PATENT DOCUMENT

Publication Number: US-8502926-B2
Application Number: US-57012009-A
Country: US
Kind Code: B2

Title: Display system having coherent and incoherent light sources

Abstract:
Embodiments are disclosed that allow light display systems, such as projectors, to be manufactured having lower power consumption, reduced speckling, and/or that are less expensive than conventional light projectors. In some embodiments, may include an incoherent light source and a coherent light source operating in concert with one another to produce a combined light beam that has similar wavelength contributions from the incoherent and coherent light sources.

Claims:
What is claimed is: 
     
       1. A system for displaying images comprising:
 an incoherent light source; and 
 a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, wherein the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources, wherein the coherent light source emanates a narrower band of wavelengths as compared to the incoherent light source, wherein an intensity level of the coherent light source is less than an intensity level of the incoherent light source, and wherein the intensity level of the coherent light source is used to fine tune an overall intensity of the combined beam of light. 
 
     
     
       2. A system for displaying images comprising:
 an incoherent light source; and 
 a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, wherein the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources, wherein the coherent light source emanates a narrower band of wavelengths as compared to the incoherent light source, wherein an intensity level of the coherent light source is less than an intensity level of the incoherent light source, the system further comprising a light sensor. 
 
     
     
       3. The system of  claim 2 , wherein the intensity level of the incoherent light source is used to calibrate the intensity level of the coherent light source. 
     
     
       4. A system for displaying images comprising:
 an incoherent light source; and 
 a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, wherein the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources, wherein the coherent light source emanates a narrower band of wavelengths as compared to the incoherent light source, wherein the incoherent light source is driven by a chrominance portion of a video signal. 
 
     
     
       5. A system for displaying images comprising:
 an incoherent light source; and 
 a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, wherein the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources, wherein the coherent light source emanates a narrower band of wavelengths as compared to the incoherent light source, wherein the coherent light source is driven by a luminance portion of a video signal. 
 
     
     
       6. A method of displaying images, comprising the operations of:
 outputting a first light from an incoherent light source; 
 outputting a second light from a coherent light source operating in concert with the incoherent light source, thereby producing a combined beam of light including similar wavelength contributions from the incoherent and coherent light sources; and 
 using the intensity level of the incoherent light source to calibrate the intensity level of the coherent light source. 
 
     
     
       7. The method of  claim 6 , further comprising setting an intensity level of the coherent light source to be less than an intensity level of the incoherent light source. 
     
     
       8. A method of displaying images, comprising the operations of:
 outputting a first light from an incoherent light source; 
 outputting a second light from a coherent light source operating in concert with the incoherent light source, thereby producing a combined beam of light including similar wavelength contributions from the incoherent and coherent light sources; 
 determining a chrominance of a projected image; 
 determining a luminance of the projected image; 
 setting the output of the incoherent light source based on the chrominance of the projected image; and 
 setting the output of the coherent light source based on the luminance of the projected image.

Description:
BACKGROUND OF THE INVENTION 
     I. Technical Field 
     The present invention relates generally to display systems, and more particularly to methods and apparatuses that provide coherent and incoherent lighting sources within the same display system. 
     II. Background Discussion 
     Electronic devices are ubiquitous in society and can be found in everything from wristwatches to computers. Many of these electronic devices include the ability to display images to the user of the electronic device, such as by projecting the displayed images through a lens onto a screen or backdrop. Conventional projectors include so called “laser projectors,” which render images using coherent laser light as opposed to projectors using incoherent incandescent light sources. While the laser display systems may offer greater resolution than non-laser based display systems, they often consume greater amounts of power. Because of their greater power consumption requirements, laser based display systems also may include complicated cooling circuitry and thus result in more bulky projection equipment. 
     Another issue with laser display systems versus non-laser based display systems is the so called “speckle” problem. “Speckling” refers to an interference in the intensity of highly coherent light, such as laser light, which may result from the laser striking a rough surface. The overall effect of speckle in laser display systems is that the image may appear grainy. Furthermore, laser light sources are often more costly than other non-laser light sources, making laser based display systems more expensive. Accordingly, display systems that embrace the desirable features of laser light sources while overcoming the undesirable features of non-laser light sources may be useful. 
     SUMMARY 
     Embodiments are disclosed that allow light display systems, such as projectors, to have lower power consumption, reduced speckling, and/or that are less expensive than conventional light projectors. In some embodiments, an incoherent light source may be optically coupled to a coherent light source to produce a combined coherent and incoherent beam of light for projecting images. In general, incoherent light sources, such as light emitting diodes (LEDs) or incandescent bulbs, emanate light waves across a broad spectrum (e.g., multiple wavelengths of light), whereas coherent light sources, such as lasers, are more precise and emanate light waves of a single wavelength. By combining light from the incoherent light source with the light from the coherent light source, the overall power level of the coherent light source in the combined light beam may be reduced while still perceiving a crisp, clear image. As a result of the lower power levels for the coherent light sources, the size and complexity of light projection systems may be reduced. 
     Some embodiments may take the form of a system for displaying images, wherein the system includes an incoherent light source and a coherent light source operating in concert with the incoherent light source to produce a combined beam of light, where the combined light beam includes similar wavelength contributions from the incoherent and coherent light sources. The term “operation in concert” as used herein is intended to refer to the coherent and incoherent light sources emanating at least one wavelength that is substantially the same at substantially the same time. 
     Other embodiments may take the form of a method of calibrating an image display system, wherein the method includes the operations of providing an image to one or more display circuits, setting a first intensity level for an incoherent light source, determining if an intensity of the projected image equals a desired intensity level, and, in the event that the intensity of the projected image does not equal the desired intensity, setting a second intensity level for a coherent light source. 
     Still another embodiment may be a method of projecting an image, wherein the method includes separating an image into first and second components, projecting the first component using an incoherent light source, and projecting the second component using a coherent light source, wherein the incoherent and the coherent sources concurrently generate similar wavelengths to render the image. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates one embodiment of a display system. 
         FIG. 2  illustrates an alternate embodiment of the display system. 
         FIG. 3  illustrates yet another alternate embodiment of the display system. 
         FIG. 4  illustrates a display system employing incoherent and coherent light sources. 
         FIG. 5  illustrates signals that may be conveyed to the incoherent and coherent light sources. 
         FIG. 6A  illustrates the overall intensity of the combination of the incoherent and coherent light sources. 
         FIG. 6B  illustrates an alternate representation of the intensity of the incoherent and coherent light sources. 
         FIG. 6C  illustrates yet another representation of the intensity of the incoherent and coherent light sources. 
         FIG. 7A  illustrates speckle with respect to coherent light sources. 
         FIG. 7B  illustrates speckle reduction as a result of employing incoherent and coherent light sources. 
         FIG. 8  illustrates operations for calibrating the coherent light source. 
     
    
    
     The use of the same reference numerals in different drawings indicates similar or identical items. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Although one or more of the embodiments disclosed herein may be described in detail with reference to a particular electronic device, the embodiments disclosed should not be interpreted or otherwise used as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application. For example, while the embodiments disclosed below may be focused on projecting images on a screen, other embodiments are possible that do not utilize a screen, such as holographic projection equipment. Accordingly, the discussion of any embodiment is meant only to be exemplary and is not intended to suggest that the scope of the disclosure, including the claims, is limited to these embodiments. 
       FIG. 1  illustrates a display system  100  that may include a projector  105  capable of emanating a combined beam  107  of coherent and incoherent light onto a screen  110 . 
     In some embodiments, the projector  105  and the screen  110  may be secured in a single location. For example, as shown in  FIG. 1 , the projector  105  and the screen  110  may be secured to the roof. Alternatively, in other embodiments (not specifically shown), the projector  105  may be part of a portable display system such that both the projector  105  and the screen  110  may be relocated if desired. Furthermore, while some of the embodiments discussed herein may employ a screen  110 , it should be appreciated that the screen&#39;s  110  use is optional and that the projector  105  may be situated to project the combined beam  107  onto any surface, whether flat or curved. Also, while the screen  110  depicted herein is shown as forward projecting, the screen  110  may be translucent and allow for rear projection in other embodiments. In a rear projection system, the screen  110  may be made of plastic or glass, such as in a rear projection television. In still other embodiments, the screen  110  may be omitted altogether and the combined beam  107  may be projected onto any surface, such as a wall, or such as air in the case of holographic systems. 
     As shown in  FIG. 1 , the projector  105  may couple to a video source  115  that is capable of generating image signals according to a variety of standards, both moving (e.g., ATSC, DVB, NTSC, PAL, SECAM, MPEG-4, etc.) and stationary (e.g., JPEG, TIFF, PNG, GIF, etc.), and then providing multiple component video signals associated with these image signals to the projector  105 . The component video signals may be a plurality of components of any desirable color space, such as red, green, blue (RGB), luminance, luminance minus red, and luminance minus blue (Y, Pr, Pb), cyan, magenta, yellow, and black (CMYK), CIELAB and/or CIEXYZ, and so on. 
     Depending upon the chosen embodiment, the video source  115  and/or display system  100  may take on a variety of different forms. For example, as shown in  FIG. 1 , the video source  115  may be a separate computer and the display system  100  and the video source powered from a separate source, such as an A/C wall outlet. However, in other embodiments, the projector  105  and the video source  115  may be integrated together in a single housing and operates off of a portable battery. For example,  FIG. 2  illustrates one embodiment where the video source  115  and projector  105  are integrated within a laptop computer  200 . Since the projector  105  is capable of providing a combined beam  107  at reduced power levels as compared to conventional coherent beam systems, such an embodiment may be desirable in a laptop computer  200  being powered from a battery, such as is in the commonly owned U.S. patent application Ser. Nos. 12/238,633 and 12/238,564, which are incorporated herein by reference as if fully set forth below. Other portable embodiments are also possible. For example, the video system  115  and the projector  105  also may be incorporated into a portable phone or other handheld device. 
     In still other embodiments, such as the embodiment shown in  FIG. 3 , the video source  115  may be a television signal receiver and the projector  105  may be used in a rear projection television  300 . As will be described in greater detail below, display systems, such as the television  300 , which operate the incoherent and coherent light sources in concert to render images with the combined beam  107  may be smaller and less bulky than televisions  300  that are based solely on coherent light sources because of the reduced need for power management circuitry. 
     Regardless of the particular implementation of the video source  115 , during operation, the video source  115  may provide one or more of the component video signals (e.g., one or more of the RGB signals) as video data to a network of components within the projector  105 .  FIG. 4  illustrates one embodiment showing a set of internal components  400 . The set of internal components  400  may exist within a common housing (as indicated by the dashed line in  FIG. 4 ), or alternatively, one or more of the components within the set of internal components  400  may exist in the housing of another device, such as the video source  115 . 
     As shown, the network  400  may include a microprocessor  402  coupled to the video source  115 . The microprocessor  402  may further couple to an incoherent light source  405  and a coherent light source  410 . When connected together in this manner, the microprocessor  402  may receive video data from the video source  115 , and convert this video data to a format that is suitable for display by the incoherent and coherent light sources  405  and  410 . 
     In some embodiments, images may be rendered on the screen  110  by driving the incoherent and coherent light sources  405  and  410  on a successive line-by-line basis.  FIG. 5  illustrates a signal  429  that may be used by the microprocessor  402  driving the incoherent and coherent light sources  405  and  410  when rendering a line  430  of the image on the screen  110 . As shown, the signal driving the incoherent and coherent light sources  405  and  410  may include a synchronization pulse  440  corresponding to the beginning of a scan line. For purposes of discussion, the synchronization pulse  440  is discussed in the context of beginning each image scan line  430  on the left side of the screen  110 , although it could begin at the right, top or bottom of the screen  110  instead. As the line  430  is scanned across to render the image, it may output different regions, such as the transition regions  450 ,  455 , and  460  of the sail in the image where the color content of the image may change between the transition regions  450 ,  455 , and  460 . In this example, the regions  450  and  460  may correspond to a white region of the image, while the region  455  may correspond to a colored region of the image, such as red, blue or black. The signal  429  includes portions  450 ,  455 , and  460  that correspond to these changes in color content respectively. As shown, during the white regions  450  and  460  the signal  429  may be high, thereby emanating white light from the incoherent and coherent light sources  405  and  410  onto the screen  110 , whereas during the colored region  455  the signal  429  may be lower than the regions  450  and  460 , thereby emitting less light from the incoherent and coherent light sources  405  and  410 , which may result in colored regions on the screen  110 , such as red, blue, or black. In some embodiments, the incoherent and coherent light sources  405  and  410  may be driven by different portions of the video signals, or different axes of a color space, to render different portions of the image. For example, the incoherent light source  405  may be driven by the luminance portion of the video signal while the coherent light source  410  may be driven by the chrominance portion of the video signal. 
     Referring back to  FIG. 4 , the incoherent and coherent light sources  405 ,  410  may be optically coupled to a network of optical elements  412  capable of modifying and/or combining incoming light from the incoherent and coherent light sources  405  and  410 . For example, in some embodiments, the network  412  may include digital mirror devices and/or lenses, servos, filters, modulators, to name but a few. During operation, the network  412  may optically combine and condition the light emanating from the incoherent and coherent light sources  405  and  410  and convey the combined coherent and incoherent light to the screen  110 . 
     The set of internal components  400  may include a temperature monitoring circuit  415  that is under control of the microprocessor  402  and able to track changes in one or more of the set of internal components  400  over time. In some embodiments the temperature monitoring circuit  415  may be one or more silicon based diodes (not shown), which may have a temperature coefficient of approximately negative two millivolts per degree Celsius. Depending upon the embodiment, these diodes may be located adjacent to one or more elements within the set of internal components  400 . As the temperature of the temperature monitoring circuit  415  increases, the voltage across these diodes may decrease. Similarly, as the temperature of the temperature monitoring circuit  415  decreases, the voltage across these diodes may increase. 
     The microprocessor  402  may monitor this changing voltage and compare it to a desired operating temperature for the various elements in the set of internal components  400  and adjust the temperature of the set of internal components via one or more thermal management devices. For example,  FIG. 4  illustrates a fan  420  that may cool the incoherent and coherent light sources  405  and  410  under the control of the microprocessor  402 . In other embodiments, the thermal management devices also may include a passive heat sink or an active Pelletier cooler thermally coupled to the incoherent and coherent light sources  405  and  410 . As will be described in greater detail below, because the projector  105  may utilize both incoherent and coherent light sources  405  and  410 , the overall amount of power dissipated by the projector  105  may be less than it otherwise would be if the projector  105  used solely coherent light sources. Accordingly, the need for multiple thermal management devices, such as both a fan and a Pelletier cooler, may be reduced, making the projector  105  more cost efficient and/or consume less space than if the projector  105  utilized solely coherent light sources. 
     As mentioned previously, incoherent light sources emit light waves that have multiple wavelengths of light, whereas coherent light sources generally are more precise and emit light waves that have a single wavelength of light. For example, an incoherent light source may be implemented with one or more white incandescent bulbs that emanate light with multiple different wavelengths simultaneously. In some embodiments, the incoherent light source may be an incandescent bulb of a particular color where the glass portion of the bulb acts as a filter to the emanating light waves and filters out all but a range of desired wavelengths. For example, as shown in  FIG. 4 , the light source  405  may include three separate incandescent bulbs  406 ,  407 , and  408  configured as red, green, and blue light sources, respectively, such that the light emanating from the bulbs  406 ,  407 , and  408  is in the range of wavelengths associated with red, green, and blue light. In other words, the bulb  406  may be associated with a red wavelength of about 650 nanometers as well as a range of about +/−10% about this wavelength. Similarly, the bulb  407  may be associated with a blue wavelength of about 475 nanometers as well as a range of wavelengths of about +/−10% of this wavelength. Lastly, the bulb  408  may be associated with a green wavelength of about 510 nanometers as well as a range of wavelengths of about +/−10% of this wavelength. 
     Other embodiments may implement the incoherent light sources  406 ,  407 , and  408  using individual incoherent light sources that emanate a more narrow range of wavelengths, such as by using an LED of a particular color. For example, when implementing the incoherent light source  406  using a red LED having the same 650 nanometer red wavelength noted above for the bulb embodiment, the LED based incoherent source  406  may have a range of wavelengths that is much more narrow than the +/−10% noted above. For example, the range of wavelengths emitted by a sample LED may be about +/−1% of the 650 nanometer wavelength 
     While the incoherent light source  405  may emanate multiple different wavelengths within a range of wavelengths, the coherent light source  410  may emanate single wavelengths of light, or in some embodiments, a much more narrow range of wavelengths than the incoherent light source  405 . For example, the coherent light source  410  may be implemented as one or more laser-based light sources that are tuned to emanate a single wavelength of light or multiple wavelengths. In this manner, the coherent light source  410  may include lasers  426 ,  427 , and  428  associated with the primary colors red, green, and blue respectively, where the wavelengths of the lasers are chosen such that they substantially match the desired wavelengths of the incoherent sources. Thus, if the incoherent red light source  406  is chosen with a 650 nanometer wavelength with a range of wavelengths of +/−10% around the 650 nanometer wavelength, then the laser  426  may be chosen such that it emanates a single wavelength of light at about 650 nanometers. Similarly, the lasers  427  and  428  may be chosen to emanate single wavelengths of blue and green light corresponding to the incoherent light sources  407  and  408 , or single wavelengths of about 475 and 510 nanometers, respectively. 
     It should be appreciated that although this disclosure may discuss the incoherent light source  405  and the coherent light source  410  as comprising multiple individual light sources, either one or both of the incoherent and coherent light sources  405  and  410  may be implemented as a single light source and such single source may operate in concert with one another. For example, instead of implementing the incoherent light source  405  with three separate light sources  406 ,  407  and  408  as shown in  FIG. 4 , the incoherent light source  405  may be implemented as a single incoherent light source that operates in concert with one or more of the coherent light sources  426 ,  427 , and/or  428 . Similarly, instead of implementing the coherent light source  410  with three separate light sources  426 ,  427  and  429 , the coherent light source  410  may be implemented as a single coherent light source that operates in concert with one or more of the incoherent light sources  406 ,  407 , and/or  408 . 
     During operation, the microprocessor  402  may receive video data from the video source  115  and drive video signals to the incoherent light source  405  while concurrently driving video signals to the coherent light source  410 . In other words, each of the individual incoherent light sources  406 ,  407 , and  408  may operate in concert with each of the individual coherent light sources  426 ,  427 , and  428 . 
       FIG. 6A  illustrates an example of the combined intensity of the incoherent light sources  406 ,  407 , and  408  in concert with the coherent light sources  426 ,  427 , and  428 . Referring to  FIG. 6A , the coincident horizontal position of the combined light sources  405  and  410  is illustrated on the abscissa axis and the overall intensity of the combined light sources  405  and  410  is illustrated on the ordinate axis. The intensity representation of the combined light sources  405  and  410  may represent any of the individual incoherent and coherent light sources  405  and  410  operating in concert with each other. For example, the overall intensity shown in  FIG. 6A  may represent the incoherent red light source  406  shown in  FIG. 4  operating in concert with the coherent red light source  426  shown in  FIG. 4 . FIGS.  6 B and  6 C illustrate alternative arrangements of operating the individual incoherent and coherent light sources  405  and  410  in concert with each other. Referring to the example shown in  FIG. 6B , this representation illustrates a baseline chrominance portion of the image on the coherent light source  410  while the incoherent light source  405  includes a modulated version of the chrominance in combination with the luminance portion of the image. Referring to the example shown in  FIG. 6C , this representation illustrates a modulated chrominance portion of the image on the coherent light source  410  where this modulated portion of complements the modulated version of the chrominance and luminance portions of the image as rendered by the incoherent light source  405 . Although  FIGS. 6A-C  illustrate various arrangements for operating the incoherent and coherent light sources  405  and  410  to display an image, the methods shown in  FIGS. 6A-C  are for illustrative purposes, and the actual configurations may vary between embodiments. 
     The shaded area beneath the intensity curve shown in  FIG. 6  represents the incoherent light source  405 . As can be appreciated from inspection of  FIG. 6 , a majority of the overall intensity of the light rendered on the screen  110  may be from the incoherent light source  405 , and as shown by the serrated line in  FIG. 6 , the coherent light source  410  may be superimposed on the light from the incoherent light source  405  in order to fine tune the intensity of the image rendered on the screen  110 . Coherent light sources generally are able to render images with greater detail than the incoherent light sources at the expense of operating at higher power levels than the incoherent light sources. Thus, the incoherent light source  405  may operate to establish a baseline intensity for the image. This baseline intensity may consume less power as compared to establishing this intensity level with the coherent light source  410  alone. However, since this baseline intensity is established with the incoherent light source  405 , its precision may not be as fine as if the coherent light source  410  were used to render the image alone. Accordingly, the coherent light source  410  may be operated at a lower power and/or intensity level (shown in  FIG. 6  by the relatively small excursions of the serrated edges) and then superimposed on top of the baseline set by the incoherent light source  405  to improve the resolution of the image. 
       FIGS. 7A and 7B  illustrate a cross section of the screen  110  (shown in  FIG. 1 ) taken along the line AA′. As can be appreciated from inspection of  FIGS. 7A and 7B , a reduced speckling effect that may occur as a result of combining the incoherent and coherent light sources  405  and  410 . The cross section of the screen  110  shown in  FIG. 7A  illustrates the situation where only the red (R), green (G), and blue (B) coherent light sources  426 ,  427 , and  428  are applied to the screen  110 . Because the screen  110  contains surface imperfections (shown in  FIG. 7A  as a rough surface and specifically the wavy line), the collimated light emanating from the coherent light sources  426 ,  427 , and  428  may be reflected off the surface imperfections and result in speckling or visual imperfections in the projected image. The cross section of the screen  110  shown in  FIG. 7B  illustrates the situation where the R, G, and B, coherent light sources  426 ,  427 , and  428  are applied to the screen  110  in conjunction with the R′, G′, and B′ incoherent light sources  406 ,  407 , and  408 . This arrangement may reduce the overall speckling of the image by presenting the observer with a dithered version of each of the light sources—i.e., the average of R and R′, G and G′, and B and B′ respectively. Thus, in addition to reducing the power level by operating the incoherent and coherent light sources  405  and  410  in concert with each other, speckling may be reduced by operating the coherent light source  410  in concert with the incoherent light source  405 . 
     Because the images on the screen  110  are a combination of the incoherent and coherent light sources  405  and  410 , in some embodiments, the microprocessor  402  may be used to calibrate the contribution of the coherent light source  410  so that this calibration can be used later during operation.  FIG. 8  illustrates operations  800  for calibrating the coherent light source  410 . In operation  805 , the microprocessor  402  may receive video data from the video source  115 . The microprocessor  402  may process this video data and determine the baseline level for the incoherent light source  405  (e.g., the baseline shown in  FIG. 5 ). The incoherent light source  405  may be set according to this baseline level in operation  810 . 
     Referring to  FIG. 4  in conjunction with  FIG. 8 , a light sensor  815  (shown in  FIG. 4 ) may sample the intensity of the image being projected onto the screen  110 . In some embodiments, this sampling may occur at various locations on the screen  110 . This sampling is illustrated in  FIG. 8  as operation  820 . During operation  825 , the sampled intensity may be compared to the desired baseline set by the microprocessor  402 . Initially, the intensity of the coherent light source  410  is zero and thus control may flow to operation  830  where the coherent light source  410  may be adjusted. After the adjustment operation  830 , control may flow back to operation  825  to determine if the adjustment made during operation  830  was adequate to achieve the desired intensity level. 
     If operation  825  determines that the desired intensity level of the coherent light source  410  was achieved during the adjustment of operation  830 , then control may flow to operation  835 , where the value of the intensity may be saved by the microprocessor  402  as a calibration point for later use during operation, and control subsequently may flow back to operation  810  to set the incoherent light source  405  to the next intensity value. 
     On the other hand, if operation  825  determines that the desired intensity level of the coherent light source  410  was not achieved during the adjustment operation  830 , then control may flow back to operation  830  for another adjustment. This back-and-forth between operations  825  and  830  may continue until the desired intensity for the coherent light source  410  is achieved, then control may flow to operations  825  and  810  to save this intensity level of the coherent light source  410  as a calibration point and control may subsequently flow back to operation  810  to set incoherent light source  405  to the next intensity value.

Metadata:
Filing Date: 20090930
Publication Date: 20130806
Grant Date: 20130806
Priority Date: 20090930
Inventors: BILBREY BRETT
Assignee: APPLE INC
CPC Classifications: [{"code": "G03B21/00", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N5/74", "inventive": true, "first": false, "tree": "[]"}, {"code": "H04N5/74", "inventive": true, "first": true, "tree": "[]"}, {"code": "H04N5/74", "inventive": true, "first": true, "tree": "[]"}]
Family ID: 42985207