Background
Recent developments in digital imaging include the use of linear arrays as one-dimensional spatial light modulators. Images formed using linear arrays are produced one line at a time and then scanned across a surface for display or printing. Linear arrays have been recognized to have some inherent advantages over two-dimensional liquid crystal display devices (LCDs) and digital micromirror display devices (DMDs) that use planar spatial light modulators, including the ability to achieve higher resolution, reduce cost, and simplify illumination optics. In particular, where high color saturation, optimized color gamut, and good light intensity are emphasized, linear arrays of electromechanical grating devices are particularly well suited for use with laser light sources and are believed to be superior in many respects to their two-dimensional counterparts used to modulate laser light. For example, Grating Light Valve (GLV) linear arrays, described in Bloom et al, U.S. Pat. No.5311360, published 5/10 1994, entitled "Method and apparatus For Modulating A Light Beam", are an early linear array that provides a useful solution For high brightness imaging using laser sources. U.S. patent No.5982553 to Bloom et al, published on 9.11.1999, entitled "Display device incorporating One-Dimensional grading Light-Valve Array" ("Display device employing One-Dimensional Grating Light Valve Array"), discloses a Display device that modulates Light by using a diffractive linear Light Valve Array of an electromechanical Grating device.
Recently, U.S. patent No.6307663, issued to Kowarz at 23/10/2001 and entitled "Spatial Light Modulator with conformal Grating Device", describes an electromechanical conformal Grating Device comprising strip-like elements suspended over a substrate by a periodic sequence of intermediate supports, the electromechanical conformal Grating Device being operated by electrostatic actuation such that the strip-like elements conform to the support substructure, thereby forming a Grating. The' 663 device has been known for some recent time as a conformal GEMS device, which stands for grating electromechanical system. Conformal GEMS devices have many attractive features. It provides high speed digital light modulation with high contrast and high efficiency. In addition, in a linear array of conformal GEMS devices, the active area is relatively large and the grating period is oriented perpendicular to the direction of the array. This orientation of the grating period causes the diffracted beams to be separated in close proximity to the linear array and to remain spatially separated throughout most of the optical system. When used with a laser source, the GEMS device provides excellent brightness, speed, and contrast, and can provide higher resolution than using a planar or two-dimensional spatial light modulator. An example of a Display System using GEMS modulation is disclosed in U.S. Pat. No.6411425, published 25/6/2002, entitled "Electromechanical Grating Display System With spatial separation light Beams", by Kowarz et al.
With the advent of lower cost laser devices, there has been considerable interest in using lasers in display and printing applications. As a few of the many examples: tang, U.S. Pat. No.6128131, published on 3.10.2000, entitled "scalable inclined Flat-Panel Projection Color Display", discloses an inclined Projection Color Display using a laser source; U.S. patent No.6031561 to Narayan et al, published 2.29.2000, entitled "printing system providing a Light source Of Different Wavelengths", discloses a printing apparatus that uses laser Light to expose a photosensitive medium. Continued development in low-cost semiconductors and solid-state lasers is expected to make the interest in imaging applications such as scanning, recording, etc. that utilize laser light as a light source even higher.
Although there are some promising developments in laser performance, there is still considerable room for development. In display applications, there are practical limitations, for example, in the case of forming an image using three or more light sources having different wavelengths. Lasers with appropriate wavelengths for display applications, particularly in the blue and green spectral regions, are difficult to obtain or expensive. In printing applications, different wavelength sets are required depending on the photosensitive response characteristics of the photosensitive medium. Printing applications generally require higher resolution and overall uniformity than in display or projection applications.
To accommodate the need for low cost laser sources with the ability to produce a wide range of wavelengths, laser arrays using organic materials have been developed. U.S. Pat. No.6111902, published at 29.8.2000, entitled "Organic Semiconductor Laser", by Kozlov et al; U.S. Pat. No.6160828, published 12.12.12.2000, entitled "Organic Vertical-cavity surface-Emitting Laser", was proposed by Kozlov et al; U.S. patent No.6396860, published on 28.5.2002, entitled "Organic Semiconductor Lasers", filed by Kozlov et al, and U.S. patent No.6330262, published on 11.12.2001, entitled "Organic Semiconductor Lasers", filed by Burrows et al, disclose types of Vertical Cavity Surface Emitting Lasers (VCSELs) using Organic materials. Co-pending U.S. patent publication No.0171088 to Kahen et al, published at 21.11.2002, entitled "Inconent Light-Emitting Device Apparatus for driving Vertical Laser Cavity", and European patent application No.03075214.1, entitled "organic Vertical Cavity-Locked Laser Array Device", filed 23.1.2003, also disclose VCSELs having organic-based gain material and Emitting in the visible wavelength range. Organic-based gain materials have the advantage of lower cost due to their typically amorphous shape when compared to gain materials (organic or inorganic materials) that require high crystallinity. In addition, lasers based on organic amorphous gain materials can be grown in large areas without creating large regions of single crystal material; thus, the organic VCSEL array can be scaled to any size. Due to their amorphous nature, organic VCSEL arrays can be fabricated on a variety of different inexpensive substrates, such as glass, soft plastics, and silicon, and are easier to detect than conventional semiconductor lasers. Notably, the organic VCSEL array is capable of emitting over the entire visible range. The pumping of light can be accomplished using low cost incoherent light sources that are readily available, such as LEDs.
The nature of many organic VCSEL arrays can cause problems when they are applied in imaging applications, especially where linear spatial light modulators are used. For example, in practice, the aspect ratio of high-energy organic VCSEL arrays is generally rectangular, rather than linear. Thus, where higher light throughput is desired, aspheric illumination optics are required to properly shape the illumination beam for the linear spatial light modulator.
A more important issue is related to the spatial characteristics of the light beam emitted from the VCSEL. The output beam characteristics depend largely on which of the two configurations is used. Referring to fig. 1a, a first structure, referred to as an "out-of-phase structure", is shown. In the plan view of fig. 1a, a representative portion of a VCSEL array 100 is shown, including an arrangement of individual VCSEL emitting elements 102 and 103. In the hetero-phase structure, the interleaved VCSEL emissive elements 102 have one phase; the VCSEL emitting elements 103 adjacent thereto, indicated by shading, have opposite phases. By contrast, FIG. 1b shows another "phase locked" configuration of the VCSEL array 100. In this phase-locked configuration, each VCSEL unit has the same phase. The VCSEL emitting elements 102 and 103 in fig. 1a and 1b are arranged inside the VCSEL array 100 so that the symmetry axes are the horizontal and vertical axes. The axis of symmetry may be any axis in practice.
Referring to fig. 2a, there is shown a spatial structure of light emitted by the VCSEL array 100 in the out-of-phase structure of fig. 1 a. Here, instead of providing a single beam of light due to the desire for simplified processing of the optical modulation assembly, the VCSEL array 100 emits four first order lobes 110a, 110b, 110c, and 110 d. Lobes 110a-110d have unequal height-to-width ratios, shown approximately in FIG. 2 a; the height of each lobe 110a-110d corresponds approximately to the length L of the VCSEL array 100 shown in figure 1 a. Each lobe 110a-110d is assigned a pair of coordinates as a reference. In addition, higher order lobes are also transmitted; however, these higher order lobes contain only a small fraction of the emitted light, which can be ignored for first order approximation. At some distance d near the VCSEL array 100, lobes 110a and 110c overlap, as shown by shaded overlap region 112 a. Referring to fig. 2b, the same spatial arrangement of light beams is shown as it appears in fig. 2a, but at a distance 2d from the VCSEL array 100. Here, lobes 110a-110d have been separated farther apart, have not overlapped, and have become slightly more rounded in aspect ratio. It can be readily appreciated that splitting the emitted light into lobes 110a-110d requires customization of the beam shaping optics in the image modulation mechanism of the imaging device.
The phase-locked structure provides a more conventional laser beam, as opposed to the lobe arrangement of the out-of-phase structure. Referring to fig. 3a, the central lobe 110e now contains a relatively high ratio of emitted light, additional light in the first order lobes 110a-110d and only a small amount of light (not shown) in the higher order lobes. At a short distance from the VCSEL array 100, the central lobe 110e overlaps both the first order lobes 110a and 110c in overlap region 112a, and overlaps first order lobes 110a and 110c in overlap regions 112b and 112c, respectively. At twice the distance from the VCSEL array 100, the overlapping regions 112b and 112c are reduced in area and may disappear as shown in figure 3 b.
Thus, while VCSEL arrays have shown some promise as light sources to be modulated by electromechanical grating devices, considerable obstacles are believed to remain. As mentioned above, VCSEL arrays are capable of providing a high energy aspect ratio range, generally different from the aspect ratio required to illuminate an electromechanical grating device, necessitating a certain trade-off. More notably, the spatial characteristics of the modulated light beam may be relatively complex and different depending on whether an out-of-phase or phase-locked mode of operation is employed. These differences distinguish VCSEL laser arrays from conventional semiconductor laser sources and thus a solution is needed to cope with the aspect ratio and spatial content of the illumination beam emitted by the VCSEL laser array in the hetero-phased or phase-locked mode.
Detailed Description
The present detailed description relates to elements of the apparatus of the invention that make up the parts or that more directly cooperate with the apparatus. It is to be understood that elements not specifically shown or described may take various forms well known to those skilled in the art.
For the following description, a particular component in a monochromatic light path can be identified more specifically by appending a letter to the component number. Where used, the letters correspond to and are consistent with the color paths; for example, red is appended with "r", blue is appended with "b", and green is "g".
In the most general embodiment, the device of the present invention provides modulated light, one row at a time, with its light source being a VCSEL array and the light modulator being an electromechanical grating device. In the description that follows in this section, reference is primarily made to embodiments such as imaging in printing and display devices. It should be noted, however, that the apparatus of the present invention may also be used in other types of imaging devices, as well as other devices that utilize modulated laser light to perform various functions, such as signal sensing or recording functions.
In one embodiment, the apparatus of the present invention is part of an imaging device that images a surface, which may be a photosensitive medium or a projection screen, which may be front or rear projection. It is beneficial to recognize that there are significant differences between display and printing applications. The projection device is optimized to provide maximum illumination flux to the screen, and secondly to emphasize important features in the printing, such as photosensitivity and resolution. Optical systems in projectors and display applications are designed based on the response of the human eye, which is relatively insensitive to image artifacts and aberrations and image non-uniformities when viewing the display, since the displayed image is continuously refreshed and viewed from a distance. However, when viewing the printout of a high-resolution printing system, artifacts and aberrations, and image non-uniformities, are hardly "overshot" by the human eye, since irregularities in the optical response are more easily visible and objectionable in the printout. Even more noteworthy is the difference in resolution requirements. To accommodate the human eye, projection and display systems are typically optimized for viewing with a lower resolution than the printing device. For example, the resolution of the photographic printing apparatus should preferably be substantially higher than that required for display purposes to be able to produce images of essentially continuous tone quality. The source colors used have a significant effect on the color gamut for display purposes. However, for purposes of printing on photosensitive media, the wavelength used should preferably be consistent with the photosensitive characteristics of the media itself; the desired wavelength may or may not be in the visible range. The contrast ratio of bright and dark regions is a priority in a display environment, which requires a contrast ratio of 1000: 1 or higher. However, in some printing applications, the contrast ratio used for exposure is typically as low as 10: 1, which is acceptable because an acceptable photoreceptive response is obtained.
Referring to FIG. 6, there is shown an imaging device 10 for forming an image on a surface 90 in accordance with the present invention. The modulation assembly 120 includes the light source 20, the cylindrical lens 74 for modulating the light beam, a steerable turning mirror 82, and an electro-optic grating light modulator 85. The light source 20 provides an illumination beam 109 along the optical axis O that is modulated by the cylindrical lens 74 to form a suitable aspect ratio for impinging on the electromechanical grating light modulator 85. The light source 20 comprises a VCSEL array 100 operating in a phase-locked configuration as described above with reference to figure 1 b. The illumination beam 109 along axis O is incident into the electromechanical grating light modulator 85 through the turning mirror 82. The modulated light exiting the electromechanical grating light modulator 85 is diffracted through the turning mirror 82 and directed to the scanning mirror 77 through the lens 75. The turning mirror 82 acts as a blocking element for the zero order reflected light from the electromechanical grating modulator 85.
As the scan mirror 77 rotates, each modulation line image emerging from the electro-optic grating light modulator 85 forms a two-dimensional image on the surface 90. The logic control processor 80 provides image modulation data to the electromechanical grating light modulator 85 line by line, depending on the position of the scan mirror 77. Optionally, control of the light source 20 may also be provided by the control logic processor 80. To achieve high optical efficiency and high contrast, the projected lines of the image formed on surface 90 are preferably formed by two or more diffraction orders in the modulated light exiting electromechanical grating light modulator 85.
In one particular implementation, the electromechanical grating light modulator 85 is a GEMS device, but may also be a GLV device, with the components rearranged as necessary. For example, a GLV based system requires a turning mirror 82 to be placed in the fourier plane of the projection lens 75, as disclosed in the background description of U.S. patent No. 6411425. Surface 90 is a front projection screen in a particular implementation; however, similar structures and operations can also be applied to rear projection display screens or other viewing surfaces. Alternatively, surface 90 may be a photosensitive medium, such as photographic film or paper, for example. Other types of photographic media, electrophotographic media, or thermal media may also be used. Lens 75 acts as a projection or printing lens; in the position of the lens 75 in an actual imaging device 10, a lens assembly comprising a number of lens elements is used. An optional cross-order filter 160 is positioned near the fourier (focal) plane of lens 75 to minimize the projection of unwanted diffracted cross-orders in the modulated light.
Composition of light source 20
Referring to fig. 4, there is shown a schematic view of the construction of the light source 20 assembly of the present invention. The VCSEL array 100 includes a plurality of emitting elements 102 and 103 that provide a source beam 105 to a fourier transform lens 122. The Fourier transform lens 122 directs the source beam 105 into an illumination spatial filter 130 that conditions the source beam 105 to remove unwanted spatial content. The conditioned source beam 107 is then collimated by a lens 124 before forming the illumination beam 109. Focal length f shown in fig. 41And f2To showPreferably the spatial positional relationship between the components along the optical axis. Wherein if the focal length f1And f2Are equal, the structure according to figure 4 images a VCSEL array in a 1: 1 ratio. The magnification being dependent on the focal length f1And f2The ratio of (a) to (b).
Fig. 5a and 5b show possible configurations of the illumination spatial filter 130 according to the invention. As mentioned in the background section of the present application, the VCSEL array 100 can operate in a hetero-phased mode or configuration, as described with reference to the VCSEL emitting elements 102 and 103 in fig. 1a, and the beam spatial distribution in fig. 2a and 2 b. In the out-of-phase mode, the plano-convex of FIG. 5a shows the structure of an illumination spatial filter 130, which is purposely provided with holes 132 to allow the lobes 110a-110d to pass through. The shadow region of the illuminating spatial filter 130 blocks light having an unwanted spatial component. Similarly, fig. 5b shows the structure of the illumination spatial filter 130 in phase-locked mode, consistent with the arrangement of fig. 1b and the spatial distribution of the light beams in fig. 3a, 3 b. In fig. 5b, a single aperture 132 passes light from the central lobe 110 e.
Referring to fig. 7, one configuration of the light source 20 assembly is shown to provide illumination beams of each of the three colors of the present invention at once. The red VCSEL array 100r, the green VCSEL array 100g, and the blue VCSEL array 100b provide light to the color synthesizing element 73. The color combining element 73 then directs the light along a common output optical axis O into the fourier transform lens 122, illuminating the spatial filter 130, and finally the collimating lens 124 and providing the illumination beam. A specific example of the color synthesis element 73 is an X-cube (X-cube), but could also be a Philips prism or a suitable arrangement of dichroic surfaces as known in the optical design art.
Embodiments of color synchronized imaging
Referring to fig. 8, there is shown a configuration of an image forming apparatus 10 according to the present invention for use in color-synchronized imaging in a phase-locked mode, such as may be used in a full-color display apparatus, for example. A single light source 20r, 20g and 20b is provided, each corresponding to a red, green and blue modulating component 120r, 120g and 120b, respectively. The optical assembly of each light source 20r, 20g and 20b preferably has the basic structure shown in fig. 4. The red light source 20r is directed into the red electromechanical grating light modulator 85 r; the green light source 20g is directed into a green electromechanical grating light modulator 85 g; the blue light source 20b is directed into a blue electromechanical grating light modulator 85 b. One or more diffraction orders may be collected and directed for imaging as indicated in each modulation assembly 120r, 120g, or 120 b.
Fig. 9 shows an alternative multi-color, color-synchronized imaging arrangement according to the present invention, which can be used in either the out-of-phase mode described above with respect to fig. 1a, 2a and 2b, or in the phase-locked mode described above with respect to fig. 1b, 3a and 3 b. In the arrangement of FIG. 9, the electromechanical grating light modulators 85r, 85g, and 85b in each light modulation assembly 120r, 120g, and 120b are all positioned at oblique angles with respect to the corresponding light sources 20r, 20g, and 20 b. This placement eliminates the turning mirror 82 that directs illumination light to the electro-mechanical grating light modulators 85r, 85g, and 85b, respectively. Fig. 9 also shows the simplest possible arrangement of light source 20 components, with light sources 20r, 20g and 20b containing only VCSEL array 100; it is understood that, for example, in the green modulation component 120g, its green light source 20g includes only the green VCSEL array 100 g. The spatial filtering should preferably be done at some point in the optical path, either before or also after modulation. For spatial filtering of the light source illumination, each light source 20r, 20g and 20b may use an illumination spatial filter 130 as described with respect to fig. 4, 5a, 5b and 7. However, it is optimally set that a modulated light spatial filter 134 is disposed on each modulated light path as shown in fig. 9. In each modulation assembly 120r, 120g and 120b, the lens assembly 126 specifically forms an anamorphic magnified image of the corresponding VCSEL array 100 on the corresponding electromechanical grating light modulator 85r, 85g and 85b, respectively.
Fig. 10 shows a configuration of a modulated optical spatial filter 134, according to the present invention, with a source VCSEL array 100 within a light source 20 operating in a hetero-phased configuration as described with respect to fig. 1a, 2a and 2 b. It should be noted that the structure of the modulated optical spatial filter 134 is different depending on whether the out-of-phase mode or the phase-locked mode is used. The positions of the lobes 110a-110d in figure 2b correspond to the zero order reflected beams 210a, 210b, 210c and 210d shown in figure 10. Thus, in the arrangement of FIG. 9, the modulated light spatial filter 134 in each color path blocks the zeroth order reflected light beams 210a-210d from being incident on the color combining element 73 shown in FIG. 8. The modulated light, on the other hand, is diffracted from the electro-optic grating light modulator 85 and appears as pairs of modulated diffraction orders 210a +/210a-, 210b +/210b-, 210c +/210c-, and 210d +/210d-, as shown in FIG. 10. That is, the diffraction order pairs 210a + and 210 a-contain the first order diffracted light that is generated by the modulation lobe 110a of the electromechanical grating light modulator 85. Similarly, diffraction orders 210b + and 210 b-contain the first order diffracted light corresponding to lobe 110 b; diffraction orders 210c + and 210 c-contain the first order diffracted light corresponding to lobe 110 c; diffraction orders 210d + and 210 d-contain the first order diffracted light corresponding to lobe 110 d. Apertures 136 and 138 are sized and spaced to pass diffraction orders 210a +, 210a-, 210b +, 210b-, 210c +, 210c-, 210d +, and 210d-, as shown. It is noted that the modulated light spatial filter 134 shown in FIG. 10 uses only the first order diffracted light. The structure of the modulated optical spatial filter 134 can be further complicated if higher order diffracted light is used.
Reflective light mode (Reflected light mode)
The configuration of the apertures 136 and 138 used by the modulated light spatial filter 134 is adapted to pass the diffraction orders 210a +, 210a-, 210b +, 210b-, 210c +, 210c-, 210d +, and 210 d-. Conversely, however, a reflected light imaging mode is also an alternative, in which the apertures 136 and 138 are replaced by opaque diaphragms and the opaque portions of the modulated light spatial filter 134 are both replaced by transparent. (this corresponds generally to the use of an illumination spatial filter 130 that was originally designed to be placed in the illumination path instead of in the modulation path in the arrangement shown in FIG. 5 a) in such an alternative manner that only the zero order light emitted from the electro-optic grating light modulator 85 is directed to the surface 90. Non-zero diffraction orders are occluded. Imaging in this manner, light diffracted to ± 1 or higher orders is not included in the modulation light path; in the reflected light mode, only reflected, zero-order light is used. Due to contrast requirements, while reflected light imaging modes are not compatible with some types of imaging devices, for low contrast imaging applications, reflected light imaging modes may be used in imaging apparatus 10. Suitable imaging modes utilizing reflected light include, for example, some printing applications where high efficiency is required and only low to medium contrast is required. In the hetero-phase structure, the structure of the components shown in fig. 9 can be easily utilized as a reflected light imaging operation, and the modulated light spatial filter 134 has an opposite structure to that shown in fig. 10. If the reflected light imaging operation is under an alternative phase-locked configuration, the entire FIG. 9 configuration may be used, with the spatial filter 134 instead having only a single center hole.
Correcting aspect ratio of VCSEL emission
The electromechanical grating light modulator 85 has a high aspect ratio and requires that the incident illumination beam have a substantially equal aspect ratio. The VCSEL array 100 can be made with a high aspect ratio due to applications requiring incident illumination with a relatively low luminous flux in the application. In such applications, conventional spherical optics may be used to image the VCSEL array 100 onto the electro-optic grating light modulator 85 at a suitable magnification. However, as mentioned in the background section above, the VCSEL array 100 provides higher luminous flux when closer to a rectangular aspect ratio. To provide higher throughput illumination, anamorphic optics are used to perform aspect ratio conversion of the VCSEL array while the VCSEL array 100 is imaged on the electromechanical grating light modulator 85. For example, cylindrical lenses may be used for this purpose. The anamorphic magnification can be raised to the 10: 1 range using conventional techniques well known in the imaging arts.
In some applications, it is even desirable to achieve greater effective deformation magnification. Referring to FIG. 11, a light source 20 is shownAnother configuration can provide additional distortion magnification measurements. Light emitted from the VCSEL array 100 is directed by the fourier transform lens 122 into the microlens converter 140. The light input to the microlens converter 140 has the overall structure of the lobes 110a-110d shown in figure 12 a. The microlens converter 140 includes a cylindrical lens array 141a and a collimating lens array 141b, which cooperate to change the aspect ratio of the emitted light. The lens 142 directs light into the electromechanical grating light modulator 85. Focal length f of Fourier transform lens 122 and lens 1421And f2As illustrated. In this arrangement, the microlens converter 140 is disposed in the fourier plane of the fourier transform lens 122. As is well known in the optical arts, effective correction of the emission pattern (emision pattern) is possible at the fourier plane location.
Fig. 13a and 13b are partial perspective views illustrating respective structures of the cylindrical lens array 141a and the collimating lens array 141b in the microlens converter 140 of fig. 11 according to the present invention. Referring to fig. 13a, the cylindrical lens array 141a includes cylindrical microlens elements 144 arranged in a manner most suitable for adjusting the aspect ratio. The dashed lines indicate that cylindrical microlens elements 144 are disposed at the spatial locations of each lobe 110a-110 d. Referring to fig. 13b, the collimating lens array 141b includes an arrangement of collimating microlens elements 146 disposed at positions corresponding to the cylindrical microlens elements 144 used in the cylindrical lens array 141 a. The combination of cylindrical microlens elements 144 and collimating microlens elements 146, in correspondence with each lobe 110a-110d of the emitted light, adjusts the aspect ratio of the lobes 110a-110d as shown in figure 12a to achieve adjusted lobes 110a ', 110 b', 110c ', and 110 d' with more linear aspect ratios as shown in figure 12 b.
The invention has been described in detail with particular reference to certain specific embodiments thereof, but it will be understood that variations and modifications can be effected within the scope of the invention by a person of ordinary skill in the art without departing from the scope of the invention as described above and as claimed below. For example, the imaging device 10 may have some VCSEL arrays 100 operating in an out-of-phase configuration and other VCSEL arrays 100 operating in a phase-locked configuration. Furthermore, although the specific orientation has been described above with respect to the axis of symmetry of the VCSEL array 100 in the particular embodiment, different orientations may be used with respect to changes to the imaging device 10. Although an organic VCSEL array 100 is used in a specific embodiment, conventional inorganic VCSELs 100 may also be used. Imaging device 10 may form an image using conventional imaging, i.e., modulating diffracted light to illuminate surface 90, or reflected light imaging, i.e., reflected zeroth order light reflected from electro-optic grating light modulator 85. More than three VCSEL array 100 color light sources may be used to improve color gamut.
The scan mirror 77 acts as a scanning element in the particular embodiment. However, other suitable scanning elements may be used, including, for example, different types of prisms, rotating polygon mirrors, and electro-optical beam deflection devices. As an alternative arrangement for forming a scanned two-dimensional Display image, a planar Optical waveguide may be used, such as that described in U.S. Pat. No.5381502, filed by Veligdan on 1/10 1995, entitled "Flat or Curved Thin Optical Display Panel", in which the scanning mirror 77 may be arranged as a rotating polygon mirror. In printing devices, a media transport mechanism is used to scan and advance a medium at an appropriate rate over a modulated light path to form a two-dimensional image.
Figures 6, 8 and 9 show an arrangement of components in a specific embodiment according to the present invention, the electromechanical grating light modulator 85 of which is a GEMS device. Rearrangement of components is required if these arrangements are used with GLV apparatus using processes well known in the optical design arts and described in the background section of us patent No. 6411425. With respect to fig. 9, for example, a separate spatial filter 134 may be placed in the fourier plane of the projection lens 75 rather than placing a spatial filter 134 in each color modulation path. In fig. 6, a turning mirror 82 may be placed in the fourier plane of the projection lens 75, for example, using GLV modulation. Fig. 8 also requires a separate turning mirror 82 in the fourier plane of the projection lens 75 and will include a complex optical path, with the pre-combined light incident on the turning mirror 82, being split into component colors at the color combining component 73, then modulated, and then combined into its diffraction orders that are projected through the turning mirror 82 onto the scanning mirror 77.
Apparatus and methods for providing modulated light for imaging applications, such as in printers, projectors and display devices, have been described. It is important to note, however, that the apparatus of the present invention can be used in other types of imaging devices, as well as other devices that utilize modulated light energy to perform various functions, such as signal sensing or recording functions.
An image forming apparatus for forming an image on a surface includes: (a) a light source comprising at least a first VCSEL array having emitting elements to provide an illumination beam along an illumination axis; (b) a linear array of electromechanical grating devices for modulating the illumination beam in accordance with the image data and providing a modulated beam comprising a plurality of diffraction orders; (c) a blocking element for blocking at least one of the plurality of diffraction orders in the modulated light beam; (d) means for conditioning the illumination beam to provide a suitable aspect ratio for impinging on the linear array of electromechanical grating devices and/or to remove unwanted spatial content; and (e) a projection lens cooperating with the scanning element to project the modulated light onto the surface, thereby forming a line image on the surface.
Apparatus for forming an image on a surface, wherein a first VCSEL array is an organic VCSEL array.
Apparatus for forming an image on a surface in which a first VCSEL array is optically pumped.
Apparatus for forming an image on a surface, wherein light emitted by each emitting element of a first VCSEL array has the same phase.
Apparatus for forming an image on a surface in which light emitted from one emitting element of a VCSEL array and light emitted from its adjacent emitting element have opposite phases.
Apparatus for forming an image on a surface, wherein the linear array of electromechanical grating devices is a grating light valve.
Apparatus for forming an image on a surface, wherein the linear array of electromechanical grating devices is a conformal (conformal) GEMS device.
Apparatus for forming an image on a surface in which a shutter element also directs an illumination beam towards a linear array of electromechanical grating devices.
Apparatus for forming an image on a surface, wherein a blocking element blocks a zero order beam.
Apparatus for forming an image on a surface in which a blocking element blocks at least one primary beam.
Apparatus for forming an image on a surface, wherein a blocking element blocks at least one non-zero order beam.
Apparatus for forming an image on a surface, further comprising a lens for imaging a first VCSEL array onto a linear array of electromechanical grating devices.
Apparatus for forming an image on a surface wherein a projection lens adjusts the aspect ratio of a first VCSEL array.
Apparatus for forming an image on a surface, wherein the scanning element is selected from the group consisting of a turning mirror, a polygon mirror, a prism, an electro-optic beam deflecting element, and a media transport device.
An imaging device for forming an image on a surface, wherein the surface is a front projection screen (front projection).
An imaging device for forming an image on a surface, wherein the surface is a rear projection screen (rear projection).
An imaging device for forming an image on a surface, wherein the surface comprises a planar optical waveguide.
An image forming apparatus forms an image on a surface, wherein the surface is a photosensitive medium.
An image forming apparatus for forming an image on a surface, wherein the photosensitive medium is selected from the group consisting of photographic media, electrophotographic media, and thermal media.
An image forming apparatus for forming an image on a surface, further comprising: (e) a logic control processor provides image data to the linear array of electromechanical grating devices based on the position of the scanning element.
An imaging device for forming an image on a surface, wherein the means for conditioning the illumination beam comprises an illumination spatial filter.
An imaging device for forming an image on a surface, wherein the light source further comprises a Fourier transform lens for directing light from the first VCSEL array to the illumination spatial filter.
Imaging apparatus for forming an image on a surface, wherein a first VCSEL array emits a source beam having at least one lobe, and wherein the light source further comprises: (i) a fourier transform lens that projects the source beam towards a converter element disposed adjacent a fourier plane of the fourier transform lens, the converter element modifying an aspect ratio of at least one lobe to provide a modified source beam; and (ii) a lens that supplies the modified source beam as the illumination beam.
An imaging apparatus for forming an image on a surface, wherein a first VCSEL array emits a first source beam having a first color, and the light source further comprises: (a) a second VCSEL array emitting a second source beam having a second color; (b) a third VCSEL array emitting a third source beam having a third color; (c) a color combining element for directing the first, second and third source beams onto the illumination axis.
An imaging device for forming an image on a surface, wherein the light source further comprises a Fourier transform lens for directing light on an illumination axis to the illumination spatial filter.
An imaging device for forming an image on a surface, wherein the transducer element comprises a microlens array.
An image forming apparatus for forming an image on a surface, comprising: (a) first, second and third color modulation assemblies, each providing an imaging beam having first, second and third colors, respectively, each modulation assembly comprising: (i) a VCSEL array that generates illumination beams from a plurality of emitting elements in the VCSEL array; (ii) a linear array of electromechanical grating devices for modulating the illumination beam in accordance with the image data and providing a modulated beam comprising a plurality of diffraction orders; (iii) a blocking element for blocking at least one of the plurality of diffraction orders in the modulated beam and providing an imaging beam; (iv) adjusting the illumination beam means to provide a suitable aspect ratio for impinging on the array of electromechanical grating means and/or to remove unwanted spatial content; (b) a color combining element for combining the first, second, and third color imaging beams along a single output axis to form a multi-colored modulated beam; (c) a lens element cooperates with the scanning element and projects the polychromatic modulated light towards the surface, thereby forming a polychromatic line image on the surface.
Apparatus for forming an image on a surface, wherein the VCSEL array is an organic VCSEL array.
Apparatus for forming an image on a surface in which a VCSEL array is optically pumped.
Apparatus for forming an image on a surface, wherein light emitted by each of a plurality of emissive elements in a VCSEL array has the same phase.
Apparatus for forming an image on a surface in which light emitted from one emitting element of a VCSEL array and light emitted from its adjacent emitting element have opposite phases.
Apparatus for forming an image on a surface, wherein the linear array of electromechanical grating devices is a conformal (conformal) GEMS device.
A shutter element in the apparatus also directs the illumination beam to the linear array of electromechanical grating devices.
Apparatus for forming an image on a surface in which a zero order beam is blocked by a blocking element.
Apparatus for forming an image on a surface, wherein a blocking element blocks at least one non-zero order beam.
Apparatus for forming an image on a surface, wherein a blocking element blocks at least one primary beam.
Apparatus for forming an image on a surface, the means for conditioning the illumination beam comprising a lens for imaging the VCSEL array onto the linear array of electromechanical grating devices.
Apparatus for forming an image on a surface in which a lens adjusts the aspect ratio of a VCSEL array.
Apparatus for forming an image on a surface, wherein the scanning element is selected from the group consisting of a turning mirror, a polygon mirror, a prism, an electro-optic beam deflecting element, and a media transport device.
An imaging device for forming an image on a surface, wherein the surface is a front projection screen (front projection).
An imaging device for forming an image on a surface, wherein the surface is a rear projection screen (rear projection).
An imaging device for forming an image on a surface, wherein the surface comprises a planar optical waveguide.
An image forming apparatus forms an image on a surface, wherein the surface is a photosensitive medium.
An image forming apparatus for forming an image on a surface, wherein the photosensitive medium is selected from the group consisting of photographic media, electrophotographic media, and thermal media.
An image forming apparatus for forming an image on a surface, further comprising: (e) a logic control processor provides image data to each of the linear arrays of electromechanical grating devices based on the position of the scanning element.
An imaging device for forming an image on a surface, wherein a color modulation assembly includes an illumination spatial filter to condition an illumination beam.
An imaging device for forming an image on a surface, wherein the color modulation assembly further comprises a Fourier transform lens for directing light from the VCSEL array to the illumination spatial filter.
A color modulation assembly in an imaging device emits a source beam having at least one lobe, the color modulation assembly further comprising: (i) a fourier transform lens that projects the source beam towards a converter element disposed adjacent a fourier plane of the fourier transform lens, the converter element modifying an aspect ratio of at least one lobe to provide a modified source beam; and (ii) a lens that supplies the modified source beam as the illumination beam.
The color synthesis element in the imaging device may be selected from a group of elements including an X-cube (X-cube) and a Philips prism.
An image forming apparatus for forming an image on a surface, wherein the color synthesis element includes an arrangement of dichroic surfaces.
An imaging device for forming an image on a surface, wherein the transducer element comprises a microlens array.
A method of providing a modulated light beam comprising: (a) generating an illumination beam from a VCSEL array having a plurality of emitting elements therein; (b) modulating an illumination beam at an electromechanical grating device in a linear array to provide a plurality of diffraction orders; (c) blocking at least one of the plurality of diffraction orders to form a modulated light beam; (d) the illumination beam is conditioned to provide a suitable aspect ratio for impinging on the array of electromechanical grating devices, and/or to remove unwanted spatial content.
A method of modulating a light beam is provided, wherein the VCSEL array is an organic VCSEL array.
A method of modulating a light beam is provided, wherein the step of generating an illumination beam comprises the step of optically pumping a VCSEL array.
A method of modulating a light beam is provided, wherein the step of generating an illumination beam from a VCSEL array comprises exciting adjacent emitting elements in the VCSEL array to emit with the same phase.
A method of modulating a light beam is provided wherein the step of generating an illumination beam from a VCSEL array comprises exciting adjacent emitting elements in the VCSEL array to emit in opposite phases.
A method of modulating a light beam is provided wherein the linear array of electromechanical grating devices is a grating light valve.
A method of modulating an optical beam is provided wherein a linear array of electromechanical grating devices is a conformal (conformal) GEMS device.
A method of modulating an optical beam is provided, wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking zero order diffraction.
A method of modulating an optical beam is provided, wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking at least one non-zero diffraction order.
A method of modulating an optical beam is provided, wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking a first diffraction order.
A method of modulating a light beam is provided wherein the step of conditioning the illumination beam further comprises the step of providing an illumination spatial filter to shape light emitted from the VCSEL array into a set of lobes as the illumination beam.
A method of modulating a light beam is provided wherein the step of generating an illumination beam comprises the step of imaging a VCSEL array onto a linear array of electromechanical grating devices.
A method of modulating a light beam is provided wherein the step of imaging the VCSEL array further comprises the step of anamorphic amplifying the VCSEL array.
A method of forming an image on a surface comprising the steps of: (a) providing an illumination beam from a VCSEL array having a plurality of emitting elements within the array, wherein the VCSEL array is excited by a source beam; (b) adjusting the source beam to remove unwanted spatial content; (c) modulating the illumination beam in a linear array of electromechanical grating devices in accordance with the image data to provide a plurality of diffraction orders; (d) blocking at least one of the plurality of diffraction orders to form an imaging beam; (e) projecting an imaging beam toward a surface.
A method of forming an image, wherein the step of conditioning the source beam further comprises the step of filtering the source beam to remove unwanted spatial content.
A method of forming an image wherein the step of projecting an imaging beam further comprises the step of directing the imaging beam to a scanning element.
A method of forming an image wherein the VCSEL array is an organic VCSEL array.
A method of forming an image wherein the step of providing an illumination beam further comprises the step of optically pumping the VCSEL array.
A method of forming an image wherein the step of providing an illumination beam from a VCSEL array comprises exciting adjacent emitting elements on the VCSEL array to emit at the same phase.
A method of forming an image wherein the step of providing an illumination beam from a VCSEL array comprises exciting adjacent emitting elements on the VCSEL array to emit in opposite phases.
A method of forming an image wherein a linear array of electromechanical grating devices is a grating light valve.
A method of forming an image wherein a linear array of electromechanical grating devices is a conformal (conformal) GEMS device.
A method of forming an image, wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking zero order diffraction.
A method of forming an image, wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking at least one non-zero diffraction order.
A method of forming an image wherein the step of blocking at least one of the plurality of diffraction orders comprises the step of blocking a first diffraction order.
A method of forming an image, wherein the step of filtering the source beam comprises the step of providing an illumination spatial filter to form a set of lobes emitted in the VCSEL array as an illumination beam.
The method of forming an image further comprises the step of positioning a fourier transform lens to direct light from the VCSEL array to the illuminated spatial filter.
A method of forming an image wherein the step of providing an illumination beam comprises the step of imaging a VCSEL array onto a linear array of electromechanical grating devices.
A method of forming an image wherein the step of imaging the VCSEL array further comprises the step of anamorphic magnification of the VCSEL array.
A method of forming an image, wherein the surface may be selected from a group of surfaces including a front projection screen, a rear projection screen, and a planar optical waveguide.
A method of forming an image wherein the surface is a photosensitive medium.
The method of forming an image further includes the step of transporting a photosensitive medium in the imaging beam path.
A method of forming an image wherein the step of providing an illumination beam from a VCSEL array comprises the step of passing the emitted light through a color combining element.
To this end, an apparatus is provided for modulating a light beam emitted from a VCSEL laser source and scanning one or more diffraction orders of the light beam onto a surface via an electromechanical grating device.