Principle and fault exclusion laser scanner (I)
Crystal
2015-12-02 14:45:42
we tend to think that the price of the scanner is not high is a low-tech product, it is not true, do not look at a small scanner, its structure and working principle as much as a large printing equipment. The following specific about its principles and common faults:
The principle of laser scanner when the user touches the power switch or corresponding apparatus allows the scanner after power, VLD issued a red laser beam passes through the beam expander lens is expanded beam onto the mirror surface reflection can swing to the formation of a bar code laser spot. When the mirror swings occur based on the position of the laser spot on the optical reflection principle barcode changes, continuous oscillating mirror, then we will see a red laser line on the bar code, which is due to the phenomenon of persistence of vision. Barcode surface is rough, according to the bar code laser spot is reflected, the bars and spaces of reflection intensity is different, diffuse light incident on the mirror, and then reflected by the mirror to the collector, the collector a light, filtered by the filter natural light into the stray photodiode generates photoelectric sensor signal, and then amplified, plastic decoded into useful information, transmitted to the host.
Unable to read Cause and Remedy
1) did not open this bar code reading function.
2) bar code does not comply with specifications, such as the lack of the necessary blank area, bar and air low in contrast, the proportion of the width of the bars and spaces on the inappropriate.
3) direct sunlight, photosensitive device into the saturated zone.
4) bar code surface covered with a transparent material, reflective too high, although the eye can see the bar code, but reading acquisition strict conditions, can not be read.
The principle of laser scanner when the user touches the power switch or corresponding apparatus allows the scanner after power, VLD issued a red laser beam passes through the beam expander lens is expanded beam onto the mirror surface reflection can swing to the formation of a bar code laser spot. When the mirror swings occur based on the position of the laser spot on the optical reflection principle barcode changes, continuous oscillating mirror, then we will see a red laser line on the bar code, which is due to the phenomenon of persistence of vision. Barcode surface is rough, according to the bar code laser spot is reflected, the bars and spaces of reflection intensity is different, diffuse light incident on the mirror, and then reflected by the mirror to the collector, the collector a light, filtered by the filter natural light into the stray photodiode generates photoelectric sensor signal, and then amplified, plastic decoded into useful information, transmitted to the host.
Unable to read Cause and Remedy
1) did not open this bar code reading function.
2) bar code does not comply with specifications, such as the lack of the necessary blank area, bar and air low in contrast, the proportion of the width of the bars and spaces on the inappropriate.
3) direct sunlight, photosensitive device into the saturated zone.
4) bar code surface covered with a transparent material, reflective too high, although the eye can see the bar code, but reading acquisition strict conditions, can not be read.