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US 6,856,464 B1Granted
Color splitting apparatus and method with unequal glass path lengths
AssigneeTexas Instruments Incorporated
InventorsFrank J. Poradish, Steven M. Penn
Life of this patent
Estimating the term…
Abstract
A three element prism system and method for splitting/combining three different colors of light arranged such that the size of a selected one of the color prism, such as for example, the red prism and, consequently the clear aperture, are increased without a corresponding increase in the size of the other prisms (e.g., the blue and green prisms). This is accomplished by adjusting the air gap A2 of the selected light path (e.g., red) so that the effective total selected light path T, which includes the selected light air gap A2 and the selected light glass path G2 is the same as the total path length T of both the other light paths (e.g., green and blue) comprised of air gap A1 plus glass path G1.
Claims29
A prism system for splitting/combining different colors of light comprising:
- a first prism element having a face for projecting and receiving a first color of light;
- a first surface supported substantially parallel and spaced to form an air gap having a length A1 from said face of said first prism;
- a first light path through said prism for said first color having a glass path length G1 through said prism system such that the total path length T for said first color is equal to the length of the air gap A1 plus the glass path length G1 (T=A1+G1);
- another prism element having a face for projecting and receiving another color of light;
- another surface supported substantially parallel and spaced to form an air gap having a length A2 from said face of said another prism element;
- and
- another path through said prism system for said another color having a glass path length G2 that is different from glass path length G1, glass path length G2 selected such that the total path length T for said another color is the same as the total path length T of said first color (A2+G2=T=A1+G1).
4 more elements
A three element prism system arranged for splitting/combining three different colors of light comprising:
- a first and second prism elements, each of said first and second elements having a face for projecting and receiving one of a first and second color of light respectively;
- first and second surfaces, each of said first and second surfaces supported substantially parallel and spaced to form an air gap having a length A1 from one of said faces of said first and second prism elements;
- first and second light paths through said arrangement of prism for said first and second colors respectively, both of said first and second paths having a glass path length G1 through said arrangement of prisms such that the total path length T of both said first and second colors is equal to the length of the air gap A1 plus the glass path length G1 (T=A1+G1);
- another prism element having a face for projecting and receiving a third color of light;
- another surface supported substantially parallel and spaced to form an air gap having a length A2 from said face of said another prism element;
- and
- another path through said prism arrangement for said third color having a glass path length G2 that is different from glass path length G1, glass path length G2 selected such that the total path length T for said third color is the same as the total path length T of said first and second colors (A2+G2=T=A1+G1).
4 more elements
A method of projecting different color images to a single display surface comprising the steps of:
- spacing a first image source having a first color to form a first selected air gap having a length A1 from a receiving face of a first element of a prism system;
- spacing another image source having another color to form a second selected air gap having a length A2 from the receiving face of another element of said prism system;
- transmitting light from said first image source along a first path within said prism system toward said display surface, said first path having a glass path length G1;
- transmitting light from said another image source along another path toward said display surface, said another path having a first portion in said first element of said prism system and another portion in said another element of said prism system, said another path having a glass path length G2, said glass path length G2 different than said glass path length G1;
- and
- adjusting said air gap length A2 such that A2 plus said glass path length G2 is equal to said air gap length A1 plus said glass path length G1.
3 more elements
A method of projecting different color images to a single display surface comprising the steps of:
- spacing a first image source having a first color and a second image source having a second color to form a first selected air gap having a length A1 from a receiving face of first and second elements respectively, of a three element prism system;
- spacing another image source having another color to form a second selected air gap having a length A2 from the receiving face of another element of said three element prism system;
- transmitting light from said first image source along a first path wholly within said first element of said prism system toward said display surface, said first path having a glass path length G1;
- transmitting light from said second source along a second path toward said display surface, said second path having a first portion in said first element of said prism system, a second portion in said second element of said prism system, and a third portion in said third element of said prism system, said second path having said glass path length G1;
- transmitting light from said another source along another path toward said display surface, said another path having a first portion in said first element of said prism system and another portion in said another element of said prism system, said another path having a glass path length G2, said glass path length G2 different than said glass path length G1;
- and
- adjusting said air gap length A2 such that A2 plus said glass path length G2 is equal to said air gap length A1 plus said glass path length G1.
4 more elements
Dependencies are inferred from the claim text.