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Ionized Light Emitter Using Piezoelectric Crystal

IP.com Disclosure Number: IPCOM000075045D
Original Publication Date: 1971-Jul-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 3 page(s) / 54K

Publishing Venue

IBM

Related People

Battison, AH: AUTHOR

Abstract

Ionized patterns associated with a vibrating crystal are used to observe certain crystal patterns, see for example, "A Visual Method For Studying Modes Of Vibration Of Quartz Plates" A. M. Skellett, Journal of the Optical Society of America, Vol. 17, October 1928, pages 308-317. The presently described device utilizes this principle to provide an effective light source.

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Ionized Light Emitter Using Piezoelectric Crystal

Ionized patterns associated with a vibrating crystal are used to observe certain crystal patterns, see for example, "A Visual Method For Studying Modes Of Vibration Of Quartz Plates" A. M. Skellett, Journal of the Optical Society of America, Vol. 17, October 1928, pages 308-317. The presently described device utilizes this principle to provide an effective light source.

The light source is preferably configured as an evacuated demountable structure 10, as shown in Figs. 1, 2. The conductive metal plate or body 11 has an enlarged frontal window aperture 12. A suitable transparent window member 13, such as quartz or glass, is seated and sealed, e.g. with an epoxy, within aperture 12. A smaller concentric and elongated aperture 14 provides a housing in the plate 11.

Mounted in aperture 14 is a metal conductive thin plate member
15. The latter has an enlarged aperture 16. A second metal conductive plate 17 is mounted above member 15. Plate 17 is shown, by way of example, as having a single smaller concentric aperture 18.

On top of plate 17 and over the aperture 18 is a thickness-shear mode cut crystal 19. The crystal 19 may have any suitable geometrical shape. In the example shown, a square piezoelectric crystal is utilized. Members 15 and 17 coact as one of the electrodes for crystal 19. A four corner clamping metal member 20 rests its four legs, e.g. leg 21, atop the respective four corners of crystal 19. Member 20 acts as the other electrode for crystal 19. Alternatively, a mirror image arrangement of elements similar to elements 15 and 17 may be used in lieu of element 20.

A conductive metal pad 22 rests on top of the electrode 20. One end of an insulated wire lead 23 is affixed to pad 22. The other end is connected to the central conductor 24 of coaxial connector 25 which is mounted, sealed and grounded to the body 11. Members 20 and 22 are insulated at their respective sides from the member 11 by suitable means, now shown.

Crystal 19 is of slightly smaller size than the top electrode 20. The shape of the top electrode 20 is compatible to the shape of the crystal being used. An electrically insulated, but heat removing, member 26 is interposed between a mechanical bias spring 27 and 22. The characteristics of spring 27 are selected to provide a predetermined biasing stress to the crystal 19. Alternatively, a means, not shown, for adjusting the spring pressure may be provided, if desired.

The upper end of spring 27 is seated against a bearing plate 28, fastened with screws 28' to the body plate 11. As a result, crystal 19 is aligned in housing
14. The alignment is such that during operation, standing waves generated on the crystal's surface are appropriately registered and will cause the resulting light patterns to emanate from the aperture exits, such as holes 16, 18. An 0-ring gasket 29 is provided between plate 11 and rear plate 30. A groove is provided in at least one of the pl...