Browse Prior Art Database

Columnator for Card Reader

IP.com Disclosure Number: IPCOM000093014D
Original Publication Date: 1967-Apr-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Graham, JE: AUTHOR

Abstract

The columnator, used in punched card reading, cuts out all light not aimed directly at a photosensitive device. The columnator comprises two thin plates treated with a nonreflective coating, each including a small opening defining an optical axis 1. The columnator also has a thin glass dust cover, a holder which includes a separate light chamber treated with a nonreflective coating, and a photodevice.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 100% of the total text.

Page 1 of 2

Columnator for Card Reader

The columnator, used in punched card reading, cuts out all light not aimed directly at a photosensitive device. The columnator comprises two thin plates treated with a nonreflective coating, each including a small opening defining an optical axis 1. The columnator also has a thin glass dust cover, a holder which includes a separate light chamber treated with a nonreflective coating, and a photodevice.

Ray 2, which is outside the maximum light acceptance angle as defined by rays 3 and 4, strikes the lower plate 9 at a low angle of incidence and is absorbed. Ambient light, as exemplified by ray 5, is eliminated also because the geometry of the arrangement does not allow ambient light to come within the angle of acceptance.

If an opening is not in alignment with the columnator, the card stock diffuses the light. Most of these diffused light rays are outside of the acceptance angle and are therefore absorbed by the component parts of the columnator. By eliminating unwanted rays of light, a high signal-to-noise ratio is obtained.

1

Page 2 of 2

2

[This page contains 2 pictures or other non-text objects]