Radiation sensing and signal transfer circuits

Claim 2

In combination: a radiation sensing element; charge storage means associated with said element for receiving and storing a charge proportional to the radiation reaching said element; charge limiting means coupled to said element for limiting the amount of charge stored at said charge storage means to a predetermined level; an output circuit; normally disabled gate circuit means coupled between said charge storage means and said output circuit; and means for concurrently disconnecting said charge limiting circuit from said charge storage means and enabling said gate circuit means.

Claim 3

In combination: a radiation sensing element; charge storage means associated with said element for receiving and storing a charge proportional to the radiation reaching said element; charge limiting means coupled to said element for limiting the amount of charge stored at said charge storage means to a predetermined level; an output circuit; normally disabled gate circuit means coupled between said charge storage means and said output circuit; and means for concurrently disconnecting said charge limiting circuit from said charge storage means and enabling said gate circuit means.

Claim 4

In combination: a radiation sensing element; charge storage means associated with said element for receiving and storing a charge proportional to the radiation reaching said element; charge limiting means coupled to said element for limiting the amount of charge stored at said charge storage means to a predetermined level; an output circuit; normally disabled gate circuit means coupled between said charge storage means and said output circuit; and means for concurrently disconnecting said charge limiting circuit from said charge storage means and enabling said gate circuit means.

Claim 5

In the combination as set forth in claim 1, further including means for shifting the voltage level at said storage means when said charge limiting circuit is disconnected from said storage means.

Claim 6

In the combination as set forth in claim 2 wherein said charge limiting means includes means for preventing the accumulation of charge during a first time interval and for limiting the maximum amount of charge accumulated during a second time interval.

Claim 7

The combination comprising: photoresponsive means for producing a flow of charge in response to incidEnt light; storage means associated with said photoresponsive means for storing the charge produced thereby; an output circuit; charge transfer circuit means coupled between said storage means an said output circuit for transferring the charge in said storage means to said output circuit in response to a control signal; and limiting means coupled to said photoresponsive means for preventing the accumulation of charge during a first time interval and for limiting the maximum amount of charge accumulated during a second time interval.

Claim 8

The combination comprising: photoresponsive means for producing a flow of charge in response to incidEnt light; storage means associated with said photoresponsive means for storing the charge produced thereby; an output circuit; charge transfer circuit means coupled between said storage means an said output circuit for transferring the charge in said storage means to said output circuit in response to a control signal; and limiting means coupled to said photoresponsive means for preventing the accumulation of charge during a first time interval and for limiting the maximum amount of charge accumulated during a second time interval.

Claim 9

The combination as set forth in claim 4 wherein said photoresponsive means comprises a diode having an anode and cathode and said storage means comprises the capacitance between said anode and cathode exhibited by said diode.

Claim 10

The combination as claimed in claim 5 wherein said output circuit and said charge transfer circuit are of the bucket brigade type.

Claim 11

The combination as claimed in claim 5 wherein said output circuit and said charge transfer circuit are of the charge coupled type.

Claim 12

The combination comprising: photo responsive means for producing a flow of charge in response to incident light; charge storage means associated with said means for storing said charges and thereby developing a potential corresponding to the accumulated charge; charge transfer circuit means, including the source-drain path of at least one gating transistor, coupled between said photoresponsive means and an output register for selectively transferring said accumulated charges to said output register; and limiting means coupled to said photoresponsive means for preventing the accumulation of charge during a first time interval and for limiting the maximum level of said potential due to the accumulation of said charges during a second time interval.

Claim 13

The combination comprising: photo responsive means for producing a flow of charge in response to incident light; charge storage means associated with said means for storing said charges and thereby developing a potential corresponding to the accumulated charge; charge transfer circuit means, including the source-drain path of at least one gating transistor, coupled between said photoresponsive means and an output register for selectively transferring said accumulated charges to said output register; and limiting means coupled to said photoresponsive means for preventing the accumulation of charge during a first time interval and for limiting the maximum level of said potential due to the accumulation of said charges during a second time interval.

Claim 14

The combination as claimed in claim 8 wherein said photoresponsive means is a photodiode having its cathode connected to a first terminal and its anode connected to a second terminal; wherein said limiting means includes a limiting transistor having its source connected to said anode and its gate and drain connected to a third terminal; and wherein said limiting means also includes means for during said first time interval applying a first potential to said third terminal for causing said limiting transistor to conduct for preventing the accumulation of charge at the anode of said photodiode and for during said second time interval applying a second potential to said terminal for preventing the conduction of said transistor until the potential at said anode exceeds said second potential.

Claim 15

The combination as claimed in claim 9 wherein said gating transistor of said charge transfer means is connected at its source to said anode, at its drain to an input node of said output register and at its gate to a source of pulses.

Claim 16

The combination as claimed in claim 10 further including means for applying a pulse of given amplitude to the cathode of said photodiode whereby the pulse is coupled through the reverse biased junction of the diode for causing its anode potential to rise; and means for concurrently increasing the potential at said third terminal an amount equal to said given amount for turning off said limiting transistor.