MULTILAYERED LIGHT POLARIZER

• US 3,610,729 A
• Filed: 06/18/1969
• Issued: 10/05/1971
• Est. Priority Date: 06/18/1969
• Status: Expired due to Term

• Current Assignee: Howard G. Rogers
• Original Assignee: Howard G. Rogers
• Inventors: Rogers, Howard G.
• Primary Examiner(s): Schonberg, David
• Assistant Examiner(s): Miller, Paul R.
• Application Number:
  US04/834,339
• Time in Patent Office: 839 Days
• Field of Search: 350/147,152,155,157,166
• US Class Current: 359/485.03
• CPC Class Codes: G02B 5/305 including organic materials, e.g. polymeric layers
• CPC Class Codes: G02F 1/133545 Dielectric stack polarisers

Abstract

This disclosure is directed to a highly efficient linear polarizer which is effective to separate normally incident light thereon into two oppositely polarized components, one of which is transmitted and another component which is reflected.

Claims

1. A highly efficient multilayered reflective-transmissive linear polarizer comprising a plurality of layers on a planar surface of a transparent substrate, said layers being of an optical thickness of one-quarter the wavelength of a selected wavelength of light and each successive layer being alternately composed of a birefringent material and a material having an index of refraction substantially matching one of the two indices of refraction of the birefringent material.

2. A highly efficient multilayered reflective-tranSmissive linear polarizer comprising a plurality of layers on a planar surface of a transparent substrate, said layers being of an optical thickness of one-quarter the wavelength of a selected wavelength of light and each successive layer being alternately composed of a birefringent material and an isotropic material with the index of refraction of said isotropic material substantially matching one of the two indices of refraction of the birefringent material.

3. A highly efficient multilayered reflective-transmissive linear polarizer comprising a plurality of layers on a planar surface of a transparent substrate, said layers being of an optical thickness of one-quarter the wavelength of a selected wavelength of light and each successive layer being alternately composed of a birefringent material and an isotropic material with the index of refraction of said isotropic material substantially matching one of the two indices of refraction of the birefringent material, and said layers of birefringent material having optic axes lying in a plane substantially parallel to said planar surface of said transparent substrate.

4. The polarizer of claim 3 wherein said birefringent layers are composed of a mixture of terephthalic acid and isophthalic acid.

5. A highly efficient multilayered reflective-transmissive linear polarizer for receiving unpolarized light and transmitting and reflecting a large portion of said light in the form of polarized light rays comprising layer means including a plurality of interfaces between said layer means, said interfaces being substantially nonrefractive of a first portion of said light rays having a given vibration azimuth but reflecting a predetermined amount of a second portion thereof having a vibration azimuth orthogonally disposed relative to that of said first portion, said interfaces being bounded on one side by a birefringent layer having one index of refraction substantially equal to an index of refraction of a layer at the opposite side thereof and a second index of refraction differing thererfrom, said layers on either side of said interfaces each having an optical thickness of one-quarter the wavelength of a selected wavelength of light incident on said polarizer.

6. A highly efficient multilayered reflective-transmissive linear polarizer comprising a plurality of layers on a planar surface of a transparent substrate, said layers being of an optical thickness of one-quarter the wavelength of a selected wavelength of light and each successive layer being alternately composed of two different birefringent materials, the materials being such that the lower of the two indices of refraction of one of the materials substantially matches the higher of the two indices of refraction of the other material.

7. A highly efficient multilayered reflective-transmissive linear polarizer comprising a plurality of layers on a planar surface of a transparent substrate, said layers being of an optical thickness of one-quarter the wavelength of a selected wavelength of light and each successive layer being alternately composed of two different birefringent materials, the materials being such that the lower of the two indices of refraction of one of the materials substantially matches the higher of the two indices of refraction of the other material, and said layers of birefringent material having optic axes lying in a plane substantially parallel to said planar surface of said transparent substrate.

8. A highly efficient multilayered reflective-transmissive linear polarizer comprising:

a plurality of layers of selected materials arranged in an interlaminar array to define a corresponding plurality of interfaces;

said materials within alternate said layers having different polarization characteristics causing said interfaces to permit the transmission, substantially unattenuated, of one polarization component of light normally incident thereon and to reflect, at least in part, the orthogonal polarization component of said incident liGht.

9. The linear polarizer of claim 8 wherein any said layer has an optical thickness equal to a whole number multiple (including one) of one-quarter wavelength of said light incident thereupon.

10. The linear polarizer of claim 8 wherein alternate said layers of said selected materials are birefringent.

11. The linear polarizer of claim 8 in which:

alternate said layers of said selected materials are positively birefringent; and

the layers of said selected materials intermediate said alternate layers are negatively birefringent.

12. The linear polarizer of claim 8 wherein said materials forming alternate said layers are birefringent and said materials forming layers intermediate said alternate birefringent layers are isotropic.

13. A highly efficient multilayer reflective-transmissive linear polarizer for receiving normally incident light and transmitting one polarization component and reflecting the orthogonal polarization component thereof, comprising:

a plurality of layers of selected materials arranged in an interlaminar array to define interfaces between adjacent said layers, said interfaces having a greater refractive index discontinuity for a first polarization component of said light than for the orthogonal polarization component thereof, whereby the amount of light reflected at each said interface is greater for said first polarization component of light than for said orthogonal polarization component.

14. The polarizer of claim 13 wherein the thicknesses of said layers are selected such that reflections of said first polarization component of said incident light are caused to constructively interfere.

15. A polarizer as in claim 14 wherein a first of said layer materials is birefringent and a second of said layer materials has a refractive index which substantially matches one of the refractive indices of said birefringent material, said materials being in alternating superposed order to form a plurality of said interfaces.

16. A polarizer as in claim 15 wherein said first material is positively birefringent and said second material is negatively birefringent.

17. A polarizer as in claim 15 wherein said birefringent material is selected from the group consisting of:

polystyrene;

polyethylene terephthalate;

polysulfone;

polycarbonate; and

poly(paraxylylene).

18. A highly efficient multilayer reflective-transmissive linear polarizer for receiving normally incident light and transmitting one polarization component and reflecting the orthogonal polarization component thereof, comprising:

a plurality of layers, each having an optical thickness of one-quarter wavelength of a reflected wavelength of light, the materials of said layers alternating between birefringent polystyrene and polymethyl-methacrylate to form interfaces, each said interface having a polymethyl-methacrylate layer on one side and a birefringent polystyrene layer on the opposite side.