CN110969959B - an LED display - Google Patents

Abstract

The application discloses LED display screen, LED display screen includes a plurality of array distribution's LED light source, the LED light source includes the LED chip and covers the packaging resin on LED chip surface, wherein, packaging resin's thickness scope is 1mm-3 mm. According to the LED light source, the thickness of the packaging resin is increased, and the large-angle light emitted by the LED light source is further reflected to compress the light emitting angle of the LED light source, so that the light crosstalk among pixels is reduced.

Description

an LED display

technical field

The present application relates to the field of display technology, in particular to an LED display screen.

Background technique

In the existing LED display screen, light-emitting diodes are assembled or packaged together to form a pixel lattice, and each light-emitting diode chip is driven by different voltages to emit light of different brightness and color, so as to realize image display. The LED display has the advantages of high brightness, long life, good performance stability, etc., and is widely used in outdoor advertising. Due to the long viewing distance, although the pixel lattice spacing of the LED display is large, it still does not affect its display effect. In recent years, with the wider application of LED displays, LED displays have also been gradually put into indoor display applications. The viewing distance of indoor display applications is relatively short, which has magnified some of the shortcomings of LED displays, such as viewing particles at close range. The feeling is too strong, the light filling rate is low, the light output is uneven, etc.

In order to solve the above display defects, at present, a diffusion film is added to solve the problems of light filling rate and uneven light output between pixel lattices. Therefore, the light crosstalk between the pixel lattices is avoided, that is, the light emitting diode in a single pixel is incident into adjacent pixels at a large angle, which seriously affects the display effect.

SUMMARY OF THE INVENTION

The main technical problem to be solved by the present application is to provide an LED display screen, which can reduce the light outgoing angle of the LED chip and reduce the light crosstalk between adjacent pixels.

In order to solve the above technical problems, the first technical solution adopted in the present application is to provide an LED display screen, the display screen includes a plurality of LED light sources distributed in an array, and the LED light source includes an LED chip and a package covering the surface of the LED chip. resin, wherein the thickness of the encapsulating resin ranges from 1mm to 3mm.

Wherein, the cut surface of the encapsulating resin along the light-emitting direction of the LED chip is an inverted trapezoid.

Wherein, the cut surface of the encapsulating resin along the light-emitting direction of the LED chip is an inverted arch.

Wherein, the encapsulating resin includes an upper surface and a lower surface, wherein the area ratio of the upper surface and the lower surface is k, wherein 1<k<3.75, preferably 1.5<k<2.5.

Wherein, the encapsulation resin includes light-absorbing particles, wherein the concentration of the light-absorbing particles is 1-200 mol/cm ³ .

Wherein, the light-absorbing particles include at least one of colored glass particles and metal nanoparticles.

Wherein, the LED light source further includes a reflective layer disposed on the outer side of the encapsulating resin and adjacent to the encapsulating resin, and the reflectivity of the reflective layer ranges from 50% to 90%.

Wherein, at least one side of the LED chip is further provided with a black light absorbing layer, and the encapsulating resin covers the LED chip and the black light absorbing layer.

Wherein, a shading frame is arranged between adjacent LED light sources.

Wherein, the side wall of the light-shielding frame relative to the LED light source is coated with an absorption layer or a dispersion layer.

Among them, it includes a diffusing film arranged opposite to the LED light source, and the diffusing film is an integral forming film or a splicing film.

Wherein, different regions of the diffusion film have different diffusion angles to the light emitted by the LED light source.

The beneficial effects of the present application are as follows: the LED display screen provided by the present application includes LED light sources arranged in an array, the LED light sources include LED chips and an encapsulation resin covering the surface of the LED chips, wherein the thickness of the encapsulation resin ranges from 1 mm to 3 mm. The present application further reflects the large-angle light emitted by the LED light source by increasing the thickness of the encapsulation resin, so as to compress the light emission angle of the LED light source, thereby reducing the light crosstalk between pixels.

Description of drawings

1 is a schematic structural diagram of an embodiment of an LED display screen of the present application;

FIG. 2 is a schematic structural diagram of the first embodiment of the LED light source in the LED display screen of the present application;

Figure 3a is a schematic diagram of the divergence angle distribution of the LED light source when the conventional package thickness is 0.3mm;

3b is a schematic diagram of the divergence angle distribution of the LED light source when the package thickness of the present application is 3 mm;

4a is a schematic structural diagram when the shape of the encapsulation resin of the present application is a prism;

4b is a schematic structural diagram when the shape of the encapsulation resin of the present application is a circular truncated table;

5 is a schematic structural diagram of the second embodiment of the LED light source in the LED display screen of the present application;

6 is a schematic structural diagram of a third embodiment of the LED light source in the LED display screen of the present application;

7 is a schematic structural diagram of the third embodiment of the present application when the cut surface of the encapsulation resin along the light-emitting direction of the LED chip is an inverted arch;

8 is a schematic structural diagram of the fourth embodiment of the LED light source in the LED display screen of the present application;

9 is a schematic structural diagram of the fourth embodiment of the present application when the section of the encapsulation resin along the light-emitting direction of the LED chip is an inverted arch;

10 is a schematic diagram of the wavelength change after adding light-absorbing particles to the encapsulating resin in the fourth embodiment of the present application;

FIG. 11 is a schematic structural diagram of adding a black light-absorbing layer to the LED light source in FIG. 8;

FIG. 12 is a schematic structural diagram after adding a black light-absorbing layer to the LED light source in FIG. 9;

13 is a schematic structural diagram of the LED display screen according to the fifth embodiment of the present application;

FIG. 14 is a schematic diagram of the area ratio of the upper surface and the lower surface of the LED display screen of the present application and the light emitting angle distribution of the LED light source.

Detailed ways

This application provides an LED display screen. In order to make the purpose, technical solution and technical effect of this application more clear and clear, the application will be described in further detail below. It should be understood that the specific implementation regulations described here are only used to explain the application, and It is not intended to limit this application.

Example 1

In order to solve the light crosstalk between the LED light sources in the LED display screen and improve the display effect of the display screen, the present application provides an LED display screen, as shown in FIG. 1 , which is a schematic structural diagram of an embodiment of the LED display screen of the present application , the LED display screen 1 includes a plurality of LED light sources 11 arranged in an array.

As shown in FIG. 2 , FIG. 2 is a schematic structural diagram of an embodiment of the LED light source in the LED display screen of the present application. In this embodiment, the LED light source includes an LED chip 111 and an encapsulation resin 112 covering the surface of the LED chip 111 , and a surrounding encapsulation resin. For the reflective layers 113 disposed adjacent to each other, the thickness h of the encapsulating resin 112 ranges from 1 mm to 3 mm. Preferably, the thickness h of the encapsulation resin 112 is 2 mm. Compared with the prior art, in the present application, when the lateral dimension of the LED chip remains unchanged, the thickness of the encapsulation resin 112 is increased by about 10 times, which effectively increases the aspect ratio of the encapsulation resin 112 and thus increases the upper plane of the encapsulation resin 112 The ratio of the size a to the size b of the lower plane makes the large-angle light emitted by the LED chip 111 converge as much as possible on the diffusion film corresponding to the pixel unit through the reflective layer 113 .

Further as shown in Figure 3a and Figure 3b, Figure 3a is a schematic diagram of the divergence angle distribution of the LED light source when the conventional package thickness is 0.3mm. Due to the thin thickness of the packaging resin, there are only very large angles (for example, plus or minus 85°) light rays Therefore, the LED light source can be approximated as a Lambertian light source, and more outgoing light rays are still radiated in a large solid angle space, which easily causes light crosstalk between pixels. As shown in Fig. 3b, Fig. 3b is a schematic diagram of the divergence angle distribution of the LED light source when the package thickness is 3 mm. When the thickness of the encapsulation resin 42 is increased to about 10 times, more large-angle light is reflected by the reflective layer and exits at a small angle, so that the LED The light-emitting angle of the light source is reduced to within 50°.

4a and 4b, the encapsulating resin 112 may be a prismatic or circular truncated structure. FIG. 4a is a schematic structural diagram when the encapsulating resin 112 is in the shape of a prism, and FIG. 4b is a schematic structural diagram when the encapsulating resin 112 is in a circular frustum. When 112 is a prismatic structure, the encapsulating resin 112 includes an upper surface S1 and a lower surface S2, wherein the upper surface S1 corresponds to the light-emitting surface, and the lower surface S2 corresponds to the light-incident surface, wherein the upper surface S1 and the lower surface S2 can be rectangular or square. Preferably, the upper surface S1 and the lower surface S2 are proportional rectangles or squares, and the area of the upper surface S1 must be larger than that of the lower surface S2, so that the cut surface of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is an inverted trapezoid. The area ratio of the upper surface S1 to the lower surface S2 is k, wherein 1<k<3.75, preferably 1.5<k<2.5. When the encapsulating resin 112 has a circular truncated structure, the encapsulating resin 112 includes an upper surface S1 and a lower surface S2, wherein the upper surface S1 corresponds to the light-emitting surface, and the lower surface S2 corresponds to the light-incident surface, wherein the upper surface S1 and the lower surface S2 can be elliptical, round. Preferably, the upper surface S1 and the lower surface S2 are proportional ellipses or circles, and the area of the upper surface S1 must be larger than the area of the lower surface S2, so that the cut surface of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is an inverted trapezoid, wherein The area ratio of the upper surface S1 to the lower surface S2 is k, wherein 1<k<3.75, preferably 1.5<k<2.5. Further, the encapsulation resin 112 may be formed of any transparent resin material, and preferably, the encapsulation resin 112 is an electrically insulating transparent resin.

Further, as shown in FIG. 14 , picture b is a schematic diagram of the illuminance of the LED light source when the area ratio k of the upper surface and the lower surface of the encapsulating resin is 1. At this time, the outgoing light of the LED light source is mainly concentrated in a small angle range. Correspondingly, the illumination range of the LED light source in the corresponding pixel area is too smaller than the pixel area, so that the LED light source has a large unilluminated area at the edge of the corresponding pixel area, resulting in low pixel filling efficiency and strong graininess of the LED display. . Figure c is a schematic diagram of the illuminance of the LED light source when the area ratio k of the upper surface and the lower surface of the encapsulating resin is 3.75. At this time, the outgoing light of the LED light source is relatively uniform. Correspondingly, the illuminance range of the LED light source in the corresponding pixel area is relatively uniform. , so that the edge illuminance and center point illuminance of the LED light source in the corresponding pixel area do not change much, resulting in the LED light source with a large illuminance range of light entering the adjacent pixel area, resulting in serious light crosstalk in the LED display. Figure a is a schematic diagram of the illuminance of the LED light source when the area ratio k of the upper surface to the lower surface of the encapsulating resin is 2. At this time, the emitted illuminance of the LED light source changes relatively smoothly in the corresponding pixel area, and the illuminance in the pixel range is from the central area to the The edge area gradually decreases, and the illuminance of the edge area is 10% of the illuminance of the central area. Considering the superposition of illuminance between adjacent pixel edges, the pixel edge of the LED display screen will not be caused by the LED light source not being illuminated. The pixel filling rate is low and the graininess is strong, and the light crosstalk between adjacent pixels is not too serious, which affects the display effect.

The LED chip 111 is grown on the substrate by a gas phase or liquid phase method. The LED chip 111 can be packaged by a single LED chip, or can be packaged by a plurality of LED chips. When the LED chip 111 is packaged by multiple chips, the LED chip 111 includes: at least one red LED chip, at least one blue LED chip and at least one green LED chip. Preferably, the LED chip 111 includes a red LED chip, a blue LED chip and a green LED chip simultaneously encapsulated in a transparent resin.

Further, the LED light source also includes a reflective layer 113 disposed on the outer side of the encapsulation resin 112 and attached adjacent to the encapsulation resin 112 . The thickness of the reflective layer 113 is the same as the thickness of the encapsulation resin 112 . The joint surface is a reflective surface, and the reflective layer 113 plays a role of reflecting and converging the large-angle light of the LED. The material of the reflective layer 43 is usually one or more of ceramics, metals, resins, etc. The reflectivity of the reflective layer of different materials is different, and the reflectivity of the reflective layer 43 of the present application ranges from 50% to 90%.

Different from the prior art, the LED light source in the LED display screen provided by the present application includes an LED chip and an encapsulation resin covering the surface of the LED chip, wherein the thickness of the encapsulation resin ranges from 1 mm to 3 mm. By increasing the thickness of the encapsulation resin, the present application achieves a high filling rate of light and at the same time compresses the light exit angle of the LED light source, which significantly reduces the light crosstalk between pixels, thereby improving the display effect of the LED display screen.

Embodiment 2

As shown in FIG. 5 , FIG. 5 is a schematic structural diagram of the second embodiment of the LED light source in the LED display screen of the present application. The difference between this embodiment and the first embodiment is that the cut surface of the encapsulating resin 112 along the light emitting direction of the LED chip 111 is an inverted arch. Embodiment 2 The contact surface between the encapsulation resin 112 and the reflective layer 113 is a paraboloid, and the paraboloid structure is more conducive to the convergence and collection of the light emitted by the LED chip 111, and for the LED chip 111 with a small light-emitting area (similar to a point light source), the The parabolic structure can play the role of collimating light.

Different from the prior art, by increasing the thickness of the encapsulating resin, this embodiment achieves a high filling rate of light while compressing the light exit angle of the LED light source, which significantly reduces the light crosstalk between pixels. Different from the first embodiment, this embodiment In the example, the cut surface of the encapsulating resin along the light emitting direction of the light emitting diode chip is an inverted arch, which is more conducive to the convergence and collection of the emitted light, and further improves the display effect of the LED display screen.

Embodiment 3

In any of the above-mentioned embodiments, in order to absorb the incident ambient light and improve the contrast ratio, in this embodiment, a black light-absorbing layer is provided on at least one side of the substrate of the LED chip. As shown in FIG. 6 , FIG. 6 is a schematic structural diagram of the third embodiment of the LED light source in the LED display screen of the present application. The LED light source in this embodiment not only includes the LED chip 111 and the LED chip 111 with a thickness ranging from 1 mm to 3 mm. The encapsulation resin 112 , and the reflective layer 113 disposed adjacent to the encapsulation resin layer 112 . The difference between this embodiment and any of the above embodiments is that a black light absorbing layer 114 is further provided on at least one side of the substrate of the LED chip 111 , and the encapsulating resin 112 covers the LED chip 111 and the black light absorbing layer 114 . Preferably, before the LED chip is encapsulated with resin, a black light absorbing layer 114 is formed on the substrate around the LED chip 111 by a process such as photolithography, evaporation and the like.

In the present application, by setting the black light absorbing layer 114, most of the incident ambient light is absorbed by the black light absorbing layer 114, and the light in the wavelength range of the primary color light emitted by the LED chip 111 is almost totally reflected, which effectively improves the LED display screen. Contrast, improving the display effect. The number of black light absorbing layers 114 is plural, and the plurality of black light absorbing layers 114 are distributed around the LED chip 111 , for example, in a rectangular array or an annular array. In this embodiment, the black light absorbing layer 114 is square, which improves the overall light absorbing effect. Of course, in other embodiments, the black light absorbing layer 114 may also be in a circle or polygon or other shapes, as long as the light absorbing effect of the black light absorbing layer 114 can be satisfied.

Optionally, the section of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is an inverted trapezoid or an inverted arch. When the section of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is an inverted arch, the schematic diagram of the structure of the LED light source is shown in FIG. 7 . , the parabolic structure of the encapsulation resin 112 is more conducive to the collection of light emitted by the LED chip 111, and for the LED chip 111 with a small light-emitting area (similar to a point light source), the parabolic structure can play the role of collimating light.

Different from the prior art, the present embodiment increases the thickness of the encapsulation resin, thereby increasing the ratio of the upper plane size to the lower plane size of the encapsulation resin. That is, under the condition that the lateral size of the LED chip remains unchanged, the thickness of the encapsulation resin is about 10 times higher than that of the existing encapsulation structure, which effectively improves the aspect ratio of the encapsulation resin, so that the light emitted from the LED chip is greatly concentrated to the corresponding pixel unit. on the diffusion membrane. Different from any of the above embodiments, in this embodiment, by adding a black light absorbing layer to the LED light source, the incident ambient light is effectively absorbed and the contrast ratio is improved.

Embodiment 4

In any of the above-mentioned embodiments, in order to make the LED light source have a narrower wavelength range, in this embodiment, light-absorbing particles are added to the encapsulating resin. As shown in FIG. 8 , FIG. 8 is a schematic structural diagram of the fourth embodiment of the LED light source in the display screen of the present application. In this embodiment, the LED light source includes an LED chip 111 and an encapsulation resin 112 covering the surface of the LED chip 111 , wherein, The thickness of the encapsulating resin 112 ranges from 1 mm to 3 mm. The reflective layer 113 is disposed outside the encapsulating resin 112 and is adjacent to the encapsulating resin 112 . Optionally, the cut surface of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is trapezoidal or inverted arch. When the cut surface of the encapsulating resin 112 along the light-emitting direction of the LED chip 111 is an inverted arch, the schematic diagram of the structure of the LED light source is shown in FIG. 9 .

In this embodiment, in order to make the LED light source have a narrower wavelength range, the encapsulating resin 111 includes light absorbing particles, and the light absorbing particles can absorb light of certain wavelengths but not other wavelengths. The choice is related to the wavelength of the absorbed light, which can be calculated via Bill Lambert's law. In this embodiment, the light-absorbing particles are preferably at least one of colored glass particles and metal nanoparticles, wherein the concentration of the light-absorbing particles is 1-200 mol/cm ³ .

As shown in Figure 10, Figure 10 is a schematic diagram of the wavelength change after adding light absorbing particles to the encapsulating resin, wherein the dotted line represents the wavelength schematic diagram of the encapsulating resin without adding the light absorbing particles, and the solid line represents the encapsulating resin after adding the light absorbing particles. After the light-absorbing particles, the light-absorbing particles only absorb the narrow-band spectrum corresponding to the emitted light of the LED chip, and do not absorb the main emission spectrum of the emitted light of the LED chip, so that the emitted light of the LED chip 111 has a narrower wavelength range, which is helpful to expand the LED display. color gamut of the screen.

Further, in this embodiment, a black light absorbing layer 114 may be provided on at least one side of the LED chip 111 , and the encapsulating resin 112 covers the LED chip 111 and the black light absorbing layer 114 , as shown in FIG. 11 and FIG. 12 , and FIG. 11 8 is a schematic diagram of the structure after adding a black light absorbing layer, and FIG. 12 is a schematic structural diagram after adding a black light absorbing layer in FIG. , and the light in the wavelength range of the primary color light emitted by the LED chip 111 is almost totally reflected, which effectively improves the contrast of the LED display screen and improves the display effect. .

Different from the prior art, the LED light source provided in the present application includes: an LED chip and an encapsulation resin covering the surface of the LED chip, wherein the thickness of the encapsulation resin ranges from 1 mm to 3 mm. By increasing the thickness of the encapsulation resin, the present application achieves a high filling rate of light and at the same time compresses the light exit angle of the LED light source, thereby significantly reducing the light crosstalk between pixels. Different from any of the above embodiments, the encapsulation resin in this embodiment also includes light absorbing particles, which make the emitted light of the LED light source have a narrower wavelength range and help to expand the color gamut of the LED display screen.

Embodiment 5

In any of the above-mentioned embodiments, in order to further isolate the crosstalk light between adjacent LED light sources, in this embodiment, a light-shielding frame is arranged between adjacent LED light sources. As shown in FIG. 13 , FIG. 13 is a schematic structural diagram of the fifth embodiment of the LED light source in the LED display screen of the present application. In this embodiment, the LED display screen 13 includes LED light sources 131 arranged in an array, and the diffusing film 133 is disposed opposite to the LED light sources 131. The diffusing film 133 can be an integrally formed film with an area equivalent to the LED display screen, or can be formed by a plurality of The diffusion film spliced together, in which the diffusion angle of the diffusion film 133 to the light emitted by the LED light source can also be distributed regionally. For example, the diffusion film 133 has a larger diffusion angle in the area corresponding to the luminous center of the LED light source, and in the area corresponding to the luminous edge of the LED light source. The diffusion angle is small to achieve a more optimized illuminance distribution. A light-shielding frame 132 is arranged between adjacent LED light sources 131 , and the light-shielding frame 132 is arranged between the array of LED light sources 131 and the diffusion film 132 .

The specific structure of the LED light source 131 has been described in detail with reference to the drawings in the first to fourth embodiments above and the related text description, and will not be repeated here.

The light-shielding frame 132 is placed between the LED light source array and the diffusion film, which can block the crosstalk light between adjacent LED light sources 131. The material of the light-shielding frame 132 is plastic such as polymethyl methacrylate, polyacrylonitrile, polypropylene, polychlorinated ethylene, polyvinyl chloride, etc., and can selectively coat an absorption layer on the side wall of the light-shielding frame 132 opposite to the LED light source 131, or coat a scattering layer such as titanium dioxide, barium sulfate and other white scattering particles, for each pixel The light in the pixel is scattered, or a metal reflective layer or a diffuse reflection layer can be coated to reflect the light in each pixel.

Different from any of the above-mentioned embodiments, in the LED display screen provided by this embodiment, a light-shielding frame is arranged between adjacent LED light sources, which further blocks the crosstalk light of adjacent LED light sources, significantly reduces the light crosstalk between pixels, and further improves the performance of the LED display screen. The display effect of the LED display.

The above descriptions are only the embodiments of the present application, and are not intended to limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related The technical field is similarly included in the scope of patent protection of this application.

Claims (11)

1. An LED display screen, characterized in that the LED display screen comprises a plurality of LED light sources distributed in an array, and the LED light sources comprise LED chips and an encapsulation resin covering the surface of the LED chips, wherein the encapsulation The thickness of the resin is in the range of 1mm-3mm, and the encapsulation resin includes an upper surface and a lower surface, wherein the area ratio of the upper surface and the lower surface is k, where 1<k<3.75, so as to compress the light emitted by the LED light source. For the exit angle, the encapsulating resin includes light-absorbing particles, wherein the concentration of the light-absorbing particles is 1-200 mol/cm ³ , so that the light emitted from the LED light source has a narrower wavelength range. 2 . The LED display screen according to claim 1 , wherein a cut surface of the encapsulation resin along the light-emitting direction of the LED chip is an inverted trapezoid. 3 . 3 . The LED display screen according to claim 1 , wherein a cut surface of the encapsulation resin along the light-emitting direction of the LED chip is an inverted arch. 4 . 4 . The LED display screen according to claim 1 , wherein the area ratio of the upper surface and the lower surface is k, wherein 1.5<k<2.5. 5 . 5 . The LED display screen according to claim 1 , wherein the light absorbing particles comprise at least one of colored glass particles and metal nanoparticles. 6 . 6. The LED display screen according to any one of claims 1 to 4, wherein the LED light source further comprises a reflective layer disposed outside the encapsulation resin and adjacent to the encapsulation resin, wherein The reflectivity of the reflective layer ranges from 50% to 90%. 7. The LED display screen according to any one of claims 1 to 4, wherein a black light absorbing layer is further provided on the substrate on at least one side of the LED chip, and the encapsulating resin covers the LED chip and all the LED chips. the black light-absorbing layer. 8 . The LED display screen according to claim 1 , wherein a light-shielding frame is arranged between the adjacent LED light sources. 9 . 9 . The LED display screen according to claim 8 , wherein the side wall of the light shielding frame relative to the LED light source is coated with a light absorption layer, a scattering layer or a reflection layer. 10 . 10. The LED display screen according to claim 8, characterized in that it comprises a diffusing film disposed opposite to the LED light source, and the diffusing film is an integral molding film or a splicing film. 11 . The LED display screen according to claim 10 , wherein different regions of the diffusion film have different diffusion angles to the light emitted by the LED light source. 12 .

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