Optical sensor array mounting and alignment

• US 6,117,193 A
• Filed: 10/20/1999
• Issued: 09/12/2000
• Est. Priority Date: 10/20/1999
• Status: Expired due to Term

• Current Assignee: Amkor Technology Singapore Holding Pte., Ltd. (Amkor Technology Incorporated)
• Original Assignee: Amkor Technology Incorporated
• Inventors: Glenn, Thomas P.
• Primary Examiner(s): Graybill, David E.
• Application Number:
  US09/422,008
• Time in Patent Office: 328 Days
• Field of Search: 29/25.01, 438/16
• US Class Current: 29/25.01
• CPC Class Codes: H01L 2224/32225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48227 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA

Abstract

A method and apparatus for mounting an optical sensor to, and in optical alignment with, a lens or other imaging-forming element of an optical device includes attaching a fixture to the lens, the fixture having mounting features located thereon at predetermined positions measured relative to the focal plane of the lens, the optical axis of the lens, and the horizontal and vertical axes of a scene imaged by the lens. The absolute locations of the plane, the center, and the horizontal and vertical axes of the sensor array are found within and independently of the sensor package using automated optical pattern recognition apparatus. Using numerically controlled apparatus, complementary mounting features are then milled into the sensor package at positions measured relative to the absolute locations of the sensor features found by the pattern recognition equipment that correspond to the predetermined positions of the mounting features on the fixture measured relative to the optical features of the lens.

Claims

1. A method for mounting a packaged optical sensor array to a lens in optical alignment therewith, comprising:

attaching a fixture to the lens, the fixture having mounting features on it located at predetermined positions measured relative to a focal plane of the lens, an optical axis of the lens, and horizontal and vertical axes of a scene imaged by the lens;

finding the absolute locations of a plane, a center, and horizontal and vertical axes of the sensor array within the sensor package; and

,

forming corresponding, complementary mounting features in the package of the sensor array at positions measured relative to the absolute locations found of the plane, the center, and the horizontal and vertical axes of the sensor array, said positions corresponding to said predetermined positions of the mounting features measured relative to the focal plane of the lens, the optical axis of the lens, and the horizontal and vertical axes of the scene imaged by the lens, respectively, such that,

when the mounting features on the fixture are engaged with the corresponding, complementary mounting features in the package of the sensor array, the sensor array is held mounted to the lens, with the plane of the sensor array coplanar with the focal plane of the lens, the center of the sensor array coincident with the optical axis of the lens, and the horizontal and vertical axes of the sensor array aligned with the respective horizontal and vertical axes of the scene imaged by the lens.

2. The method of claim 1, wherein finding the absolute locations of the plane, the center, and the horizontal and vertical axes of the sensor array comprises scanning the sensor array within the sensor package using automated pattern recognition apparatus to find at least one of said locations.

3. The method of claim 2, wherein forming the corresponding, complementary mounting features in the sensor array package comprises milling said mounting features into the package of the sensor array at said measured positions using computer-controlled milling apparatus positioned in accordance with said absolute sensor array feature locations found by said automated pattern recognition apparatus.

4. The method of claim 3, further comprising:

mounting a plurality of projections on the lens at distinct, predetermined polar coordinates measured relative to the optical axis of the lens and the horizontal and vertical axes of a scene imaged by the lens, the projections extending outward from the lens toward the focal plane of the lens and in a direction parallel to the optical axis thereof, each projection having a distal end; and

,

milling a plurality of recesses into the package of the sensor array at polar coordinates measured relative to the center and the horizontal and vertical axes of the sensor array that correspond to said distinct, predetermined polar coordinates of said projections, respectively, the recesses being adapted to receive a corresponding one of the distal ends of the projections in a complementary engagement such that the sensor array is mounted to the lens, with the plane of the sensor array coplanar with the focal plane of the lens, the center of the sensor array coincident with the optical axis of the lens, and the horizontal and vertical axes of the sensor array aligned with the respective horizontal and vertical axes of a scene imaged by the lens.

5. The method of claim 4, further comprising:

providing a first alignment feature on each of the distal ends of the projections that, in combination with the other ones of such first distal end alignment features, defines a first plane that is parallel to the focal plane of the lens;

forming a first corresponding, complementary alignment feature in each of the recesses that, in combination with the other ones of such first recess alignment features, defines a second plane that is parallel to the plane of the sensor array; and

,

controlling the depth of the first recess alignment features such that, when corresponding pairs of the first distal end alignment features and the first recess alignment features are engaged with each other, the plane of the sensor array is coplanar with the focal plane of the lens.

6. The method of claim 4, further comprising:

providing a second alignment feature on each of the distal ends of the projections that is located a predetermined radial distance from the optical axis of the lens; and

,

forming a second, corresponding, complementary alignment feature in each of the recesses that is located at the same, predetermined radial distance from the center of the sensor array such that, when corresponding pairs of the second distal end alignment features and the second recess alignment features are engaged with each other, the center of the sensor array is positioned coincident with the optical axis of the lens.

7. The method of claim 4, further comprising:

providing a second alignment feature on each of the distal ends of the projections that is oriented at a predetermined angular position relative to the horizontal and vertical axes of the scene imaged by the lens; and

,

forming a second, corresponding, complementary alignment feature in each of the recesses that is located at the same, predetermined angular orientation relative to the horizontal and vertical axes of the sensor array such that, when corresponding pairs of the second distal end alignment features and the second, complementary recess alignment features are engaged with each other, the horizontal and vertical axes of the sensor array are aligned with the horizontal and vertical axes of the scene imaged by the lens, respectively.

8. The method of claim 4, further comprising locating corresponding pairs of the projections and the recesses at radially asymmetrical positions relative to the optical axis of the lens and the center of the sensor array, respectively, such that the sensor array can be mounted to the lens in only one orientation relative thereto.

9. The method of claim 4, wherein corresponding pairs of the projections and the recesses are located at radially symmetrical positions relative to the optical axis of the lens and the center of the sensor array, respectively, and further comprising keying one of the corresponding pairs of the projections and the recesses uniquely to each other such that the sensor array can be mounted to the lens in only one orientation relative thereto.

10. The method of claim 4, wherein the sensor array package comprises a transparent window overlying the sensor array, and wherein milling the recesses into the package of the sensor array comprises milling the recesses into a margin of the window.

11. The method of claim 10, wherein each of the recesses comprises a slot or a bore milled into the margin of the window.

12. Apparatus for mounting a packaged optical sensor array to a lens in optical alignment therewith, comprising:

a fixture attached to the lens for mounting the package of the sensor array to the lens, the fixture comprising a plurality of mounting features located at predetermined positions measured relative to a focal plane of the lens, an optical axis of the lens, and horizontal and vertical axes of a scene imaged by the lens; and

,

corresponding, complementary mounting features formed in the package of the sensor array at positions measured relative to the absolute locations of the plane, the center, and horizontal and vertical axes of the sensor array in the package, said positions corresponding to said predetermined positions of the mounting features on the fixture measured relative to the focal plane of the lens, the optical axis of the lens, and the horizontal and vertical axes of a scene imaged by the lens, respectively, such that,

when the mounting features on the fixture are engaged with the corresponding, complementary mounting features in the package of the sensor array, the sensor array is held mounted to the lens, with the plane of the sensor array coplanar with the focal plane of the lens, the center of the sensor array coincident with the optical axis of the lens, and the horizontal and vertical axes of the sensor array aligned with the respective horizontal and vertical axes of the scene imaged by the lens.

13. The apparatus of claim 12, further comprising automated pattern recognition apparatus for finding at least one of said absolute locations of the plane, the center, and the horizontal and vertical axes of the sensor array within the package.

14. The apparatus of claim 13, further comprising computer-controlled milling apparatus for milling said mounting features into the package of the sensor array at said measured positions and positioned in accordance with said absolute sensor array feature locations found by said automated pattern recognition apparatus.

15. The apparatus of claim 12, further comprising:

a plurality of projections mounted on the lens at distinct, predetermined polar coordinates measured relative to the optical axis of the lens and the horizontal and vertical axes of a scene imaged by the lens, the projections extending outward from the lens toward the focal plane of the lens and in a direction parallel to the optical axis thereof, each projection having a distal end; and

,

a plurality of recesses milled into the package of the sensor array at polar coordinates measured relative to the center and the horizontal and vertical axes of the sensor array that correspond to said distinct, predetermined polar coordinates of said projections, respectively, the recesses being adapted to receive a corresponding one of the distal ends of the projections in a complementary engagement such that the sensor array is mounted to the lens, with the plane of the sensor array coplanar with the focal plane of the lens, the center of the sensor array coincident with the optical axis of the lens, and the horizontal and vertical axes of the sensor array aligned with the respective horizontal and vertical axes of a scene imaged by the lens.

16. The apparatus of claim 15, further comprising:

a first alignment feature provided on each of the distal ends of the projections that, in combination with the other ones of such first distal end alignment features, defines a first plane that is parallel to the focal plane of the lens;

a first corresponding, complementary alignment feature formed in each of the recesses that, in combination with the other ones of such first recess alignment features, defines a second plane that is parallel to the plane of the sensor array, the first recess alignment features having a depth that is controlled such that, when corresponding pairs of the first distal end alignment features and the first recess alignment features are engaged with each other, the plane of the sensor array is coplanar with the focal plane of the lens.

17. The apparatus of claim 15, further comprising:

a second alignment feature provided on each of the distal ends of the projections that is located a predetermined radial distance from the optical axis of the lens; and

,

a second, corresponding, complementary alignment feature formed in each of the recesses that is located at the same, predetermined radial distance from the center of the sensor array such that, when corresponding pairs of the second distal end alignment features and the second recess alignment features are engaged with each other, the center of the sensor array is positioned coincident with the optical axis of the lens.

18. The apparatus of claim 15, further comprising:

a second alignment feature provided on each of the distal ends of the projections that is oriented at a predetermined angular position relative to the horizontal and vertical axes of the scene imaged by the lens; and

,

a second, corresponding, complementary alignment feature formed in each of the recesses that is located at the same, predetermined angular orientation relative to the horizontal and vertical axes of the sensor array such that, when corresponding pairs of the second distal end alignment features and the second, complementary recess alignment features are engaged with each other, the horizontal and vertical axes of the sensor array are aligned with the horizontal and vertical axes of the scene imaged by the lens, respectively.

19. The apparatus of claim 15, wherein corresponding pairs of the projections and the recesses are located at radially asymmetrical positions relative to the optical axis of the lens and the center of the sensor array, respectively, such that the sensor array can be mounted to the lens in only one orientation relative thereto.

20. The apparatus of claim 15, wherein corresponding pairs of the projections and the recesses are located at radially symmetrical positions relative to the optical axis of the lens and the center of the sensor array, respectively, and wherein one of the corresponding pairs of the projections and the recesses are keyed uniquely to each other such that the sensor array can be mounted to the lens in only one orientation relative thereto.

21. A method for manufacturing a packaged optical sensor array of the type that includes a substrate, a semiconductor chip mounted on the substrate, a planar photo sensor array formed on an upper surface of the chip, the array having a center and horizontal and vertical axes, and a transparent window through which the sensor array is exposed to incident light, the method comprising:

finding the absolute locations of the plane, the center, and the horizontal and vertical axes of the sensor array independently of any mechanical features of the sensor package; and

,

forming mounting features in the package at positions measured relative to the absolute locations found of the plane, the center, and the horizontal and vertical axes of the sensor array.

22. The method of claim 21, wherein forming the mounting features in the package comprises milling a plurality of recesses into the package at positions measured relative to the absolute locations found of the plane, the center, and the horizontal and vertical axes of the sensor array.

23. The method of claim 21, wherein finding the absolute locations of the plane, the center and the horizontal and vertical axes of the sensor array comprises finding at least one of said features automatically with computer-controlled optical pattern recognition apparatus.

24. The method of claim 22, wherein milling a plurality of recesses into the package comprises milling said recesses into said package with computer-controlled milling apparatus positioned in accordance with the absolute locations found of the plane, the center, and the horizontal and vertical axes of the sensor array.

25. The method of claim 22, wherein each of the recesses is formed to include a first alignment feature that is located in a plane parallel to the plane of the sensor array.

26. The method of claim 22, wherein each of the recesses is formed to include a second alignment feature that is located at a predetermined radial distance from the center of the sensor array.

27. The method of claim 22, wherein each of the recesses is formed to include a second alignment feature that is located at a predetermined angular orientation relative to the horizontal and vertical axes of the sensor array.

28. A packaged optical sensor array, comprising:

a substrate;

a semiconductor chip mounted on the substrate, the chip having a planar photo sensor array formed on an upper surface of the chip, the array having a center and horizontal and vertical axes;

a transparent window through which the sensor array is exposed to incident light; and

,

mounting features formed in the package of the sensor array at positions measured relative to the absolute locations of the plane, the center, and the horizontal and vertical axes of the sensor array within the package.

29. The packaged optical sensor array of claim 28, wherein the mounting features comprise a plurality of recesses milled into the package of the sensor array.

30. The packaged optical sensor array of claim 29, wherein each of the recesses includes a first alignment feature that is located in a plane parallel to the plane of the sensor array.

31. The packaged optical sensor array of claim 29, wherein each of the recesses includes a second alignment feature that is located at a predetermined radial distance from the center of the sensor array.

32. The packaged optical sensor array of claim 29, wherein each of the recesses includes a second alignment feature that is located at a predetermined angular orientation relative to the horizontal and vertical axes of the sensor array.

33. The packaged optical sensor array of claim 29, wherein the recesses comprise slots or bores milled into the window of the package.

34. The packaged optical sensor array of claim 29, wherein the recesses are located at bilaterally symmetrical positions relative to the center of the sensor array.