Display device

Abstract

A display device (100) includes a display part (DA) provided with a first display region (1) and a second display region (2). In plan view, the occupancy rate of light-emitting regions included in the second display region in the display part is smaller than the occupancy rate of light-emitting regions included in the first display region. The second display region, compared with a virtual display region obtained by reducing the area of each light-emitting region in the first display region in plan view at the same area ratio, has a smaller difference from the first display region in the temporal change of light chromaticity obtained when all of the light-emitting regions have emitted light. A reduction ratio of the area of each light-emitting region in the second display region to the area of each light-emitting region in the first display region in plan view is determined so as to reduce the difference between the first display region and the second display region in the temporal change of light chromaticity obtained when all of the light-emitting regions have emitted light.

Description

display device

[0001] The present disclosure relates to a display device including a light-emitting element.

[0002] Patent Literature 1 discloses a technology for forming a light-transmitting region in a display unit, in which the area of ​​a light-emitting region is smaller than that of a normal display region, and light can pass through the light-transmitting region between the light-emitting regions. The display unit enables display in the light-transmitting region and allows light to pass through the light-transmitting region. Such a display unit is applied, for example, to a display unit provided with a camera unit formed in a position overlapping the display unit and capturing images using imaging light transmitted through the display unit.

[0003] "Blue-Emitting InP / GaP / ZnS Quantum Dots with Enhanced Stability by Siloxane Capping: Implication for Electroluminescent Devices" (ACS Appl. Nano Mater. 2022, 5, 2801-2811)

[0004] Because the light-emitting regions in the translucent region have different areas than the normal display region, the rate at which the luminance of each light-emitting region in the translucent region deteriorates over time differs from the rate at which the luminance of each light-emitting region in the normal display region deteriorates over time. This may result in a difference in the change in chromaticity over time between the normal display region and the translucent region. Therefore, in a display device such as that disclosed in Patent Document 1, the deterioration of each light-emitting region over time may result in a difference in color between the normal display region and the translucent region, potentially resulting in a decrease in display quality.

[0005] A display device according to one aspect of the present disclosure is a display device including a display unit having a first display region and a second display region, each having a plurality of light-emitting regions, wherein, in a planar view, the occupancy rate of the light-emitting regions included in the second display region in the display unit is smaller than the occupancy rate of the light-emitting regions included in the first display region, and the second display region has a smaller difference in the change in chromaticity of light over time obtained when all of the light-emitting regions emit light compared to a virtual display region obtained by reducing the area of ​​each light-emitting region of the first display region in a planar view by the same area ratio.

[0006] Furthermore, a display device according to one aspect of the present disclosure is a display device including a display unit having a first display region and a second display region, each having a plurality of light-emitting regions, wherein, in a planar view, the occupancy rate of the light-emitting regions included in the second display region in the display unit is smaller than the occupancy rate of the light-emitting regions included in the first display region, and the reduction ratio of the area of ​​each light-emitting region of the second display region relative to the area of ​​each light-emitting region of the first display region in a planar view is determined so that the difference in the change over time in the chromaticity of the light obtained when all of the light-emitting regions emit light between the first display region and the second display region is small.

[0007] According to a configuration according to one aspect of the present disclosure, the difference in chromaticity between the first display area and the second display area caused by deterioration over time of the luminance of each light-emitting area of ​​the display unit is reduced, thereby improving display quality.

[0008] 1 is a schematic plan view of a display device according to embodiment 1. FIG. 2 is an enlarged plan view of a first display region of the display device according to embodiment 1. FIG. 3 is an enlarged plan view of a second display region of the display device according to embodiment 1. FIG. 4 is a schematic side cross-sectional view of the display device according to embodiment 1. FIG. 5 is an enlarged plan view of a virtual display region of a display device according to a comparative example. FIG. 6 is a graph showing the luminance degradation and chromaticity change over time of each light-emitting element in the first display region of the display device according to example 1. FIG. 7 is a graph showing the luminance degradation and chromaticity change over time of each light-emitting element in the virtual display region of the display device according to the comparative example. FIG. 8 is a graph showing the luminance degradation and chromaticity change over time of each light-emitting element in the second display region of the display device according to example 1. FIG. 9 is an enlarged plan view of a second display region of a display device according to embodiment 2. FIG. 10 is a graph showing the luminance degradation and chromaticity change over time of each light-emitting element in the first display region of the display device according to example 2. FIG. 11 is a graph showing the luminance degradation and chromaticity change over time of each light-emitting element in the second display region of the display device according to example 2. FIG. 12 is an enlarged plan view of a second display region of a display device according to embodiment 3. 10 is a graph showing the deterioration of luminance and chromaticity over time of each light-emitting element in a first display region of a display device according to Example 3. FIG. 11 is a graph showing the deterioration of luminance and chromaticity over time of each light-emitting element in a second display region of a display device according to Example 3. FIG. 12 is an enlarged plan view of a first display region of a display device according to embodiment 4. FIG. 13 is an enlarged plan view of a second display region of a display device according to embodiment 4. FIG. 14 is a graph showing the deterioration of luminance and chromaticity over time of each light-emitting element in a first display region of a display device according to Example 4. FIG. 15 is a graph showing the deterioration of luminance and chromaticity over time of each light-emitting element in a second display region of a display device according to Example 4.

[0009] [Embodiment 1] <Display Device: Overview> Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that in each drawing, similar components are denoted by the same reference numerals and description thereof will be omitted.

[0010] FIG. 1 is a schematic plan view of a display device 100 according to this embodiment. The display device 100 is a device that can be used, for example, as a display for a television or a smartphone. The display device 100 includes a display unit DA and a frame unit NA formed around the periphery of the display unit DA. The display device 100 displays an image on the display unit DA by controlling light emission from each of a plurality of light-emitting elements (described later) formed in the display unit DA. Drivers and the like for driving each of the plurality of light-emitting elements of the display unit DA may be formed in the frame unit NA.

[0011] The display unit DA of the display device 100 includes a first display area 1 and a second display area 2. In this embodiment, the second display area 2 is formed in a substantially circular shape in a plan view at a position surrounded by the first display area 1.

[0012] <Display Device: First Display Region> The first display region 1 will be described with reference to Fig. 2. Fig. 2 is an enlarged plan view showing the first display region 1 of the display unit DA of the display device 100. As shown in Fig. 2, the display device 100 has a plurality of blue light-emitting elements 11, a plurality of green light-emitting elements 12, and a plurality of red light-emitting elements 13 in the first display region 1.

[0013] The display device 100 extracts blue light from the blue light-emitting element 11, green light from the green light-emitting element 12, and red light from the red light-emitting element 13 from the first display region 1. Therefore, the first display region 1 functions as a normal display region for full-color display.

[0014] In this embodiment, blue light refers to light having a central emission wavelength in a wavelength band of, for example, 380 nm or more and 500 nm or less. Green light refers to light having a central emission wavelength in a wavelength band of, for example, more than 500 nm and less than 600 nm. Red light refers to light having a central emission wavelength in a wavelength band of, for example, more than 600 nm and less than 780 nm.

[0015] The first display region 1 has a plurality of blue light-emitting regions 21 as first light-emitting regions. The blue light-emitting regions 21 are the same as the regions that overlap with the light-emitting layers of the blue light-emitting elements 11 in a plan view. The blue light-emitting regions 21 emit light that includes blue light, which is light having a first wavelength.

[0016] The first display region 1 also has a plurality of green light-emitting regions 22 as second light-emitting regions. The green light-emitting regions 22 are the same as the regions that overlap with the light-emitting layers of the green light-emitting elements 12 in a plan view. The green light-emitting regions 22 emit light that includes green light, which is light having a second wavelength that is longer than the first wavelength.

[0017] Furthermore, the first display region 1 has a plurality of red light-emitting regions 23 as fifth light-emitting regions. The red light-emitting regions 23 are the same as the regions that overlap with the light-emitting layers of the red light-emitting elements 13 in a plan view. The red light-emitting regions 23 emit light containing red light, which is light having a third wavelength longer than the second wavelength.

[0018] <Display Device: Second Display Region> The second display region 2 will be described with reference to Fig. 3. Fig. 3 is an enlarged plan view showing the second display region 2 of the display unit DA of the display device 100. As shown in Fig. 3, the display device 100 includes a plurality of blue light-emitting elements 31, a plurality of green light-emitting elements 32, and a plurality of red light-emitting elements 33 in the second display region 2. The display device 100 performs display in the second display region 2 by controlling the blue light from the blue light-emitting elements 31, the green light from the green light-emitting elements 32, and the red light from the red light-emitting elements 33.

[0019] The second display region 2 has a plurality of blue light-emitting regions 41 as third light-emitting regions. The blue light-emitting regions 41 are the same as the regions that overlap with the light-emitting layers of the blue light-emitting elements 31 in a plan view. The blue light-emitting regions 41 emit light that includes blue light, which is light having a first wavelength.

[0020] The second display region 2 also has a plurality of green light-emitting regions 42 as fourth light-emitting regions. The green light-emitting regions 42 are the same as the regions that overlap with the light-emitting layers of the green light-emitting elements 32 in a plan view. The green light-emitting regions 42 emit light that includes green light, which is light having a second wavelength that is longer than the first wavelength.

[0021] Furthermore, the second display region 2 has a plurality of red light-emitting regions 43 as sixth light-emitting regions. The red light-emitting regions 43 are the same as the regions that overlap with the light-emitting layers of the red light-emitting elements 33 in a plan view. The red light-emitting regions 43 emit light containing red light, which is light having a third wavelength that is longer than the second wavelength.

[0022] The blue light-emitting region 41, the green light-emitting region 42, and the red light-emitting region 43 have the same configuration as the blue light-emitting region 21, the green light-emitting region 22, and the red light-emitting region 23, except that they have smaller areas in a planar view. Therefore, in a planar view, the occupancy rate of the light-emitting regions included in the second display region 2 in the display unit DA is smaller than the occupancy rate of the light-emitting regions included in the first display region 1. In other words, the ratio of the area of ​​the light-emitting regions included in the second display region 2 to the total area of ​​the display unit DA in a planar view is smaller than the ratio of the area of ​​the light-emitting regions included in the first display region 1 to the total area of ​​the display unit DA in a planar view. For example, in a planar view, the total area of ​​the light-emitting regions included in the second display region 2 may be smaller than the total area of ​​the light-emitting regions included in the first display region 1.

[0023] In the present disclosure, the "area of ​​the light-emitting region" refers to the area of ​​the light-emitting region in a planar view of each display device. Furthermore, in this embodiment, it is sufficient that the occupancy rate of the light-emitting region of the second display region 2 in the display unit DA is smaller than the occupancy rate of the light-emitting region of the first display region 1 in a planar view. In other words, as long as the above is satisfied, the area of ​​the light-emitting region of a portion of the second display region 2 according to this embodiment may be larger than the area of ​​a portion of the light-emitting region of the first display region 1.

[0024] In this embodiment, the area ratio of the blue light-emitting region 41 to the blue light-emitting region 21 is greater than the area ratio of the green light-emitting region 42 to the green light-emitting region 22 and the area ratio of the red light-emitting region 43 to the red light-emitting region 23. In addition, the area ratio of the green light-emitting region 42 to the green light-emitting region 22 is greater than the area ratio of the red light-emitting region 43 to the red light-emitting region 23.

[0025] For example, the area of ​​blue light-emitting region 41 may be 0.6 times the area of ​​blue light-emitting region 21. The area of ​​green light-emitting region 42 may be 0.38 times the area of ​​green light-emitting region 22. The area of ​​red light-emitting region 43 may be 0.24 times the area of ​​red light-emitting region 23.

[0026] The display device 100 also performs full-color display in the second display region 2 by extracting blue light from the blue light-emitting element 31, green light from the green light-emitting element 32, and red light from the red light-emitting element 33 from the second display region 2. The display device 100 may drive each light-emitting element in the second display region 2 at a current density higher than each light-emitting element in the first display region 1. This allows the display device 100 to reduce the difference in luminance between the first display region 1 and the second display region 2, and to reduce the visibility of the boundary between the first display region 1 and the second display region 2.

[0027] <Display Device: Layered Structure: Light-Transmitting Film> The layered structure of the display device 100 according to this embodiment will be described with reference to Fig. 4. Fig. 4 is a schematic side cross-sectional view of the display device 100, and in particular, is an enlarged view of a side cross-section passing through both the first display region 1 and the second display region 2, showing the vicinity of the boundary between the first display region 1 and the second display region 2. The side cross-section shown in Fig. 4 passes through the blue light-emitting element 11 located in the first display region 1 and the blue light-emitting element 31 located in the second display region 2.

[0028] The display device 100 includes a light-transmitting substrate 60, such as a glass substrate or a film substrate. The display device 100 also includes a pixel circuit layer 61 on the substrate 60. The pixel circuit layer 61 includes, in order from the substrate 60 side, a first inorganic interlayer film 62, a second inorganic interlayer film 63, a third inorganic interlayer film 64, a first organic interlayer film 65, a second organic interlayer film 66, and a third organic interlayer film 67, all of which are light-transmitting. The substrate 60, the inorganic interlayer films, and the organic interlayer films described above may be formed in a display unit DA including a first display region 1 and a second display region 2.

[0029] The first inorganic interlayer film 62, the second inorganic interlayer film 63, and the third inorganic interlayer film 64 are formed, for example, by forming an inorganic oxide film or the like by a CVD method, etc. The first organic interlayer film 65, the second organic interlayer film 66, and the third organic interlayer film 67 are formed, for example, by forming an organic coating film having optical transparency, such as polyimide, by a coating method, a photolithography method, etc.

[0030] <Display Device: Stacked Structure: Light-Emitting Element Layer> Furthermore, display device 100 includes a light-emitting element layer 70 above pixel circuit layer 61. Light-emitting element layer 70 includes a plurality of light-emitting elements including, for example, blue light-emitting element 11 and blue light-emitting element 31. Light-emitting element layer 70 includes, in this order from the pixel circuit layer 61 side, a first electrode 71 which is a pixel electrode of each light-emitting element, a first functional layer 72 which includes a light-emitting layer of each light-emitting element, and a common electrode 73 which is formed in common to all the light-emitting elements. For example, blue light-emitting region 21 is formed at a position overlapping with the light-emitting layer of blue light-emitting element 11 in a planar view, and blue light-emitting region 41 is formed at a position overlapping with the light-emitting layer of blue light-emitting element 31 in a planar view.

[0031] The light-emitting element layer 70 may further include a bank layer 74 on the third organic interlayer film 67 of the pixel circuit layer 61 and on the pixel electrodes of each light-emitting element. In this case, openings may be formed in the bank layer 74 at positions overlapping with each sub-pixel in a plan view of the display device 100, and functional layers of each light-emitting element may be formed in the openings. The bank layer 74 may be formed, for example, by forming a light-transmitting organic coating film such as polyimide by a coating method, a photolithography method, or the like.

[0032] <Display Device: Stacked Structure: Conductive Film> Furthermore, in the first display region 1, the pixel circuit layer 61 includes, in order from the substrate 60 side, a first conductive film 81, a semiconductor film 82, a second conductive film 83, a third conductive film 84, and a fourth conductive film 85. The first conductive film 81 is located between the substrate 60 and the first inorganic interlayer film 62. The semiconductor film 82 is located between the first inorganic interlayer film 62 and the second inorganic interlayer film 63. The second conductive film 83 is located between the second inorganic interlayer film 63 and the third inorganic interlayer film 64. The third conductive film 84 is located between the third inorganic interlayer film 64 and the first organic interlayer film 65. The fourth conductive film 85 is located between the first organic interlayer film 65 and the second organic interlayer film 66.

[0033] The first conductive film 81, the second conductive film 83, the third conductive film 84, and the fourth conductive film 85 all have electrical conductivity and may be, for example, a conductive film having light reflectivity including a metal film. Each pixel circuit in the first display region 1 may be formed by forming a thin film transistor using the first conductive film 81, the semiconductor film 82, the second conductive film 83, the third conductive film 84, and the fourth conductive film 85.

[0034] <Display Device: Stacked Structure: Leading Wiring> The pixel circuit layer 61 includes a light-transmitting leading wiring 86 between the second organic interlayer film 66 and the third organic interlayer film 67 in the first display region 1 and the second display region 2. The leading wiring 86 is electrically connected to the fourth conductive film 85 via a contact portion 86C that penetrates the second organic interlayer film 66 in the thickness direction. Furthermore, the first electrode 71 in the second display region 2 is electrically connected to the leading wiring 86 via a contact portion 71C that penetrates the third organic interlayer film 67 in the thickness direction.

[0035] Therefore, the display device 100 is capable of driving not only each light-emitting element in the first display region 1 but also each light-emitting element in the second display region 2 by each pixel circuit in the first display region 1. Each light-emitting element driven via each pixel circuit emits light LR, for example, in a direction from each light-emitting layer toward the common electrode 73. Therefore, each layer on the light-emitting element layer 70 side of the substrate 60 functions as a display panel that performs display in the display unit DA.

[0036] <Display Device: Stacked Structure: Camera Unit> The display device 100 further includes a camera unit CU including an imaging element on the side of the substrate 60 opposite the pixel circuit layer 61, in other words, on the side opposite the display surface of the display panel. The display device 100 includes the camera unit CU at a position overlapping with the second display area 2 in a plan view.

[0037] The camera unit CU is irradiated with imaging light LT, which is external light incident from the display surface side of the display device 100. In particular, the second display region 2 is formed with a light-transmitting member including the lead wiring 86, excluding each pixel electrode. Therefore, the second display region 2 is formed with a light-transmitting region 3 through which the imaging light LT passes from the common electrode 73 to the camera unit CU.

[0038] Therefore, the imaging light LT incident on the light-transmitting region 3 from the display surface side of the display device 100 is taken in by the camera unit CU. In other words, the second display region 2 including the light-transmitting region 3 is a light-receiving display region that takes in external light from between the light-emitting regions.

[0039] From the viewpoint of increasing the proportion of the light-transmitting region 3 in the second display region 2 and more efficiently capturing external light into the camera unit CU, the area of ​​each light-emitting region in the second display region 2 may be smaller than the area of ​​each light-emitting region in the first display region 1. In particular, from the viewpoint of more efficiently capturing external light into the camera unit CU, the area of ​​each light-emitting region in the second display region 2 may be 0.6 times or less the area of ​​each light-emitting region in the first display region 1.

[0040] This allows the display device 100 to use the camera unit CU to capture an image of the display surface side of the substrate 60. Note that the display device 100 may also use the camera unit CU to capture an image of the back side of the display device 100, i.e., the side opposite the display surface of the substrate 60.

[0041] The display device 100 may be manufactured by forming the above-described layers on the substrate 60 in order, and then mounting a camera unit on the lower surface side of the substrate 60 .

[0042] <Virtual Display Area of ​​Display Device According to Comparative Example> In order to evaluate the optical characteristics of the display device 100 according to this embodiment, the optical characteristics of the display devices according to each of the examples and the comparative example are compared. The display device according to Example 1 has the same configuration as the display device 100 according to this embodiment. The display device according to the comparative example has the same configuration as the display device according to Example 1, except that it has a virtual display area 2A instead of the second display area 2.

[0043] The virtual display area 2A will be described with reference to Fig. 5. Fig. 5 is an enlarged plan view showing the virtual display area 2A of the display unit DA of a display device according to a comparative example. The display device according to the comparative example includes a plurality of blue light-emitting elements 31A, a plurality of green light-emitting elements 32A, and a plurality of red light-emitting elements 33A in the virtual display area 2A. The display device according to the comparative example includes a blue light-emitting region 41A, a green light-emitting region 42A, and a red light-emitting region 43A in the virtual display area 2A at positions overlapping with the light-emitting layers of the blue light-emitting elements 31A, the green light-emitting elements 32A, and the red light-emitting elements 33A, respectively.

[0044] The areas of the blue light-emitting region 41A, the green light-emitting region 42A, and the red light-emitting region 43A are the same as the areas of the blue light-emitting region 21, the green light-emitting region 22, and the red light-emitting region 23 reduced by the same ratio. In other words, each light-emitting region in the virtual display region 2A has the same configuration as the light-emitting region in the first display region reduced by the same area ratio. For example, in a plan view, the areas of the blue light-emitting region 41A, the green light-emitting region 42A, and the red light-emitting region 43A are 0.6 times the areas of the blue light-emitting region 21, the green light-emitting region 22, and the red light-emitting region 23.

[0045] <Change in chromaticity over time> The evaluation index for the display devices according to the example and comparative example is the change in chromaticity over time Δu′v′ of light obtained from each position on the display unit DA. Δu′v′ is calculated as follows.

[0046] First, when each display device is shipped, the light obtained from each position on the display unit DA is measured when all light-emitting elements on the display unit DA are illuminated at maximum brightness. This determines the initial values ​​of the tristimulus values ​​X, Y, and Z of the light, in other words, the values ​​at the time of shipment. Next, the light emitted by each light-emitting element and the light obtained from the display unit DA are measured for a predetermined period of time, and the changes over time in the tristimulus values ​​X, Y, and Z at each position on the display unit DA are determined. The tristimulus values ​​X, Y, and Z may be measured by actually measuring the values ​​from the initial values ​​up to several hundred hours after the initial values, and then calculating the values ​​at subsequent times through simulations using these measurement results.

[0047] Next, at each position on the display unit DA, u' and v' at each time are calculated using the tristimulus values ​​X, Y, and Z from the following equations.

[0048] u'=4X / (X+15Y+3Z) v'=9X / (X+15Y+3Z) Then u' ０ Let u' be the initial value, and v' ０ Let v' be the initial value, and u' Ｔ Let u' be the value at time T, and v' Ｔ is the value of v' at time T, and Δu'v' at each position on the display unit DA at time T is calculated using the following formula.

[0049] Δu'v' represents the magnitude of change in chromaticity from the initial value in the display unit DA of the display device. Therefore, the smaller the difference in Δu'v' depending on the position of the display unit DA, the less visible the change in color depending on the position of the display unit DA, and therefore it can be said that the display quality of a display device equipped with the display unit DA is high.

[0050] <Evaluation of the display device according to Example 1> The above-mentioned Δu'v' was measured for each of the display devices according to Example 1 and the comparative example. In particular, Δu'v' was measured in each of the first display region 1 and the second display region 2 for the display device according to Example 1, and Δu'v' was measured in the virtual display region 2A for the display device according to the comparative example. In these measurements, the change over time in luminance from the initial value of each display region of each of the display devices according to Example 1 and the comparative example when the entire display region was displayed in blue, green, and red was also measured.

[0051] The luminance of a display area of ​​a display device when the entire display area is displaying blue, green, and red was measured by measuring the luminance of the display unit DA when all the blue, green, and red light-emitting elements in the display area were emitting light. Therefore, the change in luminance of the display area when the entire display area is displaying blue, green, and red correlates with the change in luminance of the blue, green, and red light-emitting elements in the display area, respectively.

[0052] The brightness of the display area DA of each display device was measured by placing a brightness meter about 40 cm away from the panel, causing the display area DA to emit light, and measuring the intensity of light incident on the camera of the brightness meter from an area about 1 cm in diameter of the display area DA. The light emission of the display area DA was performed by causing each light-emitting element to emit light at 255 (maximum gray level) out of 256 gray levels.

[0053] The measurement results for the display devices according to Example 1 and the comparative example are summarized in Figures 6 to 8. Figure 6 is a graph showing the luminance deterioration over time and the chromaticity change Δu'v' over time in the first display region 1 of the display device according to Example 1. Figure 7 is a graph showing the luminance deterioration over time and the chromaticity change Δu'v' over time in the virtual display region 2A of the display device according to the comparative example. Figure 8 is a graph showing the luminance deterioration over time and the chromaticity change Δu'v' over time in the second display region 2 of the display device according to Example 1.

[0054] 6 to 8, the horizontal axis represents the lighting time (unit time) of each light-emitting element, the left vertical axis represents the change in luminance of each display region over time (ratio from initial luminance), and the right vertical axis represents Δu′v′. In the graphs of the present disclosure, Δu′v′ is indicated by a solid line, and the luminance of the display region when the entire display is in blue, green, or red is indicated by a dotted line, a dashed line, and a dash-dotted line, respectively.

[0055] 6, in the display device according to Example 1, the luminance degradation of the first display region 1 is faster during full-screen blue display than during full-screen green display, and faster during full-screen green display than during full-screen red display. This corresponds to the fact that, in the display device according to Example 1, the luminance degradation over time of the blue light-emitting element 11 is faster than the luminance degradation over time of the green light-emitting element 12, and the luminance degradation over time of the green light-emitting element 12 is faster than the luminance degradation over time of the red light-emitting element 13. Also, as shown in FIG. 6, in the first display region 1 of the display device according to Example 1, the obtained light Δu'v' increases depending on the lighting time.

[0056] The rate of deterioration of the luminance of a light-emitting element over time generally varies depending on the material of the functional layer of the light-emitting element or the area of ​​the light-emitting region. In particular, the smaller the area of ​​the light-emitting region of a light-emitting element, the greater the current density required to obtain the same luminance in the light-emitting element, and therefore the faster the luminance of the light-emitting element tends to deteriorate over time.

[0057] 7 , the luminance degradation of the virtual display region 2A of the display device according to the comparative example is faster than the luminance degradation of the first display region 1 of the display device according to Example 1. This corresponds to the fact that the luminance degradation over time of each light-emitting element in the virtual display region 2A progresses faster than the luminance degradation over time of each light-emitting element in the first display region 1 of the display device according to Example 1. This is because the area of ​​each light-emitting region in the virtual display region 2A is smaller than the area of ​​each light-emitting region in the first display region 1.

[0058] Furthermore, in the display device of the comparative example, the luminance degradation of the virtual display region 2A progresses significantly faster during full-screen blue display than during full-screen green display. This corresponds to the fact that, in the display device of the comparative example, the luminance degradation of the blue light-emitting element 31A progresses significantly faster over time than the luminance degradation of the green light-emitting element 32A and the red light-emitting element 33A. Additionally, in the display device of the comparative example, the luminance degradation of the virtual display region 2A progresses significantly faster during full-screen green display than during full-screen red display. This corresponds to the fact that, in the display device of the comparative example, the luminance degradation of the green light-emitting element 32A progresses significantly faster over time than the luminance degradation of the red light-emitting element 33A. This is because the effect of an increase in current density on luminance degradation over time increases as the wavelength of the emitted color of the light-emitting element becomes shorter. Furthermore, differences in the characteristics of the light-emitting material of the light-emitting layer of the light-emitting element, in other words, differences in the light-emitting material depending on the emitted color, also affect the change in the rate of luminance degradation over time in response to an increase in current density.

[0059] Therefore, the change over time of Δu'v' in the virtual display region 2A is larger than the change over time of Δu'v' in the first display region 1 of the display device in Example 1. For example, after 5000 hours of lighting time, Δu'v' in the virtual display region 2A differs from Δu'v' in the first display region 1 by 0.03 or more. This is because the deterioration over time of the luminance of the blue light-emitting element 31A progresses much faster than the deterioration over time of the luminance of the green light-emitting element 32A and the red light-emitting element 33A, resulting in a large change in chromaticity in the virtual display region 2A.

[0060] 8 , for the same reason as described above, the luminance degradation of the second display region 2 of the display device according to Example 1 is faster than the luminance degradation of the first display region 1 of the display device according to Example 1. This corresponds to the fact that the luminance degradation over time of each light-emitting element in the second display region 2 progresses faster than the luminance degradation over time of each light-emitting element in the first display region 1 of the display device according to Example 1. Furthermore, in the display device according to Example 1, the luminance degradation over time of the second display region 2 is faster during full-screen blue display than during full-screen green display, and is faster during full-screen green display than during full-screen red display. This corresponds to the fact that, in the display device according to Example 1, the luminance degradation over time of the blue light-emitting element 31 is faster than the luminance degradation of the green light-emitting element 32, and the luminance degradation of the green light-emitting element 32 is faster than the luminance degradation of the red light-emitting element 33.

[0061] On the other hand, in the second display region 2 of the display device according to Example 1, the difference in the rate of luminance degradation between the full-screen blue display and the full-screen green display is smaller than the difference in the rate of luminance degradation between the full-screen blue display and the full-screen green display in the virtual display region 2A of the display region according to the comparative example. This corresponds to the difference between the rate of luminance degradation over time of the green light-emitting element 32 and the red light-emitting element 33 and the rate of luminance degradation of the blue light-emitting element 31 in the second display region 2 of the display device according to Example 1 being smaller than that in the comparative example. Furthermore, in the second display region 2 of the display device according to Example 1, the difference in the rate of luminance degradation between the full-screen green display and the full-screen red display is smaller than the difference in the rate of luminance degradation between the full-screen green display and the full-screen red display in the virtual display region 2A of the display region according to the comparative example. This corresponds to the difference between the rate of luminance degradation over time of the red light-emitting element 33 and the rate of luminance degradation of the green light-emitting element 32 in the second display region 2 of the display device according to Example 1 being smaller than that in the comparative example.

[0062] The area ratio of the blue light-emitting region 41 to the blue light-emitting region 21 is greater than the area ratio of the green light-emitting region 42 to the green light-emitting region 22 and the area ratio of the red light-emitting region 43 to the red light-emitting region 23. Therefore, the increase in current density in the blue light-emitting element 31 relative to the blue light-emitting element 11 is smaller than the increase in current density in the green light-emitting element 32 relative to the green light-emitting element 12 and the increase in current density in the red light-emitting element 33 relative to the red light-emitting element 13. Therefore, in the second display region 2 of the display device according to Example 1, deterioration over time of the luminance of the blue light-emitting element 31 is reduced compared to deterioration over time of the luminance of the green light-emitting element 32 and the red light-emitting element 33.

[0063] Furthermore, the area ratio of the green light-emitting region 42 to the green light-emitting region 22 is greater than the area ratio of the red light-emitting region 43 to the red light-emitting region 23. Therefore, the increase in current density in the green light-emitting element 32 relative to the green light-emitting element 12 is smaller than the increase in current density in the red light-emitting element 33 relative to the red light-emitting element 13. Therefore, in the second display region 2 of the display device according to Example 1, the deterioration over time of the luminance of the green light-emitting element 32 is reduced relative to the deterioration over time of the luminance of the red light-emitting element 33.

[0064] As a result, the change in Δu'v' over time in the second display region 2 of the display device according to Example 1 is smaller than that in the virtual display region 2A of the display device according to the modification. In particular, the difference in the change in Δu'v' over time in the second display region 2 relative to the change in Δu'v' over time in the first display region 1 is smaller than that in the virtual display region 2A. In other words, the reduction ratio of the area of ​​each light-emitting region in the second display region 2 relative to the area of ​​each light-emitting region in the first display region 1 in a planar view of the display unit DA is determined so as to reduce the difference in Δu'v' between the first display region 1 and the second display region 2. Therefore, the display device according to Example 1 reduces the difference in the change in chromaticity over time between the first display region 1 and the second display region 2, thereby improving display quality.

[0065] Furthermore, in the second display region 2 of the display device according to Example 1, the luminance of the blue light-emitting element 31 deteriorates over time faster than the luminance of the green light-emitting element 32, which in turn deteriorates over time faster than the luminance of the red light-emitting element 33. In other words, the magnitude relationship of the rate of deterioration of luminance over time depending on the emission color of the light-emitting elements is the same between the first display region 1 and the second display region 2 of Example 1. Therefore, the display device according to Example 1 further reduces the difference in color between the first display region 1 and the second display region 2, thereby improving display quality.

[0066] In the display device according to Example 1, when the lighting time from the time of shipment reaches 1000 hours or more, the difference in Δu'v', in other words the color difference, is 0.01 or less between the first display region 1 and the second display region 2. As a result, the display device according to Example 1 further reduces the difference in color between the first display region 1 and the second display region 2, thereby improving the display quality.

[0067] Generally, when the areas of the light-emitting regions in a plan view are the same, the luminance of blue light-emitting elements deteriorates faster over time than that of green light-emitting elements and red light-emitting elements. Therefore, in order to reduce the change in chromaticity over time in display unit DA, it is considered to reduce the change in luminance over time, particularly of blue light-emitting elements 11 and 31. From the viewpoint of achieving both the expansion of light-transmitting region 3 in second display region 2 and the reduction in the deterioration in luminance of blue light-emitting element 31 over time, the area of ​​blue light-emitting region 41 may be 0.6 times or more but less than 1 time the area of ​​blue light-emitting region 21.

[0068] [Embodiment 2] <Modification of Deterioration Rate of Light-Emitting Element> The following describes a display device 100 according to embodiment 2. The display device 100 according to this embodiment has the same configuration as the display device 100 according to the previous embodiment, except for the rate of deterioration of the luminance of green light-emitting element 12 and green light-emitting element 32 over time, and the area ratio of green light-emitting region 42 to green light-emitting region 22.

[0069] In this embodiment, the rate of deterioration over time of the luminance of the green light emitting element 12 and the green light emitting element 32 is higher than in the previous embodiment. For example, the green light emitting element 12 and the green light emitting element 32 according to this embodiment may be made of different materials, such as functional layers including a light emitting layer, than the green light emitting element 12 and the green light emitting element 32 according to the previous embodiment.

[0070] 9 is an enlarged plan view showing the second display region 2 of the display unit DA of the display device 100 according to this embodiment. The area ratio of the green light-emitting region 42 to the green light-emitting region 22 according to this embodiment is larger than the area ratio of the green light-emitting region 42 to the green light-emitting region 22 according to the previous embodiment. Note that the area ratio of the red light-emitting region 43 to the red light-emitting region 23 according to this embodiment may be larger than the area ratio of the red light-emitting region 43 to the red light-emitting region 23 according to the previous embodiment.

[0071] For example, the area of ​​the green light-emitting region 42 may be 0.55 times the area of ​​the green light-emitting region 22. The area of ​​the red light-emitting region 43 may be 0.26 times the area of ​​the red light-emitting region 23.

[0072] A display device according to Example 2 having the same configuration as the display device 100 according to the present embodiment was manufactured, and its optical characteristics were measured. The results are summarized in Fig. 10 and Fig. 11. Fig. 10 is a graph showing the deterioration over time of luminance and the change over time Δu'v' in chromaticity in the first display region 1 of the display device according to Example 2. Fig. 11 is a graph showing the deterioration over time of luminance and the change over time Δu'v' in chromaticity in the second display region 2 of the display device according to Example 2.

[0073] As shown in FIG. 10 , in the display device according to Example 2, the luminance of each display region deteriorates more rapidly during full-screen green display compared to the display device according to Example 1. This corresponds to the luminance of the green light-emitting element 12 deteriorating over time more quickly. Accordingly, in Example 2, the change in Δu′v′ over time in the first display region 1 of the display device increases compared to Example 1. However, also in Example 2, the luminance of the first display region 1 deteriorates more rapidly during full-screen blue display than during full-screen green display. This corresponds to the luminance of the blue light-emitting element 11 deteriorating over time more quickly than the luminance of the green light-emitting element 12 in the display device according to Example 2.

[0074] 11 , in Example 2, the change over time of Δu′v′ in the second display region 2 of the display device increases in accordance with the increase in the change over time of Δu′v′ in the first display region 1, compared to Example 1. Therefore, the display device according to Example 2 reduces the difference in the change over time of chromaticity between the first display region 1 and the second display region 2, thereby improving display quality.

[0075] Third Embodiment <Modification of the Relationship Between Emitted Color and Rate of Luminance Deterioration Over Time> A display device 100 according to the third embodiment will be described below. In this embodiment, the rate of luminance deterioration over time of the green light-emitting elements 12 is slower than the rate of luminance deterioration over time of the red light-emitting elements 13, and the rate of luminance deterioration over time of the green light-emitting elements 32 is slower than the rate of luminance deterioration over time of the red light-emitting elements 33. Furthermore, the display device 100 according to this embodiment differs from the display device 100 according to the previous embodiments in the area ratio of the green light-emitting region 42 to the green light-emitting region 22 and the area ratio of the red light-emitting region 43 to the red light-emitting region 23. Except for the above, the display device 100 according to this embodiment has the same configuration as the display device 100 according to the previous embodiments.

[0076] 12 is an enlarged plan view showing the second display region 2 of the display unit DA of the display device 100 according to this embodiment. In this embodiment, the area ratio of the green light-emitting region 42 to the green light-emitting region 22 is smaller than the area ratio of the red light-emitting region 43 to the red light-emitting region 23. For example, the area of ​​the green light-emitting region 42 may be 0.24 times the area of ​​the green light-emitting region 22. Furthermore, the area of ​​the red light-emitting region 43 may be 0.4 times the area of ​​the red light-emitting region 23.

[0077] A display device according to Example 3 having the same configuration as the display device 100 according to the present embodiment was manufactured, and its optical characteristics were measured. The results are summarized in Fig. 13 and Fig. 14. Fig. 13 is a graph showing the deterioration over time of luminance and the change over time Δu'v' of chromaticity in the first display region 1 of the display device according to Example 3. Fig. 14 is a graph showing the deterioration over time of luminance and the change over time Δu'v' of chromaticity in the second display region 2 of the display device according to Example 3.

[0078] As shown in FIG. 13 , the luminance degradation of the first display region 1 according to Example 3 is slower during full-screen green display than during full-screen red display. This corresponds to the fact that the rate of luminance degradation over time of the green light-emitting element 12 is slower than the rate of luminance degradation over time of the red light-emitting element 13 in Example 3. Also, as shown in FIG. 14 , the luminance degradation of the second display region 2 according to Example 3 is slower during full-screen green display than during full-screen red display. This corresponds to the fact that the rate of luminance degradation over time of the green light-emitting element 32 is slower than the rate of luminance degradation over time of the red light-emitting element 33 in Example 3. Therefore, in Example 3 as well, the magnitude relationship between the rate of luminance degradation over time due to the emission color of the light-emitting element is the same between the first display region 1 and the second display region 2. Therefore, the display device according to Example 3 reduces the difference in chromaticity change over time between the first display region 1 and the second display region 2, thereby improving display quality.

[0079] [Embodiment 4] <Enlargement of Light-Emitting Area> A display device 100 according to embodiment 3 will be described below. Fig. 15 is an enlarged plan view showing the first display area 1 of the display unit DA of the display device 100 according to this embodiment. Fig. 16 is an enlarged plan view showing the second display area 2 of the display unit DA of the display device 100 according to this embodiment.

[0080] The blue light-emitting region 21 according to this embodiment has an area 1.5 times larger than that of the blue light-emitting region 21 according to the aforementioned embodiments. Accordingly, the blue light-emitting region 41 according to this embodiment has an area 1.5 times larger than that of the blue light-emitting region 41 according to the aforementioned embodiments. The green light-emitting region 22 and the red light-emitting region 23 according to this embodiment may each have the same area as that of the green light-emitting region 22 and the red light-emitting region 23 according to the aforementioned embodiments.

[0081] Furthermore, the display device 100 according to this embodiment differs from the display device 100 according to the above-described embodiments in the area ratios of the green light-emitting region 42 and the red light-emitting region 43 to the green light-emitting region 22 and the red light-emitting region 23, respectively. For example, the area of ​​the green light-emitting region 42 may be 0.6 times the area of ​​the green light-emitting region 22. The area of ​​the red light-emitting region 43 may be 0.38 times the area of ​​the red light-emitting region 23. The area of ​​the blue light-emitting region 41 may be 0.6 times the area of ​​the blue light-emitting region 21.

[0082] A display device according to Example 4 having the same configuration as the display device 100 according to the present embodiment was manufactured, and its optical characteristics were measured. The results are summarized in Fig. 17 and Fig. 18. Fig. 17 is a graph showing the deterioration over time of luminance and the change over time Δu'v' of chromaticity in the first display region 1 of the display device according to Example 4. Fig. 18 is a graph showing the deterioration over time of luminance and the change over time Δu'v' of chromaticity in the second display region 2 of the display device according to Example 4.

[0083] As shown in FIG. 17 , the display device according to Example 4 exhibits faster luminance degradation in the first display region 1 during full-screen blue display compared to the display devices according to the aforementioned examples. This corresponds to the fact that the rate of luminance degradation over time of the blue light-emitting element 11 according to Example 4 is slower than the rate of luminance degradation over time of the blue light-emitting element 11 according to the aforementioned examples. Furthermore, as shown in FIG. 18 , the display device according to Example 4 exhibits faster luminance degradation in the second display region 2 during full-screen blue display compared to the display devices according to the aforementioned examples. This corresponds to the fact that the rate of luminance degradation over time of the blue light-emitting element 31 according to Example 4 is slower than the rate of luminance degradation over time of the blue light-emitting element 31 according to the aforementioned embodiments. This is because the current density of the blue light-emitting element 11 and the blue light-emitting element 31 is reduced due to the increased areas of the blue light-emitting region 21 and the blue light-emitting region 41 in Example 4.

[0084] 18 , the luminance degradation of the second display region 2 of the display device according to Example 4 is faster during full green display and full red display than that of the second display region 2 of the display devices according to the above-described examples. This corresponds to the rate of luminance degradation over time of the green light-emitting element 32 and the red light-emitting element 33 according to Example 4 being slower than that of the green light-emitting element 32 and the red light-emitting element 33 according to the above-described examples. Therefore, the display device according to Example 4 reduces the difference in chromaticity change over time between the first display region 1 and the second display region 2, thereby improving display quality.

[0085] In particular, in Example 4, the blue light-emitting region 21 of the blue light-emitting element 11, which has the fastest rate of deterioration in luminance over time among the light-emitting elements in the first display region 1, is enlarged compared to the previous Examples. Therefore, the display device according to Example 4 reduces the change in Δu'v' over time and improves the display quality, as shown in Figures 17 and 18.

[0086] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0087] 100 Display device DA Display unit 1 First display area (normal display area) 2 Second display area (light-reflecting display area) 2A Virtual display area 11 Blue light-emitting element (first light-emitting element) 12 Green light-emitting element (second light-emitting element) 13 Red light-emitting element (fifth light-emitting element) 21 Blue light-emitting area (first light-emitting area) 22 Green light-emitting area (second light-emitting area) 23 Red light-emitting area (fifth light-emitting area) 31 Blue light-emitting element (third light-emitting element) 32 Green light-emitting element (fourth light-emitting element) 33 Red light-emitting element (sixth light-emitting element) 41 Blue light-emitting area (third light-emitting area) 42 Green light-emitting area (fourth light-emitting area) 43 Red light-emitting area (sixth light-emitting area) CU Camera unit

Claims

1. A display device including a display unit with a first display region and a second display region, each having a plurality of light-emitting regions, wherein, in a planar view, the occupancy rate of the light-emitting regions included in the second display region in the display unit is smaller than the occupancy rate of the light-emitting regions included in the first display region, and the second display region has a smaller difference in the change in chromaticity over time of light obtained when all of the light-emitting regions are emitting light, compared to a virtual display region obtained by reducing the area of ​​each light-emitting region of the first display region at the same area ratio in a planar view.

2. A display device including a display section having a first display area and a second display area each having a plurality of light-emitting areas, wherein, in a planar view, the occupancy rate of the light-emitting areas included in the second display area in the display section is smaller than the occupancy rate of the light-emitting areas included in the first display area, and a reduction ratio of the area of ​​each light-emitting area of ​​the second display area relative to the area of ​​each light-emitting area of ​​the first display area in a planar view is determined so that the difference in the change over time in chromaticity of light obtained when all of the light-emitting areas emit light between the first display area and the second display area is small.

3. A display device as described in claim 1 or 2, wherein the first display region has a first light-emitting region that emits light including a first wavelength and a second light-emitting region that emits light including a second wavelength longer than the first wavelength, and the second display region has a third light-emitting region that emits light including the first wavelength and a fourth light-emitting region that emits light including the second wavelength.

4. The display device according to claim 3, wherein the first light-emitting region exhibits faster deterioration in luminance over time than the second light-emitting region, and the third light-emitting region exhibits faster deterioration in luminance over time than the fourth light-emitting region.

5. The display device according to claim 4, wherein, in a plan view, an area ratio of the third light-emitting region to the first light-emitting region is greater than an area ratio of the fourth light-emitting region to the second light-emitting region.

6. A display device according to any one of claims 3 to 5, wherein, in a plan view, an area of ​​the third light-emitting region is smaller than an area of ​​the first light-emitting region, and an area of ​​the fourth light-emitting region is smaller than an area of ​​the second light-emitting region.

7. The display device according to any one of claims 3 to 6, wherein the light of the first wavelength is blue light, and the light of the second wavelength is green light.

8. The display device according to claim 7, wherein the display section includes blue light-emitting elements in each of the first light-emitting region and the third light-emitting region, and green light-emitting elements in each of the second light-emitting region and the fourth light-emitting region.

9. A display device described in any one of claims 3 to 8, wherein the first display region has a fifth light-emitting region that emits light including a third wavelength that is longer than the second wavelength, and the second display region has a sixth light-emitting region that emits light including the third wavelength.

10. The display device according to claim 9, wherein the first light-emitting region exhibits faster deterioration in luminance over time than the fifth light-emitting region, and the third light-emitting region exhibits faster deterioration in luminance over time than the sixth light-emitting region.

11. The display device according to claim 10, wherein, in a plan view, an area ratio of the third light-emitting region to the first light-emitting region is greater than an area ratio of the sixth light-emitting region to the fifth light-emitting region.

12. A display device described in any one of claims 9 to 11, wherein the second light-emitting region has a faster deterioration in luminance over time than the fifth light-emitting region, and the fourth light-emitting region has a faster deterioration in luminance over time than the sixth light-emitting region.

13. The display device according to claim 12, wherein, in a plan view, an area ratio of the fourth light-emitting region to the second light-emitting region is greater than an area ratio of the sixth light-emitting region to the fifth light-emitting region.

14. A display device according to any one of claims 9 to 11, wherein the fifth light-emitting region is subject to faster deterioration in luminance over time than the second light-emitting region, and the sixth light-emitting region is subject to faster deterioration in luminance over time than the fourth light-emitting region.

15. The display device according to claim 14, wherein, in a plan view, an area ratio of the sixth light-emitting region to the fifth light-emitting region is greater than an area ratio of the fourth light-emitting region to the second light-emitting region.

16. The display device according to any one of claims 9 to 15, wherein, in a plan view, the area of ​​the sixth light-emitting region is smaller than the area of ​​the fifth light-emitting region.

17. The display device according to any one of claims 9 to 16, wherein the light of the third wavelength is red light.

18. The display device according to claim 17, wherein the display section includes a red light emitting element in each of the fifth light emitting region and the sixth light emitting region.

19. A display device according to any one of claims 3 to 18, wherein, in a plan view, the area of ​​the third light-emitting region is 0.6 times or more the area of ​​the first light-emitting region.

20. A display device described in any one of claims 1 to 19, wherein the color difference of the light obtained when all of the light-emitting areas are made to emit light between the first display area and the second display area after all of the light-emitting areas have been made to emit light for more than 1,000 hours from the time of shipment is 0.01 or less.

21. A display device according to any one of claims 1 to 20, wherein the first display area is a normal display area, and the second display area is a daylighting display area that takes in external light from between the light-emitting areas.

22. The display device according to claim 21, comprising: a display panel including the display portion; and a camera unit located on the opposite side to the display surface of the display panel and overlapping with the light-gathering display area in a plan view.

Images