Projection systems project and reflect images off of a screen. Ambient light that is also reflected off the screen may reduce image contrast. Attempts to reduce the reflection of ambient light may reduce brightness of the reflected images.
Screen 22 is further configured to cycle between all of the different reflective states (i.e., (1) red, green and blue or (2) cyan, magenta and yellow) at a frequency greater than a flicker fusion frequency of an observer. In one embodiment, screen 22 is configured to cycle between such states at least 50 times per second or 50 hertz. In one particular embodiment, screen 22 cycles through the different reflective states at a frequency of at least about 72 hertz.
Projector 24 comprises a device configured to project light towards surface 30 of screen 22 such that the incident light is reflected from screen 22 and is viewable by an observer, such as a person or electronics like a web cam or sensor. Projector 24 is further configured to change between different projection states in which different colored light is projected towards screen 22. In particular, projector 24 is configured to change between different projection states in which projector 24 projects different colors of light corresponding to the different colors of light that may be reflected by screen 22 in its different screen reflective states. For example, in one embodiment, projector 24 is configured to change between a first projection state in which red colored light is projected and green and blue colored light are not projected, a second projection state in which green colored light is projected and blue and red light are not projected and a third projection state in which blue colored light is projected while red and green light are not projected. In yet another embodiment, projector 24 may alternatively be configured to change between projection states in which other colors are projected. For example, in another embodiment, projector 24 may alternatively be configured to change between projection states in which cyan, magenta and yellow colored light are projected.
In one embodiment, projector 24 may comprise a digital light processing (DLP) projector. In other embodiments, projector 24 may comprise a 35 millimeter projector, an overhead projector or other devices configured to project images of light upon screen 22. In other embodiments, projector 24 may also be configured to project other wavelengths of electromagnetic radiation such as infrared light or ultraviolet light and the like.
A light source, such as ambient light source 26 comprises a source of ambient light for the environment of projector 24 and screen 22. Ambient light source 26 is configured to rapidly change or flicker between different source states in which different colored light is provided to the environment of screen 22. According to one embodiment, ambient light source 26 is configured to change between different source states such that when screen 22 is reflecting a first colored light, ambient light source 26 is providing another color or colors of light and not providing the color of light beam being reflected by screen 22. In yet another embodiment, ambient light source 26 may be configured to change between the different source states based additionally upon the color or colors of light being projected by projector 24. For example, ambient light source 26 is configured to change between the different source states such that when projector 24 is projecting a first colored light and screen 22 is reflecting a first colored light, ambient light source 26 is providing another color or other colors of light and not providing or blanking the color of light being projected by projector 24.
In one embodiment, ambient light source 26 is configured to change between a first source state in which green colored light is provided and red and blue light are not provided, a second source state in which blue light is provided and red and green light are not provided and a third source state in which red colored light is provided while green and blue light are not provided. In yet another embodiment, ambient light source 26 is configured to change between a first source state in which green and blue colored light are provided and red light is not provided, a second source state in which red and blue light are provided and green colored light is not provided and a third source state in which red and green colored light are provided while blue colored light is not provided. In yet another embodiment, ambient light source 26 is configured to selectively provide other colors of light such as cyan, magenta and yellow light.
Ambient light source 26 is configured to cycle through its different source states at a frequency of at least 50 hertz. In one embodiment, light source 26 is configured to cycle between the different source states at a frequency of at least about 72 hertz. In one particular embodiment, ambient light source 26 may also be configured to change to a source state in which white light is provided.
Examples of ambient light source 26 include solid state emitters configured to emit different colors of light, such as different colored light emitting diodes. In other embodiments, ambient light source 26 may comprise generally continuous light emitters such as continuous incandescent lamps that are additionally provided with a mechanical or electrical filter such that the color of light being projected by projector 24 and being reflected by screen 22 is filtered out at the ambient light source 26. In still other embodiments, ambient light source 26 may comprise a window having a mechanical or electrical filter such that different colors of light are selectively transmitted through the window while other colors of light are selectively filtered. For example, in one embodiment, ambient light source 26 may comprise a window having a filter that changes between a first filter state in which red colored light is filtered, a second filter state in which green colored light is filtered and a third filter state in which blue colored light is filtered with the remaining colors of light being transmitted through the window.
According to one embodiment, ambient light source 26 comprises a single source of ambient light which cycles through different source states at a frequency greater than or equal to a flicker fusion frequency of observers. In another embodiment, ambient light source 26 may comprise multiple sources of ambient light which are synchronized and in phase with one another, wherein the multiple sources cycle through all the colors at a common frequency or multiples of a common frequency greater than or equal to a flicker fusion frequency of an observer. In still another embodiment, ambient light source 26 may comprise multiple sources of ambient light which cycle through all the colors at the same frequency or frequencies that are multiples of one another, but which are out of phase, wherein there is a common point or “notch” in time where the one or more colors are not being emitted from the ambient sources 26. For example if RED light is being reflected from the screen 22, multiple sources of ambient light source 26 may be flickering, may be providing multiple colors of light and may be out of phase as long as RED light is not being provided. For example, in one embodiment, ambient light source 26 may include a first light source flickering at 30 hertz and another ambient light source flickering at 30 hertz but 180 degrees out of phase with the first ambient light source. If coverage is sufficient, it may appear to an observer that the lights are running at 60 hertz in phase on the resulting lit surfaces because there is a 60 Hz component as well as a 30 Hz component, but sources may have smaller intensity notches to potentially be less irritating to observers.
Synchronizer 28 comprises one or more devices configured to synchronize or otherwise appropriately time the changing of screen 22, the ambient light source 26, and projector 24. In one embodiment, synchronizer 28 generates control signals for directing the changing of screen 22, projector 24 and ambient light source 26 such that screen 22 and projector 24 reflect and project the same color of light while ambient light source 26 provides one or more other colors of light.
As further shown by
In the particular example illustrated in
Overall, because screen 22 reflects the same color of light that is concurrently being projected by projector 24, the visible light projected by projector 24 is substantially reflected and received by an observer as an image. At the same time, because ambient light source 26 is providing a color of light that is not reflected by screen 22, such light is absorbed or scattered and is substantially not reflected back to an observer, maintaining contrast of the image reflected to the observer. However, the other colors of light provided by ambient light source 26 illuminate the ambient environment of screen 22. Because ambient light source 26 provides each of red, green and blue colored light at least once every 1/50 second or at a frequency greater than a flicker fusion frequency of an observer, such light provided by ambient light source 26 is perceived as white light by an observer. Because ambient light source 26 provides both green and blue light while projector 24 and screen 22 are projecting or reflecting red light, because ambient light source 26 provides both red and blue light while projector 24 and screen 22 are projecting and reflecting green light and because ambient light source 26 provides both red and green light while projector 24 and screen 22 are projecting and reflecting blue light, the brightness of ambient light provided by ambient light source 26 is enhanced as compared to those embodiments in which ambient light source provides a single color of light at a time. In other embodiments, ambient source 26 may alternatively provide a single color of light during the projection and reflection of a different colored light by projector 24 and screen 22.
As further shown by
As further shown by
In the particular example timing sequence 70 illustrated in
As with timing sequence 40, the use of timing sequence 70 by projection system 20 results in enhanced image contrast with ambient lighting. Because screen 22 in states 82, 84 and 86 reflects the particular light being projected by projector 24 in states 72, 74 and 76, respectively, at a frequency greater than a flicker fusion frequency of an observer, screen 22 and projector 24 provide an observer with colored images. At the same time, because screen 22 in states 82, 84 and 86 does not reflect substantially any of the colored light provided by ambient light source 26 during corresponding states 92, 94 and 96, such light provided by ambient light source 26 is absorbed or scattered by screen 22 and does not reduce the contrast of the image being reflected from screen 22. However, the light provided by ambient light source 26 during states 92, 94 and 96 illuminates the environment of screen 22. Because ambient light source 26 provides red, green and blue light and cycles through such light at a frequency greater than the flicker fusion frequency of an observer, the ambient lighting provided by ambient light source 26 is perceived as white light. In other embodiments, light source 26 may alternatively provide less than all three of red, green and blue light, wherein the ambient lighting is perceived as being colored.
With the particular timing sequence 70 shown in
With the particular timing sequences 40, 70 and 100 illustrated in
The processing unit of synchronizer 128 communicates with screen 22 and ambient light source 26, as well as potentially with projector 24, by one of various communication modes such as electrical wire or cabling, optical wire or cabling, infrared or other wireless signals. The processing unit comprising synchronizer 128 may be configured to supply power in a controlled fashion so as to modulate operation of screen 22, projector 24 and ambient light source 26 or may supply electrical or optical signals directing components associated with screen 22, projector 24 and ambient light source 26 to modulate such devices or supply power to such devices in a controlled fashion to cause modulation of such devices. In one embodiment, synchronizer 128 may distribute data or synchronization information over existing electrical wiring such as an alternating current line, wherein screen 22, projector 24 and ambient light source 26 receive the data or synchronization information which serves as a timing and synchronization signal for screen 22, projector 24 and ambient light source 26. In such an embodiment, synchronizer 128 may be physically incorporated into screen 22, projector 24 or ambient light source 26. In other embodiments, synchronizer 128 may synchronize such components in other fashions.
Controller 242 comprises a processing unit configured to generate control signals directing the operation of screen 22 and projector 24 based upon signals received from sensor 240. In response to control signals from controller 242, screen 22 changes or modulates between reflectivity states such as states 52, 54, 56 or states 82, 84, 86 and 88. In one embodiment, controller 242 may be physically coupled to sensor 240 as a distinct unit connected to screen 22. In another embodiment, one or both of controller 242 and sensor 240 may be physically incorporated as part of screen 22.
Controller 244 comprises a processing unit configured to generate control signals directing the operation of projector 24 based upon signals from sensor 240. In particular, the operation of projector 24 is synchronized with the operation of screen 22 and the sensed source states of ambient light source 26.
Synchronizer 328 includes sensor 340, controller 342 and controller 344. Sensor 340 comprises a sensor configured to detect the flickering or modulation of screen 22. In one embodiment, sensor 340 may comprise an optical sensor. According to one exemplary embodiment, sensor 340 may comprise a phototransistor biased to operate with the speed and light reflectance levels of the screen. This photo transistor may be paired with its own light source such as an LED in a configuration that adequately biases and triggers the sensor 340 by the change in reflectivity of the screen. This light source would reduce light interference from other sources including the out-of-sync ambient light source. Another configuration may include the flickering light source in such a way whereby the combination and state of the light source and screen reflectance could generate an error signal which the synchronizer could use to keep the flickering light in sync with the free running frequency of the screen. According to another embodiment, sensor 340 may comprise an electrical or other sensor directly associated with screen 22 to detect a characteristic of screen 22 which corresponds to its flickering. Sensor 340 communicates signals based upon the sensed or detected flickering to controller 342.
Controller 342 comprises a processing unit configured to generate control signals directing the flickering or modulation of ambient light source 26 based upon signals received from sensor 340. In particular, controller 342 generates control signals directing ambient light source 26 to be in states 62, 64 and 66 when screen 22 is in the reflectivity states 52, 54 and 56, respectively. In embodiments where synchronizer 328 operates under timing sequence 70, controller 342 generates control signals directing ambient light source 26 to be in states 92, 94, 96 and 98 when signals from sensor 340 indicate that screen 22 is in states 82, 84, 86 and 88, respectively. In one embodiment, sensor 340 and controller 342 may be incorporated as an independent unit configured to communicate with ambient light source 26. In still another embodiment, sensor 340 and/or controller 342 may alternatively be physically incorporated as part of ambient light source 26. In yet another embodiment, sensor 340 and/or controller 342 may alternatively be physically incorporated as part of a wall switch which controls ambient light source 26.
Controller 344 comprises a processing unit configured to generate control signals directing the operation of projector 24 based upon signals received from sensor 340 or received from source 26. In embodiments where synchronizer 428 operates using timing sequence 40, controller 344 generates control signals directing projector 24 to be in states 42, 44 and 46 when screen 22 is in states 52, 54 and 56 and when source 26 is in states 62, 64 and 66, respectively. In embodiments where synchronizer 328 operates according to timing sequence 70 shown in
Synchronizer 428 includes sensor 440, controller 442 and controller 444. Sensor 440 comprises a sensor configured to detect colored light projected by projector 24. In one embodiment, sensor 440 may comprise an optical sensor. According to one embodiment, sensor 440 is incorporated as part of screen 22. In yet another embodiment, sensor 440 may be provided at other locations anywhere along a path of light from projector 24 to screen 22. Based upon the sensed color of light projected by projector 24, sensor 440 generates signals which are communicated to controllers 442 and 444.
Controller 442 comprises a processing unit configured to generate control signals directing the operation of screen 22 based upon signals received from sensor 440. In response to control signals from controller 442, screen 22 changes or modulates between reflective states such as states 52, 54, 56 or states 82, 84, 86 and 88. In one embodiment, controller 442 may be physically coupled to sensor 440 as a distinct unit connected to screen 22. In another embodiment, one or both of controller 442 and sensor 440 may be physically incorporated as part of screen 22.
Controller 444 comprises a processing unit configured to generate control signals directing the operation of ambient light source 26 based upon signals received from sensor 440. In particular, controller 444 generates control signals directing ambient light source 26 to be in states 62, 64 and 66 when screen 22 is in reflective states 52, 54 and 56, respectively. In embodiments where synchronizer 428 operates under timing sequence 70, controller 442 generates control signals directing ambient light source 26 to be in states 92, 94, 96 and 98 when signals from sensor 440 indicate that projector 24 is in states 72, 74, 76 and 78, respectively. In other embodiments, controller 442 may generate control signals based upon signals received from controller 442 rather than based upon signals from sensor 440. In still other embodiments, controller 442 may generate control signals directing screen 22 based upon signals from controller 444 instead of basing such control signals upon input from sensor 440. In still other embodiments, controller 442 and controller 444 may be provided by a single processing unit connected to both screen 22 and ambient light source 26.
In each of the systems schematically shown and described with respect to
Reflective layers 542 comprise layers of visible light reflecting material supported by back substrate 540. According to one example embodiment, layers 542 are formed from a transmissive color filter material formed on top of a reflective metallic film such as aluminum. In other embodiments, layer 542 may be formed from other materials such as reflective color patterns. For example, colored dots may be patterned upon substrate 540 by inkjet printing. In still other embodiments, light transmissive color filter materials may be provided adjacent to electrode layers 555, such as between front substrate 550 and electrode layers 555. In another embodiment, reflective layer 542 may alternatively be configured so as to reflect substantially all light without substantially filtering or absorbing light.
Reflective layers 542a, 542b and 542c are configured to reflect distinct colors or wavelengths of visible light such as red, green and blue or such as cyan, magenta and yellow colored light, respectively. In other embodiments, reflective layers 542a, 542b and 542c may comprise distinctly colored filters over a reflective layer. Although reflective layers 542a, 542b and 542c are illustrated as generally located proximate to back substrate 540, reflective layers 542a, 542b and 542c may alternatively be located adjacent to active layer 560 or between active layer 560 and back substrate 540 while still permitting electrode layers 545 to operate as described below. In other embodiments, reflective layers 542a-542c may themselves be electrically conductive, permitting reflective layers 542a, 542b and 542c to be positioned on electrode layers 545a-545c, respectively, adjacent active layer 560.
Electrode layers 545 comprise layers of electrically conductive material configured to be electrically charged so as to apply an electric field across active layer 560. Electrode layers 545a, 545b, 545c are configured to selectively apply distinct voltages across active layer 560 to control the opacity or translucency of adjacent portions of active layer 560. In the particular embodiment illustrated, electrode layers 545a, 545b and 545c are formed from the transparent or translucent electrically conductive materials and overlie reflective layers 542a, 542b and 542c of reflective layer 542. For example, one embodiment, electrode layers 545 may comprise a conductive material such as indium tin oxide (ITO) or polyethylenedioxythiophene (PEDOT). In other embodiments, electrode layers 545a, 545b and 545c may themselves be configured to reflect different colors of light such as red, green and blue or such as cyan, magenta and yellow, enabling reflective layer 542 to be omitted. In other embodiments, electrode layers 545 may be formed from other electrically conductive materials.
Front substrate 550 comprises a support structure for electrode layers 555. Front substrate 550 is formed of an optically transparent and clear dielectric material. In one embodiment, front substrate 550 may be formed from an optically clear and flexible dielectric material such as polyethylene terephthalate (PET). In other embodiments, front substrate 550 may be formed from other transparent dielectric materials that may be inflexible such as glass.
Electrode layers 555 comprise layers of transparent or translucent electrically conductive material formed upon front substrate 550. Electrode layers 555 are configured to be charged so as to cooperate with electrode layers 545 to create an electric field across active layer 560. Electrode layers layers 555a, 555b and 555c configured to be independently charged to distinct voltages to create differing electrical fields across active layer 560. In one embodiment, electrode layers 555 are formed from a transparent conductor such as indium tin oxide (ITO) or polyethylenedioxythiophene (PEDOT). In other embodiments, other transparent conductive materials may be used. Electrode layers 555 and electrode layers 545 are each electrically connected to synchronizer 128 which controls the charges created across electrode layers 545 and 555.
In one embodiment, electrode layers 545a-545c and layers 555a-555c of each pixel 530 are configured to be independently charged. In one embodiment, electrode layers 545a-545c and electrode layers 555a-555c of each of pixels 530 are electrically connected to a voltage source by an active matrix of electrical switching devices provided in electrode layers 545, back substrate 540 or another active back plane. Examples of switching devices may include thin film transistors and metal-insulator-metal devices.
In other embodiments, electrode layers 545a-545c of each pixel 530 may be configured to be independently charged to distinct voltages with the other electrode layers not configured in this fashion. In such an embodiment, electrode layers 555 may alternatively comprise a single continuous layer of electrically conductive material extending opposite to electrode layers 545a-545c. In another embodiment, electrode layers 555a-555c of each pixel 530 may be configured to be independently charged with the other electrode layers not configured in this fashion. In such an embodiment, electrode layers 545a-545c may alternatively be replaced with a single continuous layer of electrically conductive material extending across each of reflective layers 542a-542c.
Active layer 560 comprises a layer of material configured to change its transparency and reflectivity in response to changes in an applied voltage or charge. In one embodiment, active layer 560 may change from a transparent or translucent state, allowing light to pass through active layer 560 and to be reflected from at least one of reflective layers 542a-542c of electrode layers 545, to a generally opaque state in which light is absorbed by active layer 560. According to one example embodiment, active layer 560 may comprise a dichroic dye doped polymer dispersed liquid crystal (PDLC) layer in which pockets of liquid crystal material are dispersed throughout a transparent polymer layer. In other embodiments, active layer 560 may comprise other materials such as electrochromic material, such as tungsten oxide or photochromic or electropheretic material.
Active layer 560 is generally disposed between electrode layers 545 and 555. In one embodiment, active layer 560 is a layer of material continuously extending and captured between electrode layers 545 and 555. For each pixel 530, active layer 560 includes regions 160a, 160b and 160c. Regions 160a-160c generally extend between electrode layers 545a, 555a, electrode layers 545b, 555b and electrode layers 545c, 555c, respectively, and independently respond to voltage changes across the corresponding electrode layers by changing translucency. Regions 160a, 160b and 160c are generally situated across from reflective layers 542a, 542b and 542c, respectively. As a result, the opacity or translucency of regions 160a, 160b and 160c effects how much, if any, incident light may reach and be reflected off of reflective layers 542a, 542b and 542c, respectively.
Coating layer 565 generally comprises one or more layers deposited or otherwise formed on front substrate 550 opposite to electrode layers 555. Coating layer 565 may comprise a front plane diffuser and may include an anti-reflection layer such as anti-glare surface treatment, an ambient rejection layer, such as a plurality of optical band pass filters such as those commercially available from 3M, or a series of micro lenses and/or partial diffuse layers. In other embodiments, coating layer 565 may be omitted.
In operation, synchronizer 128 (described above with respect to
As shown by
Optics 572 are generally positioned between light source 570 so as to condense light from light source 570 towards optics 574. In one embodiment, optics 572 may include a light pipe or integrating rod. Optics 574 comprises one or more lenses or mirrors configured to focus and direct light towards DMD 576. In one embodiment, optics 574 may comprise lenses which focus and direct the light. In another embodiment, optics 574 may additionally include mirrors which re-direct light onto DMD 576.
In one embodiment, DMD 576 comprises a semiconductor chip covered with a multitude of miniscule reflectors or mirrors which may be selectively tilted between “on” positions in which light is redirected towards lens 578 and “off” position in which light is not directed towards lens 578. The mirrors are switched “on” and “off” at a high frequency so as to emit a grayscale image. In particular, a mirror that is switched on more frequently reflects a light gray pixel of light while the mirror that is switched off more frequently reflects a darker gray pixel of light. In this context, “grayscale”, “light gray pixel”, and “darker gray pixel” refers to the intensity of the luminance component of the light and does not limit the hue and chrominance components of the light. The “on” and “off” states of each mirror are coordinated with colored light from light source 570 to project a desired hue of colored light towards lens 578. The human eye blends rapidly alternating flashes to see the intended hue of a particular pixel in the image being created. In the particular example shown, DMD 576 is provided as part of a DLP board 582 which further supports a processor 584 and associated memory 586. Processor 584 and memory 586 are configured to selectively actuate the mirrors of DMD 576. In other embodiments, processor 584 and memory 586 may alternatively be provided by or associated with controller 580.
Because ambient light sources 526 are changing so as to provide ambient colored light different than the color being projected by projector 524, the color contrast and intensity of light projected by projector 524 is not reduced or washed out by light from ambient light sources 526. As a result, less expensive or lower intensity light sources, such as light source 570 may be employed in projector 524. Because projector 524 facilitates the use of generally lower intensity light emitting diodes for light source 570, the cost and complexity of projector 524 is reduced.
Ambient light sources 526 either emit visual light or transmit visual light to the environment of screen 522 and projector 524. Ambient light sources 526A-526E change between distinct source states and cycle through such states, such as states 62, 64 and 66 or states 92, 94, 96 and 98 (shown in
Ambient light sources 526A and 526B selectively permit the transmission of visual light from another source, such as the sun. Ambient light source 526A generally comprises a window including a frame 616 and a pane 618 and light transmission modulator 602. Frame 616 supports pane 618 and may include electrical components of ambient light source 526A.
Pane 618 of
Light transmission modulator 602 extends across pane 618 so as to selectively block the transmission of light or to allow transmission of light through pane 618. In one embodiment, light transmission modulator 602 (shown in
Light transmission modulator 602 comprises a series of layers configured to selectively filter wavelengths of light being transmitted by modulator 602. In one embodiment, light transmission modulator 602 selectively filters light such that red light, green light or blue light are transmitted through modulator 602 while transmission of remaining colors of visible light are attenuated. As shown by
Those remaining elements of each pixel 630 of modulator 602 which correspond to elements of each pixel 530 of screen 522 are numbered similarly. Substrate 640 comprises a layer of transparent or translucent material serving as a base or foundation upon which filter layers 642 are deposited or otherwise formed. In the particular embodiment illustrated, substrate 640 is further formed from a dielectric material. In one embodiment, substrate 640 may be formed from an optically clear and flexible dielectric material such as polyethylene terephalate (PET). In other embodiments, substrate 640 may be formed from other transparent or translucent dielectric materials that may be inflexible such as glass.
Filter layers 642 comprise layers of one or more materials configured to filter certain wavelengths of visible light. In the embodiment illustrated, filter layer 642a comprises a layer of material configured to filter substantially all wavelengths of visible light except for red wavelengths of visible light. Filter layer 642b comprises one or more layers of one or more materials configured to filter substantially all wavelengths of visible light except for green wavelengths of visible light. Filter layer 642c comprises one or more layers of one or more materials configured to filter substantially all wavelengths of visible light except for blue wavelengths of visible light. In one embodiment, filter layers 642 may be formed from printed ink on PET. In other embodiments, filter layers 642 may be formed from other materials.
In operation, synchronizer 128 supplies alternating electrical current or charge as appropriate to one or more of electrode layers 545 and 555, individually, of each pixel 630 so as to selectively create electrical fields across individual regions 560a, 560b and 560c of active layer 560 to control the degree of light transmission or light attenuation by such regions 560a, 560b and 560c. By controlling which of regions 560a, 560b and 560c attenuate light versus which of such regions transmit light, synchronizer 128 also controls the resulting color of light emitted from each pixel 630. In such a manner, synchronizer 428 may change pixel 630 of modulator 602 so as to change a light source between different source states in which different colors of light, such as red, green and blue light, are provided.
For example, in one scenario, synchronizer 128 may cause an electrical field to be formed across region 560b by applying an alternating charge to one or both of conductive layers 545b and 555b. At the same time, little or no electrical field is formed across regions 560a and 560b. As a result, region 560 will transmit light while regions 560a and 560c will substantially attenuate the transmission of light. Consequently, light passing through substrate 640, filter layer 642b, region 560b of active layer 560, electrical layer 555b, substrate 550 and layer 565 will be emitted as green light. Regions 560a and 560c will block or attenuate transmission of light before or after passing through filter layers 642a and 642c. Thus, modulator 602 will filter substantially all light from a light emitter except for green light. By similarly controlling each of pixels 630 of modulator 602, synchronizer 428 may actuate modulator 602 to a green filter state. In a similar manner, synchronizer 428 may supply electrical charge to conductive layers 545 and 555 to actuate pixel 630 of modulator 602 to other filter states in which substantially all wavelengths of visible light except for red light or alternatively except for blue light are filtered. In other embodiments, modulator 602 may alternatively be in filter states in which one color of light is filtered out. For example, an electrical field may be created across more than one of regions 560a, 560b and 560c such that more than one of red, green and blue colored light is transmitted through modulator 602.
Ambient light source 526B includes window 626 and window shade 628. Window 626 comprises an opening through which light may pass to the environment of screen 522. In one embodiment, window 526 may include one or more transparent panes through which light may pass. In another embodiment, window 626 may include openings or at least partially transparent screens through which light may pass.
Window shade 628 comprises a device having a selectively transparent or selectively opaque window overlying portion 630. Portion 630 includes light transmission modulator 602 shown and described with respect to
In the embodiment shown in
Because portion 630 is flexible such that portion 630 may be rolled into a roll, shade 628 may comprise a pull-down shade which may be rolled up so as to extend across window 626 by different extents or so as to be completely retracted with respect to window 626. In other embodiments, shade 628 may comprise other configurations of shades or blinds having a portion 630 that overlies window 626 and includes light transmission modulator 602. For example, shade 628 may alternatively comprise a vertical blind, an accordion-style blind and the like.
Ambient light source 526C emits differently colored light and cycles through such colors at a frequency greater than a flicker fusion frequency of a human eye. Ambient light source 526C includes continuous light emitter 636 and cover 638. Continuous light emitter 636 comprises a source of continuous light such as an incandescent or fluorescent bulb. Light emitter 636 may be recessed within a wall or ceiling or may be partially enclosed by a housing 640.
Cover 638 extends between light emitter 636 and screen 522. Cover 638 is formed from one or more layers of transparent material and additionally includes light transmission modulator 602 (shown in
Ambient light source 526D emits differently colored light and cycles through such colors at a frequency greater than or equal to the flicker fusion frequency of a human eye. Ambient light source 526D includes continuous light emitter 646 and cover 648. Light emitter 646 generally comprises an elongate tube configured to continuously emit light. In one embodiment, light emitter 646 comprises a gas discharge light cell such as a fluorescent lighting tube.
Cover 648 comprises an elongate cylinder, tube or sleeve extending and positioned about lighting emitter 646. Cover 648 includes light transmission modulator 602 extending between emitter 646 and screen 522. In one embodiment, light transmission modulator 602 extends along a lower portion of cover 648 opposite a lower portion, such as the lower half, of light emitter 646.
In other embodiments, light transmission modulator 602 substantially extends about cover 648 and around or about light emitter 646. In one particular embodiment, cover 648 is removably positioned about light emitter 646, allowing light emitter 646 to be replaced without discarding cover 648. In another embodiment, cover 648 may be mounted to light emitter 646 or light transmission modulator 602 may be coated upon the tube of light emitter 646.
Light emitter 654 comprises an elongate tube configured to continuously emit light. In one embodiment, emitter 654 may comprise a gas discharge light cell such as a fluorescent lighting tube. In other embodiments, emitter 654 may alternatively comprise other elongate light emitting devices such as one or more elongate rows or arrays of light emitting diodes. Emitter 654 is stationarily supported by housing 652 substantially within cover 656.
Cover 656 comprises an elongate cylinder, tube or sleeve extending and positioned about emitter 654. Cover 656 is rotatably coupled or supported by housing 652 so as to rotate about emitter 654. Although a portion of cover 656 is illustrated as protruding from housing 652, in other embodiments, cover 656 may be completely recessed within housing 652. Cover 656 includes filters 664a, 664b and 664c (collectively referred to as filters 664). Filters 664 are each configured to filter a predetermined portion of the visible spectrum of electromagnetic radiation while permitting another portion of the visible spectrum of electromagnetic radiation emitted by emitter 654 to pass therethrough. In the particular example illustrated, filter 664a is configured to substantially filter out or attenuate wavelengths of visible light other than red wavelengths. Filter 664b is configured to substantially attenuate wavelengths of visible light but for green wavelengths. Filter 664c is configured to substantially attenuate wavelengths of visible light but for blue wavelengths. In one embodiment, filters 664a, 664b and 664c may be formed from dichotic materials. In other embodiments, filter 664 may be formed from other materials. Filters 664 cooperate with one another to encircle emitter 654. Although cover 656 is illustrated as including three filters 664, in other embodiments, cover 656 may alternatively include a greater number of filters. For example, in another embodiment, cover 656 may alternatively include a first red filter, a first green filter, a first blue filter, a second red filter, a second green filter and a second blue filter. In yet other embodiments, filter 656 may additionally include a transparent or translucent portion for enabling light source 526D′ to be actuated to state 98 when the timing sequence 70 shown in
Rotary actuator 658 (schematically shown) comprises a device configured to rotate cover 656 about emitter 654. In one embodiment, rotary actuator 658 may comprise a motor operably coupled to cover 656 by a gear train, chain and sprocket arrangement, belt and pulley arrangement and the like. In other embodiments, other forms of rotary actuators may be employed.
Controller 660 (schematically shown) comprises a processing unit in communication with rotary actuator 658 and configured to generate control signals directing rotary actuator 658 to rotate cover 656. In one embodiment, controller 660 generates control signals directing rotary actuator 658 to rotate cover 656 to successfully position filters 664a, 664b and 664c across opening 662 so as to cycle through each of filters 664 at a frequency greater than a flicker fusion frequency of a human eye (nominally 50 hertz). In the embodiment shown, controller 660 further generates control signals, based in part upon signals from synchronizer 128 (shown in
In the particular example shown, filters 664 are illustrated as being rotated about emitter 654 so as to change between different filter states such that light source 526D′ also changes between different source states in which different colors of light are provided. In other embodiments, filters 664 may have other configurations and may be selectively positioned in front of a continuous light emitter, such as light emitter 654, in other fashions.
Ambient light source 526E is configured to provide distinct colors of light and to cycle through all of the colors of light, such as red, green and blue, at a frequency greater than or equal to the flicker fusion frequency of a human eye. Ambient light source 526E generally comprises a lamp 656 and a lamp shade 658. Lamp 656 comprises a source of continuous light. For example, in one embodiment, lamp 656 may include an incandescent light bulb or a fluorescent bulb.
Lamp shade 658 is supported about the light bulb of lamp 656 and includes light transmission modulator 602 shown in
Ambient light source 526F comprises a device configured to provide distinct colors of light, such as red, green and blue, and to cycle through such colors of light at a frequency greater than or equal to a flicker fusion frequency of a human eye. Ambient light source 526F may comprise a solid state light emitting device such as a light emitting diode light bulb having an arrangement of light emitting diodes configured to sequentially emit different colors of light and a threaded base configured to charge and ground the light emitting diodes. Examples of such light emitting diode bulbs are those commercially available from Enlux Lighting of Mesa, Ariz., and those available from Ledtronics, Inc., of Torrance, Calif. However, unlike such light emitting diode bulbs as those commercially available, ambient light source 526F is configured to cycle through multiple distinct colors, such as red, green and blue, at a frequency greater than the flicker fusion frequency of a human eye. As a result, ambient light source 526 may be synchronized with changing of screen 522 to enhance contrast in the presence of ambient light.
Ambient light source 526G comprises a device configured to change between different filter states in which modulator 602 selectively filters colors of light such that light source 526E changes between different source states in which selected colors of light are not provided while other colors of light are provided. In particular, modulator 602 changes between different filter states such that light source 526E may operate with respect to projector 524 and screen 522 according to one of the example timing sequences shown in
As shown in
Support 670 supports light emitting diodes 672 which are electrically connected to conductive pins 674 and 676. Pin 674 is configured to be connected to a voltage source while pin 676 is configured to be electrically connected to ground. Support 670 and pins 674, 676 are specifically configured to mount within an existing socket 680 for a fluorescent tube or lamp. As a result, the fluorescent tube or lamp may be replaced with ambient light source 526G.
Controller 678 comprises a processing unit configured to generate control signals for selectively powering diodes 672 based at least in part upon signals received from synchronizer 128 (shown in
According to one embodiment, controller 678 generates control signals such that two of rows 671a, 671b and 671c are powered while the one row 671a, 671b, 671c which would otherwise emit a color of light corresponding to the color of light being reflected by screen 522 during the period of time is off. In one embodiment, controller 436 includes a power supply to provide positive DC or pulsing DC to diodes 672. Because ambient light source 526 may be synchronized with changing of screen 522 between different reflectivity states (as shown in
Overall, projection systems 20, 120, 220, 320, 420 and 520 may maintain the contrast of a projected image that is reflected from a screen while providing an observer of the image with ambient lighting. Because screens 22, 522 changes between different reflectivity states so as to reflect the same color of light being projected by projector 24 or 524, substantially all of the light projected by projector 24 or 524 is reflected back to an observer for enhanced image brightness. Because ambient light source 26, 526 is providing one or more colors of light that are not reflected by screen 22, 522 but are absorbed or scattered by screen 22, 522, image contrast is enhanced. At the same time, ambient light source 26, 526 provides enhanced ambient lighting to the environment of screen 522 and projection systems 20, 120, 220, 320, 420 and 520.
Although the present disclosure has been described with reference to example embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the claimed subject matter. For example, although different example embodiments may have been described as including one or more features providing one or more benefits, it is contemplated that the described features may be interchanged with one another or alternatively be combined with one another in the described example embodiments or in other alternative embodiments. Because the technology of the present disclosure is relatively complex, not all changes in the technology are foreseeable. The present disclosure described with reference to the example embodiments and set forth in the following claims is manifestly intended to be as broad as possible. For example, unless specifically otherwise noted, the claims reciting a single particular element also encompass a plurality of such particular elements.