Optical switching device

• US 6,310,725 B1
• Filed: 11/13/2000
• Issued: 10/30/2001
• Est. Priority Date: 09/17/1998
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Duine, Peter Alexander, Van Der Sluis, Paul
• Primary Examiner(s): Phan, James
• Application Number:
  US09/710,831
• Time in Patent Office: 351 Days
• Field of Search: 385/16, 385/18, 359/577, 359/584, 359/585
• US Class Current: 359/585
• CPC Class Codes: G02F 1/19 based on variable-reflection or variable-refraction elements not provided for in groups G02F1/015 - G02F1/169
• CPC Class Codes: G02F 2202/34 Metal hydrides materials

Abstract

A description is given of a switching device (1) comprising a transparent substrate (3) and a switching film (5) which incldes a hydride of a trivalent metal, such as gadolinium, and which is covered with a palladium layer (7). Between the substrate (3) and the switching film (5) a thin magnesium layer (4) is interposed. By exchange of hydrogen, the switching film can be reversibly switched from a transparent state to a highly reflective state. The conversion between both states is reversible, and this phenomenon can be used, for example, in a luminaire or for climate control.

Claims

1. An optical switching device comprising a substrate and a switching film which comprises a hydride of a trivalent metal, which hydride can be reversibly switched between a low-hydrogen, mirror-like composition and a high-hydrogen transparent composition by an exchange of hydrogen, characterized in that a thin magnesium layer is arranged between the substrate and the switching film.

2. A device as claimed in claim 1, characterized in that the thickness of the magnesium layer is between 0.1 and 25 nm, preferably between 0.1 and 10 nm.

3. A device as claimed in claim 1, characterized in that the trivalent metal is selected from the group consisting of gadolinium, erbium, samarium, lutetium, yttrium and lanthanum.

4. A device as claimed in claim 1, characterized in that the switching film is provided with a catalytically active layer comprising at least one metal selected from the group consisting of palladium, platinum, cobalt and nickel.

5. A device as claimed in claim 1, characterized in that the switching film has a thickness in the range from 20 to 1,000 nm.

6. A device as claimed in claim 1, characterized in that the switching film comprises a hydride of an alloy of the trivalent metal and 5 to 95 at. % magnesium.

7. A use of a switching device as claimed in claim 1 as a display or a mirror with variable transmission, or in a luminaire, vision control glass, architectural glass or sunroof.