Apparatus for and method of electro-optically reading a target in the presence of ambient light by detecting and suppressing the ambient light

A detector assembly for detecting return laser light from a target in the presence of ambient light, and for converting the detected return laser light into an analog electrical information signal bearing information related to the target, and for concomitantly detecting the ambient light, and for converting the detected ambient light into an analog electrical ambient light signal, the detector assembly comprising:

• a first photodetector having a first field of view and a first light collection area;
• a second photodetector having a second field of view and a second light collection area in close proximity to the first light collection area;
• a detector lens spaced from the first and second photodetectors and operative for focusing and directing the return laser light substantially onto the first light collection area over the first field of view;
• wherein the first light collection area is operative for generating a first analog electrical output signal comprised of the information signal and the ambient light signal;
• and
• wherein the second light collection area is operative for generating a second analog electrical output signal substantially comprised of the ambient light signal.

A method of electro-optically reading a target in the presence of ambient light to be suppressed, comprising:

• emitting a laser beam from a laser;
• scanning the laser beam across the target for reflection and scattering therefrom as return laser light;
• detecting the return laser light from the target;
• converting the detected return laser light into an analog electrical information signal bearing information related to the target;
• concomitantly detecting the ambient light;
• converting the detected ambient light into an analog electrical ambient light signal;
• generating a first analog electrical output signal comprised of the information signal and the ambient light signal from a first photodetector having a first field of view and a first light collection area;
• generating a second analog electrical output signal substantially comprised of the ambient light signal from a second photodetector having a second field of view and a second light collection area in close proximity to the first light collection area;
• focusing and directing the return laser light substantially onto the first light collection area over the first field of view;
• processing the first and second output signals to determine a magnitude of the ambient light signal;
• and
• suppressing the ambient light signal when the determined magnitude of the ambient light signal at least equals a threshold.