Illuminating system for endoscope or borescope

• US 4,733,937 A
• Filed: 10/17/1986
• Issued: 03/29/1988
• Est. Priority Date: 10/17/1986
• Status: Expired due to Term

• Current Assignee: GE Inspection Technologies LP (General Electric Company)
• Original Assignee: Welch Allyn Incorporated
• Inventors: Anderegg, Jane, Lia, Raymond A.
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/920,159
• Time in Patent Office: 529 Days
• Field of Search: 350/96.18, 350/96.20, 350/96.24, 350/96.25, 350/96.26, 350/432, 128/6
• US Class Current: 385/117
• CPC Class Codes: A61B 1/00096 Optical elements
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: G02B 23/2469 using optical fibres

Abstract

An optical illuminating system for endoscope or borescope has a round fiber optic bundle light guide and a non-spherical lens disposed at the distal end of the light guide. The lens has a flat front surface and a compound rear optical surface formed of a central flat circular portion of smaller diameter than the fiber optic bundle light guide, and a frustoconic surface that flares back from the central surface beyond the diameter of the fiber optic light guide. The conic portion of this lens provides an annular distribution of light, and the disc portion provides a spot distribution to fill in the center of the annular distribution. The overall distribution is thus generally flat over an angle of up to 120 degrees.

Claims

1. An optical illuminating lens for use in an endoscope or borescope in which a round fiber optic bundle carries light through the endoscope or borescope to a distal end thereof, the lens having a front surface and a compound rear optical surface formed of a substantially flat central circular surface portion of smaller diameter than said fiber optic bundle defining a central portion of the lens and a flared surface surrounding said central circular surface portion and having a significantly sharper incidence angle, with respect to light from the fiber optic bundle, than said circular surface portion, the flared surface extending back from said circular surface portion out beyond the diameter of said bundle and defining an outer portion of the lens;

the rear surface fitting against said bundle with the lens central portion centered thereof, such that the outer portion distributes the light from said bundle as a ring of light and said central portion distributes said light as a spot to fill in the center of said ring, thus creating an overall generally flat distribution.

2. An optical illuminating lens as recited in claim 1 wherein said flared surface portion is frustoconic.

3. An optical illuminating lens as recited in claim 1 wherein said front surface is substantially flat.

4. An optical illuminating lens as recited in claim 1 wherein a space is defined between said fiber optic bundle and the rear optical surface of said lens, and said space is filled with a medium of smaller refractive index than said fiber optic bundle or said lens.

5. An optical illuminating lens as recited in claim 1 in which the lens is formed of pressed glass.

6. An illuminating optical arrangement for an endoscope or borescope which comprises an optical fiber bundle light guide which consists of a multiplicity of optical fibers bound together in parallel in a generally cylindrical bundle and which terminates at a distal end thereof with polished ends disposed in a single plane;

and a frustoconic distributing lens having a proximal surface facing the distal end of said optical fiber bundle light guide, said distributing lens including outer means aligned with an outer portion of the distal end of the light guide for distributing the light therefrom as a ring of light, and central means aligned with a central portion of the distal end of said light guide for distributing the light therefrom as a disc of light to fill the center of said ring of light, thus to create a substantially even distribution of illumination.

7. The illuminating optical arrangement of claim 6 in which said outer means includes a concave frustoconic lens portion and said central means includes a substantially flat lens portion.

8. The illuminating optical arrangement of claim 6 in which said frustoconic distributing lens is a single lens having a substantially flat distal surface and a compound proximal surface, said proximal surface including a central flat disc of lesser diameter than said fiber optic bundle light guide and with the front surface defining said central means, and a frustoconic surface flaring proximally outward from the edge of said central disc and with the front surface defining said outer means.

9. The illuminating optical arrangement of claim 6 in which said even distribution of light attains over a cone of illumination of at least substantially one hundred twenty degrees.

10. An optical illuminating lens for use in an endoscope or borescope in which a round fiber optic bundle carries light through the endoscope or borescope to a distal end thereof, the lens having a substantially flat front surface and a compound rear optical surface formed of a central circular surface portion of smaller diameter than said fiber optic bundle defining a central portion of the lens and a flared surface surrounding said central circular surface portion and having a significantly sharper incidence angle, with respect to light from the fiber optic bundle, than said circular surface portion, the flared surface extending back from said circular surface portion out beyond the diameter of said bundle and defining an outer portion of the lens;

the rear surface fitting against said bundle with the lens central portion centered thereon, such that the outer portion distributes the light from said bundle as a ring of light and said central portion distributes said light as a spot to fill in the center of said ring, thus creating an overall generally flat distribution.