Variable focal length lenses which have an arbitrarily shaped periphery

• US 5,668,620 A
• Filed: 04/12/1994
• Issued: 09/16/1997
• Est. Priority Date: 04/12/1994
• Status: Expired due to Term

• Current Assignee: Superfocus Holdings LLC
• Original Assignee: Lane Research
• Inventors: Kurtin, Stephen, Epstein, Saul, Fedele, Daniel E.
• Primary Examiner(s): DANG, HUNG XUAN
• Application Number:
  US08/226,344
• Time in Patent Office: 1,253 Days
• Field of Search: 359/666, 359/665, 359/832, 359/722, 359/672, 351/41, 351/158
• US Class Current: 351/158
• CPC Class Codes: G02B 3/14 of variable focal length
• CPC Class Codes: G02C 7/085 Fluid-filled lenses, e.g. electro-wetting lenses

Abstract

A variable focal length lens whose peripheral shape can be arbitrarily specified, for use in spectacles, which includes a rigid lens to provide the wearer'"'"'s distance correction, and a liquid-filled lens bounded by a stretched distensible elastomeric membrane to provide a variable near addition. The liquid, which has a fixed volume, is stored in the field of view between the elastomeric membrane and the rigid lens. Variation of the optical power of the liquid filled lens is achieved by displacement of a membrane support to which the outer periphery of the stretched elastomeric membrane is attached. The shape of the distended membrane is kept substantially spherical, despite the circumference of the membrane being non-circular, by making the free area of the membrane circular. This is accomplished by supporting the membrane on a transparent spacing member which has substantially the same refractive index as the liquid and which includes a circular opening which defines the free area of the membrane. A pair of spectacles is comprised of two variable focal length lenses mounted to a frame with an actuator for adjusting their focal lengths mounted on the frame between the lenses. The actuator is mechanically coupled to the lenses by point contacts which prevent twisting couples from being created in the lens structures.

Claims

1. A variable focal length lens which comprises:

a rigid lens;

a membrane support member positioned across the field of view of said rigid lens and spaced therefrom, said membrane support member having a central portion including support means which supports a transparent distensible membrane whereby said membrane has a substantially circular free area, wherein said support means is in the form of a raised ridge projecting outward from a surface of said membrane support member, said membrane being positioned against said support means and being maintained at all times in contact with said support means in the region of said support means adjacent to said free area of said membrane;

a transparent liquid filling the space between said rigid lens and said membrane;

flexible sealing means for retaining said transparent liquid between said rigid lens and said membrane; and

variable spacing means acting between said rigid lens and said membrane support member for adjusting the spacing between said membrane support member and said rigid lens.

2. A variable focal length lens which comprises:

a rigid lens;

a membrane support member positioned across the field of view of said rigid lens and spaced therefrom, said membrane support member having a central portion including support means which supports a transparent distensible membrane whereby said membrane has a substantially circular free area, wherein said support means is comprised of the area surrounding a substantially circular opening in a surface of said membrane support member and said membrane is not attached to the area of said membrane support member which comprises said support means, said membrane being positioned against said support means and being maintained at all times in contact with said support means in the region of said support means adjacent to said free area of said membrane;

a transparent liquid filling the space between said rigid lens and said membrane;

flexible sealing means for retaining said transparent liquid between said rigid lens and said membrane; and

variable spacing means acting between said rigid lens and said membrane support member for adjusting the spacing between said membrane support member and said rigid lens.

3. A variable focal length lens as recited in claim 2 wherein said surface of said membrane support member is convexly shaped.

4. A variable focal length lens which comprises:

a rigid lens;

a membrane support member positioned across the field of view of said rigid lens and spaced therefrom, said membrane support member having a central portion including support means which supports a transparent distensible membrane whereby said membrane has a substantially circular free area, where said central portion of said membrane support is transparent and has substantially the same refractive index as said transparent liquid, said membrane being positioned against said support means and being maintained at all times in contact with said support means in the region of said support means adjacent to said free area of said membrane;

a transparent liquid filling the space between said rigid lens and said membrane;

flexible sealing means for retaining said transparent liquid between said rigid lens and said membrane; and

variable spacing means acting between said rigid lens and said membrane support member for adjusting the spacing between said membrane support member and said rigid lens, said membrane support member and said rigid lens being hingedly connected, and said variable spacing means acting between said membrane support and said rigid lens remote from said hinge.

5. A variable focal length lens which comprises:

a rigid lens;

a membrane support member positioned across the field of view of said rigid lens and spaced therefrom, said membrane support member having a central portion including support means which supports a transparent distensible membrane whereby said membrane has a substantially circular free area, wherein said support means is in the form of a raised ridge projecting outward from a surface of said membrane support member, said membrane being positioned against said support means and being maintained at all times in contact with said support means in the region of said support means adjacent to said free area of said membrane;

a transparent liquid filling the space between said rigid lens and said membrane;

flexible sealing means for retaining said transparent liquid between said rigid lens and said membrane; and

variable spacing means acting between said rigid lens and said membrane support member for adjusting the spacing between said membrane support member and said rigid lens, said membrane support member and said rigid lens being hingedly connected, and said variable spacing means acting between said membrane support and said rigid lens remote from said hinge.

6. A variable focal length lens as recited in claim 5 where said central portion of said membrane support is transparent and has substantially the same refractive index as said transparent liquid.

7. A variable focal length lens which comprises:

a rigid lens;

a membrane support member positioned across the field of view of said rigid lens and spaced therefrom, said membrane support member having a central portion including support means which supports a transparent distensible membrane whereby said membrane has a substantially circular free area, wherein said support means is comprised of the area surrounding a substantially circular opening in a surface of said support member and said membrane is not attached to the area of said membrane support member which comprises said support means, said membrane being positioned against said support means and being maintained at all times in contact with said support means in the region of said support means adjacent to said free area of said membrane;

a transparent liquid filling the space between said rigid lens said membrane;

flexible sealing means for retaining said transparent liquid between said rigid lens and said membrane; and

variable spacing means acting between said rigid lens and said membrane support member for adjusting the spacing between said membrane support member and said rigid lens, said membrane support member and said rigid lens being hingedly connected, and said variable spacing means acting between said membrane support and said rigid lens remote from said hinge.

8. A variable focal length lens as recited in claim 7 wherein said surface of said membrane support member is convexly shaped.

9. A variable focal length lens as recited in claim 8 where said central portion of said membrane support is transparent and has substantially the same refractive index as said transparent liquid.