EP1738215A1 - Determining the excursion of micromirrors in a projection system - Google Patents
Determining the excursion of micromirrors in a projection systemInfo
- Publication number
- EP1738215A1 EP1738215A1 EP04804708A EP04804708A EP1738215A1 EP 1738215 A1 EP1738215 A1 EP 1738215A1 EP 04804708 A EP04804708 A EP 04804708A EP 04804708 A EP04804708 A EP 04804708A EP 1738215 A1 EP1738215 A1 EP 1738215A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- projection
- mirror
- light
- projection system
- laser
- Prior art date
- Legal status (The legal status 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 status listed.)
- Withdrawn
Links
- 238000000034 method Methods 0.000 description 10
- 230000005284 excitation Effects 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000011161 development Methods 0.000 description 4
- 230000018109 developmental process Effects 0.000 description 4
- 230000010355 oscillation Effects 0.000 description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- 238000005452 bending Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 238000005137 deposition process Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000004377 microelectronic Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 230000000930 thermomechanical effect Effects 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- 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
- G02B26/101—Scanning systems with both horizontal and vertical deflecting means, e.g. raster or XY scanners
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N5/00—Details of television systems
- H04N5/74—Projection arrangements for image reproduction, e.g. using eidophor
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3129—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen
Definitions
- the invention relates to a projection system according to the preamble of claim 1.
- Such a projection system and in particular a laser projection system is preferably used in miniaturized projection devices.
- a promising version of mini-pro ectors is the projection with the help of a laser beam deflected by a micromirror.
- the beam scans the projection area line by line, similar to the electrode beam in a cathode ray tube.
- micromirror or general microactuator The structure and operation of such a micromirror or general microactuator is briefly described below.
- microactuators which have proven themselves in the production of microelectronic components in silicon planar technology and which permit economical production. These include in particular deposition processes for layer production, photolithographic processes for structure transfer and etching processes for structuring.
- deposition processes for layer production include in particular deposition processes for layer production, photolithographic processes for structure transfer and etching processes for structuring.
- the prerequisite for the manufacture of such a microsystem is the use of actuators that can be operated with IC-compatible voltages, especially with regard to when these systems are to be used in mobile devices.
- a micromechanical scanner mirror is understood to be a micro actuator that is used for the controlled deflection of light.
- these actuators are no longer produced using conventional precision mechanical manufacturing processes, but the above-mentioned processes for microstructuring are used.
- the basic structure of such an actuator essentially consists of a reflecting mirror plate which is suspended via torsion or bending springs on a frame surrounding the mirror surface.
- the following are briefly mentioned from the multitude of control options:
- a current is impressed into a conductor loop applied to the mirror surface. If the current flow in the conductor loop changes, a twisting moment is created on the mirror plate by the external magnetic field.
- the transverse piezoelectric effect can be used to deflect a mirror plate.
- the piezoelectric layer is located between two electrodes. When electrical voltage is applied, a mechanical voltage is transmitted to the front part of the mirror plate, which causes a deflection within this area.
- electrical voltage is applied, a mechanical voltage is transmitted to the front part of the mirror plate, which causes a deflection within this area.
- the sign of the voltage U is thus a deflection upwards or downwards.
- Electrostatic excitation This control principle is sometimes the most frequently described method for using these micromechanical scanner mirrors. The process is based on the electrostatic attraction of the electrode and counterelectrode when the voltage is applied.
- the reflecting mirror plate itself is an electrode, and two counter electrodes are formed by a layer below the plate.
- the form of excitation for electrostatically deflecting the micromirrors can be roughly divided into two groups.
- the first group includes mirrors for the quasi-static deflection of light, as is often the case with lasers for material processing. Since the permanent deflection of the mirror depends on the level of the applied voltage, any low vibration frequencies can be achieved.
- the excitation of the mirror oscillation can take place in resonance, whereby, according to the mechanical quality of the system, higher deflection angles than with quasi-static excitation can be achieved.
- the vibration frequencies depend on the mechanical structure and range from a few 100Hz to a few 10kHz.
- the mirror plate itself performs the fast, resonant movement and is attached to an inner frame via two silicon torsion springs. This carries out the slow, quasi-static vibration and is in turn connected to an outer frame by two nickel torsion springs
- An image is now created by modulating the image data onto the laser beam.
- This modulated laser beam is fanned out by the scanner mirror and projected as a light beam.
- Another problem is product safety in laser projectors.
- the projection beam emerges undeflected from the projection device and can thus exceed the legal irradiation limit values. It is therefore imperative to know for sure whether the mirror is swinging. This means that the laser can be switched off when the mirror is not vibrating.
- One possible method is to measure the capacitance of the vibrating micromirror in order to obtain information about the deflection of the mirror and thus the position of the laser beam.
- this method is very complex and imprecise in terms of circuitry, since the measurement is severely disturbed by the superimposed, high excitation voltages for the mirror.
- the invention has for its object to provide a projection system with a safe and reliable position determination of the micro-oscillating mirror.
- Figure 1 the projection system according to the invention with an optical position detection
- Figure 2 a diagram for explanation.
- the position determination according to the invention takes place reliably and robustly by optical means.
- FIG. 1 shows a projection system which essentially has a laser 2 as a light source and a micro oscillating mirror 1 in a housing 4.
- the light source can also be realized by an LED or an IR LED.
- the laser 2 and the oscillation seal 1 are controlled by a control circuit 7.
- a laser beam directed onto the mirror 1 is deflected two-dimensionally by the latter and emitted as a projection light beam 6 or projection bundle through a projection opening 5 in the housing 4.
- light-sensitive components 3 are attached to the edge region of the projection light beam 6 and give corresponding feedback to the control electronics 7 if a light beam hits them. Since the geometry of the beam guidance is known, the position of the mirror 1 can be recognized on the one hand by these pulses and, on the other hand, it can be determined whether the mirror 1 is oscillating.
- 5 light-sensitive sensors 3 are attached to the edges of the projection opening 4 within the projection housing 4. These can be, for example, CCD / CMOS sensors or other photo elements. If the projection beam hits one of the sensors 3, the latter delivers a pulse which serves as a synchronization signal and thus for determining the position for controlling the micromirror 1 in the control circuit 7.
- sensors 3 are attached on both sides of the projection opening 5. Depending on the projection method, a single photo element 3 on one side can also be sufficient.
- the angle between the light beam emitted by the laser 2 and the projection light beam 6 is approximately 90 degrees.
- An arrangement is also possible in which the laser 2 is located in the vicinity of the projection opening 5.
- the angle between the light beam emitted by the laser 2 and the projection light beam 6 is approximately 30 degrees.
- the advantage of the projection system according to the invention is that the projection beam is simultaneously used for determining the position. This means that you can constantly check whether the mirror is swinging even during a projection.
- the laser must be operated with reduced power to avoid exceeding the radiation protection limit values.
- the power reduction can be brought about, for example, by pulse width modulation of the laser beam.
- the actual mirror position is measured by photoelectric elements or light-sensitive sensors 3 at the image edge and with the aid of brightness modulation of the light source.
- This modulation can be a random pattern or it can also represent a regular signal with a specific course.
- the modulation is regulated in the control circuit 7.
- the course can be determined, for example, by a counter content or line number. It is useful to use the modulation of the projection light bundle 6 in the steady state only outside the active area in the edge of the image.
- FIG. 2 shows the chronological sequence of the projection light bundle 6, for example at the projection opening 5, and a detector signal generated in the sensor 3.
- the sensor 3 changes the detector signal at a detector position as a function of the deflection of the projection beam 6.
- the oscillation amplitude of the mirror 1 can then be controlled accordingly by the controller 7, that is to say it can be enlarged or reduced, if necessary.
- the purpose of the further development is the temporal detection of the position of the light beam 6 relative to photoelectric elements which, as a rule, capture not only one image point but a range of image points in several lines with simple effort.
- the exact position of the image section relative to these calibration receivers can be determined in order to do so to synchronize the projection device and to precisely regulate the image size.
- the modulation signal can also be used to keep the energy density of the light beam low during run-up, as long as the expansion is not yet ensured by the deflection of the oscillating mirrors.
- the development of the invention results in better synchronization of the oscillating mirror 1 and thus a more precise image size regulation in deflection mirror projection systems. Furthermore, it enables a safe start-up and constant monitoring of the deflection function to prevent the energy beam from becoming too large and therefore dangerous.
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04804708A EP1738215A1 (en) | 2004-04-01 | 2004-12-07 | Determining the excursion of micromirrors in a projection system |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP04008022 | 2004-04-01 | ||
EP04804708A EP1738215A1 (en) | 2004-04-01 | 2004-12-07 | Determining the excursion of micromirrors in a projection system |
PCT/EP2004/053312 WO2005106562A1 (en) | 2004-04-01 | 2004-12-07 | Determining the excursion of micromirrors in a projection system |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1738215A1 true EP1738215A1 (en) | 2007-01-03 |
Family
ID=34924550
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP04804708A Withdrawn EP1738215A1 (en) | 2004-04-01 | 2004-12-07 | Determining the excursion of micromirrors in a projection system |
Country Status (5)
Country | Link |
---|---|
US (1) | US20070222953A1 (en) |
EP (1) | EP1738215A1 (en) |
JP (1) | JP2007531023A (en) |
CN (1) | CN101023387A (en) |
WO (1) | WO2005106562A1 (en) |
Families Citing this family (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
TWI311205B (en) * | 2006-04-28 | 2009-06-21 | Benq Corporatio | Optical system and projector utilizing the same |
JP4946964B2 (en) * | 2008-04-16 | 2012-06-06 | 船井電機株式会社 | Laser projector |
JP5428541B2 (en) * | 2009-06-03 | 2014-02-26 | リコーイメージング株式会社 | Micro mirror device |
CN101609250B (en) * | 2009-06-18 | 2011-01-05 | 北京理工大学 | Swing mirror angle scanning characteristic test device for camera |
US8636367B1 (en) * | 2010-10-15 | 2014-01-28 | Magic Lantern, Llc | System and method for controlling multiple beams illuminating projected images |
CN102540648B (en) * | 2010-12-25 | 2016-01-06 | 鸿富锦精密工业(深圳)有限公司 | Portable electron device |
TWI463241B (en) * | 2010-12-29 | 2014-12-01 | Hon Hai Prec Ind Co Ltd | Portrable electronic device |
AT514438B1 (en) | 2013-07-04 | 2015-01-15 | Zizala Lichtsysteme Gmbh | vehicle headlights |
JP6790523B2 (en) * | 2015-08-26 | 2020-11-25 | 株式会社リコー | Actuator control devices, drive systems, video equipment, image projection devices, actuator control methods, and moving objects |
DE102015222523A1 (en) * | 2015-11-16 | 2017-05-18 | Robert Bosch Gmbh | Device and method for deflecting a light beam |
DE102016200590A1 (en) * | 2016-01-19 | 2017-07-20 | Robert Bosch Gmbh | Lighting device and method for monitoring a lighting device |
CN105842971B (en) * | 2016-05-27 | 2018-05-11 | 华为技术有限公司 | A kind of projection arrangement and method |
JP7177351B2 (en) * | 2019-02-25 | 2022-11-24 | ミツミ電機株式会社 | Optical scanning device and its control method |
Family Cites Families (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CH598609A5 (en) | 1976-08-04 | 1978-05-12 | Hasler Ag | Position indicator for optical scanner or recorder |
US4686363A (en) * | 1986-01-21 | 1987-08-11 | Printware, Inc. | Self-resonant scanner biasing system |
US4934773A (en) | 1987-07-27 | 1990-06-19 | Reflection Technology, Inc. | Miniature video display system |
DE68929443T2 (en) * | 1988-09-06 | 2003-04-24 | Canon Kk | Exposure level controller |
US5032924A (en) | 1989-04-10 | 1991-07-16 | Nilford Laboratories, Inc. | System for producing an image from a sequence of pixels |
US5221933A (en) * | 1991-06-28 | 1993-06-22 | Eastman Kodak Company | Beam scanning galvanometer with low inertia mirror and magnet |
US5519518A (en) * | 1993-12-27 | 1996-05-21 | Kabushiki Kaisha Toshiba | Display apparatus with a variable aperture stop means on each side of the modulator |
US5930019A (en) * | 1996-12-16 | 1999-07-27 | Fuji Xerox Co., Ltd. | Light scanning device, optical device, and scanning method of optical device |
US20010007483A1 (en) * | 1997-01-24 | 2001-07-12 | Jacques Chauvin | Circuit for convergence setting in a projection television display |
US6636274B1 (en) * | 1999-08-10 | 2003-10-21 | Kabushiki Kaisha Toshiba | Image display device |
JP4199893B2 (en) | 1999-12-28 | 2008-12-24 | 株式会社リコー | Image forming apparatus |
DE10024079A1 (en) * | 2000-05-17 | 2001-11-22 | Asclepion Meditec Ag | Determining energy and position of pulsed laser beam of ophthalmologic excimer laser for cornea surgery, deflects beam periodically onto measurement sensor |
US7423787B2 (en) * | 2001-03-01 | 2008-09-09 | Ricoh Company, Ltd. | Optical scanning module, device, and method, and imaging apparatus |
US6937372B2 (en) * | 2001-07-11 | 2005-08-30 | Canon Kabushiki Kaisha | Light beam deflecting apparatus, image forming apparatus utilizing the same and drive method therefor |
US6844951B2 (en) * | 2002-12-23 | 2005-01-18 | Lexmark International, Inc. | Stationary coil oscillator scanning system |
JP4088188B2 (en) * | 2003-04-07 | 2008-05-21 | セイコーエプソン株式会社 | projector |
US7133061B2 (en) * | 2004-06-14 | 2006-11-07 | Texas Instruments Incorporated | Multilaser bi-directional printer with an oscillating scanning mirror |
JPWO2006115210A1 (en) * | 2005-04-22 | 2008-12-18 | 松下電器産業株式会社 | Projection display device |
US7436564B2 (en) * | 2005-08-03 | 2008-10-14 | Seiko Epson Corporation | Light scanning apparatus and method to prevent damage to an oscillation mirror in an abnormal control condition via a detection signal outputted to a controller even though the source still emits light |
-
2004
- 2004-12-07 WO PCT/EP2004/053312 patent/WO2005106562A1/en not_active Application Discontinuation
- 2004-12-07 JP JP2007505393A patent/JP2007531023A/en active Pending
- 2004-12-07 EP EP04804708A patent/EP1738215A1/en not_active Withdrawn
- 2004-12-07 US US10/599,515 patent/US20070222953A1/en not_active Abandoned
- 2004-12-07 CN CNA2004800426757A patent/CN101023387A/en active Pending
Non-Patent Citations (1)
Title |
---|
See references of WO2005106562A1 * |
Also Published As
Publication number | Publication date |
---|---|
CN101023387A (en) | 2007-08-22 |
US20070222953A1 (en) | 2007-09-27 |
JP2007531023A (en) | 2007-11-01 |
WO2005106562A1 (en) | 2005-11-10 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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17P | Request for examination filed |
Effective date: 20060810 |
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AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): DE FR GB IT |
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17Q | First examination report despatched |
Effective date: 20070124 |
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19U | Interruption of proceedings before grant |
Effective date: 20070101 |
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19W | Proceedings resumed before grant after interruption of proceedings |
Effective date: 20090602 |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: PALM, INC. Owner name: SIEMENS AKTIENGESELLSCHAFT |
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RAP1 | Party data changed (applicant data changed or rights of an application transferred) |
Owner name: PALM, INC. |
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R17C | First examination report despatched (corrected) |
Effective date: 20091005 |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20100701 |