TWI481909B - Diffuser, backlight module and display device - Google Patents

Description

Diffusion plate, backlight module and display device

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a diffusing plate, and more particularly to a diffusing plate having a tapered shape with mutually different shapes on the surface, and a backlight module and a display device using the diffusing plate.

Liquid crystal display technology has been widely used in various fields, such as televisions, portable devices, digital cameras and computer screens. However, since the liquid crystal display itself does not emit light, it is necessary to display an image by means of a light-emitting device or a "backlight module" from the back.

Traditionally, the backlight module uses a cold cathode lamp as its light source. However, in view of the many advantages of the light-emitting diode, there seems to be a tendency to replace the cold cathode lamp with a light-emitting diode. However, regardless of the light source used, the light uniformity of the backlight module must meet the display requirements of the liquid crystal display module. Therefore, if a backlight module using a light-emitting diode as a light source, how to make the light emission of the light-emitting diode uniform is one of the important topics in development.

FIG. 1 shows a conventional LED backlight module 10 of the prior art. In order to uniformly provide the illuminating energy of the illuminating diode 11 to the display module, it is achieved by using the diffusing plate 12 and the optical film set 14 disposed above the diffusing plate 12, wherein the diffusing plate 12 may have a plurality of surfaces on the surface thereof. a pyramid-shaped recess for facilitating the divergence of light within the diffuser panel 12, the optical film set 14 may comprise more than one optical film, such as a brightness enhancement sheet, a diffusion sheet, a reflective polarization addition sheet, or the above-mentioned film group combination. However, the light emitting uniformity of the light emitting diode 10 of the backlight module is a light emitting diode 11 from the influence of the ratio D _1, etc. The distance W is 11 and a diffusion plate ₁ and the light emitting diode 12, and this impact The number of uses of the diffusion plate 12 is determined. That is, if W ₁ /D _{1 is} less than or equal to 1.25, then only one diffusion plate 12 is sufficient to homogenize the light; if W ₁ /D _{1 is} greater than 1.25, two diffusion plates 12 and 13 are required. The display module is evenly illuminated, even two or more diffusers.

However, with the demand for energy saving, the number of use of the light-emitting diodes 11 will be reduced, and in the case of using the same size display module, the distance W ₁ between the light-emitting diodes 11 will necessarily increase. When the pitch is increased such that W ₁ /D ₁ exceeds 1.25, in order to maintain a certain degree of uniformity of illumination, two sheets of diffusion plates 12 and 13 must be used. Although increasing the number of the diffusion plates 12 and 13 makes the light emission uniform, as the amount of the diffusion plates 12 and 13 increases, the cost of the light-emitting diode backlight module 10 also increases.

In summary, the current LED backlight module utilizes a diffusion plate and an optical film set placed above the diffusion plate to achieve light homogenization, although the diffusion plate can be configured with a plurality of pyramids for helping light to diverge. The concave portion of the shape, however, is not sufficient to solve the effect on the uniformity of light after the geometrical ratio between the light-emitting diodes or between the light-emitting diodes and the diffusing plate is changed. Therefore, this aspect still needs the development of new technologies.

The invention provides a diffusing plate, and a backlight module and a display device using the diffusing plate, wherein the diffusing plate utilizes different sizes and cross-arranged microstructures and hair lines to reduce light-emitting diodes or light-emitting diodes and The effect on the uniformity of light caused by the geometrical ratio between the diffusers.

A first diffusion plate according to an embodiment of the invention comprises a light incident surface and a light Corresponding to the light exit surface of the light incident surface, the light exit surface comprises a plurality of periodic structures. The periodic structures are arranged on the light-emitting surface so that a plurality of pyramid-shaped concave portions arranged in a row and a row are formed on the light-emitting surface. Each periodic structure includes one or a plurality of identical or plural different main linear convex arrangement combinations combined with one or a plurality of identical or plural different secondary linear convex portions, wherein the main linear convex portion and the secondary line The convex portions are arranged side by side. The cross-section of the main linear protrusion and the sub-linear protrusion is angular, so that a plurality of pyramid-shaped recesses arranged in a row and a row are formed on the light-emitting surface. The height of the main linear protrusion is greater than the height of the linear protrusion.

A first backlight module according to an embodiment of the invention comprises a substrate, a plurality of light emitting diodes, a first diffusion plate and an optical film group as described above. A matrix of light emitting diodes is arranged on the substrate. The diffuser plate system is disposed on the light emitting diode. The optical film set is disposed on the diffusion plate.

A first display device according to an embodiment of the invention comprises a first backlight module and a display panel as described above. The display panel is disposed on the backlight module.

A second diffusing plate according to an embodiment of the invention comprises a light incident surface, a light exiting surface, a main linear convex portion and a primary linear convex portion. The light incident surface corresponds to the light exit surface. The main linear protrusion is disposed on the light exit surface and has a main apex angle θ ₁ and a main height H ₁ . The linear convex portion is disposed on the light emitting surface and adjacent to the main linear convex portion, and has a primary apex angle θ ₂ and a primary height H ₂ , wherein the primary apex angle θ _{1 is} greater than the secondary apex angle θ ₂ , and the main height H _{1 is} greater than the secondary height H ₂ .

A third diffusing plate according to an embodiment of the present invention includes a light incident surface, a light exiting surface, a plurality of main linear convex portions, and a plurality of secondary linear convex portions. The light incident surface corresponds to the light exit surface. A plurality of main line-like convex portions are disposed on the light-emitting surface, and one of the main linear convex portions has a main height H ₁ and a main base length L ₁ , and 0.3<H ₁ /L ₁ <0.4. a plurality of sub-linear convex portions are disposed on the light-emitting surface, and one of the plurality of linear convex portions is adjacent to the main linear convex portion, and has a primary height H ₂ and a primary base length L ₂ , and 0.4 ≦ H ₂ /L ₂ ≦0.7, wherein the main height H _{1 is} greater than the secondary height H ₂ .

A second backlight module according to an embodiment of the invention comprises a substrate, a plurality of light emitting diodes, the second diffusion plate or the third diffusion plate and the optical film group. The light emitting diodes are arranged on the substrate, and the spacing between the adjacent light emitting diodes is W ₁ . The second diffusing plate or the third diffusing plate is configured to correspond to the light emitting diodes, wherein the distance between the diffusing plate and the light emitting diodes is D ₁ and 1.25<W ₁ /D ₁ <1.5. The optical film set is provided corresponding to the aforementioned second diffusion plate or the aforementioned third diffusion plate.

A second display device according to another embodiment of the present invention includes a second backlight module and a display panel as described above. The display panel corresponds to the backlight module configuration.

2 is a perspective view showing a diffusion plate 20 according to an embodiment of the present invention. Figure 3 shows a plan view of a diffuser panel 20 in accordance with an embodiment of the present invention. The diffusing plate 20 disclosed in the present invention comprises a light emitting surface 21, a light incident surface 22, a plurality of main linear convex portions 23, and a plurality of linear linear convex portions 24. The light incident surface 22 is disposed opposite to the light exit surface 21 . The main line-like convex portions 23 and the sub-linear convex portions 24 have different apex angles and heights, and form a periodic structure in a periodic arrangement, and emit light in two directions (x direction and y direction). The surface 21 is cross-arranged, wherein the two directions may be vertical or sandwiched by a predetermined angle, and the invention is not limited thereto. The sub-linear protrusions 24 have a smaller apex angle so that the light can be dispersed to a farther position, and the main line-like protrusions 23 can disperse the light to a closer position. By using the combination of the main linear protrusions 23 and the sub-linear protrusions 24, the ability to disperse light can be increased, thereby solving the problem that when W ₁ /D ₁ exceeds 1.25, it is impossible to achieve using only a single diffusion plate 20 The problem of uniform dispersion of light, particularly when 1.25 < W ₁ / D ₁ < 1.5, requires only one diffusion plate 20 to be used, and the effect of the conventional two diffusion sheets 12, 13 can be achieved. By arranging the main linear convex portions 23 and the sub-linear convex portions 24 having different apex angles and heights, the sub-linear convex portions 24 having weak structural strength can obtain main linear convex portions having strong structural strength. The protection of 23 increases the durability of the diffuser panel 20.

The cross-section of each of the main linear protrusions 23 and each of the sub-linear protrusions 24 is angular, and the main linear protrusions 23 and the sub-linear protrusions 24 are adjacently arranged. Therefore, a plurality of pyramid-shaped recesses 25 arranged in a matrix and having different shapes are formed on the light-emitting surface 21.

3 is a top view of a diffuser plate 20 according to an embodiment of the present invention; FIG. 4 is a partial enlarged view of a portion A of FIG. 3; FIG. 5 is a cross-sectional view taken along line 1-1 of FIG. Fig. 6 is a cross-sectional view taken along line 2-2 of Fig. 4 (in the y direction). The periodic structure 50 (shown in FIG. 5) includes a main linear protrusion 23 and a primary linear protrusion 24. In the embodiment of the present invention, the periodic structure 50 includes a main linear convex portion 23 and two secondary linear convex portions 24a and 24b, wherein the main linear convex portion 23 is higher than the secondary linear convex portions 24a and 24b. The two sub-line-like convex portions 24a and 24b may be the same (as shown in Fig. 5). In the present invention, the heights of the main linear convex portion 23 and the secondary linear convex portion 24b are required to satisfy some conditions, and the heights of the main linear convex portion 23 and the secondary linear convex portion 24b can be set using a reference line 54. The reference line 54 is a virtual reference line for comparing the difference between the main linear protrusions 23 and the secondary linear protrusions 24, so that it can be selected according to actual needs, and the invention is not limited thereto. If the line connecting the bottom 51a of the pyramid-shaped recess 25a and the bottom 51d of the pyramid-shaped recess 25d is selected as the reference line 54, the height of the main linear protrusion 23 can be from the top 52 of the main linear protrusion 23 to the reference line 54. the height H _{represented. 1;} and the top 24b of the height of the linear projection views may be views of the linear convex portion 24b to the reference line 53b ₂ of a height H 54 is represented, wherein this two highly preferred in the present invention satisfies H ₁ -H ₂ >1 μm, and conditions such as H ₁ -H ₂ <H ₂ /5.

In the present invention, other geometrical dimensions of the main linear protrusions 23 and the secondary linear protrusions 24a, 24b are also limited. Referring to Fig. 5, the main linear protrusion 23 has an angular cross section having a main apex angle θ ₁ ; the cross sections of the sub linear protrusions 24a and 24b are also angular, having a primary apex angle θ ₂ , wherein θ ₁ and θ ₂ need to satisfy the condition of θ ₁ &gt _; θ ₂ . In one embodiment, θ ₁ may be between 102° and 119°; and θ ₂ may be between 70° and 103°. In another embodiment, θ ₁ and θ ₂ need to satisfy θ ₂ <90°. The condition of θ ₁ , that is, the main apex angle θ _{1 is} greater than or equal to 90°, and the minor apex angle θ ₂ is less than 90°.

Referring to Fig. 5, the length of the base portion of the main linear convex portion 23 is L ₁ ; the length of the base portion of the secondary linear convex portions 24a and 24b is L ₂ , where L _{1 is} larger than L ₂ . Furthermore, the ratio of the height H ₁ of the main linear convex portion 23 to the length of the base portion L ₁ is required to be less than 0.4, that is, H ₁ /L ₁ <0.4, and in one embodiment, the top height H ₁ and the base portion The ratio of the ratio of length L ₁ may be between 0.3 and 0.4, that is, 0.3 < H ₁ / L ₁ < 0.4. The ratio of the height H _{2 of} each linear convex portion 24b to the length of the base portion L ₂ is required to be greater than or equal to 0.4, that is, H ₂ /L ₂ ≧ 0.4, and in one embodiment, the top height H ₂ and the base portion The ratio of the length of L ₂ may range between 0.4 and 0.7, i.e., 0.4 ≦ H ₂ / L ₂ ≦ 0.7.

Referring to Fig. 5, the bottom portions 51b and 51c of the pyramid-shaped recesses 25b and 25c in the periodic structure 50 are generally not seated on the same reference line 54 at the time of fabrication. In this way, the vertical distances H ₁ and H of the bottom portion 51a and the bottom portion 51b on both sides of the main linear convex portion 23, the laterally corresponding pyramid-shaped concave portion 25a and the pyramid-shaped concave portion 25b, and the top portion 52b of the main linear convex portion 23 are located. ₁ 'different. In the embodiment of the present invention, the top portion 52 of the main linear convex portion 23 is located between the pyramidal concave portion 25a corresponding to the lateral direction of the main linear convex portion 23 and the bottom portion 51a and 51b of the pyramidal concave portion 25b. The difference does not exceed one-fifth of the height of the main linear convex portion 23 (the vertical distance from the top 52 of the main linear convex portion 23 to the reference line 54; H ₁ ), that is, | H ₁ -H ₁ '|<H ₁ / 5. Further, the top portion 53b of the sub-linear convex portion 24b is located between the bottom portion 51c of the pyramid-shaped concave portion 25c and the bottom portion 51d of the pyramid-shaped concave portion 25d which are located on both sides of the sub-linear convex portion 24b, and the bottom portion 51d of the pyramid-shaped concave portion 25d. Less than one fifth of the height of the secondary linear convex portion 24b (the vertical distance from the top 53b of the secondary linear convex portion 24b to the reference line 54; H ₂ ), that is, | H ₂ -H ₂ '|<H ₂ /5 . When H ₁ '>H ₁ and H ₂ '>H ₂ , the top portion 53a of the secondary linear protrusion 24b can be made more than the bottom portions 51b and 51c of the pyramidal recesses 25b and 25c on both sides. protruding. However, in other embodiments, | H ₁ -H ₁ '| or | H ₂ -H ₂ '| may be minimized to zero, to avoid individual main linear protrusions 23 or sub-linear protrusions 24 The difference between the two is too large to grasp the uniformity of the luminance. Similarly, the relationship between the vertical distance differences may be applied to the other side of the main linear protrusion 23 or the secondary linear protrusion 24, and the invention is not limited thereto.

Referring to Figure 6, Figure 6 shows a cross-sectional view in the y-direction. In this embodiment, since the periodic structure 50 arranged in the y direction is the same as the x direction, the related dimensions and required conditions are the same as those of the periodic structure 50 of FIG. 5, and therefore will not be described again.

FIG. 7 is a schematic view showing the light incident surface 22 of the diffuser panel 20 according to an embodiment of the present invention. The light incident surface 22 of the diffuser panel 20 may be provided with a hairline 71. The hairline 71 will form the surface of the mold of the diffusing surface 20 of the diffusing plate 20, and the grinder generates a plurality of stripe strips which are approximately parallel in one direction, and the diffusing plate 20 is formed on the light-incident surface 22 after the fabrication is completed. The line stripe is transferred to form the hairline 71 arranged in a horizontal direction (x direction) and extending in the other horizontal direction (y direction). In one embodiment, the center line average roughness Ra is measured perpendicular to the y direction, that is, the center line average roughness Ra is measured along the x direction, and the center line average roughness Ra is measured to be in the range of 0.002. Between microns and 2 microns. In addition, by adjusting the numerical value of the center line average roughness Ra of the hairline, the light dispersion ability perpendicular to the direction in which the hairline extension is arranged (y direction) can be adjusted, and the light dispersion ability in the x direction can be adjusted. The larger the value of the line average roughness Ra, the closer the light dispersion distance is; and in the embodiment of the present invention, the roughness of the hairline pattern 71 may be between 0.5 micrometers and 0.6 micrometers.

8A to 8C are views showing the effect of homogenizing a diffusion plate according to an embodiment of the present invention. Referring to FIG. 8A, a plurality of light emitting diode matrices are arranged in a light emitting diode array 80, and the distance between adjacent light emitting diodes is approximately Also, for example, the distance can be 30 cm.

Referring to FIG. 8B, a diffusion plate 20 provided with a periodic structure 50 as shown in the embodiment of FIG. 5 is placed on the LED array 80 shown in FIG. 8A because the periodic structure 50 includes a main linear protrusion 23 and The two linear convex portions 24a and 24b, wherein the main linear convex portion 23 is higher than the secondary linear convex portions 24a and 24b, and the apex angle of the main linear convex portion 23 is larger than the secondary linear convex portions 24a and 24b. For this reason, the light emission of each light-emitting diode is polymerized to different positions, so that four light spots can be formed between adjacent light-emitting diodes, thereby achieving the purpose of homogenizing the light, the number of light spots and the main line. The apex angles of the convex portions 23 and the sub-linear convex portions 24a and 24b are not necessarily four. The light spot corresponding to each light-emitting diode has a diameter similar to that of four light spots between adjacent light-emitting diodes, but the brightness is low.

Referring to FIG. 8C, a diffusing plate having a periodic structure 50 as shown in the embodiment of FIG. 5 and a hairline 71 as shown in FIG. 7 on the light-incident surface is disposed on the light-emitting surface of the light-emitting diode shown in FIG. 8A. After the array 80, in addition to the above results produced by the periodic structure 50, the hairline 71 can cause the light emission of the light emitting diode and the light of each light spot shown in FIG. 8B to be diffused in the vertical direction of the hairline 71, and finally form. As shown in FIG. 8C, in the optical image of the mesh structure, in the optical image of the mesh structure, the intersection of the straight direction and the lateral light and shadow is the location of the light emitting diode. If the optical film set is applied to the diffusion plate, the optical film group can further homogenize the optical image of the mesh structure, and finally achieve a good result of the Just Noticeable Difference (JND) 1.8. . That is, when the perceptible difference of a device is greater than 2, the brightness of the device can be easily recognized by the naked eye of the average person, and when the device is perceived to be poor, When the difference is less than 2, although the device actually has a non-uniform phenomenon, it has reached an extent that the naked eye cannot recognize. Therefore, the periodic structure 50 disclosed in the present invention can be combined with the hairline 71 to obtain good light uniformity. The effect of the transformation.

9 through 11 show schematic cross-sectional views of periodic structures 50a-50c of other embodiments of the present invention. Referring to Fig. 9, the main linear protrusions 23a and 23b and the sub-linear protrusions 24c included in the periodic structure 50a may have different shapes. In the embodiment of FIG. 9, in the main linear convex portion 23a, the two side faces 93 or other side faces of the side clamp main apex angle θ may be convex surfaces and sub-linear convex portions, in addition to the plane shown in the embodiment of FIG. The side of the 24c can also be convex. Furthermore, the periodic structure 50a may include two main linear convex portions 23a and 23b and a primary linear convex portion 24c, wherein the secondary linear convex portion 24c is interposed between the two main linear convex portions 23a and 23b. By arranging the structure of the periodic structure 50a, the result of the adjacent two main linear protrusions 23a, 23b can be obtained. Referring to Figures 10 and 11, the side faces or other sides of the main linear projections 23c and 23d and the secondary linear projections 24d and 24e may be respectively formed into a concave surface (as shown in Fig. 10) or a continuous concave-convex surface (Fig. 11). Shown).

FIG. 12 shows a schematic diagram of a display device 120 in accordance with an embodiment of the present invention. The display device 120 includes a display panel 122 for providing a display image and a backlight module 121 for providing a light source of the display panel 122. The backlight module 121 includes a substrate 123, a plurality of LEDs 124 arranged on the substrate 123, a diffusion plate 125 disposed on the LEDs 124, and one of the diffusion plates 125. The optical film set 126 and a reflective sheet 127. The substrate 123 can be a circuit board for providing the power required for the LEDs 124, or a general metal/plastic board, for the power supply of the LEDs 124 to pass through without directly provide. The reflective sheet 127 is also disposed on the substrate 123. The light-emitting diodes 124 are penetrated or located between or adjacent to the light-emitting diodes 124. Preferably, they may be white reflective sheets. The light-emitting surface of the diffusing plate 125 facing the optical film group 126 includes the above-mentioned periodic structure, and the periodic structure is arranged to intersect with the light-emitting surface, so that a plurality of pyramid-shaped concave portions arranged in a row and a row are formed on the light-emitting surface. The periodic structure includes one or several identical or a plurality of different main linear convex arrangement combinations arranged side by side in combination with one or several identical or a plurality of different sub linear convex portions. The light-emitting surface of the diffusing plate 125 facing the light-emitting diode 124 may be provided with the aforementioned hairline. By using the periodic structure and the hairline, the backlight module 121 can be prevented from being uneven in illumination due to an increase in the distance between the light-emitting diodes 124 or a decrease in the height of the diffusion plate 125 to the light-emitting diodes 124.

The technical and technical features of the present invention have been disclosed as above, and those skilled in the art can still make various substitutions and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims

10‧‧‧Lighting diode backlight module

11‧‧‧Lighting diode

12, 13‧‧‧ diffuser board

14‧‧‧Optical diaphragm group

20‧‧‧Diffuser

21‧‧‧Glossy

22‧‧‧Into the glossy surface

23, 23a, 23b, 23c, 23d‧‧‧ main line convex

24, 24a, 24b, 24c, 24d, 24e‧‧‧ times linear protrusions

25, 25a, 25b, 25c, 25d‧‧‧ pyramidal recesses

50, 50a, 50b, 50c‧‧‧ periodic structure

51a, 51b, 51c, 51d‧‧‧ bottom

52, 53a, 53b‧‧‧ top

54‧‧‧ baseline

71‧‧‧ hairline

80‧‧‧Lighting diode array

93‧‧‧ side

120‧‧‧ display device

121‧‧‧Backlight module

122‧‧‧ display panel

123‧‧‧Substrate

124‧‧‧Lighting diode

125‧‧‧Diffuser

126‧‧‧Optical diaphragm group

127‧‧‧reflector

1 shows a light-emitting diode backlight module of the prior art; FIG. 2 shows a partial perspective view of a diffuser plate according to an embodiment of the present invention; FIG. 3 shows a top view of the diffuser plate of FIG. 2; FIG. 5 is a cross-sectional view taken along line 1-2 of FIG. 4; FIG. 6 is a cross-sectional view taken along line 2-2 of FIG. 4; and FIG. 7 shows light entering the diffusing plate according to an embodiment of the present invention. Schematic diagram 8A to 8C are views showing a homogenization effect of a diffusion plate according to an embodiment of the present invention; FIGS. 9 to 11 are schematic cross-sectional views showing a periodic structure of another embodiment of the present invention; and FIG. 12 is a view showing an embodiment of the present invention. Schematic diagram of the device.

20‧‧‧Diffuser

21‧‧‧Glossy

22‧‧‧Into the glossy surface

23‧‧‧Main linear protrusion

24‧‧‧ times linear protrusions

25‧‧‧ pyramidal recess

Claims (29)

a diffusing plate comprising: a light incident surface; and a light emitting surface corresponding to the light incident surface, comprising a plurality of periodic structures consisting of a main linear convex portion and a linear linear convex portion juxtaposed; wherein The main line-shaped convex portion and the sub-linear convex portion have an angular cross section, and the periodic structures are arranged on the light-emitting surface, so that a plurality of pyramid-shaped concave portions arranged in a row and a row are formed on the light-emitting surface, and The height of the main linear convex portion is larger than the height of the secondary linear convex portion, and the height difference between the main linear convex portion and the secondary linear convex portion is between 1 micrometer and the height of the secondary linear convex portion. Between the tops of the main linear protrusions and the bottoms of the pyramid-shaped recesses corresponding to the two sides of the main linear protrusions, the vertical distance difference between the two is smaller than the height of the main linear protrusions. one fifth. The diffusing plate according to claim 1, wherein an apex angle of the main linear convex portion is larger than an apex angle of the secondary linear convex portion. The diffusing plate according to claim 1, wherein a length of a base of a cross section of the main linear convex portion is larger than a length of a base of a cross section of the secondary linear convex portion. The diffusing plate according to claim 1, wherein a ratio of the height of the main linear convex portion to the base length of the cross section of the main linear convex portion is less than 0.4. The diffusing plate according to claim 1, wherein a ratio of the height of the main linear convex portion to the length of the base portion of the cross section of the main linear convex portion is between 0.3 and 0.4. The diffusing plate of claim 1, wherein the height of the linear protrusion is The ratio of the base length of the cross section of the linear protrusion is greater than or equal to 0.4. The diffusing plate according to claim 1, wherein a ratio of the height of the linear convex portion to the length of the base portion of the cross section of the secondary linear convex portion is between 0.4 and 0.7. The diffusing plate according to claim 1, wherein an apex angle of the main linear convex portion is greater than or equal to 90°, and an apex angle of the secondary linear convex portion is less than 90°. The diffusing plate according to claim 1, further comprising a hairline extending over the light incident surface, and a center line average roughness ranging from 0.002 micrometers to a direction perpendicular to the extending direction of the hairline Between 2 microns. The diffuser panel of claim 9, wherein the centerline average roughness ranges between 0.5 microns and 0.6 microns. The diffusing plate according to claim 1, wherein the side is sandwiched between the main linear convex portion and the side surface of the apex angle of the secondary linear convex portion, and includes a flat surface, a convex surface, a concave surface, and/or a continuous uneven surface. The diffusing plate according to claim 1, wherein a top of the linear convex portion is at a bottom portion of the pyramid-shaped concave portion corresponding to both sides of the linear convex portion and laterally corresponding to each other, and a vertical distance difference between the two is smaller than the time One-fifth of the height of the linear protrusion. A backlight module comprising: a substrate; a plurality of light emitting diodes arranged in a matrix on the substrate; the diffusing plate according to any one of claims 1 to 12, wherein the diffusing plate is disposed On the light emitting diode; The optical film set is disposed on the diffusion plate. A display device comprising: a backlight module as claimed in claim 13; and a display panel disposed on the backlight module. a diffusing plate comprising: a light incident surface; a light emitting surface corresponding to the light incident surface; a main linear convex portion disposed on the light emitting surface, having a main apex angle θ ₁ and a main height H ₁ ; And a linear convex portion disposed on the light emitting surface adjacent to the main linear convex portion, having a primary apex angle θ ₂ and a primary height H ₂ ; wherein the primary apex angle θ _{1 is} greater than the secondary apex angle θ ₂ And the main height H _{1 is} greater than the secondary height H ₂ , and the height difference between the main linear convex portion and the secondary linear convex portion is between 1 micrometer and one fifth of the height of the secondary linear convex portion The difference between the top of the main linear protrusion and the bottom of the main linear protrusion is less than one fifth of the main height of the main linear protrusion. The diffusing plate of claim 15, wherein the main apex angle θ ₁ ranges between 102° and 119°. The diffusing plate of claim 15, wherein the secondary apex angle θ ₂ ranges between 70° and 103°. The diffusing plate of claim 15, wherein the main apex angle θ _{1 is} greater than or equal to 90°, and the secondary apex angle θ _{2 is} less than 90°. The diffusing plate according to claim 15 further comprising a hairline pattern along the water The flat direction is extended on the light incident surface. The diffusing plate of claim 19, wherein the center line perpendicular to the horizontal direction has an average roughness ranging between 0.002 microns and 2 microns. A diffusing plate includes: a light incident surface; a light emitting surface corresponding to the light incident surface; a plurality of main linear convex portions disposed on the light emitting surface, one of the main linear convex portions having a main height H ₁ and a main base length L ₁ and 0.3<H ₁ /L ₁ <0.4; and a plurality of sub-linear convex portions disposed on the light-emitting surface, one of the sub-linear convex portions and the main linear shape The convex portion is adjacent to have a primary height H ₂ and a primary base length L ₂ and 0.4≦H ₂ /L ₂ ≦0.7; wherein the primary height H _{1 is} greater than the secondary height H ₂ , the primary height H ₁ and the The height difference of the secondary height H ₂ is greater than 1 micrometer and less than one fifth of the secondary height H ₂ , and the top of the main linear convex portions is located between the tops of the main linear convex portions and the bottom sides of the main linear convex portions. The distance difference is less than one fifth of the main height of the main linear protrusions. The diffusing plate of claim 21, wherein the main base length L _{1 is} greater than the sub-base length L ₂ . The requested item of the diffusion plate 21, wherein the amount of difference between these _main height H is less than the height H ₁ of the main one fifth. The requested item of the diffusion plate 21, wherein the amount of difference between these _two times the height H is less than ₂ times the height H of one-fifth. The diffusing plate according to claim 21, further comprising a hairline pattern along the water The flat direction is extended on the light incident surface. The diffuser panel of claim 25, wherein the centerline average roughness perpendicular to the horizontal direction ranges between 0.5 micrometers and 0.6 micrometers. A backlight module includes: a substrate; a plurality of light emitting diodes, a matrix is arranged on the substrate, and a spacing between the adjacent light emitting diodes is W ₁ ; as in claims 15 to 26 a diffusing plate corresponding to the light emitting diodes, and the distance between the diffusing plate and the light emitting diodes is D ₁ , and 1.25<W ₁ /D ₁ <1.5; and optical The diaphragm group corresponds to the diffuser plate configuration. The backlight module of claim 27, further comprising a reflective sheet disposed on the substrate. A display device, comprising: a backlight module according to any one of claims 27 or 28; and a display panel corresponding to the backlight module configuration.