The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:
Referring initially to
In
The light source assembly 12 generates a light 24 for the projection system 10. As an overview, in certain embodiments, the light source assembly 12 generates a homogenized, incoherent bright white light 24 that includes blue light, green light and red light. As a result thereof, in certain embodiments, one or more components, such as a color wheel is not required for the DMD system. Further, in one embodiment, multiple light beams are multiplexed in a light pipe. With this design, the light source assembly 12 can be controlled to generate an output beam having any desired color, including red, blue, green, or white.
Moreover, in certain embodiments, the light source assembly 12 can be designed to efficiently generate the light 24 with relatively low power. This reduces the amount of heat generated by the light source assembly 12 and improves the performance of the precision apparatus 10. Additionally, the light source assembly 12 has a relatively long operational lifespan, has good power stability, and is relatively small in size.
The mirror 14 reflects the light 24 exiting from the light source assembly 12 and directs the light 24 at the imager 16.
The imager 16 creates the image 22. In one embodiment, the imager 16 is a digital light processing chip that includes anywhere from approximately 800 to more than 1 million tiny mirrors that are individually controlled to generate the image 22. Alternatively, for example, the imager 22 can be a LCD imager or a LCOS imager.
The lens 18 collects the image 22 from the imager 16 and focuses the image 22 on the screen 20. The screen 20 displays the image 22.
The number and design of the light sources 226 can be varied pursuant to the teachings provided herein. In one embodiment, the light source assembly 212 includes three separate light sources 226, namely a blue light source 234 (illustrated as a box) that generates blue light 234A (illustrated as an arrow), a green light source 236 (illustrated as a box) that generates green light 236A (illustrated as an arrow), and a red light source 238 (illustrated as a box) that generates red light 238A (illustrated as an arrow). The blue light 234A has a wavelength of between approximately 450-490 nm, the green light 236A has a wavelength of between approximately 490-570 nm, and the red light 238A has a wavelength of between approximately 630-700 nm. Alternatively, the light source assembly 212 could be designed with greater than or fewer than three light sources 236.
It should be noted that the blue light source 234, the green light source 236, and/or the red light source 238 can be referred to herein as the first light source, the second light source, or the third light source. Further, the blue light 234A, the green light 236A, and/or the red light 238A can be referred to herein as the first light, the second light, or the third light.
In one embodiment, each of the light sources 226 is a light emitting diode (“LED”). In this example, the blue light source 234 is a blue LED, the green light source 236 is a green LED, and the red light source 238 is a red LED. In one non-exclusive embodiment, the blue light source 234 has an output of between approximately 100 to 200 lumen, the green light source 236 has an output of between approximately 900 to 1100 lumen, and the red light source 238 has an output of between approximately 300 to 500 lumen. Alternatively, each of the light sources 234, 236, 238 can be designed to have an output that is greater or lesser than the amounts described above.
In one embodiment, each of light sources 234, 236, 238 is turned on and off is sequence. As a result thereof, a color wheel (not shown) may not be necessary for a DMD system. This allows for a smaller form factor for the DMD system and can reduce the cost for assembly of the DMD system. Moreover, the LED's have a relatively long operational lifespan. Alternatively, the light sources 234, 236, 238 can be maintained on and a color wheel can be utilized. Further, the light sources 234, 236, 238 can be controlled to generate an output light 224 having any desired color, including red, blue, green, or white.
The optical pipe 228 captures the lights 234A, 236A, 238A and homogenizes the lights 234A, 236A, 238A so that the output light 224 exiting the light source assembly 212 is uniform, consistent, and has the desired aspect ratio. Optical pipes are also sometimes referred to as light tunnels or tunnel integrators. The design of the optical pipe 228 can be varied pursuant to the teachings provided herein.
Further, in this embodiment, the pipe passageway 228A (i) is substantially linear and includes a substantially linear passageway axis 228L, (ii) does not include any bends, and (iii) the light 234A, 236A, 238A from the light sources 234, 236, 238 travel down the same pipe passageway 228A. As a result of this design, in certain embodiments, the profile of the light source assembly 212 can be relatively small. Alternatively, pipe passageway 228A can include one or more bends. For example, the pipe passageway 228A can include one or more 90 degree bends.
In one embodiment, the optical pipe 228 includes a generally rectangular tube shaped pipe body 228B and a wall coating 228C that define the generally rectangular shaped pipe passageway 228A. The pipe body 228B can include four walls 228D, with each of the walls 228D having an interior wall surface and an exterior wall surface. The four walls 228D can be referred to as a top wall, a bottom wall, a left wall, and a right wall for convenience. Alternatively, for example, the pipe body 228B can have another configuration, such as a circular shaped tube, an octagon shaped tube, or a triangular shaped tube for example.
In one embodiment, the interior wall surfaces are coated with the wall coating 228C. For example, the wall coating 228C can have a relatively high reflectivity for the visible wavelength range (approximately 400-750 nm). With this design, the wall coating 228C inhibits the light 224 from exiting the pipe passageway 228A and homogenizes the light 224. Suitable wall coatings 228C can include dielectric materials and/or metal (silver or aluminum) material.
The wall coating 228C may have to be applied with multiple coating layers, and can be deposited using a number of different methods including physical vapor deposition such as ion beam sputtering, magnetron sputtering, and ion assisted evaporation. One method for depositing a coating is disclosed in U.S. Pat. No. 6,736,943, the contents of which are incorporated herein by reference.
Moreover, in this embodiment, the optical pipe 228 includes (i) a leading edge 228E, (ii) an opposed trailing edge 228F (sometimes referred to as the “output end”) that faces the mirror 14 (illustrated in
The red light 238A is directed into the optical pipe 228 at the red region 228G, the green light 236A is directed into the optical pipe 228 at the green region 228H, and the blue light beam 234A is directed into the optical pipe 228 at the blue region 228I. In
The homogenizing region 228J homogenizes the light 234A, 236A, 238A that travel down the pipe passageway 228A. In
In
Moreover, in
The director assembly 230 allows the desired light to enter the pipe passageway 228A and directs the desired light down the pipe passageway 228A. The design of the director assembly 230 can vary pursuant to the teachings provided herein. In
It should be noted that the red pass filter 240, the green pass filter 244, and/or the blue pass filter 248 can be referred to as a first pass filter, a second pass filter, or a third pass filter. These pass filters 240, 244, 248 keep light that has entered the pipe passageway 228A in the pipe passageway 228A to enhance the efficiency of the assembly. It should also be noted that the green Dichroic filter 246 or the blue Dichroic filter 250 can be referred to as a first Dichroic filter or a second Dichroic filter.
The red pass filter 240 is positioned between the red light source 238 and the pipe passageway 228A, allows red light 238A from the red light source 238 to enter the pipe passageway 228A, and inhibits red light 238A in the pipe passageway 228A from exiting via the red pass filter 240. In one embodiment, the red pass filter 240 is capable of (i) transmitting a high percentage of red light that is within a red predetermined angle of incidence range, (ii) reflecting a high percentage red light that is outside the red predetermined angle of incidence range, (iii) reflecting a high percentage of blue light, and (iv) reflecting a high percentage of green light. In alternative, non-exclusive embodiments, the red predetermined angle of incidence range is between approximately 0 to 50; 0 to 45; 0 to 30; 0 to 20; 0 to 10; or 0 to 5 degrees.
Further, in alternative, non-exclusive embodiments, the phrase “transmitting a high percentage” shall mean an average transmittance of greater than approximately 85, 90, 95, 96, 97, 98, or 99. Moreover, in alternative, non-exclusive embodiments, phrase “reflecting a high percentage” shall mean an average reflection of greater than approximately 85, 90, 95, 96, 97, 98, or 99.
In
The end reflector 242 reflects the red light 238A and directs the red light 238A along the pipe passageway 228A. In
The green pass filter 244 is positioned between the green light source 236 and the pipe passageway 228A, allows green light 236A from the green light source 236 to enter the pipe passageway 228A, and inhibits green light 236A and red light 238A in the pipe passageway 228A from exiting via the green pass filter 244. In one embodiment, the green pass filter 244 is capable of (i) transmitting a high percentage of green light that is within a green predetermined angle of incidence range, (ii) reflecting a high percentage green light that is outside the green predetermined angle of incidence range, (iii) reflecting a high percentage of blue light, and (iv) reflecting a high percentage of red light. In alternative, non-exclusive embodiments, the green predetermined angle of incidence range is between approximately 0 to 50; 0 to 45; 0 to 30; 0 to 20; 0 to 10; or 0 to 5 degrees.
In
The green dichroic filter 246 reflects the green light 236A and directs the green light 236A along the pipe passageway 228A while allowing red light 238A to pass therethrough. In
The blue pass filter 248 is positioned between the blue light source 234 and the pipe passageway 228A, allows blue light 234A from the blue light source 234 to enter the pipe passageway 228A, and inhibits blue light 234A, green light 236A, and red light 238A in the pipe passageway 228A from exiting via the blue pass filter 248. In one embodiment, the blue pass filter 248 is capable of (i) transmitting a high percentage of blue light that is within a blue predetermined angle of incidence range, (ii) reflecting a high percentage blue light that is outside the blue predetermined angle of incidence range, (iii) reflecting a high percentage of green light, and (iv) reflecting a high percentage of red light. In alternative, non-exclusive embodiments, the blue predetermined angle of incidence range is between approximately 0 to 50; 0 to 45; 0 to 30; 0 to 20; 0 to 10; or 0 to 5 degrees.
In
The blue dichroic filter 250 reflects the blue light 234A and directs the blue light 234A along the pipe passageway 228A while allowing red light 238A and green light 236A to pass therethrough. In
Further, in one embodiment, the green dichroic filter 246 and the blue dichroic filter 250 are arranged in series along the linear passageway axis 228L. This can reduce the footprint of the light source assembly 212. Moreover, one or both of the dichroic filters 246, 250 can be an interference filter and can have a high effective index (n greater than approximately 1.75) to provide improved response for the tilted coatings. As described above, each dichroic filter 246, 250 can be a plate type filter. In one embodiment, a plate type filter is an interference filter deposited onto a parallel plate substrate (e.g. glass). The plate type dichroic filter may be designed to have a high effective refractive index to improve filter response when tilted at angles to incident light.
The design of each of the red pass filter 240, the end reflector 242, the green pass filter 244, the green Dichroic filter 246, the blue pass filter 248, and the blue Dichroic filter 250 can be varied pursuant to the teachings provided herein. In one embodiment, each of the components includes a substrate 252 and coating 254 that coats the substrate 252. As an example, the substrate 252 can be a piece of glass or other transparent material. The coating 254 for each of the components is uniquely designed to achieve the desired level of reflectance for each of these components. Suitable coatings 254 can include dielectric materials and/or metal (silver or aluminum) material. The coatings 254 may have to be applied with multiple coating layers, and can be deposited using a number of different methods including physical vapor deposition such as ion beam sputtering, magnetron sputtering, and ion assisted evaporation. One method for depositing the coatings 254 is disclosed in U.S. Pat. No. 6,736,943.
In one embodiment, each of the pass filters 240, 244, 248 is built as an edge filter using thin film interference technology. The edge filter is designed to transmit at normal incidence (perpendicular to the filter) or near-normal incidence at the desired pass color (wavelength) while reflecting all other colors. Furthermore, the filter also reflects the desired color at non-normal angles. This is done using the angle shifting properties of thin films where at high angles, the edge, reflection bands and passbands of the filter shifts to shorter wavelengths. The shifting of the reflection bands provides the desired effect of having the same color which transmits at normal to be substantially reflected at non-normal wavelengths. Using these techniques, the pass filters 240, 244, 248 can also be designed to transmit a wavelength at normal (perpendicular to the filter), and reflect the wavelength at relatively high angles.
Furthermore, in
In one embodiment, the light sources 433 include a red LED, a magenta LED, a green LED, a cyan LED, and a blue LED. Alternatively, other colors can be utilized.
In one embodiment, moving from the leading edge 428E to the trailing edge (not shown in
Additionally, in this embodiment, the director assembly 530 does not include any pass filters. More specifically, in this embodiment, light that enters the solid light pipe continues to travel in the light pipe using total internal reflection. Alternatively, one or more pass filters can be used that function as an anti-reflection coating at normal and a reflector at high angles.
In
Each collimator 734B, 736B, 738B collimates the light from the respective light source 734, 736, 738 so that the light entering the pipe passageway 728A is largely collimated. The design of each collimator 734B, 736B, 738B can vary. In one embodiment, each of the collimators 734B, 736B, 738B is tapered light pipe collimator. Alternatively, one or more of the collimators 734B, 736B, 738B can be a lens type collimator or a total internal reflection type collimator.
Each heat sink 734C, 736C, 738C removes heat from the respective light source 734, 736, 738. The design of each heat sink 734C, 736C, 738C can vary. In one embodiment, the heat sink 734C, 736C, 738C can include a plurality of spaced apart fins.
Further, in the embodiment illustrated in
It should be noted that one or more of the collimators 734B, 736B, 738B and/or one or more of the heat sinks 734C, 736C, 738C can be incorporated into one or other embodiments described or illustrated herein.
While the particular apparatus 10 as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages herein before stated, it is to be understood that it is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended to the details of construction or design herein shown other than as described in the appended claims.
This application claims priority on U.S. Provisional Application Ser. No. 60/810,317 filed on Jun. 2, 2006 and entitled “LIGHT SOURCE ASSEMBLY WITH INTEGRATED OPTICAL PIPE”. The contents of U.S. Provisional Application Ser. No. 60/810,317 are incorporated herein by reference.
Number | Date | Country | |
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60810317 | Jun 2006 | US |