Casio Computer Co., Ltd.

Zenta Kikuchi

Tetsushi Yoshida

Takashi Miyashita

Jiro Takei

Hisashi Aoki

Yoshinaga Miyazawa

Satoru Shimoda

Katsuhito Sakamoto

Soichi Sato

Minoru Kanbara

A liquid crystal display device, for displaying pure white, has a first substrate having first electrodes formed thereon; a second substrate positioned to face the first substrate and having second electrodes formed thereon; a liquid crystal sealed between the first and second substrates; and first and second polarization plates arranged to sandwich the first and second substrates and having such polarization characteristics that when the first and second polarization plates are placed one on the other in such a way as to have substantially perpendicular transmission axes, a value acquired by dividing a transmittance of light with a wavelength of 500 nm by a transmittance of light with a wavelength of 440 nm becomes substantially smaller than 0.4. The first and second polarization plates have optical characteristics such that when the first and second polarization plates are placed one on the other in such a way as to have substantially parallel transmission axes, a value acquired by subtracting a transmittance of light with a wavelength of 640 nm from a transmittance of light with a wavelength of 460 nm is greater than -3%.

LCD device with polarizers having polarizing and transmittance

A color liquid crystal display apparatus comprises an ECB (Electrically Controlled Birifringence) type liquid crystal display device, which has a plurality of dots arranged in a matrix form and displays a plurality of colors in accordance with applied voltages dot by dot, and a driving circuit. The driving circuit includes an image memory, a display controller, a conversion table, a D/A converter and drivers. The display controller reads image data stored in the image memory. This image data defines a display color of a pixel consisting of a plurality of dots and a gradation. The conversion table converts image data to voltage data defining voltages to be applied to a plurality of dots of the liquid crystal display device in order to display the color and gradation defined by the image data. The D/A converter converts this voltage data to an analog voltage and the drivers apply this analog voltage to each dot of the liquid crystal display device. The color and gradation defined by the image data are expressed by the visual combination of the display colors of a plurality of dots constituting each pixel. The thicknesses of the liquid crystal layer at a plurality of dots constituting each pixel in the ECB liquid crystal display device differ from one another.

Birifringence control type liquid crystal display device and apparatus

A birefringence control type color liquid crystal display device includes a liquid crystal cell having first and second substrates; first and second electrodes formed on opposing surfaces of the first and second substrates; a first aligning film formed on the first electrode and subjected to an aligning treatment in a first direction; a second aligning film formed on the second electrode and the second substrate and subjected to an aligning treatment in a second direction intersecting the first direction at 90 degrees; and a liquid crystal sealed between the first and second aligning films and twisted at 90 degrees. The device further includes a first polarization plate arranged outside of the second substrate and having a transmission axis intersecting the first direction at substantially 140 to 160 degrees; a second polarization plate arranged outside of the first substrate and having a transmission axis intersecting the transmission axis of the first polarization plate at substantially 10 to 40 degrees; a first retardation plate arranged between the second substrate and the second polarization plate, with a direction of a maximum refraction index intersecting the first direction at 130 to 160 degrees; and a second retardation plate arranged between the second substrate and the second polarization plate, with a direction of a maximum refraction index intersecting the first direction at substantially 40 to 80 degrees.

Color liquid crystal display device and liquid crystal display apparatus

A color liquid crystal display device comprises a liquid crystal cell having liquid crystal molecules twisted by 90.degree., two polarization plates, a reflector and two retardation plates. The product .DELTA.n.d of the refractive anisotropy .DELTA.n and the LC layer thickness d of the liquid crystal cell, the retardations of the retardation plates, the directions of the transmission axes of the polarization plates and the phase delay axes of the retardation plates are set in such a way that the color of outgoing light changes to red, green, blue, black or white in accordance with an applied voltage. The transmission axis of one of the polarization plates is set in a direction of 110.degree. to 130.degree. in an opposite direction to the twist angle of the liquid crystal molecules and the transmission axis of the other of the polarization plates is set in a direction of 127.degree. to 140.degree. in an opposite direction to this twist angle.

Color liquid crystal display device with optical axes of retardation

A color liquid crystal display device including a transparent first substrate having an inner surface and at least one transparent electrode formed thereon, and an insulating second substrate having an inner surface arranged to oppose the inner surface of the first substrate and at least one electrode formed on the inner surface of the second substrate. A liquid crystal layer is sandwiched between the inner surfaces of the first and second substrates and has a predetermined initial aligned state. A polarizing member is arranged on a first substrate side of the liquid crystal layer, and at least one retardation plate is provided for coloring light which emerges from the liquid crystal display. The retardation plate is arranged between the liquid crystal layer and the polarizing member such that an optical axis of the retardation plate with respect to a transmission axis of the polarizing member is not parallel to or perpendicular to the transmission axis. A reflecting member is arranged on a liquid crystal layer side of the second substrate.

Color liquid crystal apparatus

A polymer dispersed liquid crystal display device includes first and second substrates arranged to oppose each other, a polymer dispersed liquid crystal layer arranged between the first and second substrates, first electrodes arranged on the inner surface of the first substrate, a reflecting member arranged on the inner surface of the second substrate and designed to reflect light transmitted through the polymer dispersed liquid crystal layer, a coloring film for coloring light transmitted through the polymer dispersed liquid crystal to display a color image, and second electrodes arranged between the inner surface of the second substrate and the liquid crystal layer. At least a portion of each second electrode opposes a corresponding first electrode. A light coloring film is arranged on the reflecting member, contains a fluorescent material, and converts light transmitted through the polymer dispersed liquid crystal layer into light having the same color as that of fluorescent light emitted from the fluorescent material.

Reflective liquid crystal display device

A liquid crystal device includes a TFT or active element substrate on which TFTs and pixel electrodes are arranged in the form of a matrix, a counter substrate having a counter electrode formed thereon and arranged to oppose the active element substrate, a polymer dispersed liquid crystal layer arranged between the active element substrate and the counter substrate and having a polymer resin and a liquid crystal which are dispersed, and a fluorescent film arranged on the pixel electrode. The device displays an image by controlling scattering, absorption, and transmission of light passing through the polymer dispersed liquid crystal layer. The phosphor film converts part of supplied light into fluorescent light having a predetermined wavelength and outputs colored light. Light used for a display is increased in intensity by the fluorescent light emitted from the phosphor film, thereby displaying a bright image.

Active matrix polymer dispersed liquid crystal display device with

A polymer dispersed liquid crystal display device includes an active element substrate on which active elements and pixel electrodes are arranged in the form of a matrix, a counter substrate having a counter electrode formed on a surface, of the counter substrate, opposing the active element substrate, and a polymer dispersed liquid crystal film arranged between the active element substrate and the counter substrate and formed by dispersing a polymer resin and a cholesteric liquid crystal. The cholesteric liquid crystal is in a randomly aligned state to be twisted at a specific helical pitch in the absence of an electric field. When an electric field is applied across the pixel electrodes and the counter electrode, the cholesteric liquid crystal is aligned along the electric field, and the polymer dispersed liquid crystal film is set in a light-transmitting state, thereby setting a display in a bright state. When the application of the electric field is stopped, the cholesteric liquid crystal is restored, within a short time, to a randomly twisted/aligned state by the restoring force of the cholesteric liquid crystal, and the polymer dispersed liquid crystal film is set in a light-scattering state, thereby setting a display in a dark state. When a dichroic dye is added to the cholesteric liquid crystal, the dark display becomes dark, thereby increasing the contrast of an image.

Polymer dispersed liquid crystal display device

A polarizer is arranged on the incident side of a TN type liquid crystal cell in which the arrangement of liquid crystal molecules is twist-aligned through substantially 90.degree. in a direction from one substrate to the opposite substrate and the value of a product .DELTA.n.sub.c.d.sub.c of a refractive index anisotropy .DELTA.n.sub.c and a gap d.sub.c is set within a range of 300 to 600 nm, and an analyzer is arranged on the exit side of the liquid crystal cell. A twist-aligned retardation plate, in which the arrangement of polymer molecules is twist-aligned through 90.degree. in a direction opposite to the twist direction of the twist orientation of the liquid crystal molecules and the value of .DELTA.n.d ranges between 100 and 600 nm, is arranged between the liquid crystal cell and the analyzer.

Liquid crystal display device

A polarizer and an analyzer are respectively arranged on the incident and exit sides of a twisted nematic liquid crystal cell, and at least one biaxial retardation plate is arranged between the polarizer and the analyzer. The biaxial retardation plate is arranged such that its phase delay axis is parallel or perpendicular to the aligning treatment direction of an aligning film on the incident side of the liquid crystal cell. The polarizer is arranged such that its light-transmitting axis is parallel or perpendicular to the incident-side aligning treatment direction. The light-transmitting axis of the analyzer is set to be perpendicular to the light-transmitting axis of the polarizer. A liquid crystal material sealed in the twisted nematic liquid crystal cell is twisted at about 90.degree.. The biaxial retardation plate has a refractive index n.sub.X in an extending direction of the retardation plate, a refractive index n.sub.Y in a direction perpendicular to the extending direction, and a refractive index n.sub.Z in a direction of thickness, which satisfy the relation n.sub.Y &lt;n.sub.Z &lt;n.sub.X. A product .DELTA.n.multidot.d of a refractive index anisotropy .DELTA.n and a thickness d of the biaxial retardation plate falls within the range of approximately 300 to 400 nm.

Liquid crystal display device with 2 adjacent biaxial retardation plates

An STN liquid crystal display device includes a polarizer and an analyzer which are arranged to sandwich an STN liquid crystal cell, and two biaxial retardation plates arranged between a substrate of the liquid crystal cell and the analyzer. The polarizer is arranged such that its light-transmitting axis is inclined at about 140.degree. with respect to an incident-side aligning treatment direction of the liquid crystal cell. The analyzer is arranged such that its light-transmitting axis is inclined at about 55.degree. with respect to the incident-side aligning treatment direction. The biaxial retardation plate on the liquid crystal cell side is arranged such that its phase delay axis is inclined at about 40.degree. with respect to the incident-side aligning treatment direction. The biaxial retardation plate on the analyzer side is arranged such that its phase delay axis is inclined at about 5.degree. with respect to the incident-side aligning treatment direction. Each biaxial retardation plate has a refractive index n.sub.X in the extending direction of the retardation plate, a refractive index n.sub.Y in the direction perpendicular to the extending direction, and a refractive index n.sub.Z in the direction of thickness, which satisfy n.sub.Y &lt;n.sub.Z .ltoreq.n.sub.Y +0.3.multidot..DELTA.n (for .DELTA.n=n.sub.X -n.sub.Y).

Liquid crystal display device with at least one biaxial retardation film

A liquid crystal display device includes first and second substrates bonded with each other with an annular seal sandwiched therebetween. A liquid crystal is filled in a sealed space between the substates, molecules of which are so aligned that they are twisted at 90.degree.. The value of a product .DELTA.nd of the refractive-index anisotropy .DELTA.n of a LC layer and the LC layer thickness d falls from 350 nm to 700 nm. A first electrode and a first aligning film executed by an aligning treatment in a predetermined first direction and covering the electrode are formed on an inner surface of the first substrate. Second electrodes and a second aligning film executed by an aligning treatment in a second direction different at 90.degree. from the first direction and covering the electrode are formed on an inner surface of the second substrate. A pair of polarizing plates are disposed outsides of the both substrates, so that a polarizing axis of one plate is directed toward a direction perpendicular to or parallel to the first direction and that of another plate is directed to cross at 90.degree. the former axis. A retardation plate is disposed between the polarizing plates, so that a direction of a delayed or advanced phase axis thereof is equal to or different in a range of .+-.15.degree. from the first direction. The product .DELTA.nd of the retardation plate falls from 300 nm to 600 nm.

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Hamura, Japan

Zenta Kikuchi