Small-spacing LED display screen

Abstract

The invention relates to a small-spacing LED display screen. The small-spacing LED display screen comprises a circuit substrate; the plurality of light-emitting chips are arranged on the circuit substrate; the dimming layer comprises a light-transmitting box body, dispersion liquid arranged in the light-transmitting box body and temperature-sensitive particles dispersed in the dispersion liquid; the heat absorption layer is arranged on the surface, facing the light-emitting chips, of the dimming layer, the heat absorption layer comprises a plurality of sub heat absorption pieces, and the distance between the centers of every two adjacent sub heat absorption pieces is equal to the distance between the centers of every two adjacent light-emitting chips; the heat absorption layer can regulate and control the temperature of the dimming layer so that part of the temperature-sensitive particles can be accumulated around each light-emitting chip to form a temperature-sensitive particle group, and the temperature-sensitive particle group can control the angle of light emitted by the light-emitting chips.

Description

Technical Field

[0001] The present application relates to the field of LED display technology, and in particular to a small-pitch LED display screen. Background Art

[0002] With the continuous improvement of indoor display application technology, the currently used projection / DLP / LCD / PDP and other display application products can no longer fully meet the market application needs. There are still some defects in various aspects that prevent them from breaking through the development of technology. The LED full-color display screen overcomes many of the defects of the above products and has become the first choice for indoor and outdoor large-screen displays, such as command centers, outdoor advertising screens, conference centers and other occasions.

[0003] Usually, LED display screens are seamlessly spliced ​​into large-sized display screens by a certain number of small-sized display screen modules. At present, the minimum dot pitch of LED display screens is about 1mm, and the market has a broad demand for LED display screens with smaller dot pitches. Smaller dot pitches will make the picture clearer. However, since LED has a larger light-emitting angle, light crosstalk will occur between adjacent light-emitting chips, affecting the light-emitting effect of the light-emitting chips.

[0004] The current measure to solve the optical crosstalk is to form a barrier between adjacent light-emitting chips to solve the problem of optical crosstalk. However, since the minimum dot pitch of the LED display is very small, the space left for the barrier is limited, which brings challenges to the manufacturing process of small-pitch display screens.

[0005] Therefore, it is necessary to provide an LED display screen that can solve the optical crosstalk problem of a display screen with a small pitch and make the manufacturing process simpler. Summary of the invention

[0006] The present application provides a small-pitch LED display screen, which can solve the problem of process difficulty of small-pitch display screens.

[0007] A small-pitch LED display screen, comprising: Circuit substrate; A plurality of light-emitting chips are arranged on the circuit substrate; The dimming layer includes a light-transmitting box body, a dispersion disposed in the light-transmitting box body, and temperature-sensitive particles dispersed in the dispersion; and A heat absorption layer is arranged on the surface of the dimming layer facing the light-emitting chip, the heat absorption layer includes a plurality of sub-heat absorption sheets, the distance between the centers of two adjacent sub-heat absorption sheets is equal to the distance between the centers of two adjacent light-emitting chips, and the heat absorption layer is used to regulate the temperature of the dimming layer so that the temperature-sensitive particles can accumulate into temperature-sensitive particle clusters within a preset temperature range, and the temperature-sensitive particle clusters can control the angle of light emitted by the light-emitting chip.

[0008] In one embodiment of the present application, the light-emitting chip includes a red light-emitting chip, a green light-emitting chip and a blue light-emitting chip, and the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip are arranged in an array.

[0009] In one embodiment of the present application, each of the sub-heat absorbing sheets is in a strip shape, and a plurality of the sub-heat absorbing sheets are arranged in a grid shape.

[0010] In one embodiment of the present application, each sub-heat absorbing sheet is ring-shaped.

[0011] In one embodiment of the present application, the light emitting windows formed by the temperature-sensitive particle cluster corresponding to the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip have different shapes or sizes.

[0012] In one embodiment of the present application, the heat absorption layer is made of a phase change material or a carbon nanotube film.

[0013] In one embodiment of the present application, the thickness of the light-transmitting box body is between 1.8 and 3.2 um.

[0014] In one embodiment of the present application, the circuit substrate includes a first surface and a second surface, the first surface is provided with a pad for connecting to the light-emitting chip, and the second surface has a connecting portion for connecting to the driving chip.

[0015] In one embodiment of the present application, a plurality of light-emitting chips form a light-emitting area, and the circuit substrate is further provided with support columns located around the light-emitting area, a supporting platform is provided on the support columns, and the dimming layer is provided on the supporting platform.

[0016] In one embodiment of the present application, the size of the light-emitting chip is no greater than 100 microns×200 microns.

[0017] In summary, the present application includes at least one of the following beneficial technical effects: 1. By arranging a dimming layer and a heat absorption layer in the light emitting direction of the light emitting chip, the heat absorption layer is used to absorb the heat emitted by the light emitting chip and conduct it to the dimming layer, so that the temperature of the dimming layer is within a preset temperature range, so that part of the temperature-sensitive particles can absorb heat and accumulate into a temperature-sensitive particle cluster around each light emitting chip, and the temperature-sensitive particle cluster can control the angle of the light emitted by the light emitting chip. Therefore, the problem of light crosstalk can be overcome without setting a retaining wall between the light emitting chips, thereby further improving the density of the light emitting chips, that is, reducing the spacing between the light emitting chips. The small-pitch LED display provided by the present application simplifies the production process of the small-pitch LED display because there is no need to set a retaining wall between adjacent light emitting chips.

[0018] 2. The small-pitch LED display provided in the present application controls part of the temperature-sensitive particles to accumulate into a temperature-sensitive particle cluster around each light-emitting chip through a heat-absorbing layer, and the temperature-sensitive particles directly above the light-emitting direction of the light-emitting chip can scatter the light and thus achieve a uniform light effect, so there is no need to set a diffuser.

[0019] 3. The light emitting windows corresponding to the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip formed by the temperature-sensitive particle cluster have different shapes or sizes, so that the size of the cluster of temperature-sensitive particles accumulated can be controlled according to the color of the light-emitting chip by absorbing different amounts of heat to reasonably adjust the size of the light emitting area of ​​the light-emitting chip. Light emitting windows of different shapes and sizes can adjust the luminous intensity of the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip, so that the small-pitch display screen of the present invention has a higher color gamut. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a cross-sectional view of a small-pitch LED display screen provided in the first embodiment of the present application; Figure 2 yes Figure 1 The structural diagram of the small-pitch LED display provided; Figure 3 yes Figure 1 The working status cross-sectional view of the small pitch LED display provided; Figure 4 This is a cross-sectional view of a small-pitch LED display screen provided in the second embodiment of the present application.

[0021] Explanation of the reference numerals: 10, circuit substrate; 20, light emitting chip; 30, dimming layer; 40, heat absorption layer; 50, support column; 32, light-transmitting box body; 34, temperature-sensitive particles; 36, temperature-sensitive particle cluster; 38, light-emitting window; 42, sub-heat absorption sheet; 52, supporting platform. DETAILED DESCRIPTION

[0022] The following is combined with Figure 1-4 The small-pitch LED display screen provided in this application is further described in detail.

[0023] See also Figure 1-3 , which is a small-pitch LED display screen provided in the first embodiment of the present application, includes: a circuit substrate 10, a plurality of light-emitting chips 20, a dimming layer 30, a heat absorption layer 40 and a support column 50.

[0024] The circuit substrate 10 is a PCB board. In this embodiment, the circuit substrate 10 includes a first surface and a second surface. The first surface is provided with a pad for connecting with the light emitting chip 20; the second surface has a connecting portion (not shown) for connecting with the driving chip.

[0025] A plurality of light emitting chips 20 are disposed on the circuit substrate 10 and electrically connected to the circuit substrate 10. In the present embodiment, the light emitting chips 20 include a red light emitting chip 20, a green light emitting chip 20, and a blue light emitting chip 20, and the red light emitting chip 20, the green light emitting chip 20, and the blue light emitting chip 20 are arranged in an array. Of course, it can be understood that the color of the light emitting chip 20 may not be limited.

[0026] The light emitting chip 20 may be an LED or a mini-LED. In the present application, the light emitting chip 20 is a mini-LED, and the size of the light emitting chip 20 is not greater than 100 microns×200 microns, so that the density of the light emitting chip on the circuit substrate 10 can be further improved.

[0027] The dimming layer 30 includes a light-transmitting box body 32 , a dispersion liquid (not shown) disposed in the light-transmitting box body 32 , and temperature-sensitive particles 34 dispersed in the dispersion liquid.

[0028] The temperature-sensitive particles 34 may be polycaprolactone-polyethylene glycol-polycaprolactone (PCL-PEG6000-PCL), N-isopropylacrylamide (NIPAM) or cyclodextrin (PCL1000-PEG6000-PCL1000-β-CD); specifically, the temperature-sensitive particles 34 may also include a hydrophilic group and a hydrophobic group.

[0029] In other implementations, a thin reflective layer may be further formed on the surface of the temperature-sensitive particles 34 to better scatter light.

[0030] The material of the light-transmitting box body 32 includes silicone resin or epoxy resin.

[0031] In the present application, the temperature-sensitive particles 34 made of N-isopropylacrylamide material can be prepared in the following manner: the first step is to dissolve chitosan (CS) in an acetic acid solution, then add the monomer N-isopropylacrylamide (NIPAM) and stir evenly, adjust the obtained solution to a certain temperature, then add cerium ammonium nitrate (CAN) solution as an initiator, and then pass nitrogen for protection. After a period of reaction, an organic solvent is added to the mixed solution for precipitation to obtain a crude product, and then the fine product is obtained by extraction, and then the final product is obtained after drying, which is the CS-PNIPAM temperature-sensitive particle 34.

[0032] The amount ratio of the chitosan, monomer N-isopropylacrylamide, ammonium cerium nitrate and acetic acid solution is 5-10g:5-2g:1g:20-50mL; the volume concentration of the acetic acid solution is 2%-5%; the temperature is adjusted to 40-50°C; and the reaction period is 24-48h.

[0033] In the above steps, the organic solution is any one of acetone, dichloromethane, chloroform, N-N-dimethylacetamide, ethyl acetate, or a composite solution of any number of dihydrofuran in any proportion; the volume ratio of the mixed solution to the organic solvent is 1:5-15, and the drying temperature is 25-40°C.

[0034] In the present application, the dispersion can be prepared by: dissolving essential oil in ethanol solution to obtain a mixed solution A; and then dissolving the prepared temperature-sensitive particles 34 in distilled water to prepare a dispersion of the temperature-sensitive particles 34 with a certain mass concentration.

[0035] Of course, the present application only provides a possible method for preparing the temperature-sensitive ions and the dispersion to obtain the desired dimming layer 30 . In other embodiments, the temperature-sensitive particles 34 and the dispersion may also be prepared in other ways.

[0036] The transparent box body 32 included in the dimming layer 30 can be about 1.8~3.2um thick. Within this thickness range, the dimming layer 30 has the highest utilization rate of light and can also ensure the thickness of the display screen is thin. When in a low temperature or normal temperature environment, the temperature-sensitive particles 34 are in a scattered light state, and the transmittance is as high as 90%. Figure 1 Status shown.

[0037] The temperature-sensitive particles 34 and the dispersion liquid can be filled into the light-transmitting box 32 by injection.

[0038] When the light-transmitting box body 32 is in an environment of about 35 degrees Celsius, the temperature-sensitive particles 34 in the light-transmitting box body 32 are aggregated in response to the temperature. In this embodiment, the temperature of the preset area can be modulated to meet the accumulation temperature of the temperature-sensitive particles 34, and the accumulated temperature-sensitive particle clusters 34 can achieve the effect of a retaining wall, such as Figure 3 In the state shown, the temperature-sensitive particles 34 far away from the heat absorption layer 40, that is, the temperature-sensitive particles 34 in the area facing the light-emitting chip 20, become sparse. This part of the temperature-sensitive particles 34 is less affected by temperature and still plays a role in scattering light.

[0039] See also Figure 2 The heat absorption layer 40 is arranged on the surface of the dimming layer 30 facing the light emitting chip 20. The heat absorption layer 40 includes a plurality of sub-heat absorption sheets 42. The center of the area enclosed by the sub-heat absorption sheets 42 coincides with the center of the corresponding light emitting chip 20. The heat absorption layer 40 is used to regulate the temperature of the dimming layer 30 so that the temperature-sensitive particles 34 can accumulate into temperature-sensitive particle clusters 36 within a preset temperature range. The temperature-sensitive particle clusters 36 can control the angle of the light emitted by the light emitting chip 20, avoid part of the light beam emitted by the light emitting chip 20 from being emitted from the adjacent light emitting area, and solve the problem of light crosstalk.

[0040] In this embodiment, each sub-heat absorbing sheet 42 is strip-shaped, and a plurality of sub-heat absorbing sheets 42 are arranged in a grid. In other embodiments, each sub-heat absorbing sheet 42 may also be ring-shaped. The ring may be a circular ring, a square ring, a triangle, a trapezoid, a polygon, a regular or irregular shape, etc.

[0041] In this embodiment, the material of the heat absorption layer 40 is a phase change material or a carbon nanotube film. The phase change material or the carbon nanotube film can quickly absorb the heat emitted by the LED and transfer it to the dimming layer 30. When the temperature-sensitive particles 34 in the light-transmitting box body 32 are heated, they will quickly accumulate into temperature-sensitive particle clusters 36. Then, the light emitted by the light-emitting chip 20 can only be emitted from between the light-emitting windows 38 formed by two adjacent temperature-sensitive particle clusters 36. Thus, the temperature-sensitive particle clusters 36 can achieve the control of the direction of the light emitted by the light-emitting chip 20. The larger the sub-heat absorption sheet 42 is, the more heat it can absorb, and the size of the temperature-sensitive particle clusters 36 formed by the temperature-sensitive particles 34 will also increase accordingly. Therefore, the width of the sub-heat absorption sheet 42 can be appropriately adjusted to achieve a better light crosstalk prevention effect.

[0042] In this embodiment, a plurality of light-emitting chips 20 form a light-emitting area, a support column 50 is arranged on the circuit substrate 10 and is located around the light-emitting area, a supporting platform 52 is arranged on the support column 50, and a dimming layer 30 is arranged on the supporting platform 52. In this way, it can be ensured that the dimming layer 30 is stably arranged in the light emitting direction of the light-emitting chip 20.

[0043] The temperature response interval of the dimming layer 30 is between 30 and 40 degrees, preferably within the temperature range of 35 degrees. In other embodiments, a plurality of temperature sensors may be provided on the surface of the dimming layer 30 facing the light emitting chip 20, and the temperature of the dimming layer 30 may be monitored in real time by the temperature sensors, and the temperature of the dimming layer 30 may be adjusted by the heat dissipation module, so that the temperature-sensitive particles 34 can exert their performance to a greater extent.

[0044] In other embodiments, in order to further achieve the light uniformity effect of the display screen, a diffusion film may be further provided in the light emitting direction of the dimming layer 30 .

[0045] See also Figure 4 , which is a small-pitch LED display provided in the second embodiment of the present application. The small-pitch LED display provided in the second embodiment is basically the same as the small-pitch LED display provided in the first embodiment. The difference is that, in this embodiment, the light emitting windows 38 formed by the temperature-sensitive particle clusters 36 corresponding to the red light-emitting chips 20, the green light-emitting chips 20 and the blue light-emitting chips 20 have different shapes or sizes.

[0046] For example, the size of the sub-heat absorbing sheet 42 can be adjusted so that the sub-heat absorbing sheet 42 can control the size of the temperature-sensitive particle cluster 36 , thereby achieving the adjustment of the light exit window 38 .

[0047] Light exit windows 38 of different shapes and sizes can adjust the luminous intensity of the red light emitting chip 20 , the green light emitting chip 20 , and the blue light emitting chip, so that the small pitch display screen of the present invention has a higher color gamut.

[0048] In summary, the present application sets a dimming layer 30 and a heat absorption layer 40 in the light emitting direction of the light emitting chip 20. The heat absorption layer 40 is used to absorb the heat emitted by the light emitting chip 20 and conduct it to the dimming layer 30, so that the temperature of the dimming layer 30 is within a preset temperature range. In this way, some of the temperature-sensitive particles 34 can absorb heat and accumulate into temperature-sensitive particle clusters 36 around each light emitting chip 20. The temperature-sensitive particle clusters 36 can control the angle of the light emitted by the light emitting chip 20. Therefore, the effect of optical crosstalk can be achieved without setting a baffle wall between the light emitting chips 20. The present application does not need to set a baffle wall between the light emitting chips, so the process is simpler.

[0049] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A small pitch LED display screen, characterized in that: include: Circuit substrate (10); A plurality of light-emitting chips (20) are arranged on the circuit substrate (10) and are electrically connected to the circuit substrate (10); The light-adjusting layer (30) comprises a light-transmitting box body (32), a dispersion liquid disposed in the light-transmitting box body (32), and temperature-sensitive particles (34) dispersed in the dispersion liquid; and A heat absorption layer (40) is arranged on a surface of the dimming layer (30) facing the light emitting chip (20), the heat absorption layer (40) comprises a plurality of sub-heat absorption sheets (42), the distance between the centers of two adjacent sub-heat absorption sheets (42) is equal to the distance between the centers of two adjacent light emitting chips (20), the heat absorption layer (40) can adjust the temperature of the dimming layer (30) so that part of the temperature sensitive particles (34) can be accumulated around each light emitting chip (20) to form a temperature sensitive particle cluster (34), and the temperature sensitive particle cluster (34) can control the angle of light emitted by the light emitting chip (20).

2. A small pitch LED display screen according to claim 1, characterized in that: The light-emitting chip (20) comprises a red light-emitting chip, a green light-emitting chip and a blue light-emitting chip, and the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip are arranged in an array.

3. A small pitch LED display screen according to claim 2, characterized in that: Each of the sub-heat absorbing sheets (42) is in a strip shape, and a plurality of the sub-heat absorbing sheets (42) are arranged in a grid shape.

4. The small pitch LED display screen according to claim 2, characterized in that: Each sub-heat absorbing sheet (42) is ring-shaped.

5. A small pitch LED display screen according to claim 3 or 4, characterized in that: The light exit windows (38) formed by the temperature-sensitive particle cluster (34) and corresponding to the red light-emitting chip, the green light-emitting chip and the blue light-emitting chip have different shapes or sizes.

6. The small pitch LED display screen according to claim 1, characterized in that: The heat absorption layer (40) is made of a phase change material or a carbon nanotube film.

7. The small pitch LED display screen according to claim 1, characterized in that: The thickness of the light-transmitting box body (32) is between 1.8 and 3.2 um.

8. The small pitch LED display screen according to claim 1, characterized in that: The circuit substrate (10) comprises a first surface and a second surface, the first surface being provided with a solder pad for connecting to the light-emitting chip (20), and the second surface having a connecting portion for connecting to a driving chip.

9. The small pitch LED display screen according to claim 1, characterized in that: A plurality of light-emitting chips (20) form a light-emitting area. The circuit substrate (10) is also provided with a support column (50) located around the light-emitting area. A carrier platform (52) is provided on the support column (50). The dimming layer (30) is provided on the carrier platform (52).

10. A small pitch LED display according to any one of claims 1 to 9, characterized in that: The size of the light-emitting chip (20) is no greater than 100 micrometers×200 micrometers.

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