Artifact Details

Title

Focusing Light Pen

Catalog Number

X406.84

Type

Physical object

Date

ca. 1963

Manufacturer

Massachusetts Institute of Technology (MIT) Electronic Systems Laboratory

Place Manufactured

U.S.

Identifying Numbers

Model number #2
Other number ESL-7849CN005 on side of pen.

Dimensions

3/4 x 6 1/4 x 3/4 in.

Description

Engraved text: ESL-7849CN005 MOD #2 Constructed as part of project MAC. The ESL display console was I/O for an IBM 7094. "Automatic Light Pen Tracking. Another important function of a display system is graphical input- and a very useful technique for accomplishing this is light pen tracking. The usual programmed tracking (periodically displaying a tracking pattern- testing light pen response- and calculating new coordinates- all under program control) typically requires about 10 percent of a computer's time for adequate performance. In order to reduce this drain on computer capacity- the function of the pen tracking has been completely implemented with hardware on the ESL Console." from "Display Hardware for Dynamic Man- Machine Interaction" by John E. Ward June 7-9- 1966. This pen provided improved pen-to-phosphor seperation by including a focus adjustment. The IBM 780 (?) scope- on which the pen was used was not designed with light-pen use in mind. It had a canted faceplate to reduce reflections. The phosphor-faceplate separtation varied between 3/4" to 2"over the screen- and the resulting gain and field-of-view variations of the light-pen were therefore unacceptable.

Category

I/O: pointing: lightpen

Subject

Input; Pointing

Credit

Loan Courtesy of John E. Ward

Lot Number

X406.84