Browse Prior Art Database

Rod Height Control for E Beam Evaporation System

IP.com Disclosure Number: IPCOM000085319D
Original Publication Date: 1976-Mar-01
Included in the Prior Art Database: 2005-Mar-02
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Clemens, WG: AUTHOR [+3]

Abstract

An apparatus as shown in the figure accurately positions a rod of the deposition material, such that an electron beam, not shown, can strike and create a molten pool at the top of the rod for vapor deposition.

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Rod Height Control for E Beam Evaporation System

An apparatus as shown in the figure accurately positions a rod of the deposition material, such that an electron beam, not shown, can strike and create a molten pool at the top of the rod for vapor deposition.

A laser generates a beam of light that is pointed at the molten pool. The light not intercepted by the molten pool is directed through an aperture and a filter before impinging on a light sensor. The light sensor, in turn, operates a controller to activate a rod driver system to position the rod up or down, as required, such that the E-beam apparatus, not shown, can direct its electron beam onto the top of the rod to maintain a predetermined depth of the molten pool.

The laser light beam is preferably of a narrow bandwidth so that the filter can be of a narrow bandwidth to pass only the laser beam, while filtering the light emitted by the molten metal in the pool. The aperture assists in blocking this scattered light from being sensed by the light sensor. The light sensor is preferably located a distance from the pool to eliminate the sensing of the scattered light, while having little effect on the laser light beam.

The signal from the light sensor is proportioned to the portion of the laser beam not obscured by the opaque pool. By setting the controller accordingly, the rod driver can drive the rod up and down through a rack and pinion drive, for instance, commensurate with the amount of light striking the...