摘要:
A semiconductor laser driving circuit has a semiconductor laser (1) for emitting a laser beam according to a drive power. A photodetector (1b) is provided for effecting photo-electric conversion of the laser beam to output a corresponding electric signal. A monitoring circuit (101) is connected for monitoring the electric signal to output a monitor signal indicative of variation in intensity of the laser beam. A controlling signal (102) is connected for comparing the monitor signal with a given reference signal to output a control signal according to difference therebetween. A powering circuit (103) is operative according to the control signal to apply to the semiconductor laser a drive power effective to eliminate the difference. An abnormality detecting circuit is provided for comparing the monitor signal with a given limit signal which is set defferent from the reference signal to detect any abnormality and output a corresponding signal.
摘要:
In a compact type bar code reader for detecting a bar code symbol provided on a surface of an article, the bar code reader includes: a laser beam generation unit for generating the laser beam to be irradiated onto a bar code symbol; a focus unit for determining a focus of the laser beam; a scanning pattern forming unit (6) for forming various scanning patterns of the laser beam; a light reflection unit for reflecting the laser beam to and from the bar code symbol; a light collection unit (9) for collecting the laser beam reflected from the bar code symbol; and a light reception unit (10) for receiving the laser beam collected by the light collection unit (9), and converting it to an electrical signal; an arrangement of the above units in a casing (11) comprising; the laser beam generation unit, the focus unit, the light collection unit (9), and the light reception unit (10) being arranged at a lower portion of the casing (11); and the scanning pattern forming unit (6) and the reflection mirror (8) being arranged at the upper portion of the casing (11); whereby, a light path of the laser beam is formed in such a way that an emitted light path from the laser beam generation unit to the bar code symbol becomes long, and a reflected light path from the bar code symbol to the light reception unit (10) becomes shorter than the emitted light path.
摘要:
A semiconductor laser driving circuit has a semiconductor laser (1) for emitting a laser beam according to a drive power. A photodetector (1b) is provided for effecting photo-electric conversion of the laser beam to output a corresponding electric signal. A monitoring circuit (101) is connected for monitoring the electric signal to output a monitor signal indicative of variation in intensity of the laser beam. A controlling signal (102) is connected for comparing the monitor signal with a given reference signal to output a control signal according to difference therebetween. A powering circuit (103) is operative according to the control signal to apply to the semiconductor laser a drive power effective to eliminate the difference. An abnormality detecting circuit is provided for comparing the monitor signal with a given limit signal which is set defferent from the reference signal to detect any abnormality and output a corresponding signal.
摘要:
An article detection device includes: a light emission unit (1) for emitting a detection light (DL) for irradiation onto an article; a light reception unit (2) for receiving a light (RL) reflected from the article; an analog-to-digital converter (3) for converting the reflected light to a digital signal; a first register (4a) for storing the digital signal after being sampled using a first sampling signal having a first period; a second register (4b) for storing the digital signal after being sampled using a second sampling signal having a second period shorter than the first period; and a control unit (5) for generating the first and second sampling signals to be sent to the first and second registers, reading the digital signal stored in the first and second registers, calculating a difference between the digital signals in the first register and second register, comparing an absolute value of the difference with a predetermined threshold value, and detecting the article when the absolute value is larger than the threshold value.