Backlight module

Abstract

The invention provides a backlight module. The backlight module comprises a back plate; the light source is arranged on the back plate; the first optical film is arranged on the back plate, the first optical film comprises a first upper surface and a first lower surface, the first upper surface is far away from the back plate compared with the first lower surface and is provided with a first prism structure, and at a first angle, a second angle and a third angle, the first prism structure is provided with a second prism structure. The backlight module is provided with a first brightness value A, a second brightness value B and a third brightness value C, and meets the following formula (1): | [(A / C)-(B / C)] x 100% | > = 10% (1), the third brightness value C is the maximum brightness value of the backlight module, and the first angle, the second angle and the third angle are different from one another.

Description

Technical Field

[0001] The invention relates to a backlight module, in particular to a backlight module containing a specially designed optical film. Background Art

[0002] With the rapid advancement of liquid crystal display (LCD) manufacturing technology and its advantages such as thinness, power saving and no radiation, LCDs are widely used in various electronic products such as tablet computers, notebook computers, digital cameras, digital camcorders, mobile phones, computer monitors and LCD TVs. LCDs require a backlight module to provide light to display images.

[0003] However, the current backlight module still has the disadvantages of low brightness contrast, narrow viewing angle, poor light extraction efficiency, etc. Therefore, it is necessary to provide a backlight module to improve the above-mentioned defects. Summary of the invention

[0004] The present invention provides a backlight module, characterized in that it comprises: a back plate; a light source disposed on the back plate; and a first optical film disposed on the back plate, wherein the first optical film comprises a first upper surface and a first lower surface, the first upper surface is farther from the back plate than the first lower surface and has a first prism structure, wherein at a first angle, a second angle and a third angle, the backlight module has a first brightness value A, a second brightness value B and a third brightness value C respectively, and satisfies the following formula (1):

[0005] ∣[(A / C)-(B / C)]x 100%∣≧10%(1)

[0006] The third brightness value C is the maximum brightness value of the backlight module, and the first angle, the second angle and the third angle are different from each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1A is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention;

[0008] Figure 1B is a three-dimensional schematic diagram of a backlight module according to an embodiment of the present invention;

[0009] Figure 2A is a schematic diagram of a first optical film according to an embodiment of the present invention;

[0010] Figure 2B is a schematic diagram of a second optical film according to an embodiment of the present invention;

[0011] Figure 2C and Figure 2Dis a schematic diagram of a portion of a second optical film according to an embodiment of the present invention;

[0012] Figure 2E is a schematic diagram of a third optical film according to an embodiment of the present invention;

[0013] Figure 3 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention;

[0014] Figure 4 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention;

[0015] Figure 5 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention;

[0016] Figure 6 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention;

[0017] Figure 7 A schematic diagram of measuring the brightness of a backlight module according to an embodiment of the present invention;

[0018] Figure 8 The figure is a brightness measurement result of a backlight module according to an embodiment of the present invention.

[0019] In the above drawings, the meanings of the reference numerals are as follows:

[0020] 1. Back panel;

[0021] 2. Light source;

[0022] 21. Light-emitting element;

[0023] 3. Light guide plate;

[0024] 4. The first optical film;

[0025] 4a, a first upper surface;

[0026] 4b, a first lower surface;

[0027] 41. The first prism structure;

[0028] 411, the first strip structure;

[0029] 42. Base material;

[0030] 5. Reflect the original;

[0031] 6. Second optical film;

[0032] 6a, second upper surface;

[0033] 6b, a second lower surface;

[0034] 61. Second prism structure;

[0035] 611, the second strip structure;

[0036] 62. Microstructure;

[0037] 63. Base material;

[0038] 7. The third optical film;

[0039] 7a, third upper surface;

[0040] 7b, third lower surface;

[0041] 71. The third prism structure;

[0042] 711, the third strip structure;

[0043] 72. Base material;

[0044] 8. Adhesive layer;

[0045] θ1, first vertex angle;

[0046] θ2, second vertex angle;

[0047] θ3, third vertex angle;

[0048] θa and θb, angle;

[0049] BL, backlight module;

[0050] F. Polarizer;

[0051] P, probe;

[0052] X, first direction;

[0053] Y, second direction;

[0054] Z, normal direction. DETAILED DESCRIPTION

[0055] The following describes the implementation of the present invention through specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified and changed in various ways according to different viewpoints and applications without departing from the spirit of the present invention.

[0056] It should be noted that, in this document, unless otherwise specified, "having an element" is not limited to having a single element, but may have one or more elements. Furthermore, the ordinal numbers used in the specification and claims, such as "first" and "second", to modify the elements of the claims, do not themselves imply or represent any previous ordinal numbers of the claimed elements, nor do they represent the order of one claimed element and another claimed element, or the order of the manufacturing method. The use of these ordinals is only used to make a claimed element with a certain name clearly distinguishable from another claimed element with the same name.

[0057] Certain words are used throughout the specification and the claims that follow to refer to specific components. It will be understood by those skilled in the art that electronic equipment manufacturers may refer to the same components by different names. It is not intended herein to distinguish between components that have the same function but different names. In the following specification and claims, the words "comprises", "contains", "has", etc. are open-ended words, and therefore should be interpreted as meaning "contains but is not limited to..." Therefore, when the terms "comprises", "contains" and / or "has" are used in the description of the present invention, they specify the presence of corresponding features, regions, steps, operations and / or components, but do not exclude the presence of one or more corresponding features, regions, steps, operations and / or components.

[0058] In the text, the terms "about", "approximately", "substantially", and "roughly" generally mean within 10%, within 5%, within 3%, within 2%, within 1%, or within 0.5% of a given value or range. The numbers given here are approximate numbers, that is, in the absence of specific instructions for "about", "approximately", "substantially", and "roughly", the meanings of "about", "approximately", "substantially", and "roughly" can still be implied. In addition, the terms "range is from a first value to a second value", "range is between a first value and a second value" mean that the range includes the first value, the second value, and other values ​​therebetween.

[0059] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It is understood that these terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with the background or context of the relevant technology and the present invention, and should not be interpreted in an idealized or overly formal manner unless specifically defined herein.

[0060] In addition, relative terms such as "below" or "bottom" and "above" or "top" may be used in the embodiments to describe the relative relationship of one element of the diagram to another element. It is understood that if the device of the diagram is turned upside down, the element described on the "below" side will become the element on the "above" side. When a corresponding component (such as a film layer or area) is referred to as "on another component", it can be directly on the other component, or there can be other components between the two. On the other hand, when a component is referred to as "directly on another component", there is no component between the two. In addition, when a component is referred to as "on another component", the two have an up-and-down relationship in the top-view direction, and this component can be above or below the other component, and this up-and-down relationship depends on the orientation of the device.

[0061] In the present invention, the angle can be measured by an optical microscope, and the angle can be measured by a cross-sectional image in an electron microscope, but the present invention is not limited thereto. In addition, there may be a certain error between the two values ​​or directions used for comparison. If the first value is equal to the second value, it implies that there may be an error of about 10% between the first value and the second value; if the first direction is perpendicular to the second direction, the angle between the first direction and the second direction may be between 80 degrees and 100 degrees; if the first direction is parallel to the second direction, the angle between the first direction and the second direction may be between 0 degrees and 10 degrees.

[0062] It should be noted that the technical solutions provided in the following different embodiments can be replaced, combined or mixed with each other to form another embodiment without violating the spirit of the present invention.

[0063] Figure 1A FIG. 4 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 1B FIG. 1 is a three-dimensional schematic diagram of a backlight module according to an embodiment of the present invention. For the convenience of explanation, Figure 1B Some structures are omitted.

[0064] In one embodiment of the present invention, Figure 1A and Figure 1B As shown, the backlight module may include: a back plate 1; a light source 2, which is arranged on the back plate 1; a light guide plate 3, which is arranged on the back plate 1 and opposite to the light source 2; and a first optical film 4, which is arranged on the back plate 1. The present invention can increase the brightness contrast of the backlight module, improve the light output or expand the light viewing angle by setting the first optical film 4, thereby achieving the advantages of improving the light output efficiency of the backlight module or improving the visual effect.

[0065] In the present invention, the material of the back plate 1 may include metal, alloy, polycarbonate (PC), polyimide (PI), polypropylene (PP), polyethyleneterephthalate (PET) or other plastic or polymer materials, or a combination of the foregoing, but the present invention is not limited thereto. In the present invention, the light source 2 may include a plurality of light emitting elements 21, and the plurality of light emitting elements 21 may be arranged, for example, along a first direction X. In some embodiments, the light source 2 may include a light emitting diode, and the light emitting diode may include, for example, an organic light emitting diode (OLED), a sub-millimeter light emitting diode (mini LED), a micro LED or a quantum dot light emitting diode (quantum dot LED, which may include QLED, QDLED), fluorescence, phosphor or other suitable materials, or a combination of the foregoing, but the present invention is not limited thereto.

[0066] The detailed structure of the first optical film 4 will be described in detail below.

[0067] Figure 2A FIG. 4 is a schematic diagram of a first optical film according to an embodiment of the present invention.

[0068] In one embodiment of the present invention, Figure 1A , Figure 1B and Figure 2A As shown, the first optical film 4 includes a first upper surface 4a and a first lower surface 4b opposite to the first upper surface 4a, wherein the first upper surface 4a is farther from the back plate 1 than the first lower surface 4b (for example, farther from the side of the back plate 1 parallel to the surface of the first optical film 4), and the first upper surface 4a has a first prism structure 41. The extension direction of the first prism structure 41 may be, for example, perpendicular to the first direction X. More specifically, the first prism structure 41 may have a plurality of first strip structures 411, and the plurality of first strip structures 411 may be arranged along the first direction X, and the "extension direction of the first prism structure 41" refers to the extension direction of the first strip structure 411 (for example, the second direction Y). The "perpendicular" means that the angle between the extension direction of the above-mentioned prism structure and the first direction X may be 80 degrees to 100 degrees (80°≦included angle≦100°). In one embodiment of the present invention, the first prism structure 41 has a first vertex angle θ1, and the first vertex angle θ1 can be 70 degrees to 110 degrees (70°≦θ1≦110°). For example, the first vertex angle θ1 can be 70°, 80°, 90°, 100°, 110°, or any value between the aforementioned values ​​or a numerical range consisting of any values.

[0069] In one embodiment of the present invention, Figure 2A As shown, the first optical film 4 includes a substrate 42, the substrate 42 has a multi-layer film structure, and the first prism structure 41 is arranged on the multi-layer film structure. In more detail, the multi-layer film structure can be composed of N layers of non-single refractive index films (N is a positive integer greater than 2), for example, the multi-layer film structure can be stacked by multiple layers of films with alternating refractive indices, and the first prism structure 41 can be directly arranged on the multi-layer film structure. Through the design of the multi-layer film structure, the substrate 42 of the first optical film 4 can be used to reflect the light source 2 (such as Figure 1A The polarized light provided by the backlight module increases the light output of the backlight module.

[0070] In the present invention, a CA410 color analyzer is used to test the brightness of the backlight module at different angles. It is found that at a first angle, a second angle, and a third angle, the backlight module has a first brightness value A, a second brightness value B, and a third brightness value C, respectively, and satisfies the following formula (1):

[0071] ∣[(A / C)-(B / C)]x 100%∣≧10%(1)

[0072] Wherein, the third brightness value C is the maximum brightness value of the backlight module, and the first angle, the second angle and the third angle are different from each other. Therefore, the backlight module of the present invention can have the advantages of a larger polarization state or a high brightness contrast, and can improve the light extraction efficiency of the backlight module. In one embodiment of the present invention, the value of |[(A / C)-(B / C)]x 100%| can be greater than or equal to 20% (i.e., ≧20%), for example, greater than or equal to 30% (i.e., ≧30%), greater than or equal to 40% (i.e., ≧40%), greater than or equal to 50% (i.e., ≧50%), greater than or equal to 60% (i.e., ≧60%), greater than or equal to 70% (i.e., ≧70%), greater than or equal to 80% (i.e., ≧80%), but the present invention is not limited thereto.

[0073] The following describes the method of measuring the backlight module using the CA410 color analyzer.

[0074] First, fix the polarizer F on the probe P of the CA410 color analyzer. In more detail, Figure 7As shown, the polarizer F is parallel to the backlight module BL to be measured, and is located between the probe P and the backlight module BL. Next, the probe P is placed perpendicular to the backlight module BL in preparation for measurement, wherein the "probe is perpendicular to the backlight module" may, for example, be to set the probe P along the normal direction Z of the backlight module BL. Afterwards, the probe P and the polarizer F are rotated and the brightness value of the backlight module BL is measured, wherein the starting position of the probe P is defined as 0 degrees, and one rotation of the probe P is 360 degrees. The "first angle, the second angle and the third angle" are the angles of rotation of the probe P, and the "first brightness value, the second brightness value and the third brightness value" are the brightness values ​​of the backlight module BL measured by the probe P at the corresponding rotation angles (such as the first angle, the second angle and the third angle). It should be noted that, as Figure 7 As shown, there should be as little gap as possible between the probe P and the polarizer F, and there should be as little gap as possible between the polarizer F and the backlight module BL to reduce the influence of ambient light on the measurement results. In another measurement state, if there is a gap between the probe P and the polarizer F, a light shielding sheet (not shown) can be set between the probe P and the polarizer F to reduce the influence of ambient light on the measurement results.

[0075] The above method Figure 1A As an example, the brightness of the backlight module is measured. After standardizing the brightness values ​​measured at each rotation angle, the following can be obtained: Figure 8 The standardized formula for the measurement result can be: (measured brightness value / maximum brightness value) x 100%. Figure 8 It can be found that when the probe is rotated about 90 degrees or 270 degrees, the backlight module has the maximum brightness value; when the probe is rotated about 0 degrees, 180 degrees or 360 degrees, the backlight module has the minimum brightness value. In addition, it can be found from the measurement results that Figure 1A The difference in polarization performance of the backlight module can reach about 80%. In other words, Figure 1A The brightness contrast of the backlight module can reach up to about 80%. Therefore, the backlight module of the present invention can have the advantages of a larger polarization state or a high brightness contrast.

[0076] In the present invention, the material of the first optical film 4 may include polycarbonate (PC), polyimide (PI), polyethylene terephthalate (PET), polyether polyol (POP), polymethylmethacrylate (PMMA), cycloolefin polymer (COP), rubber, glass, ultraviolet light curing glue (UV glue), optical clear adhesive (OCA), optical clear resin (OCR), acrylic resin, other suitable materials or combinations thereof, but the present invention is not limited thereto. In one embodiment of the present invention, the material of the first prism structure 41 may be UV glue, and the material of the substrate 42 may be PET; but the present invention is not limited thereto.

[0077] In one embodiment of the present invention, Figure 1A and Figure 1B As shown, the backlight module may include a reflective element 5, which is arranged on the back plate 1. More specifically, the reflective element 5 may be arranged between the light guide plate 3 and the back plate 1, and may be used to reflect the light provided by the light source 2, thereby improving the utilization rate of light or reducing light leakage. In the present invention, the material of the reflective element 5 is not particularly limited, for example, it may include metal, white ink, white tape, other reflective materials or a combination thereof. Among them, the metal may, for example, include gold, silver, copper, aluminum or a combination thereof, but the present invention is not limited thereto. The white ink may, for example, include white polyimide, resin or a combination thereof, but the present invention is not limited thereto. In addition, the reflective element 5 may include a single-layer or multi-layer film reflector.

[0078] Figure 2B FIG. 4 is a schematic diagram of a second optical film according to an embodiment of the present invention. Figure 2C and Figure 2D FIG. 4 is a schematic diagram of a portion of a second optical film according to an embodiment of the present invention.

[0079] In one embodiment of the present invention, Figure 1A , Figure 1B and Figure 2BAs shown, the backlight module may include a second optical film 6, which is disposed between the first optical film 4 and the back plate 1, wherein the second optical film 6 has a second prism structure 61. In more detail, the second optical film 6 includes a second upper surface 6a and a second lower surface 6b opposite to the second upper surface 6a, wherein the second upper surface 6a is farther away from the back plate 1 than the second lower surface 6b (or the second upper surface 6a is closer to the first optical film 4 than the second lower surface 6b), and the second lower surface 6b has a second prism structure 61. The extension direction of the second prism structure 61 may be, for example, perpendicular to the first direction X. More specifically, the second prism structure 61 may have a plurality of second strip structures 611, and the plurality of second strip structures 611 may be arranged along the first direction X, and the "extension direction of the second prism structure 61" refers to the extension direction of the second strip structure 611 (for example, the second direction Y). The "vertical" means that the angle between the extension direction of the above-mentioned prism structure 61 and the first direction X can be 80 degrees to 100 degrees (80°≦angle≦100°). In one embodiment of the present invention, the angle between the extension direction of the second prism structure 61 and the extension direction of the first prism structure 41 can be 0 degrees to 20 degrees (0°≦angle≦20°). In one embodiment of the present invention, the second prism structure 61 has a second vertex angle θ2, and the second vertex angle θ2 can be 80 degrees to 120 degrees (80°≦θ2≦120°). For example, the second vertex angle θ2 can be 80°, 90°, 100°, 110°, 120°, or any value between the aforementioned values ​​or a numerical range consisting of any values.

[0080] In one embodiment of the present invention, Figure 1B and Figure 2B As shown, the second upper surface 6a of the second optical film 6 may have a plurality of microstructures 62. The microstructures 62 have the effect of straightening the light or increasing the light output of the backlight module, thereby improving the light output efficiency of the backlight module. In one embodiment of the present invention, the microstructures 62 may be formed by, for example, a plurality of pyramid units arranged repeatedly, for example, in an array, but the present invention is not limited thereto. In one embodiment of the present invention, as shown in FIG. Figure 2C and Figure 2D As shown, Figure 2C is the projection of the microstructure 62 in the normal direction Z of the backlight module (for example, the projection in the XY plane), Figure 2D is the projection of the microstructure 62 in the second direction Y (for example, the projection in the XZ plane). When the microstructure 62 is a plurality of pyramid units, the angle θa between the projection of the microstructure 62 in the normal direction Z of the backlight module and the second direction Y may be 25 degrees to 65 degrees (25°≦θa≦65°), and the angle θb between the projection of the microstructure 62 in the second direction Y and the normal direction Z of the backlight module may be 45 degrees to 85 degrees (45°≦θb≦85°).

[0081] In one embodiment of the present invention, Figure 1A and Figure 2B As shown, the second optical film 6 includes a substrate 63, a second prism structure 61 is disposed on the substrate 63 and is disposed toward the back plate 1, and a microstructure 62 is disposed on the substrate 63 and is disposed toward the first optical film 4. The second prism structure 61 is disposed toward the back plate 1, which means that the second prism structure 61 is closer to the back plate 1 than the substrate 63, and the microstructure 62 is disposed toward the first optical film 4, which means that the microstructure 62 is closer to the first optical film 4 than the substrate 63. In another embodiment of the present invention, similar to Figure 1A The second optical film 6 may be a diffuser, for example, and thus the second prism structure 61 and the microstructure 62 may not be disposed on the substrate 63 , but the present invention is not limited thereto.

[0082] In the present invention, the second optical film 6 can be prepared using the same or different materials as the first optical film 4, and the materials of the second optical film 6 are as described for the first optical film 4, and will not be described again. In addition, the second prism structure 61, the microstructure 62, and the substrate 63 of the second optical film 6 can be prepared using the same or different materials, respectively. Therefore, in one embodiment of the present invention, when the second prism structure 61, the microstructure 62, and the substrate 63 of the second optical film 6 are prepared using the same material, the second optical film 6 can be integrally formed, but the present invention is not limited thereto.

[0083] Figure 2E FIG. 4 is a schematic diagram of a third optical film according to an embodiment of the present invention.

[0084] In one embodiment of the present invention, Figure 1A , Figure 1B and Figure 2EAs shown, the backlight module may selectively include a third optical film 7, which is disposed between the first optical film 4 and the back plate 1 (for example, it may be disposed between the first optical film 4 and the second optical film 6), and the third optical film 7 has a third prism structure 71. In more detail, the third optical film 7 includes a third upper surface 7a and a third lower surface 7b opposite to the third upper surface 7a, wherein the third upper surface 7a is farther from the back plate 1 than the third lower surface 7b (or the third upper surface 7a is closer to the first optical film 4 than the third lower surface 7b), and the third upper surface 7a has a third prism structure 71. The extension direction of the third prism structure 71 may be, for example, parallel to the first direction X. More specifically, the third prism structure 71 may have a plurality of third strip structures 711, and the plurality of third strip structures 711 may be arranged along a second direction Y perpendicular to the first direction X, and the "extension direction of the third prism structure 71" refers to the extension direction of the third strip structure 711 (for example, the first direction X). The term "parallel" means that the angle between the extension direction of the prism structure and the first direction X can be 0 to 20 degrees (0°≦angle≦20°). The term "perpendicular" means that the angle between the first direction X and the second direction Y can be 80 to 100 degrees (80°≦angle≦100°). In one embodiment of the present invention, the angle between the extension direction of the third prism structure 71 and the extension direction of the first prism structure 41 can be 80 to 100 degrees (80°≦angle≦100°). In one embodiment of the present invention, the third prism structure 71 has a third vertex angle θ3, and the third vertex angle θ3 can be 70 to 110 degrees (70°≦θ3≦110°). For example, the third vertex angle θ3 can be 70°, 80°, 90°, 100°, 110°, or any value between the aforementioned values ​​or a numerical range consisting of any values.

[0085] In one embodiment of the present invention, Figure 1A and Figure 2E As shown, the third optical film 7 includes a substrate 72, and the third prism structure 71 is arranged on the substrate 72. The substrate 72 can have a single-layer film or a multi-layer film structure design. In the present invention, the third optical film 7 can be prepared using the same or different materials as the first optical film 4 and / or the second optical film 6, and the material of the third optical film 7 is as described in the first optical film 4, which will not be repeated here. In addition, the third prism structure 71 and the substrate 72 of the third optical film 7 can be prepared using the same or different materials respectively. Therefore, in one embodiment of the present invention, when the third prism structure 71 and the substrate 72 of the third optical film 7 are the same material, the third optical film 7 can be integrally formed, but the present invention is not limited thereto.

[0086] In addition, in the present invention, the first optical film 4, the second optical film 6 and the third optical film 7 may have or not have haze, respectively, and the sum of the haze values ​​of the first optical film 4, the second optical film 6 and the third optical film 7 may be 100% to 160%. In one embodiment of the present invention, the first optical film 4, the second optical film 6 and the third optical film 7 may respectively include a substrate (e.g., substrate 42, substrate 63 and substrate 72) and a corresponding prism structure (e.g., first prism structure 41, second prism structure 61 and third prism structure 71), and the haze of the above optical film may be obtained by texturing, sandblasting or other suitable processes on the substrate and / or the prism structure, but the present invention is not limited thereto. In one embodiment of the present invention, the haze of the above optical film may be obtained by hard coating the substrate and / or applying diffusion particles to the material of the prism structure, but the present invention is not limited thereto.

[0087] Figure 3 FIG. 1 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 3 The backlight module and Figure 1A Similar, except for the following differences.

[0088] In one embodiment of the present invention, Figure 3 As shown, the backlight module may further include an adhesive layer 8, which is disposed between the first optical film 4 and the third optical film 7. In more detail, the adhesive layer 8 may contact the first lower surface 4b of the first optical film 4 and the third upper surface 7a of the third optical film 7, so that the first optical film 4 and the third optical film 7 are bonded to each other to form an optical film set. In this way, the relative position offset between the optical films can be reduced, the assembly qualification rate of the backlight module can be improved, or the process steps can be simplified. In addition, in another embodiment of the present invention, although not shown in the figure, the adhesive layer 8 can also be disposed between the second optical film 6 and the third optical film 7, so that the second optical film 6 and the third optical film 7 are bonded to each other through the adhesive layer 8 to form another optical film set. In another embodiment of the present invention, similar to Figure 3 The second optical film 6 may be a diffuser, for example, and thus the second prism structure 61 and the microstructure 62 may not be disposed on the substrate 63 , but the present invention is not limited thereto.

[0089] In one embodiment of the present invention, the adhesive layer 8 may include a light-curing adhesive, a heat-curing adhesive, a light-heat-curing adhesive, a moisture-curing adhesive, an adhesive tape, other suitable materials, or a combination thereof, but the present invention is not limited thereto. In one embodiment of the present invention, the material of the adhesive layer 8 may include polyvinyl butyral (PVB), ethylene-vinyl acetate (EVA), thermoplastic polyurethane (TPU), optical clear adhesive (OCA), optical clear resin (OCR), other suitable materials, or a combination thereof, but the present invention is not limited thereto.

[0090] In this embodiment, the features of the first optical film 4 , the second optical film 6 , the third optical film 7 and other elements are as described above and will not be described in detail herein.

[0091] Figure 4 FIG. 1 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 4 The backlight module and Figure 1A Similar, except for the following differences.

[0092] In one embodiment of the present invention, Figure 4 As shown, the second optical film 6 of the backlight module may have a second prism structure 61, but does not have a microstructure 62 (eg, Figure 2B ), wherein the second prism structure 61 is disposed on the substrate 63. In more detail, the second optical film 6 comprises a second upper surface 6a and a second lower surface 6b opposite to the second upper surface 6a, wherein the second upper surface 6a is farther from the back plate 1 than the second lower surface 6b (or the second upper surface 6a is closer to the first optical film 4 than the second lower surface 6b), the second lower surface 6b has the second prism structure 61, and the second upper surface 6a can be a plane without having Figure 2B In another embodiment of the present invention, similar to the microstructure 62 shown in FIG. Figure 4 The second optical film 6 may be, for example, a diffuser, and thus the second prism structure 61 may not be disposed on the substrate 63 , but the present invention is not limited thereto.

[0093] In this embodiment, except for some differences of the second optical film 6 mentioned above, the features of the first optical film 4 , the second optical film 6 , the third optical film 7 and other components are as described above and will not be repeated here.

[0094] Figure 5 FIG. 1 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 5 The backlight module and Figure 1A Similar, except for the following differences.

[0095] In one embodiment of the present invention, Figure 5 As shown, the backlight module may include: a first optical film 4, which is disposed on the back plate 1; and a second optical film 6, which is disposed between the first optical film 4 and the back plate 1. The first optical film 4 includes a first upper surface 4a and a first lower surface 4b opposite to the first upper surface 4a, wherein the first upper surface 4a is farther from the back plate 1 than the first lower surface 4b (for example, away from the side of the back plate 1 parallel to the surface of the first optical film 4), and the first upper surface 4a has a first prism structure 41, and the extension direction of the first prism structure 41 may be, for example, parallel to the first direction X. The second optical film 6 includes a second upper surface 6a and a second lower surface 6b opposite to the second upper surface 6a, wherein the second upper surface 6a is farther from the back plate 1 than the second lower surface 6b (or the second upper surface 6a is adjacent to the first optical film 4 than the second lower surface 6b), and the second upper surface 6a has a second prism structure 61, and the extension direction of the second prism structure 61 may be, for example, parallel to the first direction X. The "parallel" means that the angle between the extension direction of the prism structure and the first direction X can be 0 to 20 degrees (0°≦angle≦20°). In one embodiment of the present invention, the angle between the extension direction of the second prism structure 61 and the extension direction of the first prism structure 41 can be 0 to 20 degrees (0°≦angle≦20°). In one embodiment of the present invention, the second prism structure 61 can be disposed on the substrate 63, and the second lower surface 6b of the second optical film 6 can be a plane.

[0096] In this embodiment, the backlight module may not be provided with the third optical film 7 (eg Figure 1A In addition, except for the partial differences between the first optical film 4 and the second optical film 6, the features of the first optical film 4, the second optical film 6 and other components are as described above and will not be repeated here.

[0097] Figure 6 FIG. 1 is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 6 The backlight module and Figure 1A Similar, except for the following differences.

[0098] In one embodiment of the present invention, Figure 6 As shown, the backlight module can be a straight-down backlight module. More specifically, the backlight module can include: a back panel 1; a light source 2, disposed on the back panel 1; a first optical film 4, disposed on the back panel 1; and a third optical film 7, disposed between the first optical film 4 and the back panel 1.

[0099] In one embodiment of the present invention, Figure 6As shown, the first optical film 4 includes a first upper surface 4a and a first lower surface 4b opposite to the first upper surface 4a, wherein the first upper surface 4a is farther from the back plate 1 than the first lower surface 4b, and the first upper surface 4a has a first prism structure 41, and the extension direction of the first prism structure 41 can be, for example, perpendicular to the first direction X. The third optical film 7 includes a third upper surface 7a and a third lower surface 7b opposite to the third upper surface 7a, wherein the third upper surface 7a is farther from the back plate 1 than the third lower surface 7b, and the third lower surface 7b has a third prism structure 71, and the extension direction of the third prism structure 71 can be, for example, parallel to the first direction X. The "perpendicular" means that the angle between the extension direction of the prism structure and the first direction X can be 80 degrees to 100 degrees (80°≦angle≦100°). The "parallel" means that the angle between the extension direction of the prism structure and the first direction X can be 0 degrees to 20 degrees (0°≦angle≦20°).

[0100] In another embodiment of the present invention, although not shown in the figure, the extension direction of the first prism structure 41 may be, for example, parallel to the first direction X, and the extension direction of the third prism structure 71 may be, for example, perpendicular to the first direction X. By designing the extension direction of the first prism structure 41 to be perpendicular to the extension direction of the third prism structure 71, the light output efficiency of the backlight module can be improved or the visual effect can be improved. Therefore, in one embodiment of the present invention, the angle between the extension direction of the third prism structure 71 and the extension direction of the first prism structure 41 may be 80 degrees to 100 degrees (80°≦angle≦100°).

[0101] In this embodiment, except for some differences of the third optical film 7 mentioned above, the features of the first optical film 4 , the third optical film 7 and other components are as described above and will not be repeated here.

[0102] The backlight module of the present invention can be applied to various display panels that require a backlight source to form a display device. The display panel can be, for example, a flexible display panel, a touch display panel, a curved display panel, or a tiled display panel, but the present invention is not limited thereto. The display device can be, for example, a display, a mobile phone, a notebook computer, a video camera, a camera, a music player, a mobile navigation device, a television, or other electronic device that needs to display an image, but the present invention is not limited thereto.

[0103] The above specific embodiments should be interpreted as merely illustrative and not limiting the rest of the present invention in any way. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A backlight module, characterized in that: Include: a back plate; a light source disposed on the back panel; and a first optical film disposed on the back plate, wherein the first optical film comprises a first upper surface and a first lower surface, wherein the first upper surface is farther from the back plate than the first lower surface and has a first prism structure, Wherein, at a first angle, a second angle and a third angle, the backlight module has a first brightness value A, a second brightness value B and a third brightness value C respectively, and satisfies the following formula (1): ∣[(A / C)-(B / C)]x 100%∣≧10%(1) The third brightness value C is the maximum brightness value of the backlight module, and the first angle, the second angle and the third angle are different from each other.

2. The backlight module according to claim 1, characterized in that: The first optical film comprises a substrate having a multi-layer film structure, and the first prism structure is arranged on the multi-layer film structure.

3. The backlight module according to claim 1, characterized in that: It also includes a second optical film, which is arranged between the first optical film and the back plate, wherein the second optical film has a second prism structure, and the angle between the extension direction of the second prism structure and the extension direction of the first prism structure is 0 degree to 20 degrees.

4. The backlight module according to claim 3, characterized in that: The second optical film includes a second upper surface and a second lower surface opposite to the second upper surface, wherein the second upper surface is farther from the back plate than the second lower surface, and the second lower surface has the second prism structure.

5. The backlight module according to claim 4, characterized in that: It also includes a third optical film, which is arranged between the first optical film and the second optical film, wherein the third optical film has a third prism structure, and the angle between the extension direction of the third prism structure and the extension direction of the first prism structure is 80 degrees to 100 degrees.

6. The backlight module according to claim 4, characterized in that: The second upper surface has a plurality of microstructures.

7. The backlight module according to claim 3, characterized in that: The second optical film includes a second upper surface and a second lower surface opposite to the second upper surface, wherein the second upper surface is farther from the back plate than the second lower surface, and the second upper surface has the second prism structure.

8. The backlight module according to claim 1, characterized in that: It also includes a third optical film, which is arranged between the first optical film and the back plate, wherein the third optical film has a third prism structure, and the angle between the extension direction of the third prism structure and the extension direction of the first prism structure is 80 degrees to 100 degrees.

9. The backlight module according to claim 8, characterized in that: The third optical film includes a third upper surface and a third lower surface opposite to the third upper surface, wherein the third upper surface is farther from the back plate than the third lower surface, and the third upper surface has the third prism structure.

10. The backlight module according to claim 8, characterized in that: The invention also comprises an adhesive layer which is arranged between the first optical film and the third optical film.

11. The backlight module according to claim 8, characterized in that: The third optical film includes a third upper surface and a third lower surface opposite to the third upper surface, wherein the third upper surface is farther from the back plate than the third lower surface, and the third lower surface has the third prism structure.

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