JP3311894B2 - Color filter and color display method - 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 filter used for a liquid crystal color television receiver, a CCD and the like, and a color display method used for a liquid crystal color television receiver and the like.

[0002]

2. Description of the Related Art At present, a CRT is widely demanded as a display element. In order to display all pixels with one electron gun, the CRT has to increase the depth dimension of the display, and is not suitable for a portable panel in terms of power consumption and weight. Other displays include plasma, EL, etc.
All of them have problems in practical use as portable panels because of their large power consumption.

[0003] Liquid crystal elements are the only portable display elements that are currently in practical use, and are widely used as display elements for watches, calculators and the like because they can be thinned and driven at low voltage. In particular, by incorporating an active switch element such as a TFT, a TN-type liquid crystal display system can be provided with display characteristics comparable to a CRT, and is being used in televisions and the like. However, the TN-type liquid crystal display element uses a polarizing plate and thus has a low light use efficiency and uses a backlight to increase the amount of light. However, this causes a problem of an increase in power consumption. In particular,
In the case of performing TFT color display, only a few percent of light use efficiency with respect to the total light amount can be obtained due to the low aperture ratio of pixels and the use of RGB color filters. In order to obtain a bright display, the luminance of the backlight must be increased, which leads to an increase in power consumption.

On the other hand, a color reflection type liquid crystal display device has been studied for the purpose of reducing power consumption. However, since a backlight is not used, in a display using a color filter, colors are hardly visually recognized. You can only get a dark display of.

[0005]

As described above, the light use efficiency can be improved by increasing the transmittance of the entire wavelength of transmitted light, but the saturation of the target color is increased to achieve a clear color. In order to obtain, it is desirable to transmit only a specific wavelength. As described above, the light use efficiency and the color saturation are in a contradictory relationship, and it has been difficult to achieve both. Accordingly, it is an object of the present invention to provide a color filter which achieves low power consumption of a color liquid crystal display element and can perform bright and clear display.

[0006]

In order to solve the above-mentioned problems, the present invention (claim 1) uses a wavelength range of transmitted light when displaying a target color for displaying a target color. A first wavelength region, a second wavelength region used for displaying other colors and not affecting the sharpness of a target color, and a target color used for displaying other colors and Is divided into three types of wavelength regions of a third wavelength region that affects the sharpness of the light, and the average value of the spectral transmittance in each wavelength region is T ₁ > T ₂ > T ₃ (where T ₁ , T _{1 2} and T ₃ are the average values of the spectral transmittances of the first wavelength region, the second wavelength region, and the third wavelength region, respectively.) I do.

In the present invention, the target color indicates any one of blue, green, and red, and the other colors indicate the other two colors. Therefore, when one of the x value and the y value of the chromaticity coordinates of the transmitted light is out of the range shown below, it means that the saturation of the target color has been reduced.

The range of the chromaticity coordinates of each color is as follows. Blue x ≦ 0.182, y ≦ 0.170 Green x ≦ 0.337, y ≧ 0.511 Red x ≧ 0.55, y ≦ 0.35 That is, the x and y values of the chromaticity coordinates of the transmitted light Is within these ranges, the saturation of the target color does not decrease.

The average value of the spectral transmittance in each wavelength region refers to the average value of the transmittance at every 1 nm in a limited wavelength region. When displaying blue, the first wavelength region is 380 nm to 490 nm, the second wavelength region is 490 nm to 530 nm, and the third wavelength region is 530 nm to 650 nm. The average value of the transmittance is 60% or more, the average value of the spectral transmittance in the second wavelength region is 50% or more and 90% or less, the average value of the spectral transmittance in the third wavelength region is 30% or less, and , 650 nm to 780 nm in the range of 10% or more, and 590 to 650 nm in the range of 15% or less.

Preferably, the average value of the spectral transmittance in the range from 380 nm to 440 nm is 60% or more, and
The average value of the spectral transmittance from 0 nm to 490 nm is 70
% Or more.

The average value of the spectral transmittance in the range from 530 nm to 590 nm is 590 nm to 780 nm.
It is preferable to change according to the average value of the spectral transmittance in the range of from 590 nm to 780 nm.
In the case of 0% or less and 30% or more, it is preferable to set it to 20% or less.

When displaying green, the first wavelength range is 480 nm to 600 nm, and the second wavelength range is 380 nm.
a second wavelength range of 430 nm to 780 nm, a third wavelength range of 430 nm to 460 nm, an average value of the spectral transmittance of the first wavelength range of 65% or more, and a third wavelength range of Has an average value of less than 10%, and in the second wavelength region,
The relationship between the following expressions (1) and (2) is satisfied, and 51
The average value of the spectral transmittance in the range of 0 to 560 nm is 80.
% Or more.

0.1 T _{480 500} ≦ T ₄₀₀ ≦ 1.6 T _{480 500} (1) 0.05 T _{580 600} ≦ T ₆₃₀ ≦ 0.7 T _{580 600} (2) Here, T ₄₀₀ and T ₆₃₀ are each 400 nm.
And the average value of the spectral transmittance at 630 nm.
T _{480 500} and T _{580 600} are each 480 nm
Mean spectral transmittance from 500 to 500 nm, and 580
The average value of the spectral transmittance in the range of nm to 600 nm.

When displaying red, the first wavelength range is 600 to 780 nm and the second wavelength range is 38 to 780 nm.
0 to 510 nm, and the third wavelength region is
10 to 560 nm, the average value of the spectral transmittance in the first wavelength region is 85% or more, the average value of the spectral transmittance in the second wavelength region is 10% or more, and the spectral transmittance in the third wavelength region Is less than 5% and 580 to 60
0 nm is 60% or more.

The color filter of the present invention can be produced by mixing a binder resin, an ethylenically unsaturated compound, a photopolymerization initiator, and a colorant.
Examples of the production method include, but are not limited to, a pigment dispersion method, a dye dispersion method, an electrodeposition method, and a dyeing method.

For example, in the case of manufacturing by a pigment dispersion method, a colored photopolymerizable resin composed of a binder resin, an ethylenically unsaturated compound, a photopolymerization initiator, and a colorant can be used.

As the binder resin, a polymer which is colorless and transparent, and is excellent in heat resistance and light resistance is preferable. Specifically, for example, epoxy resin, melamine resin, acrylic resin, polyimide resin, polyamic acid resin, polyester resin, Unsaturated polyester resin, polycarbonate resin,
Examples thereof include photosensitive monomers and oligomers having a (meth) acryloyl group.

Examples of the ethylenically unsaturated compound include styrene, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate,
Isopropyl (meth) acrylate, n-butyl (meth) acrylate, SEC-butyl (meth) acrylate, tert-butyl (meth) acrylate, iso-butyl (meth) acrylate, n- (meth) acrylate Pentyl, methylstyrene, hydroxyethyl (meth) acrylate,
Examples include mono- or polyvalent monomers such as ethylene glycol dimethacrylate and pentaerythritol tri (meth) acrylate, and ordinary photopolymerizable resins such as polyester (meth) acrylate, polyurethane (meth) acrylate, and epoxy (meth) acrylate.

Examples of the photopolymerization initiator include α-aminoacetophenone, anthraquinone, benzoylethyl ether, benzyl, benzophenone, 4,4′-bisdimethylaminobenzophenone, 4,4′-bistrichloromethylbenzophenone, dibutylphenyl Phosphine, α, α′-diethoxyacetophenone, 2-ethylanthraquinone, benzoylbisphenyl, chlorobenzophenone, benzoin, benzoin methyl ether,
Benzoin isobutyl ether, anthraquinone thioxanthone, methylorthobenzoylbenzoic acid, para-dimethylaminoacetophenone and the like.

These photopolymerization initiators are usually added at a ratio of about 0.1 to 20% by weight based on the total solid content.
As the colorant, those excellent in heat resistance and light resistance are desirable. For example, azo chelate type, condensed azo type, phthalocyanine type, benzimidazolone type, quinacridone type,
Isoindolinine, pyranthrone, anthrapyrimidine, dibromoanzanthrone, indanthrone, freurone, perylene, perinone, quinophthalone, thioindigo, dioxazine, anthraquinone, and pyrrolopyrrole pigments Etc. can be used.

More specifically, pigments represented by the following color index (CI) numbers can be mentioned. C. I. Yellow pigment 20, 24, 83, 86, 93, 1
09, 110, 117, 125, 137, 138, 14
7, 148, 153, 154, 166, 168 C.I. I. Red pigment 9, 97, 122, 123, 14
9, 168, 177, 180, 192, 208, 21
5, 216, 217, 220, 223, 224, 22
6, 227, 228, 240 C.I. I. Purple pigment 19, 23, 29, 30, 37, 4
0, 50 C.I. I. Blue pigment 15, 15: 1 to 6, 22, 60,
64 C.I. I. Green pigment 7, 36 By adjusting the kind, amount and mixing ratio of these colorants, the transmittance can be adjusted according to the target color.

In producing the color filter of the present invention, first, a predetermined pigment is dissolved in concentrated sulfuric acid and stirred at room temperature for 2 hours. This sulfuric acid solution is poured into an excessive amount of ice water over 1 hour while stirring to form a slurry. Next, the mixture was stirred at room temperature for 1 hour, the pigment slurry was filtered with a filter, washed with water until neutral, and then dried at 80 ° C.
To this, a sorbitan fatty acid ester-based compound and ethylcellosolve acetate were added as a dispersant, and the mixture was dispersed with a sand mill. The average particle size of the pigment solid solution dispersion paste thus obtained was 200 nm or less.

This paste is added to a photopolymerizable resin to which a photopolymerization initiator has been added in advance, mixed with stirring, and then filtered to obtain a uniform mixture. The obtained mixture is applied on a transparent substrate to a thickness of about 1.5 to 2 μm by using a spin coating method or the like, and dried at 70 to 90 ° C. for about 3 minutes. Further, the color filter of the present invention can be obtained by irradiating light with an ultrahigh pressure mercury lamp and developing with an alkali developing solution.

The spectral spectrum of the color filter of the present invention can be realized not only by using a coloring agent such as a dye or a pigment but also by a multilayer film. Further, according to the present invention (claim 5), a wavelength region of a spectrum when a target color is displayed is used as a first wavelength region used for displaying a target color, and a first wavelength region used for displaying another color. Is divided into three wavelength regions, a second wavelength region that does not reduce the saturation of the color to be used, and a third wavelength region that is used for displaying other colors and reduces the saturation of the target color. And the spectral intensity of each wavelength region is I ₁ > I ₂ > I ₃ (where I ₁ , I ₂ and I ₃ are the first wavelength region, the second wavelength region, and the third wavelength region, respectively) The present invention provides a color display method characterized in that a color display is performed using a spectral transmission spectrum that gives a spectral intensity.

The color display method of the present invention can be implemented by using the color filter of the present invention in which the transmittance of each wavelength is adjusted to adjust the spectral spectrum to a predetermined shape. Further, in addition to this, the adjustment can be performed by spatially or temporally superimposing while adjusting the luminance of a plurality of spectral spectra.

In the case of spatially overlapping, the mixing ratio can be determined by adjusting the voltage applied to a predetermined pixel of the liquid crystal display element. In the case of temporal overlapping, for example, in the case of blue display, for example, red is transmitted immediately after blue and mixed, or the spectral spectrum is adjusted by temporally changing the amount of red light. be able to. In the case of green display, the spectrum can be adjusted by mixing blue light, and in the case of red display, the spectrum can be adjusted by mixing blue light, for example.

Further, by partially illuminating pixels other than the color filter used for displaying a target color, it is possible to temporally overlap the pixels. further,
A specific auxiliary filter may be provided in addition to the color filter. The auxiliary filter can be appropriately selected according to the desired color to be displayed.For example, a blue auxiliary filter is provided in the same pixel to obtain a red filter, and a blue auxiliary filter is provided to realize green. Alternatively, a red filter can be provided, and a red filter can be provided to realize blue.

[0028]

The present inventors have examined light in a wavelength region that is not used for displaying a target color and found that the light can be divided into two regions. That is, without reducing the saturation of the intended original color,
There are two wavelength regions, a preferable region in which the brightness of the color can be increased, and a region in which the saturation of the target color is remarkably degraded. Therefore, a wavelength region used for displaying a target color is referred to as a first wavelength region, and a wavelength region for increasing the brightness of the target color and a wavelength region for decreasing the saturation among the other regions. Were defined as second and third wavelength regions, respectively, and the average value of the spectral transmittance in each region was determined.

Since the spectral transmittance of the color filter of the present invention is set in this manner, the light use efficiency (luminous transmittance) used for color display can be increased while maintaining the original color saturation. Can be.

The present invention has been made based on the following findings. We randomly selected 100
A test is performed on a person under an environment where the illuminance is 50 lux to 500 lux to indicate a color plate having a luminous reflectance of 5% or more and a different color tone and determine the color. For each of the red, green, and blue colors, The minimum required area for display was examined. As a result, the chromaticity coordinates of each color were determined, and the spectral spectrum was adjusted to satisfy each condition, thereby achieving both light use efficiency and chroma.

Hereinafter, the results of the examination for each color will be described in detail. In the description, the average value of the spectral transmittance refers to the average value of the transmittance every 1 nm in a limited wavelength region.
First, a region where all the subjects can feel blue is indicated by hatching in the chromaticity coordinates of FIG. From this result, the minimum area required for blue display is the chromaticity coordinate (x ≦
0.182. It can be seen that y ≦ 0.170).

Next, the wavelength region from 380 nm to 780 nm was divided into a plurality of regions, and the influence of each region on blue, its spectral transmittance, and the like were considered. In FIG.
Average value T of spectral transmittance from 80 nm to 440 nm
_{380 440} shows the relationship between the chromaticity change (y value). The light in this range is a region where the y value is reduced in the chromaticity coordinates to obtain a clear blue color and the brightness can be increased. Therefore,
From FIG. 2, the average value T _{380 440} of the spectral transmittance in the range from 380 nm to 440 nm is 60% or more, and 70%
It turns out that the above is preferable. If it is less than 60%, the luminance may be low, and the influence of light in other wavelength regions may be large, so that the saturation may be easily lowered.

FIG. 3 shows the average value T _{440 490} of the spectral transmittance from 440 nm to 490 nm and the chromaticity change (x value).
And changes in luminous reflectance (Y value). Light in this range is the most important area to get a clear blue,
It is an area where brightness can be obtained. FIG. 3 shows that the average value T _{440 490} of the spectral transmittance is 60% or more, preferably 70% or more, and more preferably 80% or more.
If it is less than 60%, the luminance may be low, and the influence of light in other wavelength regions may be large, so that the saturation may be easily lowered.

FIG. 4 shows the average value T _{490 530} of the spectral transmittance from 490 nm to 530 nm and the chromaticity change (x value,
(y value) and a change in luminous reflectance (Y value).
The light in this range is an area where the brightness is greatly increased and the x value of the chromaticity coordinates is significantly reduced to maintain the clearness of blue. Therefore, according to FIG. 4, the average value T _{490 of the} spectral transmittance is obtained.
₅₃₀ is 50% or more and 90% or less. If it is less than 50%, the x value increases in the chromaticity coordinates and the color becomes purplish blue, while if it exceeds 90%, the y value increases in the chromaticity coordinates and the saturation as blue is impaired and the color becomes greenish. It turns blue. The average value of the spectral transmittance in this range is preferably 60% or more and 90% or less.

FIG. 5 shows the relationship between the average value T _{530 590} of the spectral transmittance in the range of 530 nm to 590 nm, the chromaticity coordinates (y value) and the luminous reflectance (Y value). Light in this range is a region where brightness can be greatly increased, but light in this region greatly increases the y value in chromaticity coordinates,
Significant loss of blue saturation. Note that FIG.
Average value T of spectral transmittance in the range of 90 nm to 780 nm
_{590 780} shows the case of less than 30%, in FIG. 5 (b), T _{590 780} shows a T _{530 590} in the case of 30% or more. From FIGS. 5 (a) and (b), T _{590 780}
It can be seen that, below 30%, 30% or more is preferable below this, and 20% or less is preferable above this.

FIG. 6 shows the spectral transmittance T _{590 650 in} the range from 590 nm to 650 nm and the change in chromaticity (x value, y
Value). Increasing the light in this range can increase brightness, but also increases the x and y values, significantly reducing the blue saturation. In particular, since the width of increase of the x value becomes remarkable, the average value T _{590 650} of the transmittance in this region needs to be suppressed to 15% or less from FIG. If it is 15% or more, a clear blue color cannot be obtained.

FIG. 7 shows the spectral transmittance T _{650 780} of light in the range of 650 nm to 780 nm and the chromaticity change (x value,
(y value) and a change in luminous reflectance (Y value).
Light in this range has little effect on blue saturation and can increase brightness. From FIG. 7, the average value T _{650 780} of the spectral transmittance is set to 10% or more.

Next, the green display will be described. The minimum area required to display this color is the chromaticity coordinates (x,
y) = (x ≦ 0.337, y ≧ 0.511). As shown in FIG. 8, the color function y coincides with the relative luminous efficiency curve, for example, to enhance the sharpness of green. Therefore, in order to obtain a bright and clear display in green, 480 nm
From 600 to 600 nm as much as possible,
First of all it is necessary. Average value of spectral transmittance T _{480 600}
Is at least 60%, more preferably at least 80%. If it is less than 60%, the luminance is low and the influence of light in other wavelength regions is large, so that the saturation is also low.

In particular, the range from 510 nm to 560 nm is an important area for securing the brightness.
The average value T _{510 560} of the spectral transmittance of only this region is 80
% Or more, preferably 90% or more. If it is less than 80%, sufficient brightness cannot be obtained.

When T _{480 600} = 80%,
As shown in FIG. 9, the Y value can be further increased by setting the spectral transmittance in the range from 510 nm to 560 nm to 85% or more.

Light having a wavelength in the range of 430 nm to 460 nm is a region that provides brightness. However, when the spectral transmittance in this region is increased, the y value of the chromaticity coordinates is greatly increased as shown in FIG. And the sharpness of green is greatly impaired. Therefore, the average value of the spectral transmittance T _{430 460} in this region is less than 10%, and more preferably less than 5%.

The wavelength range from 380 nm to 425 nm is a region where the brightness is increased and the x value is further reduced to prevent the color from approaching the yellow region. For this reason, an appropriate transmittance is required. Specifically, 400 nm
It is necessary to make the transmittance T ₄₀₀ or less 1.6 times 0.1 times the average value T _{480 500} transmittance from 480nm to 500 nm.

Since the wavelength range from 605 nm to 780 nm is also an important area for gaining brightness as described above, an appropriate transmittance is required. However, if too large x value is increased, since the green saturation decreases, 6
The transmittance T ₆₃₀ of 30 nm, 600 nm from 580nm
0.05 times or more of the average value T _{580 to 600} of the transmittance up to 0.
It is necessary to make it 70 times or less.

The average value of the transmittance in the range from 380 nm to 425 nm and the average value of the transmittance in the range from 605 nm to 780 nm are closely related, and it is important to maintain a balance between the two. Since the Y value representing the brightness is increased particularly in the range of 605 nm to 700 nm, it is preferable to increase the transmittance in this region. However, in this case, since the x value increases with the Y value, the saturation of green is reduced. Therefore, by increasing the transmittance in the range from 380 nm to 425 nm, it is possible to increase the brightness while maintaining the green saturation by reducing the x value.

Next, the display of red color will be described. The minimum area required for displaying this color was obtained as chromaticity coordinates (x, y) = (x ≧ 0.55, y ≦ 0.35). Since the wavelength range from 580 nm to 780 nm is a region where a clear red is obtained, the average value T _{580 780} of the spectral transmittance is 85% or more as shown in FIG.
0% or more is preferable. If it is less than 85%, the luminance is low, and the influence of light in other wavelength regions increases,
The saturation also decreases.

In particular, the range from 580 nm to 600 nm is an important area for securing the brightness.
The average value T _{580 600} of the transmittance only in this region is 60% or more, preferably 70% or more. If it is less than 60%, sufficient brightness cannot be obtained.

When the transmittance in the region from 580 to 600 nm is increased, the Y value increases as shown in FIG. 12, but the y value of the chromaticity coordinates also increases. Wavelength from 510 nm to 5
Average value of spectral transmittance T _{510 in} the range up to 60 nm
FIG. 13 shows the relationship between ₅₆₀ and chromaticity coordinates (y value) and luminous reflectance (Y value). FIG. 13 shows that when the transmittance in this range is increased, the Y value increases rapidly, but the y value also increases rapidly. That is, although the light in this range is a region that provides brightness, if the transmittance in this region is increased, the sharpness of red is greatly impaired. Therefore, the average value T _{510 560} of the spectral transmittance in this region is 5
%, Preferably less than 1%.

When the wavelength is in the range of 380 nm to 510 nm, the brightness is increased, and in the range of 580 nm to 780 nm.
Since the color tone is adjusted in balance with the area of m, the average value of the spectral transmittance is 10% or more, preferably 12% or more.

The spectral transmittance in the range from 380 nm to 510 nm, the chromaticity change (y value) and the luminous reflectance (Y
14) are shown in FIG. In FIG. 14, T _{580 600} = 95%. As shown in FIG. 14, when T _{380 510} is increased, the y value is reduced to become clear red, and the Y value is also increased.

In particular, it is more preferable that the average value of the transmittance in the range of 490 nm to 505 nm is 15% or more. By ensuring sufficient transmittance in this area,
A bright display can be obtained while maintaining the sharpness of red.

Based on the above considerations, the present inventors have determined a spectral spectrum that can display blue, green, and red clearly and brightly. That is, in the color filter of the present invention, in addition to increasing the transmittance in the wavelength region used to display the original color, the color filter is also specified in the wavelength region used to display other colors. Since the transmittance of the region is increased, the saturation of the target color and the light use efficiency can be simultaneously improved.

According to the color display method of the present invention, in addition to increasing the spectral intensity of the wavelength region used for displaying the original color, the wavelength region used for displaying other colors is further improved. In this case, since a spectral transmission spectrum in which the spectral intensity of a specific region is enhanced is formed, it is possible to achieve both the desired color saturation and light use efficiency.

[0053]

Hereinafter, the present invention will be described with reference to specific examples.
The present invention is not limited to this. (Example I) In this example, a pigment was dispersed in a resist and a solvent, a color filter for blue display was produced by a pigment dispersion method of patterning, and the chromaticity and chroma of the obtained spectral spectrum were compared. did.

As the resist, an epoxy acrylate photopolymerizable resin mixed with 1.0% of lucirin TPO as a photopolymerization initiator was used. Examples of the pigment include C.I.
I. Pigment Red 97, C.I. I. Pigment Red 122, C.I. I. Pigment Red 149, C.I.
I. Pigment Red 168, C.I. I. Pigment
Red 177, C.I. I. Pigment Red 180,
C. I. Pigment Red 192, C.I. I. Pigment Red 215, C.I. I. Pigment Green 7,
C. I. Pigment Green 36, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 1
5: 4, C.I. I. Pigment Blue 15: 6, C.I.
I. Pigment Blue 22, C.I. I. Pigment Blue 60, C.I. I. Pigment Blue 64 was used.

After the pigment was made into a solid solution dispersion paste, it was added to the photopolymerizable resin and mixed with stirring. After filtering the obtained mixture, it was spin-coated on a transparent substrate to a thickness of 2 μm. Further, after drying at 85 ° C. for 3 minutes, ultraviolet rays were irradiated at 100 mJ / cm ² , and development was performed with an alkali developing solution to produce a color filter of Example (I-1).

Further, color filters of Example (I-2) and Example (I-3) were produced in the same manner except that the combination, amount and ratio of the pigment were changed. In addition, a color filter having an increased transmittance over the entire region including the original blue wavelength region was manufactured as Comparative Example I, and a filter that transmits only light in the original blue wavelength region was manufactured. I.

FIGS. 15 to 17 show Examples (I-1) to (I).
3 shows the shape of each spectral spectrum of light transmitted through the color filter. Similarly, the shapes of the spectral spectra of Comparative Example I and Conventional Example I are shown in FIGS.
It is shown in FIG. Further, Table 1 shows the chromaticity and luminance of light that has passed through the color filters of these Examples and Comparative Examples.

[0058]

[Table 1]

From the spectral transmission spectrum of the color filter of the embodiment (I-1) shown in FIG. 15, the average value of the spectral transmittance in each wavelength region was obtained as follows. 90% or more from 380 nm to 440 nm 90% or more from 440 nm to 490 nm 95% or more from 490 nm to 530 nm 70% or more from 590 nm to 650 nm Less than 1% From 650 nm to 780 nm 90% or more This is the shape of the spectrum.

Further, as shown in Table 1, the embodiment (I-
The light transmitted through the color filter of 1) has excellent chromaticity in both the x value and the y value, and the Y value is extremely high at 24.96%, indicating that bright and clear blue was obtained.

The embodiment shown in FIGS. 16 and 17 (I-
From the spectral transmission spectra of the color filters of 2) and Example (I-3), the average value of the spectral transmittance in each wavelength region was obtained as follows.

Example (I-2) Example (I-3) From 380 nm to 440 nm 90% or more 70% or more From 440 nm to 490 nm 90% or more 90% or more From 490 nm to 530 nm 60% or more 50% or more 590 nm to 650 nm Up to less than 10% Less than 5% From 650 nm to 780 nm 10% or more 70% or more As described above, Example (I-2) and Example (I-3)
The transmittance of the color filter is from 380 nm to 530.
In the range up to nm. Further, as shown in Table 1, the x value and the y value of the chromaticity coordinates are good, and the Y value as much as 20% or more, which is much higher than that of the conventional example, is obtained, and a bright and clear blue color is obtained. You can see that

In the embodiment (I-3) shown in FIG. 17, the average value of the transmittance in the range from 380 nm to 530 nm is lower than that of the embodiment (I-1) and the embodiment (I-2). It can be seen that the Y value is lower than in these examples. From this result, it is understood that it is important to increase the transmittance from 380 nm to 440 nm as much as possible in order to secure sufficient brightness.

FIG. 18 shows the spectral transmission spectrum of the color filter of Comparative Example I. Specifically, the average value of the spectral transmittance in each wavelength region is as follows. From 380 nm to 440 nm, less than 60% From 440 nm to 490 nm 90% or more From 490 nm to 530 nm 60% or more, from 590 nm to 650 nm, less than 10% From 650 nm to 780 nm, less than 1% Since the transmittance was increased as a whole over the entire visible light region, as shown in Table 1, the Y value was greatly increased and the brightness could be increased. However, 650n
The average value of the spectral transmittance in the range of m to 780 nm is 10%
As shown in Table 1, the y value of the chromaticity coordinates increased remarkably, and the saturation of blue was so low that it could not be used for a color filter. When the y-value of the chromaticity coordinates increases as described above, the transmitted light becomes greenish.

FIG. 19 shows the spectral transmission spectrum of the color filter of Conventional Example I. Specifically, the average value of the spectral transmittance in each wavelength region is as follows. From 380 nm to 440 nm, less than 60% From 440 nm to 490 nm, less than 70% From 490 nm to 530 nm, less than 50% From 590 nm to 650 nm, less than 1% From 650 nm to 780 nm, less than 1%
Only has a transmittance of about 65% in the wavelength region of
The transmittance in the wavelength range of 650 to 780 nm is less than 1%. Therefore, as shown in Table 1, although the saturation is high, the Y value is extremely small and the brightness is insufficient. That is, since the color filter of the conventional example I has low light use efficiency, there is a problem that power consumption increases when used in a color liquid crystal display device. Further, such a filter having a low light use efficiency cannot be used for a liquid crystal display element that does not use a backlight, such as a color reflection type liquid crystal display element.

According to the present embodiment, a color filter having a clear color and transmitting blue light having a Y value indicating the brightness, which is much larger than the conventional one, was obtained. Subsequently, an example of implementing the color display method of the present invention by adjusting the drive waveform is shown as Example (I-4).

FIGS. 20 and 21 show the RGB values respectively.
Spectra of three color filters and TN
FIG. 3 shows a voltage-transmittance curve of a liquid crystal display device. First, a TN-type liquid crystal display device was prepared in the following procedure. TF
After T was formed on the substrate, the solvent-soluble polyimide was
It was applied to a thickness of 0 Å, baked at 180 ° C., and rubbed. The same processing was performed on the color filter whose spectral spectrum was adjusted. After sandwiching a 6 μm spacer and overlapping the substrates, P-type liquid crystal was injected and the injection port was sealed to obtain a liquid crystal display device.

The blue pixel of this liquid crystal display element has 0 V,
A display spectrum obtained by applying a voltage of 5 V to the green pixels and a voltage of 2.5 V to the red pixels is shown in FIG. Specifically, the average value of the spectral transmittance in each wavelength region is
It is as follows.

From 380 nm to 440 nm 90% or more From 440 nm to 490 nm 90% or more From 490 nm to 530 nm 50% or more From 590 nm to 650 nm Less than 15% From 650 nm to 780 nm 30% or more That is, by adjusting the applied voltage, It is possible to increase the spectral intensity in a wavelength region where the brightness is increased without decreasing the saturation to a desired magnitude.

It has been found that such a color display method provides good display as shown in Table 1. (Example II) In this example, a pigment was dispersed in a resist and a solvent to produce a color filter for green display by a pigment dispersion method of patterning, and the chromaticity and chroma of the obtained spectral spectrum were compared. did.

Lucilin T as a resist photopolymerization initiator
An epoxy acrylate photopolymerizable resin containing 1.0% of PO was used. After the pigment was made into a solid solution dispersion paste, it was added to the photopolymerizable resin and mixed with stirring. After filtering the obtained mixture, it was spin-coated on a transparent substrate to a thickness of 2 μm. Further, after drying at 85 ° C. for 3 minutes, ultraviolet rays were irradiated at 80 mJ / cm ² , and development was performed with an alkali developing solution to prepare a color filter of Example (II-1).

Further, color filters of Example (II-2) and Example (II-3) were prepared in the same manner except that the combination, amount and ratio of the pigment were changed. In addition, a color filter with increased transmittance over the entire region including the original green wavelength region was manufactured as Comparative Example II, and a filter that transmits only light in the original green wavelength region was manufactured. II.

FIGS. 23 to 25 show Examples (II-1) to (II).
3 shows the shape of each spectral spectrum of light transmitted through the color filter. Similarly, Comparative Example II and Conventional Example
The shape of the spectral spectrum of II is shown in FIGS. 26 and 2, respectively.
FIG. Further, Table 2 shows the chromaticity and luminance of the light passing through the color filters of these Examples and Comparative Examples.

[0074]

[Table 2]

From the spectrum of light transmitted through the color filter of Example (II-1) shown in FIG. 23, the average value of the spectral transmittance in each wavelength region was obtained as follows. 90% or more from 480 nm to 600 nm 90% or more from 510 nm to 560 nm 90% or more from 430 nm to 460 nm Less than 1% Further, the spectral transmittance at 400 nm and 630 nm is
They were 50% and 13%, respectively. Note that this 40
The transmittance at 0 nm corresponds to about 0.56 times the average value of the spectral transmittance from 480 nm to 500 nm, and is 630 nm.
Corresponds to about 0.14 times the average value of the spectral transmittance from 650 nm to 780 nm. Such a spectral spectrum is a spectrum shape that makes the best use of the present invention.

Further, as shown in Table 2, the example (II-
The light transmitted through the color filter of 1) has a Y value of 85%.
As described above, the brightness is twice that of the related art, and the color is clear. From the spectral spectra of the light transmitted through the color filters of Examples (II-2) and (II-3) shown in FIGS. 24 and 25, the average value of the spectral transmittance in each wavelength region and the like are as follows. Was obtained.

Example (II-2) Example (II-3) From 480 nm to 600 nm 90% or more 70% or more 510 nm to 560 nm 90% or more 90% or more From 430 nm to 460 nm Less than 1% Less than 5% 400 nm 50% 65% 630 nm 10% 20% Thus, Example (II-2) and Example (II-3)
Change the spectral spectrum from 605 nm to 780 nm,
The spectral transmittance at m is limited within the scope of the present invention. Further, as shown in Table 2, both the x and y values of the chromaticity coordinates were good, and a high Y value of 83% or more was obtained, indicating that a bright and clear green color was obtained.

In the embodiment (II-3) shown in FIG. 25, the average value of the transmittance in the range from 480 nm to 600 nm is lower than that of the embodiment (II-1) and the embodiment (II-2). It can be seen that the Y value is lower than in these examples. From these results, it is understood that it is important to increase the transmittance from 480 nm to 600 nm as much as possible in order to secure sufficient brightness.

FIG. 26 shows a green spectral spectrum of the color filter of Comparative Example II. In particular,
The average value of the spectral transmittance in each wavelength region is as follows.

From 480 nm to 600 nm 80% or more From 510 nm to 560 nm 95% or more From 430 nm to 460 nm 17% or more As described above, in Comparative Example II, the transmittance from 430 nm to 460 nm, which is a region that impairs green sharpness, As shown in Table 2, the saturation of green is so low that it cannot be used as a color filter. Moreover, no remarkable increase in brightness has been obtained.

FIG. 27 shows a green spectral spectrum of the color filter of Conventional Example II. Specifically, the average value of the spectral transmittance in each wavelength region is as follows.

80% or more from 480 nm to 600 nm 95% or more from 510 nm to 560 nm 17% or more from 430 nm to 460 nm Note that the spectral transmittances of 400 nm and 630 nm, which are wavelength regions that require brightness, are both less than 1.0%. Met. Therefore, as shown in Table 2, the light transmitted through the filter of Conventional Example II has an extremely small Y value of 43.25% and is insufficient in brightness. That is, the color filter of Conventional Example II has low light use efficiency,
When used for a color liquid crystal display device, there is a problem that power consumption is increased. Further, such a filter having a low light use efficiency cannot be used for a liquid crystal display element that does not use a backlight, such as a color reflection type liquid crystal display element.

According to the present embodiment, a color filter having a clear color and transmitting green light having a much larger Y value indicating the brightness than the conventional one was obtained. (Example III) In this example, a pigment was dispersed in a resist and a solvent, and a color filter for red display was produced by a pigment dispersion method of patterning, and the chromaticity and chroma of the obtained spectral spectrum were compared. did.

Luciline T as a resist photopolymerization initiator
An epoxy acrylate photopolymerizable resin containing 1.0% of PO was used. After the pigment was made into a solid solution dispersion paste, it was added to the photopolymerizable resin and mixed with stirring. After filtering the obtained mixture, it was spin-coated on a transparent substrate to a thickness of 2 μm. Furthermore, after drying at 85 ° C. for 3 minutes, ultraviolet rays were irradiated at 80 mJ / cm ² , and development was performed with an alkali developing solution to prepare color filters of Examples (III-1) to (III).

Further, color filters of Example (III-2) and Example (III-3) were prepared in the same manner except that the combination, blending amount, blending ratio and the like of the pigment were changed. In addition, color filters with increased transmittance over the entire region including the original red wavelength region were prepared, and Comparative Examples (III-1) to (III-3) were prepared, and light only in the original red wavelength region was transmitted. A filter was prepared as described above, and the filter was designated as Conventional Example III.

FIGS. 28 to 30 show examples (III-1) to
The shape of the spectral transmission spectrum of each red filter of (III-3) is shown. Comparative Examples (III-1) to (III-3)
FIGS. 31 to 34 show the shapes of the spectral transmission spectra of the filter of Conventional Example III and FIGS. Further, Table 3 shows the chromaticity and luminance of the light transmitted through these color filters.

[0087]

[Table 3]

From the spectral transmission spectrum of the color filter of Example (III-1) shown in FIG. 28, the average value of the spectral transmittance in each region was obtained as follows. 90% or more from 580 nm to 780 nm 90% or more from 580 nm to 600 nm 90% or more from 510 nm to 560 nm Less than 1% 380 nm to 510 nm 10% or more 495 nm to 505 nm 15% or more Such a spectral spectrum makes the best use of the present invention. This is the shape of the spectrum.

Further, as shown in Table 3, the Example (III
The light transmitted through the color filter of -1) has a Y value of 45.
% And twice the brightness of the prior art, and the color is clear. FIG.
Examples (III-2) and (III-
From the spectral spectrum of the light transmitted through the color filter of 3), the average value of the spectral transmittance in each wavelength region was obtained as follows.

Example (III-2) Example (III-3) From 580 nm to 780 nm 90% or more 90% or more From 510 nm to 560 nm Less than 1% Less than 1% From 380 nm to 510 nm 10% or more 15% or more 495 nm to 505 nm Up to 5% or more 5% or more The average value of the spectral transmittance in the range from 580 to 600 nm was all 60% or more.

As described above, the color filters of the embodiment (III-2) and the embodiment (III-3) are different in the shape of the spectrum from 380 nm to 510 nm within the scope of the present invention. In these cases, as shown in Table 3, both the x and y values of the chromaticity coordinates were good, and a high Y value of 43% or more was obtained, and bright and clear red was obtained. I understand.

Next, the spectral transmission spectrum of the color filter of Comparative Example (III-1) is shown in FIG. Specifically, the average value of the spectral transmittance in each wavelength region is as follows.

From 580 nm to 780 nm 85% or more 580 nm to 600 nm less than 60% 510 nm to 560 nm 5% or more 380 nm to 510 nm 10% or more 495 nm to 505 nm 10% or more Thus, in Comparative Example (III-1) Is from 580 nm to 600 n, which is an important area for securing brightness.
Since the average value of transmittance up to m is small, as shown in Table 3, the Y value is only about half that of the present invention. Moreover,
From 510 nm to 560, which is the area where red clarity is impaired
Due to the large transmittance up to nm, the saturation has hardly improved.

In Comparative Example (III-2), an attempt was made to increase the Y value of the spectral spectrum of Comparative Example (III-1) without using the present invention, and the obtained results are shown in FIG. . In this case, as shown in FIG.
From 600 nm to 600 nm is about 40%, and the average transmittance from 510 nm to 560 nm is 1%.
It was about 0%.

However, as shown in Table 3, the increase in the Y value was only about 2%, and the saturation was so low that it could not be used as a red color filter. FIG. 33 shows the spectral transmission spectrum of the filter of Comparative Example (III-3). As shown in FIG.
The average value of the transmittance from m to 780 nm is 90% or more, and the range from 570 nm to 600 nm is 95%.
As described above, a high Y value of 52.2% is obtained. However, the average value in the range from 380 nm to 560 nm, which is a region where the color is adjusted in balance with other regions, is less than 1%.

For this reason, as shown in Table 3, the Y value increases, but the saturation is greatly reduced, so that it cannot be used as a color filter for displaying red. In addition, the conventional example
FIG. 34 shows the spectral transmission spectrum of the color filter III.
Shown in As shown in FIG. 34, in the conventional example III, the average value of the transmittance in the range from 610 nm to 780 nm is 90% or more, but the average value in the range from 380 nm to 605 nm is less than 1%. Therefore, Table 3
As shown in FIG. 7, although the saturation is high, the Y value is extremely small at 18.4%, indicating that the brightness is insufficient. That is, since the color filter of Conventional Example III has a low light use efficiency, there is a problem that the power consumption is large when used in a color liquid crystal display device. It cannot be used for a liquid crystal display element that does not use a backlight, such as a reflective liquid crystal display element. According to this embodiment, it has a vivid color,
In addition, a color filter that transmits red light whose Y value indicating brightness is much larger than the conventional one was obtained.

[0097]

As described above, according to the present invention,
Provided is a color filter which can reduce the power consumption of a color liquid crystal display element and obtain a bright and clear color display. Further, according to the method of the present invention, it is possible to perform color display in which both light use efficiency and color saturation are compatible.
Such a color filter and a color display method are particularly effective for a reflective color liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a graph showing the results of a subjective color test.

FIG. 2 is a graph showing a relationship between a transmittance average value in a range of 380 nm to 440 nm, a change in chromaticity, and a change in luminous reflectance.

FIG. 3 is a graph showing a relationship between a transmittance average value in a range of 440 nm to 490 nm, a chromaticity change, and a luminous reflectance.

FIG. 4 is a graph showing a relationship between a transmittance average value in a range of 490 nm to 530 nm, a chromaticity change, and a luminous reflectance.

FIG. 5 is a graph showing a relationship between an average value of transmittance in a range of 530 nm to 590 nm, a change in chromaticity, and a luminous reflectance.

FIG. 6 is a graph showing a relationship between an average transmittance value in a range of 590 nm to 650 nm, a chromaticity change, and a luminous reflectance.

FIG. 7 is a graph showing a relationship between an average value of transmittance in a range of 650 nm to 780 nm, a change in chromaticity, and a luminous reflectance.

FIG. 8 is a graph showing a relationship between an average transmittance and a luminous reflectance in a range of 480 nm to 600 nm.

FIG. 9 is a graph showing the relationship between the average transmittance and the luminous reflectance in the range of 510 nm to 560 nm.

FIG. 10 is a graph showing a relationship between a transmittance average value in a range of 430 nm to 460 nm and a change in chromaticity.

FIG. 11 is a graph showing the relationship between the average transmittance and the luminous reflectance in the range of 580 nm to 780 nm.

FIG. 12 is a graph showing a relationship between an average transmittance value in a range of 580 nm to 600 nm, a chromaticity change, and a luminous reflectance.

FIG. 13 is a graph showing a relationship between an average transmittance value in a range of 510 nm to 560 nm, a chromaticity change, and a luminous reflectance.

FIG. 14 is a graph showing a relationship between an average transmittance value in a range of 380 nm to 510 nm, a chromaticity change, and a luminous reflectance.

FIG. 15 is a diagram showing a spectral spectrum shape of blue by the color filter of Example (I-1).

FIG. 16 is a diagram showing a spectral spectrum shape of blue by a color filter of an example (I-2).

FIG. 17 is a diagram showing a spectral spectrum shape of blue by a color filter of an example (I-3).

FIG. 18 is a diagram showing a blue spectral spectrum shape by the color filter of Comparative Example I.

FIG. 19 is a diagram showing a blue spectral spectrum shape by the color filter of Conventional Example I.

FIG. 20 is a diagram showing a spectral spectrum of an RGB color filter of Example (I-4).

FIG. 21 shows a voltage-transmittance curve of a liquid crystal display element.

FIG. 22 is a diagram showing a blue spectral spectrum shape according to Example (I-4).

FIG. 23 is a diagram showing a green spectral spectrum shape by the color filter of Example (II-1).

FIG. 24 is a diagram showing a green spectral spectrum shape by the color filter of Example (II-2).

FIG. 25 is a view showing a green spectral spectrum shape by the color filter of Example (II-3).

FIG. 26 is a diagram showing a green spectral spectrum shape by the color filter of Comparative Example II.

FIG. 27 is a diagram showing a green spectral spectrum shape by the color filter of Conventional Example II.

FIG. 28 is a view showing a red spectral spectrum shape by the color filter of Example (III-1).

FIG. 29 is a diagram showing a red spectral spectrum shape by the color filter of Example (III-2).

FIG. 30 is a diagram showing a red spectral spectrum shape by the color filter of Example (III-3).

FIG. 31 is a diagram showing a red spectral spectrum shape by the color filter of Comparative Example (III-1).

FIG. 32 is a diagram showing a red spectral spectrum shape by the color filter of Comparative Example (III-2).

FIG. 33 is a diagram showing a red spectral spectrum shape by the color filter of Comparative Example (III-3).

FIG. 34 is a view showing a red spectral spectrum shape by the color filter of Conventional Example III.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G02B 5/22 G02B 5/20 G02F 1/1335 505 G09F 9/00 321

Claims (4)

(57) [Claims] 1. A wavelength range of transmitted light when a target color is displayed, a first wavelength range used for displaying a target color, a wavelength range of another color used for displaying another color, It is divided into three types of wavelength regions, a second wavelength region that does not reduce the saturation and a third wavelength region that is used for displaying other colors and reduces the saturation of the target color. The average value of the spectral transmittance in the wavelength range is T ₁ > T ₂ > T ₃ (where T ₁ , T _2, and T ₃ are the first wavelength range, the second wavelength range, and the third wavelength range, respectively) A color filter that satisfies the following relationship: the average value of the spectral transmittance in the wavelength region), the target color is blue, the first wavelength region is 380 nm to 490 nm, and the second wavelength region is 490 nm to 5 nm.
30 nm, third wavelength range from 530 nm to 650 n
m, and the average value of the spectral transmittance in the first wavelength region is 6
0% or more, and the average value of the spectral transmittance in the second wavelength region is 50
% To 90%, the average value of the spectral transmittance in the third wavelength region is 30% or less, and 650 nm to 780.
The average value of the spectral transmittance in the range of nm is 10% or more and 590.
The average value of the spectral transmittance in the range of 650 nm to 650 nm is 15%
A color filter characterized by the following. 2. A wavelength region of transmitted light when a target color is displayed, a first wavelength region used for displaying a target color, a wavelength region used for displaying another color, and a target color. It is divided into three types of wavelength regions, a second wavelength region that does not lower the saturation and a third wavelength region that is used for displaying other colors and that lowers the saturation of the target color. The average value of the spectral transmittance in the wavelength region is T ₁ > T ₂ > T ₃ (where T ₁ , T _2, and T ₃ are the first wavelength region, the second wavelength region, and the third wavelength region, respectively) A color filter that satisfies the following relationship: the average value of the spectral transmittance in the wavelength region), the target color is green, the first wavelength region is 480 nm to 600 nm, and the second wavelength region is 380 nm to 4 nm.
25 nm and 605 nm to 780 nm, and the third wavelength region is 430 nm to 460 nm.
And the average value of the spectral transmittance in the first wavelength region is 65
% Or more, and the average value of the spectral transmittance in the third wavelength region is 10%.
And in the second wavelength region, the following equation (1)
And (2) _{0.1T 480-500} ≦ T ₄₀₀ ≦ _{1.6T 480-500} (1) _{0.05T 580-600} ≦ T ₆₃₀ ≦ 0.7T _580-600 (2) (However, T ₄₀₀ and T ₆₃₀ is 400n each
m and the average value of the spectral transmittance at 630 nm, and T _{480 to 500} and T _{580 to 600} are 48
The average value of the spectral transmittance from 0 nm to 500 nm and the average value of the spectral transmittance in the range of 580 nm to 600 nm. ) And 510 to 56
A color filter, wherein the average value of the spectral transmittance in a range of 0 nm is 80% or more. 3. A wavelength region of transmitted light when a target color is displayed, a first wavelength region used for displaying the target color, a wavelength region used for displaying another color, and It is divided into three types of wavelength regions, a second wavelength region that does not lower the saturation and a third wavelength region that is used for displaying other colors and that lowers the saturation of the target color. The average value of the spectral transmittance in the wavelength region is T ₁ > T ₂ > T ₃ (where T ₁ , T _2, and T ₃ are the first wavelength region, the second wavelength region, and the third wavelength region, respectively) Is the average value of the spectral transmittance in the wavelength region), the target color is red, the first wavelength region is 600 to 780 nm, and the second wavelength region is 380 to 510 nm.
And the third wavelength region is 510-560n
m, and the average value of the spectral transmittance in the first wavelength region is 8
5% or more, the average value of the spectral transmittance in the second wavelength region is 10
% Or more, an average value of spectral transmittance in the third wavelength region is less than 5%, and 580 to 600 nm is 60% or more. 4. The method according to claim 1, wherein
Reflective type characterized by having a color filter
Liquid crystal display element.