JP2001004984A - Substrate for liquid crystal display device and liquid crystal device and electronic appliance using the substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for a liquid crystal device having good reflection characteristics by forming a rough pattern with random distribution of pitch and height on the substrate for a liquid crystal device. SOLUTION: A specified rough pattern is formed on the surface of a substrate, with random distribution of height in the range from 0.001 μ to the thickness of the liquid crystal layer of the liquid crystal device using this substrate, and with random distribution of pitch from 0.001 μm to the length of the short side line of the pixel electrode of the liquid crystal device using this substrate. The figure shows an enlarged part of the chart obtained by measuring the profile of the rough pattern formed on the substrate for a liquid crystal device, and the profile shows random height and pitch of the rough pattern. Since the rough pattern is random both in depth and pitch, the substrate acts as a reflection plate which has good reflection characteristics and which does not cause coloring by the difference in the optical path of reflected light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for a liquid crystal device, and more particularly to a substrate for a liquid crystal device having an uneven surface. Further, the present invention relates to a liquid crystal device using the same, and an electronic apparatus including the liquid crystal device.

[0002]

2. Description of the Related Art With the expansion of the portable information equipment market, a liquid crystal device has become the mainstream as a display device which satisfies the condition of low power consumption. The use of reflection type liquid crystal devices that utilize incident light from a light source as a light source is progressing. 2. Description of the Related Art Conventionally, a commercially available reflector or a reflector integrated with a polarizing plate has been attached to the outer surface of a liquid crystal cell on the side opposite to the observation side to manufacture a reflective liquid crystal device. Examples of commercially available reflectors include M-type and S-type manufactured by Nitto Denko Corporation, and polarizing plate-integrated reflectors using these are also on the market.

In recent years, such a reflective liquid crystal device has been required to be brighter and, in some cases, to be colored. As an example of realizing a brighter and higher quality display, a method of providing a reflector on the substrate surface is introduced (Tohru Koizumi and Tatsuo Uchida Proceedi
ngs of the SID, Vol.29, p157, 1988). In this document,
In order to obtain a bright display, by controlling the formation of irregularities on the reflector, a reflector having optimal reflection characteristics is produced by polishing the surface of the glass substrate with an abrasive, and then using hydrogen fluoride. It describes a reflector in which the shape of the uneven portion is controlled by changing the etching time with an acid, and an Ag metal thin film is formed thereon.

Japanese Patent No. 210698 discloses that an oxide film is formed on a glass substrate by a sputtering method, and is etched with a hydrofluoric acid-based etchant to control the shape of the uneven portion. Describes a reflector having an Ag metal thin film formed thereon.

Further, Japanese Patent Application Laid-Open No. 6-75238 discloses that a photosensitive resin is exposed and developed through a light-shielding mask having irregularly arranged through-holes, and is then subjected to heat treatment. Describes a reflector having an Al metal thin film formed thereon.

These documents describe a method of forming a reflector by forming a thin film having a light reflecting function on the irregularities formed on the substrate, and restricting the irregularities on the substrate to a predetermined range. By doing so, the objective was to control the reflected light intensity scattered at a predetermined angle with respect to incident light from a wide angle.

[0007]

However, in the method described in the above-mentioned document (Proceedings of the SID, Vol. 29, p. 157, 1988), since the etching process is performed based on the unevenness caused by the abrasive, the pitch of the unevenness in the horizontal direction is increased. Can be made random, but in the height direction, the proportion of unevenness having the same height due to the size of the abrasive increases.

In the method described in Japanese Patent No. 210698, the average pitch of the irregularities is described, but the distribution of the three-dimensional irregularities is not described. Even in the part that describes the conditions for providing good reflection characteristics, the height of the convex part has only a specific value, so the pitch in the horizontal direction is random, but it is about the same in the height direction Is arranged.

Further, in the method described in JP-A-6-75238, a fine convex shape is formed by a step of patterning a photosensitive resin by a photolithography method. In the height direction, convex portions having the same height due to the thickness of the applied photosensitive resin are arranged.

As described above, when the value of the height in the height direction of the unevenness is almost constant, the light reflected by the reflector using the uneven surface has an optical path difference as shown in FIG. Unnecessary coloration occurs due to the resulting interference, which causes deterioration in display quality of a liquid crystal device using the same.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to make the distribution of irregularities formed on a substrate for a liquid crystal device random with respect to pitch and height, and to quantitatively define the surface layer shape. It is another object of the present invention to provide a liquid crystal device substrate in which a reflector using the same has good reflection characteristics.

[0012]

Means taken by the present invention to solve the above problems are as follows.

The substrate for a liquid crystal device of the present invention is a substrate for a liquid crystal device in which predetermined irregularities are formed on the surface of the substrate. Random, pitch 0.00 within the thickness range
It is characterized by being provided randomly in a range of 1 to less than the length of a short side of a pixel electrode of a liquid crystal device using the same.

The upper limit of the height and pitch of the unevenness in the present invention is not more than the thickness of the liquid crystal layer of the liquid crystal device (cell gap of the liquid crystal cell) and the length of the short side of the pixel electrode of the liquid crystal device, respectively. The cell gap of a generally used liquid crystal cell is around 5 μm, the pixel pitch is 80 to 300 μm,
By controlling the height of the unevenness and the upper limit of the pitch below this, it is possible to form a reflector having an uneven shape on the liquid crystal layer side of the liquid crystal cell. In a practical liquid crystal cell used for a liquid crystal device, the height and pitch of the unevenness are desirably 3 μm or less and 80 μm or less, respectively.

Further, in the liquid crystal device substrate according to the present invention, in a liquid crystal device substrate having predetermined irregularities formed on the substrate surface, the constituent components of the raw material substrate are etched for each minute portion, and the constituent components of the raw material substrate are formed. Irregularities are formed only by the irregularities, and the rough irregularities are random in a range of a height of 0.001 μm or less and a thickness of the liquid crystal layer of the liquid crystal device using the same or less, and a pitch of 0.001 μm or less of the liquid crystal device using the same It is characterized by being provided randomly in a range not more than the length of the short side of the pixel electrode.

According to the present invention, since the unevenness is formed only by the constituent components of the raw material substrate, it is possible to directly carry out the manufacturing process of the liquid crystal device substrate that can flow with the raw material substrate.

In the substrate for a liquid crystal device according to the present invention, the unevenness may be:
Ry (JIS) (maximum height) is 0.2 ~
3 μm, Ra (arithmetic average roughness: center line average) is 0.0
2 to 0.3 μm, Rz (JIS) (ten-point average roughness) is 0.1
2.5 m, Sm (1%: JIS) (average wavelength of unevenness) is 4
It is characterized by being quantitatively defined in the range of ６０60 μm.

According to this method, the unevenness formed randomly in both the height and the pitch can be quantitatively defined by handling the surface roughness analysis, so that the characteristics optimized for various liquid crystal devices can be obtained. A liquid crystal device substrate serving as a reflection plate can be obtained. By quantitatively defining the surface layer shape of the unevenness, it becomes possible to provide a liquid crystal substrate serving as a reflector having good characteristics with good reproducibility, and it can be used as a control value in manufacturing.

In the substrate for a liquid crystal device according to the present invention, the irregularities have a surface layer shape of Ry (JIS) (maximum height) of 1.
5 to 2.0 μm, Ra (arithmetic mean roughness: center line mean)
Is 0.15 to 0.3 µm, Rz (JIS) (10-point average roughness)
Is 1.3 to 1.8 μm, and Sm (1%: JIS) (average wavelength of unevenness) is quantitatively defined in the range of 15 to 25 μm.

In the substrate for a liquid crystal device according to the present invention, the irregularities have a surface layer shape of Ry (JIS) (maximum height) of 0.1 mm.
7 to 1.2 μm, Ra (arithmetic mean roughness: center line mean)
Is 0.1 to 0.2 μm, Rz (JIS) (ten point average roughness) is 0.5 to 1.0 μm, and Sm (1%: JIS) (average wavelength of unevenness) is 35 to 50 μm. It is characterized by the fact that it is specified.

Further, in the substrate for a liquid crystal device of the present invention, the irregularities have a surface shape of Ry (JIS) (maximum height) of 0.1 mm.
6 to 1.2 μm, Ra (arithmetic average roughness: center line average)
Is 0.05 to 0.15 μm, Rz (JIS) (ten point average roughness) is 0.5 to 1.0 μm, and Sm (1%: JIS) (average wavelength of irregularities) is 15 to 25 μm. It is characterized by the fact that it is specified.

In the substrate for a liquid crystal device according to the present invention, the irregularities have a surface layer shape of Ry (JIS) (maximum height) of 0.1 mm.
4-1.0 μm, Ra (arithmetic mean roughness: centerline mean value)
Is 0.04 to 0.10 μm, Rz (JIS) (ten point average roughness) is 0.3 to 0.8 μm, and Sm (1%: JIS) (average wavelength of unevenness) is 8 to 15 μm. It is characterized by the fact that it is specified.

In the substrate for a liquid crystal device according to the present invention, the irregularities have a surface shape of Ry (JIS) (maximum height) of 0.1 mm.
8-1.5 μm, Ra (arithmetic mean roughness: center line mean)
Is 0.05 to 0.15 μm, Rz (JIS) (ten point average roughness) is 0.7 to 1.3 μm, and Sm (1%: JIS) (average wavelength of unevenness) is 8 to 15 μm. It is characterized by the fact that it is specified.

According to the liquid crystal device of the present invention, a liquid crystal layer is sandwiched between a pair of insulating substrates, and the liquid crystal device substrate according to any one of the above is used as one of the insulating substrates. Features.

According to another aspect of the invention, there is provided an electronic apparatus including the liquid crystal device.

According to this, it is possible to realize an electronic apparatus capable of performing high-contrast, bright, and excellent reflection-type display.

[0027]

The thickness of the liquid crystal layer in the liquid crystal mode which is generally used is 10 μm or less. Therefore, even when a glass substrate provided with a reflector having projections and depressions on the liquid crystal layer side of a liquid crystal device is used, the height of the projections and depressions is not reduced. It is less than the thickness of the liquid crystal layer. More desirably, the thickness of the liquid crystal layer of the reflection type liquid crystal device is about 5 μm. Therefore, in the liquid crystal device substrate of the present invention, the height of the unevenness provided on the liquid crystal layer side of the substrate is 3 μm or less. The pitch of the unevenness is preferably equal to or less than the width of the short side of the pixel electrode of a generally used liquid crystal device, and is preferably equal to or less than 80 μm in consideration of the optimal scattering characteristics associated with the height of the unevenness. Of course, in the case where a reflector having an uneven shape is formed on the surface on the opposite side of the liquid crystal layer, the thickness of the liquid crystal layer of the actual liquid crystal device is not limited. It is preferable that the concavo-convex shape be in a range defined by this means, depending on the combination condition of the concavo-convex height corresponding to the concavo-convex pitch to be provided.

A metal layer is formed on the unevenness employed here to form a reflector, and the height of the unevenness is 3 μm or less.
In order to cope with the order of several to several times the wavelength of visible light, if unevenness is formed by peaks and valleys having the same height, the reflected light may be colored by an optical path difference depending on the reflection angle. Therefore, by randomizing not only the pitch of the unevenness but also the distribution of the unevenness in the height direction, it is possible to prevent unnecessary coloring from occurring due to interference caused by an optical path difference, and to prevent a predetermined amount of incident light from the outside. And a reflection plate having good characteristics without coloring due to differences in the incident angle of external light and the observation angle of reflected light can be obtained.

Further, if the irregularities on the glass substrate are formed only by the constituent components of the raw material substrate, the manufacturing process of the liquid crystal device substrate that can flow with the raw material substrate can be performed as it is. For example, it has good resistance to heat treatment exposed to a high temperature of 200 ° C. or more and treatment with a highly soluble organic solvent.
It is also possible to form an element for driving an active matrix such as an FD.

Furthermore, it is necessary to control the shape of the concavities and convexities so that the reflection characteristics are optimal for the liquid crystal mode to be used. Since the height and pitch of the concavities and convexities are formed at random, the handling is managed by quantitative data. It is desirable.

In the present invention, JIS B0601-199
According to the surface roughness analysis method and display method according to 4 standards,
Ry (JIS) (maximum height), Ra (arithmetic average roughness: center line average), Rz (JIS) (ten-point average roughness), Sm (1%: JIS) By quantitatively defining the average wavelength), it is possible to provide a concave-convex shape having optimum reflection characteristics for each liquid crystal mode with good reproducibility. Of course, by adopting it as a quality control item at the manufacturing site, it also becomes useful information on the inspection process.

In general, in a liquid crystal device employing an STN (super twisted nematic) liquid crystal mode, the viewing angle at which good display quality can be provided with a high contrast ratio is limited to a relatively narrow angle, and visibility is low. Since there is no need to scatter the reflected light to a bad angle,
By narrowing the reflected light to an angle having good visibility and defining the surface roughness so as to form a reflective plate having strong directivity, a liquid crystal device which is extremely bright in practice and has no coloring of the reflected light can be obtained. In the STN liquid crystal mode in which the thickness unevenness of the liquid crystal layer significantly lowers the display quality, the Ry value and the Rz value are suppressed as small as possible, and the Sm value is reduced accordingly, thereby suppressing the thickness unevenness of the liquid crystal layer due to unevenness. Required scattering characteristics. In the case of the STN liquid crystal mode, a reflector having strong directivity can be provided, so that it is desirable to make the Ry value and the Rz value relatively smaller than the Sm value, thereby suppressing thickness unevenness due to unevenness. Also, Ra
By reducing the value, unevenness in the thickness of the liquid crystal layer corresponding to in-plane undulation can be suppressed.

On the other hand, a liquid crystal device employing a TN (twisted nematic) liquid crystal mode, a TN mode using a combined λ / 4 plate, and a SH (super homeotropic) liquid crystal mode has a relatively wide viewing angle characteristic. For,
By defining the surface roughness so that the scattering characteristics are optimal for each liquid crystal mode, a bright liquid crystal device that uses external light effectively and has no coloring of reflected light can be obtained. Here, by using one or both of the method of increasing the Rz value and the method of decreasing the Sm value, it is possible to realize a reflector having a high degree of scattering. In these liquid crystal modes, the display quality is not significantly reduced due to the uneven thickness of the liquid crystal layer as compared with the STN liquid crystal mode, but it is preferable to use a method of reducing the Sm value.

In the liquid crystal device of the present invention, the irregularities formed randomly in both height and pitch are quantitatively defined by analytical treatment of surface roughness, and are optimized for various liquid crystal devices. Since the substrate for a liquid crystal device serving as the reflection plate can be used, it is possible to provide a liquid crystal device that is bright and has no coloring of reflected light.

Further, by using this liquid crystal device, it is possible to provide an electronic apparatus having a liquid crystal device which has excellent visibility and high display quality.

[0036]

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

(First Embodiment) FIG. 1 is an enlarged view of a part of a chart obtained by measuring a profile of an uneven shape formed on a substrate for a liquid crystal device according to the present invention. Height of unevenness,
Both pitches are random.

The substrate for a liquid crystal device of this embodiment is shown in FIG.
It was created by the steps shown in (a) to (e). FIG.
(A) As shown in FIG.
(Trade name: PC-339H, manufactured by JSR) to a thickness of 0.8 μm by a spin coating method.
The pattern of the light-shielding portion is left by a photolithography method using a photomask in which light-shielding patterns of 0 μm and φ4 μm are randomly arranged, and 130 ° C. on a hot plate.
Then, heating was performed for 3 minutes to form an uneven shape having three levels of height and pitch as shown in FIG. 2 (b). Subsequently, after post-baking at 200 ° C. for 30 minutes,
A layer of the positive photosensitive resin 5 was formed to a thickness of 0.5 μm, and the light-shielding mask was shifted by 2 μm and exposed.
As shown in (c), the pattern shape was such that each of the concavities and convexities was randomly stacked. 130 on hot plate again
Heating was carried out at a temperature of 3 ° C. for 3 minutes to obtain random irregularities in both height and pitch as shown in FIG.

When the irregularities on the liquid crystal device substrate obtained here were measured using a surface roughness meter, Ry (JIS) = 0.
75 μm, Ra = 0.09 μm, Rz (JIS) = 0.70
μm, Sm (1%: JIS) = 17 μm. JI for measurement
The measurement mode specified in SB0601-1994 was used. As for the Sm value, the dead zone was set to 1% of the Ry value, and was designated as Sm (1%: JIS).

Subsequently, as shown in FIG. 2E, a 200 nm-thick metal layer 12 containing aluminum as a main component was formed on the substrate having the irregularities formed thereon to form a reflector. The reflector is not limited to a metal layer mainly containing aluminum, and a metal layer mainly containing silver, chromium, nickel, or the like can be used.

The reflection characteristics of the obtained reflector were measured by the measuring system shown in FIG. The metal layer 12 on the substrate 1 on which the concavo-convex portions 11 are formed is used as a reflection surface, and in order to measure with the same configuration as the liquid crystal device, a 0.7 mm thick glass of the same material as the liquid crystal 13 and the substrate 1 is formed on the metal layer 12. The measurement was performed with the substrates 14 stacked. Incident light 15 irradiated at an angle of 25 degrees from the normal direction of the substrate is reflected by the metal layer 12 as a reflector. Angle θ from the normal direction of photomultimeter 16
8 by measuring the intensity of the scattered light while changing
As shown in FIG. The reflectivity is higher in the range of about ± 25 degrees than the S-type characteristic 17 of the commercially available externally-applied reflector used for comparison, and is characteristically the same as the M-type characteristic 18 of the commercially available externally-applied reflector. Equal or better characteristics were obtained.

Since the uneven structure obtained here was random in both depth and pitch, a reflector having good reflection characteristics without coloring due to the optical path difference of the reflected light was obtained.

(Second Embodiment) FIGS. 3 (a) to 3 (f) are views showing a process for forming a concavo-convex shape of a liquid crystal device substrate according to the present invention. Here, an aluminosilicate glass substrate was used, and the irregularities were formed only by the components of the glass substrate. FIG. 3A is a schematic sectional view of the mesh structure of the glass substrate 1. In the aluminosilicate glass, a copolymer of silicic acid and aluminum oxide forms a network forming body, and forms the network structure 2.

First, a 5 wt% aqueous hydrofluoric acid solution at 25 ° C.
The glass substrate 1 was washed for 5 seconds, and the surface of the substrate 1 was uniformly etched to expose a clean surface. Next, the substrate 1 was immersed in a 30% by weight aqueous solution of hydrofluoric acid in a supersaturated solution of aluminum oxide and magnesium oxide, and treated at 25 ° C. for 50 seconds. In this treatment, as shown in FIG. 3 (b), a portion where the aluminum oxide of the network structure 2 made of a copolymer of silicic acid and aluminum oxide is localized, and magnesium oxide is localized as a network modifier. At the same time, the same component is precipitated from the supersaturated solution to form a fine network structure 10 and, at the same time, a region on the surface of the glass substrate 1 where the component not supersaturated and dissolved in the processing liquid is exposed, Irregularities 11 were formed along the fine network structure 10 by being attacked by hydrofluoric acid.
The unevenness was randomly formed with a step of about 2.2 μm and the pitch of the unevenness was randomly formed with a pitch of 10 μm.

Subsequently, the mixture was treated at 25 ° C. for 30 seconds with a chemical solution obtained by mixing hydrofluoric acid (50 wt%) and an aqueous solution of ammonium fluoride (40 wt%) at a weight ratio of 1: 3, and as shown in FIG. As shown in the figure, the uneven portion 11 on the surface of the substrate 1 is uniformly etched to remove the fine network structure 10, and as shown in FIG. 3D, the fine convex portion on the uneven portion 11 is melted. As shown in the profile measurement chart shown in FIG. 4 (a), a smooth uneven surface with random height and pitch was formed.

When the irregularities on the liquid crystal device substrate obtained here were measured using a surface roughness meter, Ry (JIS) = 1.
75 μm, Ra = 0.24 μm, Rz (JIS) = 1.57
μm, Sm (1%: JIS) = 22 μm.

Subsequently, as shown in FIG. 3E, a metal layer 12 containing aluminum as a main component was formed to a thickness of 200 nm on the substrate 1 on which the uneven portions 11 were formed, thereby forming a reflector. The reflector is not limited to a metal layer mainly containing aluminum, and a metal layer mainly containing silver, chromium, nickel, or the like can be used.

When the reflection characteristics of the obtained reflector were measured by the same method as in the first embodiment using the measurement system shown in FIG. 7, the characteristics as shown in the reflection characteristics 21 of FIG. 8 were obtained. . A reflector having a wide scattering degree and good viewing angle characteristics equivalent to the S-type characteristic 17 of the commercially available externally attached reflector used for comparison was obtained. The uneven structure obtained here has a depth,
Since both pitches were random, a reflector having good reflection characteristics without coloring due to the optical path difference of the reflected light was obtained.

A chemical solution shown in FIG. 3 (d) in which hydrofluoric acid (50% by weight) and an aqueous solution of ammonium fluoride (40% by weight) were mixed at a weight ratio of 1: 3. By performing a process of uniformly etching No. 11 at 25 ° C. for 50 seconds, the protrusions are dissolved, and the fine unevenness is absorbed by one smooth uneven surface.
As shown in the profile measurement chart shown in (b), the height of the unevenness could be made smaller and the pitch could be made larger.

When the irregularities on the obtained liquid crystal device substrate were measured using a surface roughness meter, Ry (JIS) = 0.
98 μm, Ra = 0.13 μm, Rz (JIS) = 0.80
μm, Sm (1%: JIS) = 42 μm.

On this substrate, a metal layer mainly composed of aluminum was formed to a thickness of 200 nm to form a reflector, and the reflection characteristics of the obtained reflector were measured by the measuring system shown in FIG. 7 in the same manner as in the first embodiment. The reflection characteristic 23 shown in FIG.
It was a highly directional reflector capable of increasing the reflectance within ± 10 degrees as shown in FIG. Since the uneven structure obtained here was random in both depth and pitch, a reflector having good reflection characteristics without coloring due to the optical path difference of the reflected light was obtained.

(Third Embodiment) A substrate for a liquid crystal device according to the present embodiment will be described with reference to FIGS.
In this embodiment, a supersaturated aluminum oxide and barium oxide solution of a 25 wt% aqueous hydrofluoric acid solution was used as the processing liquid in the manufacturing process of FIG. The other steps are the same as in the second embodiment, and thus will not be described here.

When the irregularities on the obtained liquid crystal device substrate were measured using a surface roughness meter, Ry (JIS) = 0.
6 μm, Ra = 0.08 μm, Rz (JIS) = 0.45 μm
m and Sm (1%: JIS) = 11 μm.

On this substrate, a metal layer mainly composed of aluminum was formed to a thickness of 200 nm to form a reflector, and the reflection characteristics of the obtained reflector were measured by the measuring system shown in FIG. 7 in the same manner as in the first embodiment. As a result, the reflection characteristic 20 shown in FIG.
The characteristics shown in FIG. Within a range of ± 20 degrees from the characteristic 18 of the M type of the commercially available externally attached reflector used for comparison, the reflectivity was higher, and a brighter reflector having good characteristics was obtained. The reflector is not limited to a metal layer mainly containing aluminum, and a metal layer mainly containing silver, chromium, nickel, or the like can be used. Since the uneven structure obtained here was random in both depth and pitch, a reflector having good reflection characteristics without coloring due to the optical path difference of the reflected light was obtained.

The substrate for a liquid crystal device of the present embodiment is most suitable for a liquid crystal device employing the STN liquid crystal mode, and the Ry value and the Rz value are suppressed as small as possible, and the Sm value is correspondingly reduced, so that unevenness is obtained. It provides the necessary scattering characteristics while suppressing the accompanying thickness unevenness of the liquid crystal layer. In the case of the STN liquid crystal mode, the viewing angle that can provide good display quality with a high contrast ratio is limited to a relatively narrow angle, and a highly directional reflector can be used.
The Ry value and the Rz value are relatively smaller than the values, thereby suppressing thickness unevenness due to unevenness. Also, Ra
By reducing the value, the unevenness of the thickness of the liquid crystal layer corresponding to the in-plane undulation is suppressed, and a liquid crystal device with high display quality can be provided.

The liquid crystal device substrate of the present embodiment is most suitable for a liquid crystal device employing the STN liquid crystal mode.
The present invention can be applied to a liquid crystal device adopting an N (twisted nematic) liquid crystal mode, a TN mode using a λ / 4 plate together, or an SH (super homeotropic) liquid crystal mode.

(Fourth Embodiment) A substrate for a liquid crystal device according to the present embodiment will be described with reference to FIGS.
In the present embodiment, a supersaturated solution of a 30 wt% hydrofluoric acid aqueous solution of aluminum oxide and barium oxide was used as the treatment liquid in the manufacturing process of FIG. The other steps are the same as in the second embodiment, and thus will not be described here.

When the irregularities on the obtained liquid crystal device substrate were measured using a surface roughness meter, Ry (JIS) = 0.
95 μm, Ra = 0.12 μm, Rz (JIS) = 0.85
μm, Sm (1%: JIS) = 11 μm.

On this substrate, a metal layer mainly composed of aluminum was formed to a thickness of 200 nm to form a reflector, and the reflection characteristics of the obtained reflector were measured by the measuring system shown in FIG. 7 in the same manner as in the first embodiment. As a result, the reflection characteristics 22 shown in FIG.
The characteristics shown in FIG. A reflector having a relatively large degree of scattering and a good viewing angle characteristic, which is close to the M-type characteristic 18 of the commercially available externally attached reflector used for comparison, was obtained. The reflector is not limited to a metal layer mainly containing aluminum, and a metal layer mainly containing silver, chromium, nickel, or the like can be used. Since the uneven structure obtained here was random in both depth and pitch, a reflector having good reflection characteristics without coloring due to the optical path difference of the reflected light was obtained.

The substrate for a liquid crystal device of the present embodiment has a relatively wide viewing angle characteristic employing a TN (twisted nematic) liquid crystal mode, a TN mode using a λ / 4 plate, and an SH (super homeotropic) liquid crystal mode. It is suitable for a liquid crystal device. Here, a wide degree of scattering is obtained by reducing the Sm value without increasing the Rz value, which is suitable for a mode in which display quality is slightly reduced due to unevenness in thickness of the liquid crystal layer. In addition, by forming a colored layer on the reflective plate and forming a color filter substrate integrated with the reflective plate, the unevenness is flattened by the coloring layer and the flattening layer which also serves as a protective layer,
The present invention can also be used for a liquid crystal device employing an STN liquid crystal mode in which unevenness leads to display unevenness.

In this embodiment, a treatment solution in which aluminum oxide and barium oxide are supersaturated in a 30 wt% aqueous hydrofluoric acid solution is used. However, the concentration of hydrofluoric acid and the composition of the aluminosilicate glass which is supersaturated and dissolved are used. By changing the selection of components, desired Ry, Ra, Rz, and Sm values can be obtained. Although aluminosilicate glass was used here as the glass substrate, other glasses, such as borosilicate glass and soda lime glass, can be used by changing the mixing ratio of the chemical solution. It is possible to obtain a substrate for a liquid crystal device having a concavo-convex shape having the above surface roughness.

FIG. 5A is an optical microscope photograph showing an example of a state in which the concave and convex portions 11 are formed along the fine network structure 10 in FIG. 3B, and FIG. 3
It is an optical microscope photograph which shows an example of the state which processed to the state of (d) and formed the smooth uneven surface. FIG. 6 is a photograph taken by an electron microscope of the liquid crystal device substrate of the present embodiment, which has been processed to the state shown in FIG. In the state of FIG. 6, it can be clearly seen that parabolic concave surfaces having various depths and sizes are arranged.

(Fifth Embodiment) FIG. 10 is a schematic sectional view of a liquid crystal device using a substrate for a liquid crystal device having an uneven shape according to a third embodiment of the present invention.

In this embodiment, two transparent substrates 100
1 and 1003, the liquid crystal layer 1008 has a frame-like sealing material 1
A liquid crystal cell sealed by 009 is formed.
The liquid crystal layer 1008 is made of a nematic liquid crystal having a predetermined twist angle. On the inner surface of the upper transparent substrate 1003, a light-shielding layer 1013, a colored layer 1004, and a protective layer 1006 also serving as a flattening film are sequentially formed.
In 04, for example, three colored layers of R (red), G (green), and B (blue) are arranged in a predetermined pattern. A plurality of stripe-shaped transparent electrodes 1010 are formed on the protective layer 1006 also serving as a flattening film via an adhesion improving layer 1005 by ITO or the like, and an alignment film 1012 is formed on the surface of the transparent electrode 1010. A rubbing process is performed in a predetermined direction.

On the other hand, the unevenness 10 of the lower transparent substrate 1001
A plurality of metal layers 1002 serving as reflectors made of, for example, Al are arranged as stripe-shaped electrodes on the inner surface on which the transparent electrodes 1010 are formed so as to intersect the transparent electrodes 1010. When the normally black mode is used as the liquid crystal mode, the black region is always displayed outside the pixel region where the liquid crystal is not driven. Therefore, the light-shielding layer 1013 may be omitted in order to reduce the cost or substantially improve the aperture ratio. It is possible. Also,
In the case of an active matrix type device including a TFD element and a TFT element, the metal layer 1002 is formed in, for example, a rectangular shape, and is connected to wiring via the active element. However, in the case of an apparatus having a TFT element, patterning of the transparent electrode 1010 is not necessary. Metal layer 100
Reference numeral 2 denotes a reflection surface that reflects light incident from the transparent substrate 1003 side.

On the outer surface of the upper transparent substrate 1003, in order from the transparent substrate 1003 side, the retardation plate 1014 and the polarizing plate 1
015 are arranged.

The reflection type display will be described. Fig. 1
After passing through the polarizing plate 1015 and the retardation plate 1014 at 0, respectively, and passing through the coloring layer 1004 and the liquid crystal layer 1008,
The light is reflected by the reflection plate 1002 and is again reflected by the polarizing plate 1015.
Is emitted from. At this time, the bright state, the dark state, and the intermediate brightness can be controlled by the voltage applied to the liquid crystal layer 1008.

According to the configuration of the present embodiment as described above, a bright, high-contrast reflective color liquid crystal device without double reflection or display bleeding can be realized.

(Sixth Embodiment) FIG. 11 is a schematic sectional view of a liquid crystal device using a substrate for a liquid crystal device having an uneven shape according to a fourth embodiment of the present invention.

The reflection type liquid crystal device can display a very bright image in a place where sufficient external light exists, but has a drawback that if the external light is insufficient, the display becomes difficult to see.

In this embodiment, by providing an opening for each pixel electrode, a transflective plate having a reflectance and a transmittance defined by the ratio of the opening to the pixel area is formed. Where light exists, reflective display is used, and where external light is insufficient, an auxiliary light source is used to perform transmissive display. The shape of the opening is arbitrary.

In this embodiment, two transparent substrates 110
1 and 1103, the liquid crystal layer 1108 is a frame-shaped sealing material 1
A liquid crystal cell sealed by 109 is formed.
The liquid crystal layer 1108 is composed of a nematic liquid crystal having a predetermined twist angle. A plurality of stripe-shaped transparent electrodes 1110 are formed on the inner surface of the upper transparent substrate 1103 by IT.
An alignment film 1112 is formed on the surface of the transparent electrode 1110 and is rubbed in a predetermined direction.

On the other hand, the unevenness 11 of the lower transparent substrate 1101
A metal layer 1102 serving as a reflector made of, for example, Al, a coloring layer 1104, and a protective layer 1106 also serving as a flattening film are sequentially formed on the inner surface on which the 20 is formed. R (red), G (green), and B (blue) colored layers are arranged in a predetermined pattern.
The region where the three colored layers of G and B are laminated is the light shielding layer 111.
It is 3. The light-shielding layer 1113 may be formed by a method separately provided with resin black or multilayer chromium, in addition to the lamination of the coloring layers. A plurality of stripe-shaped transparent electrodes 1107 formed on a protective layer 1106 also serving as a flattening film via an adhesion improving layer 1105 are arranged so as to intersect the transparent electrodes 1110. In the case of an active matrix type device including a TFD element and a TFT element, each transparent electrode 1110 is formed in, for example, a rectangular shape, and is connected to a wiring via the active element. However, in the case of an apparatus having a TFT element, patterning of the transparent electrode 1107 is not necessary. The reflecting plate 1102 is a transparent substrate 1103
This is a reflection surface that reflects light incident from the side of.

On the outer surface of the upper transparent substrate 1103, in order from the transparent substrate 1103 side, the retardation plate 1114 and the polarizing plate 1
115 are arranged. Also, under the liquid crystal cell,
A retardation plate 1116 is arranged behind the transparent substrate 1101, and a polarizing plate 1117 is arranged behind the retardation plate 1116. A backlight having a fluorescent tube 1118 that emits white light and a light guide plate 1119 having an incident end face along the fluorescent tube 1118 is disposed below the polarizing plate 1117. The light guide plate 1119 is a transparent body such as an acrylic resin plate on which a rough surface for scattering is formed on the entire back surface or a printed layer for scattering is formed, and receives light from a fluorescent tube 1118 as a light source at an end surface. , And emits substantially uniform light from the upper surface of FIG. Other backlights include LEDs (light emitting diodes) and EL
(Electroluminescence) or the like can be used.

The reflection type display will be described. Fig. 1
1, after passing through the polarizing plate 1115 and the retardation plate 1114, respectively, and passing through the liquid crystal layer 1108 and the coloring layer 1104,
The light is reflected by the metal layer 1102 serving as a reflecting plate, and is emitted again from the polarizing plate 1115. At this time, the liquid crystal layer 110
The bright state, the dark state, and the intermediate brightness can be controlled by the voltage applied to 8.

Next, the transmission type display will be described. The light from the backlight is applied to the polarizing plate 1117 and the retardation plate 111.
6, and is introduced into the coloring layer 1104 and the liquid crystal layer 1108 through the opening 1122 provided in the metal layer 1102 to be a semi-transmissive reflection plate.
After passing through No. 8, the light passes through the phase difference plate 1114. At this time,
In accordance with the voltage applied to the liquid crystal layer 1108, the polarizing plate 1115
Transmitting (bright state) and absorbing (dark state)
And an intermediate state (brightness) can be controlled.

In this embodiment, the light-shielding layer 13 is provided independently of the coloring layer, or a coloring layer optimal for the color purity at the time of transmissive display is partially provided.
It is also possible to use a substrate or the like having a color filter structure with improved values.

In this embodiment, the metal layer 1102 serving as a semi-transmissive reflector is provided with an opening 112 for each pixel electrode.
2, the transmission type display is enabled. However, by reducing the thickness of the metal layer 1102 to 15 to 20 nm, the reflectance is about 85% and the transmittance is 10%.
The same effect can be obtained by forming the front and rear transflective plates. In this case, the opening 112 of the metal layer 1102
2 becomes unnecessary. The ratio between the reflectance and the transmittance can be set to an arbitrary film thickness. In either case, since the liquid crystal layer is driven by the transparent electrodes provided on the upper and lower substrates, the reflectivity and the transmittance are determined by the metal layer serving as the transflective plate.

According to the configuration of the present embodiment as described above, it is possible to realize a color liquid crystal device capable of switching and displaying between a reflective display and a transmissive display without a double reflection or display bleeding.

(Seventh Embodiment) Three examples of the electronic apparatus of the present invention will be described.

The liquid crystal device of the present invention is suitable for portable equipment used in various environments and requiring low power consumption.

FIG. 12A shows a portable information device, in which a display section 121 is provided on the upper side of the main body, and an input section 123 is provided on the lower side. In addition, a touch panel is often provided on the front surface of the display unit. A normal touch panel has a lot of surface reflections, making it difficult to see the display. Therefore, conventionally, a transmissive liquid crystal device has often been used even though it is portable. However, since the transmissive liquid crystal device always uses the backlight, the power consumption is large and the battery life is short. Even in such a case, the liquid crystal device of the present invention can be used for a portable information device because the display is bright and vivid both in a reflective type and a transflective type.

FIG. 12B shows a portable telephone, which has a display section 124 at the upper front of the main body. Mobile phones are used in all environments, both indoors and outdoors. Especially, it is often used in cars, but the inside of cars at night is very dark.
Therefore, it is desirable that the display device used in the mobile phone is a transflective liquid crystal device capable of performing transmissive display using auxiliary light as needed, mainly reflective display with low power consumption. The liquid crystal device according to the sixth embodiment of the present invention is brighter and has a higher contrast ratio than the conventional liquid crystal device in both reflective display and transmissive display.

FIG. 12C shows a watch having a display unit 126 at the center of the main body. An important aspect in watch applications is luxury. The liquid crystal device of the present invention is not only bright and has a high contrast, but also has a small coloring due to a small change in characteristics due to the wavelength of light. Therefore, a very high-quality display can be obtained as compared with the conventional liquid crystal device.

[0085]

As described above, according to the present invention, irregularities formed at random in both height and pitch are quantitatively defined by analytical treatment of surface roughness.
It is possible to provide a liquid crystal device substrate serving as a reflector having characteristics optimized for various liquid crystal devices. Further, it is possible to configure a bright reflective color liquid crystal device without coloring of reflected light and without occurrence of double reflection or blur of display.

[Brief description of the drawings]

FIG. 1 is a chart showing a profile of an uneven shape formed on a liquid crystal device substrate according to a first embodiment of the liquid crystal device substrate according to the present invention.

FIGS. 2A to 2E are schematic views showing a manufacturing process of the liquid crystal device substrate according to the first embodiment of the present invention.

FIGS. 3A to 3E are schematic views illustrating a process for manufacturing a liquid crystal device substrate according to second to fourth embodiments of the present invention.

FIGS. 4 (a) and (b) are charts measuring the profile of an uneven shape formed on a liquid crystal device substrate according to a second embodiment of the liquid crystal device substrate according to the present invention.

5A and 5B are liquid crystal device substrates according to second to fourth embodiments of the present invention, respectively.
It is an optical microscope photograph which shows an example of the state of FIG.3 (d).

FIG. 6 is an electron micrograph of the state of FIG. 3D of the substrate for a liquid crystal device according to the fourth embodiment of the present invention.

FIG. 7 is a schematic view showing a measuring method of a reflection plate.

FIG. 8 is a diagram showing reflection characteristics of a reflector using the liquid crystal device substrate according to the first to fourth embodiments of the present invention.

FIG. 9 is a schematic diagram showing an optical path difference on a concave-convex reflecting surface.

FIG. 10 is a sectional view showing a schematic structure of a liquid crystal device according to a fifth embodiment of the present invention.

FIG. 11 is a sectional view showing a schematic structure of a liquid crystal device according to a sixth embodiment of the present invention.

FIGS. 12A and 12B are schematic views of an electronic device equipped with the liquid crystal device according to the present invention, wherein FIG. 12A shows a portable information device, FIG. 12B shows a mobile phone, and FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Glass substrate 2 ... Network-like structure by the network formation body in a glass substrate 3 ... Network modification body area | region in a glass substrate 4 ... 1st photosensitive resin 5 ... 2 layers Photosensitive resin of eyes 10 Network structure by precipitated supersaturated component 11, 1020, 1120 Uneven portion on glass substrate 12, 1002, 1102 Reflector (metal layer) 13, 1008, 1108 ..Liquid crystal layer 15 ... Incident light 16 ... Photo multimeter 17 ... Reflection characteristics of commercially available externally attached reflector S type 18 ... Reflection characteristics of commercially available externally attached reflector M type 19 ... -Reflection characteristics of the reflector manufactured by the manufacturing method of the first embodiment 20 ... Reflection characteristics of the reflector manufactured by the manufacturing method of the third embodiment 21, 23 ... Second embodiment Depending on the manufacturing method Reflection characteristics of manufactured reflector 22: Reflection characteristics of reflector manufactured by manufacturing method of fourth embodiment 1001, 1003, 1101, 1103: Glass substrate 1010, 1107, 1110: Transparent Electrodes 1009, 1109 Sealing material 1006, 1106 Protective layer (planarizing film) 1011, 1012, 1111, 1112 Alignment film 1014, 1114, 1116 Phase difference plate 1015, 1115, 1117 ... Polarizing plate 1004, 1104 ... Coloring layer 1005, 1105 ... Adhesion improving layer 1013, 1113 ... Light shielding layer 1118 ... Fluorescent tube 1119 ... Light guide plate 1122 ... On the reflection plate , Transmission openings 121, 124, 126, electronic device display unit 122, portable information device 123, input unit 125 ・ ・ ・ Mobile phone 127 ・ ・ ・ Watch

Continued on the front page F-term (reference) 2H090 HA04 HA05 HB13X HC05 HC08 HC10 HC11 HC12 HC15 HC17 HC18 HC19 HD06 JA03 JA07 JB02 JC03 JC07 JD01 KA05 KA08 KA18 LA04 LA10 LA20 MA04 MB01 5G435 AA00 BB12 BB15 BB27 FF27 FF00 FF08 FF13 GG12 GG24 HH02 KK05 LL07 LL08 LL10

Claims (10)

[Claims] In a liquid crystal device substrate having predetermined irregularities formed on the surface of the substrate, the irregularities have a height of 0.001 μm.
m is randomly provided in the range of not more than the thickness of the liquid crystal layer of the liquid crystal device using the same, and the pitch is randomly provided in the range of 0.001 μm to the length of the short side of the pixel electrode of the liquid crystal device using the same. A substrate for a liquid crystal device, comprising: 2. In a liquid crystal device substrate having predetermined irregularities formed on the substrate surface, the constituent components of the raw material substrate are etched for each minute portion, and the irregularities are formed only by the constituent components of the raw material substrate. Rough irregularities, height 0.001
It is provided randomly in the range of from μm to the thickness of the liquid crystal layer of the liquid crystal device using the same, and is randomly provided in the range of 0.001 μm to the length of the short side of the pixel electrode of the liquid crystal device using the same. A substrate for a liquid crystal device, comprising: 3. The method according to claim 1, wherein the irregularities have a surface layer shape of Ry (J
IS) (maximum height) 0.2-3 μm, Ra (arithmetic average roughness: centerline average) 0.02-0.3 μm, Rz (JI
S) (10-point average roughness) is 0.1 to 2.5 μm, Sm (1%: J
3. The substrate for a liquid crystal device according to claim 1, wherein IS) (average wavelength of unevenness) is quantitatively defined in a range of 4 to 60 μm. 4. The method according to claim 1, wherein the irregularities have a surface shape of Ry (J
IS) (maximum height) is 1.5 to 2.0 μm, Ra (arithmetic mean roughness: centerline average) is 0.15 to 0.3 μm, Rz
(JIS) (ten point average roughness) is 1.3 to 1.8 μm, Sm (1
3. The substrate for a liquid crystal device according to claim 1, wherein (%: JIS) (average wavelength of unevenness) is quantitatively defined in a range of 15 to 25 μm. 5. The method according to claim 1, wherein the irregularities have a surface layer shape of Ry (J
IS) (maximum height) 0.7 to 1.2 μm, Ra (arithmetic mean roughness: centerline average) 0.1 to 0.2 μm, Rz (J
IS) (ten point average roughness) is 0.5 to 1.0 μm, Sm (1%:
3. The liquid crystal device substrate according to claim 1, wherein (JIS) (average wavelength of unevenness) is quantitatively defined in a range of 35 to 50 μm. 6. The method according to claim 1, wherein the unevenness has a surface layer shape of Ry (J
IS) (maximum height) 0.6-1.2 μm, Ra (arithmetic average roughness: centerline average) 0.05-0.15 μm, R
z (JIS) (ten point average roughness) is 0.5 to 1.0 μm, Sm
3. The substrate for a liquid crystal device according to claim 1, wherein (1%: JIS) (average wavelength of unevenness) is quantitatively defined in a range of 15 to 25 [mu] m. 7. The method according to claim 7, wherein the irregularities have a surface layer shape of Ry (J
IS) (maximum height) 0.4-1.0 μm, Ra (arithmetic mean roughness: centerline average) 0.04-0.10 μm, R
z (JIS) (ten point average roughness) is 0.3 to 0.8 μm, Sm
3. The substrate for a liquid crystal device according to claim 1, wherein (1%: JIS) (average wavelength of unevenness) is quantitatively defined in a range of 8 to 15 [mu] m. 8. The method according to claim 8, wherein the irregularities have a surface layer shape of Ry (J
IS) (maximum height) 0.8-1.5 μm, Ra (arithmetic average roughness: centerline average) 0.05-0.15 μm, R
z (JIS) (ten point average roughness) is 0.7 to 1.3 μm, Sm
3. The substrate for a liquid crystal device according to claim 1, wherein (1%: JIS) (average wavelength of unevenness) is quantitatively defined in a range of 8 to 15 [mu] m. 9. A liquid crystal device according to claim 1, wherein a liquid crystal layer is sandwiched between a pair of insulating substrates, and the substrate for a liquid crystal device according to claim 1 is used as one of the insulating substrates. Liquid crystal device. 10. An electronic apparatus equipped with the liquid crystal device according to claim 9.