TWI844001B - Backlight module - Google Patents

Abstract

A backlight module includes plural light sources, a diffuser, and plural light-shielding multilayers. The diffuser is located above the light sources. The light-shielding multilayers are located on the diffuser and respectively correspond to the light sources in position. A width of each of the light-shielding multilayers is gradually decreased from the diffuser toward a direction away from the light sources.

Description

Backlight module

The present disclosure relates to a backlight module.

In recent years, the types of light sources used in backlight modules have become increasingly diverse. For example, mini LEDs can be used in backlight modules for display devices. In order to prevent the area corresponding to the light source from being too bright, a diffusion plate can generally be placed above the light source to make the light uniform.

Although the ink pattern on the diffuser can block the light from the light source, due to the current screen printing technology, the ink used to form the diffuser pattern is mostly flat or concave in thickness, so the light passing through the ink pattern is not uniform, which can easily cause the light directly above the light source to be bright and the edges to be dark. When the backlight module is turned on, you may see defects caused by uneven brightness, such as LED mura.

A technical aspect of the present disclosure is a backlight module.

According to some embodiments of the present disclosure, a backlight module includes a plurality of light sources, a diffusion plate, and a plurality of light shielding composite layers. The diffusion plate is located above the light sources. The light shielding composite layers are located on the diffusion plate and correspond to the positions of the light sources respectively. The width of each light shielding composite layer gradually decreases from the diffusion plate to the direction away from the light source.

In some embodiments, each of the above-mentioned light-shielding composite layers includes a plurality of sub-light-shielding layers, and the width of the topmost layer of these sub-light-shielding layers is greater than the width of the corresponding light source.

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

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

In some implementations, the sub-light-shielding layers have different transmittances.

In some implementations, the sub-light-shielding layer includes a lower layer and an upper layer on the lower layer, and the density of the upper layer is greater than the density of the lower layer.

In some embodiments, the above-mentioned light sources are respectively within the orthographic projection outline range of the shading composite layer.

In some implementations, 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 implementations, the length direction of each of the above-mentioned light-shielding composite layers is the same as the first direction.

In some implementations, the width direction of each of the above-mentioned light-shielding composite layers is the same as the second direction.

In the above-mentioned embodiment of the present disclosure, since the backlight module has a shading composite layer located on the diffusion plate and corresponding to the position of the light source respectively, and the width of the shading composite layer gradually decreases from the diffusion plate toward the direction away from the light source, the central area of the shading composite layer is thicker and the edge area is thinner, so that the central area of the shading composite layer has a better shading effect. In this way, when the light source under 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 in the edge area of the shading composite layer, due to the change in the width of the shading composite layer, the central area of the shading composite layer can block more light and the edge area can block less light, achieving the effect of light uniformity, which can overcome the problem of defective screens (such as LED mura) caused by uneven brightness. In addition, the shading composite layer can be printed multiple times, which is convenient for production.

The embodiments disclosed below provide many different embodiments, or examples, for implementing the different features of the subject matter provided. Specific examples of components and arrangements are described below to simplify the present invention. Of course, these examples are only examples and are not intended to be limiting. In addition, the present invention may repeat component symbols and/or letters in each example. This repetition is for the purpose of simplicity and clarity, and does not itself specify the relationship between the various embodiments and/or configurations discussed.

Spatially relative terms such as "below," "beneath," "lower," "above," "upper," and the like may be used herein for descriptive purposes to describe the relationship of one element or feature to another element or feature as illustrated in the accompanying 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 accompanying figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

FIG. 1 shows a cross-sectional view of a backlight module 100 according to an embodiment of the present disclosure. FIG. 2 shows a three-dimensional view of a light-shielding composite layer 130 of FIG. Referring to FIG. 1 and FIG. 2 simultaneously, the backlight module 100 includes a plurality of light sources 110, a diffusion plate 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 a Mini LED. The diffusion plate 120 is located above the light source 110. The light-shielding composite layers 130 are located on the diffusion plate 120 and correspond to the positions of the light sources 110, respectively. As shown in FIG. 1, the number of light-shielding composite layers 130 is the same as that of the light sources 110 and they are aligned in the vertical direction. In the present embodiment, the backlight module 100 has six light-shielding composite layers 130 and six light sources 110, but this is not intended to limit the present disclosure. In addition, the width of each light-shielding composite layer 130 gradually decreases in a direction D from the diffusion plate 120 away from the light source 110. Such a design allows the thickness of the central area of the light-shielding composite layer 130 to be greater than the thickness of the edge area. In this article, the central area of the light-shielding composite layer 130 may refer to the area directly above the light source 110, and the edge area of the light-shielding composite layer 130 may refer to the area surrounding the central area of the light source 110 and not overlapping with the light source 110 in the vertical direction.

The light-shielding composite layer 130 can be formed by multiple screen printing processes, such as two screen printing processes, to form a structure as shown in FIG. 2. The material of the light-shielding composite layer 130 can 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 lower sub-light-shielding layer 132 is greater than the width W2 of the upper sub-light-shielding layer 134, so that the thickness of the central area of the light-shielding composite layer 130 is greater than the thickness of the edge area. For example, the sub-light-shielding layers 132 and 134 can have the same thickness H. In this way, the central area of the light-shielding composite layer 130 can have a thickness twice as large as H, which is the total thickness 2H of the sub-light-shielding layers 132 and 134, for example, 15 to 45 μm, and the edge area of the light-shielding composite layer 130 has a thickness H, which is the thickness H of the underlying sub-light-shielding layer 132.

Specifically, since the backlight module 100 has a shading composite layer 130 located on the diffusion plate 120 and corresponding to the positions of the light sources 110, and the width of the shading composite layer 130 gradually decreases from the diffusion plate 120 toward the direction D away from the light source 110, the central area of the shading composite layer 130 is thicker and the edge area is thinner, so that the central area of the shading composite layer 130 has a better shading effect. Thus, when the light source 110 below the light shielding composite layer 130 emits light, although the light source 110 irradiates more light in the central area of the light shielding composite layer 130 and less light in the edge area of the light shielding composite layer 130, the width of the light shielding composite layer 130 varies, so that the central area of the light shielding composite layer 130 can block more light and the edge area can block less light, thereby achieving the effect of light uniformity, and overcoming the problem of defective images (such as LED mura) caused by uneven brightness. The light shielding composite layer 130 can be printed multiple times, which is convenient for production.

In the present embodiment, the width W2 of the topmost layer of the sub-shading layer (i.e., the sub-shading layer 134) is greater than the width W3 of the corresponding light source 110. Such a design ensures that the light emitted from the light source 110 directly upward will not only pass through the sub-shading layer 132, but also pass through the sub-shading layer 134, so as to enhance the shading effect directly above the light source 110. Since the topmost sub-shading layer 134 with the smallest width W2 is wider than the light source 110, the other sub-shading layers 132 are of course also wider than the light source 110, so the light sources 110 of FIG. 1 can be respectively within the orthographic projection contour range A of the shading composite layer 130. The contour range A is the area between the two dotted 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 may be a rectangle or other types of polygons. In addition, the sub-light shielding layers 132 and 134 may have the same density and the same transmittance, such as a transmittance of 85% to 95%, but this does not limit the present disclosure. In other embodiments, the sub-light shielding layers may have different shapes, densities, and transmittances (as will be described in FIG. 4 ).

In addition, please refer to FIG. 1 , the backlight module 100 may further include a substrate 140, a packaging glue 150 and a glue body 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 packaging glue 150 covers the light source 110 to provide protection and insulation effects and prevent moisture from entering. The glue body 160 may be disposed on the inner surface of the housing to support the substrate 140 and provide a buffering effect.

It should be understood that the connection relationship, materials and functions of the components described above will not be repeated, and are described first. In the following description, other types of light-shielding composite layers will be described.

FIG. 3 shows a three-dimensional diagram of a light-shielding composite layer 130a according to another embodiment of the present disclosure. The light-shielding composite layer 130a can be formed by multiple screen printings, for example, four screen printings, to form a structure as shown in FIG. 3. The difference between this embodiment and the embodiment of FIG. 2 is that the light-shielding composite layer 130a includes four sub-light-shielding layers 132a, 134a, 136a, and 138a. Among them, the width of the sub-light-shielding layer 132a is greater than the width of the sub-light-shielding layer 134a, the width of the sub-light-shielding layer 134a is greater than the width of the sub-light-shielding layer 136a, and the width of the sub-light-shielding layer 136a is greater than the width of the sub-light-shielding layer 138a. That is to say, the width of the shading composite layer 130a gradually increases from the sub-shading layer 132a to the sub-shading layer 134a, the sub-shading layer 136a, and the sub-shading layer 138a, so that the thickness of the central area of the shading composite layer 130a is greater than the thickness of the edge area, thereby achieving the effect of light uniformity.

The light shielding composite layer 130a of FIG. 3 may be applied to the backlight module 100 of FIG. 1 , for example, it may replace the light shielding composite layer 130 of FIG. 1 and correspond to the position of the light source 110 .

FIG. 4 shows a top view of a light-shielding composite layer 130b according to another embodiment of the present disclosure. The light-shielding composite layer 130b can be formed by multiple screen printing processes, such as two screen printing processes, to form a structure as shown in FIG. 4. This embodiment differs 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 different transmittances. In this embodiment, the sub-light-shielding layer 132b is a lower layer, and the sub-light-shielding layer 134b is an upper layer on the lower layer, and the density of the upper layer is greater than the density of the lower layer. For example, the sub-light-shielding layer 132b is a circle formed by dot ink, and the sub-light-shielding layer 134b is an octagon (16-sided polygon) formed by surface ink. Therefore, the transmittance of the sub-light-shielding layer 134b is less than the transmittance of the sub-light-shielding layer 132b, which is helpful in blocking the light directly above the light source 110 (see Figure 1).

In addition, the width of the sub-light shielding layer 132b is greater than the width of the sub-light shielding layer 134b. Therefore, the thickness of the central area of the light shielding composite layer 130b is greater than the thickness of the edge area, achieving the effect of light uniformity. The light shielding composite layer 130b of FIG. 4 can be applied to the backlight module 100 of FIG. 1, for example, it can replace the light shielding composite layer 130 of FIG. 1 and correspond to the position of the light source 110.

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

FIG. 5 shows a top view of the light-shielding composite layer 130b of FIG. 4 after the lower layer (sub-light-shielding layer 132b) is formed and before the upper layer (sub-light-shielding layer 134b) is formed. Referring to FIG. 4 and FIG. 5 simultaneously, the diffusion plate 120 can first be formed into the sub-light-shielding layer 132b by screen printing ink in a dotted form. Then, the diffusion plate 120 can be formed into the sub-light-shielding layer 134b on the sub-light-shielding layer 132b by screen printing ink in another plane form. In this way, the light-shielding composite layer 130b of FIG. 4 can be obtained.

FIG. 6 shows a top view of a light-shielding composite layer 130c according to another embodiment of the present disclosure. The outer contour of the light-shielding composite layer 130c is shown in FIG. 6, and the number of stacked sub-light-shielding layers does not limit the present disclosure. The light-shielding composite layer 130c corresponds to the position of the light source 110, so that the light source 110 is covered by the light-shielding composite layer 130c. In the present embodiment, the distance d1 between two adjacent light sources 110 along the first direction D1 is smaller than the 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.

In this configuration, although the distance d1 between the two light sources 110 arranged along the first direction D1 is short, making the regional brightness brighter, the light shielding composite layer 130c extending along the first direction D1 is arranged above, so that excessive light can be effectively blocked, achieving the effect of light uniformity. In addition, the distance d2 between the two light sources 110 arranged along the second direction D2 is long, making the regional brightness darker, but because the light shielding composite layer 130c extending along the first direction D1 is arranged above, only a small amount of light is blocked in the second direction D2, 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, it can replace the light shielding composite layer 130 of FIG. 1 and correspond to the position of the light source 110.

The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand the aspects of the present disclosure. Those skilled in the art should understand that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to achieve the same purpose and/or achieve the same advantages as the embodiments described herein. Those skilled in the art should also recognize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions and modifications here without departing from the spirit and scope of the present disclosure.

100: backlight module 110: light source 120: diffusion plate 130,130a,130b,130c: shading composite layer 132,132a,132b: sub-shading layer 134,134a,134b: sub-shading layer 136a,138a: sub-shading layer 140: substrate 150: encapsulation glue 160: glue body A: outline range D: direction D1: first direction D2: second direction d1,d2: distance H: thickness W1,W2,W3: width

The disclosure is best understood from the following embodiments when read in conjunction with the accompanying illustrations. Note that various features are not drawn to scale, in accordance with standard practice in the industry. In fact, the dimensions of various features may be increased or decreased arbitrarily for clarity of discussion. FIG. 1 illustrates a cross-sectional view of a backlight module according to an embodiment of the disclosure. FIG. 2 illustrates a three-dimensional view of the light-shielding composite layer of FIG. 1. FIG. 3 illustrates a three-dimensional view of the light-shielding composite layer of another embodiment of the disclosure. FIG. 4 illustrates a top view of the light-shielding composite layer of yet another embodiment of the disclosure. FIG. 5 illustrates a top view of the light-shielding composite layer of FIG. 4 after the lower layer is formed and before the upper layer is formed. Figure 6 shows a top view of a light-shielding composite layer according to another embodiment of the present disclosure.

Domestic storage information (please note in the order of storage institution, date, and number) None Foreign storage information (please note in the order of storage country, institution, date, and number) None

100: Backlight module

110: Light source

120:Diffusion plate

130: Shading composite layer

140: Substrate

150: Packaging glue

160:Colloid

A: Outline range

D: Direction

W2,W3: Width

Claims (9)

A backlight module includes: a plurality of light sources; a diffusion plate located above the light sources; and a plurality of light-shielding composite layers located on the diffusion plate and corresponding to the positions of the light sources, wherein the width of each of the light-shielding composite layers gradually decreases from the diffusion plate toward the direction away from the light sources, wherein each of the light-shielding composite layers includes a plurality of sub-light-shielding layers, and the width of the topmost layer of the sub-light-shielding layers is greater than the width of the corresponding light source. A backlight module as described in claim 1, wherein the sub-light shielding layers have different shapes. A backlight module as described in claim 1, wherein the sub-light shielding layers have the same thickness. A backlight module as described in claim 1, wherein the sub-light shielding layers have different transmittances. The backlight module as described in claim 1, wherein the sub-light shielding layers include a lower layer and an upper layer on the lower layer, and the density of the upper layer is greater than the density of the lower layer. A backlight module as described in claim 1, wherein the light sources are respectively within the orthographic projection contour range of the light-shielding composite layers. A backlight module as described in claim 1, wherein the distance between two adjacent light sources along a first direction is smaller than the distance between two adjacent light sources along a second direction. As described in claim 7, the length direction of each of the light-shielding composite layers is the same as the first direction. A backlight module as described in claim 7, wherein the width direction of each of the light-shielding composite layers is the same as the second direction.

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