Kuraray Co., Ltd.

Tohoku University

Sharp Corporation

Ikuo Onishi

Katsuya Fujisawa

Shigeki Kikuyama

Satoko Horikoshi

Toshiyuki Ito

Rikuji Watanabe

Tadahiro Ohmi

Yuichiro Yamada

Tokihiko Shinomiya

Toshiaki Sato

Yasuyuki Shirai

Toshiyuki Yoshikawa

Ichiro Matsuzaki

Mitsuo Matsumoto

Takashi Ishizumi

Yoshihiro Kumagai

Tokuo Ikari

Shinji Hiramatsu

Yoshiki Mukoo

Kiwamu Takehisa

Etsuo Nakazato

Yuhsaku Ajichi

Tsuyoshi Kanda

Yoichi Hashimoto

Isao Hamashima

A large liquid crystal display () comprises a light guide plate () arranged on the back side of a liquid crystal panel (). The front surface of the light guide plate () is flat, while the back surface thereof is concave. The upper and lower end faces of the light guide plate () respectively facing hot cathode fluorescent lamps () have a convex shape projecting toward the respective lamps. White light from the fluorescent lamps is incident on the upper and lower end faces of the light guide plate directly or by being reflected by reflectors (), and propagates within the light guide plate while being reflected by the front and back surfaces of the light guide plate. At the front surface of the light guide plate, a part of the white light is directed toward the back side of the liquid crystal panel () by a light guide portion ().

Liquid crystal display and light guide plate

In a lighting device, suppose a distance between centers of linear light sources is D and a distance between the linear light sources and a light control member is H and a function representing an outgoing light intensity toward a normal direction at a position coordinate X (light source position shall be X=0) and f(X&#x2212;D)+f(X)+f(X+D), in a range of &#x2212;D/2&#x2266;X&#x2266;D/2, a ratio between g(X)and g(X)is 0.6 or more, a minimum value Xis in a range of &#x2212;3.0D&#x2266;X&#x2266;&#x2212;0.5D, a maximum value Xis in a range of 0.5&#x2266;X&#x2266;3.0D, and a cross-sectional shape of a given convex portion in X direction is formed of areas with (2N+1) number of different gradients represented by a certain relationship obtained from D, H and X.

Lighting device and light control member used therefor and image display device using the lighting device and the light control member

The invention is directed to a lighting system having a reflector, light sources and a light control member sequentially disposed from a light incident side to a light outgoing side. Preferably used for large displays requiring high uniformity, this invention eliminates lamp image and removes the necessity to do light source repositioning, while enabling luminance in the exit plane to achieve excellent luminosity and uniformity. This invention achieves total light transmittance of more that 50% when light is incident at a predetermined angle &#x3b1; from the normal direction of the incident plane and achieves 1.05-3 times more total light transmittance than when the light is from a direction normal to the incident plane. This is achieved by the light control member by controlling the ration between total light transmittance in the positions of greater transmittance and the total transmittance in the positions of lesser transmittance.

Lighting system, image display apparatus using the same and light diffusion plate used therefor

The invention is directed to a lighting system having a reflector, light sources and a light control member sequentially disposed from a light incident side to a light outgoing side. Preferably used for large displays requiring high uniformity, this invention eliminates lamp image and removes the necessity to do light source repositioning, while enabling luminance in the exit plane to achieve excellent luminosity and uniformity. This invention achieves total light transmittance of more than 50% when light is incident at a predetermined angle a from the normal direction of the incident plane and achieves 1.05&#x2013;3 times more total light transmittance than when the light is from a direction normal to the incident plane. This is achieved by the light control member by controlling the ratio between total light transmittance in the positions of greater transmittance and the total transmittance in the positions of lesser transmittance.

Lighting system image display apparatus using the same and light diffusion plate used therefor

A planar light source device includes a light source , a reflector shade , a light guide member having at least one side face positioned adjacent the light source for receiving light from the light source and reflected by the reflector shade, and a light output plate positioned adjacent the light guide member with a first surface positioned adjacent a light exit surface of the light guide member . The first surface is formed with a multiplicity of projections having respective tips held in tight contact with the light exit surface of the light guide member , at least a portion of each of the projections having a curved facet. Of a function descriptive of a sectional shape of each of the projections that is parallel to a direction of travel of light and also a direction normal to the light output plate , the maximum value of the absolute value of a linear differential of a portion representative of a facet counter to the light source is chosen to be within the range of to

Planar light source and display device using the same

Provided is an optical device through which the angle of light passing and going out has little wavelength dependency and which is well applicable to Fresnel lenses with little coloration of light passing through it. The optical device has a diffraction grating formed on one surface and capable of diffracting rays of light incident thereon, and has a refracting member (e.g., a Fresnel lens) formed on the other surface opposite to the diffraction grating and capable of refracting the diffracted rays of light from the diffraction grating to make the refracted rays of light go out of it, in which the wavelength dependency of the diffractive angle of the main rays diffracted by the diffraction grating compensates for the wavelength dependency of the refractive angle thereof refracted by the refracting member, or that is, the former wavelength dependency is opposite to and cancels out the latter one.

Optical device and Fresnel lens sheet

Provided is a panel light source device through which the light availability is increased. The luminance of light to be outputted by the device in the oblique direction that oversteps the front direction of the device is reduced. The device comprises a light source 2, a reflector 8, a waveguide 3 that receives through its side surfaces the light having been outputted by the light source 2 and reflected by the reflector 8, an output light modulator 6 as provided on the light output surface of the waveguide 3 to modulate the output light from the light output surface of the waveguide 3 toward the front direction of the light output surface, and an input light modulator 9 as provide between the light source 2 and the side surface of the waveguide 3 to modulate the output light from the light source 2 toward the light output surface of the waveguide 3 or toward the back surface of the waveguide 3 opposite to the light output surface thereof.

Panel light source device and display comprising it

An image display apparatus includes an image display device such as, for example, a liquid crystal display panel, having a plurality of dot-shaped picture elements arranged in a two-dimensional pattern, and a diffraction grating disposed on an optical path through which imagewise rays of light emerging from the device travel. To minimize a reduction in quality and contrast of an image displayed by the device, the member has a spatial cut-off frequency chosen to be of a value lying between the sampling frequency, determined by the pitch between picture elements of the image display device, and the Nyquist frequency. For the same purpose, the intensity of .+-.1st order light relative to the intensity of 0-th order light in the diffraction grating is within the range of 60 to 80% at a center wavelength of the image display device, and the sum of the intensity of the 0-th order light and that of the .+-.1st order light relative to that of total diffracted light is equal to or higher than 80% at the center wavelength of the device.

Image display apparatus

Growing community of inventors

Tsukuba, Japan

Ikuo Onishi