JP3531569B2 - Manufacturing method of electro-optical device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color reflector, and more particularly to a color reflector and an electrode. Furthermore, the present invention relates to an electro-optical device, and more particularly to an electro-optical device having a color reflector.

[0002]

2. Description of the Related Art Conventionally, a method for forming a transparent electrode on a color filter is disclosed in Japanese Patent Laid-Open No. 233720/1986.
JP-A-61-260224 and JP-A-61-198.
No. 131 or JP-A-62-153826, the shapes and materials of the color filter and the protective layer are proposed. Also, Japanese Patent Laid-Open No. 62-121701
There has been proposed a method of forming a cell by combining an electro-optical device (hereinafter referred to as NTN) capable of supporting a high display capacity proposed in Japanese Patent Publication and the above color filter forming method. In addition, red (hereinafter R
The thickness of the liquid crystal layer is changed according to each color of each color filter of the color liquid crystal display device having a color filter that mainly transmits light of three colors, green (hereinafter referred to as G) and blue (hereinafter referred to as B). A method has been proposed.

[0003]

However, in the above-mentioned prior art, the method of forming the transparent electrode on the color filter has the following problems due to its flatness and heat resistance.
Display unevenness due to cell gap unevenness and display electrodes such as IT
Although the improvement of the characteristics against the deterioration of the electro-optical characteristics due to the large specific resistance of O has been studied, there is no practical type in the reflection type panel which requires black and white and brightness. If a liquid crystal cell is used as the optical compensation layer in the reflective panel, or if an optical compensation film is used, it is possible to provide a color electro-optical device having a large display capacity and capable of displaying in black and white. In the case of NTN, as shown in the spectral reflectance curve of FIG. 7, the spectral reflectance curve is well reflected on the short wavelength side at a low voltage of 10V to 60V, and as the voltage is increased, the wavelength of high reflectance is on the long wavelength side. In order to move to NTN, when combining a color reflector of R, G, B three colors integrated, when the three color filters are driven simultaneously and white display is performed, the light passing through the electro-optical device and reflected is The reflectance of B is high at a low voltage, the reflectances of R and G increase as the voltage increases, and the reflectance of B decreases, moving from a bluish color to a yellowish color as a whole, and the color balance is well There is a problem that had.

Further, the reflectance of the whole light is lowered, and R, G,
B By changing the thickness of each color filter layer and controlling the thickness of the effective liquid crystal layer on each color filter,
Although a method of controlling the shutter property of the liquid crystal layer has been proposed, it is difficult to always control the thickness of the color filter layer with the same film thickness difference. In particular, it is necessary to increase the twist angle of the liquid crystal like NTN and FTN. In addition, there is also a problem that it is difficult to secure the alignment stability of the liquid crystal layer when the liquid crystal layer thickness is different depending on each color filter when the steepness of the optical response is increased.

Therefore, the present invention solves the above problems, and an object of the present invention is to provide a reflective electro-optical device capable of high-quality color display with good reproducibility of bright white and black levels easily and inexpensively. To provide to.

[0006]

According to the method of manufacturing an electro-optical device of the present invention, in the method of manufacturing an electro-optical device having a substrate provided with a reflective layer, the reflective layer is applied with three kinds of electric fields. The method includes the step of providing colored layers of three colors on the layer and the step of providing electrodes on the colored layer.

The method of manufacturing an electro-optical device according to the present invention is the method of manufacturing an electro-optical device having a substrate provided with a reflective layer, wherein an electric field is applied to the reflective layer in three types of electrolytic baths to form a layer on the reflective layer. And a step of providing a colored layer of three colors formed by stacking a metal, an inorganic substance, and an organic substance, and a step of providing an electrode on the colored layer.

The method for manufacturing an electro-optical device according to the present invention further comprises, after the step of providing the colored layer, a step of depositing finely divided metal oxide between the adjacent colored layers to provide a black mask. Characterize.

The method for manufacturing an electro-optical device of the present invention is characterized by further including a step of polishing and planarizing after the step of providing the colored layer.

In the method for manufacturing an electro-optical device of the present invention, after the step of providing the colored layer, a step of forming a low reflection portion by an insulating treatment by anodizing the reflective layer provided with the colored layer is further provided. It is characterized by having. Further, the manufacturing method of the electro-optical device of the present invention is characterized in that, in the step of providing the colored layer, the film thickness of the colored layer is controlled by changing the electrolytic voltage.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described based on Examples.
This will be described in more detail. As the electro-optical device of the present invention, not only those which are twisted and aligned by a well-known conventional alignment treatment but also those which are aligned (not twisted) in parallel with the substrate are applicable. It is not limited to the example. Furthermore, in the case of twist orientation, the twist angle is not limited, but it is 90% from the viewpoint of contrast, display characteristics and manufacturing stability.
Degrees of 360 to 360 are desirable. However, since the twist angle is not limited, it can be applied at less than 90 ° or at 360 ° or more. Further, in FIG. 1, a liquid crystal cell 3 is used as an optically anisotropic body and is arranged above a light control cell (hereinafter referred to as A cell) 4.

The structure of the electro-optical device used in this embodiment will be described with reference to FIG. As shown in FIG. 1, with a color reflector inside, a cell thickness of 7 μm and a left twist of 230 ° were set as A cell 4, and in the present embodiment, the same birefringence as A cell 4 was used as an optically anisotropic body. (Cell gap: product of d and refractive index anisotropy of liquid crystal or optically anisotropic substance: Δn Δn × d =
0.9, Δn = 0.129), and the liquid crystal cell 3 was installed between the polarizers 1 and 2 so that the A cell 4 can be optically compensated. In this embodiment, the liquid crystal cell 3 has Δn × d = 0.9, d = 8 μm, and Δn = 0.113. Here, the angle formed by the orientation directions of the surfaces where the A cell 4 and the liquid crystal cell 3 are in contact with each other is 70
The range is preferably in the range of 90 ° to 110 °, more preferably 90 °. In this embodiment, the angle is 90 °. Further, the angle formed between the polarization axis of each polarizer and the orientation direction on the side where the A cell 4 and the liquid crystal cell 3 are in contact with each other is set to 20 to 50 °, and the birefringence and the refractive index used in this example are adjusted. With respect to the dispersion value, the condition for black when not lit and white when all lit is 45 °. However, whether the polarization axis is right or left when viewed from the top of the electro-optical device with respect to the alignment direction is positive or negative, and in this embodiment, it is made negative. However, as described above, the optically anisotropic body has the same effect as long as it has the same birefringence as that of the A cell. For example, a stretched polymer film such as polyvinyl alcohol or polycarbonate may be used, There are no restrictions.

In the present invention, the optical characteristics of the color reflector are important, and it goes without saying that wide color coordinates of B, G and R are good for color reproducibility. When the metal electrodeposition method is used, the color purity (saturation) and reflectance (brightness) of the color reflector are generally formed by depositing several kinds of metals, so the selection range of the metal compound itself and the electrodeposition conditions is limited. Narrow,
This is due to the particle size distribution of the particle size of the deposited metal. That is, if the particle size distribution is sharp and particles of a certain fixed size are lined up, light of a constant wavelength is absorbed or scattered to give a color close to the primary color. Conversely, if the particle size distribution is broad, a dull color or It tends to be a bronze color. In the case of this method, the relationship between color purity and reflectance is the opposite relationship. Therefore, it is desirable to increase the reflectance within a range that does not significantly deteriorate the color purity. Therefore, from the relationship between color purity and reflectance,
In B, the maximum reflectance is 100 with the color reflector alone.
It is desirable that the reflectance is 80% or more at 0 to 3000 angstroms, and the reflectance is controlled within this range. Further, the ratio of the maximum reflectance of each color reflector is within 1.8, and more preferably within 1.5, the white reproducibility is better. Was set within 1.5 in this example. In the following embodiments, an example according to this relationship will be described. It should be noted that if the ratio of the maximum reflectance values deviates, the color balance is lost, and the entire white color shifts to the color side with the higher reflectance. Next, the relationship of the maximum reflectance wavelength will be described. FIG. 7 shows the spectral characteristics under the above liquid crystal cell conditions when a static voltage is applied and there is no color reflector. However, the numbers in the figure show 100% when the optical response is completely saturated, and show what percentage the response is to 100 below. FIG. 8 shows the spectral characteristics when the wavelengths of the maximum reflectance values of R, G, and B are shifted and formed. When a liquid crystal cell or a stretched polymer film is used as an optically anisotropic body, it can be seen from FIG. 7 that the spectral reflectance curve gradually shifts to the long wavelength side as the applied voltage increases. Therefore, when the maximum reflectance wavelengths of G and B shown in FIG. 8 are closer to the maximum reflectance wavelengths of G and B than the values when the maximum reflectance wavelengths of G and B are 490 nm and 520 nm, respectively, more B is omitted, and It can be easily understood that the spectral reflectance on the short wavelength side overlaps with that on the short wavelength side and the bluish color becomes stronger. Also, the maximum reflectance wavelengths of G and B shown in FIG. 2 are 450 nm and 540, respectively.
The three primary colors R, G, and B are separated by the total spectral characteristics when the optical characteristics of the liquid crystal and the spectral characteristics of the color reflection plate are multiplied as the maximum reflectance wavelengths of G and B become more distant from the value in nm. Therefore, a beautiful additive color mixture relationship is established. In this embodiment, the maximum reflectance wavelength of B is 480 nm or less, more preferably 465 nm or less, and the maximum transmittance wavelength of G is 53.
0 nm or more, more preferably 540 nm to 560 nm
Set between.

Example 1 will be described with reference to FIG. On the glass substrate 5, an electrolytic bath in which a metal compound for electrolytically coloring R, G, and B was dissolved was colored in a stripe shape with a width of 110 μm by the electrolytic coloring method to form the reflective layer 6 and the colored layer 7. (Here, the reflective layer 6 and the colored layer 7 are collectively referred to as a color reflective plate). At this time, the color reflectors are made up of adjacent three-color stripes, and the black mask 8 is formed by depositing finely divided metal oxide so that the black mask 8 has a thickness of 0.1 to 10 μm. In addition, in order to reduce the resistance of the electrode, the metal color reflector and I
To make contact with the TO electrode, use the color reflector 3
A finely divided metal oxide compound was deposited between the color stripes to replace the black mask having an insulating property to prevent color loss in adjacent portions of the color reflector. Next, the structure of the electro-optical device according to the present embodiment will be described with reference to FIG. A transparent insulating film is formed on the color reflector of the glass substrate 3, and an ITO electrode is formed on the transparent insulating film along the three-color stripe. Then, the transparent electrodes 9 are formed of ITO on the glass substrate 5 so as to form a matrix. After that, an alignment film 11 was formed in a thickness of 300 to 400 angstroms using polyimide. At this time, the orientation agent of the glass substrate 5 having the color reflector is 0.8 m below the seal 13.
After being formed to the inner side of m, liquid crystal was sealed via the gap material 12. In this embodiment, the reflectance and maximum reflectance wavelength of each color as the substrate including the transparent electrode described above are as follows: R is 70% reflectance, maximum reflectance wavelength is 620 nm,
G had a reflectance of 60% and a maximum reflectance wavelength of 540 nm, and B had a reflectance of 55% and a maximum reflectance wavelength of 450 nm. The optical characteristic of the electro-optical device formed in this way is 1/40
When a rectangular wave corresponding to 0 duty was applied and the spectral reflectance at that time was examined, it was found that a good 3 value similar to that shown in FIG.
A primary color mixture relationship was obtained. In addition, driving was actually performed by applying a time-division drive waveform and using a three-wavelength cold cathode tube with a luminance of 1600 nit and color coordinates (x, y) = (0.320, 0.336) as a side light source. A white state that can be averaged within the range is obtained. Particularly, the contrast is 8.3 and the surface brightness is 52n on the surface of the electro-optical device when the reflectance ratio (hereinafter referred to as contrast) when the lighting waveform and the non-lighting waveform are applied is maximum.
It, (x, y) = (0.321, 0.325) was obtained, which was a very good result, and a high-quality electro-optical device could be formed.

[Second Embodiment] A second embodiment will be described with reference to FIGS. FIG. 5 shows a sectional view of a substrate with a color reflector according to this embodiment. On the glass substrate 5, the colored layer 7 was electrolytically colored into stripes by the electrolytic coloring method in the same manner as in Example 1 and then polished to form a flat color reflector. At this time, the color stripes had a width of 100 μm, and the distance between the stripes was set to 10 μm after polishing. In the present embodiment, the reflectance and maximum reflectance wavelength of each color as the substrate including the transparent electrode 9 described above are as follows: R is 75% reflectance, maximum reflectance wavelength is 620 nm,
G had a reflectance of 60% and a maximum reflectance wavelength of 540 nm, and B had a reflectance of 60% and a maximum reflectance wavelength of 460 nm. After that, as shown in FIG. 6, when an electro-optical device was formed in the same manner as in Example 1, the same good result could be obtained. In this method, the color stripe portion is covered with a photoresist and subjected to anodizing treatment so that only the low reflection portion is subjected to an insulation treatment, so that it is not necessary to provide an insulating layer made of a resin material, so that the process can be shortened. Greatly improved purity and reflectivity.

Example 3 A method of manufacturing a color reflector will be described with reference to FIGS. FIG. 5 shows a sectional view of a substrate with a color reflector according to this embodiment. At least one layer of aluminum was vacuum-plated on the glass substrate 5 to form a surface having a total reflectance of 90% or more and a reflectance of 85% or more, and then anodized in a solution capable of forming a microporous layer. Next, a solution containing metal ions for example, blue in the bath plus SnS0 ₄ phosphate, red MnSO ₄ and FeSO _4, was subjected to green color by the secondary electrolysis added CuSO ₄ in sulfuric acid bath . Alternatively, in the case of Ni (CH ₃ COO) _{2 in} the phosphoric acid bath and the sulfuric acid bath, three kinds of electric fields were applied to develop three colors. Alternatively, when the secondary electrolysis is performed in three types of baths, not only the state of the metal salt, but also three types of each of the inorganic substance and the organic substance are laminated to develop the color. On this glass substrate 5, a color reflection plate was formed by electrolytically coloring the color reflection plate into stripes and polishing the flatness of the color reflection plate in the same manner as in Example 2. At this time, the color stripe was set to be the same as in Example 2. The feature of this embodiment is that by using aluminum, which has a high reflectance and a low specific resistance, as a color reflector, it is possible to serve as a reflection layer and an electrode. By removing the reflectance to 3% or less, the color loss part was eliminated. Since the overcoat and the ITO film are not required as in Example 2, the structure of the color reflection plate is simplified, and the alkali damage, the poor adhesion of the ITO, etc., which are caused by the presence of the overcoat and the ITO film. There were no defective items, and the yield was greatly improved. Moreover, productivity was improved and cost was reduced by reducing the number of steps.

Example 4 An electro-optical device shown in Example 1 will be described with reference to FIGS. As described in Examples 1, 2, and 3, in the present invention, in the case of an electro-optical device that originally uses a liquid crystal cell or a stretched polymer film as an optically anisotropic body, the voltage is applied as described above. When the voltage has a low spectral reflectance curve, the short wavelength side is well reflected, and as the voltage is increased, the wavelength with high reflectance shifts to the long wavelength side. Therefore, when the electro-optical device is combined with R, G, and B color reflectors, the light reflected by the electro-optical device when the liquid crystal layers on the tri-color reflectors are simultaneously driven to display white. Indicates that the reflectance of B is high at a low voltage, the reflectances of R and G increase and the reflectance of B decreases as the voltage increases, and the overall bluish color changes to a yellowish color. In consideration of the above, the concept is to control the spectral characteristics of the color reflector by correcting the characteristics as a spectral curve in which the color reflector and the side light source are combined. However, in order to further control the optical color arrangement, if the liquid crystal portion between the color reflectors is regarded as an optically non-reflecting portion, if the thickness of the liquid crystal layer is ideally the same, the reflectance of B is different from that of other colors. Since the liquid crystal shutter reflects less, and consequently the liquid crystal shutter of B opens slowly, the same optical behavior is obtained. Therefore, the cell thickness of the liquid crystal portion on B is made thicker than G and R, and the electric field strength applied to the liquid crystal layer is It is effective to intentionally increase the shutter speed of the section B with respect to the voltage by setting the optical threshold value relatively lower than the other colors. Therefore, using the color reflection plate described in Embodiment 1, the thickness of B is 1.5 for other colors.
The spectral reflectance is set to be 0.05 to 0.1 μm thinner than μm, the reflectance of each color as the substrate including the transparent electrode 6 and the maximum reflectance wavelength, and R is 70% reflectance and the maximum reflectance wavelength. Is 620 nm, G is 60% reflectance, the maximum reflectance wavelength is 540 nm, B is 65% reflectance, and the maximum reflectance wavelength is 450 nm. When an electro-optical device was produced in the same manner as in Example 1 using the substrate with a color reflection plate produced in this way, it had characteristics that the optical threshold values of B and other colors were uniform, and that R was missing. On the other hand, it was possible to create an electro-optical device having a good white level in which B was even on the low voltage side.

Although the first and second embodiments and the third embodiment have been described above as examples, the spectral characteristics of the color reflection plate are made uniform, and in addition, the film thickness of the color reflection plate is set to the electrolytic voltage of 5V, 15V, and 6V.
It is possible to obtain an electro-optical device with higher image quality by controlling the voltage by changing it to 5V or the like and matching it with the shutter characteristic of the liquid crystal. At this time, since the film thickness of the color reflection plate has a deep correlation with the metal ion concentration or the metal particle size and the forming conditions, it is important to control the forming process with good reproducibility.

[0019]

As described above, according to the present invention, a flat colored layer can be easily formed on the reflective layer, and high-quality color display with good reproducibility of white and black levels is possible. It is possible to manufacture various reflective electro-optical devices. Further, according to the present invention, it is possible to manufacture an electro-optical device capable of preventing color loss in adjacent portions of the colored layers. Further, according to the present invention, by combining the spectral reflectance control and the film thickness control of the reflector having the colored layer formed,
It is possible to manufacture a high-quality electro-optical device having a color purity with a more uniform optical threshold and a high brightness.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of an electro-optical device shown in an embodiment of the present invention.

FIG. 2 is a diagram showing a spectral characteristic of an electro-optical device having a color reflection plate shown in an embodiment of the present invention.

FIG. 3 is a cross-sectional view of a substrate with a color reflector shown in Examples 1 and 4 of the present invention.

FIG. 4 is a diagram showing the structure of the electro-optical device shown in Examples 1 and 4 of the present invention.

FIG. 5 is a cross-sectional view of a substrate with a color reflector shown in Examples 2 and 3 of the present invention.

FIG. 6 is a diagram showing the structure of the electro-optical device shown in Examples 2 and 3 of the present invention.

FIG. 7 is a diagram showing the relationship of liquid crystal optical characteristics shown in Examples of the present invention.

FIG. 8 is a diagram showing a spectral characteristic of an electro-optical device having a color reflecting plate shown in an example of the present invention.

[Explanation of symbols]

1. Upper polarizer 2. Lower polarizer 3. Liquid crystal cell 4.A cell 5. Glass substrate 6. Reflective layer 7. Colored layer 8. Black mask (anodized layer) 9. Transparent electrode 10. Transparent insulating film 11. Alignment film 12. Gap material 13. Seal

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Claims (5)

(57) [Claims] 1. A method comprising: applying three types of electric fields to a reflective layer provided on a substrate to form colored layers of three colors on the reflective layer; and providing electrodes on the colored layer. In the method for manufacturing a characteristic electro-optical device, the colored layer is provided after the step of providing the colored layer.
In addition, the reflection resistance of the reflective layer is reduced by the anodizing treatment.
A method of manufacturing an electro-optical device, comprising the step of forming a projected portion . 2. In the step of providing the colored layer, an electric field is applied to the reflective layer in three types of electrolytic baths to provide a colored layer of three colors composed of a stack of a metal, an inorganic substance and an organic substance on the reflective layer. The method of manufacturing an electro-optical device according to claim 1, further comprising a step. 3. The method according to claim 1, further comprising, after the step of providing the colored layer, a step of depositing finely divided metal oxide between adjacent colored layers to provide a black mask. A method for manufacturing the electro-optical device described. 4. The method of manufacturing an electro-optical device according to claim 1, further comprising a step of polishing and planarizing after the step of providing the colored layer. 5. The method for manufacturing an electro-optical device according to claim 1, wherein in the step of providing the colored layer, the film thickness of the colored layer is controlled by changing an electrolytic voltage.