| 摘要 |
<p>PURPOSE: To improve the reliability of a laser scanner for reading a bar code symbol by increasing the small amplitude of high frequency component of an analog signal while using a reinforcing means in order to reinforce the modulation of the analog signal. CONSTITUTION: This device is provided with light guiding means 33 and 34 for guiding light to a display in order to reflect the light, a means 19b for scanning the display along a scanning direction with sampling aperture larger than the width of one narrow element at least having a dimension along the scanning direction, a detecting means 17 for generating a modulation degraded analog electric signal having the high frequency component of small amplitude corresponding to a narrow element and the low frequency component of large amplitude corresponding to a wide element by detecting the beams having various values of strength reflected from the display along the scanning direction, and the reinforcing means for converting that signal to a modulation reinforced analog electric signal having the low frequency component and high frequency component mutually making much closer the values of large and small amplitudes by amplifying the modulation degraded electric signal. Thus, the modulation degraded analog signal can be read well and the reliability of the scanner can be improved.</p> |
