LASER SCANNING MODULES EMBODYING SILICONE SCAN ELEMENT WITH TORSIONAL HINGES

• US 20150129659A1
• Filed: 12/16/2014
• Published: 05/14/2015
• 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
• Granted Patent: US 9,158,951 B2
• Time in Patent Office: Days
• US Class Current: 235/462.36
• 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

A laser scanning module employs 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, comprising:

a frame holder mounted stationary relative to a housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges;

(i) is aligned along a scan axis passing through the silicone frame;

(ii) torsionally supports the scan mirror; and

(iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.

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

3. The laser scanning assembly of claim 1, wherein:

the silicone frame has a top end and a bottom end; and

the omni-directional rotor motion limiting structure comprises a pair of stops formed on the top and bottom ends of the silicone frame.

4. The laser scanning assembly of claim 3, wherein:

the omni-directional rotor motion limiting structure comprises projections extending from the frame holder; and

the projections strike the pair of stops when the laser scanning assembly is subject to external shock forces, thereby limiting the angular rotational displacement of the scan mirror and the magnet.

5. The laser scanning assembly of claim 4, wherein:

the silicone frame has a top surface and a bottom surface; and

the frame holder strikes the top and bottom surfaces of the silicone frame when the laser scanning assembly is subjected to the external shock forces, thereby limiting the linear displacement of the scan mirror and the magnet along a first coordinate direction parallel with the scan axis.

6. The laser scanning assembly of claim 5, wherein:

the silicone frame has a front surface and a rear surface;

the frame holder has a front surface; and

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

7. The laser scanning assembly of claim 6, wherein the pair of stops on the top and bottom ends of the silicone frame strike the projections extending from the frame holder when the laser scanning assembly is subjected to external shock forces exceeding the particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a third coordinate axis, orthogonal to the scan axis and parallel to the front surface of the frame holder, in response to the external shock forces.

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

a set of stop projections and/or stop surfaces on the rear surface of the frame holder; and

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

9. The laser scanning assembly of claim 8, wherein:

the plate structure comprises a second pair of projections formed along a second axis, orthogonal to the first axis; and

the second pair of projections strike one or more of the stop projections and/or stop surfaces on the frame holder, thereby limiting the linear displacement of the scan mirror and the magnet along a first coordinate direction orthogonal with the scan axis, in response to the external shock forces.

10. The laser scanning assembly of claim 9, wherein:

the frame holder has an opening with a top opening surface and a bottom opening surface; and

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

11. The laser scanning assembly of claim 10, wherein the second pair of projections of the plate structure strikes one or more of the stop projections and/or stop surfaces on the frame holder, when the laser scanning assembly is subjected to external shock forces exceeding the particular threshold, thereby limiting the linear displacement of the scan mirror and the magnet along a third coordinate axis, orthogonal to the scan axis and the first and second coordinate axes.

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

13. The laser scanning assembly of claim 1, wherein each of the pair of torsional hinges comprises a torsional post.

14. The laser scanning assembly of claim 13, wherein each of the torsional posts has a circular cross-sectional dimension.

15. The laser scanning assembly of claim 13, wherein each of the torsional posts has a rectangular cross-sectional dimension.

16. The laser scanning assembly of claim 1, wherein the frame holder comprises a support portion mounted within a recess formed in the housing.

17. The laser scanning assembly of claim 1, wherein a first side and a second side of the silicone frame reside on the same side of the scan axis.

18. A laser scanning module comprising:

a laser drive circuit for generating laser drive current signals to a laser source; and

a laser scanning assembly, comprising;

a frame holder mounted stationary relative to a housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges;

(i) is aligned along a scan axis passing through the silicone frame;

(ii) torsionally supports the scan mirror; and

(iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.

19. The laser scanning module of claim 18, wherein:

the silicone frame has a top end and a bottom end; and

the omni-directional rotor motion limiting structure comprises a pair of stops formed on the top and bottom ends of the silicone frame.

20. A code symbol reading system comprising:

a system housing;

a laser source mounted in the system housing;

a laser drive circuit, mounted in the system housing, for generating laser drive current signals to the laser source; and

a laser scanning assembly, comprising;

a frame holder mounted stationary relative to the system housing;

a silicone frame supporting a scan mirror and a magnet, the silicone frame comprising a pair of silicone torsional hinges over-molded to the frame holder, wherein the pair of silicone torsional hinges;

(i) is aligned along a scan axis passing through the silicone frame;

(ii) torsionally supports the scan mirror; and

(iii) allows the scan mirror and the magnet to oscillate freely about the scan axis passing through the pair of silicone torsional hinges; and

an omni-directional rotor motion limiting structure for limiting rotational and translational motion of the frame holder and silicone frame.