Stanley Electric Co., Ltd

Keizo Sekido

Takayuki Yoneya

Toshiyuki Terada

Tatsuya Hioki

Kimihiro Iritono

Shigekazu Kato

To reduce the time until the start of the lighting while suppressing the overshoot of the current. A method to carry out lighting control of a semiconductor light emitting element using a lighting control device where the lighting control device includes a switching element serially connected to the semiconductor light emitting element and having a control terminal to control a conductive state, and a control circuit to control the control terminal. The method including: increasing a control voltage of the control terminal of the switching element from an initial value to a first value in a relatively short time by the control circuit; and increasing the control voltage of the control terminal of the switching element from the first value to a second value in a relatively long time by the control circuit.

Lighting control method and lighting control device for semiconductor light emitting element, light emitting device

A strobe apparatus includes: a light-emitting semiconductor module; a current sense resistor connected in series to the light-emitting semiconductor module and adapted to sense a drive current flowing through the light-emitting semiconductor module to generate a sense voltage; a step-up voltage converter connected to the light-emitting semiconductor module and the current resistor and adapted to supply the drive current to the light-emitting semiconductor module and the current resistor; and a voltage converter controlling unit connected to the step-up voltage converter and the current sense resistor, and adapted to control the step-up voltage converter in accordance with a difference between the sense voltage and an input voltage, so that the drive current has a first level current followed by a second level current larger than the first level current.

Strobe apparatus having light-emitting semiconductor module driven by two-stepped drive current

A lighting control circuit for a flash discharge tube can include an IGBT drive circuit and a timer circuit provided in parallel to each other to output a drive voltage to an IGBT device. An OR circuit can be provided for delivering an output to the IGBT device based on the outputs from both the IGBT driver circuit and the timer circuit. Therefore, the IGBT device can be subject to a voltage output obtained by performing the logical sum of the outputs from the IGBT drive circuit and the timer circuit. This can ensure a necessary and sufficient voltage to the gate of the IGBT device.

Lighting control circuit for flash discharge tube and method of use

Light source devices for photography using LED elements as a light source known in the prior art provide insufficient quantity of light, and the inability to avoid size increases in order to generate a sufficient quantity of light has been problematic. A photography light source deviceaccording to the present invention has a light source comprising a plurality of LED elementsgenerating white light or light of the three primaries and arranged in one or more rows parallel with the direction of the longer side of the photograph, a casehaving a lens on which linear fresnel cutshave been applied in a linear direction parallel to the arrangement direction is mounted on the LED element, and upon lighting of the LED element, drive is performed with a current of between 3 and 50 times the magnitude of the rated current thereof and a lighting duration of between 10 and 600 msec. Accordingly, the linear fresnel cutsincrease the efficiency of illumination by distributing light uniformly over the area of exposure, and in addition, a large current is applied in a pulse type pattern as the drive current, thus solving the problems by allowing sufficient brightness to be achieved with no associated increases in size.

Photography light source device

A conventional stroboscope circuit in use for a film camera has encountered with problems that charging of a main capacitor is incapable when other functions of the camera are operated and that a charging operation is delayed. To solve aforesaid problems, the present invention is to charge the capacitor C1 for a flashlight illumination by a use of a stroboscope charging circuit 1. During that, a usual charging operation is performed by feeding a higher current which flows through a transistor Q1, in a manner wherein a control signal CTL is switched to an H (a high) level status. When the other functions of the camera are operated on the contrary, the charging is performed by feeding a lower current which flows through a resistor R1, wherein the control signal CTL is switched to an L (a low) level status.

Charging circuit for stroboscope

In a current cut-off type automated stroboscope circuit which controls a flashlight intensity by cutting off the current flowing through a flash lamp, a high-speed semiconductor switching device inserted in series with respect to the stroboscopic tube has been encountered up to now with malfunction and breakdown problems induced by chattering. To solve aforesaid problems, the present invention is to provide a xenon tube 1 with an IGBT 2 connected in series with respect to the xenon tube 1. The gate electrode of the IGBT is connected to two pnp-type transistors Q1 and Q2 substantially inbetween, both transistors of which are connected in series with respect to each other. The IGBT is controlled by turning on and turning off of the transistors Q1 and Q2. Furthermore, a time constant circuit which is formed of a capacitor C1 and a resistor R1 is connected to the transistor Q1. A gate voltage is applied to the IGBT 2 only for a certain period of time (one shot) which is defined by a time constant of CR product.

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Tokyo, Japan

Keizo Sekido