Abstract A data display apparatus using a plurality of light-emitting diodes (19), (20) as display elements to display characters or figures in the form of a chain of dots. The light-emitting diodes (19), (20) are controlled by a photoelectric converter circuit (2) and by pulse oscillation circuits (4), (6) that are connected to the photoelectric converter circuit (2) and that produce pulse signals by changing the ratio of pulse output time in response to output signals of the circuit (2) so that brightness of the diodes is tuned to the ambient brightness (1). A level detector circuit (8) is also provided to change the kinds and numbers of light-emitting diodes that are to be driven.
1 . A data display apparatus which comprises a photoelectric converter circuit which converts the received light into electric signals and pulse oscillation circuits which receive the output signal of the photoelectric converter circuit to change the duty cycle of the output pulses according to the output signal in order to decrease the duty cycle of the output pulses when the ambient brightness is low and to increase them when the ambient brightness is high so that LED radiation brightness can be automatically tuned to the ambient brightness.
Claim 2
Dependent Claim
88 words
1 . A data display apparatus which comprises a photoelectric converter circuit which converts the received light into electric signals and pulse oscillation circuits which receive the output signal of the photoelectric converter circuit to change the duty cycle of the output pulses according to the output signal in order to decrease the duty cycle of the output pulses when the ambient brightness is low and to increase them when the ambient brightness is high so that LED radiation brightness can be automatically tuned to the ambient brightness.
Claim 3
Dependent Claim
54 words
A data display apparatus in accordance with claim 1, in which a level detector circuit is also provided to produce an active-level output signal when the output signal level of said photoelectric converter circuit exceeds a specified cutoff point so that both the kinds (radiation colors) and number of LEDs used can be changed.
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