TWI547741B - Thin type backlight module - Google Patents

Description

Thin backlight module

The present invention relates to a backlight module; in particular, the present invention relates to a thin backlight module.

In recent years, the technology of liquid crystal display devices has gradually matured. As consumer preferences and demands increase, liquid crystal display devices are becoming thinner. In order to achieve the purpose of thinning, various components of the liquid crystal display device are required to be reduced in thickness, such as a display panel, an optical film, and a backlight module. In the backlight module, since the required light mixing space is required, the required thickness is usually large, and thus it is also the main target for thickness reduction.

FIG. 1 shows a conventional direct type backlight module. As shown in FIG. 1, the backlight module 1 includes a light box 9, a light source 8, and a hole 3. The hole piece 3 substantially divides the light box 9 into a lower layer space S1 and an upper layer space S2, wherein the light source 8 is disposed in the lower layer space S1 in the light box 9, and light generated by the light source 8 is incident on the upper layer space S2 via the hole sheet 3. Further, the light emitted from the hole 3 enters the upper space S2 and is mixed. Further, the diffusion plate 2 and the hole piece 3 are opposed to each other by the upper layer space S2, and the uniformity of light emission is improved.

When the backlight module 1 shown in FIG. 1 is thinned, the height of the light box 9 needs to be reduced, that is, the height of the lower space S1 and/or the upper space S2 is reduced. However, when the height H2 is reduced, the light mixing space provided by the upper space S2 becomes small. Since the projection range of the light source 8 on the hole 3 and the vicinity thereof are generally small or not, and the light extraction rate is small, the upper space is required. S2 provides sufficient light mixing space to have the same or similar brightness as other regions. When the light mixing space is reduced and the light mixing is incomplete, it is easy for the backlight module 1 to cause a dark spot corresponding to the portion of the light source 8, which affects the optical taste.

The object of the present invention is to provide a backlight module, which can be reduced The thickness of the back light module.

Another object of the present invention is to provide a backlight module that solves problems such as occurrence of dark spots.

Another object of the present invention is to provide a backlight module that provides better optical taste.

The backlight module of the present invention comprises a light source module and an optical control film. The light source module includes at least one light source. The optical control film is disposed above the light source module and has a plurality of light exit holes, wherein the light generated by the optical control film distribution light source is emitted through the light exit holes at different positions. The optical control film comprises at least one block corresponding to at least one light source, and each of the blocks has a basin portion surrounded by the light exit holes distributed in the block. The basin is recessed relative to other locations in the block and is closer to the plane of the light source. The projection range of the light source corresponding to the block on the block at least partially overlaps the distribution range of the basin.

〔this invention〕

10‧‧‧Backlight module

100‧‧‧Light source module

150, 150a‧‧‧ light source

160‧‧‧ cabinet

161‧‧‧floor

162‧‧‧Side wall

200‧‧‧Optical Control Film

220‧‧‧Lighting hole

250‧‧‧ basin

300‧‧‧Diffuser

400‧‧‧reflector

B‧‧‧ Block

B0‧‧‧ non-porous area

D1, D1’, D2‧‧‧ distance

P1‧‧‧lower space

P2‧‧‧Under space

R‧‧‧Projection range

[study]

1‧‧‧Backlight module

2‧‧‧Diffuser

3‧‧‧ holes

4‧‧‧reflector

5‧‧‧Optical diaphragm

8‧‧‧Light source

9‧‧‧Lightbox

S1‧‧‧Under space

S2‧‧‧Upper space

H2‧‧‧ Height

1 is a side view of a conventional backlight module; FIG. 2A is an exploded view of an embodiment of the backlight module of the present invention; and FIG. 2B is a light source module and an optical control film of the embodiment shown in FIG. 2A. Prone 3A-3B are schematic side views of the embodiment shown in FIG. 2A; FIGS. 4A-4B are schematic views showing other embodiments of the optical control film of the present invention; and FIGS. 5A to 5B are optical control films of the present invention. FIG. 6A to FIG. 6B are schematic views showing other embodiments of the optical control film of the present invention; and FIG. 7 is a schematic view showing another embodiment of the optical control film of the present invention.

The backlight module of the present invention, as shown in FIG. 2A, includes a light source module 100 and an optical control film 200. The light source module 100 includes at least one light source 150; the light source 150 is preferably arranged in the form of a matrix of rows and columns, as shown in FIG. 2A. The optical control film 200 is disposed above the light source module 100 and has a plurality of light exit holes 220. In the present embodiment, the light exit holes 220 are provided in the form of perforations; however, in different embodiments, the light exit holes 220 may also be recessed holes that do not penetrate. The light exit hole 220 occupies an area on the optical control film 300; the occupied area is referred to as an open area. Further, the opening area contributed by the light exit holes 220 on the optical control film 200 per unit area constitutes a unit opening ratio of the optical control film 200. The unit opening area ratio or the aperture ratio is preferably a standardized ratio value without a unit. Furthermore, the optical control film 200 has a reflection effect toward one surface of the light source 150. When the light generated by the light source 150 reaches the portion of the optical control film 200 where the light exit hole 220 is not provided, the light can be reflected (at least partially reflected) back to the light source module. After 100, the light is emitted at other positions, so that the light generated by the light source 150 can be distributed through the light exit holes 220 at different positions. In addition to having a plurality of light exit holes 220 for light to pass through, the optical control film 200 itself may have a light transmittance; for example, in an embodiment of the backlight module of the present invention, the optical control film has a light transmittance of 1%. , but not limited to this.

The optical control film 200 preferably includes at least one block B (as shown by the dashed line on the optical control film 200 in FIGS. 2A and 2B) respectively corresponding to at least one light source 150 in the light source module 100. Each block B has a plurality of light exit holes 220 and at least one basin portion 250, wherein the basin portion 250 is surrounded by a plurality of light exit holes 220 distributed in each block B. In the embodiment of the present invention, different positions of the same optical control film 200 have different unit opening area ratios; further, in each block B of the same optical control film 200, the ratio of unit opening areas of different parts is also different. . In the preferred embodiment, as shown in FIG. 2B, the unit opening area ratio of the light exit holes 220 in each block B is preferably increased in the outer side of the block B centering on the basin portion 250 in the block B. Specifically, the light exit hole 220 in the vicinity of the basin portion 250 may be smaller, thinner, or smaller and less sparse. The farther away from the basin portion 250, the light exit hole 220 may be relatively large, dense, or Big and dense. In detail, the basin 250 is recessed relative to other locations in the block B and closer to the plane of the light source 150; in other words, as the side of the optical control film 200 facing the light source 150, the protrusion formed by the basin 250 can be seen. In addition, the basin 250 preferably has no light exit holes 220; the light source 150 has no light exit holes 220 within the projection range on the optical control film 200, or has a relatively low unit aperture ratio. In addition, the projection range R of the light source 150 corresponding to each block B on the block B preferably overlaps at least partially with the distribution range of the basin 250, as illustrated in FIGS. 2B and 3A.

Therefore, the tub portion 250 of the optical control film 200 is closer to the light source 150 than the other portions. Furthermore, the optical control film 200 itself has a light transmittance, and since the bottom of the tub portion 250 is closer to the light source 150 in the vertical direction, the light throughput of the tub portion 250 will be increased to reduce the upper portion of the tub portion 250. The opportunity to create dark spots.

In the embodiment of the preferred backlight module 10, the diffusion plate 300 is further disposed on the side of the optical control film 200 opposite to the light source module 100. As shown in FIG. 3A, the diffusion plate 300 is more Preferably, the optical control film 200 is spaced apart from each other by, for example, a distance D2; and the basin 250 on the optical control film 200 can further partially open the distance between the optical control film 200 and the diffusion plate 300, for example, the diffusion plate 300 and the optical control The distance of the membrane 200 is D2', where D2' is greater than D2. In summary, the average vertical distance between the face of the basin 250 facing the diffuser plate 300 and the diffuser plate 300 is greater than the average vertical distance between the other locations in the block B on the same face and the diffuser plate 300, so the basin 250 and its vicinity The light enjoys more mixed light space. In addition, the light source module of the present invention may further comprise a reflective sheet 400 disposed relative to the optical conditioning film 200.

The backlight module of the present invention may further comprise a carrier board, a back board or a box body; wherein the carrier board or the back board may be formed with a side wall at a periphery thereof to form a receiving space of the carrier board or the back board. The carrier board, the back board or the box body can be used to carry the light source 150, and can carry or accommodate the optical control film 200 and the diffusion board 300. In one embodiment, the reflective sheet 400 of the light source module is also disposed on/in the carrier, the back sheet or the case, opposite to the optical control film 200. As shown in FIGS. 3A-3B, the housing 160 carries the light source 150 and the reflective sheet 400, and houses the optical control film 200 and the diffusion plate 300. The optical control film 200 preferably is separated from the light source 150 by a distance D1. In addition, the reflective sheet 400 is at least partially at the same plane or the same level as the light source 150; in other words, the partial reflective sheet 400 has a direction in which the portion of the reflective sheet 400 is substantially the same as the plane of the light source 150, or Parallel and close to each other. The light exiting from the light source 150 reaches the optical control film 200 through the interlayer space formed by the distance D1. The light-emitting holes 220 on the optical control film 200 distribute light and illuminate the light. The light is distributed by the optical control film 200 and the light exit hole 220, and the light is transmitted through, which attenuates the unevenness of the amount of light generated by the distance from the light source 150; further, the dimming of the optical control film 200 The effect can be adjusted by factors such as the degree of separation of the position of the optical control film 200 and its basin 250 from the light source 150 (distance D1).

Furthermore, as in the embodiment of the backlight module 10, the optical control film 200 having the distance D1 from the light source 150 preferably forms a lower space P1 with the casing 160 and is disposed in the casing 160 with the diffusion plate 300 spaced apart from each other by a distance D2. The circumference constitutes the upper space P2; wherein the lengths of the distances D1 and D2 preferably reflect the heights of the lower space P1 and the upper space P2, respectively. The heights of the lower space P1 and the upper space P2 are changeable. In the embodiment of the present invention, when the height of the upper layer space P2 is reduced, since the basin portion 250 on the optical control film 200 partially opens the distance between the optical control film 200 and the diffusion plate 300, the basin portion 250 and its vicinity emit light. Therefore, it enjoys more mixed light space. Therefore, by the arrangement of the tub portion 250, the light-emitting quality of the backlight module 10 of the present invention can be maintained while reducing the upper layer space P2. In an embodiment of the invention, the height of the lower space P1 of the backlight module 10 is approximately 7.5 mm, the height of the upper space P2 is approximately 5 mm, and the depth of the basin 250 (toward the plane of the light source 150) It is 2 mm. The depth of the basin 250 can be designed according to the light source 150 of the backlight module 10 and the distance D1.

On the other hand, the casing 160 includes a bottom plate 161 and a side wall 162, wherein the casing 160 surrounding the lower space P1 is a bottom plate 161 and a lower side wall 162. The light source 150 may be disposed on the bottom plate 161; the reflective sheet 400 may be disposed in the lower layer space P1 along the inner surface of the bottom plate 161 and the inner surface of the lower side wall 162. Further, a reflection space surrounded by the reflection sheet 400 is disposed in the lower layer space P1. Thereby, when the light that is not emitted by the light exit hole 220 is reflected from the optical control film 200, the light can be further emitted toward the optical control film 200 via the reflective sheet 400 and/or the reflective space, thereby improving light utilization efficiency, and distributing the light source 150. The light exits through the light holes 220 at different positions. In addition, in other embodiments, a reflective material may also be applied to the portion of the casing 160 around the lower space P1 to form a reflective space. Further, the optical control film 200 may have a reflection effect toward one surface of the light source 150, and constitute a reflection space with the reflection sheet 400 or the case 160 (coated with a reflective material) around the lower layer space P1.

As described above, the projection range R of the light source 150 corresponding to the block B on the block B at least partially overlaps the distribution range of the basin 250; preferably, the distribution range of the basin 250 is substantially located in the area. The light source 150 corresponding to the block B is within the primary light illumination range. The light source 150a of FIG. 3B is taken as an example for illustration. For example, the light source 150a can reflect a light-emitting area of diameter d in a block B of the optical control film 200; the light-emitting area and the basin 250, wherein the basin 250 is circular and has a diameter d 'When the diameter d' is preferably less than or equal to d. Further, the block B includes the non-porous area B ₀ ; that is, the area where the light exit hole 220 is not provided. The plurality of light exit holes 220 are preferably distributed on the block B in a manner surrounding the non-porous area B ₀ ; in addition, the portion of the block B other than the non-porous area B ₀ is preferably uniformly distributed with the light exit holes 220, and only the light holes can be thinned out. It can be dense and the distance between holes can be far. The non-porous region B _{0 is} preferably a continuous and fully shaped region such as a circular or regular polygonal region. The basin 250 is located in the non-porous region B ₀ ; in addition, the basin 250 may range from large to small, and preferably between 70% and 80% of the area of the non-porous region B ₀ . In an embodiment of the invention, the area of the non-porous region B ₀ is approximately 10 square mm, and preferably, the area of approximately 7 to 8 square mm is the extent of the basin portion 250. The non-porous region B ₀ and its 70% to 80%-sized basin 250 are designed to reduce the direct light output of the optical control film 200 at the near-light source 150 (due to the distribution of the non-porous region B ₀ ), and then appropriate Compensating for the amount of light that is weak and sparse in the projection range R due to insufficient light mixing space.

As described above, the depth of the basin 250 can be designed according to the light source of the backlight module and the distance D1. Furthermore, the depth of the basin 250, the height of the distance D1 or the lower space P1, and the distance D2 (i.e., the height of the upper space P2) are preferably coordinated, wherein the deeper the basin 250, that is, the basin 250 is diffused toward the diffusion. When the side of the plate 300 is farther from the diffuser plate 300, the height of the upper space P2 can be made smaller because a rich mixed light space is provided. On the other hand, the longest vertical distance between the face of the basin 250 facing the diffuser plate 300 and the diffuser plate 300 is greater than the longest vertical distance between the face of the basin 250 facing the light source 150 and the light source 150, thereby increasing the light mixing space and the light output. Uniformity and avoid back A portion of the light module corresponding to the light source may create a dark spot.

In detail, the tub 250 may comprise a basin structure. As shown in FIG. 4A, the basin 250 is a basin-shaped structure; the basin-shaped structure may have, for example, a curved bottom 252, and is a circular arc surface facing one side of the light source 150, but is not limited thereto, for example, A continuous surface composed of arcs of different curvature radii. In other embodiments, the tub 250 can comprise two or more basin-like structures as shown in Figure 4B. The projection range R of the light source 150 corresponding to each block B on the block B preferably overlaps at least partially with the distribution range of the basin 250; the center of the projection range R is preferably the central portion of the basin structure. Altogether.

As shown in FIGS. 5A-5B, the basin 250 can also be a recessed structure of other types. As shown in FIG. 5A, the tub portion 250 is a rectangular recess; as shown in FIG. 5B, the tub portion 250 is a pyramid-shaped recess. In other embodiments, the crater 250 can comprise two or more basin-like structures as shown in Figures 6A-6B. The projection range R of the light source 150 corresponding to each block B on the block B preferably overlaps at least partially with the distribution range of the basin 250; the center of the projection range R is preferably the central portion of the basin structure. Altogether.

The basin portion 250 is formed in the structure of the optical control film 200, and the material thereof is preferably the same as the other portions of the optical control film 200; that is, the tub portion 250 and the other portions of the block B have continuous materials. Sex. On the other hand, the tub portion 250 can be formed integrally with the optical control film 200; alternatively, the tub portion 250 can be additionally processed on the optical control film. For example, it is obtained by embossing or the like in each block of the optical control film. The planning of the block B, the distribution range of the basin 250, the shape of the basin 250, and the depth of the basin 250 may be designed according to the light source of the backlight module and the distance D1, but are not limited thereto.

In an embodiment of the invention, the optical control film 200 is densely bonded to the pot portion 250. The degree may be lower than the material density of other parts in the block B. In other embodiments, as shown in FIG. 7, the thickness of the optical conditioning film 200 at the basin 250 may be thinner than the thickness of other portions of the block B. For example, when the basin 250 is formed, the thickness of the basin 250 is thinner or less dense than the other portions of the block B due to the extension of the optical control film of the portion to form the bottom portion 252. In addition, the light transmittance of the basin 250 may be slightly higher than that of other portions of the optical control film 200 that are not provided with the light exit hole 220, so that the primary light generated by the light source 150 is allowed to pass through, thereby reducing the space due to the light mixing. A dark spot situation caused by insufficient. The material density and/or thickness of the basin portion 250 may be designed according to the light source of the backlight module and the height of the distance D1 or the lower layer space P1, but is not limited thereto. With a lower material density and/or thickness, the basin 250 can again increase the throughput therethrough.

The present invention has been described by the above-described related embodiments, but the above embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the invention. On the contrary, modifications and equivalents of the spirit and scope of the invention are included in the scope of the invention.

10‧‧‧Backlight module

100‧‧‧Light source module

150‧‧‧Light source

160‧‧‧ cabinet

200‧‧‧Optical Control Film

220‧‧‧Lighting hole

250‧‧‧ basin

300‧‧‧Diffuser

B‧‧‧ Block

Claims (8)

A backlight module comprising: a light source module comprising at least one light source; and an optical control film disposed above the light source module and having a plurality of light exit holes; wherein the optical control film distributes the light generated by the light source to different The light-emitting aperture of the position passes through; the optical control film comprises at least one block corresponding to at least one light source, each of the blocks comprises a non-porous area, and a basin is located in the non-porous area The light exiting holes surround the basin and are distributed outside the non-porous region; wherein the basin is recessed relative to other locations in the block and is closer to the plane of the light source, the block Correspondingly, the projection range of the light source on the block at least partially overlaps the distribution range of the basin, and the distribution range of the basin is located within a primary light illumination range of the light source corresponding to the block. The backlight module of claim 1, wherein the basin is distributed between 70% and 80% of the non-porous area. The backlight module of claim 1, further comprising a diffusion plate disposed on a side of the optical control film opposite to the light source module; wherein the basin portion faces a surface of the diffusion plate and the diffusion plate The average vertical distance is greater than the average vertical distance between the other locations in the block on the same side and the diffuser. The backlight module of claim 3, wherein a longest vertical distance between the face of the basin toward the diffuser plate and the diffuser plate is greater than a longest vertical distance between the face of the basin and the light source and the light source. The backlight module of claim 1, wherein the tub portion has material continuity with other portions of the block. The backlight module of claim 1, wherein the material density of the basin is greater than other parts of the block The material density is low. The backlight module of claim 1, wherein the thickness of the basin is thinner than the thickness of other portions of the block. The backlight module of claim 1, wherein the light source module further comprises a reflective sheet, at least part of the plane of the reflective sheet being substantially the same as a plane of the at least one light source, and at least part of the reflective sheet is opposite to the optical control Membrane setting.