CN115732528A - Bottom-emission type light emitting diode display - Google Patents
Bottom-emission type light emitting diode display Download PDFInfo
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- CN115732528A CN115732528A CN202111019928.0A CN202111019928A CN115732528A CN 115732528 A CN115732528 A CN 115732528A CN 202111019928 A CN202111019928 A CN 202111019928A CN 115732528 A CN115732528 A CN 115732528A
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- emitting diode
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Abstract
A bottom emission type light emitting diode display includes a transparent substrate; a plurality of light emitting diodes bonded to the substrate; a packaging layer formed on the substrate to cover the light emitting diode; and the reflecting layer is formed on the packaging layer and used for reflecting the light emitted by the light-emitting diode. Wherein the reflective layer has a non-smooth shape or the encapsulation layer has a different refractive index.
Description
Technical Field
The present invention relates to a bottom-emission (LED) display, and more particularly, to a bottom-emission (LED) display with high light emission efficiency.
Background
A micro light emitting diode (micro LED, mLED or μ LED) display panel is one of flat panel displays (flat panel displays), which is composed of individual micro light emitting diodes (microscopic) with a size scale of 1-10 μm. Compared with the conventional liquid crystal display panel, the micro-led display panel has a larger contrast ratio, a faster response time, and consumes less power. Although micro light emitting diodes (OLEDs) have low power consumption characteristics as well as Organic Light Emitting Diodes (OLEDs), micro light emitting diodes have higher brightness, higher light emitting performance and longer lifetime than organic light emitting diodes because they use iii-v diode technology (e.g., gan).
A bottom emission type light emitting diode display is one of light emitting diode displays in which light emitting diodes emit light downward. In the bottom emission type led display, light emitted from the leds is first reflected and then travels downward, but may be blocked by bonding pads (bonding pads) of the leds or corresponding contact regions (e.g., electrode traces) of the substrate, thereby reducing light emission efficiency. In addition, the reflected light may be absorbed by the led, thereby further reducing the luminous efficacy.
Therefore, it is desirable to provide a novel bottom emission led display to overcome the shortcomings of the conventional bottom emission led display.
Disclosure of Invention
In view of the foregoing, an objective of the embodiments of the invention is to provide a bottom emission type light emitting diode display having a non-smooth (non-smooth) reflective/encapsulation layer or an encapsulation layer with different refractive indexes (reflectivity), which can improve the performance.
According to an embodiment of the present invention, a bottom emission type light emitting diode display includes a transparent substrate, a plurality of light emitting diodes, an encapsulation layer, and a reflection layer. The light emitting diode is bonded to the substrate. The packaging layer is formed on the substrate to cover the light emitting diode. The reflecting layer is formed on the packaging layer to reflect the light emitted by the light emitting diode. In one embodiment, the reflective layer has a non-smooth shape. In another embodiment, the encapsulation layers have different refractive indices.
Drawings
Fig. 1 is a cross-sectional view showing a bottom emission type led display according to a first embodiment of the present invention.
Fig. 2 is a cross-sectional view of a bottom emission type led display according to a second embodiment of the present invention.
Fig. 3 is a cross-sectional view of a bottom emission type led display according to a third embodiment of the present invention.
Fig. 4 is a cross-sectional view of a bottom emission type led display according to a fourth embodiment of the present invention.
Fig. 5 is a cross-sectional view of a bottom emission type led display according to a fifth embodiment of the present invention.
Fig. 6 is a cross-sectional view of a bottom emission type led display according to a sixth embodiment of the present invention.
Fig. 7 is a cross-sectional view showing a bottom emission type light emitting diode display according to a seventh embodiment of the present invention.
Fig. 8 is a cross-sectional view showing a bottom emission type led display according to an eighth embodiment of the present invention.
[ description of main element symbols ]
100 bottom emission type light emitting diode display
200 bottom emission type light emitting diode display
300 bottom emission type light emitting diode display
400 bottom emission type light emitting diode display
500 bottom-emitting type led display
600 bottom luminous type LED display
700 bottom emission type light emitting diode display
800 bottom-emission type light emitting diode display
11 substrate
12 light emitting diode
13 bonding pad
14 encapsulation layer
14 a-14 d packaging sub-layers
141-143 direction of light travel
144 particles
15 reflective layer
151 depression of
152, a bump
153 cavity
154 polygonal surface
155 nanoparticles
Detailed Description
Fig. 1 is a cross-sectional view of a bottom-emission light-emitting diode (LED) display 100 according to a first embodiment of the present invention.
In the present embodiment, the bottom emission type light emitting diode display (hereinafter, referred to as a display) 100 may include a transparent substrate 11, such as glass. The led 12 may be (flip) bonded to the substrate 11 via bonding pads 13, such as solder bumps. The display 100 of the present embodiment may include a packaging layer (packaging layer) 14 formed on the substrate 11 to cover the light emitting diodes 12.
In the present embodiment, the display 100 may include a reflective layer 15 formed on the encapsulation layer 14 to reflect light emitted by the light emitting diode 12. According to one of the features of this embodiment, the reflective layer 15 and/or the encapsulation layer 14 has a non-smooth (outer) shape or surface. In the present embodiment, the reflective layer 15 has a recess 151, which is bent toward the light emitting diode 12 and aligned with the light emitting diode 12 (in the present embodiment, the red light emitting diode, the green light emitting diode, and the blue light emitting diode).
Compared to the conventional bottom emission type LED display with a smooth reflective layer, the light reflected by the reflective layer 15 has more directions (as shown by the arrows) according to the display 100 shown in FIG. 1. Thereby, the reflected light is more likely to avoid the bonding pad 13 of the led 12 and the corresponding contact region (not shown) of the substrate 11. In addition, the reflected light is more likely to avoid being absorbed by the light emitting diode 12. Therefore, the luminous efficacy of the display 100 can be greatly improved.
In the present embodiment, the encapsulation layer 14 may include a transparent material with high transmittance (transmittance), such as photoresist, epoxy resin (epoxy resin), silicon-based glue (silicon-based glue), acrylic (acrylic) or polymer (polymer). The reflective layer 15 may comprise a reflective material (e.g., reflectivity greater than 70%), such as a metal coating, a reflective film, or a reflective glue.
In one embodiment, the non-smooth shape (of the encapsulation layer 14) of the display 100 may be formed using semiconductor processing. For example, a mask having regions with different transmittances, such as a half-tone mask (half-tone mask) or a slit mask (slit mask), may be used to form a specific structure, such as the recess 151. In another embodiment, a certain area may be subjected to multiple lithography exposures to form a specific structure, such as the recess 151.
In another embodiment, the non-smooth shape of the display 100 may be formed using a coating process. For example, coating techniques such as inkjet printing, screen printing, spraying or dispensing may be used to form the specific structures (e.g., the recesses 151), possibly in combination with molding. In another embodiment, a compression molding technique (compression molding) may be used to adjust the viscosity (viscocity) of the coating material to form a specific structure, such as the recess 151.
In yet another embodiment, the non-smooth shape of the display 100 may be formed using an adhesive technique (adhesion). For example, a film having a pre-fabricated structure may be used to form a particular structure, such as recess 151.
Fig. 2 is a cross-sectional view of a bottom emission type led display 200 according to a second embodiment of the present invention. A bottom emission type light emitting diode display (hereinafter referred to as a display) 200 is similar to the display 100 of fig. 1, and differences thereof are described below.
The reflective layer 15 or/and the encapsulation layer 14 of the present embodiment has a non-smooth (outer) shape or surface. In the present embodiment, the reflective layer 15 has a plurality of recesses 151 respectively bending toward the light emitting diodes 12 (e.g., red, green, and blue light emitting diodes) and respectively aligned with the light emitting diodes 12.
Fig. 3 is a cross-sectional view of a bottom emission type led display 300 according to a third embodiment of the present invention. A bottom emission type light emitting diode display (hereinafter referred to as a display) 300 is similar to the display 100 of fig. 1, and differences thereof are described below.
The reflective layer 15 of this embodiment has a non-smooth (outer) shape or surface. In the present embodiment, the reflective layer 15 has a plurality of bumps (covex bump) 152 protruding outward away from the light emitting diode 12.
Fig. 4 is a cross-sectional view of a bottom emission type led display 400 according to a fourth embodiment of the present invention. A bottom emission type light emitting diode display (hereinafter referred to as a display) 400 is similar to the display 100 of fig. 1, and differences thereof are described below.
The reflective layer 15 of this embodiment has a non-smooth (outer) shape or surface. In this embodiment, the reflective layer 15 has a plurality of concave cavities (concave cavities) 153, which are recessed inward facing the light emitting diodes 12.
Fig. 5 is a cross-sectional view of a bottom emission type led display 500 according to a fifth embodiment of the present invention. The bottom emission type light emitting diode display (hereinafter, referred to as a display) 500 is similar to the display 100 of fig. 1, and the differences thereof are explained as follows.
The reflective layer 15 of this embodiment has a non-smooth (outer) shape or surface. In the present embodiment, the reflective layer 15 has a (convex) polyhedral shape having a plurality of polygonal (polygon) surfaces 154.
Fig. 6 is a cross-sectional view of a bottom emission type led display 600 according to a sixth embodiment of the present invention. A bottom emission type light emitting diode display (hereinafter, referred to as a display) 600 is similar to the display 100 of fig. 1, and the differences thereof are explained as follows.
The reflective layer 15 of this embodiment has a non-smooth (outer) shape or surface. In the present embodiment, the surface of the reflective layer 15 has an irregular (irregular) shape. In one embodiment, the nano-particles (nanoparticles) 155 cover the encapsulation layer 14, and the reflective layer 15 is formed on the nano-particles 155, thereby forming irregular shapes on the outer surface of the reflective layer 15.
Fig. 7 is a cross-sectional view of a bottom emission type led display 700 according to a seventh embodiment of the present invention.
In the present embodiment, a bottom emission type light emitting diode display (hereinafter, referred to as a display) 700 may include a transparent substrate 11, such as glass. The led 12 may be (flip) bonded to the substrate 11 by bonding pads (or solder bumps) 13. The display 700 of the present embodiment may include an encapsulation layer 14 formed on the substrate 11 to cover the light emitting diodes 12; and may include a reflective layer 15 formed on the encapsulation layer 14 to reflect light emitted by the led 12.
According to one feature of this embodiment, the encapsulation layer 14 may include a plurality of encapsulation sub-layers (e.g., 14 a-14 d) sequentially covering the light emitting diode 12 from the light emitting diode 12 to the reflective layer 15. In particular, in this embodiment, the refractive index of the lower (or inner) encapsulation sub-layer is higher than the refractive index of the upper (or outer) encapsulation sub-layer.
According to the display 700 shown in FIG. 7, the light emitted from the LEDs 12 may be reflected in a direction different from the original direction. As shown in fig. 7, due to the high refractive index of the package sub-layer 14a, some of the light emitted from the led 12 is totally reflected (total reflection) (as shown by the arrow 141). Other light emitted by the led 12 is sequentially refracted by the sub-package layers 14 a-14 d (as shown by arrow 142), and finally reflected by the reflective layer 15. Other light emitted from the led 12 is refracted by the package sub-layers 14 a-14 c sequentially, and then is totally reflected (as shown by arrow 143) due to the low refractive index of the package sub-layer 14 d.
Fig. 8 is a cross-sectional view of a bottom emission type led display 800 according to an eighth embodiment of the present invention.
In the present embodiment, a bottom emission type light emitting diode display (hereinafter, referred to as a display) 800 may include a transparent substrate 11, such as glass. The led 12 may be (flip) bonded to the substrate 11 by bonding pads (or solder bumps) 13. The display 800 of the present embodiment may include an encapsulation layer 14 formed on the substrate 11 to cover the light emitting diodes 12; and may include a reflective layer 15 formed on the encapsulation layer 14 to reflect light emitted by the led 12.
According to one of the features of the present embodiment, particles 144 or powder having different refractive indexes are added to the encapsulation layer 14, so that the traveling direction of the light emitted from the light emitting diode 12 is changed by the particles 144 or powder (as shown by arrows). In this embodiment, the particles 144 or powder may be a powder having a high refractive index, such as a quantum dot (quantum dot) powder or metal spheres.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the scope of the present invention; it is intended that all such equivalent changes and modifications be included within the scope of the present invention as defined by the appended claims.
Claims (20)
1. A bottom emission type light emitting diode display, comprising:
a transparent substrate;
a plurality of light emitting diodes bonded to the substrate;
a packaging layer formed on the substrate to cover the light emitting diode; and
the reflecting layer is formed on the packaging layer and used for reflecting the light emitted by the light-emitting diode;
wherein the reflective layer has a non-smooth shape.
2. The bottom-emission light-emitting diode display defined in claim 1 wherein the substrate comprises glass.
3. The bottom-emission type led display of claim 1, further comprising:
and the bonding pads are used for bonding the light-emitting diode to the substrate.
4. The bottom-emission light-emitting diode display defined in claim 1, wherein the encapsulation layer comprises a transparent material.
5. The bottom-emission light-emitting diode display defined in claim 1 wherein the reflective layer comprises a reflective material having a reflectivity of greater than 70%.
6. The bottom-emission type led display of claim 1, wherein the reflective layer has recesses curved toward and aligned with the red, green and blue leds.
7. The bottom-emission light-emitting diode display device according to claim 1, wherein said reflective layer has a plurality of recesses respectively curved toward and aligned with said plurality of light-emitting diodes.
8. The bottom-emission light-emitting diode display defined in claim 1 wherein the reflective layer has a plurality of bumps that project away from the light-emitting diodes.
9. The bottom-emission light-emitting diode display defined in claim 1, wherein the reflective layer has a plurality of concave cavities that are concave inward facing the light-emitting diodes.
10. The bottom-emission light-emitting diode display defined in claim 1, wherein the reflective layer has a polyhedral shape having a plurality of polygonal surfaces.
11. The bottom-emission type led display of claim 1, further comprising:
and the nano particles are arranged between the packaging layer and the reflecting layer, so that the reflecting layer forms an irregular shape.
12. A bottom emission type light emitting diode display, comprising:
a transparent substrate;
a plurality of light emitting diodes bonded to the substrate;
a packaging layer formed on the substrate to cover the light emitting diode; and
the reflecting layer is formed on the packaging layer and used for reflecting the light emitted by the light-emitting diode;
wherein the encapsulation layers have different refractive indices.
13. The bottom-emission light-emitting diode display defined in claim 12 wherein the substrate comprises glass.
14. The bottom-emission light-emitting diode display of claim 12, further comprising:
and the bonding pad is used for bonding the light-emitting diode to the substrate.
15. The bottom-emission light-emitting diode display defined in claim 12 wherein the encapsulation layer comprises a transparent material.
16. The bottom-emission light-emitting diode display according to claim 12, wherein the reflective layer comprises a reflective material having a reflectivity higher than 70%.
17. The bottom-emission type led display of claim 12, wherein the encapsulation layer comprises a plurality of encapsulation sub-layers sequentially covering the leds from the leds to the reflective layer.
18. The bottom-emission light-emitting diode display defined in claim 17 wherein the lower package sub-layer has a higher refractive index than the upper package sub-layer.
19. The bottom-emission light-emitting diode display defined in claim 12 wherein the encapsulating layer incorporates particles having different refractive indices.
20. The bottom-emission light-emitting diode display defined in claim 19 wherein the particles comprise powders, quantum dot powders, or metal spheres.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111019928.0A CN115732528A (en) | 2021-09-01 | 2021-09-01 | Bottom-emission type light emitting diode display |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111019928.0A CN115732528A (en) | 2021-09-01 | 2021-09-01 | Bottom-emission type light emitting diode display |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115732528A true CN115732528A (en) | 2023-03-03 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111019928.0A Pending CN115732528A (en) | 2021-09-01 | 2021-09-01 | Bottom-emission type light emitting diode display |
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|---|---|
| CN (1) | CN115732528A (en) |
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2021
- 2021-09-01 CN CN202111019928.0A patent/CN115732528A/en active Pending
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