JPH095783A - Liquid crystal display element - Google Patents

Abstract

PURPOSE: To lessen pollution and to prevent the degradation in the display grade and product yield occurring in the residues of a resist by forming a black matrix of multilayered films consisting of MoO films and Mo films. CONSTITUTION: The black matrix BM of this liquid crystal display element 30 of an active type or passive type obtd. by enclosing liquid crystals 3 between two sheets of glass substrates 1 and 2 facing each other and forming the black matrix BM on the inside surface of the one glass substrate 2 is obtd. by forming the MoO films by sputtering Mo as a target in an atmosphere of a gaseous mixture composed of an inert gas and oxygen on the inside surface of the glass substrate 2. Then, the Mo films is formed by sputtering of Mo as a target in an atmosphere of an inert gas. TFT arrays 4 are formed on the inside surface of another glass substrate 1 and light shields 6 for shielding the light on transistors are formed of the Mo. The possibility of giving rise to pollution in the case of discarding is eliminated by using the non-polluting multilayered Mo/MoO films in such a manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention relates to a liquid crystal display device (hereinafter referred to as L
The black matrix (referred to as CD), the light shield for the TFT, and the like, in which a pollutant such as Cr is deleted.

[0002]

2. Description of the Related Art An active type LCD 3 with color display
As shown in FIG. 5, 0 is two glass substrates 1 facing each other.
The liquid crystal 3 is sealed between the two, and the TF is formed on the inner surface of the glass substrate 1.
The T array 4 is formed. TF from the glass substrate 1 side
A light shield 6 made of a Cr film is formed in order to shield the light hitting each TFT 5 of the T array 4 and improve the on / off ratio of the TFT.

In the TFT array 4, a source electrode 5s, a source bus 8, a drain electrode 5d, and a pixel electrode (also referred to as a display electrode) 9 are made of ITO on a SiO ₂ layer 7 formed on the glass substrate 1 over the entire surface. It A-S is formed on the SiO ₂ layer 7 over the source electrode 5s and the drain electrode 5d.
A semiconductor layer 5a such as i (amorphous silicon) is formed. Source bus 8, pixel electrode 9 and semiconductor layer 5
A gate insulating film 10 such as SiNx (silicon nitride) is formed on the entire surface a, and a gate electrode 5g and a gate bus (not shown) made of aluminum or the like are formed thereon.

On the other hand, a color filter 21 is formed on the inner surface of the glass substrate 2. The color filter 21 includes R, G,
B micro color filters FR, FG, and FB are formed in a matrix corresponding to each pixel, and a black film composed of a Cr film or a multilayer film of CrO and Cr whose reflectance is improved between these micro color filters. A matrix (also called a black stripe) BM is formed.
As is well known, the black matrix BM improves the visibility by improving the contrast and color purity by blocking light.

A common electrode 22 made of ITO is formed on the inner surface of the color filter 21, and the alignment film 2 is formed on the inner surface of the common electrode 22.
3 is formed. An alignment film 24 is similarly formed on the inner surface of the TFT array 4. Polarizing plates 25 and 26 are provided on the outer surfaces of the glass substrates 1 and 2, respectively.

[0006]

A Cr / CrO multilayer film and a Cr film are used for the black matrix BM and the light shield 6 of the conventional LCD, respectively. However, since Cr and CrO are pollutants and have a bad effect on the human body, they become a problem when the LCD is used up and is discarded. Liquid crystal display devices are expected to be used more and more in homes and businesses in the future, which may cause a serious social problem.

When the color filter 21 is formed on the glass substrate 2 on which the black matrix BM is formed,
After developing the R, G, and B resists, the unnecessary resist is removed by brushing in a cleaning process. However, when the black matrix BM is Cr-based, the R, G, and B resists are likely to remain on the black matrix BM as a residue, and the residue sometimes adheres to the rubbing cloth like dust or dust when the alignment film 23 is rubbed. At the same time, the dust and dust may remain in the liquid crystal cell, deteriorating the display quality and deteriorating the product yield.

An object of the present invention is to solve these conventional problems so as to prevent the use of pollutants such as Cr-based materials in the black matrix and the light shield, and to prevent R, G, B when forming color filters. It is intended to prevent the deterioration of display quality and product yield due to the residue of the resist.

[0009]

[Means for Solving the Problems]

(1) The invention of claim 1 is a color or monochrome display in which a liquid crystal is sealed between two glass substrates facing each other, and a black matrix is formed on the inner surface of one of the glass substrates. In the LCD of
In particular, the black matrix is a non-polluting MoO film and M
It is formed of a multi-layer film including an o film.

(2) According to the invention of claim 2, in the above (1), a TFT array is formed on the inner surface of the other glass substrate, and a light shield for shielding each transistor is formed of non-polluting Mo. There is something. (3) The invention according to claim 3 is an active-type L for monochrome display.
In the CD, in particular, the light shield that shields each transistor of the TFT array is formed of a multi-layer film including a MoO film and a Mo film.

(4) According to a fourth aspect of the present invention, in a monochrome display active LCD, in particular, the source electrode and source bus of the TFT array are formed of a multilayer film composed of a MoO film, a Mo film and an ITO film. There is something.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is shown in FIGS. 1 to 3 by attaching the same reference numerals to the portions corresponding to those in FIG. In the present invention, as shown in FIGS. 1 and 2, the black matrix BM is composed of a multilayer film including a MoO film and a Mo film which are non-polluting substances (claim 1).

Conventionally, a Cr film or a Cr / CrO multilayer film has been used. The LCD can be applied to both color display (FIG. 1) and monochrome display (FIG. 2). Further, it can be applied not only to the active type but also to the passive type. Further, as the write shield 6, a non-polluting Mo film, for example, is used instead of the conventional Cr film (claim 2).

The black matrix BM is a glass substrate 1.
On the inner surface of Mo to form a MoO film by sputtering in a mixed gas atmosphere of an inert gas and oxygen with Mo as a target, and then sputtering an MoO film on the MoO film in an atmosphere of an inert gas as a target. Form a film.
The reflectance can be lowered by disposing the MoO film on the side where the display screen is viewed and the Mo film on the back surface.

The reflectance of the Mo / MoO multilayer film can be controlled by the film thickness, refractive index, atmospheric gas pressure during sputtering, oxygen partial pressure, gas flow rate, sample substrate temperature and the like.
The bottom reflectance of the Mo / MoO multilayer film used in the present invention is as shown in FIG.
It is extremely small, 1-2%. The reflectivity of the conventional Cr film is 50
Since it is -60% and that of the improved Cr / CrO multilayer film is 1-5%, the present invention is considerably improved not only in pollution prevention but also in low reflectance.

The Mo / MoO multilayer film has optical and electrical properties similar to those of the Cr / CrO multilayer film except that it is non-polluting. For example, both have an optical density (OD) of about 4, an oxide film refractive index of 1.8 to 2.0, and a sheet resistance of 5 to 10
Ω. As an application of lowering the reflectance by the Mo / MoO multilayer film, it can be applied to the light shield 6, the source electrode 5s and the source bus 8 of the active type LCD in monochrome display (claims 3 and 4).

In FIG. 3, the light shield 6 is Mo / MoO.
It is formed of a multilayer film. Conventionally, there has been an example of forming a metal film of Mo, Al, Cr or the like on the ITO film in order to recommend the conductivity of the source bus. In this invention, ITO / Mo /
With the MoO multilayer film, the reflectance of the source electrode and the source bus can be further reduced in addition to the high conductivity. Thereby, the reflection from the source electrode 5s and the source bus 8 is almost eliminated, and the display quality can be further improved.

Conventionally, when a Cr-based black matrix is used for the black matrix BM, even if the R, G, B resists are washed when forming the R, G, B color filters, they remain on the black matrix as a residue, as already described. The rest, the residue dusts,
It became dust and remained in the cell, degrading the display quality and yield. However, in this invention, Mo / M is used instead of the Cr system.
It has been confirmed by trial manufacture and experiments that the use of the oO composite film does not generate the resist residue as described above and can prevent the deterioration of the display quality and the yield due to the residue.

[0019]

According to the present invention, as the black matrix BM and the light shield 6, the conventional pollutant Cr / CrO multilayer film and Cr are used.
Since a non-polluting Mo / MoO multilayer film or Mo film is used instead of the film, there is no fear of pollution due to the black matrix or the light shield when the LCD is discarded.

In the present invention, the black matrix BM
Since the Mo / MoO composite film is used as the above, no residue of R, G, and B resists is generated at the time of forming the R, G, and B color filters, and it is possible to prevent deterioration of display quality and yield due to this residue. . The Mo / MoO multilayer film is a conventional Cr film or Cr / CrO.
Since the reflectance is lower than that of the multilayer film, the visibility can be improved by using the black matrix or the light shield.

When a composite film of ITO / Mo / MoO is used as the source electrode 5s and the source bus 8 of the monochrome display LCD, almost no reflection occurs as compared with the conventional metal film of Cr or the like / ITO multilayer film. It can be eliminated and the visibility can be further improved.

[Brief description of drawings]

FIG. 1A is a sectional view showing an embodiment (active type in color display) of the invention of claim 1, and B is an enlarged sectional view of the TFT of A and its periphery.

2A is a sectional view showing another embodiment (active type in black and white display) of the invention of claim 1, and FIG. 2B is an enlarged sectional view of the TFT of A and its periphery.

FIG. 3A is a sectional view showing an embodiment of the invention of claims 3 and 4, and B is an enlarged sectional view of the TFT of A and its periphery.

FIG. 4 is a graph showing reflection spectral characteristics of a Mo / MoO multilayer film used in the present invention.

FIG. 5A is a conventional color display active LCD.
FIG. 2B is an enlarged sectional view of the TFT of A and its periphery.

Claims (4)

[Claims] 1. An active or passive liquid crystal display device for color or monochrome display in which liquid crystal is sealed between two glass substrates facing each other and a black matrix is formed on the inner surface of one of the glass substrates. A liquid crystal display device, wherein the black matrix is formed of a multi-layer film including a MoO film and a Mo film. 2. A liquid crystal display element according to claim 1, wherein a TFT array is formed on the inner surface of the other glass substrate, and a light shield for shielding each transistor is formed of Mo. 3. A monochrome display in which a liquid crystal is sealed between two glass substrates facing each other, a common electrode is formed on the inner surface of one of the glass substrates, and a TFT array is formed on the inner surface of the other glass substrate. 2. The liquid crystal display element according to the above item (1), wherein the light shield that shields each transistor of the TFT array is formed of a multilayer film including a MoO film and a Mo film. 4. A monochrome display in which a liquid crystal is sealed between two glass substrates facing each other, a common electrode is formed on the inner surface of one of the glass substrates, and a TFT array is formed on the inner surface of the other glass substrate. In the liquid crystal display element of, the source electrode and the source bus of the TFT array are Mo.
A liquid crystal display element comprising a multi-layered film including an O film, a Mo film and an ITO film.