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Optical Shift Register

IP.com Disclosure Number: IPCOM000096114D
Original Publication Date: 1964-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 3 page(s) / 103K

Publishing Venue

IBM

Related People

Lohmann, AW: AUTHOR

Abstract

This device obtains a large shift in the position of a displayed character with a small mechanical movement. Each character is encoded by drawing slightly diagonal lines equally spaced across the character cell as shown in A for the letter L. Vertical lines are drawn through each point of intersection of a diagonal line and the character boundary. An encoded form of the character is then obtained in the form of a mask with vertical stripes of transparent areas as shown in B. Each transparent stripe is bounded by the two vertical lines passing through the two points of intersection of a single diagonal line with the character boundary. Thus, the width of each stripe is proportional to the distance between the two intersecting points.

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Optical Shift Register

This device obtains a large shift in the position of a displayed character with a small mechanical movement. Each character is encoded by drawing slightly diagonal lines equally spaced across the character cell as shown in A for the letter L. Vertical lines are drawn through each point of intersection of a diagonal line and the character boundary. An encoded form of the character is then obtained in the form of a mask with vertical stripes of transparent areas as shown in B. Each transparent stripe is bounded by the two vertical lines passing through the two points of intersection of a single diagonal line with the character boundary. Thus, the width of each stripe is proportional to the distance between the two intersecting points.

A second mask 10 consisting of narrow transparent diagonal slits, corresponding in position and angle to the diagonal lines drawn across the face of the character, is then placed over the encoded form of the character as shown in C. Areas of transparency through the combination of the two masks form an image of the original character as shown in C. A slight horizontal shift of the diagonal slit mask shifts the image vertically as shown in D. A shift equal to the distance between two slits moves the image vertically by one cycle so that the image is once again in its original location.

The device can be used in a correlation reader. In this, multiple images of an unknown character are formed in front of masks corresponding to each character of the font. Light passing through each mask is picked up by a separate photoreceiver. The photoreceiver with the largest output is sensed to identify the unknown character. The device has the advantage that very little mechanical shift horizontally is required to obtain the vertical shift of the mask necessary for exact alignment with the unknown character image.

A second device is shown in E. In this, character 19 is covered with a fixed mask 20 consisting of slightly diagonal transparent slits. Light from the combination is scanned by a single narrow vertical slit 21 moving horizontally. The diagonal slits are slightly tilted, and, as slit 21 scans horizontally, its intersection with a diagonal slit moves along the latter from bottom to top before the vertical slit intersects the bottom of the next diagonal slit. The output of the scanning vertical slit is focused by le...