KR20080004880A - Color filter substrate, display panel having the color filter substrate and method of manufacturing the same - Google Patents

Abstract

A color filter substrate, a display panel having the color filter substrate and a method for fabricating the same are provided to increase the amount of output light compared with a case where light is polarized by a conductive wire grid pattern or a polarizer and then outputted. A base station includes defined unit pixel areas arranged in a matrix form. Color filters(130) are formed at each unit pixel area. A planarization layer(140) covers the base substrate(110) with the color filters(130) formed thereon. A wire grid pattern(150) includes a plurality of wire grid lines(151) formed at each unit pixel area on the planarization layer(140) and polarizes incident light. A light block pattern(120) is formed between the unit pixel regions to define recess portions of the color filters(130). An insulating layer covers the wire grid pattern(150). A transparent electrode is formed on the insulating layer.

Description

Color filter substrate, display panel having same and manufacturing method thereof {COLOR FILTER SUBSTRATE, DISPLAY PANEL HAVING THE COLOR FILTER SUBSTRATE AND METHOD OF MANUFACTURING THE SAME}

1 is a plan view of a color filter substrate according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the color filter substrate of FIG. 1 taken along the line II ′. FIG.

3 is a cross-sectional view of a color filter substrate according to an embodiment of the present invention.

4 is a plan view of a color filter substrate according to an exemplary embodiment of the present invention.

5 is a cross-sectional view of a display panel according to an exemplary embodiment of the present invention.

6, 7 and 8 are process diagrams of a method of manufacturing a color filter substrate according to an embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: color filter substrate 110: base substrate

120: light blocking pattern 130: color filter

140: planarization layer 150: grid pattern

151: grid 360: insulating layer

370 transparent electrode 600 display panel

601 array substrate 701 color filter substrate

The present invention relates to a color filter substrate, a display panel having the same, and a manufacturing method thereof. More specifically, the present invention relates to a color filter substrate, a display panel having the same, and a method of manufacturing the same, which reduce a decrease in contrast ratio due to light scattering.

In general, a liquid crystal display device has a thin thickness and a light weight, compared to a conventional CRT display device, and thus is widely used. However, since the liquid crystal display device displays an image using the liquid crystal layer as an optical shutter, it requires a linearly polarized light irradiated onto the liquid crystal display panel.

Polarizers are disposed on the front and rear surfaces of the liquid crystal display panel to change the randomly polarized light emitted from the backlight assembly into linearly polarized light. The polarizing plates and the liquid crystal layer control the amount of light emitted from the backlight assembly and control the polarization direction.

On the other hand, the light transmitted through the rear polarizing plate and the liquid crystal layer passes through the polarizing plate disposed on the front surface via the color filter. In order for the liquid crystal display panel to realize a black state or a white state, the light transmitted through the rear polarizer and the liquid crystal layer must be completely blocked or transmitted by the front polarizer. However, the light passes through the color filter before entering the front polarizer. The color filter includes pigment particles to scatter incident light. For this reason, the polarization direction of the polarized light controlled to be blocked or transmitted by the front polarizer is disturbed, and thus is not blocked or blocked by the front polarizer. In other words, the contrast ratio of the display panel is lowered.

In order to solve this problem, efforts have been made to increase the contrast ratio of the liquid crystal display panel by optimizing the size and shape of the pigment particles included in the color filter and surface treatment of the pigment particles, but it is a fundamental problem that light is scattered. This situation is difficult to solve.

Accordingly, the technical problem of the present invention is to solve such a conventional problem, and an object of the present invention is to provide a color filter substrate which prevents the contrast ratio from falling as the incident light is scattered by the color filter.

Another object of the present invention is to provide a display panel including the color filter substrate.

Still another object of the present invention is to provide a method of manufacturing the color filter substrate.

In order to achieve the above object of the present invention, the color filter substrate includes a base substrate, a color filter, a planarization layer, and a grid pattern. Unit pixel regions arranged in a matrix form are defined in the base substrate. The color filter is formed in each unit pixel region, and the planarization layer covers the base substrate on which the color filter is formed. The grid pattern includes a plurality of grid lines formed in each unit pixel area on the planarization layer to polarize incident light.

In order to achieve the above object of the present invention, a display panel according to an embodiment includes an array substrate, a color filter substrate, and a liquid crystal layer. The array substrate includes a lower base substrate having a plurality of unit pixel regions defined therein, a pixel electrode formed in each unit pixel region, and a switching element applying a pixel voltage to the pixel electrode. The color filter substrate includes an upper base substrate facing the lower base substrate, a color filter formed on the upper base substrate facing the pixel electrode, a planarization layer covering the upper base substrate on which the color filter is formed, and a planarization layer corresponding to each unit pixel region. It includes a wire grid pattern for polarizing the incident light including a plurality of grid lines formed in the. The liquid crystal layer is interposed between the array substrate and the color filter substrate.

According to another aspect of the present invention, there is provided a method of manufacturing a color filter substrate, the method including: forming a light blocking pattern on a base substrate, and forming a plurality of unit pixel regions defined by the light blocking pattern. Forming a color filter, forming a planarization layer covering the color filter and the light blocking pattern, and forming a plurality of grid lines on the planarization layer corresponding to the unit pixel areas.

According to such an array substrate, a display panel having the same, and a manufacturing method thereof, a display panel having improved contrast ratio and luminance can be provided.

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

Color filter board

1 is a plan view of a color filter substrate according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view of the color filter substrate of FIG. 1 taken along the line II ′. FIG.

1 and 2, the color filter substrate 100 includes a base substrate 110, a color filter 130, a planarization layer 140, and a grid pattern 150.

The base substrate 110 is made of glass having a plate shape, optically isotropic and excellent in light transmittance. The base substrate 110 defines a plurality of pixel regions arranged in a matrix form.

In the present embodiment, the color filter substrate 100 further includes the light blocking pattern 120. The light blocking pattern 120 is formed in the base substrate 110 in correspondence between the unit pixel regions, and defines a groove portion in which the color filter 130 to be described later is formed. The light blocking pattern 120 may be formed of a thin metal film such as chromium (Cr) or carbon-based organic material, such as an optical density of 3.5 or more. The light blocking pattern 120 is not limited to the above material and may be generally made of a pigment capable of absorbing light.

The color filter 130 is formed in the groove part, that is, each unit pixel area, and partially overlaps the light blocking pattern 120. The color filter 130 includes a red color filter, a green color filter, and a blue color filter. In the present embodiment, the red color filter, the green color filter, and the blue color filter are arranged in a stripe shape. In another embodiment, the red color filter, the green color filter and the blue color filter may be arranged in a moaic arrangement or a delta arrangement.

On the other hand, the color filter 130 is manufactured in a pigment (pigment) method or a dye (dye) method according to the material used, and is manufactured by a dyeing method, dispersion method, electrodeposition method, printing method and printing method and the like depending on the production method.

 When the color filter 130 is formed by the pigment dispersion method, the main components of the color photoresist used in the color filter 130 are, like a general photoresist, photosensitive initiators, monomers, binders, and the like, which are photosensitive compositions, and color. Pigments to embody.

 A photoinitiator is a highly sensitive compound which receives light and generate | occur | produces a radical, and a monomer becomes a polymer which does not melt | dissolve in a developing solution through a polymerization reaction by a radical. The binder protects the monomer in the liquid state from the developer at room temperature, and stabilizes the dispersion of the pigment and the reliability of heat resistance, light resistance, and chemical resistance of the color filter 130. The pigment is an organic particle having excellent light resistance and heat resistance, and scatters incident light.

Rayleigh scattering occurs when the size of the pigment particles is about 1/10 or less of the incident light wavelength, and Mie scattering occurs when the size of the pigment particles is about 1/10 or more of the incident light wavelength. Accordingly, the color filter 130 changes the polarized light in a specific direction incident to random polarized light.

The planarization layer 140 covers and protects the color filter 130 and the light blocking pattern 120. The planarization layer 140 compensates for the difference between the color filter 130 and the light blocking pattern 120 to provide a flat surface. The planarization layer 140 may include an acrylic resin, a polyamide resin, a polycarbonate resin, or the like having sufficient hardness and excellent light transmittance to protect the color filter 130 and the light blocking pattern 120.

The grid pattern 150 is formed on the planarization layer 140 to transmit only light having a specific polarization vector of incident light and reflect the rest. In the present embodiment, the grid pattern 150 includes a plurality of grid lines 151 formed in a stripe type. The grating lines 151 are made of a conductive metal, for example, aluminum (Al), molybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), chromium (Cr), silver (Ag), and the like. Can be.

 The direction in which the grid lines 151 are formed may be changed in various ways according to the design of the display panel in which the color filter substrate 100 is employed. For example, when the unit pixel area has a rectangular shape, the grid lines 151 may extend along the long side direction of the unit pixel area or may extend along the short side direction of the unit pixel area. Alternatively, the grid lines 151 may extend in a diagonal direction of the unit pixel area. The grid lines 151 may extend to neighboring unit pixel areas or may be intermittently formed in the pixel areas.

In general, the polarization using the grating line pattern 150 reflects the S-polarized light having a polarization vector parallel to the longitudinal direction of the grating lines 151 which are conductive lines, and in the longitudinal direction of the grating lines 151. P-polarized light having a vertical polarization vector is transmitted.

The polarization function of the grid pattern 150 is known to be influenced by the pitch defined by the interval between the centers of the grid lines 151 and the line width and height of the grid line 151. In addition, in order for the grating line pattern 150 to function as a polarizer, the pitch between the grating lines 151 should be smaller than the wavelength of incident light, and the pitch between the grating lines 151 is about 1/5 or less of the wavelength of the incident light. It is known to have an excellent degree of polarization. If the pitch between the grating lines 151 is longer than the wavelength of incident light, the grating line pattern 150 functions as a diffraction grating rather than a polarizer to diffract the incident light.

When the color filter substrate 100 is employed in the liquid crystal display panel, the liquid crystal display panel displays an image using visible light. Thus, the grid pattern 150 needs to have an excellent degree of polarization with respect to visible light. Since the wavelength of visible light is approximately 400 to 700 nanometers (nm), the pitch between the grating lines 151 is preferably 400 nanometers or less. The smaller the line width of the lattice lines 151 is preferable, but since the line width of the latest semiconductor process is about 50 nanometers and the space between lines and lines is required, in this embodiment, the pitch between the lattice lines 151 is 50 to 200 nanometers. It can be designed in meters (nm).

When P polarization is incident on the grid pattern 150 from the outside, the P polarization passes through the grid pattern 150. P-polarized light penetrates the planarization layer 140 and enters the color filter 130. Accordingly, the P-polarized light that has passed through the grid line pattern 150 or the P-polarized light polarized by the grid line pattern 150 is incident on the color filter 130 with little loss, and is scattered by the color filter 130 to cause red, Light expressed in green or blue is emitted through the base substrate 110.

Unlike the present embodiment, the grid pattern 150 is omitted on the planarization layer 140, and the polarizer or grid pattern 150 faces the one surface of the base substrate 110 on which the color filter 130 is formed. In the case of the color filter substrate 100 according to the comparative example formed on the surface, the P-polarized light incident on the planarization layer 140 from the outside is scattered by the color filter 130 to become random polarized light. The light scattered by the color filter 130 is polarized in the polarizer or grid pattern 150 disposed on the opposite surface, so that a considerable amount of light is lost. Therefore, it can be seen that the amount of light emitted from the color filter substrate 100 according to the present embodiment is significantly larger than the amount of light emitted from the color filter substrate 100 according to the comparative example.

3 is a cross-sectional view of a color filter substrate according to an embodiment of the present invention.

Referring to FIG. 3, the color filter substrate 300 includes a base substrate 310, a light blocking pattern 320, a color filter 330, a planarization layer 340, a grid pattern 350, and an insulating layer 360. And a transparent electrode 370. The color filter substrate 300 is the same as the color filter substrate 100 illustrated in FIGS. 1 and 2, except that the color filter substrate 300 further includes an insulating layer 360 and a transparent electrode 370.

The insulating layer 360 entirely covers the base substrate 310 on which the grid pattern 350 is formed, and provides a flat surface. The insulating layer 360 may include an acrylic resin, a polyamide resin, a polycarbonate resin, or the like having sufficient hardness to protect the grid pattern 350 and excellent in light transmittance and electrical insulation.

The transparent electrode 370 is entirely formed on the insulating layer 360. The transparent electrode 370 is formed of a transparent conductive material, and the transparent conductive material is indium-tin-oxide (ITO), indium-zinc-oxide (IZO), or indium- It may include tin-zinc oxide (Indium-Tin-Zinc-Oxide).

Unlike in the present embodiment, in another embodiment, the transparent electrode 370 is formed directly on the planarization layer 340, without forming the grid pattern 350 on the planarization layer 340, and then the transparent electrode 370. ) May be patterned to form stripe-type grating lines 351. In this case, the grating lines 351 are all connected to each other at a predetermined point to be electrically connected, and the grating lines 351 may simultaneously perform the function of one electrode of the liquid crystal capacitor and the polarizer function of polarizing incident light.

4 is a plan view of a color filter substrate according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the color filter substrate 500 includes a base substrate, a light blocking pattern 520, a color filter 530, a planarization layer, a grid pattern 550, an insulating layer, and a transparent electrode. The color filter substrate 500 is the same as the color filter substrate 300 shown in FIG. 3 except for the pitch of the grid lines 551.

In the present exemplary embodiment, the unit pixel region has a rectangular shape, and the grid lines 551 are formed in a stripe type extending in the long side direction of the unit pixel region. In addition, the pitch of the grid lines 551 is formed differently according to the unit pixel area.

Specifically, the pitch between the grating lines 551 formed in a unit pixel area is defined as a first pitch, and the pitch between the grating lines 551 formed in the unit pixel area adjacent to the short side direction with respect to the unit pixel area. When defined as the second pitch, the first pitch and the second pitch is formed differently. In this way, the pitch between the grid lines 551 may be adjusted according to the characteristics of the red, green, and blue color filters.

For example, in the case of the blue color filter, the shorter the wavelength of the incident light, the larger the Rayleigh scattering occurs. Therefore, it is desirable to filter the blue light having a relatively short wavelength among the light incident on the blue color filter. Accordingly, the red color filter, the green color filter, and the blue color filter are arranged along the short side direction, and color filters of the same color are arranged in the long side direction. The pitch between the grid lines 551 decreases in the order corresponding to the red color filter, the green color filter, and the blue color filter.

1 to 4 illustrate embodiments in which the unit pixel area has a rectangular shape. In another embodiment, the unit pixel area may have a zigzag curved shape. In this case, the grid lines 551 may also have a zigzag curved shape along the shape of the unit pixel area.

Display panel

5 is a cross-sectional view of a display panel according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the display panel 600 includes an array substrate 601, a color filter substrate 701, and a liquid crystal layer 800.

The array substrate 601 includes a lower base substrate 610 in which a plurality of unit pixel regions are defined, a pixel electrode 670 formed in each unit pixel region, and a switching element for applying a pixel voltage to the pixel electrode 670.

A switching element, for example, a thin film transistor (TFT), is formed in each unit pixel region. The thin film transistor includes a gate electrode 621, a gate insulating layer 630, a semiconductor layer 640, a source electrode 651, and a drain electrode 653.

The gate wiring extends along one side of the unit pixel region, and the gate electrode 621 protrudes from the gate wiring. The gate insulating layer 630 covers the gate wirings. The semiconductor layer 640 is formed on the gate insulating layer 630 corresponding to the gate electrode 621. The semiconductor layer 640 includes an amorphous silicon layer 641 and an amorphous silicon layer 643 doped with an n-type formed on the amorphous silicon layer. The source wiring extends along the other side of the unit pixel region, and the source electrode 651 protrudes from the source wiring and overlaps the upper portion of the semiconductor layer 640. The drain electrode 653 is spaced apart from the source electrode 651 and overlaps the semiconductor layer 640.

The array substrate 601 further includes a passivation layer 660 covering the thin film transistor.

The pixel electrode 670 is formed in the unit pixel area with a transparent conductive material. The pixel electrode 670 extends into a contact hole formed in the passivation layer 660 and is electrically connected to the drain electrode 653.

The array substrate 601 further includes a lower alignment layer 680 and a rear polarizer 690. The lower alignment layer 680 entirely covers the lower base substrate 610 on which the pixel electrode 670 is formed. The rear polarizer 690 is disposed on the rear surface of the array substrate 601.

The color filter substrate 701 of FIG. 3 is except that the upper alignment layer 780 is further formed on the common electrode 770 corresponding to the transparent electrode 370 of FIG. 3. Is substantially the same as

The liquid crystal layer 800 is interposed between the array substrate 601 and the color filter substrate 701.

Random polarized light incident on the rear surface of the array substrate 601 is polarized by the rear polarizer 690. The polarization direction transmitted through the pixel electrode 670 is controlled by the liquid crystal layer 800. In the case of a TN liquid crystal, the polarization axis of the polarization is rotated or maintained according to whether the liquid crystal molecules are in a twisted state.

The polarized light transmitted through the liquid crystal layer 800 is reflected or transmitted through the grid pattern 750 via the common electrode 770. The light polarized again in the grating pattern 750 is incident on the color filter 730 and is expressed as red, green, or blue light and exits through the upper base substrate 710.

Accordingly, the polarized light incident on the color filter 730 is not incident on the front polarizer after being scattered, but is polarized by the grid pattern 750 and then incident on the color filter 730 to be expressed as red, green, and blue light. . When the polarized light is incident on the front polarizer after being incident and scattered by the color filter 730, the contrast ratio of the display panel 600 is reduced. In contrast, in the present embodiment, the polarized light is incident on the color filter 730 after being polarized by the grid line pattern 750. In this case, even if the polarized light is scattered by the color filter 730, the contrast ratio is not lowered.

Color filter  Substrate Manufacturing Method

6, 7 and 8 are process diagrams of a method of manufacturing a color filter substrate according to an embodiment of the present invention.

6, 7 and 8, a method of manufacturing a color filter substrate may include forming a light blocking pattern 920 on a base substrate 910, and a plurality of unit pixels defined by the light blocking pattern 920. Forming a color filter 930 in the regions, forming a flattening layer 940 covering the color filter 930 and the light blocking pattern 920, and a flattening layer 940 corresponding to the unit pixel regions. Forming a plurality of grating lines 951 on the substrate.

Since the step of forming the planarization layer 940 on the base substrate 910 is a well known process, a detailed description thereof will be omitted.

After forming the planarization layer 940, as shown in FIG. 6, for example, aluminum (Al), molybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), and chromium (Cr). ), Silver (Ag), and the like, and the conductive metal layer 953 is deposited.

Next, the photoresist layer 960 is deposited on the conductive metal layer 953, and the photoresist layer 960 is exposed using a mask 901 having a pattern corresponding to the grid pattern 950. At this time, the pattern corresponding to the grid pattern 950 has a line width of about 50 to 200 nanometers (nm).

Subsequently, as illustrated in FIG. 7, the exposed photoresist layer 960 is developed to form a photoresist pattern 961 in which portions corresponding to the grating lines 951 remain, and the lattice is etched through an etching process. Lines 951 are formed.

Subsequently, as shown in FIG. 8, after the photoresist pattern 961 is removed through the strip process, the insulating layer 970 and the transparent electrode 980 are sequentially formed to complete the color filter substrate.

As described in detail above, according to the present invention, the light transmitted through the polarizing plate, the array substrate, and the liquid crystal layer is polarized by the conductive grid pattern before being scattered by the color filter. The polarized light is emitted through the color filter. Therefore, the amount of emitted light increases and the contrast ratio of the display panel increases compared with the case where the light is scattered by the color filter and then polarized by the conductive grid pattern or the polarizing plate.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (10)

A base substrate on which unit pixel regions arranged in a matrix form are defined; A color filter formed in each unit pixel area; A planarization layer covering a base substrate on which the color filter is formed; And And a wire grid pattern for polarizing incident light, including a plurality of grid lines formed in each unit pixel region on the planarization layer. The color filter substrate of claim 1, further comprising a light blocking pattern formed between the unit pixel areas to define a groove part in which the color filter is formed. The method of claim 2, An insulating layer covering the grid pattern; And The color filter substrate further comprises a transparent electrode formed on the insulating layer. The color filter substrate of claim 1, wherein the pitch between the grid lines is 50 to 200 nanometers (nm). The color filter substrate of claim 1, wherein a first pitch between grid lines formed in a unit pixel area and a second pitch between grid lines formed in a unit pixel area adjacent to the unit pixel area are different from each other. An array substrate including a lower base substrate having a plurality of unit pixel regions defined therein, a pixel electrode formed in each unit pixel region, and a switching element applying a pixel voltage to the pixel electrode; An upper base substrate facing the lower base substrate, a color filter formed on the upper base substrate facing the pixel electrode, a planarization layer covering the upper base substrate on which the color filter is formed, and the planarization corresponding to each unit pixel region A color filter substrate including a wire grid pattern for polarizing incident light including a plurality of grid lines formed on the layer; And And a liquid crystal layer interposed between the array substrate and the color filter substrate. The method of claim 6, wherein the color filter substrate A light blocking pattern formed on the upper base substrate corresponding to the unit pixel areas to define a groove part in which the color filter is formed; An insulating layer covering the grid pattern; And And a transparent electrode formed on the insulating layer. The display panel of claim 7, wherein the array substrate further comprises a polarizer disposed on a rear face of the lower base substrate. Forming a light blocking pattern on the base substrate; Forming a color filter in a plurality of unit pixel areas defined by the light blocking pattern; Forming a planarization layer covering the color filter and the light blocking pattern; And And forming a plurality of grid lines on the planarization layer corresponding to the unit pixel regions. The method of claim 9, further comprising: forming an insulating layer covering the grating lines; And Forming a transparent electrode on the insulating layer further comprising the method of manufacturing a color filter substrate.

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