High-sensitive optical reading apparatus and method of reading optical information

Claim 2

An optical reading apparatus for converting optically readable information into an electrical signal, comprising: a charge transfer device image sensor (8) for converting optical information into an electrical signal, said image sensor having a plurality of optical imaging elements (8a) arranged in an array, said optical imaging elements being electrically divided into two or more groups so that signal charges from one group can be derived simultaneously, said image sensor having an output circuit (8d, 8e, 8f) responsive to a plurality of electrical signals each produced by each of said two or more groups so that said plurality of electrical signals are combined as a single output signal; means (17, 18, 9) for driving said image sensor so that said image sensor performs electronic scanning by deriving signal charges from said optical imaging elements; and means (10, 11, 12, 13, 14, 15, 16) responsive to said output signal from said image sensor (8) for processing the same to produce an electrical signal indicative of the read information, characterized in that the driving means (17, 18, 9) produces at least two clocks (φ TG1' $TG2) which are shifted by an amount of time from each other, said at least two clocks being fed to said image sensor (8) in such a manner that at least two groups of said optical imaging elements (8a) are driven alternately.

Claim 3

An optical reading apparatus for converting optically readable information into an electrical signal, comprising: a charge transfer device image sensor (8) for converting optical information into an electrical signal, said image sensor having a plurality of optical imaging elements (8a) arranged in an array, said optical imaging elements being electrically divided into two or more groups so that signal charges from one group can be derived simultaneously, said image sensor having an output circuit (8d, 8e, 8f) responsive to a plurality of electrical signals each produced by each of said two or more groups so that said plurality of electrical signals are combined as a single output signal; means (17, 18, 9) for driving said image sensor so that said image sensor performs electronic scanning by deriving signal charges from said optical imaging element, said means producing at least two clocks (φ TG1' φ TG2 ) which are fed to said image sensor so that at least two groups of said optical imaging elements are driven; and means (10, 11, 12, 13, 14, 15, 16) responsive to said output signal from said image sensor for processing the same to produce an electrical signal indicative of the read information, characterized by means (16, 19) for controlling the means (9) for driving so that said at least two clocks (φ TG1 , φ TG2 ) have one of first and second time relationships therebetween, said at least two clocks being shifted by an amount of time from each other when in the first time relationship, and said at least two clocks being of the same timing when in the second time relationship, said two clocks having the first time relationship therebetween causing said image sensor (8) to derive signal charges of one group after signal charges of another group have been derived, and said two clocks having the second relationship therebetween causing said image sensor to derive signal charges of all groups simultaneously.

Claim 4

An optical reading apparatus for converting optically readable information into an electrical signal, comprising: a charge transfer device image sensor (8) for converting optical information into an electrical signal, said image sensor having a plurality of optical imaging elements (8a) arranged in an array, said optical imaging elements being electrically divided into two or more groups so that signal charges from one group can be derived simultaneously, said image sensor having an output circuit (8d, 8e, 8f) responsive to a plurality of electrical signals each produced by each of said two or more groups so that said plurality of electrical signals are combined as a single output signal; means (17, 18, 9) for driving said image sensor so that said image sensor performs electronic scanning by deriving signal charges from said optical imaging element, said means producing at least two clocks (φ TG1' φ TG2 ) which are fed to said image sensor so that at least two groups of said optical imaging elements are driven; and means (10, 11, 12, 13, 14, 15, 16) responsive to said output signal from said image sensor for processing the same to produce an electrical signal indicative of the read information, characterized by means (16, 19) for controlling the means (9) for driving so that said at least two clocks (φ TG1 , φ TG2 ) have one of first and second time relationships therebetween, said at least two clocks being shifted by an amount of time from each other when in the first time relationship, and said at least two clocks being of the same timing when in the second time relationship, said two clocks having the first time relationship therebetween causing said image sensor (8) to derive signal charges of one group after signal charges of another group have been derived, and said two clocks having the second relationship therebetween causing said image sensor to derive signal charges of all groups simultaneously.

Claim 5

An optical reading apparatus as claimed in Claim 1 or 2, characterized in that said optical imaging elements are divided into two groups so that one group includes optical imaging elements of odd number and the other includes optical imaging elements of even number, wherein odd and even numbers indicate the position of each optical imaging element viewed from one end of the array (8a).

Claim 6

An optical reading apparatus as claimed in Claim 1 or 2, characterized in that said image sensor (8) comprises a charge-coupled device.

Claim 7

An optical reading apparatus as claimed in Claim 1 or 2, characterized in that said two clocks (φ TG1' φ TG2 ) are first and second sequences of pulses, the pulses of the second sequence being delayed from the pulses of the first sequence by an amount sufficient to cause the signal charges, derived in response to a pulse of said first sequence, to be read out from said image sensor within a time period between said pulse of said first sequence and a subsequently coming pulse of said second sequence.

Claim 8

An optical reading apparatus as claimed in Claim 5, characterized in that the pulses of the second sequence (φ TG2 ) are delayed from the pulses of the first sequence (φ TG1 ) by 180 degrees wherein the pulses of the first sequence have a period of 360 degrees.

Claim 11

A method as claimed in Claim 7, characterized in that the number of said groups is two so that signal charges of odd number and signal charges of even number are respectively derived at different timings, wherein odd and even numbers indicate the position of each optical imaging element viewed from one end of the array (8a).

Claim 12

A method as claimed in Claim 7, characterized in that the step of causing comprises a step of applying to said image sensor (8) first and second sequences (φ TG1' φ TG2 ) of pulses, the pulses of the second sequence (φ TG2 ) being delayed from the pulses of the first sequence (φ TG1 ) by an amount sufficient to cause the signal charges, derived in response to a pulse of said first sequence, to be read out from said image sensor (8) within a time period between said pulse of said first sequence and a subsequently coming pulse of said second sequence.