JP2003255331A - Semitransmissive liquid crystal display and method for manufacturing liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reflectance in relation to a semitransmissive liquid crystal display. <P>SOLUTION: The semitransmissive liquid crystal display is provided with a reflection part to reflect light and a transmission part to transmit light, has a transparent electrode layer on the transmission part to transmit the light, and has a reflection plate which has no transparent electrode layer on the reflection part to reflect the light. When the transparent electrode layer is not formed on the reflection layer but formed only on the transmission part to transmit light, the reflectance is improved because the light reflected on the reflection layer is reflected without being absorbed by the transparent electrode layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transflective liquid crystal display device having a reflector.

[0002]

2. Description of the Related Art In recent years, as personalization of information has progressed, information terminal devices that emphasize portability have been rapidly developed, as seen in higher performance of mobile phones. For long-term operation with a battery and reduction in thickness and weight, which are the key points of portability, it is possible to display without a backlight by using a backlight in a dark environment and reflecting ambient light in a bright environment. The transflective liquid crystal display device has attracted attention. As a transflective liquid crystal display device and a method for manufacturing the same, the one described in Japanese Patent Application Laid-Open No. 11-281992 is known.

FIG. 3 is a cross-sectional view of a conventional transflective liquid crystal display device and its manufacturing method.

In FIG. 3, 1 is a substrate, 2, 3, 4, 5,
Reference numerals 6 and 7 denote a gate electrode, a gate insulating film, a channel layer, a contact layer, a source electrode, and a drain electrode, respectively, which are thin film transistors (TF).
Abbreviated as T. ) Is formed. Reference numeral 8 is an interlayer insulating film having a contact hole 8a and a concavo-convex portion 8b, and 9 and 10 are a transparent electrode and a reflection plate respectively constituting a pixel electrode. Two
Reference numeral 0 is a protective film having an opening of 20a.

First, after the gate electrode 2 is patterned on the substrate 1, a gate insulating film 3 covering the entire surface, a channel layer 4 in the vicinity of the gate insulating film 3 on the gate electrode 2, and a low layer on both ends of the channel layer 4 are formed. Resistive contact layer 5 and source electrode 6
The drain electrode 7 and the drain electrode 7 are overlapped to form a TFT array. Next, the contact hole 8 on the drain electrode 7
An interlayer insulating film 8 having an a and an uneven portion 8b and made of an organic resin film is formed.

Next, after forming a film of Al as a reflecting plate material, the reflecting plate 10 having an uneven shape is formed on the uneven portion 8b by photolithography.

Next, after forming a film of indium tin oxide (hereinafter abbreviated as ITO) as a transparent electrode material, a transparent electrode 9 is formed by photolithography to obtain an active element array substrate (see FIG. 3).

Further, a liquid crystal display device is completed by adhering a counter substrate having a color filter and a transparent electrode to the above active element array substrate so as to face it, and enclosing a liquid crystal therebetween.

As described above, there are two types of pixel electrodes, that is, the reflection plate 10 having a function as a reflection plate for reflecting ambient light and the transparent electrode 9 having a function as a transmission plate for transmitting light from the backlight. By using the pixel electrode composed of electrodes, a semi-transmissive liquid crystal display device in which both the reflection characteristic and the transmission characteristic are optimized can be obtained. Therefore, it is possible to obtain a liquid crystal display device having excellent visibility in both dark and bright environments.

[0010]

However, according to the liquid crystal display device using the reflection plate and the transparent electrode as the pixel electrode as described above, good reflection characteristics can be realized. There is a problem that the reflected light is absorbed by the transparent electrode layer formed on the reflection plate and the reflectance is lowered.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to realize a high reflectance by removing the transparent electrode layer on the reflector. An object is to provide a transmissive liquid crystal display device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is
A liquid crystal and a pair of substrates sandwiching the liquid crystal, which face each other, a reflector formed on the inner surface of one of the pair of substrates, and an illumination which supplies light to the pair of substrates from the side of the one substrate. A semi-transmissive liquid crystal display device comprising: a device, wherein the light reflected by the reflection plate and the amount of light supplied from the lighting device are controlled through the liquid crystal to perform display. The substrate is an active element having an electrode, an interlayer insulating film formed on the active element, having a flat surface and a concavo-convex surface, and a contact hole formed on the electrode of the active element, and an interlayer insulating film on the interlayer insulating film. A reflective plate formed and having at least a part having a function of reflection and scattering, and a function of transmission connected to the electrode of the active element through the contact hole. A first transparent electrode layer formed of a bright conductive film; and a second transparent electrode layer formed of a transparent conductive film having a transmission function, which is formed on the interlayer insulating film and the reflection plate, The reflector has a reflecting portion that reflects light and a transmitting portion that transmits light on the surface.

The invention according to claim 2 of the present invention is the semi-transmissive liquid crystal display device according to claim 1, wherein the one substrate on which the reflector is formed comprises a flat bottom portion and the bottom portion. It has a convex part which projects, and the above-mentioned reflector is provided in at least one copy of the convex part.

According to a third aspect of the present invention, in the semi-transmissive liquid crystal display device according to the first aspect, the reflecting plate formed on the interlayer insulating film having the uneven surface has a convex portion. It is characterized by having and not having any transparent electrode layer on this convex part.

The invention according to claim 4 of the present invention is the transflective liquid crystal display device according to any one of claims 1 to 3, wherein the transparent electrode layer is made of indium tin oxide. Characterize.

The invention according to claim 5 of the present invention is the transflective liquid crystal display device according to any one of claims 1 to 4, wherein the reflector is Al or Al alloy, Ag or Ag alloy. It is characterized by consisting of.

According to a sixth aspect of the present invention, there is provided a step of forming an active element on a glass substrate, a step of forming an interlayer insulating film having a flat surface and an uneven surface on the active element, Forming a contact hole on the electrode of the active element of an insulating film, and forming a reflecting plate having a function of reflection and scattering on the entire surface of the interlayer insulating film, and then forming at least the reflecting plate on the contact hole. A step of removing, a step of forming a transparent electrode layer on the interlayer insulating film and the reflector so as to connect to the electrode of the active element through the contact hole, and a step of removing the transparent electrode layer on the reflector. And a step of manufacturing a liquid crystal display device.

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

FIG. 1 shows a cross-sectional structure of a pixel portion in an active element array of a semi-transmissive liquid crystal display device, and FIG. 2 shows a cross-sectional structure in the manufacturing process for each process.

The same components as those of the liquid crystal display device and the manufacturing method thereof shown in FIG. 3 as a conventional example are designated by the same reference numerals and detailed description thereof will be omitted.

First, 100/200/100 nm of Ti / Al / Ti are laminated on the substrate 1 made of glass by a sputtering method using Ar gas to form a film, and then the gate electrode 2 is processed and formed. Next, plasma chemical vapor deposition (hereinafter p-
Abbreviated as CVD method. ), SiNx, a-Si, low resistance a-
After forming the three layers of Si, a-Si and low-resistance a-Si other than the TFT region are removed by etching to form the island-shaped channel layer 4, the contact layer 5, and the gate insulating film 3 over the entire surface.

Next, Ti / Al / Ti is laminated again by a sputtering method using Ar gas to form a film, and then the TFT is formed.
Are processed into the pattern of the source electrode 6 and the drain electrode 7. At the same time, the contact layer 5 is separately formed in the source and drain regions. Next, p-CV on the entire surface
By forming the protective film 20 made of SiNx as the protective film of the channel layer 4 by the D method, a TFT array is obtained (FIG. 2).
(a)).

Next, the protective film 20 is processed using the resist as a mask to form an opening 20a on the drain electrode 7 (FIG. 2 (b)). Next, after applying a photosensitive acrylic resin on the entire surface by about 3 μm, the interlayer insulating film 8 having the contact hole 8a, the uneven portion 8b, and the plane portion 8c in the opening 20a is formed by exposure and development (FIG. 2 (c)). .

Next, as a reflection plate (reflection layer) 21, Al or
An Al alloy film is formed and patterned using a resist mask (FIG. 2D). Next, a transparent ITO film is formed as a pixel electrode layer. Next, most of the reflection plate (reflection layer) 2
No ITO layer is formed on 1 and a resist mask is formed so that a part of ITO overlaps the reflection plate 21, and then a transparent electrode layer to be a pixel electrode is processed by using a phosphoric acid-based etchant using the resist mask. To do.

In this way, the first transparent electrode layer 22 connected to the drain electrode of the active element through the contact hole and the second transparent electrode layer 23 formed on the interlayer insulating film and the reflection layer are formed. Form.

Finally, the resist mask is removed to obtain an active element array substrate (FIG. 2 (e)).

Further, similarly to the conventional example, a counter substrate having a color filter and a transparent electrode is attached to the above active element array substrate so as to face the active element array substrate, and liquid crystal is sealed between both substrates. Use as a display device. Then, a semi-transmissive liquid crystal display device is completed by providing the liquid crystal display device with a lighting device called a backlight on the array substrate side.

According to the above-described embodiment, the transparent electrode layer is not formed on most of the reflection plate (reflection layer), and the transparent electrode layer is formed only in the transmissive portion through which almost light is transmitted. Therefore, the light reflected on the reflective layer is not absorbed by the transparent electrode layer, and high reflectance can be realized.

[0029]

As described above, according to the present invention,
Since the light reflected on the reflector is reflected without being absorbed by the transparent electrode layer, it is possible to improve the reflectance and obtain a liquid crystal display device capable of bright display even in an environment without a backlight. , Its practical effect is great.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a pixel portion in an active element array of a transflective liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a method of manufacturing a semi-transmissive liquid crystal display device according to an embodiment of the present invention for each step of the active element array.

FIG. 3 is a cross-sectional view of a conventional transflective liquid crystal display device.

[Explanation of symbols]

1 glass substrate 2 Gate electrode 3 Gate insulation film 4 channel layers 5 Contact layer 6 Source electrode 7 Drain electrode 8 Interlayer insulation film 8a contact hole 8b uneven part 9 Transparent electrode 10 Reflector 20 Protective film 20a opening 21 Reflector 22 First transparent electrode layer 23 Second transparent electrode layer

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshikazu Sakurai             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Koba Baba             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Motoaki Aoki             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Seiji Nishiyama             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 2H091 FA14Y FB08 FC01 GA03                       GA13 LA16                 2H092 JA24 JA46 JB57 KA05 KB24                       KB25 MA05 MA17 NA01 PA12                 5F110 AA30 BB01 CC07 EE03 EE04                       EE15 FF03 FF30 GG02 GG15                       GG45 HK03 HK04 HK09 HK14                       HK22 HK33 HK35 HL07 NN03                       NN24 NN27 NN35 NN36 NN72

Claims (6)

[Claims] 1. A liquid crystal and a pair of substrates sandwiching the liquid crystal, which face each other, a reflector formed on the inner surface of one of the pair of substrates, and a pair of substrates from the side of the one substrate. A transflective liquid crystal display device comprising a lighting device that supplies light, and performing display by controlling the amount of light reflected by the reflector and the amount of light supplied from the lighting device via the liquid crystal. The one substrate is an active element having an electrode, an interlayer insulating film formed on the active element, having a flat surface and a concavo-convex surface, and a contact hole formed on the electrode of the active element, A reflector, which is formed on the interlayer insulating film and has at least a part of a function of reflecting and scattering, and a transparent plate which is connected to the electrode of the active element through the contact hole. A first transparent electrode layer formed of a transparent conductive film having a function of; and a second transparent electrode layer formed of a transparent conductive film having a function of transmission formed on the interlayer insulating film and the reflection plate. The semi-transmissive liquid crystal display device, wherein the reflection plate has a reflection portion that reflects light and a transmission portion that transmits light on a surface thereof. 2. The one substrate on which the reflection plate is formed has a flat bottom portion and a convex portion protruding from the bottom portion, and the reflection plate is provided on at least a part of the convex portion. Item 2. A transflective liquid crystal display device according to item 1. 3. The transflective liquid crystal display according to claim 1, wherein the reflector formed on the interlayer insulating film having an uneven surface has a convex portion and does not have any transparent electrode layer on the convex portion. apparatus. 4. The transflective liquid crystal display device according to claim 1, wherein the transparent electrode layer is made of indium tin oxide. 5. The transflective liquid crystal display device according to claim 1, wherein the reflector is made of Al, Al alloy, Ag or Ag alloy. 6. A step of forming an active element on a glass substrate, a step of forming an interlayer insulating film having a flat surface and an uneven surface on the active element, and a contact on the electrode of the active element of the interlayer insulating film. A step of forming a hole, a step of forming a reflector having a function of reflection and scattering on the entire surface of the interlayer insulating film, and then removing the reflector at least on the contact hole; A method of manufacturing a liquid crystal display device, comprising: forming a transparent electrode layer on a plate so as to be connected to an electrode of the active element through the contact hole; and removing the transparent electrode layer on the reflection plate.