CN106681052B - A kind of backlight module and display device - Google Patents

Abstract

The invention provides a backlight module and a display device, which belong to the field of display technology and can solve the problem that the existing backlight module cannot realize narrow frame and ultra-thin display at the same time. In the backlight module of the present invention, the light source is embedded in the first lens structure, the first lens structure is arranged on the first surface of the plate body, and the second lens structure is arranged on the light-emitting surface of the plate body, so that the first lens structure and Combination of the second lens structure: the first lens structure shields the light source point from the front view angle and disperses the light from the light source to expand the light output viewing angle; The last scattering is carried out at the second lens structure of the second lens to improve the uniformity of light intensity on the light exit surface. The light source of the backlight module of the present invention does not need to occupy the side position of the display device, and at the same time, the height of the optical cavity is effectively compressed, and the thickness of the backlight module is reduced to the greatest extent, thereby realizing a thinner and narrower frame design.

Description

A kind of backlight module and display device

technical field

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

Background technique

Most of the existing liquid crystal display devices (LCD, Liquid Crystal Display) are backlight type liquid crystal display devices, which include a liquid crystal display panel and a backlight module (backlight module). The liquid crystal display panel itself does not emit light, and needs the light source provided by the backlight module to display images normally. Therefore, the backlight module becomes one of the key components of the liquid crystal display device.

Backlight modules can be divided into side-type backlight modules and direct-type backlight modules according to the incident position of the light source. As shown in FIG. 1, the side-entry backlight module usually arranges a light source, such as an LED light bar 12, at the edge of the back panel behind the side of the liquid crystal display panel, and the light emitted by the LED light bar 12 is emitted from the light guide plate 11 (LGP, Light The light incident surface on one side of the Guide Plate) enters the light guide plate 11, and after being diffused, exits from the light exit surface of the light guide plate 11, and then passes through the optical film to form a surface light source to be provided to the liquid crystal display panel. As shown in Figure 2, the direct-type backlight module is a backlight such as a cathode fluorescent lamp (CCFL, Cold Cathode Fluorescent Lamp), or a light source 22 (generally a point light source) such as an LED lamp is arranged on the back plate 23 behind the liquid crystal panel. Above, the light is uniformized by the diffuser plate 21 to form a surface light source and supplied to the liquid crystal panel.

The inventors have found that there are at least the following problems in the prior art: the design and process conditions of the current backlight module are limited. As shown in FIG. Narrow frame design, at the same time it is difficult to achieve super large size and compatible with high-brightness design; direct-type backlight module, as shown in Figure 2, needs to reserve a certain height H of the light cavity, increasing the light mixing distance and cannot achieve a thin design.

Contents of the invention

Aiming at the problem that the existing backlight module cannot simultaneously realize narrow frame and ultra-thin display, the present invention provides a backlight module and a display device.

The technical solution adopted to solve the technical problems of the present invention is:

A backlight module, comprising:

The light-permeable plate body, wherein the light-emitting surface of the plate body is the second surface, which is opposite to the second surface

The opposite side is the first side;

a first lens structure disposed on the first surface of the board;

a light source embedded in the first lens structure;

The second lens structure is arranged on the second surface of the plate body.

Preferably, the first lens structure includes a total reflection lens, and the second lens structure includes a concave-convex lens formed by a combination of a concave lens and a convex lens.

Preferably, in a direction perpendicular to the surface where the plate body is located, the cross-section of the total reflection lens is an isosceles right triangle, and the hypotenuse of the isosceles right triangle is parallel to the surface where the plate body is located, so The right angle of the isosceles right triangle is arranged closer to the second surface of the board than the hypotenuse; the light source is embedded on the hypotenuse of the isosceles right triangle.

Preferably, the concave portion of the meniscus lens corresponds to the right-angle vertex of the isosceles right-angled triangle, and the convex portion of the meniscus lens corresponds to the position of the right-angled side of the isosceles right-angled triangle.

Preferably, the height of the isosceles right triangle is h ₁ , and the size of the plate is h ₂ in the direction perpendicular to the plane where the plate is located, and the range of h ₁ : h ₂ is (3-4.5 ): 5.

Preferably, the light source includes an LED lamp, and a reflective layer is provided on a side of the LED lamp away from the second surface.

Preferably, the first lens structure includes a total reflection lenticular lens, and each of the total reflection lenticular lenses is embedded with a plurality of LED lamps at intervals.

Preferably, a reflective sheet is provided on the side of the first surface of the plate away from the second surface.

Preferably, the plate body includes a light guide plate or a diffusion plate, and diffusion particles are arranged in the plate body.

The present invention also provides a display device, including the above-mentioned backlight module.

Wherein, the second surface in the present invention is the light-emitting surface of the plate body, and the first surface is the surface opposite to the second surface. The total reflection prism in the present invention refers to a prism whose cross section is an isosceles right triangle.

In the backlight module of the present invention, the light source is embedded in the first lens structure, the first lens structure is arranged on the first surface of the plate body, and the second lens structure is arranged on the light-emitting surface of the plate body, so that the first lens structure and Combination of the second lens structure: the first lens structure shields the light source point from the front view angle and disperses the light output of the light source to expand the light output viewing angle, and the second lens structure scatters the light emitted by the board, so that the light is refracted in the board and then on the light exit surface The last scattering is performed at the second lens structure of the second lens structure, thereby improving the uniformity of light intensity on the light exit surface. The light source of the backlight module of the present invention does not need to occupy the side position of the display device, and at the same time, the height of the optical cavity is effectively compressed, the thickness of the backlight module is reduced to the greatest extent, and a thinner and narrower frame design is realized. The backlight module of the present invention is suitable for various display devices.

Description of drawings

FIG. 1 is a schematic structural view of an existing side-entry backlight module;

FIG. 2 is a schematic structural diagram of an existing direct-lit backlight module;

3 is a schematic structural view of a backlight module according to Embodiment 1 of the present invention;

4-6 are schematic structural views of a backlight module according to Embodiment 2 of the present invention;

7 is a schematic structural view of a backlight module according to Embodiment 3 of the present invention;

Fig. 8 is a light intensity distribution curve diagram of the light source of Embodiment 3 of the present invention;

9 is a light intensity distribution curve diagram of the backlight module according to Embodiment 3 of the present invention;

10-11 are the simulation effect diagrams of the screen of the backlight module according to Embodiment 3 of the present invention;

Fig. 12 is a schematic structural diagram of a light source according to Embodiment 2 of the present invention;

13-15 are schematic diagrams of light propagation in Embodiment 2 of the present invention;

Wherein, reference signs are: 11, light guide plate; 12, LED light bar; 21, diffusion plate; 22, light source; 221, LED light; 222, reflective layer; 31, plate body; 32, first lens structure; 33 . The second lens structure; 34. The reflection sheet; 35. The printed circuit board.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example 1:

This embodiment provides a backlight module, as shown in FIG. 3 , which includes a light-transmitting plate body 31 , wherein the light-emitting surface of the plate body is the second surface, and the first surface is the surface opposite to the second surface. A first lens structure 32 is provided in the first surface of the plate body 31 (that is, the first lens structure 32 is actually embedded in the board ladder 31); the first lens structure 32 is embedded with a light source 22; A second lens structure 33 is also provided on the two surfaces.

The backlight module of this embodiment combines the first lens structure 32 and the second lens structure 33, wherein the first lens structure 32 wraps the light source 22 to shield the light source 22, that is, disperses the light emitted by the light source 22, so that from the front view angle When viewing, the light source 22 is invisible, and the viewing angle is expanded; the second lens structure 33 scatters the light emitted by the plate body 31, so that the light is refracted in the plate body 31 and then scattered at the second lens structure 33 on the light-emitting surface for the last time, thereby Improve the uniformity of light intensity on the light emitting surface.

The light source 22 of the backlight module of the present invention does not need to occupy the side position of the display device, and at the same time, the height of the optical cavity is effectively compressed, the thickness of the backlight module is reduced to the greatest extent, and a thinner and narrower frame design is realized. The backlight module is suitable for various display devices.

Example 2:

This embodiment provides a backlight module, as shown in FIG. 4 , comprising a light-transmitting plate body 31, a first lens structure 32 disposed in the first surface of the plate body 31; embedded in the first lens structure 32 the light source 22 inside; the second lens structure 33 arranged on the second surface of the plate body 31 . Wherein, the first lens structure 32 is a total reflection lens, and at the same time, the second lens structure 33 is a concave-convex lens formed by a combination of a concave lens and a convex lens.

The material of the plate body 31 can be an optical resin material, such as polymethyl methacrylate (PMMA), polycarbonate (PC), polystyrene (PS), etc.; the material of the first lens structure 32 is also a similar optical resin material . It should be noted that the refractive index of the material of the first lens structure 32 and the material of the plate body 31 may be different or the same. However, when the two are the same material and have the same refractive index, it is necessary to form an air layer or coat optical liquid optical glue (OCR) on the contact surface of the two.

Combining the comparison of Figure 2, Figure 3, and Figure 4, it can be seen that there are design limitations in the display structure shown in Figure 2, and a certain optical cavity height H needs to be reserved to increase the light mixing distance to achieve the effect of secondary light mixing. It is also necessary to increase the number of LEDs and LED lens (secondary lens) to cover the light shadow of the LED itself to improve the uniformity of the picture.

However, the present embodiment uses a total reflection lens to form a cross-section on the first surface of the plate body 31. The total reflection lens structure is an isosceles right triangle, that is, the hypotenuse of the total reflection lens is embedded in the plate body 31 after wrapping the light source 22, so that The light source 22 is shielded from the front viewing angle, so that the light emitted by the light source 22 directly enters the plate body 31 without loss.

Specifically, referring to Fig. 13: the light emitted by the adjacent light source 22 is incident on a right-angled side of the total reflection lens from the direction of the parallel plate body (shown in the figure is incident from the left side, that is, the A side, it can be understood Yes, the propagation of the incident light on the right side is similar), refraction and reflection will occur in the total reflection prism, and the light will be changed on the surface where the other right-angle side (the right side is the B side) of the total reflection prism The original direction of propagation is refracted and exits without loss.

See Figure 14: when the light emitted by the adjacent light source 22 is incident perpendicular to the surface of a right-angled side of the total reflection prism, it is equivalent to the incident angle of the light relative to the surface of the plate body is 45°, and the light is deflected by 90° without loss. The surface where the other right-angle side is located is refracted, and there is no light loss in this process; light rays from other angles undergo secondary refraction on the surface where the other right-angle side of the total reflection prism is located according to the law of refraction and reflection.

In addition, as shown in Figure 15, part of the light from the light source 22 inside the total reflection prism is incident from the side A slope of the prism, and by the working principle of the total reflection prism—the law of reflection and refraction of light, light propagates in the same medium and occurs When reflecting, the reflection angle is equal to the incident angle, and the light will not be refracted when it is incident on the other medium from one medium perpendicular to the plane of the two mediums. The light will be reversed 180° without loss. The reflective layer on the incident surface of the prism (the base or hypotenuse of the isosceles right triangle) scatters and redistributes the light; while the light from other angles will be refracted on the right-angled side of the total reflection prism, as shown in Figure 4. The light is refracted twice on the light emitting surface of the plate body 31, so as to realize the shielding effect of the total reflection prism on the light source 22 at the right angle, dilute the halo of the light source 22, and avoid the problem of uneven brightness and darkness caused by the light source 22.

This means that the first lens structure 32 can guide the light emitted by the light source 22 into the plate body 31 without loss, and at the same time transmit the light without changing the transmission direction of the light, thereby greatly improving the light extraction efficiency. At the same time, it can be seen from the figure that this structure effectively compresses the height of the optical cavity and minimizes the thickness of the backlight module. In addition, the concave-convex lens is used to scatter the light emitted from the plate body 31 to various angles, so as to improve the uniformity of light intensity on the light emitting surface.

Preferably, in the direction perpendicular to the plane where the plate body 31 is located, the cross-section of the total reflection lens is an isosceles right triangle, and the hypotenuse of the isosceles right triangle is parallel to the plane where the plate body 31 is located. , the right angle of the isosceles right triangle is arranged closer to the second surface of the plate body 31 than the hypotenuse; the light source 22 is embedded on the hypotenuse of the isosceles right triangle.

Preferably, the concave part of the meniscus lens corresponds to the position of the right angle of the isosceles right triangle, and the convex part of the meniscus lens corresponds to the position of the right angle side of the isosceles right triangle.

That is to say, as shown in Figure 4, the cross-section of the total reflection lens is an isosceles right triangle, wherein, the hypotenuse of the isosceles right triangle is positioned at the bottom of the plate body 31, and the light source 22 is embedded in its hypotenuse, so that the light emitted by the light source 22 The light exits from the right-angle side of the total reflection lens, which means that there is no light at the center of the right-angle top inside the plate body 31 , thus covering the shadow at the position of the light source 22 . It can be understood that the light output from the plate body 31 at the right-angle position is weaker than that at the right-angle side. Here, the concave-convex lens is used to scatter the light intensity at the position at the right-angle side to the right-angle position. Specifically , the concave portion corresponds to the right angle position of the isosceles right triangle to converge the light, and the convex portion corresponds to the right angle side of the isosceles right triangle to diverge the light, so as to improve the uniformity of light intensity on the light emitting surface.

Preferably, the light source 22 includes an LED lamp 221, and a reflective layer 222 is provided on a side of the LED lamp far away from the second surface.

That is to say, here the light source 22 adopts the LED lamp 221 point light source. Since the light emitting direction of the point light source itself is in all directions, the point light source with the reflective layer 222 at the bottom as shown in FIG. ) light loss.

Preferably, the first lens structure 32 includes a total reflection lenticular lens, and each of the total reflection lenticular lenses is embedded with a plurality of LED lamps at intervals.

That is to say, as shown in FIG. 5 , the first lens structure 32 is a plurality of elongated total reflection lenticular lenses, and a plurality of light sources 22 are embedded in each total reflection lenticular lens. Homogenize. Of course, as shown in FIG. 6 , a total reflection lens enclosing the light source 22 can only be provided at the position of each light source 22 . In the direction parallel to the plate body 31 , the size of the lens can be changed according to actual needs.

Example 3:

This embodiment provides a backlight module, which has a structure similar to that of the backlight module in Embodiment 2. The difference between it and Embodiment 2 is that there is no reflective layer on the back of the light source 22, and the first surface of the board body 31 is peripherally equipped with Reflector 34 is provided.

That is to say, as shown in FIG. 7 , a reflective sheet is provided outside the first surface of the plate body 31 to reduce the light loss on the first surface (ie, the back), improve the utilization rate of light, and enhance light efficiency. It should be noted that the figure also shows a printed circuit board 35 (PCB board) for providing signals to the light source 22. Generally, the PCB board is arranged under the light source 22. The shadow that shields the light source 22 mentioned above includes the PCB board shadows.

Preferably, the height of the isosceles right triangle is h ₁ , and in the direction perpendicular to the plane where the plate body 31 is located, the size of the plate body 31 is h ₂ , and the range of h ₁ : h ₂ is (3 -4.5): 5. Wherein, when the range of h ₁ :h ₂ is (3-4.5):5, the light emitting effect can be made more uniform.

A specific embodiment is given here:

As shown in Fig. ₇ , select the plate body 31 that thickness h2 is 2.5mm, the first surface (being light-incident surface) comprises columnar total reflection lenses distributed at intervals, its section is an isosceles right triangle, and height _h1 is 2.0 mm, which is equivalent to 0.5 mm from the right angle of the total reflection lens to the second surface of the plate body 31 (ie, the light-emitting surface), and the hypotenuse of the total reflection lens is embedded in the LED light source 22 .

In this embodiment, a commercially available LED PKG7030 is selected for illustration (other commercially available LED light sources 22 can also achieve the same effect), and the long side direction of the LED PKG7030 is parallel to the installation direction of the lenticular lens. Among them, the light intensity distribution curve of the purchased LED PKG7030 is shown in Figure 8. It can be seen that its light-emitting angle is about 120°, and the light intensity is the strongest at the front view angle, and the light intensity is weaker with a larger viewing angle.

After the LED PKG7030 is used in the backlight module of this embodiment, the light distribution curve is shown in Figure 9. It can be seen that the convex part of the concave-convex lens scatters the light intensity at the position corresponding to the right-angled side of the isosceles right-angled triangle to other angles , which means that the light intensity at this position is relatively weakened, and the overall large viewing angle light intensity is enhanced, so as to achieve the effect of improving the uniformity of light intensity on the light emitting surface. And after simulation analysis, the reflection percentage of light inside the total reflection prism of this embodiment is about 15%, and the percentage of refraction on the two right-angled surfaces of the total reflection prism is about 85%.

Preferably, the plate body 31 includes a light guide plate or a diffusion plate, and the plate body 31 is provided with diffusion particles or a scattering air layer, and the diffusion particles are selected from optical resin PMMA particles, and are dispersed in each of the plate materials as scattering particles or air bubble layers. Between the tree finger layers, light lines will continue to propagate in two media with different refractive indices when passing through the diffusion layer, and many phenomena of refraction, reflection and scattering will occur, thereby producing optical diffusion and enhancing the uniformity of light.

Among them, the diffusing particles can further diverge the light and increase the uniformity of the light output. It should be noted that the light source 22 can be selected from a diffuser plate or a light guide plate. Figure 10 and Figure 11 respectively show the simulation effect of the concave lens image of the diffuser plate and the light guide plate with LED PKG7030 respectively. It can be seen that the structural image performance of the light guide plate is slightly better than that of the diffuser plate. structure, but both design structures can meet the screen requirements. Specifically, according to the specific model of the light source 22, light intensity distribution, pattern design of the scattering dots on the light incident surface of the light guide plate, etc., different concave-convex lenses can be used for light distribution to obtain the best matching structure, so that the light emitted by the LED can enter without loss. In the diffusion plate or the light guide plate, at the same time, the light can be transmitted to the far end without changing the transmission direction of the light, thereby greatly improving the light extraction efficiency.

Preferably, the concave-convex lens is formed by thermal rolling or coating optical resin on the second surface of the plate body 31 .

That is to say, here is a specific method for forming the concave-convex lens. Specifically, hot rolling or coating a layer of optical resin raw material on the light-emitting surface of the diffuser plate is enough to form the concave-convex lens structure. The preparation steps of the method are simple and convenient, and the positions of the concave and convex parts of the obtained meniscus lens are accurate.

Example 4:

This embodiment provides a display device, including the above-mentioned backlight module. The display device may be any product or component with a display function such as a liquid crystal display panel, electronic paper, mobile phone, tablet computer, television, monitor, notebook computer, digital photo frame, navigator, and the like.

Obviously, many changes can be made to the specific implementation of the above-mentioned embodiments; for example, the specific dimensions of the first lens structure and the second lens structure can be selected according to needs, and the distance between light sources, _h1 and h2 can be _adjusted according to needs. Adjustment.

It can be understood that, the above embodiments are only exemplary embodiments adopted for illustrating the principle of the present invention, but the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also regarded as the protection scope of the present invention.

Claims (8)

1. a kind of backlight module characterized by comprising

The plate body of light-permeable, wherein the light-emitting surface of plate body is the second face, and the face opposite with the second face is the first face；

The first lens arrangement in the first face of plate body；

The light source being embedded inside first lens arrangement；

The second lens arrangement on the second face of plate body；

First lens arrangement includes total reflection lens, and second lens arrangement includes combining shape by concavees lens and convex lens At concave-convex lens；

Where perpendicular to the plate body on the direction in face, the section of the total reflection lens is isosceles right triangle, described The bevel edge of isosceles right triangle is parallel to the face where the plate body, and the right angle of the isosceles right triangle is compared to described Bevel edge is arranged closer to the second face of the plate body；The light source is embedded on the bevel edge of the isosceles right triangle.

2. backlight module according to claim 1, which is characterized in that the recess portion of the concave-convex lens corresponds to isosceles right angle three At angular square position, the protrusion of the concave-convex lens is corresponded at the right-angle side position of isosceles right triangle.

3. backlight module according to claim 1, which is characterized in that the height of the isosceles right triangle is h₁, hanging down Directly where the plate body on the direction in face, the plate body is having a size of h₂, h₁: h₂Range be (3-4.5): 5.

4. backlight module according to claim 1, which is characterized in that the light source includes LED light, and the LED light is separate The side in second face is equipped with reflecting layer.

5. backlight module according to claim 4, which is characterized in that first lens arrangement includes that total reflection column is saturating Mirror, the interior interval of every total reflection cylindrical lenses are embedded with multiple LED light.

6. backlight module according to claim 1, which is characterized in that first face of plate body is set far from the side in the second face There is reflector plate.

7. backlight module according to claim 1, which is characterized in that the plate body includes light guide plate or diffuser plate, described Diffusion particle is equipped in plate body.

8. a kind of display device, which is characterized in that including the described in any item backlight modules of claim 1-7.