West Electric Co., Ltd.

Panasonic Corporation

Kazuo Tanaka

Shinji Hirata

Hiroaki Yamamoto

Hiroyuki Sasai

Kuniaki Utsumi

Mariko Nakaso

Kouichi Masuda

Tsutomu Niiho

Toshitsugu Kashihara

Hisashi Ogura

A wireless communication system capable of keeping a level of a wireless signal received by a relay apparatus within a predetermined dynamic range. In a control apparatus, a transmitting section converts a downstream electric signal into a downstream optical signal and transmits the downstream optical signal to the relay apparatus via an optical transmission path. The relay apparatus converts the received downstream optical signal into a downstream electric signal and transmits the downstream electric signal as a wireless signal to a wireless communication terminal from a transmitting/receiving antenna section. In the relay apparatus, a level adjustment section adjusts the level of the wireless signal transmitted by the relay apparatus such that the receiving level of the wireless signal received by the relay apparatus is kept within a predetermined range.

Wireless communication system

An electronic flash unit being effective in emitting light repeatedly at high speed by boosting an applying voltage between main electrodes of a flash discharge tube twice or more as much as a charged voltage in a main capacitor connected parallel to a high voltage DC power source, wherein the electronic flash device has a plurality of boosting capacitors connected with the flash discharge tube through plural second control switches respectively and a common circuit including an insulated gate bipolar transistor IGBT, the main capacitor and a first control switch for selective excitations, and also connected with a primary winding of a trigger transformer via a trigger capacitor, a diode and so on for charges during being un-excited, and wherein the electronic flash device has a switch control device for selectively turning on one of the plural second switches and for simultaneously turning on the first switch so as to supply a high voltage to the flash discharge tube being combined with the charged voltages of the boosting capacitors and the main capacitor after second et seq light emission operations.

Electronic flash unit

The strobe apparatus of the present invention applies upon both the ends of the flash discharging tube the oscillating voltages to be caused in the primary winding of the trigger transformer by the discharging operation of the trigger capacitor, and also, quickly charges the trigger capacitor through the flash discharging tube at the ionized condition time. At the light emitting operation time, the high voltage of charging electric voltage or more of the main capacitor is applied upon both the ends of the flash discharging tube without fail so that the light emission coming off prevention at the high speed repeating light emitting operation can be realized.

Strobe apparatus

A strobo device in accordance with the present invention is provided with an insulated gate bipolar transistor connected to a flash discharge tube in series and a step-up capacitor to step up a voltage between the main electrodes of the flash discharge tube in the luminous operation. The step-up capacitor is connected so that a terminal on the side connected to a cathode of the flash discharge tube can have a high potential and the step-up capacitor is also connected so as to be charged by a current flowing through the flash discharge tube, which is not flashing. Thus the device realizes a rapid charging of the step-up capacitor. In this way a high voltage, at least more than twice as high as the charged voltage of the main capacitor, can be applied between the main electrodes of the flash discharge tube in the luminous operation, resulting in preventing flash failures during the repeating high-speed luminous emissions.

Strobo device

In an electronic flash unit, a voltage applying device is provided to apply a predetermined voltage to the gate of an insulated gate bipolar transistor (IGBT), connected in series with a flash tube, for controlling the light-emission operation of the flash tube. The voltage applying device produces the predetermined voltage in response to the start of the operation of a DC high voltage power source. Thus, the voltage applying device applies a driving voltage to the gate of the IGBT without responding to a light-emission command signal. The IGBT enters a conduction standby state in response to the start of the operation of the DC high voltage power source, and is placed in a fully `on` state when a trigger circuit is operated by the light-emission command signal. The driving voltage can be applied to the gate in a very simple arrangement which does not require to respond to the trigger signal.

Strobo apparatus

A photographic flash device comprising a main capacitor for flashing a flash discharge tube, a DC-DC converter, a constant-voltage circuit for controlling the oscillation function of the DC-DC converter and an indication means capable of discriminatively indicating states of the voltage of the main capacitor in three different voltage ranges, first range being from zero to a first predetermined voltage above which flashing is possible, second range being from a first predetermined voltage to a second predetermined voltage, the third range being from the second predetermined voltage to a third predetermined maximum voltage, respectively.

Photographic flash device

An electronic flash device comprising a DC-DC converter circuit which converts a low voltage DC source to a high voltage DC current for charging a main discharge capacitor, a flash discharge tube which is adapted to flash by means of the energy stored in the main discharge capacitor, and a display circuit. The DC-DC converter circuit includes an oscillation transformer having a primary winding, a secondary winding magnetically connected with the primary winding, an auxiliary winding and further a second auxiliary winding, an oscillation transistor, and an auxiliary capacitor connected with the auxiliary winding for causing the oscillation transistor to be started; and the display circuit is lit for display when the voltage generated across the second auxiliary winding and the voltage applied across the auxiliary capacitor are superposed to reach a predetermined value.

Electronic flash device with voltage display

In a photographic flash device comprising a flash discharge tube, for example a xenon discharge tube, a main capacitor which is connected across electrodes of said flash discharge tube and is for storing electric charge to be discharged in said flash tube, a triggering capacitor which is connected in series with a primary coil of a triggering transformer and a synchronous switch, and a voltage indicating glow discharge lamp for indicating completion of charging in the main capacitor. A safety circuit for prohibiting accidental flashing is constituted by comprising a switching means which suspends function of said triggering capacitor.

Growing community of inventors

Neyagawa, Japan

Kazuo Tanaka