KR20070074194A - Display panel - Google Patents

Abstract

A display panel is provided to form a color filter layer by means of a dichroic mirror, thereby enhancing the light transmission rate of the second substrate. Signal lines are formed at the first substrate(211) and supplies an image signal to each pixel. The second substrate(212) is fixed oppositely to the first substrate so that a liquid crystal layer is received. The second substrate includes a base substrate(240). The first color filter layer is formed on the base substrate and intercepts the light beam except for the color represented from each pixel among the white light beam components. The second color filter layer is formed on the base substrate and intercepts the light beam with the color represented from each pixel among the white light beam components and except for the color intercepted by the first color filter layer. The first color filter layer is formed at the first surface of the base substrate and the second color filter layer is formed at the second surface of the base substrate as the rear surface of the first surface.

Description

Display panel {DISPLAY PANEL}

1 is an exploded perspective view schematically illustrating a display device according to an exemplary embodiment of the present invention.

FIG. 2 is a plan view illustrating the display panel illustrated in FIG. 1.

3 is a cross-sectional view of a portion of the display panel illustrated in FIG. 2;

4 is a view for explaining the light transmission of the second substrate shown in FIG.

Explanation of symbols on the main parts of the drawings

100: display device 200: display panel assembly

210: display panel 211: first substrate

212: second substrate 240: base substrate

241: light blocking layer 242: first color filter layer

243: second color filter layer 300: backlight assembly

400: mold frame 500: storage container

600: top chassis

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display panel, and more particularly, to a display panel having improved light transmittance and improved display quality.

In general, the display device may be defined as a device that displays a predetermined image so that a user may recognize data processed by the information processing device. Such display devices are widely used for flat panel display devices for small size, light weight, high resolution, and full color.

A liquid crystal display device is one of such display devices, in which a liquid crystal material having dielectric anisotropy is injected between two substrates to apply an electric field, and the amount of light transmitted is controlled by controlling the intensity of the electric field. A display device for displaying an image.

In general, a liquid crystal display device includes a liquid crystal display panel for displaying an image.

The liquid crystal display panel includes a first substrate having a thin film transistor (TFT) array as a switching element, a second substrate opposed to the first substrate, and a liquid crystal layer interposed between the two substrates.

The first substrate has a plurality of data lines and gate lines that cross each other, and a pixel portion is formed in each region where the data lines and gate lines cross.

Each pixel portion has a TFT, a liquid crystal capacitor and a storage capacitor. The first electrode of the liquid crystal capacitor is a pixel electrode connected to the drain electrode of the TFT, and the second electrode is a common electrode formed on the second substrate. In addition, the first electrode of the storage capacitor is a pixel electrode connected to the drain electrode of the TFT, and the second electrode is a common electrode formed on the first substrate.

When the gate signals input to the gate lines are applied to the gate electrode of the TFT and the TFT is turned on, the data signals applied to the data lines are the first electrodes of the liquid crystal capacitors through the source electrode of the TFT. Applied to the pixel electrode.

Meanwhile, after the data signals are applied to the first electrodes of the storage capacitors, a constant DC voltage, that is, a common voltage, is applied to the second electrodes of the storage capacitors to maintain the potential level of the data signals. Accordingly, charge is charged in the liquid crystal capacitors and the storage capacitors by the data signals applied to the liquid crystal capacitor and the data signals stored in the storage capacitors, and the arrangement angle of the liquid crystal material is changed according to the charge rate of the charge. The image is displayed on the liquid crystal panel by the light transmitted or reflected by the liquid crystal material having the changed alignment angle.

In this case, the second substrate is generally formed with a light shielding layer that partitions each pixel portion on the base substrate, and red, green, and blue photosensitive polymer organic materials are spin-coated for each region corresponding to each pixel portion on the top of the light shielding layer. by coating) or the like to form a color filter layer.

Therefore, the light transmitted or reflected through the liquid crystal material is expressed in a predetermined color by the color filter layer.

However, such a color filter layer is formed of a photosensitive high molecular organic material such as a color register to reduce the transmittance of the liquid crystal display panel. This has a problem of causing a decrease in luminance of the liquid crystal display panel in proportion to the transmittance.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a display panel with improved display quality by improving the transmittance of the display substrate.

In order to achieve the above object, the display panel according to an exemplary embodiment includes a first substrate and a second substrate. In a display panel in which a plurality of pixel parts are formed and an image is displayed using white light in which red, green, and blue light are mixed in color, the first substrate includes signal wires for providing an image signal to each pixel part. The second substrate is opposed to the first substrate to accommodate the liquid crystal layer.

In addition, the second substrate is formed on the base substrate, the first color filter layer which is formed on the base substrate and blocks light transmission of one color other than the color expressed in each pixel of the white light component, and is formed on each pixel of the white light component. And a second color filter layer that blocks light transmission other than the color to be expressed and the color blocked by the first color filter layer.

In this case, the first color filter layer may be formed on the first surface of the base substrate, and the second color filter layer may be formed on the second surface that is the rear surface of the first surface. In addition, the first and second color filter layers may be formed on the same surface of the base substrate.

Here, each color filter layer is formed of dichroic mirrors that block light transmission of different colors.

The second substrate may further include a light blocking layer partitioning each pixel and a common electrode layer providing a common voltage to each pixel.

According to the display panel, the light transmittance of the second substrate can be improved as compared with forming the color filter layer on the second substrate by the photosensitive polymer organic material, thereby improving the luminance of the display panel and improving the display quality of the display panel. can do.

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

1 is an exploded perspective view schematically illustrating a display device according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the display device 100 according to an exemplary embodiment includes a display panel assembly 200, a backlight assembly 300, a mold frame 400, and a storage container 500. In addition, the display device 100 according to an exemplary embodiment may further include a top chassis 600.

The display panel assembly 200 includes a display panel 210 and a driving unit 220.

The display panel 210 includes a first substrate 211, a second substrate 212 opposite to the first substrate 211, and a liquid crystal layer interposed between the first substrate 211 and the second substrate 212. Not shown). The liquid crystal layer is composed of liquid crystal molecules having electrical and optical characteristics such as dielectric anisotropy. For example, the liquid crystal molecules included in the liquid crystal layer are twisted nematically inclined at a predetermined angle in response to an electric field formed by a pixel voltage applied to the first substrate 211 and a common voltage applied to the second substrate 212. (Twist Nematic) It may be made of liquid crystal molecules.

The display panel 210 displays a predetermined image using the liquid crystal layer and the light emitted from the backlight assembly 300.

More detailed description of the display panel 210 will be described in detail with reference to FIGS. 2 to 4.

The driving unit 220 includes a data side TCP (Tape Carrier Package) 221 for outputting a data signal to the display panel 210, a gate side TCP 222 and a printed circuit board 223 for outputting a gate signal. .

In the data side TCP 221, a data driving chip 221a for converting and outputting a digital data signal provided from a host system (not shown) such as an external graphic controller to an analog data signal may be mounted. A gate driving chip 222a for sequentially outputting a gate signal may be mounted on the gate side TCP 222.

The printed circuit board 223 is electrically connected by the data side TCP 221 and the anisotropic conductive film (ACF), and a driving chip (not shown) for generating a timing signal for controlling the driving timing of the data signal and the gate signal. And a timing signal lamp to the data side and gate side TCPs 221 and 222.

In the exemplary embodiment of the present invention, only one printed circuit board 223 electrically connected to the data side TCP 221 is illustrated, but the printing is electrically connected to the gate side TCP 222 to control the driving timing of the gate signal. It may be formed by further including a circuit board.

The backlight assembly 300 includes a lamp 310, a lamp cover 320, a light guide plate 330, a reflective sheet 340, and optical sheets 350.

The lamp 310 may be configured as, for example, an elongated cylindrical cold cathode fluorescent lamp (CCFL). In addition, the light emitting diode may be configured in various ways. The lamp 310 generates light having a predetermined brightness in response to a driving voltage applied from an external inverter (not shown).

In this case, the light emitted from the lamp 310 is white light to which white color coordinates are applied by mixing red, green, and blue light with false color.

The lamp cover 320 is disposed on one side while surrounding the lamp 310 and protects the lamp 310 from external impact. In addition, the lamp cover 320 may be configured to reflect the light generated from the lamp 310 toward the light guide plate 330 in order to improve the brightness characteristic of the light. In this case, the lamp cover 320 may include a reflector reflecting light emitted from the lamp 320.

The light guide plate 330 converts the light supplied from the lamp 310 disposed at the side into light of a surface light source and emits the light. To this end, a printing pattern for diffusing and reflecting light may be formed on the lower surface of the light guide plate 330 or a prism pattern may be formed. The light guide plate 330 is made of a transparent material to minimize the loss of light. For example, the light guide plate 330 may be made of polymethyl methacrylate (PMMA) having excellent strength.

The reflective sheet 340 is disposed under the light guide plate 330, and reflects light leaking to the outside through the bottom surface of the light guide plate 330 toward the light guide plate 330 to improve light utilization efficiency. The reflective sheet 340 is made of a material having high light reflectance. For example, the reflective sheet 340 may be made of white polyethylene terephthalate (PET) or polycarbonate (PC).

The optical sheets 350 improve brightness characteristics of light emitted from the light guide plate 330. The optical sheets 350 may include a diffusion sheet to diffuse light emitted from the light guide plate 330 to improve luminance uniformity. In addition, the optical sheets 350 may include a prism sheet for condensing the light emitted from the light guide plate 330 in the front direction to improve the front brightness of the light.

Meanwhile, optical sheets having various functions may be added to or removed from the backlight assembly 300 according to required luminance characteristics.

The mold frame 400 is coupled to the storage container 500 to fix the backlight assembly 300. The mold frame 400 is coupled to the sidewall of the storage container 500 while pressing the edges of the top surfaces of the optical sheets 350. Therefore, the mold frame 400 fixes the backlight assembly 300 and supports the display panel 210 to be disposed on the backlight assembly 300.

The storage container 500 accommodates the backlight assembly 300 and the mold frame 400. To this end, the storage container 500 includes a bottom surface covering the bottom of the backlight assembly 300 and sidewalls extending from an edge of the bottom surface to prevent the backlight assembly 300 and the mold frame 400 from flowing. The storage container 500 may be formed of a chassis material.

The top chassis 600 is coupled to the storage container 500 to fix the display panel 210 to the upper portion of the backlight assembly 300. The top chassis 600 includes a bezel portion 610 and sidewalls 620. Here, the bezel part 610 is a rectangular edge that exposes the effective display area of the display panel 210 to the outside. The sidewall 620 is bent from an edge of the bezel part 610 to be coupled to the storage container 500 to prevent the display panel 210 from flowing.

2 is a plan view illustrating the display panel 210 illustrated in FIG. 1, and FIG. 3 is a cross-sectional view of a portion of the display panel 210 illustrated in FIG. 2, and FIG. A diagram for describing the light transmission of the illustrated second substrate 212.

Referring to FIG. 2, the display panel 210 according to an exemplary embodiment of the present invention includes a first substrate 211 and a second substrate 212.

The m data lines DL1 to DLm and the n gate lines GL1 to GLn crossing the data lines DL1 to DLm insulated from each other are formed on the first substrate 211. Where m and n are natural numbers. Thin film transistors (TFTs) are formed in regions where the data lines DL1 to DLm and the gate lines GL1 to GLn cross each other.

For example, the first switching element TFT1 and the first pixel electrode PE1 are formed in an area where the first data line DL1 and the first gate line GL1 cross each other. The gate electrode of the first switching element TFT1 is connected to the first gate line GL1, the source electrode of the first switching element TFT1 is connected to the first data line DL1, and the first switching element TFT1 ) Is connected to the pixel electrode PE.

In the same manner, the switching element TFT and the pixel electrode PE are formed in each of the regions where the second to mth data lines DL2 to DLm and the second to nth gate lines GL2 to GLn cross each other.

Referring to FIG. 3, the first substrate 211 includes a base substrate 230, a TFT array layer 231, and a pixel electrode layer 232.

The base substrate 230 is made of a transparent insulating material such as glass or polycarbonate (PC).

The TFT array layer 231 is formed on the base substrate 230. The TFT array layer 231 includes a plurality of TFTs, a protective film 233, and a planarization film 234.

Each of the plurality of TFTs includes a gate electrode 235a, a gate insulating film 235b, an active layer 235c, an ohmic contact layer 235d, a drain electrode 235e, and a source electrode 235f.

The protective film 233 is made of an organic insulating film covering a plurality of TFTs.

The planarization layer 234 is formed of an organic insulating layer formed on the passivation layer 233 to planarize the first substrate 211.

In the passivation layer 233 and the planarization layer 234, a contact hole CTH is formed to expose the drain electrode 235e of the TFT.

The pixel electrode layer 232 is made of a transparent conductive material, for example, indium tin oxide (ITO), and is formed on the planarization layer 234 in a region corresponding to each pixel. A predetermined pattern is formed on the pixel electrode layer 232 to form the pixel electrode PE of each pixel.

The second substrate 212 is opposed to the first substrate 211 to accommodate the liquid crystal layer 250.

The second substrate 212 includes a base substrate 240, a light blocking layer 241, a first color filter layer 242, and a second color filter layer 243.

The base substrate 240 is made of a transparent insulating material such as glass or polycarbonate (PC).

The light blocking layer 241 is formed on the base substrate 240 at a position corresponding to the TFT, the data line DL, and the gate line GL, and passes through liquid crystal in a region not controlled by the pixel electrode PE. Is blocked to improve the contrast ratio of the display panel 210.

To this end, the light shielding layer 241 is formed of a metal thin film such as chromium (Cr) or a carbonate-based organic material on the base substrate 240, and for the purpose of low reflection, chromium / chromium oxide (Cr / It may be formed of a two-layer film structure such as CrOx).

The light blocking layer 241 is formed as the first light blocking layer 241a and the second light blocking layer 241b when the first color filter layer 242 and the second color filter layer 243 are formed on both surfaces of the base substrate 240, respectively. Can be formed separately. In addition, when the first color filter layer 242 and the second color filter layer 243 are stacked on one surface of the base substrate, they may be formed as one light blocking layer.

The first color filter layer 242 is formed in a region where the light blocking layer 241 is not formed on the base substrate. For example, the first color filter layer 242 is formed by a dichroic mirror. Here, the dichroic mirror forms a prism row on a transparent flat plate to selectively reflect light of a predetermined wavelength from white light in which three primary colors, that is, red, green and blue light are synthesized, and transmits the remaining red, green and It is an optical member which isolates blue light.

In this case, the first color filter layer 242 is configured of a dichroic mirror reflecting different colors for each pixel PA1, PA2, and PA3.

For example, when the first pixel PA1 is a pixel expressing red light, the color filter included in the first pixel PA1 reflects a blue dichroic mirror B or green light that reflects blue light. It may be formed of a green dichroic mirror (G).

In addition, when the second pixel PA2 is a pixel expressing green light, the color filter included in the second pixel PA2 may be a red dichroic mirror R reflecting red light or a blue light reflecting blue light. It may be formed of a dichroic mirror (B).

Similarly, when the third pixel PA3 is a pixel expressing blue light, the color filter included in the third pixel PA3 may be formed of the green dichroic mirror G or the red dichroic mirror R. Can be.

The first color filter layer 242 may be formed on the base substrate 240 through various methods such as coating a dichroic mirror before and after forming the light blocking layer 240.

The reflection and transmission of light by the first color filter layer 242 will be described below.

Referring to FIG. 4, the first color filter layer 242 includes a blue dichroic mirror B in the first pixel PA1 and a red dichroic mirror R in the second pixel PA2. And a green dichroic mirror G in the third pixel PA3.

In this configuration, in the first pixel PA1, the blue dichroic mirror B of the first color filter layer 242 is emitted from the lamp 310 shown in FIG. 1 to transmit the first substrate 211. The blue light (LB) component of one white light is reflected. Red and green light (LR, LG) components of the white light component pass through the blue dichroic mirror (B).

In the same principle, in the second pixel PA2, the red light LR component among the white light is reflected by the red dichroic mirror R of the first color filter layer 242, and the green and blue light LG and LB are reflected. ) Component passes through the red dichroic mirror (R).

Similarly, in the third pixel PA3, the green light LG component of the white light is reflected by the green dichroic mirror G of the first color filter layer 242, and the red and blue light (LR, LB) components are reflected. Is transmitted through the green dichroic mirror (G).

The second color filter layer 243 is formed on the base substrate 240 at substantially the same position as the first color filter layer 242. That is, the second color filter layer 243 may be directly stacked on the first color filter layer 242, or may be formed at a position facing the first color filter layer 241 with the base substrate 240 therebetween. have.

Also, when the first color filter layer 241 and the second color filter layer 242 are formed with the base substrate 240 interposed therebetween, that is, the first color filter layer 241 and the first color filter layer 241 and the second color filter layer 242 are formed on both surfaces of the base substrate 240, respectively. When the second color filter layer 242 is formed, the first light blocking layer 241a and the second light blocking layer 241b may be formed on both surfaces of the base substrate 240, respectively.

The second color filter layer 243 is formed by a dichroic mirror in a region where the light blocking layer 241 is not formed, and the second color filter layer 243 is formed of each pixel PA1, PA2, and PA3. Each color reflects a different color, and each pixel PA1, PA2, and PA3 reflects the first color filter layer 242 and a dichroic mirror that reflects different colors.

For example, when the first pixel PA1 is a pixel expressing red light, when the first color filter layer 242 included in the first pixel PA1 is configured as a blue dichroic mirror B, The second color filter layer 243 included in one pixel PA1 is configured of the green dichroic mirror G.

Here, the dichroic mirror included in the first color filter layer 242 and the second color filter layer 243 may be formed so as to selectively reflect only one of the remaining colors except for the color of one pixel, and the formation order thereof. Can be formed independently.

The reflection and transmission of light by the second color filter layer 243 will now be described.

Referring to FIG. 4, the first color filter layer 242 includes a blue dichroic mirror B in the first pixel PA1 and a red dichroic mirror R in the second pixel PA2. And a green dichroic mirror G in the third pixel PA3. In addition, in order for the first pixel PA1 to express red light LR, the second pixel PA2 to green light LG, and the third pixel PA3 to express blue light LB, The second color filter layer 243 is composed of the green dichroic mirror G in the first pixel PA1, and is composed of the blue dichroic mirror B in the second pixel PA2, and the third pixel ( In the PA3), a red dichroic mirror R is formed.

In such a configuration, in the first pixel PA1, the green light LG of the red and green light LR and LG passing through the first color filter layer 242 is the green dichroic of the second color filter layer 243. Reflected by the mirror G, only the red light LR passes through the green dichroic mirror G. Accordingly, the first pixel PA1 may express red light LR.

In the same principle, in the second pixel PA2, the blue light LB of the green and blue light LGs and LBs passing through the first color filter layer 242 is the blue dichroic mirror of the second color filter layer 243. Reflected by (B), only the green light LG transmits the blue dichroic mirror B. FIG. Accordingly, the second pixel PA2 may express green light LG.

Similarly, in the third pixel PA3, the red light LR of the red and blue lights LR and LB transmitted through the first color filter layer 242 is the red dichroic mirror R of the second color filter layer 243. ), And only the blue light (LB) is transmitted through the red dichroic mirror (R). Accordingly, the third pixel PA3 may express blue light LB.

When the light transmission of the second substrate 212 is arranged by taking the first pixel PA1 as an example, when the first pixel PA1 is a pixel expressing the red light LR, the first pixel PA1 may be formed. The first color filter layer 242 is composed of a blue dichroic mirror B, and the second color filter layer 243 of the first pixel PA2 is composed of a green dichroic mirror G.

On the contrary, the first color filter layer 242 of the first pixel PA1 may be composed of a green dichroic mirror G, and the second color filter layer 243 of the first pixel PA2 is a blue dichroic. It can be configured as a mirror (B) has been described above.

Among the white light components incident on the first pixel PA1, the blue light LB is reflected by the first color filter layer 242 and filtered from the white light, and the green light LG of the white light components is the second color filter layer ( Reflected at 243 and filtered at white light. As a result, only the red light LR is transmitted through the second substrate 212 so that the red light LR is expressed.

In the same principle, the green and blue light LG and LB are emitted from the second and third pixels PA2 and PA3, respectively, so that the display panel 210 displays a predetermined image.

Referring to FIG. 3 again, the second substrate 212 of the display panel 210 according to the exemplary embodiment of the present invention further includes a cell gap holding member 245, a planarization layer 246, and a common electrode layer 247. do.

The cell gap holding member 245 is formed to keep the first substrate 211 and the second substrate 212 at a constant distance from each other. In order not to affect the light transmittance, the cell gap retaining member 245 is preferably formed in the region of the first light shielding layer 241, and is formed at an uniform density throughout the display panel 240. In one example, the cell gap retaining member 245 may be formed of a column spacer or a ball spacer.

The planarization layer 246 is formed of an organic insulating layer formed on the first color filter layer 242 to planarize the second substrate 212. In addition, the flattening film 246 may be formed on the stacked structure when the first color filter layer 242 and the second color filter layer 243 are stacked on the same surface of the base substrate 243.

The common electrode layer 247 is made of indium tin oxide (ITO), indium zinc oxide (IZO), or the like, which is a transparent conductive material. A common voltage is applied to the common electrode layer 248 to control the light transmittance by changing the molecular arrangement of the liquid crystal layer by the potential difference of the pixel voltage applied to the pixel electrode PE.

Although not shown in the drawings, the display panel 210 of the present invention extracts light that vibrates in a specific direction by transmitting only light having the same vibration direction among the light emitted from the lamp 310 shown in FIG. 1. It may further include a polarizing film.

The polarizing film may be attached to the first substrate 211 of the display panel 210 to attach the first polarizing film and the second substrate 212 to polarize the light emitted from the lamp 310, and then may be attached to the display panel 210. And a second polarizing film that polarizes the emitted light, and a third polarizing film that is formed between the first substrate 211 and the second substrate 212 to polarize the light incident inside the display panel 210. have.

According to the present invention as described above, it is possible to improve the light transmittance of the color filter substrate by forming a color filter layer using a dichroic mirror that can selectively reflect and transmit light in place of the photosensitive polymer organic material on the color filter substrate. have.

In addition, the light transmittance of the color filter substrate may be improved to improve luminance characteristics of the display panel and to improve display quality of the display panel.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (5)

A display panel in which a plurality of pixels are formed and displays an image using white light in which red, green, and blue light are mixed in color. A first substrate on which signal wires are provided for providing an image signal to each pixel; And A second substrate opposed to the first substrate to receive a liquid crystal layer; The second substrate is A base substrate; A first color filter layer formed on the base substrate and blocking light transmission of one color other than a color expressed in each pixel among the white light components; And And a second color filter layer formed on the base substrate, the second color filter layer blocking light transmission other than the color expressed in each pixel among the white light components and the color blocked in the first color filter layer. The display panel of claim 1, wherein the first color filter layer is formed on a first surface of the base substrate, and the second color filter layer is formed on a second surface that is a rear surface of the first surface. The display panel of claim 1, wherein the first and second color filter layers are formed on the same surface of the base substrate. The display panel of claim 1, wherein each of the color filter layers is formed of dichroic mirrors that block light transmission of different colors. The method of claim 1, wherein the second substrate is A light blocking layer partitioning each pixel; And And a common electrode layer providing a common voltage to each of the pixels.

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