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LASERONA

IP.com Disclosure Number: IPCOM000026341D
Original Publication Date: 1991-Jun-30
Included in the Prior Art Database: 2004-Apr-05
Document File: 2 page(s) / 112K

Publishing Venue

Xerox Disclosure Journal

Abstract

Photo ionization is the key mechanism in providing seed electrons for corona discharge. In a self sustaining corona discharge, the light emitted from the avalanche of the corona near the wire reaches locations outside the sheath region of the corona. These photons produce ionization of the air molecules resulting in free electrons moving toward the positive wire, and seeding the avalanche process resulting in positive ions which move away from the positive wire toward the other electrode.

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XEROX DISCLOSURE JOURNAL

LASERONA

Gerald A. Domoto Robert J. Kleckner

Proposed Classification US. C1.355/221
Int. C1. G03g 15/02

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XEROX DISCLOSURE JOURNAL - Vol. 16, No. 3 May/June 1991 181

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LASERONA(Cont'd)

Photo ionization is the key mechanism in providing seed electrons for corona discharge. In a self sustaining corona discharge, the light emitted from the avalanche of the corona near the wire reaches locations outside the sheath region of the corona. These photons produce ionization of the air molecules resulting in free electrons moving toward the positive wire, and seeding the avalanche process resulting in positive ions which move away from the positive wire toward the other electrode.

Referring to the Figure, by using an external source or light (i.e. a laser beam) the corona can be excited locally. A 0.0035 inch diameter wire 10 has been positioned approximately 0.050 inches from a bare grounded electrode 12. The voltage on wire 10 is set at 2.5 KV which is below the threshold for corona onset. At these settings, no measurable corona is detected. A laser tuned to a wavelength of 514.5 nm (green) is focused to a 50 micro-meter diameter spot 14 at a location between wire 10 and bare plate 12.

With a laser output of 50 milliwatts, the measured positive ion current 16 is
2.8 micro-amps. With no laser power there is no measurable current. The laser light can be switched on or off and the current follows the on/off pattern of the laser. Since no corona exists without the laser light,...