Massachusetts Institute of Technology

Raytheon Company

Robert I Frank

Roy Kaplow

Joel L Goodrich

Thomas E Salzer

The invention contemplates a solar-cell construction wherein plural spaced elongate unit cells of an array are formed from a parallel-grooved single wafer or body of substrate material of a first conductivity type, with adjacent sidewalls of adjacent units at each inter-unit groove formation. Both sidewalls at each of a succession of grooves are formed with regions of second conductivity type, and an electrically conductive coating lines each sidewall having a second conductivity type region. A first output-terminal interconnect extends along one margin of the body and has ohmic contact with the coatings of the sidewalls having regions of the second conductivity type. A second output-terminal connection has ohmic contact to the body in a surface region of first conductivity type. Various embodiments are disclosed.

High-intensity solid-state solar-cell device

A semiconductor solar cell capable of converting incident radiation to electrical energy at high efficiency includes a plurality of series-connected unit solar cells formed from a common wafer of semiconductor material. The unit solar cells each include a semiconductor substrate of one conductivity type and a p-n junction formed in the substrate. The light-receiving surface of the cell may have an opaque member thereon, and incident light is directed onto the portion of that surface not covered by the opaque member. A variety of embodiments illustrates the invention.

High-intensity, solid-state solar cell

The invention contemplates improved apparatus for use in a self-tracking optical system for directing highly concentrated solar radiation upon utilization means such as a photovoltaic cell, wherein the full image of the sun covers the exposure surface substantially only when the axis of the optical system is aligned with the sun. Certain structural features associated with the optical system in the vicinity of cell support effectively enlarge the margin of off-axis misalignment within which self-tracking is achievable. At the same time, certain aspects of these features inherently prevent thermal losses which would otherwise be attributable to convection currents of air in the region of heat concentration.

Solar-radiation collection apparatus

A solar cell array, comprised of a plurality of series-connected unit solar cells, formed from a common substrate, is cooled by providing cooling passages between adjacent sidewalls of adjoining unit cells through which a heat transfer medium is transmitted. Transmission of the heat transfer medium through the passages effectively cools the solar cell array as the cooling surfaces provided by the sidewalls of the cooling passages are much larger than the light-receiving surfaces of the cells. Enhanced cooling effectiveness can be accomplished by providing additional cooling passages along the lower surfaces of the unit cells.

Means for effecting cooling within elements for a solar cell array

The invention contemplates a method of making a solar-cell construction wherein plural spaced elongate unit cells of an array are formed from a parallel-grooved single wafer of substrate material of a first conductivity type, with adjacent sidewalls of adjacent units at each inter-unit groove formation. In the transverse succession of such groove formations, the sidewalls of every other groove are formed with regions of a second conductivity type, so that at or near the radiation-exposure surface of each unit there is but one junction between first and second conductivity types. In one general form, all grooves go all the way between upper and lower wafer surfaces, thus defining discrete single-cell units; in another general form, every other groove ends close to but short of the upper surface, thus defining discrete twin-cell units. The units are series-connected by making ohmic connection between the second conductivity-type region of one unit and a first conductivity-type region of an adjacent unit. The construction lends itself to a relatively simple and economical manufacture.

Method of making a solar-cell array

A semiconductor solar-cell array including a plurality of adjacent solar cell segments, each segment comprising a number of series-connected unit solar cells, and the series connected unit solar cells from each segment being electrically connected in parallel with the series-connected unit solar cells from other segments. Concentrated solar radiation is focused on the upper surface of the solar-cell array wherein the periphery of the focused image is contained within the upper surface area. The series-parallel connection of the unit solar cells and solar cell segments provides maximum utilization of incident solar radiation to thereby increase solar cell output. In addition, the series-parallel connection scheme allows the array to operate effectively without imposing stringent requirements as to solar-tracking precision in order to maintain the focused image at a fixed location on the upper surface of the cell.

Solar cell array

A semiconductor solar cell capable of converting incident radiation to electrical energy at high efficiency includes a plurality of series-connected unit solar cells formed on a common wafer of semiconductor material. The unit solar cells each include a semiconductor substrate of one conductivity type and a p-n junction formed in the substrate. The light-receiving surface of the cell may have an opaque member thereon, and incident light may be directed onto the portion of that surface not covered by the opaque member. Various embodiments and methods illustrate the invention.

Method of making a high-intensity solid-state solar cell

A platinum film resistor device and method for making the same. A layer of quartz, deposited upon an insulative substrate preferably silicon, is sputter etched at high power levels to produce etch pits in the surface thereof. A layer of platinum is then deposited over the quartz layer by first sputtering platinum at high power for a relatively short period of time and then completing the layer by continuing to sputter deposit platinum at a lower power. A second layer of quartz is deposited over the layer of platinum and the second layer of quartz masked and chemically etched away in the regions where portions of the platinum layer are to be removed. The exposed platinum and a portion of the second quartz layer are then sputter etched away leaving the platinum in a predetermined configuration. The platinum is then annealed, the second quartz layer removed above the lead bonding pads, and external leads attached. The device is particularly useful in temperature measuring application.

Platinum film resistor device

The invention contemplates a solar-cell construction wherein plural spaced elongate unit cells of an array are formed from a parallel-grooved single wafer of substrate material of a first conductivity type, with adjacent sidewalls of adjacent units at each inter-unit groove formation. In the transverse succession of such groove formations, the sidewalls of every other groove are formed with regions of a second conductivity type, so that at or near the radiation-exposure surface of each unit there is but one junction between first and second conductivity types. In one general form, all grooves go all the way between upper and lower wafer surfaces, thus defining discrete single-cell units; in another general form, every other groove ends close to but short of the upper surface, thus defining discrete twin-cell units. The units are series-connected by making ohmic connection between the second conductivity-type region of one unit and a first conductivity-type region of an adjacent unit. The construction lends itself to a relatively simple and economical method of manufacture, which is also described.

Solar-cell array

An improved solar cell designed for optimum efficiency is comprised of a plurality of series connected unit solar cells formed from a common substrate of semiconductor material. Each unit solar cell has spaced elongate sidewalls, and a 'dead space' area between adjoining sidewalls of adjacent units is made substantially smaller than an active, light receiving area, extending between the opposite sidewalls of each individual unit. In addition, the width of the active area is concisely limited to ensure that radiation incident on the active area is incident at a point which is spaced from the p-n junction of each unit by no more than a predetermined optimum distance. Reducing the 'dead space' area while concisely limiting the width of the active area provides improved solar cell performance without requiring focusing lenses.

Solar cell

A semiconductor solar cell capable of converting incident radiation to electrical energy at high efficiency includes a plurality of series-connected unit solar cells formed on a common wafer of semiconductor material. The unit solar cells each include a semiconductor substrate of one conductivity type and a p-n junction formed in the substrate. The light-receiving surface of the cell may have an opaque member thereon, and incident light is directed onto the portion of that surface not covered by the opaque member. A variety of embodiments illustrates the invention.

High-intensity, solid-state-solar cell device

The invention contemplates improved apparatus for collecting solar radiation and directionally concentrating the same upon utilization means such as a photovoltaic cell system. In the form described, arrayed collecting devices are mounted for individual tracking of maximum solar-energy response at each such cell system, utilizing time-shared access to a microprocessor, and correctional-drive signals uniquely appropriate to the orientation of each collecting device are supplied by the microprocessor on a time-shared basis for the respective components of orientation correction drive means for each collecting device. Since each collecting device is thus automatically correctively positioned for maximum output of its own utilization device, there is an avoidance of precision requirements (a) as to mounting the several collecting devices with respect to each other and (b) as to basic drives to anticipate relative aspect of the sun, as a function of the time of day, or the day of the year, and whatever the earthbound location of the apparatus.

Solar-radiation collection apparatus with tracking circuitry

A photovoltaic or solar cell generator includes a plurality of unit solar cells each having one or more p-n junctions. An optical light-focusing system, which includes an array of lens elements, focuses the incoming radiation into a series of preferably narrow beams that are incident on the surfaces of the unit solar cells at locations lying immediately adjacent but spaced from the p-n junctions.

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Lexington, MA, United States of America

Robert I Frank