WO2020202011A1 - Procédé et appareil de projection d'image laser à granularité réduite - Google Patents

Procédé et appareil de projection d'image laser à granularité réduite Download PDF

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Publication number
WO2020202011A1
WO2020202011A1 PCT/IB2020/053065 IB2020053065W WO2020202011A1 WO 2020202011 A1 WO2020202011 A1 WO 2020202011A1 IB 2020053065 W IB2020053065 W IB 2020053065W WO 2020202011 A1 WO2020202011 A1 WO 2020202011A1
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WO
WIPO (PCT)
Prior art keywords
objective lens
optical pickup
pickup actuator
axis
coil
Prior art date
Application number
PCT/IB2020/053065
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English (en)
Inventor
Chang-Qing Xu
Mahmoud Mohamed Talaat Mohamed Ibrahim Eldesouky Khalil MOHAMED
Liam FLANNIGAN
Qianli Ma
Original Assignee
Mcmaster University
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 Mcmaster University filed Critical Mcmaster University
Publication of WO2020202011A1 publication Critical patent/WO2020202011A1/fr

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    • 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]
    • H04N9/3141—Constructional details thereof
    • H04N9/315—Modulator illumination systems
    • H04N9/3161—Modulator illumination systems using laser light sources
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/48—Laser speckle optics

Definitions

  • the specification relates generally to apparatus and methods associated with laser projection, and more specifically to speckle reduced laser image projection.
  • U.S. Pat. No. 7,271 ,962 purports to disclose a two-dimensional image formation apparatus provided with laser sources, diffusers for diffusing light, illumination optical systems for irradiating the diffusers with lights emitted from the laser sources, diffuser vibration units for vibrating the diffusers, and spatial light modulators disposed near the diffusers, for modulating the lights emitted from the laser sources and diffused by the diffusers, wherein the diffusers are vibrated by the diffuser vibration units at a velocity that satisfies a relationship, V>dx30 (millimeters/sec), which is established between the grain size d of the diffusers and the vibration speed V of the diffusers, whereby speckle noise existing in an image projected on a screen can be effectively reduced.
  • V>dx30 millimeters/sec
  • U.S. Pat. No. 6,895,149 purports to disclose an invention which greatly improves the quality of images obtained using optical systems illuminated by coherent light. It does so by removing the undesirable pseudo-random variations in the final image due to interference speckle and inhomogeneities in the spatial intensity distribution of the light source.
  • a bundle of light-guiding fibers is interposed between the illumination source and the imaging system. Non-uniform propagation within the fiber bundle creates a pseudo-random phase variation across the illumination beam, which gives rise to a dynamic interference speckle pattern superimposed upon the desired image acquired by the optical system.
  • Rotating the fiber bundle around the axis of propagation whilst simultaneously integrating the output of the photosensitive detector over a period of time, substantially removes variations due to source inhomogeneities and coherent interference.
  • U.S. Pat. App. No. 2014/0071406 purports to disclose an apparatus comprising a laser and/or LED light source(s), multimode optical fiber(s), light coupler(s), an optional spatial light modulator(s), and an optional projection lens(es).
  • the light source has a 1/e half-width emission bandwidth.
  • the light coupler couples the light source to the multimode optical fiber(s) such that objective speckle contrast is reduced.
  • the multimode optical fiber(s) may pass light from the coupler to an optional spatial light modulator.
  • the spatial light modulator may modulate the light to form an image.
  • the projection lens may transfer light onto an image plane or to illuminate objects.
  • the objective speckle contrast at the end of the multimode fiber in combination with the projection lens diameter (if employed) and wavelength diversity may result in viewed images at the viewer's eye, or other detector, exhibiting speckle contrast that may be 1 % or less.
  • a speckle reducing system may comprise at least one actuating element located proximate to, but not in physical contact with, a display screen.
  • the at least one actuating element may be configured to generate waves directed towards the display screen. When the waves impact the display screen, the waves impart vibration to the display screen.
  • U.S. Pat. No. 9,778,478 purports to disclose a projector with image plane modal vibration for speckle reduction.
  • the projector includes: a laser light source; a light modulator; and optics that convey light from the laser to the modulator and project modulated light from the modulator, the optics comprising an image plane.
  • the projector further includes: a surface comprising at least a first region located at the image plane, the first region being at least as large as an image formed at the image plane, the first region configured to one or more of transmit and reflect the image; and at least three actuators, positions of interaction of the actuators with the surface are asymmetric relative to the surface, the actuators configured to generate respective moving surface waves in the first region at respective frequencies, the respective frequencies comprising non-integer multiples of each other.
  • U.S. Pat. App. No. 2008/0192327 purports to disclose a system and method for reducing speckle of a laser beam.
  • the system includes at least an active device capable of temporally and/or spatially averaging the speckle pattern of a laser.
  • the device can be used with an external diffuser or have an integrated diffusive layer within its structure to enhance the speckle reduction.
  • the speckle reduction system alters the phase and/or path of light rays within an input laser beam as they pass through a transmissive device or reflect off of the surface of a reflective device.
  • a laser image projector comprising a laser source to project a laser beam along a projection path; an optical pickup actuator fixed adjacent the laser source, the optical pickup actuator including an objective lens held in the projection path, the objective lens having an optical axis parallel to a first portion of the projection path extending through the objective lens, the objective lens having a focusing axis parallel to the optical axis and a tracking axis perpendicular to the focusing axis, a focusing coil coupled to the objective lens to move the objective lens along the focusing axis, a tracking coil coupled to the objective lens to move the objective lens along the tracking axis, and a control unit coupled to at least one of the focusing coil and the tracking coil and operable to supply a time varying current to the at least one of the focusing coil and the tracking coil to generate an electromagnetic force to induce a vibrating movement in the objective lens during a projection of the laser beam; and a set of projection optics received in the projection path, and wherein the
  • the projection optics includes a diffuser and a projection lens each received in the projection path, and the diffuser received in the projection path between the optical pickup actuator and the projection lens.
  • the projection optics includes a condensing lens and at least one homogenization component each received in the projection path after the optical pickup actuator.
  • the time varying current is an alternating current.
  • the time varying current has a frequency of between 30 Hz and 120 Hz.
  • the time varying current has a voltage of between 1 volt and 4 volts.
  • increasing a voltage amplitude of the time varying current increases a vibration amplitude of the vibrating movement
  • decreasing the voltage amplitude of the time varying current decreases the vibration amplitude of the vibrating movement
  • an optical pickup actuator for a laser image projector comprising an objective lens having an optical axis, the objective lens having a focusing axis parallel to the optical axis and a tracking axis perpendicular to the focusing axis; a focusing coil coupled to the objective lens to move the objective lens along the focusing axis; a tracking coil coupled to the objective lens to move the objective lens along the tracking axis; and a control unit coupled to at least one of the focusing coil and the tracking coil, and operable to supply a time varying current to the at least one of the focusing coil and the tracking coil to generate an electromagnetic force to induce a vibrating movement in the objective lens during a projection of a laser beam through the objective lens.
  • the time varying current is an alternating current.
  • the time varying current is a square wave current.
  • the time varying current has a frequency of between 30 Hz and 120 Hz.
  • the time varying current has a frequency of between 60 Hz and 80 Hz.
  • the time varying current has a voltage of between 1 volt and 4 volts.
  • the varying current has a voltage of between 1 volt and 2 volts.
  • each of the focusing coil and the tracking coil includes a copper wire wrapped around a magnetic core.
  • the objective lens is secured in a lens casing, and wherein an extent of the vibrating movement is limited to a dimension of the lens casing.
  • the at least one of the focusing coil and the tracking coil is the tracking coil.
  • an optical pickup actuator for a laser image projector comprising an objective lens having an optical axis; a movement coil coupled to the objective lens to move the objective lens along a movement axis, the movement axis perpendicular or parallel to the optical axis; and a control unit coupled to the movement coil and operable to supply a time varying current to the movement coil to generate an electromagnetic force to induce in the objective lens a vibrating movement along the movement axis during a projection of a laser beam through the objective lens.
  • Figure 1 is a schematic diagram of a laser image projector
  • Figure 2 is a schematic diagram of a first optical pickup actuator
  • Figure 3 is a schematic diagram of a vibrating second optical pickup actuator
  • Figure 4 is a graph of a vibration amplitude as a function of a driving frequency for a four peak voltages
  • Figure 5 are graphs of speckle contrast ratio as a function of vibration frequency and peak voltage for two example laser sources
  • Figure 6 are pictures of projected speckle images
  • Figure 7 is a schematic diagram of vibrating third and fourth optical pickup actuators
  • Figure 8 is a schematic diagram of a second laser image projector
  • Figure 9 is a schematic diagram of a third laser image projector.
  • an example of an optical pickup actuator 106 is depicted.
  • the optical pickup actuator 106 is a speckle-reducing member.
  • the optical pickup actuator 106 is a speckle-reducing member for use in a laser image projector.
  • the optical pickup actuator 106 includes an objective lens operable to be vibrated during a projection of a laser beam through the objective lens. In some examples, vibrating an objective lens perpendicular and/or parallel to the propagation direction of a laser beam passing through the objective lens reduces the time-coherence of the laser light and results in improved image quality.
  • laser speckle is the set of random interference patterns generated by the coherent light source impinging on a rough surface. These interference patterns cause the intensity of the light to vary randomly, resulting in a grainy image of reduced quality.
  • laser speckle can take the form of image noise.
  • the speckle is described using the Speckle Contrast Ratio (SCR).
  • SCR Speckle Contrast Ratio
  • a SCR greater than 5% results in a degraded image.
  • a SCR greater than 5% is noticeable to the human eye.
  • a laser image projector includes one or more speck-reducing member.
  • laser speckle can take the form of image noise that can distract the viewer.
  • laser speckle can affect laser scanning applications, where a laser is used to detect a line or spot.
  • laser speckle can introduce errors to a scan.
  • errors introduced to a scan due to laser speckle prevent a laser scanning apparatus from locating a center point.
  • laser speckle causes issues in LIDAR systems, resulting in erroneous distance measurements that decrease measurement reliability.
  • the optical pickup actuator 106 is part of a laser image projector 100.
  • the laser image projector includes a laser source 102 to project a laser beam along a projection path 103, the optical pickup actuator 106 fixed adjacent the laser source in the projection path 103, and a set of projection optics 1 10 received in the projection path 103 following the optical pickup actuator 106.
  • the laser source 102, the optical pickup actuator 106, and the set of projection optics 1 10 are contained in a housing 1 1 1 .
  • the housing 1 1 1 is a portable housing.
  • the housing 1 1 1 is a mountable housing to be mounted to a wall or ceiling or rested on a desk or table.
  • the set of projection optics 1 10 includes a projection lens through which the projection path 103 passes out of the housing 1 1 1 .
  • the optical pickup actuator 106 includes an objective lens.
  • the objective lens is a laser coupling lens received in the projection path 103 between the laser source 102 and the set of projection optics 1 10.
  • FIG. 2 illustrated is an example of an optical pickup actuator 206.
  • the illustrated example optical pickup actuator 206 is similar in many respects to the optical pickup actuator 106, and like features are indicated with like reference numbers incremented by 100.
  • the optical pickup actuator 206 includes an objective lens 214 to be held in a projection path of a laser source.
  • the objective lens 214 includes an optical axis 215.
  • the illustrated example objective lens 214 also includes a focusing axis 216 parallel to the optical axis 215 and at least one tracking axis 217 perpendicular to the focusing axis 216.
  • the objective lens 214 includes at least one movement axis along which the objective lens 214 can be linearly moved and at least one movement coil coupled to the objective lens 214 to move the objective lens 214 along the movement axis.
  • the movement axis is perpendicular or parallel to the optical axis.
  • the at least one movement axis includes at least one of the tracking axis 217 and the focusing axis 216.
  • the movement coil includes at least one of a focusing coil 218 coupled to the objective lens 214 to move the objective lens 214 along the focusing axis 216 and a tracking coil 222 coupled to the objective lens 214 to move the objective lens 214 along the tracking axis 217.
  • an optical pickup actuator 206 includes only a single tracking coil 222 and a single focusing coil 218.
  • an optical pickup actuator 206 including only a single tracking coil 222 and a single focusing coil 218 is a simpler optical pickup actuator and/or more economical optical pickup actuator.
  • the movement coil is only one of a single focusing coil 218 or a single tracking coil 222. In some examples, the movement coil is the tracking coil 222. In some examples, the movement coil as the tracking coil 222 produces more effective vibrational movement than the movement coil as the focusing coil 218.
  • the movement coil includes a copper wire wrapped around a magnetic core.
  • each of the focusing coil 218 and the tracking coil 222 includes a copper wire wrapped around a magnetic core.
  • one or both of the focusing coil 218 and the tracking coil 222 is actuated by passing a current through the copper wire to generate electromagnetic force.
  • the focusing coil 218 is operable to move the objective lens 214 parallel to the light propagation direction, which serves to help focus a laser beam onto a target.
  • the tracking coil 222 is operable to move the objective lens 214 perpendicular to the light propagation direction. In some examples, having both the focusing coil 218 and the tracking coil 222 allows 2-dimensional objective lens motion of the objective lens 214.
  • the optical pickup actuator 206 includes a control unit 226 coupled to the at least one movement coil to supply a time varying current to the at least one movement coil.
  • supplying the time varying current to the at least one movement coil generates an electromagnetic force and induces a vibrating movement in the objective lens 214.
  • the control unit 226 is coupled to the at least one movement coil to supply a time varying current to the at least one movement coil and is operable to supply a time varying current to the at least one movement coil to generate an electromagnetic force to induce a vibrating movement in the objective lens 214 during a projection of a laser beam through the objective lens 214.
  • the time varying current changes the laser direction rapidly. In some examples, the time varying current changes the laser direction rapidly to generate homogenized light fields with reduced SPR. In some examples, an objective lens vibrates at a small amplitude with high frequency. In some examples, an objective lens vibrates to introduce speckle reduction without reducing image quality. In some examples, an objective lens vibrates at a small amplitude with high frequency to introduce speckle reduction without reducing image quality.
  • multiple independent speckle patterns are generated.
  • multiple independent speckle patterns reduce overall speckle over the integration time of a detector.
  • a detector is a human eye.
  • vibration frequency and vibration amplitude determine effectiveness in reducing laser speckle.
  • one or more speckle reduction components require space for the speckle reduction component itself, as well as one or more motors and/or coil required to move, rotate, or vibrate the speckle reduction component.
  • speckle reduction components increase one or more of system size, system weight, and system power consumption of a laser projection system.
  • a vibrating optical pickup actuator is a speckle reduction component with comparatively small size and/or power consumption.
  • vibrating an objective lens by passing current through one or more coils attached to the objective lens and/or an objective lens holder or housing results in a low power consumption and/or small device size speckle reduction component.
  • control unit 226 is coupled to at least one of the focusing coil 218 and the tracking coil 222.
  • the illustrated control unit 226 is operable to supply a time varying current to the at least one of the focusing coil 218 and the tracking coil 222 to generate an electromagnetic force to induce a vibrating movement in the objective lens 214 during a projection of a laser beam through the objective lens 214.
  • optical pickup actuator 206 includes or is coupled to a power source from which the control unit 226 is operable to supply a time varying current.
  • the power source is external to the optical pickup actuator 206 and/or a laser image projector that includes the optical pickup actuator.
  • the power source is a dedicated power source for supplying power to vibrate the optical lens.
  • the power source is a common power source used for other power requirements of the optical pickup actuator 206 and/or a laser image projector that includes the optical pickup actuator.
  • the power sources includes at least one of a battery and a wall outlet of a power grid.
  • the time varying current supplied by the control unit 226 is a variable current. In some examples, the time varying current supplied by the control unit 226 is a periodic or pulsating current. In some examples, the time varying current supplied by the control unit 226 is an alternating current. In some examples, the time varying current supplied by the control unit 226 is a square wave current. In some examples, a regular pulsating current results in a more predictable vibration movement of the objective lens 214 than a variable current.
  • the time varying current has a voltage of between 1 volt and 4 volts. In some examples, the varying current has a voltage of between 1 volt and 2 volts. In some examples, increasing a voltage amplitude of the time varying current increases a vibration amplitude of the vibrating movement. In some examples, decreasing the voltage amplitude of the time varying current decreases the vibration amplitude of the vibrating movement. In some examples, the time varying current has a frequency of between 30 Hz and 120 Hz. In some examples, the time varying current has a frequency of between 60 Hz and 80 Hz.
  • the objective lens 214 is secured in a lens casing 230.
  • the vibrating movement of the objective lens 214 is limited to a dimension of the lens casing 230.
  • the lens casing 230 may include a lens holder, and the vibrational movement of the objective lens 214 may be constrained by a dimension of the lens holder.
  • FIG. 3 illustrated is an example of an optical pickup actuator 306 being vibrated.
  • the illustrated example optical pickup actuator 306 is similar in many respects to the optical pickup actuator 106, and like features are indicated with like reference numbers incremented by 200.
  • the illustrated optical pickup actuator 306 is being vibrated in a movement direction 334.
  • the movement direction 334 is along the tracking axis 317 and perpendicular to the focusing axis 316.
  • the control unit is supplying a time varying current to the tracking coil coupled to the objective lens to move the objective lens along the tracking axis 317.
  • a laser scan line 338 is shown schematically on screen 342.
  • the laser scan line 338 is produced by the direction of vibration.
  • FIG. 4 illustrated are experimental results for an example laser image projection system.
  • an optical pickup actuator 306 was used.
  • the tracking coil 322 was driven with alternating current with a square wave from a multifunction generator at four separate peak voltages; 1 V peak voltage, 1 .5 V peak voltage, 2 V peak voltage, and 4 V peak voltage.
  • Two green laser sources where used in separate tests.
  • the two green laser sources were a frequency doubled diode pumped solid state (DPSS) green laser emitting at 532 nm and a semiconductor green laser diode (Diode) emitting at 515 nm and having an attached Peltier element to stabilize the operating temperature.
  • DPSS frequency doubled diode pumped solid state
  • Diode semiconductor green laser diode
  • the example experimental setup included a laser placed at a built-in focal length of the optical pickup actuator 306 and then coupled into the optical pickup actuator 306.
  • the optical pickup actuator 306 output was launched into a 50x microscopic lens (acting as a projecting lens) before reaching a white paper projector“screen”.
  • a charged-coupled device (CCD) camera was placed behind the laser projection screen to capture the shape of the imaged amplitude.
  • Different driving signals were used for the lens vibrating module to test the effect of vibration frequency and amplitude on SCR reduction.
  • the output of the optical pickup actuator 306 was passed into a diffuser.
  • the diversity annihilated the temporal and spatial coherence of the laser beam, creating multiple speckle patterns that were averaged over the integration time of the detector.
  • FIG. 4 Illustrated in Figure 4 is a graph 437 of a vibration amplitude as a function of a driving frequency for the example tracking coil 322.
  • Graphed in the graph 437 are four peak voltages; 1 V peak voltage 439, 1 .5 V peak voltage 440, 2 V peak voltage 441 , and 4 V peak voltage 443.
  • the tracking coil 322 was driven with a square wave, and the different lines represent different peak voltages.
  • the line is a result of the vibration of the objective lens, which produces a bright laser line as opposed to the typical Gaussian beam dot that is observable when the optical pickup actuator 306 is turned off.
  • the vibration amplitude hit a maximum in the 60- 80 Hz range.
  • higher peak voltages increased vibration amplitude.
  • the time varying current supplied was an alternating current from a multifunction generator applied on the tracking coil 322.
  • the graph 545 is of a frequency doubled diode pumped solid state (DPSS) green laser emitting at 532 nm. Graphed in the graph 545 are four peak voltages; 1 V peak voltage 548, 1 .5 V peak voltage 549, 2 V peak voltage 551 , and 4 V peak voltage 552.
  • DPSS frequency doubled diode pumped solid state
  • the graph 547 is of a semiconductor green laser diode (Diode) emitting at 515 nm, which had an attached Peltier element to stabilize the operating temperature.
  • Graphed in the graph 547 are four peak voltages; 1 V peak voltage 553, 1 .5 V peak voltage 554, 2 V peak voltage 555, and 4 V peak voltage 556.
  • example graphs 545, 547 the reduction in SCR was maximized around the 70 Hz peak, which aligns with the maximum amplitude of vibration before saturating in Figure 4.
  • the example graphs 545, 547 also illustrate that the SCR will, in some examples, return to previous values quickly once the optimal driving frequency is surpassed. In some examples, care must be taken to select the correct driving frequency and/or amplitude to maximize speckle reduction.
  • the illustrated examples are the speckle contrast ratio and speckle image for both the DPSS and Diode in multiple situations.
  • Shown in Figures 6C and 6D are the SCR and speckle image for the DPSS without the diffuser when the optical pickup actuator 306 is off and when the optical pickup actuator 306 is on, respectively.
  • Shown in Figures 6E and 6F are the SCR and speckle image for the Diode without the diffuser when the optical pickup actuator 306 is off and when the optical pickup actuator 306 is on, respectively.
  • Shown in Figures 6G and 6H are the SCR and speckle images for the DPSS with the diffuser when the optical pickup actuator 306 is off and when the optical pickup actuator 306 is on, respectively.
  • Shown in Figures 6I and 6J are the SCR and speckle images for the Diode with the diffuser when the optical pickup actuator 306 is off and when the optical pickup actuator 306 is on, respectively.
  • the efficiency of the optical pickup actuator 306 without the diffuser from the original SCR shows a reduction of 31 .75% for the DPSS and 32.22% for the Diode.
  • the total efficiency comparing the original speckle values to the final speckle values with the optical pickup actuator 306 and the diffuser are 66.35% for the DPSS and 76.19% for the Diode.
  • a laser image projector includes more than one optical pickup actuator, each having a single movement coil operable to induce in an objective lens a vibrating movement.
  • a laser image projector includes two optical pickup actuators, each having a single movement coil operable to induce in an objective lens a vibrating movement, and each optical pickup actuator operable to move an objective lens perpendicular to a propagation direction of a laser beam therethrough and perpendicular to one another.
  • optical pickup actuators 406 and 506 each being vibrated.
  • the illustrated example optical pickup actuators 406 and 506 are similar in many respects to the optical pickup actuator 106, and like features are indicated with like reference numbers incremented by 300 and 400, respectively.
  • the optical pickup actuators 406 and 506 are each vibrating in a direction perpendicular to both the propagation direction of the laser beam and the vibration direction of the other optical pickup actuator 406, 506, producing a 2D scan line 646 as a combination of the two directions of vibration.
  • the optical pickup actuator 406 is being vibrated in a movement direction 435.
  • the movement direction 435 is along a tracking axis 458 perpendicular to the focusing axis 416.
  • the control unit is supplying a time varying current to the tracking coil coupled to the objective lens to move the objective lens along the tracking axis 458.
  • the optical pickup actuator 506 is being vibrated in a movement direction 534.
  • the movement direction 534 is along a tracking axis 517 perpendicular to the focusing axis 516 and the tracking axis 458.
  • the control unit is supplying a time varying current to the tracking coil coupled to the objective lens to move the objective lens along the tracking axis 517.
  • FIG. 8 illustrated is an example of a laser image projector 700.
  • the illustrated example laser image projector 700 is similar in many respects to the laser image projector 100, and like features are indicated with like reference numbers incremented by 600.
  • a laser source 702 is coupled into one or two optical pickup actuators 706 to project a laser beam along a projection path 703.
  • the one or two optical pickup actuators 706 are fixed adjacent the laser source 702 in the projection path 703, and are between the laser source 702 and a set of projection optics 710.
  • an objective lens of the one or two optical pickup actuators 706 has an optical axis parallel to a first portion 705 of the projection path 703 extending through the objective lens.
  • a third optical pickup actuator is added.
  • a third optical pickup actuator is added to a position close to the projection lens 766 and in the projection path to further improve speckle reduction.
  • a set of projection optics 710 includes only a projection lens 766.
  • the projection optics 710 includes, received in the projection path 703 ahead of the projection lens 766, one or more of a diffuser 754, a condensing lens 750, a homogenization component 758, and intermediate optics 762.
  • the homogenization component 758 is a homogenizing light pipe, as illustrated in Figure 8.
  • the projecting lens 766 directs the projection path 703 to a screen 770.
  • the de-speckle effects of the one or two optical pickup actuators 706 can be enhanced by employing a condensing lens, since the condensing lens can facilitate directing the light waves towards the homogenization component of the system.
  • the intermediate optical elements 762 are used for collecting the refined adjusted light from the homogenization component 758.
  • FIG. 9 illustrated is an example of a laser image projector 800.
  • the illustrated example laser image projector 800 is similar in many respects to the laser image projector 100, and like features are indicated with like reference numbers incremented by 700.
  • a laser source 802 is coupled into one or two optical pickup actuators 806 to project a laser beam along a projection path 803.
  • the one or two optical pickup actuators 806 are fixed adjacent the laser source 802 in the projection path 803, and are between the laser source 802 and a set of projection optics 810.
  • a set of projection optics 810 includes only a projection lens 866.
  • the projection optics 810 includes, received in the projection path 803, one or more of a diffuser 854, a condensing lens 850, a homogenization component 858, and intermediate optics 862.
  • the homogenization component 858 is a homogenizing lens array, as illustrated in Figure 9.
  • the projecting lens 866 directs the projection path 803 to a screen 870.
  • a third optical pickup actuator is added.
  • a third optical pickup actuator is added to a position close to the projection lens 866 and in the projection path to further improve speckle reduction.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • General Physics & Mathematics (AREA)
  • Projection Apparatus (AREA)

Abstract

Actionneur de capture optique pour un projecteur d'image laser comprenant une lentille d'objectif ayant un axe optique ; une bobine de mouvement couplée à la lentille d'objectif pour déplacer la lentille d'objectif le long d'un axe de mouvement, l'axe de mouvement étant perpendiculaire ou parallèle à l'axe optique ; et une unité de commande couplée à la bobine de mouvement et actionnable pour fournir un courant variant dans le temps à la bobine de mouvement pour générer une force électromagnétique pour induire dans la lentille d'objectif un mouvement vibratoire le long de l'axe de mouvement pendant une projection d'un faisceau laser à travers la lentille d'objectif.
PCT/IB2020/053065 2019-04-01 2020-03-31 Procédé et appareil de projection d'image laser à granularité réduite WO2020202011A1 (fr)

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US62/827,451 2019-04-01

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003021806A (ja) * 2001-07-09 2003-01-24 Matsushita Electric Ind Co Ltd 背面投射型ディスプレイ
US20110235003A1 (en) * 2007-08-09 2011-09-29 Konica Minolta Opto, Inc. Laser projector and image projection method
US20130113788A1 (en) * 2011-11-08 2013-05-09 Reald Inc. Imaging path speckle mitigation

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003021806A (ja) * 2001-07-09 2003-01-24 Matsushita Electric Ind Co Ltd 背面投射型ディスプレイ
US20110235003A1 (en) * 2007-08-09 2011-09-29 Konica Minolta Opto, Inc. Laser projector and image projection method
US20130113788A1 (en) * 2011-11-08 2013-05-09 Reald Inc. Imaging path speckle mitigation

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