CN1580830A - Method for defining patterns on a light guide plate - Google Patents

Abstract

A method for defining patterns on a light guide plate installed in a liquid crystal display device. The method comprises the following steps: providing a metal plate with a plurality of holes, attaching the metal plate on the light guide plate, providing a nozzle for spraying ink, then placing the nozzle above the metal plate, and spraying the ink from the nozzle, so that the ink passes through the holes and forms a pattern on the light guide plate, and the pattern is used for diffusing the light entering the light guide plate.

Description

Method for defining patterns on a light guide plate

technical field

The invention relates to a method for defining a pattern on a light guide plate, in particular to a method for processing a light guide plate pattern with a simple manufacturing process and a high pattern completion rate.

Background technique

The backlight module is one of the important devices of liquid crystal display products, and has been widely used in related products such as digital cameras, mobile phones, digital personal assistants (PDAs), computer monitors, and flat-screen TVs. Generally speaking, the backlight module is mostly arranged on the back of the display panel, including a light source generator, a light guide plate, a reflection sheet, a diffusion sheet, and several optical films or prism sheets. The light guide plate is used to diffuse the light source generated by the light source to the display panel, the diffuser plate is used to uniformly disperse the light source, and the optical film or prism sheet is placed above the diffuser plate to improve the brightness and uniformity of the backlight module.

Backlight modules can be roughly divided into two designs: "direct-underlying" and "edge light". The design of the direct type backlight module is to place the light source generator on the back of the display panel. Due to the large installation space, multiple lamp tubes can be used to increase the light intensity. Therefore, a display panel with higher brightness and larger size is generally required, such as a high-brightness or outdoor LCD monitor or LCD TV, that is, it is suitable to use a direct-lit backlight module as a display light source.

Please refer to FIG. 1 . FIG. 1 is a schematic cross-sectional view of a conventional direct-type backlight module 10 . As shown in FIG. 1 , the direct type backlight module 10 is disposed under a liquid crystal display panel 12 . The direct type backlight module 10 includes at least one light source 14, a light guide plate 16 is arranged above the light source 14, a diffusion sheet 18 is arranged between the light guide plate 16 and the liquid crystal display panel 12, and a prism sheet 20 is arranged above the diffusion sheet 18, And a reflective sheet (reflecting sheet) 22 is disposed under the light source 14, and the direct type backlight module 10 also includes a housing (housing) 24. The light guide plate 16 is used to evenly spread the light generated by the light source 14 . Generally speaking, the light guide plate used in the direct type backlight module is flat, and its shape is shown as the light guide plate 16 in FIG. 1 .

Please refer to FIG. 2 , which is a schematic cross-sectional view of a conventional side-lit backlight module 50 . The edge-lit backlight module places the light source on the side to reduce the thickness of the backlight module. This design considers user needs such as lightness, thinness, and power saving. Therefore, at this stage, LCD panels for notebook computers are mainly used. The backlight module 50 includes a wedge-shaped light guide plate 52, a light source 54 composed of a cold cathode fluorescent lamp (CCFL) arranged on the side of the light guide plate 52, a diffuser 56 arranged above the light guide plate 52, a first prism The sheet 58 and a second prism sheet 60 are sequentially disposed on the diffusion sheet 56 , and a reflective sheet 62 is disposed on the bottom surface of the light guide plate 52 . As shown in FIG. 2, the existing edge-lit backlight module 50 uses a wedge-shaped light guide plate 52, and a light source 54 is arranged on the end surface of the thick side of the light guide plate 52, so that the light generated by the cold cathode tube enters the light guide plate in the form of end surface illumination. light board 52 . The light entering the light guide plate 52 is guided to the thin end of the light guide plate 52 due to total reflection. A special pattern is formed on the bottom surface of the light guide plate. When light hits the bottom surface of the light guide plate 52, the angle of reflection will be adjusted due to the pattern on the bottom surface of the light guide plate 52, so that the light guide plate 52 can evenly guide the light to the display panel.

From the above, it can be seen that the light guide plate is one of the key components of the backlight module, and its function is to guide the scattering direction of light. A pattern is provided on the bottom surface of the light guide plate to guide the light evenly, so as to improve the luminance of the display panel and ensure the uniformity of the luminance of the display panel. There are two ways to make the pattern of the existing light guide plate according to the production process. The first way is to use screen printing (screen printing) to use "high reflectivity" and "non-reflective" on the acrylic (acrylic) flat plate. Light-absorbing" material, print a circular or square pattern on the bottom of the light guide plate. The second method is to use a mold to directly form a light guide plate with a pattern by injection molding. Please refer to FIG. 3 for the method. FIG. 3 is a schematic diagram of injection molding of a conventional light guide plate. Firstly, the sheet metal 70 with a light guide plate pattern is flatly attached to the female mold (or mirror surface mold core) 72 of the injection molding mold, and then the molds are closed so that the male mold 74 and the female mold 72 are closely combined. At this time, the raw material (usually propylene, commonly known as acrylic) is injected into the mold cavity 76 from the injection port of the male mold 74 along the direction of the arrow, and the pattern of the light guide plate is transferred with the duplication machine such as an injection molding machine and a heat press machine. On the acrylic board, complete the production of the light guide plate.

However, in the existing light guide plate manufacturing technology, there are disadvantages such as high manufacturing cost (such as screen loss) and large pattern error, which makes it impossible for light guide plate manufacturers to reduce the production cost and improve the pattern accuracy. Therefore, if a light guide plate pattern processing method with simple manufacturing process, precise pattern transfer, and low manufacturing cost and loss rate can be developed, it will help to improve the product qualification rate.

Contents of the invention

The main purpose of the present invention is to provide a method with a simple manufacturing process and can accurately complete the pattern of the light guide plate, so as to solve the above-mentioned problems.

The invention provides a method for defining patterns on a light guide plate, wherein the light guide plate is installed in a liquid crystal display device. The method includes the following steps. First, a metal filter plate is provided, and the metal filter plate has a plurality of holes, and then the metal filter plate is attached to the light guide plate. Next, a spray nozzle for spraying an ink is provided, and the spray nozzle is placed above the metal plate. Finally, the ink is sprayed from the spray head so that the ink passes through the plurality of holes to form a pattern on the light guide plate, and the pattern is used to diffuse the light entering the light guide plate.

The method of the present invention is mainly to process the preliminarily completed light guide plate, and use the way of spraying ink to make the ink pass through the metal sheet with the pattern hole of the light guide plate and adhere to the light guide plate, thus completing the production of the surface pattern of the light guide plate. According to the method of the present invention, the backlight module manufacturer can adjust the amount of ink ejected according to the requirements of the light guide plate to form patterns of the light guide plate with different thicknesses, so only a single metal sheet can be used to produce light guide plates with different requirements.

In addition, the mold used to transfer the pattern of the light guide plate in the method of the present invention forms a plurality of holes with the pattern of the light guide plate on the thin metal plate by etching and penetrating technology, so that errors caused by mechanical processing can be avoided, and precise and complete reservation can be made. The pattern of the light guide plate with a microstructure improves the efficiency of the light guide plate in guiding light diffusion and evenly distributing the light. Furthermore, the manufacturing process and the follow-up tool cleaning method of the method of the present invention are simpler and time-saving than the existing methods, and the tool consumption rate is low, so the manufacturing cost can be greatly reduced in the overall light guide plate manufacturing process, and the improvement can be effectively improved. At present, light guide plate manufacturers are facing problems such as troublesome manufacturing process, difficult cleaning and high mold cost.

Description of drawings

FIG. 1 is a schematic cross-sectional view of an existing direct-type backlight module structure;

2 is a schematic cross-sectional view of the existing side-lit backlight module structure;

FIG. 3 is a schematic diagram of an existing injection molding method of a wedge-shaped light guide plate;

4 is a schematic diagram of a method for forming a light guide plate pattern according to the present invention;

FIG. 5 is a flowchart of a method for forming a pattern of a light guide plate according to the present invention.

Detailed ways

Please refer to FIG. 4 , which is a schematic diagram of a method for forming a pattern of a light guide plate according to the present invention. In the method of the present invention, a thin metal plate 102 is used as a mold for transferring the pattern of the light guide plate, and a predetermined pattern of the light guide plate is formed on the thin metal plate 102 by etching and penetrating technology. In this step, firstly a photoresist layer is formed on the thin metal plate 102, and then a photolithography process is performed on the photoresist layer using a photomask having a predetermined light guide plate pattern. Next, remove the part of the photoresist layer with the light guide plate pattern, and then use an etchant to remove the part of the thin metal plate 102 that is not covered by the photoresist layer, so that a plurality of holes 104 are formed on the thin metal plate 102, and finally The photoresist layer is removed to complete the pattern transfer to the mold metal thin plate 102. This process is called photolithography and etching process. The manufacturing process of yellow light and etching is prior art, so details of the manufacturing process and related materials used are not repeated here. In a preferred embodiment of the present invention, the material used for the thin metal plate 102 may be beryllium (Be) metal or nickel (Ni) metal.

When forming the pattern of the light guide plate 106 , the light guide plate 106 is first fixed on a machine (not shown in the figure), and then the thin metal plate 102 is closely attached to the light guide plate 106 . Next, a spray head 108 is used to move left and right or back and forth in the direction of the arrow shown in FIG. 4 to spray fine ink 110 on the thin metal plate 102 . The ink 110 will pass through the holes on the metal sheet 102, and form the predetermined light guide plate pattern on the light guide plate 106, and finally through subsequent manufacturing processes such as cooling and fixing, the ink is fixed on the light guide plate 106, and the pattern of the light guide plate is completed. processing. The method of the present invention uses the ink with optical scattering properties, so the pattern of the light guide plate formed by the ink can make the light diffuse to various angles, and achieve the function of the light guide plate to guide the direction of light scattering. Regardless of the light-emitting surface or the light-receiving surface of the light guide plate, the method of the present invention can be used to complete the fabrication of the surface pattern of the light guide plate, so as to increase the light-guiding property of the light guide plate. In the present invention, the amount of sprayed ink can be controlled according to the design requirements of the light guide plate 106 to produce different pattern thicknesses. It is also possible to design the density, size Different patterns, combined with the control of inkjet volume, enable the light guide plate to play the highest role in the backlight module.

Please refer to FIG. 5 . FIG. 5 is a flowchart of a method for forming a light guide plate pattern according to the present invention. Based on the above, the inventive method comprises the following steps:

Step 210: providing a thin metal plate, preferably made of beryllium or nickel metal;

Step 220: Forming a predetermined pattern of a light guide plate on the thin metal plate by etching through technology, so that the thin metal plate has a plurality of holes;

Step 230: fixing a light guide plate on a machine table, and then attaching the thin metal plate to the light guide plate tightly;

Step 240: Use a nozzle to move left and right or back and forth to spray fine ink on the metal sheet;

Step 250: The ink ejected from the nozzle will pass through the plurality of holes to form a predetermined pattern on the light guide plate. At this time, the ink output of the nozzle can be controlled to determine the thickness of the pattern;

Step 260: Complete the pattern making on the light guide plate.

Compared with the existing screen printing production methods, the metal sheet used in the method of the present invention has the advantages of easy cleaning and low wear rate compared with the existing screen printing, and the present invention uses ink spraying to form patterns, which is lower than the pattern formed by screen printing. It is more accurate and has lower error. On the other hand, the manufacturing process of the method of the present invention is shorter than the processing time required by the existing injection molding transfer method, the cost of the mold is also lower, and the degree of completion of the pattern is greatly improved. The method of the invention can be applied to complete the production of the pattern of the light guide plate, which greatly improves the qualified rate of the light guide plate products, reduces the production cost, and improves the market competitiveness of the light guide plate manufacturers.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the claims of the present invention should fall within the scope of the patent of the present invention.

Claims (7)

1. A method for defining a pattern on a light guide plate installed in a liquid crystal display device, the method comprising the following steps: (a) providing a metal plate having a plurality of holes; (b) attaching the metal plate to the light guide plate; (c) providing a spray head for spraying an ink; and (d) placing the nozzle above the metal plate and spraying the ink from the nozzle, the ink passes through the holes to form a pattern on the light guide plate, and the pattern is used to diffuse into the The light from the light guide plate. 2. The method of claim 1, wherein the pattern has a thickness controlled by the amount of ink passing through the plurality of holes. 3. The method of claim 1, wherein the holes are formed on the metal plate by etching. 4. The method as claimed in claim 1, wherein the metal plate is flat and closely attached to the light guide plate. 5. The method of claim 1, wherein the metal sheet is beryllium (Be) metal or nickel (Ni) metal. 6. The method according to claim 1, wherein step (b) is to attach the metal plate to the light incident surface of the light guide plate. 7. The method according to claim 1, wherein step (b) is to attach the metal plate to the light emitting surface of the light guide plate.

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