TW201426122A - Back light module and display apparatus - Google Patents

Abstract

A back light module includes a light source and a light-guiding plate. The light-guiding plate has a light-entering surface, a bottom surface and a light-emitting surface opposite to the bottom surface and has a plurality of microstructures protruding from the bottom surface. The light source is disposed adjacent to the light-entering surface and emits a light to enter the light-guiding plate from the light-entering surface and emits out from the light-emitting surface. Each of the microstructures has a first part far away the light-entering surface and a second part close to the light-entering surface. A first angle of the first part and the bottom surface is between 10 degrees and 30 degrees. A second angle of the second part and the bottom surface is between 20 degrees and 50 degrees. The invention also discloses a display apparatus.

Description

Backlight module and display device

The invention relates to a backlight module and a display device.

Since the liquid crystal of the liquid crystal display itself does not emit light, in order to achieve the display effect, it is necessary to provide a light source to the display panel of the liquid crystal display, such as a backlight module, to supply a sufficient light intensity and a uniform distributed surface light source to display the display panel. Picture.

A backlight module includes a light source, a light guide plate, and a reflective sheet. The light source emits light from the light incident surface of one of the light guide plates to the light guide plate. The function of the light guide plate is to guide the light transmission direction, and the total reflection of the light inside the light guide plate, and the plurality of microstructures (such as the crater structure) located on one of the bottom surfaces of the light guide plate destroy the total reflection of the light. Light is emitted from one of the light-emitting surfaces of the light guide plate to form a uniform surface light source. In addition, the reflective sheet is disposed adjacent to the bottom surface of the light guide plate to reflect the light emitted from the bottom surface of the light guide plate back to the light guide plate to increase light utilization efficiency.

However, although the reflection sheet is disposed to reflect the light passing through the bottom surface of the light guide plate into the light guide plate, when the light is passed through the bottom surface of the light guide plate and reflected by the reflection sheet and is incident into the inside of the light guide plate, the light is emitted. At least two different media (light guide plate and air) penetration and one reflection will be performed. Since the transmittance of different media and the reflectance of the reflective sheet are both less than 1, the light energy loss (for example, loss of about 20%) is caused. . In addition, since the microstructures of the conventional light guide plate are hit by laser light on the mold core, and then through the injection machine The injection is formed, but due to the instability in the process, the height of the microstructures is also unstable, so that the energy distribution of the light is also unstable. In addition, the angle between the microstructures and the bottom surface is also difficult to control, and the total reflection cannot be formed, resulting in a decrease in the utilization of light.

Therefore, how to provide a backlight module and a display device can reduce the energy loss of light and improve the light utilization rate, and the backlight module and the display device have high luminous flux and brightness, which has become one of the important topics.

In view of the above problems, an object of the present invention is to provide a backlight module and a display device which can reduce light energy loss and improve light utilization efficiency, and have a high luminous flux and luminance of a backlight module and a display device.

To achieve the above objective, a backlight module according to the present invention includes a light source and a light guide plate. The light guide plate has a light incident surface, a bottom surface and a light emitting surface opposite to the bottom surface, and includes a plurality of microstructures protruding from the bottom surface, the light source is adjacent to the light incident surface, and a light is emitted from the light incident surface to the light guide plate. And emitting from the light-emitting surface, each microstructure has a first portion away from the light-incident surface and a second portion adjacent to the light-incident surface, and the first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees Between degrees, the second angle between the second portion and one of the bottom surfaces is between 20 degrees and 50 degrees. The invention also discloses a display device.

In one embodiment, the light guide plate is made of polycarbonate, and the first angle is between 20 degrees and 30 degrees.

In one embodiment, the material of the light guide plate is polymethyl methacrylate, and the first angle is between 10 degrees and 30 degrees.

In one embodiment, each microstructure has a length along a first direction and a height along a second direction, the length being between 2.5 and 8.4 times the height.

In one embodiment, the first angle of the microstructure that is further from the source is greater than the first angle of the microstructure that is closer to the source.

In one embodiment, when the light hits the first portion, the first portion totally reflects the light.

To achieve the above object, a display device according to the present invention includes a display panel and a backlight module. The backlight module is opposite to the display panel and includes a light source and a light guide plate. The light guide plate has a light incident surface, a bottom surface and a light emitting surface opposite to the bottom surface, and includes a plurality of microstructures protruding from the bottom surface, and the light source is adjacent to It is disposed on the light incident surface, and emits a light incident from the light incident surface to the light guide plate, and is emitted from the light exit surface, and each microstructure has a first portion away from the light incident surface and a second portion adjacent to the light incident surface The first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees, and the second angle between the second portion and the bottom surface is between 20 degrees and 50 degrees.

As described above, in the backlight module and the display device according to the present invention, the light guide plate includes a plurality of microstructures protruding from the bottom surface, and each of the microstructures has a first portion away from the light incident surface and one of the adjacent light incident surfaces. In the second part, the first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees, and the second angle between the second portion and the bottom surface is between 20 degrees and 50 degrees. . Therefore, the present invention can guide the incident light and cause total reflection by the arrangement of the plurality of microstructures, so as to reduce the energy loss caused by the light being emitted from the bottom surface of the light guide plate, thereby improving the utilization of the light and enabling the present invention. Invented backlight module Groups and display devices have high luminous flux and luminance.

Hereinafter, a backlight module and a display device according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings, wherein the same elements will be described with the same reference numerals.

1A and FIG. 1D, FIG. 1A and FIG. 1B are respectively a schematic cross-sectional view and a bottom view of a backlight module 1 according to a preferred embodiment of the present invention, and FIG. 1C is an enlarged view of a region C in FIG. 1B. FIG. 1D is a partial bottom perspective view of the backlight module 1. Here, FIGS. 1A and 1D show only one microstructure. In addition, FIGS. 1A to 1D are only schematic and do not show the true object ratio.

The backlight module 1 includes a light source 11 and a light guide plate 12.

As shown in FIG. 1A, the light guide plate 12 has a light incident surface I, a bottom surface B, and a light exit surface O opposite to the bottom surface B, and includes a plurality of microstructures 121 protruding from the bottom surface B. In this embodiment, the light guide plate 12 has two opposite bottom surfaces B and a light exit surface O. The light guide plate 12 is used to guide the direction of light travel, is made of a light transmissive material, and can be injection molded. The light transmissive material may, for example, comprise polycarbonate (Polycarbonate, PC, commonly known as plastic) or poly-methylmethacrylate (PMMA). Wherein, the refractive index of the light transmissive material is greater than the surrounding material (for example, air, the refractive index of which is about 1), and the light having the specific angle can form a total reflection effect at the boundary between the light guide plate 12 and the surrounding material, and can be formed by the light guide plate. The light incident on the side of the 12 (light-in plane I) is guided to the central portion to form a relatively even distribution. The form of light. Further, the cross-sectional shape of the light guide plate 12 may be, for example, a flat plate shape or a wedge shape as viewed in a first direction X. Here, the flat light guide plate 12 is taken as an example.

The light source 11 is adjacent to the light incident surface I, and emits a light L which is incident on the light guide plate 12 from the light incident surface I and is emitted from the light exit surface O. Here, the light incident surface I is adjacent to the bottom surface B and the light exit surface O. The light source 11 may include at least one light emitting diode, at least one organic light-emitting diode (OLED), at least one cold cathode fluorescent lamp (CCFL), or at least one Hot cathode fluorescent lamp (HCFL). Here, the light source 11 is exemplified by an LED light bar. The light emitting diode strip has a plurality of light emitting diodes disposed on a circuit substrate. The number of the light sources 11 in the embodiment is 1. However, in other embodiments, the two sets of light sources 11 may be disposed adjacent to the two light incident surfaces I of the light guide plate 12, respectively, and emit light L respectively. The light incident surface I of the light guide plate 12 is incident on the light guide plate 12.

In addition, each of the microstructures 121 protrudes from the bottom surface B, and has a first portion P1 away from the light incident surface I and a second portion P2 adjacent to the light incident surface I. The first portion P1 or the second portion P2 may include at least one slope, at least one curved surface, or any combination thereof. Further, the shape of each of the microstructures 121 may be formed by, for example, a corner cylinder, an elliptical cylinder, a corner cylinder, and a corner cylinder, or an elliptical cylinder and an elliptical cylinder. The top view shape of each microstructure 121 (ie, viewed in a second direction Z) may include a portion of an ellipse, a portion of a polygon (eg, a triangle or a quadrangle), or Its combination. In this embodiment, as shown in FIG. 1C and FIG. 1D, the shapes of the microstructures 121 are respectively formed by the shape of a corner cylinder and an elliptical cylinder, and the top view shape includes a part of the triangle. And a part of the arc (the intersection of the two). In addition, the second portion P2 of the present embodiment includes a combination of two inclined faces (a part of the inclined surface of the corner cylinder), and the first portion P1 includes a curved surface (a part of the curved surface of the elliptical cylinder).

In the case of the surface light source, since the intensity of the light L adjacent to the light incident surface I is strong in the light guide plate 12, the light is brighter, and the light L farther from the light incident surface I is weaker and the light is darker. Therefore, in order to control the light intensity and chromaticity of the light guide plate 12, and to make the light output more uniform, as shown in FIG. 1B, the distribution density of the microstructures 121 of the present embodiment adjacent to the light incident surface I is smaller than the light entering the light. The distribution density of face I. In addition, the microstructures 121 are discontinuous microstructures and may be randomly arranged. However, in other embodiments, the microstructures 121 may also be arranged in an array.

Referring again to FIGS. 1A and 1B, each of the microstructures 121 of the present invention has a length D along the first direction X and a height H along the second direction Z, and the length D is 2.5 of the height H. Doubled to 8.4 times. In addition, the length D of each microstructure 121 along the first direction X may be substantially equal to one width along a third direction Y. Here, the first direction X, the second direction Z, and the third direction Y are perpendicular to each other.

In addition, the first angle α between the first portion P1 and the bottom surface B is between 10 degrees and 30 degrees, and the second angle β between the second portion P2 and the bottom surface B is between 20 degrees and 50 degrees. between. Here, the first angle α is between 10 degrees and 30 degrees and the second angle β is between 20 degrees and 50 degrees. Respectively: 10 ° ≦ α ≦ 30 °, and 20 ° ≦ β ≦ 50 °. Among them, the farther from the light source 11, the larger the first angle α. In other words, in the microstructure 121 of the present invention, the first angle α formed between the first portion P1 and the bottom surface B is farther away from the light source 11, and the angle thereof is larger.

By using the β angle of the second portion P2 of the microstructure 121 and the bottom surface B, the amount of light entering the first portion P1 can be increased, and when the light L is emitted from the inside of the light guide plate 12 to the first portion P1 of the microstructure 121 The first portion P1 (which is a curved surface in this embodiment) can totally reflect the light L and enter the inside of the light guide plate 12, and is emitted from the light exit surface O. Therefore, the present invention can reduce the energy loss caused by the light L being emitted from the bottom surface B of the light guide plate 12, thereby improving the utilization of the light L. It is particularly noted that when the material of the light guide plate 12 is polycarbonate (PC), the preferred first angle α is between 20 degrees and 30 degrees. In addition, when the material of the light guide plate 12 is polymethyl methacrylate (PMMA), the preferred first angle α is between 10 degrees and 30 degrees, whereby the light guide plate 12 can be preferably provided. Luminous flux and brightness. Through actual experiments, it is proved that the average luminance of the conventional 2.7-inch backlight module with laser-structured light guide plate is 574 nits, and the average luminance of the light guide plate 12 of the microstructure-designed microstructure 121 of the present invention is 618 nits. Therefore, the luminance of the light emitted can be made higher than that of the conventional light guide plate by about 8%. In addition, in the embodiment, when the first angle α=20° and 40°≦β≦50°, the light guide plate 12 can have a high luminous flux and luminance.

In addition, in other implementations, the backlight module 1 may further include a reflective plate and or at least one optical film (not shown). The light-emitting plate may be disposed on one side of the bottom surface B of the light guide plate 12 to reflect the light emitted from the bottom surface B into the light guide plate 12 to further improve light utilization efficiency. The optical film can be, for example, a diffusion sheet, and can be disposed on one side of the light-emitting surface O of the backlight module 1 so that the light emitted from the backlight module 1 passes through the diffusion sheet to form a more uniform surface light source.

In addition, please refer to FIG. 2A to FIG. 2D respectively, which are respectively partially bottom perspective views of the backlight modules 1a to 1d of different aspects of the present invention.

As shown in FIG. 2A, the main difference between the backlight module 1a and the backlight module 1 is that the shapes of the microstructures 121a of the light guide plate 12a of the backlight module 1a are respectively formed by an elliptical cylinder and another elliptical cylinder. Intersected, and its top view shape contains a combination of two arcs. In addition, in the present embodiment, when the first angle α=20° and 40°≦β≦50°, the light guide plate 12a has a high luminous flux and luminance.

As shown in FIG. 2B, the main difference between the backlight module 1b and the backlight module 1 is that the shapes of the microstructures 121b of the light guide plate 12b of the backlight module 1b are respectively formed by the shapes of one corner cylinder and another corner cylinder. And its top view shape contains a combination of two polygons (constituting a quadrilateral). In addition, in the embodiment, when the first angle α=30° and 20°≦β≦30°, the light guide plate 12b has a high luminous flux and luminance.

As shown in FIG. 2C, the main difference between the backlight module 1c and the backlight module 1 is that the shapes of the microstructures 121c of the light guide plate 12c of the backlight module 1c are respectively formed by the shapes of one corner cylinder and another corner cylinder. The shape of the top view also includes a combination of two polygons (constituting a quadrilateral). In addition, in the embodiment, when the first angle α=20°, and 40°≦β≦50° When the light guide plate 12c has a high luminous flux and luminance.

As shown in FIG. 2D, the main difference between the backlight module 1d and the backlight module 1 is that the shapes of the microstructures 121d of the light guide plate 12d of the backlight module 1d are respectively formed by the shapes of an elliptical cylinder and a corner cylinder. The shape of the top view includes a combination of an arc and a quad. In addition, in the present embodiment, when the first angle α=20° and 30°≦β≦40°, the light guide plate 12d has a high luminous flux and luminance.

For the technical features of the other components of the backlight modules 1a to 1d, reference may be made to the same components of the backlight module 1 of FIGS. 1A to 1D, and details are not described herein again.

In addition, please refer to FIG. 3, which is a cross-sectional view of a display device 2 in accordance with a preferred embodiment of the present invention.

The display device 2 of the present invention includes a display panel 3 and a backlight module 4.

The backlight module 4 is opposite to the display panel 3 and includes a light source 41 and a light guide plate 42. The light guide plate 42 has a light incident surface I, a bottom surface B and a light exit surface O opposite to the bottom surface B, and includes a plurality of microstructures 421 protruding from the bottom surface B. The light source 41 is disposed adjacent to the light incident surface I, and emits a light L that is incident on the light guide plate 42 from the light incident surface I and is emitted from the light exit surface O. Each of the microstructures 421 has a first portion P1 away from the light incident surface I and a second portion P2 adjacent to the light incident surface I. The first angle between the first portion P1 and the bottom surface B is 10 degrees to Between 30 degrees, the second angle between the second portion P2 and the bottom surface B is between 20 degrees and 50 degrees. The backlight module 4 has all the technical features of the backlight module 1 or the backlight modules 1a to 1d, and details are not described herein.

In summary, in the backlight module and the display device according to the present invention, the light guide plate includes a plurality of microstructures protruding from the bottom surface, and each of the microstructures has a first portion away from the light incident surface and one of the adjacent light incident surfaces. In the second part, the first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees, and the second angle between the second portion and the bottom surface is between 20 degrees and 50 degrees. . Therefore, the present invention can guide the incident light and cause total reflection by the arrangement of the plurality of microstructures, so as to reduce the energy loss caused by the light being emitted from the bottom surface of the light guide plate, thereby improving the utilization of the light and enabling the present invention. The backlight module and the display device of the invention have high luminous flux and brightness.

The above is intended to be illustrative only and not limiting. Any equivalent modifications or alterations to the spirit and scope of the invention are intended to be included in the scope of the appended claims.

1, 1a~1d, 4‧‧‧ backlight module

11, 41‧‧‧ light source

12, 12a~12d, 42‧‧‧ light guide plate

121, 121a~121d, 421‧‧‧ microstructure

2‧‧‧Display device

3‧‧‧ display panel

B‧‧‧ bottom

D‧‧‧ Length

H‧‧‧ Height

I‧‧‧Into the glossy

L‧‧‧Light

O‧‧‧Glossy

P1‧‧‧ first part

P2‧‧‧ Part II

X‧‧‧ first direction

Y‧‧‧ third direction

Z‧‧‧second direction

Α‧‧‧first angle

Β‧‧‧second angle

1A and 1B are respectively a schematic cross-sectional view and a bottom view of a backlight module according to a preferred embodiment of the present invention; FIG. 1C is an enlarged schematic view of a region C in FIG. 1B; FIG. 1D is a partial view of the backlight module of the present invention; FIG. 2A to FIG. 2D are respectively partially bottom perspective views of a backlight module according to different aspects of the present invention; and FIG. 3 is a cross-sectional view of a display device according to a preferred embodiment of the present invention.

1‧‧‧Backlight module

11‧‧‧Light source

12‧‧‧Light guide plate

121‧‧‧Microstructure

B‧‧‧ bottom

D‧‧‧ Length

H‧‧‧ Height

I‧‧‧Into the glossy

L‧‧‧Light

O‧‧‧Glossy

P1‧‧‧ first part

P2‧‧‧ Part II

X‧‧‧ first direction

Z‧‧‧second direction

Α‧‧‧first angle

Β‧‧‧second angle

Claims (10)

A backlight module includes: a light source; and a light guide plate having a light incident surface, a bottom surface, and a light emitting surface opposite to the bottom surface, and including a plurality of microstructures protruding from the bottom surface, the light source is adjacent to the light source a light incident surface, and a light is incident from the light incident surface to the light guide plate, and is emitted from the light exit surface, each of the microstructures having a first portion away from the light incident surface and adjacent to the light incident surface In the second part, the first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees, and the second angle between the second portion and the bottom surface is between 20 degrees and 50 degrees. Between degrees. The backlight module of claim 1, wherein the light guide plate is made of polycarbonate, and the first angle is between 20 degrees and 30 degrees. The backlight module of claim 1, wherein the light guide plate is made of polymethyl methacrylate, and the first angle is between 10 degrees and 30 degrees. The backlight module of claim 1, wherein each of the microstructures has a length along a first direction and a height along a second direction, the length being between 2.5 and 8.4 of the height Between times. The backlight module of claim 1, wherein the first angle of the microstructure farther from the light source is greater than the first angle of the microstructure closer to the light source. The backlight module of claim 1, wherein the light is When the first portion is incident, the first portion totally reflects the light. A display device includes: a display panel; and a backlight module disposed opposite the display panel and including a light source and a light guide plate, the light guide plate having a light incident surface, a bottom surface, and a bottom surface opposite to the bottom surface a light emitting surface, and comprising a plurality of microstructures protruding from the bottom surface, the light source is disposed adjacent to the light incident surface, and emits a light from the light incident surface to the light guide plate, and is emitted from the light exit surface, each of which is micro The structure has a first portion away from the first light incident surface and a second portion adjacent to the light incident surface, and the first angle between the first portion and the bottom surface is between 10 degrees and 30 degrees. The second angle of the second portion and the bottom surface is between 20 degrees and 50 degrees. The display device of claim 7, wherein the light guide plate is made of polycarbonate, and the first angle is between 20 degrees and 30 degrees. The display device of claim 7, wherein the material of the light guide plate is polymethyl methacrylate, and the first angle is between 10 degrees and 30 degrees. The display device of claim 7, wherein each of the microstructures has a length along a first direction and a height along a second direction, the length being between 2.5 and 8.4 times the height between.