DICHROMIC MIRROR HAVING MULTILAYER THIN FILMS INCLUDING VANADIUM DIOXIDE

• US 3,834,793 A
• Filed: 06/21/1973
• Issued: 09/10/1974
• Est. Priority Date: 06/21/1973
• Status: Expired due to Term

• Current Assignee: John R. Trimmier, Lloyd T. Mcconnell
• Original Assignee: John R. Trimmier, Lloyd T. Mcconnell
• Inventors: McConnell, Lloyd T., Trimmier, John R.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Godwin, Paul K.
• Application Number:
  US05/372,378
• Time in Patent Office: 446 Days
• Field of Search: 350/16R,288,290
• US Class Current: 359/289
• CPC Class Codes: G02B 5/201 in the form of arrays
• CPC Class Codes: G02B 5/23 Photochromic filters
• CPC Class Codes: G02B 5/286 having four or fewer layers, e.g. for achieving a colour effect

Abstract

An optical effect device in the form of a multi-layer mirror, with at least one layer consisting of vanadium dioxide, and the layers being limited in thickness to about 2,000 Angstroms such that interference effects can provide essentially any desired color. Methods are disclosed for determining what two colors are achievable with a given mirror as the VO2 is carried through its transition temperature, and methods are disclosed for optimizing the contrast in reflectance between the mirror in its hot and cold states.

Claims

2. The temperature-dependent mirror as claimed in claim 1 and further including a thin, transparent dielectric film on top of the coating of vanadium dioxide.

3. The temperature-dependent mirror as claimed in claim 2 wherein the index of refraction of the dielectric film is appreciably different from the index of refraction of vanadium dioxide.

4. The temperature-dependent mirror as claimed in claim 2 wherein the dielectric film is selected from the group including silicon dioxide magnesium flouride, and aluminum oxide.

5. The temperature-dependent mirror as claimed in claim 1 wherein a transparent dielectric material is interposed between the vanadium dioxide and the substrate, and said dielectric material has a lower thermal conductivity than the vanadium dioxide, whereby the resolution of a recorded image in the vanadium dioxide in response to thermal stimuli will be enhanced.

6. The temperature-dependent mirror as claimed in claim 1 and further including a second thin layer of vanadium dioxide, with the layers of vanadium dioxide being separated from each other by a transparent layer of a dielectric material.

7. The temperature-dependent mirror as claimed in claim 6 wherein each of the vanadium dioxide films has a thickness in the range of about 150A to 2,000A.