Photosensitive tracking device with A-C readout of position of image on special photocell

Claim 2

Radiant energy sensing apparatus comprising: a radiant energy responsive photoconductive element having a surface, a plurality of electrical contacts making electrical ohmic connection with said element in mutually spaced relation on said element, a plurality of out-of-phase sources of alternating current, each of said plurality of sources being simultaneously connected to and energizing a different pair of said contacts, said pairs of contacts being oriented along non-parallel lines in relation to each other, a sensing contact being one of said plurality of contacts, said sensing contact being disposed within the region bounded by the contacts of said pairs, an output terminal connected to said sensing contact to provide a plurality of out-of-phase continuous output signals of alternating current, means for separating said plurality of continuous output signals to provide a separate continuous output signal corresponding to each out-of-phase source, the phase and amplitude of each separate output signal relative its corresponding source being indicative of the position of impinging radiant energy on the surface of said element.

Claim 3

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, a plurality of electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced relation over said area including at least four contacts in mutually spaced quadrilateral configuration, one pair of said contacts being oriented along a line orthogonal to the other pair of said contacts, a plurality of sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being out of phase and establishing simultaneous voltage gradients within said photoconductive material along orthogonally oriented lines, a sensing contact centrally disposed within said quadrilateral configuration in electrical ohmic contact with said photoconductive material, and output means electrically coupled to said centrally disposing sensing contact to provide a continuous electrical signal, means for sensing the phase and amplitude of said signal with respect to said out-of-phase sources, the in-phase amplitude and polarity of said signal with respect to each source being responsive to the position of impinging radiant energy on the surface of said element relative the terminals to which each source is connected.

Claim 4

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, a plurality of electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced relation over said area including at least four contacts in mutually spaced quadrilateral configuration, one pair of said contacts being oriented along a line orthogonal to the other pair of said contacts, a plurality of sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being out of phase and establishing simultaneous voltage gradients within said photoconductive material along orthogonally oriented lines, a sensing contact centrally disposed within said quadrilateral configuration in electrical ohmic contact with said photoconductive material, and output means electrically coupled to said centrally disposing sensing contact to provide a continuous electrical signal, means for sensing the phase and amplitude of said signal with respect to said out-of-phase sources, the in-phase amplitude and polarity of said signal with respect to each source being responsive to the position of impinging radiant energy on the surface of said element relative the terminals to which each source is connected.

Claim 5

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, four electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced quadrilateral configuration, each pair of said contacts being located at opposite corners of said quadrilateral configuration, two sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being in phase quadrature and establishing voltage gradients within said photoconductive mateRial, a sensing contact centrally disposed within said quadrilateral configuration in electrical ohmic contact with said photoconductive material, and output means coupled to said centrally disposed sensing contact to provide a continuous signal indicative of the position of impinging radiant energy on the surface of said element, said output means including two phase sensitive rectifiers each having an input connected to said sensing contact, one of said rectifiers having one of said sources connected as its other input whereby said one rectifier provides a first continuous voltage output, the other of said rectifiers having the other of said sources connected at its other input whereby said other rectifier provides a second continuous voltage output.

Claim 6

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, four electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced quadrilateral configuration, each pair of said contacts being located at opposite corners of said quadrilateral configuration, two sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being in phase quadrature and establishing voltage gradients within said photoconductive mateRial, a sensing contact centrally disposed within said quadrilateral configuration in electrical ohmic contact with said photoconductive material, and output means coupled to said centrally disposed sensing contact to provide a continuous signal indicative of the position of impinging radiant energy on the surface of said element, said output means including two phase sensitive rectifiers each having an input connected to said sensing contact, one of said rectifiers having one of said sources connected as its other input whereby said one rectifier provides a first continuous voltage output, the other of said rectifiers having the other of said sources connected at its other input whereby said other rectifier provides a second continuous voltage output.

Claim 7

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, four electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced quadrilateral configuration, one pair of said contacts being oriented along a line orthogonal to the other pair of said contacts, two sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being in phase quadrature and establishing voltage gradients within said photoconductive material along orthogonally oriented lines, a sensing contact centrally disposed within said quadrilateral configuration in ohmic electrical contact with said photoconductive material, and output means coupled to said centrally disposed sensing contact to provide a continuous signal indicative of the position of impinging radiant energy on the surface of said element, said output means including at least two phase-sensitive detectors each having an input connected to said sensing contact, one of said detectors having one of said sources of alternating current applied as another of its inputs, said one detector having an output voltage and phase indicative of said position relative the pair of contacts to which said one source is connected, the other of said detectors having the other of said sources of alternating current as another of its inputs, said other detector having an output voltage and phase indicative of said position relative the pair of contacts to which said other source is connected.

Claim 8

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, four electrical contacts making electrical ohmic connection with said photoconductive material in mutually spaced quadrilateral configuration, one pair of said contacts being oriented along a line orthogonal to the other pair of said contacts, two sources of alternating current, each of said sources connected to a different pair of said contacts, said sources being in phase quadrature and establishing voltage gradients within said photoconductive material along orthogonally oriented lines, a sensing contact centrally disposed within said quadrilateral configuration in ohmic electrical contact with said photoconductive material, and output means coupled to said centrally disposed sensing contact to provide a continuous signal indicative of the position of impinging radiant energy on the surface of said element, said output means including at least two phase-sensitive detectors each having an input connected to said sensing contact, one of said detectors having one of said sources of alternating current applied as another of its inputs, said one detector having an output voltage and phase indicative of said position relative the pair of contacts to which said one source is connected, the other of said detectors having the other of said sources of alternating current as another of its inputs, said other detector having an output voltage and phase indicative of said position relative the pair of contacts to which said other source is connected.

Claim 9

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, said material having a plurality of electrical ohmic contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical ohmic connection with said material, and output means connected to said sensing contact to provide a continuous output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including at least two phase sensitive detectors having an input of each connected to said sensing contact, one of said detectors having said source of alternating current of reference phase applied as another input whereby saId one detector output provides a continuous voltage output whose amplitude and polarity indicate the location of said impinging radiant energy relative to said one pair of contacts, the other of said detectors having said source of alternating current of quadrature phase applied as another input whereby said other detector output provides a continuous voltage output whose amplitude and polarity indicate the location of said impinging radiant energy relative to said other pair of contacts.

Claim 10

Radiant energy sensing apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, said material having a plurality of electrical ohmic contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical ohmic connection with said material, and output means connected to said sensing contact to provide a continuous output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including at least two phase sensitive detectors having an input of each connected to said sensing contact, one of said detectors having said source of alternating current of reference phase applied as another input whereby saId one detector output provides a continuous voltage output whose amplitude and polarity indicate the location of said impinging radiant energy relative to said one pair of contacts, the other of said detectors having said source of alternating current of quadrature phase applied as another input whereby said other detector output provides a continuous voltage output whose amplitude and polarity indicate the location of said impinging radiant energy relative to said other pair of contacts.

Claim 11

Target tracking apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, carriage means on which said detector element is mounted, said carriage means being mounted for movement with two degrees of freedom, said material having a plurality of electrical contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical connection with said material, output means connected to said sensing contact to provide an output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including a phase sensitive drive means responsive to the reference and quadrature voltage components of said output signal, and said drive means adapted to move said carriage means in response to said output voltage components to a position where radiant energy impinging on said material from a remote source produces a zero output voltage.

Claim 12

Target tracking apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, carriage means on which said detector element is mounted, said carriage means being mounted for movement with two degrees of freedom, said material having a plurality of electrical contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical connection with said material, output means connected to said sensing contact to provide an output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including a phase sensitive drive means responsive to the reference and quadrature voltage components of said output signal, and said drive means adapted to move said carriage means in response to said output voltage components to a position where radiant energy impinging on said material from a remote source produces a zero output voltage.

Claim 13

Target tracking apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, carriage means on which said detector element is mounted, said carriage means being mounted for movement with two degrees of freedom, said material having a plurality of electrical contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical connection with said material, output means connected to said sensing contact to provide an output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including a phase sensitive drive means responsive to the reference and quadrature voltage components of said output signal, said drive means adapted to move said carriage means in response to said output voltage components to a position where radiant energy impinging on said material from a remote source produces a zero output voltage, null balancing mEans connected to said output means to provide a zero output voltage in the absence of said impinging radiant energy, and said balancing means including means for introducing reference and quadrature voltages from said sources into said output means of phase and amplitude sufficient to cancel the residual output voltage from said sensing contact.

Claim 14

Target tracking apparatus comprising: a radiant energy responsive detector element including a support having a surface area and a layer of photoconductive material on the surface of said support, carriage means on which said detector element is mounted, said carriage means being mounted for movement with two degrees of freedom, said material having a plurality of electrical contacts, four of said contacts being arranged in a mutually spaced quadrilateral configuration, one pair of said four contacts being oriented along a line orthogonal to the other pair of said four contacts, a source of alternating current of reference phase having a push-pull balanced voltage output with respect to a ground connection of said source, said reference phase source output being connected to one pair of contacts, a source of alternating current of quadrature phase having a push-pull balanced voltage output with respect to a ground connection of said source, said quadrature phase source output being connected to the other pair of contacts, a sensing contact centrally disposed within said quadrilateral configuration making electrical connection with said material, output means connected to said sensing contact to provide an output signal relative to ground potential indicative of the position of impinging radiant energy on the surface of the element, said output means including a phase sensitive drive means responsive to the reference and quadrature voltage components of said output signal, said drive means adapted to move said carriage means in response to said output voltage components to a position where radiant energy impinging on said material from a remote source produces a zero output voltage, null balancing mEans connected to said output means to provide a zero output voltage in the absence of said impinging radiant energy, and said balancing means including means for introducing reference and quadrature voltages from said sources into said output means of phase and amplitude sufficient to cancel the residual output voltage from said sensing contact.