CSP backlight source and display device

Abstract

The utility model relates to the technical field of backlight of display equipment, and provides a CSP backlight source and a display device. The CSP backlight comprises: a substrate comprising a light emitting circuit; the light-emitting packaging part is arranged on the substrate, electrically connected with the light-emitting circuit and comprises a blue light chip and a red-green fluorescence conversion layer which are sequentially stacked from bottom to top, and the red-green fluorescence conversion layer at least covers the blue light chip and is used for converting and mixing light emitted by the blue light chip so as to emit white light; the light-emitting packaging piece is manufactured through a chip scale package (CSP) technology; the diffusion reflection layer covers the light-emitting packaging piece in a gapless mode, the diffusion reflection layer comprises a cup-shaped diffusion part and a reflection part arranged on the periphery of the diffusion part, and the diffusion powder concentration of the central area of the diffusion part is larger than that of the edge area of the diffusion part; and the lens covers the diffusion reflection layer in a gapless manner.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of display device backlight, in particular to a CSP backlight source and a display device. BACKGROUND

[0002] At present, the white backlight is usually realized by using a blue light emitting chip to excite quantum dots or fluorescent powder in the LED display scheme.

[0003] In the prior art, a blue light chip can be used to excite red and green light in cooperation with a red and green fluorescent layer, and white light is obtained by mixing, and then a diffusion layer and a reflection layer are sequentially used to improve the diffusion angle. Due to the high blocking efficiency of the reflection layer to light, color difference may occur in the central region of the backlight source. CONTENT OF THE UTILITY MODEL

[0004] Therefore, the present disclosure provides a CSP backlight source and a display device to solve the technical problem of color difference in the central region of the backlight source in the prior art.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present disclosure is as follows:

[0006] In a first aspect, the present disclosure provides a CSP backlight source, which comprises: a substrate comprising a light emitting circuit; a light emitting package arranged on the substrate and electrically connected with the light emitting circuit, comprising a blue light chip and a red and green fluorescent conversion layer stacked in turn from bottom to top, the red and green fluorescent conversion layer covering at least the top of the blue light chip, used for converting and mixing the light emitted by the blue light chip to emit white light, the light emitting package being made by chip scale package (CSP) technology; a diffusion reflection layer covering the light emitting package without gaps, the diffusion reflection layer comprising a cup-shaped diffusion part and a reflection part arranged around the diffusion part, the diffusion powder concentration of the central region of the diffusion part being greater than that of the edge region of the diffusion part; and a lens covering the diffusion reflection layer without gaps.

[0007] In one embodiment, the blue light chip is a MiniLED blue light chip.

[0008] In one embodiment, the diffusion powder concentration of the diffusion part gradually decreases from the central region to the edge region.

[0009] In one embodiment, the diffusion powder concentration of the central region is a fixed first value, and the diffusion powder concentration of the edge region is a fixed second value, the first value being greater than the second value.

[0010] In one embodiment, the red and green fluorescent conversion layer comprises a red fluorescent conversion layer and a green fluorescent conversion layer arranged in layers, or the red and green fluorescent conversion layer comprises a mixed fluorescent conversion layer mixed with red fluorescent powder and green fluorescent powder.

[0011] In one embodiment, the diffusion part is a white glue layer or a silica gel layer containing diffusion powder; and / or, the reflection part is a white glue layer or a silica gel layer containing diffusion powder.

[0012] In one embodiment, the diffusion powder includes solid particles of silica, titanium dioxide or a mixture of silica and titanium dioxide.

[0013] In one embodiment, the CSP backlight source further includes an optical film assembly arranged in the light emitting direction of the light emitting package.

[0014] In one embodiment, the interface between the light emitting package and the diffusion reflection layer is a plane, the interface between the diffusion reflection layer and the lens is a curved surface, and the curved surface is convex in the direction away from the blue light chip.

[0015] In a second aspect, the present disclosure provides a display device, comprising a display panel and the CSP backlight source in the above technical solution.

[0016] Compared with the prior art, the present disclosure has the following beneficial effects: by using the diffusion reflection layer including the diffusion part and the reflection part, and setting the diffusion powder concentration of the central region of the diffusion part to be greater than the diffusion powder concentration of the edge region of the diffusion part, more light in the central region can be diffused to the surrounding, thereby reducing the color difference in the central region of the backlight source. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present disclosure, and other drawings can be obtained by those skilled in the art without creative effort based on these drawings.

[0018] Figure 1 is a schematic diagram of a CSP backlight source provided by an embodiment of the present disclosure;

[0019] Figure 2 is a schematic diagram of another CSP backlight source provided by an embodiment of the present disclosure;

[0020] Figure 3 is a schematic diagram of still another CSP backlight source provided by an embodiment of the present disclosure;

[0021] Figure 4 is a schematic diagram of still another CSP backlight source provided by an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present disclosure clearer, the present disclosure will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and not intended to limit the present disclosure.

[0023] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly or indirectly on the other component. When a component is referred to as being "connected to" another component, it can be directly or indirectly connected to the other component. The terms "upper", "lower", "left", "right", "front", "back", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate the orientation or position shown in the drawings and are used only for convenience of description, and should not be construed as limiting the technical solutions. The terms "first", "second" are only used for convenience of description, and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0024] The CSP backlight and display device according to the embodiments of the present disclosure will be described in detail below in combination with the drawings. For the convenience of structure description, the front light-emitting direction of the backlight is taken as an example in the following description, and the front side is the light-emitting direction.

[0025] Figure 1 is a schematic diagram of a CSP backlight provided by an embodiment of the present disclosure; Figure 2 is a schematic diagram of another CSP backlight provided by an embodiment of the present disclosure; Figure 3 is a schematic diagram of still another CSP backlight provided by an embodiment of the present disclosure, Figure 4 is a schematic diagram of still another CSP backlight provided by an embodiment of the present disclosure. The CSP backlight and display device provided by the embodiments of the present disclosure will be described below in combination with Figures 1 to 4

[0026] As shown in Figures 1 to 3 , the CSP (Chip Scale Package) backlight provided by the embodiments of the present disclosure includes a substrate, a light-emitting package, a diffusion reflection layer, and a lens. The light-emitting package is electrically connected to the circuit layer of the substrate and includes a blue light chip and a red-green fluorescent conversion layer stacked in order from bottom to top, and the red-green fluorescent conversion layer covers at least the top of the blue light chip. The stacking from bottom to top means that the red-green fluorescent conversion layer is stacked on the front side of the blue light chip.

[0027] ​Specifically, the substrate includes a circuit layer, the circuit layer includes a light-emitting circuit, and the light-emitting package is electrically connected with the light-emitting circuit. Electrodes of the blue light chip are welded on the light-emitting circuit of the substrate, so that the blue light chip is located on the front side surface of the substrate. The front side surface of the blue light chip is the main light-emitting surface, and thus the front side surface of the blue light chip is defined as the light-emitting front surface, and the side surface around the blue light chip is the light-emitting side surface. The light-emitting package is arranged on the front side surface of the substrate and is electrically connected with the circuit layer. The light-emitting package can be welded on the substrate by using a COB (Chip-On-Board, chip-on-board packaging) flip process. The light-emitting package emits white light towards the light-emitting direction. The diffusion reflection layer and the lens cover the light-emitting package without gaps, and the diffusion reflection layer, the lens and the light-emitting package are combined without gaps, so that each light-emitting package has sufficient light-emitting angle.

[0028] As shown in Figure 1 The CSP backlight source provided by the embodiment of the present disclosure includes: a substrate 110 including a light-emitting circuit; a light-emitting package arranged on the substrate and electrically connected with the light-emitting circuit, including a blue light chip 121 and a red-green fluorescent conversion layer 122 stacked in turn from bottom to top, the red-green fluorescent conversion layer covers the top and side of the blue light chip, and is used for converting and mixing the light emitted by the blue light chip to emit white light, the light-emitting package is made by CSP technology; a diffusion reflection layer, the diffusion reflection layer covers the light-emitting package without gaps, the diffusion reflection layer includes a cup-shaped diffusion part 131 and a reflection part 132 arranged around the diffusion part, the diffusion powder concentration of the central region of the diffusion part is greater than the diffusion powder concentration of the edge region of the diffusion part; a lens 140, the lens covers the diffusion reflection layer without gaps. In the embodiment of the present disclosure, the diffusion powder concentration of the diffusion part can gradually decrease from the central region to the edge region. For example, the diffusion powder concentration can linearly decrease.

[0029] In the embodiment of the present disclosure, the cup opening of the cup-shaped diffusion part faces the blue light chip.

[0030] In one embodiment, the red-green fluorescent conversion layer 122 can be a red-green mixed fluorescent conversion layer mixed with red fluorescent powder and green fluorescent powder in the packaging glue, or can be composed of a red fluorescent conversion layer and a green fluorescent conversion layer arranged in turn from bottom to top. The red fluorescent conversion layer can be formed by mixing red fluorescent powder in the packaging glue, and the green fluorescent conversion layer can be formed by mixing green fluorescent powder in the packaging glue. In addition, the positions of the red fluorescent conversion layer and the green fluorescent conversion layer can be transposed, that is, the red-green fluorescent conversion layer 122 is composed of a green fluorescent conversion layer and a red fluorescent conversion layer arranged in turn from bottom to top.

[0031] The red-green fluorescent conversion layer 122 is a red-green mixed fluorescent conversion layer in which red fluorescent powder and green fluorescent powder are mixed in the encapsulation glue. When the blue light emitted by the blue light chip is irradiated onto the red-green fluorescent conversion layer 122, mixed light of red light and green light can be converted, and the mixed light and the blue light form white light together, so that the light emitting package emits white light.

[0032] When the red-green fluorescent conversion layer 122 is composed of a red fluorescent conversion layer and a green fluorescent conversion layer stacked together, the blue light emitted by the blue light chip is irradiated onto the red fluorescent conversion layer and the green fluorescent conversion layer, and red light and green light can be converted respectively. The red light, the green light and the blue light form white light together, so that the light emitting package emits white light.

[0033] In the embodiment, the blue light chip can emit light from five sides, that is, the four light-emitting side surfaces and the one light-emitting front surface of the blue light chip can all emit light. In the embodiment, the blue light chip 121 and the red-green fluorescent conversion layer 122 can be made into a high color gamut white light emitting package by the CSP technology. In the light emitting package, the light emitted by the blue light chip 121 is irradiated onto the red-green fluorescent conversion layer, and the light is converted by the red-green fluorescent conversion layer and mixed with the blue light to form white light and emit white light. The light emitting package with direct packaging has high cost performance.

[0034] In the technical solution of the embodiment of the present disclosure, different concentrations of diffusion powder are arranged in different regions of the diffusion part. High-concentration diffusion powder is arranged in the central region of the diffusion part, and the concentration of the diffusion powder gradually decreases from the central region to the edge region. Since the greater the concentration of the diffusion powder, the better the diffusion effect, the light in the central region can be diffused more to the surrounding. The region where the diffusion powder of the diffusion part in the diffusion reflection layer is cup-shaped, and the reflection part of the diffusion reflection layer is arranged around the diffusion part, which can reduce the risk of color difference in the central region of the diffusion part which is also the central region of the diffusion reflection layer.

[0035] As Figure 2As shown, another CSP backlight source provided by the embodiment of the present disclosure includes: a substrate 210 including a light emitting circuit; a light emitting package disposed on the substrate and electrically connected with the light emitting circuit, including a blue light chip 221 and a red-green fluorescent conversion layer 222 stacked in turn from bottom to top, the red-green fluorescent conversion layer covers the top and side of the blue light chip, for converting and mixing the light emitted by the blue light chip to emit white light, the light emitting package is made by CSP technology; a diffusion reflection layer, the diffusion reflection layer covers the light emitting package without gap, the diffusion reflection layer includes a cup-shaped diffusion part and a reflection part 232 disposed around the diffusion part, the diffusion powder concentration of the central region of the diffusion part is greater than the diffusion powder concentration of the edge region of the diffusion part; a lens 240, the lens covers the diffusion reflection layer without gap. In this embodiment, the diffusion powder concentration of the central region 2311 of the diffusion part is a fixed first value, the diffusion powder concentration of the edge region 2312 of the diffusion part is a fixed second value, and the first value is greater than the second value.

[0036] In this embodiment, the blue light chip can be five-sided light emitting, that is, the four light emitting sides and one light emitting front of the blue light chip can emit light. In this embodiment, the blue light chip 221 and the red-green fluorescent conversion layer 222 can be made into a high color gamut white light emitting package by CSP technology. In the light emitting package, the light emitted by the blue light chip 221 is irradiated onto the red-green fluorescent conversion layer, and after being converted by the red-green fluorescent conversion layer, the light is mixed with the blue light to form white light and emit.

[0037] The technical solution in the embodiment of the present disclosure sets different concentrations of diffusion powder in different regions of the diffusion part, wherein high-concentration diffusion powder of a first value is set in the central region of the diffusion part, and low-concentration diffusion powder of a second value is set in the edge region of the diffusion part. Since the greater the diffusion powder concentration, the better the diffusion effect, the light in the central region can be diffused more to the periphery, the region where the diffusion powder of the diffusion part in the diffusion reflection layer is cup-shaped, and the reflection part of the diffusion reflection layer is disposed around the diffusion part, which can reduce the risk of color difference in the central region of the diffusion part which is also the central region of the diffusion reflection layer.

[0038] As Figure 3As shown, the CSP backlight provided by the embodiment of the present disclosure includes: a substrate 310 including a light emitting circuit; a light emitting package arranged on the substrate and electrically connected with the light emitting circuit, including a blue light chip 321 and a red-green fluorescent conversion layer 322 stacked in turn from bottom to top, the red-green fluorescent conversion layer covers the top of the blue light chip and does not cover the side of the blue light chip, for converting and mixing the light emitted by the blue light chip to emit white light, the light emitting package is made by CSP technology; a diffusion reflection layer, the diffusion reflection layer covers the light emitting package without gap, the diffusion reflection layer includes a cup-shaped diffusion part 331 and a reflection part 332 arranged around the diffusion part, the diffusion powder concentration of the central region of the diffusion part is greater than the diffusion powder concentration of the edge region of the diffusion part; a lens 340, the lens covers the diffusion reflection layer without gap. In the embodiment of the present disclosure, the diffusion powder concentration of the diffusion part can gradually decrease from the central region to the edge region.

[0039] In the embodiment, the blue light chip can be single-sided light emitting, that is, the blue light chip only has one light emitting front surface for light emitting. In this embodiment, the blue light chip 321 and the red-green fluorescent conversion layer 322 can be made into a high color gamut white light emitting package by CSP technology. In the light emitting package, the light emitted by the blue light chip 321 is irradiated onto the red-green fluorescent conversion layer, and after being converted by the red-green fluorescent conversion layer, the light is mixed with the blue light to form white light.

[0040] The technical solution in the embodiment of the present disclosure sets different concentrations of diffusion powder in different regions of the diffusion part, wherein high-concentration diffusion powder is arranged in the central region of the diffusion part, and the diffusion powder concentration gradually decreases from the central region to the edge region. Since the greater the diffusion powder concentration, the better the diffusion effect, the light in the central region can be diffused more to the surrounding. The region where the diffusion powder of the diffusion part in the diffusion reflection layer is cup-shaped, and the reflection part of the diffusion reflection layer is arranged around the diffusion part, which can reduce the risk of color difference in the central region of the diffusion part which is also the central region of the diffusion reflection layer.

[0041] In the embodiment of the present disclosure, the blue light chip can be a MiniLED blue light chip. The MiniLED refers to an LED chip with a size of 100 μm, and the light emitting package emits white light. Since the light emitting chip is a MiniLED, a high color gamut white light MiniCOB package is formed. Preferably, the blue light chip is generally circular or square, and the excitation wavelength is 440 nm to 470 nm.

[0042] In the embodiments of the present disclosure, the red-green fluorescent conversion layer can be a nitride fluorescent powder layer, a fluoride fluorescent powder layer and a silicate fluorescent powder layer composed of nitride fluorescent powder, fluoride fluorescent powder and silicate fluorescent powder. When the red-green fluorescent conversion layer is a red fluorescent conversion layer and a green fluorescent conversion layer arranged in layers, red fluorescent powder can be mixed in the packaging glue to form the red fluorescent conversion layer, and green fluorescent powder can be mixed in the packaging glue to form the green fluorescent conversion layer.

[0043] In the embodiments of the present disclosure, the red-green fluorescent powder can be a narrow peak width fluorescent powder such as green β-sialon, and the red fluorescent powder can be a narrow peak width red fluorescent powder such as KSF or QD, and the like, but is not limited thereto. When the red-green fluorescent conversion layer is a red fluorescent conversion layer and a green fluorescent conversion layer arranged in layers, the blue light emitted by the blue light chip can be converted into red light and green light when the blue light is irradiated onto the red-green fluorescent conversion layer, and the red light and green light can be mixed with the blue light to form white light, so that the light emitting package emits white light.

[0044] In the embodiments of the present disclosure, the front surface of the lens is in the shape of a circular arc, and the light emitting package is located at an intermediate position inside the lens in the shape of a circular arc. With the center of the light emitting package as an optical center, the entire light emitting package is covered by the diffusing reflective layer and the lens, so that the beam angle of the light emitting package can be opened. The diffusing reflective layer, the lens and the light emitting package are combined to form an integrated body without gaps or cavities in the middle, so that the diffusing reflective layer, the lens and the light emitting package form an optical lens structure with a large light emitting angle. Opening the light emitting angle of the light emitting package can obtain a larger coverage area, so that the number of Mini LEDs used can be reduced under the same specifications.

[0045] Specifically, in the embodiments of the present disclosure, the diffusing reflective layer and the lens can be arranged in sequence from bottom to top, i.e., the diffusing reflective layer is arranged on the front side of the light emitting package, and the lens is arranged on the front side of the diffusing reflective layer.

[0046] In the embodiments of the present disclosure, the diffusing part can be a white glue layer or a silicone glue layer containing diffusing powder, and the reflective part can be a white glue layer or a silicone glue layer containing diffusing powder. The diffusing powder can be solid particles of silicon dioxide, titanium dioxide or a mixture of silicon dioxide and titanium dioxide. The diffusing powder in the embodiments of the present disclosure can enhance the light diffusivity of the lens, so that the light emitted by the light source can be more uniformly distributed, reducing glare and shadows. In addition, the diffusing powder can maintain a high light transmittance while ensuring the light diffusing effect, reducing the loss of light energy.

[0047] In the embodiments of the present disclosure, the interface between the light emitting package and the diffusing reflective layer is a plane, the interface between the diffusing reflective layer and the lens is a curved surface, and the curved surface is convex in a direction away from the blue light chip.

[0048] Specifically, when the front side surface of the light emitting package is a plane, the interface between the light emitting package and the diffusion reflection layer is a plane, and the back side surface of the diffusion reflection layer is a plane, the diffusion reflection layer can cover the light emitting package without gaps, and each light emitting package has a sufficient light emitting angle. When the front side surface and the back side surface of the lens are both curved surfaces, and the interface between the diffusion reflection layer and the lens is a curved surface, the diffusion reflection layer and the lens can cover the light emitting package without gaps in sequence, and each light emitting package has a sufficient light emitting angle.

[0049] As shown in Figure 4 The CSP backlight source in the embodiment of the present disclosure further includes an optical film assembly, which is arranged in the light emitting direction of the light emitting package. The optical film assembly includes a composite optical film material 410 and a diffusion plate 420, the diffusion plate 420 is arranged in the light emitting direction of the lens, and the composite optical film material 410 is located in front of the diffusion plate 420. The optical film assembly can change the propagation and reflection direction of light, and can be single-layer or multi-layer, composed of different kinds of materials. The optical film assembly can achieve different effects by changing different parameters such as materials, thickness, reflectivity, and transmittance.

[0050] The composite optical film material is a multifunctional optical film material that assembles multiple different optical films into a single film through a composite process. The composite optical film material can achieve overall thinness and cost reduction of the display device while maintaining its optical performance, and improve the yield and efficiency of backlight module assembly. The diffusion plate is a component used in optical systems, and its main function is to diffuse or uniformly distribute light. Through surface frosting, dotting, prism, and other processing techniques, the diffusion plate can uniformly diffuse light, reduce glare and bright spots, and improve the uniformity and softness of light. In the field of backlight modules and other fields, the diffusion plate is used to uniformly diffuse the light emitted by the backlight lamp to the entire screen to improve the uniformity and softness of the light. The diffusion plate is usually made of materials with high light transmittance and good diffusion performance, such as PS (polystyrene), PC (polycarbonate), and acrylic.

[0051] Based on the above CSP backlight source, the embodiment of the present disclosure can also provide a display device, which includes a display panel and the CSP backlight source in the above technical solution.

[0052] According to the CSP backlight source provided by the embodiment of the present disclosure, by using the diffusion reflection layer including the diffusion part and the reflection part, and setting the diffusion powder concentration of the central region of the diffusion part to be greater than the diffusion powder concentration of the edge region of the diffusion part, the light of the central region can be more diffused to the surrounding, thereby reducing the color difference of the central region of the backlight source.

[0053] The above merely provides preferred embodiments of the present disclosure, and is not used to limit the present disclosure. Any modification, equivalent replacement, and improvement made in the spirit and principle of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A CSP backlight, characterized by, The CSP backlight source comprises: a substrate comprising a light emitting circuit; a light emitting package arranged on the substrate and electrically connected with the light emitting circuit, comprising a blue light chip and a red-green fluorescent conversion layer stacked in turn from bottom to top, the red-green fluorescent conversion layer covering at least above the blue light chip, for converting and mixing light emitted by the blue light chip to emit white light, the light emitting package being made by a chip scale package (CSP) technology; a diffusion reflection layer covering the light emitting package without gap, the diffusion reflection layer comprising a cup-shaped diffusion part and a reflection part arranged around the diffusion part, the diffusion powder concentration of a central region of the diffusion part being greater than that of an edge region of the diffusion part; a lens covering the diffusion reflection layer without gap.

2. The CSP backlight of claim 1, wherein, The blue light chip is a MiniLED blue light chip.

3. The CSP backlight of claim 1, wherein, The diffusion powder concentration of the diffusion part gradually decreases from the central region to the edge region.

4. The CSP backlight of claim 1, wherein, The diffusion powder concentration of the central region is a fixed first value, and the diffusion powder concentration of the edge region is a fixed second value, the first value being greater than the second value.

5. The CSP backlight of claim 1, wherein, The red-green fluorescent conversion layer comprises a red fluorescent conversion layer and a green fluorescent conversion layer arranged in layers, or the red-green fluorescent conversion layer comprises a mixed fluorescent conversion layer mixed with red fluorescent powder and green fluorescent powder.

6. The CSP backlight of claim 1, wherein, The diffusion part is a white glue layer or a silica gel layer containing diffusion powder; and / or the reflection part is a white glue layer or a silica gel layer containing diffusion powder.

7. The CSP backlight of claim 6, wherein, The diffusion powder comprises solid particles of silica, titanium dioxide or a mixture of silica and titanium dioxide.

8. The CSP backlight of claim 1, wherein, The CSP backlight source further comprises an optical film assembly arranged in a light emitting direction of the light emitting package.

9. The CSP backlight of claim 1, wherein, An interface between the light emitting package and the diffusion reflection layer is a plane, an interface between the diffusion reflection layer and the lens is a curved surface, and the curved surface is convex in a direction away from the blue light chip.

10. A display device, characterized by comprising: The CSP backlight source comprises a display panel and any one of claims 1-9.

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