Backlight module and direct type LED backlight source display screen

Abstract

The invention relates to a backlight module which comprises a diffusion plate with a PS material as a base material. The glass fiber aerogel heat insulation sheet is positioned on one side of the diffusion plate; the LED lamp panel is located on the side face, back on to the diffusion plate, of the glass fiber aerogel heat insulation sheet; the side face, facing the glass fiber aerogel heat insulation sheet, of the diffusion plate is a light incidence face, and the distance between the LED lamp panel and the light incidence face ranges from 4.065 mm to 4.637 mm. Wherein the thickness of the glass fiber aerogel heat insulation sheet ranges from 1.065 mm to 3.637 mm. The characteristics of good heat insulation performance, high porosity, low density, good heat insulation performance and the like of the silicon dioxide aerogel are utilized, the heat conductivity of the heat insulation material is effectively reduced, the heat insulation capacity is improved, and meanwhile the weight of a backlight system can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of LED display screens, and in particular to a backlight module and a direct-type LED backlight display screen. Background Art

[0002] The mainstream display technology in the current market is LED display technology, which, as the most important flat panel display technology, drives the continuous updating and upgrading of flat panel display technology.

[0003] At present, LED display is mainly used in LCD TV. With the popularization of TV, ultra-thin and intelligent will become the inevitable development trend of LCD TV. The traditional direct-type backlight source is located at the bottom of the module, which has good brightness and uniformity. However, the surface of LED lamp beads is seriously heated. The base material of the diffusion plate is usually made of PS material. Figure 1 As shown, if the light mixing distance between the LED light board and the diffuser is reduced, the diffuser is prone to warping and aging quickly. This requires increasing the distance between the LED lamp beads and the diffuser so that the light mixing distance is not less than 12 mm, which increases the thickness of the display and is inconsistent with modern applications requiring thinness, lightness and aesthetics.

[0004] The polymer extrusion technology is used to prepare the three-layer diffusion plate, in which the middle layer is the quantum dot layer, and the upper and lower layers are the diffusion layers. The diffusion layer includes a light diffuser and silica aerogel particles. The thermal insulation performance is used to solve the problem of poor thermal stability of the quantum dot diffusion plate. Among them, the silica light-collecting aerogel composite plate uses the ultra-low density of silica aerogel to solve the sedimentation problem of the particle-filled light-collecting composite plate. Glass is used as the base material of the diffusion plate, and the diffusion effect is achieved by superimposing different refractive indices. The glass diffusion plate has good diffusion effect, good thermal insulation effect and high heat resistance, and can be directly used above the LED circuit without spacing.

[0005] The technical problem is that adding silica aerogel to polymers can increase the thermal stability of polymers, but the surface temperature of LED lamp beads exceeds 120°C, and the polymer is easily damaged after reducing the mixing distance. The fragility and weight of glass substrates limit their use as diffusion plate materials, which not only increases the weight of display devices, but also makes assembly and transportation requirements more stringent. Summary of the invention

[0006] The object of the present invention is to provide a backlight module and a direct-type LED backlight display screen that can reduce the light mixing distance and thus reduce the thickness of the display screen, which is specifically achieved by the following technical solutions: A backlight module: It includes a diffuser plate with PS material as the base material; a glass fiber aerogel insulation sheet located on one side of the diffuser plate; and an LED light board located on the side of the glass fiber aerogel insulation sheet facing away from the diffuser plate; the side of the diffuser plate facing the glass fiber aerogel insulation sheet is the light incident surface, and the distance between the LED light board and the light incident surface is 4.065mm-4.637mm; wherein the thickness of the glass fiber aerogel insulation sheet is 1.065mm-3.637mm.

[0007] The backlight module is further designed to use glass fiber as a base material and compound silicon dioxide aerogel to prepare the glass fiber aerogel thermal insulation sheet.

[0008] The backlight module is further designed in that: the glass fiber aerogel insulation sheet is adhered to the light incident surface of the diffusion plate by UV glue or thermosetting glue, and there is an air layer of 1mm-3mm between the glass fiber aerogel insulation sheet and the LED light board.

[0009] The backlight module is further designed in that: the glass fiber aerogel insulation sheet is placed on the LED light board, and the distance between the glass fiber aerogel insulation sheet and the light incident surface is an air layer of 1mm-3mm.

[0010] A direct-lit LED backlight display screen adopts any one of the aforementioned backlight modules.

[0011] Compared with the prior art, the present invention has the following beneficial effects: By utilizing the characteristics of silica aerogel such as good thermal insulation performance, high porosity, low density and good thermal insulation performance, the thermal conductivity of the insulation material can be effectively reduced, the thermal insulation capacity can be improved, and the weight of the backlight system can be reduced.

[0012] Glass fiber aerogel thermal insulation sheet is prepared by supercritical drying process with glass fiber as the base material and composite silica aerogel. It has the characteristics of low thermal conductivity, strong hydrophobicity, excellent fire retardant properties, etc., and can isolate the diffusion plate from damage by high-temperature lamp beads.

[0013] Adding a heat-insulating layer between the LED lamp beads and the diffusion plate can significantly reduce the light mixing distance and reduce the thickness of the display device. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 Heat deflection temperature data for three types of diffusers made from polystyrene substrates.

[0014] Figure 2 Data sheet of prepared glass fiber aerogel thermal insulation sheet.

[0015] Figure 3 Brightness test diagram.

[0016] Figure 4 Schematic diagram of the product structure of the control example and the embodiment.

[0017] Figure 5 Example Data Table.

[0018] Figure 6 Surface image of the diffusion plate after the experiments of Control Group 1 and Example 1. DETAILED DESCRIPTION

[0019] The present invention is further described below with reference to the accompanying drawings and embodiments: A backlight module as shown in the figure: includes a diffuser plate; a glass fiber aerogel insulation sheet located on one side of the diffuser plate; and an LED light board located on a side of the glass fiber aerogel insulation sheet facing away from the diffuser plate; the side of the diffuser plate facing the glass fiber aerogel insulation sheet is a light incident surface, and the distance between the LED light board and the light incident surface is 4.065mm-4.637mm; wherein the thickness of the glass fiber aerogel insulation sheet is 1.065mm-3.637mm.

[0020] The glass fiber aerogel thermal insulation sheet is prepared by taking glass fiber as a base material and compounding silicon dioxide aerogel.

[0021] Specifically, the preparation of glass fiber glass fiber aerogel insulation sheet: silica aerogel matrix: 40-50wt%. Glass fiber: 10-35wt%, the rest is adhesive. The average diameter of the glass fiber: 10-20μm, preferably 10-16μm. Silica aerogel matrix: tetraethoxysilane (TEOS), methyltrimethoxysilane (MTMS), hexamethyldisiloxane (HMDSO), tetraethyl orthosilicate (TEOS), methyl orthosilicate (TMOS), ethyltrimethoxysilane (ETMS), propyltriethoxysilane (PTES) and one or more. Aerogel particles 100-300μm.

[0022] The adhesive includes one or more of silicone adhesive, siloxane emulsion, acrylic adhesive, fumed silica or silicone gel. Preparation process: 1) One or more silica aerogel matrices are dissolved in ethanol in proportion (40% hexamethyldisiloxane, 10% tetraethoxysilane), an appropriate amount of acid catalyst (0.1 M hydrochloric acid) is added, the temperature is controlled at 50-60°C, and stirred for 30-40 minutes to form a uniform sol. 2) Fibers and adhesives (40% glass fiber, 10% adhesive) are added to the sol, and lightly stirred to ensure that the fibers are evenly distributed to form a stable dispersion. 3) The dispersion is poured into a mold, sealed and kept at room temperature to allow it to gel and age for 24 hours. 4) The aged gel material is placed in a supercritical CO2 drying device, first soaked with ethanol, and then replaced with liquid CO2 at 4-8°C to gradually reach supercritical drying conditions to prevent gel collapse. After drying, a glass fiber aerogel insulation sheet is obtained.

[0023] Prepared Figure 2 It should be emphasized that the glass fiber aerogel insulation sheets belong to the prior art known in the art. This patent application describes the preparation process of the glass fiber aerogel insulation sheets, and aims to clarify the selection of the existing glass fiber aerogel insulation sheets to form a specific structural relationship, and it is not a creative improvement of the glass fiber aerogel insulation sheets themselves.

[0024] The diffusion plate in the embodiment has a thickness of 1-3 mm, preferably 1.5 mm, a haze of >99%, and a transmittance of 20-60%, preferably 25-35%.

[0025] Combination Figure 4 As shown, the glass fiber aerogel insulation sheet is attached to the light incident surface of the diffuser plate using UV glue or thermosetting glue, and there is a 1mm-3mm air layer between the glass fiber aerogel insulation sheet and the LED light board. This type of implementation forms a structural relationship (d) between the glass fiber aerogel insulation sheet, the diffuser plate, and the LED light board.

[0026] The glass fiber aerogel insulation sheet is placed on the LED light board, and the distance between the glass fiber aerogel insulation sheet and the light incident surface is 1mm-3mm of air layer. This embodiment forms a structural relationship (c) between the glass fiber aerogel insulation sheet, the diffusion plate, and the LED light board.

[0027] As a control, no glass fiber aerogel insulation sheet is set between the diffuser plate and the LED light board, and only an air layer is retained to form a structural relationship (a); the glass fiber aerogel insulation sheet, the diffuser plate, and the LED light board are bonded together to form a structural relationship (b).

[0028] like Figure 3As shown, glass fiber aerogel insulation sheets of different thicknesses (i.e., glass fiber aerogel insulation sheet 3 to glass fiber aerogel insulation sheet 8) are used as the insulation layer between the backlight LED and the diffuser plate. The light intensity of the LED as the backlight source is 400W / m 2 The sample was placed above the lamp bead, with the bottom of the diffusion plate close to the thermometer, and after continuous lighting for 1.5 hours, the temperature between the glass fiber aerogel insulation sheet and the diffusion plate was tested to form Examples 1-12.

[0029] In addition, no insulation layer is provided between the diffuser plate and the LED light board, and the above steps are repeated to form control group 1. Glass fiber aerogel insulation sheet 3 is used in combination with diffusers of different thicknesses to form control groups 2-4. Figure 5 Example data sheet shown.

[0030] The surface temperature of the diffuser in control group 1 is 76.3℃, which is higher than the thermal deformation temperature of the diffuser substrate. Long-term use can easily cause the diffuser to deform. Control groups 2-4 show that when the lamp beads come into contact with the glass fiber aerogel insulation sheet, due to heat conduction, although increasing the thickness of the diffuser can also achieve a better light mixing effect, the surface temperature of the diffuser still does not meet the use requirements. In addition, the actual diffuser is compared with the following: Figure 6 As shown, embodiments 1-12 can effectively solve the light homogenization problem of the diffusion plate, and the surface temperature is lower than the thermal deformation temperature. It can be seen that the use of the solution of the present invention can effectively shorten the light mixing distance of the direct-type flat panel display and be used for the direct-type LED backlight display screen.

Claims

1. A backlight module, characterized in that: It includes a diffuser plate with polystyrene material as a substrate; a glass fiber aerogel insulation sheet located on one side of the diffuser plate; and an LED light board located on a side of the glass fiber aerogel insulation sheet facing away from the diffuser plate; the side of the diffuser plate facing the glass fiber aerogel insulation sheet is a light incident surface, and the distance between the LED light board and the light incident surface is 4.065mm-4.637mm; wherein the thickness of the glass fiber aerogel insulation sheet is 1.065mm-3.637mm.

2. The backlight module according to claim 1, characterized in that: The glass fiber aerogel thermal insulation sheet is prepared by taking glass fiber as a base material and compounding silicon dioxide aerogel.

3. The backlight module according to claim 1, characterized in that: The glass fiber aerogel heat insulation sheet is adhered to the light incident surface of the diffusion plate by using UV glue or thermosetting glue, and there is an air layer of 1mm-3mm between the glass fiber aerogel heat insulation sheet and the LED light board.

4. The backlight module according to claim 1, characterized in that: The glass fiber aerogel insulation sheet is placed on the LED lamp board, and the distance between the glass fiber aerogel insulation sheet and the light incident surface is an air layer of 1 mm to 3 mm.

5. A direct-lit LED backlight display screen, characterized in that: Adopt the backlight module of any one of 1-4.

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