International Business Machines Corporation

James Cleary McGroddy

Joseph M Blum

Frank F Fang

Bruce A Scott

Billy L Crowder

Peter S Zory, Jr

James Alden Van Vechten

Eric Gung Lean

A digital photodetector circuit having a photosensing stage connected to a depletion mode field effect transistor forming an inverter stage, increased sensitivity is achieved by then coupling the output of the photo inverter to a second photo inverter whose photosensitive element serves as the active load of an enhancement mode field effect transistor in the inverter stage. The circuit is readily fabricated in integrated structures. The circuit performance may be adjusted for responsiveness to light sensitivity and to provide selectable electrical output signal level and impedance matching including bistable performance.

Digital photodetectors

This disclosure obtains printing and displaying of information stored as a pattern of orifices in a colored liquid film established on the interstices of a screen-mesh member. A laser beam is used to effect removal of the film at each selected interstice either by puncturing the film thereat or vaporizing a portion thereof so that reactive surface tension force displaces the remainder of the film. The screen is moved in coordination with the writing thereon of the information pattern so that the area upon which the information is established may be presented sequentially to a displaying station and to a printing station. At the displaying station, light is either transmitted through the orifices established in the colored liquid film or is reflected from the film left in the unwritten interstices onto a display screen as a pattern of information either as a positive or a negative image of the actual information content established in the screen-mesh. The information written in the film on the screen-mesh may then be conveniently printed by technology of aerosol-mist via the orifices established at the interstices. Alternatively, the information written onto the screen-mesh via the films may be printed directly therefrom by the laser beam. Finally, both the displaying and the printing may be accomplished at the same station as the writing by a convenient arrangement of displaying screen and printing mechanism.

Printing and displaying technology using selective laser beam pricking

An array of closely spaced injection lasers is mounted upon a common substrate of grooved semiconductor or insulating material, with the active (hot) layers of the lasers as close as possible to the substrate. Individual grooves of relatively large cross-sectional area are formed in the portions of the substrate upon which the respective lasers are seated, each of these grooves underlying a respective one of the lasers, and each groove is filled with a material that has high thermal and electrical conductivity, thereby providing a massive beam lead which also serves to dissipate heat generated by the respective laser. The walls of the grooves are treated to provide electrical isolation between the beam leads, so that these leads can be used to establish individual switching connections to the active elements of the respective lasers. With this arrangement, individual lasers in the array can be independently switched on and off as needed during a multiple beam scan, and each laser has an individual heat sink for efficiently dissipating the heat that it generates.

Injection laser array

A method of depositing conducting patterns on a large area surface is disclosed. The method is characterized by photochemically depositing an electrically conducting organic .pi.-electron donor compound on an insulating surface and selectively depositing a metal onto the established conductive pattern while simultaneously removing the organic film.

Method of depositing metal conducting patterns on large area surfaces

An injection laser, which is chemically etched to provide mirror-like surfaces, also is provided with a chirped diffraction grating. The latter grating, which is etched in the injection laser, combines with the chemically etched sides to provide laser emission in a direction substantially parallel to the current flowing through the laser. As an alternative to the chirped diffraction grating, waveguides are included in the resulting folded cavity laser. Either of the above structures relaxes the fabrication tolerance in the inclined surfaces etched in the laser relative to known folded cavity lasing structures.

Folded cavity injection laser

An injection laser, whose sides are chemically etched to produce facing 45.degree. mirrors, can be made to emit lasing light in the same direction as current going through the p-n junction. A two dimensional array of lasers is produced wherein the location of each laser is uniformly spaced from an adjacent laser.

Two-dimensional integrated injection laser array

A method for improving the current confinement capacity of a double heterojunction laser by using a high energy implantation of oxygen in the regions of an injection laser surrounding the active region of such laser so as to make such regions semi-insulating.

Growing community of inventors

Putnam Valley, NY, United States of America

James Cleary McGroddy