Portable bar code reader utilizing pulsed LED array

Claim 1

A bar code reader comprising: an LED array containing at least one LED which is connected between first and second terminals and is adapted when energized to direct light upon a bar code; a linear CCD array adapted to receive a portion of the light directed by the LED array onto the bar code and thereafter reflected from the bar code onto the CCD array, the CCD array receiving such reflected light and absorbing the energy therein, this energy having a value at which the CCD array will accumulate a sufficiency of electrical charge during a first period, the CCD array delivering said charge to a shift register during an immediately following second period; means connected between said first and second terminals to energize the LED array to emit at least one pulse of light during a fraction of said first period, the value of energy contained in the light pulse being sufficient to charge the CCD array, said means including first and second transistor switches which act in opposite sense so that when the first switch is conductive, the second switch is non-conductive, and when the second switch is conductive, the first switch is non-conductive, and also including a pulse generator to intermittently supply a control pulse to said first switch, the generator and the first switch having a common ground; and a circuit for controlling the timing of the first and second periods and supplying a control signal to said means to establish proper timing.