CN110824770A

CN110824770A - Backlight module

Info

Publication number: CN110824770A
Application number: CN201911079607.2A
Authority: CN
Inventors: 陆小松
Original assignee: Ningbo Vision Optoelectronics Co Ltd
Current assignee: Ningbo Vision Optoelectronics Co Ltd
Priority date: 2019-11-07
Filing date: 2019-11-07
Publication date: 2020-02-21

Abstract

A backlight module comprises a light source, and is characterized in that: the glass substrate is arranged on the front side of the light source, the optical sheet assembly is arranged above the glass substrate in a clinging mode and comprises a prism sheet and a brightness enhancement sheet which are sequentially arranged, the prism sheet is bonded with the glass substrate through a first adhesive layer, and the prism sheet is bonded with the brightness enhancement sheet through a second adhesive layer. The structure of the backlight module can not only ensure the strength of a plurality of optical sheets, but also avoid the stress or thermal deformation after long-term use, enhance the integral uniformity of a light source and ensure the light-emitting brightness of the light source. Can be widely applied to the field of liquid crystal displays.

Description

Backlight module

Technical Field

The present invention relates to a lighting device, and more particularly, to a backlight module.

Background

In the flat panel display device, the light emission of the liquid crystal display device mainly depends on a backlight module, which generally includes a light source and an optical sheet, which generally includes a light guide plate, a reflective sheet, a light-condensing sheet, and the like, for enhancing and uniformly injecting light emitted from the light source to the liquid crystal display panel, thereby providing a uniform high-brightness light source to the liquid crystal display panel.

The backlight module is generally divided into two types, one type is a side-in type backlight module, a light source is arranged on one side of a light guide plate, linear or point light emitted by the light source is uniformly mixed into a planar light emitting surface through the light guide plate, and then the planar light emitting surface is uniformly mixed or enhanced through other optical sheets and enters a liquid crystal display panel.

The other is a direct type backlight module, such as a direct type LED liquid crystal television backlight structure disclosed in Chinese patent ZL201821271876.X, which comprises a shell, an LCD panel, a brightness enhancement sheet and a prism sheet, wherein a light source is fixedly arranged in the middle of the shell. In the backlight module, in order to reduce the thickness of the whole display, a light guide plate is not usually arranged, so that various optical sheets are directly fixed on the shell in the structure, gaps exist between each layer of optical sheet and between each optical sheet and the light source, and after the backlight module is used for a long time, the stress of the optical sheets is easily uneven and deformed, and further the uniformity and the brightness of the whole light output of the backlight module are influenced.

Disclosure of Invention

The invention aims to solve the technical problem of the backlight module which can ensure the strength of the optical sheet, prevent the optical sheet from being deformed by stress and ensure the integral emergent brightness.

The technical scheme adopted by the invention for solving the technical problems is as follows: a backlight module comprises a light source, and is characterized in that: the glass substrate is arranged on the front side of the light source, the optical sheet assembly is arranged on the front side of the glass substrate in a clinging mode and comprises a prism sheet and a brightness enhancement sheet which are sequentially arranged, the prism sheet is bonded with the glass substrate through a first adhesive layer, and the prism sheet is bonded with the brightness enhancement sheet through a second adhesive layer.

As a preferred embodiment of the present invention, the prism sheet is divided into three layers, which are a base layer, a protrusion layer and a filling layer, wherein the base layer is planar, the protrusion layer is a prism structure, the filling layer fills the positions between the prism structures, and the upper surface of the filling layer is planar and is bonded to the second adhesive layer.

Preferably, the prism structure of the bump layer is left-right symmetrical in shape, the refractive index of the bump layer is n1, the refractive index of the filling layer is n2, and n2-n1> 0.1.

More preferably, n2-n1> 0.2.

Preferably, the cross section of the prism structure of the convex layer is an isosceles triangle, and the vertex angle of the isosceles triangle is less than 90 degrees.

Preferably, the prismatic structures of the raised layer are of the same size and in a continuous pattern.

Preferably, the first adhesive layer and the second adhesive layer are optical adhesives.

Preferably, the positions of the corners of the prismatic structures of the raised layer are chamfered.

Preferably, two side surfaces of the prism structure of the convex layer are concave surfaces or convex surfaces, and meanwhile, in the cross section of the prism structure, two sides of the prism structure are respectively a concave arc line and a convex arc line, the concave arc line and the convex arc line are connected at a vertex, and an angle formed by the vertex and a connecting line between two ends of the bottom edge of the cross section of the prism structure is smaller than 90 degrees.

Preferably, the base angle of the isosceles triangle ranges from 45 degrees to 80 degrees.

Compared with the prior art, the backlight module has the advantages that the structure of the backlight module can ensure the strength of a plurality of optical sheets, can not be stressed or heated to deform after being used for a long time, can enhance the integral uniformity of a light source, and ensures the emergent brightness of the light source.

Drawings

Fig. 1 is a schematic view of a backlight module according to an embodiment of the invention.

Fig. 2 is a schematic light path diagram of a backlight module according to an embodiment of the invention.

Fig. 3 is a schematic view of an optical path of the prism sheet according to the embodiment of the present invention.

FIG. 4a is a schematic cross-sectional view of one embodiment of a prism sheet according to an embodiment of the present invention; fig. 4b is a schematic cross-sectional view of another embodiment of the prism sheet according to an embodiment of the present invention.

Detailed Description

The invention is described in further detail below with reference to the embodiments of the drawing, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

As shown in fig. 1, the backlight module of the embodiment of the invention includes a light source 1, a glass substrate 2 disposed in front of the light source 1, and an optical sheet assembly disposed in close contact with the front of the glass substrate 2, wherein the optical sheet assembly includes a plurality of optical sheets bonded to each other. Specifically, the plurality of optical sheets include a prism sheet 3 disposed on the glass substrate 2 and a brightness enhancement sheet 4 disposed on the prism sheet 3. The first adhesive layer 81 is disposed between the glass substrate 2 and the prism sheet 3, and the second adhesive layer 82 is disposed between the prism sheet 3 and the brightness enhancement sheet 4. The first glue layer 81 and the second glue layer 82 are both glue layers having a bonding effect, so that the glass substrate 2 and the optical sheet assembly can be bonded through the glue layers or not, and the optical sheets are bonded through the glue layers to form the optical sheet assembly integrally.

The glue layers, such as the first glue layer 81 and the second glue layer 82, are used to bond the glass substrate 2, the prism sheet 3 and the brightness enhancement sheet 4 into a whole, and since the glass substrate 2 is disposed, the hardness of the whole optical sheet assembly is high, and the optical sheet assembly is not deformed by force or by heat after being used for a long time, so that the uniformity and brightness of the light source are affected. Therefore, the glass substrate, the prism sheet 3 and the brightness enhancement sheet 4 are bonded together through the adhesive layer without any air layer therebetween, so that the overall light loss is smaller, the brightness of the overall backlight module can be increased, and the brightness enhancement sheet 4 can be a reflection-type polarization brightness enhancement sheet. Moreover, as will be understood by those skilled in the art, the glass substrate and the optical sheet assembly may be disposed closely to each other without a glue layer, i.e., the first glue layer is omitted. However, after the glass substrate and the optical sheet assembly are bonded with each other, the optical sheets of the whole backlight module are integrated, so that the installation is more convenient and the integral strength is improved.

The glass substrate 2 may be made of glass material without any other optical structure, or may be a glass plate with other optical structures, such as a prism sheet, a light-gathering sheet, etc., which may also be made of glass material, as long as the glass material has a certain hardness and can bear load.

Preferably, the material of the first adhesive layer and the second adhesive layer may be optical adhesive, such as UV adhesive, thermal curing liquid adhesive, dry film adhesive, and the like, and the material of the first adhesive layer and the second adhesive layer may be the same or different.

As shown in fig. 1 and 2, the prism sheet 3 is divided into three layers, namely, a base layer 31, a bump layer 32 disposed on the base layer 31, and a filling layer 33 disposed on the bump layer 32. The base layer 31 is a flat sheet, the bump layer 32 is a prism structure, the filling layer 33 completely fills the positions between the prism structures of the bump layer 32, the upper surface of the whole filling layer 33 is a flat surface, and the flat upper surface of the filling layer 33 is bonded with the brightness enhancement sheet 4 through the second adhesive layer 82.

The material of the base layer 31 is PET, the material of the bump layer 32 may be polyacrylate containing an auxiliary agent for UV-induced crosslinking, the refractive index of the bump layer 32 is n1, the filling layer 33 is a low-refractive-index light-transmitting material, and may be a fluorine-containing monomer such as hexafluorobutyl acrylate, hexafluoroisopropyl methacrylate, etc., and the refractive index of the filling layer 33 is n 2.

As shown in fig. 1-3,4a and 4b, the prism structure of the convex layer on the prism sheet can be a continuous prism structure, as shown in fig. 3, i.e. there is no space between the prisms, and the cross section of the prisms is isosceles triangle, or at least a pattern of left-right symmetrical structure, and the prism structure is an equal periodic pattern, i.e. the size of each prism pattern is the same.

However, it will be understood by those skilled in the art that the prism structure of the embossed layer on the prism sheet may be a pattern having irregular and unequal intervals. For example, the prism patterns may have different sizes, and the prism patterns may have no space therebetween, but the prism patterns may be arranged at different sizes, or may be arranged from small to large or from large to small according to the size of the patterns; in addition, the patterns of the prisms can be arranged at intervals, and the intervals can be equal, can be gradually increased or gradually decreased, or can be provided with a plurality of different interval distances, and the interval distances can appear in sequence. The size, the arrangement period, the arrangement interval and the like of the patterns of the prisms can be matched with the grating film in front of the display screen, and therefore the effect of reducing the moire patterns in the three-dimensional display mode is achieved.

As shown in fig. 2, the schematic diagram of the light path of the light incident on the optical sheet assembly is that, since there is no air layer between the sheets of the optical sheet assembly, the overall strength is higher, the optical sheet assembly is not easy to be stressed and deformed by heating, and is convenient to install, and the structure of the prism sheet is adopted, so that the emergent light brightness is higher and more converged, and further the backlight brightness of the whole liquid crystal display is also improved.

As shown in fig. 3, which is a schematic view of light incident to the prism sheet. As shown in table 1 below, is the difference between the on-axis gain and the half-intensity angle a of the light for the various embodiments.

TABLE 1

Where θ is the base angle in the prism cross section, the prism sheet used in comparative example 4 has no filler layer, i.e., the prism sheet is a general prism sheet, and thus n2 is 1. It can be seen from the table that the base angle of the prism cross section and the refractive index of the prism material are not simply linear relationships with the axial gain and half-intensity angle of the light beam, and the relationship among several parameters needs to be considered in order to achieve better uniformity and increase the brightness of the light source.

The prism cross-section of the bump layer 32 is an isosceles triangle, and the angle of the apex angle in the prism cross-section of the bump layer is less than 90 degrees, preferably, the base angle thereof is in the range of 45 ° to 80 °, and more preferably, the base angle is 70 °. And, in order to secure light diffusion and uniformity effects of the prism sheet without lowering overall brightness, n2-n1>0.1, preferably n2-n1> 0.2.

Preferably, the positions of the corners of the prisms of the relief layer may form chamfers. The upper surface of the filling layer 43 is higher than or equal to the height of the apex angle of the prism of the bump layer, and preferably, the apex angle of the prism of the bump layer is also provided with a chamfer. And preferably, the prism side surface can also be a convex arc surface, as shown in fig. 4a, and the vertex angle position is also provided with a chamfer; or may be a concave arcuate surface. Meanwhile, in the two embodiments, two sides of the cross section of the prism are respectively convex or concave arc lines, and the concave arc line and the convex arc line intersect at a fixed point, and an angle formed between the top point and a connecting line at two ends of the bottom surface of the prism is the same as the top angle and is also smaller than 90 degrees. As shown in fig. 4 b.

Moreover, it can be understood by those skilled in the art that the backlight module may further include other optical sheets, as long as the optical sheet assembly of the backlight module includes a plurality of optical sheet assemblies integrally bonded to each other, for example, another optical sheet may be further disposed below the glass substrate, and another optical sheet, such as a second brightness enhancement sheet, may be further disposed above the brightness enhancement sheet. Or a second prism sheet, diffusion sheet, etc. may be added between the prism sheet and the brightness enhancement sheet.

Since the glass substrate is added, light incident from the light source to the prism sheet is reduced, and the prism sheet is configured such that light incident from the light source to the glass substrate and the prism sheet is uniformly and brightly enhanced. Therefore, the brightness and the uniformity of emergent light of the whole backlight module are improved, and the optical sheet of the whole backlight module can not be deformed due to heating or stress. And the whole optical sheet assembly is integrally bonded through the glue layer, so that the optical sheet assembly is convenient to mount and not easy to damage.

Although preferred embodiments of the present invention have been described in detail hereinabove, it should be clearly understood that modifications and variations of the present invention are possible to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A backlight module comprising a light source (1), characterized in that: the glass substrate (2) is arranged on the front side of the light source, the optical sheet assembly is arranged on the front side of the glass substrate (2) in a clinging mode and comprises a prism sheet (3) and a brightness enhancement sheet (4) which are sequentially arranged, the prism sheet is bonded with the glass substrate (2) through a first glue layer (81), and the prism sheet (3) is bonded with the brightness enhancement sheet (4) through a second glue layer (82).

2. The backlight module of claim 1, wherein: the prism sheet (3) is divided into three layers, namely a base layer (31), a convex layer (32) and a filling layer (33), the base layer (31) is planar, the convex layer (32) is of a prism structure, the filling layer (33) fills positions between the prism structures, the upper surface of the filling layer (33) is a plane, and the upper surface of the filling layer (33) is bonded with the second glue layer (82).

3. The backlight module of claim 2, wherein: the prism structure of the bump layer (32) is left-right symmetrical in shape, the refractive index of the bump layer (32) is n1, the refractive index of the filler layer (33) is n2, and n2-n1> 0.1.

4. The backlight module of claim 3, wherein: n2-n1> 0.2.

5. The backlight module of claim 3, wherein: the cross section of the prism structure of the convex layer (32) is an isosceles triangle, and the vertex angle of the isosceles triangle is smaller than 90 degrees.

6. The backlight module of claim 3, wherein: the prismatic structures of the raised layer (32) are in a pattern of equal size and continuity.

7. The backlight module of claim 2, wherein: the first adhesive layer (81) and the second adhesive layer (82) are optical adhesives.

8. The backlight module of claim 5, wherein: and the corners of the prism structures of the convex layers are provided with chamfers.

9. The backlight module of claim 3, wherein: the two side surfaces of the prism structure of the convex layer (32) are concave surfaces or convex surfaces, meanwhile, in the cross section of the prism structure, the two sides of the prism structure are respectively a concave arc line and a convex arc line, the concave arc line and the convex arc line are connected at the top point, and the angle formed by the top point and a connecting line between the two ends of the bottom edge of the cross section of the prism structure is smaller than 90 degrees.

10. The backlight module of claim 5, wherein: the base angle range of the isosceles triangle is 45-80 degrees.