Memory and display device uses cathodochromic material to store visual information and fast phosphor to recall information for display and electronic processing. Cathodochromic material changes color when bombarded with electrons, and is restored to its original color when exposed to light of appropiate wavelength

Bosomworth, D. R.

Moles, W. H.

English

NASA Technical Reports Server

Optics 
and 
Photo 
Detector 
Cathodochromic 
Powder Layer Layer 
Deftec
October 1972	 B72-10647 
NASA TECH BRIEF 
Goddard Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
A Visual-Display and Storage Device 
The problem: 
Most display systems do not have an intrinsic memory 
capability; data must usually be stored in a buffer 
memory which continually refreshes the display. This 
arrangement is inefficient and expensive. 
The solution: 
A memory and display (MAD) device has been made 
which uses a cathodochromic material to store visual 
information and a fast phosphor to recall the informa-
tion for display and electronic processing. 
How it's done: 
A cathodochromic material is one which will undergo 
a color change when it is bombarded with electrons; it is
restored to its original color when exposed to light of 
the appropiate wavelength. The cathodochromic material 
used in this MAD is sodalite:Cl, an aluminosilicate with 
the composition Na 8 A1 6 Si 6024 C1 2 . The display unit is 
depicted in the figure. The cathode ray tube electron 
beam is modulated by a video signal as it scans a normal 
TV raster. A highly visible color image with an induced 
optical density proportional to the electron beam 
intensity is stored in the sodalite layer. 
The sensitive, phosphor layer is used to recover the 
stored image in the form of a reconstituted electronic 
video signal. A constant current electron beam scans the 
phosphor layer at an energy low enough to keep the 
electrons from reaching the sodalite layer. The phosphor 
then emits a uniform radiation. The materials are 
Display and Storage Device
(continued overleaf) 
This document was prepared under the sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19720000646 2020-03-17T03:41:31+00:00Z
chosen so that the colored portion of the sodalite 
layer absorbs radiation at the wavelength of the phosphor 
emission. In this way, the signal picked up by the 
external photodetector is directly related to the original 
video signal. 
The MAD uses a 115-V, 60-Hz power line fused 
for 20A. A useful image can be stored in 1/30 second 
and kept for up to twenty-four hours. The image has 
500 TV line resolution, and the contrast ratio is 
nearly 2:1. 
The system can be modified to meet the requirements 
of a wide range of applications. It can be used to 
store and display computer generated data; if further 
processing is desirable, the data can be read and returned 
to the computer. In receiving telemetry signals, data may 
be stored in a single TV frame to be later regenerated 
and transmitted to other locations. The MAD could 
also be used in computer design, coherent optical 
processing, and many other applications.
Note: 
Requests for further information may be directed to 
Technology Utilization Officer 
Goddard Space Flight Center 
Code 207.1 
Greenbelt, Maryland 20771 
Reference: B72-10647 
Patent status: 
NASA has decided not to apply for a patent. 
Source: D.R. Bosomworth and W.H. Moles of
RCA Corp.
under contract to
Goddard Space Flight Center 
(GSC-10901) 
B72-10647	 Category 02


A visual-display and storage device

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