Abstract: The electrographic apparatus of a variety wherein a transparent resistive layer is deposited upon an insulative substrate in a manner wherein a rectangularly-shaped resistive layer region is developed having a predetermined conductivity. A conduction band is provided about the periphery of the resistive layer region having a value of conductivity enhanced with respect to the conductivity value of the resistive layer. Discrete resistive elements are positioned intermediate the conduction band and the resistive region and four terminals are provided, one at each of the four corners of the rectangular resistance region. The discrete resistance elements are designed so that a uniform impedance is witnessed with respect to the resistive layer region as witnessed with respect to each of the four terminals. The control system for the device provides for development of coordinate pair information and includes as non-volatile memory retained configurational data for initial set-up of the apparatus by the operator.

Abstract: An improved tracer for use with electrographic surfaces which employs reticle components including crosshairs and a sighting circle which additionally functions to provide capacitive coupling. Formed of a conductive material such as chromium, these components are geometric regular shape and somewhat concentrated at the center portion of the reticle targeting center. As such, the device is capable of achieving a close correspondence between actual physical targeting location and resultant digitized coordinate readout. These components further achieve an avoidance of inaccuracies due to active surface border influences. The reticle-capacitive coupling components are placed on one side of a transparent disk, the opposite or upwardly disposed surface of which is coated with a transparent electrically conductive material such as indium tin oxide.

Abstract: An electrographic apparatus or digitizer has a resistive layer with an active area which operates in conjunction with a stylus or other suitable position locator. An a.c. source or alternatively a signal treatment means is connected to the resistive layer through rows of electrodes and position coordinates of the position locator are developed by the apparatus. Voids or discontinuities are formed in the resistive layer to increase the edge-to-edge resistance of the layer and to provide identical edge-to-edge resistances in the x- and the y-coordinate direction for digitizers which are rectangular and non-square.

Abstract: An electrographic system utilizing a transparent resistive layer which operates in conjunction with a stylus or cross hair cursor excited from an a.c. source to develop coordinate defining electrical signals. Through the utilization of a sequence of border switching arrays, the signals may be collected from the resistive surface in a predetermined sequence and submitted in serial fashion to the input of a signal treatment network. As a consequence, only one such network is required to effect operation of the system. The hand-held cursor is formed including a transparent disk carrying cross hairs which is excited from an a.c. source to very accurately locate coordinate positions upon the resistive surface.

Abstract: An electrographic system utilizing a singular resistive layer which may be transparent in conjunction with a supportive substrate. Through the use of an electromagnetic field generating sytlus in conjunction with coordinate alternating border switching, linear output performance is achieved. With the utilization of sum, difference and divider circuitry in conjuction with received output signals, the system remains immune from voltage variations occasioned in conjunction with the stylus and, thus, the stylus may be operated in varying spaced-relationship from the resistive surface.

Abstract: An improved semiconductor gamma camera is disclosed. The gamma camera includes a p-i-n semiconductor diode which detects the presence and energy of gamma radiation from a source. Typically the source is radioactive material in a patient organ which is detected and then interpreted by a doctor while diagnosing the condition of that organ. The detector includes an improved electrical connection technique to allow the p-i-n diode to be connected to electronic circuitry necessary to provide spatial and energy information. In the improved camera first a passivation layer is deposited on both faces of the p-i-n diode and then a resistive layer is applied to form a reliable easily reproduced electrical contact to the junction. These two layers in combination prevent foreign matter from contacting the semiconductor material comprising the detector while providing interconnection to the electronic circuitry.

Abstract: An improved semiconductor gamma camera is disclosed. The gamma camera includes a p-i-n semiconductor diode which detects the presence and energy of gamma radiation from a source. Typically the source is radioactive material in a patient organ which is detected and then interpreted by a doctor while diagnosing the condition of that organ. The detector includes an improved electrical connection technique to allow the p-i-n diode to be connected to electronic circuitry necessary to provide spatial and energy information. In the improved camera first a passivation layer is deposited on both faces of the p-i-n diode and then a resistive layer is applied to form a reliable easily reproduced electrical contact to the junction. These two layers in combination prevent foreign matter from contacting the semiconductor material comprising the detector while providing interconnection to the electronic circuitry.

Abstract: An improved gamma camera arrangement wherein the spatially defined acceptance of gamma radiation from a source distribution of clinical interest is enhanced by a unique collimator structure. Aliasing frequencies otherwise derived from an orthogonal strip detector array are identified and avoided through a structural geometry wherein collimator resolution is greater than or equal to about 1.7(l), where, l, is the strip spacing of the array.