Method and apparatus for generating a structured light beam array

• US 4,523,809 A
• Filed: 08/04/1983
• Issued: 06/18/1985
• Est. Priority Date: 08/04/1983
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Taboada, John, Altschuler, Bruce R.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/520,356
• Time in Patent Office: 684 Days
• Field of Search: 350/170, 350/169, 350/163, 350/166, 356/354, 356/359, 356/376, 356/2
• US Class Current: 359/577
• CPC Class Codes: G02B 27/106 for splitting or combining a plurality of identical beams or images, e.g. image replication
• CPC Class Codes: G02B 27/126 The splitting element being a prism or prismatic array, including systems based on total internal reflection
• CPC Class Codes: G02B 5/00 Optical elements other than lenses light guides G02B6/00; optical logic elements G02F3/00
• CPC Class Codes: G02B 5/001 Axicons, waxicons, reflaxicons
• CPC Class Codes: Y10S 359/90 Methods

Abstract

Apparatus for simultaneously generating a space volume-filling structural light beam array utilizes a prism assembly which refracts a laser light beam so as to partition it into four separate segments. The four segments produced the two-by-two rectangular beam array by coherent interference of the segments.

Claims

1. A method of simultaneouslu generating a space volume-filling structured light beam array for projection upon an object in non-contact surface metrology, comprising the steps of:

(a) generating a coherent light beam;

(b) projecting said beam with slight divergence through a predetermined plane;

(c) partitioning said beam received at said plane into four light beam segments of predetermined spacing and pattern;

(d) generating from said beam segment pattern, a two-dimensional array comprising an interference pattern of said beam segments; and

(e) projecting said array in a direction orthogonal to the plane of the array onto said object.

2. The generating method of claim 1, wherein said partitioning of said beam occurs through refraction thereof into four separate segments.

3. The generating method of claim 2, wherein said partitioning produces a rectangular beam segment pattern.

4. Apparatus for generating a space volume-filling structured light beam array for projection upon an object in non-contact surface metrology comprising:

(a) means for generating a coherent light beam;

(b) means for projecting said beam with slight divergence through a predetermined plane;

(c) means for partitioning said beam received at said plane into four light beam segments of predetermined spacing and pattern;

(d) means for generating from said beam segment pattern, a two dimensional array comprising an interference pattern of said beam segments; and

(e) means for projecting said array onto said object.

5. Generating apparatus as recited in claim 4, wherein said partitioning means comprises means for refracting said beam into four separate segments.

6. Generating apparatus as recited in claim 5, wherein said refracting means comprises a pyramid-shaped prism.

7. Generating apparatus as recited in claim 5, wherein said refracting means comprises a prism assembly composed of two crossed, three-facet prisms arranged in tandem.

8. Generating apparatus as recited in claim 4 wherein:

said generating means comprises a laser, an objective lens and a spatial filter;

said projecting means comprises a recollimating lens located subsequent to said spatial filter;

said partitioning means comprises a prism assembly for refracting said beam into four separate segments and producing thereby a rectangular beam array by coherent interference of said four segments of said beam;

said projecting means comprises a projection lens interposed between said prism assembly and said object.

9. A method of simultaneously generating multiple space volume-filling structured light beam arrays of predetermined wavelengths in any combination, comprising the steps of:

(a) generating coherent light beams of said predetermined wavelengths, including four different wavelengths of light generated as four beams from four sources;

(b) projecting said beams with slight divergence through a predetermined plane;

(c) partitioning each beam received at said plane into four light beam segments of predetermined spacings and patterns;

(d) generating from said beam segment patterns two-dimensional arrays comprising interference patterns of said beam segments; and

(e) projecting said arrays onto an object in which the derived arrays from each wavelength overlap on the object.

10. The generating method of claim 9 wherein said partitioning of said beams occurs through refraction thereof where each beam partitions into four separate segments.

11. The generating method of claim 10 wherein said partitioning produces multiple rectangular beam segment patterns.

12. Apparatus for simultaneously generating multiple space volume-filling light beam arrays of predetermined wavelengths in any combination, comprising;

(a) means for generating coherent light beams of said predetermined wavelengths, including four different wavelengths of light generated as four beams from four sources;

(b) means for projecting said beams with slight divergence through a predetermined plane;

(c) means for partitioning each beam received at said plane into four light beam segments of predetermined spacings and patterns;

(d) means for generating from said beam segment patterns two dimensional arrays comprising interference patterns of said beam segments; and

(e) means for projecting said arrays onto an object in which the derived arrays from each wavelength overlap on the object.

13. Generating apparatus as recited in claim 12, wherein said beam partitioning and array generating means comprise a set of two, orthogonally oriented three-facet prisms having linear edges which intersect with one another at multiple locations, said beams being aligned with said locations and when projected into said locations generating multiple of sets of arrays.

14. Generating apparatus as recited in claim 13, wherein each beam contains multiple wavelengths of light coaxially aligned with an intersecting location of said linear edges of said prisms and when projected into said intersecting location generating multiple sets of arrays for each intersecting location.

15. Generating apparatus as recited in claim 13, wherein said projecting means includes a plurality of lenses of differing focal lengths.