Sanyo Electric Co., Ltd.

Mitsui Chemicals, Inc.

Masahiro Higuchi

Takanari Kusafuka

Yoshiaki Maeno

Youichiro Goto

Michiaki Sato

Kenji Torazawa

Toru Nose

Yoichi Tsuchiya

Shuichi Ichiura

Takashi Arai

Masahiro Sugi

Masato Yamada

Katsutoshi Hibino

Hitoshi Terasaki

Yoshiharu Uchihara

Kenji Kiyota

Hiroshi Yamashita

Yasuko Teragaki

Mikio Ichihashi

Minoru Ono

Kenkiti Okamoto

Tadahiro Miyazaki

Yoshiaki Yamada

Sadao Sakamoto

An optical discincludes a substrate. The substrate is formed by mixing polymethyl methacrylate and a polylactic acid-based resin composition. The polylactic acid-based resin composition contains polylactic acid-based resin in which the content of lactide is reduced to 1,000 ppm or less, and a mold release agent of 0.16 to 0.32 phr. The weight ratio of the polylactic acid-based resin to the polymethyl methacrylate is 70:30 to 50:50.

Optical disc and material for substrate thereof

In a beam irradiation device of the present invention, laser beams emitted from a semiconductor laser impinge on an irradiation lens supported by a lens actuator. The laser beams that have passed through the irradiation lens change in outgoing angle in the direction of a y-z plane as the lens actuator is driven. A laser beam scan in the target region is thus performed. A part of the laser beams that have passed through the irradiation lens is reflected and separated by a beam splitter. The separated beams are converged on a PSD through a converging lens. A DSP control circuit monitors a scan position of the laser beams that have passed through the irradiation lens based on a signal from the PSD. When an irradiation position has deviated from a scan trajectory, the DSP control circuit controls an actuator driving circuit to draw the irradiation position back onto the scan trajectory. This beam irradiation device can realize a smooth and stable beam scan operation with a simple construction.

Beam irradiation device

A display device includes a light guide plate. A light incident on the light guide plate from a linear light source is reflected by a reflecting surface of each of prisms and emitted from a lower surface of the light guide plate. The emitted light is irradiated onto a liquid crystal panel, reflected by a reflecting layer provided within the liquid crystal panel and advances toward a front direction of a screen. Herein, the light guide plate has on its lower surface as an emission surface a number of minute protrusions each having a shape of triangle in vertical cross-section in a manner that the protrusions cover with no space therebetween a whole effective area of the lower surface, and thereby to obtain an antireflection effect.

Light guide plate and display device

An outer light collecting portion,which sticks out of a light emission surface,to the light emission direction at the same time when a light guide plate is formed by resin forming with a mold. An area of a surface for collecting outer light is larger than that of a conventional light guide plate so as to collect outer light effectively. Light from a light source which is incidence through a light incident surface,reflects from a light reflection surface,and two side surface,of a light guide plate,and is emitted as synthesized light having the even directivity from a light emission surface

Light guide plate, surface light source using the light guide plate, and liquid crystal display using the surface light source

The present invention provides a light guide plate and a surface light source using the light guide plate to improve the utilization efficiency of external light and light from an internal light source and to achieve thinner width of the light guide plate. In this invention, internal light emitted from an internal light source,is brought to the inside of the light guide plate,from an internal light collecting surface,in the light guide plate,, and external light such as natural light is brought to the inside of the light guide plate,from an external light collecting portion,. The light brought to the inside of the light guide plate reflects and is converged several times from a reflective plate,mounted to the outside of the light reflective surface,and three side end surfaces,and is emitted from the light emissive surface,of the light guide plate,to a diffusing plate,. The light incident to the diffusing plate,is diffused uniformly within the desired angle range by the diffusing plate,and a lens sheet,, and is emitted from the lens sheet,as synthesized light.

Light guide plate, surface light source and display using the same

In a method of producing a lightguide plate for surface light source according to the present invention, a plate-shaped metal mold for defining the shape of a part of a cavity of a molding die and particularly, the shape of a light emitting surface of the lightguide plate for surface light source (a concavo-convex shape, a lenticular lens shape, etc.) is provided so as to be replaceable, to form a cavity having a desired shape by the replacement of the plate-shaped metal mold. Resin liquid is injected into the cavity, its resin liquid is solidified, and the resin is then released from the cavity. Consequently, a lightguide plate for surface light source having a desired shape and particularly, having its light emitting surface in a desired shape is produced.

Method of producing lightguide plate for surface light source,

A light guide plate is provided including a first lens portion comprising a plurality of recessed or projected lenticular unit lenses formed of the same resin as that of the light guide plate on a light emission surface. The plurality of lenticular unit lenses in the first lens portion are triangular prism portions whose respective vertexes have an angle of 125.degree. to 165.degree. and are so arranged that their respective ridge lines are nearly parallel to each other. Such construction makes it possible to set the number of lenticular lens sheets used to one or to further eliminate the necessity of the lenticular lens sheets, so that the cost of parts and the fabrication cost of the light guide plate can be reduced. A second lens portion may be provided on a light reflective surface opposite to the light emission surface on which the first lens portion is disposed, the second lens portion including a plurality of recessed or projected lenticular unit lenses formed of the same resin as that of the light guide plate. Alternatively, a light guide plate is provided having a plurality of grooves with approximately equal groove widths formed on a surface opposite to a light emission surface, the grooves being arranged substantially parallel to each other and the spacing between the grooves narrowing as the distance from the light incident surface increases, with the spacing from the far end of one of the plurality of grooves proximate to the light incident surface to the near end of a groove adjacent thereto farther away from the light incident surface being 5 to 15 times the groove width.

Light guide plate and surface light source using the light guide plate

A disc is provided which includes a disc body of disc shape having a center hole. An information recording area is formed on one side surface of the disc body. The information recording area has information thereon read by reflection of laser light. The information recording area has an inner circumferential edge positioned adjacent to the center hole. The disc body has a radius ranging from 39 mm to 80 mm, the center hole has a radius ranging from 7.5 mm to 7.55 mm, and the inner circumferential edge of the information recording area being positioned to extend from a radius of 15 mm to 22 mm from the center of the disc body. A disc may be manufactured by variations of the following disc manufacturing method including the steps of: supporting a stamper on a first mold by a supporting means; defining a forming space by clamping the first mold to a second mold; defining a center hole of the disc by advancing a center hole defining member into a center part of the forming space; connecting a injection means into the forming space by opening a gate member of a resin injection member and filling the forming space with a resin through a communicating hole from the injection means; and cooling the resin in the forming space after shutting off connection between the injection means and the forming space by closing the gate member of the resin injection member.

Optical disc manufacturing apparatus

The method of manufacturing an optical disc related to the invention first forms warp prevention layer on one surface or the other surface of the disc substrate where information is recorded on one surface, and then, recording film covering the surface opposite from the surface having warp prevention layer or beam reflection film covering the information-recorded surface, and finally protection layer covering either the beam reflection film or the recording film, in this order. Thus the optical disc related to this invention can prevent damage and dust from incurring and adhering to the other surface of the disc substrate when forming these films on one surface so that the warp prevention layer can be perfectly level by suppressing swell of the layer itself. Since the warp prevention layer is formed on one surface before forming those films mentioned above on the other surface, the one surface maintains satisfactory wetness, and as a result, foam is rarely generated between the warp prevention layer and the disc substrate. Furthermore, the method of manufacturing an optical disc related to the invention introduces a system which measures the warp of the disc substrate coated with warp prevention layer before coating protection film, and then properly adjusts the thickness of the protection film to a specific thickness enough to fully cancel the warp. This effectively minimizes warping of the disc substrate itself.

Growing community of inventors

Gifu, Japan

Masahiro Higuchi