KR20080109450A - Liquid crystal display panel with integrated microlens array and manufacturing mehtod of the same - Google Patents

Abstract

A liquid crystal display panel embodying a micro-lens and a method for manufacturing the same are provided to improve the brightness by reflecting light to the pixel region. A transparent substrate(10) includes a plurality of hemispherical lenses in single-side. An inorganic lens layer(60) is formed on the inorganic substance having the refractive index which is higher than the refractive index of the transparent substrate on the hemispherical lens with evaporation. An organic lens layer(70) is formed with the organic material having the refractive index lower than the inorganic lens layer. A transparent electrode is formed on the organic lens layer with evaporation.

Description

Liquid crystal display panel with microlens integrated and its manufacturing method {LIQUID CRYSTAL DISPLAY PANEL WITH INTEGRATED MICROLENS ARRAY AND MANUFACTURING MEHTOD OF THE SAME}

1 is a cross-sectional view of an upper substrate having a microlens array provided through a fabrication process integrated with the upper substrate proposed by the applicant of the present application but not yet disclosed;

Figure 2 is a cross-sectional view of the microlens integrated top substrate of one embodiment according to the present invention.

3 to 11 is an embodiment of a manufacturing process of a liquid crystal panel upper substrate according to the present invention.

12 to 14 is an embodiment of the manufacturing process of the liquid crystal panel upper substrate of an embodiment according to the present invention.

15 is a cross-sectional view of a liquid crystal display panel of one embodiment according to the present invention.

***** Brief description of the main symbols on the drawing *****

10: transparent substrate 20: high refractive material

30: space layer 50: counter electrode

60: inorganic lens layer 70: organic lens layer

80: photoresist 90: gray scale mask

100: upper substrate 200: lower substrate

300: liquid crystal layer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens integrated liquid crystal display panel and a method of manufacturing the same. More particularly, the present invention relates to a liquid crystal display panel including a microlens array composed of an inorganic layer and an organic layer and integrated therein.

The liquid crystal display device is a device for displaying an image by transmitting or blocking light from a pixel by using optical anisotropy of the liquid crystal. Such a liquid crystal display device includes a liquid crystal panel composed of a plurality of pixels. In the case of an XGA-class liquid crystal panel, the liquid crystal display device has a number of pixels having 1024 × 768 columns and rows. Each pixel is connected to a thin film transistor, which is a switching element, and a data signal for displaying an image and a line through which a scan signal is input cross vertically. The thin film transistor is positioned at the intersection point of the wiring to block or transmit light by applying or blocking an electric field to the liquid crystal by the switching operation of the thin film transistor.

The liquid crystal panel may be classified into a light blocking region and a light transmitting region. The light blocking region is a region in which a thin film transistor, which is a switching element for switching a liquid crystal, is formed, and means an area in which incident light is blocked. It can be defined as an area except the blocking area. The light transmissive region is also commonly referred to as the pixel region.

An area ratio occupied by a light transmission area among an area occupied by one pixel and an area occupied by the pixel in the liquid crystal panel is referred to as an aperture ratio. A liquid crystal panel having a high aperture ratio may provide a screen having improved luminance with the same power.

A method of attaching the microlens array to the liquid crystal panel as a method of increasing the luminance without substantially changing the aperture ratio has been proposed. In this case, the light incident to the light blocking region is refracted by the microlens array to be irradiated to the light transmitting region. Therefore, when using the same light source, more light is transmitted through the light transmission area, so that the image can be displayed brighter.

Conventionally, a method of bonding a microlens array manufactured through a separate manufacturing process from an upper substrate to an upper substrate is used. This conventional technique has difficulty in accurately aligning the microlens array and the upper substrate, and is also bonded. The adhesive used in this case has a problem that the viscosity of the microlens array and the array of the upper substrate are changed due to the change in viscosity depending on the temperature.

In order to solve the problems of the conventional method, a technique for implementing a microlens array integrated with an upper substrate has been proposed. However, the light refracted by the newly presented upper substrate and the microlens array integrated with the upper substrate does not become parallel light because the angle of refraction at the point of time emitted from the upper substrate and incident on the liquid crystal layer is not maintained, so the light emitted from the liquid crystal display panel There has been a problem in that efficiency is low when condensing with a projection lens.

An object of the present invention is to provide a microlens-integrated liquid crystal display panel and a method of manufacturing the same, wherein the light refracted by the microlens is incident on parallel light when incident on the liquid crystal layer. .

The object of the present invention is a transparent substrate having a plurality of hemispherical lenses on one surface, an inorganic lens layer formed of an inorganic material having a refractive index higher than the refractive index of the transparent substrate on the hemispherical lens, and the inorganic lens layer A microlens integrated liquid crystal display panel including an upper substrate including an organic lens layer formed of an organic material having a refractive index lower than that of the inorganic lens layer, and a transparent electrode deposited on the organic lens layer. Is achievable by

Still another object of the present invention is a method of manufacturing a liquid crystal display panel having a microlens integrated upper substrate, the method of manufacturing the upper substrate comprising the first step of preparing a transparent substrate, and applying a photoresist on the transparent substrate A second step; and a third step of forming a plurality of hemispherical recesses using the gray scale etching method; and dry etching the transparent photoresist to the transparent substrate using the formed plurality of recesses. A fourth step of etching forming a plurality of hemispherical recesses, a fifth step of depositing an inorganic lens layer having an index of refraction greater than that of the transparent substrate with an inorganic material on the transparent substrate on which the plurality of recesses are etched; A sixth step of spin coating an organic lens layer formed of an organic material on the inorganic lens layer and the organic lens layer Can be achieved by a method of manufacturing the microlens-integrated liquid crystal display panel characterized in that it comprises a seventh step of depositing a counter electrode formed on the unit.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display panel including a microlens integrated upper substrate, comprising: preparing a transparent substrate; and forming a polysilicon layer on the transparent substrate; Dry etching the silicon to form a plurality of preliminary recesses, and wet etching the plurality of preliminary recesses to the transparent substrate by using a hydrofluoric acid (HF) etchant to form the plurality of preliminary recesses. A fourth step of etching the grooves, a fifth step of depositing an inorganic lens layer having a refractive index greater than that of the transparent substrate with an inorganic material on the transparent substrate on which the plurality of concave grooves are etched, and an upper portion of the inorganic lens layer Spin coating an organic lens layer formed of an organic material on the substrate; and depositing and forming an opposite electrode on the organic lens layer. It can also be achieved by a method for manufacturing a microlens integrated liquid crystal display panel comprising seven steps.

Advantages, features and preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

  1 is a cross-sectional view of an upper substrate having a microlens array provided through an fabrication process integrated with the upper substrate proposed by the present applicant but not yet disclosed. The transparent substrate 10 used as the substrate of the upper substrate 100 is etched to form a groove, and the etched portion is filled with a high refractive material 20 having a higher refractive index than the transparent substrate 10 to form a lens. . Next, a space layer 30 having a refractive index similar to that of the transparent substrate 10 is stacked on the high refractive material layer 20. The space layer 30 functions to maintain a gap so that the light refracted by the high refractive material 20 may focus at a position separated by a desired distance. Finally, by forming the counter electrode 50 on the space layer 30, the upper substrate in which the microlens array is integrated is completed.

The microlens formed on the upper substrate should be hemispherical of sufficient size, and the high refractive material layer 20 should be formed relatively thick in order to form a sufficient hemisphere. The material had to be used. The reason is that the inorganic material is deposited as a thin film, so it has to go through several steps to obtain a sufficient thickness. Therefore, due to such economic problems, it is difficult to substantially form the lens layer only of the inorganic material.

The organic material can usually form a thickness of 1 μm to 3 μm by one spin coating, so that the desired microlens thickness can be easily achieved. However, in order to spin coat the organic material, a certain viscosity or more must be maintained, and in order to achieve the effect as a sufficient lens, the refractive index is higher than that of the transparent substrate. However, among the organic materials used in the industry, organic materials satisfying these conditions are difficult to find.

In addition, in the case of the microlens integrated upper substrate as shown in FIG. 1, even when the light refracted from the microlens array is emitted from the upper substrate and incident on the liquid crystal layer, the bending angle remains unchanged, so that parallel light cannot remain.

2 is a cross-sectional view of the microlens integrated upper substrate of one embodiment according to the present invention. The upper substrate 100 according to the present invention is laminated on a transparent substrate 10 having a plurality of hemispherical concave grooves, an inorganic lens layer 60 stacked on the transparent substrate 10, and an inorganic lens layer 60. The organic lens layer 70, the space layer 30 stacked on the organic lens layer 70, and the counter electrode 50 stacked on the space layer 30 are formed.

A glass substrate or a quartz substrate may be used as the transparent substrate 10, but in the present invention, a quartz substrate (quartz substrate) having a refractive index of 1.46 is used. On the transparent substrate 10, a plurality of hemispherical recesses are etched.

On the hemispherical recessed groove provided in the transparent substrate 10, the inorganic lens layer 60 is formed to be deposited to have a predetermined thickness along the recessed groove shape. The refractive index of the inorganic lens layer 60 is higher than the refractive index of the quartz substrate, but preferably has a refractive index of approximately 1.6 to 2.0. In the present invention, ITO (Indium Tin Oxide) is used as the material of the inorganic lens layer 60. When the refractive index of the inorganic lens layer 60 is larger than 2.0, the light passing through the upper substrate 100 may sometimes deviate from the upper BM region formed in the upper region of the lower substrate, and the light progresses after passing through the lens. The angle relative to the direction becomes too large and the amount of light incident on the projection lens is reduced, resulting in a decrease in efficiency. If the refractive index of the inorganic lens layer 60 is high and the refractive index difference with the transparent substrate 10 becomes large, the effective forcal length will be shortened based on Snell's law, but the angle of light after passing through the lens will be larger and projected. The problem of condensing by condensing in the system part arises. Preferably, the refractive index of the inorganic lens layer 60 is preferably maintained in the range of 1.6 to 2.0, and the thickness of the inorganic lens layer 60 to be deposited should be 0.3 μm to 1.0 μm for sufficient lens shape. When the thickness of the inorganic lens layer 60 is formed thinner than 0.3 mu m , sufficient lens effects do not occur and condensation is not performed. One preferable to form a lens thickness of the inorganic layer 60 is thicker than 1.0㎛ order to obtain a sufficient refractive effects, increased the permeability decreases and the step number corresponding to the thickness increase is a problem in terms of productivity. Therefore, the thickness of the inorganic lens layer 60 is preferably maintained to 0.3㎛ to 1.0㎛, more preferably 0.3 to 0.8㎛ thickness that can be solved by two to three times of deposition.

The organic lens layer 70 is formed of an organic material having a refractive index smaller than that of the inorganic lens layer 60, and preferably has a refractive index of 1.45 to 1.65, and the formation thickness is formed to have a thickness of 1 μm to 3 μm. It can be seen that the light refracted by the inorganic lens layer 20 is refracted into substantially parallel light by the organic lens layer 70 and is incident on the space layer 60. The thickness of the organic lens layer 70 may be freely adjusted according to the thickness of the space layer 30 formed in the following process and the focal length of the refracted light. A representative example of the material for forming the organic lens layer 70 is cyclotin (refractive index 1.5).

Space layer 30 is formed of a resin type, the refractive index has a range of 1.3 to 1.6, Tg (Glass Transitions Temperature / glass transition temperature) is more than 250 ℃, crack free, physical strength of high compression strength A material having properties was selected. The coating thickness of the space layer 30 was 15 μm to 70 μm, and was formed in a multi-layered structure. Substantial thickness of the space layer 30 was the refractive index and the thickness of the inorganic lens layer 60 and the organic lens layer 70. Is designed according to.

It is preferable that the refractive index of the space layer 30 has a lower refractive index than the inorganic lens layer 60, and more preferably, the refractive index is higher, so that the heat resistance is lowered, so that the refractive index has a range of about 1.4 to 1.5, similar to the quartz. good.

In addition, since the temperature rises to about 250 ° C. in the ITO alloy step or the alignment layer processing step in the future, the space material preferably has a curing temperature as high as possible, and in the present invention, a curing temperature of about 250 ° C. Space material having was used. More preferably, the glass transition temperature of the space layer 30 is 300 ° C. or more in order to obtain sufficient ITO characteristics.

Representative materials of the space layer 30 were BCB (bisbenzocyclobutene) -based Dow Chemical's cyclotene and Samyang EMS's OCE-1010. The two kinds of materials are insulators used by general a-Si TFT companies to improve the aperture ratio between the metal wiring and the counter electrode, and are generally called an overcoat material.

In the upper substrate 100 of the liquid crystal display panel according to the present invention, when the organic lens layer 70 is thickly formed, the process of forming the space layer 30 may be omitted. However, the space layer 30 reduces the case where the organic lens layer 70 is directly exposed to high temperature, and can be formed by an easier spreading method than the organic lens layer 70, so that the organic lens layer 70 and the opposite electrode are formed. It is preferable to interpose in between.

3 to 11 are exemplary embodiments of a manufacturing process of a liquid crystal panel upper substrate according to the present invention. The photoresist 80 is applied onto a transparent substrate 10 such as a quartz substrate (Figs. 3 and 4).

Thereafter, the coated photoresist 80 is exposed and developed by a gray scale photolithography method using a gray scale mask 90 to form a concave lens (FIGS. 5 and 6). In the gray scale light etching method, a desired lens shape may be realized by varying the degree of development using the gray level of light during exposure.

At this time, the lens center of the concave lens shown in the drawing should be located above the center (approximately the center of the pixel) of the region through which the light of the lower substrate is transmitted.

The photoresist 80 formed in a lens shape is dry etched to the transparent substrate 10 so that a plurality of lens shapes 15 are formed on the transparent substrate 10 (FIG. 7). Next, the inorganic lens layer 60 is deposited by two to three chemical vapor deposition (CVD) methods (FIG. 8). It can be seen that the deposited inorganic lens layer 60 is formed along the concave lens shape without being flattened at the top.

Next, the organic lens layer 70 is formed on the inorganic lens layer 60 by spin coating (FIG. 9). Since the organic lens layer 70 is formed by a spin coating method, the organic lens layer 70 may be formed in a flat plane.

The space layer 30 is spread over the organic lens layer 70 (FIG. 10). The steps of spreading the space material will be briefly described.

As a first step, rinse and pretreat the substrate with a suitable activator as needed to improve the coating. As a second step, back-side rinse after spin coating by dispensing material onto a substrate rotating at hundreds to thousands of RPMs by a preset program using a material of viscosity designed appropriately for the target thickness. ) And Edge-Bead Removal (EBR). As a third step, bake for about 20 to 300 seconds (varies with temperature) on a hot plate at 60 ° C to 200 ° C, to prevent the flow of the space layer 30 during processing. The solvent is blown off. As a fourth step, soft cure is carried out in an inert atmosphere (N ₂ atmosphere) as necessary at a temperature of 150 ° C to 250 ° C for 20 to 60 minutes. If a multi-layer coating is needed as the fifth step, the second to fourth steps are repeated.

Next, a counter electrode 50 is deposited on the space layer 30 to a thickness of about 600 m 3 (FIG. 11). In the present invention, since the space layer 30 is formed of a resin series that melts at 250 ° C. or higher, ITO applies a deposition process at room temperature (LT process, Low Temperature process). As a result of the measurement, the counter electrode 50 deposited by the LT process was found to have no significant difference from the existing high temperature ITO deposition process in terms of electrical resistance and transmittance. Even if the remaining ITO alloy process and the alignment film treatment process were performed as they are at high temperature, there was no problem of discoloration or bubbles formed in the conventional synthetic resin adhesive in the space material. This is because the adhesive used for bonding the MLA lens to the upper substrate has a low melting point, whereas the space of the present invention forms a melting point at 250 ° C., thus, a baker process of ITO alloy or an alignment layer, which is a later high temperature process, is performed. It is analyzed for reasons without material limitations to proceed.

Although the dry etching using the gray scale mask was performed in the process of FIG. 3 to FIG. 11, the wet etching using hydrofluoric acid (HF) may be performed instead of the dry etching. 3 to 11 are different from those of wet etching using hydrofluoric acid (HF) in the processes of FIGS. 4 to 6. Instead of the process of FIG. 4, as shown in FIG. 12, a polysilicon layer 180 is formed on the transparent substrate 10. Thereafter, as shown in FIG. 13, the preliminary recesses 185 having a radius smaller than the radius size of the desired recesses are regularly formed by dry etching. Next, when wet etching is performed using the fluorine (HF) etching solution, the fluorine etching solution does not react to the polysilicon layer 180 and only the transparent substrate 10 is etched at an equidistant distance, thereby forming a plurality of lens shapes 15 as shown in FIG. 14. A transparent substrate 10 having) is formed. When the polysilicon layer 180 remaining after the wet etching is removed through wet etching using a mixed solution of nitric acid and hydrofluoric acid (HF), the transparent substrate 10 as shown in FIG. 7 may be formed. In this case, since the transparent substrate 10 is provided with a quartz substrate, equidistant etching by fluorine can be performed more preferably. 8 to 11 are performed in the same process.

In the wet etching using the fluorine, a photoresist used in a conventional optical etching process cannot be used. This is because fluorine has a property of etching to a photoresist.

15 is an embodiment of a liquid crystal display panel according to the present invention. The liquid crystal display panel is formed of the upper substrate 100 and the lower substrate 200 and the liquid crystal layer 300 injected therebetween. The microlens array described above is integrally formed on the upper substrate 100, and an opposite electrode and an alignment layer are formed. The lower substrate 200 includes a switching element, a storage capacitor, and an alignment layer. A liquid crystal display panel is completed by bonding the upper substrate 100 and the lower substrate 200 on which the alignment film processing is completed and injecting liquid crystal therebetween.

According to the liquid crystal panel with a microlens array according to the present invention and a method of manufacturing the liquid crystal panel, the brightness of the liquid crystal panel can be refracted to the pixel region by forming the microlens array directly on the upper substrate of the liquid crystal panel. To increase.

According to the liquid crystal panel including the microlens array according to the present invention and a method of manufacturing the same, since the adhesive of synthetic resins is not used in the manufacture of the microlens array, the ITO alloy process and the alignment film treatment can be performed at a high temperature.

In addition, since the resin adhesive is not used, the microlens array can be easily cut. Therefore, the manufacturing method which cut | disconnects a microlens array in a post process after attaching a microlens array to the liquid crystal panel provided with a TFT element became possible.

In the case of adjusting the thickness of the space or the high refractive layer, there is an advantage of not having to attach a separate dustproof substrate. Therefore, it is possible to simplify the manufacturing process of the microlens array by omitting the process of attaching the anti-vibration substrate, and solve the problem of poor transmittance by the adhesive.

Finally, when a design change occurs in an optical system portion including a projection lens or the like, there is an advantage that the present invention can be easily changed by adjusting the thickness of a space or a high refractive layer.

While the preferred embodiments of the present invention have been described using specific terms, such descriptions are for illustrative purposes only, and it is understood that various changes and modifications may be made without departing from the spirit and scope of the following claims. Should be done.

Claims (12)

A transparent substrate having a plurality of hemispherical lenses on one surface, An inorganic lens layer formed by depositing an inorganic material having a refractive index higher than that of the transparent substrate on the hemispherical lens; An organic lens layer formed on the inorganic lens layer and formed of an organic material having a refractive index lower than that of the inorganic lens layer, and A microlens integrated liquid crystal display panel comprising an upper substrate including a transparent electrode deposited on the organic lens layer. The method of claim 1, And a spacing layer laminated between the organic lens layer and the transparent electrode. The method according to claim 1 or 2, The refractive index of the inorganic lens layer has a range of 1.6 to 2.0 microlens integrated liquid crystal display panel. The method according to claim 1 or 2, And the inorganic lens layer is formed of indium tin oxide (ITO). The method according to claim 1 or 2, The inorganic lens layer is a microlens integrated liquid crystal display panel, characterized in that formed by depositing 0.3㎛ to 1.0㎛ thickness. The method of claim 2, The space layer has a glass transition temperature of 250 ℃ or more microlens integrated liquid crystal display panel. The method of claim 2, The space layer has a microlens integrated liquid crystal display panel, characterized in that it has a refractive index of 1.3 to 1.6. The method according to claim 1 or 2, The organic lens layer is a microlens integrated liquid crystal display panel, characterized in that formed by spin coating method of an organic material of 1㎛ to 3㎛ thickness having a refractive index of 1.45 to 1.65. A manufacturing method of a liquid crystal display panel having a microlens integrated upper substrate, wherein the manufacturing method of the upper substrate is A first step of preparing a transparent substrate; A second step of applying a photoresist on the transparent substrate; A third step of forming a plurality of hemispherical concave grooves on the photoresist using gray scale etching; Dry etching the transparent substrate to the transparent substrate using the formed plurality of concave grooves to etch and form a plurality of hemispherical concave grooves on the transparent substrate; Depositing an inorganic lens layer having an index of refraction greater than that of the transparent substrate with an inorganic material on the transparent substrate on which the plurality of concave grooves are etched; A sixth step of spin coating an organic lens layer formed of an organic material on the inorganic lens layer; And And depositing and forming a counter electrode on the organic lens layer, wherein the microlens-integrated liquid crystal display panel is manufactured. A method of manufacturing a liquid crystal display panel having a microlens integrated upper substrate, A first step of preparing a transparent substrate; Forming a polysilicon layer on the transparent substrate; Dry etching the polysilicon to form a plurality of preliminary recesses; A fourth step of wet etching the transparent substrate using the hydrofluoric acid (HF) etching solution in the formed plurality of preliminary recesses, and etching the plurality of hemispherical recesses in the transparent substrate; Depositing an inorganic lens layer having an index of refraction greater than that of the transparent substrate with an inorganic material on the transparent substrate on which the plurality of concave grooves are etched; A sixth step of spin coating an organic lens layer formed of an organic material on the inorganic lens layer; And And depositing and forming a counter electrode on the organic lens layer, wherein the microlens-integrated liquid crystal display panel is manufactured. The method according to claim 9 or 10, And an eighth step of forming a space layer on the organic lens layer between the sixth step and the seventh step. The method according to any one of claims 9 to 11, The inorganic lens layer is formed of ITO (Indium Tin Oxide) by a chemical vapor deposition method of 0.3㎛ to 1.0㎛ thickness characterized in that the microlens integrated liquid crystal display panel manufacturing method.

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