TWI609215B - Backlight module - Google Patents

Description

Backlight module

The present invention relates to a surface light source device, and more particularly to a backlight module that can be used in a display device.

The backlight module can be divided into a direct type backlight module and a side-in type backlight module according to the light input mode, wherein the side-in type backlight module is mainly assembled by components such as a light source, a reflection sheet and a light guide plate. In the prior art, the quality of the planar light provided by the backlight module is often improved by the microstructure, for example, the Republic of China Patent Publication No. M400593, the Chinese Patent Publication No. 10316278A, the US Patent Publication No. 6425673, and the US Patent Publication No. 20100033989 .

FIG. 1 is a schematic diagram of a conventional backlight module and beam transfer. Referring to FIG. 1 , the backlight module 100 includes a light guide plate 110 , a light source 120 disposed beside the light incident surface 111 of the light guide plate 110 , and a reflective sheet 130 disposed under the light guide plate 110 . The light guide plate 110 has a lower surface 113 . The lower surface 113 is further provided with a microstructure 140. The microstructure 140 is used to change the reflection angle of the light beam 122 entering the light guide plate 110 from the light incident surface 111, so that the light beam 122 is emitted from the light exit surface 115 of the light guide plate 110. The reflective sheet 130 is used to reflect the light beam 122 leaking from the lower surface 113 of the light guide plate 110 back into the light guide plate 110, thereby increasing the efficiency of use of light.

However, in the conventional backlight module 100, the reflective sheet 130 and the light guide plate 110 are generally in close contact, but the surface of the light guide plate 110 may be dust or process. When a defect occurs on the surface of the light guide plate 110, a light beam (for example, the light beam 122a) reflected by the reflection sheet 130 after passing through the defect point and the light beam (for example, the light beam 122b) that is originally only reflected by the defect point on the light guide plate 110 The light-emitting surface 115 is partially overlapped (as shown in FIG. 2), so that the overlapping light beams 122a, 122b are too bright, resulting in a clear light-dark ridge of the planar light provided by the conventional backlight module 100. Therefore, it is highly desirable to propose a method for improving the apparent bright and dark ridges to provide good quality planar light.

The invention provides a backlight module, which can achieve the effect of lightening the flaw of the planar light provided by the backlight module.

Other objects and advantages of the present invention will become apparent from the technical features disclosed herein.

The backlight module provided in one embodiment of the present invention includes a light guide plate, a light source, and a reflective sheet. The light guide plate has a light incident surface and a bottom surface connected to the light incident surface. The light source is disposed beside the light incident surface of the light guide plate. The reflective sheet is disposed under the bottom surface of the light guide plate and has a reflective surface facing the bottom surface of the light guide plate. The reflective surface is provided with a plurality of dot-like microstructures to maintain a spacing between the reflective sheet and the light guide plate. The height is between 3 and 500 microns.

In an embodiment of the invention, the height of the dot microstructures is between 5 and 100 microns.

In an embodiment of the invention, each of the dot-like microstructures has a connecting surface connected to the reflecting surface, and the connecting surface has a width of 5 to 1000 micrometers.

In an embodiment of the invention, the width of the connecting surface is At 5 to 100 microns.

In an embodiment of the invention, the dot-like microstructures have a fullness on the reflective surface of between 20% and 80%.

In an embodiment of the invention, the dot-like microstructures have a fullness on the reflective surface of between 30% and 65%.

In an embodiment of the invention, the surface of each of the dot-like microstructures facing the bottom surface of the light guide plate is a smooth curved surface.

In an embodiment of the invention, each of the dot-like microstructures has a columnar shape and has a plane facing the bottom surface of the light guide plate and a side surface connected to the plane, and the joint between the plane and the side surface is curved.

In an embodiment of the invention, each of the dot-shaped microstructures has a connecting surface connected to the reflecting surface, and the joint between the connecting surface and the side surface is curved.

In an embodiment of the invention, the dot-like microstructures are arranged in a regular or irregular arrangement.

In an embodiment of the invention, the distribution density of the dot-like microstructures increases from a side close to the light incident surface toward a side farther from the light incident surface.

In an embodiment of the invention, the dot microstructures are uniformly distributed on the reflective surface.

In an embodiment of the invention, the bottom surface of the light guide plate is provided with a plurality of optical microstructures, and a portion of the optical microstructures contacts a portion of the dot microstructure.

Based on the above, the backlight module of the embodiment of the present invention has at least one of the following advantages: the reflective surface of the reflective sheet of the backlight module is provided with a bit-shaped microstructure to increase the spacing between the light guide plate and the reflective sheet, so that the guide is passed through The light beam reflected by the light-reflecting sheet and the light beam reflected by the reflective sheet can be generated to a large offset when transmitted to the light-emitting surface of the light guide plate, so as to reduce the overlapping area of the light beam directly reflected by the defect point on the light-emitting surface of the light guide plate. Further reducing the appearance of bright and dark lines For example, to achieve the effect of lightening the flat light provided by the backlight module.

The above and other objects, features and advantages of the present invention will become more <RTIgt;

100‧‧‧Study backlight module

110‧‧‧Light guide plate

111‧‧‧Into the glossy surface

113‧‧‧ bottom

115‧‧‧Glossy

120‧‧‧Light source

122, 122a, 122b‧‧‧ beams

130‧‧‧reflector

140‧‧‧Microstructure

200‧‧‧Backlight module

210‧‧‧Light guide plate

211‧‧‧Into the glossy surface

213‧‧‧ bottom

215‧‧‧Glossy

220‧‧‧Light source

222, 222a, 222b‧‧‧ beams

230‧‧‧reflector

231, 531‧‧ ‧ reflective surface

240‧‧‧Optical microstructure

250, 350, 450‧‧‧ point microstructure

251‧‧‧ surface

253, 353, 453‧‧ ‧ joints

260‧‧‧Optical film

351, 451‧‧ plane

354, 454, 456‧‧‧ joints

355, 455‧‧‧ side

G‧‧‧ spacing

FIG. 1 is a schematic diagram of a conventional backlight module and beam transfer.

2 is a schematic view showing a partial overlap of a light beam of a conventional backlight module on a light exit surface of a light guide plate.

3 is a schematic diagram of a backlight module and beam transfer according to an embodiment of the invention.

4 is a schematic view showing a partial overlap of a light beam of a backlight module on a light-emitting surface of a light guide plate according to an embodiment of the invention.

FIG. 5A is a schematic view showing a dot-like microstructure of a reflection sheet of a backlight module according to another embodiment of the present invention.

FIG. 5B is a schematic view showing the dot-like microstructure of a reflection sheet of a backlight module according to another embodiment of the present invention.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only directions referring to the additional drawings. Therefore, the directional terminology used is for the purpose of illustration and not limitation.

3 is a backlight module and a light beam transmission indicator according to an embodiment of the invention. intention. Referring to FIG. 3 , the backlight module 200 of the embodiment includes a light guide plate 210 , a light source 220 , and a reflective sheet 230 . The light guide plate 210 has a light incident surface 211 and a bottom surface 213 connected to the light incident surface 211. The light source 220 is disposed beside the light incident surface 211 of the light guide plate 210. The reflection sheet 230 is disposed below the bottom surface 213 of the light guide plate 210 and has a reflection surface 231 facing the bottom surface 213 of the light guide plate 210. The reflective surface 231 is provided with a plurality of dot-like microstructures 250 to maintain the spacing G between the reflective sheet 230 and the light guide plate 210. Further, the pitch G is, for example, a pitch between the reflection surface 231 of the reflection sheet 230 and the bottom surface 213 of the light guide plate 210.

In this embodiment, the light source 220 is used to provide the light beam 222, and the light beam 222 enters the light guide plate 210 via the light incident surface 211 of the light guide plate 210. Light source 220 can be a light emitting diode or other type of light emitting element. In addition, the bottom surface 213 of the light guide plate 210 is provided with a plurality of optical microstructures 240, for example, and a portion of the optical microstructures 240 contacts a portion of the dot microstructures 250. In addition, the spot microstructures 250 that are not in contact with the optical microstructures 240 are likely to contact a portion of the bottom surface 213 (not shown). The optical microstructure 240 is used to deflect the light beam 222 entering the light guide plate 210 from the light incident surface 211, so that the light beam 222 can be emitted from the light exit surface 215 of the light guide plate 210. In addition, the backlight module 200 may further include one or more optical films 260, such as a diffusion film, a brightness enhancement film, and the like. The optical film 260 is disposed above the light-emitting surface 215 of the light guide plate 210 to optimize planar light emitted from the light-emitting surface 215 of the light guide plate 210.

The light guide plate 210 is liable to form defects due to dust adhesion or defects of the optical microstructure 240. In the backlight module 200 of the embodiment, a dot-like microstructure 250 is disposed on the reflective sheet 230 to increase the gap between the light guide plate 210 and the reflective sheet 230. Spacing G. As such, a light beam (eg, the light beam 222a) that passes through the defect and is reflected by the reflective sheet 230 is transmitted to the light exit surface 215 of the light guide plate 210 to generate a large offset to reduce the defect on the light guide plate 210. Directly reflected beam (for example, the light beam 222b) overlaps the light-emitting surface 215, thereby reducing the phenomenon of bright and dark lines. As shown in FIG. 4, in comparison with the conventional backlight module 100, in the embodiment of the present invention, the light beam 222a and the light beam 222b are significantly less overlapped after being emitted from the light exit surface 215 of the light guide plate 210, and the light guide plate 210 may be further added. The distance G between the reflection sheet 230 and the light beam 222a and the light beam 222b are not overlapped (not shown in Fig. 3). Therefore, the backlight module 200 of the embodiment can effectively reduce the planar pupil caused by the defect, thereby improving the quality of the planar light.

In order to achieve the above-mentioned effects of the dot-shaped microstructures 250, in the present embodiment, the height of the dot-like microstructures 250 is, for example, between 3 and 500 microns, wherein the light beam 222a reflected by the reflection sheet 230 in order to avoid passing through the defects The offset is too large to easily overlap with the light beam 215 directly reflected by other defects (not shown) on the light exit surface 215 of the light guide plate 210. The height of the dot microstructure 250 is preferably between 5 and 100 micrometers. In addition, the height of the dot-like microstructures 250 is too low, as is the case with conventional reflective sheets that are not provided with the dot-like microstructures 250, so that most of the light beams 222 cannot be diffused through the dotted microstructures 250 disposed on the reflective sheets 230, and cannot be alleviated. The phenomenon of bright and dark lines cannot achieve the effect of lightening the flat light provided by the backlight module. If the height of the dot-shaped microstructures 250 is too high, the thickness of the entire backlight module 200 will increase, and the need for thinning and thinning cannot be achieved.

In the present embodiment, the dot microstructure 250 has a connection surface 253 connected to the reflection surface 231. The width of the connection surface 253 is, for example, 5 to 1000 μm, preferably 5 to 100 μm. Further, the width of the connection surface 253 is too small, like a conventional reflection sheet in which the dot-shaped microstructures 250 are not disposed, so that most of the light beams 222 cannot be diffused through the dot-like microstructures 250 disposed on the reflection sheet 230, and cannot be alleviated. The phenomenon of bright and dark lines cannot achieve the effect of lightening the flat light provided by the backlight module. The width of the connecting surface 253 is too large to reduce the phenomenon of bright and dark lines and to achieve the lightening of the planar light provided by the backlight module. Effect. In addition, the width of the connecting surface 253 referred to in the present invention is not limited to the specific shape of the dot-shaped microstructures 250. In particular, the attachment surface 253 may be, for example, rectangular, circular, elliptical, polygonal, or other shape. When the connecting surface 253 is circular, the width of the connecting surface 253 described above indicates the diameter of the connecting surface 253. In addition, in order to avoid other defects of planar light caused by the arrangement of the dot-like microstructures 250, the surface 251 of the point-like microstructures 250 of the present embodiment facing the bottom surface 213 of the light guide plate 210 is, for example, a smooth curved surface, and the dot-shaped microstructures 250 The connecting surface 253 is, for example, circular. Specifically, the dot-like microstructures 250 of the present embodiment are, for example, semi-spherical. However, the specific shape of the dot-like microstructure of the present invention is not limited to the above. In another embodiment, as shown in FIG. 5A, the dot-shaped microstructure 350 is, for example, columnar and has a surface facing the light guide plate 210. The plane 351 of the bottom surface 213 and the side surface 355 connected to the plane 351, and the joint 354 of the plane 351 and the side surface 355 are, for example, curved, and the area of the plane 351 is substantially equal to the area of the joint surface 353. In another embodiment, as shown in FIG. 5B, the dot microstructure 450 has a connection surface 453 connected to the reflection surface 531. The junction 454 of the plane 451 and the side surface 455 is, for example, curved, and the side surface 455 is close to the reflection surface 531. The joint 456 is also arcuate, and the area of the plane 451 is smaller than the area of the joint surface 453.

In addition, depending on the needs of use, the process of the dot microstructure 250 may include, but is not limited to, a printing process, an inkjet process, an ultraviolet forming process, or other processes. The dot microstructure 250 has, for example, a certain aspect ratio, and the aspect ratio herein is the ratio of the height of the dot microstructure 250 to the width of the connection surface 253. The aspect ratio of the point-like microstructures 250 of the present embodiment is preferably between 0.15 and 0.25, but not limited thereto, in combination with the limitation of the height of the point-like microstructures 250 and the width of the connection surface 253.

The dot-like microstructure 250 of the embodiment has a fullness ratio of the reflective surface 231 of, for example, between 20% and 80%, wherein the fullness of the dot-shaped microstructure 250 is The percentage of the area occupied by the reflecting surface 231 and the entire area of the reflecting surface 231. If the fullness is too small, most of the light beam 222 cannot be diffused through the dot-shaped microstructures 250 disposed on the reflective sheet 230, and the phenomenon of bright and dark lines cannot be alleviated, and the effect of lightening the planar light provided by the backlight module cannot be achieved. Too large a fullness will cause the dot microstructures 250 to be connected to each other to destroy the shape and function of the dot microstructures 250, and instead form another flaw. Preferably, the dot microstructure 250 has a fullness of the reflective surface 231 of between 30% and 65%. In addition, the dot-like microstructures 250 may be arranged, for example, in a regular or irregular arrangement. The distribution density of the dot microstructures 250 on the reflective surface 231 can be evenly distributed, that is, the dot microstructures 250 are evenly distributed on the reflective surface 231, or can be adjusted according to different design requirements, for example, from the side close to the light incident surface 211 toward the far side. One side of the smooth surface 211 is gradually increased. In addition, the heights of the dot microstructures 250 distributed on the reflecting surface 231 may be equal or unequal, and the widths of the connecting surfaces 253 may be equal or unequal, which is not limited by the present invention.

In summary, the backlight module of the embodiment of the present invention has at least one of the following advantages: the reflective surface of the reflective sheet of the backlight module is provided with a bit-shaped microstructure to increase the spacing between the light guide plate and the reflective sheet, so as to A light beam that passes through the defect of the light guide plate and is reflected by the reflection sheet can generate a large offset when transmitted to the light exit surface of the light guide plate to reduce the overlap of the light beam directly reflected through the defect point on the light exit surface of the light guide plate. The area, in turn, reduces the phenomenon of bright and dark lines, so as to achieve the effect of lightening the flat light provided by the backlight module. Therefore, the backlight module of the present invention can provide planar light of better quality.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the summary section And the headings are only used to assist in the search for patent documents and are not intended to limit the scope of the invention. In addition, the terms "first", "second" and the like mentioned in the specification or the scope of the claims are only used to name the elements or distinguish different embodiments or ranges, and are not intended to limit the number of elements. Upper or lower limit.

200‧‧‧Backlight module

210‧‧‧Light guide plate

211‧‧‧Into the glossy surface

213‧‧‧ bottom

215‧‧‧Glossy

220‧‧‧Light source

222, 222a, 222b‧‧‧ beams

230‧‧‧reflector

231‧‧‧reflecting surface

240‧‧‧Optical microstructure

250‧‧‧ point microstructure

251‧‧‧ surface

253‧‧‧ Connection surface

260‧‧‧Optical film

G‧‧‧ spacing

Claims (11)

A backlight module includes: a light guide plate having a light incident surface and a bottom surface connected to the light incident surface; a light source disposed beside the light incident surface of the light guide plate; and a reflective sheet disposed thereon a bottom surface of the light guide plate having a reflective surface facing the bottom surface of the light guide plate, the reflective surface being provided with a plurality of dot-like microstructures for maintaining a spacing between the reflective sheet and the light guide plate. The height of the point-like microstructure is between 3 and 500 microns, and the dot-like microstructures have a fullness of between 30% and 65% on the reflecting surface. The backlight module of claim 1, wherein the dot-like microstructures have a height of 5 to 100 micrometers. The backlight module of claim 1, wherein each of the dot-shaped microstructures has a connecting surface connected to the reflecting surface, the connecting surface having a width of 5 to 1000 μm. The backlight module of claim 3, wherein the connecting surface has a width of 5 to 100 micrometers. The backlight module of claim 1, wherein a surface of each of the point-like microstructures facing the bottom surface of the light guide plate is a smooth curved surface. The backlight module of claim 1, wherein each of the dot-shaped microstructures has a columnar shape and has a plane facing the bottom surface of the light guide plate and a side surface connected to the plane, and the plane is The connection at the side is curved. The backlight module of claim 6, wherein each of the dot-shaped microstructures has A connecting surface connected to the reflecting surface, and the connecting portion of the side close to the reflecting surface is curved. The backlight module of claim 1, wherein the dot-like microstructures are arranged regularly or irregularly. The backlight module of claim 1, wherein the distribution density of the dot-like microstructures increases from a side close to the light incident surface toward a side away from the light incident surface. The backlight module of claim 1, wherein the dot-like microstructures are evenly distributed on the reflective surface. The backlight module of claim 1, wherein the bottom surface of the light guide plate is provided with a plurality of optical microstructures, and a portion of the optical microstructures contact portions of the dot microstructures.