Laser Doppler Velocity Sensor Introduction Features Specifications Theory/Applications Brochure Download Where to Buy Support View: Diagrams Output Connector pin number and function Chart External Dimentions Example for Speed Deviation Detection Optical Sensor Installation Method Diagram Measuring with a High Reflectivity Object Diagram Movie Theory OTHER LASER DOPPLER VELOCITY SENSOR LV-20Z/LV-50Z LASER DOPPLER VELOCITY SENSOR VIDEO To download the images Right click on Download Link and Save Target As to your local folder. DOWNLOAD

INTRODUCTION High-Precision, Compact, Low Cost, Next Generation of Non Contact Laser Doppler Velocimeters Canon laser Doppler velocimeters, equipped with diffraction gratings, take advantage of an optical system (diffraction laser light Doppler method) that will not dependent on the laser wavelength. Therefore, the measurement precision is unaffected by fluctuations in the semiconductor laser wavelength due to changes intemperature. Not only are these sensors environmental stability they can be used for a wide variety of applications; since we use an E/O frequency shifter, they are capable of taking measurement from a still as well as a running state. FEATURES Since the unit is of non-contact type, measurement can be taken even with velocity irregularities, and it does not place any extra load on the object whose velocity is being measured. By Canon’s original diffraction laser-light Doppler system, the sensor unit is ultra-compact with high precision. The E/O frequency shifter enables the unit to measure velocities varying from -200 to 2,000mm/sec (LV-20Z). THEORY The laser light emitted by a semiconductor laser is positioned so that it is a linearly polarized beam with respect to the z-axis. Then, a collimator lens makes it into a parallel light beam. The grating array direction of this parallel light beam is the direction of the y-axis, and the diffraction grating with a grating pitch d divides the beam into two light beams by a diffraction angle of q. Here, the equation d sin θ = λ holds. These two light beams pass through a first lens and are then irradiated into an E/O frequency shifter consisting of electro-optical crystals. After that, they are diffracted by a second lens before irradiated to the object moving at a velocity of V, which is being measured. The incidence angle of the two irradiated light beams is θ. The first and second lenses form an afocal optical system with a magnification of m, and the aberration is corrected so that sin θ / sin θ = m. The two light beams that are now modified to have a frequency difference fR by the E/O frequency shifter are then irradiated to the object to be measured, and the diffused beams coming back from the object proceed through the second lens and a condensing lens, eventually reaching the photo diode. The beat signal (i.e., the Doppler frequency) of these light beams containing the speed information obtained here is F=2V/md+fR, independent of the laser frequency; in addition, it is possible to measure the velocity from an object that is originally in a still state. By signal-processing this Doppler frequency, the unit displays the velocity and sends the F/V output and pulse output. APPLICATION EXAMPLES OA Equipment ·Detection of the speed of copying paper & speed irregularities ·Detection of rotation irregularities of photo-conductor drums ·Detection of the displacement of printer paper AV Equipment ·Detection of speed irregularities of magnetic tapes ·Detection of rotation irregularities of magnetic heads for Office Automation machine Rotation/motion speed detection and speed deviation detection of; - Paper feeding - Sensitivity drum - Belt and gear for Audio Visual machine Rotation/motion speed detection and speed deviation detection of; - Recording tape - Rotary head for Factory equipment Rotation/motion speed detection and speed deviation detection of; - Machine tools - Printing machine for Producing spot Conveyer speed detection or length measurement of; - Steel sheet - Processed goods (paper, film, cable, etc) SENSOR INSTALLATION METHOD 1. The measuring accuracy according to the installation is not influenced by the angle a shown in following figure. 2. The angle β causes an error of 1-cos β. 3. The deviation angle between the bottom surface and the movement direction causes an error of 1-cos γ. 4. When the bottom surface and the positioning holes are used as reference 5. Install positioning pins as shown in the figure in the mounting surface set up parallel to the speed direction. After positioning with the positioning holes in the bottom surface of the body, fix the body with screws.” 6. Pay attention to the angle β and γ, use the bottom surface and the positioning holes as reference for installation. SPECIFICATIONS LV-20Z LV-50Z Optical sensor S-100Z Signal Processing unit P-20Z P-50Z Measurement Range - 200 to 2000 mm / sec. - 50 to 5000 mm / sec. Maximum Resolution 2.5 µm / pulse 5 µm / pulse Focal Length 40 mm Depth of focus ± 5 mm Laser spot size 2.4 x 0.1 mm (at focal point) Velocity fluctuation response frequency 0 to 300 Hz Effective object surface Reflectance 20 % or more, flat scattered Output Signal 1 : F/ V analog output - 4 to + 5 V (at RANGE 4 ) - 0.6 to + 7.5 V (at RANGE 4 ) Accuracy less than ± 1 % of full scale 2 : A,B phase balanced output 2.5, 5, 10, 20, 40, 80, 160, 320 µm 5, 10, 20, 40, 80, 160, 320, 640 µm Phase difference 90 ± 30 deg 3 : Doppler pulse output 120 to 1000 kHz 180 to 2200 kHz Measurement Certainty <100 mm / sec : ± 0.2 mm / sec, > 100 mm / sec : ± 0.2 % 4 : Optical shift frequency output 200 kHz, CMOS level 5 : UP/DOWN pulse output pulse per Δd moving to positive/negative direction 6 : Measurement error output Indicate high level when error Velocity display 5 digit (mm / sec, m / min. selectable) Light source Semiconductor laser ( 680 nm) Voltage 100 ~ 240 V External dimensions Optical sensor 33 x 98 x 39 mm Main unit 235 x 290 x 115 mm Ambient conditions Operating Temperature 0 to 45 ºC Storage Temperature - 30 to 60 ºC Humidity 80 % RH or less (no condensation)