Imaging apparatus having imaging lens

• US 8,978,981 B2
• Filed: 06/27/2012
• Issued: 03/17/2015
• Est. Priority Date: 06/27/2012
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Guan, Yiyi
• Primary Examiner(s): Frech, Karl D
• Application Number:
  US13/534,959
• Publication Number:
  US 20140002699A1
• Time in Patent Office: 993 Days
• Field of Search: 235/462.1, 235/462.04, 235/462.13, 235/462.11
• US Class Current: 235/462.11
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 9/04 having two components only
• CPC Class Codes: H04N 23/56 provided with illuminating means
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 25/134 based on three different wavelength filter elements
• CPC Class Codes: H04N 25/611 Correction of chromatic aberration

Abstract

There is set forth herein in one embodiment an imaging apparatus having an imaging assembly and an illumination assembly. The imaging assembly can comprise an imaging lens and an image sensor array. The illumination assembly can include a light source bank having one or more light source. The imaging assembly can define a field of view on a substrate and the illumination assembly can project light within the field of view. The imaging apparatus can be configured so that the illumination assembly during an exposure period of the imaging assembly emits light that spans multiple visible color wavelength bands.

Claims

1. An imaging apparatus comprising:

an imaging assembly including an imaging lens and an image sensor array, the imaging assembly defining a field of view, the image sensor array having a plurality a pixels, the plurality of pixels including color sensitive pixels having wavelength selective color filter elements;

an illumination assembly that, during a frame exposure period of the imaging assembly simultaneously projects on a target light within the blue wavelength band, the green wavelength band and the red wavelength band;

wherein the imaging lens is a two element glass imaging lens, the imaging lens having a first glass lens element and a second glass element;

wherein the imaging apparatus captures a frame of image data representing light incident of the image sensor array during an exposure period; and

wherein the imaging apparatus includes a pass band filter that selectively passes light within first second and third pass bands, the first pass band being defined in the blue wavelength band, the second pass band being defined in the green wavelength band, the third pass band being defined in the red wavelength band;

wherein the imaging apparatus processes the frame of image data for attempting to decode decodable; and

wherein the imaging lens has a chromatic aberration to effective focal length ratio of less than 0.025.

2. The imaging apparatus of claim 1, wherein the first pass band is separated from the second pass band and wherein the second pass band is separated from the third pass band.

3. The imaging apparatus of claim 1, wherein the imaging apparatus includes a hand held housing in which the image sensor array is disposed.

4. The imaging apparatus of claim 1, wherein the imaging lens has a chromatic aberration to effective focal length ratio of less than 0.020.

5. The imaging apparatus of claim 1, wherein the illumination assembly comprises a single light source.

6. The imaging apparatus of claim 1, wherein the illumination assembly includes a white light source emitting light that spans multiple visible color wavelength bands.

7. The imaging apparatus of claim 1, wherein the imaging lens includes a chromatic aberration of less than would be exhibited by the imaging lens if the imaging lens were optimized in a single broad band configuration.

8. The imaging apparatus of claim 1, wherein the first lens element has a light entry surface curvature greater than a light entry surface curvature that would be exhibited by the first lens element if the imaging lens were optimized in a single broad band configuration.

9. The imaging apparatus of claim 1, wherein the first lens element has a light entry surface curvature greater than a light entry surface curvature that would be exhibited by the first lens element if the imaging lens were optimized in a single broad band configuration.

10. The imaging apparatus of claim 1, wherein the first lens element has a light entry surface curvature greater than a light entry surface curvature that would be exhibited by the first lens element if the imaging lens were optimized in a single broad band configuration.

11. The imaging apparatus of claim 1, wherein the second lens element has a light entry surface curvature greater than a light entry surface curvature that would be exhibited by the second lens element if the imaging lens were optimized in a single broad band configuration.

12. The imaging apparatus of claim 1, wherein the first and second lens elements have indices of refraction reduced relative to indices of refraction that would be exhibited by the first and second lens elements if the imaging lens were optimized in a single broad band configuration.

13. The imaging apparatus of claim 1, wherein the first and second lens elements have V numbers increased relative to V numbers that would be exhibited by the first and second lens elements if the imaging lens were optimized in a single broad band configuration.

14. The imaging apparatus of claim 1, wherein the first lens element and the second lens element are devoid of aspherical light entry and light exit lens surfaces.

15. A method comprising:

defining first second and third configurations, wherein the first second and third configurations are defined to match first second and third pass bands of a multiple pass band filter;

defining a fourth configuration having first second and third wavelengths, respectively, within the first second and third pass bands;

providing an imaging lens by establishing merit functions within the four configurations to seek an optimized solution for the first, second and third pass bands;

wherein the imaging lens has a chromatic aberration to effective focal length ratio of less than 0.025.

16. The method of claim 15, wherein the method includes incorporating the imaging lens into an imaging apparatus having the multiple pass band filter.

17. The method of claim 15, wherein the method includes incorporating the imaging lens into an imaging apparatus having an image sensor array including color sensitive pixels and indicia decoding capability.

18. A method for reducing chromatic aberrations of an imaging lens having first and second lens elements and a chromatic aberration to effective focal length ratio of less than 0.025, the method comprising two or more of (a) through (h);

(a) increasing a curvature of a light entry;

(b) increasing a curvature of a light exit surface of the first lens element;

(c) increasing a curvature of a light entry surface of the second lens element;

(d) increasing a curvature of a light exit surface of the second lens element;

(e) decreasing an index of refraction of the first lens element;

(f) decreasing an index of refraction of the second lens element;

(g) increasing a V number of the first lens element;

(h) increasing a V number of the second lens element.

19. The method of claim 18, wherein the method includes performing three or more of (a) through (h);

(a) increasing a curvature of a light entry;

(b) increasing a curvature of a light exit surface of the first lens element;

(c) increasing a curvature of a light entry surface of the second lens element;

(d) increasing a curvature of a light exit surface of the second lens element;

(e) decreasing an index of refraction of the first lens element;

(f) decreasing an index of refraction of the second lens element;

(g) increasing a V number of the first lens element;

(h) increasing a V number of the second lens element.

20. The method of claim 18, wherein the method includes performing each of (a) through (h);

(a) increasing a curvature of a light entry;

(b) increasing a curvature of a light exit surface of the first lens element;

(c) increasing a curvature of a light entry surface of the second lens element;

(d) increasing a curvature of a light exit surface of the second lens element;

(e) decreasing an index of refraction of the first lens element;

(f) decreasing an index of refraction of the second lens element;

(g) increasing a V number of the first lens element;

(h) increasing a V number of the second lens element.