Dual-pane thermal window with liquid crystal shade

• US 5,152,111 A
• Filed: 03/09/1992
• Issued: 10/06/1992
• Est. Priority Date: 06/25/1987
• Status: Expired due to Term

• Current Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Baughman, Ray H., Eckhardt, Helmut, Buff, Ernest D., Fuchs, Gerhard H.
• Primary Examiner(s): CHILCOT, RICHARD E
• Application Number:
  US07/848,472
• Time in Patent Office: 211 Days
• Field of Search: 52/171, 52/172, 52/173 R, 52/788, 52/328, 359/43, 359/52, 359/53, 359/62, 359/63, 359/70-74, 359/82-84, 359/96, 359/98, 428/34
• US Class Current: 52/171.3
• CPC Class Codes: E06B 2009/2464 featuring transparency control by applying voltage, e.g. LCD, electrochromic panels
• CPC Class Codes: E06B 3/6722 with adjustable passage of light
• CPC Class Codes: G02F 1/133308 Support structures for LCD panels, e.g. frames or bezels
• CPC Class Codes: G02F 1/1347 Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells

Abstract

A dual-pane thermal window unit comprises two non-intersecting or, preferably, substantially parallel, spaced window panes, mounted in a window frame, a first of the panes having affixed thereto a first wall of an electro-optical liquid crystal cell providing a selected light transmittance, and a second of said panes delimiting, with a second wall of said cell, a space providing a thermal break. Each of the first and second walls comprises an electrically conductive film composed of plastic and having sufficient supporting strength to maintain the structural integrity of the cell. The window is light weight, economical to manufacture and efficient and reliable in operation.

Claims

1. A method for decreasing radiative and conductive heat transfer between the exterior and the interior of a building, comprising the steps of:

(a) mounting within a window frame a plurality of spaced window panes, a first and a second of said panes having opposing faces;

(b) affixing to one of the opposing faces a first wall of a liquid crystal cell, said first wall being composed of transparent, electrically conductive film and cooperating with a second wall composed of transparent electrically conductive film to form a cavity containing an electro-optically responsive liquid crystal material providing a selected light transmittance, said film being composed of plastic and said first and second walls having sufficient supporting strength to maintain the integrity of said cell;

(c) affixing to said second wall a third wall of a second liquid crystal cell, said third wall being composed of transparent, electrically conductive film and cooperating with a fourth wall of said second liquid crystal cell composed of transparent, electrically conductive film to form a second cavity containing an electro-optically responsive liquid crystal material providing a selected light transmittance, said film being composed of plastic and said third and fourth walls having sufficient supporting strength to maintain the integrity of said cell; and

(d) delimiting between said fourth wall of said second cell and the other of said opposing faces of said panes a space providing a thermal break.

2. A method as recited in claim 1, comprising the step of adjusting said window panes to be substantially parallel.

3. A method as recited in claim 1, comprising the step of sealing said window panes to isolate said space.

4. A method as recited in claim 3, wherein said sealing step includes the step of injecting an inert gas into said space to enhance thermal break characteristics.

5. A method as recited in claim 3 wherein said inert gas is selected from the group consisting of argon, nitrogen, dry air, neon and mixtures thereof.

6. A thermal-pane window with an electro-optical shade for use in a window space of a building structure, comprising:

(a) window frame means for securing the mutual orientation of a plurality of transparent, substantially parallel, sequentially spaced panes and for sealingly isolating a space therebetween;

(b) a first transparent pane mounted in said window frame means in a position toward an exterior facing side of said frame means;

(c) a second transparent pane, substantially parallel to and spaced from said first pane, mounted in said frame means in a position toward an interior facing side of said frame means;

(d) a first liquid crystal cell comprising a first wall composed of transparent, electrically conductive film, a second wall composed of transparent, electrically conductive film and a liquid crystal material disposed between opposing faces of said first and second walls, said liquid crystal material being electro-optically responsive and said first and second walls having sufficient supporting strength to maintain the integrity of said cells;

(e) a second liquid crystal cell comprising a third wall composed of transparent, electrically conductive film, a fourth wall composed of transparent, electrically conductive film and a second liquid crystal material disposed between opposing faces of said third and fourth walls, said liquid crystal material being electro-optically responsive and said third and fourth walls having sufficient supporting strength to maintain the integrity of said cells;

(f) said first wall of said first cell being affixed to one of the opposing faces of said first and second panes, said third wall of said second cell being affixed to said second wall of said first cell and said fourth wall of said second cell delimiting with the other opposing face of said first and second panes a space providing a thermal break; and

(g) electrical means for applying an electric field between said conductive films and through said liquid crystal material of a selected field strength at least sufficient to change the optical transmission of said liquid crystal material.

7. A window unit as recited in claim 6, wherein said liquid crystal material is electro-optically responsive over a full range of transmittance to a low voltage field.

8. A window unit as recited in claim 6, wherein said space has disposed therewith in an inert gas to enhance thermal break characteristics.

9. A window unit as recited in claim 8, wherein said inert gas is selected from the group consisting of argon, nitrogen, dry air, neon and mixtures thereof.

10. A window unit as recited in claim 7, wherein said liquid crystal material is selected from the group consisting of nematic, smectic, cholesteric and mixtures thereof.

11. A window unit as recited in claim 7, wherein said liquid crystal material has intimately mixed therewith monomeric or polymeric dye molecules that are dichoroic and have anisotropic shape sufficient to effect preferential orientation thereof.

12. A window unit as recited in claim 7, wherein at least one of said panes is composed of plastic.

13. A window unit is recited in claim 7, wherein said liquid crystal material is adapted to change opacity in response to integrated current flow.

14. A window unit as recited in claim 7, wherein said liquid crystal material is adapted to change opacity in response to voltage applied as a gradient across at least one of said walls of conductive film.

15. A window unit as recited in claim 14, wherein said voltage gradient is produced by varying the thickness of said film.

16. A window unit as recited in claim 14, wherein said voltage gradient is produced by varying voltage applied to opposing sides or opposing ends of said walls of said first and second cells.