to each pixel of the pixel array once per frame period, and a signal corresponding to the luminance signal can be written. Since the duty ratio of the last subframe period is smaller than the duty ratio of at least the first subframe period among the multiple subframe periods that make up each frame period, t Ln <t L1 (and t D1 <t Dn ) is satisfied, where t L1 is the light emission period in the first subframe period, and t D1 is the non-emission period in the first subframe period. Ln is the light emission period in the last subframe period, and tDn is the non-light emitting period in the last sub-frame period.

[0013] The display device may be, for example, a self-emissive display device such as an OLED (Organic Light Emitting Diode) or a microLED. Self-emissive display devices have the advantage of having a higher refresh rate than non-self-emissive display devices such as LCDs (Liquid Crystal Displays).

[0014] The display device may constitute a display device together with a power supply unit, an image control unit, an operation control unit, etc. The display device may be configured as, for example, a smartphone, a monitor display, an XR device, an EVF (Electronic View Finder), a monocular, binoculars, night vision goggles, etc., and may be portable or non-portable. Furthermore, the display device may be large or small in size. An optical system such as a lens may be disposed between the display device and the eye.

[0015] The display device of the first embodiment will be exemplarily described below through several examples. (Example 1-1) FIG. 2 schematically illustrates the configuration of a display device according to Example 1-1. The display device 10 may include a pixel array 12, a vertical scanning circuit 13, a signal output circuit 14, and a control unit 20. The vertical scanning circuit 13 and the signal output circuit 14 may form a drive unit 50 that drives the pixel array 12. The pixel array 12 includes a plurality of pixels 11 arranged in a plurality of rows and columns. The control unit 20 may generate a plurality of control signals that control the vertical scanning circuit 13 and the signal output circuit 14. The control unit 20 may, for example, supply the vertical scanning circuit 13 with a scanning control signal 24 for vertical scanning and a light-emitting control signal 21 that controls the duty ratio (emission period in another sense). The control unit 20 may also supply a signal output control signal 22 and display image data 23 to the signal output circuit 14.

[0016] The vertical scanning circuit 13 may be configured to drive multiple scanning line groups 15 extending in the row direction. Each scanning line group 15 may include a write control line and a drive signal line. Each pixel 11 may include a light-emitting element, a drive transistor that drives the light-emitting element in accordance with a luminance signal, a switch transistor that controls whether the light-emitting element emits light, and a write transistor that writes a signal corresponding to the luminance signal to the gate of the drive transistor. The luminance signal may be supplied to the write transistor from the signal output circuit 14 via a signal line 16. The write control line may be connected to the gate of the write transistor, and the drive signal line may be connected to the gate of the switch transistor. A period during which the drive signal supplied to the drive signal line is activated is a light-emitting period, and a period during which the drive signal supplied to the drive signal line is deactivated is a non-light-emitting period. The vertical scanning circuit 13 controls the voltage of the write control line for each row, i.e., the write control signal, in accordance with a vertical scanning control signal 24.

[0017] The signal output circuit 14 performs D / A conversion on the display image data 23 sequentially sent from the control unit 20 to generate a voltage signal having a voltage corresponding to the value of the display image data 23 as a luminance signal, and outputs the voltage signal to each signal line 16. A pixel 11 is disposed at each intersection of the scanning line group 15 and the signal line 16, and the scanning line group 15 and the signal line 16 are connected to the corresponding pixel 11.

[0018] The light-emitting element of the pixel 11 may be, for example, an OLED, and the transistors such as the drive transistor, switch transistor, and write transistor may be, for example, a FET (Field Effect Transistor). The OLED may be configured, for example, by sequentially stacking a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and the like between an anode and a cathode, at least one of which is transparent. The FET may be, for example, a silicon TFT (Thin Film Transistor).

[0019] FIG. 3 shows an example configuration of the control unit 20. FIG. 3 focuses on the generation of the light-emission control signal 21, and the signal output control signal 22, display image data 23, and scanning control signal 24 may be generated according to known techniques. The control unit 20 may include a timing generator (TG) 30 and a receiving unit 40. The receiving unit 40 may receive a brightness setting signal and supply it to the TG 30. The TG 30 may receive image data and a synchronization signal (not shown) supplied from outside the display device 10, and generate the signal output control signal 22, display image data 23, and scanning control signal 24. The TG 30 may include a light-emission control unit 31 that generates the light-emission control signal 21 (light-emission pulse) according to the brightness setting signal supplied from the receiving unit 40. The light-emission control unit 31 may include, for example, a brightness level setting unit 32 and a light-emission pulse generating unit 33.

[0020] A display device including the display device 10 may have an interface (e.g., physical buttons, GUI, etc.) for setting the brightness of the display device 10. When the user operates such an interface to change the brightness, a brightness setting signal may be supplied to the control unit 20 (receiving unit 40) of the display device 10. When the receiving unit 40 receives the brightness setting signal and supplies it to the TG 30, the brightness level setting unit 32 of the TG 30 sets the brightness and duty ratio for each frame period. The light emission pulse generating unit 33 may generate a light emission control signal 21 (pulse signal) that defines a light emission period and a non-light emission period according to the duty ratio set by the brightness level setting unit 32. The TG 30 may generate display image data 23 according to the brightness and image data set by the brightness level setting unit 32.

[0021] The control unit 20 (from another point of view, the TG 30 or the light emission pulse generating unit 33) can generate the light emission control signal 21 so as to divide one frame (unit frame) period of the image data into a plurality of (in other words, n) subframe periods equally in time. The light emission period of the first subframe period, subframe period 1, is defined as t L1 , the non-emission period is t D1 Similarly, the light emission period of the kth subframe period k (k is an integer between 1 and n) is expressed as tLk , the non-emission period is t Dk Since one frame period is divided into multiple subframe periods evenly in time, t L1 +t D1 =t L2 +t D2 ==t Ln +t Dn In the first embodiment, at least t Ln <t L1 (t D1 <t Dn In order to simplify the control by the control unit 20, it is preferable to set t Ln <t L1 ==t Ln-1 However, depending on the relationship between the timing setting of the image data displayed by the display device 10 and the number of divisions of one frame period (total number of sub-frame periods) n, it may be possible to divide the image data completely evenly (t L1 +t D1 =t L2 +t D2 ==t Ln +t Dn It is preferable to divide it evenly, but Ln <t L1 An error may occur within a range that does not deviate from the above relational expression.

[0022] In Example 1-1, the refresh rate of the display device 10 is set to 60 Hz. Also, in Example 1-1, one frame period of image data of 60 fps (frames per second) is divided into two sub-frame periods, as shown in Fig. 4. Each sub-frame period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each sub-frame period and the non-light-emitting period starts at the end of the light-emitting period.

[0023] One frame period is t v Then, in Example 1-1, t L1 =(1 / 2)t v *0.17=0.085tv , t L2 =(1 / 2)t v *0.10=0.050t v Therefore, t Ln <t L1 It is as follows.

[0024] In this way, the light-emission control unit 31 controls the vertical scanning circuit 13 so that the duty ratio of the last subframe period in each frame period is smaller than the duty ratio of at least the first subframe period. Because each frame period is divided into two subframe periods at a refresh rate of 60 Hz, the apparent refresh rate is 120 Hz. Since flicker is barely noticeable when driven at 120 Hz, it can be said that flicker is suppressed in Example 1-1. Furthermore, compared to when all subframe periods are driven with a duty ratio of 17%, the subframe period immediately before the display image data switches (subframe period 2 in Example 1-1) has a duty ratio of 10%, resulting in a longer non-emission period of 90%. The longer non-emission period immediately before the display image data switches can further reduce blurring, which occurs when an image is averaged out due to the persistence of vision in human vision.

[0025] Furthermore, as a result of the inventor's investigation, it was found that when a non-light emitting period is provided after a light emitting period in a sub-frame period, the suppression effect is enhanced if the period during which the display image data is changed between two consecutive frame periods is 3 msec or more. The period during which the display image data is changed between two consecutive frame periods is the period from the end of the light emitting period of the last sub-frame period to the start of light emission of the first sub-frame period of the next frame period. More specifically, the period during which the vertical synchronization signal is disabled between two consecutive frame periods is called t vsoff In this case, t Dn +t vsoff It is preferable that t is ≥ 3 msec. Dn is the duty ratio of the last subframe period, R dn When t Dn =t v / (n*Rdn ) However, in display devices, it is usually vsoff is on the order of 0.01 msec (t vsoff <<3msec), so t Dn It is preferable to control the time so as to satisfy t ≧ 3 msec. D2 =7.5msec.

[0026] In Example 1-1, when the user attempts to change the brightness setting, the receiving unit 40 receives the brightness setting information and sends a signal to the brightness level setting unit 32. When the user attempts to increase the brightness, the brightness level setting unit 32 can set the brightness in accordance with the driving example shown in FIG. 5. The same driving as that shown in FIG. 4 is set as the initial state (a). In contrast, in (b-1), the intensity of the light emission pulse is increased to increase the brightness. In (b-2), the light emission period t Ln (In the case of Example 1-1, t L2 In (b-3), the luminance is increased by lengthening the light emission period of the subframe period other than the last subframe period (in the case of Example 1-1, the light emission period t L1 ) is made longer to increase the brightness.

[0027] In the driving method (duty driving) of controlling the duty ratio, there are cases where the method of increasing the luminance by increasing the intensity of the light emitting pulse as in (b-1) is not preferable. For example, there are cases where the luminous efficiency of the display element does not increase even if the voltage is increased, or there are cases where there is a limit due to the maximum voltage that can be supplied to the light emitting element. In (b-2), in order to achieve the effect of the first embodiment, t L2 <t L1 The above condition must be satisfied, and the brightness may be limited by this condition. Therefore, it is preferable to set it as in the example of (b-3). However, the brightness may be set by combining (b-1), (b-2), and (b-3).

[0028] Similarly, when the user wants to darken the brightness, the brightness level setting unit 32 can set it according to the driving example shown in Fig. 6. In (c-1), the intensity of the light emitting pulse is lowered to lower the brightness. In (c-2), the light emitting period t Ln (In the case of Example 1-1, t L2 In (c-3), the luminance is reduced by shortening the light emission period of the subframe period other than the last subframe period (in the case of Example 1-1, the light emission period t L1 ) is shortened to reduce the brightness. L2 Since t cannot be set to less than 0, there is a lower limit to the brightness setting. L2 <t L1 Since the above condition must be satisfied, the brightness may be limited by this condition. Therefore, it is preferable to set it as in the example of (c-1). However, the brightness may be set by combining (c-1), (c-2), and (c-3). (Example 1-2) In Example 1-2, the refresh rate of the display device 10 is set to 60 Hz. Also, in Example 1-2, one frame period of 60 fps image data is divided into four sub-frame periods, as shown in Fig. 7. Each sub-frame period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each sub-frame period and the non-light-emitting period starts at the end of the light-emitting period.

[0029] At a refresh rate of 60 Hz, each frame period is divided into four subframe periods, so the apparent refresh rate is 240 Hz. Since flicker is barely noticeable when driven at 240 Hz, it can be said that flicker is suppressed in Example 1-2. Furthermore, compared to when all subframe periods are driven with a duty ratio of 25%, the last subframe period in which the display image data switches (subframe period 4 in Example 1-2) has a duty ratio of 15%, so the non-emission period is long at 85%. The long non-emission period immediately before the display image data switches can further suppress blurring, which occurs when the image is averaged out due to the afterimage effect of human vision. Furthermore, t D4 = 3.5 msec, so t Dn ≥ 3 msec.

[0030] In Example 1-2, if the user wishes to change the brightness setting, the setting can be done in the same way as described in Example 1-1. (Examples 1-3) In Examples 1-3, the refresh rate of the display device 10 is set to 60 Hz. In Examples 1-3, one frame period of 60 fps image data is divided into five subframe periods, as shown in Fig. 8. Each subframe period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each subframe period and the non-light-emitting period starts at the end of the light-emitting period.

[0031] At a refresh rate of 60 Hz, each frame period is divided into five subframe periods, so the apparent refresh rate is 300 Hz. Since flicker is barely noticeable when driven at 300 Hz, it can be said that flicker is suppressed in Example 1-3. Furthermore, compared to when all subframe periods are driven with a duty ratio of 50%, the last subframe period in which the display image data switches (subframe period 5 in Example 1-3) has a duty ratio of 10%, so the non-emission period is long at 90%. The long non-emission period immediately before the display image data switches can further suppress blurring, which occurs when the image is averaged out due to the afterimage effect of human vision. Furthermore, t D5 = 3.0 msec, so t Dn ≥ 3 msec.

[0032] In Example 1-3, if the user wishes to change the brightness setting, the setting can be done in the same way as described in Example 1-1. (Examples 1-4) In Example 1-4, the refresh rate of the display device 10 is set to 72 Hz. In Example 1-4, one frame period of 72 fps image data is divided into three sub-frame periods, as shown in Fig. 9. Each sub-frame period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each sub-frame period and the non-light-emitting period starts at the end of the light-emitting period.

[0033] At a refresh rate of 72 Hz, each frame period is divided into three sub-frame periods, so the apparent refresh rate is 216 Hz. Since flicker is barely noticeable when driven at 216 Hz, it can be said that flicker is suppressed in Example 1-4. Furthermore, compared to when all sub-frame periods are driven with a duty ratio of 40%, the last sub-frame period in which the display image data switches (sub-frame period 3 in Example 1-4) has a duty ratio of 30%, so the non-emission period is long at 70%. The long non-emission period immediately before the display image data switches can further suppress blurring, which occurs when the image is averaged out due to the afterimage effect of human vision. Furthermore, t D3 = 3.2 msec, so t Dn ≥ 3 msec.

[0034] In the first to fourth embodiments, when the user wishes to change the brightness setting, the setting can be performed in the same manner as described in the first embodiment. (Examples 1-5) In Examples 1-5, the refresh rate of the display device 10 is set to 90 Hz. In Examples 1-5, one frame period of 90 fps image data is divided into three subframe periods, as shown in Fig. 10. Each subframe period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each subframe period and the non-light-emitting period starts at the end of the light-emitting period.

[0035] At a refresh rate of 90 Hz, each frame period is divided into three subframe periods, so the apparent refresh rate is 270 Hz. Since flicker is barely noticeable when driven at 270 Hz, it can be said that flicker is suppressed in Examples 1-5. Furthermore, compared to when all subframe periods are driven with a duty ratio of 30%, the last subframe period in which the display image data switches (subframe period 3 in the case of Examples 1-5) has a duty ratio of 15%, so the non-emission period is long at 85%. The long non-emission period immediately before the display image data switches can further suppress blurring, which occurs when the image is averaged out due to the afterimage effect of human vision. In addition, t D3 = 3.1 msec, so t Dn ≥ 3 msec.

[0036] In Example 1-5, when the user wishes to change the brightness setting, the setting can be performed in the same manner as described in Example 1-1. (Examples 1 to 6) In Examples 1-6, the refresh rate of the display device 10 is set to 120 Hz. In Examples 1-6, one frame period of 120 fps image data is divided into two sub-frame periods, as shown in Fig. 11. Each sub-frame period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the light-emitting period starts at the start of each sub-frame period and the non-light-emitting period starts at the end of the light-emitting period.

[0037] At a refresh rate of 120 Hz, each frame period is divided into two sub-frame periods, so the apparent refresh rate is 240 Hz. Since flicker is barely noticeable when driven at 240 Hz, it can be said that flicker is suppressed in Example 1-5. Furthermore, compared to when all sub-frame periods are driven with a duty ratio of 33%, the last sub-frame period in which the display image data switches (sub-frame period 2 in Example 1-6) has a duty ratio of 25%, so the non-emission period is long at 75%. The long non-emission period immediately before the display image data switches can further suppress blurring, which occurs when the image is averaged out due to the afterimage effect of human vision. Furthermore, t D2 = 3.1 msec, so t Dn ≥ 3 msec.

[0038] In Example 1-6, if the user wishes to change the brightness setting, the setting can be done in the same manner as described in Example 1-1. (Second embodiment) The second embodiment will be described below, but matters not mentioned in the second embodiment may follow the first embodiment. In the second embodiment, the control unit 20 may control the drive unit 50 so that each subframe period is composed of a light-emitting period and a non-light-emitting period, the non-light-emitting period starts at the start of each subframe period, and the light-emitting period starts at the end of the non-light-emitting period. The control unit 20 may control the drive unit 50 so that the duty ratio of the first subframe period in each unit frame is smaller than the duty ratio of at least the last subframe period. The control unit 20 may control the drive unit 50 so that the duty ratio of the first subframe period in each unit frame is smaller than the duty ratios of subframe periods other than the first subframe period. The control unit 20 may control the drive unit 50 so that the non-light-emitting period of the first subframe period in each frame period is 3 msec or longer.

[0039] FIG. 12 shows a graph of one frame period t VThe operation of t is illustrated. Since the duty ratio of the first subframe period is smaller than the duty ratio of the last subframe period among the multiple subframe periods that make up each frame period, L1 <t Ln (and t Dn <t D1 ) is satisfied. Example 2-1 The control unit 20 (from another point of view, the TG 30 or the light emission pulse generating unit 33) can generate the light emission control signal 21 so as to divide one frame (unit frame) period of the image data into a plurality of (in other words, n) subframe periods equally in time. D1 , the light emission period is t L1 Similarly, the non-emission period of the kth (k is an integer between 1 and n) subframe period k is expressed as t Dk , the light emission period is t Lk Since one frame period is divided into multiple subframe periods evenly in time, t D1 +t L1 =t D2 +t L2 ==t Dn +t Ln In the second embodiment, at least t L1 <t Ln (t Dn <t D1 In order to simplify the control by the control unit 20, it is preferable to set t L1 <t L2 ==t Ln However, depending on the relationship between the timing setting of the image data displayed by the display device 10 and the number of divisions of one frame (total number of subframe periods) n, it may be possible to divide the image data completely evenly (t D1 +t L1 =t D2 +t L2 ==t Dn +t Ln It is preferable to divide it completely equally, but L1 <t Ln An error may occur within a range that does not deviate from the above relational expression.

[0040] In Example 2-1, the refresh rate of the display device 10 is set to 60 Hz. Also, in Example 2-1, one frame period of 60 fps image data is divided into two sub-frame periods, as shown in Fig. 13. Each sub-frame period is composed of a light-emitting period and a non-light-emitting period, and the control unit 20 (light-emitting control unit 31) controls the drive unit 50 (vertical scanning circuit 13) so that the non-light-emitting period starts at the start of each sub-frame period and the light-emitting period starts at the end of the non-light-emitting period.

[0041] One frame period is t v Then, in Example 2-1, t L1 =(1 / 2)t v *0.10=0.050t v , t L2 =(1 / 2)t v *0.17=0.085t v Therefore, t L1 <t Ln It is as follows.

[0042] In this way, the light-emission control unit 31 controls the vertical scanning circuit 13 so that the duty ratio of the first subframe period in each frame period is smaller than the duty ratio of at least the last subframe period. Because each frame period is divided into two subframe periods at a refresh rate of 60 Hz, the apparent refresh rate is 120 Hz. Since flicker is barely noticeable when driven at 120 Hz, it can be said that flicker is suppressed in Example 2-1. Furthermore, compared to when all subframe periods are driven at a duty ratio of 17%, the subframe period immediately before the display image data switches (subframe period 1 in Example 2-1) has a duty ratio of 10%, resulting in a longer non-emission period of 90%. The longer non-emission period immediately before the display image data switches can further reduce blurring, which occurs when an image is averaged out due to the persistence of vision in human vision.

[0043] Furthermore, as a result of the inventor's investigation, it was found that when a light emitting period is provided after a non-light emitting period in a sub-frame period, the suppression effect is enhanced if the period during which the display image data is changed between two consecutive frame periods is 3 msec or more. The period during which the display image data is changed between two consecutive frame periods is the period from the end of the light emitting period of the last sub-frame period to the start of light emission of the first sub-frame period of the next frame period. More specifically, the period during which the vertical synchronization signal is disabled between two consecutive frame periods is called t vsoff In this case, t D1 +t vsoff ≧3 msec. D1 is the duty ratio of the first subframe period, R d1 When t D1 =t v / (n*R d1 ) However, in display devices, it is usually vsoff is on the order of 0.01 msec (t vsoff <<3msec), so t D1 It is preferable to control the time so as to satisfy t ≧ 3 msec. D1 =7.5msec.

[0044] In Example 2-1, if the user wishes to change the brightness setting, the setting can be made in the same manner as described in Example 1-1. To increase the brightness, the intensity of the light emitting pulse is increased, and the light emitting period t L1 The light emission period of the subframe period other than the first subframe period (t of the subframe period 2 in the case of Example 2-1) is extended. L2 ) can be lengthened. These methods may be combined to set the brightness. To lower the brightness, the intensity of the light emitting pulse can be reduced, or the light emitting period t L1 The light emission period of the subframe period other than the first subframe period (t of the subframe period 2 in the case of Example 2-1) is shortened. L2) can be considered. These methods may be combined. In any case, in order to obtain the effect of the second embodiment, it is necessary to shorten t L1 <t Ln must be met. (Third embodiment) The third embodiment will be described below, but matters not mentioned in the third embodiment may follow the first or second embodiment. In the third embodiment, the control unit 20 may control the drive unit 50 so that each subframe period is composed of a first non-light-emitting period, a light-emitting period, and a second non-light-emitting period. The control unit 20 may also control the drive unit 50 so that the first non-light-emitting period starts at the start of each subframe, the light-emitting period starts at the end of the first non-light-emitting period, and the second non-light-emitting period ends at the end of the light-emitting period. The control unit 20 may also control the drive unit 50 so that the duty ratio of the first subframe period and the duty ratio of the last subframe period in each unit frame are different.

[0045] 14 illustrates an example of the operation of one frame period tV in the display device 10 of the third embodiment. The control unit 20 sets the lengths of the first non-emission period, the emission period, and the second non-emission period in the k-th (k is 1 to n) subframe as t Dk,1 , t Lk , t Dk,2 When we define t D1,2 +t D2,1 <t Dn,2 +t D1,1 The driving unit 50 can be controlled to satisfy the following. Example 3-1 The control unit 20 (from another point of view, the TG 30 or the light emission pulse generation unit 33) can generate the light emission control signal 21 so as to divide one frame (unit frame) period of the image data into a plurality of (in other words, n) subframe periods equally in time. The first non-light emission period, the light emission period, and the second non-light emission period of the subframe period 1, which is the first subframe, are respectively designated as t D1,1 , t L1 , t D1,2Similarly, the first non-light emitting period, the light emitting period, and the second non-light emitting period of the kth subframe period k (k is an integer of 1 or more and n or less) are expressed as t Dk,1 , t Lk , t Dk,2 Since one frame is divided into multiple subframe periods evenly in time, t D1,1 +t L1 +t D1,2 =t D2,1 +t L2 +t D2,2 ==t Dn,1 +t Ln +t Dn,2 In the second embodiment, t D1,2 +t D2,1 <t Dn,2 +t D1,1 In order to simplify the control by the control unit 20, it is preferable to set t D1,2 +t D2,1 ==t D(n-1),2 +t Dn,1 <t Dn,2 +t D1,1 However, depending on the relationship between the timing setting of the image data displayed by the display device 10 and the number of divisions of one frame (total number of subframe periods) n, it may be possible to divide the image data completely evenly (t D1,1 +t L1 +t D1,2 =t D2,1 +t L2 +t D2,2 ==t Dn,1 +t Ln +t Dn,2 It is preferable to divide it completely equally, but D1,2 +t D2,1 <t Dn,2 +t D1,1 An error may occur within a range that does not deviate from the above relational expression.

[0046] In Example 3-1, as shown in FIG. 15 , the refresh rate of the display device 10 is set to 60 Hz. One frame period of 60 fps image data is divided into two sub-frame periods. The drive unit 50 (vertical scanning circuit 13) is controlled by the control unit 20 (light-emission control unit 31), with each sub-frame period consisting of a first non-light-emitting period, a light-emitting period, and a second non-light-emitting period. The control unit 20 (light-emission control unit 31) also controls the drive unit 50 (vertical scanning circuit 13) so that the first non-light-emitting period starts at the start of each sub-frame, the light-emitting period starts at the end of the first non-light-emitting period, and the second non-light-emitting period starts at the end of the light-emitting period.

[0047] One frame period is t v Then, in Example 3-1, t D1,2 +t D2,1 =(1 / 2)t v *0.20+(1 / 2)t v *0.70=0.450t v , t Dn,2 +t D1,1 =(1 / 2)t v *0.20+(1 / 2)t v *0.63=0.415t v Therefore, t D1,2 +t D2,1 <t Dn,2 +t D1,1 It is as follows.

[0048] In this way, the light-emission control unit 31 can control the driver 50 so that the time from the end of the light-emission period of the last subframe in one frame period to the start of the light-emission period of the first subframe in the next frame (i.e., the non-light-emission period between consecutive frame periods) is longer than the time from the end of the light-emission period of one subframe in one frame to the start of the light-emission period of the next subframe (i.e., the non-light-emission period between consecutive light-emission periods within a frame period). Because each frame period is divided into two subframe periods at a refresh rate of 60 Hz, the apparent refresh rate is 120 Hz. Since flicker is barely noticeable with 120 Hz driving, it can be said that flicker is suppressed in Example 3-1. Furthermore, because the non-light-emission period between consecutive frame periods is longer than the non-light-emission period between consecutive light-emission periods within a frame period, blurring caused by the averaging effect of human vision due to the persistence of vision can be further suppressed.

[0049] Furthermore, as a result of the inventor's investigation, it was found that when a sub-frame period is composed of a first non-light emitting period, a light emitting period, and a second non-light emitting period, the suppression effect is enhanced if the period during which the display image data is changed between two consecutive frame periods is 3 msec or more. The period during which the display image data is changed between two consecutive frame periods is the period from the end of the light emitting period of the last sub-frame period to the start of light emission of the first sub-frame period of the next frame period. More specifically, the period during which the vertical synchronization signal is disabled between two consecutive frame periods is called t vsoff In this case, t Dn,2 +t D1,1 +t vsoff However, in a display device, t vsoff is on the order of 0.01 msec (t vsoff <<3msec), so t Dn,2 +t D1,1 It is preferable to control the time so as to satisfy t ≧ 3 msec. D1 =7.5msec.

[0050] In Example 3-1, if the user wishes to change the brightness setting, the setting can be made in the same manner as described in Example 1-1. To increase the brightness, the intensity of the light emitting pulse is increased, and the light emitting period t L1 The light emission period of the subframe period other than the first subframe period (t of the subframe period 2 in the case of Example 3-1) is extended. L2 ) of the first subframe period (subframe period 1 in the case of Example 3-1). L1 The light emission period of the subframe period other than the first subframe period (t of the subframe period 2 in the case of Example 3-1) is shortened. L2 ) can be considered. These methods may be combined. In any case, in order to obtain the effect of the third embodiment, it is necessary to shorten t D1,2 +t D2,1 <t Dn,2 +t D1,1 must be met.

[0051] The display devices according to the first to third embodiments can divide one frame into a plurality of subframes and adjust the duty ratio of the plurality of subframes, thereby improving the degree of freedom in adjusting the effective brightness.

[0052] The brightness level setting unit 32 may set the brightness level based on the image data. More specifically, the brightness level setting unit 32 may calculate the brightness of the entire image data and set the brightness level based on the brightness of the entire image data (i.e., supply the brightness level to the light emitting pulse generating unit 33).

[0053] The display device 10 or a display device incorporating the display device 10 may include a measurement unit that measures the luminance around the display device 10. The control unit 20 may determine the duty ratio of each subframe period according to the output of the measurement unit (the luminance measured by the measurement unit). This configuration can improve the immediacy of luminance adjustment. If a long time passes between obtaining information indicating the ambient luminance and adjusting the luminance, the control unit is less responsive to sudden changes in the ambient luminance (for example, when a car enters or exits a tunnel, or when a light is turned on or off indoors). Therefore, it is necessary to adjust the luminance quickly. It is advantageous to have the control unit determine the duty ratio according to the ambient luminance obtained from the measurement unit, and adjust the duty ratio of the subframe period according to the determination after the end of the first subframe period of the frame period. (Example 3-2) 16 shows a configuration in which a control unit 20 receives ambient luminance information in a display device having a measurement unit that measures the ambient luminance of a display device 10. The control unit 20 has a receiving unit 41 that receives the ambient luminance information, receives the ambient luminance information, which is information about the ambient luminance measured by the measurement unit, and sends a signal of the ambient luminance information to a light-emission control unit 31. The light-emission control unit 31 sets a luminance level in accordance with the received luminance information, separately from the luminance setting information provided by the receiving unit 40 that receives luminance setting information. When both luminance setting information from the receiving unit 40 and ambient luminance information from the receiving unit 41 are provided, the luminance level setting unit 32 can set the luminance level in accordance with both of them.

[0054] FIG. 17 shows an example of the operation of Example 3-2. In the example of FIG. 17, the light emission control unit 31 (brightness level setting unit 32) determines to lower the brightness level (darken the displayed image) in accordance with the received ambient brightness information. In this example, the brightness level setting unit 32 processes the received ambient brightness information and can lower the brightness level by the end of brightness level period 2. The light emission pulse generation unit 33 changes the duty ratio of subframe periods 3 and 4 in accordance with the setting of the brightness level. Even after the change, t Ln <t L1The duty ratio is set to satisfy t D4 = 3.3 msec, so t Dn ≥ 3 msec. This allows for both flicker and blurring to be suppressed even when brightness is adjusted.

[0055] Hereinafter, examples of the configuration and application of the above display device will be described.

[0056] FIG. 18 is a cross-sectional schematic diagram showing an example of a display device. FIG. 18(a) shows an example of a pixel, which is a component of a display device 10. The pixel has sub-pixels 10. The sub-pixels are divided into 10R, 10G, and 10B based on their light emission. The emitted colors may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the sub-pixels may be selectively transmitted or color-converted using a color filter or the like. Each sub-pixel has a reflective electrode 2, which is a first electrode, on an interlayer insulating layer 1, an insulating layer 3 covering the edge of the reflective electrode 2, an organic compound layer 4 covering the first electrode and the insulating layer, a transparent electrode 5, a protective layer 6, and a color filter 7.

[0057] A transistor and a capacitor may be disposed below or inside the interlayer insulating layer 1. The transistor and the first electrode may be electrically connected via a contact hole or the like (not shown).

[0058] The insulating layer 3 is also called a bank or pixel separation film. It covers the edges of the first electrode and surrounds the first electrode. The part where the insulating layer is not provided contacts the organic compound layer 4 and becomes the light-emitting region.

[0059] The organic compound layer 4 includes a hole injection layer 41 , a hole transport layer 42 , a first light-emitting layer 43 , a second light-emitting layer 44 , and an electron transport layer 45 .

[0060] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0061] The protective layer 6 reduces the penetration of moisture into the organic compound layer. Although the protective layer is illustrated as a single layer, it may be a multi-layer. Each layer may be an inorganic compound layer and an organic compound layer.

[0062] The color filters 7 are divided into 7R, 7G, and 7B depending on their colors. The color filters may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters. The color filters may be formed on a protective layer 6. Alternatively, the color filters may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0063] The display device 100 in FIG. 18(b) can be configured with a display device 10. The display device 100 includes an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided with an insulating layer 12 on top of it. An active element 18 such as a TFT is disposed on the insulating layer, and a gate electrode 13, a gate insulating film 14, and a semiconductor layer 15 of the active element are disposed on top of it. The TFT 18 also includes the semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. An anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20 provided in the insulating film.

[0064] The electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element 26 and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the embodiment shown in Figure 18(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.

[0065] 18(b), the organic compound layer 22 is illustrated as a single layer, but the organic compound layer 22 may be a multi-layer structure. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element.

[0066] In the display device 100 of FIG. 18(b), transistors are used as switching elements, but other switching elements may be used instead.

[0067] The transistors used in the display device 100 of Fig. 18(b) are not limited to transistors using a single-crystal silicon wafer, but may also be thin-film transistors having an active layer on an insulating surface of a substrate. Examples of active layers include non-single-crystal silicon such as single-crystal silicon, amorphous silicon, and 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.

[0068] The transistors included in the display device 100 of Fig. 18(b) may be formed within a substrate such as a Si substrate. Here, "formed within a substrate" means that the transistors are fabricated by processing the substrate itself, such as a Si substrate. In other words, having a transistor within a substrate can be seen as the substrate and the transistor being integrally formed.

[0069] The organic light-emitting element according to this embodiment has its emission brightness controlled by a TFT, which is an example of a switching element. By providing multiple organic light-emitting elements on a surface, an image can be displayed based on the emission brightness of each element. 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 referred to as "inside the substrate." Whether to provide a transistor in the substrate or to use a TFT is determined by the size of the display unit. For example, for a display size of about 0.5 inches, it is preferable to provide the organic light-emitting element on a Si substrate.

[0070] FIG. 19 is a schematic diagram illustrating an example of a display device according to this embodiment. The display device 1000 may include 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. The touch panel 1003 and the display panel 1005 are connected by flexible printed circuits FPCs 1002 and 1004. Transistors are printed on the circuit board 1007. The battery 1008 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 panel 1005 may be configured as a display device 10.

[0071] The display device according to this embodiment may have color filters having red, green, and blue colors, which may be arranged in a delta arrangement.

[0072] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display. The display device may include a processing unit that processes information and a display device 10 configured to display information generated by the information processing unit.

[0073] The display device according to this embodiment may be used as a display unit of 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. The imaging 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 imaging device or a display unit disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0074] 20(a) is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 may have a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may include a display device 10. In this case, the display device 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 speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0075] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. 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 also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0076] FIG. 20(b) is a schematic diagram illustrating an example of an electronic device according to 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 may be a biometric recognition unit that recognizes a fingerprint to unlock the device, 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, a laptop computer, etc. The display unit 1201 may be configured with a display device 10.

[0077] Fig. 21 is a schematic diagram showing an example of a display device according to 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 display unit 1302 can be configured with a display device 10.

[0078] It has a frame 1301 and a base 1303 that supports a display unit 1302. The base 1303 is not limited to the form shown in Fig. 21(a). The bottom side of the frame 1301 may also serve as the base.

[0079] 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.

[0080] FIG. 21(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in 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 first display unit 1311 and the second display unit 1312 can be configured as a display device 10. The first display unit 1311 and the second display unit 1312 may be a single seamless display unit. The first display unit 1311 and the second display unit 1312 can be separated by the bending point. The first display unit 1311 and the second display unit 1312 may each display different images, or the first and second display units may display a single image.

[0081] An application example of the display device of each of the above-described embodiments will be described with reference to Fig. 22. The display device can be applied to a system that can be attached as a wearable device, such as smart glasses, an HMD, or a smart contact lens. An image capturing and displaying device used in such an application example includes an image capturing device capable of photoelectrically converting visible light and a displaying device capable of emitting visible light.

[0082] 22(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. A display device 10 may be disposed on the back side of the lens 1601.

[0083] 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 operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0084] FIG. 22(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612. The control device 1612 is equipped with an imaging device equivalent to the imaging device 1602 and a display device 10. A lens 1611 is formed with an optical system for projecting light emitted by a display device within the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the imaging device and the display device 10 and controls the operation of the imaging device and the display device 10. The control device may also include a gaze detection unit for detecting the gaze of the wearer. Infrared light may be used for gaze detection. The infrared light emitter emits infrared light toward the eyeball of a user gazing at a displayed image. An imaging unit with a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. A reduction unit for reducing light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality.

[0085] The gaze of the user relative to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be used for gaze detection using an image of the eyeball. One example is a gaze detection method based on the Purkinje image formed by reflection of irradiated light on the cornea.

[0086] More specifically, gaze detection processing is performed based on the pupil-corneal reflex method, which calculates a gaze vector representing the direction (rotation angle) of the eyeball based on the pupil image and Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0087] A display device according to an embodiment of the present invention may have an imaging device having a light receiving element, and may control the image displayed on the display device based on information about the user's line of sight from the imaging device.

[0088] Specifically, the display device determines a first display area on which the user gazes and a second display area other than the first display area based on the line-of-sight information. The first display area and the second display area may be determined by a control device of the display device, or may be determined by an external control device and received. In the display area of ​​the display device, the display resolution of the first display area may be controlled to be higher than the display resolution of the second display area. In other words, the resolution of the second display area may be lower than that of the first field of view area.

[0089] The display area includes a first display area and a second display area different from the first display area, and a high-priority area 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 determined by an external control device and received. 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.

[0090] Note that AI may be used to determine the first display area and the area 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 actual direction in which the eyeball in the image was looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0091] When display control is performed based on visual recognition detection, the smart glasses can be preferably applied to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0092] The present specification and drawings include the following disclosure. (Document name) Claims (Item 1) A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that the duty ratio of the last subframe period is smaller than the duty ratio of the first subframe period in each unit frame. A display device characterized by: (Item 2) the control unit controls the drive unit so that each subframe period is composed of a light-emitting period and a non-light-emitting period, the light-emitting period starts at the start of each subframe period, and the non-light-emitting period starts at the end of the light-emitting period. 2. The display device according to item 1, (Item 3) the control unit controls the drive unit so that, in each unit frame, a duty ratio of the last subframe period among the plurality of subframe periods is smaller than duty ratios of subframe periods other than the last subframe period. 3. The display device according to item 2, (Item 4) the control unit controls the drive unit so that the non-light emitting period of the last sub-frame period in each frame period is 3 msec or longer. 4. The display device according to item 2 or 3, (Item 5) A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that each subframe period is composed of a light-emitting period and a non-light-emitting period, the non-light-emitting period starts at the start of each subframe period, and the light-emitting period starts at the end of the non-light-emitting period; the control unit controls the drive unit so that, in each unit frame, the duty ratio of the first subframe period is smaller than the duty ratio of at least the last subframe period. A display device characterized by: (Item 6) the control unit controls the drive unit so that, in each unit frame, a duty ratio of the first subframe period among the plurality of subframe periods is smaller than duty ratios of subframe periods other than the first subframe period. 6. The display device according to item 5, (Item 7) the control unit controls the drive unit so that the non-light emitting period of the first sub-frame period in each frame period is 3 msec or longer. 7. The display device according to item 5 or 6, (Item 8) A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that each subframe period is composed of a first non-light-emitting period, a light-emitting period, and a second non-light-emitting period, the first non-light-emitting period starts at the start of each subframe, the light-emitting period starts at the end of the first non-light-emitting period, and the second non-light-emitting period starts at the end of the light-emitting period; When the lengths of the first non-light emitting period, the light emitting period, and the second non-light emitting period in the k-th subframe (k is 1 to n) are defined as tDk,1, tLk, and tDk,2, respectively, the control unit tD1,2+tD2,1 <tDn,2+tD1,1 and controlling the driving unit so as to satisfy the above. A display device characterized by: (Item 9) The control unit controls the drive unit so that tDk,1 is equal for k=1 to n-1, tLk is equal for k=1 to n-1, and tDk,2 is equal for k=1 to n-1. 9. The display device according to item 8, (Item 10) The control unit controls the drive unit so that tD1,2+tD2,1 is 3 msec or more. 10. The display device according to item 9, (Item 11) the driving unit supplies a signal corresponding to a luminance signal to a plurality of pixels constituting the pixel array. 11. A display device according to any one of items 1 to 10. (Item 12) the signal has a voltage corresponding to the luminance signal; Item 12. A display device according to item 11. (Item 13) the driving section supplies the signal to each of the plurality of pixels once in each unit frame period. 13. The display device according to item 11 or 12. (Item 14) a measurement unit that measures the luminance around the pixel array; the control unit determines a duty ratio for each subframe period in accordance with the output of the measurement unit. Item 14. The display device according to item 13. (Item 15) the control unit determines a duty cycle according to the output of the measurement unit, and then, after the end of a first subframe period in a unit frame, changes the duty cycles of the remaining subframes to the determined duty cycle. Item 15. A display device according to item 14. (Item 16) an information processing unit that processes information; A display device according to any one of items 1 to 15 configured to display information generated by the information processing unit; A display device comprising: (Item 17) 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; The display unit includes a display device according to any one of items 1 to 15 configured to display an image captured by the imaging element. A photoelectric conversion device characterized by: (Item 18) A display unit is provided in the housing, and a communication unit is provided in the housing and communicates with an external device. The display unit includes a display device according to any one of items 1 to 15. An electronic device characterized by: (Item 19) 1. A wearable device having a display device for displaying an image, The display device includes a display device according to any one of items 1 to 15. A wearable device characterized by:

[0093] The invention is not limited to the above-described embodiments, and various changes and modifications can be made 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]

[0094] 10: display device, 11: pixel, 12: pixel array, 13: vertical scanning circuit, 14: signal output circuit, 15: scanning line group, 16: signal line, 20: control unit, 50: driving unit

Claims

1. A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that the duty ratio of the last sub-frame period in each unit frame is smaller than the duty ratio of the first sub-frame period. A display device characterized by:

2. the control unit controls the drive unit so that each subframe period is composed of a light-emitting period and a non-light-emitting period, the light-emitting period starts at the start of each subframe period, and the non-light-emitting period starts at the end of the light-emitting period.

2. The display device according to claim 1.

3. the control unit controls the drive unit so that, in each unit frame, a duty ratio of the last subframe period among the plurality of subframe periods is smaller than duty ratios of subframe periods other than the last subframe period.

3. The display device according to claim 2.

4. the control unit controls the drive unit so that the non-light emitting period of the last sub-frame period in each frame period is 3 msec or longer.

3. The display device according to claim 2.

5. A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that each subframe period is composed of a light-emitting period and a non-light-emitting period, the non-light-emitting period starts at the start of each subframe period, and the light-emitting period starts at the end of the non-light-emitting period; the control unit controls the drive unit so that, in each unit frame, the duty ratio of the first subframe period is smaller than the duty ratio of at least the last subframe period. A display device characterized by:

6. the control unit controls the drive unit so that, in each unit frame, a duty ratio of the first subframe period among the plurality of subframe periods is smaller than duty ratios of subframe periods other than the first subframe period.

6. A display device according to claim 5.

7. the control unit controls the drive unit so that the non-light emitting period of the first sub-frame period in each frame period is 3 msec or longer.

6. A display device according to claim 5.

8. A display device comprising: a pixel array; a driver that drives the pixel array; and a controller that controls the driver, the control unit controls the drive unit so that each unit frame period is made up of a plurality of subframe periods and a duty ratio in each subframe period is controlled; the control unit controls the drive unit so that each subframe period is composed of a first non-light-emitting period, a light-emitting period, and a second non-light-emitting period, the first non-light-emitting period starts at the start of each subframe, the light-emitting period starts at the end of the first non-light-emitting period, and the second non-light-emitting period starts at the end of the light-emitting period; The control unit sets the lengths of the first non-light emitting period, the light emitting period, and the second non-light emitting period in the k-th (k is 1 to n) subframe as t Ｄｋ，１ , t Ｌｋ , t Ｄｋ，２ When we define t Ｄ１，２ +t Ｄ２，１ <t Ｄｎ，２ +t Ｄ１，１ and controlling the driving unit so as to satisfy the above. A display device characterized by:

9. The control unit is configured to Ｄｋ，１ are equal, and t for k=1 to n-1 Ｌｋ are equal, and t for k=1 to n-1 Ｄｋ，２ and controlling the drive unit so that 9. A display device according to claim 8.

10. The control unit Ｄ１，２ +t Ｄ２，１ The driving unit is controlled so that the time is 3 msec or more.

10. The display device according to claim 9.

11. the driving unit supplies a signal corresponding to a luminance signal to a plurality of pixels constituting the pixel array.

2. The display device according to claim 1.

12. the signal has a voltage corresponding to the luminance signal; 12. A display device according to claim 11.

13. the driving section supplies the signal to each of the plurality of pixels once in each unit frame period; 12. A display device according to claim 11.

14. a measurement unit that measures the luminance around the pixel array; the control unit determines a duty ratio for each subframe period in accordance with the output of the measurement unit.

14. A display device according to claim 13.

15. the control unit determines a duty cycle according to the output of the measurement unit, and then, after the end of a first subframe period in a unit frame, changes the duty cycles of the remaining subframes to the determined duty cycle.

15. A display device according to claim 14.

16. an information processing unit that processes information; a display device according to any one of claims 1 to 15, configured to display information generated by the information processing unit; A display device comprising:

17. 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; The display unit includes the display device according to any one of claims 1 to 15, configured to display an image captured by the imaging element. A photoelectric conversion device characterized by:

18. A display unit is provided in the housing, and a communication unit is provided in the housing and communicates with an external device. The display unit includes a display device according to any one of claims 1 to 15. An electronic device characterized by:

19. 1. A wearable device having a display device for displaying an image, The display device comprises a display device according to any one of claims 1 to 15. A wearable device characterized by:

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