Casio Computer Co., Ltd.

Katsuhito Sakamoto

Tomio Tanaka

Jun Ogura

Tetsushi Yoshida

Satoru Shimoda

Zenta Kikuchi

Hisashi Aoki

Soichi Sato

In a liquid crystal display having a wide viewing angle range, first and second retardation films each having negative optical anisotropy in which the refractive index in the axial direction tilted in a predetermined direction with respect to the normal line to the film plane are inserted between a liquid crystal cell including a pair of substrates and a front polarizer and between the liquid crystal cell and a rear polarizer, respectively, such that the direction components along the film planes of the axial directions are set along the aligning treatment directions of the liquid crystal cell. A third retardation film having refractive index anisotropy in the film plane is arranged between the first retardation film and the adjacent front polarizer such that the maximum refractive index direction in the film plane becomes parallel or perpendicular to the absorption axis of the front polarizer. The retardation difference generated by light that becomes incident on the liquid crystal display obliquely with respect to the normal direction is compensated by the third retardation film. Residual retardation in liquid crystal molecules near the substrate of the liquid crystal layer is compensated by the first and second retardation films. Hence, high-contrast display at a wide viewing angle can be obtained independently of the incident angle.

Liquid crystal display having wide viewing angle range

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

In a TFT liquid crystal display device using a DHF liquid crystal, the DHF liquid crystal is alienable to a first alignment state in which liquid crystal molecules are substantially aligned to a first direction, to a second alignment state in which the liquid crystal molecules are substantially aligned to a second direction and to an arbitrary intermediate alignment state between the first and second alignment states, in accordance with a voltage applied between the pixel electrodes and the opposing electrode. One of a pair of polarization plates has an optical axis set in substantially an intermediate direction between the first and second directions. The optical axis of the other polarization plate is set perpendicular to the optical axis of the former polarization plate. A pulse having a voltage whose absolute value corresponds to a display gradation and whose polarity changes frame by frame is applied to the DHF liquid crystal for each pixel in the selection period of that pixel. A single pulse is applied for a single image signal.

Liquid crystal display apparatus using liquid crystal having

In a TFT liquid crystal display device using a DHF liquid crystal, the DHF liquid crystal is alignable to a first alignment state in which liquid crystal molecules are substantially aligned to a first direction, to a second alignment state in which the liquid crystal molecules are substantially aligned to a second direction and to an arbitrary intermediate alignment state between the first and second alignment states, in accordance with a voltage applied between the pixel electrodes and the opposing electrode. One of a pair of polarization plates has an optical axis set in substantially an intermediate direction between the first and second directions. The optical axis of the other polarization plate is set perpendicular to the optical axis of the former polarization plate. A plurality of pulses having voltages corresponding to a display gradation and whose polarities change frame by frame are applied to the DHF liquid crystal for each pixel in the selection period of that pixel. A single pulse is applied to a pixel in a single frame.

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

An anti-ferroelectric liquid crystal device includes a first substrate on which pixel electrodes and an alignment film are formed, and a second substrate on which an opposite electrode and another alignment film are formed. These substrates are arranged to face each other. An anti-ferroelectric liquid crystal is sealed in a space defined between the substrates. The pixel electrodes arranged on the first substrate are connected to thin-film transistors formed on the first substrate. The thin-film transistors are selected by being supplied with control signals at their gates and data signals are supplied to their drains to apply data potentials to the pixel electrodes.

Anti-ferroelectric liquid crystal display device with intersecting

A liquid crystal display element includes one substrate on which pixel electrodes and TFTs connected to the pixel electrodes are arranged in a matrix form, the other substrate on which a counter electrode opposing the pixel electrodes is formed, and a ferroelectric liquid crystal sealed between the substrates and having a helical pitch smaller than a distance between the substrates. A row driver is connected to the TFTs to sequentially turn on the active elements. A column driver applies an initializing voltage consisting of first and second reset pulses for sequentially setting the ferroelectric liquid crystal in the first and second aligned states and a write voltage changing in accordance with the display gradation levels to the pixel electrodes through the ON active elements, thereby performing gradation display.

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Sagamihara, Japan

Katsuhito Sakamoto