WO2005116721A1 - Dispositif de balayage laser anamorphique - Google Patents

Dispositif de balayage laser anamorphique Download PDF

Info

Publication number
WO2005116721A1
WO2005116721A1 PCT/EP2004/005726 EP2004005726W WO2005116721A1 WO 2005116721 A1 WO2005116721 A1 WO 2005116721A1 EP 2004005726 W EP2004005726 W EP 2004005726W WO 2005116721 A1 WO2005116721 A1 WO 2005116721A1
Authority
WO
WIPO (PCT)
Prior art keywords
scanning device
laser scanning
anamorphic
speed
writing
Prior art date
Application number
PCT/EP2004/005726
Other languages
English (en)
Inventor
Bart Wattyn
Original Assignee
Strobbe Graphics Nv
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Strobbe Graphics Nv filed Critical Strobbe Graphics Nv
Priority to PCT/EP2004/005726 priority Critical patent/WO2005116721A1/fr
Publication of WO2005116721A1 publication Critical patent/WO2005116721A1/fr

Links

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
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • G02B26/10—Scanning systems
    • G02B26/12—Scanning systems using multifaceted mirrors
    • G02B26/127—Adaptive control of the scanning light beam, e.g. using the feedback from one or more detectors
    • 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
    • H04N2201/02443—Positioning method using adhesive
    • 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
    • H04N2201/04734—Detecting at frequent intervals, e.g. once per line for sub-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
    • H04N2201/04746—Detection of scanning velocity or position by detecting the scanned beam or a reference beam after modulation by a grating, mask or the like
    • 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
    • H04N2201/04798—Varying the main-scan control during the main-scan, e.g. facet tracking

Definitions

  • the invention relates to an anamorphic laser scanning device comprising a light source and means for generating a writing beam with a particular on/off frequency in function of particular data, e.g. text, photos, images.
  • the invention also relates to a method for writing data on a medium, using an anamorphic laser scanning device according the invention.
  • the anamorphic system substantially reduces the imaging system's sensitivity to cross scan errors of the scanning optic by compressing the beam in the cross scan direction onto the scanning optic.
  • the errors may be either fixed or random, such as wobble or pyramidal error. This technique is previously known in the art, as described in US patent number 3750189 (J.M. Fleischer) .
  • FIG. 1 illustrates a schematic view of a prior art laser scanning device
  • Such devices comprise a laser source (1) which produces a writing beam (2) and a polygon (5) which receives the laser beam.
  • the polygon (5) has a plurality of facets whereby only on is operative at a given time to reflect the writing beam (2) via an optical system (3; ; 5; 6; 7 ; 8 ; 9) towards an image plane (10) .
  • Each facet is operative to scan at least one line of the plane.
  • it In order for a laser scanning device to operate at high accuracy and resolution, it must accurately control the location of the writing beam (2) on the image plane (10) . Therefore it is known in current system on the market to work with two photocells (23; 24), whereby one photocell (23) detects the start of the scan and the other photocell (24) detects the end of the scan.
  • the two photocell signals are fed into an oscillator (17) whereby the oscillator (17) generates a clock signal (18) in phase of the two photocell signals.
  • the laser driver (19) switches the laser on or off in function of the clock signal (18) and the computer data (20).
  • Another known principle use the two photocells to detect the velocity of the scan line, this is used to modify a clock coming from a separate oscillator resident in the system electronics, which creates a pixel clock.
  • Fig. 2 illustrates the disadvantage of the prior art scanning devices
  • the two photocells (23; 24) measuring the total time between the start of the scan and the end of the scan (see Fig. 2b) .
  • a pixel clock is generated (see Fig. 2c) .
  • a polygon speed variation (as illustrate in Fig. 2a) occurs during the time from begin of scan and end of scan, than this polygon speed variation will only be detected by the end photocell at the end of scan.
  • the pixel clock will not been corrected during the scan and on the other hand the laser driver will send the data on the wrong time to the laser, as a result the pixels will be placed on the wrong position on the image plane (see Fig. 2d) .
  • an anamorphic laser scanning device comprising a light source and means for generating a writing beam with a particular on/off frequency, in function of particular data whereby the device comprises:
  • a reference laser source for generating a reference beam, provided to follow at least a part of the optical path of the writing beam;
  • the reference beam is folded into the optical system and travels virtually the same path as the writing beam. If any inaccuracies (speed variation, distortion, misalignments) occur during the scan, than this variation is the same for the writing beam as for the reference beam.
  • the difference between the path of the writing beam and the path of the reference beam occurs preferably after passing the final mirror.
  • said detecting means comprises a reference scale and means for generating a reference signal indicating the position and/or speed of the reference beam relative to said reference scale.
  • the detecting means comprises a number of light detectors provided along the reference scale in order to detect the position and/or speed of the reference beam relative to the reference scale.
  • the light detectors are preferable photo cells.
  • the reference scale is divided into non-transparent zones and transparent zones, and the said light detectors are provided for generating a reference signal if the reference beam travels through the transparent zone and reach said light detectors .
  • said controlling means comprises an oscillator provided for generating a clock signal based on the reference signal and a laser driver provided for controlling the on/off frequency in accordance with this clock signal.
  • the clock signal is preferable a pixel clock signal.
  • the laser driver is provided for switching the light source on or off in function of the clock signal and the data stored in a computer memory.
  • the light source is a red laser.
  • the advantage of a red laser is the fact that most media on the market is not sensitive for red laser light. As a result, any uncontrolled stray reference light will have no influence on the media. However, other laser colours can be used, if the eventually stray light is blocked from the media.
  • This patent application also relates to a method for writing data on a medium, using an anamorphic laser scanning device whereby :
  • a writing beam is generated in accordance with particular data and with a particular on/off frequency;
  • a reference beam is generated such that is follows at least a part of the optical path of the writing beam;
  • the position and/or speed of the reference beam is detected;
  • the on/off frequency of the writing beam is controlled in function of the detected position or speed of the reference beam.
  • FIG. 1 is a schematic view of a prior art laser scanning device
  • FIG. 2 illustrates the disadvantage of the prior art scanning devices
  • Fig. 2a is a graphical representation of the polygon speed
  • Fig. 2b is a graphical representation of the start and end photo cell
  • Fig. 2c is a graphical representation of the pixel clock signal
  • Fig. 2d is a graphical representation of the pixels on the image plane
  • FIG. 5 illustrates the effect of the invention on the image plan when for example a speed variation occur during the scan
  • Fig. 5a is a graphical representation of the polygon speed
  • Fig. 5b is a graphical representation of the reference signal
  • Fig. 5c is a graphical representation of the pixel clock signal
  • Fig. 5d is a graphical representation of the pixels on the image plane.
  • the device (25) according to the invention can be applied to expose one or several photosensitive plates over their entire width.
  • the laser scanning device (25) consists of a light source (1) , preferably a red laser, and means for generating a writing beam (2) with a particular on/off frequency, in function of particular data (20) .
  • the data (20) can be for example text, kanji characters, photographs or drawings and is stored in a computer memory (21) .
  • the laser emanate a writing beam (2) with a wavelength of e.g. 405, 532 nm. onto a cylindrical lens (3) after which the writing beam (2) become an anamorphic beam (2b) .
  • the writing beam (2b) After being reflected by a mirror (4), the writing beam (2b) passes via a rotating scanning optic, e.g. a polygon (5), to a lens system (6). After passing the lens system ( ⁇ ) the writing beam (2b) reflects on a first folding mirror (7) to the final folding mirror (8). After reflecting the final folding mirror (8), the writing beam (2b) proceeds via a third mirror (9) to the image plane (10) .
  • the anamorphic laser scanning device (25) further comprises a reference laser source (11), e.g. 635 nm red, for generating a reference beam (12) .
  • the reference beam (12) is folded into the optical system and travels virtually the same path as the writing beam (2b) , obtaining all the same inaccuracies that the writing beam (2b) obtains. Instead of proceeding to the image plane (10), the reference beam (12) will travel, after reflecting on the final folding mirror (8), towards detecting means (13) for detecting the position and/or speed of the reference beam (12) .
  • the detecting means (13) comprises a reference scale (14) and means (15) for generating a reference signal (16) indicating the position and/or speed of the reference beam (12) relative to said reference scale (14).
  • the detecting means (13) comprises a number of light detectors (15) , preferably photocells, provided along the reference scale (14) in order to detect the position and/or speed of the reference beam (12) relative to the reference scale (14) .
  • the reference scale (14) is divided into non-transparent zones (26) and transparent zones (27) . When the reference beam (12) passes through the reference scale (14) and is detected by the photocells (15) , the photocells (15) will generate a reference signal (16) .
  • the anamorphic laser scanning device further comprise means for controlling (17, 18, 19) said on/off frequency of the writing beam (2b) in function of the detected position and/or speed of the reference beam (12) .
  • the controlling means comprises an oscillator (17) for generating a clock signal (18), preferably a pixel clock signal, based on the reference signal (16) and a laser driver (19) provided for controlling the on/off frequency.
  • the reference signal (16) is fed into the oscillator (17), the oscillator (17) will generate the clock signal (18) and the laser driver (19) switches the laser (1) on or off in function of the clock signal (18) and the computer data (20) .
  • the advantage of the anamorphic laser scanning device according to the invention is that if any inaccuracies for example speed variation of the polygon (5) , distortion, misalignments, ... occurs during the scan, than this variation is the same for the writing beam (2b) as for the reference beam (12) .
  • reference scale (14) could easily be placed near the image plane (10) so that the reference (12) and writing beams (2b) do not have to separate before the final mirror (8) .

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Optical Scanning Systems (AREA)
  • Facsimile Scanning Arrangements (AREA)

Abstract

La présente invention se rapporte à un dispositif de balayage laser anamorphique (25), qui comprend une source lumineuse (1) et des moyens permettant de générer un faisceau d'écriture (2) présentant une fréquence marche/arrêt particulière, en fonction de données particulières (20). Le dispositif selon l'invention comprend également : une source laser de référence (11), qui génère un faisceau de référence (12) conçu pour suivre au moins une partie du trajet optique du faisceau d'écriture (2) ; des moyens (13) destinés à détecter la position et/ou la vitesse du faisceau de référence (12) ; et des moyens p (17, 18, 19) permettant de réguler ladite fréquence en fonction de la position et/ou de la vitesse détectées du faisceau de référence (12).
PCT/EP2004/005726 2004-05-25 2004-05-25 Dispositif de balayage laser anamorphique WO2005116721A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/EP2004/005726 WO2005116721A1 (fr) 2004-05-25 2004-05-25 Dispositif de balayage laser anamorphique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2004/005726 WO2005116721A1 (fr) 2004-05-25 2004-05-25 Dispositif de balayage laser anamorphique

Publications (1)

Publication Number Publication Date
WO2005116721A1 true WO2005116721A1 (fr) 2005-12-08

Family

ID=34957750

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2004/005726 WO2005116721A1 (fr) 2004-05-25 2004-05-25 Dispositif de balayage laser anamorphique

Country Status (1)

Country Link
WO (1) WO2005116721A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2168115A1 (fr) * 2007-06-27 2010-03-31 Spudnik, Inc. Commande à retroaction à base de faisceau asservi de balayage désigné dans des systèmes d'affichage à faisceau de balayage avec écrans électroluminescents
JP2015022041A (ja) * 2013-07-17 2015-02-02 国立大学法人信州大学 光ビームの走査速度の検知方法及び検知機構

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4667099A (en) * 1984-10-19 1987-05-19 Fuji Photo Film Co., Ltd. Optical linear encoder
US4853535A (en) * 1987-01-14 1989-08-01 Fuji Photo Film Co., Ltd. Light beam scanning device generating a stable synchronizing signal
US5015846A (en) * 1988-07-15 1991-05-14 Asahi Kogaku Kogyo K.K. Light beam control apparatus and linear scale device suitable for use therein
US5247373A (en) * 1989-09-14 1993-09-21 Asahi Kogaku Kogyo Kabushiki Kaisha Scanning optical system
US5852293A (en) * 1996-08-20 1998-12-22 Asahi Kogaku Kogyo Kabushiki Kaisha Raster data drawing apparatus for correcting image starting position
US6326609B1 (en) * 1998-10-12 2001-12-04 Asahi Kogaku Kogyo Kabushiki Kaisha Scanning drawing apparatus

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4667099A (en) * 1984-10-19 1987-05-19 Fuji Photo Film Co., Ltd. Optical linear encoder
US4853535A (en) * 1987-01-14 1989-08-01 Fuji Photo Film Co., Ltd. Light beam scanning device generating a stable synchronizing signal
US5015846A (en) * 1988-07-15 1991-05-14 Asahi Kogaku Kogyo K.K. Light beam control apparatus and linear scale device suitable for use therein
US5247373A (en) * 1989-09-14 1993-09-21 Asahi Kogaku Kogyo Kabushiki Kaisha Scanning optical system
US5852293A (en) * 1996-08-20 1998-12-22 Asahi Kogaku Kogyo Kabushiki Kaisha Raster data drawing apparatus for correcting image starting position
US6326609B1 (en) * 1998-10-12 2001-12-04 Asahi Kogaku Kogyo Kabushiki Kaisha Scanning drawing apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2168115A1 (fr) * 2007-06-27 2010-03-31 Spudnik, Inc. Commande à retroaction à base de faisceau asservi de balayage désigné dans des systèmes d'affichage à faisceau de balayage avec écrans électroluminescents
EP2168115A4 (fr) * 2007-06-27 2012-08-01 Prysm Inc Commande à retroaction à base de faisceau asservi de balayage désigné dans des systèmes d'affichage à faisceau de balayage avec écrans électroluminescents
JP2014112233A (ja) * 2007-06-27 2014-06-19 Prysm Inc 走査ビームシステムおよび走査ビームシステムを制御する方法
JP2015022041A (ja) * 2013-07-17 2015-02-02 国立大学法人信州大学 光ビームの走査速度の検知方法及び検知機構

Similar Documents

Publication Publication Date Title
CA1145170A (fr) Appareil et methode pour corriger les imperfections dans un polygone utilise dans le balayage par laser
JP2584111B2 (ja) 画素位置を修正する方法
US4422099A (en) Optical communication on variable power beam
JPH05278900A (ja) 媒体シート位置判定装置
US4310757A (en) Apparatus for correcting scanning speed in a polygon used for laser scanning
KR100477495B1 (ko) 광-주사 광학 시스템 및 이를 포함한 이미지-형성 장치
US4931637A (en) Scanner utilizing a particular light guide
JPH03162973A (ja) 画素位置を修正する方法
US4432598A (en) Image reading and recording apparatus and photodeflector therefor
JP3363235B2 (ja) 画像形成装置の光ビームずれ検出装置
US5889545A (en) Method and apparatus for image registration in a single pass ROS printer using a rotatable output window with no optical power
US5821971A (en) Image registration for a raster output scanner (ROS) color printer
US5412409A (en) Image registration for a raster output scanner (ROS) color printer
WO2005116721A1 (fr) Dispositif de balayage laser anamorphique
US3812371A (en) Scanning beam position indicator
KR0132366B1 (ko) 레이저 프린트 장치 및 방법
JPH07253552A (ja) 画像形成装置
KR100419219B1 (ko) 프린터 및 그의 스캐닝장치
JPH01105970A (ja) 電子写真式リーダ・プリンタ
JPH01105271A (ja) 電子写真式リーダ・プリンタ
JP3141597B2 (ja) 光学走査装置
KR101043391B1 (ko) 화상형성장치의 광주사장치
JP3532359B2 (ja) 光走査装置
US7256812B2 (en) Laser exposing apparatus
JPH0698105A (ja) 画像読み取り・記録装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BW BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NA NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GM KE LS MW MZ NA SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG

121 Ep: the epo has been informed by wipo that ep was designated in this application
NENP Non-entry into the national phase

Ref country code: DE

WWW Wipo information: withdrawn in national office

Country of ref document: DE

122 Ep: pct application non-entry in european phase