WO1998024240A1 - Systeme d'affichage a balayage par faisceaux laser multiples - Google Patents

Systeme d'affichage a balayage par faisceaux laser multiples Download PDF

Info

Publication number
WO1998024240A1
WO1998024240A1 PCT/US1997/021545 US9721545W WO9824240A1 WO 1998024240 A1 WO1998024240 A1 WO 1998024240A1 US 9721545 W US9721545 W US 9721545W WO 9824240 A1 WO9824240 A1 WO 9824240A1
Authority
WO
WIPO (PCT)
Prior art keywords
beamlets
laser
scanning
laser light
line
Prior art date
Application number
PCT/US1997/021545
Other languages
English (en)
Other versions
WO1998024240B1 (fr
Inventor
David E. Hargis
Charles G. Fink
Robert A. Bergstedt
Graham W. Flint
Original Assignee
Laser Power Corporation
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 Laser Power Corporation filed Critical Laser Power Corporation
Priority to AU74128/98A priority Critical patent/AU7412898A/en
Publication of WO1998024240A1 publication Critical patent/WO1998024240A1/fr
Publication of WO1998024240B1 publication Critical patent/WO1998024240B1/fr

Links

Classifications

    • 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
    • H04N9/3132—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] scanning a light beam on the display screen using one-dimensional electronic spatial light modulators

Definitions

  • This invention relates to projection and display systems. Additionally, it relates to projection display systems utilizing laser light.
  • Direct-emission projectors emit their own light.
  • the most common direct-emission device is the CRT projector, used in home TV projectors and in high power versions for large screen industrial use.
  • Direct-emission projectors are inherently simpler than light-modulation projectors.
  • the direct emission projector consists only of a controllable light source and optics.
  • the evolution of the CRT projector illustrates how, owing to its inherent simplicity, a direct-emission display mechanism can be readily produced and later scaled-up to higher brightness and resolution levels.
  • CRT Projectors To better understand the nature of limitations associated with previous technology, it becomes instructive to review briefly the operating characteristics of four principal contenders in the video projection arena. In order of review, these contenders are as follows: CRT projectors, light valve projectors, passive-matrix panels and active-matrix panels. CRT Projectors
  • Projection CRTs are similar to conventional monochrome CRTs, except that they are operated at much higher beam currents. Color systems are built using three independent CRT systems, each with its own lens. The user must make periodic convergence adjustments to bring the three beams into color registration. Attempts to produce single-lens projectors, where the three color tubes are internally converged at the factory, have not been widely accepted.
  • Light valve projectors have been developed to overcome some of the deficiencies of the CRT projectors.
  • An advantage of light valve systems is that the light source and modulating element are decoupled.
  • Light valve projectors based on the electron beam oil film light valve were developed over 25 years ago. In such systems, an oil film is used as the image source. Intensity of the projected light is controlled by the amplitude of the deformation of the oil film. However, they are very complex, bulky, expensive, and are difficult to set up and maintain.
  • the LCD light valve An alternative to the oil film approach is provided by the LCD light valve.
  • the LCD matrix is not used as a simple shutter that reduces the input light, but as a stimulus responsive to the input signal is used to activate the LCD material, which then is coupled to a separate output light source.
  • Extremely high resolutions (5000 x 7000) have been achieved via the LCD approach.
  • the writing rate is very slow at this resolution, requiring 3.5 minutes to update a display using two 40 milliwatt lasers. Ultra high resolution is thus offset by very slow writing speed and very high cost.
  • a simpler method for using an LCD panel as a light modulator is that of interposing the
  • Such panels can be activated by either of two approaches, either passive-matrix and active-matrix.
  • passive and active drive technologies the LCD cells are arranged in a matrix of rows and columns, and are driven by row and column driver circuits.
  • the LCD cell alone exists at each intersection.
  • a time-multiplexing scheme is used to energize each of the LCD cells in the matrix.
  • the slow response time of passive-matrix panels makes them unsuitable for displaying quickly changing information such as television signals.
  • crosstalk between LCD cells is a significant disadvantage.
  • An active-matrix panel contains a switching device such as a thin film transistor (TFT), and a storage element (capacitor), in addition to the LCD cell at every LCD site.
  • TFT thin film transistor
  • Capacitor storage element
  • Each switch/capacitor acts as a "sample-hold" (S/H) circuit for the briefly appearing pulses from the multiplexed drive system.
  • S/H sample-hold
  • Each LCD cell, driven by its own S H circuit, is thus decoupled from the other LCD cells, minimizing crosstalk.
  • active-matrix LCD cells can be "sample-hold"
  • the invention comprises a scanning display system which uses a plurality of laser sources to produce images.
  • the laser sources may be diode pumped microlaser, diode laser arrays or other suitable sources of laser light.
  • One embodiment of the invention is a high resolution image project system, comprising: a laser source for each of the three primary colors of the image projection system; a beam shaping apparatus to form multiple beamlets from the laser light from the laser sources; a modulating system for modulating the beamlets; an apparatus for two dimensional scanning of the outputs of each said combined laser beam output; and an optical means for forming the scanned beams into a projection beam.
  • Figure 1 is a conceptual schematic diagram of a display system.
  • Figure 2 is a schematic diagram of functional elements of a display system.
  • Figure 3 is a plan view of a dichroic prism assembly.
  • Figure 4 is a perspective view of a scanning polygon.
  • Figure 5 is a perspective view of a 120-element per centimeter individually addressable microlaser array including a heat sink and a thermoelectric cooler (TEC).
  • TEC thermoelectric cooler
  • Figure 6 is a plan view of a microlaser array projection system.
  • Figure 7 is a perspective view of the system of Figure 6.
  • Figure 8 is a conceptual representation of a speckle eliminator.
  • Figure 9 illustrates a diode laser-pumped microlaser.
  • Figure 10 is a conceptual diagram of a 120-element pumped microlaser array.
  • Figure 11 is a perspective view of a linear array spatial light modulator.
  • Figure 12 is a conceptual schematic diagram similar to Figure 1 of an embodiment of the invention, employing several of the modulators shown in Figure 11.
  • Figure 12A is an enlarged perspective view of a spatial light modulator in the same orientation in which it is shown in Figure 12.
  • Figure 13 is a block diagram illustrating an embodiment of the components of another imaging system.
  • Figure 14 is a block diagram illustrating a light shaping device.
  • Figure 15 is a block diagram showing the aspects of the display system which are applied to each single color laser source in the system depicted in Figure 13.
  • Figure 16 illustrates a saw tooth image scanning format.
  • Figure 17 illustrates a 2X saw tooth interlaced image scanning format.
  • Figure 18 illustrates a triangular image scanning format.
  • Figure 19 illustrates a 2X triangular image scanning format.
  • Figure 20 illustrates the saw tooth image format shown in Figure 16 for one band.
  • Figure 21 illustrates the 2X saw tooth format shown in Figure 17 for one band.
  • Figure 22 illustrates the triangular wave scanning format shown in Figure 18 for one band.
  • Figure 23 illustrates the 2X triangular wave pattern shown in Figure 19 for one band.
  • Figure 24 illustrates a saw tooth interleaved pattern for three bands.
  • Figure 25 illustrates a 2X triangle wave interlaced/interleaved scanning format for three bands.
  • Figure 26 illustrates a 2X saw tooth interlaced/interleaved scanning format for three bands.
  • Figure 27 illustrates a triangle wave interlaced/interleaved scanning format for three bands.
  • Figure 28 illustrates a triangle interlace/interleaved scanning format for three bands.
  • Figure 29 illustrates a saw tooth interleaved blended scanning format for three bands.
  • Figure 30 is a block diagram illustrating an embodiment of the components of another imaging system for step scanning.
  • Figure 31 is a diagram illustrating some of the features of a fiber optic converter.
  • Figure 32 is a block diagram illustrating one embodiment of an imaging system for implementing a pushbroom scan.
  • Figure 33 is a diagram of a linear fiber optic array for pushbroom scanning.
  • Figure 34 shows a light path of the laser beamlets traveling from a micolens array through a PLZT modulator.
  • Figure 35 is a block diagram illustrating the effect of a relay lens on a laser beamlet during a pushbroom scan.
  • Recent advances in diode laser-pumped solid-state lasers have made possible compact, efficient, visible, coherent microlaser sources. Applications requiring small size and low weight are one use for microlaser projection systems. Such applications can utilize the well developed near-IR diode laser technology as a pump source for rare-earth ion doped solid-state lasers, thereby facilitating the conversion of the near-IR radiation to coherent, narrow band, visible light. Alternatively, visible heterostructure diode lasers are also amenable to the disclosed display configuration.
  • Some embodiments of the present invention employ visible microlaser technology.
  • other laser sources may be used including heterostructure diode lasers.
  • the term "lasers” will be used herein to generally encompass suitable laser sources.
  • some embodiments utilize beamlets which are generated from a single laser beam so it should be understood that where appropriate the array of beams from an array of laser sources can be substituted with the beamlets from a single source and vice versa.
  • a red/green/blue (RGB) microlaser system consisting of three lasers or laser arrays, each operating at a fundamental color, is used for an efficient, high brightness, white light projection source for display applications.
  • the microlaser operation has been achieved at 650 nm, 530 nm, 470 nm, and 450 nm, as discussed below.
  • an array of 1200 lasers or 1200 beamlets is scanned horizontally in approximately 14.3 ms to attain a resolution of 1200 lines by 1400 pixels.
  • arrays containing fewer individual microlasers or beamlets can be used in a variety of multi-scan geometries.
  • a red, green and blue array of 120 microlaser elements or beamlets each are employed.
  • the arrays of light sources are scanned in two dimensions. With each horizontal scan 120 video lines are written, requiring 10 scans to complete the 1200 line image. While the arrays are scanned they can be intensity modulated by an electrical current applied to the individual diode laser pumping sources.
  • FIG. 1 An exemplary embodiment of the invention is shown in Figures 1 and 2.
  • a light generator microlaser array module 1 1 comprised of an array 12 of 120 red microlaser elements, an array 13 of 120 green microlaser elements, and an array 14 of 120 blue microlaser elements. Directly adjacent each microlaser array is equivalent pumping diode array
  • Video or image signals which control diode power, are applied to the pumping diodes through a cable 21.
  • the scanning light beams then pass through an imaging lens assembly 24, a speckle eliminator 25, a projection lens 26, and a projection screen 27.
  • the speckle eliminator 25 is a preferred element of the system, but it is not an essential element.
  • the system shown in Figure 1 includes a projection screen 27, which has certain parameters. As stated previously, that screen may be as large as 7.5 feet diagonal. It may be a flat screen or wall, or a concave screen. The system is suited to any type of projection surface including those typically used for motion picture projection systems.
  • the individual microlasers within a 120 element array can be intensity modulated at a rate of 490
  • the effective gray level and color of each pixel is determined by the amplitude of the diode current and the relative powers in the RGB beams.
  • Different scanning formats are accomplished with the polygonal scanner 22 which is configured with successively tilted facets.
  • the tilt angle between two facets is such that the projected image shifts during the polygon's rotation by 120 lines when the next horizontal scan is performed.
  • the tilt angles between two adjacent facets would be 0.6°.
  • Known techniques of diamond machining are sufficient to form the scanning polygon mirror 22.
  • a complete projection system based upon the above described technique accepts the outputs of three laser arrays, combines them, scans them, and projects them as a picture upon a large screen.
  • an optical train following the laser arrays comprises six principal elements. These elements include a dichroic prism combiner 31, the relay lens 23, the polygonal scanning mirror 22, the imaging lens 24, the speckle elimination element 25, and the projection lens 26. The final image is focused onto the projection screen 27.
  • the geometry of the dichroic prism combiner 31 of Figure 3 is arranged such that, when viewed from a prism output 32, the outputs from individual microlaser arrays are precisely registered one with respect to another.
  • the red array 12 is paired with and abuts against face 33 of the prism combiner 31.
  • the red microlaser output light beam follows path 34, 35, 36 to the output beam 32.
  • the green array 13 similarly abuts a face 37 of the prism.
  • the green microlaser output light beam follows path 38, 35, 36 to the output beam
  • the blue array 14 abuts a face 41 of the prism.
  • the blue microlaser output light beam follows a path 42, 43, 36 to the output beam 32.
  • faces 45, 47, 51, 52 and 53 of the dichroic prism are appropriately coated to reflect certain wavelengths and to pass others.
  • the face 45 reflects the red light waves while the faces 52 and 53 are transparent to red.
  • the locations of the red, green and blue inputs with respect to the prism and the structural geometry of the system are such as to allow maximum convenience in microlaser array accessibility.
  • the associated relay lens 23 produces an exit pupil of small diameter, matched with the size of and distance to a face of the polygonal scanning mirror 22.
  • the typical tilt-facet polygon scanner 22 which employs a total of twenty facets (two each at ten progressive angles) is illustrated in Figure 4.
  • the 20-sided scanner can be designed with groups of faces 61 and 62, each group of which exhibits ten discrete pyramidal angles, each specific angle being duplicated on diametrically opposed facets.
  • the facets in the first set of ten are designated 61 and the repeating set of ten are referred to with numeral 62.
  • This configuration allows consecutive facets of the scanner to step the picture by 10 percent of the overall picture height.
  • the radius of the polygon is on the order of 50 mm, while the speed of rotation required to achieve 70 frames per second is 1,200 rpm.
  • the imaging lens 24 (shown in Figure 1) has been designed to use the output of the polygonal scanning mirror 22, which is typically collimated, and to provide an exit pupil that is conjugate with the entrance pupil of projection lens 26.
  • This lens provides a color corrected diagonal field of about 40 degrees in conjunction with an exit pupil which is located approximately 200 mm beyond the image plane.
  • Compound lens arrangements are within the ordinary skill in the art and will not be described in detail here.
  • a layout for a 120-element individually addressed microlaser array is shown in Figure
  • a board 65 has circuitry 66 printed thereon which provides multiple connectors 67 for the video signals to be conducted to laser diode array 15. These diodes pump the microlasers in the array 12 to result in the emission of red output light to the surface 33 of the diachroic prism combiner 31. Mounted to the other side of the board 65 is a heat sink and a thermoelectric cooler (TEC) 71. When three such arrays (providing red, green and blue light beams) are mounted to the combining prism, they are integrated into a projection system which takes the form shown in Figures 6 and 7.
  • TEC thermoelectric cooler
  • FIGS. 1-10 These views of the system illustrate the three-dimensional relationship between system elements, namely, the microlaser arrays, the combining prism, the relay lens, the scanning polygon mirror, the imaging lens, the speckle elimination device, and the final projection lens.
  • a projector control card 73 to which the video signals are applied through an input 21
  • a diode driver card 74 connected by a cable 75 to the card 73. Cables 76, 77 and 78 connect the respective laser diode/microlaser modules to the driver card 74.
  • a chassis 81 also includes a power supply 82 and auxiliary power supply 83. When a laser source is used for video image projection, each individual pixel at the screen comprises a large number of scattering sources.
  • speckle a complex interference pattern which is called speckle.
  • Prior laser based projection systems have suffered from this problem of image speckle which is intrinsic to narrow-band laser sources.
  • speckle manifests itself as fine grain intensity fluctuations in the viewed image, the specific distribution of fluctuations rearranging itself in a random fashion whenever the viewer's head executes small lateral motions.
  • the visual effects of speckle detract from the aesthetic quality of an image and also result in a reduction of image resolution. Consequently, in the context of high resolution display systems, it is generally deemed essential that speckle be eliminated.
  • a flowing fluid diffuser comprises a pair of closely spaced glass plates between which a highly turbid fluid is caused to flow. Tests of this concept have been performed with a correction fluid suspension acetone. An example of such a product is "Liquid Paper” (a trademark of The Gillette Company). At modest flow rates, this technique results in complete elimination of speckle. However, it combines low transmission efficiency with the inconvenience of a pump and associated plumbing.
  • speckle eliminator When the particles suspended in a fluid diffuser are sufficiently small in size, speckle is eliminated in the absence of flow. This phenomenon is caused by Brownian motion of the scattering particles. As such, it leads to a simple and compact device which, in the conventional sense, has no moving parts.
  • a disadvantage of this type of speckle eliminator is that its transmission efficiency is limited, compared with what presently appears to be the best available system described below.
  • a screen with linear dimensions which are slightly greater than the intermediate image within the projection system is employed.
  • the screen is supported on springs, and caused to vibrate in a plane which lies perpendicular to the projection axis of the video image beam.
  • a conceptual example is shown in Figure 8.
  • a screen 25 is supported by spring elements 85 from an aperture plate 86, which is mounted to the chassis 81.
  • the nutation may be induced in the screen 25 by orthogonal electromagnets 87, 88.
  • the image beam passes through an opening 91 in the plate 86 and then through the speckle eliminator screen 25.
  • Motion relative to two orthogonal axes is induced in the screen 25, together with a 90- degree phase shift between those motions, in order to avoid periodic moments of zero velocity which would be associated with simple harmonic motion along a single axis.
  • the result is a non- rotating diffuser which undergoes rapid nutation, much in the manner of the contact surface of a orbital sander. Hence, all regions of the image are subjected to the same motion.
  • An excursion of 1 millimeter at 60 Hz provides a constant transverse velocity of about 20 cm sec "1 . This yields an inexpensive device which is barely larger in cross section than the imaging beam itself.
  • one type of microlaser suited to image projection typically is fabricated by a polishing wafer 94 of solid-state rare-earth doped gain medium so that two sides of the wafer are flat and parallel.
  • the thickness of the wafer 94 corresponds to the length of the laser cavity, which is typically on the order of 1 mm.
  • Appropriate dielectric coatings 95 and 96 are deposited directly to the polished surfaces to form the mirrors of a two-mirror standing wave cavity.
  • Near-IR diode lasers such as AlGaAs quantum well devices, are used to longitudinally pump the microlaser, as indicated by input 97.
  • the diode laser wavelength can be temperature- tuned to a strong absorption band of a rare-earth ion, thus allowing very efficient operation.
  • the planar uniformity of the flat-flat cavity is broken by pump beam 97, which deposits heat as it pumps the crystal. As the heat diffuses outward from the pumped volume, it forms a thermal waveguide that defines the transverse dimensions of the oscillating mode, typically 100-200 ⁇ m in diameter.
  • the output is indicated by reference numeral 101. If smaller mode sizes are required, convex curvatures can be imparted onto the microlaser surfaces.
  • One of the techniques employed to generate visible light from a microlaser is based on frequency doubling of the near-IR emission of an aluminum galium arsenide (AlGaAs) diode laser pumped neodymium ion (Nd 3+ ) doped device.
  • AlGaAs aluminum galium arsenide
  • Nd 3+ neodymium ion
  • the AlGaAs output is tuned to the 0.809 ⁇ m absorption transition of Nd 3+ , and lasing is achieved at 1.3 ⁇ m, 1.06 ⁇ m, and 0.9 ⁇ m.
  • visible light at 0.65 ⁇ m, 0.53 ⁇ m, and 0.45 ⁇ m is obtained.
  • red, green and blue laser output are achieved.
  • the specific techniques to generate the various colored laser beams are not relevant to this system invention.
  • frequency doubling can be accomplished with a single rare earth doped nonlinear material or with two adjacent materials, such as a rare earth doped crystal in combination with a second nonlinear crystal.
  • microlaser occupies only a small volume within a host wafer and that volume is pumped along an axis which lies perpendicular to the plane of the wafer, it becomes a simple matter to incorporate an array of microlasers within a single wafer.
  • array geometries of microlasers are limited only by characteristics of the pump diode laser arrays and by the transverse mode dimensions mentioned above.
  • microlaser arrays One approach for fabrication of microlaser arrays is to polish a slab or sheet of gain material flat and parallel with etalon parallelism tolerances. This slab is butt-coupled to a diode laser array, with laser action occurring at the positions of each diode laser pump.
  • This slab is butt-coupled to a diode laser array, with laser action occurring at the positions of each diode laser pump.
  • the smallest spot size, and hence the minimum center-to-center spacing of individual microlaser elements is limited by thermal diffusion and by the size of the resultant thermally induced index-waveguide. Even when the diode pump spots are extremely small, the thermal waveguide effect limits the spot size and center-to-center spacing to -100 ⁇ m.
  • the surfaces of the material can be modified such that the microlaser mode size is determined by surface curvatures and not by the pump- induced thermal waveguide effect.
  • the single element microlaser cavity design should be chosen to give a transverse mode diameter on the order of 20 ⁇ m.
  • a 20 ⁇ m mode diameter is achieved with a confocal resonator of length 300 ⁇ m (a confocal resonator requires convex surface/mirror radii of curvatures equal to the cavity length). Convex surfaces, as shown in Figure 10, reduce the lasing threshold. Indexes of refraction are different for different lasing materials, but that information is readily available as needed.
  • Each element within the array is a single mode diode laser with an output aperture of 1 x 20 ⁇ m and an emission bandwidth of less than 1 nm at output wavelengths of about 0.809 ⁇ m. These characteristics are well suited for pumping Nd 3+ doped microlasers. Also, such devices have been tested to 1 MHz amplitude modulation bandwidth with no sign of optical cross-talk between adjacent emitters.
  • a diode laser pump element 1 16 is aligned with each convex surface 1 15.
  • Each diode laser is individually modulated in intensity so that it pumps its associated microlaser with 0.809 ⁇ m energy 1 17, causing lasing action, and the appropriate wavelength output 121 (red, green or blue) at the appropriate image intensity is emitted.
  • the laser light so emitted is operated on as previously discussed in connection with the description of the system.
  • microlasers there are 120 microlasers within the laser material strip of 10 mm in length.
  • the center-to-center spacing between adjacent microlaser elements is in the range of 83 ⁇ m. It could be less, depending on the configuration of the elements of the system, even as small or smaller than about 25 ⁇ m spacing.
  • the thickness of the strip or the sheet 1 1 1 is on the order of 300 ⁇ m and the radius of curvature of each convex protrusion 1 15 is also on the order of at least 300 ⁇ m. This relationship, where the radius of curvature is at least equal to the length of the cavity, can be maintained to ensure small laser modes and stable laser action. As each microlaser is pumped, it emits a beam of approximately 20 ⁇ m diameter. This set of parameters is by way of example only. Another embodiment of the laser/modulator array module is shown in Figures 1 1, 12 and
  • FIG. 12A Figure 12 is quite similar to Figure 1, with the addition of a linear array spatial light modulator 131 of Figure 1 1.
  • the microlaser array employs spatial light modulators.
  • One suitable spatial light modulator is based upon the ceramic electro-optic material lead lanthanum zirconate titanate (PLZT). This material has been employed in light modulator applications such as for flash blindness goggles. Since the material is a ceramic, the fabrication technology is well developed so high yield, low cost devices can be realized.
  • One embodiment of the invention employs uses a PLZT modulator with a 9.0/65/35 composition (9% lanthanum and a 65:35 ratio of zirconate/titanate).
  • the dimensions of one embodiment of a PLZT device measures 150 ⁇ m in thickness by 1 mm in length and 27 mm in width to produce 64 linear array elements.
  • PLZT exhibits a large, fast electro-optic effect in the absence of a piezo-electric effect.
  • a PLZT compositional range between 8.8 and 9.65 percent lanthanum, with the remainder being a 65:35 ratio of lead zirconate to lead titanate respectively, exhibits a large, fast , quadratic electro-optic effect in the absence of a piezo-electric effect.
  • this material displays high transmission per unit length ( ⁇ 95%/mm) in the spectral region extending from ⁇ 450nm to ⁇ 670nm, the region of interest here.
  • This composition has 9% lanthanum and the remainder is a 65:35 ratio mixture of lead zirconate and lead titanate, respectively.
  • the linear array spatial light modulator 131 shown in Figure 11 may be made with the following characteristics, listed here only as an example. Thickness 133 of a wafer 132 is 0.15mm, its width 134 is 1mm, and its length 135 is 27mm. This wafer has 128 Cr/Au electrodes 136 which are 50 ⁇ m wide, with the pitch between electrodes of 250 ⁇ m. Photo-etched masks can be designed to allow for Cr/Au electrode patterns to be deposited directly onto the fabricated
  • PLZT material The use of masks in the deposition process eliminates the need for additional photo- or chemical etching steps while still allowing for high packing densities in a transverse configuration.
  • the electrodes are deposited on one side of the wafer and a ground plane 137 is deposited on the other side. Appropriate wire bonding techniques may be employed to connect electrical signals to each electrode. -!3-
  • Injected microlaser beams 141 from each microlaser element in an array, such as array 152, are 50 ⁇ m in diameter and their input polarizations are oriented at 45° to the applied electric field.
  • the red and blue microlaser outputs need phase retarders to achieve 45° polarization, while the green output is already polarized at 45°.
  • a polarization analyzer 142 is bonded to the output side of the modulator wafer 132 and its polarization at zero modulation voltage is oriented at 90° relative to the input polarization. Under these conditions, when no modulation voltage is applied to the electrodes 136 there is no light output from the microlaser array module. With the module dimensions given above, and the known electro-optic coefficients of PLZT, the half wave voltage (voltage required for intensity modulation from full ON to full OFF) is -70 V.
  • the polarization of the respective microlaser beamlet is rotated, resulting in polarization modulation in the wafer 132 of the video voltage signal.
  • the output of the module from the analyzer 142 is then amplitude modulated.
  • the microlaser array beams are simultaneously adjusted in amplitude by changing the voltages amplitudes applied to the electrodes 136 on each wafer 132.
  • FIG. 12 For completeness, the other image projection system elements will be called out.
  • the differences between Figure 12 and Figure 1 are in the microlaser array module 151 and its external connections.
  • input cable 161 In place of current driver video input 21, which directly modulated each laser pumping diode in arrays 15, 16 and 17 in Figure 1, input cable 161 is a power connection only.
  • all of the pumping diodes in arrays 155, 156 and 157 are on continuously, thereby continuously energizing each microlaser element in arrays 152, 153 and 154.
  • a voltage driven video input signal is employed in the Figure 12 embodiment, referred to generally by reference numeral 151.
  • a cable 158 is seen to be comprised of many wires 159, one connected to each electrode 136 on the wafer 132.
  • An external ground connection is made to a ground plane 137 by a wire 139.
  • individual ground connections are made to electrodes 136 by conventional wire bonding.
  • the output beams from the module 151 are then combined by such means as combiner 171, possibly the dichroic prism shown in Figure 3.
  • the laser beams then proceed through relay lens 163, are scanned as previously described by scanner 162, pass through an imaging lens 164, a speckle eliminator 165, a projection lens 166 and finally onto projection screen 167.
  • the modulation apparatus in the Figure 1 embodiment comprises the video or image input 21 and the laser diodes 15, 16 and 17.
  • the modulation apparatus in the Figure 12 embodiment comprises the image input 158, the wires 159, the wafer 132, and the electrodes 136.
  • the red, green and blue laser elements of Figure 1 are individually addressed in the manner that they are excited or energized by the modulation means.
  • the laser elements are continuously excited and it is the output beams that are individually addressed and modulated.
  • the combining element is shown as the dichroic prism 31, but other structures could be devised to accomplish the same result.
  • the unitary microlaser block 1 1 shown in Figure 1 may be made in separate spaced elements as shown in Figures 6 and 7. A different combiner would likely result in a different physical arrangement of the microlaser arrays and, of course, the mating spatial light modulators of Figure 12.
  • Figure 13 is a block diagram illustrating a display system using three laser light sources.
  • the system includes blue, green, and red laser light sources 202, 204 and 206, respectively. Alternatively, other members of laser light sources and other spectra may be used.
  • Each laser light source has a light shaping device 208, 210, 212 which receives the laser light from the laser light source and shapes it into the required line of light which is received by the associated microlens arrays 214, 216, 218.
  • the microlens arrays convert the received line of light into a specified number of approximately identical beamlets. The beamlets are then treated in a manner similar to that described for the arrays of lasers in the systems depicted in Figures 1 and 12.
  • the beamlets are received by modulators 220, 222, 224, which are capable of separately modulating each individual beamlet in response to an input control signal 226, 228, 230.
  • Three lenses 232, 234, 236 then direct the respective beamlets into the color combiner 238 which can be of the type of combiners described above with regard to Figure 1, element 31 and Figure 12, element 171.
  • the field lens one for the blue source, one for the green source, and one for the red source, work in combination with the collimating lens 306 to form a pupil on a polygon scanner 246. Because the color sources are not in a common beam path, the field lens also may provide for correction of chromatic aberrations.
  • the combiner 238 functions to precisely register each of the individual red, green, and blue beamlets with each other in the same manner as was described with reference to the individual microlaser array outputs with regard to Figures 1 , 3, 6, and 7 above.
  • the combining results in an output of beamlets, each of which comprises three input beamlets of each of the colors red, green, and blue.
  • the combined beamlets are then passed through a collimator lens
  • the collimator lens 242 directs the beamlets to the polygon scanner 244 which operates to scan the beamlets in a single dimension.
  • the polygon scanner 244 has identical facets which are aligned vertically.
  • the scanned beamlets are then directed to a second scanning apparatus 246 which scans the beamlets in a second dimension.
  • the polygon scanner 244 can be used to scan the beamlets in a horizontal or row direction while the second scanning apparatus
  • the second scanning apparatus 246 is used to scan the beams in a vertical or column direction.
  • the second scanning apparatus 246 can be in the form of a galvanometer or a feedback piezo-actuator.
  • the galvanometer may be of the type sold by Cambridge Technology, Inc., 23 Elm Street, Watertown, MA 02172.
  • the beamlets then pass through a reimager 248.
  • the reimager 248 focuses the collimated beam from the second scanning apparatus 246 to form an intermediate image.
  • a speckle eliminator 250 is located at the image plane (intermediate image) formed by the reimager 248.
  • the beamlets pass through projection optics 252 which relay and magnify this image onto a viewing screen (not shown).
  • the system can be used with a viewing screen that is configured for either rear or front projection.
  • a rear projection screen is partially transmissive and disperses the light in a forward direction. The image is then viewed from the side of the screen opposite the projector.
  • a front projection screen reflects the projected light and disperses it back toward the projector. The front projection screen is viewed from the side of the screen that the projector is located.
  • An incident laser beam 302 (such as from the blue, green, or red microlaser sources 202, 204, 206) is directed to a Powell lens 304.
  • a Powell lens is manufactured by Lasiris which is located at 2549 Ashby Street, St-Laurent, Quebec Canada HR4 2K3.
  • the Powell lens 304 is a one-piece BK-7 glass lens with an aspheric tip which generates a line of light. The dimensions of the line generated vary in length when viewed from different distances from the Powell lens 304 and in one embodiment, has a fan angle of approximately 20°.
  • the resulting beam fan from the Powell lens 304 is a semi-flat top along the length of the line and has the same beam profile along its width.
  • the line is received by a collimating lens 306.
  • the collimating lens may be a system of lenses which collimate the line in preparation for sampling by the microlens array 214, 216, 218.
  • the microlens arrays 214, 216, and 218 may be molded acrylic microlenses such as are available from Adaptive Optics Associates, located at 54 Cambridge Park Drive, Cambridge, MA 02148.
  • the microlens array has three rows with each row having sixty-six lens elements which can create a total of 198 beamlets. In one embodiment, only one of the rows of lens elements is utilized and only sixty-four of the produced beamlets are used. There are numerous variations of numbers of rows and lens elements that may be utilized.
  • Figure 15 is a conceptual block diagram showing aspects of the display system depicted in Figure 13 which are applied to each single color laser source (e.g. sources 202, 204 and 206 of Figure 13) in the system.
  • the laser source 402 is generally a source of optical radiation. The radiation may be of the red, blue, or green spectrum or other colors, including infrared, could be utilized for particular applications.
  • Figure 15 are referred to as the beam shaping device 400.
  • separate beam shaping devices are utilized for each color in this system, i.e., red, green, and blue for the system depicted in Figure 13.
  • multiple laser beams from multiple sources may be combined into a single laser beam 404.
  • a line converter 406 converts the laser beam into a line of radiation 408.
  • the line converter 406 can be in the form of a Powell lens, a holographic optical element, a defractive optical element, or other lens systems.
  • the line of radiation 408 is then collimated by a collimating optical system 410.
  • the collimated light is directed to a beam sampler which divides the collimated line of optical radiation into a plurality of beamlets 416.
  • One embodiment of the beam sampler is a microlens array as was described above.
  • An aperture array 418 may be included to more clearly define the beamlets.
  • the beamlets are received by a linear spatial light modulator ("SLM") array 420.
  • the SLM array 420 includes a plurality of modulator elements, and can include a modulator element for each beamlet.
  • the modulator elements are responsive to a control signal such as a video signal for modulating each of the beamlets.
  • the SLM array can include be a PLZT modulator as described above.
  • a video modulation system 422 receives video or control signals representative of a predetermined image in a video or other format. The video modulation system then supplies the signals that control the modulation of the SLM in accordance with video or control signals and the scanning format of the system.
  • Direct analog modulation of the PLZT device can be utilized.
  • Gray scale rendering can be achieved using the PLZT modulator described above by using a pulse width modulation (PWM) technique, in which the varying spatial width of each pixel on the screen is integrated by the human eye and is perceived as varying levels of intensity. This is achieved by driving the PLZT device to its full intensity at each pixel and varying the time width of each pulse to obtain the desired intensity effect.
  • PWM pulse width modulation
  • One system to drive the PLZT device utilizes a video memory board and interface boards that provide the modulation signals for the PLZT device drivers.
  • the video memory board can be configured to receive 8-bit serial video data and convert it into parallel data in the required readout format.
  • the interface board which converts this information into the pulse width modulation (PWM) signals.
  • PWM pulse width modulation
  • the data from the interface board is a TEL-level PWM format that is passed to the PLZT device driver electronics which provides the required voltage levels needed to drive the PLZT device.
  • the PLZT device drivers can, for example, consist of a bank of amplifiers, such as those which were originally designed to drive CRTs.
  • Figures 16-29 illustrate various methods ("formats") for scanning an image onto a display screen.
  • the modulated beamlets are applied in parallel to the display screen.
  • An image is created when all of the lines in the frame are written.
  • the scanning of the beamlets is effected by, for example, the scanning polygon 22 in the system described in connection with Figure 1 and by the combined effects of the scanning polygon 244 and the second scanning apparatus 246 in the system described in connection with Figure 13.
  • the number of modulated beamlets applied in parallel to the screen can range from two up to an extremely large number in excess of 200 depending upon the characteristics required of the system.
  • a frame can be subdivided into bands.
  • a band is defined as a group of adjacent lines. Lines in multiple bands can be written simultaneously.
  • Figure 16 represents a saw tooth format wherein the lines within each band are written sequentially in order from top to bottom. In other words, a first line in every band is simultaneously written, then the second line in every band is simultaneously written and so on until all of the lines in the bands have been written which completes a single frame.
  • This scanning process proceeds in parallel for each of the bands being scanned.
  • the scale along the horizontal axis is in terms of line periods and the numbering along the vertical axis defines the bands.
  • the representation in the upper left corner of the figure indicates that each of the bands contains ten lines with the first darkened dot representing the first line of the first band and the second darkened dot representing the first line of the second band.
  • Figure 17 represents a 2X saw tooth interlaced format.
  • the odd lines in each band are written sequentially beginning at the top of the band (first line) during the first half of the frame.
  • the scanned beam then returns to the top of each band and writes the even lines sequentially beginning at the top during the second half of the frame.
  • the process then repeats for each frame.
  • the display includes 480 lines divided into sixteen bands of thirty lines each. Each frame equals (is written in) 16.66 milliseconds.
  • the second scanning apparatus 246 controls which line is being written while the line period is controlled by the scanning polygon 244.
  • different numbers of bands, lines, and frame periods can be utilized.
  • Figure 18 illustrates a triangular scan format.
  • the odd lines in each band are written from the top (line 1) sequentially in the first half of the frame period, and the even lines are written from the bottom line (line 10) in an ascending order to the top of the screen in a second half of the frame period.
  • the scan direction may be easily reversed, and the even lines can be scanned before the odd lines.
  • the format depicted in Figure 18 has n bands with each band having ten lines.
  • Figure 19 illustrates a 2X triangular scan format.
  • each beamlet starts out at the first line of a band.
  • the beamlet then skips three lines and writes the fourth line.
  • the beamlet reaches the bottom of the band, the beamlet reverses its progression up the band.
  • the triangular pattern is repeated twice so that upon the completion of two triangular passes all of the lines have been written.
  • An example of the 2X triangular scan format illustrating the order in which the lines are written is provided below with reference to Figure 23.
  • the scanning pattern illustrated in Figure 19 depicts 10 lines in a band.
  • Figures 20-29 illustrate the beamlet progression on the screen lines during the scanning process for various formats.
  • the time for each of the figures is shown along the horizontal axis in units of line periods and the vertical axis shows the position of a line within a band.
  • Figures 20-29 illustrates the scanning process for two frames X and Y and the first line period of a third frame. Immediately to the right of the line number is a value which indicates the number of times a line is written during the two frames X and Y. A line scanned during a line period is indicated by a one in the box corresponding to the indicated time and line. If the box is empty, that line is not being written during that line period.
  • For the non-interleaved scanning formats such as are illustrated in Figures 20, 21, 22 and 23 only one band is shown to illustrate the scanning operation. AU of the bands of these formats are written identically. These same scanning formats correspond to the formats described with reference to Figures 16-19 above.
  • Figure 20 illustrates a saw tooth scanning format.
  • the first beamlet In a frame X the first beamlet writes line 1 and progresses to line 10 of the band progressively writing each line in the band in succession. In the next frame Y, the first beamlet repeats the scanning process starting again at line 1. Each beamlet for each band operates in a similar manner.
  • Figure 21 illustrates the 2X saw tooth (interlace) scanning format.
  • a first beamlet writes line 1 and progressively writes every odd line until line 9. The first beamlet then restarts at line
  • Figure 22 illustrates the triangle wave (interlace) scanning format.
  • the laser beamlet writes every other line until line 9. Then, starting at the bottom of the band, the laser beamlet switches direction and proceeds to write lines 10 to line 2 skipping every other line.
  • the pattern is repeated. Beamlet writes to each of the other bands in a similar manner.
  • Figure 23 illustrates the 2X triangle wave scanning format. This is the same scanning format illustrated in Figure 19.
  • the pattern for beamlet 1 starts at line 1, and writes every fourth line.
  • the sequence of lines written are: 1, 5, 9, 7, 3, 2, 6, 10, 8 and finally 4.
  • the beamlet repeats the same scanning pattern.
  • the saw tooth interleaved format operates identically to the simple saw tooth format illustrated in Figure 21 during the first frame period.
  • the beamlets continue down into the band immediately below.
  • the first beamlet scans an omitted (not displayed) band and the second beamlet adjacent to the first beamlet scans the first (displayed) band.
  • the first beamlet scans the first band and the second beamlet scans the second band. The pattern then repeats.
  • Figure 25 illustrates the 2X triangle wave interlaced/interleaved scanning format.
  • the beamlets write every fourth line.
  • each beamlet In the first half of the frame X, each beamlet writes in a first band and in the second half of the frame X, each beamlet writes in the adjacent band.
  • the operation repeats. For example, starting at line 1, a beamlet writes to the omitted band. The beamlet then skips four lines and writes to line 5 followed then by line 9. The beamlet then moves to band one where it writes to lines 13, 17 and 20. The beamlet then reverses its progression and writes lines 16, 12, 8 and 4. The beamlet restarts the pattern beginning at line 1.
  • Figure 26 illustrates the 2X saw tooth interlaced/interleaved scanning format.
  • the first beamlet writes the odd lines in the omitted band starting at line 1 during the first half of a frame period and the second beamlet writes the odd lines in the first band starting at line 10.
  • the first beamlet writes the even lines in the first band and the second beamlet writes the even lines in the second band.
  • the beamlet repeats the pattern.
  • Figure 27 illustrates the triangle wave interlaced interleaved scanning format.
  • each beamlet writes every other line in a descending pattern across two adjacent bands during a first frame X and then writes every other line in an ascending order across two bands in a second frame Y.
  • a first beamlet in a frame X begins writing line 1 of an omitted band and then writes to every other line continuing down into the adjacent band.
  • the first beamlet begins by writing the last line of band 1 and then writes every other line in an ascending order ending at the first line of the omitted band at the end of the frame Y.
  • the second beamlet follows a similar pattern spanning the first and second bands and writing only to the even numbered lines. That pattern is repeated for all of the beamlets with the first and last bands not being displayed.
  • Figure 28 illustrates the 2X triangle interlaced/interleaved scanning format.
  • a beamlet starting at line 1 progresses to line 19 writing every fourth line.
  • the beamlet writes to the lines 1, 5, 9, 13, 17 and then 19.
  • the beamlet writes to the lines 4, 8, 12, 16 and
  • FIG. 29 illustrates the saw tooth interleaved blended scanning format.
  • the saw toothed interleaved blended format resembles the saw tooth interleaved format (shown in Figure 20) but differs in that during the second frame period, the vertical scanning restarts at 50% (half) of the scanning range of the beamlet.
  • a first beamlet scans an omitted band and a second beamlet scans the bottom half of the first band.
  • the first beamlet scans the top half of the first band and the second beamlet scans the top half of the second band.
  • the first beamlet writes the first band sequentially from top to bottom and the second beamlet writes the second band sequentially from top to bottom.
  • the pattern then repeats.
  • a beamlet writes to lines 1 through lines 10.
  • frame Y the beamlet writes lines 6 through 15. It may be desirable in certain circumstances to scan in a step like manner using a block of pixels.
  • FIG. 30 is a block diagram of the components of such a system showing only the components for a single color with identical components being used for the other colors as in the systems described above.
  • some of the elements previously described for such display systems as in Figure 13 have been omitted for clarity and like elements are identified by the same reference numbers as in Figure 13.
  • the microlaser source 204 generates a (green) laser beam that passes through the beam shaping device 400 that generates the beamlets as described above.
  • the modulator 222 modulates each of the beamlets which then enter a converter 602.
  • the converter 602 may be a fiber optic converter that has the same number of fibers as the number of modulator elements in the spatial light modulator 222. Each fiber is aligned with a modulator element so that the light traveling through that element is captured by the fiber. The fiber then transmits the light from the modulator 222 to the other end of the fiber. The ends of the fibers are grouped into a rectangular array, thereby creating a block of pixels.
  • the reformatted beamlets are then collimated by a collimating apparatus 604 which operates in a manner similar to that of the collimating lens 242 of Figure 13.
  • the collimator lens 604 collimates the optical beams from the output of the fiber optic converter 602 and forms a pupil in an acousto-optic or electro-optic scanner 606.
  • the acousto-optic scanner 606 scans the beams in a direction opposite to the scanning direction of the polygon scanner 244.
  • the scanner 606 scans the beams at the same velocity as the polygon scanner 244, thereby having the ability to effectively stop or freeze the display of laser beamlets on the screen.
  • the scanner 606 only stops the scan for a brief moment and then allows the polygon scanner 244 to effectively jump the scan to the position of the next block of pixels to be displayed. In this manner, the array of pixels steps across the frame until a row is completely written. Then, when the next facet of the polygon mirror comes around the process is repeated for the next group of lines.
  • each color red, green, and blue
  • each color can be provided with a separate scanner 606.
  • the color combiner 238 comes after the scanner 606.
  • the polygon scanner 244, the galvanometric scanner 246, the reimager lens 248, the projection lens 252, and the screen operate in the same manner as was described above.
  • FIG 31 is a schematic diagram illustrating some of the features of the fiber optic converter 602.
  • Each fiber optic cable 614 in the converter receives the light output from an individual element of the modulator 222 at an end 610. The light is transmitted along the cable 614 to an output end 612.
  • the output ends can be arranged in the desired format and with the desired spacing required by the system. In the example shown in the figure, a 3x3 block of pixels is created by the arrangement of the output ends and the block of pixels 613 is then stepped across the frame as was described above.
  • FIG 32 is a block diagram illustrating one embodiment of the imaging system for implementing a pushbroom scan.
  • This scanning technique is a variation of the step scan approach (shown in Figure 30 and 31), where a rectangular array of pixels at the output of the converter 602 is a linear array 1 pixel wide by n pixels long.
  • the acousto-optic or electro-optic scanner 606 is not needed.
  • the conversion process from a widely spaced array of pixels to a closely space linear array of pixels can be accomplished in one of two ways. First, as described above, a fiber optic converter can be used as shown in Figure 33.
  • FIG 33 is a schematic diagram of a linear fiber optic array for pushbroom scanning.
  • the pushbroom scanning array is similar to the converter 602 illustrated in Figure 31.
  • Each fiber 614 receives the light output from a single element of the modulator 222 at an end 610.
  • the fibers transmit the received light to an output end 612 with each of the output ends arranged in a linear array.
  • FIG. 34 Another embodiment of the invention uses a microlens array 702, a field lens 704, and a relay lens 706 as shown in figures 34 and 35 to generate the linear array.
  • Figures 34 and 35 illustrate in further detail selected portions of this system.
  • Figure 34 shows a light path of the laser beamlets traveling from the microlens array 214 through the PLZT device. The light output from each element of the PLZT device is received by the microlens array 702 which recollimates the light.
  • the field lens focuses the output light beams from the microlens array 702 onto the pupil of the relay lens 706 shown in Figure 35.
  • the relay lens 06 demagnifies this array and relays the pixel plane to the input of the collimator lens 604 in Figure 32.
  • the collimator lens 604, the color combiner 238, the polygon scanner 244, the galvanometric scanner 246, the reimager lens 248, and the projection lens 252 are the same as have previously been described.
  • additional laser sources and modulators could be used.
  • one or more of the laser sources may produce non-visible laser light, such as infrared radiation through night-vision goggles.
  • many of the elements of the various systems described herein can be replaced by equivalent elements which accomplish the same objective.
  • various sources of laser light can be used as can different lens arrangements. Therefore, the scope of this invention should not be limited by the examples provided.

Landscapes

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

Abstract

L'invention concerne un système d'affichage qui comporte des sources de lumière laser rouge, verte et bleue ainsi que des dispositifs de mise en forme de la lumière, qui reçoivent la lumière laser provenant des sources de lumière laser et mettent en forme la lumière pour créer plusieurs petits faisceaux à peu près identiques. Les petits faisceaux sont modulés individuellement; on combine les petits faisceaux ainsi modulés. Le produit de cette combinaison représente des petits faisceaux dont chacun comprend trois petits faisceaux d'entrée de couleur rouge, verte et bleue, respectivement. On peut ensuite balayer les petits faisceaux ainsi produits sur un écran d'affichage.
PCT/US1997/021545 1996-11-27 1997-11-26 Systeme d'affichage a balayage par faisceaux laser multiples WO1998024240A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU74128/98A AU7412898A (en) 1996-11-27 1997-11-26 Multi beam laser scanning display system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US3196796P 1996-11-27 1996-11-27
US60/031,967 1996-11-27

Publications (2)

Publication Number Publication Date
WO1998024240A1 true WO1998024240A1 (fr) 1998-06-04
WO1998024240B1 WO1998024240B1 (fr) 1998-08-06

Family

ID=21862377

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1997/021545 WO1998024240A1 (fr) 1996-11-27 1997-11-26 Systeme d'affichage a balayage par faisceaux laser multiples

Country Status (2)

Country Link
AU (1) AU7412898A (fr)
WO (1) WO1998024240A1 (fr)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2000062538A1 (fr) * 1999-04-13 2000-10-19 Koninklijke Philips Electronics N.V. Systeme d'affichage avec elements electroluminescents
WO2002031575A2 (fr) * 2000-10-11 2002-04-18 Silicon Light Machines Procede et appareil de diminution de la granularite laser
EP1361753A2 (fr) 2002-05-03 2003-11-12 Hewlett-Packard Company Projecteur avec optiques de balayage
WO2004002165A2 (fr) * 2002-06-19 2003-12-31 Seos Limited Procédé de projection laser d'images et projecteur laser
EP1411732A2 (fr) * 2002-10-16 2004-04-21 Eastman Kodak Company Systèmes d'affichage utilisant des sources lumineuses laser organiques
EP1292134A3 (fr) * 2001-08-27 2004-08-18 Eastman Kodak Company Système de projection laser
US6785001B2 (en) 2001-08-21 2004-08-31 Silicon Light Machines, Inc. Method and apparatus for measuring wavelength jitter of light signal
WO2006045381A1 (fr) * 2004-10-26 2006-05-04 Rheinmetall Defence Electronics Gmbh Systeme de vision
CN100451817C (zh) * 2002-12-03 2009-01-14 惠普开发有限公司 具有对准光学器件和电子设备的投影仪
GB2456170A (en) * 2008-01-07 2009-07-08 Light Blue Optics Ltd Holographic image display systems
CN101120284B (zh) * 2005-02-25 2010-05-19 松下电器产业株式会社 二维图像形成装置

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0488903A2 (fr) * 1990-11-30 1992-06-03 Sony Corporation Dispositif d'affichage d'image couleur à faisceaux laser
US5283694A (en) * 1992-09-21 1994-02-01 Frady Richard A Line projector lens
WO1995010159A2 (fr) * 1993-10-04 1995-04-13 Laser Power Corporation Systeme et procede de projection d'images a haute resolution employant des lasers
EP0696875A2 (fr) * 1994-08-09 1996-02-14 DEUTSCHE FORSCHUNGSANSTALT FÜR LUFT- UND RAUMFAHRT e.V. Dispositif pour produire une image
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

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0488903A2 (fr) * 1990-11-30 1992-06-03 Sony Corporation Dispositif d'affichage d'image couleur à faisceaux laser
US5283694A (en) * 1992-09-21 1994-02-01 Frady Richard A Line projector lens
WO1995010159A2 (fr) * 1993-10-04 1995-04-13 Laser Power Corporation Systeme et procede de projection d'images a haute resolution employant des lasers
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
EP0696875A2 (fr) * 1994-08-09 1996-02-14 DEUTSCHE FORSCHUNGSANSTALT FÜR LUFT- UND RAUMFAHRT e.V. Dispositif pour produire une image

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6583912B1 (en) * 1999-04-13 2003-06-24 Koninklijke Philips Electronics N.V. Display system with light-emitting elements
JP2003521722A (ja) * 1999-04-13 2003-07-15 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ 発光素子を有する表示システム
WO2000062538A1 (fr) * 1999-04-13 2000-10-19 Koninklijke Philips Electronics N.V. Systeme d'affichage avec elements electroluminescents
WO2002031575A2 (fr) * 2000-10-11 2002-04-18 Silicon Light Machines Procede et appareil de diminution de la granularite laser
WO2002031575A3 (fr) * 2000-10-11 2003-05-15 Silicon Light Machines Inc Procede et appareil de diminution de la granularite laser
US6785001B2 (en) 2001-08-21 2004-08-31 Silicon Light Machines, Inc. Method and apparatus for measuring wavelength jitter of light signal
EP1292134A3 (fr) * 2001-08-27 2004-08-18 Eastman Kodak Company Système de projection laser
EP1361753A2 (fr) 2002-05-03 2003-11-12 Hewlett-Packard Company Projecteur avec optiques de balayage
US7164451B2 (en) 2002-05-03 2007-01-16 Hewlett-Packard Development Company, L.P. Projector having scanning optics
EP1361753A3 (fr) * 2002-05-03 2004-01-07 Hewlett-Packard Company Projecteur avec optiques de balayage
US7184104B2 (en) 2002-05-03 2007-02-27 Hewlett-Packard Development Company, L.P. Projector having scanning optics
WO2004002165A3 (fr) * 2002-06-19 2004-12-29 Seos Ltd Procédé de projection laser d'images et projecteur laser
GB2395084B (en) * 2002-06-19 2005-10-12 Seos Ltd A method for laser projection of images and a laser projector
WO2004002165A2 (fr) * 2002-06-19 2003-12-31 Seos Limited Procédé de projection laser d'images et projecteur laser
EP1411732A2 (fr) * 2002-10-16 2004-04-21 Eastman Kodak Company Systèmes d'affichage utilisant des sources lumineuses laser organiques
EP1411732A3 (fr) * 2002-10-16 2007-05-30 Eastman Kodak Company Systèmes d'affichage utilisant des sources lumineuses laser organiques
CN100451817C (zh) * 2002-12-03 2009-01-14 惠普开发有限公司 具有对准光学器件和电子设备的投影仪
WO2006045381A1 (fr) * 2004-10-26 2006-05-04 Rheinmetall Defence Electronics Gmbh Systeme de vision
US8348440B2 (en) 2004-10-26 2013-01-08 Rheinmetall Defence Electronics Gmbh Vision system
CN101120284B (zh) * 2005-02-25 2010-05-19 松下电器产业株式会社 二维图像形成装置
GB2456170A (en) * 2008-01-07 2009-07-08 Light Blue Optics Ltd Holographic image display systems
WO2009087358A1 (fr) 2008-01-07 2009-07-16 Light Blue Optics Ltd. Systèmes d'affichage d'image holographique
GB2456170B (en) * 2008-01-07 2012-11-21 Light Blue Optics Ltd Holographic image display systems

Also Published As

Publication number Publication date
AU7412898A (en) 1998-06-22

Similar Documents

Publication Publication Date Title
US6154259A (en) Multi-beam laser scanning display system with speckle elimination
US5990983A (en) High resolution image projection system and method employing lasers
US5534950A (en) High resolution image projection system and method employing lasers
US6351324B1 (en) Laser imaging system with progressive multi-beam scan architecture
Amm et al. Optical performance of the grating light valve technology
JP4853033B2 (ja) 光走査装置及び画像表示装置
US6064423A (en) Method and apparatus for high resolution three dimensional display
US7701412B2 (en) Apparatus for and method of scaling a scanning angle and image projection apparatus incorporating the same
US5185660A (en) Actuated mirror optical intensity modulation
US6577429B1 (en) Laser projection display system
US8643928B2 (en) Illumination systems for visual displays
US5402184A (en) Projection system having image oscillation
EP0573615B1 (fr) Appareil de projection lumineuse
JP5673544B2 (ja) レーザー投射装置
JP4084713B2 (ja) ディスプレイ装置
KR20080090387A (ko) 형광 스크린을 이용하는 주사 빔 디스플레이 시스템용 광학설계
JPH07506220A (ja) 垂直キャビティ・面発光レーザアレイディスプレイシステム
AU722995B2 (en) Laser video display system and method
GB2414127A (en) Time sequential colour projection
JPH06138499A (ja) 直接網膜スキャン・ディスプレイ
US5687020A (en) Image projector using acousto-optic tunable filter
WO1998024240A1 (fr) Systeme d'affichage a balayage par faisceaux laser multiples
JP5304839B2 (ja) 光走査装置及び画像表示装置
Lee et al. Laser TV for home theater
JP2002055296A (ja) 光走査装置およびそれを用いた投射型表示装置

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE GH HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK SL TJ TM TR TT UA UG UZ VN YU ZW AM AZ BY KG KZ MD RU TJ TM

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): GH KE LS MW SD SZ UG ZW AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase