Anti-reflective transparent coating with gradient zone

• US 5,234,748 A
• Filed: 06/19/1991
• Issued: 08/10/1993
• Est. Priority Date: 06/19/1991
• Status: Expired due to Fees

• Current Assignee: Ford Motor Company
• Original Assignee: Ford Motor Company
• Inventors: Demiryont, Hulya, Surowiec, Roman
• Primary Examiner(s): Turner, A. A.
• Application Number:
  US07/717,606
• Time in Patent Office: 783 Days
• Field of Search: 428/446, 428/428, 428/698, 428/216, 428/212, 428/426, 428/701, 428/702, 428/913, 430/57, 430/63
• US Class Current: 428/216
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: C03C 17/3435 comprising a nitride, oxynitride, boronitride or carbonitride
• CPC Class Codes: C03C 17/3482 comprising silicon, hydrogenated silicon or a silicide
• CPC Class Codes: C03C 2217/732 made of a single layer
• CPC Class Codes: C03C 2217/91 Coatings containing at least one layer having a composition gradient through its thickness
• CPC Class Codes: G02B 1/115 Multilayers
• CPC Class Codes: Y10S 428/913 Material designed to be responsive to temperature, light, moisture
• CPC Class Codes: Y10T 428/24942 including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/24975 No layer or component greater than 5 mils thick

Abstract

An anti-reflective coating employing a gradient layer of Si_1-x Q_x O_y wherein Q is H, for which x has a value from zero to 0.5, or N, for which x has a value from zero to 0.58, and the value of y varies with depth in the coating, increasing from zero closest the substrate to 2. In certain preferred embodiments the anti-reflective coating is substantially transparent to visible light and yet provides good anti-reflectance. Laminated glazing units having such anti-reflective coatings can be used, for example, in applications requiring high transmittance of visible light, such as motor vehicle windshields.

Claims

1. An article comprising a substrate having a surface and an anti-reflective layer on the surface of the substrate, the anti-reflective layer comprising a first zone of Si_1-x Q_x, a gradient zone of Si_1-x Q_x O_y over the first zone wherein y has a value increasing with distance from the surface of the substrate from zero to 2, and a third zone of SiO₂ over the gradient zone, Q and x being independently selected for the first and gradient zones, Q being selected from H, for which the value of x is from zero to 0.5, and N, for which the value of x is from zero to 0.58, wherein the first zone is 1 to 8 nm thick, the value of y increases substantially continuously in the gradient zone and the gradient zone is 3 to 160 nm thick, and the third zone is 30 to 500 nm thick.

2. The article of claim 1 further comprising a reverse gradient zone of Si_1-x Q_x O_z mediate the substrate and the first zone, Q and x being as defined in claim 1 and z having a value which decreases from a first value at an interface with the substrate surface to zero at an interface with the first zone.

3. The article of claim 2 wherein said first value of z is from about 1.8 to 2.0.

4. The article of claim 1 wherein the value of x in the gradient zone decreases with distance from the substrate surface from an initial value to about zero.

5. The article of claim 1 wherein the value of y in the gradient zone increases substantially continuously with distance from the substrate.

6. The article of claim 1 wherein the substrate is substantially transparent.

7. The article of claim 6 wherein the substrate is soda-lime glass.

8. The article of claim 1 wherein Q is H and x has a value between 0.05 and 0.2 in the first zone.

9. The article of claim 1 wherein Q is N and x has a value between zero and 0.58 in the gradient zone.

10. The article of claim 1 wherein the value of x varies with distance from the substrate in at least one of said zones.

11. The article of claim 1 wherein x is zero in said first and gradient the zones of the anti-reflective layer.

12. The article of claim 1 wherein x is zero in the first and third zones, and x is between zero and 0.58 and Q is N in the gradient zone.