Alps Electric Co., Ltd.

Ryohei Kakuta

Hideaki Nagakubo

Mitsuaki Yamazaki

Satoshi Matsubara

Yoshifumi Masumoto

Seiji Tokita

In a liquid crystal display device, a light quantity control portion b 4,is formed to a dot shape by print or the like on a diffusion plate,interposed between lens sheets,and a light transmission member,on the side thereof near to a backlight source,composed of a cold cathode fluorescent lamp or the like. Since the dots of the light quantity control portion,have a light transmitting property to a certain extent, they reflect a part of the light from the backlight source,and permit the remaining light to pass therethrough. With this arrangement, there can be provided the liquid crystal display device capable of brightly and uniformly irradiating the entire surface of the effective display area of a liquid crystal panel from the backside thereof without emission lines.

Liquid crystal display device with light quantity control portion

The screen of a liquid crystal panel is divided into two portions. In the divided screens (upper screen and lower screen), the corresponding common electrodes (each for one divided screen) are simultaneously driven. The driving signal (common signal C,) of the upper screen and the driving signal (common signal C,) of the lower screen change in one cycle of four frame periods. More specifically, in the above-mentioned cycle, the common signal C,changes in a pattern (1&rarr;1&rarr;1&rarr;&minus;1), and the common signal C,changes in a pattern (1&rarr;&minus;1&rarr;1&rarr;1) in synchronization with each other. Accordingly, upon comparison of the common signals C,and C,it appears that the signal having the same waveform is applied to the common electrodes while being out of phase with each other. Thus, a difference of the drive frequency between the upper screen and the lower screen is eliminated. It is thus possible to provide an inexpensive liquid crystal apparatus, which is connected to an existing dual-scan interface, without degrading the display quality.

Liquid crystal display apparatus

A liquid crystal display device contains a liquid crystal panel and a light transmission member disposed below the liquid crystal panel. A reflection sheet is disposed below the light transmission member and a light source is disposed adjacent to one end of the light transmission member. A reflector encases the light source. The periphery of the reflector has reflection walls and forms an opening continuous with the reflection walls. Light direction control walls are formed near the opening of the reflector to control the direction of the light from the light source. The light direction control walls cut off light directed in directions other than a predetermined set of directions. An inner surface of the light direction control walls is composed of reflection layers formed from a different material from the material that forms the reflection walls.

Growing community of inventors

Fukushima-ken, Japan

Ryohei Kakuta