Imaging optical code reader having selectable depths of field

• US 7,025,271 B2
• Filed: 04/02/2003
• Issued: 04/11/2006
• Est. Priority Date: 12/18/2002
• Status: Expired due to Term

• Current Assignee: Symbol Technologies, LLC (Zebra Technologies Corporation)
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Carlson, Brad, Shi, Tsi David, Dvorkis, Paul, Krichever, Mark, Breytman, Alex
• Primary Examiner(s): Stcyr, Daniel
• Assistant Examiner(s): Hess, Daniel A.
• Application Number:
  US10/405,812
• Publication Number:
  US 20040118918A1
• Time in Patent Office: 1,105 Days
• Field of Search: 235/462.22, 235/462.23, 235/472.01, 235/462.24, 235/462.45
• US Class Current: 235/462.22
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 7/0004 Hybrid readers
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10386 the interrogation device being of the portable or hand-handheld type, e.g. incorporated in ubiquitous hand-held devices such as PDA or mobile phone, or in the form of a portable dedicated RFID reader
• CPC Class Codes: G06K 7/10722 Photodetector array or CCD scanning
• CPC Class Codes: G06K 7/10811 Focalisation

Abstract

Several optical systems for imaging engines of imaging optical code readers are disclosed. Each optical system includes the abilities to change the depth of field of the imaging field and to adjust a focus quality of the imaging field. The disclosed structures for changing the depth of field of the disclosed optical systems allow for the automatic or manual selection of one of a plurality of depths of field.

Claims

1. An optical system for an optical code reader comprising:

first and second lens assemblies having respective first and second depths of field, and respective first and second input optical axes;

at least one optical element having a transmissive state and a reflective state positioned in at least the first input optical axis to provide incident light from the first lens assembly to an image sensor when the at least one optical element is in the transmissive state and to provide incident light from the second lens assembly to the image sensor when the at least one optical element is in the reflective state; and

control circuitry for applying a voltage to the at least one optical element for switching the at least one optical element between the transmissive and reflective states to switch between the first and second depths of field.

2. The optical system of claim 1, wherein the optical system is housed within the optical code reader, said optical coder reader comprising a trigger assembly in operative communication with the control circuitry, wherein manual actuation of the trigger assembly causes the applied voltage to change for changing the depth of field of the optical code reader.

3. The optical system of claim 1, wherein the optical system is housed within the optical code reader, said optical code reader comprising a switch in operative communication with the control circuitry, wherein manual actuation of the switch causes the applied voltage to change for selectively controlling the depth of field of the optical code reader.

4. The optical system of claim 1, wherein the optical system is a component of an imaging engine.

5. The optical system of claim 1, wherein the optical system is housed within the optical code reader, said optical code reader comprising means for decoding an optical code imaged by an image sensor of the optical system.

6. The optical system of claim 1, wherein the optical system is housed within the optical code reader, said optical code reader comprising means for determining a distance between the optical code reader and an optical code.

7. The optical system of claim 1, wherein the optical system is housed within the optical code reader, said optical code reader comprising means for auto-focusing to adjust a focus quality of the optical system.

8. An imaging system for reading an optical code comprising:

a photo sensor employing an array of cells for producing electrical signals responsive to an image directed to said sensor;

an optical system for directing images to the photo sensor, wherein the optical system includes at least one electrically operative optical element for electronically switching between at least two states to vary the optical properties of the image directed to the photo sensor, wherein the at least one optical element is at least one electronic mirror; and

means for controlling the at least one electronic mirror to select an image of the optical code that is readily decodable.

9. The imaging system of claim 8, wherein the at least one optical element is switched between the at least two states to provide different depths of field.

10. The imaging system of claim 8, wherein the at least one optical element is switched between the at least two states to provide different focal distances.

11. The imaging system of claim 8, wherein the imaging system is housed within an optical code reader, said optical coder reader comprising a trigger assembly, wherein manual actuation of the trigger assembly causes the at least one electrically operative optical element to switch from one state to another state of said at least two states.

12. The imaging system of claim 8, wherein the imaging system is housed within an optical code reader, said optical code reader comprising a switch, wherein manual actuation of the switch causes the at least one electrically operative optical element to switch from one state to another state of said at least two states.

13. The imaging system of claim 8, wherein the imaging system is housed within an optical code reader, said optical code reader comprising means for decoding a read optical code.

14. The imaging system of claim 8, wherein the imaging system is housed within an optical code reader, said optical code reader comprising means for determining a distance between the optical code reader and an optical code.

15. The imaging system of claim 8, wherein the imaging system is housed within an optical code reader, said optical code reader comprising means for auto-focusing to adjust a focus quality of the imaging system.

16. A method of operation for an optical system, said method comprising:

providing first and second lens assemblies having respective first and second depths of field, and respective first and second input optical axes;

positioning at least one optical element having a transmissive state and a reflective state in at least the first input optical axis to provide incident light from the first lens assembly to an image sensor when the at least one optical element is in the transmissive state and to provide incident light from the second lens assembly to the image sensor when the at least one optical element is in the reflective state; and

applying a voltage to the at least one optical element for switching the at least one optical element between the transmissive and reflective states to switch between the first and second depths of field.

17. The method of claim 16, further comprising providing a manually-actuated switch for manually causing the applied voltage to change for selectively controlling the depth of field.

18. The method of claim 16, wherein the optical system is a component of an imaging engine.

19. The method of claim 16, further comprising housing the optical system within an optical code reader, said optical code reader comprising means for decoding an optical code imaged by an image sensor of the optical system.

20. The method of claim 16, further comprising housing the optical system within an optical code reader, said optical code reader comprising means for determining a distance between the optical code reader and an optical code.

21. The method of claim 16, further comprising housing the optical system within an optical code reader, said optical code reader comprising means for auto-focusing to adjust a focus quality of the optical system.

22. A method of operation for an imaging system, said method comprising:

providing a photo sensor employing an array of cells for producing electrical signals responsive to an image directed to said sensor;

providing an optical system for directing images to the photo sensor, wherein the optical system includes at least one electrically operative optical element for electronically switching between at least two states to vary the optical properties of the image directed to the photo sensor, wherein the at least one optical element is at least one electronic mirror; and

controlling the at least one electronic mirror to select an image of the optical code that is readily decodable.

23. The method of claim 22, further comprising housing the imaging system within an optical code reader, said optical coder reader comprising a trigger assembly, wherein manual actuation of the trigger assembly causes the at least one electrically operative optical element to switch from one state to another state of said at least two states.

24. The method of claim 22, further comprising housing the imaging system within an optical code reader, said optical code reader comprising a switch, wherein manual actuation of the switch causes the at least one electrically operative optical element to switch from one state to another state of said at least two states.

25. The method of claim 22, further comprising housing the imaging system within an optical code reader, said optical code reader comprising means for decoding a read optical code.

26. The method of claim 22, further comprising housing the imaging system within an optical code reader, said optical code reader comprising means for determining a distance between the optical code reader and an optical code and means for auto-focusing to adjust a focus quality of the imaging system.