TWI504940B - Diffusion plate and direct-type backlight module - Google Patents

Description

Diffuser and direct backlight module

The present invention relates to a diffuser panel, and more particularly to a diffuser panel having an oblique support sheet and a direct type backlight module using the same.

With the advancement of modern video technology, liquid crystal displays have been widely used as display screens in consumer electronic products such as mobile phones, notebook computers and desktop computers. However, since the liquid crystal display panel of the liquid crystal display itself does not have the function of emitting light, it is necessary to configure a backlight module under the liquid crystal display panel to provide a light source required for the liquid crystal display panel, thereby enabling the liquid crystal display panel to achieve the display effect.

In general, the backlight module can be divided into a direct-lit backlight module and a side-lit backlight module. At present, the direct-lit backlight module or the side-lit backlight module generally uses a light-emitting diode (LED) with a relatively good luminous efficiency as a light source, thereby reducing the amount of light source used. Reduce production costs. For the direct type backlight module, when the usage of the light source is decreased, the distance between the light sources is necessarily increased. In the above case, in order to avoid the mura phenomenon of the surface light source provided by the direct type backlight module, it is usually necessary to increase The distance between the light source and the diffuser. However, if the distance between the light source and the diffusion plate is increased, the overall thickness of the direct type backlight module is increased, so that the thinning requirement cannot be satisfied. Therefore, how to develop a direct-type backlight module that can provide a uniform surface light source is one of the problems to be solved at present.

The present invention provides a diffuser panel having a longer light exit path.

The invention provides a direct type backlight module, which can provide a uniform surface light source.

The diffusion plate of the present invention includes a first diffusion sheet, a second diffusion sheet, and a plurality of oblique support sheets. Each of the diagonal support sheets has opposing first and second sides. The first side is connected to the first diffusion sheet, and the second side is connected to the second diffusion sheet. The orthographic projections of any two adjacent diagonal support sheets on the first diffusion sheet overlap each other. The reflectance of the diagonal support piece is higher than the reflectance of the first diffusion piece and the second diffusion piece.

In an embodiment of the invention, the area of the overlapping portion of the orthographic projection of any two adjacent oblique supporting sheets on the first diffusion sheet is in the first diffusion with respect to one of the two adjacent oblique supporting sheets. The ratio of the area of the orthographic projection on the sheet is 5% to 90%.

In an embodiment of the present invention, in a cross section perpendicular to the first diffusion sheet and the oblique support sheet, a connection point and a second side of the first side of the oblique support sheet and the first diffusion sheet The connection point with the second diffusion sheet constitutes a connection line, and the angle between the connection line and the first diffusion sheet is 10 to 40 degrees.

In an embodiment of the invention, the first diffusion sheet and the second diffusion sheet have a transmittance of 75% to 90%.

In an embodiment of the invention, the oblique support sheet has a reflectance of 80% to 100%.

In an embodiment of the invention, the weight percentage of the light diffusing agent in the components of the first diffusion sheet and the second diffusion sheet is lower than the weight percentage of the light diffusing agent in the composition of the oblique supporting sheet.

In an embodiment of the invention, the ratio of the total volume of the space between the first diffusion sheet, the second diffusion sheet and the oblique support sheet to the total volume of the diffusion plate is 5% to 90%.

In an embodiment of the invention, the first diffusion sheet is parallel to the second diffusion sheet.

In an embodiment of the invention, the diagonal support pieces are parallel to each other.

The direct type backlight module of the present invention includes a plurality of light sources and a diffusion plate as described above, wherein the diffusion plate is disposed above the light source.

Based on the above, in the diffusing plate proposed by the present invention, the oblique supporting piece has a high reflectance, so that the light entering the diffusing plate can be reflected multiple times between adjacent oblique supporting pieces, thereby achieving uniform light. Effect. In this way, the direct type backlight module proposed by the present invention can provide a uniform surface light source.

The above described features and advantages of the invention will be apparent from the following description.

100, 100’, 230‧‧‧ diffuser

110‧‧‧First diffuser

120‧‧‧Second diffusion film

130, 130'‧‧‧ diagonal support

130a‧‧‧ first side

130b‧‧‧Second side

200‧‧‧Direct type backlight module

210‧‧‧Lightbox

220‧‧‧Light source

C‧‧‧ overlap

L‧‧‧ connection line

PL, PR‧‧‧ orthographic projection

P1, P2‧‧‧ connection points

S‧‧‧ Space

Θ‧‧‧ angle

1 is a schematic cross-sectional view of a diffuser plate in accordance with an embodiment of the present invention.

2 is a top plan view of the orthographic projection of two oblique support sheets on the first diffusion sheet of FIG. 1.

3 is a schematic cross-sectional view of a diffuser plate in accordance with another embodiment of the present invention.

4 is a cross-sectional view of a direct type backlight module in accordance with an embodiment of the present invention.

In the present specification, the range represented by "a value to another value" is a schematic representation that avoids enumerating all the values in the range in the specification. Therefore, the recitation of a particular range of values is intended to include any value in the range of values and the range of values defined by any value in the range of values, as in the specification. The scope is the same.

1 is a schematic cross-sectional view of a diffuser plate in accordance with an embodiment of the present invention.

Referring to FIG. 1 , the diffusion plate 100 includes a first diffusion sheet 110 , a second diffusion sheet 120 , and a plurality of oblique support sheets 130 . The diagonal support piece 130 has opposite first side edges 130a and second side edges 130b. The first side 130a is connected to the first diffusion sheet 110, and the second side 130b is connected to the second diffusion sheet 120. That is, the oblique support piece 130 connects the first diffusion sheet 110 and the second diffusion sheet 120 together.

In addition, the oblique support sheet 130 has a higher reflectance than the first diffusion sheet 110 and The reflectance of the second diffusion sheet 120. For example, the reflectance of the oblique support piece 130 is 80% to 100%, and the transmittance of the first diffusion piece 110 and the second diffusion piece 120 is 75% to 90%. In this embodiment, since any two adjacent oblique supporting pieces 130 overlap each other, most of the light passing through the first diffusion sheet 110 is reflected or refracted by the oblique supporting piece 130 to reach the first stage. The two diffusion sheets 120 make the traveling direction of the light more diverse. At the same time, the oblique support piece 130 has a high reflectance, whereby the light entering the diffusion plate 100 can be reflected multiple times between the adjacent oblique support pieces 130, thereby achieving the effect of homogenizing the light. Therefore, the diffusion plate 100 of the present embodiment can increase the length of the current light path in a very thin overall thickness, providing an excellent light diffusion effect.

Since the first diffusion sheet 110 and the second diffusion sheet 120 have higher penetration than the oblique support sheet 130, light can smoothly enter the diffusion plate 100 and reflect between the oblique support sheets 130 or After the refraction, it can also be smoothly emitted from the diffusion plate 100.

The first diffusion sheet 110 and the second diffusion sheet 120 of the present embodiment are exemplified in parallel with each other, and the oblique support sheets 130 are also parallel to each other as an example, but the present invention is not limited thereto. In the present embodiment, the oblique support piece 130 is, for example, a rectangular sheet, and the first side 130a and the second side 130b are respectively opposite long sides of the rectangular sheet. In one embodiment, the first diffusion sheet 110 and the second diffusion sheet 120 have a thickness of 0.5 mm, the oblique support sheet 130 has a thickness of 0.1 mm, and the first diffusion sheet 110 is connected to the first side 130a. The distance between the surfaces to which the second diffusion sheet 120 is joined to the second side 130b is 4.0 mm.

In addition, the orthographic projections of any two adjacent oblique support sheets 130 on the first diffusion sheet 110 overlap each other. In other words, any two adjacent diagonal support pieces 130 may overlap each other. In detail, as shown in FIG. 1, the orthographic projection PL and the orthographic projection PR of the adjacent oblique supporting sheets 130 on the first diffusion sheet 110 overlap each other and have an overlapping portion C. In order to more clearly explain the overlapping relationship between the orthographic projection PL of the adjacent oblique supporting piece 130 on the first diffusion sheet 110 and the orthographic projection PR, reference is made hereinafter to FIG. 2 is a top plan view of the orthographic projection PL and the orthographic projection PR on the first diffusion sheet 110.

Referring to FIG. 1 and FIG. 2 simultaneously, the region of one of the orthogonal projections PL and the region of one of the orthographic projections PR completely overlap each other to form an overlapping portion C (hatched region). For example, the ratio of the area of the overlapping portion C to the area of the orthographic projection PL or the orthographic projection PR is 5% to 90%, but the present invention is not limited thereto. In the present embodiment, the shape of the orthographic projection PL and the orthographic projection PR is a rectangle, so the ratio of the area of the overlapping portion C to the area of the orthographic projection PL or the orthographic projection PR is the length of the short side of the overlapping portion C and the orthographic projection PL or The ratio of the length of the short side of the orthographic projection PR. In an embodiment, the length of the short side of the orthographic projection PL or the orthographic projection PR is 6.2 mm, and the length of the short side of the overlapping portion C is 1.4 mm.

In addition, although FIG. 1 illustrates that the ratio of the area of the overlapping portion C of any two adjacent oblique supporting sheets 130 on the first diffusion sheet 110 is the same as the ratio of the area of the orthographic projection PL or the orthographic projection PR, the present invention Not limited to this. In other embodiments, the ratio of the area of the overlapping portion C of any two adjacent oblique supporting sheets 130 on the first diffusion sheet 110 may be different from the ratio of the area of the orthographic projection PL or the orthographic projection PR.

In addition, in the cross section perpendicular to the first diffusion sheet 110 and the oblique support sheet 130 as shown in FIG. 1, the connection point P1 and the second of the first side 130a of the oblique support piece 130 and the first diffusion sheet 110 are second and second. The connection point P2 of the side edge 130b and the second diffusion sheet 120 may constitute a connection line L, and the angle θ of the connection line L and the first diffusion sheet 110 is, for example, 10 to 40 degrees, but the invention is not limited thereto. . In one embodiment, the included angle θ is 39.8 degrees. Since the oblique support piece 130 and the first diffusion piece 110 in the embodiment are both in a flat plate instead of having a curvature, the angle between the oblique support piece 130 and the first diffusion piece 110 is an angle θ. .

In addition, the ratio of the total volume of the space S between the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130 to the entire volume of the diffusion plate 100 may be 5% to 90%, but the present invention does not Limited to this. In detail, herein, "the overall volume of the diffusion plate 100" is defined as the first diffusion sheet 110 and the second in the case where the oblique support piece 130 is excluded between the first diffusion sheet 110 and the second diffusion sheet 120. The volume of the space in which the diffuser 120 is commonly defined between each other.

In the present embodiment, the components of the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130 include a resin and a light diffusing agent, wherein the light diffusing agent may be added to the resin to make the diffusing plate 100 have good light. Diffusion atomization function.

The resin includes a (meth) acrylate resin, a polystyrene resin, a polycarbonate resin, a methyl methacrylate-styrene copolymer, an acrylonitrile-styrene copolymer, and polyethylene terephthalate. Polyethylene terephthalate (PET), cyclo-olefin copolymer, polyolefin copolymer (such as poly-4-methylpentene-1), polyester, polyethylene, polypropylene, polyvinyl chloride Ionomer (ionomer) and so on. The above-mentioned (meth) acrylate-based resin is a polymer formed of a (meth) acrylate-based monomer, for example, polymethyl methacerylate (PMMA), and the above (meth)acrylic acid. Specific examples of the ester monomer include monomers such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl acrylate, methyl acrylate, ethyl acrylate, and isopropyl acrylate. Further, as the resin for manufacturing the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130, various commercially available products can be used. Examples of commercially available products suitable for use as the resin include: (meth) acrylate-based resin such as CM205X (manufactured by Chi Mei Co., Ltd.); polycarbonate resin such as PC-110D (manufactured by Chi Mei Co., Ltd.).

The light diffusing agent includes inorganic fine particles and organic fine particles, wherein the inorganic fine particles are, for example, fine particles such as barium sulfate (BaSO ₄ ) or titanium dioxide (TiO ₂ ); and the organic fine particles are, for example, polystyrene resin, (meth)acrylic resin, organic Rack bridge microparticles formed by a siloxane resin or the like. Further, these light diffusing agents may be used singly or as a mixture of two or more of them. The average particle diameter of the light diffusing agent is preferably from 0.1 μm to 20 μm. Further, as the light diffusing agent, various commercially available products can also be used. Examples of commercially available products suitable for use as a light diffusing agent include: SI-020 (manufactured by GANZ Corporation), Tospearl 120 (product of GE TOSHIBA SILICONE), KMP-590 (product of Shin-Etsu Corporation of Japan), CR-95 (by 堺A chemical company, A-45 (manufactured by Daicel Chemical Co., Ltd.).

In addition, the weight percentage of the light diffusing agent in the first diffusion sheet 110 and the second diffusion sheet 120 is lower than the weight percentage of the light diffusing agent in the oblique supporting sheet 130. Specifically, the weight of the light diffusing agent in the first diffusion sheet 110 and the second diffusion sheet 120 The percentage by weight is from 1% by weight to 15% by weight, preferably from 1% by weight to 10% by weight, and the weight percentage of the light diffusing agent in the oblique supporting sheet 130 is from 15% by weight to 30% by weight. In one embodiment, the components of the first diffusion sheet 110 and the second diffusion sheet 120 include a polycarbonate resin PC-110D and a light diffusing agent SI-020, wherein the light diffusing agent SI-020 has a weight percentage of 10%. And the components of the diagonal support sheet 130 include a polycarbonate resin PC-110D and a light diffusing agent CR-95, wherein the light diffusing agent CR-95 has a weight percentage of 20%.

Further, in the present embodiment, the method of manufacturing the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130 is carried out by performing a co-extrusion process using a co-extrusion molding apparatus having a profiled extrusion die. In detail, the co-extrusion forming device comprises at least two extruding machines, wherein the extruding machine may be a uniaxial extruder or a two-axis extruding machine. The profiled die can be provided with a lip having a desired specific shape, depending on the needs of the product. In an embodiment, the co-extruding process includes the following steps. First, the resin and the light diffusing agent which are to form the first diffusion sheet 110 and the second diffusion sheet 120 are poured from the inlet portion of one extruder, and the resin and the light diffusing agent which are to form the oblique support sheet 130 are Pour the entrance of the extruder. Next, after heating each of the above-mentioned raw materials, they were melted and kneaded, and co-extruded through a die-shaped extrusion die, and directly introduced into a vacuumed sizing apparatus to obtain a diffusion plate 100.

In the foregoing embodiment, since the raw materials of the first diffusion sheet 110 and the second diffusion sheet 120 are melt-kneaded by the same extruder, the first diffusion sheet 110 and the second diffusion sheet 120 have the same composition after extrusion molding. And the proportion. however, The invention is not limited to this. In other embodiments, the raw materials of the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130 may be melt-kneaded by different extruders (ie, the co-extrusion molding apparatus includes three extruders). That is to say, in the foregoing case, the types of components in the first diffusion sheet 110 and the second diffusion sheet 120 may be different, or the light diffusion agent in the first diffusion sheet 110 and the second diffusion sheet 120 may be added. The ratio can be different.

In addition, in the present embodiment, the first diffusion sheet 110, the second diffusion sheet 120, and the oblique support sheet 130 may be surface-treated by a roller as needed to form a fine structure of the unevenness on the surface or The surface is flattened and can also be used as described in Taiwan Patent No. I382203, which is incorporated herein by reference.

Further, although in the embodiment of Fig. 1, the diagonal supporting pieces 130 are parallel to each other, the present invention is not limited thereto. In other embodiments, the obliquely supported sheets at high temperatures may be deformed after extrusion forming such that the plurality of diagonally facing sheets in the diffuser plate do not exhibit parallel to each other. For example, please refer to FIG. 3 and FIG. 1 at the same time, the diffusion plate 100 ′ of FIG. 3 is different from the diffusion plate 100 of FIG. 1 only in that the oblique support piece 130 ′ in the diffusion plate 100 ′ is a sheet having a curved surface. And the diagonal support pieces 130 in the diffusion plate 100 are rectangular sheets which are disposed in parallel with each other.

4 is a cross-sectional view of a direct type backlight module in accordance with an embodiment of the present invention.

Referring to FIG. 4 , the direct type backlight module 200 includes a light box 210 and a plurality of lights. Source 220 and diffusion plate 230. The light source 220 is disposed in the light box 210. In the present embodiment, the light source 220 is a point light source arranged in an array. For example, these point sources are, for example, light-emitting diodes. However, the invention is not limited thereto. In other embodiments, the light source 220 can also be a line source, such as a cold cathode fluorescent tube.

The diffusion plate 230 is disposed above the light sources 220. In the present embodiment, the diffusion plate 230 is realized by the diffusion plate 100 of FIG. Since the materials, manufacturing methods, and effects of the respective members in the diffusion plate 100 have been described in detail in the above embodiments, the diffusion plate 230 will not be described here.

Further, as described above, since the diffusing plate 100 of the present invention includes a plurality of oblique supporting pieces 130 which overlap each other with each other, and the oblique supporting piece 130 has a high reflectance, the light source 220 provides After entering the diffusing plate 100, the light can be reflected multiple times between the adjacent oblique supporting pieces 130, thereby achieving the effect of uniformizing the light. In this way, the direct type backlight module 200 of the present invention can provide a uniform surface light source without increasing the distance between the light source 220 and the diffusion plate 100 or increasing the amount of the light source 220 used.

On the other hand, since the first diffusion sheet 110 and the second diffusion sheet 120 have higher penetration than the oblique support sheet 130, the light provided by the light source 220 can smoothly enter the diffusion plate 100, and After the oblique support pieces 130 are reflected between each other, they can be smoothly emitted from the diffusion plate 100. As a result, the direct type backlight module 200 of the present invention has good light utilization efficiency.

In addition, although the above-described direct type backlight module of the present invention is described in detail with the diffusion plate 100 of FIG. 1, it should be understood by those skilled in the art that The diffusion plate 230 can also be realized by the diffusion plate 100 ′ of FIG. 3 , and the light-emitting path of the light provided by the light source 220 is increased by the plurality of oblique support pieces 130 ′ that overlap each other, and the embodiment can also be made. The direct type backlight module 200 provides a uniform light source.

As described above, in the diffusing plate proposed in the above embodiment, the plurality of oblique supporting pieces that overlap each other have higher reflectance than the first diffusing sheet and the second diffusing sheet, so that the entering The light of the diffusing plate can be reflected multiple times between the adjacent oblique supporting pieces, thereby achieving the effect of uniformizing the light without increasing the overall thickness of the diffusing plate. In this way, the direct type backlight module proposed in the above embodiment can provide a uniform surface light source.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of the invention is defined by the scope of the appended claims.

100‧‧‧Diffuser

110‧‧‧First diffuser

120‧‧‧Second diffusion film

130‧‧‧ diagonal support

130a‧‧‧ first side

130b‧‧‧Second side

C‧‧‧ overlap

L‧‧‧ connection line

PL, PR‧‧‧ orthographic projection

P1, P2‧‧‧ connection points

S‧‧‧ Space

Θ‧‧‧ angle

Claims (10)

A diffusion plate includes: a first diffusion sheet; a second diffusion sheet; and a plurality of oblique support sheets, wherein each of the oblique support sheets has a first side and a second side opposite to each other The first side is connected to the first diffusion sheet, and the second side is connected to the second diffusion sheet, and the orthographic projections of the two adjacent oblique support sheets on the first diffusion sheet overlap each other, and The reflectance of the diagonal support sheets is higher than the reflectance of the first diffusion sheet and the second diffusion sheet. The diffusing plate according to claim 1, wherein an area of the overlapping portion of the two adjacent ones of the oblique supporting sheets on the first diffusing sheet is opposite to any of the adjacent oblique directions The ratio of the area of the orthographic projection of one of the support sheets on the first diffusion sheet is 5% to 90%. The diffusion plate of claim 1, wherein the first side of the oblique support piece and the first diffusion are in a cross section perpendicular to the first diffusion piece and the diagonal support pieces The connection point of the sheet and the connection point of the second side and the second diffusion sheet form a connecting line, and the angle between the connecting line and the first diffusion sheet is 10 to 40 degrees. The diffusion plate of claim 1, wherein the first diffusion sheet and the second diffusion sheet have a transmittance of 75% to 90%. The diffusing plate of claim 1, wherein the oblique supporting sheets have a reflectance of 80% to 100%. The diffusing plate according to claim 1, wherein a weight percentage of the light diffusing agent in the components of the first diffusing film and the second diffusing film is lower than a light diffusing agent in the components of the diagonal supporting sheets Percentage of weight. The diffusion plate according to claim 1, wherein a ratio of a volume of the space between the first diffusion sheet, the second diffusion sheet and the oblique support sheets to a whole volume of the diffusion plate is 5% to 90%. The diffusing plate of claim 1, wherein the first diffusing sheet is parallel to the second diffusing sheet. The diffusing plate of claim 1, wherein the diagonal supporting pieces are parallel to each other. A direct-lit backlight module comprising: a plurality of light sources; and a diffusing plate according to any one of claims 1 to 9 disposed above the light sources.