TWI499815B - Back-light module - Google Patents

Description

Backlight module

The present invention relates to an optical module, and more particularly to a backlight module.

The backlight module generally includes a light source and a light guide plate, and the light guide plate is configured to guide a scattering direction of the light generated by the light source, so as to convert the point light source or the line light source in the backlight module into a surface light source and provide the light source disposed above the backlight module. Display panels or billboards, etc.

At present, the backlight module on the market can be roughly divided into a high-luminance collimated mode backlight module and a wide viewing angle mode backlight module according to the light field shape of the light. 1A is a schematic diagram of a light field shape of a high-luminance collimated mode backlight module, and FIG. 1B is a schematic diagram of a light field shape of a wide viewing angle mode backlight module. Referring to FIG. 1A, the high-luminance collimated mode backlight module has a relatively concentrated light field shape, and can concentrate energy on a user, so that the luminous efficiency is higher than that of a general non-concentrated light field-shaped backlight module. . In addition, due to the concentration of energy, people nearby can not receive energy, so it has anti-peep effect, and is widely used in personalized products, such as mobile phones, electricity and so on. However, the advantage is also The disadvantage is that the panel using the high-intensity collimation mode backlight module can not allow people in different angle directions to simultaneously view the image.

Referring to FIG. 1B, the wide viewing angle mode backlight module has a relatively divergent light field shape, which enables people in different angle directions to receive energy, and thus is widely used in shared products such as televisions and advertising billboards. However, the disadvantage is that the energy is too dispersive, resulting in relatively high energy consumption. To maintain the average energy of each user, a high power source is needed to provide the desired brightness. In addition, the wide viewing angle mode backlight module cannot achieve the anti-peep function. Therefore, how to provide a dual mode (including high-luminance collimation mode and wide viewing angle mode) backlight module that switches modes according to the user's needs is a future trend.

The present invention provides a backlight module that is capable of providing a relatively concentrated and relatively divergent light field shape.

A backlight module of the present invention includes a light guiding module, a plurality of first light sources, and a plurality of second light sources. The light guiding module includes a first light guiding plate, a second light guiding plate, a plurality of first microstructures and a plurality of second microstructures. The first light guide plate has a first bottom surface and a first top surface. The first microstructure is located on the first bottom surface and protrudes outward from the first bottom surface. The second light guide plate has a second bottom surface, a second top surface, and a connection surface connecting the second bottom surface and the second top surface, and the second bottom surface is located between the first top surface and the second top surface. The second microstructure is located on the second top surface and protrudes outward from the second top surface. The second light guide plate includes a plurality of light collecting portions. Each concentrating portion has a light incident surface and a light exit surface, and the light exit surface is connected and connected The width of the illuminating surface is greater than the width of the illuminating surface. The first light source is located beside the light incident surface. The second light source is located next to the connection surface.

Based on the above, the backlight module of the present invention concentrates the light beam from the first light source by using the concentrating portion to provide a relatively concentrated light field shape, thereby achieving the concentrating effect of the high-luminance collimating mode backlight module. In addition, by placing the second light source beside the connection surface, the light beam from the second light source is directly incident into the second light guide plate to provide a relatively divergent light field shape, thereby achieving a wide-angle effect of the wide viewing angle mode backlight module. . In addition, the backlight module of the present invention can better control the angle of the light beam emitted by the second top surface or the second microstructure through the arrangement of the first light guide plate and the second light guide plate, thereby improving the backlight module. Luminous efficiency.

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

100, 200, 300‧‧‧ backlight module

110, 110a‧‧‧Light guide module

120‧‧‧First light source

130‧‧‧second light source

112‧‧‧First light guide

114‧‧‧Second light guide

116‧‧‧ Third light guide

B1‧‧‧ first bottom surface

B2‧‧‧ second bottom surface

C‧‧‧ connection surface

D, d‧‧‧ distance

D1‧‧‧ first direction

D2‧‧‧ second direction

H‧‧‧镂空部

L‧‧‧beam

LCP‧‧‧The Department of Concentration

M1‧‧‧ first microstructure

M2, M2a‧‧‧ second microstructure

P1, P2‧‧‧ intercept

S‧‧‧ surface

S1‧‧‧ into the glossy surface

S2‧‧‧ shiny surface

T1‧‧‧ first top

T2‧‧‧ second top surface

W1, W2‧‧‧ width

Θ1‧‧‧first bottom angle

Θ2‧‧‧second base angle

A-A’‧‧‧ segment

FIG. 1A is a schematic diagram of a light field shape of a high-luminance collimated mode backlight module.

FIG. 1B is a schematic diagram of a light field shape of a wide viewing angle mode backlight module.

2A is a schematic diagram of a backlight module in accordance with a first embodiment of the present invention.

Figure 2B is a side elevational view of Figure 2A.

3A and 3B are partial top views of Fig. 2A.

4A and 4B are respectively a light field shape distribution diagram of Figs. 3A and 3B.

5A to 5C are various embodiments of the connection face corresponding to the second light source.

6 is a schematic diagram of a backlight module in accordance with a second embodiment of the present invention.

FIG. 7 is a schematic diagram of a backlight module in accordance with a third embodiment of the present invention.

2A is a schematic diagram of a backlight module in accordance with a first embodiment of the present invention. Figure 2B is a side elevational view of Figure 2A. Referring to FIG. 2A and FIG. 2B , the backlight module 100 of the embodiment includes a light guiding module 110 , a plurality of first light sources 120 , and a plurality of second light sources 130 .

The light guiding module 110 includes a first light guiding plate 112, a second light guiding plate 114, a plurality of first microstructures M1, and a plurality of second microstructures M2. The first light guide plate 112 has a first bottom surface B1 and a first top surface T1 opposite to the first bottom surface B1. The first microstructure M1 is located on the first bottom surface B1 and protrudes outward from the first bottom surface B1. In the embodiment, the first light guide plate 112 and the first microstructure M1 are, for example, but not limited to, integrally formed.

The first microstructures M1 of the present embodiment extend, for example, respectively in the first direction D1 and in the second direction D2, wherein the second direction D2 is, for example, perpendicular to the first direction D1. In the present embodiment, each of the first microstructures M1 is, for example, a corner cylinder. That is, each of the first microstructures M1 has a base angle of 90 degrees and a first base angle of less than 90 degrees. Furthermore, the first microstructures M1 are the same size and have a continuous distribution. For example, the intercept P1 of each first microstructure M1 is, for example, 50 microns.

The second light guide plate 114 is located on the first light guide plate 112, and the second light guide plate 114 has a second bottom surface B2, a second top surface T2, and a second bottom surface B2 and a second connection. The connecting surface C of the top surface T2, wherein the second bottom surface B2 is located between the first top surface T1 and the second top surface T2. The second microstructure M2 is located on the second top surface T2 and protrudes outward from the second top surface T2. In this embodiment, the second light guide plate 114 and the second microstructure M2 are, for example, but not limited to, integrally formed.

The second microstructure M2 of the present embodiment is disposed, for example, in parallel with the first microstructure M1. Specifically, the second microstructures M2 respectively extend along the first direction D1 and are arranged along the second direction D2. In this embodiment, each of the second microstructures M2 is also, for example, a corner cylinder. That is, each of the second microstructures M2 has a base angle of 90 degrees and a second base angle of less than 90 degrees. In addition, the second microstructure M2 is the same size. For example, the intercept P2 of each second microstructure M2 is, for example, 50 microns. Furthermore, the distribution density of the second microstructure M2 on the second top surface T2 increases, for example, as the distance from the connection surface C increases.

In addition, the second light guide plate 114 includes a plurality of light collecting portions LCP. Each of the light collecting portions LCP has a light incident surface S1 and a light exit surface S2 that connects the connection surfaces C. In the present embodiment, the width W1 of the light incident surface S1 is designed to be smaller than the width W2 of the light exit surface S2 to enhance the effect of the light collecting portion LCP collecting the light beam.

The first light source 120 is located beside the light incident surface S1. The second light source 130 is located beside the connection surface C. These first light sources 120 and these second light sources 130 are, for example, a plurality of light emitting diodes or other suitable light sources. Further, the first light source 120 and the second light source 130 are arranged, for example, in the first direction D1. In the present embodiment, the first light source 120 and the second light source 130 are, for example, alternately arranged in the first direction D1. In detail, the second light source 130 is located, for example, on both sides of the concentrating portion LCP and faces the connection surface C. However, the arrangement of the first light source 120 and the second light source 130 of the present invention is not limited to the above. It is described that those skilled in the art can change the arrangement of the first light source 120 and the second light source 130 according to their design requirements.

In this embodiment, the backlight module 100 may further include a third light guide plate 116 between the first light guide plate 112 and the second light guide plate 114, wherein the refractive indexes of the first light guide plate 112 and the second light guide plate 114 It is larger than the refractive index of the third light guide plate 116. In addition, the refractive indices of the first light guide plate 112 and the second light guide plate 114 may be the same or different. For example, the material of the first light guide plate 112 and the second light guide plate 114 is, for example, polymethylmethacrylate (PMMA), and the refractive index thereof is, for example, 1.49, and the material of the third light guide plate 116 is, for example, iron fluoride. Teflon has a refractive index of, for example, 1.35.

When the first light source 120 or the second light source 130 emits the light beam L, if the incident angle of the light beam L incident on the second top surface T2 and the second bottom surface B2 exceeds a critical angle, the light beam L is transmitted to the second in a total reflection manner. Inside the light guide plate 114. However, when the light beam L is transmitted to the second microstructure M2, the reflection angle of the light beam L is changed, thereby changing the incident angle at which the light beam L is incident to the second bottom surface B2. When the incident angle of the light beam L incident on the second bottom surface B2 is smaller than the critical angle, the light beam L is refracted into the third light guide plate 116 and transmitted to the first light guide plate 112. The light beam L transmitted into the first light guide plate 112 is transmitted to the first microstructure M1 to change its reflection angle again, thereby changing the incident angle thereof incident on the first top surface T1. By making the incident angle of the light beam L incident on the first top surface T1 smaller than the critical angle, the light beam L can pass through the third light guide plate 116 again and be transmitted to the second light guide plate 114, and can be emitted from the second light guide plate 114. In this embodiment, the surface of the first microstructure M1 not connected to the first bottom surface B1 may be a reflective surface, for example, the first micro The surface S of the structure M1 not connected to the first bottom surface B1 forms a highly reflective substance to preferably transmit the light beam L upward.

Through the angular design of the first microstructure M1 and the second microstructure M2, and by changing the arrangement position of the first microstructure M1 on the first top surface T1, the traveling direction of the light beam L can be controlled, thereby enabling better control. The angle of the light beam L emitted by the second top surface T2 or the second microstructure M2 is, for example, such that the light beam L is emitted at a small angle. For example, in the first microstructures M1 of the embodiment, the first base angle θ1 falls within a range of 50 degrees to 70 degrees, for example, and the second apex angle θ2 of each second microstructure M2 is, for example, a drop. In the range of 1 degree to 10 degrees. In addition, a 90 degree bottom angle of each of the first microstructures M1 is closer to the connection surface C than the first base angle θ1, and a 90 degree bottom angle of each of the second microstructures M2 is closer to the connection surface C than the second apex angle θ2 .

In the prior art, the backlight module is usually only provided with a light guide plate, and the bottom of the light guide plate is provided with a microstructure to destroy the total reflection phenomenon by means of scattering, so that the light beam is emitted from the light exit surface. However, in addition to the difficulty in controlling the angle at which the light beam is emitted from the light guide plate, most of the light beams are emitted from the light guide plate at a large angle, thereby reducing the overall luminous efficiency of the backlight module. In contrast, the present embodiment utilizes the arrangement of two or more light guide plates, and the light beam emitted from the second top surface T2 or the second microstructure M2 can be effectively controlled by the design of the refractive index and the apex angle of the light guide plate. The angle of L increases the luminous efficiency of the backlight module 100.

In addition, by appropriately modulating the thicknesses of the first light guide plate 112, the second light guide plate 114, and the third light guide plate 116, the electronic production of the backlight module 100 of the present embodiment can also meet the market's light and thin electronic production. Appeal. In detail, the first guide The thinner the thickness of the light panel 112, the second light guide plate 114, and the third light guide plate 116, the thinner the overall thickness of the backlight module 100, but the second light guide plate 114 is adjacent to one side of the first light source 120 and the second light source 130. The thickness of the first light source 120 and the second light source 130 is required to cover the light beam L from the first light source 120 and the second light source 130. For example, the thickness of the first light guide plate 112 falls within a range of, for example, 0.1 mm (mm) to 3 mm, and the thickness of the second light guide plate 114 falls within a range of, for example, 1 mm to 3 mm, and the thickness of the third light guide plate 116. For example, it falls within the range of 0.1 mm to 3 mm.

3A and 3B are partial top views of Fig. 2A. 4A and 4B are respectively a light field shape distribution diagram of Figs. 3A and 3B, in which the direction of the line segment A-A' is parallel to the first direction D1 in Fig. 3A. Referring to FIG. 3A and FIG. 4A , the first light source 120 and the second light source 130 of the backlight module 100 are not simultaneously turned on, for example. Further, when the backlight module 100 only turns on the first light source 120, as shown in FIG. 3A, the concentrating portion LCP can converge the light beam L from the first light source 120 to provide a relatively concentrated light field shape, thereby achieving The concentrating effect of the high-intensity collimated mode backlight module (as shown in Figure 4A).

In this embodiment, the condensing effect of the concentrating portion LCP concentrating portion LCP can automatically adjust the width W2 of each illuminating surface S2 in the first direction D1 and the width W1 of each illuminating surface S1 in the first direction D1. The ratio is reflected. For example, the ratio of the width W2 to the width W1 falls, for example, in the range of 1.1 to 6. Furthermore, in this embodiment, the first light source 120 can also be raised by adjusting the ratio of the distance D between the light exit surface S2 and the light incident surface S1 in the second direction D2 and the width W2 of the light exit surface S2 in the first direction D1. The light mixing effect. For example, the ratio of the distance D to the width W2 falls, for example, at 0.1. To the range of 10.

On the other hand, as shown in FIG. 3B and FIG. 4B, when the backlight module 100 only turns on the second light source 130, since the second light source 130 is disposed beside the connection surface C, the light beam L from the second light source 130 is directly incident to The second light guide plate 114 is provided to provide a relatively divergent light field shape, thereby achieving a wide-angle effect of the wide viewing angle mode backlight module (as shown in FIG. 4B). In this embodiment, the second light guide plate 114 may further include a plurality of hollow portions H recessed inwardly from the connecting surface C to further diverge the light field shape. The extending direction of each hollow portion H is, for example, perpendicular to the arrangement direction of the second light source 120 (ie, the first direction D1) and perpendicular to the arrangement direction of the second microstructures M2 (ie, the second direction D2). Furthermore, each of the second light sources 130 is provided, for example, corresponding to at least one hollow portion H.

In the present embodiment, the second light source 130 is provided corresponding to a triangular column-shaped hollow portion H, but the present invention is not limited thereto. 5A to 5C are various embodiments of the connection face corresponding to the second light source. As shown in FIG. 5A, each of the second light sources 130 may be disposed corresponding to the plurality of hollow portions, and the hollow portions H corresponding to the second light sources 130 are, for example, in a continuous distribution. Alternatively, as shown in FIG. 5B, the hollow portions H may not be in a continuous distribution, and maintain a distance d corresponding to the adjacent two hollow portions H of the respective second light sources 130. Further, as shown in FIG. 5C, the shape of the hollow portions H may also be semi-cylindrical, wherein the semi-cylindrical shape is not limited to half of the cylinder.

As can be seen from the above, the backlight module 100 of the present embodiment can have two light source modes, including a high-luminance collimation mode and a wide viewing angle mode, and the two light source modes can be switched according to the needs of the user. Specifically, when the user makes it alone When the electronic product of the backlight module 100 is applied, the backlight module 100 can be switched to a high-luminance collimation mode to have an anti-peep effect. Since the light beam L has a better convergence effect in the high-luminance collimation mode, that is, the energy is relatively concentrated and the energy consumption is relatively low, the first light source 120 can use a relatively low-power light source in order to achieve the desired luminance. In this way, it can meet the global demand for energy conservation. On the other hand, when a plurality of people view the electronic products of the backlight module 100, the backlight module 100 can be switched to the wide viewing angle mode, so that users of different viewing angles can view the image.

In addition, the backlight module 100 of the present embodiment may further include a diffusion sheet (not shown) disposed on the light guiding module 110 to reduce the visibility of the second microstructure M2.

6 is a schematic diagram of a backlight module in accordance with a second embodiment of the present invention. Referring to FIG. 6, the backlight module 200 of the present embodiment is substantially the same as the backlight module 100, and the same components are denoted by the same reference numerals and will not be described again. The main difference is that the second microstructure M2a of the light guiding module 110a of the present embodiment is not a continuous structure in the first direction D1. Through this structural design, the visibility of the second microstructure M2a can be reduced, thereby eliminating the arrangement of the aforementioned diffusion sheet.

FIG. 7 is a schematic diagram of a backlight module in accordance with a third embodiment of the present invention. Referring to FIG. 7, the backlight module 300 of the present embodiment is substantially the same as the backlight module 100, 200, and the same components are denoted by the same reference numerals and will not be described again. The main difference is that the backlight module 300 of the embodiment omits the arrangement of the third light guide plate 116, and the second bottom surface B2 is in contact with the first top surface T1. Under the structure of the double-layer light guide plate, the backlight module 300 of the embodiment may have a relatively thin thickness.

In this embodiment, the refractive index of the first light guide plate 112 may be smaller than the first Under the framework of the refractive index of the two light guide plates 114, the angle is designed by the first microstructure M1 and the second microstructure M2, and the position of the first microstructure M1 is changed by the first top surface T1 to control the light beam L. The direction of travel, so that the angle of the light beam L emitted by the second top surface T2 or the second microstructure M2 can be preferably controlled, for example, to cause the light beam L to exit at a small angle. For example, the first base angle θ1 of each of the first microstructures M1 of the present embodiment falls within a range of 30 degrees to 50 degrees, for example, and the second base angle θ2 of each second microstructure M2 falls, for example. In the range of 1 degree to 10 degrees.

Furthermore, the embodiment can also reduce the visibility of the second microstructure M2a by adopting the structural design of the second microstructure M2 in FIG. 6, thereby eliminating the arrangement of the diffusion sheet.

In summary, the backlight module of the present invention utilizes the concentrating portion to converge the light beam from the first light source to provide a relatively concentrated light field shape, thereby achieving the concentrating effect of the high-luminance collimated mode backlight module. In addition, by placing the second light source beside the connection surface, the light beam from the second light source is directly incident into the second light guide plate to provide a relatively divergent light field shape, thereby achieving a wide-angle effect of the wide viewing angle mode backlight module. . In addition, the backlight module of the present invention can better control the angle of the light beam emitted by the second top surface or the second microstructure through the arrangement of the first light guide plate and the second light guide plate, thereby improving the backlight module. Luminous efficiency.

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‧‧‧Backlight module

110‧‧‧Light guide module

120‧‧‧First light source

130‧‧‧second light source

112‧‧‧First light guide

114‧‧‧Second light guide

116‧‧‧ Third light guide

B1‧‧‧ first bottom surface

B2‧‧‧ second bottom surface

C‧‧‧ connection surface

D‧‧‧Distance

D1‧‧‧ first direction

D2‧‧‧ second direction

H‧‧‧镂空部

LCP‧‧‧The Department of Concentration

M1‧‧‧ first microstructure

M2‧‧‧Second microstructure

P1, P2‧‧‧ intercept

T1‧‧‧ first top

T2‧‧‧ second top surface

W1, W2‧‧‧ width

Claims (20)

A backlight module includes: a light guiding module, comprising: a first light guiding plate having a first bottom surface and a first top surface; and a second light guiding plate having a second bottom surface and a second top surface And a connecting surface connecting the second bottom surface and the second top surface, wherein the second bottom surface is located between the first top surface and the second top surface, the second light guide plate comprises a plurality of light collecting portions, each The concentrating portion has a light-incident surface and a light-emitting surface, the light-emitting surface is connected to the connecting surface, and the width of the light-emitting surface is greater than the width of the light-incident surface; a plurality of first microstructures are located on the first bottom surface, And protruding from the first bottom surface; and a plurality of second microstructures located on the second top surface and protruding outwardly from the second top surface; a plurality of first light sources located beside the light incident surfaces; And a plurality of second light sources located beside the connecting surface. The backlight module of claim 1, wherein the first light sources and the second light sources are arranged along a first direction, and the first microstructures are along a second direction perpendicular to the first direction The directions are aligned and respectively extend along the first direction, and the second microstructures are arranged along the second direction and respectively extend along the first direction. The backlight module of claim 2, wherein the first light sources and the second light sources are alternately arranged along the first direction. The backlight module of claim 2, wherein each of the light emitting surfaces The ratio of the width in the first direction to the width of each of the light incident surfaces in the first direction falls within the range of 1.1 to 6. The backlight module of claim 2, wherein a ratio of the distance from the light exit surface to the light incident surface in the second direction and the width of the light exit surface in the first direction falls between 0.1 and 10 In the range. The backlight module of claim 1, wherein the first microstructures are the same size and have a continuous distribution. The backlight module of claim 1, wherein the second microstructures have the same size, and the distribution density of the second microstructures on the second top surface increases with the distance from the connection surface. And increase. The backlight module of claim 1, wherein the second bottom surface is in contact with the first top surface, and the first light guide plate has a refractive index smaller than a refractive index of the second light guide plate. The backlight module of claim 8, wherein each of the first microstructures and each of the second microstructures are angle cylinders, each of the first microstructures having a 90 degree base angle and a first a bottom corner, the first bottom corner is in the range of 30 degrees to 50 degrees, each of the second microstructures has a 90 degree base angle and a second bottom corner, the second bottom corner being between 1 and 10 degrees Within the scope. The backlight module of claim 9, wherein the base angle of 90 degrees of each of the first microstructures is closer to the connection surface than the first bottom angle, and 90 degrees of each of the second microstructures. The bottom angle is closer to the connecting surface than the second bottom corner. The backlight module of claim 1, further comprising a third a light guide plate is disposed between the first light guide plate and the second light guide plate, and a refractive index of the first light guide plate and the second light guide plate is greater than a refractive index of the third light guide plate. The backlight module of claim 11, wherein the refractive index of the first light guide plate is the same as the refractive index of the second light guide plate. The backlight module of claim 11, wherein each of the first microstructures and each of the second microstructures are angle cylinders, each of the first microstructures having a 90 degree base angle and a first a bottom corner, the first bottom corner is in the range of 50 degrees to 70 degrees, each of the second microstructures has a 90 degree base angle and a second bottom corner, the second bottom corner being between 1 and 10 degrees Within the scope. The backlight module of claim 13, wherein the base angle of 90 degrees of each of the first microstructures is closer to the connection surface than the first bottom angle, and 90 degrees of each of the second microstructures. The bottom angle is closer to the connecting surface than the second bottom corner. The backlight module of claim 1, wherein the surface of the first microstructure not connected to the first bottom surface is a reflective surface. The backlight module of claim 1, wherein the second light guide plate further comprises a plurality of hollow portions recessed inwardly from the connection, and each of the second light sources is disposed corresponding to the at least one hollow portion. The backlight module of claim 16, wherein the extending direction of each of the hollow portions is perpendicular to an arrangement direction of the second light sources and perpendicular to an arrangement direction of the second microstructures. The backlight module of claim 16, wherein each of the second light sources is disposed corresponding to the plurality of hollow portions, and the hollow portions corresponding to the second light sources are A continuous distribution. The backlight module of claim 16, wherein each of the second light sources is disposed corresponding to the plurality of hollow portions, and maintains a distance corresponding to the adjacent two hollow portions of the second light sources. The backlight module of claim 1, further comprising a diffusion sheet disposed on the light guiding module.