JP2000162625A - Color reflection type liquid crystal display device and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color reflection type liquid crystal display device, which does not produce misalignment of colors due to color shift and display pixels of the color filters, when the substrates are bonded, and to provide its producing method. SOLUTION: Each dye layers 20R, 20G 20B of color filters is formed on respective reflection display electrode 19 on a TFT substrate 10. Then a light- diffusing layer 22 is formed thereon, and a transparent electrode 23 having the same refractive index as that of the light-diffusing layer 22 is formed. The reflection display electrodes 19 are connected with transparent electrodes 23 through contact holes, formed in the color filters 20 and the light-diffusing layer 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color reflection type liquid crystal display device having a dye layer and a light diffusion layer, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, there has been proposed a so-called reflection type liquid crystal display device for displaying a display by reflecting light incident from an observation direction.

FIG. 3 is a sectional view of a conventional reflection type liquid crystal display device.

As shown in FIG. 1, a conventional reflection type liquid crystal display device has a TF made of quartz glass, non-alkali glass or the like.
A thin film transistor (hereinafter, referred to as “TFT”) as a switching element is formed over T10. Hereinafter, the TFT 10 on which the TFT is formed is referred to as a TFT substrate.

First, chrome (C) is formed on a TFT substrate 10.
r), a gate electrode 11 made of a refractory metal such as molybdenum (Mo), a gate insulating film 12, and an active layer 13 made of a polycrystalline silicon film are sequentially formed.

The active layer 13 has a channel 13c above the gate electrode 11, and a source 13s and a drain 1 formed on both sides of the channel 13c by ion implantation using the stopper insulating film 14 on the channel 13c as a mask.
3d is provided.

Then, an SiO ₂ film, a SiN film, and the like are formed on the entire surface of the gate insulating film 12, the active layer 13, and the stopper insulating film 14.
An interlayer insulating film 15 is formed by laminating a film and an SiO ₂ film in this order, and a contact hole provided corresponding to the drain 13 d is filled with a metal such as aluminum (Al) to form a drain electrode 16. Further, a flattening insulating film 17 made of, for example, an organic resin and flattening the surface is formed on the entire surface. Then, a contact hole is formed at a position corresponding to the source 13 s of the planarization insulating film 17, and a reflection electrode which is made of aluminum (Al) contacted with the source 13 s via the contact hole and also serves as the source electrode 18. The display electrode 19 is formed on the flattening insulating film 17.
Then, an alignment film 20 made of an organic resin such as polyimide for aligning the liquid crystal 21 is formed on the reflective display electrode 19.

A counter electrode substrate 30, which is an insulating substrate made of quartz glass, non-alkali glass, or the like, which faces the TFT substrate 10, has red (R), green (G), and blue on the TFT substrate 10 side. (B) A color filter 31 including a black matrix 32 having each color and a light shielding function, a protective film 33 made of resin formed thereon to protect the color filter 31, and light formed on the entire surface of the protective film 33. A diffusion layer 34, a counter electrode 35, and an alignment film 36;
A retardation plate 44 and a polarizing plate 45 are disposed on the opposite surface. Then, the periphery of the counter electrode substrate 30 and the periphery of the TFT substrate 10 are adhered by a seal adhesive (not shown), and a twisted nematic (T
N) The liquid crystal 21 is sandwiched.

As shown by the solid arrows, natural light 100 entering from the outside enters from the polarizing plate 45 on the observer 101 side, and the phase difference plate 44, the counter electrode substrate 30, the color filter 31, the protective film 33, and the light The light reaches the diffusion layer 34, and the light is diffused by the light diffusion layer 34, and the diffused light is transmitted to the counter electrode 35, the alignment film 36, the TN liquid crystal 21, and the TFT substrate 1.
0, and is reflected by the reflective display electrode 19, then passes through each layer in the direction opposite to the incident direction, exits from the polarizing plate 45 on the counter electrode substrate 30, and exits from the observer's eye 101.
to go into.

As described above, the protection film 3 of the counter electrode substrate 30 is formed.
When a light diffusion layer 34 is provided on the light diffusion layer 3, incident light is diffused by the light diffusion layer 34. Then, the diffused light travels in multiple directions and is reflected by the reflective display electrode 19 before reaching the eyes of the observer 101.

[0011]

However, as shown in FIG. 3, when the periphery of the TFT substrate 10 and the periphery of the counter electrode substrate 30 are adhered to each other with an adhesive sealant and bonded to each other, a reflection type liquid crystal display device is manufactured. In addition, it is necessary to prevent each color of the color filter on the counter electrode substrate 30 from being displaced from each display pixel on the TFT substrate 10. Therefore, it takes a very long time to bond both substrates, and there is a drawback that color blur occurs due to misregistration.

In view of the above, the present invention has been made in view of the above-mentioned conventional drawbacks, and does not require precise alignment when bonding both substrates, and provides a uniform and bright display without color bleeding. It is an object of the present invention to provide a color reflective liquid crystal display device and a method of manufacturing the same.

[0013]

According to the present invention, there is provided a color reflection type liquid crystal display device comprising a first and a second liquid crystal display devices which are arranged to face each other.
A liquid crystal is sandwiched between the substrates, and the first substrate has a switching element, a reflective display electrode connected to the switching element, a dye layer, a light diffusion layer on the reflective display electrode, and the reflective display electrode. The second substrate is provided with a counter electrode facing the reflective display electrode on the second substrate.

In the above-mentioned color reflection type liquid crystal display device, the material constituting the transparent electrode and the light diffusion layer have the same refractive index.

Further, there is provided a method of manufacturing a color reflection type liquid crystal display device in which a liquid crystal is sandwiched between first and second substrates arranged opposite to each other, wherein a switching element is formed on the first substrate. Forming a planarizing insulating film covering the entire surface including the switching element; and connecting the switching element via the contact hole provided in the planarizing insulating film to the switching element, and performing reflection display on the planarizing insulating film. Forming an electrode, forming a dye layer and a light diffusion layer on the reflective display electrode, and forming a transparent electrode connected to the reflective display electrode via a contact hole provided in the light diffusion layer. And a step of forming a counter electrode facing the reflective display electrode on the second substrate.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A color reflection type liquid crystal display device of the present invention will be described below.

FIG. 1 is a cross-sectional view of a color reflection type liquid crystal display device of the present invention, and FIG. 2 is a cross-sectional view of a manufacturing process on a TFT substrate side.

As shown in FIG. 1, in the case of this embodiment,
Since the steps from the formation of the gate electrode 11 made of a high melting point metal such as Cr and Mo to the formation of the planarization insulating film 17 on one TFT substrate 10 are the same as those of the above-described structure, the description is omitted.

On the flattening insulating film 17, A is connected to the source 13s of the active layer 13 made of a polycrystalline silicon film.
1. A reflective display electrode 19 made of a conductive reflective material such as silver (Ag) is formed. Also, on this reflective display electrode 19,
Black matrix 20BM having each color of red (R) 20R, green (G) 20G, and blue (B) 20B and a light shielding function
Is formed. A light diffusion layer 22 for diffusing light is formed on the entire surface. Further thereon, a transparent electrode 23 made of a transparent conductive material such as ITO (Indium Thin Oxide), which is in contact with the reflective display electrode 19 through a light diffusion layer 22 and a contact hole provided in a color filter, is formed. .

The reason why the transparent electrode 23 is provided on the reflective display electrode 19 via the color filters 20R, 20G, 20B and the contact holes provided in the light diffusion layer 34 is as follows.
The light diffusion layer 34 formed on the reflective display electrode 19 has capacitance, and the liquid crystal 25 applied to the reflective display electrode 19
This is to prevent the voltage to be applied from being dropped from being applied to the liquid crystal 25 from dropping.

Further, the transparent electrode 23 is
, Or larger than the reflective display electrode 19. By doing so, the voltage applied to the liquid crystal 25 can be sufficiently applied to the liquid crystal 23. And
The liquid crystal 2 is made of polyimide or the like on the entire surface including the transparent electrode 23.
Then, an alignment film 24 for orienting 5 is formed.

A counter electrode substrate 30 made of an insulating substrate such as quartz glass or non-alkali glass has a counter electrode 31 facing each transparent electrode 23 on the side where the liquid crystal 25 is disposed.
Are provided on the entire surface. Further, an alignment film 32 made of polyimide is formed on the entire surface.

On the side of the counter electrode substrate 30 where no liquid crystal is arranged, that is, on the observation 101 side, a phase difference (λ / 4) plate 34 is provided.
And a polarizing plate 35 are provided in order from the counter electrode substrate 30 side.

The periphery of the TFT substrate 10 and the counter electrode substrate 30 manufactured as described above is adhered with an adhesive sealing material (not shown), and the liquid crystal 2 is inserted into a gap formed by the adhesion.
5. Filling, for example, TN liquid crystal, completes the liquid crystal display device.

Here, how the light incident from the outside proceeds will be described.

Natural light 100 incident from the outside is shown in FIG.
As shown by the dotted arrow inside, the polarizing plate 3 on the observer 101 side.
5 through the phase difference plate 34, the counter electrode substrate 30, the counter electrode 31, the alignment film 32, and the liquid crystal 25, and
The light passes through the alignment film 24 on the substrate 10 and reaches the transparent electrode 23 and the light diffusion layer 22. Then, the light is diffused, and the diffused light passes through the color filter 20 and is reflected by the reflective display electrode 19.
To reach. The arriving light is reflected by the reflective display electrode 19. The reflected light passes through the optical path opposite to that of the incident light, passes through the phase difference plate 34 and the polarizing plate 35, and passes through the observer 101.
To be observed.

A method of manufacturing a TFT substrate will be described with reference to FIG. It should be noted that only the cross section of the upper layer including the planarization insulating film 17 is shown in the process drawings after FIG.

FIG. 2A: A TFT as a switching element is formed on a TFT substrate 10 made of quartz glass, non-alkali glass or the like.

On the TFT substrate 10, a gate electrode 11 made of a high melting point metal such as chromium (Cr) and molybdenum (Mo), a gate insulating film 12, and an active layer 13 made of a polycrystalline silicon film are sequentially formed.

The active layer 13 has a channel 13c above the gate electrode 11, and a source 13s and a drain 1 formed on both sides of the channel 13c by ion implantation using the stopper insulating film 14 on the channel 13c as a mask.
3d is provided.

Then, an SiO ₂ film, a SiN film, and the like are formed on the entire surface of the gate insulating film 12, the active layer 13, and the stopper insulating film 14.
An interlayer insulating film 15 is formed by laminating a film and an SiO ₂ film in this order, and a contact hole provided corresponding to the drain 13 d is filled with a metal such as aluminum (Al) to form a drain electrode 16. Further, a flattening insulating film 17 made of, for example, an organic resin and flattening the surface is formed on the entire surface. Then, a contact hole is provided in the planarizing insulating film 17.

FIG. 2B: A conductive reflective material such as Al or silver (Ag) is deposited on the planarizing insulating film 17 provided with the contact hole, and a reflective display electrode 19 is formed by photolithography.

Then, a color filter as a dye layer is formed thereon. First, a resist containing a red (R) pigment is applied to the entire surface with a spinner or the like, and exposure is performed using a mask 26.

FIG. 2C: A red color filter 20 R is formed on the reflective display electrode 19 by removing the red pigment and the mask other than the area covered by the mask.

FIG. 2D: Similarly, the other G, B and black matrices 32 are sequentially formed by exposing the resist containing the green, blue and black pigments to a mask.

FIG. 2E: The color filter 20
The light diffusion layer 22 is applied to the entire surface of the substrate by a spinner. The light diffusion layer 22 is made of an acrylic resin as a base material and mixed with bead particles in the base material, thereby diffusing incident light. In the case of the present embodiment, an acrylic resin having a refractive index of 1.4 to 1.6 was used. Then, a contact hole is provided in the light diffusion layer 22. At this time, the color filter also penetrates at the same time,
A contact hole is provided to reach the reflective display electrode 19.

FIG. 2 (f): Thereafter, a transparent conductive material having a refractive index equal to that of the light diffusion layer 22, for example, ITO is deposited on the entire surface of the light diffusion layer 22, and has an area approximately equal to or slightly larger than that of the reflective display electrode 19. The transparent electrode 23 is formed. An alignment film 24 for aligning the liquid crystal 25 is formed on the entire surface.
Thus, the TFT substrate 10 is completed. Both substrates 1 described above
A liquid crystal display device is completed by bonding the periphery of 0 and 30 with an adhesive sealing material. At this time, in the case of a conventional color reflection type liquid crystal display device, the transparent electrode 23 provided on the TFT substrate 10
In addition, it is necessary to accurately align the respective color filters on the counter electrode substrate 30 having a size corresponding to the transparent electrode 23 without displacement. Should the position shift, the adjacent colors would be mixed, causing color bleeding.

However, according to the color reflection type liquid crystal display device of the present invention, the color filters of each color are formed by the reflection display electrode 1.
Since the substrates 9 and 9 are provided with high accuracy by pattern formation, highly accurate alignment of the substrates 10 and 30 is not required, so that the bonding process can be shortened and the occurrence of color bleeding due to displacement can be prevented.

When the light diffusing layer 22 is provided on the counter electrode substrate 30, a part of the incident light is scattered backward by the light diffusing layer 22, and the light does not reach the liquid crystal 25 layer. Although the light was emitted to the observer 101 side, since the light diffusion layer 22 is provided on the TFT substrate 10, all the incident light reaches the TFT substrate 10 side, and all of the incident light passes through the liquid crystal 25 layer, and the observer receives the light. It will be emitted to the 101 side. Therefore,
The light incident from the observer 101 side and reaching the transparent electrode 23 and the reflective display electrode 19 on the TFT substrate 10 side is all liquid crystal 25
Since light is transmitted or blocked by the layer and contributes to display, light can be efficiently used, whereby a uniform and bright display can be obtained.

Further, the light diffusion layer 34 is formed on the reflective display electrode 19.
Is provided, since the light diffusion layer 34 has a capacitance, the voltage applied to the reflective display electrode 19 drops, and the voltage that should be applied to the liquid crystal 23 is not applied to the liquid crystal 25. Therefore, in order to prevent this, the transparent electrode 23 connected to the reflective display electrode 19 through the color filter and the contact hole provided in the light diffusion layer 34 is provided on the light diffusion layer 34. Therefore, the transparent electrode 23 is provided on the light diffusion layer 34 because the liquid crystal 25 cannot be applied. That is,
Since the transparent electrode 23 is connected to the reflective display electrode 34 via the contact hole provided in the light diffusion layer 34, the transparent electrode 23 is applied to the reflective display electrode 19 without causing a voltage drop when a voltage is applied by the reflective display electrode 19. The applied voltage is applied to the liquid crystal 25.

Further, since the light diffusing layer 22 and the transparent electrode 23 have the same refractive index, it is possible to prevent the light from being reflected by the light diffusing layer 22 and generating light that does not reach the color filter. That is, as shown by a dotted arrow in FIG.
3 is not reflected by the light diffusion layer 22,
The light enters the light diffusion layer 22 and the color filter and is reflected by the reflective display electrode, so that the color of each pixel can be observed by an observer.

[0042]

According to the present invention, it is not necessary to precisely align the pixel portions of the two substrates, so that the process can be simplified and a color reflection that can obtain a uniform and bright display without color bleeding can be obtained. Liquid crystal display device is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view of a color reflection type liquid crystal display device of the present invention.

FIG. 2 is a cross-sectional view illustrating a manufacturing process of the color reflective liquid crystal display device of the present invention.

FIG. 3 is a cross-sectional view of a conventional color reflection type liquid crystal display device.

DESCRIPTION OF SYMBOLS 10 TFT substrate 13 Active layer 15 Interlayer insulating film 17 Flattening insulating film 19 Reflective display electrode 20R Color filter 20B Color filter 20R Color filter 22 Light diffusion layer 23 Transparent electrode 24 Alignment film 25 Liquid crystal 30 Counter electrode substrate 34 Phase plate 35 Polarizing plate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA02Y FA14Y FA31Y FC01 FD04 FD06 GA13 KA01 LA16 LA18 2H092 JA26 JA36 JA40 JA44 JA46 JB04 JB07 JB56 JB58 KA04 KA18 KB13 MA10 MA15 MA27 MA37 NA03 NA27 PA08 PA12

Claims (3)

[Claims] 1. A first and a second arrangement arranged opposite to each other.
Liquid crystal is sandwiched between the substrates, and the first substrate includes:
A switching element, a reflective display electrode connected to the switching element, a dye layer and a light diffusion layer provided on the reflective display electrode, and a contact hole provided on the dye layer and the light diffusion layer on the light diffusion layer. A color reflective liquid crystal display device comprising: a transparent electrode connected to the reflective display electrode; and a counter electrode facing the reflective display electrode on the second substrate. 2. The color reflection type liquid crystal display device according to claim 1, wherein the material constituting the transparent electrode and the light diffusion layer have the same refractive index. 3. A first and a second arrangement arranged opposite to each other.
A method of manufacturing a color reflection type liquid crystal display device in which liquid crystal is sandwiched between substrates, wherein a step of forming a switching element on the first substrate and a planarizing insulating film covering the entire surface including the switching element are provided. Forming, a step of forming a reflective display electrode on the planarized insulating film connected to the switching element via a contact hole provided in the planarized insulating film, and a dye layer and light on the reflective display electrode. Forming a diffusion layer;
Forming a transparent electrode connected to the reflective display electrode via a contact hole provided in the dye layer and the light diffusion layer; and forming a counter electrode facing the reflective display electrode on the second substrate. And a method of manufacturing a color reflection type liquid crystal display device.