Optical film structure and display device

Abstract

The embodiment of the present application discloses an optical film structure and a display device. In the optical film structure of the embodiment of the present application, the inclination angle of the first prism is between 60 degrees and 80 degrees. The inclination angle of the second prism is between 20 degrees and 40 degrees, and the second prism has a second vertex angle, which is an obtuse angle. The optical film structure of the embodiment of the present application adopts a double prism film architecture, and by limiting the inclination angle of the first prism to between 60 degrees and 80 degrees, limiting the inclination angle of the second prism to between 20 degrees and 40 degrees, and replacing the second vertex angle from the right angle of the prior art to an obtuse angle, by transferring part of the light output in the vertical and horizontal directions to the lateral direction, the brightness of the light output in the lateral direction is increased to meet the brightness and viewing angle specifications of the TCO certification standard, and the light efficiency is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to an optical film structure and a display device. Background Art

[0002] With the advent of the display industry energy standard ES9.0, LCD screens have increasingly stringent requirements for contrast, energy efficiency, viewing angle specifications, and module quality. Most existing modules need to be TCO (Swedish Labor Confederation) Certified (certified) standard specifications. The most critical ones are to meet the power consumption requirements of ES9.0 and the brightness and viewing angle requirements of the TCO certification standard. The brightness and viewing angle requirements of the TCO certification standard are: in landscape mode, when the screen is rotated ±30° around the vertical axis passing through the center of the screen, the maximum brightness (L max ) and minimum brightness (L min ) ratio (L max / L min ) must be ≤1.73; in landscape mode, when the screen rotates ±15° around the horizontal axis passing through the center of the screen, L max With L min The maximum value of the ratio must be ≤1.73. For details on the brightness and viewing angle requirements in the TCO certification standard, please refer to "TCO Certified-Generation 8, for displays".

[0003] In related technologies, such as Figure 1 As shown, the general optical film structure adopts a structure of two diffuser sheets ks superimposed on a prism enhancement sheet lj. The inclination angle of the prism strips in the prism enhancement sheet lj is 0 degrees, and the prism vertex angle of the prism enhancement sheet lj is 90 degrees. The two diffuser sheets ks are placed on the light guide plate to fully uniformize the light passing through the light guide plate. The prism enhancement sheet lj allows the vertical light to be collected, so the viewing angle in the horizontal direction will be better. Although the display module with this structure meets the TCO brightness and viewing angle specifications, the light efficiency is not high. Summary of the Invention

[0004] The embodiments of the present application provide an optical film structure and a display device, which can improve the brightness of side-emitting light, so that the corresponding display device can improve the light efficiency while meeting the brightness and viewing angle specifications in the TCO certification standard.

[0005] The present invention provides an optical film structure, which includes:

[0006] Diffuser membrane;

[0007] a first prism film, the first prism film being disposed on the diffusion film, the first prism film comprising a first substrate and first prisms disposed on a side of the first substrate away from the diffusion film, wherein the inclination angle of the first prisms is between 60 degrees and 80 degrees;

[0008] a second prism film, wherein the second prism film is arranged on a side of the first prism film away from the diffusion film, the second prism film includes a second substrate and a second prism arranged on a side of the second substrate away from the diffusion film, the inclination angle of the second prism is between 20 degrees and 40 degrees, the second prism has a second vertex angle, the second vertex angle is located on a side of the second prism away from the second substrate, and the second vertex angle is an obtuse angle.

[0009] Optionally, in some embodiments of the present application, the second vertex angle is between 95 degrees and 105 degrees.

[0010] Optionally, in some embodiments of the present application, the first prism has a first vertex angle, the first vertex angle is located on a side of the first prism away from the first substrate, and the first vertex angle is 90 degrees.

[0011] Optionally, in some embodiments of the present application, the inclination angle of the first prism is 70 degrees, and the inclination angle of the second prism is 30 degrees.

[0012] Optionally, in some embodiments of the present application, the width of the first prism is between 38 microns and 56 microns, and the height of the first prism is between 18 microns and 28 microns.

[0013] Optionally, in some embodiments of the present application, the width of the second prism is between 24 microns and 38 microns, and the height of the first prism is between 10 microns and 18 microns.

[0014] Optionally, in some embodiments of the present application, the first prism and the second prism are both isosceles triangular prisms. In the positive projection pattern of the stacked first prism film and the second prism film, a plurality of the first prisms are arranged in parallel and extend along a first direction, and a plurality of the second prisms are arranged in parallel and extend along a second direction, and the first direction and the second direction intersect.

[0015] Optionally, in some embodiments of the present application, the angle between the first direction and the second direction is between 20 degrees and 60 degrees.

[0016] Optionally, in some embodiments of the present application, the distance between the top edges of two adjacent first prisms is equal to the width of the first prism, and the distance between the top edges of two adjacent second prisms is equal to the width of the second prism.

[0017] Optionally, in some embodiments of the present application, the second prism film further includes a second haze layer, and the second haze layer is disposed on a side of the second substrate close to the first prism film.

[0018] Optionally, in some embodiments of the present application, the haze of the second haze layer is between 20% and 40%.

[0019] Correspondingly, an embodiment of the present application further provides a backlight module, which includes the optical film structure as described in any one of the above embodiments.

[0020] Correspondingly, an embodiment of the present application further provides a display device, which includes a liquid crystal panel and a backlight module as described in any one of the above embodiments, wherein the liquid crystal panel is arranged on the light-emitting side of the backlight module.

[0021] Optionally, in some embodiments of the present application, the brightness ratio of the TCO at a horizontal viewing angle is between 1.32 and 1.71, and the brightness ratio of the TCO at a vertical viewing angle is between 1.53 and 1.73.

[0022] The optical film structure of the embodiment of the present application adopts a diffusion film, a first prism film and a second prism film stacked in sequence. The first prism film includes a first substrate and a first prism arranged on the side of the first substrate away from the diffusion film, and the tilt angle of the first prism is between 60 degrees and 80 degrees. The second prism film includes a second substrate and a second prism arranged on the side of the second substrate away from the diffusion film, and the tilt angle of the second prism is between 20 degrees and 40 degrees. The second prism has a second vertex angle, which is located on the side of the second prism away from the second substrate, and the second vertex angle is an obtuse angle. Among them, the optical film structure of the embodiment of the present application adopts a dual prism film architecture, and by limiting the tilt angle of the first prism to between 60 degrees and 80 degrees, the tilt angle of the second prism to between 20 degrees and 40 degrees, and replacing the second vertex angle from the right angle of the prior art to an obtuse angle, by transferring part of the light output in the vertical and horizontal directions to the lateral direction, the brightness of the light output in the lateral direction is improved, so as to meet the brightness and viewing angle specifications of the TCO certification standard and improve the light efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of an optical film structure in related art;

[0024] Figure 2 1. is a schematic diagram of the full-viewing angle brightness of a display module equipped with the optical film structure in the related art;

[0025] Figure 3 is a three-dimensional schematic diagram of the optical film structure provided in an embodiment of the present application;

[0026] Figure 4Schematic diagram of the cross-sectional structure of the first prism film and the second prism film in the optical film structure provided by the embodiment of the present application;

[0027] Figure 5 1 is a schematic orthographic projection diagram of a first prism film of an optical film structure provided in an embodiment of the present application;

[0028] Figure 6 1 is a schematic orthographic projection diagram of a second prism film of the optical film structure provided in an embodiment of the present application;

[0029] Figure 7 is an orthographic projection diagram of a stack of a first prism film and a second prism film in an optical film structure provided by an embodiment of the present application;

[0030] Figure 8 It is a structural schematic diagram of the display device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0031] The following will clearly and completely describe the technical solutions in the embodiments of the present application in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present application. In addition, it should be understood that the specific implementation methods described herein are only used to illustrate and explain the present application and are not used to limit the present application. In the present application, unless otherwise specified, the directional words used, such as "upper" and "lower", generally refer to the upper and lower parts of the device in actual use or working state, specifically the drawing direction in the accompanying drawings; while "inside" and "outside" refer to the outline of the device; the terms "first", "second", "third", etc. are used only as labels and do not impose numerical requirements or establish an order.

[0032] The embodiments of the present application provide an optical film structure, a backlight module, and a display device, which are described in detail below. It should be noted that the order of description of the following embodiments does not limit the preferred order of the embodiments.

[0033] In the related art of the background technology, the optical film structure gx adopts the structure of two diffusion sheets ks superimposed on a prism enhancement sheet lj. The prism strips in the prism enhancement sheet lj have an inclination angle of 0 degrees and the prism vertex angle of the prism enhancement sheet lj is 90 degrees. The brightness of the display module corresponding to the optical film structure gx is as follows: Figure 2 As shown, according to Figure 2 , it can be seen that the light distribution is relatively uniform in all directions, both horizontally and vertically.

[0034] It should be understood that the TCO horizontal viewing angle brightness value refers to the maximum brightness (L) when the screen is rotated ±30° around the vertical axis passing through the center of the screen in landscape mode. max ) and minimum brightness (L min ) ratio (L max / L min ). The TCO vertical viewing angle brightness ratio refers to: in landscape mode, when the screen is rotated ±15° around the horizontal axis passing through the center of the screen, L max With L min The maximum value of the ratio.

[0035] Among them, in landscape mode, when the screen is rotated +30° around the vertical axis passing through the center of the screen, the brightness of the left test point corresponds to the viewing angle brightness of 40° in the full viewing angle, and the brightness of the right test point corresponds to the viewing angle brightness of 17° in the full viewing angle. In landscape mode, when the screen is rotated +15° around the horizontal axis passing through the center of the screen, the brightness of the upper test point corresponds to the viewing angle brightness of 22° in the full viewing angle, and the brightness of the lower test point corresponds to the viewing angle brightness of 7.6° in the full viewing angle. Figure 2 It can be seen that the measured TCO vertical viewing angle brightness ratio has a large margin compared with the standard TCO vertical viewing angle brightness ratio (1.73).

[0036] Therefore, the optical film structure of the embodiment of the present application adopts a diffusion film, a first prism film and a second prism film stacked in sequence. The first prism film includes a first substrate and a first prism arranged on the side of the first substrate away from the diffusion film, and the tilt angle of the first prism is between 60 degrees and 80 degrees. The second prism film includes a second substrate and a second prism arranged on the side of the second substrate away from the diffusion film, and the tilt angle of the second prism is between 20 degrees and 40 degrees. The second prism has a second vertex angle, which is located on the side of the second prism away from the second substrate, and the second vertex angle is an obtuse angle. Among them, the optical film structure of the embodiment of the present application adopts a dual prism film architecture, and by limiting the tilt angle of the first prism to between 60 degrees and 80 degrees, the tilt angle of the second prism to between 20 degrees and 40 degrees, and replacing the second vertex angle from the right angle of the prior art to an obtuse angle, by transferring part of the light output in the vertical and horizontal directions to the lateral direction, the brightness of the light output in the lateral direction is improved, so as to meet the brightness and viewing angle specifications of the TCO certification standard while improving the light efficiency.

[0037] Please refer to Figures 3 to 6 The embodiment of the present application provides an optical film structure 100 , which includes: a diffusion film 11 , a first prism film 12 and a second prism film 13 .

[0038] The first prism film 12 is disposed on the diffusion film 11. The first prism film 12 includes a first substrate 121 and first prisms 122 disposed on a side of the first substrate 121 away from the diffusion film 11. The tilt angle θ1 of the first prisms 122 is between 60 degrees and 80 degrees.

[0039] The second prism film 13 is disposed on a side of the first prism film 12 away from the diffusion film 11. The second prism film 13 includes a second substrate 131 and second prisms 132 disposed on a side of the second substrate 131 away from the diffusion film 11. The second prisms 132 have an inclination angle θ2 between 20 and 40 degrees. The second prisms 132 have a second vertex angle α2, which is located on the side of the second prisms 132 away from the second substrate 131. The second vertex angle α2 is an obtuse angle.

[0040] The optical film structure 100 of the embodiment of the present application adopts a diffusion film 11 and a double prism film (12, 13) structure, and by limiting the inclination angle θ1 of the first prism 122 to between 60 degrees and 80 degrees, limiting the inclination angle θ2 of the second prism 132 to between 20 degrees and 40 degrees, and replacing the second vertex angle α2 from the right angle of the prior art to an obtuse angle, part of the light output in the vertical and horizontal directions is transferred to the lateral direction to increase the brightness of the light output in the lateral direction, so as to meet the brightness and viewing angle specifications of the TCO certification standard while improving the light efficiency.

[0041] The second vertex angle α2 is replaced by an obtuse angle from the right angle in the prior art, which can reduce the light collecting capability in the vertical direction to adjust the TCO viewing angle brightness ratio.

[0042] It should be noted that the tilt angle θ1 of the first prism 122 refers to the angle between the extension direction of the first prism 122 and the horizontal line x in the orthographic projection pattern of the first prism film 12. It is also the angle of the first prism 122 rotated counterclockwise from the horizontal line x. The tilt angle θ2 of the second prism 132 refers to the angle between the extension direction of the second prism 132 and the same horizontal line x in the orthographic projection pattern of the second prism film 13. It is also the angle of the second prism 132 rotated counterclockwise from the horizontal line x. Here, the horizontal line x is the only horizontal line.

[0043] For example, if the optical film structure 100 is rectangular as a whole, when the optical film structure 100 is upright, the bottom side of the optical film structure is parallel to the horizontal line x, and the bottom side of the optical film structure 100 is used as a reference for the horizontal line x.

[0044] Alternatively, in one embodiment, the horizontal line x is a straight line parallel to the short side of the rectangular first prism film 12 .

[0045] Optionally, in some embodiments, when the optical film structure 100 and the liquid crystal panel are assembled to form a display device, the horizontal line x is parallel to the short side of the rectangular sub-pixel in the liquid crystal panel.

[0046] Optionally, the inclination angle θ1 of the first prism 122 can be 60 degrees, 61 degrees, 62 degrees, 63 degrees, 64 degrees, 65 degrees, 66 degrees, 67 degrees, 68 degrees, 69 degrees, 70 degrees, 71 degrees, 72 degrees, 73 degrees, 74 degrees, 75 degrees, 76 degrees, 77 degrees, 78 degrees, 79 degrees or 80 degrees, etc.

[0047] The tilt angle θ2 of the second prism 132 can be 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees or 40 degrees, etc.

[0048] Optionally, the tilt angle θ1 of the first prism 122 is 70 degrees, and the tilt angle θ2 of the second prism 132 is 30 degrees. This configuration can improve the brightness of the light emitted from the high-gain center and meet the TCO viewing angle brightness value while being adaptable to more types of liquid crystal panels.

[0049] In one embodiment, the second vertex angle α2 is between 95 degrees and 105 degrees.

[0050] It is understandable that please refer to Figure 4 When the prism's vertex angle is acute, the center's brightness gain is high, but visibility at side angles is poor. When the prism's vertex angle is obtuse, the center's brightness gain is low, but visibility at side angles is good. When the triangular prism's vertex angle is 90 degrees, the prism has an excellent convergence effect on light. However, as the vertex angle increases, its convergence effect gradually deteriorates, and so does the focusing effect. Therefore, setting the second vertex angle α2 between 95 and 105 degrees ensures a certain focusing effect while reducing the convergence effect of vertical light to increase the divergence effect, thereby adjusting the TCO's viewing angle brightness.

[0051] Optionally, the second vertex angle α2 may be 95 degrees, 96 degrees, 97 degrees, 98 degrees, 99 degrees, 100 degrees, 101 degrees, 102 degrees, 103 degrees, 104 degrees or 105 degrees, etc.

[0052] In one embodiment, the first prism 122 has a first vertex angle α1, and the first vertex angle α1 is located on a side of the first prism 122 away from the first substrate 121. The first vertex angle α1 is 90 degrees.

[0053] It can be understood that, in the present application, the first vertex angle α1 of the first prism 122 is set to a right angle, which can balance the central brightness gain and the visibility at the side viewing angle.

[0054] Optionally, the first vertex angle α1 may also be appropriately adjusted to a small obtuse angle according to the TCO viewing angle brightness value.

[0055] Please refer to Figure 5-6 In one embodiment, the width k1 of the first prism 122 is between 38 micrometers and 56 micrometers, and the height g1 of the first prism 122 is between 18 micrometers and 28 micrometers.

[0056] Optionally, in one embodiment, the width k2 of the second prism 132 is between 24 micrometers and 38 micrometers, and the height g2 of the second prism 132 is between 10 micrometers and 18 micrometers.

[0057] It is understandable that the prism width and height are positively correlated. Keeping the top angle unchanged, the larger the width of the prism and the larger the height, the better the convergence effect on light and the worse the divergence effect on light. The present application adjusts the central brightness and lateral light output brightness of the optical film structure 100 by setting the width k1 of the first prism 122 to be between 38 microns and 56 microns, the height g1 of the first prism 122 to be between 18 microns and 28 microns, the width k2 of the second prism 132 to be between 24 microns and 38 microns, and the height g2 of the first prism 122 to be between 10 microns and 18 microns to match the TCO viewing angle brightness value and improve the light output gain.

[0058] Optionally, the width k1 of the first prism 122 is greater than the width k2 of the second prism 132, and the height of the first prism 122 is greater than the height of the second prism 132, so that the first prism film 12 mainly converges light to ensure the central light output efficiency of the optical film structure 100, and the second prism film 13 mainly diverges light appropriately to facilitate adjustment of the light output efficiency of the entire optical film structure 100 and the visibility at the side viewing angle.

[0059] Optionally, the width k1 of the first prism 122 may be 38 microns, 39 microns, 40 microns, 41 microns, 42 microns, 43 microns, 44 microns, 45 microns, 46 microns, 47 microns, 48 microns, 49 microns, 50 microns, 51 microns, 52 microns, 53 microns, 54 microns, 55 microns or 56 microns, etc.

[0060] The height g1 of the first prisms 122 may be 18 micrometers, 19 micrometers, 20 micrometers, 21 micrometers, 22 micrometers, 23 micrometers, 24 micrometers, 25 micrometers, 26 micrometers, 27 micrometers, or 28 micrometers, etc.

[0061] The width k2 of the second prism 132 may be 24 microns, 25 microns, 26 microns, 27 microns, 28 microns, 29 microns, 30 microns, 31 microns, 32 microns, 33 microns, 34 microns, 35 microns, 36 microns, 37 microns, or 38 microns, etc.

[0062] The height g2 of the first prisms 122 may be 10 micrometers, 11 micrometers, 12 micrometers, 13 micrometers, 14 micrometers, 15 micrometers, 16 micrometers, 17 micrometers, or 18 micrometers, etc.

[0063] In one embodiment, the distance L1 between the top edges of two adjacent first prisms 122 is equal to the width k1 of the first prism 122 , and the distance L2 between the top edges of two adjacent second prisms 132 is equal to the width k2 of the second prism 132 .

[0064] That is, the first prisms 122 are continuously connected along a direction perpendicular to their extension, with the spacing between adjacent first prisms 122 being zero; the second prisms 132 are continuously connected along a direction perpendicular to their extension, with the spacing between adjacent second prisms 132 being zero. This arrangement maximizes the number of first prisms 122 and second prisms 132, increasing the arrangement density and thereby improving the brightness of the center light output and the side view brightness.

[0065] Please refer to Figure 7 In one embodiment, the first prisms 122 and the second prisms 132 are both isosceles triangular prisms. In the orthographic projection pattern of the stacked first prism film 12 and the second prism film 13, the plurality of first prisms 122 are arranged in parallel and extend along a first direction, and the plurality of second prisms 132 are arranged in parallel and extend along a second direction, where the first direction and the second direction intersect. An angle β between the first direction and the second direction is between 20 degrees and 60 degrees.

[0066] It is understood that the angle β between the first direction and the second direction is determined by the inclination angle θ1 of the first prism 122 and the inclination angle θ2 of the second prism 132. Therefore, setting the angle β between the first direction and the second direction between 20 degrees and 60 degrees increases the lateral brightness of the light output, thereby meeting the brightness and viewing angle specifications of the TCO certification standard while improving light efficiency.

[0067] Optionally, the angle β between the first direction and the second direction can be 20 degrees, 21 degrees, 22 degrees, 23 degrees, 24 degrees, 25 degrees, 26 degrees, 27 degrees, 28 degrees, 29 degrees, 30 degrees, 31 degrees, 32 degrees, 33 degrees, 34 degrees, 35 degrees, 36 degrees, 37 degrees, 38 degrees, 39 degrees, 40 degrees, 41 degrees, 42 degrees, 43 degrees, 44 degrees, 45 degrees, 46 degrees, 47 degrees, 48 degrees, 49 degrees, 50 degrees, 51 degrees, 52 degrees, 53 degrees, 54 degrees, 55 degrees, 56 degrees, 57 degrees, 58 degrees, 59 degrees or 60 degrees, etc.

[0068] Optionally, the thickness of the first substrate 121 is smaller than the thickness of the second substrate 131 .

[0069] Optionally, the first substrate 121 and the first prisms 122 are integrally formed and made of the same material. The second substrate 131 and the second prisms 132 are integrally formed and made of the same material.

[0070] The refractive index of the first prism 122 is between 1.54 and 1.56, and the refractive index of the second prism 132 is between 1.52 and 1.54. The refractive index of the first prism 122 is slightly greater than that of the second prism 132 .

[0071] It is understood that the greater the prism's refractive index, the greater the angle of light deflection, and the better the light convergence effect. Therefore, the above arrangement makes the first prism film 12 have a better light-focusing effect than the second prism film 13. On the other hand, the similar refractive indices of the first prism film 12 and the second prism film 13 make it easier to infer and determine the degree of light deflection, thereby better adjusting the center and lateral light output brightness.

[0072] Alternatively, in one embodiment, the first substrate 121 and the first prisms 122 may be made of different materials, and the first prisms 122 may be formed on the first substrate 121 . The second substrate 131 and the second prisms 132 may also be made of different materials, and the second prisms 132 may be formed on the second substrate 131 .

[0073] In one embodiment, the first prism film 12 may further include a first haze layer 123 . The first haze layer 123 is disposed on a side of the first substrate 121 away from the second prism film 13 .

[0074] The first haze layer 123 can better evenly distribute the incident light entering the first prism film 12 , thereby balancing the central light output efficiency and the visibility of the lateral light output.

[0075] Optionally, the haze of the first haze layer 123 is between 3% and 20%, for example, it can be 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%, etc.

[0076] The second prism film 13 further includes a second haze layer 133 . The second haze layer 133 is disposed on a side of the second substrate 131 close to the first prism film 12 .

[0077] The second haze layer 133 can better even the incident light entering the second prism film 13 , so as to balance the central light output efficiency and the visibility of the lateral light output.

[0078] Optionally, the haze of the second haze layer 133 is between 20% and 40%, for example, it can be 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39% or 40%, etc.

[0079] Optionally, the haze of the first haze layer 123 is smaller than the haze of the second haze layer 133, thereby improving the divergence effect of the second prism film 13 and facilitating better improvement of the side view brightness. The haze ranges of the two are selected to better match different liquid crystal panels to meet the TCO viewing angle brightness and center light efficiency gain.

[0080] The overall refractive index of the first prism film 12 having the first haze layer 123 is between 1.52 and 1.56, such as 1.52, 1.53, 1.54, 1.55, or 1.56. The overall refractive index of the second prism film 13 having the second haze layer 133 is between 1.52 and 1.56, such as 1.52, 1.53, 1.54, 1.55, or 1.56.

[0081] Correspondingly, an embodiment of the present application further provides a backlight module, which includes the optical film structure 100 according to any one of the above embodiments.

[0082] Optionally, the backlight module further includes a light guide plate, and the optical film structure 100 is arranged on the light emitting surface of the light guide plate.

[0083] It should be noted that the optical film structure 100 of the backlight module of this embodiment has the same structure as the optical film structure 100 of the above embodiment, and therefore will not be described in detail here.

[0084] Please refer to Figure 8 , an embodiment of the present application further provides a display device PN, which includes a liquid crystal panel LC and a backlight module BL as described in any one of the above embodiments, wherein the liquid crystal panel LC is arranged on the light-emitting side of the backlight module BL.

[0085] It should be noted that the structure of the backlight module BL of this embodiment is similar to or the same as that of the backlight module of the above embodiment, and therefore will not be described in detail here.

[0086] It is understandable that in the display device PN, by disposing the first prism film 12 and the second prism film 13 in the optical film structure 100, the display device PN can meet the TCO viewing angle brightness value and improve the light extraction efficiency of the center.

[0087] Specifically, in the display device PN of the embodiment of the present application, the optical film structure 100 adopts a diffusion film 11 and a double prism film (12, 13) architecture, and by limiting the inclination angle θ1 of the first prism 122 to between 60 degrees and 80 degrees, limiting the inclination angle θ2 of the second prism 132 to between 20 degrees and 40 degrees, and replacing the second vertex angle α2 from the right angle of the prior art to an obtuse angle, part of the light output in the vertical and horizontal directions is transferred to the lateral direction to increase the brightness of the light output in the lateral direction, so as to meet the brightness and viewing angle specifications of the TCO certification standard while improving the light efficiency.

[0088] Please refer to Tables 1 through 3, which contain experimental data for the center brightness gain and TCO viewing angle brightness values corresponding to three optical film structures. The three optical film structures are DDP architecture, DPP architecture, and D+P-variable angle + P-variable angle architecture. DF stands for diffuser film, P stands for prism film, and Px degrees refers to a prism tilt angle θ of x degrees. For example, P-90 degrees refers to a prism tilt angle θ of 90 degrees. Tables 1 through 3 correspond to different panel models, and this panel model is from China Star Optoelectronics.

[0089] Among the three optical film structures, the DPP structure and the D+P-Vari-Angle + P-Vari-Angle structure differ only in the prism tilt angle of the middle film; the DPP structure and the D+P-Vari-Angle + P-Vari-Angle structure differ only in the prism tilt angle of the top film. The prism vertex angle of the middle film in both the DPP structure and the D+P-Vari-Angle + P-Vari-Angle structure is 90 degrees. The prism vertex angle of the top film in the DPP structure and the D+P-Vari-Angle + P-Vari-Angle structure was tested as 96 degrees.

[0090] The specific test data is as follows:

[0091]

[0092] As can be seen from Table 1, in the DPP architecture, although the brightness gain of the display device is high, it does not meet the TCO viewing angle brightness specification.

[0093] In the D+P-variable angle + P-variable angle architecture, when the prism tilt angle θ of the middle film is 80 degrees and the prism tilt angle of the top film is 20 degrees, 25 degrees, 30 degrees, and 40 degrees; when the prism tilt angle θ of the middle film is 70 degrees and the prism tilt angle of the top film is 15 degrees, 20 degrees, 30 degrees, and 40 degrees; when the prism tilt angle θ of the middle film is 60 degrees and the prism tilt angle of the top film is 20 degrees and 30 degrees; the display devices both meet the TCO viewing angle and brightness specifications and improve the light efficiency.

[0094] Please continue to refer to Table 2:

[0095]

[0096] As can be seen from Table 2, in the DPP architecture, although the brightness gain of the display device is high, it does not meet the TCO viewing angle brightness specification.

[0097] In the D+P-variable angle + P-variable angle architecture, when the prism tilt angle θ of the middle film is 80 degrees and the prism tilt angle of the top film is 25 degrees, 30 degrees, and 40 degrees; when the prism tilt angle θ of the middle film is 70 degrees and the prism tilt angle of the top film is 20 degrees, 30 degrees, and 40 degrees; when the prism tilt angle θ of the middle film is 60 degrees and the prism tilt angle of the top film is 20 degrees and 30 degrees; the display devices both meet the TCO viewing angle and brightness specifications and improve the light efficiency.

[0098] Please continue to refer to Table 3:

[0099]

[0100] As shown in Table 3, in the DPP architecture, although the brightness gain of the display device is high, it does not meet the TCO viewing angle brightness specification.

[0101] In the D+P-variable angle + P-variable angle architecture, when the prism tilt angle θ of the middle film is 80 degrees and the prism tilt angle of the top film is 30 degrees and 40 degrees; when the prism tilt angle θ of the middle film is 70 degrees and the prism tilt angle of the top film is 20 degrees, 30 degrees and 40 degrees; when the prism tilt angle θ of the middle film is 60 degrees and the prism tilt angle of the top film is 20 degrees and 30 degrees; when the prism tilt angle θ of the middle film is 50 degrees and the prism tilt angle of the top film is 10 degrees; the display devices all meet the TCO viewing angle and brightness specifications and improve the light efficiency.

[0102] The above data shows that different panel configurations can produce different center brightness gain and TCO viewing angle brightness ratios. This means that by selecting prisms with different tilt angles based on different panel types, the TCO viewing angle brightness specifications can be met while also improving light efficiency.

[0103] Therefore, in the embodiment of the present application, the inclination angle θ1 of the first prism 122 is between 60 degrees and 80 degrees, the inclination angle θ2 of the second prism 132 is between 20 degrees and 40 degrees, and the second vertex angle α2 is an obtuse angle, which can meet the TCO viewing angle brightness specifications and improve the light efficiency.

[0104] Optionally, according to the above table data, the brightness ratio of the TCO horizontal viewing angle is between 1.32 and 1.71, and the brightness ratio of the TCO vertical viewing angle is between 1.53 and 1.73.

[0105] The optical film structure 100 of the display device PN according to an embodiment of the present application comprises a diffusion film 11, a first prism film 12, and a second prism film 13 stacked in sequence. The first prism film 12 comprises a first substrate 121 and first prisms 122 disposed on the side of the first substrate 121 away from the diffusion film 11. The first prisms 122 have an inclination angle between 60 and 80 degrees. The second prism film 13 comprises a second substrate 131 and second prisms 132 disposed on the side of the second substrate 131 away from the diffusion film 11. The second prisms 132 have an inclination angle between 20 and 40 degrees. The second prisms 132 have a second vertex angle α2, which is located on the side of the second prisms 132 away from the second substrate 131. The second vertex angle α2 is an obtuse angle. Among them, the optical film structure 100 of the embodiment of the present application adopts a dual prism film structure, and by limiting the inclination angle of the first prism θ1 to between 60 degrees and 80 degrees, limiting the inclination angle θ2 of the second prism to between 20 degrees and 40 degrees, and replacing the second vertex angle α2 from the right angle of the prior art to an obtuse angle, part of the light output in the vertical and horizontal directions is transferred to the lateral direction, so as to increase the brightness of the light output in the lateral direction to meet the brightness and viewing angle specifications of the TCO certification standard and improve the light efficiency.

[0106] The above is a detailed introduction to an optical film structure, backlight module and display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for technical personnel in this field, based on the ideas of the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An optical film structure, characterized in that: include: Diffuser membrane; a first prism film, the first prism film being disposed on the diffusion film, the first prism film comprising a first substrate and first prisms disposed on a side of the first substrate away from the diffusion film, wherein the inclination angle of the first prisms is between 60 degrees and 80 degrees; a second prism film, the second prism film being disposed on a side of the first prism film away from the diffusion film, the second prism film comprising a second substrate and second prisms disposed on a side of the second substrate away from the diffusion film, the second prisms having an inclination angle ranging from 20 degrees to 40 degrees, the second prisms having a second vertex angle, the second vertex angle being located on a side of the second prisms away from the second substrate, and the second vertex angle being an obtuse angle; The refractive index of the first prism is between 1.54 and 1.56, the refractive index of the second prism is between 1.52 and 1.54, and the refractive index of the first prism is greater than the refractive index of the second prism.

2. The optical film structure according to claim 1, wherein: The second vertex angle is between 95 degrees and 105 degrees.

3. The optical film structure according to claim 2, wherein: The first prism has a first vertex angle, which is located on a side of the first prism away from the first substrate, and is 90 degrees.

4. The optical film structure according to claim 3, characterized in that: The inclination angle of the first prism is 70 degrees, and the inclination angle of the second prism is 30 degrees.

5. The optical film structure according to claim 3, wherein: The width of the first prism is between 38 micrometers and 56 micrometers, and the height of the first prism is between 18 micrometers and 28 micrometers.

6. The optical film structure according to claim 4, characterized in that: The width of the second prism is between 24 micrometers and 38 micrometers, and the height of the first prism is between 10 micrometers and 18 micrometers.

7. The optical film structure according to claim 6, characterized in that: The first prism and the second prism are both isosceles triangular prisms. In the orthographic projection pattern of the stacked first prism film and the second prism film, multiple first prisms are arranged in parallel and extend along a first direction, and multiple second prisms are arranged in parallel and extend along a second direction, and the first direction and the second direction intersect.

8. The optical film structure according to claim 7, characterized in that: An included angle between the first direction and the second direction is between 20 degrees and 60 degrees.

9. The optical film structure according to claim 7, wherein: The distance between the top edges of two adjacent first prisms is equal to the width of the first prism, and the distance between the top edges of two adjacent second prisms is equal to the width of the second prism.

10. The optical film structure according to any one of claims 3 to 9, characterized in that: The second prism film further includes a second haze layer, and the second haze layer is disposed on a side of the second substrate close to the first prism film.

11. The optical film structure according to claim 10, wherein: The haze of the second haze layer is between 20% and 40%.

12. A display device, characterized in that: It includes a liquid crystal panel and a backlight module, the backlight module includes the optical film structure according to any one of claims 1 to 11, the liquid crystal panel is arranged on the light-emitting side of the backlight module, the brightness ratio of the TCO horizontal viewing angle is between 1.32 and 1.71, and the brightness ratio of the TCO vertical viewing angle is between 1.53 and 1.73.

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