摘要:
In the constant-voltage automatic charging strobe circuit (100), the power circuit (20) for driving the automatic exposure mechanism rectifies the AC voltage generated in the collector of the oscillation control transistor (Q1) connected to the primary side of the step-up transformer (T1) to direct current by means of the rectifying diode (D4), smoothes the current by means of the capacitor (C3), and generates a DC secondary source. This DC secondary source is stepped up to a higher voltage than the battery voltage (VB), through the transistor (Q2) that is turned on and off by the phototransistor (PH1) for determining the level of ambient light, and is supplied as the source for driving the aperture control solenoid (RE1).
摘要:
A reflector used in an electronic flash device that collectively emits direct light emitted from a light source and reflected light that has been reflected by a reflective surface onto a subject, and an electronic flash device that uses such reflector. The reflector includes a pair of first reflective surfaces that are composed of portions of a cylindrical curved surface and face one another, and a second reflective surface that is contiguous with the pair of first reflective surfaces and inside which a xenon lamp is housed. Contiguous portions where the pair of first reflective surfaces and the second reflective surface are contiguous are set closer to the opening of the pair of first reflective surfaces than a center of the xenon lamp. With this construction, by it is possible to maintain a predetermined optical performance while making the electronic flash device smaller and slimmer.
摘要:
A reflector used in an electronic flash device that collectively emits direct light emitted from a light source and reflected light that has been reflected by a reflective surface onto a subject, and an electronic flash device that uses such reflector. The reflector for an electronic flash device includes a pair of first reflective surfaces 24, 25 that are composed of portions of a cylindrical curved surface and face one another and a second reflective surface 26 that is contiguous with the pair of first reflective surfaces 24, 25 and inside which a xenon lamp 12 is housed. Contiguous portions B1, B2 where the pair of first reflective surfaces 24, 25 and the second reflective surface 26 are contiguous are set closer to the opening 13a of the pair of first reflective surfaces 24, 25 than a center O of the xenon lamp 12 that is the light source. With this construction, by emitting all or the majority of the reflected light to the front from the opening, it is possible to maintain a predetermined optical performance while making the electronic flash device smaller and slimmer.
摘要:
This invention is designed to reduce the number of parts in the circuits of a constant-voltage automatic charging strobe circuit, thus reducing the cost. In addition, it allows a user to decide when to use the strobe flash. In a oscillation charge/discharge circuit, an oscillation startup switch is installed between a battery and a transistor through the primary coil of a step-up transformer. When the switch is closed, the direct current input to the transistor is suppressed, and an abnormal input current control resister may have a low resistance value. A trigger flash circuit comprises a circuit that both controls the constant-voltage flash of a neon lamp NE and controls the oscillation stop of the transistor. A recharge circuit comprises a circuit that uses the resistor in the primary coil of the step-up transformer and a capacitor that takes out pulse fluctuations when the xenon lamp Xe is flashed. This invention also has a switch mechanism which forms a charging route in the main capacitor under normal conditions, and which acts to start the flash of the flash element and prevent recharging when the camera shutter is operated. A main capacitor can be charged when the oscillation startup switch is operated only when the user wants to use the strobe.