Abstract: This invention is intended to contribute to improvements of the reading accuracy of a bar code reader and performance of a POS system or the like. To attain this object, according to the invention, when one of the data blocks constituting a bar code cannot be detected, addresses of the non-detected data block are determined based on a width of the detected data block and addresses of the center bar. The invention is constituted such that data of the previously non-detected data block is detected based on its addresses.

Abstract: The present invention relates to a semiconductor laser control method used preferably for a reading control system such as a bar code reading device and to a semiconductor laser control device employing the above method. The object of the invention is to provide a semiconductor laser control device which can be controlled based on the output of a semiconductor laser, provides a stable laser output in a noise environment, enables easy output adjustment, and is immune to external thermal or electrical noises. In the semiconductor laser control method where the light amount of a light amount to current controllable semiconductor laser is subjected to a feedback control with a predetermined time constant while it is monitored, when the light amount is less than a predetermined value, the semiconductor laser is subjected to an feedback control with a first time constant. When the light amount is more than a predetermined value, the semiconductor laser is subjected to a feedback control with a second time constant.

Abstract: An apparatus for demodulating bar codes is disclosed. In this apparatus of this invention, a distortion quantity calculation unit for calculates a distortion quantity of a bar width of a character to be demodulated by use of bar code data generated by reading the bar codes in which characters are expressed by bar widths. A distortion quantity determining unit determines whether or not a bar width distortion quantity calculated by the distortion quantity calculation unit falls within a range of predetermined values. A first demodulation unit, when determining that the distortion quantity of the bar width falls within the range of the predetermined values, demodulates the character from the bar code data by effecting a first correcting process on the bar width distortion quantity.

Abstract: The present invention relates to an ambient light detector, a laser lighting control device using the same suitable for a bar code reader, and a bar code reader. The object is to require no explanation on a special operation and to realize an easy device design and a low manufacturing cost. Each device includes an ambient light detector to detect light around a peripheral device, and judging device to provide a signal indicating that an ambient light detected by the ambient light detector has exceeded a predetermined value over a predetermined time.

Abstract: A bar code reader using a high speed scanner, containing: a scanning unit scanning a surface on which a bar code is printed; a bar width detecting unit successively detecting widths of bars; a bar width storing unit storing the widths; an address generating unit generating an address of the bar width storing unit at which each of the widths is to be stored; a fast screening unit determining whether a set of widths successively detected by the bar width detecting unit satisfies a predetermined condition for the set of widths constituting a complete bar code; and a bar code decoding unit reading a set of successive widths from the generated address, and decoding the bar code determined by the complete bar code detecting unit. A type of bar code detecting unit detecting a type of bar code constituted by the detected widths, and an address & type storing unit storing the detected type of bar code, together with information on the generated addresses for the widths of the bar code, may be inserted.

Abstract: The present invention relates to a bar code reading method and a bar code reader applied preferably to POS systems used in the distribution industry. The object of the invention is to achieve an improved reading ratio or a reduced erroneous reading ratio in practical use by evaluating quantitatively the reliability of demodulation data and by performing a coincidence checking plural times only when a large error is recognized. When a reading distortion amount measured is within a predetermined allowable value, data extracted and demodulated from the bar code is judged to be valid, whereby the bar code reading is completed. When a reading distortion amount measured is not within the predetermined allowable value, if the same data from the bar code is extracted and demodulated continuously and at least twice, the same data extracted and demodulated from the bar code is judged to be valid, whereby the bar code reading is completed.

Abstract: A semiconductor laser driving circuit has a semiconductor laser for emitting a laser beam according to a drive power. A photodetector is provided for effecting photo-electric conversion of the laser beam to output a corresponding electric signal. A monitoring circuit is connected for monitoring the electric signal to output a monitor signal indicative of variation in intensity of the laser beam. A controlling circuit is connected for comparing the monitor signal with a given reference signal to output a control signal according to difference therebetween. A powering circuit 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 different from the reference signal to detect abnormality to output an abnormality signal.

Abstract: An article detection device includes: a light emission unit for emitting a detection light for irradiation onto an article, and a light reception unit for receiving a light reflected from the article. The article detection device also includes; an analog-to-digital converter for converting the reflected light to a digital signal, a first register for storing the digital signal after being sampled using a first sampling signal having a first period, and a second register for storing the digital signal after being sampled using a second sampling signal having a second period shorter than the first period.