Note: Descriptions are shown in the official language in which they were submitted.
1 L~
The invention ~elates -to a window pane or door pane
having a darkening device. It is known to ;E:i-t a motor-driven
roller-blind be-tween the shee-ts of an insulating pane constituting
a window or door filling, and to darken the window by means of
this roller-blind.
I-t is also known to associa-te with a window, or a door,
louvres or a Venetian blind as a darkening device.
The production and operation of these known darkening
devices is a matter of relatively great mechanical complexity.
It is the purpose of -the invention to design a darkening
device for a window or door in such a manner -that it will operate
without wear and with a small amount of electrical power.
According to the invention, one way of achieving this
purpose is to use, as the darkening device, a cell extending over
the entire pane, or over a part thereof, the said cell comprising
transparent electrode layers which are spaced from one another.
An electrical voltage may ~e applied to these electrode layers.
A solid or liquid electrolyte containing ions is provided between
the layers. At least one oE the said electrode layers is equipped,
on the side facing the elec-trolyte, with an electrochrOmecoating.
According to a particular aspect, there is provided
a window or door having an insulating glass comprising at least
two glass panes spaced apart from one another and having a darken-
ing device, characterized in -that the darkening device is in the
form of a cell arranged in the interior of the insulating glass,
and extending over all or part of one pane which forms the carrier
therefor, said cell comprising transparent electrode layers which
are spaced apart from one another, and to Which an electr1cal
voltage can be applied, a solicl electrolyte conta:Lrliny ions beiny
provided be-tween said el.ectrode layersand a-t least one e:Lectrocle
ayer being provided wlth an elec-trochromelayer on the side facing
the elec-trolyte.
This electrochromecoating may be applied to the
electrode layer by evapora-tion in a vacuum, by pyrolysis, or by
chemical precipitation, and may be between 0.5 and 1.5 ~m :i.n
thickness. For the purpose of ob-taining an electrochrome reaction
in the electrochromecoating, a voltage of about 2 volts is
preferred.
When the electrical voltage is applied to the electrode,.
layers, the ions migrate out of the electrolyte into the electro--
cnromecoating, which then becomes coloured. The intensity of the
colouring may be controlled by the composition of the electrolyte
and by the length of time during which the elec-
- la -
trical voltage is switchecl on.
The cell used as the darkening device is a static system, the service
life of which is substantially longer than that oE known mechanical designs; and
the small amount of electrical power required to actuate the device may be taken
from one or more batteries.
The total amount of energy passing through the pane in the ultra-
violet, visible and infra-red range of solar and global radiation may be
regulated by the design according to the invention.
Another way of achieving the objects o~ the invention is to use, as
the darkening device, a cell extending over ~he entire pane, or over a part
thereof, which is sealed hermetically at its edges, which is filled with liquid
crystals, which has inner surfaces carrying electrode-layers to which an elec-
trical voltage may be applied, which comprises transparent cover-sheets or
cover-foils arranged in parallel with each other, and which is equipped, at
least on one side, with a polarizing layer.
The range of operating temperatures of the liquid crystals is the meso-
phase range in which the liquid crystals acquire specific crystalline proper-
ties.
Depending upon the structure of the polarizing layer and the selected
state of the liquid crystals, darkening of the window or door pane may be
achieved, in accordance with the invention, either by applying an electrical
voltage to the electrode-layers, or by switching the said voltage off.
If darkening is achieved by applying the electrical voltage to the
electrode-layers, the degree of darkening may be varied smoothly by altering the
voltage.
If the polarizing layer is tuned to the infra-red range, radiation of
infra-red light is eliminated, thus providing thermal insulation and preventing
heat Erom being radlated out oE the room.
Several embodiments oE the cell according to the :invention, used as
the darkening device, will now be described in conjunction with the accompa-ny-
ing drawings. In these drawings:-
Figure 1 is a cross-section of a cell used as a darkening device
located in the interior of an insulating pane;
Figure 2 shows on an enlarged scale, a cell associated with one sheet
of glass;
Figure 3 is a partial view, in cross-section, of a cell, the cover-
sheets of which are sheets of glass;
Figure 4 is a cross-section of a cell defined by transparent cover-
foils; and
Figure 5 shows a cell which, on the one side, has a sheet of glass
as the cover-sheet, and, on the other side, a transparent cover-foil.
In the embodiment shown in Figure 1, sheets 1 and 2 of glass are unit-
ed at the edge-areas to form an insulating pane. Cell 4, constituting the
darkening device, is arranged in the interior 3 thereof and extends over the
entire surface thereof.
The cell ~ comprises a transparent electrode-layer 5 secured to the
inside of glass sheet 1 and provided with an electrochrome coating 6. Associ-
ated with the coating 6 is an electrolyte 7 which contains ions. The electro-
lyte may be in solid or liquid form.
The electrochrome layer 6 may consist of tungsten oxide ~W03), moly-
bdenum oxide (MoO3), niobium oxide (Nb205), vanadium oxide (V205), iridium oxide
(Irox(OH)n x)' rhodium oxide (RhO2), or calcium fluoride (CaF2).
Arranged on the side of the electrolyte remote from the electrochrome
coating is a transparent electrode-layer 8 which may also be in the form of a
grid-system. TE a liquid electrolyte is used,cell ~ would includc a shoet 9 of
glass in relation to interior 3 of the insulating pane.
The interior oE the insulating pane not occupied by cell ~ (indicated
by reference numeral 10) constitutes an air insulation interspace.
The electrochrome reaction in the electrochrome coating, namely the
colouring of the coating by incorporation of the ions in the electrolyte~ is
reversed by elimination of the electrical voltage, so that the ions migrate back
into the electrolyte and the electrochrome coating becomes transparent again.
I-E the electrode-layer comprises individual, electrically conductive
grids which are separate from each other, these may be switched on and off in-
dividually. The grid pattern makes it possible to darken parts of the pane,
as required by incident rays of sunlight, or to darken parts of the pane in
stages by applying less current.
In the embodiment shown in Figure 2, a cell 4 is associated with sheet
1 of glass. This cell comprises electrode-layers 5 and 8, each of which carries
an electrochrome coating 6. Arranged between coatings 6 is a solid electrolyte
7. The total thickness of the cell is between ~ and 5 ~m.
The cell shown in Figure 3 is equipped with two sheets 11 and 12 of
glass arranged parallel with, and at a distance from, each other. Sheets 11 and
12 are connected together at their edges. The inner surfaces of the sheets of
glass carry electrode-layers 13 to which an electrical voltage may be applied
through electrical connections 1~. Electrode layers 13, which may be trans-
parent, evaporated metal coatings, define an inner chamber 15 of the cell.
Chamber 15 is filled with a layer of liquid crystals, the thickness of this
layer being between 10 and 100 ~m.
The cell is equipped with a polarizing layer at least on one side,
e.g. on the outside of glass sheet 11 or 12. This polarizing layer is not shown
L46
in the drawing.
In the embodlment oE ~igure 4, the ce'LI ls cleEined by transpareJIt
cover-foils 1~ and 17 welded together at the;r edge-areas. The inner surfaces
of these foils carry transparent electrode-layers lS which may 'be in the form
of evaporated metal coatings. In order to determine the distance between the
electrode-layers defining inner chamber 19 for the accommodation of liquid
crystals, a transparent grid 20, made of a synthetic material or glass, is
arranged in the said inner chamber. This grid ensures uniform spacing between
the electrode-layers over the entire area of the said inner chc~mber, so that the
thickness of the layer of liquid crystals also does not vary in different areas
of the chamber. This ensures that a uniform darkening effect is achieved over
the entire area of the window pane or door pane and that, when the electrical
voltage is applied to the electrode-layers, uniform deflection, alignment, or
transpositioning of the liquid crystals is produced.
In the arrangement of Figure 5, one side of inner chamber 21 of the
cell is defined by a glass sheet 22, and the other side by a transparent cover-
foil 23. The distance between the sheet of glass and the cover-foil is deter-
mined by small spacers 24 which may be spherical, and may be made of glass or of
a synthetic material. Spacers 24 may also be elongated and made of glass
fibers. The said spacer-elements may be secured to the sheet of glass or to the
cover-foil by welding or by friction. These methods of securing the spacer-
elements are also possible when sheets of glass are used as cover-sheets on both
sides of the cell.
If a window or a door, the frame of which is to contain an insulating
pane, is equipped with a darkening device according to the invention, it is
possible to use parts of the said insulating pane to form the cell. If the
insulating pane consists of two panes of glass, one of them may be used as the
cover-sheets Eor the cell. In this case an air lnterspace must remain between
the second glass cover-sheet of the insulating pane and the other cover-sheet
cover-foil of the cell.
IE the insulating pane consists of three sheets of glass, two of them
may be used as cover-sheets for the cell.
In the embodiment shown in Figure 5, only the cover-sheet, the cover-
Eoil and the spacer elements are shown. Again, in this embodiment, an electrode
layer is provided on the inner surfaces of glass sheet 22 and of cover-foil 23,
and an electrical voltage may be applied to the said electrode-layer. One side
of the cell is also equipped with a polari~ing layer.
