CN117742042A

CN117742042A - Backlight module and display device

Info

Publication number: CN117742042A
Application number: CN202410141001.1A
Authority: CN
Inventors: 胡建; 田�健; 董文波; 丰兴坤; 黄聪杰
Original assignee: BOE Technology Group Co Ltd; Hefei BOE Ruisheng Technology Co Ltd
Current assignee: BOE Technology Group Co Ltd; Hefei BOE Ruisheng Technology Co Ltd
Priority date: 2024-01-31
Filing date: 2024-01-31
Publication date: 2024-03-22

Abstract

The invention discloses a backlight module and a display device, wherein the backlight module comprises: the light source and the at least one brightness enhancement structure film are positioned on the light emitting side of the light source; the brightness enhancement film comprises a substrate and a prism layer, wherein the prism layer is positioned on one side of the substrate, which is away from the light source; the substrate comprises a light incident surface, a light emergent surface and two opposite transflective layers, wherein the plane where the transflective layers are positioned is intersected with the light incident surface and the light emergent surface, and the transflective layers are at least used for reflecting incident light rays to the prism layers, so that the light rays which are originally emitted from the side wall of the substrate can be reflected to the prism layers to be utilized, the utilization rate of the light rays is improved, and the light rays which are incident to the transflective layers can be reflected to the vicinity of the edge of a display area by reasonably designing the inclination degree of the transflective layers, so that the brightness of the light rays at the vicinity of the edge of the display area is improved, the phenomenon of dark bands is avoided, and the light emergent uniformity of the backlight module is improved.

Description

Backlight module and display device

Technical Field

The present invention relates to the field of display technologies, and in particular, to a backlight module and a display device.

Background

In a liquid crystal display (Liquid Crystal Display, abbreviated as LCD) device, a backlight module is required to provide backlight for the liquid crystal display panel, which cannot emit light. The Mini light emitting diode (Mini Light Emitting Diode, abbreviated as Mini LED) has the advantages of high brightness, high contrast, high color gamut, long service life, etc., and is often applied to a backlight module as a backlight source thereof.

For the consideration of structural stability of the Mini LED, the distance between the Mini LED and the edge of the display area is designed to be larger, so that the brightness near the edge of the display area is lower to generate a dark band, the uniformity of light emitted by the backlight module is affected, and the display effect is further affected.

The methods commonly used at present for improving the dark bands at the edge of the display area are as follows: a white rubber frame is arranged at the edge of the display area, but the phenomenon of bluing of the edge of the backlight module is possibly aggravated; or, white retaining walls are arranged in the intervals between the Mini LEDs and the edges of the display area, and special microstructures are designed on the white retaining walls, but the method has higher requirements on the installation precision and has great process difficulty; or silver plating is carried out on the lamp panel under the dark band area, and meanwhile, a special microstructure is designed on the surface of the lamp panel to improve the light scattering angle; or, a diffusion film with an edge gradual change treatment is arranged in the backlight module so as to improve the light scattering angle, but the risk of falling of diffusion particles at the edge of the diffusion film is higher, and black spots are easy to appear on a display picture.

Disclosure of Invention

The invention provides a backlight module and a display device, which are used for improving the phenomenon of dark bands caused by lower brightness near the edge of a display area.

In a first aspect, the present invention provides a backlight module, including:

a light source;

at least one brightness enhancing structural film positioned on the light emitting side of the light source; the brightness enhancement film comprises a substrate and a prism layer, wherein the prism layer is positioned on one side of the substrate away from the light source; the substrate comprises a light incident surface, a light emergent surface and two opposite transparent and reflective layers, wherein the plane where the transparent and reflective layers are positioned is intersected with the light incident surface and the light emergent surface, and the transparent and reflective layers are at least used for reflecting incident light rays to the prism layers.

In some embodiments of the present invention, the substrate includes a first prism, a second prism, and a third prism sequentially arranged along a first direction;

the two opposite transflective layers comprise a first transflective layer and a second transflective layer; the first transflective layer is positioned between the first prism and the second prism, the first transflective layer is positioned on a surface of the first prism facing the second prism, or the first transflective layer is positioned on a surface of the second prism facing the first prism; the second transflective layer is positioned between the second prism and the third prism, the second transflective layer is positioned on a surface of the second prism facing the third prism, or the second transflective layer is positioned on a surface of the third prism facing the second prism.

In some embodiments of the invention, the first and second transflector layers are parallel to each other.

In some embodiments of the present invention, the distance between the first transflective layer and the second transflective layer in the first direction increases gradually along a second direction, and the second direction is a direction perpendicular to the light incident surface and pointing from the light incident surface to the light emergent surface.

In some embodiments of the present invention, a length of the orthographic projection of the first transflective layer on the light incident surface in the first direction is a first length, a minimum distance between the first transflective layer and the second transflective layer in the first direction is a second length, a length of the orthographic projection of the second transflective layer on the light incident surface in the first direction is a third length, and a ratio of the first length, the second length, and the third length ranges from 1:98:1 to 10:80:10.

In some embodiments of the present invention, the transflective layer includes a plurality of light reflecting portions, the plurality of light reflecting portions are arranged in an array, and a space is provided between adjacent light reflecting portions;

the light reflecting parts are used for reflecting light rays to the prism layers, and the intervals of the light reflecting parts are used for transmitting the light rays.

In some embodiments of the present invention, the backlight module further includes: the reflection frame surrounds the at least one brightness enhancement structure film, and the reflection frame is used for reflecting light rays transmitted at intervals of the reflection part to one side deviating from the light source.

In some embodiments of the invention, the transflector is disposed entirely.

In some embodiments of the invention, in the first direction, a maximum length of the first prism is less than a maximum length of the second prism, and the maximum length of the second prism is greater than a maximum length of the third prism.

In some embodiments of the invention, in the first direction, a maximum length of the first prism is equal to a maximum length of the third prism.

In some embodiments of the present invention, the material used for the transflector layer comprises a metallic material comprising one or more of silver or aluminum.

In some embodiments of the invention, the substrate is made of a material including one or more of tantalum pentoxide, silicon dioxide, or borosilicate crown glass.

In some embodiments of the present invention, the backlight module includes two brightness enhancement films; the two brightness enhancement films comprise a first brightness enhancement film and a second brightness enhancement film, and the second brightness enhancement film is positioned at one side of the first brightness enhancement film away from the light source;

In the first brightness enhancement film, the two opposite transparent and reflective layers are arranged at intervals in a third direction, and in the second brightness enhancement film, the two opposite transparent and reflective layers are arranged at intervals in a fourth direction, and the third direction is perpendicular to the fourth direction.

In a second aspect, the present invention further provides a display device, where the display device includes a display panel and any one of the backlight modules described above, and the display panel is located on a light emitting side of the backlight module.

The invention has the following beneficial effects:

the invention provides a backlight module and a display device, wherein the backlight module comprises: the light source and the at least one brightness enhancement structure film are positioned on the light emitting side of the light source; the brightness enhancement film comprises a substrate and a prism layer, wherein the prism layer is positioned on one side of the substrate, which is away from the light source; the substrate comprises a light incident surface, a light emergent surface and two opposite transflective layers, wherein the plane where the transflective layers are positioned is intersected with the light incident surface and the light emergent surface, and the transflective layers are used for reflecting incident light rays to the prism layers, so that the light rays which are originally emitted from the side wall of the substrate can be reflected to the prism layers to be utilized, the utilization rate of the light rays is improved, and the light rays which are incident to the transflective layers can be reflected to the vicinity of the edge of a display area by reasonably designing the inclination degree of the transflective layers, so that the brightness of the light rays at the vicinity of the edge of the display area is improved, the phenomenon of dark bands is avoided, and the light emergent uniformity of the backlight module is improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a cross-sectional view of a display device according to an embodiment of the present invention;

fig. 2 is a cross-sectional view of a backlight module according to an embodiment of the present invention;

FIG. 3 is a top view of a light source according to an embodiment of the present invention;

FIG. 4 is a schematic view of the overall structure of a brightness enhancement film according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a prism layer according to an embodiment of the present invention;

FIG. 6 is a schematic view of the overall structure of another brightness enhancement film according to an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a two-layer brightness enhancement film according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of a structure of a transflective layer according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of an optical path according to an embodiment of the present invention;

FIG. 10 is a schematic view of another optical path provided by an embodiment of the present invention;

FIG. 11 is a schematic view of an exploded structure of a substrate according to an embodiment of the present invention;

reference numerals illustrate:

the backlight module 100, the display panel 200, the light source 1, the substrate 11, the light emitting device 12, the display area AA, the first pitch Q1, the second pitch Q2, the interval area BB, the first sub-interval area BB1, the second sub-interval area BB2, the third sub-interval area BB3, the fourth sub-interval area BB4, the light homogenizing layer 2, the brightness enhancing structure film 3, the substrate 31, the light incident surface 311, the light emergent surface 312, the side 313, the prism layer 32, the prism structure 321, the transflective layer 33, the first transflective layer 331, the second transflective layer 332, the reflective portion R, the first brightness enhancing structure film 301, the second brightness enhancing structure film 302, the wavelength selective layer 4, the wavelength conversion layer 5, the brightness enhancing layer 6, the prism film 61, the reflective polarizer 62, the reflective frame 7, the first direction D1, the second direction D2, the third direction D3, the fourth direction D4, the fifth direction D5, the sixth direction D6, the first length w1, the second length w2, the third length w3, the first width h1, the third width h2, the third width h3, the third width L2, the third width L3, the third prism L2, the third width L2, the third light ray L2, the prism L2, the third light ray L2.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a further description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. However, the exemplary embodiments can be embodied in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art. The same reference numerals in the drawings denote the same or similar structures, and thus a repetitive description thereof will be omitted. The words expressing the positions and directions described in the present invention are described by taking the drawings as an example, but can be changed according to the needs, and all the changes are included in the protection scope of the present invention. The drawings of the present invention are merely schematic representations of relative positional relationships and are not intended to represent true proportions.

Fig. 1 is a cross-sectional view of a display device according to an embodiment of the present invention.

As shown in fig. 1, in an embodiment of the present invention, a display device includes: the backlight module 100 and the display panel 200, wherein the backlight module 100 adopts a direct type backlight module, and can be used for providing backlight to the display panel 200, and the backlight module 100 is usually located at the bottom of the display device, and the shape and size of the backlight module are adapted to those of the display device.

The display panel 200 is located at the light emitting side of the backlight module 100, and may be used to implement image display, and exemplary, the display panel 200 may employ a liquid crystal display panel. The shape and size of the display panel 200 are adapted to those of the backlight unit, and the display area of the display device is adapted to the area where the display panel 200 is located.

Fig. 2 is a cross-sectional view of a backlight module according to an embodiment of the invention.

As shown in fig. 2, in the embodiment of the present invention, the backlight module 100 may include, but is not limited to, a light source 1, a light homogenizing layer 2, a brightness enhancing structure film 3, a wavelength selective layer 4, a wavelength conversion layer 5, a brightness enhancing layer 6, and the like.

Wherein the light source 1 may comprise a substrate 11 and a plurality of light emitting devices 12 disposed on the substrate 11. The substrate 11 may employ one of a glass substrate, a printed circuit board (Printed Circuit Board, abbreviated as PCB), an aluminum (Al) substrate, or a flexible circuit board (Flexible Printed Circuit, abbreviated as FPC), for example. The Light Emitting device 12 may be, but is not limited to, a Light Emitting Diode (Light Emitting Diode, LED), a Mini LED, a Micro LED, an Organic Light-Emitting Diode (OLED), or the like. The embodiment of the invention is described by taking a case that the light source 1 adopts a Mini LED lamp panel as an example, wherein the light emitting device 12 can be a Mini LED chip or a Mini LED lamp bead.

Fig. 3 is a top view of a light source according to an embodiment of the present invention.

As shown in fig. 3, in order to ensure structural stability of the light emitting device 12, when designing the light source 1, a distance between the light emitting device 12 near the edge of the display area AA and the edge of the display area AA is designed to be larger, and illustratively, in the first direction D1, a distance between the light emitting device 12 near the edge of the display area AA and the edge of the display area AA is a first distance Q1, and in the fourth direction D4, a distance between the light emitting device 12 near the edge of the display area AA and the edge of the display area AA is a second distance Q2, and the first distance Q1 and the second distance Q2 may be 5mm to 15mm. For convenience of description, the above-mentioned area is referred to as a spacing area BB in the embodiment of the present invention, since the light emitting device 12 is not disposed in the spacing area BB, the amount of light emitted from the area is smaller than that of the other areas of the display area AA, which may result in lower brightness of the light emitted from the spacing area BB, and a dark band is observed in the spacing area BB, which affects uniformity of light emitted from the backlight module, and further affects display effect of the display device.

Based on this, the embodiment of the present invention provides at least one brightness enhancement film 3 on the light-emitting side of the light source 1 to avoid the occurrence of the dark band phenomenon in the above-described interval region BB. Fig. 4 is a schematic overall structure of a brightness enhancement film according to an embodiment of the present invention.

As shown in fig. 4, in the embodiment of the present invention, the brightness enhancing film 3 includes a substrate 31 and a prism layer 32, and the prism layer 32 is located on the side of the substrate 31 facing away from the light source 1.

The substrate 31 includes a light incident surface 311 and a light emergent surface 312, the light incident surface 311 is located at a side close to the light source 1, and the light emergent surface 312 is located at a side close to the prism layer 32. The material of the substrate 31 is a material having a high transmittance, for example, the material of the substrate 31 may include tantalum pentoxide (Ta ₂ O ₅ ) Silicon dioxide (SiO) ₂ ) Or borosilicate crownOne or more of the glasses (BK 7 glass) so that most of the light emitted from the light source 1 can be incident into the inside of the substrate 31 through the light incident surface 311 of the substrate 31, propagate into the light emergent surface 312 of the substrate 31 inside the substrate 31, and be incident into the prism layer 32.

Fig. 5 is a schematic structural diagram of a prism layer according to an embodiment of the present invention.

As shown in fig. 5, the prism layer 32 may include a plurality of prism structures 321 extending in the same direction, the plurality of prism structures 321 are arranged in the first direction D1, and light incident on the prism layer 32 from the light-emitting surface 312 of the substrate 31 may be emitted from the prism layer 32 with greater brightness.

The principle of brightness enhancement of the prismatic layer 32 is as follows: the prism structure 321 can concentrate the light incident to the prism layer 32 to emit within a set angle range, for example, the set angle range, that is, the front view angle range, may be 60 ° to 70 °, and the light having the emitting angle not within the range is recycled by reflection, refraction, total reflection, and other manners, so as to increase the light emitting efficiency within the set angle range and improve the light emitting brightness.

The shape, size, arrangement, etc. of the plurality of prism structures 321 in the prism layer 32 may be designed according to the specific situation, the embodiment of the present invention is not limited herein, and illustratively, the apex angle θ of each prism structure 321 may be 90 °, the distance D3 between two adjacent prism structures 321 may be 50 μm, the width D2 of each prism structure 321 in the first direction D1, and the height D3 of each prism structure 321 in the second direction D2 may be designed according to the size of the display device, and the width D2 and the height D3 may be in the micrometer scale. Materials that may be used for the prismatic structure 321 include tantalum pentoxide (Ta ₂ O ₅ ) Silicon dioxide (SiO) ₂ ) Or borosilicate crown glass (BK 7 glass).

Referring to fig. 4, in the embodiment of the present invention, the substrate 31 of the brightness enhancement film 3 includes two opposite transflective layers 33, and the plane of the transflective layers 33 intersects with the light incident surface 311 and the light emergent surface 312 of the substrate 31, that is, the transflective layers 33 are obliquely arranged. Since the light emitting angle of the Mini LED is generally in the range of 120 ° to 165 °, and the substrate 31 is made of a light-transmitting material, when the transflective layer 33 is not provided, part of the light emitted from the Mini LED will be emitted from the side 313 of the substrate 31, so that the part of the light cannot be emitted from the front view angle, and a part of the light is lost. In the embodiment of the present invention, the part of light may be incident on the surface of the transflective layer 33, and the transflective layer 33 may reflect the light incident on the surface thereof toward the prism layer, so that on one hand, the light utilization rate may be improved, and on the other hand, by designing the inclination degree of the transflective layer 33, the part of light may be reflected to the prism structure 321 above the interval area BB, and based on the above-mentioned brightness enhancement principle, the part of light may be utilized, so that the brightness of the light exiting from the interval area BB may be improved, and dark bands near the edge of the display area AA may be avoided.

Referring to fig. 4, in an embodiment of the present invention, two opposite transflective layers 33 include a first transflective layer 331 and a second transflective layer 332, and the first and second transflective layers 331 and 332 may be parallel to each other.

Fig. 6 is a schematic overall structure of another brightness enhancement film according to an embodiment of the present invention.

The difference between the brightness enhancement film 3 according to the embodiment of the present invention and the embodiment shown in fig. 4 is that the arrangement of the transflective layer 33 in the brightness enhancement film 3 is different, as shown in fig. 6, in the embodiment of the present invention, the distance between the first transflective layer 331 and the second transflective layer 332 in the first direction D1 is gradually increased, that is, the tilt directions of the first transflective layer 331 and the second transflective layer 332 are different.

In the brightness enhancing structured film 3 as shown in fig. 4 and 6, the degree of inclination of the transflective layer 33 may be determined according to the following conditions: the length of the orthographic projection of the first transparent and reflective layer 331 on the light incident surface 311 in the first direction D1 is a first length w1, the minimum distance between the first transparent and reflective layer 331 and the second transparent and reflective layer 332 in the first direction D1 is a second length w2, the length of the orthographic projection of the second transparent and reflective layer 332 on the light incident surface 311 in the first direction D1 is a third length w3, and the ratio of the first length w1, the second length w2 and the third length w3 ranges from w1:w2:w3 to 1:98:1 to 10:80:10.

In addition, for the brightness enhancement film 3 shown in fig. 4, the first length w1 is less than or equal to the width of the interval region BB in the first direction D1, that is, the first pitch Q1, so that the orthographic projection of the first transflective layer 331 on the light source 1 does not overlap with the light emitting device 12, and the light emitted from the light emitting device 12 hardly directly enters from the region of the first transflective layer 331 on the side facing away from the second transflective layer 332, and no additional light loss is caused. Similarly, for the brightness enhancing film 3 shown in fig. 6, the first length w1 and the third length w3 are smaller than or equal to the width of the spacing region BB in the first direction D1, that is, the first pitch Q1, so that the orthographic projection of the first and second transflective layers 331 and 332 on the light source 1 does not overlap with the light emitting device 12, and the light emitted from the light emitting device 12 hardly directly enters from the region on the side of the first transflective layer 331 facing away from the second transflective layer 332 or the region on the side of the second transflective layer 332 facing away from the first transflective layer 331, and no additional light loss is caused.

The brightness of the interval region BB near the two edge lines opposite to each other of the display region AA can be enhanced by providing two transflective layers 33 having a set degree of inclination in the substrate 31. For example, referring to fig. 3 and 4, the interval region BB includes opposite first and second sub-interval regions BB1 and BB2, and opposite third and fourth sub-interval regions BB3 and BB4, and the first and second transflective layers 331 and 332 are disposed at intervals in the first direction D1, and the number of outgoing light rays in the sub-interval regions aligned in the same direction as that thereof may be increased, i.e., the outgoing light luminance of the first and third sub-interval regions BB1 and BB3 may be increased.

In some embodiments, two layers of brightness enhancement films 3 may be disposed in the backlight module, so as to enhance the brightness of the light exiting from the whole interval region BB.

Fig. 7 is a schematic structural diagram of a two-layer brightness enhancement film according to an embodiment of the present invention.

Referring to fig. 2 and 7, in the embodiment of the present invention, the two brightness enhancement films 3 include a first brightness enhancement film 301 and a second brightness enhancement film 302, wherein the second brightness enhancement film 302 is located on a side of the first brightness enhancement film 301 facing away from the light source 1.

In the first brightness enhancement film 301, the first and second transflective layers 331 and 332 are disposed at intervals in the third direction D3, the plurality of prism structures 321 in the prism layer are arranged along the third direction D3, and the third direction D3 is set to be identical to the first direction D1 shown in fig. 3 and 4, so that the light reflected by the transflective layer 33 to the prism layer can exit in the two sub-interval regions BB arranged in the first direction D1, and the light-exiting brightness of the first and third sub-interval regions BB1 and BB3 is improved.

In the second brightness enhancement film 302, the first and second transflective layers 331 and 332 are disposed at intervals in the fourth direction D4, and the third direction D3 is perpendicular to the fourth direction D4, so that the light reflected by the transflective layer 33 to the prism layer can exit in the two sub-interval regions BB arranged in the fourth direction D4, and the brightness of the light exiting from the second sub-interval region BB2 and the fourth sub-interval region BB4 is improved.

According to the embodiment of the invention, the two brightness enhancement structure films 3 are arranged in the backlight module, each brightness enhancement structure film 3 can increase the quantity of emergent light rays of two opposite sub-interval regions, and the two brightness enhancement structure films 3 are vertically arranged, so that the quantity of emergent light rays of the whole interval region can be increased, the brightness of emergent light of the whole interval region BB is improved, and the phenomenon of dark bands at the edge of the display region AA is improved. In addition, the plurality of prism structures 321 in the prism layer 32 of the first brightness enhancement film 301 are arranged along the third direction D3, the plurality of prism structures 321 in the second brightness enhancement film 302 are arranged along the fourth direction D4, and the third direction D3 and the fourth direction D4 are perpendicular, that is, the two prism layers are perpendicular, so that the brightness of the entire display area AA can be further improved according to the brightness enhancement principle of the brightness enhancement film 3.

In a specific implementation, the first brightness enhancement film 301 and the second brightness enhancement film 302 may both use the brightness enhancement prism structure 321 as shown in fig. 4, or the first brightness enhancement film 301 and the second brightness enhancement film 302 may both use the brightness enhancement prism structure 321 as shown in fig. 6, or one of the first brightness enhancement film 301 and the second brightness enhancement film 302 uses the brightness enhancement prism structure 321 as shown in fig. 4, and the other uses the brightness enhancement prism structure 321 as shown in fig. 6. Hereinafter, a case where the first brightness enhancement film 301 and the second brightness enhancement film 302 may each employ the brightness enhancement prism structure shown in fig. 4 will be described as an example.

In specific implementation, the backlight module can be further provided with a plurality of brightness enhancement structure films 3, the brightness enhancement structure films 3 are arranged along the second direction D2, the structures of the brightness enhancement structure films 3 can be the same or different, and the placement angle can be set according to the requirements.

Fig. 8 is a schematic structural diagram of a transflective layer according to an embodiment of the present invention.

Fig. 8 (a) shows a plan view of the entire structure of the transreflective layer 33, and fig. 8 (b) shows a front view of the transreflective layer 33, and as shown in fig. 8 (a) and 8 (b), in an embodiment of the present invention, the transreflective layer 33 may include a plurality of light reflecting portions R arranged in an array with spaces between adjacent light reflecting portions R. The light reflecting portion R is made of a metal material, and the metal material includes one or more of silver and aluminum, and is formed by electroplating, physical vapor deposition (Physical Vapor Deposition, abbreviated as PVD), and the like. The light reflecting portions R may serve to reflect light toward the prism layer, and the interval of the light reflecting portions R may transmit light.

For example, the light reflecting portions R may be arranged in an array along a fifth direction D5 and a sixth direction D6, where the fifth direction D5 and the sixth direction D6 are extending directions of two intersecting sides on the surface of the transflective layer 33, and the intensity of the light reflecting portions R may be determined according to the following relationship:

The width of the surface of the transflective layer 33 in the fifth direction D5 is a first width h1, the minimum distance between the reflective portion R and the edge of the surface of the transflective layer 33 is a second width h2, and the distance between adjacent reflective portions R is a third width h3, wherein the percentage of the second width h2 in the first width h1 is a first percentage, the first percentage is 1% to 5%, the first percentage is determined by the accuracy of the coating process, the percentage of the third width h3 in the first width h1 is a second percentage, the range of the second percentage is 1% to 10%, and the smaller the second percentage is, the smaller the distance between adjacent reflective portions R in the fifth direction D5 is indicated.

Similarly, the width of the surface of the transflective layer 33 in the sixth direction D6 is the fourth width h4, the minimum distance between the reflective portion R and the edge of the surface of the transflective layer 33 is the second width h2, and the distance between the adjacent reflective portions R is the third width h3. Wherein the percentage of the second width h2 in the fourth width h4 is a third percentage, the range of the third percentage is 1% -5%, and the third percentage is determined by the precision of a coating process; the percentage of the third width h3 in the fourth width h4 is a fourth percentage, and the fourth percentage ranges from 1% to 10%, and the smaller the fourth percentage is, the smaller the interval between the adjacent light reflecting portions R in the sixth direction D6 is.

According to the embodiment of the invention, the third width h3 is designed to meet the second percentage and the fourth percentage, so that on one hand, the plurality of light reflecting portions R in the transparent and reflective layer 33 can have higher arrangement density, and enough light rays can be reflected to the prism layer 32 and emitted towards the front view angle direction, thereby improving the brightness of the light emitting brightness of the interval region BB, saving reflective materials and reducing cost while ensuring the brightness enhancement effect. On the other hand, the interval between the adjacent light reflecting portions R can be limited to a smaller range, and the amount of transmitted light in the interval between the light reflecting portions R is smaller, so that the light loss is reduced.

In practice, the transflective layer 33 in the brightness enhancing film 3 shown in fig. 4 and 6 may have the structure of the transflective layer 33 shown in fig. 8, and the arrangement density of the reflective portions R in the first and second transflective layers 331 and 332 may be the same or different. For the brightness enhancement film 3 shown in fig. 4, the second percentage and the fourth percentage of the second transflective layer 332 may be greater than the second percentage and the fourth percentage of the first transflective layer 331, respectively, so that the second transflective layer 332 transmits more light in the forward viewing angle direction, and the light utilization rate is improved. For the brightness enhancement film 3 shown in fig. 6, the transparent reflective layer 33 may be disposed entirely, and the surface on which the transparent reflective layer 33 is disposed is coated with a whole layer of reflective material by electroplating, PVD or evaporation, so that the light incident on the transparent reflective layer 33 may be reflected and incident on the prism layer 32, thereby improving the light utilization to a greater extent.

FIG. 9 is a schematic diagram of an optical path according to an embodiment of the present invention; fig. 10 is a schematic view of another optical path according to an embodiment of the present invention.

Fig. 9 shows a schematic view of the optical path in the substrate 31 of the first brightness enhancement film 301 of fig. 7, and fig. 10 shows a schematic view of the optical path in the substrate 31 of the second brightness enhancement film 302 of fig. 7. As shown in fig. 9 and 10, when the transflector 33 shown in fig. 8 is used, light is incident into the substrate 31 from the light incident surface 311 of the brightness enhancement prism, and the light incident into the reflecting layer includes, but is not limited to, several possible propagation paths, which are divided into a first light L1, a second light L2, a third light L3, and a fourth light L4 according to the propagation paths thereof, wherein the first light L1 is reflected by the light reflecting portions R of the first and second transflectors 331 and 332 toward the light emergent surface 312, the second light L2 is transmitted from the interval of the light reflecting portions R of the first and second transflectors 331 and exits from the side 313 of the substrate 31, the third light L3 is reflected by the light reflecting portions R of the first and second transflectors 331 and 332 toward the side 313 of the substrate 31, and the fourth light L4 is transmitted from the interval of the light reflecting portions R of the second transflector 332 and exits toward the light emergent surface 312.

Referring to fig. 2, the backlight module may further include a reflective frame 7, the orthographic projection of the reflective frame 7 on the substrate 11 surrounds the orthographic projection of each brightness enhancement film 3 on the substrate 11, and the height of the reflective frame 7 in the second direction D2 is greater than the distance between the prism layer 21 of the brightness enhancement film 3 farthest from the light source 1 and the light source 1, so that the reflective frame 7 may reflect the light emitted from the side 313 of the substrate 31, such as the second light L2 and the third light L3, to the side facing away from the light source 1, so as to further increase the utilization rate of the light emitted from the light source 1, and the light may also be incident into the interval area BB to enhance the brightness thereof, thereby improving the dark band phenomenon.

Fig. 11 is a schematic diagram of an exploded structure of a substrate according to an embodiment of the present invention.

As shown in fig. 4 and 11, in the embodiment of the present invention, the substrate 31 may include a first prism T1, a second prism T2, and a third prism T3 sequentially arranged along the first direction D1, the first transflective layer 331 is located between the first prism T1 and the second prism T2, the first transflective layer 331 may be located on a surface S1 of the first prism T1 facing the second prism T2, or the first transflective layer 331 may be located on a surface S2 of the second prism T2 facing the first prism T1; the second transflective layer 332 is positioned between the second prism T2 and the third prism T3, and the second transflective layer 332 may be positioned on a surface S3 of the second prism T2 facing the third prism T3, or the second transflective layer 332 may be positioned on a surface S4 of the third prism T3 facing the second prism T2.

In fabricating the substrate 31 of the brightness enhancing structured film 3, a reflective material may be plated on one of the surface S1 or the surface S2 to form the first transflective layer 331, a reflective material may be plated on one of the surface S3 or the surface S4 to form the second transflective layer 332, and then the first prism T1, the second prism T2, and the third prism T3 may be spliced together. The first prism T1, the second prism T2 and the third prism T3 are made of light-transmitting materials, so that the incident light rays can be reflected by plating the reflective materials on any one of the two adjacent surfaces.

For example, the surface S1 of the first prism T1 may be coated with the first transflective layer 331, the surface S4 of the third prism T3 may be coated with the second transflective layer 332, and then the first prism T1 and the third prism T3 may be spliced with the second prism T2, such that the first transflective layer 331 is located between the first prism T1 and the second prism T2, and the second transflective layer 332 is located between the second prism T2 and the third prism T3.

In the embodiment of the present invention, in the first direction D1, the maximum length of the first prism T1 is smaller than the maximum length of the second prism T2, the maximum length of the second prism T2 is greater than the maximum length of the third prism T3, and the ratio of the lengths of the first prism T1, the second prism T2 and the third prism T3 in the first direction D1 can satisfy a range of 1:98:1 to 10:80:10, so as to ensure that the inclination degree of the first transflective layer 331 and the second transflective layer 332 satisfies a requirement.

In order to make the volume of the substrate 31 as small as possible, as shown in fig. 11, the first prism T1 and the third prism T3 may be in a straight triangular prism structure, the second prism T2 is in an inclined triangular prism structure, the prism layer 32 may be disposed on a surface of the second prism T2 facing away from the light source 1, and during manufacturing, the prism layer 32 may be integrally formed with the second prism T2. The maximum length of the first prism T1 in the first direction D1 may be the same as the maximum length of the second prism T2 in the first direction D1, so as to form a symmetrical structure, which is beneficial to improving the light emitting uniformity.

To facilitate assembly of the substrate 31, the heights of the first, second, and third prisms T1, T2, and T3 may be the same, i.e., the thickness of the substrate 31 in the second direction D2 is uniform, and, for example, the thickness of the substrate 31 in the second direction D2 may be 0.4mm to 0.8mm.

Referring to fig. 2, in the embodiment of the invention, the backlight module 100 may further include the following film layer structure for improving the light emitting effect of the backlight module:

the backlight module 100 includes a light homogenizing layer 2, wherein the light homogenizing layer 2 is located between the light source 1 and the brightness enhancement film 3, and scattering particle materials are disposed in the light homogenizing layer 2, and light incident on the scattering particle materials is refracted and reflected continuously, so that the light is scattered, and the light homogenizing effect is achieved. The light equalizing layer 2 may have a plate-like structure having a certain thickness or a thin plate-like structure.

Illustratively, the light emitting devices 12 in the light source 1 emit light with the same color, and the backlight module further includes a wavelength conversion layer 5, where the wavelength conversion layer 5 is located on the light emitting side of the brightness enhancement film 3. The wavelength conversion layer 5 includes a wavelength conversion material, which can emit light of other colors under excitation of monochromatic light, so as to realize full-color display. For example, the light emitting device 12 may employ a blue light emitting device, and the wavelength conversion layer 5 includes a red light conversion material and a green light conversion material therein, the red light conversion material being excited to emit red light upon irradiation of blue light, the green light conversion material being excited to emit green light upon irradiation of blue light, whereby the wavelength conversion layer 5 emits red light and green light upon excitation of emission light of the blue light emitting device, and the blue light, the red light, and the green light are mixed into white light and emitted. In some embodiments, the wavelength converting material may be a quantum dot material, and in other embodiments, the wavelength converting material may be a fluorescent material.

A wavelength selective layer 4 may be further disposed between the wavelength conversion layer 5 and the brightness enhancement structure film 3, where the wavelength selective layer 4 may allow light of a set wavelength to pass therethrough, and block light of other wavelength bands than the set wavelength, thereby improving the light extraction efficiency of the light of the set wavelength. For example, when the light emitting device 12 is configured to emit blue light, the wavelength selective layer 4 may adopt a blue light transmissive film, the wavelength conversion layer 5 is disposed on the light emitting side of the blue light transmissive film, and the blue light transmissive film has a better transmittance for the blue light, so that the blue light is incident on the wavelength conversion layer 5 to excite the wavelength conversion material to emit red light and green light, thereby improving the light utilization rate, and simultaneously reflecting the red light and the green light, thereby improving the light emitting efficiency of the red light, the green light and the blue light, and increasing the light emitting brightness of white light formed by mixing the three.

For example, the backlight module 100 may further include a light enhancement layer 6, where the light enhancement layer 6 is located on the light emitting side of the wavelength conversion layer 5, and may include, for example, a prism film 61 (Brightness Enhancement Film, abbreviated as BEF) and a reflective polarizer 62 (Dual-Brightness Enhance Film, abbreviated as DBEF), where the DBEF is located on the light emitting side of the BEF, and the BEF may be used to concentrate the outgoing light with a large viewing angle to be emitted in a smaller viewing angle, increase the positive viewing angle brightness, and the DBEF may be used to selectively transmit the light with one polarization direction, such as P light, and reflect the light perpendicular to the polarization direction, such as S light, where the display panel 200 is generally provided with a polarizer or other structure, where the light may be reflected multiple times between the backlight module 100 and the display panel 200 and recycled, so as to enhance the brightness.

In specific implementation, the film structure in the backlight module 100 may be designed according to requirements, and the kind and arrangement order of the film structure are not limited in this embodiment of the invention.

Based on the above backlight module structure, the embodiment of the invention also tests the brightness of the light emitted by the backlight module, and the test results are shown in the following table:

	Data0(nit)	Data1(nit)	η1	Data2(nit)	η2
						test group 1	20100	16080	80％	15480	77％
Test group 2	20300	15225	75％	14616	72％
						Test group 3	19800	15050	76％	14058	71％
Test group 4	20000	15000	75％	14400	72％
						Test group 5	20070	14855	74％	14852	74％
Comparative group 1	21000	14700	70％	14280	68％
						Comparative group 2	20080	15665	78％	14055	70％

Wherein, the conditions of test group 1 were set as follows: the backlight module 100 includes two brightness enhancement films 3, the two brightness enhancement films 3 include a first brightness enhancement film 301 and a second brightness enhancement film 301, the structures of the first brightness enhancement film 301 and the second brightness enhancement film 302 refer to fig. 4, the arrangement mode of the two brightness enhancement films 3 refers to fig. 7, in each brightness enhancement film 3, the thickness of the substrate 31 is 0.50mm, the materials of the first prism T1 and the second prism T2 are BK7 glass (transmittance 92%, refractive index 1.51), the ratio w1:w2:w3 of the first length w1, the second length w2 and the third length w3 is 1:98:1, the structure of the reflective layer 33 in the brightness enhancement film 3 refers to fig. 8, the first percentage and the third percentage met by the second width h2 are 1%, and the second percentage and the fourth percentage met by the third width h3 are 1%. The backlight module 100 sequentially comprises a light source 1, a first brightness enhancement film 301, a second brightness enhancement film 302, a light homogenizing layer 2, a wavelength selective layer 4, a wavelength conversion layer 5, a prism film 61 and a reflective polarizer 62 along a second direction D2.

The conditions for test group 2 were set as follows: the backlight module comprises two brightness enhancement structure films 3, wherein the two brightness enhancement structure films 3 comprise a first brightness enhancement structure film 301 and a second brightness enhancement structure film 301, the structures of the first brightness enhancement structure film 301 and the second brightness enhancement structure film 302 are shown in fig. 4, the arrangement mode of the two brightness enhancement structure films 3 is shown in fig. 7, in each brightness enhancement structure film 3, the thickness of a substrate 31 is 0.50mm, and the materials of a first prism T1 and a second prism T2 are SiO ₂ (transmittance 85%, refractive index 1.35), the ratio of the first length w1, the second length w2, and the third length w3, w1:w2:w3, is 5:90:5, the structure of the transflective layer 33 in the brightness enhancing structure film 3 is shown in fig. 8, the first percentage and the third percentage are 5% for the second width h2, and the second percentage and the fourth percentage are 5% for the third width h 3. The backlight module 100 sequentially comprises a light source 1, a first brightness enhancement film 301, a second brightness enhancement film 302, a light homogenizing layer 2, a wavelength selective layer 4, a wavelength conversion layer 5, a prism film 61 and a reflective polarizer 62 along a second direction D2.

The conditions for test group 3 were set as follows: the backlight module comprises a single brightness enhancement film 3, the structure of the brightness enhancement film 3 is shown in fig. 4, the thickness of a substrate 31 is 0.50mm, materials of a first prism T1 and a second prism T2 are BK7 glass, the ratio of a first length w1, a second length w2 and a third length w3, w1:w2:w3, is 1:98:1, the structure of a transparent reflection layer 33 in the brightness enhancement film 3 is shown in fig. 8, the first percentage and the third percentage met by a second width h2 are 1%, and the second percentage and the fourth percentage met by a third width h3 are 1%. The backlight module 100 sequentially comprises a light source 1, a light homogenizing layer 2, a wavelength selecting layer 4, a wavelength converting layer 5, a brightness enhancing structure film 3, a prism film 61 and a reflective polarizer 62 along a second direction D2.

The conditions for test group 4 were set as follows: the backlight module comprises a single brightness enhancement film 3, the structure of the brightness enhancement film 3 is shown in fig. 4, and the substrate thereof is shown as follows31 is 0.50mm thick, and the first prism T1 and the second prism T2 are made of SiO ₂ The ratio w1:w2:w3 of the first length w1, the second length w2 and the third length w3 is 5:90:5, and the structure of the transflective layer 33 in the brightness enhancing structural film 3 is shown in fig. 8, wherein the first percentage and the third percentage are 1% for the second width h2, and the second percentage and the fourth percentage are 1% for the third width h 3. The backlight module 100 sequentially includes a light source 1, a brightness enhancement film 3, a light homogenizing layer 2, a wavelength selective layer 4, a wavelength conversion layer 5, a prism film 61, and a reflective polarizer 62 along a second direction D2.

The conditions for test group 5 were set as follows: the backlight module comprises a single brightness enhancement film 3, the structure of the brightness enhancement film 3 is shown in fig. 4, the thickness of a substrate 31 is 0.50mm, materials of a first prism T1 and a second prism T2 are BK7 glass, the ratio of a first length w1, a second length w2 and a third length w3, w1:w2:w3, is 10:80:10, the structure of a transparent reflection layer 33 in the brightness enhancement film 3 is shown in fig. 8, the first percentage and the third percentage met by a second width h2 are 1%, and the second percentage and the fourth percentage met by a third width h3 are 1%. The backlight module 100 sequentially comprises a light source 1, a light homogenizing layer 2, a wavelength selecting layer 4, a wavelength converting layer 5, a brightness enhancing structure film 3, a prism film 61 and a reflective polarizer 62 along a second direction D2.

The backlight module of the comparison group 1 is not provided with the brightness enhancement structure film 3. The backlight module 100 sequentially includes a light source 1, a light homogenizing layer 2, a wavelength selecting layer 4, a wavelength converting layer 5, a prism film 61, and a reflective polarizer 62 along a second direction D2.

The conditions for comparative group 2 were set as follows: the backlight module comprises two brightness enhancement structure films 3, the two brightness enhancement structure films 3 comprise a first brightness enhancement structure film 301 and a second brightness enhancement structure film 301, the structures of the first brightness enhancement structure film 301 and the second brightness enhancement structure film 302 are shown in fig. 4, the arrangement mode of the two brightness enhancement structure films 3 is shown in fig. 7, in each brightness enhancement structure film 3, the thickness of a substrate 31 is 0.5mm, the materials of a first prism T1 and a second prism T2 are Polycarbonate (abbreviated as PC), the ratio w1 of the first length w1, the second length w2 and the third length w3 is 1:98:1, the structure of a transparent reflection layer 33 in the brightness enhancement structure film 3 is shown in fig. 8, the first percentage and the third percentage met by the second width h2 are 1%, and the second percentage and the fourth percentage met by the third width h3 are 1%. The backlight module 100 sequentially comprises a light source 1, a first brightness enhancement structure film 301, a light homogenizing layer 2, a wavelength selective layer 4, a wavelength conversion layer 5, a second brightness enhancement structure film 302, a prism film 61 and a reflective polarizer 62 along a second direction D2.

Data0 represents brightness of other regions except the interval region BB in the display region AA; data1 represents the luminance of the first and second spaced regions BB1 and BB2, each of the first and second spaced regions BB1 and BB2 having a width q1=3 mm, η1 represents the percentage of the luminance of the first or second spaced region BB1 or BB2 to the luminance of the other region of the display region AA than the spaced region BB, η1=data1/Data 0, and a larger η1 represents a higher luminance of the first or second spaced region BB1 or BB 2; data2 represents the luminance of the third and fourth interval regions BB3 and BB4, each of the third and fourth interval regions BB3 and BB4 has a width q2=3 mm, η2 represents the percentage of the luminance of the third or fourth interval region BB3 or BB4 to the luminance of the other region of the display region AA than the interval region BB, η2=data2/Data 0, and a larger η2 represents a higher luminance of the third and fourth interval regions BB3 and BB 4.

The test results of comparative test groups 1 to 5 and comparative group 1 are as follows: the brightness enhancement structure film 3 can improve the brightness of the light emitting brightness of the interval area BB, thereby being beneficial to improving the dark band phenomenon and improving the light emitting uniformity of the backlight module; the test results of test group 1 and test group 3 were compared to each other to determine: the brightness of the light-emitting brightness of the interval area BB can be improved to a greater extent by arranging two layers of brightness enhancement structural films 3; the test results of test group 3 and test group 5 were compared to each other to determine: the smaller the inclination degree of the transflective layer 33, that is, the smaller the w1:w2:w3 is within a set range (1:98:1 to 10:80:10), the greater the degree of improvement of the brightness of the interval region BB is; the arrangement density of the reflective portions R in the transflective layer 33 and the material of the substrate 31 are required to be set according to the circumstances.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the following claims be interpreted as including the preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

Claims

1. A backlight module, comprising:

a light source;

2. The backlight module according to claim 1, wherein the substrate comprises a first prism, a second prism and a third prism sequentially arranged along a first direction;

3. The backlight module of claim 2, wherein the first and second transflective layers are parallel to each other.

4. The backlight module according to claim 2, wherein a distance between the first and second transflective layers in the first direction is gradually increased along a second direction, the second direction being a direction perpendicular to the light incident surface and directed from the light incident surface to the light emitting surface.

5. The backlight module according to claim 3 or 4, wherein a length of the orthographic projection of the first transflective layer on the light incident surface in the first direction is a first length, a minimum distance between the first transflective layer and the second transflective layer in the first direction is a second length, a length of the orthographic projection of the second transflective layer on the light incident surface in the first direction is a third length, and a ratio of the first length, the second length and the third length ranges from 1:98:1 to 10:80:10.

6. The backlight module according to claim 3 or 4, wherein the transflective layer comprises a plurality of light reflecting portions arranged in an array, and a space is provided between adjacent light reflecting portions;

7. A backlight module according to claim 6, further comprising: the reflection frame surrounds the at least one brightness enhancement structure film, and the reflection frame is used for reflecting light rays transmitted at intervals of the reflection part to one side deviating from the light source.

8. A backlight module according to claim 4, wherein the transflector is integrally provided.

9. The backlight module according to claim 5, wherein a maximum length of the first prism is smaller than a maximum length of the second prism in the first direction, and the maximum length of the second prism is larger than the maximum length of the third prism.

10. The backlight module according to claim 9, wherein a maximum length of the first prism is equal to a maximum length of the third prism in the first direction.

11. A backlight module according to any one of claims 1 to 4, wherein the material used for the transflective layer comprises a metallic material comprising one or more of silver or aluminum.

12. A backlight module according to any one of claims 1 to 4, wherein the substrate comprises one or more of tantalum pentoxide, silicon dioxide or borosilicate crown glass.

13. The backlight module of claim 1, wherein the backlight module comprises two brightness enhancing structural films; the two brightness enhancement films comprise a first brightness enhancement film and a second brightness enhancement film, and the second brightness enhancement film is positioned at one side of the first brightness enhancement film away from the light source;

14. A display device comprising a display panel and a backlight module according to any one of claims 1 to 13, the display panel being located on a light exit side of the backlight module.