Data symbol reader utilizing ambient light illumination

摘要: A casing, including a grip portion and head portion, houses pair of light sources for illumination, an image sensing device, optical system forming on the photosensor detecting luminance symbol reading area, signal processing circuit, quantity detection circuit. The housing extends from towards area. An ambient window is provided in introducing into source driving circuit controls amount emitted by source, increasing or decreasing light, such that combined illumination between predetermined levels. selector selecting first mode, which maximum decreased to upper limit acceptable range, second minimum increased lower range.