Image projection system with a polarizing beam splitter
First Claim
1. An image projection system, comprising:
- a) a light source capable of producing a visible light beam;
b) a polarizing beam splitter, located near the light source in the light beam and oriented at an angle with respect to the light beam, the beam splitter comprising;
1) a first transparent substrate having a first surface located in the light beam with the light beam striking the first surface at an angle, and having a refractive index;
2) a second layer, separate from the first transparent substrate, having a refractive index; and
3) a generally parallel arrangement of thin, elongated, spaced-apart elements disposed between the first transparent substrate and the second layer, and forming a plurality of gaps between the elements, the gaps providing a refractive index less than the refractive index of the first transparent substrate or the second layer, the arrangement being configured and the elements being sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization oriented parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
c) a reflective array located near the polarizing beam splitter in either the reflected or transmitted beam, the array modulating the polarization of the beam by selectively altering the polarization of the beam to encode image information thereon and creating a modulated beam, the array being oriented to direct the modulated beam back towards the polarizing beam splitter;
d) the beam splitter further being located in the modulated beam and oriented at an angle with respect to the modulated beam, and the arrangement of elements of the beam splitter interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to the plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam, to separate out the unaltered polarization from the modulated beam;
e) a screen located in either the second reflected beam or the second transmitted beam for displaying the encoded image information.
1 Assignment
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Accused Products
Abstract
An image projection system has a wire grid polarizing beam splitter which functions as both the polarizer and the analyzer in the system. A light source produces a source light beam directed at the beam splitter which reflects one polarization and transmits the other. A liquid crystal array is disposed in either the reflected or transmitted beam. The array modulates the polarization of the beam, encoding image information thereon, and directs the modulated beam back to the beam splitter. The beam splitter again reflects one polarization and transmits the other so that the encoded image is either reflected or transmitted to a screen. The beam splitter can be an embedded wire grid polarizer with an array of parallel, elongated, spaced-apart elements sandwiched between first and second layers. The elements form a plurality of gaps between the elements which provide a refractive index less than the refractive index of the first or second layers.
35 Citations
74 Claims
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1. An image projection system, comprising:
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a) a light source capable of producing a visible light beam;
b) a polarizing beam splitter, located near the light source in the light beam and oriented at an angle with respect to the light beam, the beam splitter comprising;
1) a first transparent substrate having a first surface located in the light beam with the light beam striking the first surface at an angle, and having a refractive index;
2) a second layer, separate from the first transparent substrate, having a refractive index; and
3) a generally parallel arrangement of thin, elongated, spaced-apart elements disposed between the first transparent substrate and the second layer, and forming a plurality of gaps between the elements, the gaps providing a refractive index less than the refractive index of the first transparent substrate or the second layer, the arrangement being configured and the elements being sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization oriented parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
c) a reflective array located near the polarizing beam splitter in either the reflected or transmitted beam, the array modulating the polarization of the beam by selectively altering the polarization of the beam to encode image information thereon and creating a modulated beam, the array being oriented to direct the modulated beam back towards the polarizing beam splitter;
d) the beam splitter further being located in the modulated beam and oriented at an angle with respect to the modulated beam, and the arrangement of elements of the beam splitter interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to the plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam, to separate out the unaltered polarization from the modulated beam;
e) a screen located in either the second reflected beam or the second transmitted beam for displaying the encoded image information. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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37. A method for projecting an image, the method comprising:
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a) producing a source light beam having a wavelength in a range between approximately 0.4 to 0.7 microns using a light source;
b) substantially separating polarizations of the source light beam using a polarizing beam splitter disposed in the source light beam, the polarizing beam splitter including;
1) a first layer having a refractive index;
2) a second layer, separate from the first layer, having a refractive index;
3) a generally parallel arrangement of thin, elongated, spaced-apart elements, disposed between the first and second layers, configured and sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization orientation that lies in the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
4) a plurality of gaps, formed between the elements and the first and second layers, configured to provide a refractive index less than the refractive index of the first or second layers;
c) modulating either the transmitted or reflected beam and creating a modulated beam by selectively altering the polarization of the beam using an array disposed in either the transmitted or reflected beam;
d) substantially separating the polarizations of the modulated beam using the polarizing beam splitter disposed in the modulated beam, the elements interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization orientation that lies in the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam; and
e) displaying either the second transmitted beam or the second reflected beam on a screen.
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38. An image display system for producing a visible image, the system comprising:
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a) a light source configured to emit a source light beam having a wavelength in a range between approximately 0.4 to 0.7 microns;
b) a liquid crystal array positioned and oriented to receive and modulate at least a portion of the source light beam to create a modulated beam containing image information;
c) a screen positioned and oriented to receive and display at least a portion of the modulated beam; and
d) a polarizing beam splitter positioned and oriented to receive both the source light beam and the modulated beam, the polarizing beam splitter including;
1) a first layer having a refractive index;
2) a second layer, separate from the first layer, having a refractive index;
3) a generally parallel arrangement of thin, elongated, spaced-apart elements, disposed between the first and second layers, configured and sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization orientation that lies in the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam, and interacts with the electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the modulated light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization orientation that lies in the plane that includes at least one of the elements and the direction of the modulated light beam, defining a second reflected beam; and
4) a plurality of gaps, formed between the elements and the first and second layers, configured to provide a refractive index less than the refractive index of the first or second layers.
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63. An image projection system, comprising:
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a) a light source producing a visible light beam;
b) a polarizing beam splitter located near the light source in the light beam and oriented at an angle with respect to the light beam, the beam splitter comprising;
1) a first transparent substrate having a first surface located in the light beam with the light beam striking the first surface at an angle;
2) the first transparent substrate having a thickness less than approximately 5 millimeters; and
3) a generally parallel arrangement of thin, elongated, spaced-apart elements, disposed on the first transparent substrate, the arrangement being configured and the elements being sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization oriented parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
c) a reflective array located near the polarizing beam splitter in either the reflected or transmitted beam, the array modulating the polarization of the beam by selectively altering the polarization of the beam to encode image information thereon and creating a modulated beam, the array being oriented to direct the modulated beam back towards the polarizing beam splitter;
d) the beam splitter further being located in the modulated beam and oriented at an angle with respect to the modulated beam, and the arrangement of elements of the beam splitter interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to the plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam, to separate out the unaltered polarization from the modulated beam; and
e) a screen located in either the second reflected beam or the second transmitted beam for displaying the encoded image information. - View Dependent Claims (64, 65, 66, 68, 69, 70)
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67. An image projection system, comprising:
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a) a light source producing a visible light beam;
b) a polarizing beam splitter located near the light source in the light beam and oriented at an angle with respect to the light beam, the beam splitter comprising;
1) a first transparent substrate having a first surface located in the light beam with the light beam striking the first surface at an angle;
2) the first transparent substrate having a flatness less than approximately 3 standard wavelengths deviation per inch; and
3) a generally parallel arrangement of thin, elongated, spaced-apart elements, disposed on the first transparent substrate, the arrangement being configured and the elements being sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization oriented parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
c) a reflective array located near the polarizing beam splitter in either the reflected or transmitted beam, the array modulating the polarization of the beam by selectively altering the polarization of the beam to encode image information thereon and creating a modulated beam, the array being oriented to direct the modulated beam back towards the polarizing beam splitter;
d) the beam splitter further being located in the modulated beam and oriented at an angle with respect to the modulated beam, and the arrangement of elements of the beam splitter interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to the plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam, to separate out the unaltered polarization from the modulated beam; and
e) a screen located in either the second reflected beam or the second transmitted beam for displaying the encoded image information.
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71. An image projection system, comprising:
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a) a light source producing a visible light beam;
b) a polarizing beam splitter located near the light source in the light beam and oriented at an angle with respect to the light beam, the beam splitter comprising;
1) a first transparent substrate having a first surface located in the light beam with the light beam striking the first surface at an angle; and
2) a generally parallel arrangement of thin, elongated, spaced-apart elements, disposed on the first transparent substrate, the arrangement being configured and the elements being sized to interact with electromagnetic waves of the source light beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to a plane that includes at least one of the elements and the direction of the incident light beam, defining a transmitted beam, and (ii) reflect light from the elements which has a polarization oriented parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a reflected beam;
c) a reflective array located near the polarizing beam splitter in either the reflected or transmitted beam, the array modulating the polarization of the beam by selectively altering the polarization of the beam to encode image information thereon and creating a modulated beam, the array being oriented to direct the modulated beam back towards the polarizing beam splitter;
d) the beam splitter further being located in the modulated beam and oriented at an angle with respect to the modulated beam, and the arrangement of elements of the beam splitter interacting with electromagnetic waves of the modulated beam to generally (i) transmit light through the elements which has a polarization oriented perpendicular to the plane that includes at least one of the elements and the direction of the incident light beam, defining a second transmitted beam, and (ii) reflect light from the elements which has a polarization parallel with the plane that includes at least one of the elements and the direction of the incident light beam, defining a second reflected beam, to separate out the unaltered polarization from the modulated beam; and
e) a screen located in either the second reflected beam or the second transmitted beam for displaying the encoded image information; and
f) the first and second transmitted beams having a geometric distortion less than approximately 3 wavelengths deviation per inch. - View Dependent Claims (72, 73, 74)
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Specification