Patent
1977-02-25
1978-09-05
Adams, Russell E.
354 53, 354 60L, G03B 1720
Patent
active
041124405
ABSTRACT:
A photoreceptor is connected to an operational amplifier to convert the scene brightness to a voltage. The output of the operational amplifier is connected to a light emitting indicator to indicate exposure information. The output of the operational amplifier is also connected to an indicator brightness control circuit which changes the luminance of the light emitting indicator according to the scene brightness so that the luminance of the indicator is increased when the scene brightness is high and vice versa. The control circuit includes a digital signal generator which outputs digital level signals and a selecting circuit which selects the digital signals and controls the luminance of the indicator according to the selected signals. In order to prevent flickering of the indicator, a hysteresis is provided in the selecting circuit.
REFERENCES:
patent: 3955892 (1976-05-01), Numata et al.
patent: 4035815 (1977-07-01), Takahashi
patent: 4048644 (1977-09-01), Numata
patent: 4051491 (1977-09-01), Toyoda
"Designing with TTL Integrated Circuits", Texas Instruments, Aug. 21, 1975, p. 261 and p. 267.
Adams Russell E.
Fuji Photo Optical Co., Ltd.
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