JPH1172799A - Pixel driving element for liquid crystal display and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the degradation in image quality by the influence of the through-holes of pixel driving elements consisting of the active elements formed on a substrate, insulating layers having through-holes and pixel electrodes in the liquid crystal display of a reflection type active matrix type. SOLUTION: The plural active elements 3 are formed on the substrate 2 and the insulating layer 4 having the through-holes 5 is formed in the position corresponding to the active elements 3 on the active elements 3. The through- holes 5 are embedded with a conductive material 6 and the parts of the conductive materials 6 projecting from the front surface 4a of the insulating layer 4 are polished and are planarized so as to be made flush with the front surface 4a of the insulating layer 4. The pixel electrodes 7 are formed on the planarized surface 4a, by which the pixel driving element 1 having flat surfaces on the contact surfaces 7a of the pixel electrodes 4 with the liquid crystal layer is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflective active matrix type pixel driving device for a liquid crystal display and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a reflection type active matrix type liquid crystal display pixel driving element has a number of active elements corresponding to the number of pixels formed on a substrate, an insulating layer formed on the active elements, and an insulating layer formed on the active layer. A through hole is formed to communicate with a part of each active element, and a pixel electrode is formed on the insulating layer so as to be electrically connected to the active element via the through hole.

When a pixel electrode is formed on an insulating layer having a through hole by vapor deposition or the like, a uniform thickness is formed on the insulating layer including the through hole in the pixel electrode. The pixel electrode material is buried, and a concave portion corresponding to the through hole is formed on the upper surface of the pixel electrode in contact with the liquid crystal layer. This recess causes irregular reflection of light during operation of the liquid crystal display. In addition, the electric field lines are distorted, which adversely affects light modulation. These lead to deterioration of the image quality of the liquid crystal display. Therefore, it is desired that the operation of the liquid crystal display is not affected by such through holes.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is not affected by through holes formed in an insulating layer for electrical connection between an active element and a pixel electrode. It is an object of the present invention to provide a pixel driving element for a liquid crystal display for obtaining a reflection type active matrix type liquid crystal display and a method for producing the same.

[0005]

A pixel driving element for a liquid crystal display according to the present invention comprises an active element formed on a substrate and a through hole formed on the active element at a position corresponding to the active element. A reflective active matrix type liquid crystal display pixel drive element comprising an insulating layer having and a pixel electrode formed on the insulating layer and electrically connected to the active element through the through hole,
An upper surface of the pixel electrode in contact with a liquid crystal layer is flat.

According to a method of manufacturing a pixel driving element for a liquid crystal display of the present invention, an active element is formed on a substrate, and an insulating layer having a through hole at a position corresponding to the active element is formed on the active element. Forming a pixel electrode electrically connected to the active element through the through hole on the insulating layer, a method of producing a pixel drive element for a reflective active matrix type liquid crystal display, comprising: Before the formation, the through hole is filled with a conductive material to flatten the upper surface of the conductive material so as to be flush with the upper surface of the insulating layer, and the insulating layer including the flattened upper surface of the conductive material is formed. By forming the pixel electrode on the upper surface of the layer,
An upper surface of the pixel electrode which is in contact with the liquid crystal layer is formed flat.

Further, the pixel electrode is formed in a film shape on an insulating layer including the through hole, and an embedding member is buried in a concave portion formed at a position corresponding to the through hole on the upper surface of the pixel electrode, thereby forming the pixel electrode. A pixel driving element in which the upper surface in contact with the liquid crystal layer of the electrode is flattened may be formed.

Here, it is preferable that the embedding member is made of a light-reflective material. The “light-reflective material” refers to a material having the same reflectivity as the material of the pixel electrode, that is, a material having a degree of reflectivity that is normally required on the upper surface of the pixel electrode, and is made of the same material as the pixel electrode. It may be something.

Further, a concave portion formed at a position corresponding to the through hole on the upper surface of the pixel electrode layer is formed on the insulating layer including the through hole with a pixel electrode layer serving as the pixel electrode from a desired upper surface position of the pixel electrode. The pixel electrode layer is formed so as to be also upward, and the pixel electrode layer is removed from the upper surface thereof to the position of the desired pixel electrode upper surface to form a pixel electrode having a flat upper surface in contact with the liquid crystal layer, thereby producing a pixel driving element. May be.

Here, the "pixel electrode layer to be a pixel electrode" refers to a layer which is processed and becomes a pixel electrode.

[0011]

According to the present invention, there is provided a reflective active matrix type pixel driving element for a liquid crystal display, in which a through-hole provided in an insulating layer is filled with a conductive material to form an upper surface of the insulating layer on which the pixel electrode is formed. By flattening and forming the pixel electrode on the flattened surface, or corresponding to the through-hole on the upper surface thereof in order to form the pixel electrode in a film on the insulating layer having the through-hole. By embedding an embedding member in a recess formed at the position, or after forming a pixel electrode layer to be the pixel electrode sufficiently thicker than a desired thickness, the pixel electrode layer is removed from its upper surface to the desired thickness. As a result, since the upper surface of the pixel electrode in contact with the liquid crystal layer is formed flat, irregular reflection of light and distortion of lines of electric force caused by the presence of the concave portion on the upper surface are prevented. Flip no.

Therefore, it is possible to prevent the image quality of the liquid crystal display from deteriorating due to the irregular reflection of light and the distortion of the lines of electric force, which have conventionally occurred due to the concave portion on the upper surface of the pixel electrode.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a part of a cross section of a reflective active matrix type pixel driving element for a liquid crystal display according to a first embodiment of the present invention. This pixel driving element 1
A plurality of active elements formed on a substrate;
An insulating layer 4 having a through hole 5 formed on the substrate 2 so as to cover the insulating layer 4; a conductive material 6 filling the through hole 5 formed in the insulating layer 4;
And a pixel electrode 7 made of Al or the like formed on the surface of the insulating layer 4 and electrically connected to the active element 3 via the conductive material 6.

The above-mentioned pixel driving element 1 is produced as follows.

First, a plurality of active elements 3 are formed on a substrate 2, and an insulating layer 4 is formed on the substrate 2 so as to cover the active elements 3. Next, through holes 5 are formed in the insulating layer 4 at positions corresponding to the respective active elements 3 in order to electrically connect each of the active elements 3 to a pixel electrode 7 formed on the insulating layer 4 later. Thereafter, the through-hole 5 is filled with a conductive material 6 and a portion of the conductive material 6 protruding from the upper surface 4a of the insulating layer 4 is polished so that the upper surface 6a of the conductive material 6 is flattened. Make it the same height as the part (make it flush). The pixel electrode 7 is formed by vapor deposition on the surface of the insulating layer flattened in this manner (here, the upper surface 6a of the conductive material having the same height as the surface 4a of the insulating layer). This is referred to as a pixel drive element 1. At this time, since the pixel electrode 7 is formed on the flattened surface, it is not affected by the through hole 5 of the insulating layer 4 and the upper surface 7a which is in contact with the liquid crystal layer.
Is a flat surface without a concave portion.

FIG. 2 shows a part of a cross section of a reflection type active matrix type pixel driving element for a liquid crystal display according to a second embodiment of the present invention. This pixel driving element 11
A plurality of active elements 13 formed on a substrate 12;
Formed on the substrate 12 so as to cover the
Because the insulating layer 14 having 15 and the pixel electrode 17 formed on the insulating layer 14 so as to fill the through hole 15 formed in the insulating layer 14, It comprises a recess 18 formed on the upper surface of the pixel electrode 17 and an embedding member 19 made of a light-reflective material that fills the recess 18.

The pixel driving element 11 is produced as follows.

First, a plurality of active elements 13 are formed on a substrate 12, and an insulating layer is formed on the substrate 12 so as to cover the active elements 13.
Form 14. Next, through holes 15 are formed in the insulating layer 14 at positions corresponding to the respective active elements 3 in order to electrically connect each active element 13 to a pixel electrode 17 formed on the insulating layer 14 later. Thereafter, a pixel electrode 17 is formed by vapor deposition on the insulating layer 14 having the through hole 15.
At this time, since the pixel electrode material is uniformly deposited on the through hole 15, a concave portion 18 is formed at a position corresponding to the through hole 15 on the upper surface 17a of the pixel electrode 17. Then, this recess 18
The embedding member 19 is buried in the upper surface of the embedding member 19 by polishing a portion of the embedding member 19 protruding from the upper surface 17a of the pixel electrode.
19a is the same height as the flat portion of the upper surface 17a of the pixel electrode.
In this way, the pixel driving element 11 having a flat surface (here, including the upper surface 19a of the embedding member which is at the same height as the upper surface 17a of the pixel electrode) is formed.

Note that the same material as the pixel electrode 17 may be used for the embedded member.

FIG. 3 shows a part of a cross section of a reflective active matrix type pixel driving element for a liquid crystal display according to a third embodiment of the present invention. This pixel drive element 21
A plurality of active elements 23 formed on a substrate 22;
Formed on the substrate 22 so as to cover the
An insulating layer 24 having an insulating layer 25 and a pixel electrode 27 formed so as to fill a through hole 25 formed in the insulating layer 24 are formed.

The pixel drive element 21 is formed as follows.

First, a plurality of active elements 23 are formed on a substrate 22, and an insulating layer is formed on the substrate 22 so as to cover the active elements 23.
Form 24. Next, through holes 25 are formed in the insulating layer 24 in order to electrically connect each active element 23 to a pixel electrode 27 formed on the insulating layer 24 later. Thereafter, a pixel electrode layer 27 is formed on the insulating film 24 having the through holes 25 by vapor deposition. At this time, the pixel electrode layer 27 is
27 'is formed sufficiently thicker than the required film thickness t. That is, since the pixel electrode material is uniformly deposited on the through hole 25, a concave portion 28 is formed at a position corresponding to the through hole 25 on the upper surface of the deposited pixel electrode layer 27, but the bottom of the concave portion 28 has a desired bottom. It is thick enough to be above the pixel electrode upper surface position. After that, the pixel electrode layer 27 is removed from its upper surface to a desired pixel electrode upper surface position, and a pixel electrode 27 ′ having a thickness t is formed to obtain a pixel drive element 31. At this time, the pixel electrode layer 27
The upper surface 27'a of the pixel electrode 27 'formed by removing the upper part of the pixel electrode 27' and contacting the liquid crystal layer is a flat surface which is not affected by the through hole 25.

In the reflective active matrix type pixel driving element for a liquid crystal display according to each of the above embodiments, the upper surface of the pixel electrode in contact with the liquid crystal layer is flat. It is possible to prevent the image quality of the liquid crystal display from deteriorating without causing irregular reflection of light, distortion of lines of electric force, etc. occurring therein.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a part of a pixel driving element of a liquid crystal display according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of a part of a pixel driving element of a liquid crystal display according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of a part of a pixel driving element of a liquid crystal display according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pixel drive element 2 Substrate 3 Active element 4 Insulating layer 5 Through hole 6 Conductive material 7 Pixel electrode

Claims (6)

[Claims] 1. An active element formed on a substrate, an insulating layer formed on the active element and having a through hole at a position corresponding to the active element, and the through layer formed on the insulating layer. A reflective active matrix type liquid crystal display pixel drive element comprising a pixel electrode electrically connected to the active element through a hole, wherein an upper surface of the pixel electrode in contact with a liquid crystal layer is flat. Pixel driving element for a liquid crystal display. 2. An active element is formed on a substrate, an insulating layer having a through hole at a position corresponding to the active element is formed on the active element, and the insulating layer is formed on the insulating layer via the through hole. Forming a pixel electrode electrically connected to the active element, a method for producing a reflective active matrix type liquid crystal display pixel driving element, wherein the through hole is formed of a conductive material before forming the pixel electrode. By filling and flattening the upper surface of the conductive material so as to be flush with the upper surface of the insulating layer, forming the pixel electrode on the upper surface of the insulating layer including the flattened upper surface of the conductive material. Forming a flat top surface of the pixel electrode in contact with the liquid crystal layer. 3. An active element is formed on a substrate, an insulating layer having a through hole at a position corresponding to the active element is formed on the active element, and the insulating layer is formed on the insulating layer via the through hole. Forming a pixel electrode electrically connected to the active element, a method for producing a reflective active matrix type liquid crystal display pixel driving element, wherein the pixel electrode is formed into a film on an insulating layer including the through hole. A pixel for a liquid crystal display, wherein an embedded member is buried in a recess formed at a position corresponding to the through hole on the upper surface of the pixel electrode, and the upper surface of the pixel electrode in contact with a liquid crystal layer is flattened. How to create a drive element. 4. The method according to claim 3, wherein the embedding member is made of a light-reflective material. 5. The method according to claim 3, wherein the embedding member is made of the same material as the pixel electrode. 6. An active element is formed on a substrate, an insulating layer having a through hole at a position corresponding to the active element is formed on the active element, and the insulating layer is formed on the insulating layer via the through hole. A method for producing a pixel drive element for a reflective active matrix type liquid crystal display, wherein a pixel electrode electrically connected to the active element is formed, wherein a pixel electrode layer serving as the pixel electrode is insulated including the through hole. On the layer, a concave portion formed at a position corresponding to the through hole on the upper surface of the pixel electrode layer is formed so as to be thicker than a desired pixel electrode upper surface position. A method for producing a pixel driving element for a liquid crystal display, comprising forming a pixel electrode having a flat upper surface in contact with a liquid crystal layer by removing the pixel electrode to the upper surface position of the pixel electrode.