€ 
«i 
& 
MATRA OPTIC 
On the back of the screen, in contact with its diffusing 
surface, a glass plate is inserted, on which the floating 
mark is materialized. There are several floating marks on 
the plate. 
This special arrangement allows the operator to select the 
preferred mark for a particular purpose without any mechani- 
cal or optical manipulation, and to switch from one to the 
other with absolute accuracy. The deviation is measured 
when calibrating the instrument and taken into consideration 
automatically by the computer by simple call out on the key- 
board. A reference code on the screen indicates the mark 
selected for use. Special plates with marks of any shape or 
dimensions may be ordered. Each of the photo carrier plates 
may be rotated X 15 degrees to orient images on the screen. 
A system is provided for cooling the emulsion in the illumin- 
ated area when film is used. The projection lens assemblies 
are interchangeable. Three sets are provided to give a choice 
of three enlargements on the screen: 10x magnification with a 
field of view of 45 mm, 18x and 27x magnification with fields 
of view of 30 mm and 16 mm respectively. 
Display and control console: 
The control console is designed with all operating controls 
positioned around the screen. However, there are no direct 
mechanical connections between the two units in order to pro- 
tect the screen image stability from vibrations. The control 
console design satisfies a man/machine interface survey de- 
fining an optimum working position. On the left and right side 
respectively of the projection screen are located: 
- an alpha numeric console permitting dialogue with the com- 
puter and a CRT display of instructions and results for the 
operator, and 
- a television monitor receiving the image of the drawing being 
made via a camera fixed on the moving pencil holder of the 
drawing table. 
Travel is controlled in X and Y by a ball on an air cushion, 
and operated by the right hand. The Z is controlled by a large 
drum-shaped roller, with the left hand. Between these two con- 
trols is an alpha numeric keyboard to provide communication with 
the computer. 
Several function keys are centered under the main screen: 
. point setting 
. exposure l, exposure 2, selector key 
. initializer keys 
. travel speed selector key 
. pen up, pen down key 
For the convenience of the operator some frequently used functions 
are also controlled by foot switches. A foot control switch in- 
verts X and Y parallax during set up, and activates the pen on the