Electronic calculator having an indicator blanking circuit

Claim 2

An electronic calculator comprising: arithmetic operation means having a signal loop including at least a first register, an adder and a buffer circuit, and a second register connected to said adder so that the latter may add signals from said first and second registers, indicating means including an indicator and an indicator driving circuit having a decoder circuit which is connected to said buffer circuit to operate said indicator driving circuit in response to signals supplied to said decoder circuit from said adder by way of said buffer circuit, control means for producing a condition signal at least during a substantial portion of the period of an operation by said arithmetic operation means, and circuit means operative in response to said condition signal to deactivate said indicator driving circuit for at least said portion of the operation period of said arithmetic operation means.

Claim 3

An electronic calculator according to claim 1, wherein said indicator has at least first and second electrodes, and said indicator driving circuit is connected to one of said first and second electrodes.

Claim 4

An electronic calculator according to claim 2, wherein said first and second electrodes are an anode and a cathode, respectively.

Claim 5

An electronic calCulator comprising: arithmetic operation means having a signal loop including at least a first register, an adder and a buffer circuit, and a second register connected to said adder so that the latter may add signals from said first and second registers; an indicator including a plurality of anodes and a plurality of cathodes associated with each of said anodes; anode drive circuit means emitting anode drive signals for driving said anodes sequentially; cathode drive circuit means including decoder circuit means connected with said buffer circuit for emitting cathode drive signals to activate said indicator and produce a corresponding indication by means of a discharge between the driven anode and cathode in response to signals supplied to said decoder circuit means from said adder by way of said buffer circuit; first circuit means deactivating said indicator at the termination of each of said anode drive signals for dissipating ions resulting from said discharge between the previously driven anode and cathode; control means for producing a condition signal at least during a substantial portion of the period of an operation by said arithmetic operation means; and second circuit means operative in response to said condition signal for deactivating said indicator and thereby avoiding a flickering indication by said indicator at least during said portion of the operation period of said arithmetic operation means.

Claim 6

An electronic calCulator comprising: arithmetic operation means having a signal loop including at least a first register, an adder and a buffer circuit, and a second register connected to said adder so that the latter may add signals from said first and second registers; an indicator including a plurality of anodes and a plurality of cathodes associated with each of said anodes; anode drive circuit means emitting anode drive signals for driving said anodes sequentially; cathode drive circuit means including decoder circuit means connected with said buffer circuit for emitting cathode drive signals to activate said indicator and produce a corresponding indication by means of a discharge between the driven anode and cathode in response to signals supplied to said decoder circuit means from said adder by way of said buffer circuit; first circuit means deactivating said indicator at the termination of each of said anode drive signals for dissipating ions resulting from said discharge between the previously driven anode and cathode; control means for producing a condition signal at least during a substantial portion of the period of an operation by said arithmetic operation means; and second circuit means operative in response to said condition signal for deactivating said indicator and thereby avoiding a flickering indication by said indicator at least during said portion of the operation period of said arithmetic operation means.

Claim 7

An electronic calculator according to claim 4; further comprising means for substantially reducing the potential difference between the associated anodes and cathodes during the deactivation of said indicator.

Claim 8

An electronic calculator according to claim 4; wherein said said indicator includes switching means interposed between each of cathodes and ground and being adapted to be turned on by the respective cathode drive signals, and said first circuit means includes a transistor interposed between said switching means and ground and being normally conductive, and pulse signal generating means for producing a pulse signal rendering said transistor non-conductive for a relatively short period at the commencement of each of said anode driving signals.

Claim 9

An electronic calculator according to claim 6; in which said second circuit means includes means responsive to said condition signal for rendering said transistor non-conductive during said portion of the operation period of said arithmetic operation means.

Claim 10

An electronic calculator according to claim 7; further comprising means for substantially reducing the potential difference between the associated anodes and cathodes upon said transistor being rendered non-conductive.