Laminated glass panel incorporating hologram sheet

• US 5,066,525 A
• Filed: 01/18/1990
• Issued: 11/19/1991
• Est. Priority Date: 01/25/1989
• Status: Expired due to Term

• Current Assignee: Central Glass Company Limited
• Original Assignee: Central Glass Company Limited
• Inventors: Umebayashi, Masanori, Nakamachi, Fumihiko
• Primary Examiner(s): Cashion, Jr., Merrell C.
• Assistant Examiner(s): Nakarani, D. S.
• Application Number:
  US07/466,852
• Time in Patent Office: 670 Days
• Field of Search: 430/1, 430/2, 350/3.7, 350/3.85, 350/174, 156/99, 428/426, 428/437, 428/480, 428/414, 428/474.4, 428/473.5, 428/500, 428/220, 428/29, 428/141
• US Class Current: 428/29
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• CPC Class Codes: B44F 1/02 produced by reflected light, e.g. matt surfaces, lustrous surfaces
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• 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 27/0103 comprising holographic elements
• CPC Class Codes: G03H 1/0252 Laminate comprising a hologram layer
• CPC Class Codes: G03H 2001/186 Swelling or shrinking the holographic record or compensation thereof, e.g. for controlling the reconstructed wavelength G03H2001/0033, G03H2250/44 take precedence
• CPC Class Codes: G03H 2001/2231 Reflection reconstruction
• CPC Class Codes: G03H 2250/37 Enclosing the photosensitive material
• CPC Class Codes: G03H 2250/39 Protective layer
• CPC Class Codes: Y10T 428/24355 Continuous and nonuniform or irregular surface on layer or component [e.g., roofing, etc.]
• CPC Class Codes: Y10T 428/31507 Of polycarbonate
• CPC Class Codes: Y10T 428/3163 Next to acetal of polymerized unsaturated alcohol [e.g., formal butyral, etc.]
• CPC Class Codes: Y10T 428/31721 Of polyimide
• CPC Class Codes: Y10T 428/31725 Of polyamide
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]
• CPC Class Codes: Y10T 428/31855 Of addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31859 Next to an aldehyde or ketone condensation product

Abstract

The invention relates to a laminated glass panel incorporating therein a hologram sheet. For example, the laminated glass panel is a vehicle windshield in which the hologram sheet is used as a combiner of a head-up display. As adhesive means, the laminated glass panel uses either one sheet or two sheets of polyvinyl butyral resin (PVB) film. In the former case the hologram sheet is interposed between the PVB film and one of the glass plate and shielded from the PVB film by a transparent resin or glass film which prevents the plasticizer contained in the PVB film from transferring to the hologram sheet. In the latter case the hologram sheet is interposed between the two sheets of PBB film and shielded from each PVB film by a transparent resin or glass film having the aforementioned property. By virtue of the shielding of the hologram sheet from the PVB film, the diffraction wavelength of the hologram sheet does not significantly shift from the aimed wavelength. To prevent blurring of the holographic images, it is preferable that each transparent film for the shielding purpose has a very smooth surface at least on the side facing the PVB film.

Claims

1. A laminated glass panel, comprising:

two transparent glass plates arranged opposite and parallel to each other;

a polyvinyl butyral resin film which contains a plasticizer and is interposed between the two glass plates as adhesive means;

a hologram sheet interposed between said polyvinyl butyral resin film and one of the two glass plates; and

a transparent film which is tightly interposed between said hologram sheet and said polyvinyl butyral resin film so as to shield said hologram sheet from said polyvinyl butyral resin and prevents said plasticizer from transferring from said polyvinyl butyral resin film to said hologram sheet, wherein the surface roughness of said transparent film is not more than 2 μ

m at least on the side facing said polyvinyl butyral resin film.

2. A laminated glass panel according to claim 1, wherein the material of said transparent film is a synthetic resin.

3. A laminated glass panel according to claim 2, wherein said synthetic resin is selected from the group consisting of polyester resins, polycarbonate resins, acrylic resins, polyethylene resins, polyimide resins, polyamide resins, polyvinyl alcohol resins, polypropylene resins, polybutene resins, polyacrylonitrile resins, polymethylpentene resins and ionomer resins.

4. A laminated glass panel according to claim 1, wherein the material of said transparent film is an inorganic glass.

5. A laminated glass panel according to claim 1, further comprising another polyvinyl butyral resin film which contains a plasticizer and is interposed as supplementary adhesive means between said polyvinyl butyral resin film and said one of the glass plates so as to interpose said hologram sheet between the two polyvinyl butyral resin films, and another transparent film whose surface roughness is not more than 2 μ

m at least on the side facing said another polyvinyl butyral resin film which is tightly interposed between said hologram sheet and said another polyvinyl butyral resin film so as to shield said hologram sheet from said another polyvinyl butyral resin film and prevents the plasticizer in said another polyvinyl butyral resin film from transferring to said hologram sheet.

6. A laminated glass panel according to claim 5, wherein the material of said transparent film and said another transparent film is a synthetic resin.

7. A laminated glass panel according to claim 6, wherein said synthetic resin is selected from the group consisting of polyester resins, polycarbonate resins, acrylic resins, polyethylene resins, polyimide resins, polyamide resins, polyvinyl alcohol resins, polypropylene resins, polybutene resins, polyacrylonitrile resins, polymethylpentene resins and ionomer resins.

8. A laminated glass panel according to claim 5, wherein the material of said transparent film and said another transparent film is an inorgnic glass.

9. A laminated glass panel according to claim 1, wherein said hologram sheet is a reflection hologram sheet.