To facilitate reading of digital indication of time in a digital clock by turning on a light source with proper brightness.
In a digital clock indicating time in digital by turning on a light source, a controller circuit 50 making variable duty ratio which is a ratio of turn-on time of the light source to total indication time of digital indication. By changing the duty ratio of the light source with the controller circuit according to various conditions, the brightness of the digital indication is made to be proper. For example, a dial plate 24 digital-indicating time by transmitting the light when turning on the light source is provided based on time data 52 and the output signal of a provided light sensor 55. When each figure indication digitally indicating, is turned on by shifting in turn for a light source outage time X based on the light transmission of the dial plate and based on the voltage detection data 58, the downtime of the light source is changed so that the duty ratio is made variable in the controller circuit.
TOYAMA KAZUHISA
IMAI TOSHIYUKI
HAYASHI KENTARO
SATO HIROYUKI
HASEGAWA MASAHIDE
| JPS5280875A | 1977-07-06 | |||
| JPS5799192U | 1982-06-18 | |||
| JPS62199696U | 1987-12-19 | |||
| JPS5162068A | 1976-05-29 | |||
| JPS62124589U | 1987-08-07 | |||
| JP2003271100A | 2003-09-25 | |||
| JPS5327072A | 1978-03-13 | |||
| JPH02147015A | 1990-06-06 |
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