KR100819542B1 - Light guide plate having a prism and hologram pattern and method for manufacturing thereof - Google Patents

Abstract

The present invention is a light guide plate of a flat panel display backlight, the upper surface is a lenslet irregularities of the shape of a square pyramid for uniformly increasing the amount of light outgoing to the outside and the square size of the bottom of the square pyramid made of 0.5㎛ to 50㎛ The periodic pattern is formed with an isosceles triangle inner angle (A) of 50 ° to 60 ° of the pyramid, and the bottom surface passes through the point light source at one side and scatters and diffuses into a uniform plane light source at one end of the point light source. It relates to a prism and a hologram pattern-integrated light guide plate, characterized in that the width of the non-periodic pattern with a wavefront having a certain size of the square wave projection shape is formed is 0.1㎛ to 20㎛. Thus, when manufacturing the light guide plate greatly improves the light brightness transmitted from the side of the light guide plate, the light source of the upper surface of the light guide plate is also uniformly upward and emits a straight line has the effect of uniform high brightness.

Light guide plate, prism, hologram

Description

Light guide plate having a prism and hologram pattern and method for manufacturing description

1 is an exploded side cross-sectional view of a conventional backlight unit structure.

2 is a bottom view of the structure of a conventional light guide plate.

3 is a view showing an integrated light guide plate having a prism and a hologram pattern of the present invention.

4A and 4B illustrate top and bottom surfaces of an integrated light guide plate having a prism and a hologram pattern according to the present invention.

5A to 5G are diagrams illustrating a process of manufacturing a prism pattern mold part of an integrated light guide plate having a prism and a hologram pattern according to the present invention.

6A to 6G are diagrams illustrating a manufacturing process of a hologram pattern mold part of an integrated light guide plate having a prism and a hologram pattern according to the present invention.

7 is a view showing the application to the injection device of the integrated light guide plate having a prism and hologram pattern of the present invention.

<Explanation of symbols for main parts of drawing>

10: square pattern 11: square pyramid irregularities

30: Spherical wave 32: Hologram wavefront

51,54,71,74 photoresist layer 52,56 silicon substrate

53 mask pattern 57,75 metal layer

58: prism pattern mold portion 72: glass substrate

76: hologram pattern mold portion 91: light source

93: Light guide plate

The present invention relates to a light guide plate of a flat panel display backlight, and more particularly, an upper surface of the flat panel has a high luminance by uniformly increasing the amount of light emitted to the outside. A pattern integrated light guide plate and a method of manufacturing the same.

Liquid Crystal Display (LCD) and Display Panel (Display Panel) essentially include a Back Light Unit (BLU). Cold Cathode Fluorescent Lamp (CCFL) has been mainly adopted as a light emitter on the back and the unit, but it is eco-friendly because it does not contain mercury and can be operated at low voltage, which is suitable for low power consumption and color gamut. Attempts have recently been made to replace Light Emitting Devices (LEDs), which are better at LEDs, for cold cathode fluorescent lamps.

1 is a view showing a backlight device for an LCD (LCD) to which a conventional light guide plate is applied, and FIG. 2 is a view showing a conventional prism sheet and a light guide plate.

As shown in FIG. 1, as a backlight device of a general LCD in which a light guide plate is coupled, the light guide plate in the LCD brightens the liquid crystal environment of the upper part by emitting light incident from a fluorescent lamp attached to the side evenly through the surface. The main acts as a backlight. The backlight is generally a light guide plate 2 and a reflecting sheet 1 below the light guide plate 2 and a diffusion sheet 5, prism sheets 6 and 7 and a protective sheet 8 above the light guide plate 2. And a lamp reflector 4 for fixing the light source 3 and the light source 3 to one side of the light guide plate to reflect light. That is, it is a part that serves to convert the point light source or line light source by the side or rear lamp into the surface light source form. The material of the light guide plate 2 is made of transparent optical resin or PC (polycarbonate), especially PMMA resin called acryl, which is mainly manufactured by injection molding, and is mainly manufactured by injection molding. To emit light, various patterns are attached or engraved on the surface for scattering and reflection of light.

In the conventional light guide plate, light rays scattered by a pattern do not have a constant direction and are diffusely reflected at various angles and emitted to the outside as shown in FIG. 2. In the conventional backlight device, the diffusion sheet 5 is mounted on the light guide plate to evenly spread the light scattered from the pattern portion, and to collect light scattered at various angles in the front direction perpendicular to the surface. By mounting the prism sheets 6 and 7 and the protective sheet 8 on the light guide plate, the surface luminance seen from the front is improved.

However, due to the high price of prism sheets, it has been a major factor to increase the cost of the backlight device for LCD, and efforts have been made to act as a prism sheet by forming fine prism irregularities directly on the upper surface of the light guide plate. In order to manufacture such a mold core for a prism light guide plate, a prism irregularity having a depth of 50 μm or less is engraved over the entire surface of the core, and the fabricated surface is mirrored.

In general, steel lumps are frequently used as a material for injection mold cores. In the conventional manufacturing process, the process of casting, forging and rolling while cooling iron in an application state is performed. The uniformity of crystallization of metallographic structures is reduced due to bubble generation and anisotropic arrangement of crystals. Therefore, when the micro-depth cutting process of 5 to 50 μm is performed on such a material, it is difficult to obtain a mirror surface level of 10 nm or less of the average surface roughness (Ra) required for prism irregularities, and it is difficult to perform the lapping process even after cutting. Therefore, there is a problem that it is difficult to manufacture a mold core having a mirror surface fine prism irregularities with existing materials and processes.

In addition, a method of rotating the abrasive stone at high speed is generally used for mirror surface machining of minute uneven portions, but it is difficult to maintain the precision of the polished stone so as to sharply sharpen the corners of the vertices.

For this reason, despite the many advantages and efforts expected of the separate integrated prism LGP, mass production on a commercial scale has not been achieved until now due to difficulty in manufacturing a mold.

An object of the present invention devised to solve the above problems is to provide a high-brightness light guide plate having a prism and hologram-integrated pattern that varies the depth of etching according to light exposure by exposing than a method of directly grinding and cutting a conventional mold core. In providing.

The prism and hologram pattern integrated light guide plate of the present invention for achieving the above object,

An upper surface of the light guide plate formed of a periodic pattern having an isosceles triangle inner angle A of the quadrangular pyramid from 50 ° to 60 ° and a square pattern length of the bottom of the square pyramid being 0.5 μm to 50 μm;

And a light guide plate lower surface formed of an aperiodic pattern having a width of 0.1 m to 20 m in width at regular intervals at one end of the other end of the light source.

In addition, the prism and hologram pattern integrated light guide plate manufacturing method of the present invention for achieving the above object,

Forming a photoresist layer pattern on a silicon substrate, etching the patterned photoresist layer and the silicon substrate to form square pyramid irregularities on the silicon substrate, and forming a metal layer on the silicon substrate on which the square pyramid irregularities are formed. Prismatic pattern mold portion comprising a; forming, separating the metal layer, and mirror-processing one side surface and the other end surface pattern of the separated metal layer;

Exposing the photoresist layer formed on the glass substrate with refractive interference light, forming a hologram pattern photoresist layer, forming a metal layer on the photoresist layer of the hologram pattern by an electroplating method, and A hologram pattern mold part comprising: separating a metal layer; and mirror-mirroring one side surface and the other end surface of the separated metal layer;

Between the prism pattern mold portion and the hologram pattern mold portion is charged and pressurized by any one material of polymethyl metaacrylate (PMMA), PC (polycarbonate) or resin resin.

Before forming the metal layer, the method further comprises applying a release agent mixed with potassium dichromate (K ₂ Cr ₂ O ₇ Potassium Dichromate, 6g) and ultrapure water (DI WATER, 2000ml).

The isosceles triangle inner angle A of the quadrangular pyramid is preferably formed at 50 to 60 °, more preferably at 57.4 °.

The metal layer is formed by alloying any one or two or more of silver nickel, copper, tin, and chromium, and more preferably, nickel.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view illustrating an integrated light guide plate having a prism and a hologram pattern of the present invention, and FIGS. 4A and 4B illustrate upper and lower surface patterns of the light guide plate of FIG. 3.

As shown in Figure 3, the upper surface of the light guide plate 93 of the present invention is a lenslet irregularities in the shape of a square pyramid to uniform the amount of light outgoing to the outside, the square pattern length of the bottom of the square pyramid is As shown in 4a, it has a periodic pattern which consists of 0.5 micrometer-50 micrometers, and the isosceles triangle internal angle A of the said square pyramid is 50 degrees-60 degrees. At this time, the inner angle A of the isosceles triangle of the pyramid is preferably formed at 57.4 ° for optimal brightness.

As shown in FIG. 4B, the lower surface of the light guide plate 93 has a constant shape of a square wave protrusion at one center of the other end of the point light source 91 so as to pass through the point light source 91 and scatter and diffuse into a uniform surface light source. An aperiodic pattern that is widened at intervals is formed to have a width of 0.1 μm to 20 μm, thereby greatly improving the light luminance transmitted from the side of the light guide plate 93. At this time, a spherical wave 31 and a hologram wavefront 32 are formed to widen to a predetermined size at the other end side central point of the point light source 91.

5 is a manufacturing process diagram of a prism pattern mold part of an integrated light guide plate having a prism and a hologram pattern according to the present invention.

First, as shown in FIG. 5A, a photoresist layer 51 is formed on the silicon substrate 52.

Subsequently, as shown in FIG. 5B, the photoresist layer 51 is exposed using the diffraction grating mask pattern 53, and then, as shown in FIG. 5C, the patterned photoresist layer 54 is formed. .

Subsequently, as shown in FIG. 5D, the photoresist layer 54 and the silicon substrate 52 patterned in the potassium hydroxide (KOH) solution are etched to form a silicon substrate 56 having a square pyramid irregularities. At this time, the length of the square pattern of the bottom of the square pyramid is preferably formed to 0.5 ~ 50㎛, the inner angle (A) of the quadrangular pyramidal isosceles triangle is preferably formed to 50 ° to 60 °, more preferably for optimal brightness Form 57.4 °.

Subsequently, a release agent obtained by mixing potassium dichromate (K ₂ Cr ₂ O ₇ Potassium Dichromate (6 g)) and ultrapure water (DI WATER, 2000 ml) was applied to the pattern of the silicon substrate.

Subsequently, as shown in FIG. 5E, a metal layer 57 having a thickness of 0.3 mm to 1 cm is formed on the upper surface of the silicon substrate 56 having the rectangular pyramidal irregularities shape by electroplating. At this time, when electroplating the silicon substrate 56 of the square pyramid irregularities shape by attaching a mold (not shown) of a predetermined size to prevent damage of the silicon substrate 56 due to the internal tension by the thickness of the plating layer to distribute the internal tension To make. Here, the metal layer 57 is formed by alloying any one or two or more of nickel, copper, tin, and chromium, and more preferably made of nickel.

Subsequently, as shown in FIG. 5F, the metal layer 57 is separated from the silicon substrate 56 having the rectangular pyramidal irregularities. At this time, the release agent is spray-coated to the square pyramid irregularities silicon substrate 56, so that the metal layer 57 is easily separated.

Finally, as shown in FIG. 5G, one side surface and the other end surface of the metal layer 57 may be cut or specularly applied to the injection apparatus to form the prism pattern mold part 58. In this case, the metal layer 57 is mirror-machined for the average surface roughness Ra of 10 nm or less required for cutting the prism to perform cutting and surface processing according to the LCD backlight unit model to form the prism pattern mold part 58. .

6 is a manufacturing process diagram of a hologram pattern mold part of an integrated light guide plate having a prism and a hologram pattern according to the present invention.

First, as shown in FIG. 6A, a photoresist layer 71 is formed on the upper surface of the glass substrate 72, and then exposed to a refractive interference light source as shown in FIG. 6B. In this case, as shown in FIG. 4B, as shown in FIG. 6C, the hologram pattern photoresist layer 74 is formed by the difference in the replication light of the hologram wavefront 32 of the spherical wave 31, and the refractive angle of the light is different. When the refractive interference light is exposed, a pattern is formed according to the amount of contact.

Subsequently, as illustrated in FIG. 6D, the exposed photoresist layer 71 is etched to form a hologram pattern photoresist layer 74.

Subsequently, a release agent mixed with potassium dichromate (K ₂ Cr ₂ O ₇ Potassium Dichromate (6 g)) and ultrapure water (DI WATER, 2000 ml) is sprayed and applied to the pattern of the silicon substrate.

Subsequently, as shown in FIG. 6E, a metal layer 75 having a thickness of 0.3 mm to 1 cm is formed by an electroplating method. Here, the metal layer 75 is formed by alloying any one or two or more of nickel, copper, tin, and chromium, and more preferably, nickel.

Next, as shown in FIG. 6F, the bootie metal layer 75 is separated into the photoresist layer 74 of the hologram pattern. At this time, the release agent is spray-coated to the pattern of the photoresist layer 74 of the hologram pattern and is easily separated.

Finally, as shown in FIG. 6G, one side surface and the other surface of the pattern layer 75 may be cut or specularly applied to the injection apparatus to form the hologram pattern mold part 76.

7 is a view showing the application to the injection device of the integral doping plate having a prism and a hologram pattern of the present invention.

As shown in FIG. 7, the prism pattern mold part 58 and the hologram pattern mold part 76 are mounted inside the injection apparatus including the cylinders 81 and 83 and the supports 82, 84, and 85, and face the pattern. Put the poly methyl meta acrylate (PMMA), PC (polycarbonate) or resin resin in between to move the cylinder (81,83) up and down, and at the same time the prism pattern mold unit 58 is lowered and the hologram The pattern die 76 is raised and pressurized to form the light guide plate.

According to the present invention, a mold may be manufactured by electroplating a prism pattern and a hologram pattern on both sides of a light guide plate for supplying a uniform surface light source in a backlight unit, and may be easily processed by mirror processing. When applied to a light guide plate injection molding process or a press process using the mold made as described above, a uniform and stable pattern can be produced.

In addition, when the light guide plate is manufactured by using the mold thus manufactured, the light luminance transmitted from the side surface of the light guide plate is greatly improved, and the light source of the upper surface of the light guide plate is uniformly emitted upward in a straight line to obtain uniform high brightness. In addition, due to the brightness increase effect of the light guide plate, it is possible to reduce the additional device for improving the brightness is expected to reduce the cost.

Claims (8)

In the light guide plate of a flat panel display backlight, An upper surface of the light guide plate formed of a periodic pattern having an isosceles triangle inner angle A of the quadrangular pyramid from 50 ° to 60 ° and a square pattern length of the bottom of the square pyramid being 0.5 μm to 50 μm; A light guide plate integrated with a prism and a hologram pattern, comprising: a light guide plate lower surface formed of a non-periodic pattern having a square wave protrusion shape at regular intervals at one end of the other end of the light source at regular intervals. The method of claim 1, An isosceles triangle inner angle A of the quadrangular pyramid is 57.4 °. In the method of manufacturing a light guide plate of a prism and a hologram pattern integrated type, Forming a photoresist layer pattern on a silicon substrate, etching the patterned photoresist layer and the silicon substrate to form square pyramid irregularities, and electroplating the silicon substrate on which the square pyramid irregularities are formed to form a metal layer. Prismatic pattern mold portion comprising; and the step of separating the metal layer, and mirror surface processing of one side surface and the other pattern surface of the separated metal layer; Exposing the photoresist layer formed on the glass substrate with refractive interference light, forming a holographic pattern photoresist layer, electroplating the holographic pattern photoresist layer to form a metal layer, and A hologram pattern mold part comprising a separation step, and mirror-processing one side surface and the other end surface of the separated metal layer; The prism and hologram pattern integrated type of claim 1, wherein a material of any one of polymethyl metaacrylate (PMMA), polycarbonate (PC) or resin resin is inserted between the prism pattern mold part and the hologram pattern mold part to manufacture a light guide plate. Light guide plate manufacturing method. The method of claim 3, Prior to forming the metal layer, the light guide plate of the prism and hologram pattern integrated, further comprising applying a release agent mixed with potassium dichromate (K ₂ Cr ₂ O ₇ Potassium Dichromate) and ultrapure water (DI WATER). Manufacturing method. The method of claim 3, The isosceles triangle inner angle (A) of the square pyramid is a method of manufacturing a light guide plate integrated with a prism and a hologram pattern, characterized in that formed in 50 ~ 60 °. The method of claim 3, The square pattern length of the bottom of the square pyramid is a method of manufacturing a light guide plate integrated with a prism and a hologram pattern, characterized in that formed in 0.5 ~ 50㎛. The method of claim 3, The metal layer is a method of manufacturing a light guide plate integrated with a prism and a hologram pattern, characterized in that formed to a thickness of 0.3mm to 1cm. The method of claim 3, The metal layer may be formed of nickel, copper, tin, or chromium, or a light guide plate integrated with a prism and hologram pattern.

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