Hitachi, Ltd.

Ryuji Kurihara

Koji Hirata

Nobuo Masuoka

Yoshie Kodera

Akihiko Kanouda

Takeshi Mochizuki

Masami Joraku

Yoshihiko Sugawara

Kobuo Masuoka

Fusao Sakuramori

In a circuit board disposed in parallel to a fixing plane, a guard spacer (abutting member) is disposed on a multi-layer printed circuit board on the side of the fixing plane to suppress deformation of the multi-layer printed circuit board to prevent short circuit if an impact is applied to the circuit board. The guard spacer may be a dummy electronic component or a plate member. An image display using the circuit board is also disclosed.

Circuit board and image display apparatus

A projector light source which facilitates molding of a reflector for obtaining a complicated reflecting surface and provides an improved cooling efficiency, which is characterized by molding the reflector of the light source using heat resistant plastic mixed with a high heat conductive material, whereby a molding accuracy is drastically improved compared to a heat resistant glass reflector, and a highly efficient light source is implemented by increasing a degree of design freedom using a high-order non-spherical reflecting surface. Furthermore, heat conductivity is increased by the use of a high heat conductive material for the reflector and heat dissipation to an outside is facilitated.

Projector light source and projection type image display device using the same

Provided is a projector light source which can effectively project a light beam having a sufficient volume from a lamp as a light source, and which is highly accurate and is excellent in workability. The projector light source comprising an arc tube for emitting a light beam; and a concave reflector including a hold part for holding the arc tube, and having a concave reflection surface for reflecting the light beam from the arc tube so that the light beam outgoes through an opening of the reflector, the concave reflector comprising a first reflector located in the vicinity of the hold part for holding the light emitting tube, and second reflector located in a part other than the hold part, and made of a material different from that of the first reflector. Further, the first reflector is made of heat-resistant glass, and the second reflector is made a material containing a heat-resistant organic material having a thermal deformation temperature which is lower than that of the heat-resistant glass.

Light source for projector and projection type image display apparatus using thereof

In a lamp operation controller and a method thereof, for obtaining a stable light emission, simply and certainly, without necessity of detection of a parameter accompanying discharge, the lamp operation controller, for operating a discharge lamp having a pair of electrodes, which are disposed at both ends of a light emission tube to have a predetermined distance therebetween, converts electric power of an electric power sourcethrough an inverter, into alternating voltage and alternating current, changing the polarity thereof continuously and alternately, so as to produce operating current, and apply that across the pair of the electrodes of the discharge lamp, thereby letting the lamp to emit a light. A driver circuit provides a pulse at a trailing edge of the lamp current or the lamp voltage to be supplied when the discharge lamp emits the light, and also determine amplitude of the pulse, in accordance with fluctuation on the lamp voltage (VL) with respect to lighting time of the discharge lamp, which is measured in advance.

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Yokohama, Japan

Ryuji Kurihara