JP7301134B2 - Light control film, backlight module and display device - Google Patents

Description

1. Field of the Invention The present invention relates to a light control assembly, and more particularly to a light control film adapted to direct type backlight modules and display devices and its application.

In conventional display devices, a backlight module is mainly used to provide backlight for the display panel. The backlight module of the current display device can be classified into a direct type and an edge light type according to its light input method. Among them, the direct type backlight module provides the necessary backlight for the display panel by arranging a light source in a housing and combining optical films such as a prism sheet and a diffusion sheet.

The following methods can be used to select the light source for the direct type backlight module. Using red, green and blue monochromatic light emitting diodes (RGB LEDs) as light sources, light rays are diffused, reflected or refracted as they pass through the optical film to complete light mixing to obtain white light. Alternatively, a blue light emitting diode is used as the light source, and the blue light emitted from the blue light emitting diode excites the quantum dot thin film to emit white light. However, since the number of light reflections and refractions is small near the periphery of the backlight module, uneven light mixing occurs, and as a result, color differences may occur in the light near the periphery of the backlight module. .

Therefore, how to avoid the problem of color difference caused by non-uniform light mixture at the periphery of the backlight module is an urgent issue for current manufacturers.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a light control film, a backlight module, and a display device that improve the color difference problem caused by non-uniform light mixing at the edge of the current backlight module.

In order to solve the above object, a light control film according to the present invention is arranged between a color conversion layer and a display panel of a direct type backlight module, and the light control film comprises:
a substrate defining a central region and a peripheral region;
At least one light control layer containing a colorant,
The light management layer is disposed on the substrate, and the colorant content in the light management layer tapers off along the direction from the peripheral region to the central region.
Wherein, the light control film includes two light control layers, and the two light control layers are respectively disposed on two opposite sides of the substrate.
Wherein, the thickness of the light control layer gradually decreases along the direction from the outer edge of the peripheral area to the central area.
wherein the substrate is divided into a first direction and a second direction perpendicular to the first direction; the light control layer is distributed with a plurality of parallel rib-like structures; The shaped structures are elongated along the first direction and arranged along the second direction.
Wherein, the spacing between two adjacent rib-like structures is gradually increased along the direction from opposite sides of the light control layer to the center of the central region.
Wherein, the thickness of each said rib-like structure is tapered along the direction from its opposite sides to the center.
Wherein, each said rib-like structure has a rib-like central region, and said rib-like central region is planar.
Therein, each rib-like structure is an inverted V-shaped structure having an upper edge provided with a fillet.
Among them, the light control layer has a plurality of fine structures formed in the peripheral region, and the distribution density of the plurality of fine structures gradually decreases along the direction from the outer edge of the peripheral region to the center of the central region. It is
Of which, the sizes of two adjacent microstructures taper along the direction from the outer edge of the peripheral region to the center of the central region.
Wherein, the spacing between two adjacent microstructures increases gradually along the direction from the outer edge of the peripheral region to the center of the central region.
Wherein, the light control layer is formed on the substrate with a gel containing a colorant, or the light control layer is formed on the substrate by pigment printing.

In order to achieve the above object, the backlight module according to the present invention includes:
a housing;
a light source disposed within the housing;
a color conversion layer disposed within the housing and positioned in front of the light source;
and the aforementioned light control film arranged on the front side of the color conversion layer,
The colorant of the light control film is a color that corrects the color difference of light emitted from the backlight module.
Wherein, the backlight module comprises at least one optical film, and the optical film is disposed in front of the light management film.

In order to achieve the above object, the backlight module according to the present invention includes:
the aforementioned backlight module;
a display panel disposed in front of the backlight module.

In the light control film of the present invention, a light control layer containing a colorant is mainly arranged on the substrate, and the content of the colorant in the light control layer is adjusted by utilizing the structural change of the light control layer. By gradually decreasing from the peripheral region toward the central region, when the light emitted from the light source passes through the light control layer of the light control film, the colorant in the light control layer is used for light control. The effect can be achieved, the uniformity of light mixing at the edge of the backlight module can be improved, and the overall optical sense of the backlight module can be improved.

1 is a schematic side view of a first preferred embodiment of a light management film of the present invention; FIG. Fig. 2 is a schematic side view of a second preferred embodiment of the light management film of the present invention; FIG. 11 is a schematic external perspective view of a third preferred embodiment of the light control film of the present invention; FIG. 4 is a schematic cross-sectional view along AA of FIG. 3; FIG. 11 is a schematic external perspective view of forming a plane on the rib-like structure of the third preferred embodiment of the light control film of the present invention; FIG. 4 is a schematic side view of the fourth preferred embodiment of the light management film of the present invention with hemispherical microstructures; FIG. 4 is a schematic side view of the fourth preferred embodiment of the light management film of the present invention with pyramidal microstructures; FIG. 5 is a schematic diagram of a fifth preferred embodiment of the light management film of the present invention; 1 is a schematic side sectional view of a backlight module of the present invention; FIG. 1 is a schematic side sectional view of a display device of the present invention; FIG.

1 to 10, which are some preferred embodiments of the light control film 10 of the present invention, disposed between the color conversion layer 23 of the direct backlight module 20 and the display panel 31, The light management film 10 comprises a substrate 11 and at least one light management layer 12a-12e containing a colorant, the substrate 11 defining a central region 13 and a peripheral region 14, wherein the A central region 13 is surrounded by said peripheral region 14 . For example, the light modulating layers 12a to 12d containing the colorant are formed by applying a gel containing the colorant (for example, UV gel) onto the substrate 11, and then using an appropriate mold. The light layers 12a to 12d may be molded on the substrate 11. Alternatively, as shown in FIG. ) printed on the substrate 11 may be selected.

Wherein, the substrate 11 has two opposing sides, and the light control layers 12a-12e may be selectively disposed on at least one side of the substrate 11, or may be disposed on two opposing sides. and the light modulating layers 12a to 12e may be arranged on both of them.

Among them, the colorant content of the light control layers 12a to 12e gradually decreases from the peripheral region 14 toward the central region 13. As shown in FIG. More specifically, the density of the colorant in the light-modulating layers 12a-12e is homogeneous, and the means for adjusting the amount of colorant in the embodiments described later is the thickness of the light-modulating layers 12a-12e. This can be done by changing the interval of the rib structure, the size of the microstructures 17a and 17b, the arrangement density of the microstructures 17a and 17b, and the like. The colorant amount per unit area gradually decreases from the peripheral region 14 toward the central region 13 depending on the position of the unit area near the peripheral region 14 or the central region 13 .

The colorants of the dimming layers 12a to 12e are colors for correcting the color difference of light rays emitted by the color conversion layer 23 of the backlight module. For example, if the ray color is biased toward blue, the colorant's selective corrective color is yellow. In the first to fourth preferred embodiments of the light control film 10 of the present invention, the colorant content of the light control layers 12a to 12d varies depending on structural changes such as thickness and spacing of the light control layers 12a to 12d. is gradually decreased from the peripheral region 14 toward the central region 13, and this method involves applying a gel (eg, UV gel) mainly containing a colorant to the substrate, and then applying the light control layers 12a to 12d. is molded on the substrate 11 with an appropriate mold. Since the curing speed of the UV gel is fast, drying time can be saved, and production efficiency can be improved. Each embodiment will be described below.

As shown in FIG. 1, in the first preferred embodiment of the light management film 10 of the present invention, the thickness of the light management layer 12a gradually decreases along the direction from the outer edge of the peripheral region 14 to the central region 13. However, in the first preferred embodiment of the light management film 10, mainly due to the thickness variation of the light management layer 12a, the colorant content that the light rays come into contact with when passing through the peripheral region 14 is increased. Thus, there is an effect of finely adjusting the dimming of the central area 13 and the peripheral area 14 .

As shown in FIG. 2, in the second preferred embodiment of the light management film 10 of the present invention, the thickness of the light management layer 12b gradually decreases along the direction from the outer edge of the peripheral region 14 to the central region 13. However, the central region 13 may be a flat surface, the central region 13 has a uniformly distributed colorant content, and the second preferred embodiment of the light management film 10 mainly consists of the By varying the thickness of the light management layer 12b to increase the colorant content that light rays contact when passing through said peripheral region 14, a second preferred embodiment of the present invention provides for said central region 13: It has the effect of improving the dimming of the peripheral area 14 .

As shown in FIG. 3, in the third preferred embodiment of the light management film 10 of the present invention, the substrate 10 has a first direction D1 and a second direction D2 perpendicular to the first direction D1. and a plurality of parallel rib-like structures 15 are distributed on the light control layer 12c, the rib-like structures 15 extending along a first direction D1 and extending in a second are arranged along the direction D2.

As shown in FIG. 4, the thickness of opposite sides of said rib-like structure 15 tapers along the direction from the outer edge of peripheral region 14 to the center of central region 13 . Also, as shown in FIG. 3, the spacing between two adjacent rib-like structures 15 is gradually increased along the direction toward the center of the substrate 11 from both sides of the substrate 11 facing each other in the second direction D2. In the third preferred embodiment of the light control film 10, mainly by changing the thickness of the rib-like structure 15 itself on the light control layer 12c and the interval between the adjacent rib-like structures 15, The colorant content of the central region 13 and the peripheral region 14 can be further fine-tuned, and the dimming effect of the central region 13 and the peripheral region 14 can be further fine-tuned.

Also, without compromising optical sense, each rib-like structure 15 has a central rib-like region 151, which is planar 152, as shown in FIG. Alternatively, each rib-like structure 15 may be an inverted V-shaped structure, the upper edge of which is filleted, and the design of this flat surface 152 or fillet upper edge allows the rib-like structure 15 to It is possible to prevent damage to other films.

As shown in FIGS. 6 and 7, in the fourth preferred embodiment of the light control film 10 of the present invention, the light control layer 12d has a plurality of fine structures 17a and 17b formed in the peripheral region 14. For example, the microstructures 17a, 17b may be hemispherical or pyramidal. The distribution density of the plurality of microstructures 17a, 17b tapers along the direction from the outer edge of the peripheral region 14 to the center of the central region 13, and in this embodiment two adjacent microstructures 17a, 17b The spacing of 17b is gradually increased along the direction from the outer edge of the peripheral region 14 to the center of the central region 13, and the size variation of each microstructure 17 and the spacing variation of adjacent microstructures 17 cause the central region The difference in colorant content between 13 and the peripheral region 14 can be further fine-tuned, and the dimming effect between the central region 13 and the peripheral region 14 can be further fine-tuned, and the central region The difference in color difference between 13 and the peripheral area 14 can be reduced. Also, in another embodiment, instead of varying the spacing, the sizes of two adjacent microstructures 17a, 17b are gradually reduced along the direction from the outer edge of the peripheral region 14 to the center of the central region 13. Likewise, the difference in colorant content between the central region 13 and the peripheral region 14 can be further fine-tuned, and further the dimming effect between the central region 13 and the peripheral region 14 can be fine-tuned. and the difference in color difference between the central region 13 and the peripheral region 14 can be reduced.

As shown in FIG. 8, in the fifth preferred embodiment of the light control film 10 of the present invention, the light control layer 12e is formed by printing colorants on the bottom surface of the optical film 24 in a gradation manner by color printing. , Here, the colorant content of the light control layer 12e is gradually reduced from the periphery of the light control film 10 toward the inside, and the colorant is not printed in the central region 13 of the light control layer 12e. . More specifically, the light modulating layer of this embodiment can use a screen printing method, and by planning the mesh arrangement density and mesh size, the color per unit area can be adjusted. The amount of colorant can be gradually decreased from the peripheral region to the central region, and in this way, even if there is no change in the thickness of the light-modulating layer, the gradation distribution of the printed dots of the colorants of the same density and the size of the printed dots can be changed. The change can improve the color difference due to the non-uniformity of light mixing in the periphery and improve the optical sense of the whole backlight module. This method, which is mainly performed by screen printing, has the advantages of not only low cost, but also aging of revision and short manufacturing process time.

Also referring to FIG. 9, one preferred embodiment of the backlight module 20 of the present invention comprises a housing 21, a light source 22, a color conversion layer 23, and the light control film 10 as described above.

The light source 22 is arranged inside the housing 21 . For example, the light source 22 may be selected from blue light emitting diodes, preferably arranged in an array within the housing 21 .

The color conversion layer 23 is disposed in the housing 21 and positioned in front of the light source 22, the color conversion layer 23 has two opposite surfaces, and one surface facing the light source 22 receives light. surface, and the other surface is the light emitting surface. The color conversion layer 23 is used to convert the light of the light source 22 into desired color light, for example, blue light emitting diode is selected as the light source 22, and the color conversion layer 23 is selected quantum dot film. can be excited by blue light to emit white light.

The light control film 10 is disposed on the front side of the color conversion layer 23, the light control film 10 is disposed on the light emitting surface of the color conversion layer 23, and the colorant of the light control film 10 is , are correction colors for the color difference of light emitted from the light emitting surface of the color conversion layer 12 of the backlight module 20 . For example, as described above, a blue light emitting diode is selected as the light source 22, and after the light is converted into desired color light through the color conversion layer 23, the color difference between the central region 13 and the peripheral region 14 is different. , and the above-mentioned color difference difference is generally due to the lack of light mixing effect, so that the desired color light remains biased towards blue light. The colorant should be selected to correct the biased light color, yellow colorant in this example, to fine-tune the color difference to achieve good light mixing uniformity, and the overall backlight module Optical sense can be improved.

Further, the backlight module 20 comprises at least one optical film 24, the optical film 24 is disposed in front of the light control film 10, and the optical film 24 comprises a prism sheet, a diffusion sheet, etc. Also, the number and arrangement order can be determined according to need. More preferably, the bottom surface of the optical film 24 includes the above-described light control film 10, that is, the substrate 11 is an optical film having excellent light transmittance, such as a prism sheet or a brightness enhancement film. Alternatively, light modulating layers 12a to 12e are disposed on the bottom surface of the optical film, and referring to FIGS. UV gel) is coated on it and molded with an appropriate mold, or referring to FIG. , printed on the bottom surface of the optical film 24 may be selected. For example, when the light source 22 is a blue light-emitting diode, yellow is selected as the colorant, and the density at which the yellow pigment is printed decreases gradually from the peripheral region 14 toward the central region 13 .

Also, referring to FIG. 10, one preferred embodiment of the display device 30 of the present invention comprises the aforementioned backlight module 20 and a display panel 31 arranged in front of the backlight module 20. there is

As described above, the light control film 10 of the present invention mainly disposes the light control layers 12a to 12e containing colorants on the substrate 11, and the thickness of the light control layers 12a to 12e or The colorant content of the light control layers 12a to 12e is gradually decreased from the peripheral region 14 to the central region 13 by using the structural change of the interval or by using the gradation printing method, so that the peripheral region 14 and the When the light from the light source 22 passes through the light control layers 12a to 12e of the light control film 10, the colorant in the light control layers 12a to 12e is changed due to the difference in the unit colorant content from the central region 13. It can be used to obtain a dimming effect, and furthermore, it can improve the uniformity of light mixing at the edge of the backlight module 20 and improve the optical sense of the whole backlight module 20 .

REFERENCE SIGNS LIST 10 light control film 11 substrate 12a to 12e light control layer 13 center region 14 peripheral region 15 rib structure 17a, 17b fine structure 20 backlight module 21 housing 22 light source 23 color conversion layer 24 optical film 30 display device 31 display panel D1 th 1 direction D2 2nd direction.

Claims (9)

A light control film disposed between a color conversion layer and a display panel of a direct type backlight module,
a substrate defining a central region and a peripheral region;
at least one light control layer containing a colorant;
with
The light control layer is disposed on the substrate, the colorant content in the light control layer gradually decreases along the direction from the peripheral region to the central region, and the color of the light control film is The color is a correction color for the color difference of the light emitted from the color conversion layer of the backlight module.
A light control film characterized by: The thickness of the light modulating layer gradually decreases along the direction from the outer edge of the peripheral region to the center of the central region.
The light control film according to claim 1, characterized in that: The substrate is divided into a first direction and a second direction perpendicular to the first direction, a plurality of parallel rib-like structures are distributed on the light control layer, and the plurality of rib-like structures are distributed. is stretched along the first direction and arranged along the second direction,
The light control film according to claim 1, characterized in that: each said rib-like structure having a central rib-like region, said central rib-like region being planar;
The light control film according to claim 3, characterized in that: The light modulating layer has a plurality of microstructures formed in the peripheral region, and the distribution density of the plurality of microstructures is gradually reduced along the direction from the outer edge of the peripheral region to the center of the central region. there is
The light control film according to claim 1, characterized in that: wherein the light control layer is formed on the substrate with a gel containing a colorant;
The light control film according to claim 1, characterized in that: The light control layer is formed on the substrate by a gradation color printing method,
The light control film according to claim 1, characterized in that: a housing;
a light source disposed within the housing;
a color conversion layer disposed within the housing and positioned in front of the light source;
The light control film according to any one of claims 1 to 7, which is arranged on the front side of the color conversion layer;
with
The colorant of the light control film is a color that corrects the color difference of the light emitted from the backlight module,
The backlight module comprises at least one optical film, and the optical film is disposed in front of the light management film.
A backlight module characterized by: a backlight module according to claim 8;
a display panel disposed in front of the backlight module;
A display device comprising:

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