CN110488533B

CN110488533B - Backlight module

Info

Publication number: CN110488533B
Application number: CN201910710656.5A
Authority: CN
Inventors: 杨勇
Original assignee: Wuhan China Star Optoelectronics Technology Co Ltd
Current assignee: Wuhan China Star Optoelectronics Technology Co Ltd
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2022-02-22
Anticipated expiration: 2039-08-02
Also published as: CN110488533A

Abstract

The invention provides a backlight module, which comprises a back plate, a light source, a light guide column and an optical membrane, wherein the back plate forms an accommodating cavity; the light source is positioned in the accommodating cavity and arranged on the bottom surface of the back plate, the light source comprises at least two spliced LED lamp strips, and the LED lamp strips comprise first LED lamps positioned in a splicing area; the optical film comprises a diffusion sheet, and the diffusion sheet is positioned in the accommodating cavity and arranged in the light emergent direction of the light source; the light guide column is arranged in the splicing region and is positioned in the light emitting direction of the light source, the light emitting surface of the light guide column corresponds to the light incident surface of the diffusion sheet, the light guide column is of a hollow structure, and the inner wall of the light guide column is provided with a reflecting film. Through set up the leaded light post on the first LED lamp in concatenation area, the light that first LED lamp sent gets into the leaded light post, via the reflectance of reflectance coating, in the diffusion piece of conduction to optical film piece, the light transverse conduction realizes even mixed light in the diffusion piece to guarantee the homogeneity of concatenation department luminance, improved the phenomenon that concatenation department produced the concatenation dark line.

Description

Backlight module

Technical Field

The invention relates to the technical field of display, in particular to a backlight module.

Background

The mini light emitting diode (MiniLED) is considered as a new generation of display technology because of its self-luminescence, small size, light weight, high brightness, longer lifetime, lower power consumption, faster response time, and higher controllability.

The size of the MiniLED lamp plate is usually smaller, and the MiniLED backlight module is manufactured in a mode of splicing a plurality of MiniLED lamp plates in a medium-size display device. However, the adjacent MiniLED lamp panels are easy to produce obvious splicing gaps at the splicing positions, splicing dark lines can exist during display, and the splicing dark lines are not easy to eliminate, so that the display image quality is influenced.

Therefore, the existing MiniLED backlight module has the technical problem that the splicing dark line is generated at the splicing position of the lamp panels, and needs to be improved.

Disclosure of Invention

The invention provides a backlight module, which aims to solve the technical problem that splicing dark lines are generated at the splicing position of a lamp panel in the conventional MiniLED backlight module.

In order to solve the above problems, the technical scheme provided by the invention is as follows:

the invention provides a backlight module, comprising:

a back plate forming a receiving cavity;

the light source is positioned in the accommodating cavity and arranged on the bottom surface of the back plate, the light source comprises at least two spliced LED lamp bars, and the LED lamp bars comprise first LED lamps positioned in a splicing area;

the optical film comprises a diffusion sheet, the diffusion sheet is positioned in the accommodating cavity and is arranged in the light emergent direction of the light source;

the light guide columns are arranged in the splicing areas and located in the light emitting direction of the light source, the light emitting surfaces of the light guide columns correspond to the light incident surfaces of the diffusion sheets, the light guide columns are of hollow structures, and the inner walls of the light guide columns are provided with reflecting films.

In the backlight module, the light guide column is funnel-shaped and comprises a first inverted circular truncated cone-shaped part and a second cylindrical part, the diffusion sheet is arranged on the first part, and the second part is arranged on the LED light bar.

In the backlight module of the invention, the opening angle of the first part is 130 to 160 degrees.

In the backlight module of the invention, the inner diameter of the second part is greater than or equal to the length of the first LED lamp.

In the backlight module of the invention, the light guide column is made of silica gel.

In the backlight module, the LED lamp strip further comprises a second LED lamp, and the backlight module further comprises a support column, wherein the support column is arranged on the LED lamp strip and is positioned in an area where the first LED lamp and the second LED lamp are not arranged.

In the backlight module of the invention, the height of the light guide column is equal to that of the support column.

In the backlight module of the invention, the support columns are made of transparent materials.

In the backlight module of the invention, the support columns are solid cylinders.

In the backlight module of the invention, the material of the reflecting film is at least one of metal and insulating material.

The invention has the beneficial effects that: the invention provides a backlight module, which comprises a back plate, a light source, a light guide column and an optical membrane, wherein the back plate forms an accommodating cavity; the light source is positioned in the accommodating cavity and arranged on the bottom surface of the back plate, the light source comprises at least two spliced LED lamp bars, and the LED lamp bars comprise first LED lamps positioned in a splicing area; the optical film comprises a diffusion sheet, and the diffusion sheet is positioned in the accommodating cavity and is arranged in the light outgoing direction of the light source; the light guide column is arranged in the splicing area and is positioned in the light emitting direction of the light source, the light emitting surface of the light guide column corresponds to the light incident surface of the diffusion sheet, the light guide column is of a hollow structure, and the inner wall of the light guide column is provided with a reflecting film. Through set up the leaded light post on the first LED lamp in concatenation area, the light that first LED lamp sent gets into the leaded light post, via the reflectance of reflectance coating, in the diffusion piece of conduction to optical film piece, the light transverse conduction realizes even mixed light in the diffusion piece to guarantee the homogeneity of concatenation department luminance, improved the phenomenon that concatenation department produced the concatenation dark line.

Drawings

In order to illustrate the embodiments or the technical solutions in the prior art more clearly, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the invention, and it is obvious for a person skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic view of a first structure of a backlight module according to an embodiment of the invention;

fig. 2 is a schematic view of a first structure of a light guide pillar in a backlight module according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of a second structure of a light guide pillar in a backlight module according to an embodiment of the present invention;

FIG. 4 is a schematic view of a third structure of a light guide pillar in a backlight module according to an embodiment of the present invention;

fig. 5 is a schematic view of a propagation path of light emitted by a first LED lamp in the backlight module according to the embodiment of the invention;

fig. 6 is a schematic view of a second structure of the backlight module according to the embodiment of the invention;

fig. 7 is a schematic flow chart illustrating a method for manufacturing a backlight module according to an embodiment of the invention;

fig. 8 is a schematic view of a manufacturing process of a light guide pillar in the method for manufacturing a backlight module according to the embodiment of the invention.

Detailed Description

The following description of the various embodiments refers to the accompanying drawings that illustrate specific embodiments in which the invention may be practiced. The directional terms mentioned in the present invention, such as [ upper ], [ lower ], [ front ], [ rear ], [ left ], [ right ], [ inner ], [ outer ], [ side ], are only referring to the directions of the attached drawings. Accordingly, the directional terms used are used for explanation and understanding of the present invention, and are not used for limiting the present invention. In the drawings, elements having similar structures are denoted by the same reference numerals.

The invention provides a backlight module and a preparation method of the backlight module, which are used for relieving the technical problem that splicing dark lines are generated at the splicing position of a lamp panel in the conventional MiniLED backlight module.

Fig. 1 is a schematic view of a first structure of a backlight module according to an embodiment of the invention. The backlight module comprises a back plate 10, a light source 20, a light guide column 30 and an optical film 50.

The backboard 10 is formed to hold the chamber, and the light source 20 is located and holds the intracavity, and sets up on the bottom plate of backboard 10, and the light source 20 includes the LED lamp strip 21 of two at least concatenation settings, and LED lamp strip 21 is including being located the regional first LED lamp 221 of concatenation.

The optical film 50 includes a diffusion sheet 51, and the diffusion sheet 51 is located in the accommodating chamber and disposed in the light exit direction of the light source 20.

The light guide columns 30 are disposed in the splicing region and located in the light emitting direction of the light source 20, the light emitting surfaces of the light guide columns 30 correspond to the light incident surfaces of the diffusion sheets 51, the light guide columns 30 are hollow, and the inner walls of the light guide columns 30 are provided with reflective films (not shown).

The backlight module of the present invention is a direct type backlight module, the back plate 10 forms a receiving cavity, and the light source 20 is directly disposed on the bottom plate of the back plate 10.

The light source 20 includes at least two LED light bars 21 arranged in a splicing manner, the LED light bars 21 are provided with LED lamps 22, and the LED lamps 22 include first LED lamps 221 located in a splicing region. Because the size of the LED light bars 21 is small, when the LED light bars 21 are used as a light source, the plurality of LED light bars 21 need to be spliced together for use, and the light source 20 formed by splicing comprises a plurality of splicing areas, wherein the splicing areas are areas where the splicing seams of two adjacent LED light bars 21 are located, and the areas can include one row of first LED lights 221 or a plurality of rows of first LED lights 221.

In one embodiment, the LED light bars 21 further include second LED lights 222, the second LED lights 222 are located between adjacent splicing regions, and a plurality of rows of the second LED lights 222 can be disposed on each LED light bar 21.

The LED lamp 22 is a mini light emitting diode (MiniLED), which is considered as a new generation of display technology due to its self-luminescence, small size, light weight, high brightness, longer lifetime, lower power consumption, faster response time, and higher controllability.

The optical film 50 is disposed in the accommodating chamber and located in the light emitting direction of the light source 20, and generally includes a diffusion sheet 51, a prism sheet 52, and a reflection type polarization enhancement film 53, which are stacked.

The diffusion sheet 51 is generally made of a PET (polyethylene terephthalate) or PC (polycarbonate) substrate, and has a smooth front surface and a rough back surface. Because the diffusion sheet 51 has diffusion particles, the diffusion particles can uniformly transmit light in the film, so as to achieve the purpose of uniform light mixing, the light emitted by the light source 20 enters the diffusion sheet 51 to be refracted, reflected and scattered for multiple times, and the light is transversely transmitted in the diffusion sheet 51, so that the backlight is more uniform.

The prism sheet 52 is a light condensing means for condensing the dispersed light to a certain angle range to be emitted by using the law of total reflection and refraction, thereby increasing the brightness in the emission range.

The reflective polarizing brightness enhancement film 53 may also enhance the brightness of the backlight.

The light guide column 30 is disposed in the splicing region and located in the light emitting direction of the light source 20, the light emitting surface of the light guide column 30 corresponds to the light incident surface of the diffusion sheet 51, and the light incident surface of the light guide column 30 corresponds to the first LED lamp 221.

The light guide column 30 is a hollow structure, the light emitted from the first LED lamp 221 enters the inside of the light guide column 30, and since the inner wall is provided with the reflective film, the light emitted from the first LED lamp 221 does not emit to the outside of the light guide column 30, and reaches the diffusion sheet 51 above after being reflected for many times on the inner wall.

The light passes through the diffusion sheet 51, is laterally transmitted through the diffusion sheet 51, passes through the prism sheet 52 and the reflection-type polarization enhancement film 53 above, and finally is uniformly mixed in the optical film 50.

The size of the existing MiniLED lamp plate is usually smaller, and the MiniLED backlight module in the middle-size display device is manufactured in a mode of splicing a plurality of MiniLED lamp plates. However, the light that adjacent miniLED lamp plate sent at the LED lamp in the splice area is difficult to directly intersect at the concatenation department, therefore the concatenation department easily produces comparatively obvious concatenation gap, can have the concatenation dark line and be difficult for eliminating when showing, influences and shows the picture quality.

Therefore, the existing MiniLED backlight module has the technical problem that splicing dark lines are generated at the splicing positions of the lamp panels.

According to the invention, the light guide column 30 is arranged on the first LED lamp 221 in the splicing area, light emitted by the first LED lamp 221 enters the light guide column 30, is reflected by the reflecting film and is transmitted to the diffusion sheet 51 in the optical film 50, and light is transversely transmitted in the diffusion sheet 51, so that uniform light mixing of all positions of the whole optical film 50 is finally realized, the uniformity of brightness at the splicing position is ensured, and the phenomenon of splicing dark lines at the splicing position is improved.

The light guide column 30 is disposed on the LED light bar 21 and corresponds to an area where the first LED light 221 is disposed. The light guide pillar 30 mainly plays a role of guiding light emitted from the first LED lamp 221 to the optical film 50, and the shape of the light guide pillar 30 may be various.

In one embodiment, as shown in fig. 2, the light guiding pillar 30 is shaped like a funnel and includes a first portion 31 with a truncated cone shape and a second portion 32 with a cylindrical shape, the optical film 50 is disposed on the first portion 31, the second portion 32 is disposed on the LED light bar 21, and light emitted from the first LED lamp 221 passes through the second portion 32 and the first portion 31 and finally enters the optical film 50.

The light guide bar 30 has a hollow structure and includes an outer wall 301 and an inner wall 302, wherein the inner wall 302 is coated or sputtered with a reflective film (not shown), the reflective film is a high-reflectivity film layer, and the material of the reflective film may be at least one of metal and an insulating material, and the insulating material may be silicon oxide or nitrogen oxide. The light emitted from the first LED lamp 221 enters the light guide column 30, is reflected on the reflective film multiple times, and enters the optical film 50.

The first part 31 is in a shape of an inverted frustum, the inner diameter of the light-emitting surface is R, and the inner diameter of the light-entering surface is R; the second portion 32 is cylindrical, and the inner diameters of the light emergent surface and the light incident surface are both R, and R is greater than R.

When the light guide bar 30 is in a funnel-shaped structure, the light propagation diagram is as shown in fig. 5, the light 220 emitted by the first LED lamp 221 firstly passes through the second portion 32, and after multiple reflections in the second portion 32, the light 220 fills the second portion 32, and then enters the first portion 31, and after multiple reflections, the light 220 fills the first portion 31. Because the inner diameter R of the light-emitting surface of the first portion 31 is larger, the incident surface of the incident light entering the diffusion sheet 51 is increased, so that the transverse propagation of the light in the diffusion sheet 51 is easier to achieve, and then the light enters other film layers of the optical film 50, so that the whole backlight is more uniform and the effect is better.

In one embodiment, the opening angle a of the first portion 31 is 130 to 160 degrees. The angle can ensure that the light-emitting light shape of the light guide column 30 is substantially the same as the light-emitting light shape of the first LED lamp 221.

In an embodiment, the inner diameter r of the second portion 32 is greater than or equal to the length of the first LED lamp 221, so that the light guide pillar 30 can completely cover the area above the first LED lamp 221, and the light emitted from the first LED lamp 221 can completely enter the light guide pillar 30 as much as possible, thereby improving the light utilization rate.

In one embodiment, the height H of the light guide 30 is 0.1 to 0.2 mm, and the wall thickness b of the light guide 30 is 100 to 500 μm, so that the light guide 30 can support the optical film 50 thereon.

As shown in fig. 1, the light source 20 further includes a packaging adhesive 23, and the packaging adhesive 23 is disposed on the LED light bar 21 and covers the first LED lamp 221 and the second LED lamp 222. The LED lamp 22 in fig. 1 is packaged by a Chip On Board (COB) method, and the packaging adhesive 23 is disposed On the LED light bar 21 in a whole layer and extends to cover all the LED lamps 22.

Of course, the present invention is not limited thereto, and as shown in fig. 6, each LED lamp 22 is individually packaged by the packaging adhesive 23 in a Chip Scale Package (CSP) manner. The arrangement of the light guide column 30 in the present invention is suitable for both of these two packaging methods.

In an embodiment, the material of the light guide pillar 30 is the same as the material of the packaging adhesive 23, and the light guide pillar 30 and the packaging adhesive 23 are bonded together by a baking and curing process, and the same material can ensure that the light guide pillar 30 and the packaging adhesive have better adhesive force in the process forming.

In one embodiment, the light guide bar 30 is made of silicone.

FIG. 3 is a schematic diagram showing a second shape of the light guide bar 30. The light guide column 30 is a whole and shaped like a hollow truncated cone, and the inner diameter R of the light incident surface is smaller than the inner diameter R of the light emitting surface. The structure transmits the light emitted by the first LED lamp 221 below to the diffusion sheet 51 above, and the light is transmitted in the diffusion sheet 51 transversely, so that uniform light mixing at all positions in the diffusion sheet 51 is realized, splicing dark lines at splicing positions are eliminated, and uneven display at the splicing positions is improved. The circular truncated cone-shaped light guide column 30 increases the light emitting area, so that the light mixing effect is better.

FIG. 4 is a schematic diagram showing a third shape structure of the light guide bar 30. The light guide 30 is a unitary body having a hollow cylindrical shape. The inner diameter r of the light incident surface is equal to the inner diameter r of the light emergent surface. The structure can also transmit the light emitted by the first LED lamp 221 below to the diffusion sheet 51 above, and the light is transmitted transversely in the diffusion sheet 51, so that uniform light mixing is realized, splicing dark lines at splicing positions are eliminated, and uneven display at the splicing positions is improved.

As shown in fig. 1 and fig. 6, in an embodiment, the backlight module further includes a supporting pillar 40, and the supporting pillar 40 is disposed on the LED light bar 21 and corresponds to an area where the first LED lamp 221 and the second LED lamp 222 are not disposed.

The supporting posts 40 have the same height as the light guide posts 30 and are solid structures made of transparent materials. The shape of the support posts 40 may be the same as or different from the light guide posts 30. In one embodiment, the support posts 41 are solid cylinders.

The support posts 40 are disposed on the LED light bars 21 and far away from the splicing region, and mainly support the optical film 50 above the support posts. In addition, the support columns 40 are disposed corresponding to the regions where the first LED lamp 221 and the second LED lamp 222 are not disposed, that is, disposed between the adjacent LED lamps 22, so that loss of light efficiency of the LED lamps 22 above the LED lamps 22 can be avoided.

As shown in fig. 7, the present invention further provides a method for manufacturing a backlight module, the method comprising the steps of:

s1: preparing a back plate, and forming a containing cavity in the back plate.

S2: the light source is provided and comprises at least two LED lamp strips which are spliced, and the LED lamp strips comprise first LED lamps located in splicing areas.

S3: the light guide column is of a hollow structure and arranged in the splicing region, the light guide column is located in the light emitting direction of the light source, and the inner wall of the light guide column is provided with a reflecting film.

S4: set up light source and leaded light post in holding the intracavity, the light source setting is on the bottom surface of backplate.

S5: an optical film is arranged in the accommodating cavity and comprises a diffusion sheet, and the light incident surface of the diffusion sheet corresponds to the light emergent surface of the light guide column.

The method is specifically described below with reference to fig. 1 to 8.

In S1, the back sheet 10 is prepared, and a receiving cavity is formed in the back sheet 10. The structure of the back sheet 10 is shown in fig. 1. The backlight module is a direct type backlight module, and the back plate 10 comprises a bottom plate and side plates, and each plate is enclosed to form an accommodating cavity.

In S2, a light source 20 is provided, the light source 20 including at least two LED light bars 21 arranged in a tiled arrangement, the LED light bars 21 including a first LED light 22 located in the tiled area. The structure of the light source 20 is shown in fig. 1 or fig. 6.

Because the size of the LED light bars 21 is small, when the LED light bars 21 are used as a light source, the plurality of LED light bars 21 need to be spliced together for use, and the light source 20 formed by splicing comprises a plurality of splicing areas, wherein the splicing areas are areas where the splicing seams of two adjacent LED light bars 21 are located, and the areas can include one row of first LED lights 221 or a plurality of rows of first LED lights 221.

In S3, the light guide bar 30 having a hollow structure is disposed in the splicing region, the light guide bar 30 is located in the light emitting direction of the light source 20, and the inner wall of the light guide bar 30 is provided with a reflective film.

The light guide column 30 is arranged on the LED light bar 21 and corresponds to the splicing area. The light guide column 30 is of a hollow structure, light emitted by the first LED lamp 221 enters the inside of the light guide column 30, and due to the fact that the reflecting film is arranged on the inner wall, the light emitted by the first LED lamp 221 cannot be emitted to the outside of the light guide column 30, and reaches the optical film above through multiple reflections on the inner wall.

The preparation process of the light guide bar 30 is shown in fig. 8, and specifically includes the following steps:

s31: a light guide material layer 100 is prepared.

As shown in a of fig. 8, a light guide material layer 100 is prepared, and the light guide material layer 100 is made of silica gel, and can be prepared by using a silica gel film forming process.

S32: a reflective film 200 is formed on the light guide material layer 100.

As shown in b of fig. 8, a reflective film 200 is formed on the light guide material 100. The reflective film 200 is a high-reflectivity film, and the material thereof may be at least one of metal and insulating material, and the insulating material may be silicon oxide, nitrogen oxide, or the like. The reflective film 200 is formed on the light guide material 100 by coating or sputtering.

S33: the light guide material layer 100 and the reflective film 200 are cut to form a plurality of independent light guide units 300, the light guide units 300 are formed into the light guide column 30 with a hollow structure through curling and curing, the reflective film 200 is located on the inner wall of the light guide column 30, and the light guide material layer 100 is located on the outer wall of the light guide column 30.

As shown in c of fig. 8, the light guide material layer 100 and the reflective film 200 are longitudinally cut through a cutting process to form a plurality of independent light guide units 300, each light guide unit 300 including the light guide material layer 100 and the reflective film 200.

As shown in d of fig. 8, the light guide unit 300 is formed by winding and curing to form the light guide bar 30 having a hollow structure. When the light guide material layer 100 is curled, the reflective film 200 is curled inward, the reflective film 200 is wrapped inside, and in the finally formed light guide column 30, the reflective film 200 is located on the inner wall of the light guide column 30, and the light guide material layer 100 is located on the outer wall of the light guide column 30.

S34: and transferring the light guide column 30 to a splicing area on the LED light bar 21, and baking and curing.

As shown in e in fig. 8, after the light guide plate 30 is prepared, the light guide column 30 is transferred to the splicing region on the surface of the LED light bar 21, corresponds to the first LED lamp 221, and is formed through a baking and curing process.

In one embodiment, as shown in fig. 1, the light source 20 further includes an encapsulation adhesive 23, and the encapsulation adhesive 23 is disposed on the LED light bar 21 and covers the first LED lamp 221 and the second LED lamp 222. The LED lamp 22 in fig. 1 is packaged by a Chip On Board (COB) method, and the packaging adhesive 23 is disposed On the LED light bar 21 in a whole layer and extends to cover all the LED lamps 22.

As shown in e in fig. 8, the material of the light guide bar 30 is the same as the material of the packaging adhesive 23, and the light guide bar 30 and the packaging adhesive 23 are bonded together by baking and curing. The same material can ensure that the two have better adhesive force in the process molding.

In one embodiment, the backlight module further includes a supporting pillar 40, and the supporting pillar 40 is disposed on the LED light bar 21 and corresponds to an area where the first LED lamp 221 and the second LED lamp 222 are not disposed.

The height of the support column 40 is the same as that of the light guide column 30, and the support column 40 is a solid structure made of a transparent material and can be directly molded when being prepared. The shape of the support posts 40 may be the same as or different from the light guide posts 30. In one embodiment, the support posts 41 are solid cylinders.

The support column 40 is arranged on the LED light bar 21 and far away from the splicing area, and mainly plays a role in supporting the upper diaphragm. In addition, the support columns 40 are disposed corresponding to the regions where the first LED lamp 221 and the second LED lamp 222 are not disposed, that is, disposed between the adjacent LED lamps 22, so that loss of light efficiency of the LED lamps 22 above the LED lamps 22 can be avoided.

Through the above steps, the light guide bar 30 is prepared on the light source 20.

In S4, the light source 20 and the light guide bar 30 are disposed in the receiving cavity, and the light source 20 is disposed on the bottom surface of the back sheet 10.

As shown in FIG. 1, the light guide 30 is bonded to the light source 20 and placed together on the bottom surface of the back sheet 10 with both in the receiving cavity.

In S5, the optical film 50 is disposed in the accommodating cavity, the optical film 50 includes a diffusion sheet 51, and a light incident surface of the diffusion sheet 51 corresponds to a light emitting surface of the light guide bar 30.

As shown in FIG. 1, an optical film 50 is disposed on the light guide 30, and the optical film 50 is also located within the receiving cavity. The optical film 50 generally includes a diffusion sheet 51, a prism sheet 52, and a reflection type polarization enhancement film 53, which are stacked.

The diffusion sheet 51 is generally made of a PET (polyethylene terephthalate) or PC (polycarbonate) substrate, and has a smooth front surface and a rough back surface. Because the diffusion sheet 51 has diffusion particles, the diffusion particles can uniformly transmit light in the film, so as to achieve the purpose of uniform light mixing, the light emitted from the light guide column 30 enters the diffusion sheet 51 to be refracted, reflected and scattered for multiple times, and the light is transversely transmitted in the diffusion sheet 51, so that the backlight is more uniform.

When the light passes through the optical film 50, the light passes through the diffusion sheet 51, is laterally transmitted through the diffusion sheet 51, and then passes through the prism sheet 52 and the reflection-type polarization enhancement film 53 above, so that uniform light mixing in the optical film 50 is finally realized.

The size of the existing MiniLED lamp plate is usually smaller, and the MiniLED backlight module in the middle-size display device is manufactured in a mode of splicing a plurality of MiniLED lamp plates. However, the adjacent MiniLED lamp panels are easy to produce obvious splicing gaps at the splicing positions, splicing dark lines can exist during display, and the splicing dark lines are not easy to eliminate, so that the display image quality is influenced.

Therefore, the existing miniLED backlight module has the technical problem that the splicing dark line is generated at the splicing position of the lamp panels.

The light guide column 30 is arranged on the LED light bar 21 and corresponds to the splicing area. The light guide pillar 30 mainly plays a role of guiding light emitted from the first LED lamp 221 to the optical film 50, and the shape of the light guide pillar 30 may be various.

In one embodiment, as shown in fig. 2, the light guide pillar 30 is shaped like a funnel and includes a first portion 31 having a truncated cone shape and a second portion 32 having a cylindrical shape, the optical film 50 is disposed on the first portion 31, the second portion 32 is disposed on the LED light bar 21, and light emitted from the first LED light 221 passes through the second portion 32 and the first portion 31 and finally enters the diffusion sheet 51.

The light guide pillar 30 has a hollow structure, and includes an outer wall 301 and an inner wall 302, wherein the inner wall 302 is coated or sputtered with a reflective film, the reflective film is a high-reflectivity film layer, the material of the reflective film may be at least one of metal and an insulating material, and the insulating material may be silicon oxide or nitrogen oxide. The light emitted from the first LED lamp 221 enters the light guide bar 30, is reflected on the reflective film a plurality of times, and enters the diffusion sheet 51.

When the light guide bar 30 is in a funnel-shaped structure, the light propagation diagram is as shown in fig. 5, the light 220 emitted by the first LED lamp 221 firstly passes through the second portion 32, and after multiple reflections in the second portion 32, the light 220 fills the second portion 32, and then enters the first portion 31, and after multiple reflections, the light 220 fills the first portion 31. Because the inner diameter R of the light-emitting surface of the first portion 31 is larger, the incident surface of the incident light entering the diffusion sheet 51 is increased, and the transverse propagation of the light in the diffusion sheet 51 is easier to realize, so that the backlight is more uniform and the effect is better.

FIG. 3 is a schematic diagram showing a second shape of the light guide bar 30. The light guide column 30 is a whole and shaped like a hollow truncated cone, and the inner diameter R of the light incident surface is smaller than the inner diameter R of the light emitting surface. The structure transmits the light emitted by the first LED lamp 221 below to the diffusion sheet 51 above, and the light is transversely transmitted in the diffusion sheet 51, so that uniform light mixing is realized, splicing dark lines at splicing positions are eliminated, and uneven display at the splicing positions is improved. The circular truncated cone-shaped light guide column 30 increases the light emitting area, so that the light mixing effect is better.

According to the above embodiments:

In summary, although the present invention has been described with reference to the preferred embodiments, the above-described preferred embodiments are not intended to limit the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, therefore, the scope of the present invention shall be determined by the appended claims.

Claims

1. A backlight module, comprising:

a back plate forming a receiving cavity;

the light guide column is arranged in the splicing region and located in the light emitting direction of the light source, the light emitting surface of the light guide column corresponds to the light incident surface of the diffusion sheet, the light guide column is of a hollow structure, the inner wall of the light guide column is provided with a reflecting film, the light guide column is arranged on the LED light bar and is correspondingly provided with the region of the first LED lamp.

2. The backlight module of claim 1, wherein the light guide pillar is funnel-shaped and comprises a first portion with a truncated cone shape and a second portion with a cylindrical shape, the diffusion sheet is disposed on the first portion, and the second portion is disposed on the LED light bar.

3. The backlight module as claimed in claim 2, wherein the opening angle of the first portion is 130 to 160 degrees.

4. The backlight module of claim 2, wherein an inner diameter of the second portion is greater than or equal to a length of the first LED lamp.

5. The backlight module as claimed in claim 1, wherein the light guide pillar is made of silicone.

6. The backlight module of claim 1, wherein the LED light bar further comprises a second LED light, and the backlight module further comprises a support post disposed on the LED light bar in an area where the first LED light and the second LED light are not disposed.

7. The backlight module of claim 6, wherein the height of the light guide posts is equal to the height of the support posts.

8. The backlight module of claim 6, wherein the material of the support posts is a transparent material.

9. The backlight module of claim 6, wherein the support posts are shaped as solid cylinders.

10. The backlight module of claim 1, wherein the reflective film is made of at least one of a metal and an insulating material.