Targeting system for a portable image reader
View Patent ↗A targeting system for a portable image reader, which advantageously combines a number of functions including alignment, aiming, framing and range finding and provides a wide imaging range with an optimal field of view, is described. The targeting system projects a predetermined pattern having two or more components onto the target such that the components maintain a uniform distance between one another to bound the target and further vary in size as a function of their distance between the image reader and the target. The targeting system comprises targeting LED's, apertures positioned over the targeting LED's, and cylindrical lenses positioned over the apertures. With this arrangement, at least two vertical lines are projected onto a target such that the lines maintain a uniform distance apart from one another, but vary in length as a function of the reader distance from the target. This allows the operator to quickly position the imaging device over a target.
1. An image reader comprising:
a circuit board;
an image sensor mounted on said circuit board;
an objective lens assembly having an objective lens axis positioned in front of said image sensor adapted to direct light from a target to the image sensor; and
a targeting system adapted to project a predetermined pattern having two or more components onto the target whereby the components maintain a uniform distance between one another to bound the target and whereby components vary in size as a function of their distance between the image reader and the target.
2. An image reader as claimed in claim 1 wherein the pattern components are two substantially parallel lines.
3. An image reader as claimed in claim 2 wherein the distance between the lines remains substantially constant and the lines vary in length as a function of the distance between the reader and the target.
4. An image reader as claimed in claim 3 wherein the targeting system comprises:
a first optical apparatus located adjacent to one side of the objective lens assembly and adapted to project one line onto the target; and
a second optical apparatus located adjacent to substantially the opposite side of the objective lens assembly adapted to project a second line onto the target.
5. An image reader as claimed in claim 4 wherein the first and second optical apparati each comprise:
a targeting illumination source;
an aperture having an elongated slit positioned in front of the illumination source; and
a cylindrical lens positioned in a corresponding orientation in front of the aperture.
6. An image reader as claimed in claim 5 wherein the targeting illumination source is a light emitting diode.
7. An image reader as claimed in claim 5 wherein the elongated slits are substantially perpendicular to a plane through the first and second optical apparati.
8. An image reader as claimed in claim 5 comprising an illumination assembly adapted to illuminate the target.
9. An image reader as claimed in claim 8 wherein the targeting system comprises:
a first optical apparatus and a second optical apparatus located in a first plane adjacent to opposite sides of the objective lens assembly and adapted to project two substantially parallel lines onto the target; and
a third optical apparatus and a fourth optical apparatus located in a second plane perpendicular to the first plane adjacent to opposite sides of the objective lens assembly and adapted to project two substantially parallel lines substantially perpendicular to the first and second optical apparatus parallel lines onto the target.
10. An image reader as claimed in claim 9 wherein the targeting illumination source is a light emitting diode.
11. An image reader as claimed in claim 9 wherein the elongated slits in the first and second apparati are substantially perpendicular to the first plane and the elongated slits in the third and fourth apparati are substantially perpendicular to the second plane.
12. An image reader as claimed in claim 9 comprising an illumination assembly adapted to illuminate the target.
13. An image reader as claimed in claim 5 comprising at least one additional aperture aligned between said slit aperture and said cylindrical lens.
14. An image reader as claimed in claim 4 wherein the distance between the lines in each pair remains substantially constant and the lines vary in length as a function of the distance between the reader and the target.
15. An image reader as claimed in claim 1 wherein the pattern components are two pairs of substantially parallel lines wherein one pair of parallel lines is substantially perpendicular to the other pair of parallel lines.
16. An image reader as claimed in claim 15 wherein the first, second, third and fourth optical apparati each comprise:
a targeting illumination source;
an aperture having an elongated slit positioned in front of the illumination source; and
a cylindrical lens positioned in a corresponding orientation in front of the aperture.