Browse Prior Art Database

El Diode Scan

IP.com Disclosure Number: IPCOM000092460D
Original Publication Date: 1966-Nov-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Shah, BR: AUTHOR

Abstract

The device has electroluminescent screen 2 that produces a point of light wherever it is excited by an electric field. This electric field is produced by crystal 3 that is positioned to have one face adjacent to screen 2. The latter incorporates a suitable electrode. Crystal 3 has a second electrode 4. An electrical signal is applied to the electrodes to cause crystal 3 to oscillate. Crystal 3 is wedge-shaped so that for each point on the face of screen 2 there is a unique spacing between the two electrodes. The frequency of crystal 3 varies with the spacing between its electrodes. A particular frequency causes crystal 3 to oscillate in a particular region. The electrical field, associated with the oscillation of crystal 3, produces a spot of light on screen 2.

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El Diode Scan

The device has electroluminescent screen 2 that produces a point of light wherever it is excited by an electric field. This electric field is produced by crystal 3 that is positioned to have one face adjacent to screen 2. The latter incorporates a suitable electrode. Crystal 3 has a second electrode 4. An electrical signal is applied to the electrodes to cause crystal 3 to oscillate. Crystal 3 is wedge-shaped so that for each point on the face of screen 2 there is a unique spacing between the two electrodes. The frequency of crystal 3 varies with the spacing between its electrodes. A particular frequency causes crystal 3 to oscillate in a particular region. The electrical field, associated with the oscillation of crystal 3, produces a spot of light on screen 2. Thus, when the signal applied to crystal 3 is swept through a range of frequencies, a light spot is made to sweep screen 2 in a scanning pattern.

Crystal 3 is connected to be excited by a suitable variable frequency oscillator such as a multivibrator. The output of the multivibrator is a frequency staircase. The height of the staircase represents a particular frequency and a particular point on screen 2.

The horizontal portions of the staircase represent a time interval during which the spot is held at a particular point. The vertical parts of the staircase represent jumps in frequency and corresponding jumps from one point to another on screen 2.

A suitable signal for representing a display...