KR20020028131A - Hologram diffuser of liquid crystal display and fabricating method thereof - Google Patents

Abstract

PURPOSE: A hologram diffuser of an LCD(Liquid Crystal Display) and a method for fabricating the same are provided to minimize the influence of the hologram diffuser due to the interference of light to improve a diffraction effect, so as to minimize a difference in local brightness of the LCD and improve a light transmission characteristic and a viewing angle. CONSTITUTION: A first resin(16) having a random concave-convex shape is hardened and formed on an upper part of a glass substrate(15). A second resin(19) having a plane upper surface is hardened on and in gear with an upper surface of the first resin(16). A third resin(21) is formed on an upper part of the second resin(19). A result of the formed resins is located on a heater and a nickel stamper is loaded on an upper part of the third resin(21), then is pressed using a roller at a temperature higher than a glass transition temperature. The nickel stamper is made to be located on an upper part of the heater, and ultraviolet rays are applied to pass from an ultraviolet lamp(25) to the glass substrate(15) to harden the third resin(21). The nickel stamper is separated. A ultraviolet hardened fourth resin(26) having a refraction index different from a refraction index of the third resin(21) is formed on an entire upper surface of a result of the separated nickel stamper and is planed, to apply ultraviolet rays from the ultraviolet lamp(25) to harden the fourth resin(26).

Description

Hologram diffuser of liquid crystal display and its manufacturing method {HOLOGRAM DIFFUSER OF LIQUID CRYSTAL DISPLAY AND FABRICATING METHOD THEREOF}

The present invention relates to a hologram diffuser of a liquid crystal display and a method of manufacturing the same, and in particular, by minimizing the influence of the hologram diffuser caused by light interference to improve the diffraction effect, thereby minimizing the local brightness difference of the liquid crystal display using the light transmission The present invention relates to a hologram diffuser of a liquid crystal display and a method of manufacturing the same, which are suitable for improving characteristics and viewing angles.

In general, various efforts have been made to secure a wide viewing angle of a liquid crystal display applied to a notebook computer, a monitor, or a television. Typically, an in-plane switching (IPS) method, a multi-domain ( multi domain method, cholesteric LC method, and method using hologram diffuser.

The IPS method is a method of forming an electrode horizontally on one side to align the liquid crystals in a vertical direction and then driving the liquid crystal through an electric field on a plane to improve the viewing angle. There is this.

The multi-domain method is a method of improving the viewing angle by varying the alignment angle according to the angle of aligning the liquid crystal into the multi-domain in the vertical direction, and the manufacturing process is complicated overall, and in particular, protrusions required for the alignment of the multi-domain. (Protrusion) is difficult to form, there is a disadvantage that the color difference between the side and the front.

The cholesteric liquid crystal method is a method of forming a polarizing plate and a color filter to improve the luminance by returning the reflected light by selectively transmitting and reflecting the light emitted from the light guide plate to the cholesteric liquid crystal, and the overall manufacturing process is complicated. In addition, there is a disadvantage in that the color difference between the side and the front.

In order to overcome the drawbacks described above, a method using a hologram diffuser has been proposed, and a method of using such a conventional hologram diffuser will be described in detail with reference to the accompanying drawings.

1A to 1C are process flowcharts for forming a holographic diffuser disc.

First, as shown in FIG. 1A, a photoresist 2 is formed on the glass plate 1, a spacer 3 having a predetermined thickness is formed on the photoresist 2, and the glass plate 4 interposed on the upper front surface is formed. The photoresist 2 of the region where the spacer 3 is not formed is photosensitive using a laser LASER.

As shown in FIG. 1B, the structure of the glass plate 1 and the photoresist 2 from which the inter glass plate 4 and the spacer 3 have been removed is developed in the developer 5.

Then, as shown in Fig. 1C, the photosensitive region of the photoresist 2 is developed by the development of Fig. 1B to form a disc having random irregularities.

2A to 2H are process flowcharts of forming a hologram diffuser using the disc of FIG. 1C.

First, as shown in FIG. 2A, a thin silver film is coated on the original plate of FIG. 1C, and then the silver plate 11 having the opposite shape of the original plate and the unevenness is formed by electroplating.

Then, as illustrated in FIG. 2B, the original plate is separated, and then nickel is formed on the silver plate 11 by electroplating to form a nickel plate 12 having the same shape as that of the original plate.

Then, as shown in FIG. 2C, the silver plate 11 is separated, and then nickel is formed on the nickel plate 12 by electroplating to form a nickel stamper 13 having opposite shapes of the original plate and the unevenness. Form.

Then, the nickel plate 12 is separated as shown in FIG. 2D.

As shown in FIG. 2E, a structure in which the glass plate 15 and the ultraviolet curable resin layer (resin) 16 are laminated on the heater 14 is formed, and the nickel stamper 13 is disposed on the resin layer 16. Put on, and press by the roller 17 at a temperature higher than the glass transition temperature (Tg) of the resin layer (16).

Then, as shown in FIG. 2F, the nickel stamper 13 is inverted to be positioned on the heater 14, and then ultraviolet rays are applied to penetrate the glass plate 15 from the ultraviolet lamp 18 to cure the resin layer 16. To reproduce the random uneven disc of FIG. 1C.

Then, the nickel stamper 13 is separated as shown in FIG. 2G.

As shown in FIG. 2H, an ultraviolet curable resin layer 19 having a refractive index different from that of the resin layer 16 is formed and planarized on the upper surface of the resultant in which the nickel stamper 13 is separated, and then the UV lamp 18 Ultraviolet rays are applied to cure the resin layer 19. At this time, it is preferable that the resin layer 16 is formed to have a larger refractive index than the resin layer 19.

However, the conventional method using the hologram diffuser as described above has the disadvantage that the light diffraction is isotropic as the hologram diffuser is formed to have random irregularities, so that the viewing angles of the upper and lower sides and the left and right sides are the same. In order to make a different, the configuration of a complex optical system is required in the process of forming the hologram, the manufacturing is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to minimize the influence of the hologram diffuser due to interference of light to improve the diffraction effect, thereby reducing the local brightness difference of the liquid crystal display using the same. The present invention provides a holographic diffuser of a liquid crystal display and a method of manufacturing the same, which can minimize and improve light transmission characteristics and viewing angles.

1A to 1C are process flowcharts for forming a disc of a conventional hologram diffuser.

2A to 2H are process steps for forming a conventional hologram diffuser using the disc of Fig. 1C.

3A to 3E are process flowcharts according to the first embodiment of the present invention.

Figures 4a to 4c is a process flowchart showing one embodiment of the disk formation for forming the second nickel stamper in the first embodiment of the present invention.

5A and 5B are graphs comparing light intensities at a far distance and a close distance of a resin layer having a regularly alternating rod-shaped pattern.

6A and 6B are graphs comparing diffraction angle distributions in the vertical direction and the left and right directions of a resin layer having a rod pattern that is constantly alternating.

7A to 7C are process flowcharts according to a second embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

15: glass plate 16, 19, 21, 26: resin layer

22: heater 23: nickel stamper

24: roller 25: UV lamp

The hologram diffuser of the liquid crystal display for achieving the object of the present invention as described above comprises a first resin layer cured on the upper portion of the glass plate and having a random uneven top surface; A hologram diffuser composed of a second resin layer having a top surface which is hardened to engage with the unevenness of the first resin layer, and has a flattened top surface. A third resin layer formed on the; And a fourth resin layer having a top surface which is cured and flattened to engage with the unevenness of the upper surface of the third resin layer.

The first embodiment of the method for manufacturing a hologram diffuser of a liquid crystal display for achieving the object of the present invention as described above is to form a first photoresist on the first glass plate and then subjected to selective photosensitive and development random irregularities Forming a disc to have a; Coating a silver film on the original plate and forming a silver plate having an opposite shape of the original plate and the unevenness by electroplating; Separating the original plate and then forming nickel on the silver plate by electroplating to form a nickel plate having the same shape as that of the original plate; Separating the silver plate and then forming nickel again on the nickel plate by electroplating to form a first nickel stamper having a shape opposite to that of the original plate and unevenness; After separating the nickel plate and forming a structure in which the second glass plate and the first resin layer is laminated on the heater, the first nickel stamper is placed on the first resin layer and higher than the glass transition temperature of the first resin layer. Pressing the roller at a temperature, curing the first resin layer, and separating the first nickel stamper to reproduce the irregularities of the original plate; In the step of forming, planarizing and curing a second resin layer having a different refractive index from the first resin layer, a third resin layer is formed on the second resin layer, placed on a heater, and then the third resin layer. Placing the second nickel stamper on the upper surface, pressing the roller at a temperature higher than the glass transition temperature of the third resin layer, curing the third resin layer, and separating the second nickel stamper; And forming a fourth resin layer having a refractive index different from that of the third resin layer on the resultant, and planarizing and curing the fourth resin layer.

The second embodiment of the manufacturing method of the hologram diffuser for achieving the object of the present invention as described above is to form a first photoresist on the first glass plate and then subjected to selective photosensitive and development to have random unevenness Forming a disc; Coating a silver film on the original plate and forming a silver plate having an opposite shape of the original plate and the unevenness by electroplating; Separating the original plate and then forming nickel on the silver plate by electroplating to form a nickel plate having the same shape as that of the original plate; Separating the silver plate and then forming nickel again on the nickel plate by electroplating to form a nickel stamper having opposite shapes of the original plate and the unevenness; After separating the nickel plate and forming a structure in which the second glass plate and the first resin layer is laminated on the heater, the nickel stamper is placed on the first resin layer at a temperature higher than the glass transition temperature of the first resin layer. Pressing the roller to harden the first resin layer, and removing a nickel stamper to reproduce the irregularities of the disc; Forming a second resin layer having a refractive index different from that of the first resin layer to planarize and then curing the first resin layer, wherein a third glass plate is formed on the second resin layer, and a photopolymer is formed on the third glass plate. Process; And performing a selective photosensitive process so that the photosensitive region and the non-photosensitive region of the photopolymer are constantly alternated.

The hologram diffuser of the liquid crystal display according to the present invention as described above and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

First, FIGS. 3A to 3E are process flowcharts of forming a hologram diffuser according to a first embodiment of the present invention.

Prior to applying the process according to the first embodiment of the present invention, the glass plate 15 through the process of Figures 2a to 2h using the process to form a disc of the holographic diffuser through the process of Figures 1a to 1c conventionally It is cured at the top to form a resin layer 16 having a random uneven top surface of the original, and a resin layer 19 having a flattened top surface is cured to engage with the unevenness of the top surface of the resin layer 16. .

As shown in FIG. 3A, a resin layer 21 is formed on the resin layer 19. As shown in FIG.

3B, the resultant is placed on the heater 22, and then a nickel stamper 23 is placed on the resin layer 21 at a temperature higher than the glass transition temperature of the resin layer 21. Press the roller 24 to take a picture.

Then, as shown in FIG. 3C, the nickel stamper 23 is inverted to be positioned on the heater 14, and then ultraviolet rays are applied to penetrate the glass plate 15 from the ultraviolet lamp 25 to cure the resin layer 21. Let's do it.

Then, the nickel stamper 23 is separated as shown in FIG. 3D.

3E, an ultraviolet curable resin layer 26 having a refractive index different from that of the resin layer 21 is formed and planarized on the upper surface of the resultant product from which the nickel stamper 23 is separated, and then the UV lamp 25 Ultraviolet rays are applied to cure the resin layer 26.

In this case, the nickel stamper 23 may be applied to the nickel stamper 13 formed in FIG. 2D again, and the resin layers 16 and 21 or the resin layers 19 and 26 may use the same materials. It is desirable to calculate and determine the desired diffraction effect in advance.

Alternatively, the nickel stamper 23 forms a photoresist 32 on the glass plate 31 as shown in FIG. 4A and then alternately alternates a rod-shaped first mask 33 as shown in FIG. 4B. Or through a second mask 34, and developed to form a disc made of a rod-shaped photoresist pattern 32 that is constantly alternating on the glass plate 31 as shown in FIG. 4C. Thus, by performing the processes of Figs. 2A to 2D in the related art, it can be formed to have a regular pattern of rods alternately.

When the resin layer 21 is formed through the nickel stamper 23 having such a regularly alternating rod-shaped pattern, the distance between the resin layers 16 and 21 is farther than the wavelength of light. As shown in FIG. 5B, the effect of the interference of light is reduced, as shown in FIG. It becomes like the pattern of the resin layer 21, and has the same light intensity. Therefore, there is no difference in brightness as a whole, and the diffraction effect is further increased.

In addition, when the resin layer 21 is formed through the nickel stamper 23 having a rod pattern that is constantly alternating, as shown in FIGS. 6A and 6B, the resin layer 21 is perpendicular to the horizontal direction of the pattern. The more diffraction of the light occurs in the direction, the different the diffraction distribution is. Therefore, it is possible to control the diffraction distribution in the vertical and horizontal directions by changing the rod shape and the refractive index of the resin layer 21 which are constantly alternating.

7A to 7C are process flowcharts for forming a hologram diffuser according to a second embodiment of the present invention.

First, prior to applying the process according to the second embodiment of the present invention, the original plate of the hologram diffuser is formed through the process of Figures 1a to 1c conventionally, and then using the glass plate (through the process of Figures 2a to 2h) 15) A resin layer 19 having a top surface which is cured to form a resin layer 16 having a top surface of a random uneven shape of a disc and engaged with the unevenness of the top surface of the resin layer 16 is formed. Form.

Then, as shown in FIG. 7A, a photopolymer 42 is formed on the glass plate 41, and then exposed through the first mask 33 or the second mask 34 shown in FIG. 4B to be shown in FIG. 7B. As described above, the photosensitive region 42A and the non-photosensitive region 42B of the photopolymer 42 form a structure in which the alternating regions are formed, and finally, as shown in FIG. 7C, the top surface of the resin layer 19 is formed. Attach to.

In this case, since the refractive indexes of the photosensitive region 42A and the non-photosensitive region 42B of the photopolymer 42 are different from each other, the same effects as those of the first embodiment of the present invention can be obtained.

As described above, the hologram diffuser of the liquid crystal display and the manufacturing method thereof according to the present invention can improve the diffraction efficiency by changing the refractive index of the resin layer to achieve a desired diffraction distribution, thereby ensuring a wide viewing angle and color change at the side surface. Therefore, there is an effect that can be minimized, and thus a clear contrast image can be obtained from the side of the liquid crystal display.

Claims (4)

A first resin layer cured on an upper portion of the glass plate and having a random upper and lower surface; A hologram diffuser composed of a second resin layer having a top surface which is hardened to engage with the unevenness of the first resin layer, and has a flattened top surface. A third resin layer formed on the; And a fourth resin layer having a top surface which is cured and flattened to engage with unevenness of the upper surface of the third resin layer. Forming a disc to have random unevenness by forming a first photoresist on the first glass plate and then performing selective photosensitive and developing processes; Coating a silver film on the original plate and forming a silver plate having an opposite shape of the original plate and the unevenness by electroplating; Separating the original plate and then forming nickel on the silver plate by electroplating to form a nickel plate having the same shape as that of the original plate; Separating the silver plate and then forming nickel again on the nickel plate by electroplating to form a first nickel stamper having a shape opposite to that of the original plate and unevenness; After separating the nickel plate and forming a structure in which the second glass plate and the first resin layer is laminated on the heater, the first nickel stamper is placed on the first resin layer and higher than the glass transition temperature of the first resin layer. Pressing the roller at a temperature, curing the first resin layer, and separating the first nickel stamper to reproduce the irregularities of the original plate; In the step of forming, planarizing, and curing a second resin layer having a different refractive index than the first resin layer, a third resin layer is formed on the second resin layer, placed on a heater, and then the third resin layer. Placing the second nickel stamper on the upper surface, pressing the roller at a temperature higher than the glass transition temperature of the third resin layer, curing the third resin layer, and separating the second nickel stamper; And forming and planarizing a fourth resin layer having a different refractive index than the third resin layer on the resultant, and then curing the hologram diffuser of the liquid crystal display. The method of claim 2, wherein the second nickel stamper comprises: forming a photoresist on a glass plate and then forming a disc having a rod-shaped photoresist pattern that is constantly altered through selective exposure and development; Coating a silver film on the original plate and forming a silver plate having an opposite shape of the original plate and the unevenness by electroplating; Separating the original plate and then forming nickel on the silver plate by electroplating to form a nickel plate having the same shape as that of the original plate; Separating the silver plate and then forming nickel again on the nickel plate by electroplating to form a nickel stamper having a shape opposite to that of the original plate and unevenness, wherein the holographic diffuser of the liquid crystal display is manufactured. Forming a disc to have random unevenness by forming a first photoresist on the first glass plate and then performing selective photosensitive and developing processes; Coating a silver film on the original plate and forming a silver plate having an opposite shape of the original plate and the unevenness by electroplating; Separating the original plate and then forming nickel on the silver plate by electroplating to form a nickel plate having the same shape as that of the original plate; Separating the silver plate and then forming nickel again on the nickel plate by electroplating to form a nickel stamper having opposite shapes of the original plate and the unevenness; After separating the nickel plate and forming a structure in which the second glass plate and the first resin layer is laminated on the heater, the nickel stamper is placed on the first resin layer at a temperature higher than the glass transition temperature of the first resin layer. Pressing the roller to harden the first resin layer, and removing a nickel stamper to reproduce the irregularities of the disc; Forming a second resin layer having a refractive index different from that of the first resin layer to planarize and then curing the first resin layer, wherein a third glass plate is formed on the second resin layer, and a photopolymer is formed on the third glass plate. Process; And subjecting the photosensitive region and the non-photosensitive region of the photopolymer to alternating photoresist uniformly.