KR20070107287A - Liquid crystal display device - Google Patents

Abstract

A liquid crystal display device is provided to improve the brightness by realizing full colors by using CCM layers, which have high light efficiency and convert short-wavelength lights into red, green, and blue colors, the three primary colors, instead of color filter layers. A liquid crystal display device has a first substrate(101) and a second substrate(102) oppositely bonded with each other, and a light source(600) arranged under the first substrate. A thin film transistor(TFT) and a pixel electrode(117) are formed at each sub-pixel defined by gate lines and data lines vertically crossing on the first substrate. CCM(Color Change Modulation) layers(132a,132b,132c) are formed on the second substrate, corresponding to each sub-pixel.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY DEVICE}

1 is a cross-sectional view of a liquid crystal display device according to the prior art.

2 is a cross-sectional view of a liquid crystal display device according to the present invention.

<Description of Symbols for Main Parts of Drawings>

100 liquid crystal layer 101 first substrate

102 second substrate 103 polarizing plate

104: alignment layer 117: pixel electrode

132a, 132b, and 132c: first, second and third CCM layers

134: black matrix 135: overcoat layer

137: common electrode 500: drive IC

600: light source 601: optical sheet

700: liquid crystal panel

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device using a CCM (color changing media) layer as the color means.

Recently, researches on flat panel displays have been actively conducted, and among them, liquid crystal display devices (LCDs), field emission display devices (FEDs), electro-luminescence display devices (ELDs), and PDPs (PDPs) Plasma Display Panels).

Among them, the liquid crystal display device, which is one of the flat panel display devices, which has been attracting attention in recent years, is an element that changes the optical anisotropy by applying an electric field to liquid crystals having liquid properties and optical properties of crystals. In addition to its lap top computer and pocket computer, its use is rapidly expanding for use in vehicle loading and color TV images.

The liquid crystal display device is disposed such that a color filter layer array substrate as an upper substrate and a thin film transistor (TFT) array substrate as a lower substrate are opposed to each other, and a liquid crystal having dielectric anisotropy is formed therebetween. Has a structure.

However, since the liquid crystal display itself is non-luminescent, a separate external light source for irradiating light is required. In particular, in the case of a transmissive liquid crystal display device, a separate dimming device that emits light and guides the back of the LCD panel is necessary.

The light provided from the backlight is controlled by a liquid crystal panel composed of a plurality of sub-pixels arranged in a matrix and a plurality of control switches for switching a video signal to be supplied to each of these sub-pixels. This displays the desired image on the screen.

Hereinafter, a liquid crystal display device according to the related art will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a liquid crystal display device according to the prior art.

As shown in FIG. 1, a typical liquid crystal display device includes a liquid crystal panel in which a color filter layer array substrate 1 and a thin film transistor array substrate 2 are opposed to each other with a liquid crystal layer 5 interposed therebetween, and the liquid crystal. A polarizing plate 6 attached to the upper and lower outer peripheral surfaces of the panel to transmit only light in a predetermined direction, and a back light for providing light to the liquid crystal panel by providing a gap between the liquid crystal panel 8 and the gap between the liquid crystal panel 8 and the front surface thereof. 9), a case surrounding the outside surface of the backlight to support the liquid crystal panel and the backlight, and a bezel portion of a stainless steel material attached to the outside of the case and surrounding an edge except for an effective area where an image is displayed. .

As described above, in the liquid crystal display device (particularly, in the case of a transmissive or semi-transmissive liquid crystal display device), a backlight for providing light is configured as an essential component.

At this time, a plurality of gate lines and data lines arranged vertically on the inner surface of the thin film transistor array substrate 2 to define sub-pixels, and at the intersections of the gate lines and data lines, the voltage is turned on. A thin film transistor (TFT) for controlling on or turn-off and a pixel electrode connected to the thin film transistor (TFT) to apply a voltage to the liquid crystal layer are provided.

In addition, red, green, and blue color filter layers 10 arranged in a predetermined order on the inner surface of the color filter layer array substrate 1 and R, G, and B cells A black matrix, which serves as a division between and light blocking, and a common electrode for applying a voltage to the liquid crystal cell are provided.

As such, in the liquid crystal display device, color filter layers 10 having R, G, and B colors are formed on the color filter layer array substrate 1, so that white light emitted from the backlight 9 passes through the color filter layers of each color. Implement various colors. In addition, the amount of light generated in the backlight is adjusted according to the arrangement state of the liquid crystal layer and the position of the polarization axis of the polarizer to realize gray scale.

In this case, the color filter layer 18 is formed by separately patterning a color resist (color resist) containing pigments for implementing R, G, and B colors for each sub-pixel. In order to form the color filter layer, complex processes such as a dyeing method, a pigment dispersion method, a coating method, an electrodeposition method, and an inkjet method are performed.

However, the conventional liquid crystal display device as described above has the following problems.

Conventional color filter layers are formed by coating and patterning color resists containing pigments of R, G, and B colors, and have a problem in that light transmittance is lowered due to a high rate of absorption of white light incident from the backlight by the color filter layers. .

That is, the white light passing through the R color filter layer passes only the R color and absorbs the remaining colors, and the white light passing through the G color filter layer passes only the G color and absorbs the remaining colors, and the white light passing through the B color filter layer is the B color. Only pass and absorb the rest of the colors. As such, the light transmittance is greatly reduced because all the light except for the constant wavelength color is absorbed.

Therefore, in order to solve the above problems, the present invention implements a full color by applying a CCM (color changing media) layer which converts light of relatively high wavelength and converts short wavelength light into red, green, and blue primary colors. An object of the present invention is to provide a liquid crystal display device, and to improve the luminance of the device by applying a CCM layer having excellent light efficiency without using a color filter layer having high light absorption as a color means.

In the liquid crystal display device according to the present invention for achieving the above object, in the liquid crystal display device in which the first and second substrates are opposed to each other with the liquid crystal layer interposed therebetween, and a light source is disposed below the first substrate. A thin film transistor and a pixel electrode formed in each sub-pixel defined by a gate line and a data line vertically intersecting on one substrate, and a color change modulation (CCM) layer formed to correspond to each sub-pixel on the second substrate. Characterized in that comprises a.

That is, the present invention is characterized in that the CCM layer is used as a color means without using a conventional color filter layer. The color filter layer absorbs a specific wavelength and passes only the wavelength of a desired color, so that the light transmittance is low, whereas the CCM layer is used. Since silver is not absorbing light but converting it, the light transmittance is higher than that of the color filter layer. Therefore, the brightness of the device can be improved by using the CCM layer.

Even in the case of applying the CCM layer, red, green, and blue primary colors are used to realize full color, and blue light provided by a light source such as a light emitting diode is used. The red, green, and blue CCM layers convert the light into red, green, and blue light to display an image.

The CCM layer is formed such that the first, second, and third CCM layers emitting red, green, and blue colors correspond to each sub-pixel, and a black matrix is further provided at the sub-pixel boundary. On the front surface including the second and third CCM layers, an overcoat layer is further provided to compensate for the step difference.

Hereinafter, the liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view of a liquid crystal display device according to the present invention.

As shown in FIG. 2, the liquid crystal display according to the present invention includes a first substrate 101 having sub-pixels arranged on a matrix and a second substrate 102 having a CCM layer 132 for converting colors. ) Is attached to the liquid crystal panel 700 facing each other with the liquid crystal layer 100 interposed therebetween, a polarizing plate 103 attached to an outer surface of the liquid crystal panel 700 to polarize natural light, and a voltage applied to each of the pixels. A driver IC (Intergrated Circuit) 500 for applying a signal for driving a liquid crystal, a light source 600 attached to a lower portion of the liquid crystal panel 700 to uniformly irradiate an information display surface, and the liquid crystal panel And a plurality of optical sheets 601 inserted between the light source and the light source to enhance the light scattering effect. The light emitted from the light source is color-converted by the CCM layer to realize a full color image.

The drive IC 500 is attached to a tape carrier 501 to be connected to a printed circuit board (PCB). In recent years, the drive IC 500 directly mounts the drive IC on a first substrate. On Glass) is also applied a lot.

Specifically, on the first substrate 101, a plurality of gate wirings and data wirings defining a plurality of sub-pixels at vertical crossings, a thin film transistor (TFT) formed at an intersection of the two wirings, and the thin film transistors. The pixel electrode 117 is formed in contact with the drain electrode of the pixel. Typically, the thin film transistor is composed of a laminated film of a gate electrode, a gate insulating film, a semiconductor layer, and a source / drain electrode.

First, second, and third CCM layers 132a, 132b, and 132c are sequentially arranged on the second substrate 102 in sub-pixel units, and the first, second, and third CCM layers ( Black matrices 134 are formed at the color boundaries of 132a, 132b, and 132c to prevent color interference and light leakage. An overcoat layer 135 is formed on the front surface including the first, second, and third CCM layers 132a, 132b, and 132c to prevent material movement between the CCM layer and the liquid crystal and to planarize the surface on which the CCM layer is formed. The common electrode 137 made of a conductive material having a permeability is formed on the overcoat layer 135.

The first and second substrates 101 and 102 are formed on the edge of the liquid crystal panel and completely bonded to the sealing agent 800, which serves as an adhesive. An electric field is formed between the pixel electrode of the first substrate and the common electrode of the second substrate. Is formed to drive the liquid crystal layer in a constant direction. For reference, an alignment layer 104 is further provided on the inner side surfaces of the first and second substrates to determine the initial alignment direction of the liquid crystal layer.

In the liquid crystal display device, light provided from the light source 600 passes through the CCM layer 132 of the liquid crystal panel 700 to realize full coloration. The light source has the highest energy among red, green, and blue colors. It is preferable that the branch includes a blue color light emitting material. This is because conversion and emission of light with a relatively long wavelength is possible only by using light having a high energy (short wavelength).

As the light source, a laser diode (LD), an organic light emitting diode (OLED), or the like may be used, and any one of a surface light source, a line light source, and a point light source may be used. However, in the case of using a linear light source or a point light source, a plurality of optical sheets will be required in order to uniformize the light irradiation distribution.

As described above, the present invention is characterized by using a CCM layer as a color means. When the blue light provided by the light source is absorbed by the red, green, and blue CCM layers, the CCM layer is converted into red, green, and blue light. do.

The CCM layer uses three primary colors of red, green, and blue to realize full color, and the materials for converting and emitting red, green, and blue colors are different. It is formed by separately patterning each sub-pixel region.

There may be various methods of forming the CCM layer, which may be formed by coating the CCM material by a printing method or a coating method and then patterning it by photo-lithography, or by forming a shadow mask. It can also be formed by masking and printing the desired CCM material on the desired sub-pixels.

In this way, the red, green, and blue CCM layers are formed in order to have a uniform array pattern. A first CCM layer 132a converting and emitting red is formed in the red sub-pixel, and green is formed in the green sub-pixel. A second CCM layer 132b that converts and emits light is formed, and a third CCM layer 132c that converts and emits blue is formed in the blue sub-pixel.

In this case, the first and second CCM layers 132a and 132b are formed of a material that emits red light and green light, respectively, and the third CCM layer 132c is adjacent to the first first agent without a specific color conversion ability. 2 It plays a role of matching step with CCM layer.

On the other hand, the above embodiment is only a description of a preferred embodiment of the present invention, the scope of application of the present invention is not limited to such, the present invention can be appropriately changed within the scope of the same idea.

For example, the shape and structure of each component specifically shown in the embodiment of the present invention can be modified and implemented. In the above embodiment, the common electrode is limited to the second substrate. The electric field for driving the liquid crystal layer may be formed on the first substrate so as to be parallel to the pixel electrode instead of the second substrate.

In addition, in the above embodiment, the color means is constituted by a single CCM layer, but in some cases, the color means may be constituted by a double layer of the color filter layer and the CCM. The color filter layer is used as a color means of a conventional liquid crystal display device, and may be formed of a resist including R, G, and B pigments, and may be provided above or below the CCM layer.

The liquid crystal display of the present invention as described above has the following effects.

First, the present invention realizes full-color by applying a CCM layer that converts short wavelength light into red, green, and blue primary colors without using a conventional color filter layer as a color means. The filter layer has a transmittance of 70% while the CCM layer has a transmittance of 80-90%.

Therefore, the brightness of the device can be improved by using the CCM layer, and the image quality is upgraded.

Second, in case of CCM layer expressing the same color as the color of light source, it plays a role of matching the step with neighboring CCM layer without any specific color conversion ability. The transmittance becomes high, and eventually the luminance of the device can be further improved.

Claims (8)

In the liquid crystal display device wherein the first and second substrates are opposed to each other with the liquid crystal layer interposed therebetween, and a light source is disposed below the first substrate. A thin film transistor and a pixel electrode formed in each sub-pixel defined by gate lines and data lines vertically intersecting on the first substrate; And a color change modulation (CCM) layer formed to correspond to each sub-pixel on the second substrate. The method of claim 1, The light source is a liquid crystal display device, characterized in that the light emitting diode (LED). The method of claim 1, And the CCM layer comprises first, second, and third CCM layers emitting red, green, and blue light. The method of claim 1, The light source provides blue light, And the CCM layer converts the blue light of the light source into red, green, and blue primary colors. The method of claim 1, And a black matrix further formed at a sub-pixel boundary on the second substrate. The method of claim 1, And a common electrode facing the pixel electrode, wherein the common electrode is formed on the first substrate or the second substrate. The method of claim 1, And a color filter layer on or above the CCM layer. The method of claim 1, Liquid crystal display device further comprises an overcoat layer formed on the entire surface including the CCM layer.

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