Olympus Optical Company, Ltd.

Hiroshi Yamada

Toshiaki Ishimaru

Yoshiaki Kobayashi

Akira Watanabe

Yukio Nakajima

Akira Inoue

Toyoji Sasaki

Muneaki Yoshida

Satoshi Kawakami

A camera comprises a liquid-crystal display device and a liquid-crystal control section. The liquid-crystal display device has a liquid crystal whose transmittance is variable. The liquid-crystal control section, in the photograph enable mode, brings the liquid crystal of the liquid-crystal display device into the light-transmitting state and, in the photograph disable mode, brings the liquid crystal of the liquid-crystal display device into a half light-transmitting state or the no-light-transmitting state.

Camera with the function of changing the transmittance of liquid-crystal

A camera has a liquid-crystal display device including a liquid crystal whose transmittance is variable. A sensing section senses an abnormality in the camera. A liquid-crystal control section, in a release signal wait mode, brings the liquid crystal of the liquid-crystal display device into a light-transmitting state and, when the sensing section has sensed an abnormality in the camera, changes the transmittance of the liquid crystal of the liquid-crystal display device.

A camera includes a liquid-crystal display device with a liquid crystal whose transmittance is variable. A liquid-crystal control section, in a release signal waiting mode, brings the liquid crystal of the liquid-crystal display device into the light-transmitting state and, when a release signal is output to turn on an exposure mode, lowers the transmittance of the liquid crystal of the liquid-crystal display device temporarily.

Camera with the function of lowering the transmittance of the

In a power-saving stroboscopic device, a main capacitor is not completely discharged even in full light emission, so that a predetermined amount of charge can be left in a main capacitor, in order to save power in a stroboscopic circuit of the device. A light emission unit of the stroboscopic device can perform full light emission and flat emission based on a period of light emission time set by predetermined conditions. The stroboscopic device comprises a light emission control unit and a control unit for controlling a period of light emission time, so that a residual voltage in a main capacitor in the stroboscopic circuit is higher than a residual voltage after full light emission, in order to improve the charging efficiency after the full light emission.

Power-saving stroboscopic device

A power supply circuit includes a booster circuit for boosting an output voltage from a power supply battery to predetermined positive and negative voltages, respectively. A main capacitor is charged by the predetermined positive or negative voltage boosted by the power supply circuit. In a discharge tube, a discharge current flows on the basis of the charge built up on the main capacitor, so that flash light emission is performed. A MOS controlled thyristor (MCT) is inserted in the loop of the discharge current from the main capacitor. A control circuit ON/OFF-controls the MCT by selectively applying the predetermined positive or negative voltage from the power supply circuit to the gate terminal of the MCT.

Electric flash apparatus using MOS controlled thyristor

A stroboscopic instrument is constructed of a gate-controlled switching element forming a discharge loop that is connected in series with a discharge lamp and main capacitor for storing charge that causes the discharge lamp to flash. The stroboscopic instrument further comprises: a stroboscopic flashing control circuit for controlling the operation of stroboscopic flashing; a low-voltage power supply that has an output voltage lower than the driving voltages of the stroboscopic flashing control circuit and the gate-controlled switching element; a first constant voltage regulator for stepping up the voltage of the low-voltage power supply up to the driving voltage of the stroboscopic flashing control circuit; and a second constant voltage regulator for stepping up the voltage of the low-voltage power supply or the output voltage of the first constant voltage regulator up to the driving voltage of the gate-controlled switching element.

Stroboscopic instrument having a gate-controlled-switching element and a

An electronic flash apparatus having a main capacitor for storing charges, a discharge light emitting tube for emitting light in accordance with the charges stored in the main capacitor, a CPU for performing camera sequence control, and an IGBT coupled to each of the discharge light emitting tube and the CPU. The CPU includes a light emission control terminal for controlling a light emission timing of the discharge light emitting tube and the CPU is supplied with a CPU operation voltage. The IGBT includes a gate terminal connected to the light emission control terminal of the CPU, a collector terminal, and an emitter terminal, wherein, responsive to the light emission control terminal inputting to the gate terminal a control voltage substantially equivalent to the CPU operation voltage, a channel is formed between the collector terminal and the emitter terminal and the charges of the main capacitor are discharged through the discharge light emitting tube.

Electronic flash apparatus using gate controlled switching device

A series circuit of a pass condenser and a neon lamp operate as a voltage detecting device. A resistance voltage dividing circuit has a connecting point between voltage dividing resistances which are connected to the connecting point between the pass condenser and the neon lamp of the voltage detecting device. The series circuit and resistance voltage dividing circuits are provided between a power source boosting circuit and a main condenser so that, when the main condenser has been fully charged, the neon lamp will conduct, causing a charge completion signal to be outputted and thereby the charging operation will be stopped. When the charge voltage of the main condenser is a flash possible voltage, the neon lamp will conduct for only a short time and the charge completion signal will be output accordingly for only a short time in the form of a pulse. The voltage detecting device thus outputs three types of signals over a single output line to indicate one of three possible charging states.

Electronic flashing device having a specific type of main capacitor

In this strobo apparatus, in a strobo controlling circuit in which such self-arc extinction-type gate-controlling type switching device as an IGBT is connected in series with a flash discharge tube to control the flash of the discharge tube, a bias voltage controlling the on/off operation of the above-mentioned gate-controlling type switching device is obtained from a biasing condenser charged with an exciting current of the flashing discharge tube or directly from a power source voltage boosting circuit through a resistance or sub-condenser.

Growing community of inventors

Hachioji, Japan

Hiroshi Yamada