The charge generated in a light sensing element in semiconductor material by incident radiation is transferred to a charge sink by lowering the potential in the semiconductor material between said light sensing element and the charge sink. When it is desired to accumulate charge in the light sensing element for some purpose, the potential in this intermediate region of semiconductor material is raised to prevent the flow of additional charge to the charge sink region. By adjusting the potential on this intermediate region, a given amount of charge can be allowed to accumulate in the light sensing element while at the same time any additional charge can be allowed to transfer to the charge sink region. The charge packet generated in the light sensing element is read out of the light sensing element in the normal manner.

A charge coupled device for infrared imaging covered with a layer of insulation for absorbing infrared patterns and generating signals due to the temperature dependence of dark current in the charge coupled device.

The disclosure relates to a system for controlling the total charge collected on a charge-coupled imager to, in effect, provide an electronic shuttering action for the charge-coupled imager. The charge-coupled imager works in standard fashion and is normally biased into depletion whereby minority carriers, generated by the light impinging on the imager, are collected in predetermined charge collecting areas or wells, the charges in each well then bring read out in a serial fashion. In order to prevent collection of an excess number of charges, which is equivalent to overexposure in a photographic sense, the majority carriers which are necessarily generated simultaneously with the minority carriers, are collected and integrated so that when a predetermined amount of charge is measured, a shuttering action can take place. When the basic imager is formed from p-type silicon, the majority carrier charges are collected by providing an ohmic contact to the p-type substrate. Two modes ofoperation are disclosed. The first mode is suitable for imaging applications and the second mode is suitable for laser warning receivers.

Analog signals initially are stored in an a linear array such as a charge coupled device (CCD) register. There is provided, for each stage of the linear array, a different column of a CCD matrix, termed here a B register. During a transfer interval, the analog charge signals concurrently are permitted to flow into the columns. As the stages in the B register have much smaller charge storage capacity than the stages in the linear array, the charge signal fills and then overflows successive potential wells of each column until an equilibrium condition is reached. At equilibrium, the number of filled wells in a column will be proportional to the amplitude of the charge signal supplied to that column by the stage of the linear array coupled to the column. The matrix is read by concurrently sensing all of the signals present in one column, and then doing the same for each following column.

An infrared sensitive photodiode having a relatively large optically active area and relatively low capacitance comprises a stripe diode adjacent an optically active area having a thick infrared transparent field oxide over a lightly doped channel stop. The low capacitance photodiode is particularly useful in a range finder device of the type having means for projecting a beam of light to illuminate a spot on an object in a scene, and a linear array of photosensors for detecting the apparent location of the spot in the scene to determine the distance to the object. An improved range finder of this type has an infrared LED with a long narrow beam cross section and an array of stripe photodiodes having shapes similar to the shape of the beam cross section.