Backlight module and display apparatus

Abstract

The present disclosure discloses a backlight module and a display apparatus, which are used for improving the brightness uniformity of the backlight module. The backlight module comprises a light source assembly, a first prism structure, and a second prism structure. The first prism structure and the second prism structure each comprise a substrate and a prism layer. The prism layer comprises multiple prisms. In at least one of the first prism structure and the second prism structure, all of the prisms in the prism layer are divided into multiple prism repeating units, and each prism repeating unit comprises multiple prisms. The distance from a valley line formed by connecting side faces of any two adjacent prisms in a prism repeating unit to the substrate is a first distance, the distance from a valley line formed by connecting side faces of adjacent prisms separately located in two prism repeating units to the substrate is a second distance, and the first distance is larger than the second distance. An included angle between the direction of extension of the prisms in the first prism structure and the direction of extension of the prisms in the second prism structure is greater than or equal to 40°, and less than or equal to 65°.

Description

Backlight module and display device

[0001] Cross Reference to Related Applications

[0002] The present disclosure claims priority to the Chinese patent application No. 202410671490.1, filed on May 28, 2024, and entitled “Backlight module and display device”, the entire content of which is incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of display, and in particular, to a backlight module and a display device. BACKGROUND

[0004] Display has been widely applied to various fields and is closely related to our work, study and life. In the prior art, the backlight module of the display usually needs to be provided with double-layer prism sheets to improve light utilization, but the provision of the double-layer prism sheets has the problem of poor viewing angle brightness uniformity, which affects the display effect. SUMMARY

[0005] The embodiments of the present disclosure provide a backlight module and a display device to improve the brightness uniformity of the backlight module.

[0006] The backlight module provided by the embodiments of the present disclosure comprises: a light source assembly, a first prism structure located on the light emitting side of the light source assembly, and a second prism structure located on the side of the first prism structure away from the light source assembly.

[0007] The first prism structure and the second prism structure each comprise: a substrate, and a prism layer located on the side of the substrate away from the light source assembly; the prism layer comprises a plurality of prisms, and the plurality of prisms are arranged in sequence along a direction intersecting with the extension direction of the prisms.

[0008] In at least one of the first prism structure and the second prism structure, all the prisms in the prism layer are divided into a plurality of prism repeating units, and each prism repeating unit comprises a plurality of prisms; the distance from the valley line formed by the side surfaces of any two adjacent prisms in the prism repeating unit to the substrate is a first distance, and the distance from the valley line formed by the side surfaces of the adjacent prisms located in two adjacent prism repeating units to the substrate is a second distance, and the first distance is greater than the second distance.

[0009] The angle between the extension direction of the prisms in the first prism structure and the extension direction of the prisms in the second prism structure is greater than or equal to 40° and less than or equal to 65°.

[0010] In some embodiments, the thickness of all the prisms in the prism layer in the direction perpendicular to the substrate is equal.

[0011] In some embodiments, in a prism layer including prism repeating units, the distance between the ridges of two adjacent prisms in a prism repeating unit is a third distance, and the distance between the ridges of two adjacent prisms located in different prism repeating units is a fourth distance.

[0012] The third distance is greater than or equal to 27 micrometers and less than or equal to 47 micrometers, the fourth distance is greater than or equal to 37 micrometers and less than or equal to 57 micrometers, and the third distance is less than the fourth distance.

[0013] In some embodiments, the first prism structure includes: a first substrate, and a plurality of repeating first prism units arranged on the side of the first substrate away from the light source assembly. The repeating first prism unit includes: a plurality of first prisms extending along a first direction; the first direction intersects with a second direction, and the second direction is the horizontal direction of the backlight module.

[0014] The second prism structure includes: a second base, and a plurality of repeating second prism units located on the side of the second base away from the first prism structure and arranged along a third direction; the repeating second prism units include: a plurality of second prisms arranged along a third direction and extending along a fourth direction; the third direction is perpendicular to the fourth direction, and the first direction intersects both the third and fourth directions;

[0015] The angle between the second direction and the second direction is greater than or equal to 60° and less than 90°, and the angle between the fourth direction and the second direction is greater than or equal to 5° and less than or equal to 20°.

[0016] In some embodiments, the angle between the second direction and the first direction is greater than or equal to 70° and less than or equal to 80°, and the angle between the fourth direction and the second direction is greater than or equal to 12° and less than or equal to 17°.

[0017] In some embodiments, the angle between the first direction and the fourth direction is greater than or equal to 50° and less than or equal to 60°.

[0018] In some embodiments, the first prism structure further includes a first haze layer located on the side of the first substrate opposite to the first prism repeating unit.

[0019] In some embodiments, the haze of the first haze layer is greater than or equal to 25% and less than or equal to 60%.

[0020] In some embodiments, the second prism structure further includes a second haze layer located on the side of the second substrate opposite to the second prism repeating unit.

[0021] In some embodiments, the haze of the second haze layer is greater than or equal to 7% and less than or equal to 17%.

[0022] In some embodiments, the first prism has a first apex angle corresponding to the ridge line along a cross section perpendicular to the first direction; the second prism has a second apex angle corresponding to the ridge line along a cross section of the third direction.

[0023] The first vertex angle is greater than or equal to 91° and less than or equal to 94°, or the first vertex angle is a rounded corner and the central angle corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°;

[0024] The second vertex angle is greater than or equal to 91° and less than or equal to 94°, or the second vertex angle is a rounded corner and the central angle corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°.

[0025] In some embodiments, the first prism structure includes a first prism repeating unit, and the second prism structure includes a second prism repeating unit.

[0026] The number of first prisms in the first prism repeating unit is equal to the number of second prisms in the second prism repeating unit.

[0027] In some embodiments, the refractive index of the prism layer is greater than or equal to 1.54 and less than or equal to 1.60.

[0028] In some embodiments, the backlight module further includes a diffusion film located on the side of the first prism structure opposite to the second prism structure.

[0029] This disclosure provides a display device, which includes a backlight module and a display panel located on the light-emitting side of the backlight module.

[0030] The backlight module and display device provided in this disclosure, in at least one of the first prism structure and the second prism structure, the distance from the valley line between adjacent prisms in the repeating unit to the substrate is different from the distance from the valley line between two prisms in the adjacent repeating unit to the substrate. That is, the valley lines between prisms in the prism layer are located on different planes. Compared with conventional prisms where the valley lines between prisms are on the same plane, this can improve the center brightness and the uniformity of brightness from different viewing angles. When the backlight module is applied to a display product, it avoids the defect of uneven brightness and asymmetry between the left and right sides of the display product, thus improving the display effect. Furthermore, the angle α5 between the extension direction of the prism in the first prism structure and the extension direction of the prism in the second prism structure is greater than or equal to 50° and less than or equal to 60°. Compared with the case where the extension directions of the prisms in the upper and lower prism structures are perpendicular, this can further improve the brightness uniformity. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this disclosure, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 is a schematic diagram of a backlight module provided by related technologies;

[0033] Figure 2 shows the full-view brightness diagram of a backlight module provided by related technologies;

[0034] Figure 3 is a schematic diagram of the structure of a backlight module provided in an embodiment of this disclosure;

[0035] Figure 4 is a cross-sectional view along AA' in Figure 3 provided by an embodiment of this disclosure;

[0036] Figure 5 is a cross-sectional view along BB' in Figure 3 provided by an embodiment of this disclosure;

[0037] Figure 6 is a schematic diagram of a first prism structure provided in an embodiment of this disclosure;

[0038] Figure 7 is a schematic diagram of a second prism structure provided in an embodiment of this disclosure;

[0039] Figure 8 is an optical path diagram of a light incident angle of 0° provided in an embodiment of this disclosure;

[0040] Figure 9 is an optical path diagram of a light incident angle of 10° provided in an embodiment of this disclosure;

[0041] Figure 10 is an optical path diagram of a light incident angle of 20° provided in an embodiment of this disclosure;

[0042] Figure 11 is an optical path diagram of a light incident angle of 30° provided in an embodiment of this disclosure;

[0043] Figure 12 is an optical path diagram of a light incident angle of 40° provided in an embodiment of this disclosure;

[0044] Figure 13 is an optical path diagram of a light incident angle of 50° provided in an embodiment of this disclosure;

[0045] Figure 14 is a schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0046] Figure 15 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0047] Figure 16 is a full-view brightness diagram of a backlight module provided in an embodiment of this disclosure;

[0048] Figure 17 is a comparison diagram of horizontal viewing angle brightness curves provided in an embodiment of this disclosure;

[0049] Figure 18 is a full-view brightness diagram of another backlight module provided in an embodiment of this disclosure;

[0050] Figure 19 is a full-view brightness diagram of another backlight module provided in an embodiment of this disclosure;

[0051] Figure 20 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0052] Figure 21 is a schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0053] Figure 22 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0054] Figure 23 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0055] Figure 24 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0056] Figure 25 is a structural schematic diagram of another backlight module provided in an embodiment of this disclosure;

[0057] Figure 26 is a schematic diagram of the structure of a display device provided in an embodiment of this disclosure. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Furthermore, the embodiments and features in the embodiments of this disclosure can be combined with each other without conflict. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0059] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as “comprising” or “including” mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect.

[0060] It should be noted that the dimensions and shapes of the figures in the accompanying drawings do not reflect actual proportions and are intended only to illustrate the content of this disclosure. Furthermore, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0061] In related technologies, as shown in Figure 1, the backlight module of a display product needs to be equipped with two layers of prism sheets 9. The angle between the extension direction of the prism in the upper prism sheet and the horizontal direction X is 0°, and the angle between the extension direction of the prism in the lower prism sheet and the horizontal direction X is 90°. In each prism sheet 9, the valley line 8 formed by the side surfaces of any adjacent prisms 6 is located on the same plane. The full-view brightness diagram of the backlight module including the double-layer prism sheet 9 shown in Figure 1 is shown in Figure 2. The center brightness is not high, and the brightness on the left and right is uneven. When the backlight module is applied to a display product, it will cause the left and right sides of the display product to be dark and asymmetrical, which will affect the display effect.

[0062] This disclosure provides a backlight module, as shown in Figures 3, 4 and 5. The backlight module includes: a light source assembly 1, a first prism structure 2 located on the light-emitting side of the light source assembly 1, and a second prism structure 3 located on the side of the first prism structure 2 facing away from the light source assembly 1.

[0063] Both the first prism structure 2 and the second prism structure 3 include: a substrate 4, and a prism layer 5 located on the side of the substrate 4 away from the light source assembly 1; the prism layer 5 includes a plurality of prisms 6, which are arranged sequentially along a direction intersecting its extension direction.

[0064] In at least one of the first prism structure 2 and the second prism structure 3, all prisms 6 in the prism layer 5 are divided into multiple prism repeating units 7, and each prism repeating unit 7 includes multiple prisms 6; the distance from the valley line 8 formed by the side surfaces of any two adjacent prisms 6 in the prism repeating unit 7 to the substrate 4 is the first distance h1, and the distance from the valley line 8 formed by the side surfaces of adjacent prisms 6 in two prism repeating units 7 to the substrate 4 is the second distance h2, and the first distance h1 is greater than the second distance h2.

[0065] The angle a5 between the extension direction of prism 6 in the first prism structure 2 and the extension direction of prism 6 in the second prism structure 3 is greater than or equal to 40° and less than or equal to 65°.

[0066] It should be noted that Figure 3 is a projection of the first prism structure 2 and the second prism structure 3 onto the base 4, and the three-dimensional views of the first prism structure 2 and the second prism structure 3 are shown in Figure 6 and Figure 7, respectively; Figure 4 is a cross-sectional view along AA' in Figure 3, and Figure 5 is a cross-sectional view along BB' in Figure 3.

[0067] It should be noted that, as shown in Figure 4, the junction of the side surface 13 of the prism 6 corresponds to the ridge line 10 of the prism 6; the thickness of the prism 6 in the direction perpendicular to the base 4 is the distance between the highest point of the prism 6, i.e., the ridge line 10, and the base 4.

[0068] The backlight module provided in this embodiment, in at least one of the first prism structure and the second prism structure, has a different distance from the valley line between adjacent prisms in the repeating unit to the substrate compared to the distance from the valley line between two prisms in the adjacent repeating unit. That is, the valley lines between prisms in the prism layer are located on different planes. Compared to conventional prisms where the valley lines between prisms are on the same plane, this improves the center brightness and brightness uniformity across different viewing angles. When the backlight module is applied to a display product, it avoids the undesirable asymmetry of dark left and right sides of the display, thus improving the display effect. Furthermore, the angle a5 between the extension directions of the prisms in the first prism structure and the extension directions of the prisms in the second prism structure is greater than or equal to 40° and less than or equal to 65°. Compared to the case where the extension directions of the prisms in the upper and lower prism structures are perpendicular, this improves brightness uniformity.

[0069] In some embodiments, as shown in FIG14, all prisms 6 in the prism layer 5 have the same thickness in the direction perpendicular to the substrate 4.

[0070] The backlight module provided in this embodiment has all prisms in the prism layer having the same thickness in the direction perpendicular to the substrate. This simplifies the manufacturing difficulty of the prism layer, makes it easier to mass-produce the prism structure, and also helps to improve the uniformity of the light output brightness of the prism layer.

[0071] In some embodiments, the substrate material is polyethylene terephthalate (PET), and the prism layer material is UV-curable adhesive; in specific implementations, UV-curable adhesive is provided on one side of the PET, and UV curing is performed to imprint the pattern of the prism layer.

[0072] Alternatively, in some embodiments, the substrate and the prism layer are an integral structure.

[0073] It should be noted that when the backlight module is applied to the backlight module of a display product, the display product has a fixed horizontal and vertical direction. The horizontal direction is parallel to the direction in which human eyes are aligned. For example, in Figure 3, the second direction X corresponds to the horizontal direction of the display product when the backlight module is applied to the display product, and the fifth direction Y in Figure 3 corresponds to the vertical direction of the display product when the backlight module is applied to the display product. When the first prism structure and the second prism structure are projected into a rectangular shape in the direction perpendicular to the base, and the sides of the rectangle are parallel to the horizontal and vertical directions respectively, the second direction X is also the extension direction of the edge of the prism structure.

[0074] It should be noted that one of the certification standards for display products is TCO. TCO requires the display product to meet the following requirements for viewing angle brightness uniformity: (1) Horizontal TCO of the display product: [(L max +30° / L min+30° )+(L max-30° / L min-30° )] / 2≤1.73; where, L max+30° L is the luminance value corresponding to the viewing angle with maximum luminance in the horizontal direction + 30°. min+30° L represents the luminance value corresponding to a viewing angle with minimum luminance in the horizontal direction plus 30°. max-30° L represents the luminance value corresponding to a viewing angle of 30° below the viewing angle with maximum luminance in the horizontal direction. min-30° (2) Vertical TCO of the display product: L max+15° / L min+15° ≤1.73, L max-15° / L min-15° ≤1.73; where L max+15° L is the luminance value corresponding to the viewing angle with the maximum luminance in the vertical direction + 15°. min+15° L represents the luminance value corresponding to the viewing angle with the lowest luminance in the vertical direction plus 15°. max-15° L represents the luminance value corresponding to the viewing angle with maximum luminance in the vertical direction minus 15°. min-15° This represents the brightness value corresponding to the viewing angle with the lowest brightness in the vertical direction, which is -15°.

[0075] Related technologies include the application of double-prism backlight modules in display products, which cannot meet the TCO requirements for viewing angle uniformity of display product brightness.

[0076] The principle that a greater first distance than a second distance can improve brightness is briefly explained below. In related technologies, the valley lines between prisms are located on the same plane, so it can be assumed that there is no overlap between prisms. However, when the valley lines between prisms in a prism layer are located on different planes, the first distance is greater than the second distance. That is, the distance from the valley line formed by the side surfaces of any two adjacent prisms in a prism repeating unit to the substrate must be greater than 0. It can be assumed that two adjacent prisms in a prism repeating unit overlap, while there is no overlap between adjacent prisms located in two prism repeating units respectively. Figures 8, 9, 10, 11, 12, and 13 are the light path diagrams with incident angles of 0°, 10°, 20°, 30°, 40°, and 50°, respectively. D1 corresponds to a non-overlapping prism, and D2 corresponds to an overlapping prism. When light enters the overlapping part, it changes the exit angle. The overlapping part of 0° to 20° exits earlier, and the light converges; the light of 20° to 40° diverges towards a wider angle. The backlight module provided in this embodiment features a prism overlapping design in the prism repeating unit, where the valley lines between prisms in the prism layer are located on different planes. This design allows light to converge at the vertical viewing angle and diverge at the horizontal viewing angle to maximize brightness gain under TCO conditions.

[0077] It should be noted that the 0-grayscale brightness L0 is directly proportional to the scattering coefficient. When the incident light is essentially perpendicular to the display product, the scattering coefficient is small, and the L0 brightness is low. When the light is incident from a side direction perpendicular to the display product, the scattering coefficient increases, and the L0 brightness increases. Therefore, the higher the collimation of the light emitted from the backlight module, the smaller the scattering, the lower the L0 brightness, and the higher the contrast of the displayed product. The backlight module provided in this embodiment features a prism overlapping design in the prism repeating unit, meaning that the valley lines between the prisms in the prism layer are located on different planes. This allows the light to converge at the vertical viewing angle, which is beneficial for improving contrast.

[0078] It should be noted that the plane of the first prism structure is parallel to the light-emitting plane of the light source assembly, and the light emitted from the light-emitting surface of the light source assembly reaches the first prism structure and the second prism structure in sequence.

[0079] It should be noted that the light source assembly can be a direct-lit light source assembly or a side-lit light source assembly.

[0080] In some embodiments, as shown in FIG14, the backlight module includes a diffusion film 17 located between the light source assembly 1 and the first prism structure 2.

[0081] In a specific implementation, as shown in Figure 14, the side-lit light source assembly 1 may include at least one lamp strip 101, a first reflective sheet 103 stacked together, and a light guide plate 104. A diffusion film 17 is located on the side of the light guide plate 104 facing away from the first reflective sheet 103, and the lamp strip 101 is located on one side of the light guide plate 104 along its thickness direction, i.e., the lamp strip 101 faces the side of the light guide plate 104. The light source assembly 1 may also include: a first substrate 106 and a plurality of second reflective sheets 102; the lamp strip 101 is disposed on the side of the first substrate 106 facing the light guide plate 104, and the plurality of second reflective sheets 102 are respectively disposed on the side of the light guide plate 104. The lamp strip may include, for example, a plurality of LEDs.

[0082] In a specific implementation, as shown in Figure 15, the direct-lit light source assembly 1 may include a matrix light source 107 and a reflective sheet 108 stacked on the light-emitting side of the matrix light source 107; a diffuser film 17 is located on the side of the reflective sheet 108 facing away from the matrix light source 107; for example, the matrix light source 107 includes a plurality of LEDs 1071 arranged in an array. The reflective sheet includes openings that are directly opposite the positions of the LEDs in the matrix light source.

[0083] In practical implementation, the LEDs in the light strip and the LEDs in the matrix light source can be light-emitting diodes (LEDs), such as miniature LEDs (Mini LED, Micro LED, etc.).

[0084] In some embodiments, the backlight module further includes a first polarizer located on the side of the second prism structure opposite to the first prism structure. When the backlight module is applied to a display product, the first polarizer serves as the lower polarizer of the display product.

[0085] In some embodiments, as shown in FIG4, the prism layer 5 of the first prism structure 2 and the second prism structure 3 both include a plurality of prism repeating units 7, and the distance from the valley line 8 formed by the side surfaces of any two adjacent prisms 6 in the prism repeating unit 7 to the substrate 4 is a first distance h1, and the distance from the valley line 8 formed by the side surfaces of adjacent prisms 6 in the two prism repeating units 7 to the substrate 4 is a second distance h2, wherein the first distance h1 is greater than the second distance h2.

[0086] Simulations were performed on the backlight module provided in this embodiment. With the valley lines between the prisms in the prism layers of the two prism structures located on different planes, the full-view brightness diagram of the backlight module is shown in Figure 16. Compared with the full-view brightness diagram of the backlight module of the related technology shown in Figure 2, the center brightness is improved, and the brightness uniformity is also improved. Figure 17 shows the horizontal viewing angle brightness curves of the backlight module provided in this embodiment and the backlight module of the related technology. C1 is the horizontal viewing angle brightness curve of the backlight module provided in this embodiment, and C2 is the horizontal viewing angle brightness curve of the backlight module of the related technology. It can be more intuitively seen that the center brightness of the backlight module provided in this embodiment is improved, and the symmetry of curve C1 is better than that of curve C2, meaning that the brightness uniformity of the backlight module provided in this embodiment is improved compared to the related technology.

[0087] The backlight module provided in this embodiment has two prism structures in which the valley lines between the prisms in the prism layers are located on different planes. Therefore, compared with conventional prisms where the valley lines between the prisms are located on the same plane, both the first prism structure and the second prism structure can improve the center brightness. This can further improve the center brightness of the backlight module and the brightness uniformity of different viewing angles. When the backlight module is applied to display products, it avoids the defect of uneven brightness and asymmetry between the left and right sides of the display product, thus improving the display effect.

[0088] In some embodiments, as shown in FIG4, the first prism structure 2 includes: a first base 401, a plurality of first prism repeating units 701 located on the side of the first base 401 away from the light source assembly 1 and arranged along a direction perpendicular to the first direction Y1, the first prism repeating unit 701 including: a plurality of first prisms 601 arranged along a direction perpendicular to the first direction Y1 and extending along the first direction Y1; the second direction X intersects the first direction Y1;

[0089] The second prism structure 3 includes: a second base 402, and a plurality of second prism repeating units 702 located on the side of the second base 402 away from the first prism structure 2 and arranged along a third direction X1; the second prism repeating unit 702 includes: a plurality of second prisms 602 arranged along a third direction X1 and extending along a fourth direction Y2; the third direction X1 is perpendicular to the fourth direction Y2, the second direction X intersects both the third direction X1 and the fourth direction Y2, and the first direction Y1 intersects both the third direction X1 and the fourth direction Y2.

[0090] In some embodiments, the backlight module provided in this disclosure does not include a brightness enhancement film on the side of the second prism structure opposite to the first prism structure.

[0091] It should be noted that the backlight modules of related technologies require a brightness enhancement film to be placed above the double-layer prism structure to increase the light output brightness of the backlight module. However, the backlight module provided in this disclosure has valleys between prisms in the prism layers of the two prism structures located on different planes, which can improve the light output brightness of the backlight module. Therefore, the backlight module does not need to be equipped with a brightness enhancement film, which can reduce the thickness of the backlight module and save costs.

[0092] In some embodiments, as shown in FIG4, a plurality of prisms 6 in the prism layer 5 are arranged in close proximity, that is, the side surfaces of adjacent prisms 6 are connected, and a valley line 8 is formed at the point where the side surfaces of adjacent prisms 6 are connected, which is in the same direction as the extension of the prism 6.

[0093] In some embodiments, as shown in FIG4, in the prism layer 5 including the prism repeating unit 7, the distance between the ridges of two adjacent prisms 6 in the prism repeating unit 7 is the third distance P1, and the distance between the ridges of two adjacent prisms 6 located in different prism repeating units 7 is the fourth distance P2.

[0094] The third distance P1 is greater than or equal to 27 micrometers and less than or equal to 47 micrometers, the fourth distance P2 is greater than or equal to 37 micrometers and less than or equal to 57 micrometers, and the third distance P1 is less than the fourth distance P2.

[0095] In some embodiments, the difference between the second distance h2 and the first distance h1 is, for example, 10 micrometers.

[0096] It should be noted that if the third distance P1 is less than 27 micrometers, the light output brightness of the prism structure will be insufficient, failing to meet the Total Cost of Ownership (TCO) requirements. When the fourth distance P2 is greater than 57 micrometers, the backlight module is prone to moiré patterns when applied to display products, affecting the display effect. Therefore, while ensuring that the third distance P1 is less than the fourth distance P2, a third distance P1 greater than or equal to 27 micrometers and less than or equal to 47 micrometers, and a fourth distance P2 greater than or equal to 37 micrometers and less than or equal to 57 micrometers, can improve brightness and brightness uniformity, meet TCO requirements, and avoid moiré patterns.

[0097] In some embodiments, the third distance corresponding to the first prism structure is equal to the third distance corresponding to the second prism structure, and the fourth distance corresponding to the first prism structure is equal to the fourth distance corresponding to the second prism structure; or, the third distance corresponding to the first prism structure is not equal to the third distance corresponding to the second prism structure, and the fourth distance corresponding to the first prism structure is not equal to the fourth distance corresponding to the second prism structure.

[0098] In some embodiments, as shown in FIG21, the first prism structure 2 further includes: a first haze layer 1401 located on the side of the first substrate 401 opposite to the first prism repeating unit 701;

[0099] The second prism structure 3 also includes a second haze layer 1402 located on the side of the second substrate 4 opposite to the second prism repeating unit.

[0100] The backlight module provided in this embodiment includes a haze layer in both the first prism structure and the second prism structure. This allows the light to be dispersed evenly after reaching the haze layer, which is more conducive to improving the uniformity of the emitted light brightness.

[0101] In some embodiments, the haze of the first haze layer is greater than or equal to 25% and less than or equal to 60%.

[0102] It should be noted that when the haze of the first haze layer is less than 25%, the backlight module does not meet the TCO requirements; when the haze of the first haze layer is greater than 60%, the backlight module suffers severe brightness loss. The backlight module provided in this embodiment has a haze of the first haze layer greater than or equal to 25% and less than or equal to 60%, thereby meeting the TCO requirements while avoiding loss of backlight module brightness.

[0103] In some embodiments, the haze of the second haze layer is greater than or equal to 7% and less than or equal to 17%.

[0104] It should be noted that when the haze of the second haze layer is less than 7%, the poor shading of the haze layer affects the uniform dispersion of light; when the haze of the second haze layer is greater than 17%, the brightness of the backlight module is severely lost. The backlight module provided in this embodiment has a haze of the second haze layer greater than or equal to 7% and less than or equal to 17%, thereby ensuring uniform light dispersion while avoiding loss of backlight module brightness.

[0105] In some embodiments, as shown in FIG3, the angle α1 between the first direction Y1 and the third direction X1 is greater than or equal to 60° and less than 90°;

[0106] The angle a2 between the fourth direction Y2 and the second direction X is less than or equal to 5° and less than or equal to 20°.

[0107] It should be noted that in the related technologies, in the double-layer prism sheet, the lower prism sheet corresponds to the first prism structure of the present disclosure embodiment, and the extension direction of the prisms included in the lower prism sheet is perpendicular to the second direction involved in the present disclosure embodiment. The upper prism sheet corresponds to the second prism structure of the present application, and the extension direction of the prisms included in the upper prism sheet is parallel to the second direction involved in the present disclosure embodiment. The brightness distribution of the light emitted from the backlight module is related to the extension direction of the prisms. In the related technologies, when the extension direction of the prisms included in the upper prism sheet is parallel to the second direction involved in the present disclosure embodiment, and the extension direction of the prisms included in the lower prism sheet is perpendicular to the second direction involved in the present disclosure embodiment, the arrangement of the double-layer prism in the related technologies causes more light to converge in the 0° direction perpendicular to the screen, sacrificing the viewing angle. When the backlight module including this double-layer prism sheet is applied to display products, it cannot meet the viewing angle requirements of TCO for the brightness uniformity of display products. The backlight module provided in this disclosure, by designing the extension direction of the prisms in each prism structure, enables the backlight module to meet the TCO (Total Cost of Ownership) requirements for viewing angle uniformity of brightness in display products. Compared with the prior art, the backlight module provided in this disclosure can improve brightness by about 8%-13% and contrast ratio by about 50-150. Relevant test data are shown in Table 1, where F1 is a backlight module of the related technology, and F2 and F3 are backlight modules provided in this disclosure. In the backlight module F2, a2 ​​= 15°, a1 = 70°, the haze of the first haze layer is 40%, the second distance in both the first and second prism structures is 0, the ratio of the first distance to the thickness of the first prism in the first prism structure is 40%, and the ratio of the first distance to the thickness of the second prism in the second prism structure is 15%. In the backlight module F3, a2 = 15°, a1 = 75°, the first haze layer... The haze of the light layer is 50%, the second distance in both the first prism structure and the second prism structure is 0, the ratio of the first distance to the thickness of the first prism in the first prism structure is 50%, and the ratio of the first distance to the thickness of the second prism in the second prism structure is 15%. As can be seen from Table 1, compared with related technologies, the brightness L255 of the backlight modules F2 and F3 provided in this embodiment is significantly increased at the 255 gray level; the brightness of F2 and F3 is improved; the horizontal TCO and vertical TCO values ​​are both increased, that is, the uniformity of viewing angle brightness is improved.

[0108] Table 1

[0109] In some embodiments, the angle a2 between the fourth direction Y2 and the second direction X is greater than or equal to 12° and less than or equal to 17°;

[0110] The angle a1 between the first direction Y1 and the second direction X is greater than or equal to 70° and less than or equal to 80°.

[0111] For ease of simulation analysis, the specific viewing angle of the backlight module, including the horizontal viewing angle, can be calculated using the following formula: Vertical perspective: When a backlight module is applied to a display product, the length of the display area is H, the width is V, and the diagonal length is D. The brightness at the specific viewing angle is tested to determine whether the TCO standard is met. When the backlight module is applied to a display product, the aspect ratio of the display product is fixed, and a specific viewing angle can be fixed. For example, when the aspect ratio of the display product H:V = 16:9, ∠A = 17.17°, ∠B = 40.22°, ∠E = 7.55°, and ∠F = 21.96°.

[0112] In the simulation of the backlight module provided in the embodiments of this disclosure, the simulated range of the angle a1 between the fourth direction Y2 and the second direction X is greater than or equal to 60° and less than 90°; the simulated range of the angle a2 between the first direction Y1 and the second direction X is greater than or equal to 5° and less than or equal to 30°. When a2 is less than 12°, TCO cannot be achieved; when a2 is greater than 17°, the asymmetry of left and right darkening cannot be resolved. When a1 is less than 70°, the brightness gain is insufficient; when a1 is greater than 80°, TCO cannot be achieved. The light pattern diagrams for a2 = 30° and a1 = 75° are shown in Figure 18, and the light pattern diagrams for a2 = 15° and a1 = 70° are shown in Figure 19. Compared with the light pattern diagrams in Figure 18, the light pattern diagrams in Figure 19 show a clockwise rotation of the screen brightness direction to a horizontal symmetry when a2 = 15° and a1 = 70°, which can improve the poor symmetry of the darkened screen. In Figure 19, the brightness at an angle of 17.17° meets the horizontal TCO requirement, while the brightness at angles of 7.55° and 21.96° meets the vertical TCO requirement. Compared with Figure 18, in Figure 19, the brightness at the eye diagram energy cyclotron center at a brightness of 40.22° increases in the horizontal TCO, thus improving the TCO effect and enhancing brightness uniformity.

[0113] The backlight module provided in this embodiment has a value of a2 greater than or equal to 12°, which allows the backlight module to meet the TCO requirements. A value of a2 less than or equal to 17° can avoid display defects such as asymmetry in left and right darkening. A value of a1 greater than or equal to 70° can significantly improve the brightness gain of the backlight module, thereby improving brightness uniformity. A value of a1 less than or equal to 80° can make the backlight module meet the TCO requirements.

[0114] In some embodiments, the included angle α5 between the first direction Y1 and the fourth direction Y2 is greater than or equal to 50° and less than or equal to 60°. This can further improve brightness uniformity.

[0115] In some embodiments, as shown in FIG3, FIG4 and FIG20, the first prism structure 2 includes a first prism repeating unit 701, and the second prism structure 3 includes a second prism repeating unit 702.

[0116] The number of first prisms 6 included in the first prism repeating unit 701 is equal to the number of second prisms 6 included in the second prism repeating unit 702.

[0117] In some embodiments, as shown in Figures 3 and 4, the prism repeating unit 7 includes two prisms 6.

[0118] Alternatively, in some embodiments, as shown in FIG20, the prism repeating unit 7 may include 3 prisms 6.

[0119] In practice, when the prism repeating unit includes two prisms, the improvement in brightness and brightness uniformity is better compared to when the prism repeating unit includes more prisms.

[0120] In some embodiments, as shown in FIG22, the first prism 6 has a first apex angle a3 corresponding to the ridge line 10 along a cross section perpendicular to the first direction Y1; as shown in FIG24, the second prism 6 has a second apex angle a4 corresponding to the ridge line 10 along a cross section perpendicular to the third direction X1.

[0121] The first vertex angle a3 is greater than or equal to 91° and less than or equal to 94°, or, as shown in Figure 23, the first vertex angle is a rounded corner, and the central angle a5 corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°.

[0122] The second vertex angle a4 is greater than or equal to 91° and less than or equal to 94°, or, as shown in Figure 25, the second vertex angle is a rounded corner, and the central angle a6 corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°.

[0123] It should be noted that when the first apex angle, the second apex angle, or the central angle corresponding to the first apex angle and the second apex angle are less than 91° or greater than 94°, it is impossible to simultaneously meet the TCO requirement and the backlight module brightness gain. However, the backlight module provided in this disclosure, with its first apex angle greater than or equal to 91° and less than or equal to 94°, or the central angle corresponding to the first apex angle and the second apex angle greater than or equal to 91° and less than or equal to 94°, can simultaneously meet the TCO requirement and the brightness gain, thus improving the display effect.

[0124] In some embodiments, the refractive index of the prism layer is greater than or equal to 1.54 and less than or equal to 1.60.

[0125] In practical implementation, the higher the refractive index of the prism layer, the better the brightness uniformity of the backlight module. A refractive index of 1.54 or higher can achieve good brightness uniformity, avoiding horizontal asymmetry in the brightness of the left and right sides of the screen. When the refractive index of the prism layer is greater than 1.6, its scratch resistance will decrease significantly, affecting the yield and lifespan of the prism layer. Therefore, the backlight module provided in this embodiment has a prism layer with a refractive index greater than or equal to 1.54 and less than or equal to 1.60, which can improve the brightness uniformity of the backlight module while ensuring the scratch resistance of the prism layer.

[0126] An embodiment of this disclosure provides a display device, as shown in FIG26. The display device includes: a backlight module 15 provided in this disclosure embodiment, and a display panel 16 located on the light-emitting side of the backlight module 15.

[0127] In a specific implementation, the display panel is, for example, a liquid crystal display panel, as shown in FIG26. The display panel 16 includes: an array substrate 1601 and a counter substrate 1602 disposed opposite to each other, and a liquid crystal layer 1603 located between the array substrate 1601 and the counter substrate 1602.

[0128] The display device provided in this disclosure includes any product or component with a display function, such as a mobile phone, tablet computer, television, monitor, laptop computer, digital photo frame, or navigator. Other essential components of this display device are understood by those skilled in the art and will not be described in detail here, nor should they be construed as limiting this disclosure. Implementation of this display device can refer to the embodiments of the display panel described above; repeated details will not be repeated.

[0129] In summary, in the backlight module and display device provided in this disclosure, in at least one of the first prism structure and the second prism structure, the distance from the valley line between adjacent prisms in the repeating unit to the substrate is different from the distance from the valley line between two prisms in the adjacent repeating unit to the substrate. That is, the valley lines between prisms in the prism layer are located on different planes. Compared with conventional prisms where the valley lines between prisms are on the same plane, this can improve the center brightness and the uniformity of brightness at different viewing angles. When the backlight module is applied to a display product, it avoids the defect of uneven brightness and asymmetry between the left and right sides of the display product, thus improving the display effect. Furthermore, the angle α5 between the extension direction of the prism in the first prism structure and the extension direction of the prism in the second prism structure is greater than or equal to 50° and less than or equal to 60°. Compared with the case where the extension directions of the prisms in the upper and lower prism structures are perpendicular, this can further improve the brightness uniformity.

[0130] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0131] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

A backlight module, wherein, The backlight module includes: a light source assembly, a first prism structure located on the light-emitting side of the light source assembly, and a second prism structure located on the side of the first prism structure facing away from the light source assembly; Both the first prism structure and the second prism structure include: a substrate, and a prism layer located on the side of the substrate opposite to the light source assembly; the prism layer includes a plurality of prisms, which are arranged sequentially along a direction intersecting its extending direction; In at least one of the first prism structure and the second prism structure, all the prisms in the prism layer are divided into multiple prism repeating units, and each prism repeating unit includes multiple prisms; the distance from the valley line formed by the side surfaces of any two adjacent prisms in the prism repeating unit to the substrate is a first distance, and the distance from the valley line formed by the side surfaces of adjacent prisms in two prism repeating units to the substrate is a second distance, wherein the first distance is greater than the second distance; The angle between the extension direction of the prism in the first prism structure and the extension direction of the prism in the second prism structure is greater than or equal to 40° and less than or equal to 65°. According to claim 1, the backlight module, wherein, All prisms in the prism layer have the same thickness in the direction perpendicular to the substrate. According to claim 1, the backlight module, wherein, In the prism layer including the prism repeating unit, the distance between the ridges of two adjacent prisms in the prism repeating unit is the third distance, and the distance between the ridges of two adjacent prisms located in different prism repeating units is the fourth distance. The third distance is greater than or equal to 27 micrometers and less than or equal to 47 micrometers, the fourth distance is greater than or equal to 37 micrometers and less than or equal to 57 micrometers, and the third distance is less than the fourth distance. According to claim 1, the backlight module, wherein, The first prism structure includes: a first substrate, and a plurality of repeating first prism units arranged on the side of the first substrate away from the light source assembly. The repeating first prism unit includes: a plurality of first prisms extending along a first direction; the first direction intersects with a second direction, and the second direction is the horizontal direction of the backlight module. The second prism structure includes: a second substrate, and a plurality of repeating second prism units located on the side of the second substrate facing away from the first prism structure and arranged along a third direction; the repeating second prism unit includes: a plurality of second prisms arranged along the third direction and extending along a fourth direction; the third direction is perpendicular to the fourth direction, and the second direction intersects both the third direction and the fourth direction; The angle between the first direction and the second direction is greater than or equal to 60° and less than 90°, and the angle between the fourth direction and the second direction is greater than or equal to 5° and less than or equal to 20°. According to claim 4, the backlight module, wherein, The angle between the second direction and the first direction is greater than or equal to 70° and less than or equal to 80°; The angle between the fourth direction and the second direction is greater than or equal to 12° and less than or equal to 17°. According to claim 5, the backlight module, wherein, The angle between the first direction and the fourth direction is greater than or equal to 50° and less than or equal to 60°. The backlight module according to any one of claims 4 to 6, wherein, The first prism structure further includes a first haze layer located on the side of the first substrate opposite to the first prism repeating unit. According to claim 7, the backlight module, wherein, The haze of the first haze layer is greater than or equal to 25% and less than or equal to 60%. According to claim 7, the backlight module, wherein, The second prism structure further includes a second haze layer located on the side of the second substrate opposite to the second prism repeating unit. According to claim 9, the backlight module, wherein, The haze of the second haze layer is greater than or equal to 7% and less than or equal to 17%. The backlight module according to any one of claims 4-6 and 8-10, wherein, The first prism has a first apex angle corresponding to the ridge line along a cross section perpendicular to the first direction; the second prism has a second apex angle corresponding to the ridge line along a cross section perpendicular to the third direction. The first vertex angle is greater than or equal to 91° and less than or equal to 94°, or the first vertex angle is a rounded corner, and the central angle corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°; The second vertex angle is greater than or equal to 91° and less than or equal to 94°, or the second vertex angle is a rounded corner, and the central angle corresponding to the rounded corner is greater than or equal to 91° and less than or equal to 94°. The backlight module according to any one of claims 4-6 and 8-10, wherein, The first prism structure includes a first prism repeating unit, and the second prism structure includes a second prism repeating unit; The number of first prisms included in the first prism repeating unit is equal to the number of second prisms included in the second prism repeating unit. The backlight module according to any one of claims 1 to 6, 8 to 10, wherein, The refractive index of the prism layer is greater than or equal to 1.54 and less than or equal to 1.

60. The backlight module according to any one of claims 1 to 6, 8 to 10, wherein, The backlight module further includes a diffusion film located on the side of the first prism structure opposite to the second prism structure. A display device, wherein, The display device includes: a backlight module according to any one of claims 1 to 14, and a display panel located on the light-emitting side of the backlight module.

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