US20060061846A1 - Scanned light display system using array of collimating elements in conjunction with large numerical aperture light emitter array - Google Patents

Abstract

A scanned light display system includes a light emitter array having a plurality of light sources operable to emit diverging light and an array of collimating elements positioned so that each of the collimating elements receive at least a portion of the light emitted from a corresponding one of the light sources. Each of collimating elements is configured to substantially collimate the received light from at least one corresponding light source into respective beams. The scanned beam display is operable to scan the respective beams to provide an image to a viewer. The displayed image appears substantially fixed to a viewer as the viewer's eye moves relative to the array of collimating elements. In one embodiment, each of the collimating elements is a curved mirror. In other embodiments, each of the collimating elements includes at least one lens or a curved mirror/lens pair.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of Provisional Application No. 60/610,911, filed Sep. 17, 2004, the disclosure of which is incorporated herein by reference.
• This application relates to U.S. patent application Ser. No. 11/078,970, entitled SCANNED LIGHT DISPLAY SYSTEM USING LARGE NUMERICAL APERTURE LIGHT SOURCE, METHOD OF USING SAME, AND METHOD MAKING SCANNING MIRROR ASSEMBLIES, filed on Mar. 9, 2005, the disclosure of which is incorporated herein by reference.
TECHNICAL FIELD
• This invention relates to scanned light display systems, and more particularly to scanned light displays having a light emitter array used in conjunction with an array of collimating elements.
BACKGROUND
• A variety of techniques are available for providing visual displays of still or video images to a user. One form of display is a scanned beam display. In one example of a scanned beam display, a scanning light source outputs a beam of coherent light that is reflected by a mirror in a MEMS scanner onto a viewer's retina. The scanned light enters the viewer's eye through the viewer's pupil and is directed onto the retina by the cornea and lens. The intensity of the light from the light source is modulated as the beam is scanned horizontally and vertically so that the viewer perceives an image. In other examples, the scanning source may include one or more modulated light emitters that are rotated through an angular sweep to scan the light onto the viewer's retina.
• A typical requirement of scanned beam displays has been the need to collimate the light into a beam having a relatively small numerical aperture, i.e., a small divergence angle, prior to scanning the beam across the field-of-view. Unfortunately, providing a collimated, low numerical aperture beam of light frequently employs relatively expensive coherent light sources such as lasers, or edge-emitting light emitting diodes (“EELED”). Such collimated light sources may result in low optical efficiency and have the effect of producing a dimly lit display. Additionally, conventional scanned beam displays may require a relatively complex set of optics to deliver a scanned beam image.
SUMMARY
• Apparatuses and methods for scanned light display systems are disclosed. According to one aspect, a scanned light display system includes a light emitter array having a plurality of light sources operable to emit diverging light and an array of collimating elements. Each of the collimating elements corresponds to one or more of the light sources and is positioned to receive at least a portion of the diverging light from the corresponding one or more of the light sources. Each of the collimating elements is configured to substantially collimate the received diverging light into respective beams. The scanned light display system further includes an actuator system coupled to at least one of the light emitter array and the array of collimating elements, the actuator system being operable to move at least one of the light emitter array and the collimating elements to scan the respective beams to provide an image to a viewer.
• The scanned beam display systems described herein enable the image displayed to the viewer to appear substantially fixed as the viewer's eye moves relative to the array of collimating elements.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1A is a schematic cross-sectional view of a scanned beam display having a mirror array with each curved mirror of the mirror array having at least one corresponding light emitter according to one embodiment.
• FIG. 1B is a schematic cross-sectional view of a scanned beam display having a mirror array with each curved mirror of the mirror array having at least one corresponding light emitter according to an embodiment having a different scale than the embodiment ofFIG. 1A.
• FIG. 2 is a schematic plan view of the mirror array and light emitter array ofFIG. 1A and 1B.
• FIG. 3 is a schematic cross-sectional view of the mirror array and the light emitter array of FIGS.1A-B and2 with the curved mirrors of the mirror array operable to be rotated to scan the light received from the light emitters.
• FIG. 4 is a schematic cross-sectional view of the mirror array and the light emitter array ofFIG. 1A-B and2 with the curved mirrors of the mirror array operable to be moved vertically to scan the light received from the light emitters.
• FIG. 5 is a schematic cross-sectional view of a scanned beam display having a lens array with each lens of the lens array having at least one corresponding light emitter according to one embodiment.
• FIG. 6 is a schematic cross-sectional view of a scanned beam display having a mirror array and a lens array with a light emitter array positioned therebetween according to one embodiment.
• FIG. 7 is a block diagram of a control system according to one embodiment that may be used to physically scan the light emitters of the light emitter array.
• FIG. 8 is a schematic exploded isometric view of a scanned beam display in which the display is mounted in a pair of eyeglass according to an embodiment.
• FIG. 9 is a diagram showing three sets of respective beams, each corresponding to a different one of a triad of light emitters.
• FIG. 10 is a diagram showing parallelism of beams output from corresponding emitters in a triad of light emitters.
• FIG. 11 is a diagram showing parallelism of beams output from different corresponding emitters in a triad of light emitters.
• FIG. 12 is a diagram showing parallelism of beams output from a third set of corresponding emitters in a triad of light emitters.
• FIG. 13 is a diagram showing a mirror position at an instant in time when a first emitter in a triad of emitters is outputting light corresponding to a first pixel.
• FIG. 14 is a diagram showing a mirror position at a second instant in time when a second emitter in a triad of emitters is outputting light corresponding to the first pixel.
• FIG. 15 is a diagram showing a mirror position at a third instant in time when a third emitter in a triad of emitters is outputting light corresponding to the first pixel.
• FIG. 16 is a block diagram of a scanned light display system used in conjunction with, or as a subsystem of a still or video camera or other stored image viewing system according to an embodiment.
• FIG. 17 is a block diagram of a media viewer capable of rendering still and/or video images to a user from a streaming and/or wireless media source according to an embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
• Apparatuses and methods directed to scanned beam displays that employ an array of collimating elements to substantially collimate light emitted by a light emitter array are disclosed. As will be apparent from the description of the various embodiments below, the collimating elements may be curved mirrors, lenses, or lens/curved mirror pairs.FIGS. 1A, 1B, and2 show a scannedbeam display100 according to one embodiment. The display100 includes amirror array106 positioned in front of apupil112 of a viewer'seye115. Whereas the system ofFIG. 1A illustrates a personal display system aligned with a single viewer'seye115,FIG. 1B illustrates a larger scale display system that may be simultaneously viewed by several viewers. In each case, themirror array106 includes a plurality ofcurved mirrors108 with each of thecurved mirrors108 configured, for example, as a spherical mirror. Thedisplay100 further includes alight emitter array103 having a plurality oflight emitters102. In the embodiments shown inFIGS. 1A, 1B, and2, eachlight emitter102 is positioned in front of a correspondingcurved mirror108, and located on or proximate the focal surface of a correspondingcurved mirror108. Each of thelight emitters102 is operable to emit diverging light104 (i.e., light having a relatively large numerical aperture). In some contexts, thelight emitters102 may also be referred to as Lambertian light sources, though not all large numerical aperture devices are Lambertian.
• Theindividual light emitters102 of thearray103 may be a light source, such as a surface-emitting LED light source, an organic LED (OLED) light source, an edge emitting light emitting diode, a laser diode, a diode-pumped solid state (dpss) laser, a photoluminescent spot, a reflector, a fiber-optic source, or another suitable light source. In some embodiments, each of thelight emitters102 may include a plurality of light emitters such as, for example, an RGB triad or an RGBG quadrad. The relative intensity of the RGB or RGBG emitters may be controlled to replicate the color of a correspondingly positioned location in the image being displayed. If thelight emitter102 emits light in all directions, the eye side of thelight emitters102 should be masked so that any light104 emitted therefrom is only directed toward a correspondingcurved mirror108 and masked from being directed onto the viewer'seye115.
• The aforementioned light sources emit light in a cone or Lambertian pattern that fills a correspondingcurved mirror108 substantially uniformly. Uniformly filling thecurved mirrors108 improves image uniformity because different portions of the beam reflected by thecurved mirrors108 may enter thepupil112 from different angles during a horizontal and vertical sweep ofrespective beams118. Although the efficiency of thelight emitters102 may be less than optimum because a portion of the light104 may miss a correspondingcurved mirror108, the numerical aperture of the individuallight emitters102 may be substantially matched to the collection numerical aperture of a correspondingcurved mirror108 to provide greater efficiency, while meeting other design constraints.
• FIG. 2 shows a plan view of themirror array106 and thelight emitter array103. InFIG. 2, only some of the individuallight emitters102 are provided with reference numerals for clarity. Themirror array106 and thelight emitter array103 is depicted inFIG. 2 as a two-dimensional rectangular array with each of thecurved mirrors108_mnconfigured so that the peripheral edges thereof abut an adjacent one of the curved mirrors108_mn. However, depending upon the quality of the image desired, thecurved mirrors108 may be slightly spaced apart so that they do not abut each other. The configuration for themirror array106 and thelight emitter array103, and the precise number ofcurved mirrors108 andlight emitters102 may vary depending upon the particular application. In one embodiment, themirror array106 and thelight emitter array103 has a hexagonal configuration or another suitable configuration. In an alternative embodiment, themirror array106 is a one-dimensional mirror array. Thedisplay100 may be configured as a see-through display in which a background image positioned behind themirror array106 is visible, for example if thecurved mirrors108 of themirror array106 are semi-transparent, or if beams from themirror array106 are reflected to the user though a semi-transparent reflective surface.
• Thecurved mirrors108 of themirror array106 may have a relatively small radius of curvature. Thus, the focal surface of each of thecurved mirrors108 is located a shorter distance from a respectivecurved mirror108, and each of thelight emitters104 are positioned relatively closer to a correspondingcurved mirror108, than if a corresponding single large curved mirror was employed. This may be used, for example, to form a relatively thin and lightweight mirror array106/light emitter array103 structure. Employing a relatively thin and lightweight mirror array106/light emitter array103 structure facilitates using such a structure in place of a conventional lens in a pair of eyeglasses or another suitable head worn apparatus.
• Thecurved mirrors108 of themirror array106 provide two functions. First, thecurved mirrors108 substantially collimates the light104 emitted from correspondinglight emitters102 intorespective beams118. Each of thebeams118 are generally parallel to each other, and collectively define acomposite beam119. Depending upon the size and pitch of thecurved mirrors108, thebeams118 may be larger or smaller than the diameter of the viewer'spupil112. Themirror array106 may be configured so that the lateral spacing betweenadjacent beams118 is smaller than the diameter of the viewer'spupil112. In some embodiments, each of thebeams118 abuts anadjacent beam118 so that the lateral spacing betweenadjacent beams118 is insubstantial or nonexistent. When the diameter of the viewer'spupil112 is smaller than the diameter of abeam118, relativelyfewer beams118 enter the viewer'seye115 at any one time compared to the case where diameter of the viewer'spupil112 is larger than the diameter of thebeam118, and only a portion of thebeam118 enters the viewer'spupil112.
• Thecomposite beam119 is scanned across a viewer'spupil112, using scanning techniques that will be discussed in more detail below inFIGS. 3 and 4, with thebeams118 that enter the viewer'spupil112 being focused by the viewer'slens114 onto theretina116. The degree of collimation provided by a respectivecurved mirror108 generally corresponds to an apparent image distance. Generally, the plurality ofcurved mirrors108 provides the full field-of-view to the viewer. One of thecurved mirrors108 contributes a first portion of the field-of-view and at least a secondcurved mirror108 contributes a second portion of the field-of-view. Depending upon the position and movement of the viewer'spupil112 relative to thelight emitter array103, differentcurved mirrors108 may provide a particular pixel during a particular video frame.
• In operation, thecomposite beam119 is scanned across the viewer'spupil112 to display an image to the viewer. Each pixel of the displayed image is associated with a particular angle of incidence of thebeam118 relative to the viewer'spupil112. Each of the pixels is formed by scanning thecomposite beam119 so that at least one of thebeams118 having the angle of incidence with the viewer'spupil112 associated with a particular pixel is received by the viewer'spupil112. Thus, thebeam118 of one of thecurved mirrors108 may provide a particular pixel and thebeam118 of at least another one of thecurved mirrors108 may provide another pixel. The particular pixel provided by thebeam118 of a respectivecurved mirror108 depends upon whether thebeam118 is received by the viewer'spupil112. For example, as shown inFIG. 1, each of thebeams118 of thecomposite beam119 will generate the same pixel when received by the viewer'spupil112 because the angle of incidence between each of thebeams118 and the viewer'spupil112 is the same for each of thebeams118. Thus, if themirror array106 is displaced vertically relative to the viewer'spupil112 due to vibration or the viewer'seye115 moving, at least one of thebeams118 will be received by the viewer'spupil112 to form the pixel. In other words, it does not matter whichparticular beam118 the viewer'spupil112 receives so long as one of thebeams118 having the angle of incidence with the viewer'spupil112 is received thereby. Accordingly, the displayed image appears substantially fixed to the viewer regardless of any relative movement between themirror array106 and the viewer'seye115. Furthermore, there may be cases where a portion of a displayed image will not be perceived by the viewer because the relative orientation of themirror array106 and the viewer'spupil112 will not enable therequisite beams118 that form the missing portion to be received by the viewer'spupil112.
• Different portions of themirror array106 provides different portions of the displayed image. Again referring toFIG. 2, for example, if the viewer'spupil112 is centered approximately on thecurved mirror108₄₅, the pixels for the lower portion of the displayed image are provided by thecurved mirrors108 located below the line B-B and the pixels for the upper portion of the displayed image perceived by the viewer is provided by thecurved mirrors108 located above the line B-B. Similarly, the pixels for the left portion of the displayed image perceived by the viewer is provided by thecurved mirrors108 located to the left of the line A-A and the pixels for the right portion of the displayed image are provided by thecurved mirrors108 located to the right of the line A-A. If themirror array106 is displaced or the viewer'seye115 moves relative to themirror array106, then each of thecurved mirrors108 contributes a different portion of the displayed image than the previous example where the viewer's pupil was centered on the curved mirror10845. For example, if themirror array106 is displaced upwardly so that the viewer's pupil212 is centered on thecurved mirror108₇₅, there are no longer anycurved mirrors108 located at a position corresponding to the bottom portion of the displayed image. Therefore, the bottom portion of the displayed image will no longer be visible to the viewer and the upper portion of the displayed image will be provided by mirrors approximately below line B-B. Regardless of which particularcurved mirrors108 the pixels are provided from, the displayed image appears substantially fixed to the viewer with any relative displacement between themirror array106 and the viewer'seye115.
• Stated another way, thebeams118 from each of thecurved mirrors108 may be scanned to generate corresponding identical images. However, the viewer'spupil112 does not receive the entire image from each of the curved mirrors108. Instead, only a portion of the images from some or all of the respectivecurved mirrors108 are received by the viewer'spupil112. Furthermore, although each of thecurved mirror108/light emitter102 pairs generate identical images, some of thecurved mirror108/light emitter102 pairs may not contribute to the displayed image perceived by the viewer if the location of a particularcurved mirror108/light emitter102 pair relative to the viewer'spupil112 is outside the range that the particular curved mirror/light emitter102 pair can scan thebeams118 to be received by the viewer'spupil112.
• Various techniques for scanning thecomposite beam119 may be used. In one embodiment shown inFIG. 3, thecomposite beam119 is scanned by individually scanning each of thebeams118 reflected from corresponding curved mirrors108. Thebeams118 reflected from correspondingcurved mirrors108 are scanned in the vertical z-axis direction by tilting, i.e., rotating each of thecurved mirrors108 about the x-axis using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of the curved mirrors108. In an alternative embodiment, thebeams118 reflected from correspondingcurved mirrors108 may be scanned in the vertical z-axis direction by vertically moving each of thecurved mirrors108 in the z-axis direction without rotation thereof using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of the curved mirrors108. Rotating and/or vertically moving respectivecurved mirrors108 will scan correspondingbeams118 in the vertical z-axis across direction the viewer'spupil112.
• FIG. 4 shows an alternative embodiment for scanning thecomposite beam119 by individually scanning each of thebeams118. Thebeams118 are scanned by vertically moving each of thelight emitters102 in the z-axis direction, while a correspondingcurved mirror108 is maintained substantially stationary. In one embodiment, each of thelight emitters102 move in a curved path in order to remain on or proximate the focal surface of a correspondingcurved mirror108 using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of thelight emitters102. In yet another alternative embodiment, themirror array106/light emitter array103 structure is tilted, i.e., rotated about the x-axis as a unit to scan thebeams118 in the vertical z-axis direction using a single actuator (not shown) that is coupled to all of thelight emitters102 andcurved mirrors108. In yet another alternative embodiment, combinations of any of the aforementioned embodiments for scanning thebeams118 are used. Similarly, according to various embodiments, thebeams118 may be scanned in the horizontal x-axis direction by tilting, i.e., rotating each of thecurved mirrors108 about the z-axis, horizontally moving each of thecurved mirrors108 in the x-axis direction without rotation thereof, horizontally moving each of thelight emitters102 in the x-axis direction along a path that may maintain thelight emitters102 on or proximate the focal surface of a correspondingcurved mirror108 while thecurved mirrors108 are maintained substantially stationary, tilting themirror array106 and thelight emitter array103 as a unit about the z-axis direction, or combinations thereof. Accordingly, the image generated by each of thecurved mirror108/light emitter102 pairs and, consequently, the displayed image to the viewer, may be formed by the combination of horizontal and vertical scanning in conjunction with modulation of thelight emitters102.
• The individualcurved mirrors108 andlight emitters102 may be scanned at various rates. According to various embodiments, thecurved mirrors108 andlight emitters102 are individually scanned or scanned as a unit, if applicable, at a frame rate of, 60 Hz for example, and eachlight emitter102 in thearray103 is modulated at a frequency of 36 KHz to provide a display having the quality of an SVGA display. In one embodiment, thebeams118 of thecurved mirror108/light emitter102 pairs are scanned synchronously. In an alternative embodiment, thebeams118 of thecurved mirror108/light emitter102 pairs are scanned asynchronously. During asynchronous scanning of thebeams118, thelight emitters102 of each of thecurved mirror108/light emitter102 pairs emits light104 at the same intensity for a given angle of incidence between thebeam118 and the viewer'spupil112, although not at the same time. In either embodiment, if thecurved mirrors108 are rotated or translated horizontally and/or vertically, thecurved mirrors108 are moved in a manner to prevent physical interference between adjacentcurved mirrors108.
• In some embodiments, it may be desirable that the some of thecurved mirrors108 only provide selected pixels of the image displayed to the viewer in order to reduce power consumption. For example, with reference toFIG. 2, thelight emitters102 of the upper row of curved mirrors108₁₁-108₁₉may not be activated to provide pixels for the lower portion of the image displayed to the viewer.
• FIG. 5 shows a scannedbeam display120 that employs a lens array instead of a mirror array to collimate the light emitted from the light emitter array according to an embodiment that is structurally similar to thedisplay100 ofFIG. 1. Therefore, in the interest of brevity, components in bothdisplays100,120 that are identical to each other have been provided with the same reference numerals, and an explanation of their structure and function will not be repeated unless the components function differently in the twodisplays100,120. Thedisplay120 includes alens array122 positioned in front of the viewer'seye112. Thelens array122 includes a plurality oflenses124. Thedisplay120 further includes alight emitter array103 having a plurality oflight emitters102. Each of thelenses124 has acorresponding light emitter102. In one embodiment, each of thelenses124 may be a doublet. In other embodiments, each of thelenses124 may be a converging lens or another suitable type of lens that is configured to substantially collimate light emitted from thelight emitters102. Thelens array122 and thelight emitter array103 may have any of the aforementioned geometric configurations as themirror array106 and thelight emitter array103 of thedisplay100 shown inFIG. 1, such as a 1-D, 2-D, hexagonal, rectangular array oflenses122 andlight emitters102, etc.
• In operation, each of thelight emitters102 emits diverging light104 having a relatively large numerical aperture. Each of thelenses124 receives corresponding light104, and collimates the light104 intorespective beams126 to form acomposite beam127 defined by each of thebeams126 that are generally parallel to each other. As with thedisplay100, each of thebeams126 may abut each other or may be laterally spaced apart a distance smaller than the diameter of the viewer'spupil112. Similar to thedisplay100 ofFIG. 1, each of thelenses124/light emitter102 pairs is operable to scan thecomposite beam127 across the viewer'spupil112. The scanning of thecomposite beam127 is performed in a manner identical to thedisplay100 ofFIG. 1 except instead of thecurved mirrors108 being translated or rotated, thelenses124 may be translated or rotated. In the interest of brevity such scanning techniques will not be discussed thoroughly.
• One suitable actuator system for moving therespective lenses124 of thelens array122 relative to the correspondinglight emitters102 is disclosed in U.S. Pat. No. 6,104,832 to Melville et al., the disclosure of which is incorporated herein by reference. The actuator systems disclosed in the '832 Patent may also be adapted to move thecurved mirrors108, thelight emitters102 of the display100 (FIG. 1) and the display128 (FIG. 6), and/or the light source/mirror or light source/lens assembly. Various actuator systems such as electrostatic, electrocapacitive, electromagnetic, bimetallic, galvanometric, piezoelectric, combinations thereof, and others may be used to scan some or all of the components described herein.
• FIG. 6 shows a scannedbeam display128 that is structurally similar to the scannedbeam displays100 and120 ofFIGS. 1 and 5. Therefore, in the interest of brevity, components in bothdisplays100,120,128 that are identical to each other have been provided with the same reference numerals, and an explanation of their structure and function will not be repeated unless the components function differently in the twodisplays100,120,128. Thedisplay128 includes amirror array106 positioned in front of the viewer'spupil112. Alens array122 having a plurality oflenses124 is located between thelight emitter array103 and the viewer'spupil112. Each of thelight emitters102 is located forward or aft of the focal surface of a correspondingcurved mirror108.
• In operation, each of thelight emitters102 emit diverging light104 that is reflected from a correspondingcurved mirror108. However, since thelight emitters102 are located forward or aft of the focal surface of a correspondingcurved mirror108, the light reflected from a correspondingcurved mirror108 will not be collimated (e.g., slightly divergent). Each of thelenses124 substantially collimates the light reflected from a correspondingcurved mirror108 intorespective beams128 that define acomposite beam130. As with thedisplay100 ofFIG. 1 and thedisplay120 ofFIG. 2, thecomposite beam130 is scanned across the viewer'spupil112 to form the displayed image.
• Various techniques for scanning thecomposite beam130 across the viewer'spupil112 may be used. In one embodiment, thecomposite beam130 is scanned by individually scanning each of thebeams128. In one embodiment, each of thelight emitters102 are moved vertically in the z-axis direction, while thelens array122 and themirror array106 are maintained substantially stationary in order to vertically scan light in the z-axis direction collimated by each of thelenses124 using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of thelight emitters102. In an alternative embodiment, each of thelight emitters102 may be rotated about an axis that extends through or proximate acorresponding lens124 in the x-axis direction. In this embodiment, each of thelight emitters102 rotates so that it is located on or proximate the focal surface of the optical system defined by acurved mirror108/lens124 pair. In an alternative embodiment, each of thecurved mirrors108 and correspondinglight emitters102 are maintained substantially stationary and each of thelenses124 may be tilted, i.e., rotated about the x-axis, moved vertically in the z-axis direction, or combinations thereof to scan the beam across the viewer'spupil112 in the vertical z-axis direction using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of thelenses124. In yet another alternative embodiment, each of thelenses124 and correspondinglight emitters102 are maintained substantially stationary, while the light collimated by thelenses124 may be scanned in the vertical z-axis direction in a manner similar to thedisplay100 ofFIG. 1 by tilting, i.e., rotating each of thecurved mirrors108 about the x-axis, vertically moving each of thecurved mirrors108 in the z-axis direction without rotating thecurved mirrors108, or combinations thereof using an actuator that may be one of a set of horizontal and vertical actuators (not shown) coupled respectively to each of the curved mirrors108. In one embodiment that does not individually scan each of thebeams128, themirror array106/lens array122/light emitter array103 structure is tilted as a unit about the x-axis direction.
• According to various embodiments, thebeams128 may be scanned in the horizontal x-axis direction by tilting, i.e., rotating each of thelenses124 about the z-axis, horizontally moving each of thelenses124 in the x-axis direction without moving a correspondingcurved mirror108/light emitter102, horizontally moving each of thelight emitters102 in the x-axis while a correspondingcurved mirror108/lens124 is maintained substantially stationary, rotating about the z-axis or horizontally moving each of thecurved mirrors108 while correspondinglens array122/light emitter array103 are maintained substantially stationary, tilting themirror array106/lens array122/light emitter array103 structure as a unit about the z-axis direction, or combinations thereof. Accordingly, the identical images generated by each of thecurved mirror108/light emitter102/lens124 sets and, consequently, the displayed image to the viewer, may be formed by a combination of horizontal and vertical scanning in conjunction with modulation of thelight emitters102.
• One embodiment of a control system that may be used to physically scan each of thelight emitters102 of thelight emitter array103 is shown inFIG. 7. Acontrol system300 includes asignal processor304 that receives a video signal V_IMcorresponding to an image. Thesignal processor304 extracts digital data representing lines of the image. For example, where the video signal V_IMis an analog signal, a conventional analog-to-digital converter may provide the digital data. Where the video signal V_IMcomprises digital data, the digital information may be extracted directly. The digital image data generated by thesignal processor304 is segmented into groups of data, where each group contains data representing a single line of the image. Each group of data corresponding to a line is stored in aline buffer306.
• Thesignal processor304 also extracts horizontal and vertical synchronization signals HSYNC, VSYNC, respectively. The horizontal synchronization signal HSYNC is generated after each line of the image. After each horizontal synchronization signal HYSNC, a line of image data is retrieved from theline buffer306 and provided to a digital-to-analog (D/A)converter310. (Theline buffer306 operates in synchronism with a clock signal, which has been omitted fromFIG. 7 in the interest of clarity). The D/A converter310 converts the digital data to an analog signal that is amplified at anamplifier314 and applied to each of thelight emitters102 of thelight emitter array103.
• The HSYNC signal is applied to aphase lock loop330, which includes aphase detector334 that compares the phase of the HSYNC signal to the phase of a feedback signal V_F. The phase detector outputs an error signal V_Ehaving a magnitude corresponding to the difference between the phase of the feedback signal V_Fand the phase of the HSYNC signal. This error signal V_Eis amplified and low-pass filtered by aloop filter338 to generate a control signal V_Cthat is used to control the frequency of the signal generated by a voltage controlled oscillator (“VCO”)340. The feedback signal V_Fis generated by coupling the output of theVCO340 through afrequency divider344. Thefrequency divider344 divides the frequency of the signal from the output of theVCO340 by “N”, where N is the number of pixels in each line of the image. Therefore, theVCO340 outputs N pulses for each HSYNC pulse. Each of the N pulses increments a pixel counter324 a digital count from the count sequentially increments. The count from thecounter324 is applied to each of thehorizontal actuators325, which move correspondinglight emitters102 horizontally from a position corresponding to a first pixel to a position corresponding to a last pixel. Thus, as the analog image signal for each line is applied to thelight emitters102, thelight emitters102 are scanned horizontally.
• The HSYNC pulse occurring after each line is also applied to aline counter308, which generates a digital value corresponding to the line of analog signals currently being applied to thelight emitters102. This digital value is applied to each of thevertical actuators350, which move correspondinglight emitters102 vertically to a new position corresponding to the value of a digital count from theline counter308. Thelight emitters102 are scanned horizontally at this new vertical position, and the process is repeated until the entire image is generated. Theline counter308 is then reset by the vertical synchronization (“VSYNC”) pulse, which occurs at the start of each image frame.
• In an alternative embodiment, thecontrol system300 may also be adapted to physically scan themirror array106/light emitter array102 structure of thedisplay100, thelight emitter array102/lens array122 structure of thedisplay120, and themirror array106/light emitter array102/lens array122 structure of thedisplay128 as a unit. In such an adaptation, only a large single actuator or set of actuators is needed.
• FIG. 8 shows a scannedbeam display400 according to an embodiment that is in the form of a see-through display physically mounted in a pair of eyeglasses. Thedisplay400 includes a pair of generallyoval holders404, each of which supports any of the previously described display embodiments. For example,respective holders404 may support themirror array106/light emitter array102 structure of thedisplay100, thelight emitter array102/lens array122 structure of thedisplay120, or themirror array106/light emitter array102/lens array122 structure of thedisplay128. Theholders404 may also support a pair of lenses132 positioned in front of thedisplays100,120, and128 such as, for example, corrective lenses (correcting nearsightedness or farsightedness), sunglass lenses, polarizing lenses or another suitable lens. Theholders404 are connected together using abridge406.Earbows408 are attached to the outer portions of each of theholders404 and extend away from therespective holders404. Theearbows408 are configured so that thedisplay400 may be worn on a viewer's head.
• In the discussion above, beams collimated by the array of mirrors and/or lenses were, for the sake of clarity, treated as if they were all substantially parallel. For cases where there are plural light emitters corresponding to each curved mirror and/or lens; and/or in cases where there is tolerance in the placement of light sources relative to the corresponding curved mirror and/or lens, beams emitted from adisplay100 ofFIG. 1, display120 ofFIG. 5 or adisplay128 ofFIG. 6 may not, in fact, be parallel.FIG. 9 is a diagram showing three sets of respective beams, each corresponding to a different one of a triad of light emitters emitted in (generally exaggerated) non-parallel directions. For the sake of clarity, only the beams from a single emitter corresponding to each mirror are shown. It will be understood that beams corresponding tobeam126acemitted bycurved mirror108aare emitted bymirrors108band108c,etc.
• At an instant in time, light emitted bylight emitter102acis reflected bymirror108ain abeam126acin a first direction, light emitted bylight emitter102bbis reflected bymirror108bin abeam126bbin a second direction, and light emitted bylight emitter102cais reflected bymirror108cin abeam126cain a third direction (assuming the mirrors are scanning synchronously). According to one embodiment,light emitter102ac(andlight emitters102bcand102cc,not indicated) is a blue light source,light emitter102bb(andlight emitters102aband102cb,not indicated) is a green light source, andlight emitter102ca(andlight emitters102aaand102ba,not indicated) is a red light source. Thus at an instant in time corresponding toFIG. 9 (again, assuming synchronous scanning of the mirrors108); red light beams are emitted in a first direction parallel tobeam126cafrom each of themirrors108a,108b,and108c;green light beams are emitted in a second direction parallel tobeam126bbfrom each of themirrors108a,108b,and108c;and blue light beams are emitted in a third direction parallel tobeam126acfrom each of themirrors108a,108b,and108c.This may be appreciated more fully by reference toFIG. 10 where blue light produced bylight emitters102ac,102bc,and102ccis reflected by respective, synchronously scannedcurved mirrors108a,108b,and108cin corresponding parallel, substantially collimatedblue beams126ac,126bcand126cc.Similarly,FIG. 11 shows a different instant in time when green light produced bylight emitters102ab,102bb,and102cbis reflected by respective, synchronously scannedcurved mirrors108a,108b,and108cin corresponding parallel, substantially collimatedgreen beams126ab,126bband126cb.FIG. 12 shows a different instant in time when red light produced bylight emitters102aa,102ba,and102cais reflected by respective, synchronously scannedcurved mirrors108a,108b,and108cin corresponding parallel, substantially collimatedblue beams126aa,126baand126ca.
• It is noted that while the respective red, green, and blue light beams point along a similar axis at different points in time, they do so, according to some embodiments, at time intervals short enough that every pixel in the display is able to be addressed at some point during a frame cycle by each of the curved mirror/light emitter pairs. This may be appreciated more fully by reference toFIGS. 13, 14, and14 where respectively at different instants in time corresponding to the indicated positions ofmirror108a;green, red, andblue emitters102ab,102aa,and102acare modulated to produce respective green, red, and blue signals associated with a particular pixel at a position corresponding to the particular common direction ofrespective beams126ab,126aa,and126ac.In this way, a full color pixel may be produced at each location by varying the timing of modulating laterally displaced (non-superpositioned)light emitters102 corresponding to eachmirror108. Similar techniques may be used for scanned emitters or scanned lenses.
• Similarly, the timing of emitter modulation may be modified to compensate for misalignment of one or more of theemitter102,mirror108, and/orlens124. Such timing may be determined after assembly during a calibration step and/or in the field to accommodate variation or drift in alignment. As indicated above, timing may be varied between emitter/mirror/lens pairs (triplets) to compensate for asynchronous scanning of the assemblies.
• FIG. 16 shows a block diagram of asystem2702 according to an embodiment, such as a camera, that uses a scannedbeam display2704 configured as one of the aforementioned scanned beam displays to provide images to the eye of aviewer115. An optional digitalimage capture subsystem2706 is controlled by amicrocontroller2708 to continuously or selectively capture still or video images according to user control received viauser interface2710. According to the wishes of the user, images or video may be stored inlocal storage2712 and/or alternatively may be sent to an external system through input/output interface2714. Thesystem2702 may be controlled to display a live image that is received by theimage capture system2706 or alternatively may be controlled to display stored images or video retrieved from thestorage2712.
• FIG. 17 shows a block diagram of amedia viewing system2802 that uses the scannedbeam display2704 to provide images to the eye of aviewer115 according to an embodiment. Themedia viewing system2802 receives images frommedia delivery infrastructure2804, which may for example include video or still image delivery or generation services over the Internet, a cellular telephone network, a satellite system, terrestrial broadcast or cable television, a plug-in card, a CD or DVD, or other media sources known to the art. For example, themedia delivery infrastructure2804 may include a video gaming system for providing a video gaming image, a digital camera, or a recorded media player. In the embodiment ofFIG. 17, anaccess point2806 provides a signal viawireless interface2808 to an input/output of themedia viewer2802 via awireless interface2810 interfaced to the remainder of themedia viewer2802 viacommunication interface2714. As used herein, the term communication interface may be used to collectively refer to the wireless interface2810 (e.g., an antenna as shown) and the radio and/or other interface to which it is connected. Media may be delivered across the communication interface in real time for viewing on thedisplay2704, or may alternatively be buffered by themicrocontroller2708 inlocal storage2712. User controls comprising auser interface2710 may be used to control the receipt and viewing of media. Themedia viewing system2802 may for example be configured as a pocket media viewer, a cellular telephone, a portable Internet access device, or other wired or wireless device.
• Although some of the embodiments have been described as using curved mirrors, according to an alternative embodiment, a diffractive optical element may be substituted for the curved mirrors described herein. It will be understood that, as modifications to the mirror shape such as adaptation to a Fresnel type mirror remain within the scope, so too does the adaptation to a diffractive element of arbitrary shape. In the interest of brevity and clarity, the term “curved mirror” will be understood to include such alternative mirror types.
• Although the invention has been described with reference to the disclosed embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For example, although scanning of the various embodiments have been described with reference to “vertical” and “horizontal” directions, it will be understood that scanning along other orthogonal and non-orthogonal axes may be used instead. Such modifications are well within the skill of those ordinarily skilled in the art. Accordingly, the invention is not limited except as by the appended claims.

Claims (58)

1. A scanned light display system, comprising:

a light emitter array having a plurality of light sources operable to emit diverging light;

an array of collimating elements, each of the collimating elements corresponding to at least one of the light sources and positioned to receive at least a portion of the diverging light emitted from the corresponding at least one of the light sources, each of the collimating elements configured to substantially collimate the received diverging light into respective beams; and

an actuator system coupled to at least one of the light emitter array and the array of collimating elements, the actuator system being operable to move at least one of the light emitter array and the array of collimating elements to scan the respective beams to provide an image, wherein the image appears substantially fixed to a viewer as the viewer's eye moves relative to the array of collimating elements.

2. The scanned light display system ofclaim 1 wherein each of the collimating elements comprises a curved mirror.

3. The scanned light display system ofclaim 2 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding one of the curved mirrors.

4. The scanned light display system ofclaim 3 wherein each of the actuators is operable to rotate the corresponding one of the curved mirrors about at least one axis.

5. The scanned light display system ofclaim 3 wherein each of the actuators is operable to move the corresponding one of the curved mirrors in at least one direction.

6. The scanned light display system ofclaim 2 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding at least one of the light sources.

7. The scanned light display system ofclaim 6 wherein each of the actuators is operable to move the corresponding at least one of the light sources in at least one direction.

8. The scanned light display system ofclaim 6 wherein each of the actuators is operable to move the corresponding at least one of the light sources in a manner that maintains the corresponding at least one of the light sources substantially on a focal surface of the corresponding curved mirror.

9. The scanned light display system ofclaim 1 wherein the actuator system is operable to rotate the array of collimating elements and the light emitter array as a unit about at least one axis.

10. The scanned light display system ofclaim 1 wherein each of the collimating elements comprises a lens.

11. The scanned light display system ofclaim 10 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding one of the lenses.

12. The scanned light display system of claims11 wherein each of the actuators is operable to rotate the corresponding one of the lenses about at least one axis.

13. The scanned light display system of claims11 wherein each of the actuators is operable to move the corresponding one of the lenses in at least one direction.

14. The scanned light display system ofclaim 1 wherein each of the collimating elements comprises a curved mirror and lens pair, the curved mirror positioned to reflect the emitted diverging light to the lens which is configured to substantially collimate the light reflected from the curved mirror.

15. The scanned light display system ofclaim 14 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding one of the curved mirrors.

16. The scanned light display system of claims15 wherein each of the actuators is operable to rotate the corresponding one of the curved mirrors about at least one axis.

17. The scanned light display system of claims15 wherein each of the actuators is operable to move the corresponding one of the curved mirrors in at least one direction.

18. The scanned light display system ofclaim 14 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding one of the lenses.

19. The scanned light display system of claims18 wherein each of the actuators is operable to rotate the corresponding one of the lenses about at least one axis.

20. The scanned light display system of claims18 wherein each of the actuators is operable to move the corresponding one of the lenses in at least one direction.

21. The scanned light display system ofclaim 14 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding at least one of the light sources.

22. The scanned light display system of claims21 wherein each of the actuators is operable to move the corresponding at least one of the light sources in a manner that maintains the corresponding at least one of the light sources substantially on a focal surface defined by the corresponding curved mirror and lens pair.

23. The scanned light display system ofclaim 1 wherein the actuator system comprises a plurality of actuators, each of the actuators coupled to a corresponding one of the collimating elements.

24. The scanned light display system ofclaim 1 wherein each of the respective beams is laterally spaced apart from an adjacent beam.

25. The scanned light display system ofclaim 1 wherein each of the beams abuts an adjacent beam.

26. The scanned light display system ofclaim 2 wherein each of the curved mirrors has a focal surface, and the at least one corresponding light sources are positioned substantially at the corresponding focal surface.

27. The scanned light display system ofclaim 26 wherein each of the curved mirrors is a spherical mirror and the focal surface is a focal sphere.

28. The scanned light display system ofclaim 1 wherein at least one of the light sources comprises one of a single monochrome source, a plural monochrome source, an RGB triad, and an RGBG quadrad.

29. The scanned light display system ofclaim 1 wherein at least one of the light sources comprises one of an organic light emitting diode, a surface emitting light emitting diode, an edge emitting light emitting diode, a laser diode, a dpss laser, photoluminescent spot, a reflector, and a fiber-optic source.

30. The scanned light display system ofclaim 1 wherein the light sources are operable to be modulated responsive to a video image.

31. The scanned light display system ofclaim 1 wherein the array of collimating elements comprises an at least partially transparent array of collimating elements.

32. The scanned light display system ofclaim 2 wherein each of the curved mirrors comprises a spherical mirror.

33. The scanned light display system ofclaim 2 wherein each of the curved mirrors comprises a Fresnel mirror.

34. The scanned light display system ofclaim 2 wherein each of the curved mirrors comprises a diffractive mirror.

35. The scanned light display system ofclaim 1 wherein the actuator system and the light emitter array are operable to synchronously scan each of the respective beams.

36. The scanned light display system ofclaim 1 wherein the actuator system and the light emitter array are operable to asynchronously scan each of the respective beams.

37. The scanned light display system ofclaim 1 wherein the actuator system is operable to scan each of the respective beams so that each of the collimating elements provides an identical image.

38. The scanned light display system ofclaim 1, further comprising a control system coupled to the light sources and the actuator system, the control system being operable to couple signals to the light sources and the actuator system.

39. The scanned light display system ofclaim 1, further comprising an image capture system.

40. The scanned light display system ofclaim 1, further comprising an image generation system and wherein the actuator system is operable to scan the respective beams to provide the image responsive to a signal from the image generation system.

41. The scanned light display system ofclaim 1 wherein the image generation system comprises one of a video gaming system, a digital camera, a recorded media player, and a television receiver.

42. A method of providing an image to a viewer, comprising:

emitting light from a plurality of light sources;

substantially collimating the light emitted from each of the light sources using corresponding collimating elements to form respective beams; and

scanning the respective beams to provide the image to the viewer, wherein the image appears substantially fixed to the viewer as the viewer's eye moves relative to the collimating elements.

43. The method ofclaim 42 wherein each of the collimating elements comprise curved reflecting surfaces and wherein the act of substantially collimating the light emitted from each of the light sources from corresponding collimating elements to form respective beams comprises reflecting the light emitted from each of the light sources from a corresponding one of the curved reflecting surfaces.

44. The method ofclaim 42 wherein each of the collimating elements comprise a curved reflecting surface and lens pair and wherein the act of substantially collimating the light emitted from each of the light sources from corresponding collimating elements to form respective beams comprises reflecting the light emitted from each of the light sources from a corresponding one of the curved reflecting surfaces and passing the reflected light through a corresponding one of the lenses.

45. The method ofclaim 42 wherein each of the collimating elements comprise at least one lens and wherein the act of substantially collimating the light emitted from each of the light sources from corresponding collimating elements to form respective beams comprises passing the light emitted from each of the light sources through a corresponding one of the lenses.

46. The method ofclaim 42 wherein the act of scanning the respective beams to provide an image to the viewer comprises moving each of the light sources and the corresponding collimating elements relative to each other.

47. The method ofclaim 46 wherein each of the collimating elements comprises a curved reflecting surface and wherein the act of moving each of the light sources and corresponding collimating elements relative to each other comprises moving each of the light sources along a path substantially on a focal surface of the corresponding curved reflecting surface.

48. The method ofclaim 46 wherein each of the collimating elements comprises a curved reflecting surface and wherein the act of moving the each of the light sources and corresponding collimating elements relative to each other comprises rotating each of the curved reflecting surfaces about at least one axis.

49. The method ofclaim 46 wherein each of the collimating elements comprises a curved reflecting surface and wherein the act of moving the each of the light sources and corresponding collimating elements relative to each other comprises moving each of the curved reflecting surfaces in at least one direction.

50. The method ofclaim 42 wherein the act of scanning the respective beams to provide an image to the viewer comprises rotating the plurality of light sources and the corresponding collimating elements as a unit about at least one axis.

51. The method ofclaim 46 wherein each of the collimating elements comprises a lens and wherein the act of moving each of the light sources and corresponding collimating elements relative to each other comprises moving each of the light sources while each of the lenses is maintained substantially stationary.

52. The method ofclaim 46 wherein each of the collimating elements comprises a lens and wherein the act of moving the each of the light sources and corresponding collimating elements relative to each other comprises rotating each of the lenses about at least one axis.

53. The method ofclaim 46 wherein each of the collimating elements comprises a lens and wherein the act of moving the each of the light sources and corresponding collimating elements relative to each other comprises moving each of the lenses in at least one direction.

54. The method ofclaim 46 wherein each of the collimating elements comprise a curved reflecting surface and lens pair and wherein the act of moving each of the light sources and corresponding collimating elements relative to each other comprises moving each of the light sources along a path substantially on a focal surface defined by the corresponding curved reflecting surface and lens pair.

55. The method ofclaim 42 wherein the act of scanning the respective beams to provide an image to the viewer comprises rotating the plurality of light sources and the corresponding collimating elements as a unit about at least one axis.

56. The method ofclaim 42, further comprising scanning each of the beams synchronously.

57. The method ofclaim 42, further comprising scanning each of the beams asynchronously.

58. The method ofclaim 42, further comprising modulating the plurality of light sources.

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