| 摘要 |
An optical reader circuit has an adaptive exposure control comprising at least one exposure control pixel 352 or 608 distinct from a plurality of imaging pixels in a imaging array e.g. 607. The output from the control pixel(s) is compared in a comparator 360 with a threshold signal 361 and used to change a clock signal to vary the exposure time of the array pixels, depending on ambient light levels. Preferably, each imaging pixel is individually controlled by varying the reset time. Preferably, the imaging array has a common output bus and may have a grid or star pattern array (Figs 2-5). Preferably the optical reader is embodied in a bar-code reader and made from CMOS technology including integrating the signal processing circuits on the same chip. |
