Compact aiming light assembly and imaging module for, and method of, generating an aiming light spot with increased brightness and uniformity from a light-emitting diode over an extended working distance range in an imaging reader

An imaging module in a reader for electro-optically reading targets by image capture over a range of working distances, the imaging module comprising:

• a printed circuit board (PCB);
• an illumination light assembly mounted on the PCB for illuminating a target;
• an imaging assembly having a solid-state imager with an array of image sensors mounted on the PCB, and an imaging lens for capturing return light over an imaging field of view (FOV) from the illuminated target, and for projecting the captured return light onto the array;
• and
• an aiming light assembly mounted on the PCB, for generating at least one aiming light spot with increased brightness and uniformity over the range of working distances on the target prior to illuminating and reading the target, the aiming light assembly including a light emitting diode (LED) for emitting an aiming light beam, a field stop through which the aiming light beam passes, the field stop being in close confronting relationship with the LED, an aiming lens having a lens aperture and an optical axis, the aiming lens being spaced along the optical axis away from the field stop and being operative for optically modifying the aiming light beam passing through the field stop to form the at least one aiming light spot over the range of working distances, and a field lens located in the vicinity of the field stop and spaced along the optical axis away from the LED, the field lens being operative for imaging the LED downstream to the vicinity of the lens aperture of the aiming lens.

A method of generating at least one aiming light spot with increased brightness and uniformity over a range of working distances in which targets are electro-optically read by image capture, the method comprising:

• emitting an aiming light beam from a light emitting diode (LED);
• passing the aiming light beam through a field stop that is in close confronting relationship with the LED;
• optically modifying the aiming light beam passing through the field stop to form the at least one aiming light spot over the range of working distances by spacing an aiming lens, which has a lens aperture and an optical axis, away from the field stop along the optical axis;
• and
• imaging the LED downstream to the vicinity of the lens aperture of the aiming lens by locating a field lens in the vicinity of the field stop and spaced away from the LED along the optical axis.