TW202240257A - Backlight module and display device - Google Patents

Abstract

The backlight module comprises a light source for generating light, a light guide plate and a first prism. The light guide plate comprises a light input surface, a light reverse input surface, a light reflecting surface and a light output surface, the light reverse input surface is opposite to the light input surface, the light reflecting surface and the light output surface are opposite to each other and are respectively connected with the light input surface and the light reverse input surface, and the light input surface faces the light source, so as to make the light enter the light guide plate and guide the direction of the light; The first prism is arranged on the reflecting surface, the first prism has a plurality of prism structures extending in the same direction, and each prism structure has a prism angle, wherein the prism angles face the reflecting surface of the light guide plate.

Description

Backlight module and display device

The invention relates to a backlight module and a display device, in particular to a backlight module which reduces noise light and improves light uniformity and a display device using the same.

With the advancement of science and technology, electronic devices equipped with liquid crystal displays have become an indispensable item in the life of modern people. However, when using such an electronic device in a place with other people, one's privacy may be peeped or the light and shadow emitted by the screen may interfere with others.

In order to solve the aforementioned problems, some operators provide a backlight module equipped with an optical Brightness Enhancement Film (BEF) on the light emitting direction of the light guide plate. Generally speaking, this type of backlight module is equipped with a laminated structure of two optical brightness enhancement films (such as two optical brightening films whose extension directions are orthogonal to each other), which can guide the light beam emitted by the light guide plate at a large angle to cover Within a specific angle range (for example -60° to 60°) of the front viewing angle, the overall light output intensity of the backlight module near the front viewing angle is improved. However, the backlight module adopting this type of double-layer BEF configuration cannot meet the specification requirements of the anti-peeping display device for the light collection of the backlight module. In addition, although there is also a backlight film set with a single-layer diaphragm that uses a reversed film to meet the anti-peeping requirements, but this kind of backlight film set tends to emit light from the light-incident and light-reflecting sides, becoming the incident light. Noisy light reflected from the incident light side is not conducive to the uniformity of the backlight module.

The purpose of the present invention is to provide a backlight module set under the reflective surface of the light guide plate to set the direction of the light guide plate, which is the first plate, to reduce or filter the reflection surface of the light guide plate and enter at a large angle. The light of the next film.

In order to achieve the above object, the present invention provides a backlight module, which includes: a light source; The light-incident surface, the reflective surface and the light-emitting surface are opposite to each other and are respectively connected to the light-incident surface and the light-reflective surface, and the light-incidence surface faces the light source, so that the light enters the light guide plate and guides the light direction of travel; and a first braided sheet, disposed on the reflective surface, the first braided sheet has a plurality of braided structures extending in the same direction, each of the braided structures has a braided angle, wherein the edges The mirror angle is directed toward the reflective surface of the light guide plate.

In some embodiments of the present invention, the reflective surface of the light guide plate is formed with a plurality of light guide structures.

In some embodiments of the present invention, each of the light guide structures has a light-facing surface and a backlight surface, the light-facing surface forms a first included angle with the reflective surface, and the backlight surface forms a second included angle with the reflective surface , and the first included angle α and the second included angle β are both acute angles, and the first included angle is smaller than the second included angle.

In some embodiments of the present invention, it may further include: a second scalloped sheet, disposed on the light-emitting surface, the second slatted sheet is a reversed scalloped sheet, and the second slatted sheet has a plurality of reversed ribs extending along the same direction A mirror structure, each of the reversed beam structures has a reversed beam angle, wherein the reversed beam angles are directed toward the light-emitting surface of the light guide plate, and the extension of the reversed beam structures of the second mirror plate The direction is perpendicular to the extension direction of the braided structures of the first braided sheet.

In some embodiments of the present invention, each braided structure of the first braided sheet extends along a first direction, the light incident surface of the light guide plate, the light source, and the opposite edges of the second braided sheet The mirror structure extends along a second direction, and the first direction is perpendicular to the second direction.

In some embodiments of the present invention, the aforementioned backlight module may further include: a light-absorbing film disposed on a side of the first film opposite to the light guide plate.

In the aforementioned embodiments of the invention, the light-absorbing film can be a black film or a foggy black film.

Another object of the present invention is to provide a display device, which is provided with a slit under the reflective surface of the light guide plate of the backlight module, that is, a first slit in the direction of the light guide plate, so as to reduce or filter the light passing through the light guide plate. Light rays that reflect off the surface and enter the lower plate at large angles.

In order to achieve the above object, the present invention provides a display device, the structure of which includes: the backlight module in the above-mentioned embodiments and a display panel disposed on the side of the backlight sheet facing away from the light guide plate.

The present invention has at least the following characteristics: the backlight module of the present invention utilizes the lower panel on the side of the reflective surface of the light guide plate, that is, the first panel, and the lower panel angle of the lower panel is arranged toward the light guide plate , to filter the light entering the lower panel at a large angle. The light at this large angle is not easily fully reflected by the lower panel, so it can pass through the lower panel without returning to the light guide plate, which helps to solve the problem of light incident and reflective side After the noisy light (compared to the light at the forward viewing angle), the bright lines or bright bands on the incident light and reflected light sides are more convergent. The present invention can further apply the light-absorbing film on the other side of the light-guiding plate at the lower angle to achieve better light-filtering effect.

1: Backlight module

11: Light source

12: Light guide plate

121: light incident surface

122: reflective surface

123: reflective surface

124: light emitting surface

125: Light guide structure

1251: face to the light

1252: backlit surface

13: The first piece of 稜鏡

131: 稜鏡 structure

1311: 稜鏡角

14: The second patch

141: Reversed 稜鏡 structure

1411: Inverse angle

15: Absorbing film

2: Display device

21: Display panel

A, B: extension direction

L1, L2: light

P: imaginary surface

X: first direction

Y: the second direction

α: first included angle

β: second included angle

[Fig. 1a] is a schematic front view cross-sectional view of a backlight module according to a first embodiment of the present invention;

[Fig. 1b] is a schematic left view of Fig. 1a;

[Fig. 1c] is a partial cross-sectional enlarged view of Fig. 1a;

[Fig. 1d] is a partial cross-sectional enlarged view of Fig. 1b;

[Fig. 2] is a schematic front view of a backlight module according to a second embodiment of the present invention;

[FIG. 3] is a top view of the relative relationship between the angles between the extension directions of the first 稜鏡 structure and the second 稜鏡 structure according to a second embodiment of the present invention;

[ FIG. 4 ] is a three-dimensional schematic diagram of the relative relationship between the angles between the first pleated structure and the light incident surface of the light guide plate, the light source, and the extending direction of the second pleated structure according to a second embodiment of the present invention;

[ Fig. 5 ] is a front sectional view of a display device according to an embodiment of the present invention.

The embodiments of the present invention are described in detail below in conjunction with the drawings. The attached drawings are mainly simplified schematic diagrams, which only schematically illustrate the basic structure of the present invention. Therefore, only components related to the present invention are marked in these drawings. , and the displayed components are not drawn according to the number, shape, size ratio, etc. of the actual implementation. The actual size of the actual implementation is a selective design, and the layout of the components may be more complicated.

The following descriptions of the various embodiments refer to the accompanying drawings to illustrate specific embodiments in which the present invention may be practiced. The directional terms mentioned in the present invention, such as "upper", "lower", "front", "rear", etc., are only referring to the directions of the attached drawings. Therefore, the directional terms used are used to illustrate and understand the application, but not to limit the application. Also, in the specification, unless it is clearly described to the contrary, the word "comprising" will be understood as meaning including the stated elements, but not excluding any other elements.

Please refer to Figure 1a and Figure 1b. The main structure of the backlight module 1 of the first embodiment includes: a light source 11 , a light guide plate 12 , and a first film 13 . The light source 11 can generate a light. The light guide plate 12 includes a light incident surface 121, a light incident surface 122, a reflective surface 123 and a light exit surface 124, the light reflective surface 122 is opposite to the light incident surface 121, the reflective surface 123 and the The light emitting surfaces 124 are opposite to each other and are respectively connected to the light incident surface 121 and the light incident surface 122. The light incident surface 121 faces the light source 11, so that the light enters the light guide plate 12 and is guided in the light guide plate 12. The direction of travel of the light: the first glazing sheet 13 is disposed on the side of the light guide plate 12 close to the reflective surface 123, the first glazing sheet 13 has a plurality of glazing structures 131 extending in the same direction, each of which The angled structures 131 have an angled angle 1311 , wherein the angled angles 1311 are facing the reflective surface 123 of the light guide plate 12 . In this embodiment, through the disposition of the corners 1311 of the first diaphragm 13 towards the light guide plate 12, the light entering the first diaphragm 13 at a large angle is filtered, and the light with a large angle is not easily captured by the first diaphragm 13. A sliver 13 is totally reflected, so it can pass through the first slit 13 without returning to the light guide plate 12, which helps to solve the noise light on the light-incident and light-incident sides (relative to the light at the forward viewing angle), Make the bright lines or bright bands on the light incident side and the light incident side side more convergent.

As shown in FIG. 1 c , in order to improve the light scattering uniformity of the light guide plate 12 , a plurality of light guide structures 125 are formed on the reflective surface 123 of the light guide plate 12 .

Further, as shown in FIG. 1c and in combination with FIG. 4 , in this embodiment, it can be additionally defined that each braided structure 131 of the first braided sheet 13 extends along a first direction X, and the entrance of the light guide plate 12 The optical surface 121 and the light source 11 extend along a second direction Y, and the first direction X is perpendicular to the second direction Y. According to the structure of the aforementioned backlight module 1, light is generated by the light source 11, and the light enters the light guide plate 12 from the light incident surface 121. The light L1 shown in the figure illuminates the light guide plate 12 , it will be refracted through the reflective surface 123 of the light guide plate 12 , and enter the first film 13 . Afterwards, please refer to FIG. 1d, from the light incident surface 121 of the light guide plate 12, the light L1 will be refracted by one of the surfaces of each of the scalloped structures 131 to produce different traveling directions in the first scalloped sheet 13, and then reflected from the bottom surface of the first slatted sheet 13 to be reflected from each of the slatted sheets 13. The other surface of the structure 131 leaves the first sheet 13 and then re-enters the light guide plate 12; and when some of the light guide plate 12 shown in FIG. out of the reflective surface 123, and incident to the first prism 13 at a large angle, the light L2 with a large angle has a relatively large angle with the first prism 13, relatively, the ray L2 is opposite to the first prism The included angle between the surface normals of the lens 13 is relatively small and not easily greater than the total reflection angle of the first prism 13, so that the light L2 is not easily totally reflected by the first prism 13, but easily penetrates the first prism. lens 13, so the light L2 will not return to the light guide plate 12 like the light L1. Especially on the light incident surface 121 and the light incident surface 122 of the light guide plate 12, these large-angle light rays L2 are the main source of noise light. If the light rays L2 can be prevented from returning to the light guide plate, it will help to solve the problem. The noise light at a large angle between the light-incident surface 121 and the light-incident surface 122 of the light plate 12 makes the bright lines on both sides of the light-incident surface 121 and the light-incident surface 122 more convergent.

In order to prevent the above-mentioned light L2 that penetrates the first flake 13 from returning to the first flake 13, a light absorbing light can be arranged on the outside of a plane surface of the first flake 13 opposite to the flake structure 131. A diaphragm 15, such as a black diaphragm or a foggy black diaphragm, is used to suppress reflection of light, as shown in FIG. 1c. With this design, the noise light at a large angle between the light-incident surface 121 and the light-incident surface 122 of the light guide plate 12 can be further absorbed by the light-absorbing film 15 after penetrating the first film 13, and the incident light The convergence effect of the bright lines on both sides of the surface 121 and the light-reflecting surface 122 can be further strengthened to reduce viewing angle noise. Besides, another main purpose of the light-absorbing film 15 is to block stray light, including ambient light. If the light-absorbing film 15 is missing, it is easy to penetrate these light guide plates or films visually, so that the eyes can easily observe the holes on the back plate of the backlight module.

Figures 2, 3, and 4 show the application of a second embodiment of the present invention to a high-directivity backlight module. The configuration is the same as the first embodiment. When this structure is applied to a high-directivity backlight module, the high-directivity light guide plate is mainly combined with a turning film (TF). Please refer to FIG. 1c, the high-directivity light guide plate is designed to have a light-facing surface 1251 and a back-light surface 1252 for each of the aforementioned light-guiding structures 125, the light-facing surface 1251 forms a first angle α with the imaginary surface P, and The imaginary plane P is parallel to the reflective surface 123 (that is, the light-receiving surface 1251 forms a first angle α with the reflective surface 123), and similarly, the backlight surface 1252 forms a second angle β with the imaginary plane P. (That is, the backlight surface 1252 and the reflective surface 123 form a second included angle β), and the first included angle α and the second included angle β are both acute angles, and the first included angle α is smaller than the second included angle β. As for the Turning Film (Turning Film, TF), as shown in Figures 2, 3, and 4, in the second embodiment, a second turning film 14 is arranged on the side of the light-emitting surface 124 of the light guide plate 12, and the second turning film 14 The scalloped sheet 14 is in the form of a reversed scalloped sheet. The second scalloped sheet 14 has a plurality of reversed scalloped structures 141 extending in the same direction, and each of these reversed slatted structures 141 has a reversed slatted angle 1411, wherein the The reversed angles 1411 are directed toward the light-emitting surface 124 of the light guide plate 12, and the extension direction B of the reversed structures 141 of the second laminated sheet 14 is perpendicular to the extended direction B of the first laminated sheet 131. The extension direction A of the structure 131 .

In detail, please refer to FIG. 4 , each of the scalloped structures 13 of the first slatted sheet 13 extends along the first direction X, and the incident surface 121 of the light guide plate 12 , the light source 11 , and the second The reversed-shaped structures 141 of the two-shaped sheet 14 extend along a second direction Y, and the first direction X is perpendicular to the second direction Y.

According to the above-mentioned design structure of the high directivity backlight module, the light can be allowed to leave the light guide plate 12 with high directivity by utilizing the asymmetric shape of the included angle of each light guide structure 125, and then Through the reverse film function of the second film 14, the light is directly emitted in the forward direction, reducing the non-direct or oblique light output, so as to achieve the purpose of the high directivity backlight module and have the effect of anti-peeping.

As shown in Figure 5. The structure of the display device 2 of this embodiment includes: a backlight module 1 as in any of the aforementioned embodiments; One side of light board 12.

In summary, it can be seen from the above embodiments that the present invention uses the configuration of the lower panel on the side of the light guide plate close to the reflective surface, that is, the first panel, and the angle of the panel of the lower panel faces the light guide plate, so that the filter can be filtered at a large angle. The light entering the lower panel, because the light is perpendicular to the optical path in the direction of the lower panel, is not easy to be totally reflected by the lower panel and thus penetrates the lower panel without returning to the light guide plate, which helps to solve the problem of entering the lower panel. The noise light on the light and anti-light sides relative to the light at the forward viewing angle makes the bright lines or bright bands on the light and anti-light sides more convergent.

The embodiments disclosed above are only illustrative of the principles, features and effects of the present invention, and are not intended to limit the scope of the present invention. Any person familiar with the art can, without departing from the spirit and scope of the present invention, Modifications and changes are made to the above-mentioned embodiments. Any equivalent change and modification accomplished by using the content disclosed in the present invention should still be covered by the scope of the following patent application.

11: Light source

12: Light guide plate

121: light incident surface

123: reflective surface

124: light emitting surface

125: Light guide structure

1251: face to the light

1252: backlit surface

13: The first piece of 稜鏡

131: 稜鏡 structure

15: Absorbing film

L1, L2: light

P: imaginary surface

α: first included angle

β: second included angle

Claims (9)

A backlight module, comprising: a light source for generating a light; A light guide plate, including a light incident surface, a light reflection surface, a reflection surface and a light exit surface, the light reflection surface is opposite to the light entrance surface, the reflection surface and the light exit surface are opposite to each other and are respectively connected the incident surface and the reflective surface, the incident surface faces the light source, and is used to allow the light to enter the light guide plate and guide the traveling direction of the light; and a first scalloped sheet, arranged on the reflective surface, the first slatted sheet has a plurality of slatted-striped structures extending along the same direction, each of these slatted-screwed structures has a stern-screwed angle, wherein these slatted-screwed angles are oriented toward the reflective surface of the light guide plate. The backlight module as claimed in claim 1, wherein the reflective surface of the light guide plate is formed with a plurality of light guide structures. The backlight module as described in Claim 2, wherein each of the light guide structures has a light-facing surface and a backlight surface, the light-facing surface and the reflective surface form a first angle, and the backlight surface and the reflective surface form a A second included angle, and both the first included angle and the second included angle are acute angles, and the first included angle is smaller than the second included angle. The backlight module as described in any one of claims 1 to 3, further comprising: A light-absorbing film is arranged on the side of the first film opposite to the light guide plate. The backlight module according to claim 4, wherein the light-absorbing film is a black film or a foggy black film. The backlight module as described in claim 1 further includes: A second scalloped sheet, arranged on the light-emitting surface, the second slatted sheet is an inverted scalloped sheet, and the second slatted sheet has a plurality of reversed slatted structures extending in the same direction, and each of the reversed slatted structures has a Reverse angles, wherein the reverse angles are towards the light-emitting surface of the light guide plate, and the second angle is The extending direction of the reversed braid structures is perpendicular to the extending direction of the braid structures of the first braided sheet. The backlight module as described in claim 6, wherein each fret structure of the first fretboard extends along a first direction, the incident surface of the light guide plate, the light source, and the second fretboard The reversed-shaped structures extend along a second direction, and the first direction is perpendicular to the second direction. The backlight module as described in Claim 1, wherein each scalloped structure of the first slatted sheet extends along a first direction, the light incident surface of the light guide plate and the light source extend along a second direction, And the first direction is perpendicular to the second direction. A display device comprising: A backlight module as described in any one of claims 1 to 8; a second patch, arranged on the light-emitting surface, the second patch is a reverse patch; and A display panel is arranged on the side of the reverse film facing away from the light guide plate.

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