Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
  • H04N1/047—Detection, control or error compensation of scanning velocity or position
  • H04N1/053—Detection, control or error compensation of scanning velocity or position in main scanning direction, e.g. synchronisation of line start or picture elements in a line
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
  • G01D5/28—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with deflection of beams of light, e.g. for direct optical indication
  • G01D5/30—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with deflection of beams of light, e.g. for direct optical indication the beams of light being detected by photocells
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
  • G02B7/18—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors
  • G02B7/182—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors
  • G02B7/1821—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors for rotating or oscillating mirrors
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
  • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
  • H04N1/113—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors
  • H04N1/1135—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using oscillating or rotating mirrors for the main-scan only
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/024—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof deleted
  • H04N2201/02406—Arrangements for positioning elements within a head
  • H04N2201/02439—Positioning method
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/04—Scanning arrangements
  • H04N2201/047—Detection, control or error compensation of scanning velocity or position
  • H04N2201/04701—Detection of scanning velocity or position
  • H04N2201/0471—Detection of scanning velocity or position using dedicated detectors
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/04—Scanning arrangements
  • H04N2201/047—Detection, control or error compensation of scanning velocity or position
  • H04N2201/04701—Detection of scanning velocity or position
  • H04N2201/04732—Detecting at infrequent intervals, e.g. once or twice per line for main-scan control
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/04—Scanning arrangements
  • H04N2201/047—Detection, control or error compensation of scanning velocity or position
  • H04N2201/04701—Detection of scanning velocity or position
  • H04N2201/04744—Detection of scanning velocity or position by detecting the scanned beam or a reference beam
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/04—Scanning arrangements
  • H04N2201/047—Detection, control or error compensation of scanning velocity or position
  • H04N2201/04753—Control or error compensation of scanning position or velocity
  • H04N2201/04758—Control or error compensation of scanning position or velocity by controlling the position of the scanned image area
  • H04N2201/04767—Control or error compensation of scanning position or velocity by controlling the position of the scanned image area by controlling the timing of the signals, e.g. by controlling the frequency o phase of the pixel clock
  • H04N2201/04768—Controlling the frequency of the signals
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N2201/00—Indexing scheme relating to scanning, transmission or reproduction of documents or the like, and to details thereof
  • H04N2201/04—Scanning arrangements
  • H04N2201/047—Detection, control or error compensation of scanning velocity or position
  • H04N2201/04753—Control or error compensation of scanning position or velocity
  • H04N2201/04794—Varying the control or compensation during the scan, e.g. using continuous feedback or from line to line

Definitions

• the invention relates to an arrangement and a method for measuring on a resonant oscillator and for its control.
• a resonant oscillator is understood to mean, on the one hand, a plate which can be set in torsional vibrations and is suspended on torsion bands.
• a torsion bar that can be set in torsional vibrations and is clamped on one side is also a resonant oscillator.
• a vibrating functional part a mirror is used in particular, which serves to deflect the light beam. If resonant transducers are used to deflect a light beam, they are also referred to as oscillating mirrors or resonance scanners. Resonant transducers are also used as sensitive sensors. The invention is also provided for this field of application.
• a resonant oscillator has a mechanical natural resonance with which it oscillates with a suitable excitation.
• a drive of the resonant oscillator is expediently coupled to an electronic control device in such a way that a periodically acting force acts on the oscillator at or near the frequency of the mechanical natural resonance.
• a predetermined amplitude of the vibration is to be generated.
• the resonant vibrator is excited by electromagnetic or electrostatic forces.
• piezoelectric forces, gas or liquid flows there are also solutions that use piezoelectric forces, gas or liquid flows.
• the mechanical natural resonance of the resonance scanner is subject to fluctuations.
• the amplitude of the resonance scanner is subject to strong changes when the operating or ambient conditions change.
• resonant oscillators An important area of application for resonant oscillators is the deflection of a light beam, in particular a laser light beam, for example for image generation.
• a moving surface of the transducer is designed to reflect the wavelength of the light beam.
• Intensity modulation of this light bundle is provided for image generation, the modulation for each pixel being synchronized with the current mirror position. It is necessary to define the beginning of the line and to generate a pixel clock.
• US 5,121,138 A1 describes the acquisition of a pixel clock by measuring the instantaneous speed of a resonant oscillating mirror, which is not described in any more detail.
• the pixel clock corresponds to the pixel width and this is proportional to the deflection speed of the mirror surface.
• the same pixel widths and thus the same pixel spacing should be achieved.
• power modulation of the light bundle is proposed, the intensity of the light bundle also being a function of the speed, so that the same image contents are to be displayed at the same brightness regardless of the instantaneous speed of the mirror.
• Rotating mirrors by means of an optical mirror position determination.
• the row of diodes determines the mirror position by deflecting a measuring beam.
• a control value is generated from the comparison of the position of the measuring beam on the diode row with a target position, which is entered into a control circuit that controls the mirror. It is essential that the angular position of the measuring beam on the diode row with a target position, which is entered into a control circuit that controls the mirror. It is essential that the angular position of the measuring beam on the diode row with a target position, which is entered into a control circuit that controls the mirror. It is essential that the angular position of the
• Rotating mirror is adjustable.
• Movement necessarily follows a sin function.
• the position can be measured optically.
• WO 98/13719 A1 uses two piezoelectric sensors which are moved with a resonating oscillating mirror surface. The evaluation of the electrical signals resulting from the torsion due to the movement is evaluated.
• US 3,609,485, US 3,642,344 and US 4,044,283 use electromagnetic detectors to determine the amplitude and phase of the resonant oscillators and to regulate the amplitude.
• the object of the invention is to determine the oscillation frequency, phase position and the maximum amplitude with high accuracy in a resonant oscillator.
• the resonance frequency be as constant as possible in relation to the line frequency of the printer, imagesetter or video standard.
• the time course of the deflection (speed and phase) should be determined with a high resolution and, if necessary, the amplitude should be regulated.
• the beginning of the line of a scanned line should be able to be determined with pixel accuracy.
• a resonant oscillator has a first mirror surface which is deflected about an oscillation axis with a period T by means of a drive unit, a laser diode which is arranged opposite the first mirror surface and which has a measuring beam on the first Emits mirror surface, wherein a beam axis of the measuring beam intersects the oscillation axis and the beam axis is at an angle ⁇ related to the rest position of the first mirror surface of the resonant oscillator.
• a first photo receiver is arranged opposite the first mirror surface at a known distance a from the beam axis of the measuring beam and at a known distance b from the first mirror surface in such a way that the photo receiver lies in a plane which is spanned by a deflected measuring beam and deflected Measuring beam within a quarter of a period (0 .... T / 4 or 0 .... ⁇ / 2) of an oscillation and within a subsequent quarter (T / 4 .... T / 2 or ⁇ / 2. ... ⁇ ) during this period moved over the photo receiver, the photo receiver is connected to an electronic evaluation system, which gains pulses depending on the exposure, this
• Pulses are obtained at times (ti, t 2 ) at which the deflections of the resonant oscillator are outside the maximum of the oscillation (n * 2 ⁇ + ⁇ / 2; n
• the period T of the sinusoidal oscillation is assumed to be known here and regarded as sufficiently constant that the accuracy of the calculated actual value of the amplitude is sufficient for many applications.
• a parallel measuring beam from the laser diode is sufficient for the measurement.
• the laser light is bundled in such a way that a spot sweeps over the detector surface of the photodiode.
• the laser diode can be by another laser or, for example, by a
• Luminescent diode or other light source to be replaced with a suitable one
• the photodiode can be replaced by another photosensitive
• Component e.g. replace a photo transistor or a photo resistor.
• the light-sensitive component delivers a sufficiently accurate and reproducible signal to the evaluation electronics for evaluation.
• the first mirror surface is preferably designed as a flat mirror for the
• Wavelength of the radiation emitted by the laser diode is highly reflective. With the distance b of the photodiode from the mirror surface, the actual value of the amplitude is only exactly calculated if the oscillation axis of the resonant oscillator lies exactly in the mirror surface. Although this is rarely the case in practice and the mirror surface performs a small rotary movement on a circular arc in addition to the angular deflection, it is not necessary to take this offset (thickness of the mirror) into account in the calculation.
• Half the thickness (for example 30 ⁇ m) of the oscillating plate carrying the mirror surface is very small in relation to the distance b to the photodiode (for example 5 cm), so that the resulting error is not relevant in practice.
• the angle ⁇ is preferably in the range between 30 ° and 90 °. If the angle ⁇ is equal to 90 °, a particularly compact structure results.
• An advantageous further development of the invention consists in that a second photo receiver is arranged symmetrically to the first photo receiver in relation to the beam axis of the measuring beam in the plane spanned by the reflected measuring beam. With this arrangement, two equivalent measurement signals are obtained within half a period, which are advantageously used for the calculation and adjustment of the measurement arrangement. This is explained in more detail in the description of the figures.
• the resonant oscillator is used as a mirror for deflecting a useful light beam, it has a second mirror surface which is arranged opposite the first mirror surface.
• the application of the arrangement is not limited to applications that deflect a light beam. Rather, the principle of the invention can be used in general for resonant oscillators, which e.g. can be used as a vibration standard or as a transducer.
• Another advantageous embodiment of the invention is that the incident measuring beam and the deflected measuring beam are at a fixed angle ⁇ to each other, which is orthogonal to the deflection angle ⁇ .
• the invention also includes the use of the actual value of the amplitude for its regulation.
• the evaluation electronics are connected to a control device and this to a drive unit for the resonant oscillator.
• the evaluation electronics are connected to video electronics, which have a computing circuit and memory.
• the video electronics itself is connected to driver electronics and this is connected to a modulatable laser light source that generates the useful light bundle. If the video electronics are controlled with a video signal, the arrangement according to the invention supplies a light beam which is modulated synchronously with the mirror deflection. If the deflected light beam hits a projection surface, an image is written line by line.
• a resonant oscillator is deflected about an oscillation axis with a period T, within each quarter of a half-wave with a predetermined deflection, ⁇ i pulses are determined and times (ti, t 2 ) are determined be, the predetermined deflection outside the maximum of
• the method is based on the principle of a time measurement between at least two function values of the same or different deflection with a known functional course of the deflection movement. If only two function values are measured, the period T must also be measured or calculated or known. The value T / 2 is also sufficient for symmetrical functions.
• the principle described above is applied to the amplitude measurement of a resonant line mirror for a video projection system, in that the time difference ⁇ t between at least two known ones. Points of equal deflection and the period T of the vibration can be determined.
• the invention further relates to the use of the measured actual value of the amplitude for controlling or regulating the amplitude.
• the actual value of the amplitude is fed to a control device for setting a target value of the amplitude of the resonant oscillator.
• the control device controls the drive unit.
• the amplitude can be regulated by a change in voltage, a change in current, by a change in a duty cycle or by a change in frequency.
• the angle ⁇ arctan a b is dimensioned such that the time period ⁇ t which is calculated corresponds to a line dead time when writing successive lines of an image.
• “Corresponds” here means that the time period is equal to the line dead time of a video standard or another standard. However, the time period ⁇ t can also deviate positively or negatively from a standardized dead time if it is ensured that the line has the desired width with all the pixels of this This usually requires the use of a memory for the video data in order to decouple incoming video data and outgoing video data in time.
• the application of the invention is not restricted to the systems mentioned, but rather the invention can be transferred to other technical fields in which a resonant transducer is used, for example image acquisition, radar, measurement technology, measurement technology. In one of the applications mentioned in ll. and / or in the fourth quadrant one pulse at a time (t 2 , t, t 6 ,) within the periodicity of the
• Vibration obtained which provides the start of writing the first pixel of a line and the last pixel of a subsequent line, for example for a video image or for a printer.
• a control signal for modulating a deflected light beam and values for correcting the pixel clock are determined from the speed curve. This also controls the pixel width. These measures are necessary in order to correct the image geometrically and to obtain a high image resolution and uniformly bright lines.
• FIG. 1 measuring arrangement with a photo receiver
• FIG. 2 movement function of the resonant oscillator with information on the measuring arrangement according to FIG. 1,
• Fig. 6 movement function and speed function of the resonant vibrator with a basic representation of the
• Fig. 7 View of an arrangement with a laser diode and two
• Fig. 8 side view of an arrangement with a laser diode and two
• Fig. 9 top view of an arrangement with a laser diode and two
• the resonant oscillator is a mirror 1 with two opposite, parallel and flat mirror surfaces 8 and 9.
• the mirror 1 carries out a sin-shaped oscillation.
• its excitation can be electromagnetic or electrostatic. It can be suspended, for example, on tensioning straps or on a torsion bar, which form an oscillation axis 2.
• a measuring beam 3 of a laser diode 4 is directed onto a first mirror surface 8 of the mirror 1.
• the direction of the measuring beam 3 is identical to a surface normal of the mirror 1 in its rest position, the surface normal intersecting the oscillation axis 2 of the mirror 1.
• a photo receiver 6 is arranged at a distance from the laser diode 4.
• the choice of the size of the deflection at which measurement is carried out can lie between the rest position and the amplitude, these two values and their immediate surroundings not being permissible or not suitable for a measurement.
• the size of the deflection at which measurement is carried out is made in particular according to one of the following criteria: a) deflection at which a minimal measurement error occurs taking other boundary conditions into account, or b) ⁇ t corresponds to the line dead time of a video standard or c) value, which limits a range in which the linearity error does not exceed a certain size.
• the values are measured in successive I. quadrants of the sin-shaped oscillation.
• the arrangement according to FIG. 1 is also intended to determine the usable scanning angle in a resonant oscillator which is used as a line mirror.
• the distance a in FIG. 1 is dimensioned such that measurements are made on the resonant oscillating mirror with a deflection of 80% of the amplitude
• the dead time lies in this angular range, which is then 41%; 59% of the time is used to write the line. With a dead time of 20%, there is an angular ratio used for writing the line
• the deflection angle ⁇ 2
• is calculated. While the mirror is performing an oscillation period T, it passes through the unit circle from 0 to 2 ⁇ .
• the time difference ⁇ t A is the same in relation to the period T
• ⁇ t is based on the unit circle 2 (t A ) ⁇ 2 ⁇ (1) with 2 ( ⁇ t A ) angle in rad, which was covered in the time difference ⁇ t A on the unit circle.
• each angle Z (t x ) on the unit circle at time t x is assigned a deflection angle ⁇ x .
• the deflection angle ßi is assigned to the angle 2 (t, 2, 3 ) on the unit circle for the subsequent calculation.
• ßmax is the positive amplitude of the resonant oscillator (in the positive half-wave).
• the measurement and calculation described applies to the first and second quadrants of the sin-shaped movement function of the resonant oscillator, the first half-wave.
• Ißmaxp r ßmaxl where - ßmax is the negative amplitude of the resonant oscillator in the third and fourth quadrants (in the negative half-wave).
• ⁇ Ißmaxl +
• Time difference ⁇ t A i.e. the measurement of ti and t 2
• the period T In a practical application, it is usually necessary to measure the period T, since this cannot be regarded as constant in the case of a resonant mirror. For example, temperature fluctuations change the resonance frequency, so that the drive frequency of the mirror has to be tracked in order to keep the amplitude constant.
• the period results from the measurements of the time ti in the 1st quadrant of one period and the time t 3 in the 1st quadrant of the following period and the calculation of where t. 3 is the time with the deflection ⁇ i in the period that follows the time t i.
• the beam direction of the measurement beam 3 must exactly match a surface normal in the rest position of the mirror surface of the resonant oscillator in order to avoid additional measurement errors.
• FIG. 3 shows a measuring arrangement in which both half periods of the resonant oscillator are used to deflect the measuring beam 3.
• the arrangement according to FIG. 1 is supplemented by a further, second photo receiver 7, which detects the negative half-wave of the resonant oscillation.
• the second photo receiver 7 is also arranged at a distance b from the mirror 1, but at a distance -a from the measuring beam 3 of the laser diode 4.
• FIG. 4 shows, in analogy to FIG. 2, a representation of the sin-shaped oscillation with the corresponding measured values. Analogous to the derivation carried out for FIGS. 1 and 2
• the symmetry is achieved when the measured time differences ⁇ t A and ⁇ t ß are the same.
• a tried and tested arrangement that deflects a measuring beam to write a line has the following parameters:
• FIG. 5 shows an arrangement with a resonant oscillating mirror for line deflection in a video projection system in a simplified overview.
• the arrangement consists of a control circuit for a drive 14 of the resonant oscillating mirror 1 and a video signal processing which converts the electrical signal VIDEOin into an optical signal of a light beam 19 and assigns the instantaneous angular position ⁇ of the mirror 1.
• the phase locked loop is formed from the transducer according to the invention, consisting of the laser diode 4, the photodiodes 6 and 7 and the evaluation electronics as well as a control device 12, a mirror drive 14, the first mirror surface of the mirror 1 and the reflected measuring beam 5.
• the video signal processing includes video electronics 13, a driver electronics 15 and a modulatable laser source 16.
• the video electronics 13 in turn consists of the main assemblies arithmetic circuit 17 and memory 18.
• the evaluation electronics 11 of the transducer delivers the instantaneous amplitude ⁇ s ⁇ and an internal synchronization signal HSYNCint for the horizontal deflection from the time measurements.
• the size of the instantaneous amplitude ⁇ j St becomes
• Control device 12 supplied.
• the signal HSYNCint is fed to the arithmetic circuit 17 of the video electronics 13.
• the arithmetic circuit 17 calculates the associated value dt for each value dß from the time measurements ti, t 2 , t3 and with the presence of the sin-shaped movement behavior of the mirror.
• ⁇ ß is determined for dß, for example, the angle ⁇ ß is the width of a pixel (or a part thereof) and the associated value for ⁇ t is calculated.
• the calculated values ⁇ t are used for the asynchronous reading of the video data VIDEOin temporarily stored in the memory 18.
• the video data VIDEOin which is linearly read in and stored in time in the memory 18 with an input synchronization signal SYNCin are controlled by the arithmetic circuit 17, read out in a non-linear manner in time in accordance with the calculated values ⁇ t and transferred to the driver electronics 15 as data VIDEOout.
• the driver electronics 15 controls the modulatable laser light source 16, which emits the modulated useful light beam 19 onto the second mirror surface 9.
• the driver electronics 15 controls the modulatable laser light source 16, which emits the modulated useful light beam 19 onto the second mirror surface 9.
• a geometrically linear line with a deflected useful light beam 20 is shown.
• the sin-shaped behavior of the mirror is thus compensated for with the electronic control.
• the pixel clock first decreases with increasing pixel numbers 1, 2, 3, ... up to the middle of the line and then rises again until the last pixel n of the line; the pixel clock is proportional to the speed of the mirror. It is also essential that the memory 18 is organized and the video data is read out in such a way that the pixels of a first line in the sequence 1, 2, 3, .... n-2, n-1, n and in a second half period the pixels of a subsequent line in the
• Pieces of curve symbolize the section for writing the lines.
• Fig. 7 shows a side view of the measuring arrangement consisting of the laser diode 4 and the photodiodes 6 and 7, which are attached to a carrier 10.
• the photodiodes 6 and 7 lie in one plane, the laser diode is offset by an amount h from this plane.
• the amount h is expediently chosen to be so large that the reflected measuring beam does not irradiate the laser diode in order to avoid impairing the operation of the laser diode.
• FIG. 8 shows another side view of the measuring arrangement.
• Fig. 9 shows a plan view of the measuring arrangement in section AA. It can be seen here that a lens is arranged in the beam path of the laser diode, which focuses the reflected measuring beam in a plane in which the photodiodes 6 and 7 are arranged.
• FIG. 10 shows a measuring arrangement corresponding to FIG. 3, in which the angle ⁇ between the beam axis 21 of the measuring beam 3 and the rest position of the first mirror surface 8 is 60 °. Accordingly, the angle ⁇ 'is also 60 °.
• the photo receivers 6 and 7 are also arranged symmetrically to the beam axis 21 at a distance a and at a distance b from the oscillation axis 2. With this arrangement, no back reflection can get into the laser diode 4, even if the beams are not inclined, the angle ⁇ is zero (in comparison, the angle ⁇ > 0 is shown in FIG. 8).
• the inclination of the laser diode 4 and the photoreceiver 6 and 7 reduces the overall depth of the arrangement.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Multimedia (AREA)
• Signal Processing (AREA)
• Optics & Photonics (AREA)
• Mechanical Optical Scanning Systems (AREA)
• Facsimile Scanning Arrangements (AREA)
• Length Measuring Devices By Optical Means (AREA)
• Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

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• 2002
  • 2002-02-08 DE DE10205207A patent/DE10205207B4/de not_active Expired - Fee Related
• 2003
  • 2003-02-07 JP JP2003566785A patent/JP2005517212A/ja active Pending
  • 2003-02-07 EP EP03706457A patent/EP1472643B1/de not_active Expired - Lifetime
  • 2003-02-07 AU AU2003208816A patent/AU2003208816A1/en not_active Abandoned
  • 2003-02-07 WO PCT/EP2003/001242 patent/WO2003067509A1/de not_active Ceased

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