Seiko Instruments Inc

Naofumi Yamauchi

Makoto Kurihara

Takayasu Sado

Hiroyuki Fujita

Katsunori Honma

Takayoshi Hanami

Mitsuyoshi Hara

Adjustments during assembly of an illuminating unit having a conventional light pipe in order to position the light pipe and a light guide plate are laborious. Further, a minute prism group having a pitch on the order of 100 &#x3bc;m must be provided to a side surface of the light pipe in order to uniformly guide illuminating light to the light guide plate. An illuminating unit of the present invention is provided with a light guide plate having an illuminating surface that is illuminated by light from a point light source, and a light pipe having an incident surface to which light from the point light source is made incident and an emerging portion from which the light emerges to the light guide plate. The emerging portion and the light guide plate are integrally joined.

Illuminating unit and display device using the unit

To realize at low cost a liquid crystal display device which is thin and in which display on a single liquid crystal panel can be viewed in both ways, from the front and from the back. The liquid crystal display device includes a liquid crystal panel in which a liquid crystal layer is interposed between opposing substrates, and a polarizer and a reflection-polarizing plate provided so as to interpose the liquid crystal panel therebetween. The reflection axis of the reflection-polarizing plate is set in the same direction as a polarization direction of light that exits the liquid crystal panel after its polarization direction is changed in the liquid crystal layer, or a polarization direction of light that exits the liquid crystal panel without being changed in polarization direction in the liquid crystal layer. Due to this arrangement, a liquid crystal display device can be provided which is thin and capable of displaying on both the front side and the back side.

Liquid crystal display device viewable from both sides using incident light from only one of the sides, and using only one reflection-polarizing plate on one of the sides

A liquid crystal display apparatus arranged with a light guide plate of an illuminating apparatus between two liquid crystal panels for increasing an efficiency of utilizing light of the illuminating apparatus to thereby increase brightness both in a transmission display mode and a reflection display mode. For that object, there is constructed a constitution of providing a first lower polarizer between a first liquid crystal panel and a light guide plate, a second lower polarizer between a second liquid crystal panel and the light guide plate and a reflection-polarizing plate between the light guide plate and the second lower polarizer. Thereby, the efficiency of utilizing light of the illuminating apparatus can be increased. Further, a transmission axis of the first lower polarizer and a reflection axis of the reflection-polarizing plate are aligned in the same direction and a transmission axis of the second lower polarizer is set to make an angle &#x3b8; (incidentally, &#x3b8; is an angle other than 90 degrees) relative to the reflection axis of the reflection-polarizing plate. A rate of reflection/transmission of the second liquid crystal panel can freely be set by changing the angle.

Liquid crystal display apparatus

A liquid crystal device comprises a liquid crystal cell having a liquid crystal material sandwiched between a pair of substrates, the liquid crystal material having a retardation less than 1 .mu.m, a polymer film comprised of an optically anisotropic substance disposed on one of the substrates opposite the liquid crystal material, a color polarizing plate disposed on the polymer film opposite the one substrate, and a polarizing plate disposed on the other of the substrates opposite the liquid crystal material. The liquid crystal material preferably comprises a super twisted nematic liquid crystal material, and the color polarizing plate preferably comprises a red, green or blue polarizing plate.

Growing community of inventors

Chiba, Japan

Naofumi Yamauchi