Laser scanning modules embodying silicone scan element with torsional hinges

• US 8,915,439 B2
• Filed: 02/06/2012
• Issued: 12/23/2014
• Est. Priority Date: 02/06/2012
• Status: Active Grant

• Current Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Original Assignee: Metrologic Instruments Incorporated (Honeywell International Inc.)
• Inventors: Feng, Chen, Rueblinger, Gregory, Wang, Ynjiun Paul
• Primary Examiner(s): Mikels, Matthew
• Application Number:
  US13/367,047
• Publication Number:
  US 20130200158A1
• Time in Patent Office: 1,051 Days
• Field of Search: 235/462
• US Class Current: 235/462.01
• CPC Class Codes: G02B 26/105 with one or more pivoting mirrors or galvano-mirrors G02B26/101 takes precedence
• CPC Class Codes: G06K 2007/10485 Arrangement of optical elements
• CPC Class Codes: G06K 7/10633 by oscillation

Abstract

Laser scanning module employing a scan mirror and magnet rotor subassembly supported by a stationary stator structure. The scan mirror and magnet rotor subassembly includes: a silicone frame having a pair of silicone torsional hinges (i.e. posts) aligned along a scan axis and a supported by a pair of support elements associated with the stator structure, to support the scan mirror and magnet rotor subassembly. When the scan mirror and magnet rotor subassembly is rotated about its scan axis, by forces generated by an electromagnetic coil structure acting on the permanent magnet mounted on silicone frame, the silicone torsional hinges are elastically distorted and generate linear restoring forces which return the rotor subassembly back to its home position about the scan axis.

Claims

1. A laser scanning assembly for installation within a housing, said laser scanning assembly comprising:

a scan mirror and magnet rotor subassembly having

a silicone frame having a pair of silicone torsional hinges aligned along a scan axis passing through said silicone frame;

a scan mirror mounted on said silicone frame; and

a permanent magnet mounted on said silicone frame; and

a stator structure mounted stationary relative to a housing, and including a frame holder having

a support member for supporting said frame holder within said housing;

a pair of support elements provided on said frame holder, so that said pair of silicone torsional hinges are mounted to said support elements along the scan axis, and torsionally support said scan mirror and magnet rotor subassembly and allow said scan mirror and magnet rotor assembly to oscillate freely about said scan axis passing through said silicone torsional hinges and said support elements; and

an omni-directional rotor motion limiting arrangement for limiting rotational and translational motion of said scan mirror and magnet rotor subassembly, when said laser scanning assembly is subjected to external shock forces exceeding a predetermined threshold.

2. The laser scanning assembly of claim 1, wherein said pair of silicone torsional hinges generate an elastic returning force to said scan mirror and magnet rotor subassembly, the magnitude of which is linearly proportional to the magnitude of the angle of rotation of said scan mirror and magnet rotor subassembly about said scan axis.

3. The laser scanning assembly of claim 2, wherein said silicone frame has a top end and a bottom end, and wherein said omni-directional rotor motion limiting arrangement comprises a pair of stops formed on the top and bottom ends of said silicone frame.

4. The laser scanning assembly of claim 3, wherein said omni-directional rotor motion limiting arrangement further comprises projections extending from said support elements, and wherein said projections strike said pair of stops when said scan mirror and magnet rotor subassembly is subject to said external shock forces, thereby limiting the angular rotational displacement that said scan mirror and magnet rotor subassembly.

5. The laser scanning assembly of claim 4, wherein said silicone frame has a top surface and a bottom surface;

wherein said omni-directional rotor motion limiting arrangement further comprises said top and bottom surfaces; and

wherein said support element strike said top and bottom surfaces of said silicone frame when said scan mirror and magnet rotor subassembly is subjected to said external shock forces, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a first coordinate direction parallel with said scan axis.

6. The laser scanning assembly of claim 5, wherein said silicone frame has a front surface and a rear surface, and said frame holder has a front surface;

wherein said omni-directional rotor motion limiting arrangement further comprises said rear surface of said silicone frame; and

wherein said rear surface of said silicone frame strikes the front surface of said frame holder when said laser scanning assembly is subject to external shock forces exceeding said particular threshold, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a second coordinate axis, orthogonal to the front surface of said frame holder, in response to said external shock forces.

7. The laser scanning assembly of claim 6, wherein said omni-directional rotor motion limiting arrangement further comprises said pair of stops on the top and bottom ends of said silicone frame;

and wherein said pair of stops strike said projections on said support elements of said frame holder when said laser scanning assembly is subjected to external shock forces exceeding said particular threshold, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a third coordinate axis, orthogonal to said scan axis and parallel the front surface of said frame holder, in response to said external shock forces.

8. The laser scanning assembly of claim 3, wherein said omni-directional rotor motion limiting arrangement comprises:

a set of stop projections and/or stop surfaces on the rear surface of said stator structure; and

a plate structure mounted over said magnet and having a first pair of projections formed along a first axis for engaging with one or more of said stop projections and/or stop surfaces on said stator structure, thereby limiting the rotational displacement of said scan mirror and magnet rotor subassembly about said scan axis, when said laser scanning assembly is subjected to external shock forces exceeding said predetermined threshold.

9. The laser scanning assembly of claim 8, wherein said plate structure further comprises a second pair of projections formed along a second axis, orthogonal to said first axis, and wherein said second pair of projections strike one or more of said stop projections and/or stop surfaces on said stator structure, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a first coordinate direction orthogonal with said scan axis, in response to said external shock forces.

10. The laser scanning assembly of claim 9, wherein said frame holder has an opening with a top opening surface and a bottom opening surface, wherein said omni-directional rotor motion limiting arrangement further comprises said top opening surface of said silicone frame;

and wherein said top opening surface strikes said top opening surface of said opening on said stator structure and/or said bottom opening surface of said silicone frame strikes said bottom opening surface of said opening on said stator structure, when said laser scanning assembly is subject to external shock forces exceeding said particular threshold, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a second coordinate axis, parallel to said scan axis.

11. The laser scanning assembly of claim 10, wherein said omni-directional rotor motion limiting arrangement further comprises said second pair of projections;

and wherein said second pair of projections strikes one or more of said stop projections and/or stop surfaces on said stator structure, when said laser scanning assembly is subjected to external shock forces exceeding said particular threshold, thereby limiting the linear displacement of said scan mirror and magnet rotor subassembly along a third coordinate axis, orthogonal to said scan axis and said first and second coordinate axes.

12. The laser scanning assembly of claim 1, wherein said silicone frame is molded from a liquid silicone rubber.

13. The laser scanning assembly of claim 1, wherein said pair of torsional hinges are realized as torsional posts.

14. The laser scanning assembly of claim 1, wherein said pair of said torsional posts has a circular cross-sectional dimension.

15. The laser scanning assembly of claim 1, wherein said pair of said torsional posts has a rectangular cross-sectional dimension.

16. The laser scanning assembly of claim 1, wherein each said support element has an aperture formed therein, and said pair of silicone torsional hinges are mounted through said apertures formed in said support elements.

17. The laser scanning assembly of claim 1, wherein said support member has a support portion which is mounted within a recess formed in said housing.

18. The laser scanning assembly of claim 1, wherein said first side and said second side of said silicone frame reside on the same side of said scan axis passing through said silicone frame.

19. A laser scanning module comprising said laser scanning assembly of claim 1.

20. A code symbol reading system comprising:

a system housing with a light transmission aperture; and

a laser scanning assembly according to claim 1 mounted in said system housing.

21. A code symbol reading system comprising:

a system housing with a light transmission aperture; and

a laser scanning module according to claim 19 mounted in said system housing.

22. A laser scanning assembly for installation within a scanning system having a system housing, said laser scanning assembly comprising:

a scan mirror and magnet rotor subassembly having

an elastomeric frame having a pair of elastomeric torsional hinges aligned along a scan axis passing through said elastomeric one frame;

a scan mirror mounted on said elastomeric frame; and

a permanent magnet mounted on said elastomeric frame; and

a stator structure mounted stationary relative to said system housing, and including a frame holder having

a support member for supporting said frame holder within said system housing, and

support elements provided on said frame holder, so that said pair of elastomeric torsional hinges are mounted to said support elements along the scan axis, and torsionally support said scan mirror and magnet rotor subassembly and allow said scan mirror and magnet rotor assembly to oscillate freely about said scan axis passing through said elastomeric torsional hinges and said support elements;

wherein said pair of elastomeric torsional hinges generate an elastic returning force to said scan mirror and magnet rotor subassembly, the magnitude of which is linearly proportional to the magnitude of the angle of rotation of said scan mirror and magnet rotor subassembly about said scan axis.