Browse Prior Art Database

Optical Keyboard

IP.com Disclosure Number: IPCOM000088660D
Original Publication Date: 1977-Jul-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Matino, H: AUTHOR

Abstract

A code plate 1 is attached to the bottom of the individual key 2 in a keyboard for vertical movement with the associated key when depressed. Codes on the code plate 1 are serially sensed by a photocell during vertical travel caused by key depression.

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Optical Keyboard

A code plate 1 is attached to the bottom of the individual key 2 in a keyboard for vertical movement with the associated key when depressed. Codes on the code plate 1 are serially sensed by a photocell during vertical travel caused by key depression.

Code plate 1 may be coded with any known coding, such as a bar code which consists of a series of alternating stripes of contrasting light transmittancy with each stripe representing a binary value depending on the width thereof. Each code plate 1 is supported for movement into a path which is intercepted by a light beam from light source 3. When key 2 is depressed, coded stripes on code plate 1 are serially intercepted by the light beam so as to modulate the beam according to the code on code plate 1. The beam thus modulated is received by a photocell 4, the output of which is used to encode the key depressed in any conventional manner, such as that found in the well-known magnetic card reader. The output of the photocell may be used for encoding in either the downward or upward travel of code plate 1, or in both directions for verification in which the data encoded in upward travel is used to verify in downward travel. Any known mechanism may be used to achieve a uniform velocity of code plate movement in either direction.

Fig. 2 shows how the light beam is transmitted through all code plates on the keyboard from a single light source 3 to a single photocell 4. A mirror 5 is located at the end of e...