Glass pane with reflectance reducing coating and combiner of head-up display system

• US 5,496,621 A
• Filed: 04/15/1994
• Issued: 03/05/1996
• Est. Priority Date: 04/16/1993
• Status: Expired due to Fees

• Current Assignee: Central Glass Company Limited
• Original Assignee: Central Glass Company Limited
• Inventors: Makita, Kensuke, Takamatsu, Atsushi, Tanaka, Katsuto
• Primary Examiner(s): Ryan, Patrick J.
• Assistant Examiner(s): Krynski, William A.
• Application Number:
  US08/228,522
• Time in Patent Office: 690 Days
• Field of Search: 428/600, 428/195, 428/212, 428/210, 428/688, 428/216, 428/336, 428/436, 428/679, 428/701, 428/702, 428/439, 428/432, 428/437, 428/913, 359/359, 359/586, 359/589
• 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: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/012 comprising devices for attenuating parasitic image effects
• CPC Class Codes: G02B 2027/0194 with combiner of laminated type, for optical or mechanical aspects
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 5/286 having four or fewer layers, e.g. for achieving a colour effect
• 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
• CPC Class Codes: Y10T 428/265 1 mil or less
• CPC Class Codes: Y10T 428/3163 Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.]

Abstract

The invention relates to a transparent coating on a transparent glass pane which may be a laminated glass pane such as an automobile windshield. The present invention provides a two-layer coating including a first layer which is a transparent oxide film in direct contact with the major surface of the glass substrate and a second layer which is a transparent oxide film. The first layer has a thickness of 70-230 nm and a refractive index of 1.80-2.10 and includes a major portion and a minor portion which is exposed and adapted to be used as a combiner of a head-up display system. The second layer is formed on the major portion of the first layer so as to expose the minor portion of the first layer. The second layer has a thickness of 110-130 nm and a refractive index of 1.40-1.50. An additional film is optionally formed on the minor portion of the first layer so as to fully or partly cover the minor portion. The additional layer is adapted to be used as a wavelength-selective combiner of the head-up display system. The two-layer coating except the minor portion is adapted to be used as a reflectance reducing coating. To reduce the reflectance of perpendicularly incident light the two-layer coating can be modified into a three-layer coating by interposing another oxide film.

Claims

1. A coated glass pane, comprising a transparent glass substrate and a fluoride-free coating formed on a major surface of the glass substrate, the fluoride-free coating comprising:

a first layer which is a transparent oxide film in direct contact with the major surface of the glass substrate and has a thickness of 70-230 nm and a refractive index in the range from 1.80 to 2.10, said first layer having a major portion and a minor portion which is exposed and adapted to be used as a combiner of a head-up display system; and

a second layer which is a transparent oxide film formed on the major portion of said first layer so as to expose the minor portion of said first layer, said second layer having a thickness of 110-130 nm and a refractive index in the range from 1.40 to 1.50, said second layer together with the major portion of said first layer being adapted to be used as a reflectance reducing coating.

2. A coated glass pane according to claim 1, wherein said first and second layers are constructed such that, with respect to visible light incident on said second layer from the coated side of the coated glass pane at an incidence angle in the range from 50 to 70 degrees, the reflectance of the coated glass pane is lower than the reflectance of the glass substrate without coating by 4.5 to 6.5%.

3. A coated glass pane according to claim 1, wherein said first layer is a mixed oxide film comprising at least one relatively high refractivity oxide selected from the group consisting of TiO₂ and ZrO₂ and at least one relatively low refractivity oxide selected from the group consisting of SiO₂, Al₂ O₃ and B₂ O₃.

4. A coated glass pane according to claim 3, wherein said first layer is a binary oxide film formed of TiO₂ and SiO₂.

5. A coated glass pane according to claim 3, wherein said first layer is a binary oxide film formed of ZrO₂ and SiO₂.

6. A coated glass pane according to claim 3, wherein said first layer is a binary oxide film formed of TiO₂ and A1₂ O₃.

7. A coated glass pane according to claim 1, wherein said second layer is a SiO₂ film.

8. A coated glass pane, comprising a transparent glass substrate and a fluoride-free coating formed on a major surface of the glass substrate, the fluoride-free coating comprising:

a first layer which is a transparent oxide film in direct contact with the major surface of the glass substrate and has a thickness of 70-100 nm and a refractive index in the range from 1.80 to 1.95, said first layer having a major portion and a minor portion which is exposed and adapted to be used as a combiner of a head-up display system;

a second layer which is a transparent oxide film formed on the major portion of said first layer so as to expose the minor portion of said first layer, said second layer having a thickness of 130-165 nm and a refractive index in the range from 2.10 to 2.30; and

a third layer which is a transparent oxide film formed on said second layer so as to expose the minor portion of said first layer, said third layer having a thickness of 110-130 nm and a refractive index in the range from 1.40 to 1.50, said third layer together with said second layer and the major portion of said first layer being adapted to be used as a reflectance reducing coating.

9. A coated glass pane according to claim 8, wherein said first layer is a mixed oxide film comprising at least one relatively high refractivity oxide selected from the group consisting of TiO₂ and ZrO₂ and at least one relatively low refractivity oxide selected from the group consisting of SiO₂, Al₂ O₃ and B₂ O₃.

10. A coated glass pane according to claim 9, wherein said first layer is a binary oxide film formed of TiO₂ and SiO₂.

11. A coated glass pane according to claim 8, wherein said third layer is a SiO₂ film.

12. A coated glass pane according to claim 8, wherein said second layer is a film comprising at least one member selected from the group consisting of TiO₂, Ta₂ O₅, and a combination of at least one member selected from the group consisting of TiO₂ and Ta₂ O₅ and at least one member selected from the group consisting of SiO₂, ZrO₂, Al₂ O₃ and B₂ O₃.

13. A coated glass pane, comprising a transparent glass substrate and a fluoride-free coating formed on a major surface of the glass substrate, the fluoride-free coating comprising:

a first layer which is a transparent oxide film in direct contact with the major surface of the glass substrate and has a thickness of 70-230 nm and a refractive index in the range from 1.80 to 2.10, said first layer having minor and major portions;

a second layer which is a transparent oxide film formed on the major portion of said first layer and has a thickness of 110-130 nm and a refractive index in the range from 1.40 to 1.50, said second layer together with the major portion of said first layer being adapted to be used as a reflectance reducing coating; and

an additional film which is a transparent oxide film formed on the minor portion of said first layer so as to fully or partly cover the minor portion of said first layer, said additional film having a thickness of 50-200 nm and a refractive index in the range from 2.50 to 2.50 and being adapted to be used as a wavelength-selective combiner of a head-up display system.

14. A coated glass pane according to claim 13, wherein said additional film is a film comprising at least one member selected from the group consisting of TiO₂ and a combination of TiO₂ and at least one member selected from the group consisting of SiO₂ and ZrO₂.

15. A coated glass pane, comprising a transparent glass substrate and a fluoride-free coating formed on a major surface of the glass substrate, the fluoride-free coating comprising:

a first layer which is a transparent oxide film in direct contact with the major surface of the glass substrate and has a thickness of 70-100 nm and a refractive index in the range from 1.80 to 1.95, said first layer having minor and major portions;

a second layer which is a transparent oxide film formed on the major portion of said first layer and has a thickness of 130-165 nm and a refractive index in the range from 2.10 to 2.30;

a third layer which is a transparent oxide film formed on s said second layer and has a thickness of 110-130 nm and a refractive index in the range from 1.40 to 1.50; and

an additional film which is a transparent oxide film formed on the minor portion of said first layer so as to fully or partly cover the minor portion of said first layer, said additional film having a thickness of 50-200 nm and a refractive index in the range from 2.00 to 2.50 and being adapted to be used as a wavelength-selective combiner of a head-up display system.