Segmented Reflective Optical System

• US 20100002273A1
• Filed: 07/26/2006
• Published: 01/07/2010
• Est. Priority Date: 07/26/2006
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Schissler, Dennis J., Schmidt, Jack H., Arterberry, John Herman, Majette, Mark W.
• Granted Patent: US 8,345,325 B2
• Time in Patent Office: Days
• US Class Current: 358/475
• CPC Class Codes: B23P 15/008 Rocket engine parts, e.g. nozzles, combustion chambers
• CPC Class Codes: H04N 1/03 with photodetectors arranged in a substantially linear array
• CPC Class Codes: H04N 1/0305 with multiple folds of the optical path
• CPC Class Codes: H04N 1/1934 Combination of arrays
• CPC Class Codes: H04N 1/1935 Optical means for mapping the whole or part of a scanned line onto the array
• CPC Class Codes: H04N 2201/02439 Positioning method
• CPC Class Codes: H04N 2201/02466 Mounting or supporting method
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

An optical system, used for scanning, forms an image using reflective optical surfaces. The system may be telecentric, and may form an image that is reduced in size as compared with the scanned original. Several image-forming optical channels may be combined to form a page-wide scanning array.

Claims

1. A scanner optical system, comprising:

at least two image-forming optical channels;

a generally linear electronic light sensor segment in each image-forming optical channel; and

at least two non-planar mirror segments in each image-forming optical channel;

and wherein each image-forming optical channel forms on the sensor segment, using the non-planar mirror segments, an image of a portion of a scan line.

2. The scanner optical system of claim 1, wherein each channel forms the image without the use of any refractive element having optical power.

3. The scanner optical system of claim 1, further comprising:

a multi-purpose optical element, the multi-purpose optical element further comprising, for each image-forming optical channel, an optical aperture and the at least two non-planar mirror segments.

4. The scanner optical system of claim 1, wherein the scan line portions imaged by adjacent channels overlap.

5. The scanner optical system of claim 1, wherein at least one of the non-planar mirror segments is aspheric.

6. The scanner optical system of claim 1, further comprising at least one page-wide planar mirror, and wherein a light path of each channel is folded for compactness.

7. The scanner optical system of claim 6, wherein at least one page-wide planar mirror further comprises:

a first side;

a second side opposite the first; and

a first-surface mirror coating on both sides;

and wherein, in the course of forming an image of the scan line portion, light from the scan line portion reflects from both sides.

8. The scanner optical system of claim 1, wherein each image-forming optical channel is substantially telecentric in object space.

9. The scanner optical system of claim 1, wherein the image formed by each image-forming channel is reduced in size in relation to the imaged scan line portion.

10. The scanner optical system of claim 9, wherein the image formed by each image-forming channel is nominally one half the size of the imaged scan line portion.

11. An imaging device, comprising:

a carriage comprising at least two image-forming optical channels, each channel forming an image of a portion of a scan line;

at least two non-planar mirror segments in each image-forming optical channel; and

a generally linear electronic light sensor in each image-forming optical channel;

and wherein the image is formed in each image-forming optical channel on the respective generally-linear electronic light sensor using the respective two non-planar mirror segments.

12. The imaging device of claim 11, wherein the imaging device is one of a flatbed scanner, a sheetfeed scanner, a photocopier, a facsimile machine, and a multi-function imaging device.

13. The imaging device of claim 11, configured to scan a reflective original item.

14. The imaging device of claim 11, configured to scan a transmissive original item.

15. The imaging device of claim 11, further comprising a multi-purpose optical element, the multipurpose optical element comprising for each image-forming optical channel the two non-planar mirror segments and an optical aperture.

16. The imaging device of claim 11, wherein each image-forming optical channel is substantially telecentric in object space.

17. The imaging device of claim 11, wherein the scan line portions imaged by adjacent image-forming optical channels overlap.

18. The imaging device of claim 11, wherein the image formed by each image-forming optical channel is reduced in size as compared with the scan line portion imaged.

19. A optical carriage for a scanner, comprising:

a carriage housing;

at least two image-forming optical channels substantially contained within the carriage housing;

at least two non-planar mirror segments in each image-forming optical channel; and

a generally linear electronic light sensor in each image-forming optical channel;

and wherein each image-forming optical channel, using the non-planar mirror segments, forms an image on the light sensor of a portion of the scan line.

20. The optical carriage of claim 19, further comprising a multi-purpose optical element that comprises for each image-forming optical channel, the at least two non-planar mirror segments and an optical aperture.

21. The optical carriage of claim 19 wherein each image-forming optical channel is substantially telecentric in object space.

22. The optical carriage of claim 19, further comprising a light source configured to illuminate the scan line on an original item.

23. The optical carriage of claim 22, wherein the light source emits light containing substantially all wavelengths in the visible spectrum.

24. The optical carriage of claim 23, wherein each generally-linear electronic light sensor further comprises at least a first row of pixels sensing light in a first subset of the visible spectrum, a second row of pixels sensing light in a second subset of the visible spectrum, and a third row of pixels sensing light in a third subset of the visible spectrum.

25. The optical carriage of claim 22, wherein the light source further comprises at least three light emitting devices that emit light of at least three different colors.

26. The optical carriage of claim 25, wherein each light emitting device is a light emitting diode.

27. The optical carriage of claim 25, wherein each generally linear electronic light sensor is sensitive to substantially the entire visible spectrum, and the optical carriage is configured to accomplish color scanning by reading each scan line multiple times, at least once with each different illumination color.

28. The optical carriage of claim 19, wherein one of the non-planar mirror segments serves the function of an optical aperture.

29. A method of scanning, comprising:

forming, in an optical carriage module, images of at least two scan line segments, the optical carriage module comprising at least two image-forming optical channels, each image-forming optical channel further comprising a generally linear optical sensor and at least two non-planar reflective surfaces, and each image-forming optical channel forming one of the images using the non-planar reflective surfaces of the channel;

illuminating, with a light source, the scan line on an original item;

causing relative motion between the original item and the optical carriage; and

generating digital values representing the distribution of light on the generally linear optical sensors.

30. The method of claim 29, further comprising placing all of the non-planar reflective surfaces of all of the channels and an optical aperture for each channel on a multi-purpose optical element.

31. The method of claim 29, wherein illuminating the scan line further comprises illuminating the scan line with a light source that emits light containing substantially all wavelengths in the visible spectrum.

32. The method of claim 29, wherein illuminating the scan line further comprises illuminating the scan line with at least three light emitting devices, each light emitting device emitting light containing wavelengths in a subset of the visible spectrum.

33. The method of claim 32, further comprising performing single-pass color scanning.

34. The method of claim 32, further comprising performing multiple-pass color scanning.

35. The method of claim 29, further comprising:

generating a digital image of a calibration target using the optical carriage module;

characterizing alignment errors in the optical carriage module by analyzing the digital image of the calibration target; and

compensating, based on the characterization, for the alignment errors by adjusting digital pixel values in a subsequent scanned image.

36. A multi-purpose optical element, comprising, for each image-forming optical channel in an optical system that comprises at least two image-forming optical channels, each image-forming optical channel forming, on a generally linear electronic light sensor, an image of a portion of a scan line:

at least two non-planar mirror segments; and

an optical aperture.

37. The multi-purpose optical element of claim 36, wherein during image formation, image-forming light in one image-forming channel reflects from one non-planar mirror segment of the channel, then passes through the optical aperture of the channel, and then reflects from the other non-planar mirror segment of the channel.

38. The multi-purpose optical element of claim 36, wherein the at least two non-planar mirror segments and the optical aperture of one image-forming channel are nominally identical to the at least two non-planar mirror segments and the optical aperture of another image-forming channel.

39. An optical carriage module for a scanner, comprising:

at least two page-wide generally planar mirrors;

at least two end datum blocks comprising mirror mounting surfaces for mounting the page-wide mirrors;

at least one spring clip for each end datum block, each spring clip holding the at least two page-wide mirrors against an end datum block; and

a carriage housing;

and wherein the page-wide mirrors, the end datum blocks, and the clips are comprised in an optical subassembly that is secured to the carriage housing.

40. The optical carriage module of claim 39, wherein the end datum blocks are substantially clear and are secured to the carriage housing using an adhesive cured by application of light.

41. The optical carriage module of claim 39, further comprising:

a relatively flexible optical component;

a middle datum block having a datum surface referencing the relatively flexible optical component;

a datum surface on each end datum block referencing the relatively flexible optical component.

42. The optical carriage module of claim 41, further comprising at least one spring feature on the middle datum block, the at least one spring feature configured to hold the datum surface of the middle datum block against an alignment fixture while the middle datum block is secured to the carriage housing using an adhesive.

43. The optical carriage of claim 42, wherein after curing of the adhesive, the datum surfaces on the end datum blocks and the datum surface on the middle datum block are substantially coplanar.

44. The optical carriage module of claim 41, further comprising:

a lid; and

at least one spring interposed between the lid and the relatively flexible optical component, the at least one spring holding the relatively flexible optical component against at least one datum surface.

45. A method of assembling an optical carriage module for a scanner, comprising:

forming an optical subassembly by holding at least two page-wide generally planar mirrors against mounting surfaces on at least two end datum blocks surfaces using at least one spring clip for each datum block; and

securing the optical subassembly into a carriage housing.

46. The method of claim 45, wherein securing the optical assembly into the carriage housing further comprises:

placing an adhesive between each end datum block and the carriage housing; and

curing the adhesive by flooding it with light through the end datum blocks.

47. The method of claim 45, wherein each end datum block comprises a datum surface, and further comprising:

holding an alignment fixture against the datum surfaces of the end datum blocks;

placing a middle datum block between the end datum blocks, the middle datum block having a datum surface and at least one spring feature that holds the middle datum block datum surface against the alignment fixture; and

securing the middle datum block to the carriage housing using an adhesive.

48. The method of claim 47, wherein after the middle datum block is secured to the carriage, the datum surfaces of the end datum blocks and the datum surface of the middle datum block are substantially coplanar.