Display device

Abstract

A display device includes a pixel unit and a photoluminescent layer. Each pixel unit comprises a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first light emitting element and a first filter layer. The first filter layer is disposed over the first light emitting element. The second sub-pixel includes a second light emitting element and a second filter layer. The second filter layer is disposed over the second light emitting element. A portion of the photoluminescent layer is located between the first light-emitting element and the first filter layer and laterally covers a sidewall of the first light-emitting element. The other part of the photoluminescent layer is located between the second light-emitting element and the second filter layer and transversely covers the side wall of the second light-emitting element. The first sub-pixels and the second sub-pixels are configured to emit light rays of different colors.

Description

Technical Field

[0001] The present invention relates to a display device. Background Art

[0002] A micro light-emitting diode display device uses micro light-emitting diodes as light-emitting elements in pixels. As the size of the light-emitting elements gradually decreases, the pixel density (pixels per inch, PPI) increases, and the display device can thus achieve a display screen with higher resolution. However, when the size of the light-emitting elements decreases, many problems are relatively brought, such as the reduction of the external quantum efficiency of the light-emitting elements, which in turn affects the display quality of the display device. In addition, as the pixel size decreases, different light-emitting elements in the same pixel are prone to crosstalk with each other, resulting in color shift problems. Summary of the Invention

[0003] The present invention provides a display device with better light collection efficiency and lower color shift in the left / right viewing angle direction.

[0004] The display device of the present invention includes a pixel unit and a photoluminescent layer. The pixel unit includes a first sub-pixel and a second sub-pixel. The first sub-pixel includes a first light-emitting element and a first filter layer, and the first filter layer is disposed above the first light-emitting element. The second sub-pixel includes a second light-emitting element and a second filter layer, and the second filter layer is disposed above the second light-emitting element. A part of the photoluminescent layer is located between the first light-emitting element and the first filter layer and laterally covers the sidewall of the first light-emitting element, and another part of the photoluminescent layer is located between the second light-emitting element and the second filter layer and laterally covers the sidewall of the second light-emitting element. The first sub-pixel and the second sub-pixel are configured to emit light of different colors.

[0005] Based on the above, in the display device of the present invention, a part of the photoluminescent layer is located between the first light-emitting element and the first filter layer and laterally covers the sidewall of the first light-emitting element, and another part of the photoluminescent layer is located between the second light-emitting element and the second filter layer and laterally covers the sidewall of the second light-emitting element. The first sub-pixel and the second sub-pixel are configured to emit light of different colors. Thus, the display device has better light collection efficiency and energy-saving efficiency and lower color shift in the left / right viewing angle direction. Description of the Drawings

[0006] Figure 1A is a top view schematic diagram of one of the pixel units in the display device according to an embodiment of the present invention.

[0007] Figure 1BIt is a schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel in the display device according to an embodiment of the present invention.

[0008] Figure 1C It is a relationship diagram of the horizontal viewing angle and the relative intensity according to an embodiment of the present invention.

[0009] Figure 1D It is a relationship diagram of the horizontal viewing angle and the relative intensity according to an embodiment of the present invention.

[0010] Figure 1E It is a relationship diagram of the horizontal viewing angle and the relative intensity according to an embodiment of the present invention.

[0011] Figure 2 It is a schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention.

[0012] Figure 3 It is a schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention.

[0013] Figure 4 It is a schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention.

[0014] The reference numerals are explained as follows:

[0015] 110A, 110B, 110C, 110D: Pixel units

[0016] 110: First substrate

[0017] 110T: Top surface

[0018] 112: First sub-pixel

[0019] 112A: First light-emitting element

[0020] 112B: First color conversion structure

[0021] 112C: First light filter layer

[0022] 114: Second sub-pixel

[0023] 114A: Second light-emitting element

[0024] 114B: Second color conversion structure

[0025] 114C: Second light filter layer

[0026] 116: Third sub-pixel

[0027] 116A: Third light-emitting element

[0028] 116C: Third light filtering layer

[0029] 118: Fourth sub-pixel

[0030] 118A: Fourth light-emitting element

[0031] 118C: Fourth light filtering layer

[0032] 120: Second substrate

[0033] 120B: Bottom surface

[0034] 130: Reflective layer

[0035] BM, BM’, BM”: Masking element

[0036] D1: First direction

[0037] D2: Second direction

[0038] D3: Third direction

[0039] H: Height

[0040] L1, L2, L3, L4, L5: Length

[0041] S: Stitching seam

[0042] SL, SL’, SL”: Scattering layer

[0043] SP: Scattering particle

[0044] WB: Barrier layer

[0045] YL: Photoluminescent layer

[0046] YP: Diffusion particle

[0047] W1, W2, W3, W4, W5, W9, W10: Width

[0048] W6, W7, W8: Spacing. Detailed implementation manners

[0049] Figure 1A is a top view schematic diagram of one pixel unit in a display device according to an embodiment of the present invention. In some embodiments, the display device is a tiled display device including multiple display panels, Figure 1B is a cross-sectional schematic diagram of one pixel unit in a display device according to an embodiment of the present invention and the stitching seam S between the display panels, where Figure 1B shows a cross-sectional schematic diagram along Figure 1A the line I-I’ in Figure 1A and Figure 1B. A display device includes a pixel unit 110A. The pixel unit 110A includes a first sub-pixel 112 and a second sub-pixel 114. The first sub-pixel 112 includes a first light-emitting element 112A and a first filter layer 112C. The first filter layer 112C is disposed above the first light-emitting element 112A. The second sub-pixel 114 includes a second light-emitting element 114A and a second filter layer 114C. The second filter layer 114C is disposed above the second light-emitting element 114A. The first light-emitting element 112A and the second light-emitting element 114A emit light of the same color (or light of a first color). For example, the first light-emitting element 112A and the second light-emitting element 114A are both blue light-emitting diodes, and the light of the first color is blue light.

[0050] The light-emitting element may, for example, include an organic light emitting diode (OLED) or a micro light emitting diode (micro LED), but is not limited thereto.

[0051] The display device further includes a photoluminescent layer YL. A part of the photoluminescent layer YL is located between the first light-emitting element 112A and the first filter layer 112C, and another part of the photoluminescent layer YL is located between the second light-emitting element 114A and the second filter layer 114C. The photoluminescent layer YL laterally covers the sidewalls of the first light-emitting element 112A and the second light-emitting element 114A. The photoluminescent layer YL is adapted to convert the light of the first color emitted by the first light-emitting element 112A and the second light-emitting element 114A into light of a second color. For example, the photoluminescent layer YL absorbs at least part of the light of the first color emitted by the first light-emitting element 112A and the second light-emitting element 114A, and emits light of the second color. For example, the light of the second color is yellow light.

[0052] Since the display device includes the photoluminescent layer YL, the brightness of the first sub-pixel 112 in the display device can be increased, for example, by 15.53 nit, and the brightness of the second sub-pixel 114 can be increased, for example, by 2.79 nit. At the same time, the display device has an energy-saving efficiency as high as 47% compared with traditional display devices. In addition, a surface light source can be formed in the display device through the arrangement of the photoluminescent layer YL to perform characteristic supplementary lighting, further improving the visual problem of the splicing seam S.

[0053] The first filter layer 112C is disposed above the photoluminescent layer YL and is adapted to filter the light of the second color into light of a third color. For example, the first filter layer 112C is a red filter layer, and yellow light is filtered into red light after passing through the red filter layer.

[0054] The first sub-pixel 112 further includes a first color conversion structure 112B. The first color conversion structure 112B is disposed above the first light-emitting element 112A and is located between the photoluminescent layer YL and the first filter layer 112C. A part of the photoluminescent layer YL is located between the first color conversion structure 112B and the first light-emitting element 112A.

[0055] In some embodiments, the photoluminescent layer YL includes photoluminescent particles and diffusing particles YP. The photoluminescent layer YL is, for example, a fluorescent material, a phosphorescent material, or other suitable materials. The photoluminescent layer YL includes a substrate (such as a photoresist or other organic materials), and the photoluminescent particles and the diffusing particles YP are dispersed in the substrate.

[0056] In some embodiments, the weight percentage concentration of the photoluminescent particles in the photoluminescent layer YL falls within the range of 40% to 60%, and the weight percentage concentration of the diffusing particles YP falls within the range of 0.5% to 20%. In some embodiments, the particle size of the photoluminescent particles falls within the range of 0.1 micrometer to 5 micrometers, and the size of the diffusing particles YP falls within the range of 0.1 micrometer to 1 micrometer. The material of the diffusing particles YP is, for example, titanium dioxide or other suitable materials.

[0057] In the present embodiment, the photoluminescent layer YL can absorb the light emitted by the first light-emitting element 112A or the second light-emitting element 114A (the wavelength range is, for example, about 425 nm to 495 nm) and emit light of other colors (the wavelength range is about 425 nm to 750 nm). The first color conversion structure 112B can absorb the light emitted by the photoluminescent layer YL and emit light of another converted color (the wavelength range is about 620 nm to 750 nm). The second color conversion structure 114B can absorb the light emitted by the photoluminescent layer YL and emit light of yet another color (the wavelength range is about 495 nm to 570 nm), but is not limited thereto.

[0058] The pixel unit 110A further includes a third sub-pixel 116. The third sub-pixel 116 includes a third light-emitting element 116A and a third filter layer 116C. The third light-emitting element 116A emits the same color of light (or the light of the first color) as the first light-emitting element 112A and the second light-emitting element 114A. The third filter layer 116C is a blue filter layer. Another part of the photoluminescent layer YL is located between the third light-emitting element 116A and the third filter layer 116C. The photoluminescent layer YL laterally covers the sidewall of the third light-emitting element 116A. The light emitted by the third light-emitting element 116A (the wavelength range is, for example, about 425 nm to 495 nm), and the photoluminescent layer YL can absorb the light emitted by the third light-emitting element 116A and emit light of other colors (the wavelength range is about 425 nm to 750 nm), which is filtered into blue by the third filter layer 116C.

[0059] The pixel unit 110A further includes a fourth sub-pixel 118. The fourth sub-pixel 118 includes a fourth light-emitting element 118A and a fourth filter layer 118C. The fourth light-emitting element 118A emits light of the same color (or light of a first color) as the first light-emitting element 112A, the second light-emitting element 114A, and the third light-emitting element 116A. The fourth filter layer 118C is disposed on the fourth light-emitting element 118A. The fourth filter layer 118C is a yellow filter layer. Another part of the photoluminescent layer YL is located between the fourth light-emitting element 118A and the fourth filter layer 118C. The photoluminescent layer YL laterally covers the sidewall of the fourth light-emitting element 118A. The photoluminescent layer YL is adapted to absorb the light emitted by the fourth light-emitting element 118A (with a wavelength range, for example, of about 425 nm to 495 nm) and emit light of other colors (with a wavelength range of about 425 nm to 750 nm), which is filtered into yellow by the fourth filter layer 118C.

[0060] The peak wavelength of the light emitted by the photoluminescent layer YL falls within the range of 540 nanometers to 580 nanometers, and the full width at half maximum of the wavelength falls within the range less than 125 nanometers. The light emitted by the first color conversion structure 112B has a peak wavelength falling within the range of 614 nanometers to 625 nanometers, and the full width at half maximum of the wavelength falls within the range less than 50 nanometers. The peak wavelength of the light emitted by the second color conversion structure 114B falls within the range of 515 nanometers to 525 nanometers, and the full width at half maximum of the wavelength falls within the range less than 50 nanometers.

[0061] The display device further includes a first substrate 110 and a second substrate 120. The first substrate 110 and the second substrate 120 can be transparent substrates. In the third direction D3 (in the Z-axis direction), the second substrate 120 is disposed on the first substrate 110, and the first substrate 110 overlaps the second substrate 120. The first light-emitting element 112A and the second light-emitting element 114A are disposed on the first substrate 110. The material of the first substrate 110 or the second substrate 120 may include glass, quartz, or other suitable materials, or a combination of the above materials, but the present invention is not limited thereto.

[0062] The first light-emitting element 112A and the second light-emitting element 114A are disposed on the first substrate 110 and located between the first substrate 110 and the second substrate 120. The first substrate 110 can be an active element substrate or other substrates that can be used to provide driving signals and / or power to the sub-pixels, such as the first sub-pixel 112 and the second sub-pixel 114. The bottom surface 120B of the second substrate 120 and the top surface 110T of the first substrate 110 may have a height H in the third direction D3, and the height H falls within the range of 5 micrometers to 15 micrometers.

[0063] The pixel unit 100A further includes a barrier layer WB. The barrier layer WB is disposed between the first substrate 110 and the second substrate 120 and is located between the photoluminescent layer YL and the second substrate 120. The material of the barrier layer WB may include black photoresist, white photoresist, photoresist of other colors, or metal, but is not limited thereto. In some embodiments, the material of the barrier layer WB may further include light-scattering particles. The material of the light-scattering particles may be, for example, titanium dioxide, but is not limited thereto.

[0064] The pixel unit 100A further includes a plurality of shielding elements BM. The plurality of shielding elements BM may be disposed on the surface of the second substrate 120 facing the first substrate 110 and is located between the barrier layer WB and the second substrate 120. The material of the plurality of shielding elements BM may include black resin, gray resin, white resin, titanium black, or carbon black, but is not limited thereto.

[0065] Figure 1C It is a graph showing the relationship between the horizontal viewing angle and the relative intensity according to an embodiment of the present invention. Figure 1D It is a graph showing the relationship between the horizontal viewing angle and the relative intensity according to an embodiment of the present invention. Figure 1E It is a graph showing the relationship between the horizontal viewing angle and the relative intensity according to an embodiment of the present invention. Please refer to Figures 1C to 1E . Figure 1C When the weight percentage concentration of the diffusing particles YP in the photoluminescent layer YL is in the range of 0%, Figure 1D When the weight percentage concentration of the diffusing particles YP in the photoluminescent layer YL falls within the range of 1.5%, and Figure 1E When the weight percentage concentration of the diffusing particles YP in the photoluminescent layer YL falls within the range of 3%, comparing Figure 1C and Figure 1D and Figure 1E it can be found that when the weight percentage concentration of the diffusing particles YP in the photoluminescent layer YL gradually increases from 0% to 1.5% and finally rises to 3%, the display device significantly exhibits a better light-concentrating effect. Therefore, gradually increasing the weight percentage concentration of the diffusing particles YP in the photoluminescent layer YL can effectively improve the light-concentrating effect of the display device and reduce the color shift in the left / right viewing angle direction.

[0066] As Figure 1A and Figure 1BIt is described that the width of the shielding element BM in the first direction D1 is W1, the length of the shielding element BM in the second direction D2 is L1. In the first direction D1, the opening width W2 of the blocking layer WB of the first sub-pixel 112, the opening width W3 of the blocking layer WB of the second sub-pixel 114, the opening width W4 of the blocking layer WB of the third sub-pixel 116, and the opening width W5 of the blocking layer WB of the fourth sub-pixel 118. In the second direction D2, the opening length L2 of the blocking layer WB of the first sub-pixel 112, the opening length L3 of the blocking layer WB of the second sub-pixel 114, the opening length L4 of the blocking layer WB of the third sub-pixel 116, and the opening length L5 of the blocking layer WB of the fourth sub-pixel 118. There is a spacing W6 between the first light-emitting element 112A and the second light-emitting element 114A, a spacing W7 between the second light-emitting element 114A and the third light-emitting element 116A, and a spacing W8 between the third light-emitting element 116A and the fourth light-emitting element 118A.

[0067] In this embodiment, when W1 and W6 - W8 increase simultaneously, the optical crosstalk between the first light-emitting element 112A and the second light-emitting element 114A, between the second light-emitting element 114A and the third light-emitting element 116A, or between the third light-emitting element 116A and the fourth light-emitting element 118A can thus be reduced. In some embodiments, when W1 and W2 - W8 also increase simultaneously, the optical crosstalk between the first light-emitting element 112A and the second light-emitting element 114A, between the second light-emitting element 114A and the third light-emitting element 116A, or between the third light-emitting element 116A and the fourth light-emitting element 118A can also be reduced, but the present invention is not limited thereto.

[0068] In some embodiments, when the weight percentage concentration of the diffused particles YP in the photoluminescent layer YL increases from 0.5% to 2% and then to 3.5%, the optical crosstalk between the first light-emitting element 112A and the second light-emitting element 114A, between the second light-emitting element 114A and the third light-emitting element 116A, or between the third light-emitting element 116A and the fourth light-emitting element 118A can also be reduced.

[0069] Figure 2Schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention. Pixel unit 100B is similar to pixel unit 100A, and the main difference is that the scattering layer SL is located on the third light-emitting element 116A and laterally covers the side wall of the third light-emitting element 116A. The scattering layer SL' is located between the scattering layer SL and the third light-filtering layer 116C and laterally covers the side wall of a part of the barrier layer WB. The scattering layer SL and the scattering layer SL' contain scattering particles SP, and the scattering particles SP can be, for example, titanium dioxide particles. The third light-filtering layer 116C is disposed on the scattering layer SL'. Since the scattering layer SL is located on the third light-emitting element 116A and laterally covers the side wall of the third light-emitting element 116A, and the scattering layer SL' is located between the scattering layer SL and the third light-filtering layer 116C and laterally covers the side wall of a part of the barrier layer WB, the third light-emitting element 116A can avoid total internal reflection, enabling the display device to have better light-concentration efficiency and lower color shift in the left / right viewing angle direction.

[0070] Figure 3 Schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention. Pixel unit 100C is similar to pixel unit 100A, and the main difference is that the scattering layer SL'' is located between the third light-filtering layer 116C and yet another part of the photoluminescent layer YL and laterally covers the side wall of a part of the barrier layer WB. The shielding element BM' can be located between the first light-emitting element 112A and the second light-emitting element 114A, between the second light-emitting element 114A and the third light-emitting element 116A, and between the third light-emitting element 116A and the fourth light-emitting element 118A and has a width W10. The reflective layer 130 can be located between the first light-emitting element 112A and the shielding element BM', between the second light-emitting element 114A and the shielding element BM', between the third light-emitting element 116A and the shielding element BM', and between the fourth light-emitting element 118A and the shielding element BM' and has a width W9. The width W10 is greater than or equal to the width W9. Since the width W10 of the shielding element BM' is greater than or equal to the width W9 of the reflective layer 130, in this way, the optical crosstalk between sub-pixels can be reduced accordingly, and the display device can thus improve the light-emitting efficiency.

[0071] In some embodiments, the ratio of the width W10 of the shielding element BM' to the width W9 of the reflective layer 130 falls within the range of 1 to 2.5.

[0072] Figure 4Schematic cross-sectional view of the splicing seam S between one pixel unit and the display panel according to another embodiment of the present invention. Pixel unit 100D is similar to pixel unit 100C. The main difference is that pixel unit 100D further includes a shielding element BM" disposed within the barrier layer WB. The shielding element BM is disposed on the side of the second substrate 120 facing the first substrate 110. The shielding element BM" overlaps the shielding element BM. The barrier layer WB laterally covers the shielding element BM", and the light transmittance of the shielding element BM for visible light is lower than that of the barrier layer WB for visible light. Since the light transmittance of the shielding element BM for visible light is lower than that of the barrier layer WB for visible light, thus, the shielding element BM" can suppress the transmission of visible light, and the optical crosstalk between sub-pixels can be reduced accordingly, and the luminous efficiency of the display device can be improved accordingly. In some embodiments, the shielding element BM" can also laterally cover the barrier layer WB, but not limited thereto.

[0073] In summary, in the display device of the present invention, part of the photoluminescent layer is located between the first light-emitting element and the first light-filtering layer and laterally covers the sidewall of the first light-emitting element, and another part of the photoluminescent layer is located between the second light-emitting element and the second light-filtering layer and laterally covers the sidewall of the second light-emitting element. The first sub-pixel and the second sub-pixel are configured to emit light of different colors. Thus, the display device has better light-concentration efficiency and energy-saving efficiency and lower color shift in the left / right viewing angle direction.

Claims

1. A display device, comprising: A photoluminescent layer; And A pixel unit, comprising: A first sub-pixel, comprising: A first light-emitting element; and A first filter layer disposed above the first light-emitting element, wherein a portion of the photoluminescent layer is located between the first light-emitting element and the first filter layer, and the photoluminescent layer laterally covers the sidewall of the first light-emitting element; and A second sub-pixel, comprising: A second light-emitting element; and A second filter layer disposed above the second light-emitting element, wherein another portion of the photoluminescent layer is located between the second light-emitting element and the second filter layer, and the photoluminescent layer laterally covers the sidewall of the second light-emitting element, Wherein the first sub-pixel and the second sub-pixel are configured to emit light of different colors.

2. The display device according to claim 1, wherein the first sub-pixel further comprises a first color conversion structure, the second sub-pixel further comprises a second color conversion structure, the first color conversion structure is disposed on the first light-emitting element, the portion of the photoluminescent layer is located between the first color conversion structure and the first light-emitting element, the second color conversion structure is disposed on the second light-emitting element, and the another portion of the photoluminescent layer is located between the second color conversion structure and the second light-emitting element.

3. The display device according to claim 2, wherein the photoluminescent layer comprises photoluminescent particles and diffusion particles, the size of the photoluminescent particles falls within the range of 0.1 micrometer to 5 micrometers, the size of the diffusion particles falls within the range of 0.1 micrometer to 1 micrometer, the weight percentage concentration of the photoluminescent particles in the photoluminescent layer falls within the range of 40% to 60%, and the weight percentage concentration of the diffusion particles in the photoluminescent layer falls within the range of 0.5% to 20%.

4. The display device according to claim 1, wherein the pixel unit further comprises: A third sub-pixel comprising: A third light-emitting element; and A third filter layer disposed on the third light-emitting element, wherein yet another portion of the photoluminescent layer is located between the third light-emitting element and the third filter layer, and the photoluminescent layer laterally covers the sidewall of the third light-emitting element; and A fourth sub-pixel, comprising: A fourth light-emitting element; and A fourth filter layer disposed on the fourth light-emitting element, wherein still another portion of the photoluminescent layer is located between the fourth light-emitting element and the fourth filter layer, and the photoluminescent layer laterally covers the sidewall of the fourth light-emitting element, wherein the first sub-pixel, the second sub-pixel, the third sub-pixel, and the fourth sub-pixel are configured to emit light of different colors.

5. The display device according to claim 1, further comprising: A shielding element located between the first light-emitting element and the second light-emitting element, wherein the shielding element has a first width between the first light-emitting element and the second light-emitting element; And A reflective layer, located between the first light-emitting element and the shielding element and between the second light-emitting element and the shielding element, wherein a width of the reflective layer between the first light-emitting element and the shielding element and a width of the reflective layer between the second light-emitting element and the shielding element are each a second width, and the first width is greater than or equal to the second width.

6. The display device according to claim 5, wherein a ratio of the second width to the first width falls within a range of 1 to 2.

5.

7. The display device according to claim 1, further comprising: A first substrate, on which the first light-emitting element and the second light-emitting element are disposed; And A second substrate, overlapping the first substrate, on which the first light-filtering layer and the second light-filtering layer are disposed, the first light-emitting element, the second light-emitting element, the first light-filtering layer, the second light-filtering layer, and the photoluminescent layer are located between the first substrate and the second substrate, and the photoluminescent layer is located between the second substrate and the first light-emitting element and between the second substrate and the second light-emitting element.

8. The display device according to claim 7, wherein the pixel unit further comprises: A barrier layer, disposed between the photoluminescent layer and the second substrate; A first shielding element, disposed on a side of the second substrate facing the first substrate; And A second shielding element, overlapping the first shielding element, the barrier layer laterally covering the second shielding element, and a light transmittance of the first shielding element for visible light is lower than a light transmittance of the barrier layer for visible light.

9. The display device according to claim 8, wherein a material of the barrier layer comprises titanium dioxide.

10. The display device according to claim 8, wherein materials of the first shielding element and the second shielding element comprise titanium black or carbon black.

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