CN101153700A - Direct type backlight module structure - Google Patents

Abstract

The invention relates to a direct type backlight module structure, which comprises a reflecting cover, a plurality of lamp sources accommodated in the reflecting cover, a substrate arranged above the lamp sources, and microstructures formed on at least one surface of the substrate for emitting light and emitting light, wherein the half visual angle can be converged and the 0-degree visual angle intensity can be improved by the mutual matching of the reflecting cover, the substrate and the microstructures, and the direct type backlight module structure has the advantages of high light transmittance, high luminance, light homogenization and the like.

Description

Direct type backlight module structure

technical field

The invention relates to a diffuser plate with a surface microstructure, in particular to a direct-type backlight module that uses a substrate and a microstructure together with an arc-shaped reflector.

Background technique

Generally, the direct-type backlight module cannot meet the requirement of uniform backlight with uniform luminance without an optical film, and when our eyes look directly at different positions of the backlight module, we will find that the uniformity of the luminance distribution of the backlight module is extremely poor, which can I understand that this is because the light above the lamp tube can directly enter the eyes, and the farther away from the lamp tube, because the light cannot effectively diffuse to the dark zone next to the lamp tube, and the light cannot be effectively concentrated into the retina of the eye, and this kind of The backlight phenomenon with extremely uneven luminance is usually called MURA defect in the display, so the direct-lit backlight module needs to add a diffuser plate (Diffuser Plate) and a diffuser film (Diffuser Film) to improve the uneven light source or lamp. MURA deficiencies.

However, the current diffuser plate used in the direct type backlight module is made of transparent optical polymer material, and diffuser particles are added into the material. Those who pay attention to it further create a hemispherical (or semi-columnar (LENTICULAR)) refraction structure on the light-emitting or light-incoming surface of the diffuser plate. In this way, although the uniform diffusion effect is improved, the hemispherical columnar microstructure The lens generally has lens aberration (Aberration), so the angle of light diffusion is very large, because the angle of light diffusion is too large, and the human eye is limited by the field of view (Field of View) when receiving the luminance (Brightness) of the light source , so that the overall luminance of the liquid crystal display that the human eye finally feels is greatly reduced, which is caused by the fact that most of the light emitted by the backlight cannot really enter the retina of the human eye.

When the number of lamp tubes decreases and the distance between the lamp tubes increases (for example, the LCD TV backlight module originally used 16 cold-cathode lamps at 32 o'clock, but has been reduced to 12), if you continue to use the traditional method and only add diffusion Diffusion plates designed with particles or hemispherical refraction structures have been unable to meet the strict requirements of no MURA defects, and must rely on increasing the thickness of the backlight module to increase the diffusion and reduce MURA defects. Therefore, if we continue to adopt the traditional diffuser plate design in the future, we will encounter the problem of reducing the number of lamp tubes or reducing the thickness of the backlight module. Therefore, the design of the diffuser in the future must have new optical design considerations, that is, it must be able to effectively guide the light from the backlight into the eyes, and must be able to achieve a certain level of brightness and uniformity.

Contents of the invention

Therefore, the main purpose of the present invention is to provide a micro lens made by using the design principle of Fresnel Lens and Snell's Law on at least one surface of the light-emitting and incident-light of the substrate. Structure to converge the half angle of view and increase the strength of the 0 degree angle of view. In addition, the substrate and microstructure can converge the half viewing angle and improve the intensity of the 0-degree viewing angle. However, in order to ensure the uniformity of the backlight module passing through the substrate, a specially designed arc-shaped reflector is required, and the light source is emitted by the reflector. Part of the light reflected to the substrate, the invention can converge the half angle of view within ±10 degrees, and the intensity of the 0 degree angle of view is obviously increased by about 125%.

In order to achieve the above purpose and other purposes, the present invention provides a direct type backlight module structure, including:

Several light sources, with a certain distance between the light source and another light source;

The reflector is in the shape of a continuous parallel arc, and the aforementioned light source is accommodated in the reflector;

The substrate, located above the above-mentioned light source, is made of polymer light-transmitting material; and

The microstructure is formed on at least one surface of the aforementioned substrate on which the light exits and enters the light, and includes several sets of patterns.

By means of the above technical means, the present invention can improve the shortcomings of the prior art and have the advantages of high light transmittance, high luminance and light uniformity.

Description of drawings

Fig. 1 is a side view of the internal structure of the first embodiment of the direct type backlight module structure of the present invention;

2 is a partial enlarged view of the substrate of the first embodiment of the present invention and the microstructure formed on the surface of the substrate;

3 is a side view of the internal structure of the second embodiment of the direct type backlight module of the present invention;

4 is a partial enlarged view of the substrate of the second embodiment of the present invention and the microstructure formed on the surface of the substrate; and

FIG. 5 is a graph of the horizontal viewing angle intensity of the direct-lit backlight module of the present invention and the direct-lit backlight module of the prior art.

Explanation of reference numerals: 1-light source; 2-reflector; 3-substrate; 31-ultraviolet absorber; 32-diffusion particles; 4-microstructure; 41-pattern; -pattern; 511-meander; 6-microstructure; 61-pattern; 611-meander; R-radius; PL-pitch; P-width; P1-width; P2-width; θ-angle; θ1-angle; θ2-angle; H-corresponding depth; H1-corresponding depth; H2-corresponding depth; Z1-first distance; Z2-second distance; A-A curve; B-B curve.

Concrete way

With regard to the techniques, means and effects achieved by the present invention, the preferred embodiments are listed below and described in detail in conjunction with the accompanying drawings, so that a deep and specific understanding can be obtained therefrom.

Please refer to FIG. 1 and FIG. 2, the structure of the direct-lit backlight module according to the first embodiment of the present invention includes:

A plurality of light sources 1, the light source 1 can be a cold cathode fluorescent lamp (CCFL) or one of LED light emitting diodes, and there is a certain distance PL between the light source 1 and another light source 1 .

The reflector 2 is arc-shaped continuously side by side, and its radius R is defined as 0.5 to 0.75 times of the aforementioned distance PL; and the aforementioned light source 1 is accommodated in the reflector 2, and the material of the reflector 2 is selected from poly armor Poly(Methyl methacrylate), PMMA), polycarbonate (Polycarbonate, PC), methyl methacrylate polystyrene ((Methyl methacrylate) Styrene, MS), polystyrene (PolyStyrene, PS), at least one of aluminum (Al), silver (Ag), nickel (Ni), copper (Cu) and tin (Su); the reflector 2 is used to reflect part of the light emitted by the aforementioned light source 1, and to borrow The light can be more concentrated by the reflector 2 .

The substrate 3 is arranged above the light source 1 and is made of a polymer light-transmitting material selected from polymethyl methacrylate (PMMA), polycarbonate (Polycarbonate) , PC), methyl methacrylate polystyrene ((Methyl methacrylate) Styrene, MS) and polystyrene (PolyStyrene, PS) at least one material; another substrate 3 is doped with an ultraviolet absorber 31 inside, to Block the direct irradiation of ultraviolet rays, and avoid the phenomenon of yellowing and cracking of the diffusion plate. Professionals in the technical field can easily understand); and the inside is doped with some diffusion particles 32, the diffusion particles 32 are selected from polycarbonate resin (Polycarbonate, PC), polymethyl methacrylate (Poly (Methyl methacrylate), PMMA ), methyl methacrylate polystyrene ((Methylmethacrylate) Styrene, MS), polystyrene (PolyStyrene, PS), silicon oxide (Silica), silicon (Silicon), melamine (Melamin), calcium carbonate, Teflon , titanium dioxide (TiO2) and silicon dioxide (SiO2) (silicon oxide (Silica) in the front and silicon dioxide at the back are actually the same thing, all are silicon dioxide. So I have used "silicon oxide" in the following claims At least one material in ) is deleted, so that when the light emitted by the lamp source 1 passes through the diffusing particles 32, an optical diffusion effect is caused (the doping amount of the diffusing particles should have an approximate ratio). (the volume ratio of the diffusion particles 32 and the substrate 3 is about 15% to 85%, but the ratio of the doping amount of the diffusion particles is not the key point of this case) and

The microstructure 4 is formed on at least one surface of the aforementioned substrate 3 where the light exits and enters the light, and includes several groups of very fine patterns 41, the patterns 41 have several different widths P, different angles θ, and different corresponding depths The curved portion 411 of H, the width P of the curved portion 411 is between 0.05mm and 0.5mm, and the angle θ of the curved portion 411 is different, the principle of the design of the angle θ of the curved portion 411 is the same as that of the Fresnel lens ( Fresnel Lens) design principles are the same, and the parameters needed to design the bending portion 411 depend on the number N of the above-mentioned light sources 1, the distance PL between the light source 1 and another light source 1, and the first distance between the light source 1 and the substrate 3 Z1, and the second distance Z2 between the light source 1 and the reflector 2, with the interval PL as a period, the value of the first distance Z1 plus the second distance Z2 is the back focal length of the lens, and the front focal length is set to infinity , and using Snell's Law (Snell's Law), the change value of the angle θ of each bending part 411 can be determined. In other words, if the backlight module uses a total of N light sources 1, then the microstructure 4 has a total of N groups of periodic pattern 41, and the rate of change of the angle θ of the meander portion 411 in each period is the same. Referring to FIG. 2 , the angle θ of the meander 411 changes from 0° to 70° starting from directly above the light source 1 as the center value, and the corresponding depth H of the meander 411 varies from 0 to twice the width P of the meander 411 .

Please refer to FIG. 5 , which is a graph illustrating the structure of the direct type backlight module designed in the prior art (curve A) and the first embodiment of the present invention (curve B). The direct-type backlight module of the prior art and the direct-type backlight module structure of the first embodiment of the present invention are used to measure the final luminance and uniformity of the module with a luminance measuring instrument (for example: model Topcon BM7-fast), which proves the present invention The half viewing angle can be converged within ±10 degrees, and the strength of the 0-degree viewing angle can be significantly increased by about 125%.

Please refer to FIG. 3 and FIG. 4, the structure of the direct type backlight module of the second embodiment of the present invention is basically the same as that of the first embodiment, the difference is that the microstructures 5 and 6 of the second embodiment are formed on the substrate 3, the microstructures 4 formed on one side of the substrate 3 are changed to the microstructures 5 and 6 formed on both sides of the substrate 3 on the light-emitting and light-incident surfaces; wherein, the widths P1 and P2 of the bending parts 511 and 611 are between 0.05 Between mm and 0.5mm, the width P1 can be the same as or not equal to the width P2, in order to avoid interference fringes as a principle, and the angles θ1 and θ2 of the bending parts 511, 611 vary from 0° to 40°, and the bending parts The corresponding depths H1 and H2 of 511 and 611 vary from 0 to 0.5 times the width P1 and from 0 to 0.5 times the width P2.

By means of the above-mentioned technical means, the second embodiment of the present invention has several advantages: (1) First, the design of the double-sided microstructure 5 and 6 in the second embodiment is used to control the directionality of light, which is better than that in the first embodiment. The space for the single-sided microstructure 4 to control the direction of light is large. (2) Second, in terms of technology, the double-sided microstructures 5 and 6 of the second embodiment can share the excessive angle caused by the single-sided microstructure 4 of the first embodiment (cause the depth is too deep, which will affect the release property ), so the designed structure depth of the double-sided microstructures 5 and 6 in the second embodiment can be reduced by about half, while still maintaining the same optical properties.

In addition, in the first embodiment and the second embodiment, the substrate 3 and the microstructures 4, 5, 6 formed on the light-emitting and light-incident surfaces of the substrate 3 can be extruded or co-extruded. Type (Co-Extrusion) and injection process, the plate thickness is 0.08 to 3.0mm, the extruded plate can be a single layer (extrusion) or a sandwich structure (co-extrusion), if it is a sandwich structure, it can be divided into a core layer And the subsidiary (Sub) layer, the total thickness of the diffusion plate is 0.08-3.0mm, and the thickness of the subsidiary layer is 50-200μm.

Claims (12)

1. a directly-down backlight module structure is characterized in that, includes:

Several lamp sources have certain spacing between lamp source and another lamp source;

Reflector is continuous circular arc side by side, and aforesaid lamp source is placed in the reflector;

Substrate is located at above-mentioned top, lamp source, makes with the macromolecule light-transmitting materials, and

Micro-structural is formed at least one surface of the bright dipping of aforesaid base plate and light inlet, comprises some groups pattern.

2. directly-down backlight module structure as claimed in claim 1 is characterized in that, this lamp source can be cathode fluorescent tube (CCFL) or for the LED light emitting diode one of them.

3. directly-down backlight module structure as claimed in claim 1 is characterized in that, the radius of the circular arc of reflector is 0.5 to 0.75 times of distance between lamp source and another lamp source.

4. directly-down backlight module structure as claimed in claim 1, it is characterized in that the reflector material is selected from least a material in polymethyl methacrylate, Merlon, methyl methacrylate polystyrene, polystyrene, aluminium (Al), silver (Ag), nickel (Ni), copper (Cu) and the tin (Su).

5. directly-down backlight module structure as claimed in claim 1 is characterized in that, the macromolecule light-transmitting materials of substrate is selected from least a material in polymethyl methacrylate, Merlon, methyl methacrylate polystyrene and the polystyrene.

6. directly-down backlight module structure as claimed in claim 1 is characterized in that substrate inside is doped with ultra-violet absorber.

7. directly-down backlight module structure as claimed in claim 1 is characterized in that substrate inside is doped with some diffusion particles.

8. directly-down backlight module structure as claimed in claim 7, it is characterized in that diffusion particle is selected from least a material in Merlon, polymethyl methacrylate, methyl methacrylate polystyrene, polystyrene, silicon, melamine, calcium carbonate, Teflon, titanium dioxide and the silica.

9. directly-down backlight module structure as claimed in claim 1 is characterized in that, pattern has several zigzag parts of different in width, different angles, the different corresponding degree of depth.

10. directly-down backlight module structure as claimed in claim 9 is characterized in that width circle of zigzag part is in 0.05mm to 0.5mm.

11. directly-down backlight module structure as claimed in claim 9 is characterized in that, the variation from 0 ° to 70 ° of zigzag part angle.

12. directly-down backlight module structure as claimed in claim 9 is characterized in that, the corresponding depth H of zigzag part is in 0 to 1 times of range of zigzag part width.

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