KR20240123339A - Optical films, optical film groups, backlight modules and display devices - Google Patents

Abstract

The present disclosure relates to an optical film (100), an optical film group (600), a backlight module (200), and a display device (900). The optical film (100) includes a body (110), a plurality of first prism structures (120), and a plurality of second prism structures (130). The body (110) has a first optical surface (111) and a second optical surface (112) which face each other. The first prism structures (120) are arranged on the first optical surface (111). Each of the first prism structures (120) has a first extension direction (D1). The second prism structures (130) are arranged on the second optical surface (112). Each of the second prism structures (130) has a second extension direction (D2). The first extension direction (D1) is different from the second extension direction (D2).

Description

Optical films, optical film groups, backlight modules and display devices

The present disclosure relates to optical films and applications thereof, and more particularly, to optical films capable of generating a large light emission angle, optical film groups, and backlight modules and display devices using the optical films and optical film groups.

In the EU, vehicle displays have a viewing angle standard (Deutsches Flachdisplay Forum) that takes into account the viewing angles of the driver and passenger seats, so the current vehicle product standards are designed with reference to this standard.

The prism sheets currently used in backlight modules mainly focus the light along the frontal viewing direction. However, vehicle displays are installed below the line of sight, and the Center Informative Display (CID) needs to be designed to be visible from both the driver's seat and the passenger's seat. Therefore, the viewing angle standard is an upward-facing shape (upper viewing angle within 20 degrees, lower viewing angle within 15 degrees), and the left and right viewing angles are distributed more widely (left and right viewing angles within 50 degrees), which is much different from the viewing angle required by general tablets or laptops.

In general, the viewing angle can be reduced by using a privacy screen, but the energy loss of the privacy screen is significant. If the brightness of the desired large viewing angle can be reached only by increasing the overall brightness, there is a problem of power consumption. Therefore, the motivation of the present application is to develop an optical film that can achieve the purpose of power saving as well as meet a specific viewing angle and brightness when applied to a display.

Accordingly, one object of the present disclosure is to provide an optical film and a group of optical films that can be applied to a backlight module and a display device to suit a specific viewing angle.

In accordance with the above-described purpose of the present disclosure, an optical film is proposed. The optical film includes a body, a plurality of first prism structures, and a plurality of second prism structures. The body has a first optical surface and a second optical surface which are opposite to each other. The first prism structures are arranged on the first optical surface, wherein each of the first prism structures has a first extension direction. The second prism structures are arranged on the second optical surface, wherein each of the second prism structures has a second extension direction. Here, the first extension direction is different from the second extension direction.

According to one embodiment of the present disclosure, the first prism structure described above has an array density (Y), each of the first prism structures has a first side surface and a second side surface connected to each other, and an included angle (X) is formed between the first side surface and the second side surface, and the array density (Y) and the included angle (X) satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ .

According to one embodiment of the present disclosure, there is a gap between the first prism structures described above, and the array density (Y) is calculated based on the function Y=（P ₁ -W ₁ ）/P ₁ , where P ₁ is the gap between any two adjacent first prism structures, and W ₁ is the width of each gap.

According to one embodiment of the present disclosure, each of the first prism structures described above is a strip structure that is recessed or protruded from the first optical surface.

According to one embodiment of the present disclosure, the included angle between the first extension direction and the second extension direction described above is 90 degrees.

According to one embodiment of the present disclosure, when light is incident on a body from one of the first optical surface and the second optical surface and is emitted from the other of the first optical surface and the second optical surface, a portion of the light is emitted in a frontal viewing direction, and another portion of the light is emitted in a side viewing direction. Here, a ratio of the amount of light emitted in the side viewing direction to the amount of light emitted in the frontal viewing direction is greater than 0.4, and includes an endpoint value.

According to one embodiment of the present disclosure, the frontal viewing direction described above is parallel to the normal to the exit light of the optical film, and the included angle between the side viewing direction and the normal to the exit light is greater than 40 degrees, including the endpoint values.

In accordance with the above-described purpose of the present disclosure, a backlight module is also proposed. The backlight module comprises a light guide plate, a light source, the above-described optical film, and a film group. The light guide plate has a light-incident surface and a light-emission surface. The light source is arranged adjacent to the light-incident surface. The optical film is arranged in front of the light-emission surface. The film group is located between the optical film and the light guide plate.

In accordance with the above-described purpose of the present disclosure, a backlight module is proposed. The backlight module includes a light source and the above-described optical film. The light source includes a substrate and a plurality of light-emitting units arranged on the substrate. The optical film is arranged in front of the light source.

In accordance with the above-described purpose of the present disclosure, a display device is proposed. The display device includes the above-described backlight module and a display panel. The display panel is arranged in front of the backlight module.

In accordance with the above-described object of the present invention, an optical film group is proposed. The optical film group includes a first film and a second film. The first film has a first optical surface and a plurality of first prism structures arranged on the first optical surface, and each of the first prism structures has a first extension direction. The second film has a second optical surface and a plurality of second prism structures arranged on the second optical surface, and each of the second prism structures has a second extension direction, wherein the first optical surface and the second optical surface face opposite directions. Here, the first extension direction is different from the second extension direction.

According to one embodiment of the present disclosure, the first prism structure described above has an array density (Y), and each of the first prism structures has a first side surface and a second side surface connected to each other, and an included angle (X) is formed between the first side surface and the second side surface, wherein the array density (Y) and the included angle (X) satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ .

According to one embodiment of the present disclosure, there is a gap between any two adjacent first prism structures described above, and the array density (Y) is calculated by the function Y = (P ₁ -W ₁ )/P ₁ , where P ₁ is the gap between any two adjacent first prism structures, and W ₁ is the width of each gap.

According to one embodiment of the present disclosure, each of the first prism structures described above is a strip structure that is recessed or protruded from the first optical surface.

According to one embodiment of the present disclosure, the included angle between the first extension direction and the second extension direction described above is 90 degrees.

According to one embodiment of the present disclosure, when a light beam is incident on one of the first optical surface and the second optical surface and is emitted from the other of the first optical surface and the second optical surface, a portion of the light beam is emitted in a frontal viewing direction, and another portion of the light beam is emitted in a side viewing direction, wherein a ratio of the amount of light emitted in the side viewing direction to the amount of light emitted in the frontal viewing direction is greater than 0.4, including an endpoint value.

According to one embodiment of the present disclosure, the frontal viewing direction is parallel to the normal to the exit light of the optical film group, and the included angle between the side viewing direction and the normal to the exit light is greater than 40 degrees, including the endpoint values.

According to the above-described purpose of the present disclosure, a backlight module is also proposed. The backlight module includes a light guide plate, a light source, the above-described optical film group and a film group. The light guide plate has a light-incident surface and a light-emission surface. The light source is arranged adjacent to the light-incident surface. The optical film group is arranged in front of the light-emission surface. The film group is located between the optical film and the light guide plate.

In accordance with the above-described purpose of the present disclosure, a backlight module is proposed. The backlight module includes a light source and the above-described optical film group. The light source includes a substrate and a plurality of light-emitting units arranged on the substrate. The optical film is arranged in front of the light source.

In accordance with the above-described purpose of the present disclosure, a display device is proposed. The display device includes the above-described backlight module and a display panel. The display panel is arranged in front of the backlight module.

According to one embodiment of the present disclosure, there is a gap between any two adjacent first prism structures described above, and the array density (Y) is calculated by the function Y = (P ₁ -W ₁ )/P ₁ , where P ₁ is the gap between any two adjacent first prism structures, and W ₁ is the width of each gap.

As described above, the present disclosure can improve the overall viewing range by diverting a portion of direct light toward a different viewing angle direction mainly through the first prism structure and the second prism structure on the optical film or optical film group, so that it can be matched with a specific viewing angle without having to increase the current to improve the overall brightness.

To more fully understand the embodiment and its advantages, the following description is made with reference to the attached drawings.
FIG. 1 is a schematic diagram showing application of an optical film according to one embodiment of the present disclosure to a direct backlight module.
FIG. 2 is a partial schematic diagram showing an optical film according to one embodiment of the present disclosure.
Figure 3 is a schematic diagram showing the viewing angle standards for vehicle displays defined in the conventional EU.
FIG. 4 is a graph showing the relationship between the angle (X) and the array density (Y) of the first prism structure according to one embodiment of the present disclosure.
FIG. 5 is a schematic diagram showing the ratio of the side-view light emission to the front-view light emission generated using optical films having first prism structures having different angles and different array densities according to one embodiment of the present disclosure.
Figure 6a is a schematic diagram simulating the light emission brightness at each viewing angle of a conventional optical film.
FIG. 6b is a schematic diagram simulating the light emission brightness at each viewing angle of the optical film of the first prism structure according to one embodiment of the present disclosure.
FIG. 7 is a graph showing the relationship between the viewing angle and brightness simulated using an optical film according to one embodiment of the present disclosure and an optical film of a comparative example, respectively.
FIG. 8 is a schematic diagram showing application of an optical film according to one embodiment of the present disclosure to a direct backlight module.
FIG. 9 is a schematic diagram showing application of an optical film according to one embodiment of the present disclosure to an edge entry backlight module.
FIG. 10 is a schematic diagram showing a display device according to one embodiment of the present disclosure.
FIG. 11 is a schematic diagram showing application of an optical film group according to one embodiment of the present disclosure to a direct backlight module.
FIG. 12 is a partial schematic diagram showing an optical film group according to one embodiment of the present disclosure.
FIG. 13 is a schematic diagram showing the application of an optical film group according to one embodiment of the present disclosure to an edge entry backlight module.
FIG. 14 is a schematic diagram showing a display device according to another embodiment of the present disclosure.

Referring to FIG. 1, this is a schematic diagram showing the application of an optical film according to one embodiment of the present disclosure to a direct backlight module. The optical film (100) of the present embodiment is mainly applied to the direct backlight module (200, 500) illustrated in FIG. 1 and FIG. 8 or the edge-entry backlight module (300) illustrated in FIG. 9 in order to increase the light emission viewing angle of the backlight module (200, 300). In the backlight module (200) illustrated in FIG. 1, the optical film (100) is arranged in front of the light source (210). Here, the light source (210) includes a substrate (211) and a plurality of light-emitting units (212) arranged on the substrate (211). Accordingly, light provided from the light source (210) can directly pass through the optical film (100) and be emitted from the optical film (100).

As illustrated in FIG. 1, the optical film (100) of the present embodiment includes a body (110), a plurality of first prism structures (120), and a plurality of second prism structures (130). Here, the body (110) has a first optical surface (111) and a second optical surface (112), the first prism structure (120) is disposed on the first optical surface (111), and the second prism structure (130) is disposed on the second optical surface (112). As illustrated in FIG. 1, the first prism structure (120) has a first extension direction (D1), the second prism structure (130) has a second extension direction (D2), and the first extension direction (D1) is different from the second extension direction (D2). Accordingly, when light is incident on the optical film (100) from the first optical surface (111), the first prism structure (120) can convert a portion of the direct light into light in a different direction, and further emit the converted light through the second prism structure (130) on the second optical surface (112). Specifically, as illustrated in FIG. 1, under the action of the optical film (100), a portion of the light (e.g., light ray L1) can be emitted in the front-viewing direction through the gap (S1) between the first prism structures (120), and a portion of the light (e.g., light ray L2) can be emitted in the side-viewing direction under the action of the first prism structure (120). Here, the front-viewing direction means a direction in which the light is parallel to the normal direction of the optical film (100), and an included angle (θ) is formed between the side-viewing direction and the front-viewing direction. More specifically, the frontal viewing direction is parallel to the normal line of the light emitted from the optical film (100), and the included angle (θ) between the side viewing direction and the normal line of the light emitted is greater than 40 degrees and includes the end point value. In this way, the optical film (100) of the present embodiment can further divert a portion of the direct light to another viewing angle direction, thereby adjusting the size of the horizontal viewing angle to expand the viewing angle, so that the purpose of power saving can be achieved while matching a specific viewing angle and brightness without having to increase the current to improve the overall brightness.

In the present embodiment, each of the first prism structures (120) is a strip structure protruding from the first optical surface (111). In another embodiment, the first prism structure (120) may be a strip structure recessed from the first optical surface (111). In some embodiments, the included angle of the first extension direction (D1) and the second extension direction (D2) is 90 degrees. In addition, referring to FIG. 2, FIG. 2 is a partial schematic diagram showing an optical film according to one embodiment of the present disclosure. In one embodiment, each of the first prism structures (120) has a first side surface (121) and a second side surface (122) that are connected to each other, and an included angle (X) is formed between the first side surface (121) and the second side surface (122). The first prism structure (120) has an array density, a gap (P ₁ ) is provided between any two adjacent first prism structures (120), and a blank space (S1) has a width (W ₁ ). Here, the array density is calculated based on a function represented by Y = (P ₁ -W ₁ )/P ₁ .

In the present embodiment, when the ratio of the amount of light emitted in the side view direction (L2) to the amount of light emitted in the front view direction (L1) under the action of the optical film (100) is 0.4 or more, that is, when the ratio of the amount of light emitted in the side view direction to the amount of light emitted in the front view direction of the optical film (100) is 40% or more, the design of the first prism structure (120) must satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ .

Referring to FIG. 3 and Table 1, FIG. 3 is a schematic diagram showing the viewing angle standards of a conventional vehicle display defined in the EU. In the viewing angle standards of a vehicle display defined in the EU (Deutsches Flachdisplay Forum), in order to simultaneously consider the viewing angles of the driver's seat and the passenger's seat (e.g., the A+ area, the A area, and the B area shown in FIG. 3), the ratio of the amount of light emitted in the side viewing direction (i.e., the luminance of the B area) to the amount of light emitted in the frontal viewing direction of the vehicle display (i.e., the luminance of the A+ area) is specified to be greater than 37.5%. However, since this embodiment adopts a higher standard than the viewing angle standard for a vehicle display defined in the EU, requiring a ratio of the amount of light emitted in a side-viewing direction to the amount of light emitted in a front-viewing direction to be 40% or more (i.e., greater than 37.5%), if the optical film (100) is designed using the relationship of this embodiment, the light emission viewing angle can be expanded and the regulations on vehicle display brightness defined in the EU can be satisfied.

Table 1: Field of view ranges for each area in Figure 3 and EU field of view standards area Field of view range (horizontal, vertical) [degrees] EU's viewing angle standard [Candlelight/M ² ] A+ (-10, 8)(10, 8)
(10, -4)
(10, 4) >800(100%) A (-40, 20)(40, 20)
(40, -10)
(-40, -10) >450(56.3%) B (-50, 20)(50, 20)
(50, -10)
(-50, -10) >300(37.5%)

Also, referring to FIGS. 4 and 5, FIG. 4 is a graph showing the relationship between the narrow angle (X) and the array density (Y) of the first prism structure according to one embodiment of the present disclosure, and FIG. 5 is a schematic diagram showing the ratio of the side-view light output to the front-view light output generated using optical films of the first prism structures having different angles and different array densities according to one embodiment of the present disclosure, respectively. As can be seen in FIGS. 4 and 5, when the ratio of the side-view light emission amount to the front-view light emission amount of the optical film (100) is 40%, the narrow angle (X) of the first prism structure (120) can be set to 40 degrees and the array density to 54%, or the narrow angle (X) of the first prism structure (120) to 60 degrees and the array density to 43%, or the narrow angle (X) of the first prism structure (120) to 90 degrees and the array density to 33%, or the narrow angle (X) of the first prism structure (120) to 120 degrees and the array density to 59% to generate a specific light emission viewing angle. In addition, referring to FIGS. 6A and 6B, FIG. 6A is a schematic diagram simulating the light emission brightness of each viewing angle of a conventional optical film, and FIG. 6B is a schematic diagram simulating the light emission brightness of the first prism structure according to one embodiment of the present disclosure. This is a schematic diagram simulating the light emission brightness of each viewing angle of the film. Compared to the schematic diagram simulating the brightness of the conventional optical film of Fig. 6a, it can be clearly seen that the dark color region of the embodiment of Fig. 6b is separated into two regions, thereby reducing the light emission brightness of the frontal viewing angle, thereby reducing the consumption of light emission energy of the frontal viewing angle, and improving the side viewing angle brightness of the driver's seat and the passenger's seat. In the comparative example of a general prism sheet or a film sheet that does not satisfy the relational formula, the dark color region cannot be separated into two regions, and thus the purpose of the present application cannot be achieved.

It should be noted that the present disclosure is not limited to the above-described angle and array density, and that the included angle (X) and array density of the first prism structure (120) corresponding to the requirement of the ratio of light output can be calculated using the relationship of the present disclosure. For example, the graph of FIG. 4 is a graph showing the relationship between the included angle (X) and the array density of the first prism structure (120) when the ratio of the side-view light output to the front-view light output of the optical film (100) is 40%. The range above this graph shows the relationship between the included angle (X) and the array density of the first prism structure (120) corresponding to a higher ratio of the side-view light output to the front-view light output. For example, when the included angle (X) is 90 degrees, when the included angle (X) of the first prism structure (120) is 90 degrees, the array density is 33%, and at this time, the ratio of the side-view light output to the front-view light output is 40%. If a higher ratio of the side-view light output to the front-view light output is required, the purpose of increasing the ratio of the side-view light output to the front-view light output can be achieved by increasing the array density of the first prism structure (120) under the same condition that the included angle (X) of the first prism structure (120) is 90 degrees (for example, setting the array density to be greater than 33%).

Also, referring to FIG. 7, FIG. 7 is a graph showing the relationship between the viewing angle and brightness simulated using the optical film (100) according to one embodiment of the present disclosure and the optical film of the comparative example, respectively. Here, the optical film of the comparative example is a general cross-sectional prism sheet. As can be seen in FIG. 7, when light passes through and exits a general cross-sectional prism sheet, the light emission has a high light emission amount in the range of the light emission viewing angle from -40 degrees to +40 degrees. When light passes through and exits the optical film (100) of the embodiment of the present disclosure, the brightness of the light emitted from the optical film (100) in the range of the frontal viewing angle from -30 degrees to +30 degrees is lower than the brightness of the frontal viewing angle of the light emitted from the optical film of the comparative example, but the light emission amount at a viewing angle position exceeding the range of -40 degrees to +40 degrees significantly increases (for example, the relative brightness in the viewing angle range of -50 degrees to +50 degrees increases from 0.3 to 0.5). This means that the optical film (100) of the present embodiment can reduce the consumption of light emission energy at the frontal viewing angle by reducing the light emission brightness at the frontal viewing angle and improve the brightness at the side viewing angles of the driver's seat and passenger seat, thereby satisfying the usage requirements of a vehicle display.

Also, referring to FIG. 8, FIG. 8 is a schematic diagram showing the application of an optical film according to one embodiment of the present disclosure to a direct backlight module. The backlight module (500) of the present embodiment includes a light source (210), a diffusion film (510), a diffusion plate (520), and an optical film (100). In the backlight module (500) illustrated in FIG. 8, the optical film (100) is disposed in front of the light source (210). The diffusion film (510) and the diffusion plate (520) are disposed between the light source (210) and the optical film (100). Accordingly, light provided from the light source (210) can pass through the diffusion film (510) and the diffusion plate (520), be re-injected into the optical film (100), and be emitted by forming a wide viewing angle under the action of the optical film (100).

Also, referring to FIG. 9, FIG. 9 is a schematic diagram showing the application of an optical film according to one embodiment of the present disclosure to an edge-entry backlight module. The optical film (100) of the present embodiment may also be applied to an edge-entry backlight module (300). Here, the backlight module (300) includes a light source (310), a light guide plate (320), a film group (330), and an optical film (100). Here, the light source (310) is arranged adjacent to a light-incident surface (321) of the light guide plate (320), and the optical film (100) is arranged in front of a light-emission surface (322) of the light guide plate (320). The film group (330) is arranged between the light guide plate (320) and the optical film (100). Accordingly, light provided from a light source (310) is incident on a light guide plate (320) to form a surface light source and then is emitted, passes through a film group (330) and is re-injected into an optical film (100), and is emitted by forming a wide viewing angle under the action of the optical film (100).

Also, referring to FIG. 10, this is a schematic diagram showing a display device according to one embodiment of the present disclosure. The display device (400) of the present embodiment includes the backlight module (200) and the display panel (410) illustrated in FIG. 1. The display panel (410) is arranged in front of the backlight module (200). Accordingly, the display device (400) can also achieve the purpose of reducing the front viewing angle light output and increasing the side viewing angle light output through the design of the optical film (100) in the backlight module (200), and therefore, it will not be described further herein. Here, in the present embodiment, the application of the backlight module (200) illustrated in FIG. 1 to the display device (400) is only exemplified and is not intended to limit the present disclosure. The backlight modules of the other embodiments described above (for example, the backlight module (300) illustrated in FIG. 9) can all be applied to the display device to achieve the same effect of expanding the viewing angle.

Referring to FIG. 11, this is a schematic diagram showing the application of an optical film group according to one embodiment of the present disclosure to a direct backlight module. The optical film group (600) of the present embodiment can be mainly applied to the direct backlight module (700) illustrated in FIG. 11, or can be applied to the edge-entry backlight module (800) illustrated in FIG. 13 to increase the light emission viewing angle of the backlight module (700, 800). In the backlight module (700) illustrated in FIG. 11, the optical film group (600) is arranged in front of the light source (710). Here, the light source (710) includes a substrate (711) and a plurality of light-emitting units (712) arranged on the substrate (711). Accordingly, light provided from the light source (710) can directly pass through the optical film group (600) and be emitted from the optical film group (600).

As illustrated in FIG. 11, the optical film group (600) of the present embodiment includes a first film (610) and a second film (620). Here, the first film (610) has a first optical surface (612) and a plurality of first prism structures (611) arranged on the first optical surface (612), and the second film (620) has a second optical surface (622) and a plurality of second prism structures (621) arranged on the second optical surface (622). As illustrated in FIG. 11, the first prism structure (611) has a first extension direction (D1), and the second prism structure (621) has a second extension direction (D2), and the first extension direction (D1) is different from the second extension direction (D2). Accordingly, when light is incident on the optical film group (600) from the first optical surface (612), the first prism structure (611) can convert a portion of the direct light into light in a different direction, and further, the converted light is emitted through the second prism structure (621) on the second optical surface (622). Specifically, as illustrated in FIG. 11, under the action of the optical film (600), a portion of the light (e.g., light ray (L1)) can be emitted along the front-viewing direction through the gap (S2) between the first prism structures (611), and a portion of the light (e.g., light ray (L2)) can be emitted along the side-viewing direction under the action of the first prism structure (611). Here, the front-viewing direction means a direction in which the light is parallel to the normal direction of the optical film group (600), and an included angle (θ) is formed between the side-viewing direction and the front-viewing direction. More specifically, the frontal viewing direction is parallel to the normal line of the outgoing light of the optical film group (600), and the included angle (θ) between the side viewing direction and the normal line of the outgoing light is greater than 40 degrees and includes the end point value. In this way, the optical film group (600) of the present embodiment can further divert a part of the direct light to another viewing angle direction, thereby adjusting the size of the horizontal viewing angle to expand the viewing angle, so that the purpose of power saving can be achieved while matching a specific viewing angle and brightness without having to increase the current to improve the overall brightness.

In the present embodiment, each of the first prism structures (611) is a strip structure protruding from the first optical surface (612). In another embodiment, the first prism structure (611) may be a strip structure recessed from the first optical surface (612). In some embodiments, the included angle of the first extension direction (D1) and the second extension direction (D2) is 90 degrees. In addition, referring to FIG. 12, FIG. 12 is a partial schematic diagram showing an optical film group according to one embodiment of the present disclosure. In one embodiment, each of the first prism structures (611) has a first side surface (611a) and a second side surface (611b) that are connected to each other, and an included angle (X) is formed between the first side surface (611a) and the second side surface (611b). The first prism structure (611) has an array density (Y), a gap (P ₁ ) is provided between any two adjacent first prism structures (611), and a blank space (S2) has a width (W ₁ ). Here, the array density is calculated based on a function represented by Y = (P ₁ -W ₁ )/P ₁ .

In the present embodiment, when the ratio of the amount of light (L2) emitted in the side view direction to the amount of light (L1) emitted in the front view direction under the action of the optical film group (600) is 0.4 or more, that is, when the ratio of the amount of light emitted in the side view direction to the amount of light emitted in the front view direction of the optical film group (600) is 40% or more, the design of the first prism structure (611) must satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ .

Also, referring to FIG. 13, FIG. 13 is a schematic diagram showing the application of an optical film group according to one embodiment of the present disclosure to an edge entry backlight module. The optical film group (600) of the present embodiment can also be applied to an edge entry backlight module (800). Here, the backlight module (800) includes a light source (810), a light guide plate (820), a film group (830), and an optical film group (600). Here, the light source (810) is arranged adjacent to a light-incident surface (821) of the light guide plate (820), and the optical film group (600) is arranged in front of a light-emission surface (822) of the light guide plate (820). The film group (830) is arranged between the light guide plate (820) and the optical film group (600). Accordingly, light provided from a light source (810) is incident on a light guide plate (820) to form a surface light source and then is emitted, passes through a film group (830) and is re-injected into an optical film group (600), and is emitted by forming a wide viewing angle under the action of the optical film group (600).

Also, referring to FIG. 14, this is a schematic diagram showing a display device according to another embodiment of the present disclosure. The display device (900) of the present embodiment includes the backlight module (700) and the display panel (910) illustrated in FIG. 11. The display panel (910) is arranged in front of the backlight module (700). Accordingly, the display device (900) can also achieve the purpose of reducing the front viewing angle light output and increasing the side viewing angle light output through the design of the optical film group (600) among the backlight modules (700), and therefore, it is not described further herein. Here, in the present embodiment, the application of the backlight module (700) illustrated in FIG. 11 to the display device (900) is only exemplified and is not intended to limit the present disclosure. The backlight modules of the other embodiments described above (for example, the backlight module (800) illustrated in FIG. 13) can all be applied to the display device to achieve the same effect of expanding the viewing angle.

As can be seen from the above-described embodiments of the present disclosure, the present disclosure can improve the overall viewing range by mainly converting a part of direct light into a different viewing angle direction through the first prism structure and the second prism structure on the optical film or the optical film group, so that it can meet a specific viewing angle without having to increase the current to improve the overall brightness. Meanwhile, since the angle change and the array density of the first prism structure and the second prism structure can be designed using the relational formula of the present disclosure, the viewing angle requirements of different vehicle display devices can be satisfied.

100 : Optical Film
110 : Body
111 : 1st optical surface
112 : 2nd optical surface
120 : 1st prism structure
121 : 1st side
122 : 2nd side
130 : Second prism structure
200 : Backlight module
210 : Light source
211 : Substrate
212 : Light-emitting unit
300 : Backlight module
310 : Light source
320 : Light guide plate
321 : Ipgwangmyeon
322 : Chulgwangmyeon
330 : Film Group
400 : Display device
410 : Display Panel
500 : Backlight module
510 : Diffusion Film
520 : Diffusion plate
600 : Optical Film Group
610 : 1st film
611 : 1st prism structure
611a : 1st side
611b: Second side
612 : 1st optical surface
620 : 2nd film
621 : Second prism structure
622 : 2nd optical surface
700 : Backlight module
710 : Light source
711 : Substrate
712 : Light-emitting unit
800 : Backlight module
810 : Light source
820 : Light guide plate
821 : Ipgwangmyeon
822 : Chulgwangmyeon
830 : Film Group
900 : Display Device
910 : Display Panel
A : Area
B : Area
A+ : Area
D1 : 1st extension direction
D2 : 2nd extension direction
L1 : Ray
L2 : Ray
P₁ : Interval
S1 : Blank space
S2 : Blank space
W₁ : width
θ : angle of inclination
X : Collaboration

Claims (20)

In optical films,
A body having first and second optical surfaces opposing each other;
A plurality of first prism structures arranged on the first optical surface; and
It includes a plurality of second prism structures arranged on the second optical surface,
Each of the plurality of first prism structures has a first extension direction,
Each of the above plurality of second prism structures has a second extension direction,
An optical film, characterized in that the first extension direction is different from the second extension direction. In the first paragraph,
An optical film characterized in that the plurality of first prism structures have an array density (Y), each of the plurality of first prism structures has a first side surface and a second side surface that are connected to each other, an included angle (X) is formed between the first side surface and the second side surface, and the array density (Y) and the included angle (X) satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ . In the second paragraph,
An optical film characterized in that there is a gap between any two adjacent plurality of first prism structures, and the array density (Y) is calculated by the function Y = (P ₁ -W ₁ )/P ₁ , where P ₁ is the gap between any two adjacent plurality of first prism structures, and W ₁ is the width of each of the plurality of gaps. In the first paragraph,
An optical film, characterized in that each of the plurality of first prism structures is a strip structure that is sunken or protrudes from the first optical surface. In the first paragraph,
An optical film, characterized in that the included angle between the first extension direction and the second extension direction is 90 degrees. In the first paragraph,
An optical film characterized in that when light is incident on the body from one of the first optical surface and the second optical surface and is emitted from the other of the first optical surface and the second optical surface, a portion of the light is emitted in a frontal viewing direction, and another portion of the light is emitted in a side viewing direction, wherein a ratio of the amount of light emitted in the side viewing direction to the amount of light emitted in the frontal viewing direction is greater than 0.4 and includes an endpoint value. In Article 6,
An optical film characterized in that the frontal viewing direction is parallel to the normal line of the light emitted from the optical film, and the included angle between the side viewing direction and the normal line of the light emitted is greater than 40 degrees and includes an end point value. In the backlight module,
A light guide plate having a light-input surface and a light-emission surface;
A light source positioned adjacent to the light-incident surface;
An optical film according to any one of claims 1 to 7, arranged in front of the light-emitting surface; and
A backlight module characterized by including a film group positioned between the optical film and the light guide plate. In the backlight module,
A light source comprising a substrate and a plurality of light-emitting units arranged on the substrate; and
A backlight module characterized by including an optical film according to any one of claims 1 to 7 arranged in front of the light source. In display devices,
A backlight module according to Article 8 or 9; and
A display device characterized by including a display panel arranged in front of the backlight module. In the optical film group,
A first film having a first optical surface and a plurality of first prism structures arranged on the first optical surface; and
A second film comprising a second optical surface and a plurality of second prism structures arranged on the second optical surface,
The first optical surface and the second optical surface face opposite directions,
Each of the above plurality of first prism structures has a first extension direction,
Each of the above plurality of second prism structures has a second extension direction,
An optical film group characterized in that the first extension direction is different from the second extension direction. In Article 11,
An optical film group characterized in that the plurality of first prism structures have an array density (Y), each of the plurality of first prism structures has a first side surface and a second side surface that are connected to each other, an included angle (X) is formed between the first side surface and the second side surface, and the array density (Y) and the included angle (X) satisfy the relationship Y≥0.441+0.01249X-3.2875* ^10-4 X ² +1.95833* ^10-6 X ³ . In Article 12,
An optical film group characterized in that there is a gap between any two adjacent plurality of first prism structures, and the array density (Y) is calculated by the function Y = (P ₁ -W ₁ )/P ₁ , where P ₁ is the gap between any two adjacent plurality of first prism structures, and W ₁ is the width of each of the plurality of gaps. In Article 11,
An optical film group characterized in that each of the plurality of first prism structures is a strip structure that is sunken or protrudes from the first optical surface. In Article 11,
An optical film group characterized in that the included angle between the first extension direction and the second extension direction is 90 degrees. In Article 11,
An optical film group characterized in that when light is incident on the body from one of the first optical surface and the second optical surface and is emitted from the other of the first optical surface and the second optical surface, a portion of the light is emitted in a frontal viewing direction, and another portion of the light is emitted in a side viewing direction, wherein a ratio of the amount of light emitted in the side viewing direction to the amount of light emitted in the frontal viewing direction is greater than 0.4 and includes an end point value. In Article 16,
An optical film group characterized in that the frontal viewing direction is parallel to the normal line of the exit light of the optical film group, and the included angle between the side viewing direction and the normal line of the exit light is greater than 40 degrees and includes an end point value. In the backlight module,
A light guide plate having a light-input surface and a light-emission surface;
A light source positioned adjacent to the light-incident surface;
An optical film group according to any one of claims 11 to 17, arranged in front of the light-emitting surface; and
A backlight module characterized by including a film group positioned between the optical film group and the light guide plate. In the backlight module,
A light source comprising a substrate and a plurality of light-emitting units arranged on the substrate; and
A backlight module characterized by including an optical film group according to any one of claims 11 to 17 arranged in front of the light source. In display devices,
A backlight module according to Article 18 or 19; and
A display device characterized by including a display panel arranged in front of the backlight module.