# US 4,078,240 A · Photographic flash device

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 4,078,240 A
- Document ID: US4078240A
- Status: Granted
- Kind: A
- Application number: 05/710,927
- Filed: 1976-08-02
- Granted: 1978-03-07
- Earliest claimed: 1975-08-19
- Assignees: West Electric Company, Ltd.
- Inventors: Yoshikazu Kaneko; Hisashi Ogura
- Web page: https://patentgrep.com/patent/US4078240A

## CPC

- G03B 15/05: Combinations of cameras with electronic flash apparatus; Electronic flash units
- G03B 2215/0521: movable housing, e.g. bounce-light
- G03B 2215/0528: movable reflector, e.g. change of illumination angle or illumination direction
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)

## Abstract

An automatic photographic flash device wherein the amount of light of the flash tube is automatically controlled in response to intensity of light from the direction of the photographic object by means of an electric circuit A flash tube part is movably installed on a main case part containing a battery and the circuit A switch is installed in the device in such a manner that when the flash tube part is moved to a position not directed at the photographic object, the switch causes the circuit to appropriately increase the amount of light discharged by the flash tube when it is actuated.

## Claims

### Claim 1

In an automatic type photoelectric flash device which includes:
a strobo flash tube retained in a flash tube part rotatably installed on a main part,
a capacitor connected to said flash tube, said capacitor being adapted to store electrical energy and to supply current for flashing said tube,
a battery for charging said capacitor,
a flash-terminating circuit operatively associated with said flash tube, and
an electric circuit joined to said flash-terminating circuit for controlling same, said circuit comprising light-receiving means for producing an output in response to light reflected from the direction of a photographic object and switching means responsive to said output reaching a preset level for producing a flash-terminating signal which is applied to the flash-terminating circuit, the improvement comprising:
additional switch means operatively related to said flash tube part and to said electric circuit, said additional switch means actuated in response to the position of said tube part relative to the main part for altering a circuit constant of said electric circuit thereby changing the time required for said electric circuit to produce a flash-terminating signal.

### Claim 2 (depends on 1)

A photographic flash device as set forth in claim 1, wherein said electric circuit includes a first additional capacitor connected in series with the light-receiving means and a second additional capacitor operatively related to said additional switch means and selectively joined to said first additional capacitor in accordance with the actuation of the additional switch means.

### Claim 3 (depends on 1)

A photographic flash device as set forth in claim 1, wherein said electric circuit includes: an additional capacitor connected in series with the light-receiving means, reference voltage generating means, and a comparator for comparing voltage stored by said additional capacitor with said reference voltage for producing said flash-terminating signal; and wherein said electric circuit further includes: a resistor operatively related to said additional switch means, said resistor being selectively joined to said reference voltage generating means to vary the reference voltage in accordance with the actuation of the additional switch means.

### Claim 4 (depends on 1)

A photographic flash device as set forth in claim 1, wherein said energy-storing capacitor is installed in said rotating part.

### Claim 5 (depends on 1)

A photographic flash device as set forth in claim 1, wherein said rotating part includes a click-stop means for defining several preset angles in said rotation.