JPH0527229A - Color liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a color liquid crystal display device which is thin, reduced in weight, and less in power consumption by providing a color filter whose pigment dispersion quantity is optimized. CONSTITUTION:A color filter which is specified to 5-25% pigment dispersion and 1.5-2.5mu film thickness is used as a color filter 138 formed below one transparent electrodes 133 or 134. Further, the display device consists of a display panel constituted by providing >=1 birefringent film 121 to any one of polarizing plates 111 and 112 arranged across the panel and a back light which has a fluorescent lamp 151 arranged in the length direction of a photoconductor 152. Consequently, the color display device which is thin, reduced in weight, and less in powder consumption is obtained and a bright, high-contrast display is obtained.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a super twisted nematic type color liquid crystal display device, and particularly to a thin type,
The present invention relates to a color liquid crystal display device suitable for a notebook personal computer, which requires light weight, low power consumption, and bright color display.

2. Description of the Related Art A conventional super twisted nematic black and white and color liquid crystal display device (hereinafter referred to as B / W ST
N-LCD and color STN-LCD)
64-519, JP 64-23224 and JP 1-
In a liquid crystal display device having a twisted helical structure of 200 to 300 degrees as disclosed in Japanese Patent No. 105217, a so-called single layer type B using a birefringent film as a means for eliminating unnecessary coloring and enabling black and white display. / W STN-LCD, and a single-layer color STN-LCD is proposed which is a combination of the single-layer B / W STN-LCD and a color filter. These proposed monolayer black and white STN liquid crystal display elements are widely used in word processors, notebook type personal computers and the like. However, the single-layer color STN liquid crystal display device is currently used only in a high-end model of a laptop personal computer. In recent years, applications have expanded with the increase in the amount of information, and at a low price that is widely used in notebook personal computers and the like,
In addition, there is an increasing demand for development of a thin, lightweight, low power consumption type color STN liquid crystal display device having excellent portability. However, since the conventional color STN liquid crystal display element has a low transmittance of 2 to 3%, the brightness at the time of intended white display is low.
High brightness (3000 nit) to obtain (60 to 90 nit)
You need a backlight. From this, the liquid crystal module is as thick as about 30 mm and weighs 1200 g.
It is relatively heavy and consumes as much as 15W and is far from a thin, lightweight, and low power consumption liquid crystal module. The specifications required for a color STN liquid crystal display device applicable to a notebook personal computer are I was not satisfied.

The above prior art does not consider a thin, lightweight, low power consumption, and bright color liquid crystal display device compatible with a notebook personal computer, and has a target brightness. To get
In terms of thickness, weight, and power consumption, it was within the range that a color liquid crystal display device compatible with laptop personal computers could be achieved. An object of the present invention is to make a liquid crystal display device having high transmittance, high contrast, uniformity of in-plane brightness, and thinness of a backlight in consideration of light utilization efficiency in consideration of spectral characteristics of a color filter and smoothness of the color filter. It is possible to realize a thin, lightweight and low power consumption color liquid crystal display device compatible with a notebook personal computer by reducing the power consumption and reducing the power consumption.

[Means for Solving the Problems]
A so-called single-layer liquid crystal display element that performs phase compensation using a retardation film having a birefringence property against unnecessary coloring due to the constitutional conditions of a twisted nematic liquid crystal display element, and one electrode substrate has spectral characteristics and Thinness, lightness, and lightness can be achieved by using a color liquid crystal display element with a high transmittance equipped with a color filter optimized for both the smoothness and the amount of dispersion of the pigment and an edge light type backlight whose light reflectance changes continuously. And to achieve a low power consumption type color liquid crystal module.

In the super twisted nematic liquid crystal display device, at least one of the background and the display section is colored. At least one of the background and the display portion is subjected to phase correction by using a phase difference film having birefringence to achieve black and white display, and the scanning electrode substrate side or the signal electrode substrate side. The liquid crystal display element is configured by arranging a color filter that balances spectral characteristics such as balance of brightness and color purity and white balance by optimizing the amount of pigment dispersion on either Rate, high contrast,
Moreover, a thin and lightweight color liquid crystal display device can be achieved.
By achieving the high transmittance of the color liquid crystal display device, the brightness of the backlight can be reduced by the amount of the improvement in the transmittance, and a thin and low power consumption backlight can be used. From this, the light source is provided on the long side portion or the short side portion of the light guide, which has a thin thickness where the light reflectance continuously changes toward the central portion of the high transmittance color liquid crystal display element and the color liquid crystal display element. A thin, lightweight, and low power consumption type color liquid crystal module can be achieved by configuring the module with the edge-light type backlight arranged.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A color liquid crystal display device suitable for carrying out the present invention will be described in detail below with reference to the drawings. In this embodiment, the display scale is 640 (× 3) × 400 dots (pixel pitch: 0.27 mm, pixel size: 0.255 mm ×
A display device having a size of 0.255 mm and screen diagonal size: 8.0 inches will be mainly described. First, FIG. 1 is a sectional view showing the structure of a color liquid crystal display device of the present invention. As shown in the figure, the display device is roughly classified into a color liquid crystal display element 130.
And a backlight 150. In the figure, the color liquid crystal display device 130 includes upper and lower electrode substrates (material: soda lime glass, thickness: 0.7 mm) 131, 1
32, liquid crystal 140, birefringent film (manufactured by Nitto Denko: uniaxially stretched polycarbonate film) 121, 122, upper and lower polarizing plates (manufactured by Nitto Denko: G1220DU, transmittance: 40
%) 111, 112. The upper electrode substrate 131 has a black matrix (pigment type, thickness: 0.7 to 1.3 μm).
m) 137, color filter (pigment type, thickness: 1.5-
2.5 μm) 138, smoothing film (epoxy resin, thickness: 0.7 to 1.3 μm) 139, upper transparent electrode (IT
O, sheet resistance: 15Ω / □ 133, alignment film (polyimide resin, thickness: 0.07 to 0.13 μm) 136 is formed, while lower electrode substrate 132 has a lower transparent electrode ( ITO, sheet resistance: 15Ω / □, 134, insulating film (film material: SiO ₂ , thickness: 0.07 to 0.13 μm) 1
35 and an alignment film 136 are formed. The alignment film 136 on the upper and lower electrode substrates 131 and 132 is rubbed to form a spiral structure in which the liquid crystal (Merck mixed liquid crystal, liquid crystal layer thickness: 6 μm) 140 is twisted by 260 degrees between the upper and lower electrode substrates 131 and 132. did. Furthermore, the upper electrode substrate 1
The upper polarizing plate 111 is arranged on the side opposite to the color filter 138 on which the color filter 138 is formed, and the birefringent films 121 and 122 and the lower polarizing plate 112 are arranged on the opposite side where the lower electrode 134 of the lower electrode substrate 132 is formed. The figure shows the upper electrode substrate 13
Although the structure in which the color filter is formed is shown in FIG. 1, it is advantageous to form the color filter on the lower electrode substrate having a small number of electrodes in consideration of the ease of forming electrodes. However, in this case, it becomes difficult to align the color filters formed on the upper electrode and the lower electrode substrate when assembling the liquid crystal display element. The color liquid crystal display element 130 and the backlight unit 150 which is thin and has low power consumption are included. The backlight unit 150 is roughly classified into a light guide plate (material: acrylic, thickness: 3 mm) 151, a cold cathode tube (Matsushita: K-C240T4E72, tube diameter: 4 mm) 152, a reflection sheet.
(Dia foil made: W-400, thickness: 0.125 mm)
153, diffusion sheet (manufactured by Kimoto: D-204, thickness:
0.1 mm) 154, reflection sheet for cold cathode tubes (GR-38W made by Kimoto, thickness: 0.1 mm) 155, double-sided adhesive tape (No.500 made by Nitto Denko) 156, guide for cold cathode tubes (silicon rubber) 157, and a white reflective film (dispersant: titanium oxide, base material: polyester resin) 158. A pigment-dispersed black matrix 137 (width: 0.025 mm) formed by a photolithography method was arranged on the upper electrode substrate 111 at a pitch of 0.09 mm, and a pigment-dispersed color matrix formed by a printing method was formed thereon. A filter 138 was placed. This color filter 138
Is a melamine-epoxy resin with an organic pigment or an inorganic pigment dispersed, and the film thickness is from 1.5 μm to 2.5 μm.
The one set in the range of μm was used. The black matrix 137 is mainly made of an acrylic resin in which carbon is dispersed, and a film having a thickness in the range of 0.7 μm to 1.3 μm is used so that the transmittance is 2% or less. The pigment-type black matrix 13
By using 7, the conventional chromium (film thickness: 0.1
Compared with a color liquid crystal display device using a black matrix formed with a thickness of about μm), the surface reflected light can be significantly reduced. Further, in this embodiment, the color filter 13
8 was formed by the printing method under the lower substrate side transparent electrode 134 from the viewpoint of forming the electrodes 133 and 134, and the black matrix was formed by the photolithography method. It is desirable to form a black matrix by In order to form the black matrix by the printing method, it is necessary to form a high-precision alignment mark so that the overlay accuracy with the common electrode formed on the color filter can be obtained, or to obtain the mark with the same precision. It is necessary to devise such a method. In the color liquid crystal display device of the present invention, the thickness of the liquid crystal layer and its uniformity are important factors that affect the display characteristics of brightness, contrast and color specification range. In order to make the thickness of the liquid crystal layer uniform, it is desirable to form the color filter with the same smoothness as the upper and lower electrode substrates. In the color liquid crystal display device of the present invention, the dispersion amount of the pigment of the color filter or the spectral transmittance characteristic is specified so that the three characteristics of the color filter such as smoothness, color purity and transmittance are satisfied in a well-balanced manner. In addition, we have made it possible to use a backlight with a fluorescent discharge tube arranged on the side of the light guide, achieving a thin, lightweight and low power consumption. In the color liquid crystal display device of the present invention, the point is the pigment dispersion type color filter 138 formed by this printing method,
The dispersion amount of the pigment in the color filter was optimized by an experiment in consideration of the smoothness on the color filter 138, the color purity, the transmittance, and the balance of these three characteristics. FIG. 2 shows the relationship between the pigment dispersion amount, the transmittance, the contrast ratio, and the stimulation purity. As shown in the figure, the lower limits of the transmittance, the contrast ratio, and the stimulation purity are T = 5%, Cr = 10, and
It has been found that when Pr = 10% is set, the range of the pigment dispersion amount that satisfies all the three characteristics may be set in the range of approximately 25% to 5%. However, it is important to specify the thickness of the color filter at this time in the range of approximately 1.5 μm to 2.5 μm. That is, the spectral transmittance characteristic of the color filter is generally determined by the product of the amount of pigment dispersion and the film thickness of the color filter. Considering the balance among the three display characteristics of brightness, contrast, and color specification range, module thickness, and power consumption, it is preferable that the pigment dispersion amount be 23%.
To 8%, the thickness of the color filter is approximately 1.7μ
It has been found that it may be specified in the range of m to 2.3 μm. Therefore, in this embodiment, the color filter 138 in which the dispersion amount of the pigment is set to about 15% is arranged. FIG. 3 shows the spectral transmittance characteristics of the color filter 138 in which the pigment dispersion amount is approximately 15% and the color filter film thickness is approximately 2 μm, and the pigment dispersion amount used in the conventional laptop personal computer. The thickness of the color filter is about 30%, and the spectral transmittance characteristic of the color filter specified to be about 2 μm is shown. In the figure, 410 and 411 are red spectral characteristics, 420 and 421 are green spectral characteristics, and 43.
0,431 is the spectral characteristic of blue, but 410,42
Reference numerals 0 and 430 are color filters in which the pigment dispersion amount is specified to be about 15%, and reference numerals 411, 421 and 431 are color filters in which the pigment dispersion amount is specified to be about 30%. As shown in the figure, the transmittance in the wavelength region other than the intended color is increased to the contrary to the conventional one to improve the transmittance of the color filter, and the smoothness of the color filter is also compared to the conventional one. The point is that it is improved about 3 times. However,
The stimulation purity of the color filter of the present invention is slightly lower than that of a color filter having a pigment dispersion amount of about 30% used in a conventional laptop personal computer. Therefore, as compared with the conventional color filter, the color filter of the present invention is a light color filter. Note that in order to use such a light color filter, white balance using only the color filter, or
In the module configuration shown in (1), it is important to have a spectral transmittance characteristic in consideration of white / black balance in the combination of the color liquid crystal display element 130 and the backlight unit 150. In addition to the method described above, there is a method of arranging dichroic filters in stripes as a color filter satisfying the characteristics of high transmittance, high smoothness and high heat resistance. However, the color filter of this method has a drawback that it cannot be manufactured at a low cost because the forming method is complicated. Further, as another method, a phase compensating film having a different product of the refractive index and the thickness of the phase compensating film is formed in stripes corresponding to the column electrodes, and red, green and blue colors are formed by interference. There is a method to make it work in the same way as a filter. This method has the drawbacks that the method for forming the phase compensating film is complicated and expensive, and that the column electrodes and the phase compensating film need to be bonded together with high precision. Another method is to form a panel in which the liquid crystal layers have different thicknesses corresponding to the column electrodes so that the liquid crystal layers have different thicknesses. This method also has the drawback of complicating the panel formation. The above three methods are effective for obtaining a high transmittance panel, but in a color display device for a notebook personal computer, in addition to high quality display characteristics, low power consumption, and low price, It is an important factor, and is slightly inferior. Further, FIG. 4 shows a layout of the dummy color filters and the dummy electrodes. As shown in the figure, in this embodiment, in order to make the thickness of the liquid crystal layer 140 in the display area uniform, the dummy black matrix 137 and the color filter 1 which do not contribute to the display other than the display area are provided.
38 and the upper and lower electrodes 133 and 134 were arranged at the same pitch as the display area. Furthermore, as shown in the figure, the outermost colors of the dummy color filters on both sides of the display unit are
It was arranged so as to have a color other than red. Therefore, the number of dummy color filters and the number of dummy electrodes are arranged so as to be different between the right side and the left side of the display section. With such a color filter arrangement, especially when the color filter 138 is formed on the lower electrode substrate 132 having a small number of electrodes,
Even if some deviation occurs when the upper and lower electrode substrates 131 and 132 are assembled, it is advantageous in that unnecessary display of colors that are easily visible can be prevented. Therefore, more preferably, in the arrangement of the dummy color filters, it is desirable that the color of the dummy color filters on the right side and the left side of the display section and on both sides be blue. In the present invention, the pigment dispersion amount of the color filter is specified in order to achieve both smoothness on the color filter and high transmittance. However, the uniformity of the liquid crystal layer thickness equivalent to that of the monochrome liquid crystal display element is further specified. In order to obtain the above, the configuration is such that a smoothing film is formed on the color filter. FIG. 5 shows the positional relationship between the smoothing film, the color filter, and the upper and lower transparent electrodes in the embodiment of the present invention. In the figure, the color filter is arranged under the lower transparent electrode, and the smoothing film 139 is formed only on the color filter 138 including the dummy black matrix and the dummy color filter on the lower electrode substrate 132. The lower transparent electrode 134 was formed directly on the glass substrate 132 without providing the smoothing film 139 under the terminal portion of the lower transparent electrode 134. In this embodiment, thinning,
A tape carrier package was used for the liquid crystal driving LSI in order to reduce the weight and reduce the area other than the display section. To connect the tape carrier package to the glass substrate, thermocompression bonding is performed using an adhesive having conductivity anisotropy. The general connection conditions of this kind are as follows: heating temperature is about 170 degrees and pressure is 2
20kg / cm ² to 40kg / cm ²
Seconds. When connecting under such heating and pressurizing conditions, if a smoothing film is formed under the terminal portion, disconnection or the like will occur at the terminal portion, and reliability will be significantly impaired. Next, an important point in the color liquid crystal display device of the present invention is the positional relationship of the optical axes between the optical members. FIG. 6 is a definition diagram of angles α, β, γ, and θ showing the arrangement relationship of the optical axes between the optical members. In the figure, the angle α ₁ is the optical axis 123 of the upper birefringent film and the liquid crystal alignment direction 22 of the upper electrode substrate.
The included angle of 0, the angle α ₂ is the optical axis 12 of the lower birefringent film.
4 and the liquid crystal alignment direction 220 of the upper electrode substrate, the angle β ₁
Is the angle between the optical axis 123 of the upper birefringent film and the absorption axis 240 of the upper polarizing plate, and the angle β ₂ is the angle between the optical axis 124 of the lower birefringent film and the absorption axis 240 of the upper polarizing plate, the angle γ.
Is the angle between the liquid crystal alignment direction 230 of the lower electrode substrate and the absorption axis 250 of the lower polarizer, and the angle θ is the counterclockwise direction from the liquid crystal alignment direction 220 of the upper electrode substrate to the liquid crystal alignment direction 230 of the lower electrode substrate. Is defined as the angle of. In this embodiment, the twist angle θ of the liquid crystal molecules is 260 degrees, the product Δn · d of the refractive index anisotropy Δn of the liquid crystal and its thickness d is about 0.83 μm, and the birefringent film 211, A uniaxially stretched polycarbonate film manufactured by Nitto Denko was used as 212. The product Δn · d of the refractive index anisotropy Δn and the thickness d of the uniaxially stretched polycarbonate films 211 and 212 is about 0.40 μm. However, this uniaxial polycarbonate film 21
The product of the refractive index anisotropy Δn of 1, 212 and its thickness d Δn
The d is measured by the Senarmont method, and the measurement wavelength is 633 nm.
Is. In this embodiment, the angle α ₁ is about 30 to 40 degrees, α ₂ is about 0 to 10 degrees, β ₁ is about 5 to 15 degrees, and β ₂ is about 45 to 55 degrees.
The degree and γ were specified to be about 40 to 50 degrees. By configuring the color liquid crystal display element 130 with the optical element arrangement as described above, when the voltage applied to the liquid crystal layer 140 via the upper and lower transparent electrodes 133 and 134 is less than or equal to the threshold value, the optical failure is prevented. When the light is transmitted, that is, black and the voltage exceeds a certain threshold, light transmission, that is, color display can be realized. Next, FIG. 7 shows the structure of the backlight, which is an important point along with the color filter. In the figure, 15
1 is a cold cathode tube, 152 is a light guide plate, 153 is a diffusion sheet,
154 is a reflection sheet, 155 is a reflection sheet for cold cathode tubes,
Reference numeral 156 is a double-sided adhesive tape for fixing the reflection sheet for cold cathode fluorescent lamps, 157 is a guide for cold cathode fluorescent discharge tubes, 15
8 is a white reflective film. Here, the cold cathode tubes 151 have a diameter of 4.0 mm and a length of 235 mm, and two lights are arranged in the long side direction of the light guide plate 152. The light guide plate 152 has a thickness of 3 mm.
The acrylic plate and reflective sheet 154 are 0.125 mm thick
Polyester sheet, reflective sheet for cold cathode tube 155 is a 0.125 mm thick polyester sheet with silver evaporated, double-sided adhesive tape 156 is a non-woven fabric with acrylic adhesive, and cold cathode tube guide 157 is silicon. The white reflective film 158 made of rubber or phenol resin is a polyester ink containing titanium oxide as a main component or an acrylic ink containing titanium oxide as a main component. At this point, since a cold cathode tube having a tube diameter of 3.0 mm has not been developed, the cold cathode tube 1 having a tube diameter of 4.0 mm is used in this embodiment.
Although 51 and the light guide plate 155 are made of a combination using an acrylic plate having a thickness of 3 mm, the cold cathode tube 151 whose diameter is equal to or smaller than the thickness of the light guide plate is efficiently used. It is desirable to do. Further, the backlight having the features of thinness, light weight, low power consumption, and high brightness shown in the same figure has a white reflective film 158 continuously formed from the cold cathode tube 151 side toward the central portion on the back surface of the light guide plate 152. It is arranged such that the light reflectance changes, so that the in-plane brightness can be made uniform. In order to form the white reflective film 158 so that the light reflectance changes continuously, the white reflective film 15
There is a method of changing the density without changing the area, shape or shape of No. 8. The brightness distribution characteristic in the short side direction in the vicinity of the central portion of the backlight used in this example is 85% or more when the variation in brightness is defined as the minimum in-plane brightness / the maximum in-plane brightness. Is also small. Further, the average brightness in the plane is 1000 nit (tube current: 5 mA, power consumption: 6 W
(Including inverter)). From the point of view of a color display for a notebook PC, it is desirable to reduce power consumption as much as possible so that the battery can be driven for a long time. Therefore, it is more preferable for the color display for a notebook PC to set the average brightness of the backlight to about 600 nits and to reduce the power consumption to 5 W or less. FIG. 8 shows a block diagram of the color liquid crystal display device of the present invention. In the figure, 130 is a color liquid crystal display element, 810 is a scanning side drive circuit, 820 is a signal side drive circuit, and 830 is a control circuit for controlling the scanning side drive circuit and the signal side drive circuit. In this embodiment, in order to reduce the size and weight,
A tape carrier package was used for the scanning side drive circuit 810 and the signal side drive circuit 820. This tape carrier package uses a string-shaped liquid crystal driving LSI chip, and is generally called a micro tape carrier package. In this embodiment, a polyimide tape having a width of 35 mm can be used, and a tape carrier package having a length of about 11 mm has been developed and used. Further, in the configuration of the display device shown in the figure, as a mounting method other than the above, the tape carrier package is bent by using the relatively large curvature of the cold cathode tube 151 of the backlight unit 150 shown in FIG. Used
We also implemented a method to minimize the parts other than the display. In the figure, 130 is a liquid crystal display element, 151 is a cold cathode tube,
Reference numeral 152 is a light guide plate, 153 is a diffusion sheet, 154 is a reflection sheet, 155 is a reflection sheet for cold cathode fluorescent tubes, 156 is a double-sided adhesive tape for fixing a reflection sheet for cold cathode fluorescent discharge tubes, 157 is a guide for cold cathode tubes, 158. Is a white reflective film, 160 is a tape carrier package that does not remove the base film of the bent portion, 161 is an input signal printed board for controlling the tape carrier package, 1
Reference numeral 62 is a liquid crystal driving LSI chip. This method can minimize the area other than the display area, and can significantly improve the reliability as compared with the conventional method using the tape carrier package in which the base film of the bent portion is removed. Next, the display characteristics of the color liquid crystal display device of the present invention will be described. First, in FIG.
The luminance-applied voltage characteristic when viewed from the front during / 400 duty time division driving is shown. In the figure, 91
0 is the luminance-applied voltage characteristic in the white display state, and 920 is the luminance-applied voltage characteristic in the black display state. In addition,
The brightness-voltage characteristics of this liquid crystal display panel shown in the same figure are the characteristics on the front side of the panel, but the brightness during white display is
The nit and the contrast ratio are 12: 1, and a display that is easy to see can be achieved. FIG. 11 shows the contrast ratio characteristic during 1/400 duty time division driving. In the figure, 1010 shows the contrast ratio characteristic when viewed from above and below the panel, and 1020 shows the contrast ratio characteristic when viewed from the left and right direction with respect to the panel. As shown in the figure, the contrast ratio when viewed from the front of the panel is about 13: 1, and the maximum contrast ratio is about 25: 1 when viewed from the upper 20 degrees in the vertical direction. further,
In the range where the contrast ratio is 5: 1 or more, the horizontal direction is ± 4
0 degree and ± 40 degrees in the vertical direction. 1/40 in FIG.
The color range characteristics at the time of 0 duty time division driving are shown. In the figure, 1110 is a color cathode ray tube, 11
Reference numeral 20 is a color specification range of the display device. As shown in the figure, the color specification range 1120 of this embodiment is slightly narrower than the color specification range 1110 of the color CRT. However, the color liquid crystal display device of the present embodiment has display characteristics that are thin, light weight, low power consumption, bright, high contrast, and wide viewing angle, and are much easier to see than the conventional liquid crystal display device.
As for the response speed, in order to make a display device suitable for a personal computer, a system using a high-speed response liquid crystal material,
200ms was achieved by any of the methods of reducing the thickness of the liquid crystal layer, which enabled the use of a mouse. Next, another embodiment will be described in which the basic structure is the same as that shown in FIG. 1, but the focus is on the ease of manufacturing the liquid crystal display element. FIG. 13 is a sectional view showing the structure of the color liquid crystal display device. In the figure, the color liquid crystal display device 130 includes upper and lower electrode substrates (material: soda lime glass, thickness:
0.7 mm) 131, 132, liquid crystal 140, birefringent film (Nitto Denko: uniaxially stretched polycarbonate film) 121, 122, upper and lower polarizing plates (Nitto Denko: G12)
20DU, transmittance: 40%) 111, 112. The upper electrode substrate 131 has a black matrix (pigment type, thickness: 0.7 to 1.3 μm) 137, a color filter.
(Pigment type, thickness: 1.5 to 2.5 μm) 138, smoothing film (epoxy resin, thickness: 0.7 to 1.3 μm) 139,
Upper transparent electrode (ITO, sheet resistance: 15Ω / □) 13
3, alignment film (polyimide resin, thickness: 0.07 to 0.1)
3 μm) 136 is formed, while the lower electrode substrate 132 has a lower transparent electrode (ITO, sheet resistance: 15Ω).
/ □) 134, insulating film (film material: SiO ₂ , thickness: 0.0
7 to 0.13 μm) 135 and an alignment film 136 are formed. Alignment film 1 on the upper and lower electrode substrates 131 and 132
36 is rubbed, and liquid crystal (mixed liquid crystal made by Merck, liquid crystal layer thickness: 6 μm) 14 is provided between the upper and lower electrode substrates 131 and 132.
A spiral structure was formed in which 0 was twisted by 240 degrees. Further, on the opposite side of the upper electrode substrate 131 on which the color filter 138 is formed, the birefringent films 121 and 122 and the upper polarizing plate 111, and on the opposite side of the lower electrode substrate 132 on which the lower electrode 134 is formed. The lower polarizing plate 112 was arranged. The color liquid crystal display device 130 and the thin, low power consumption type backlight unit 150 are used. The backlight unit 150 is roughly classified into a light guide plate (material: acrylic, thickness: 3 mm) 151, a cold cathode tube (Matsushita: K-C240T4E72, tube diameter: 4 mm) 152, a reflection sheet (dia foil: W). -400, thickness: 0.125mm) 1
53, diffusion sheet (manufactured by Kimoto: D-204, thickness: 0.
1 mm) 154. The upper electrode substrate 11
A pigment-dispersed black matrix 137 formed by a photolithography method was arranged on No. 1 at a pitch of 0.1 mm, and a pigment-dispersed color filter 138 formed by a printing method was arranged thereon. The color filter 138 is made by dispersing an organic pigment or an inorganic pigment in a melamine epoxy resin, and has a film thickness of 1.5 μm to 2.5 μm.
The value set in the range of was used. Further, the black matrix 137 is mainly an acrylic resin in which carbon is dispersed, and a film having a film thickness set in the range of 0.7 μm to 1.3 μm in order to make the transmittance of 2% or less was used. In this embodiment, the twist angle θ of liquid crystal molecules is 240.
Degree, product Δ of refractive index anisotropy Δn of liquid crystal 140 and its thickness d
n · d is about 0.775 μm, and the birefringent film 2
Nitto Denko uniaxially stretched polycarbonate films were used as 11 and 212. The product Δn · d of the refractive index anisotropy Δn and the thickness d of the uniaxially stretched polycarbonate films 211 and 212 is about 0.35 μm. FIG. 14 shows the angles α, β, γ showing the optical elements in this embodiment.
As shown in the figure, the liquid crystal alignment direction 220 of the upper electrode substrate
The angle α ₁ between the optical axis 213 of the uniaxial polycarbonate film 121 closer to the upper electrode substrate 131 is about 6
The angle α ₂ formed by the liquid crystal alignment direction 220 of the upper electrode substrate and the optical axis 124 of the uniaxial polycarbonate film 122 farther from the upper electrode substrate 131 is about 75 to 8 degrees.
5 degrees, absorption axis 240 of upper polarizing plate and upper electrode substrate 131
The angle β ₁ formed by the uniaxial polycarbonate film 121 closer to the optical axis 123 is about 50 to 60 degrees, and the optical axis of the uniaxial polycarbonate film 122 farther from the absorption axis 240 of the upper polarizing plate and the upper electrode substrate 131. The angle β ₂ formed with 124 is about 15 to 25 degrees, and the absorption axis 25 of the lower polarizing plate
The angle γ between 0 and the liquid crystal alignment direction 230 of the lower electrode substrate is about 40 to 50 degrees. The other configurations and the display characteristics such as the contrast ratio, the color range characteristics, and the response speed are almost the same as those of the above-described embodiment.

According to the present invention, it is possible to achieve a thin, light-weight, low-power-consumption, bright, and high-contrast color liquid crystal display device, and in particular, a notebook type personal computer having excellent portability. A suitable color liquid crystal display device can be achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a basic configuration of a color liquid crystal display device according to the present invention.

FIG. 2 is a diagram showing a relationship among a pigment dispersion amount and a panel transmittance, a contrast ratio, and a stimulus purity for specifying an optimum range of the pigment dispersion amount in the color filter of the color liquid crystal display device according to the present invention.

FIG. 3 is a diagram showing a spectral transmittance characteristic of a color filter of a color liquid crystal display device according to the present invention.

FIG. 4 is a diagram showing an arrangement of dummy color filters and dummy electrodes of a color liquid crystal display device according to the present invention.

FIG. 5 is a sectional view of a panel showing an arrangement of smoothing layers on a color filter of a color liquid crystal display device according to the present invention.

FIG. 6 is a diagram showing definitions of angles α, β, γ which are optical elements between respective constituent members of the color liquid crystal display device in the present specification.

FIG. 7 is a diagram showing a configuration of a backlight of a color liquid crystal display device according to the present invention.

FIG. 8 is a block diagram showing a drive circuit configuration of a color liquid crystal display device according to the present invention.

FIG. 9 is a module of a color liquid crystal display device according to the present invention.
FIG.

FIG. 10 shows the luminance of the color liquid crystal display device according to the present invention.
The figure which shows a voltage characteristic.

FIG. 11 is a diagram showing the angle characteristic of the contrast ratio of the color liquid crystal display device according to the present invention.

FIG. 12 is a diagram showing a color specification range of a color liquid crystal display device according to the present invention.

FIG. 13 is a sectional view showing the structure of a color liquid crystal display device according to another embodiment of the present invention.

FIG. 14 is a view showing angles α, β, γ which are optical elements between respective constituent members in another embodiment of the present invention.

[Explanation of symbols]

111 ... Upper polarizing plate, 112 ... Lower polarizing plate, 121 ... Upper birefringent film, 122 ... Lower birefringent film,
123 ... Optical axis of upper birefringent film, 124 ... Optical axis of lower birefringent film, 130 ... Liquid crystal display element, 13
1 ... Upper electrode substrate of liquid crystal display element, 132 ... Lower electrode substrate of liquid crystal display element, 133 ... Upper transparent electrode, 134 ... Lower transparent electrode, 135 ... Insulating film, 136 ... Alignment film, 137
... Black matrix, 138 ... Color filter, 13
9 ... Smoothing film, 140 ... Liquid crystal, 141 ... Spacer, 14
2 ... Adhesive, 150 ... Backlight unit, 151 ...
Cold cathode tube, 152 ... Light guide body, 153 ... Reflective sheet, 15
4 ... Diffusion sheet, 155 ... Cold cathode tube reflection sheet, 15
6 ... Double-sided adhesive tape, 157 ... Lamp guide, 158 ...
White reflective film, 160 ... Bending tape carrier package, 161 ... Printed board, 162 ... Liquid crystal driving LSI
Chip, 220 ... Liquid crystal alignment direction of upper electrode substrate, 230
... Liquid crystal alignment direction of lower electrode substrate, 240 ... Absorption axis of upper polarizing plate, 250 ... Absorption axis of lower polarizing plate, 410, 411
… Red spectral characteristics, 420, 421… Green spectral characteristics, 4
30, 431 ... Blue spectral characteristics, 810 ... Scanning side driving circuit, 820 ... Signal side driving circuit, 830 ... Control circuit, 91
0 ... Luminance-applied voltage characteristic in white display state, 920 ...
Luminance-applied voltage characteristic in black display state, 1010 ... Contrast ratio characteristic in vertical direction of panel, 1020 ... Contrast ratio characteristic in horizontal direction of panel, 1110 ... Color range in color CRT, 1120 ... Color in display device of the present invention range.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ken Saito             Hitachi, Ltd. 3300 Hayano, Mobara-shi, Chiba             Mobara Factory

Claims (30)

[Claims] 1. A nematic liquid crystal having a positive dielectric anisotropy, to which an optical rotatory substance is added, is sandwiched between electrode substrates provided with a color filter in either one of a pair of upper and lower surfaces facing each other. In a twisted nematic type color liquid crystal display device including a liquid crystal element having a spiral structure twisted in the thickness direction, a pair of polarizing plates sandwiching the liquid crystal element and a backlight, a high transmittance color filter is used as a color filter. A color liquid crystal display device comprising a filter or a light color filter. 2. As a liquid crystal display element, a nematic liquid crystal element sandwiched between electrode substrates is provided with a twisted spiral structure within a range of 180 to 270 degrees in the thickness direction, and the liquid crystal element is provided to sandwich the liquid crystal element. A pair of polarizing plates, and a color liquid crystal display device comprising a backlight and a super twisted nematic liquid crystal display device in which one or more birefringent films are arranged on at least one of the polarizing plate and the liquid crystal device. A color liquid crystal display device comprising a high transmittance color filter or a light color filter as a color filter. 3. A liquid crystal display device, wherein a nematic liquid crystal sandwiched between electrode substrates has a twisted spiral structure in the range of 180 to 270 degrees in the thickness direction, and the liquid crystal device is sandwiched. A pair of polarizing plates, and a color liquid crystal display device comprising a backlight and a super twisted nematic liquid crystal display device in which one or more birefringent films are arranged on at least one of the polarizing plate and the liquid crystal device. , High transmittance color filter,
Alternatively, a color liquid crystal display device is characterized in that a light color filter and a black matrix are formed on a column (column side) electrode substrate side. 4. A liquid crystal display element, wherein a nematic liquid crystal element sandwiched between electrode substrates has a twisted spiral structure within a range of 180 to 270 degrees in the thickness direction, and the liquid crystal element is sandwiched. A pair of polarizing plates, and a color liquid crystal display device comprising a backlight and a super twisted nematic liquid crystal display device in which one or more birefringent films are arranged on at least one of the polarizing plate and the liquid crystal device. A color liquid crystal display device characterized in that a high-transmittance color filter or a light-color filter, a black matrix, and a transparent electrode that does not contribute to display are formed in a portion other than the display portion. 5. As a high transmittance color filter or a light color filter, a dispersion amount of a dye or a pigment is set to 25% or less, a film thickness is set in a range of 1.5 μm to 2.5 μm, or a color other than a desired color is used. 5. The color liquid crystal display device according to any one of claims 1 to 4, wherein the color liquid crystal display device has a spectral transmittance characteristic such that the spectral transmittance in the wavelength region is at least 5% or more. 6. A high transmittance color filter or a light color filter having a dispersion amount of a dye or a pigment of 5% to 25.
0%, set the film thickness in the range of 1.5 μm to 2.5 μm, or set the spectral transmittance characteristics such that the spectral transmittance in the wavelength range other than the desired color is in the range of 5% to 40%. The color liquid crystal display device according to claim 1, 2, 3, or 4. 7. The most suitable range for a high transmittance color filter or a light color filter is a dye or pigment dispersion amount of 8% to 23.0% and a film thickness of 1.7 μm to 2.
The spectral transmittance characteristic is set to a range of 3 μm or has a spectral transmittance characteristic such that the spectral transmittance in a wavelength region other than a desired color is in a range of 8% to 37%. 3. The color liquid crystal display device according to 3 or 4. 8. A color liquid crystal display device according to claim 1, wherein a pigment-dispersed color filter is used as the high transmittance color filter or the light color filter and the black matrix. 9. A pigment-dispersed color filter containing a thermosetting resin, an organic pigment or an inorganic pigment, and a dispersion aid as a main component is used as the high transmittance color filter or the light color filter and the black matrix. The color liquid crystal display device according to claim 1, 2, 3, or 4. 10. A pigment-dispersed color filter containing a thermosetting resin, an organic pigment or an inorganic pigment, and a dispersion aid as a main component, wherein the particle diameter of the organic pigment or the inorganic pigment is 1 μm or less. Item 5. A color liquid crystal display device according to item 1, 2, 3, or 4. 11. The color liquid crystal display device according to claim 1, wherein a pigment dispersion type color filter is formed by a printing method as the high transmittance color filter or the light color filter. 12. The color according to claim 1, 2, 3, or 4, wherein a pigment-dispersed color filter is formed as a high-transmittance color filter or a light-color filter by an intaglio or letterpress offset printing method. Liquid crystal display device. 13. A high transmittance color filter or a light color filter, wherein the three primary colors of red, green and blue are arranged in a stripe pattern.
The color liquid crystal display device described in 1. 14. A high transmittance color filter comprising red,
5. The green and blue dichroic filters are arranged in a stripe pattern.
The color liquid crystal display device described in 1. 15. The black matrix and the reference mark are pigment-dispersed color filters formed by a photolithography method.
Or the color liquid crystal display device according to item 4. 16. A high-transmittance color filter or a light color filter other than the display section, a black matrix and a transparent electrode not contributing to the display, wherein the light color filter and the transparent electrode are arranged at the same pattern pitch as the display section. The color liquid crystal display device according to claim 1, 2, 3, or 4. 17. The arrangement order of the high-transmittance color filters or the light color filters of the portion other than the display portion is the same as the arrangement order of the display portion, and color filters other than red are arranged at the left and right ends of the display portion. The color liquid crystal display device according to claim 1, 2, 3, or 4. 18. An epoxy-based polymer film or a polyimide-based polymer film as a smoothing film disposed so as to cover the high-transmittance color filter or the light-color color filter other than the display part and the color filter part of the display part. 2. The color filter is formed only on the color filter portion.
3. The color liquid crystal display device according to 3 or 4. 19. A voltage which causes a black display or a white display to be externally applied to a transparent electrode arranged in a portion other than the display portion and not contributing to display. , 3 or 4, the color liquid crystal display device. 20. A nematic liquid crystal having a positive dielectric anisotropy and to which an optical rotatory substance is added is sandwiched between electrode substrates provided with a color filter in either one of a pair of upper and lower surfaces facing each other. A liquid crystal element having a twisted spiral structure in the range of 180 to 270 degrees in the thickness direction, a pair of polarizing plates provided with the liquid crystal element sandwiched therebetween, and at least one of the polarizing plate and the liquid crystal element. In a color liquid crystal display device comprising a backlight and a super twisted nematic liquid crystal display element in which one or more birefringent films are arranged, a cold cathode type fluorescent discharge tube or a hot cathode type fluorescent discharge tube as a backlight, a light guide plate , Diffusion sheet,
An edge light including a reflection sheet and a lamp reflection sheet, in which at least one cold cathode type fluorescent discharge tube or hot cathode type fluorescent discharge tube is arranged on at least one of the short side and the long side of the light guide plate. Type liquid crystal display device characterized by having a type backlight. 21. An edge light type backlight comprising a cold cathode type fluorescent discharge tube or a hot cathode type fluorescent discharge tube, a light guide plate, a diffusion sheet, a reflection sheet, and a lamp reflection sheet, and a white dot-like shape on the back surface of the light guide plate. 21. The color liquid crystal display device according to claim 20, further comprising a reflective film. 22. An edge light type backlight having a halftone dot-shaped white reflective film on the back surface of a light guide plate, wherein the arrangement density of the white reflective film is determined according to the distance from the light source,
21. The color liquid crystal display device according to claim 20, wherein the color liquid crystal display device is variable according to the amount of dispersion. 23. An edge light type backlight having a dot-shaped white reflective film on the back surface of a light guide plate so that the density increases according to the distance from a light source, wherein the white reflective film is formed by printing. 21. The color liquid crystal display device according to claim 20. 24. An edge light type backlight having a dot-shaped white reflective film on the back surface of a light guide plate so that the density increases according to the distance from a light source, in a cold cathode fluorescent discharge tube or a hot cathode type 21. The color liquid crystal display device according to claim 20, wherein at least one light source such as a fluorescent discharge tube is arranged on the long side of the light guide plate. 25. An edge light type backlight having a dot-shaped white reflective film on the back surface of a light guide plate so that the density increases according to the distance from a light source, the thickness of the light guide plate and cold cathode fluorescent discharge. 21. The tube diameter of the tube or the hot cathode fluorescent discharge tube or the like is substantially the same, or the tube diameter of the cold cathode fluorescent discharge tube or the hot cathode fluorescent discharge tube is smaller than the thickness of the light guide plate. The described color liquid crystal display device. 26. A nematic liquid crystal having a positive dielectric anisotropy and to which an optical rotatory substance is added is sandwiched between electrode substrates provided with a color filter in either one of a pair of upper and lower surfaces facing each other. A liquid crystal element having a twisted spiral structure in the range of 180 to 270 degrees in the thickness direction, a pair of polarizing plates provided with the liquid crystal element sandwiched therebetween, and at least one of the polarizing plate and the liquid crystal element. A color liquid crystal display device comprising a super twisted nematic type liquid crystal display device having one or more birefringent films and an edge light type backlight, and a color liquid crystal having a tape carrier package as a liquid crystal driver. Display device. 27. The color liquid crystal display device according to claim 26, wherein the tape carrier package for a liquid crystal driver is arranged so as to wind up a fluorescent discharge tube of an edge light type backlight. 28. A so-called micro tape carrier package in which a string-shaped LSI chip for a liquid crystal driver is used for a LST chip for a liquid crystal driver is used as a tape carrier package for a liquid crystal driver.
6. The color liquid crystal display device according to item 6. 29. A nematic liquid crystal having a positive dielectric anisotropy and to which an optical rotatory substance is added is sandwiched between electrode substrates provided with a color filter in either one of a pair of upper and lower surfaces which are opposed to each other. A liquid crystal element having a twisted spiral structure in the range of 180 to 270 degrees in the thickness direction, a pair of polarizing plates provided with the liquid crystal element sandwiched therebetween, and at least one of the polarizing plate and the liquid crystal element. Super twisted nematic liquid crystal display element with one or more birefringent films and cold cathode fluorescent discharge tube or hot cathode fluorescent discharge tube as a backlight, light guide plate, diffusion sheet, reflection sheet, lamp reflection sheet In a color liquid crystal display device composed of an edge light type backlight composed of a personal computer, a liquid crystal display element is fixed by a metal frame and a light guide plate, Color liquid crystal display apparatus characterized by directly mounted to the case and the like. 30. A nematic liquid crystal having a positive dielectric anisotropy and to which an optical rotatory substance is added is sandwiched between electrode substrates provided with a color filter in either one of a pair of upper and lower surfaces which are opposed to each other. A liquid crystal element having a twisted spiral structure in the range of 180 to 270 degrees in the thickness direction, a pair of polarizing plates provided with the liquid crystal element sandwiched therebetween, and at least one of the polarizing plate and the liquid crystal element. Super twisted nematic liquid crystal display element with one or more birefringent films and cold cathode fluorescent discharge tube or hot cathode fluorescent discharge tube as a backlight, light guide plate, diffusion sheet, reflection sheet, lamp reflection sheet It is a color liquid crystal display device consisting of an edge light type back light consisting of a liquid crystal display element fixed with a metal frame and a light guide plate. In the color liquid crystal display device mounted directly on the case of such data, a color liquid crystal display device comprising the lighting circuit of the backlight to the main body of the personal computer.