CN114419994A

CN114419994A - Backlight module

Info

Publication number: CN114419994A
Application number: CN202210058587.6A
Authority: CN
Inventors: 郑慧君; 郭运涛
Original assignee: AU Optronics Suzhou Corp Ltd; AU Optronics Corp
Current assignee: AU Optronics Suzhou Corp Ltd; AU Optronics Corp
Priority date: 2022-01-12
Filing date: 2022-01-12
Publication date: 2022-04-29
Also published as: TWI844001B; TW202328785A

Abstract

The invention discloses a backlight module, which comprises a plurality of light sources, a diffusion plate and a plurality of shading composite layers. The diffusion plate is located above the light source. The shading composite layer is positioned on the diffusion plate and respectively corresponds to the light source positions. The width of each light-shielding composite layer is gradually reduced from the diffusion plate to the direction far away from the light source.

Description

Backlight module

Technical Field

The invention relates to a backlight module.

Background

In recent years, the variety of light sources used in backlight modules has been increasing. For example, mini LEDs can be used in backlight modules of display devices. To avoid the area corresponding to the light source being too bright, a diffuser plate is generally disposed above the light source to make the light uniform.

Although the ink Pattern (Pattern) on the diffuser plate can have the effect of blocking the light from the light source, due to the current screen printing technology, the thickness of the ink used to form the Pattern of the diffuser plate is mostly flat or concave, so that the light passing through the ink Pattern is not uniform, and the situation that the light is directly above the light source and the edge is dark is easily caused. When the backlight module is turned on, a defect picture, such as an LED mura, caused by uneven brightness may be observed.

Disclosure of Invention

One aspect of the present invention is a backlight module.

According to some embodiments of the present invention, a backlight module includes a plurality of light sources, a diffuser plate, and a plurality of light-shielding composite layers. The diffusion plate is located above the light source. The shading composite layer is positioned on the diffusion plate and respectively corresponds to the light source positions. The width of each light-shielding composite layer is gradually reduced from the diffusion plate to the direction far away from the light source.

In some embodiments, each of the light-shielding composite layers includes a plurality of light-shielding sub-layers. The width of the uppermost layer of the sub-shading layers is larger than that of the corresponding light source.

In some embodiments, the light sub-shielding layers have different shapes.

In some embodiments, the light sub-shielding layers have the same thickness.

In some embodiments, the sub-light-shielding layers have different transmittance.

In some embodiments, the sub-shading layer includes a lower layer and an upper layer on the lower layer, and the density of the upper layer is greater than that of the lower layer.

In some embodiments, the light sources are each within a forward projection profile of the light-blocking composite layer.

In some embodiments, a distance between two adjacent light sources along the first direction is smaller than a distance between two adjacent light sources along the second direction.

In some embodiments, the longitudinal direction of each light-shielding composite layer is the same as the first direction.

In some embodiments, the width direction of each light-shielding composite layer is the same as the second direction.

In the above embodiments of the present invention, the backlight module has the light-shielding composite layer located on the diffuser plate and corresponding to the light source respectively, and the width of the light-shielding composite layer gradually decreases from the diffuser plate to the direction away from the light source, so the central region of the light-shielding composite layer is thicker, and the edge region is thinner, so that the central region of the light-shielding composite layer has a better light-shielding effect. Therefore, when the light source below the shading composite layer emits light, although the light source irradiates more light in the central area of the shading composite layer and less light irradiates the edge area of the shading composite layer, the central area of the shading composite layer can shade more light and the edge area can shade less light due to the width change of the shading composite layer, so that the effect of light homogenization is achieved, and the problem of defective pictures (such as LED mura) caused by uneven brightness can be solved. In addition, the shading composite layer can be formed by printing for many times, and is convenient to manufacture.

The invention is described in detail below with reference to the drawings and specific examples, but the invention is not limited thereto.

Drawings

Aspects of this disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

FIG. 1 is a cross-sectional view of a backlight module according to an embodiment of the invention.

Fig. 2 is a perspective view of the light-shielding composite layer of fig. 1.

Fig. 3 is a perspective view of a light-shielding composite layer according to another embodiment of the present invention.

Fig. 4 is a top view of a light-shielding composite layer according to still another embodiment of the present invention.

Fig. 5 is a plan view showing the light-shielding composite layer of fig. 4 after the formation of the lower layer and before the formation of the upper layer.

Fig. 6 is a top view of a light-shielding composite layer according to still another embodiment of the present invention.

Wherein the reference numerals

100: backlight module

110: light source

120: diffusion plate

130, 130a, 130b, 130 c: shading composite layer

132, 132a, 132 b: light sub-shielding layer

134, 134a, 134 b: light sub-shielding layer

136a, 138 a: light sub-shielding layer

140: substrate

150: packaging adhesive

160: colloid

A: extent of contour

D: direction of rotation

D1: a first direction

D2: second direction

d1, d 2: distance between two adjacent plates

H: thickness of

W1, W2, W3: width of

Detailed Description

The following detailed description of the embodiments of the present invention with reference to the drawings and specific examples is provided for further understanding the objects, aspects and effects of the present invention, but not for limiting the scope of the appended claims.

The following disclosure of embodiments provides many different embodiments, or examples, for implementing different features of the provided subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. Of course, these examples are merely examples and are not intended to be limiting. Further, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Spatially relative terms, such as "below … …", "below … …", "below", "above … …", "above", and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly as such.

Fig. 1 is a cross-sectional view of a backlight module 100 according to an embodiment of the invention. Fig. 2 is a perspective view of the light blocking composite layer 130 of fig. 1. Referring to fig. 1 and 2, the backlight module 100 includes a plurality of light sources 110, a diffuser 120 and a plurality of light-shielding composite layers 130. The light source 110 may be a point light source, such as an LED or Mini LED. The diffusion plate 120 is positioned above the light sources 110. The light-shielding composite layer 130 is disposed on the diffusion plate 120 and corresponds to the light sources 110. As shown in fig. 1, the light blocking composite layer 130 is aligned in the vertical direction in the same number as the light sources 110. In the present embodiment, the backlight module 100 has six light-shielding composite layers 130 and six light sources 110, but the invention is not limited thereto. In addition, the width of each light-shielding composite layer 130 gradually decreases from the diffusion plate 120 to the direction D away from the light source 110. Such a design allows the thickness of the light-shielding composite layer 130 to be greater in the central region than in the edge region. Herein, the central region of the light shielding composite layer 130 may mean a region directly above the light source 110, and the edge region of the light shielding composite layer 130 may mean a region where the light source 110 surrounds the central region and does not overlap the light source 110 in a vertical direction.

The light-shielding composite layer 130 can be formed by multiple screen printing, for example, two screen printing, to form the structure shown in fig. 2. The material of the light blocking composite layer 130 may be ink. In the present embodiment, each light-shielding composite layer 130 includes a plurality of sub-light-shielding

layers

132 and 134. The width W1 of the sub-light shielding layer 132 of the lower layer is greater than the width W2 of the sub-light shielding layer 134 of the upper layer, so that the thickness of the light shielding composite layer 130 in the central region is greater than that in the edge region. For example, the

sub-shielding layers

132 and 134 may have the same thickness H. Thus, the central region of the light-shielding composite layer 130 has a thickness H twice as large as the total thickness 2H of the sub-light-shielding

layers

132 and 134, for example, 15 to 45 μm, and the edge region of the light-shielding composite layer 130 has a thickness H as large as the thickness H of the sub-light-shielding layer 132 below.

Specifically, since the backlight module 100 has the light-shielding composite layer 130 disposed on the diffusion plate 120 and corresponding to the light sources 110, and the width of the light-shielding composite layer 130 gradually decreases from the diffusion plate 120 to the direction D away from the light sources 110, the light-shielding composite layer 130 has a thicker central region and a thinner edge region, so that the central region of the light-shielding composite layer 130 has a better light-shielding effect. Thus, when the light source 110 below the light-shielding composite layer 130 emits light, although more light is emitted from the light source 110 to the central region of the light-shielding composite layer 130 and less light is emitted from the edge region of the light-shielding composite layer 130, the width of the light-shielding composite layer 130 varies, so that more light can be shielded from the central region of the light-shielding composite layer 130 and less light can be shielded from the edge region, thereby achieving the effect of light uniformity and overcoming the problem of defective pictures (such as LED mura) caused by non-uniform brightness. The light-shielding composite layer 130 can be formed by printing for many times, and is convenient to manufacture.

In the present embodiment, the width W2 of the uppermost sub-light-shielding layer (i.e., the sub-light-shielding layer 134) is greater than the width W3 of the corresponding light source 110. With such a design, the light emitted from the light source 110 directly upward can pass through the sub-light-shielding layer 132 and the sub-light-shielding layer 134, so as to improve the light-shielding effect directly above the light source 110. Since the uppermost sub-light shielding layer 134 having the minimum width W2 is wider than the light source 110 and the other sub-light shielding layers 132 are also wider than the light source 110, the light sources 110 in fig. 1 can be within the orthographic projection profile a of the light shielding composite layer 130, respectively. The outline area a is the area between the two dashed lines in fig. 1.

In the present embodiment, the sub-light-shielding

layers

132 and 134 may have the same shape, such as a circle, but not limited thereto, and a rectangle or other kinds of polygons may also be used. In addition, the sub-light-shielding

layers

132 and 134 may have the same density and the same transmittance, such as 85% to 95%, but not limited thereto. In other embodiments, the sub-shielding layers may have different shapes, densities and transmittances (as will be described in fig. 4).

In addition, referring to fig. 1, the backlight module 100 may further include a substrate 140, a packaging adhesive 150 and an adhesive 160. The light source 110 is disposed on the substrate 140. The substrate 140 may be a circuit board to supply power to the light source 110. The encapsulant 150 covers the light source 110, providing protection and insulation effects and preventing moisture from entering. The gel 160 may be disposed on the inner surface of the housing to support the substrate 140 and provide a buffer effect.

It is to be understood that the connection, materials and functions of the elements described above will not be repeated and are described in detail. In the following description, other types of light-shielding composite layers will be described.

Fig. 3 is a perspective view of a light-shielding composite layer 130a according to another embodiment of the present invention. The light-shielding composite layer 130a can be formed by multiple screen printing, for example, four screen printing, to form the structure shown in fig. 3. This embodiment differs from the embodiment of fig. 2 in that the light-shielding composite layer 130a includes four sub-light-shielding

layers

132a, 134a, 136a, and 138 a. The width of the sub-shielding layer 132a is greater than that of the sub-shielding layer 134a, the width of the sub-shielding layer 134a is greater than that of the sub-shielding layer 136a, and the width of the sub-shielding layer 136a is greater than that of the sub-shielding layer 138 a. That is, the width of the light-shielding composite layer 130a increases from the sub-light-shielding layer 132a to the sub-light-shielding layer 134a, the sub-light-shielding layer 136a, and the sub-light-shielding layer 138a in sequence, so that the thickness of the light-shielding composite layer 130a in the central region is greater than that in the peripheral region, thereby achieving the effect of light uniformity.

The light-shielding composite layer 130a of fig. 3 can be applied to the backlight module 100 of fig. 1, for example, the light-shielding composite layer 130 of fig. 1 can be replaced to correspond to the light source 110.

Fig. 4 is a top view of the light-shielding composite layer 130b according to still another embodiment of the present invention. The light-shielding composite layer 130b can be formed by multiple screen printing, for example, two screen printing, to form the structure shown in fig. 4. This embodiment is different from the embodiment of fig. 2 in that the sub-light-shielding

layers

132b and 134b of the light-shielding composite layer 130b have different shapes and have different transmittances. In this embodiment, the sub-light-shielding layer 132b is a lower layer, the sub-light-shielding layer 134b is an upper layer on the lower layer, and the density of the upper layer is higher than that of the lower layer. For example, the sub-light-shielding layer 132b is a circle formed by dot-shaped ink, and the sub-light-shielding layer 134b is an octagon (16-sided polygon) formed by planar-shaped ink, so that the transmittance of the sub-light-shielding layer 134b is smaller than that of the sub-light-shielding layer 132b, which is beneficial for shielding light directly above the light source 110 (see fig. 1).

In addition, the width of the sub-light shielding layer 132b is greater than that of the sub-light shielding layer 134 b. Therefore, the thickness of the light-shielding composite layer 130b in the central region is greater than that in the edge region, thereby achieving the effect of light homogenization. The light-shielding composite layer 130b of fig. 4 can be applied to the backlight module 100 of fig. 1, for example, the light-shielding composite layer 130 of fig. 1 can be replaced to correspond to the light source 110.

In the following description, a forming step of the light-shielding composite layer 130b will be described.

Fig. 5 is a plan view showing the light-shielding composite layer 130b of fig. 4 after the lower layer (the sub-light-shielding layer 132b) is formed and before the upper layer (the sub-light-shielding layer 134b) is formed. Referring to fig. 4 and 5, the diffuser 120 may be formed with a sub-shielding layer 132b by dot-shaped screen printing ink. Next, the diffusion plate 120 may be formed on the light shielding layer 134b on the light shielding layer 132b through another planar screen printing ink. Thus, the light-shielding composite layer 130b of fig. 4 is obtained.

FIG. 6 is a top view of a light-shielding composite layer 130c according to still another embodiment of the invention. The light-shielding composite layer 130c has an outer contour as shown in FIG. 6, and the number of the sub-light-shielding layers stacked is not limited to the invention. The light-shielding composite layer 130c corresponds in position to the light source 110 such that the light source 110 is covered by the light-shielding composite layer 130 c. In the present embodiment, a distance D1 between two adjacent light sources 110 along the first direction D1 is smaller than a distance D2 between two adjacent light sources 110 along the second direction D2, wherein the first direction D1 is perpendicular to the second direction D2. The length direction of each light-shielding composite layer 130c is the same as the first direction D1, and the width direction of each light-shielding composite layer 130c is the same as the second direction D2.

With this arrangement, although the distance D1 between the two light sources 110 arranged along the first direction D1 is short, and the luminance of the region is bright, the light-shielding composite layer 130c extending along the first direction D1 is arranged above, so that excessive light can be effectively shielded, and the effect of light homogenization can be achieved. In addition, the distance D2 between the two light sources 110 arranged in the second direction D2 is long, so that the luminance of the area is dark, but the light-shielding composite layer 130c extending in the first direction D1 is arranged above, so that only a small amount of light is shielded in the second direction D2, thereby achieving the effect of light uniformity. The light-shielding composite layer 130c of fig. 6 can be applied to the backlight module 100 of fig. 1, for example, the light-shielding composite layer 130 of fig. 1 can be replaced to correspond to the light source 110.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it should be understood that various changes and modifications can be effected therein by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A backlight module, comprising:

a plurality of light sources;

a diffusion plate located above the light sources; and

and the plurality of shading composite layers are positioned on the diffusion plate and respectively correspond to the light sources, wherein the width of each shading composite layer is gradually reduced from the diffusion plate to the direction far away from the light sources.

2. The backlight module as claimed in claim 1, wherein each of the light-shielding composite layers includes a plurality of light-shielding sub-layers, and a width of an uppermost layer of the light-shielding sub-layers is greater than a width of the corresponding light source.

3. The backlight module as claimed in claim 2, wherein the sub-light-shielding layers have different shapes.

4. The backlight module as claimed in claim 2, wherein the sub-light-shielding layers have the same thickness.

5. The backlight module as claimed in claim 2, wherein the sub-light-shielding layers have different transmittances.

6. The backlight module as claimed in claim 2, wherein the sub-shielding layers include a lower layer and an upper layer on the lower layer, the upper layer having a density greater than that of the lower layer.

7. The backlight module as claimed in claim 1, wherein the light sources are respectively within the range of the orthographic projection profile of the light-shielding composite layers.

8. The backlight module as claimed in claim 1, wherein a distance between two adjacent light sources along a first direction is smaller than a distance between two adjacent light sources along a second direction.

9. The backlight module as claimed in claim 8, wherein the length direction of each of the light-shielding composite layers is the same as the first direction.

10. The backlight module as claimed in claim 8, wherein the width direction of each of the light-shielding composite layers is the same as the second direction.