CN1595255A - Direct type backlight module - Google Patents

Abstract

This invention discloses a straight down aphototropism mode set, which comprises at least one light tube, light cover surrounding the light tube part, diffusing plate and reflection element. The light tube and light cover are located in the defined area of reflection element and diffusing plate and the light cover is located between the light tube and the diffusing plate. The light beam sent from the tube is transmitted into the diffusing plate and is translated into the even plane light after the light cover reaction. This invention of down straight aphototropism mode set has high evenness of the out light.

Description

Direct type backlight module

【Technical field】

The invention relates to a backlight module, in particular to a direct-lit backlight module using a lamp tube.

【Background technique】

Due to the advantages of lightness, thinness, and low power consumption, liquid crystal displays are widely used in modern information equipment such as notebook computers, mobile phones, and personal digital assistants. Because the liquid crystal itself does not have light-emitting properties, it is necessary to provide a backlight module for it to realize the display function. The backlight module can be divided into two types according to the structure: the edge type backlight module and the direct type backlight module. Among them, the direct type backlight module is mainly used in fields such as LCD monitors or LCD TVs.

As we all know, the direct-type backlight module needs to have higher light output brightness, and its light output uniformity must meet the predetermined requirements, so as to improve the color contrast, full-screen area brightness effect and the viewing angle of the whole machine of the liquid crystal display using the backlight module. In addition, in order to meet the light and thin requirements of the liquid crystal display, its structural design should not be too complicated.

The direct-lit backlight module in the prior art generally includes a light source array composed of a plurality of light emitting diodes and a diffuser panel placed on one side of the light output surface of the light source array. However, the direct-type backlight module using light-emitting diodes has the following defects: the price of light-emitting diodes is high, which increases the cost of direct-type backlight modules; the light field distribution of light-emitting diodes is rotationally symmetrical, and the light uniformity is difficult to meet the needs of liquid crystal displays ; and in order to match the scattering panel, it is necessary to adopt the design of multiple light emitting diodes, which makes the light source array bulky, complex in structure and consumes a lot of power, and when a certain light emitting diode breaks down, it will affect the overall light uniformity. The transmission direction of the light beam emitted by the light source, converting the line light source or point light source into a surface light source to emit.

Therefore, the industry has developed a direct-type backlight module using a lamp as a light source. For a prior art direct type backlight module, please refer to US Patent No. 5,479,328 published on December 26, 1995 (see FIG. 1 ). The direct-type backlight module 10 provides illumination for the liquid crystal display panel 20, and includes a spiral tube (Serpentine Tube) 12, a reflective frame 14, a glass substrate 15, a diffusion plate 17 and a brightness enhancement sheet 18 arranged on the glass substrate 15 , the spiral lamp tube 12 is nested in a plurality of channels (not marked) of the reflective frame 14 . The brightness enhancement sheet 18 is opposite to the liquid crystal display panel 20 through the air gap 19 .

However, since the direct type backlight module 10 only uses the diffuser plate 17 to homogenize the emitted light beams, that is, the uniformity of the light output depends on the quality of the diffuser plate 17, and its control is relatively difficult, and the uniformity of the light output is not ideal. Please also refer to FIG. 2. Because the brightness distribution of the light emitted by the lamp tube 12 is inversely proportional to the square of the distance, the light beam emitted by the direct-type backlight module 10 forms uneven brightness and darkness on the surface of the diffuser plate 17 according to the light transmission distance. distributed.

In addition, the prior art direct-type backlight module 10 also has the following defects: in order to improve the light uniformity as much as possible, the design of the reflective frame 14 is extremely difficult, which increases the complexity of the structure of the direct-type backlight module 10; The shape of the lamp tube 12 is complicated, it is relatively difficult to manufacture, and the price and power consumption are relatively high.

【Content of invention】

In order to overcome the defects of low light uniformity and complicated mechanism design of the prior art backlight module, the present invention provides a direct type backlight module with high light uniformity and simple mechanism design.

The technical solution of the present invention to solve the technical problem is to provide a direct-lit backlight module comprising at least one lamp tube, a lampshade partially surrounding the lamp tube, a diffuser plate and a reflective element. The at least one lamp tube and the lampshade are located in the area defined by the reflective element and the diffuser plate, and the lampshade is located between the lamp tube and the diffuser plate, the light emitted by the lamp tube is transmitted to the diffuser plate after being acted on by the lampshade and converted into uniform plane light .

Compared with the prior art that simply uses a diffuser plate to homogenize the emitted light beams, the beneficial effect of the present invention is that since the direct type backlight module of the present invention adopts the lampshade between the lamp tube and the diffuser plate, the light emitted by the lamp tube passes through The light shade is homogenized by transmission and refraction before being transmitted to the diffusion plate, which can effectively improve the light uniformity of the direct-lit backlight module; and compared with the reflective frame with multiple channels in the prior art, the present invention also has a mechanism The advantage of simple design.

【Description of drawings】

FIG. 1 is a cross-sectional view of a direct-lit backlight module in the prior art.

FIG. 2 is a partial light path diagram of the direct type backlight module shown in FIG. 1 .

FIG. 3 is a perspective view of the direct type backlight module of the present invention.

Fig. 4 is a perspective view of the lampshade shown in Fig. 3 .

FIG. 5 is a schematic diagram of the optical path of the direct type backlight module of the present invention.

【Detailed ways】

Referring to FIG. 3 , the direct-lit backlight module 100 of the present invention includes a plurality of lamp tubes 101 , a lampshade 102 partially surrounding the lamp tubes 101 , a diffuser plate 103 and a reflective element 104 . The lamp tube 101 and the lampshade 102 are located in the area defined by the reflective element 104 and the diffuser plate 103, and the lampshade 102 is located between the lamp tube 101 and the diffuser plate 103, and the light emitted by the lamp tube 101 is transmitted to the diffuser plate after being acted on by the lampshade 102 103 and converted into a uniform plane light.

The lamp tube 101 may be a cold-cathode fluorescent lamp, which has the advantages of high brightness, high luminous efficiency, thin tube diameter, and long service life compared with other light source technologies. The tube diameter of the lamp tube 101 is about 10mm, the power is about 8-29w, the service life is as long as 10000hrs, and the luminous flux is about 35-90lm.

The light emitting principle of the lamp tube 101 is similar to that of the fluorescent tube, relying on the energy state conversion of the gas atoms in the lamp tube 101 into radiant light. The most commonly used discharge medium is mercury vapor. The lamp tube 101 will be filled with inert gases such as Ar, Kr, Ne, etc. to assist activation. The free electrons in the lamp tube 101 are accelerated by the electric field to excite Ar atoms, and the excited Ar will make the mercury atoms Dissociation and release of radiant energy mainly produces two kinds of ultraviolet light (UV-Radiation) at 253.7nm and 185nm, of which 235.7nm has the highest radiation efficiency, and emits light after exciting the phosphor on the tube wall. By adjusting the formula of the phosphor, it can Emit light with different color temperatures, such as reddish or bluish to meet the requirements of different displays.

Please refer to FIG. 4 , the lampshade 102 is made of optically transparent material, one of optical grade acrylic polymer, high molecular polymer, high molecular carbide, glass or quartz can be selected. The lampshade 102 is roughly in the shape of an arc column, including a substrate 121 and a plurality of diffusion points 122 arranged thereon. The plurality of diffusion points 122 are microlenses, which are distributed on the surface of the substrate 121 according to the principle that the brightness of light is inversely proportional to the square of the distance. , that is, the diffusion points 122 corresponding to the farther light transmission distances are larger, and the diffusion points 122 corresponding to the longer light transmission distances can also be densely distributed, so that the light rays are evenly distributed after being refracted and transmitted, thereby improving the straight-down The light output uniformity of the type backlight module 100. Of course, the plurality of diffusion points 122 can also be optically transparent particles printed on the surface of the substrate 121 , which can be one of spherical, ellipsoidal or rectangular.

Please refer to FIG. 3 again, the diffuser plate 103 is flat, and its function is to make the light beam emitted by the lamp tube 101 and the light beam transmitted by the lampshade 102 fully diffuse when passing through the interior, so as to make the light uniform. The diffusion plate 103 generally includes a substrate and a diffusion layer formed on the substrate. The substrate is made of a material with high light transmittance, and serves as a carrier for the diffusion layer. The diffusion layer is made of general light-guiding plastics such as PMMA (PolymethylMethacrylate) or PC (Polycarbonate, polycarbonate), and mixed with scattering particles. Of course, the diffusion layer can also be a plurality of protruding scattering points formed on the surface of the substrate by a printing process. The material used for the scattering points is a highly divergent light substance, and its shape can be columnar, spherical or tetrahedral, and can be uniform. Distributed on the surface of the substrate, it causes the incident light beam to scatter and refract, so that the light beam is uniformly emitted from the surface of the diffuser plate 103, thereby obtaining planar light.

The reflective element 104 accommodates the lamp tube 101 and the lampshade 102, and the reflective film is coated on the surface to reflect the light projected on it, preventing the light from escaping from the surface of the reflective element 104, thereby improving the utilization rate of light energy and increasing the direct-down type. The light output brightness of the backlight module 100 .

Please refer to FIG. 5 together. During operation, the lamp tube 101 emits light, part of the light is directly incident on the lampshade 102, and the rest of the light is incident on the lampshade 102 and the diffuser plate 103 after being reflected by the reflective element 104. The lampshade 102 partially surrounds the lamp tube 101. The light projected on it is transmitted to the diffusion plate 103 after being transmitted and refracted by the diffusion point 122, and the diffusion plate 103 scatters the received light so that it is evenly distributed in the light output area to form the required plane light.

Claims (10)

1. down straight aphototropism mode set, comprise at least one fluorescent tube, diffuser plate and reflecting element, it is characterized in that: it further comprises at least one lampshade of part around corresponding fluorescent tube, this fluorescent tube and lampshade are housed in the space that reflecting element and diffuser plate define, and lampshade is between fluorescent tube and diffuser plate, and the light that fluorescent tube sends transfers to diffuser plate and converts uniform in-plane light to after the lampshade effect.

2. down straight aphototropism mode set as claimed in claim 1 is characterized in that: this lampshade adopts the optics light-transmitting materials to make.

3. down straight aphototropism mode set as claimed in claim 2 is characterized in that: the material of this lampshade is acrylic polymers, high molecular polymer, macromolecule carbonization thing, glass or quartz.

4. down straight aphototropism mode set as claimed in claim 1 is characterized in that: this lampshade is the circular arc column.

5. down straight aphototropism mode set as claimed in claim 1 is characterized in that: this lampshade comprises base material and is arranged at a plurality of diffusion points of base material.

6. down straight aphototropism mode set as claimed in claim 5 is characterized in that: these a plurality of diffusion points are lenticules.

7. down straight aphototropism mode set as claimed in claim 5 is characterized in that: the size of these a plurality of diffusion points increases progressively with the light transmission distance.

8. down straight aphototropism mode set as claimed in claim 5 is characterized in that: the density of these a plurality of diffusion points increases progressively with the light transmission distance.

9. down straight aphototropism mode set as claimed in claim 1 is characterized in that: these a plurality of diffusion points are the optical clear particles that are printed on substrate surface.

10. down straight aphototropism mode set as claimed in claim 9 is characterized in that: these a plurality of diffusion points are spherical shape, oval spherical or rectangular-shaped.

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