Hitachi Media Electronics Co., Ltd.

Hitachi, Ltd.

Tetsunosuke Nakamura

Kouji Kitou

Fumio Haruna

Masaru Shimizu

Hiroshi Kimura

Akihiko Kanouda

Masami Joraku

Kazuhiro Takizawa

Disclosed herein is a discharge lamp lighting device which realizes the minute control of the lighting sequence and electric power of a high-pressure discharge lamp and the control of various anti-error protecting functions by mounting a microcomputer. However, since microcomputer processing typically progresses in accordance with the programs previously recorded on a ROM, various actions of the discharge lamp are controlled in accordance with ROM-recorded data settings. To modify these settings, the contents of the ROM need to be updated. Therefore, a function for communicating with an external device is assigned to the microcomputer so that various data settings can be modified.

Discharge lamp lighting device

A computing circuit computes a target value of a current to be supplied to a discharge lamp and generates a pulse control signal for superpose a pulse current. Furthermore, the computing circuit controls a current control circuit so that a pulse current is superposed on a lamp current at a predetermined cycle and power supplied to the discharge lamp is kept constant. For that purpose, the computing circuit lowers a DC current level of the lamp current when a pulse current is superposed on the lamp current, and exercises control so that an integrated amount of power at a predetermined cycle is equalized to a predetermined integrated amount of power.

Discharge lamp lighting device and projection type image display apparatus having the same

A discharge lamp lighting apparatus has a problem that a microcomputer within the apparatus falls down into malfunction due to noises generated in an inside thereof. With such the structure of the discharge lamp lighting apparatus that an operation of a calculation processing circuit, which is built up with the microcomputer, etc., is stopped through stopping the supply of electric power to the calculation processing circuit or bringing it into a sleep mode, it is possible to protecting it from the malfunction, during a time period when high voltage is generated just after starting of lighting of the discharge lamp. Also, with applying a protection processing by means of the calculation processing circuit and also applying an analog protection circuit, in common with, thereby it is possible to ensure reliability thereof further.

Discharge lamp lighting apparatus

Disclosed herein is a discharge lamp lighting device which realizes the minute control of the lighting sequence and electric power of a high-pressure discharge lamp and the control of various anti-error protecting functions by mounting a microcomputer. However, since microcomputer processing-typically progresses in accordance with the programs previously recorded on a ROM, various actions of the discharge lamp are controlled in accordance with ROM-recorded data settings. To modify these settings, the contents of the ROM need to be updated. Therefore, a function for communicating with an external device is assigned to the microcomputer so that various data settings can be modified.

A compact, thin-type, noise-tolerant and highly reliable electric power unit includes an input portion through which a predetermined voltage is applied, a plurality of power circuits for generating a plurality of different voltages from the predetermined voltage applied to said input portion, an output portion for outputting the plurality of different voltages generated in the plurality of power circuits, a control unit having a function to stabilize the plurality of different output voltages, and an insulated substrate which supports the input portion, the plurality of power circuits, the output portion and the control unit, and further has a printed wiring pattern for electrically coupling the constituent components of the electric power unit. By disposing each group of components which compose each of plurality of power circuits into a predetermined area corresponding to each output voltage, or by arranging the components such that the height of each of the plurality of constituent components for the power circuits is adapted to become approximately the same as or less than the height of the transformer, a compact and thin-type elective power unit which is noise-tolerant and highly reliable is achieved.

Growing community of inventors

Yokohama, Japan

Tetsunosuke Nakamura