Method for producing an inhomogeneous film for selective reflection/transmission of solar radiation

• US 4,322,276 A
• Filed: 06/20/1979
• Issued: 03/30/1982
• Est. Priority Date: 06/20/1979
• Status: Expired due to Term

• Current Assignee: NV Bekaert SA
• Original Assignee: Deposition Technologies, Inc.
• Inventors: Meckel, Nathan K., Meckel, Benjamin B.
• Primary Examiner(s): Gantz, Delbert E.
• Assistant Examiner(s): LEADER, WILLIAM T
• Application Number:
  US06/050,484
• Time in Patent Office: 1,014 Days
• Field of Search: 204/192 R, 204/192 P, 204/298, 428/472
• US Class Current: 204/192.26
• CPC Class Codes: C03C 17/002 for flat glass, e.g. float glass
• CPC Class Codes: C23C 14/56 Apparatus specially adapted for continuous coating; Arrangements for maintaining the vacuum, e.g. vacuum locks
• CPC Class Codes: F24S 23/82 characterised by the material or the construction of the reflector
• CPC Class Codes: Y02E 10/40 Solar thermal energy, e.g. solar towers

Abstract

A sputtered thin film coating characterized by a stepwise and/or variable refractive index as a function of film depth. By means of an in-line assembly of planar magnetrons, each magnetron essentially isolated from the others but for a region of sputtering overlap, select materials and combinations of said materials with reactive gases can be continuously deposited upon a dynamic substrate whereby to obtain pre-determined refractive index gradients. Substrates coated with an inhomogeneous thin film exhibit superior non-spectral reflective characteristics particularly desirable for architectural designs and applications.

Claims

1. A method for sputtering an inhomogeneous thin film laminate upon a transparent substrate which comprises the steps of:

(a) positioning a substrate upon a holder within a vacuum chamber, said chamber defined by two or more essentially isolated sub-chambers;

(b) adjusting apertures through which said substrate translates into adjacent sub-chambers whereby to form regions of overlap wherein said substrate simultaneously receives sputter deposition from magnetron cathodes contained within adjacent sub-chambers;

(c) positioning at least one magnetron cathode within each of said sub-chambers, said cathodes comprising material to be sputter deposited;

(d) evacuating said chamber to a predetermined low pressure;

(e) flushing said evacuated chamber with non-reactive gas thereby to reduce wall gas impurities contained therein;

(f) back filling each of said sub-chambers to predetermined pressures with non-reactive gas;

(g) further introducing reactive gas into one or more of said sub-chambers whereby predetermined atmospheres are produced within each of said sub-chambers;

(h) differentially pumping said gases through said sub-chambers whereby the predetermined atmospheres within each of said sub-chambers are maintained; and

(i) sequentially translating said substrate at a constant rate of speed through each of said sub-chambers whereby an inhomogeneous coating of cathode material is deposited thereon.

2. The method according to claim 1 wherein said non-reactive gas is argon.

3. The method of claim 1 wherein said reactive gas is oxygen.

4. The method according to claim 1 wherein said substrate comprises a coil of transparent polymeric sheet material.

5. The method according to claim 1 wherein said substrate sequentially translates through predetermined atmospheres which comprise:

(a) a first reactive sputtering region wherein metallic oxide is deposited upon said substrate;

(b) a first overlap region wherein said substrate simultaneously receives sputter deposition from said first reactive region and a first non-reactive sputtering region;

(c) a first non-reactive sputtering region wherein metal is deposited upon said substrate;

(d) a second overlap region wherein said substrate simultaneously receives sputter deposition from said first non-reactive region and a second reactive sputtering region; and

(e) a second reactive sputtering region wherein metallic oxide is deposited upon said substrate.