Method and apparatus for making polarized sunglasses

• US 9,128,302 B2
• Filed: 10/28/2013
• Issued: 09/08/2015
• Est. Priority Date: 10/28/2013
• Status: Expired due to Fees

• Current Assignee: Distributed Polarization Inc.
• Original Assignee: Distributed Polarization Inc.
• Inventors: Trapani, Giorgio, Tendler, Robert K.
• Primary Examiner(s): Dang, Huang
• Application Number:
  US13/998,388
• Publication Number:
  US 20150116658A1
• Time in Patent Office: 680 Days
• Field of Search: 351/49, 351/45, 351/46, 351/44, 351/41, 351/163, 351/165, 351/159, 359/485, 359/490, 359/501
• US Class Current: 1/1
• CPC Class Codes: G02C 7/12 Polarisers

Abstract

In the manufacture of gradient polarized sunglasses an optical retarder is used in front of a portion of a polarized lens to destroy the linear polarization of incoming light to render that portion of the sunglass lens non-polarized, thus to permit viewing of polarized displays through that non-polarized portion of the polarized sunglass lens.

Claims

1. A method for fabricating sunglasses having a polarized region and an un-polarized region comprising the steps of:

providing polarized sunglass lenses; and

,

overlying the front portion of the polarized lenses with an optical retarder whereby polarized light impinging on the optical retarder is depolarized providing an un-polarized portion of the sunglass lens.

2. The method of claim 1, wherein the optical retarder includes a sheet of transparent material having a quarter wavelength thickness.

3. The method of claim 1, wherein the optical retarder includes a transparent sheet having phase retardation equal to several full wavelengths.

4. The method of claim 1, wherein the optical retarder includes a top edge and wherein the boundary between the top edge of the optical retarder and the underlying polarized lens is visible.

5. The method of claim 1, wherein the sunglass lens includes a polarized layer sandwiched between transparent covers and wherein the optical retarder is interposed between the polarized layer and a top cover, the sandwiched elements being adhered together with an adhesive having a refractive index which matches the refractive indices of the polarized layer and the transparent covers.

6. The method of claim 5, wherein the transparent covers are made of glass.

7. The method of claim 6, wherein the adhesive is taken from the group consisting of a thermal epoxy optical adhesive.

8. The method of claim 6, wherein the adhesive is an UV cured optical adhesive.

9. The method of claim 1, wherein the optical retarder comprises a sheet of clear plastic material, the clear plastic material having a machine direction parallel to the polarizing direction of the polarized lens and wherein the bottom portion of the clear plastic sheet is stretched so as to produce a quarter wave thickness at 45 degrees to the polarization direction of the polarized lens.

10. The method of claim 9, wherein the clear plastic sheet is stretched in a direction 45 degrees to the machine direction.

11. The method of claim 1, wherein the optical retarder includes a clear plastic sheet having a portion thereof stretched in a direction 45 degrees with respect to the machine direction of the clear plastic sheet to provide an optical thickness in the stretched portion equivalent to a quarter wave retardation.

12. The method of claim 11, wherein the demarcation between the stretched portion of the clear plastic sheet and the unstretched portion is invisible.