KR100807583B1 - Liquid crystal display device and its fabrication method - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a manufacturing method capable of improving light efficiency. The present invention provides a liquid crystal display in which a liquid crystal is formed between a glass substrate and a lower substrate on which a thin film transistor and various wirings are formed, and an upper substrate on which a color filter and a black matrix are formed. An optical fiber is formed inside the glass substrate of the lower substrate on which the transistor is formed, and then a thin film transistor and various wirings are formed on the glass substrate on which the optical fiber is formed.

Description

Liquid crystal display and its manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND ITS FABRICATION METHOD}

1 is a view schematically illustrating a color filter substrate and a thin film transistor substrate constituting a liquid crystal display.

2 is a view showing a state in which light is transmitted from a backlight with respect to a glass substrate on which a metal line of a conventional thin film transistor is formed.

3A to 3E illustrate a method of manufacturing a thin film transistor.

4 is a detailed view of the lower substrate constituting the liquid crystal display of the present invention.

Figure 5a is a detailed view showing an optical fiber formed in the glass substrate according to the present invention.

FIG. 5B is a view illustrating a metal line of the thin film transistor formed on the resultant of FIG. 5A.

FIG. 6 is an enlarged detail view of an area indicated by a dotted line in FIG. 5B.

** Explanation of symbols for main parts of drawings **

10: glass substrate 11: color filter                 

12: black matrix 13: common electrode

14: alignment layer 15: gate electrode

16: active layer 17: gate insulating film

18: source electrode 19: drain electrode

20: protective film 21: pixel electrode

22: metal line (thin film transistor) 31: optical fiber

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a manufacturing method for maximizing light efficiency.

Recently, flat panel display devices have been actively developed in place of CRT displays, and among them, liquid crystal display devices have been particularly attracting attention due to advantages such as light weight, thinness, and low power consumption.

For example, an active matrix liquid crystal display in which switching elements are disposed in each display pixel is an electro-optical device using anisotropy of liquid crystal materials, and includes a lower substrate on which thin film transistors and various wirings are formed. A liquid crystal material is formed between the color filter and the upper substrate on which the black matrix is formed, and a driving circuit having a circuit for driving the thin film transistor and the wiring is attached to the edge of the lower substrate. In addition, a back light is mounted on the bottom or side of the substrate. The light from the backlight passes through the liquid crystal material through the transparent electrode of the lower substrate, and the transmitted light reaches the color filter of the upper substrate to realize an image. At this time, the transmittance of light in the liquid crystal material is controlled by the driving circuit, and a black matrix is formed at the pixel boundary to absorb light by external light rays and to improve contrast.

 The structure and function of the lower substrate and the upper substrate constituting the liquid crystal display according to the related art will be described with reference to FIG. 1 as follows.

1 is a view schematically illustrating a color filter substrate and a thin film transistor substrate constituting a liquid crystal display.
As shown in FIG. 1, the upper substrate includes a color filter 11 of a resin film containing three basic colors of dyes or pigments of red, green, and blue on the glass substrate 10, and the color filter 11. An overcoat film (not shown) for flattening the color filter 11 or to improve adhesion to the common electrode ITO, for the black matrix 12 of the light blocking film formed between the pixels of A common electrode 13 made of ITO, which is a transparent electrical conductor formed to apply a voltage to a liquid crystal cell, and an alignment layer 14 formed for alignment of liquid crystal molecules.

Here, the lower substrate is formed on the glass substrate 10 and the gate electrode 15 to which the scan signal is applied, the active layer 16 provided to transmit the data signal in response to the scan signal, and the active layer 16. And a gate insulating film 17 that electrically isolates the gate electrode 15, a source electrode 18 formed on the active layer 16 to apply a data signal, and a drain to apply the data signal to the pixel electrode. The protective film 20 which protects the electrode 19, the source electrode 18, and the drain electrode 19 is comprised. The drain electrode 19 is connected to the pixel electrode 21 through a contact hole, and the pixel electrode 21 is formed of a transparent electrode made of ITO to transmit a light beam. And, the alignment film 14 formed for the alignment of the liquid crystal molecules is configured.

The active layer 16 is composed of a semiconductor layer 16a formed by depositing amorphous silicon (a-Si) and an ohmic contact layer 16b doped with n + on both sides of the semiconductor layer 16a. It is.

When a scan signal having a high level is applied to the gate electrode 15, a channel through which electrons may move is formed in the semiconductor layer 16a, so that the data signal of the source electrode 18 is converted into a semiconductor layer ( It is delivered to the drain electrode 19 via 16a. On the other hand, when a scan signal having a low level is applied to the gate electrode 15, the channel formed in the semiconductor layer 16a is blocked, so that the transmission of the data signal to the drain electrode 19 is stopped.

The metal film of the transparent electrode ITO, the gate electrode, and the source / drain electrodes is deposited by a sputtering method.

The gate electrode 15 is made of aluminum (Al) or aluminum alloy or copper (Cu), and the source / drain electrodes are chromium (Cr) or molybdenum (Mo) or aluminum (Al) or aluminum alloy. Or copper (Cu).

Metals used as materials for the gate electrode and the source / drain electrodes do not pass light unlike the ITO of the transparent electrode.

As described above, the metal lines of the thin film transistor formed on the glass substrate block the light incident from the backlight, thereby reducing the light transmission efficiency of the liquid crystal panel.
2 is a view showing a state in which light is transmitted from a backlight with respect to a glass substrate on which a metal line of a conventional thin film transistor is formed.
In the conventional liquid crystal display, as shown in FIG. 2, light incident from the backlight and passed through the glass substrate does not pass through the portion where the metal lines 22 of the thin film transistor are formed on the glass substrate 10. In other words, light may pass through only the metal lines, thereby reducing the light efficiency of the liquid crystal display.
Meanwhile, a method of manufacturing a thin film transistor formed on a glass substrate will be described in detail with reference to the drawings of FIGS. 3A to 3E.
3A to 3E illustrate a method of manufacturing a thin film transistor.
First, as shown in FIG. 3A, a metal material is sputtered onto the glass substrate 10, and patterned by photolithography using a photoresist to form the gate electrode 15 of the thin film transistor. ).
As the material of the gate electrode, aluminum (Al), aluminum alloy, copper (Cu), or the like may be used.
As shown in FIG. 3B, an insulating material is entirely deposited on the glass substrate 10 on which the gate electrode 15 is formed to form a gate insulating film 17. As the material of the gate insulating film 17, an inorganic material such as SiNx is mainly used. On the gate insulating layer 17, a semiconductor layer 16a made of amorphous silicon (Si) and an ohmic contact layer 16b made of n + amorphous silicon doped with phosphorus (P) are successively deposited, and then patterned to form a thin film transistor. The active layer 16 is formed.
As shown in FIG. 3C, a metal material is entirely deposited on the ohmic contact layer 16b and the gate insulating layer 17 and then patterned. The patterned metal material layer becomes the source electrode 18 and the drain electrode 19 of the thin film transistor. Thereafter, the ohmic contact layer 16b exposed on the source electrode 18 and the drain electrode 19 is removed by an etching operation.
As the material of the source / drain electrode, chromium (Cr), molybdenum (Mo), aluminum (Al), aluminum alloy, or copper (Cu) may be used.
As shown in FIG. 3D, a passivation layer 20 is entirely formed on the gate insulating layer 17 including the exposed semiconductor layer 16a and the source and drain electrodes 18 and 19. do. Then, a contact hole is formed in the protective film portion on the drain electrode 19 of the thin film transistor by an etching operation using a mask pattern.
Inorganic materials such as SiNx are mainly used as the material of the protective film, but recently, organic materials such as BCB (Benzocyclobutene), SOG (Spin on Glass), and acrylic (Acryl) having a low dielectric constant for high-opening structure as in the present invention Substances are used.
Subsequently, as illustrated in FIG. 3E, the ITO material is deposited on the protective film 20 by sputtering and then patterned to form the pixel electrode 21. The pixel electrode 21 is connected to the drain electrode 19 of the thin film transistor through a contact hole.
As described above, the lower substrate of the liquid crystal display device having the above structure does not completely pass through the glass substrate which is incident from the backlight of the liquid crystal display device and passes through the metal lines of the thin film transistors formed on the glass substrate. The metal lines are blocked due to the low light efficiency.

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Accordingly, the present invention has been made to solve the above problems according to the prior art, a liquid crystal display for transmitting all the light without loss of light due to the metal lines forming the thin film transistor formed on the glass substrate It is an object to provide an apparatus and a method of manufacturing the same.
In addition, an object of the present invention is to provide a liquid crystal display device that can maximize the light transmittance incident from the backlight.

Another object of the present invention is to provide a method of manufacturing a liquid crystal display device capable of maximizing light transmittance incident from a backlight.

Other objects and features of the present invention will be described in detail in the configuration and claims of the following invention.

The liquid crystal display device according to the present invention for achieving the above object is a liquid crystal in which a liquid crystal is formed between a glass substrate and a lower substrate on which a thin film transistor and various wirings are formed, and an upper substrate on which a color filter and a black matrix are formed. In the display device, the optical fiber is formed inside the glass substrate of the lower substrate on which the thin film transistor is formed, and then the thin film transistor and various wirings are formed on the glass substrate on which the optical fiber is formed.

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The optical fiber is formed in all portions except the line widths of the metal wires formed on the glass substrate as the optical fiber is directed toward the upper portion of the glass substrate. That is, the optical fiber formed inside the glass substrate has a trapezoidal shape in which the line width is narrowed upward.

In addition, a method of manufacturing a liquid crystal display device according to the present invention includes a liquid crystal display in which a liquid crystal is formed between a glass substrate and a lower substrate on which a thin film transistor and various wirings are formed, and an upper substrate on which a color filter and a black matrix are formed. An apparatus comprising: adding a fiber optic material together when making a glass substrate used as a substrate of a thin film transistor in manufacturing a lower substrate including a thin film transistor, and then forming a thin film transistor on the glass substrate to which the optical fiber is added. .

Hereinafter, a structure and a manufacturing method of a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.

4 illustrates a lower substrate constituting the liquid crystal display according to the present invention.
5A is a detailed view illustrating an optical fiber formed in a glass substrate according to the present invention, and FIG. 5B is a view illustrating a metal line of a thin film transistor formed on the resultant of FIG. 5A.
As shown in FIG. 4, in the liquid crystal display according to the present invention, the optical fiber 31 is formed in the glass substrate 10 with the metal lines 22 of the thin film transistors formed on the glass substrate interposed therebetween. The optical fiber 31 formed inside the glass substrate 10 collects and transmits light (arrows in the drawing) incident from the back of the lower substrate, that is, from the light source of the backlight.

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In addition, as shown in FIG. 5A, when the glass substrate is manufactured, an optical fiber material is added to the remaining portion of the glass substrate 10 except for a position where metal wirings of the thin film transistor to be subsequently formed on the glass substrate are formed. 31) is formed.

Since the light incident from the back light can pass through the lower substrate only through the optical fiber, the area of the optical fiber formed under the glass substrate is made as wide as possible to transmit all the light incident from the rear surface of the lower substrate. That is, the width of the optical fiber decreases toward the upper portion of the substrate, so that the shape of the optical fiber seen in the cross section is trapezoidal in shape where the lower side is longer than the upper side. In addition, a plastic substrate may be used instead of the glass substrate.

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As shown in FIG. 5B, metal lines of the thin film transistor are formed on the glass substrate other than the optical fiber.

Thereafter, the method of manufacturing the formed thin film transistor is the same as the conventional thin film transistor manufacturing method.

The glass substrate on which the metal line of the thin film transistor is formed on the glass substrate decreases in width toward the bottom of the glass substrate.

FIG. 6 illustrates a path of light passing through an optical fiber by enlarging a portion indicated by a dotted line in FIG. 5B.

As shown in FIG. 6, the optical fiber collects light without a loss of light while the light passes, and serves as an optical path. That is, light that is blocked by the metal lines of the thin film transistor on the glass substrate is transmitted through the optical fiber, thereby increasing the efficiency of the area that passes the light relatively.

As described above, according to the liquid crystal display device and the manufacturing method thereof, the metal of the thin film transistor formed on the glass substrate by collecting the light by forming an optical fiber inside the glass substrate of the lower substrate including the thin film transistor. The light transmittance can be improved by preventing the light incident from the backlight from being blocked by the line.

Claims (7)

A first substrate; An optical fiber formed in the first substrate; A thin film transistor and a wiring formed on the first substrate; A color filter layer formed on the second substrate; And And a liquid crystal layer formed between the first substrate and the second substrate. The liquid crystal display of claim 1, wherein the line width of the optical fiber has a smaller line width toward the upper portion of the first substrate. The liquid crystal display device according to claim 1, wherein the optical fiber is formed at a portion other than a wiring formed on the first substrate. The liquid crystal display of claim 1, wherein the substrate is a glass substrate or a plastic substrate. Providing a first substrate and a second substrate; Forming an optical fiber in the first substrate; Forming a thin film transistor and a wiring on the first substrate on which the optical fiber is formed; Forming a color filter layer on the second substrate; And And forming a liquid crystal layer between the first substrate and the second substrate. The method of claim 5, wherein the optical fiber is formed such that a line width decreases toward an upper portion of the first substrate. The method of claim 5, wherein the optical fiber is formed at a portion other than a wiring formed on the first substrate.

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