Patent Application
20080024401
The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions should be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
The present invention will now be described with reference to the attached figures. Various structures, systems and devices are schematically depicted in the drawings for purposes of explanation only and so as to not obscure the present invention with details that are well known to those skilled in the art. Nevertheless, the attached drawings are included to describe and explain illustrative examples of the present invention. The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended to be implied by consistent usage of the term or phrase herein. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
One or more pixels 230(1-2) are deployed proximate the surface 210 of the wedge-shaped waveguide 205. Hereinafter, the index “230” will be used to refer to the pixels 230 collectively and the indices (1-2) will be used to refer to individual pixels, e.g. the pixel 230(1), or to various subsets of the pixels 230. This convention will also be used to indicate other components that may be referred to collectively, individually, or in subsets. In the illustrated embodiment, the pixels 230 are depicted as being deployed a small distance away from the surface 210. However, persons of ordinary skill in the art should appreciate that this distance is a matter of design choice and not material to the present invention. For example, the pixels 230 may be deployed substantially on or adjacent to the surface 210. Alternatively, the pixels 230 may be separated from the surface 210 by one or more layers of material and/or empty space. Furthermore, the number of pixels 230 is also a matter of design choice.
As will be discussed in detail below, the pixels 230 may be optically driven by incident light in a selected frequency band, such as blue light and/or ultraviolet light, and produce light of a selected color in response to the incident light. For example, the pixels 230 may down-convert ultraviolet light or blue light and convert at least a portion of the energy provided by the ultraviolet light into light that may be radiated in a red, blue, or green frequency band. Although the present invention will be discussed in terms of the pixels 230, persons of ordinary skill in the art having benefit of the present disclosure should appreciate that other devices, such as quantum dots, may be optically driven by the incident light to produce light of a selected color in response to the incident light.
A first light ray 235 may be injected into the wedge-shaped waveguide 205 at a first injection angle 240 relative to the injection surface 220. The first light ray 235 propagates through the wedge-shaped waveguide 205 until it reaches the surface 210 of the wedge-shaped waveguide 205. The injection angle 240 is chosen so that the first light ray 235 impinges on the surface 210 at an angle 245 relative to the normal 250 that is greater than the angle required for total internal reflection. Accordingly, the first light ray 235 is reflected internally and continues to propagate through the wedge-shaped waveguide 205. Persons of ordinary skill in the art having benefit of the present disclosure should appreciate that the term “total internal reflection” does not necessarily imply that all of the energy in the first light ray 235 is reflected internally. For example, evanescent waves may cause some energy to leak through the surface 210 when the first light ray 235 is reflected. For another example, the light ray 235 may not be perfectly collimated and so portions of the light ray 235 may intersect the surface 215 at angles smaller than the angle required for total internal reflection.
After reflection at the surface 210, the first light ray 235 may continue to propagate through the wedge-shaped waveguide 205 until it reaches the surface 215 where it may again be reflected internally. However, the relative inclination of the surfaces 210, 215 may cause the first light ray 235 to intersect the surface 215 at an angle 255 relative to a normal 260 to the surface 215 that is smaller than the angle 245. As the first light ray 235 continues to propagate down the wedge-shaped waveguide 205, the intersection angles between the first light ray 235 and the surfaces 210, 215 (relative to the normals 250, 260 to the surfaces 210, 215, respectively) may continue to decrease because of the relative inclination of the surfaces 210, 215.
The first light ray 235 emerges from the wedge-shaped waveguide 205 when the intersection angle relative to the normal 250 becomes smaller than the angle required for total internal reflection. In the illustrated embodiment, the first light ray 235 emerges from a point on the surface 210 that is proximate the pixel 230(1). The first light ray 235 may irradiate the pixel 230(1), which may then emit light 265 in response to irradiation by the first light ray 235. For example, the pixel 230(1) may convert a portion of the energy provided by the first light ray 235 into light 265 within a selected range of wavelengths, e.g., a wavelength range corresponding to a selected color, such as red, green, or blue. In one embodiment, the wavelength range of the light 265 substantially corresponds to the wavelength range of the first light ray 235, although the wavelength ranges of the light 235, 265 may not exactly correspond to each other. Alternatively, a characteristic wavelength within the wavelength range of the light 265 may be substantially longer than a characteristic wavelength within the wavelength range of the first light ray 235, i.e., the pixel 230(1) may downconvert a portion of the energy in the first light ray 235 to form the light 265.
Accordingly, by providing the first light ray 235 at the appropriate injection angle 240, the pixel 230(1) may be selected and induced to radiate, e.g. the pixel 230(1) may be optically addressed and driven by providing the first light ray 235 to the wedge-shaped waveguide 205 at the appropriate injection angle 240. In one embodiment, the intensity of the light 265 produced by the pixel 230(1) may be proportional to the intensity of the first light ray 235. Alternatively, the intensity of the light 265 produced by the pixel 230(1) may be related to the intensity of the first light ray 235 in some other manner, e.g., there may be a nonlinear relation between the intensity of the light 265 produced by the pixel 230(1) and the intensity of the first light ray 235.
In the illustrated embodiment, a second light ray 270 may be injected into the wedge-shaped waveguide 205 at a second injection angle 275. When the second injection angle 275 is smaller than the first injection angle 240, as shown in
The pixel 230(2) may then emit light 280 in response to irradiation by the second light ray 270. For example, the pixel 230(2) may convert a portion of the energy provided by the second light ray 270 into light 280 having a selected range of wavelengths, e.g., a range of wavelengths corresponding to a selected color, such as red, green, or blue, as discussed in detail above. Persons of ordinary skill in the art having benefit of the present disclosure should appreciate that the range of wavelengths (and/or the color) of the light 265, 280 provided by the pixels 230(1-2), respectively, may be the same (e.g., the flat-panel video display 200 may be monochromatic) or different (e.g., the flat panel video display 200 may be color).
The input image 300 includes two filled-in circles 310. A light ray associated with the filled-in circle 310(1) propagates through a wedge-shaped waveguide (not shown in
The light rays 420 are provided to the wedge-shaped waveguide 415 at a corresponding plurality of injection angles and/or injection points so that each light ray 420 may address and/or drive one or more pixels 425. In response to irradiation by one or more light rays 420, one or more of the pixels 425 may radiate light 430 to form a displayed image 435 that corresponds to the input image 410. In the illustrated embodiment, the pixels 425 (and the displayed image 435) are monochromatic. However, persons of ordinary skill in the art having benefit of the present disclosure should appreciate that, in alternative embodiments, the pixels 425 may be capable of producing more than one color of light. For example, the pixels 425 may be capable of producing red, green, and/or blue light. Accordingly, a color displayed image 435, which may or may not correspond to a color input image 410, may be produced by providing the light rays 420 at the appropriate injection angles, injection points, and/or intensities.
Optically addressing and driving pixels as described above may have a number of advantages over conventional practice. For example, optical addressing removes the need to electrically address each pixel as is done in liquid crystal displays (LCDs) and standard cathode ray tube (CRT) displays, which may reduce the cost of building and/or operating displays that implement optical addressing of pixels. Optical addressing and driving may also reduce chromatic dispersion, relative to conventional wedge displays, and reduce viewing angle dependence relative to conventional wedge displays and LCD displays. Displays that implement optical addressing and driving may also use a single color driver. In contrast, high end digital light processing (DLP) devices often use three driver chips, one for each of the three needed color channels.
The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.
| Number | Date | Country | |
|---|---|---|---|
| 60820509 | Jul 2006 | US |
