Electrically controllable device having variable optical qualities or system which is holographic, thermotropic or which has suspended particles
AssigneeSaint-Gobain Glass France
InventorsGregoire Mathey, Jean-Christophe Giron
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Abstract
The subject of the invention is an element having variable optical properties, comprising: (a) a system having electrically controlled variable light scattering, of the optical-valve or liquid-crystal system type, a suspended-particle system or a holographic or thermotropic system (a′) which is associated with (b) at least one absorbent element, absorbing at least in the visible range. It applies especially to the manufacture of backprojection screens.
Claims26
An element having variable optical properties, comprising:
- (a)—a system having electrically controlled variable light scattering, of the optical-valve or liquid-crystal system type, a suspended-particle system or a holographic or thermotropic system (a′) which is associated with
- (b)—at least one absorbent element, absorbing at least in the visible range. chosen from at least one of the following elements:
- bulk-tinted glass or plastic rigid substrate (2), bulk-tinted sheet of flexible polymer of the thermoplastic type, plastic film that can be calendered to a rigid substrate, thin absorbent layer placed on one of the face of a glass or plastic rigid substrate or of a sheet of flexible polymer.
The element as claimed in one of the preceding claims, characterized in that the system (a) is a liquid-crystal system (1) comprising a film of liquid-crystal droplets dispersed in a medium and contained by two protective sheets each provided with an electrode and in that the absorbent element(s) (b) is (are) chosen from at least one of the following elements:
- dye within the film, electrically conducting absorbent layer forming part of one of the electrodes.
The element as claimed in one of the preceding claims, characterized in that the combination of the absorbent elements (b) increases the light absorption AL of the element having optical properties in its entirety by at least 5%, and/or lowers the light reflection RL of the element having optical properties in its entirety by at least 5%, especially by at least 8%.
The element as claimed in one of the preceding claims, characterized in that the absorbent element is bulk-tinted glass (2), having a thickness of 1 to 8 mm, preferably with a color in transmission in the grays.
The element as claimed in one of the preceding claims, characterized in that the absorbent element is a bulk-tinted thermoplastic sheet of the PVB, PU or EVA type, preferably with a color in transmission in the grays.
The element as claimed in one of the preceding claims, characterized in that it also includes:
- (c) at least one element (7, 7′) antireflecting in the visible.
The element as claimed in one of the preceding claims, characterized in that it is a glazing assembly based on 1, 2 or 3 glass substrates (3, 2, 8).
The element as claimed in one of the preceding claims, characterized in that it forms part of a backprojection screen operating in transmission.
Dependencies are inferred from the claim text.