Display device

Abstract

To provide a display device capable of improving light extraction efficiency.SOLUTION: A display device includes an insulating substrate, an organic electroluminescent element existing on the insulating substrate and including an anode electrode and an organic light-emitting layer, a rib existing on the insulating substrate and having an anode opening at a position overlapping the anode electrode, a sealing layer that seals the organic electroluminescent element and the rib between the sealing layer and the insulating substrate, a first lens existing on the sealing layer, and an overcoat layer covering the first lens. The first lens overlaps over the anode opening, an edge of the anode opening, and the rib.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] Embodiments of the present invention relate to a display device.

Background Art

[0002] In recent years, an organic electroluminescence (EL) display device using an organic light-emitting diode (OLED) as a display element has been put into practical use. This display element includes an anode electrode, a cathode electrode facing the anode electrode, and an organic light-emitting layer positioned between the anode electrode and the cathode electrode.

[0003] In an organic EL display device as described above, a technique for efficiently extracting the light generated in the organic light-emitting layer to the outside is required. As an example, a technique combining a microlens array including a plurality of microlenses is known in order to improve the luminance of the organic EL display device.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present embodiment is to provide a display device capable of improving light extraction efficiency.

Means for Solving the Problems

[0006] According to the present embodiment, there is provided a display device including an insulating substrate, an organic electroluminescence element located on the insulating substrate and including an anode electrode and an organic light-emitting layer, a rib located on the insulating substrate and having an anode opening at a position overlapping with the anode electrode, a sealing layer for sealing the organic electroluminescence element and the rib between the insulating substrate, a first lens located on the sealing layer, and an overcoat layer covering the first lens, wherein the first lens overlaps across the anode opening, an edge of the anode opening, and the rib.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Embodiments for Carrying Out the Invention

[0008] Hereinafter, this embodiment will be described with reference to the drawings. Note that the disclosure is merely an example, and for those that can be easily conceived by those skilled in the art for appropriate modifications while maintaining the gist of the invention, they are naturally included in the scope of the present invention. Also, for the sake of clearer explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual aspect, but this is merely an example and does not limit the interpretation of the present invention. Further, in this specification and each figure, components that exhibit the same or similar functions as those described above with respect to the previously shown figures are given the same reference numerals, and detailed descriptions that are redundant may be omitted as appropriate.

[0009] [First Embodiment] First, with reference to FIGS. 1 to 4, the configuration of this embodiment will be described.

[0010] FIG. 1 is a plan view schematically showing a display device DSP according to this embodiment. The display device DSP of this embodiment is an organic electroluminescence (EL) display device.

[0011] In one example, the first direction X, the second direction Y, and the third direction Z are orthogonal to each other, but they may intersect at an angle other than 90 degrees. The first direction X and the second direction Y correspond to directions parallel to the main surface of the substrate constituting the display device DSP, and the third direction Z corresponds to the thickness direction of the display device DSP. In this specification, the direction toward the tip of the arrow indicating the third direction Z is defined as up, and the direction opposite to the tip of the arrow is defined as down. Also, it is assumed that there is an observation position for observing the display device DSP on the tip side of the arrow indicating the third direction Z, and looking from this observation position toward the X - Y plane defined by the first direction X and the second direction Y is referred to as a plan view.

[0012] The display device DSP includes a display panel PNL and a wiring board 1 mounted on the display panel PNL.

[0013] The display panel PNL is an organic EL display panel, and includes a first substrate SUB1 and a second substrate SUB2 facing the first substrate SUB1. The first substrate SUB1 has a mounting portion MT exposed outside the second substrate SUB2. The display panel PNL includes a display area DA for displaying an image and a non-display area NDA surrounding the display area DA. The display panel PNL includes a plurality of pixels PX arranged in a matrix in a first direction X and a second direction Y in the display area DA.

[0014] The pixel PX is composed of a sub-pixel SPX1 for displaying green (G), a sub-pixel SPX2 for displaying red (R), and a sub-pixel SPX3 for displaying blue (B). Inside the pixel PX, the sub-pixel SPX3 extends in the second direction Y. The sub-pixel SPX1 is arranged in the first direction X of the sub-pixel SPX3. The sub-pixel SPX2 is arranged in the first direction X of the sub-pixel SPX3 and in the second direction Y of the sub-pixel SPX1.

[0015] Note that the size, arrangement, and color of each sub-pixel are not limited to the illustrated example. Also, in the illustrated example, pixels PX having the same sub-pixel pattern are arranged in a matrix, but this is not limiting, and in each pixel PX, the size, arrangement, and color of each sub-pixel may be different from each other.

[0016] The wiring board 1 is a flexible board and is mounted on the mounting portion MT. The display panel PNL and the wiring board 1 are electrically connected to each other. Also, the wiring board 1 includes a driving IC chip 2 for driving the display panel PNL. Note that the driving IC chip 2 may be mounted on the mounting portion MT.

[0017] FIG. 2 is a plan view showing one pixel PX of the display panel PNL shown in FIG. 1. The display panel PNL includes anode electrodes AN1, AN2, AN3, ribs RB, a light-shielding layer BM, and a plurality of lenses LS.

[0018] The anode electrodes AN1, AN2, AN3 are respectively arranged in the sub-pixels SPX1, SPX2, SPX3.

[0019] The rib RB has an anode opening AP1 that defines the sub-pixel SPX1, an anode opening AP2 that defines the sub-pixel SPX2, and an anode opening AP3 that defines the sub-pixel SPX3. The arrangement of the anode openings AP1 to AP3 is the same as the arrangement of the sub-pixels SPX1 to SPX3. The anode openings AP1 to AP3 are formed in a rectangular shape. The anode opening AP1 is formed at a position overlapping the anode electrode AN1. The anode opening AP2 is formed at a position overlapping the anode electrode AN2. The anode opening AP3 is formed at a position overlapping the anode electrode AN3.

[0020] The anode opening AP1 has an edge EG1 that is the outer edge of the anode opening AP1. The edge EG1 has edges EG11 and EG12 extending in the first direction X and edges EG13 and EG14 extending in the second direction Y. Also, the anode opening AP2 has an edge EG2 that is the outer edge of the anode opening AP2. The anode opening AP3 has an edge EG3 that is the outer edge of the anode opening AP3.

[0021] The width W11 of the anode opening AP1 along the first direction X is about 20 μm. The width W12 of the anode opening AP1 along the second direction Y is about 20 μm. The width W21 of the anode opening AP2 along the first direction X is about 20 μm. The width W22 of the anode opening AP2 along the second direction Y is about 20 μm. The width W31 of the anode opening AP3 along the first direction X is about 20 μm. The width W32 of the anode opening AP3 along the second direction Y is about 60 μm.

[0022] The width W41 along the first direction X between the anode opening AP1 and the anode opening AP3 is about 20 μm. The width W42 along the first direction X between the anode opening AP2 and the anode opening AP3 is about 20 μm. The width W51 along the second direction Y between the anode opening AP1 and the anode opening AP2 is about 20 μm. The widths W41, W42, and W51 correspond to the width of the rib RB.

[0023] The light-shielding layer BM is disposed in the region indicated by hatching in the figure. The light-shielding layer BM overlaps with the rib RB in the entire region indicated by hatching in the figure. The light-shielding layer BM has openings OP1, OP2, and OP3. The opening OP1 is formed at a position overlapping with the anode opening AP1. The opening OP2 is formed at a position overlapping with the anode opening AP2. The opening OP3 is formed at a position overlapping with the anode opening AP3.

[0024] The width of the opening OP1 along the first direction X is larger than the width W11 of the anode opening AP1 along the first direction X. The width of the opening OP1 along the second direction Y is larger than the width W12 of the anode opening AP1 along the second direction Y. The width of the opening OP2 along the first direction X is larger than the width W21 of the anode opening AP2 along the first direction X. The width of the opening OP2 along the second direction Y is larger than the width W22 of the anode opening AP2 along the second direction Y. The width of the opening OP3 along the first direction X is larger than the width W31 of the anode opening AP3 along the first direction X. The width of the opening OP3 along the second direction Y is larger than the width W32 of the anode opening AP3 along the second direction Y.

[0025] The plurality of lenses LS are formed with equal sizes to each other and are formed in a circular shape in plan view. The diameter D of each lens LS is, for example, about 12 μm.

[0026] In the illustrated example, four lenses LS11, LS12, LS13, and LS14 are disposed with respect to the anode opening AP1. The lenses LS11, LS12, LS13, and LS14 are disposed at the four corners of the anode opening AP1. The lenses LS11, LS12, LS13, and LS14 respectively overlap across the anode opening AP1, the edge EG1, and the rib RB.

[0027] Specifically, lens LS11 overlaps across anode opening AP1, edges EG11 and EG13, and rib RB. Lens LS12 overlaps across anode opening AP1, edges EG11 and EG14, and rib RB. Lens LS13 overlaps across anode opening AP1, edges EG12 and EG13, and rib RB. Lens LS14 overlaps across anode opening AP1, edges EG12 and EG14, and rib RB.

[0028] That is, lens LS11 overlaps with the intersection of edges EG11 and EG13, lens LS12 overlaps with the intersection of edges EG11 and EG14, lens LS13 overlaps with the intersection of edges EG12 and EG13, and lens LS14 overlaps with the intersection of edges EG12 and EG14.

[0029] In the illustrated example, four lenses LS21, LS22, LS23, and LS24 are arranged with respect to anode opening AP2. Lenses LS21, LS22, LS23, and LS24 are arranged at the four corners of anode opening AP2. Lenses LS21, LS22, LS23, and LS24 each overlap across anode opening AP2, edge EG2, and rib RB.

[0030] In the illustrated example, six lenses LS31, LS32, LS33, LS34, LS35, and LS36 are arranged with respect to anode opening AP3. Lenses LS31, LS32, LS33, and LS34 are arranged at the four corners of anode opening AP3. Lenses LS35 and LS36 are arranged on the long side of edge EG3 of anode opening AP3. Lens LS35 is located between lens LS31 and lens LS33. Lens LS36 is located between lens LS32 and lens LS34. Lenses LS31, LS32, LS33, LS34, LS35, and LS36 each overlap across anode opening AP3, edge EG3, and rib RB. Note that in the illustrated example, a part of each lens LS overlaps with light-shielding layer BM.

[0031] As shown with reference to lens LS11, the center O of lens LS11 is located inside the edge EG1 of anode opening AP1. Similarly for the other lenses LS, the center O of each lens LS is located inside the edge EG1 of anode opening AP1, the edge EG2 of anode opening AP2, and the edge EG3 of anode opening AP3. The center O of lens LS11 is located inside by a length L1 with respect to edge EG13 in the first direction X. Also, the center O of lens LS11 is located inside by a length L2 with respect to edge EG11 in the second direction Y. The lengths L1 and L2 are, for example, about 3 μm.

[0032] Figure 3 is a cross-sectional view of display panel PNL along the line A-B shown in Figure 2. As shown in Figure 3, display panel PNL includes an insulating substrate 10, a circuit layer 11, an insulating film 12, an organic electroluminescence (EL) element OLED, a rib RB, a cap layer 13, a sealing layer 40, a light-shielding layer BM, a color filter layer CF, a lens LS, an overcoat layer OC, a sealing substrate 20, etc.

[0033] The insulating substrate 10 may be a glass substrate or a resin film having flexibility.

[0034] The circuit layer 11 is formed on the insulating substrate 10. The circuit layer 11 includes various circuits such as pixel circuits and various wirings such as scanning lines, signal lines, and power lines. The insulating film 12 covers the circuit layer 11. The insulating film 12 includes an organic insulating film that planarizes the unevenness caused by the circuit layer 11.

[0035] The organic EL element OLED is formed on the insulating film 12. That is, the organic EL element OLED is located on the insulating substrate 10. The organic EL element OLED is configured as a top emission type that emits light toward the side of the sealing substrate 20. One organic EL element is arranged in one sub-pixel, and the organic EL elements arranged in the sub-pixels SPX1, SPX2, and SPX3 all have the same structure. The organic EL element OLED is partitioned by the rib RB. The rib RB is located on the insulating substrate 10. Note that the anode opening AP1 is defined by the lower end of the rib RB.

[0036] The organic EL element OLED includes an anode electrode AN1. The anode electrode AN1 is electrically connected to a switching element (not shown). The anode electrode AN1 is formed of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example.

[0037] The organic EL element OLED arranged at a position overlapping the anode opening AP1 includes an organic light-emitting layer OR that emits green light. Similarly, the organic EL element arranged at a position overlapping the anode opening AP2 includes an organic light-emitting layer that emits red light. The organic EL element arranged at a position overlapping the anode opening AP3 includes an organic light-emitting layer that emits blue light. The organic light-emitting layer OR is located on the anode electrode AN1.

[0038] The organic EL element OLED includes a cathode electrode CT. The cathode electrode CT is located on the organic light-emitting layer OR and is also commonly located on the organic light-emitting layers arranged in other sub-pixels. The cathode electrode CT is also located on the rib RB. The cathode electrode CT is formed of, for example, an MgAg alloy.

[0039] The cap layer 13 is disposed on the cathode electrode CT. The cap layer 13 is a transparent multilayer body. The refractive indices of the respective layers constituting the cap layer 13 are different from each other. Such a cap layer 13 functions as an optical adjustment layer for adjusting the optical characteristics of the light emitted from the organic light-emitting layer OR.

[0040] The encapsulation layer 40 encapsulates the organic EL element OLED and the rib RB between the insulating substrate 10. Further, the encapsulation layer 40 similarly encapsulates other members disposed between the insulating substrate 10. The encapsulation layer 40 suppresses the intrusion of oxygen and moisture into the organic EL element OLED and suppresses the deterioration of the organic EL element OLED. The encapsulation layer 40 is composed of a laminate of an inorganic film 41, an organic film 42, and an inorganic film 43. The inorganic films 41 and 43 are formed using, for example, silicon nitride. The organic film 42 is formed using, for example, an organic material such as a resin.

[0041] The light-shielding layer BM is located on the encapsulation layer 40. Specifically, the light-shielding layer BM is located on the inorganic film 43 of the encapsulation layer 40. The width along the second direction Y of the opening OP1 is, for example, about 25 μm. As described above, the width along the second direction Y of the anode opening AP1 is about 20 μm. That is, the width of the opening OP1 is formed to be about 5 μm larger than the width of the anode opening AP1. For this reason, the light traveling in an oblique direction from the organic EL element OLED is not blocked by the light-shielding layer BM, and the visibility of the display from an oblique viewing angle can be maintained.

[0042] The color filter layer CF is located on the light-shielding layer BM and the encapsulation layer 40. The color filter layer CF has a first color filter CF1 of a first color, a second color filter CF2 of a second color different from the first color, and a third color filter of a third color different from the first color and the second color (not shown). The first color filter CF1 overlaps the anode opening AP1. The second color filter CF2 overlaps the anode opening AP2. The third color filter overlaps the anode opening AP3. The first color filter CF1 and the second color filter CF2 are adjacent to each other.

[0043] The first color filter CF1 is a green color filter. The second color filter CF2 is a red color filter. The third color filter is a blue color filter. The first color filter CF1 overlaps with an organic EL element OLED that emits green light. The second color filter CF2 overlaps with an organic EL element that emits red light. The third color filter overlaps with an organic EL element that emits blue light. Note that the colors of the first color filter CF1, the second color filter CF2, and the third color filter are not limited to the above examples and can be appropriately changed according to the emission color of the organic EL element.

[0044] The plurality of lenses LS are located on the color filter layer CF. That is, the plurality of lenses LS are located on the sealing layer 40. The lens LS is formed using, for example, an acrylic resin or an epoxy resin. The thickness T of the lens LS is, for example, about 2 μm. Each lens LS has an inclined portion SP between the center O of the lens LS and the outer edge LSE of the lens LS. A part of the inclined portion SP overlaps with the rib RB.

[0045] The overcoat layer OC covers the plurality of lenses LS and the color filter layer CF. The overcoat layer OC is formed of an organic material such as a transparent resin, and is formed using an acrylic resin or an epoxy resin. As will be described later with reference to FIG. 8, the overcoat layer OC may contain either metal nanoparticles or hollow particles.

[0046] The sealing substrate 20 is located on the overcoat layer OC. The sealing substrate 20 may be a glass substrate or a resin film having flexibility.

[0047] The thickness of the inorganic film 41 of the sealing layer 40 is, for example, about 1 μm. The thickness of the organic film 42 of the sealing layer 40 is, for example, about 10 μm. The thickness of the inorganic film 43 of the sealing layer 40 is, for example, about 1 μm. The thickness of the color filter layer CF is, for example, about 2 μm. The thickness of the overcoat layer OC is, for example, about 4 μm. Also, the thickness of the overcoat layer OC is formed to be about 1 μm or more greater than the thickness T of the lens LS. Since the thickness of the overcoat layer OC is 4 μm or less in a state not containing particles, at this time, it is desirable that the thickness T of the lens LS is 3 μm or less. The thickness of the sealing substrate 20 is, for example, about 0.5 mm.

[0048] In the above configuration example, the display panel PNL includes an organic light-emitting layer that emits green light, an organic light-emitting layer that emits red light, and an organic light-emitting layer that emits blue light, but is not limited thereto. Each organic EL element may include a common organic light-emitting layer. At this time, for example, the organic EL element emits white light. In the present embodiment, since the display panel PNL includes the color filter layer CF, color display of the display device DSP is realized even when the organic EL element emits white light.

[0049] Also, the display panel PNL of the present embodiment does not include a polarizing plate on the sealing substrate 20. Instead, the light-shielding layer BM and the color filter layer CF are disposed on the sealing layer 40. Therefore, external light reflection at the cathode electrode CT and the like can be suppressed by the color filter layer CF. Compared with the case of suppressing external light reflection using a polarizing plate, the transmittance of the light emitted from the organic EL element OLED can be improved. Therefore, a decrease in display luminance can be suppressed and power consumption can be reduced. Also, since the color filter layer CF is thinner than the polarizing plate, the display panel PNL can be thinned. Furthermore, the cost when using a polarizing plate can be reduced.

[0050] Figure 4 is a cross-sectional view showing the refraction of light in the lens LS. For example, assuming a case where the lens LS is not arranged as a comparative example, among the light incident obliquely from the organic EL element OLED on the interface between the sealing substrate 20 and air, the light incident at an angle equal to or greater than the critical angle is totally reflected, and thus cannot exit from the upper surface 20S of the sealing substrate 20.

[0051] According to the present embodiment, the lens LS is arranged straddling the edge EG1 of the anode opening AP1. Therefore, as shown in the figure, the light L1 emitted from the organic EL element OLED in the left diagonal direction is refracted toward the upper surface 20S at the inclined portion SP of the lens LS11, and the light L2 emitted from the organic EL element OLED in the right diagonal direction is refracted toward the upper surface 20S at the inclined portion SP of the lens LS13. That is, before the light is incident on the interface between the sealing substrate 20 and air, the incident angle of the light can be made smaller than the critical angle of total reflection by the lens LS. Thereby, the light that is totally reflected is reduced, and more light can be made to exit from the upper surface 20S of the sealing substrate 20. More specifically, the luminance of the area where the lens LS protrudes from the edge EG1 of the anode opening AP1 can be improved. Therefore, the light extraction efficiency of the display panel PNL can be improved.

[0052] Also, as described above, by not arranging the polarizing plate, the luminance of the display panel PNL can be improved. However, there is a concern that the external light reflection at the anode opening increases only with the color filter CF. From the viewpoint of external light reflection, it is desirable that the anode opening ratio is lower, that is, it is necessary to make the coverage rate of the light shielding layer BM equal to or higher than a certain level. Specifically, it is necessary to make the area of the light shielding layer BM 65% or more in one pixel. That is, the upper limit of the anode opening ratio is determined by the external light reflection characteristics, and it has been difficult to improve the luminance. In the configuration of the present embodiment, even in a display device in which the polarizing plate is not arranged, the luminance of the display panel PNL can be improved without increasing the anode opening ratio, that is, without increasing the external light reflection.

[0053] Next, the refractive indices of the respective members constituting the display panel PNL will be described. The refractive indices of the inorganic films 41 and 43 of the sealing layer 40 are, for example, 1.8. The refractive index of the organic film 42 of the sealing layer 40 is, for example, 1.6. The refractive index of the color filter layer CF is, for example, 1.6. The refractive index of the lens LS is, for example, 1.5 to 1.7. The refractive index of the overcoat layer OC is, for example, 1.0 to 1.5. Here, when the refractive index of the overcoat layer OC is 1.0, it is assumed that hollow particles are mixed in the overcoat layer OC.

[0054] In order to refract light at the interface between the lens LS and the overcoat layer OC, the refractive index of the overcoat layer OC is set lower than the refractive index of the lens LS. In order to refract light more at the interface between the lens LS and the overcoat layer OC, the difference between the refractive index of the lens LS and the refractive index of the overcoat layer OC is desirably about 0.3.

[0055] Next, the design conditions will be described. Let the anode opening width or anode opening diameter be L (μm). The anode opening width corresponds to the width of the anode opening along the first direction X and the width of the anode opening along the second direction Y when the anode opening is rectangular. The anode opening diameter corresponds to the diameter of the anode opening when the anode opening is circular, as shown in FIG. 9.

[0056] As shown in FIG. 4, the width from the edge EG1 of the anode opening AP1 to the end BE of the opening OP1 of the light shielding layer BM is defined as the one-sided width BW of the opening OP1. The one-sided width BW does not depend on L (μm) and is 2.5 to 6 μm. This numerical value of the one-sided width BW is a numerical value for preventing light traveling obliquely from the organic EL element OLED from being blocked by the light shielding layer BM.

[0057] The diameter of the lens LS is L / 2 ± 0.3L (μm).

[0058] The center O of the lens LS is arranged inside by L / 4 ± 0.3L (μm) from the edge EG1 of the anode opening AP1.

[0059] The thickness T of the lens LS is preferably L / 10 to L / 3 (μm).

[0060] In practice, there are manufacturing upper limits for the diameter and thickness of the lens LS. The diameter of the lens LS depends on the anode opening width L. That is, a lens LS size greater than a certain value is required relative to the size of the anode opening. In other words, due to the existence of upper limits for the diameter and thickness of the lens LS, there is also an upper limit for the anode opening width L at which the effects of this embodiment can be obtained. The anode opening width L at which the effects of this embodiment can be obtained is 110 μm or less.

[0061] The lenses LS11 and LS13 overlap with the first color filter CF1 and do not overlap with the second color filter CF2. That is, each lens LS overlaps with one color filter and does not overlap with two or more color filters. Thereby, before light reaches the lens LS from the organic EL element OLED, absorption of light by a color filter of a color different from that of adjacent emitted light can be suppressed, and a decrease in the light utilization efficiency can be suppressed.

[0062] Next, with reference to FIGS. 5 to 7, the results of the optical simulation will be described.

[0063] FIG. 5 is a diagram showing the results of an optical simulation when the arrangement and diameter of the lens LS with respect to the anode opening AP are changed. The refractive index of the lens LS shown in FIG. 5 is 1.73, and at this time, the refractive index of the overcoat layer OC is 1.46. The difference between the refractive index of the lens LS and the refractive index of the overcoat layer OC is 0.27.

[0064] FIG. 5(a) shows the anode opening AP where the lens LS is not arranged. FIG. 5(a) is a reference for this optical simulation. The vertical width of the anode opening AP is 20 μm, and the horizontal width is 20 μm.

[0065] Fig. 5(b) shows an example in which nine lenses LS with a diameter of 3 μm are arranged with respect to the anode opening AP. The lenses LS are arranged at the four corners of the anode opening AP, at the center of each side of the edge EG, and at the center of the anode opening AP.

[0066] Fig. 5(c) shows an example in which nine lenses LS with a diameter of 6 μm are arranged with respect to the anode opening AP. The lenses LS are arranged at the four corners of the anode opening AP, at the center of each side of the edge EG, and at the center of the anode opening AP.

[0067] Fig. 5(d) shows an example in which four lenses LS with a diameter of 9 μm are arranged with respect to the anode opening AP. The lenses LS are arranged at the four corners of the anode opening AP.

[0068] Fig. 5(e) shows an example in which four lenses LS with a diameter of 12 μm are arranged with respect to the anode opening AP. The lenses LS are arranged at the four corners of the anode opening AP.

[0069] Fig. 5(f) is a graph showing the relationship between the viewing angle and the luminance ratio for each of Figs. 5(a) to 5(e). The horizontal axis A represents the viewing angle (°), and the vertical axis B represents the luminance ratio. In the graph, the lines indicating the results of Figs. 5(a) to 5(e) are referred to as lines (a) to (e).

[0070] When the viewing angle is 0° of line (a) in the state where the lens LS is not arranged, the luminance ratio is set to 1. Here, the viewing angle of 0° corresponds to an angle perpendicular to the display surface of the display device. Also, the luminance obtained at a viewing angle of 0° corresponds to the front luminance of the display device.

[0071] No significant change was observed for lines (b) to (d) compared to the reference. On the other hand, line (e) shows a significant increase in luminance at a viewing angle of 0° compared to lines (a) to (d). That is, the greatest luminance increase effect was obtained when the diameter of the lens LS was 12 μm with respect to the width of the anode opening AP of 20 μm. At this time, the ratio of the diameter of the lens LS to the width of the anode opening AP is 12 / 20 = 0.6.

[0072] Under the conditions of Fig. 5(e), an increase in front luminance of 30% could be obtained. Summing up the area of the lens LS protruding from the anode aperture AP, it was about 30% of the area of the anode aperture AP, and the result was obtained that the portion of the lens LS protruding from the anode aperture AP contributed to the increase in luminance.

[0073] From the optical simulation shown in Fig. 5, the conclusion was obtained that in order to improve the front luminance, the diameter of the lens LS needs to be a certain value or more with respect to the width of the anode aperture AP.

[0074] Fig. 6 is a graph showing the relationship between the viewing angle and the luminance ratio when the thickness of the lens LS is changed. The horizontal axis A indicates the viewing angle (°), and the vertical axis B indicates the luminance ratio. In the graph, the lines showing the respective results for lens LS thicknesses of 0μm, 1μm, 2μm, 3μm, 5μm, and 6μm are defined as line (g), line (h), line (i), line (j), line (k), and line (l).

[0075] In the optical simulation shown in Fig. 6, the conditions of the anode aperture AP and the lens LS are fixed to the conditions shown in Fig. 5(e). That is, Fig. 6 shows the results of the optical simulation when the vertical width of the anode aperture AP is 20μm, the horizontal width is 20μm, the diameter of the lens LS is 12μm, and four lenses LS are arranged at the four corners of the anode aperture AP. The refractive index of the lens LS is 1.73, and at this time the refractive index of the overcoat layer OC is 1.46. The difference between the refractive index of the lens LS and the refractive index of the overcoat layer OC is 0.27.

[0076] Line (g) shows the result when the thickness of the lens LS is 0μm, that is, when the lens LS is not arranged. Line (g) is the reference for this optical simulation.

[0077] When the viewing angle of the (g) line is 0° in the state where the lens LS is not arranged, the luminance ratio is set to 1. The (i) line and the (j) line have a significantly increased luminance at a viewing angle of 0° compared to the (h) line, the (k) line, and the (l) line. That is, the most significant luminance increase effect was obtained when the thickness of the lens LS was 2 μm and 3 μm.

[0078] From the optical simulation shown in FIG. 6, it was concluded that when the thickness of the lens LS is less than a certain value or greater than a certain value, the luminance ratio decreases from the optimum value.

[0079] FIG. 7 is a graph showing the relationship between the viewing angle and the luminance ratio when the refractive index of the lens LS is decreased by 0.1 and the thickness of the lens LS is changed. The horizontal axis A represents the viewing angle (°), and the vertical axis B represents the luminance ratio. In the graph, the lines showing the results for lens LS thicknesses of 0 μm, 1 μm, 2 μm, 3 μm, 5 μm, and 6 μm are designated as the (m) line, the (n) line, the (o) line, the (p) line, the (q) line, and the (r) line, respectively.

[0080] In the optical simulation shown in FIG. 7, the conditions of the anode aperture AP and the lens LS are fixed to the conditions shown in FIG. 5(e). That is, FIG. 7 shows the results of an optical simulation when the vertical width of the anode aperture AP is 20 μm, the horizontal width is 20 μm, the diameter of the lens LS is 12 μm, and four lens LSs are arranged at the four corners of the anode aperture AP.

[0081] In the optical simulations shown in FIGS. 5 and 6, the refractive index of the lens LS was 1.73, the refractive index of the overcoat layer OC was 1.46, and the difference between the refractive index of the lens LS and the refractive index of the overcoat layer OC was 0.27. In the optical simulation shown in FIG. 7, since the refractive index of the lens LS was decreased by 0.1, the refractive index of the lens LS is 1.63, and the difference between the refractive index of the lens LS and the refractive index of the overcoat layer OC is 0.17.

[0082] (m) line shows the results when the thickness of lens LS is 0 μm, that is, when lens LS is not arranged. (m) line is the reference of this optical simulation.

[0083] When the viewing angle of (m) line is 0° in the state where lens LS is not arranged, the luminance ratio is set to 1. The (q) line and (r) line have a significantly increased luminance at a viewing angle of 0° compared to the (n) line, (o) line, and (p) line. That is, the most significant luminance increase effect was obtained when the thickness of lens LS was 5 μm and 6 μm.

[0084] From the optical simulation shown in Fig. 7, it was concluded that when reducing the refractive index of lens LS, it is necessary to increase the thickness of lens LS for luminance increase. In the example shown in Fig. 7, compared with the example shown in Fig. 6, the difference between the refractive index of lens LS and the refractive index of overcoat layer OC becomes smaller, so it becomes difficult for light to refract at the interface between lens LS and overcoat layer OC. Therefore, it is necessary to increase the inclined portion SP of lens LS, and the thickness of lens LS increases. Thus, the optimal thickness of lens LS depends on the refractive index of the material of lens LS.

[0085] [First Modified Example] Next, with reference to Fig. 8, the configuration of the first modified example will be described.

[0086] Fig. 8 is a cross-sectional view showing a first modified example of display panel PNL. The configuration shown in Fig. 8 is different from the configuration shown in Fig. 3 in that overcoat layer OC contains particles PC.

[0087] Overcoat layer OC contains either metal nanoparticles or hollow particles as particles PC. The metal nanoparticles are, for example, nano-titanium. By mixing nano-titanium into overcoat layer OC, the refractive index of overcoat layer OC can be improved. The hollow particles are, for example, hollow silica or hollow polymer. By mixing an air layer using hollow silica or hollow polymer in the overcoat layer OC, the refractive index of the overcoat layer OC can be decreased.

[0088] Also, when increasing the thickness T of the lens LS, it is necessary to increase the thickness of the overcoat layer OC. When the overcoat layer OC is formed only of resin, it is difficult to form the overcoat layer OC with a thickness of 4 μm or more, but by mixing the particles PC, the overcoat layer OC can be formed with a thickness of 4 μm or more. Even in such a first modification example, the same effects as described above can be obtained.

[0089] [Second Modification Example] Next, with reference to FIG. 9, the configuration of the second modification example will be described.

[0090] FIG. 9 is a plan view showing a second modification example of the display panel PNL. The configuration shown in FIG. 9 is different from the configuration shown in FIG. 2 mainly in that the respective anode openings AP11, AP12, AP13, AP14 are formed in a circular shape. FIG. 9 shows one pixel PX of the display panel PNL.

[0091] The pixel PX is composed of a sub-pixel SPX11 that displays green, a sub-pixel SPX12 that displays red, a sub-pixel SPX13 that displays blue, and a sub-pixel SPX14 that displays green. The sub-pixels SPX11 and SPX12 are arranged in the second direction Y, the sub-pixels SPX13 and SPX14 are arranged in the second direction Y, the sub-pixels SPX11 and SPX13 are arranged in the first direction X, and the sub-pixels SPX12 and SPX14 are arranged in the first direction X. Note that the size, arrangement, and color of each sub-pixel are not limited to the illustrated example.

[0092] The display panel PNL includes anode electrodes AN11, AN12, AN13, AN14, ribs RB, a light shielding layer BM, and a plurality of lenses LS.

[0093] The anode electrodes AN11, AN12, AN13, and AN14 are respectively disposed in the sub-pixels SPX11, SPX12, SPX13, and SPX14.

[0094] The rib RB has an anode opening AP11 that defines the sub-pixel SPX11, an anode opening AP12 that defines the sub-pixel SPX12, an anode opening AP13 that defines the sub-pixel SPX13, and an anode opening AP14 that defines the sub-pixel SPX14. The arrangement of the anode openings AP11 to AP14 is the same as the arrangement of the sub-pixels SPX11 to SPX14. The anode openings AP11 to AP14 are formed in a circular shape. The anode opening AP11 is formed at a position overlapping the anode electrode AN11. The anode opening AP12 is formed at a position overlapping the anode electrode AN12. The anode opening AP13 is formed at a position overlapping the anode electrode AN13. The anode opening AP14 is formed at a position overlapping the anode electrode AN14. The diameter D4 of each of the anode openings AP11, AP12, AP13, and AP14 is approximately 20 μm.

[0095] The width W61 along the first direction X between the anode opening AP11 and the anode opening AP13 is approximately 20 μm. The width W62 along the first direction X between the anode opening AP12 and the anode opening AP14 is approximately 20 μm. The width W71 along the second direction Y between the anode opening AP11 and the anode opening AP12 is approximately 20 μm. The width W72 along the second direction Y between the anode opening AP13 and the anode opening AP14 is approximately 20 μm. The widths W61, W62, W71, and W72 correspond to the width of the rib RB.

[0096] The light-shielding layer BM is disposed in the region indicated by hatching in the figure. The light-shielding layer BM overlaps with the rib RB in the entire region indicated by hatching in the figure. The light-shielding layer BM has a plurality of openings OP formed at positions overlapping with the anode openings AP11, AP12, AP13, and AP14. The openings OP are formed in a circular shape. The diameter of each opening OP is larger than the diameter D4 of each anode opening AP11, AP12, AP13, and AP14.

[0097] Since the configurations of the respective sub-pixels SPX11, SPX12, SPX13, and SPX14 are the same, hereinafter, the configuration will be mainly described by focusing on the sub-pixel SPX11. The anode opening AP11 has an edge EG4 which is the outer edge of the anode opening AP11.

[0098] The plurality of lenses LS are formed with equal sizes to each other and are formed in a circular shape in plan view. The diameter D of each lens LS is, for example, about 12 μm.

[0099] In the illustrated example, four lenses LS41, LS42, LS43, and LS44 are disposed with respect to the anode opening AP11. The lenses LS41, LS42, LS43, and LS44 overlap across the anode opening AP11, the edge EG4, and the rib RB, respectively. In the illustrated example, a part of each lens LS overlaps with the light-shielding layer BM.

[0100] As shown with reference to the lens LS41, the center O of the lens LS41 is located inside the edge EG4 of the anode opening AP11. Similarly for the other lenses LS, the center O of each lens LS is located inside the respective edges of the anode openings AP11, AP12, AP13, and AP14. The center O of the lens LS41 is located inside the edge EG4 by a length L3 in the radial direction of the edge EG4. The length L3 is, for example, about 3 μm. Even in such a second modification, the same effects as those described above can be obtained.

[0101] [Third Modification Example] Next, with reference to FIG. 10, the configuration of the third modification example will be described.

[0102] FIG. 10 is a cross-sectional view showing a third modification example of the display panel PNL. The configuration shown in FIG. 10 is different from the configuration shown in FIG. 3 in that the display panel PNL does not include a light shielding layer BM and a color filter layer CF.

[0103] The plurality of lenses LS are located on the sealing layer 40. The overcoat layer OC covers the plurality of lenses LS and the sealing layer 40. Further, the display panel PNL includes a polarizing plate PL. The polarizing plate PL is located on the sealing substrate 20. Also in such a third modification example, the same effects as those described above can be obtained.

[0104] As described above, according to the present embodiment, a display device capable of improving the light extraction efficiency can be obtained.

[0105] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention and are included in the invention described in the claims and its equivalent scope.

Explanation of Reference Numerals

[0106] DSP... Display device, 10... Insulating substrate, AN... Anode electrode, OR... Organic light emitting layer, OLED... Organic electroluminescence element, AP... Anode opening, RB... Rib, 40... Sealing layer, LS... Lens, OC... Overcoat layer, EG1, EG2, EG3, EG4, EG11, EG12, EG13, EG14... Edges BM... Light-shielding layer, OP... Opening CF... Color filter layer, CF1... First color filter, CF2... Second color filter PC... Particle, O... Center, LSE... Outer edge, SP... Tapered portion

Claims

1. An insulating substrate, An organic electroluminescence element located on the insulating substrate and including an anode electrode and an organic light-emitting layer, A rib located on the insulating substrate and having an anode opening at a position overlapping the anode electrode, A sealing layer that seals the organic electroluminescence element and the rib between the insulating substrate, A first lens located on the sealing layer, An overcoat layer covering the first lens, and a display device, The first lens overlaps across the anode opening, an edge of the anode opening, and the rib.

2. A light-shielding layer located on the sealing layer, A color filter layer located on the light-shielding layer and the sealing layer, and The first lens is located on the color filter layer. The display device according to claim 1.

3. The edge of the anode opening has a first edge and a second edge extending in a first direction, and a third edge and a fourth edge extending in a second direction intersecting the first direction, The first lens overlaps across the anode opening, the first edge and the third edge, and the rib. The display device according to claim 1.

4. The center of the first lens is located inside the edge of the anode opening. The display device according to claim 1.

5. The color filter layer has a first color filter of a first color and a second color filter of a second color different from the first color, The first color filter and the second color filter are adjacent to each other, The first lens overlaps the first color filter and does not overlap the second color filter. The display device according to claim 2.

6. The overcoat layer includes any one of metal nanoparticles and hollow particles. The display device according to claim 1.

7. Further includes a second lens, a third lens, and a fourth lens, The second lens, the third lens, and the fourth lens each overlap across the anode opening, the edge of the anode opening, and the rib. The display device according to claim 1.

8. Further includes a second lens, a third lens, and a fourth lens, The second lens overlaps across the anode opening, the first edge and the fourth edge, and the rib, The third lens overlaps across the anode opening, the second edge and the third edge, and the rib, The display device according to claim 3, wherein the fourth lens overlaps across the anode opening, the second edge, the fourth edge, and the rib.

9. The first lens has an inclined portion between the center of the first lens and the outer edge of the first lens, The display device according to claim 4, wherein the inclined portion overlaps the rib.

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