JPH05281533A - Reflection type liquid crystal display device and its manufacture - Google Patents

Abstract

PURPOSE:To provide a reflection type liquid crystal display device having excellent reflex characteristic by forming the sectional shape of a reflector out of fine convexities of doughnut-shape or mixture of circular-shape and doughnut- shape, and arranging the convexities irregularly. CONSTITUTION:A pair of transparent boards 31 face to each other sandwiching a liquid crystal layer. An insulating film 42 having irregularity is applied to a liquid crystal layer side on one of the boards 31, and thereon plural reflex electrodes 38, being display picture elements reflecting incident light from the other board side, are formed, and a common electrode, having translucency on nearly the whole face thereof, is formed on the liquid crystal side of the other board 31 so as to form a reflex liquid device. In the reflex liquid device, the sectional shapes of protrusions are a fine doughnut-shape 42a or mixed with a circular-shape 42b, and the arrangement thereof is irregular. As an irregular portion is formed by using a mask, the shapes, particularly the depths of dents are uniform. Therefore poor insulation is not allowed to give damage to elements, and scattered incident light allows bright reflex characteristic.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflection type liquid crystal display device for displaying by reflecting incident light and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, the application of liquid crystal display devices to word processors, laptop personal computers, pocket televisions, etc. has been rapidly developing. In particular, in the liquid crystal display device, a reflective liquid crystal display device that reflects light incident from the outside to display an image does not require a backlight as a light source, so consumes less power, and is thin and lightweight. Because of this, it is getting attention.

Conventionally, a TN has been used for a reflective liquid crystal display device.
Although the (twisted nematic) method and the STN (super twisted nematic) method are used, in these methods, 1/2 of the light intensity of natural light is not necessarily used for display due to the polarizing plate, and the display is There is a problem that it gets dark.

To solve such a problem, a display mode has been proposed in which all light rays of natural light are effectively used without using a polarizing plate. An example of such a mode is a phase transition type guest-host system (D.
L. White and G.M. N. Taylor: J.
Appl. Phys. 45 4718 1974). In this display mode, the cholesteric / nematic phase transition phenomenon due to the electric field is used. A reflective multi-color display in which a micro color filter is further combined with the phase transition type guest-host system has been proposed (Tohru Koizumi and Tatsu).
o Uchida, Proceedings of
he SID, Vol. 29, 157, 1988).

In order to obtain a brighter display in a mode that does not require such a polarizing plate, it is necessary to increase the intensity of light scattered in a direction perpendicular to the display screen with respect to incident light from all angles. .. For that purpose, it is necessary to create a reflector having optimum reflection characteristics. In the above-mentioned literature, the surface of a substrate made of glass or the like is roughened with an abrasive, the surface irregularities are controlled by changing the time for etching with hydrofluoric acid, and a silver thin film is formed on the irregularities. A reflector is described.

FIG. 10 is a plan view of a substrate 2 having a thin film transistor (hereinafter referred to as a TFT) 1 which is a switching element used in an active matrix system.
FIG. 11 is a sectional view taken along the section line XI-XI shown in FIG. On the insulating substrate 2 such as glass, chrome,
A plurality of gate bus wirings 3 made of tantalum or the like are provided in parallel with each other, and the gate electrode wirings 4 extend from the gate bus wirings 3 to the gate electrodes 4.
Are diverged. The gate bus wiring 3 functions as a scanning line.

Silicon nitride (SiN _x ) and silicon oxide (SiO _x ) are formed on the entire surface of the substrate 2 so as to cover the gate bus electrode 4.
A gate insulating film 5 made of, for example, is formed. Amorphous silicon (hereinafter referred to as a-Si), polycrystalline silicon, CdSe is formed on the gate insulating film 5 above the gate electrode 4.
A semiconductor layer 6 made of, for example, is formed. Semiconductor layer 6
A source electrode 7 made of titanium, molybdenum, aluminum or the like is superposed on one end of the first electrode. Further, similarly to the source electrode 7, a drain electrode 8 made of titanium, molybdenum, aluminum or the like is formed on the other end of the semiconductor layer 6 in an overlapping manner. At the end of the drain electrode 8 opposite to the semiconductor layer 6, ITO (Indium Tin Oxide) is formed.
A picture element electrode 9 composed of de) is formed in an overlapping manner.

As shown in FIG. 10, the source electrode 7 is connected to the source bus line 10 which intersects the gate bus line 3 with the gate insulating film 5 interposed therebetween. The source bus line 10 functions as a signal line. The source bus line 10 is also made of the same metal as the source electrode 7.
The gate electrode 4, the gate insulating film 5, the semiconductor layer 6, the source electrode 7 and the drain electrode 8 form the TFT 1 and
The FT1 has a function of a switching element.

If the substrate 2 having the TFT 1 shown in FIGS. 10 and 11 is applied to a reflection type liquid crystal display device,
Not only is the pixel electrode 9 formed of a metal having a light-reflecting property such as aluminum or silver, but it is necessary to form irregularities on the gate insulating film 5. Generally, it is difficult to uniformly form the tapered unevenness on the insulating film 5 made of an inorganic material.

FIG. 12 is a plan view of a substrate 12 having a TFT 11 used in the active matrix type,
FIG. 13 is a sectional view taken along the section line XII-XII shown in FIG. A plurality of gate bus wirings 1 made of chromium, tantalum, etc. on an insulating substrate 12 such as glass
3 are provided in parallel with each other, and a gate electrode 14 is branched from the gate bus line 13. The gate bus line 13 functions as a scanning line.

A gate insulating film 15 made of silicon nitride, silicon oxide or the like is formed on the entire surface of the substrate 12 so as to cover the gate electrode 14. A semiconductor layer 1 made of a-Si or the like is formed on the gate insulating film 15 above the gate electrode 14.
6 is formed. At both ends of the semiconductor layer 16, a-
A contact layer 17 made of Si or the like is formed.
A source electrode 18 is formed on one of the contact layers 17, and the drain electrode 1 is formed on the other contact layer 17.
9 are formed in an overlapping manner. The source electrode 18 is connected to the source bus line 10 that functions as a signal line that intersects the gate bus line 13 with the gate insulating film 15 interposed therebetween. Gate electrode 14, gate insulating film 15, semiconductor layer 1
6, the contact layer 17, the source electrode 18 and the drain electrode 19 form the TFT 11.

Further, it has a plurality of convex portions 20a on it,
An organic insulating film 20 having a contact hole 21 is formed on the drain electrode 19. A reflective electrode 22 is formed on the organic insulating film 20, and the reflective electrode 22 is connected to the drain electrode 19 via a contact hole 21.

The substrate 1 on which the TFT 11 is formed as described above
If the organic insulating film 20 is formed on the organic insulating film 20, the convex portion 20a can be easily formed on the surface of the organic insulating film 20 by an etching method, and the reflective electrode 22 is formed on the organic insulating film 20 having the convex portion 20a. The reflective electrode 22 having irregularities can be easily formed by forming the.

[0014]

In the reflection plate described in the above document, since the uneven portion is formed by scratching the glass substrate with the abrasive, the uneven portion having a uniform shape cannot be formed. In addition, since there is a problem that the shape of the uneven portion is poor in reproducibility and a problem that the shape of the uneven portion cannot be patterned, when such a glass substrate is used, the reflection that requires good reflection characteristics with good reproducibility is required. Type liquid crystal display device cannot be provided. Furthermore, this method cannot be applied to a substrate having a switching element such as a TFT because it may damage the device.

Further, as shown in FIGS. 10 and 11, when the reflective electrode 9 and the source bus line 10 are formed on the gate insulating film 5, the reflective electrode 9 and the source bus line 10 are electrically connected to each other. The gap 9a is formed so as not to. However, as shown in FIGS. 12 and 13, when the source bus line 23 is formed on the gate insulating film 15 and the reflective electrode 22 is formed on the organic insulating film 20, the gap 9a as described above is unnecessary. ..

In order to improve the display brightness, it is preferable that the reflective electrode 22 is large. Therefore, in FIG. 12 and FIG. 13, the end portion of the reflective electrode 22 is also formed on the source bus line 23 via the organic insulating film 20.
It is larger than the reflective electrode 9 shown by 1.

However, since the organic insulating film 20 has unevenness, the concave portion becomes deep, and when the bottom 20b of the concave portion comes into contact with the source bus line 23 to cause etching failure, insulation by the organic insulating film 20 will occur. However, there is a problem in that insulation failure occurs between the reflective electrode 22 formed on the organic insulating film 20 and the source bus line 23.

Further, since the organic insulating film 20 having the convex portion 20a is formed on the entire surface of the substrate 12, when the reflective electrode 22 is patterned, the convex portion 20a causes unevenness at the end of the reflective electrode 22, and the reflective electrode 22 is formed. There is a problem that 22 patterning failure occurs.

Further, since the convex portion 20a has only a circular planar shape, the convex portion 20a occupies a large proportion, so that specular reflection increases and a reflection type liquid crystal display device having a bright reflection characteristic due to scattered light is provided. There is a problem that it cannot be realized.

An object of the present invention is to solve the above-mentioned problems and to provide a reflective liquid crystal display device having a reflective electrode having good reflective characteristics and a method for manufacturing the same.

[0021]

According to the present invention, of a pair of transparent substrates opposed to each other with a liquid crystal layer interposed therebetween, an insulating film having irregularities is applied to one of the substrates, and an insulating film having irregularities is applied thereon. A plurality of reflective electrodes, which are display picture elements that reflect the incident light from the other substrate side, are formed on the liquid crystal layer side of the other substrate, and a common electrode having translucency is formed over almost the entire surface. In the reflective liquid crystal display device, the cross-sectional shape of the convex portion is a fine donut shape or a mixture of a circular shape and a donut shape, and the arrangement is irregular. is there.

Further, according to the present invention, of a pair of transparent substrates opposed to each other with a liquid crystal layer interposed therebetween, an insulating film having irregularities is applied on one liquid crystal layer side, and the other substrate side is applied thereon. A reflective liquid crystal formed by forming a plurality of reflective electrodes which are display picture elements for reflecting incident light from, and forming a transparent common electrode on the liquid crystal layer side of the other substrate over substantially the entire surface. In the method for manufacturing a display device, an organic insulating film is uniformly applied on the transparent substrate on the side of the reflective electrode, a photoresist layer is applied thereon, and a transparent doughnut-shaped or a mixture of circular and donut-shaped transparent films is applied. After making holes in the photoresist by irradiating the photoresist layer with a mask in which the holes are irregularly formed and irradiating it with light, etching is performed to form irregularities in the organic insulating film, and a metal thin film is formed on it. Characterized by It is a manufacturing method of a reflection type liquid crystal display device.

[0023]

According to the invention, in the reflection type liquid crystal display device, the reflection electrode is formed by a donut shape having a fine sectional shape or a convex portion in which a circular shape and a donut shape are mixed.
The arrangement is irregular. Further, since the concavo-convex portion is formed by using the mask, its shape, especially the depth of the concave portion is constant, which does not damage the element due to insulation failure, scatters incident light, and has a bright reflection characteristic. ..

Furthermore, when the surface of the reflecting plate on which the thin film having the reflecting function is formed is the liquid crystal layer side, especially when parallax is a problem,
That is, it can be configured to be arranged at a position substantially adjacent to the liquid crystal layer.

The thin film having the reflecting function may be an insulating thin film of a notch type filter using a dielectric mirror or cholesteric liquid crystal, but may be a metal thin film. Further, in this case, the function can be imparted also as an electrode facing the electrode formed on the translucent substrate with the liquid crystal layer in between.

[0026]

EXAMPLES The present invention will be described in more detail below with reference to examples.

FIG. 1 is a sectional view of a reflection type liquid crystal display device 30 which is an embodiment of the present invention, and FIG. 2 is a plan view of a substrate 31 shown in FIG. A plurality of gate bus wirings 32 made of chromium, tantalum, or the like are provided in parallel with each other on an insulating substrate 31 made of glass or the like, and a gate electrode 33 branches from the gate bus wiring 32. The gate bus line 32 functions as a scanning line.

On the entire surface of the substrate 31 covering the gate electrode 33, silicon nitride (SiN _x ) and silicon oxide (Si
A gate insulating film 34 made of O _x ) or the like is formed. On the gate insulating film 34 above the gate electrode 33,
A semiconductor layer 35 made of amorphous silicon (hereinafter referred to as a-Si), polycrystalline silicon, CdSe, or the like is formed. Contact electrodes 41 made of a-Si or the like are formed on both ends of the semiconductor layer 35. A source electrode 36 made of titanium, molybdenum, aluminum or the like is formed on one contact electrode 41 in an overlapping manner, and titanium is formed on the other contact electrode 41 in the same manner as the source electrode 36.
Drain electrode 3 made of molybdenum, aluminum, etc.
7 are formed in an overlapping manner.

As shown in FIG. 2, the source electrode 36 is connected to the source bus line 39 which intersects the gate bus line 32 with the gate insulating film 34 interposed therebetween. The source bus line 39 functions as a signal line. The source bus line 39 is also made of the same metal as the source electrode 36. Gate electrode 33, gate insulating film 34, semiconductor layer 3
5, the source electrode 36 and the drain electrode 37 are TFTs
The TFT 40 has a function of a switching element.

Gate bus wiring 32, source bus wiring 39
An organic insulating film 42 is formed on the entire surface of the substrate 31 so as to cover the TFT 40. Reflective electrode 3 of organic insulating film 42
In a region where 8 is formed, tapered convex portions 42a and 42b having a cross section of a donut shape or a circular shape are formed at a height H, and a contact hole 43 is formed in a drain electrode 37 portion. There is. In order to reduce problems in the method of forming the organic insulating film 42, the process of forming the contact holes 43 in the organic insulating film 42, and variations in cell thickness when the liquid crystal display device 30 is formed, donut-shaped or circular convex portions 42a and 42b are formed. The height H is preferably 10 μm or less (generally, the thickness of the cell is 10 μm or less). Organic insulating film 4
A reflective electrode 38 made of aluminum, silver or the like is formed on the area where the two doughnut-shaped or circular convex portions 42a and 42b are formed, and the reflective electrode 38 is connected to the drain electrode 37 in the contact hole 43. Further, an alignment film 44 is formed thereon.

On the other substrate 45, the color filter 4
6 is formed. A magenta or green filter 46a is formed at a position of the color filter 46 facing the reflective electrode 38 of the substrate 31, and a black filter 46b is formed at a position not facing the reflective electrode 38. A transparent electrode 4 made of ITO or the like is formed on the entire surface of the color filter 46.
7. Further, an alignment film 48 is formed on it.

The substrates 31 and 45 are adhered to each other so that the reflective electrode 38 and the filter 46a are opposed to each other, and the liquid crystal 49 is injected between them to form the reflective liquid crystal display device 30.
Is completed.

FIG. 3 shows the substrate 31 having the reflective electrode 38 having the donut-shaped or circular unevenness shown in FIGS.
4A and 4B are process diagrams for explaining the forming method formed above, FIG. 4 is a sectional view for explaining the forming method shown in FIG. 3, and FIG. 5 is a plan view of the mask 51 used in step s7 of FIG.
FIG. 4 (1) shows the step s4 of FIG. 3, and FIG.
4 (3) shows the step s8 of FIG. 3, and FIG. 4 (4) shows the step s9 of FIG.

In step s1, a tantalum metal layer having a thickness of 3000 Å is formed on an insulating substrate 31 made of glass or the like by a sputtering method, and the metal layer is patterned by a photolithographic method and etching to form a gate bus wiring. 32 and the gate electrode 33 are formed. In step s2, the plasma CVD method is used to measure 4000.
A gate insulating film 34 made of silicon nitride having a thickness of Å is formed.

In step s3, the thickness of the semiconductor layer 35 is 1
A 000 Å a-Si layer and a 400 Å thick n ⁺ -type a-Si layer to be the contact layer 41 are continuously formed in this order. The formed n ⁺ type a-Si layer and a-Si layer are patterned to form the semiconductor 35 and the contact layer 4.
1 is formed. In step s4, the thickness of the substrate 31 is 2
000 Å molybdenum metal is formed by the sputtering method, and the molybdenum metal layer is patterned to form the source electrode 36, the drain electrode 37 and the source bus wiring 39, and the TFT 40 is completed. Figure 4 (1) shows
FIG. 6 is a cross-sectional view of the substrate 31 on which the TFT 40 is formed after the processing up to step s4 is completed.

In step s5, a polyimide resin (trade name: JSS-74) is formed on the entire surface of the substrate 31 on which the TFT 40 is formed.
2; manufactured by Japan Synthetic Rubber Co., Ltd.) at 1200 rpm for 2
The organic insulating film 42 is formed by spin coating for 0 seconds to form a film having a thickness of 2 μm. In step s6, the contact hole 43 is formed in the organic insulating film 42 by using the photolithography method and the dry etching method. In step s7, a photoresist 50 is applied on the organic insulating film 42, and a donut-shaped convex portion 50a and a circular convex portion 50b are formed on the photoresist 50 in the reflective electrode 38 forming region using the mask 51 shown in FIG.
And pattern. Further, in order to remove the corners of the donut-shaped and circular protrusions 50a and 50b, the temperature is 120 ° C to 2 ° C.
Heat treatment is performed in the range of 50 ° C. In this embodiment, 200
Heat treatment was performed at 30 ° C. for 30 minutes. In FIG. 4B, step s7
The sectional view of the board | substrate 31 after completion | finish of the processing up to is shown. Mask 5
In FIG. 1, donut-shaped and circular light-shielding regions 51a, which are hatched in FIG. 5, are irregularly formed in the reflection electrode 38 formation region.

In step s8, as shown in FIG. 4C, the portion of the organic insulating film 42 where the photoresist 50 is not present is etched to form a donut-shaped convex portion 4 having a height H of 1.0 μm.
2a and a circular convex portion 42b are formed. At this time, since the photoresist 50 is heat-treated and the corners of the donut-shaped and circular convex portions are removed, the donut-shaped convex portions 42a and the circular convex portions 42b are also formed with the rounded corners. The contact hole 43 and the organic insulating film 42 on the TFT 40 are protected by a photoresist 50,
No etching is done. After the etching is finished, the photoresist 50 is removed by washing with a chemical or irradiating with light.

In step s9, an aluminum layer is formed on the entire surface of the organic insulating film 42, and as shown in FIG. 4 (4), the reflective electrode 38 is formed on the donut-shaped convex portion 42a and the circular convex portion 42b. Form. The substrate 31 in this state is referred to as a substrate 52 having the reflective electrode 38. The reflective electrode 38 is T-shaped through the contact hole 43 formed in the organic insulating film 42.
It is connected to the drain electrode 37 of the FT 40.

The shape of the protrusions on the organic insulating film 42 can be controlled by the shape of the mask 51, the thickness of the photoresist 50, and the dry etching time, but another organic insulating film may be applied. .. Donut-shaped convex portion 42a
An example of the shape of the circular convex portion 42b is shown in FIG.

Through the above steps, the substrate 52 having the reflective electrode 38 was obtained. Further, in the above-described manufacturing process, the dry etching time of the organic insulating film 42 can be lengthened to obtain the substrate 31 in which the height H of each of the donut-shaped convex portion 42a and the circular convex portion 42b is 1 μm. , Height H
The substrate 31 having the reflective electrode 38 having a thickness of 1 μm.
Set to 9.

The electrode 47 formed on the other substrate 45 shown in FIG. 1 is made of, for example, ITO and has a thickness of 100.
It is 0Å. The alignment films 44 and 48 are formed by applying polyimide or the like and then baking it. Board 3
A space for enclosing the liquid crystal 49 is formed between 1 and 45 by screen-printing an adhesive sealant (not shown) mixed with a spacer of 7 μm, for example, and the liquid crystal 49 is injected by degassing the space under vacuum. It As the liquid crystal 49, for example, a guest-host liquid crystal (manufactured by Merck, trade name ZLI2327) mixed with a black dye and an optically active substance (manufactured by Merck, trade name S811) of 4.5 are used.
% Use a mixture.

FIG. 7 shows a reflection plate 70 having a reflection electrode 67.
FIG. 6 is a cross-sectional view showing a method for measuring the reflection characteristics of Reflector 70
Since the refractive index of the liquid crystal layer and the glass substrate are both substantially equal to about 1.5, the refractive index of 1.5 on the reflection plate 70 having the reflection electrode 67 is assumed.
The glass substrate 62 is brought into close contact with the ultraviolet curable adhesive resin 63, and the measuring device 61 is formed. A photomultimeter 64 for measuring the intensity of light is arranged above the glass substrate 62. The photo multimeter 64 includes a reflection plate 67.
Of the incident light 65 incident at an incident angle θ with respect to, the light is fixed in the normal direction of the reflection plate 70 so that scattered light 66 reflected by the reflective electrode 70 in the normal direction of the glass substrate 69 is detected. ..

The reflection characteristic of the reflective electrode 67 can be obtained by changing the incident angle θ of the incident light 65 incident on the measuring device 61 and measuring the scattered light 66 in the direction normal to the reflective electrode 67.

FIG. 8 is a graph showing the reflection characteristics of the reflection electrode 38 having the donut-shaped and circular convex portions shown in FIG. In FIG. 8, the reflection intensity of light incident at the incident angle θ is represented as the distance from the origin 0 in the direction of the angle θ with respect to the line of θ = 0 °. The reflection characteristics of the reflection electrode 38 are indicated by black triangles. The reflection characteristic curve indicated by a white circle is measured with respect to a standard white plate (magnesium oxide).

FIG. 9 is a graph showing the reflection characteristics of the conventional reflective electrode 22 shown in FIG. 13 in which the shape of the convex portion is only circular. Comparing the reflection characteristic of the reflective electrode 38 having a convex portion in which a circular shape and a donut shape are mixed with each other, the reflective characteristic of the former is better,
It can be seen that a bright display can be obtained.

By appropriately selecting the kind and thickness of the polyimide resin and the heat treatment temperature of the resist, the inclination angle of the irregularities can be freely controlled, and the incident angle θ of the reflection intensity can be controlled accordingly.
Can control the dependencies of. The reflection intensity can also be controlled by changing the type and film thickness of the organic insulating film applied thereon.

The magnitude of the specular reflection component can also be controlled by changing the proportion of the punched portion of the mask 51.

Further, in this embodiment, the circular shape and the donut shape are combined, but the same effect can be obtained even if the shape is only the donut shape.

The reflectance was measured by placing the above reflection type liquid crystal display device at the position of the reflection plate shown in FIG. The reflectance is explained for the incident light incident at the incident angle θ = 30 °, and by calculating the ratio of the intensity of the diffused light in the normal direction of the display device to the diffused light in the normal direction of the standard white plate. can get.

In the reflective liquid crystal display device of this embodiment, since the surface of the reflective active matrix substrate 33 on which the reflective electrode 32 is formed is located on the liquid crystal layer side, parallax is eliminated and a good display screen is obtained. Be done. Further, in this embodiment, since the reflective thin film of the reflective active matrix substrate 33 is arranged on the liquid crystal layer side, that is, at a position substantially adjacent to the liquid crystal layer, the height H of the convex portion is larger than the cell thickness. It is desirable that the angle of inclination of the convex portion is small and is gentle enough not to disturb the alignment of the liquid crystal.

Further, although the patterning of the organic insulating film is carried out by the dry etching method in this embodiment, it may be carried out by the wet etching method using an alkaline solution when the organic insulating film is a polyimide resin. Further, although the polyimide resin is used as the organic insulating film, other organic materials such as acrylic resin can be used. Further, as the substrate, a glass substrate was used in this embodiment, but Si
The same effect is exhibited by an opaque substrate such as a substrate, and in this case, there is an advantage that a circuit can be integrated on the substrate.

In the present embodiment, the phase transition type guest-host mode is taken as the display mode, but the present invention is not limited to this, and other light absorption modes such as a two-layer type guest-host mode and polymers. Light-scattering display mode such as dispersed LCD (liquid crystal display), ferroelectric LCD
It is possible to apply the reflective active matrix substrate and the manufacturing method thereof according to the present invention such as the birefringence display mode used in. Although the case where the TFT is used as the switching element has been described, other elements such as MIM (Met
It can also be applied to an active matrix substrate using an element (Al Insulator Metal) element, a diode, a varistor, or the like.

A resist (OF
The one using PR-800) has the effect of further reducing the interference light.

[0054]

As described above, according to the present invention, by using a mask having a mixture of a donut shape and a circular shape, an insulating film having a constant pattern in which the convex portions are mixed with the donut shape and a circular shape is obtained. By forming a reflective electrode on the substrate, a reflective liquid crystal display device having good reflective characteristics can be manufactured with good reproducibility.

[Brief description of drawings]

FIG. 1 is a reflection type liquid crystal display device 3 according to an embodiment of the present invention.
It is sectional drawing of 0.

FIG. 2 is a plan view of a substrate 31 shown in FIG.

3A and 3B are process diagrams illustrating a method of forming a reflective electrode 38 having donut-shaped and circular convex portions on the substrate 31 shown in FIGS. 1 and 2.

FIG. 4 is a substrate 31 for explaining the forming method shown in FIG.
FIG.

5 is a plan view of a mask 51 used in step s7 of FIG.

6A and 6B are a plan view and a cross-sectional view showing an example of the shape of the convex portion of the reflective electrode 38 formed in the step of FIG.

FIG. 7 is a cross-sectional view illustrating the principle of an apparatus that measures the reflection characteristics of a reflection electrode 67.

FIG. 8 is a graph showing the reflection characteristics of a reflective electrode having a donut shape and a circular protrusion according to the present invention.

FIG. 9 is a graph showing a reflection characteristic of a reflection electrode 22 having only circular convex portions according to a conventional technique.

FIG. 10 is a plan view of a substrate 2 of a reflective liquid crystal display device used in a conventional technique.

11 is a cross-sectional view taken along the section line XI-XI shown in FIG.

FIG. 12 is a plan view of a substrate 12 of another reflective liquid crystal display device used in the related art.

13 is a cross-sectional view taken along the section line XII-XII shown in FIG.

[Explanation of symbols]

 30 reflective liquid crystal display device 38 reflective electrode 42 organic insulating film 42a donut-shaped convex portion 42b circular convex portion 51 mask

Claims (2)

[Claims] 1. A pair of transparent substrates, which are opposed to each other with a liquid crystal layer in between, is coated with an insulating film having irregularities on one of the substrates, and the insulating film is incident on the other substrate. In a reflective liquid crystal device configured by forming a plurality of reflective electrodes that are display picture elements that reflect light, and forming a common electrode having translucency over almost the entire surface on the liquid crystal layer side on the other substrate, A reflection type liquid crystal display device, wherein the cross-sectional shape of the convex portion is a fine donut shape or a mixture of a circular shape and a donut shape, and the arrangement thereof is irregular. 2. A pair of transparent substrates, which are opposed to each other with a liquid crystal layer interposed therebetween, is coated with an insulating film having irregularities on the liquid crystal layer side on one substrate, and is incident on the other substrate side from the other substrate. In a reflective liquid crystal display device, a plurality of reflective electrodes, which are display picture elements that reflect light, are formed, and a common electrode having a light-transmitting property is formed over substantially the entire surface of the other substrate on the liquid crystal layer side. In the manufacturing method, an organic insulating film is uniformly applied on the transparent substrate on the side of the reflective electrode, and a photoresist layer is applied on the organic insulating film, and a fine donut shape or a mixed hole of circular shape and donut shape is formed. It features that a regularly formed mask is applied to the photoresist layer to irradiate it with light to make holes in the photoresist, and then etching is performed to form irregularities in the organic insulating film, and a metal thin film is formed thereon. Reflective liquid crystal Method of manufacturing shows apparatus.