Abstract: A scan velocity detector for detecting scan velocity when a surface of an object is scanned with a beam of light generated by a light-projecting element; the scan velocity detector comprising light-receiving element to receive light which is reflected, threshold-level setting element for setting threshold levels, delay element for delaying the output of the light-receiving element and counting element for counting the time from when the output of the delay element exceeds a certain threshold level until it reaches a different threshold level; the scan velocity detector being an integral part of a bar code scanner, or similar device.

Abstract: In the white level detection circuit for an optical image reader, for a low value portion in an image, the white level signal corresponding to an image signal of a high value background portion which precedes to the low value portion is held steady. Accordingly, even if the low value image portion has a long duration, the white level signal may be kept at a proper value for the image signal corresponding to the low value image signal. For the high value background portion, the white level signal that immediately follows a variation of the image signal can be obtained. Therefore, a proper white level signal can be generated for the background portion. Various processing applied to the image signal on the basis of the white level signal may be performed in a satisfactory manner. As a consequence, the read performance of the optical image reader may be remarkably improved.

Abstract: An automatic gain control (AGC) circuit for use in an optical code reader which eliminates error caused when regular reflecting light is directly incident on the detector element of the optical code reader. The AGC has a variable gain amplifier which receives a signal from the detection element and outputs a signal to a peak-holding circuit. The output from the peak-holding circuit is used to control the gain of the variable gain amplifier. A reset circuit resets the output of the peak-holding circuit either when the output reaches a predetermined level, or at regular intervals during the operation of the optical code reader. The output of the variable gain amplifier is fed to a binary circuit.

Abstract: A bar-code reading apparatus in which a bar-code is scanned and processed for recognition of the bar-code on the basis of the scanning comprises scanning signal storage means for storing scanning signals which are obtained by scanning the bar-code and which correspond to bars and/or spaces scanned in at least two successive scannings. A counter counts the number of bars and/or spaces scanned in each scanning, while a number-of-bars storage means stores count values of the counter means in at least two successive scannings. A first comparison means compares the respective count values of the counter means in the last two scannings stored in the number-of-bars storage means with each other and generates an enabling signal when the count value in the last scanning is not larger than that in the preceding scanning.

Abstract: A bar code reader reads a bar code by scanning a laser beam on a screen on which the bar code is displayed. The bar code reader has a beam scanning device for scanning the laser beam irradiated from a laser oscillator. The beam scanning device has a polygon mirror which is rotated and driven around an axis. The polygon mirror forms at least two kinds of flat reflecting surfaces for respectively scanning the laser beam along with the rotation of polygon mirror. Scanning angles by the reflecting surfaces are twice as large as opposite angles to which the reflecting surfaces correspond respectively. The laser beam is scanned at two or more kinds of scanning angles, that is, scanning angles and which are respectively adapted to the long and short bar codes. Therefore, the bar code can be accurately read irrespective of a length thereof.

Abstract: A symbol reader for reading symbols on a symbol surface. An optical system including a laser, condensing lens and scanning mirror illuminate a symbol surface to be read with a laser beam, scanning across the symbol surface. A transducer measures the amount of light reflected from the symbol surface. A differentiating circuit develops a differential coefficient indicative of the change of light intensity as light scans the symbols being read. A control system adjusts the optical system illuminating the symbol surface so as to maximize the differential coefficient, thereby minimizing the diameter of the light beam to allow for adequate reading of the symbol surface at variable distances.

Abstract: A mark reading device that reads marks such as a bar code, or the like on a remote surface. A laser beam is outputted, deflected through a scan angle and the reflected energy is read at a detector. This energy is processed and converted to a usable format for input into a computer, cash register, or any type of data collection device. The present invention improves depth of field and readability by varying the output energy of the laser after each successive scan, thus providing a range of energy levels at the detector.

Abstract: A laser waveguide is developed which uses various combinations of convex and concave mirrors in conjugate pairs. The waveguide is made more effications by arranging the mirrors and selecting the reflective surfaces thereof so that the diametral increase of plurality of parallel light beams is checked, or the diameter reduced.

Abstract: A laser knife is provided with a mechanism by which a plurality of specialized hand pieces may be detachably coupled to the front end portion of the optical fiber light path for the laser.

Abstract: A laser scalpel in which optical fiber is used as the optical wave guide and the optical fiber is guided from a laser main body housing a laser source therein to the areas to be irradiated along a shore means provided on the laser main body is disclosed. The optical fiber is provided with a hand piece on the exterior of the forward end portion. The hand piece is so constructed that it facilitates the directing of the forward end of the fiber toward the areas to be irradiated. A supporting wire means is provided along the shore means so as to be axially movable. The forward end of the wire means is connected to the hand piece and the rear end of the wire means is connected to a balancing means for counter-balancing at least the weight of said hand piece.

Abstract: A leakage current detector includes conductive inner and outer housing structures separated by an insulator, with the circuit or equipment under observation being disposed within the inner housing. A current detecting circuit connects the two housings and measures the current therebetween.

Abstract: A monitor device for use in a laser system transmitting laser light through an optical fiber includes a heat-sensitive element which produces an output to monitor the laser system, the element being provided in a predetermined area of the fiber.

Abstract: The grounding of an electrical apparatus is monitored by a primary circuit which is inductively coupled to a coil connected in series between the grounding line of the power cord and a grounding terminal on the electrical apparatus to which a second grounding line is connected.

Abstract: Signals for controlling the discharge current and laser gas pressure are provided in predetermined combination in accordance with a selected laser output level.