Optical display system having a Brewster's angle regulating film

• US 5,999,314 A
• Filed: 11/19/1997
• Issued: 12/07/1999
• Est. Priority Date: 11/20/1996
• Status: Expired due to Fees

• Current Assignee: Central Glass Company Limited
• Original Assignee: Central Glass Company Limited
• Inventors: Nishikawa, Shinji, Kobayashi, Kazuya, Asakura, Motoh
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Juba, Jr., John
• Application Number:
  US08/974,150
• Time in Patent Office: 748 Days
• Field of Search: 345/7, 359/13, 359/630, 359/487
• US Class Current: 359/485.02
• CPC Class Codes: B32B 17/10036 comprising two outer glass sheets
• CPC Class Codes: B32B 17/10458 Polarization selective transmission
• CPC Class Codes: B32B 17/10761 containing vinyl acetal
• 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 5/30 Polarising elements light-modulating devices with active elements G02F1/00
• CPC Class Codes: G02B 5/3066 involving the reflection of light at a particular angle of incidence, e.g. Brewster's angle

Abstract

A head-up display system of an automotive vehicle, comprising outboard-side and inboard-side glass plates constituting a front windshield glass. An intermediate film is disposed between the outboard-side and inboard-side glass plates to bond the glass plates. A polarization-direction changing layer is secured to the inboard surface of the outboard-side glass plate. A Brewster'"'"'s angle regulating film is secured to the inboard surface of the inboard-side glass plate. The Brewster'"'"'s angle regulating film has a refractive index different from that of the glass plates. A displaying device is provided to generate a display light of information. Additionally, a light-polarizing device is provided to polarize the display light into S-wave. The display light having S-wave is incident at about Brewster'"'"'s angle of the Brewster'"'"'s angle regulating film to the front windshield glass so as to pass through the polarization-direction changing layer and to be reflected at the outboard surface of the outboard-side glass plate toward the side of the displaying device.

Claims

1. A display system comprising:

a displaying device for generating a display light of information;

a light-polarizing device for polarizing the display light;

at least one transparent plate having a refractive index and a corresponding Brewster'"'"'s angle when interfaced with air;

a Brewster'"'"'s angle regulating film secured to a surface of said transparent plate, said Brewster'"'"'s angle regulating film having a refractive index different from that of said transparent plate and having a Brewster'"'"'s angle in air, said Brewster'"'"'s angle regulating film being itself transparent whereby substantially all display light incident thereon passes through said Brewster'"'"'s angle regulating film, preventing said display light from being reflected by said Brewster'"'"'s angle regulating film;

wherein the polarized display light is incident on said Brewster'"'"'s angle regulating film at an angle around Brewster'"'"'s angle of said Brewster'"'"'s angle regulating film, travels through said Brewster'"'"'s angle regulating film to said transparent plate and is reflected toward a side of said displaying device;

wherein said displaying device is locatable to provide display light to said transparent plate at an angle exceeding Brewster'"'"'s angle of said transparent plate corresponding to an interface with air.

2. A display system as claimed in claim 1, wherein said Brewster'"'"'s angle regulating film is formed of a material selected from the group consisting of TiO₂, MgF₂, CaF₂, SiO₂, NaAlO₃, CeO₂, In₂ O₃, and ZnS.

3. A display system as claimed in claim 1, further comprising a polarization-direction changing layer adapted to change a direction of polarization of said display light, said polarization-direction changing layer being formed of a liquid crystal high polymer which is in twisted nematic orientation under a liquid crystal condition and is in a glassy state at a temperature lower than liquid crystal transition point thereof.

4. A display system according to claim 3 wherein said Brewster'"'"'s angle regulating film is formed of a material selected from the group consisting of TiO₂, MgF₂, CaF₂, SiO₂, NaAlO₃, CeO₂, In₂ O₃, and ZnS.

5. A display system comprising:

a displaying device for generating a display light of information;

a light-polarizing device for polarizing the display light into P-wave;

at least one transparent plate having a refractive index and a corresponding Brewster'"'"'s angle when interfaced with air;

a polarization-direction changing layer secured to a first surface of said transparent plate;

a Brewster'"'"'s angle regulating film secured to a second surface of said transparent plate, said Brewster'"'"'s angle regulating film having a refractive index different from that of said transparent plate and having a Brewster'"'"'s angle in air, said Brewster'"'"'s angle regulating film being itself transparent, whereby substantially all display light incident thereon passes through said Brewster'"'"'s angle regulating film, preventing said light from being reflected by said Brewster'"'"'s angle regulating film;

wherein the display light having P-wave is incident on said Brewster'"'"'s angle regulating film at an angle around Brewster'"'"'s angle of said Brewster'"'"'s angle regulating film and travels through said Brewster'"'"'s angle regulating film to said transparent plate to pass through said polarization-direction changing layer and to be reflected toward a side of said displaying device;

wherein said displaying device is locatable to provide display light to said transparent plate at an angle exceeding Brewster'"'"'s angle of said transparent plate corresponding to an interface with air.

6. A display system as claimed in claim 5, further comprising a light-transmittable reflection film secured to the first surface of said transparent plate, the display light having S-wave being reflected by said light-transmittable reflection film to be directed toward the side of said displaying device.

7. A display system as claimed in claim 5, wherein said at least one transparent plate includes first and second transparent plates, said first transparent plate being located outside relative to said second transparent plate defining a space in which a person resides,

wherein said display system further comprises an intermediate film disposed between said first and second transparent plates to bond said first and second transparent plates, and

wherein said polarization-direction changing layer is bonded to said first transparent plate and separate from said second transparent plate so that a layer of said intermediate film lies between said first polarization-direction changing layer and said second transparent plate.

8. A display system according to claim 5, wherein said Brewster'"'"'s angle regulating film is formed of a material selected from the group consisting of TiO₂, MgF₂, CaF₂, SiO₂, NaAlO₃, CeO₂, In₂ O₃, and ZnS.

9. A display system comprising:

a displaying device for generating a display light of information;

a light-polarizing device for polarizing the display light into S-wave;

at least one transparent plate having a refractive index and a corresponding Brewster'"'"'s angle when interfaced with air;

a polarization-direction changing layer secured to a first surface of said transparent plate;

a Brewster'"'"'s angle regulating film secured to a second surface of said transparent plate, said Brewster'"'"'s angle regulating film having a refractive index different from that of said transparent plate and having a Brewster'"'"'s angle in air, said Brewster'"'"'s angle regulating film being itself transparent, whereby substantially all display light incident thereon passes through said Brewster'"'"'s angle regulating film, preventing said light from being reflected by said Brewster'"'"'s angle regulating film;

wherein the display light having S-wave is incident on said Brewster'"'"'s angle separating film at an angle around Brewster'"'"'s angle of said Brewster'"'"'s angle regulating film and travels through said Brewster'"'"'s angle regulating film to said transparent plate to pass through said polarization-direction changing layer and to be reflected toward a side of said displaying device;

wherein said displaying device is locatable to provide display light to said transparent plate at an angle exceeding Brewster'"'"'s angle of said transparent plate corresponding to an interface with air.

10. A display system as claimed in claim 9, further comprising a light-transmittable reflection film secured to the first surface of said transparent plate, the display light having P-wave being reflected by said light-transmittable reflection film to be directed toward the side of said displaying device.

11. A display system as claimed in claim 9, wherein said at least one transparent plate includes first and second transparent plates, said first transparent plate being located outside relative to said second transparent plate defining a space in which a person resides,

wherein said display system further comprises an intermediate film disposed between said first and second transparent plates to bond said first and second transparent plates, and

wherein said polarization-direction changing layer is bonded to said first transparent plate and separate from said second transparent plate so that a layer of said intermediate film lies between said first polarization-direction changing layer and said second transparent plate.

12. A display system according to claim 9, wherein said Brewster'"'"'s angle regulating film is formed of a material selected from the group consisting of TiO₂, MgF₂, CaF₂, SiO₂, NaAlO₃, CeO₂, In₂ O₃, and ZnS.

13. A display system comprising:

a displaying device for generating a display light of information;

a light-polarization device for polarizing the display light into P-wave;

at least one transparent plate having a refractive index and a corresponding Brewster'"'"'s angle when interfaced with air;

a Brewster'"'"'s angle regulating film formed at a first surface of said transparent plate, said Brewster'"'"'s angle regulating film having a refractive index different from that of said transparent plate and having a Brewster'"'"'s angle in air, said Brewster'"'"'s angle regulating film being itself transparent, whereby substantially all display light incident thereon passes through said Brewster'"'"'s angle regulating film, preventing said light from being reflected by said Brewster'"'"'s angle regulating film;

a polarization-direction changing layer secured to a first surface of said transparent plate;

wherein the display light having P-wave is incident on said Brewster'"'"'s angle regulating film at an angle around Brewster'"'"'s angle of said Brewster'"'"'s angle regulating film and travels through said Brewster'"'"'s angle regulating film to said transparent plate to pass through said polarization-direction changing layer, and to be reflected toward a side of said displaying device;

wherein said displaying device is locatable to provide display light to said transparent plate at an angle exceeding Brewster'"'"'s angle of said transparent plate corresponding to an interface with air.

14. A display system as claimed in claim 13, wherein said at least one transparent plate is a single transparent plate having the first surface defining a space where a person resides.

15. A display system as claimed in claim 14, further comprising a light-transmittable reflection film secured to a second surface of said transparent plate which second surface is opposite to the first surface, the display light having P-wave being reflected by said light-transmittable reflection film to be directed toward the side of said displaying device.

16. A display system according to claim 13, wherein said Brewster'"'"'s angle regulating film is formed of a material selected from the group consisting of TiO₂, MgF₂, CaF₂, SiO₂, NaAlO₃, CeO₂, In₂ O₃, and ZnS.