Imaging module and reader for, and method of, reading a target over a field of view by image capture with a visually prominent indicator of a center zone of the field of view

Patent metadata

Field	Value
Publication number	US-9639728-B1
Application number	US-201615248181-A
Country	US
Kind code	B1
Filing date	Aug 26, 2016
Priority date	Aug 26, 2016
Publication date	May 2, 2017
Grant date	May 2, 2017

Abstract

An imaging sensor of an imaging reader senses return light from a target to be read by image capture along an imaging axis over a field of view that extends along mutually orthogonal, horizontal and vertical axes. Two aiming light assemblies are offset from the sensor, and direct an aiming light pattern at the target. The pattern has an aiming mark in a central area of the pattern, and a pair of aiming light lines that are collinear along the horizontal axis. The visibility of the aiming mark is enhanced by optically configuring the aiming mark to be different in brightness relative to a remaining area of the pattern by specially configuring aiming lenses with regions of different optical power to forte each aiming light line of non-uniform brightness. The aiming mark of enhanced visibility constitutes a prominent visual indicator of a center zone of the field of view.

First claim

The invention claimed is:

1. An imaging module for reading a target by image capture over a range of working distances away from the module, comprising:
an imaging system including an imaging sensor for sensing light returning from the target along an imaging axis over a field of view that extends along mutually orthogonal, horizontal and vertical axes that are generally perpendicular to the imaging axis; and
an aiming light system offset from the imaging system and operative for directing an aiming light pattern at the target, for optically forming the aiming light pattern with an aiming mark in a central area of the aiming light pattern and with a pair of aiming light lines that are collinear along the horizontal axis, and for optically enhancing the visibility of the aiming mark relative to a remaining area of the aiming light pattern by optically configuring the aiming light lines to be of non-uniform brightness, the aiming mark of enhanced visibility constituting a prominent visual indicator of a center zone of the field of view in which the target is positioned over the range of working distances.

2. The module of claim 1 , wherein the aiming light system optically configures the aiming mark to be greater in brightness relative to the remaining area of the aiming light pattern.

3. The module of claim 1 , wherein the aiming light system includes a pair of aiming light assemblies spaced apart along the horizontal axis at opposite sides of the imaging sensor, and wherein the light assemblies include a pair of aiming light sources for emitting a pair of aiming lights along a pair of aiming axes, a pair of aiming source apertures through which the aiming lights respectively pass along the aiming axes, and a pair of aiming lenses for respectively optically modifying the aiming lights to form the aiming light pattern.

4. The module of claim 3 , wherein the aiming light sources are light emitting diodes, and wherein the aiming source apertures are elongated openings extending along the horizontal axis.

5. The module of claim 3 , wherein each aiming lens has an entrance surface on which the aiming lights are incident, and an exit surface from which the aiming lights are projected onto the target, and wherein each exit surface is a continuous, freeform surface that is free of discontinuities.

6. The module of claim 3 , wherein the aiming lenses are symmetrically located at opposite sides of the imaging axis; wherein each aiming lens has an inner high power region of greater optical power that is closer to the imaging axis, and an outer low power region of lesser optical power that is further from the imaging axis; wherein the inner high power regions project a major portion of the aiming lights onto the aiming mark; and wherein the outer low power regions project a minor portion of the aiming lights onto the remaining area of the aiming light pattern.

7. The module of claim 6 , wherein the inner high power regions and the outer low power regions are curved and merge smoothly together, and wherein the inner high power regions have a greater curvature than the outer low power regions.

8. The module of claim 6 , wherein each aiming lens has an optical power that increases along the horizontal axis toward the imaging axis, and wherein the brightness of each aiming light line increases along the horizontal axis toward the imaging axis.

9. The module of claim 3 , wherein the aiming lenses are of one-piece construction.

10. The module of claim 3 , and a light-transmissive window overlying the imaging sensor, and wherein the aiming lenses are of one-piece construction with the window.

11. An imaging reader for reading a target by image capture over a range of working distances away from the reader, comprising:
a housing having a light-transmissive window; and
an imaging module mounted in the housing, the module having
an imaging system including an imaging sensor for sensing light returning from the target along an imaging axis through the window over a field of view that extends along mutually orthogonal, horizontal and vertical axes that are generally perpendicular to the imaging axis, and
an aiming light system offset from the imaging system and operative for directing an aiming light pattern through the window at the target, for optically forming the aiming light pattern with an aiming mark in a central area of the aiming light pattern and with a pair of aiming light lines that are collinear along the horizontal axis, and for optically enhancing the visibility of the aiming mark relative to a remaining area of the aiming light pattern by optically configuring the aiming light lines to be of non-uniform brightness, the aiming mark of enhanced visibility constituting a prominent visual indicator of a center zone of the field of view in which the target is positioned over the range of working distances.

12. The reader of claim 11 , wherein the aiming light system includes a pair of aiming light assemblies spaced apart along the horizontal axis at opposite sides of the imaging sensor, and wherein the light assemblies include a pair of aiming light sources for emitting a pair of aiming lights along a pair of aiming axes, a pair of aiming source apertures through which the aiming lights respectively pass along the aiming axes, and a pair of aiming lenses for respectively optically modifying the aiming lights to form the aiming light pattern; and wherein each aiming lens has an entrance surface on which the aiming lights are incident, and an exit surface from which the aiming lights are projected onto the target, and wherein each exit surface is a continuous, freeform surface that is free of discontinuities.

13. The reader of claim 12 , wherein the aiming lenses are symmetrically located at opposite sides of the imaging axis; wherein each aiming lens has an inner high power region of greater optical power that is closer to the imaging axis, and an outer low power region of lesser optical power that is further from the imaging axis; wherein the inner high power regions project a major portion of the aiming lights onto the aiming mark; wherein the outer low power regions project a minor portion of the aiming lights onto the remaining area of the aiming light pattern; wherein each aiming lens has an optical power that increases along the horizontal axis toward the imaging axis; and wherein the brightness of each aiming light line increases along the horizontal axis toward the imaging axis.

14. A method of reading a target by image capture over a range of working distances away from an imaging reader, the method comprising:
sensing light returning from the target along an imaging axis over a field of view that extends along mutually orthogonal, horizontal and vertical axes that are generally perpendicular to the imaging axis;
directing an aiming light pattern at the target;
optically forming the aiming light pattern with an aiming mark in a central area of the aiming light pattern and with a pair of aiming light lines that are collinear along the horizontal axis; and
optically enhancing the visibility of the aiming mark relative to a remaining area of the aiming light pattern by optically configuring the aiming light lines to be of non-uniform brightness, the aiming mark of enhanced visibility constituting a prominent visual indicator of a center zone of the field of view in which the target is positioned over the range of working distances.

15. The method of claim 14 , wherein the optical enhancing is performed by configuring the aiming mark to be greater in brightness relative to the remaining area of the aiming light pattern.

Assignees

• Symbol Technologies Llc

Inventors

• Handshaw Darran Michael
• Vinogradov Igor
• Gurevich Vladimir

Classifications

• G06K2007/10485

  Arrangement of optical elements · CPC title

• G06K2207/1011

  Aiming · CPC title

• G06K7/10732 Primary

  Light sources · CPC title

• G02B23/00

  Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices · CPC title

• G06K7/10831

  Arrangement of optical elements, e.g. lenses, mirrors, prisms (optical elements per se G02B) · CPC title