LC matrix display with measuring net

In a LC matrix display with an internal reflector and an internal measuring reticle metal electrodes made of chromium, nickel, aluminum or some other metal are used as the internal reflector. By a special configuration of electrodes it is achieved that the measuring reticle is formed in the LC layer itself as a consequence of the optical effects in the liquid crystal. By building in an internal reflector and an internal measuring reticle any parallax is removed when observing the signal curve as well as the measuring reticle and, additionally, a maximum viewing angle is assured.

BACKGROUND 
The invention belongs to the field of liquid crystal (LC) matrix displays. 
In known LC matrix display embodiments external coordinate axes and a 
measuring net are used, which substantially reduces the viewing angle of 
such a display and at measuring there appears a parallax. 
A known embodiment of the LC matrix display with the external coordinate 
axes and the measuring net 6' is shown in FIG. 1, where there are 
represented an upper cover glass plate 1' of the display, orientation 
deposit layers 2', 4', a LC layer 3' with dichroic admixtures, a lower 
glass plate 5' of the LC cell, transparent indium-tin oxide (ITO) 
electrodes a', b', c', d', and reflecting lower electrodes e', which 
represent an internal reflector. 
A considerable parallax error can appear even at a limited viewing angle 
.phi.. This is evident from FIG. 1 showing the prior art LC matrix display 
embodiment although it is not drawn according to scale. The LC layer 3', 
is a hundred times thinner than the glass plate 1' and the dimensions of 
the electrodes a', b', c', d', e' are also substantially smaller than the 
dimension of the glass plate 1'. 
The technical problem resides in producing a LC matrix display, wherein 
there is removed any parallax when observing the displayed signal curve 
and the measuring net, even at a considerable viewing angle. 
SUMMARY OF THE INVENTION 
The technical problem is solved by the present invention with a special 
configuration of electrodes such that the coordinate axes and the 
measuring net are formed in the LC layer itself and as a consequence of 
the electro-optical effects in the liquid crystal. 
The advantage of the subject of the invention over prior art lies in that 
the coordinate axes and the measuring net, formed in the LC layer, and as 
a consequence of the electro-optical effects because of a special 
configuration of the electrodes, contribute to the complete removal of the 
parallax at measuring even at the largest achievable viewing angle.

DETAILED DESCRIPTION 
FIG. 2 shows a cross section of the LC matrix display according to the 
invention. There is shown the upper glass plate 1 of the display, the 
orientation deposit layers 2, 4, the LC layer 3 with dichroic admixtures, 
the lower glass plate 5 of the LC display, the transparent ITO upper 
electrodes a, b, c and the reflecting lower electrode e. The lower 
electrodes are nontransparent chromium, nickel, aluminum or other metal 
electrodes reflecting the light and represent an internal reflector. 
The principle of forming the marked coordinate axes and the measuring net 
by a suitable configuration of interspaces between the electrodes is 
clearly seen in FIGS. 3 and 4. A set U of the transparent upper electrodes 
is built up on the upper glass plate 1 and a set L of the reflecting lower 
electrodes is built up on the lower glass plate 5. All electrodes are 
imbedded in the orientation deposit layer 2,4. 
The electrodes (darker regions of FIGS. 3 and 4), mutually parallel in each 
set U and L, are substantially in the form of strips 6, 16. Electrodeless 
fields 9,19, however, in the upper as well as in the lower electrode set 
are formed by a recess of electrode margins that face each other in the 
middle portion of some electrode strips. 
In general, interspaces 7,17 (ligher regions of FIGS. 3 and 4) between the 
strips 6, 16 are made so narrow that they are hardly visible. The 
electrodeless fields 9, 19 are formed by the electrode margins that face 
each other along some of said narrow interspaces 7, 17. Said fields 9, 19 
are regularly spaced. The interspaces 8, 18, however, which are situated 
on lines X, Y, N (FIG. 5), are enlarged to such an extent that along them 
there appear distinctly the coordinate axes X, Y and other lines N of the 
measuring net. 
The matrix display shown in FIG. 5 is formed when the glass plates 1, 5 are 
assembled, with the electrodes of one set oriented nonparallelly with 
respect to the electrodes of the other set. In a detail D a suitable 
configuration of the interspaces between the electrodes is shown wherein 
the narrow interspaces 7, 17 result in lines N' that are actually too 
narrow to be visible. The enlarged interspaces 8, 18 as well as fields 9, 
19, however, when a nonzero potential difference between the electrode set 
U and the electrode set L is applied, appear on the matrix display as dark 
lines X, Y representing the coordinate axes, which are crossed by short 
marker lines M, and the lines N enclosing bright measuring net fields F. 
Matrix boxes B that are enclosed between the lines N' represent the actual 
measuring points. Each measuring net field F preferably contains a number 
of matrix boxes B. 
Time dependent signals, e.g. binary signals, under the normal static 
control of the LC matrix display are applied to each matrix box B via 
appropriate electrodes and a potential difference arises across the LC 
layer 3 (display activation). A zero potential difference at the chosen 
matrix box B exists when two equal electric signals are applied to the 
related upper and ldwer electrode. These chosen matrix boxes B of zero 
potential difference appear dark on the display. For the same 
electro-optical effect, all LC regions at the interspaces between the 
electrodes also appear dark. 
Since matrix elements having a zero potential difference are visible due to 
their darkness and since for the same electro-optical effects, all 
interspaces between the electrodes also appear dark, FIG. 5 shows the 
strong dark lines of the measuring net and of the coordinate axes with 
shorter marking lines therefor. In FIG. 5 all other lines (N') 
representing the corresponding interspaces between the electrodes are too 
narrow to be visible. The marked coordinate axes and measuring net shown 
in FIG. 5 are actually formed within the LC layer 3 itself as a 
consequence of electro-optical effects. The potential difference across 
boxes B is different from zero unless some box B represents a measuring 
point. The measuring points also appear within the LC layer 3. 
By the specific design of the LC matrix display it is achieved that the 
measuring net and the marked coordinate axes are formed in the LC layer 
itself, which completely eliminates any parallax of the measuring net when 
looking obliquely at a displayed measuring point, even at the largest 
achievable viewing angles; this is represented in FIG. 2. By the fact that 
the thickness of the LC layer 3 is practically about 50 times smaller than 
the width of the electrodes it is evident that the viewing angle is 
practically unlimited. This represents another advantage of the LC matrix 
display according to the invention.