Title:
FLASH LIGHT EMISSION DEVICE WITH AUTOMATIC DIMMING FUNCTION
Document Type and Number:
Japanese Patent JPH01172821
Kind Code:
A
Abstract:
PURPOSE:To reduce the excessive light emission of flash light by varying a reference signal to be compared with the integral signal of subject reflected light with flash light emission time, and advancing a light emission stopping operation time point according to the distance to a subject. CONSTITUTION:In short-distance photography, the point of time when an integral signal curve C and the reference signal A meets each other is T2 and a light emission stop signal is outputted at this point of time, but a conventional reference signal B meets the integral signal curve C at a point T3 in short-distance photography and the light emission stop signal is outputted at this point of time. Namely, the generation of the light emission stop signal is advanced by a period T2-T3. In long-distance photography, on the other hand, the generation of the light emission stop signal is advanced by a period T4-T5, which is shorter than the period T2-T3 in the short-distance photography. Thus, the light emission stop operation point T2 is advanced as compared with a conventional point T3 and a flash light emission curve E is obtained. Consequently, the excessive light emission quantity is reduced as compared with a conventional flash light emission curve F.
Inventors:
OKI KENJI
SEKIDO KEIZO
SEKIDO KEIZO
Application Number:
JP32952287A
Publication Date:
July 07, 1989
Filing Date:
December 28, 1987
Export Citation:
Assignee:
STANLEY ELECTRIC CO LTD
International Classes:
G03B15/05; H05B41/32; (IPC1-7): G03B15/05; H05B41/32
Domestic Patent References:
| JP58163936B | ||||
| JPS56151919A | 1981-11-25 | |||
| JP55113525B | ||||
| JPS50153632A | 1975-12-10 |
Attorney, Agent or Firm:
Koji Koike
Previous Patent: POS TERMINAL DEVICE WITH LIQUID CRYSTAL PANEL
Next Patent: VARIABLE LIGHT QUANTITY TYPE FLASH LIGHT EMISSION DEVICE
Next Patent: VARIABLE LIGHT QUANTITY TYPE FLASH LIGHT EMISSION DEVICE