Efficient arc lamp illuminator for projection system
AssigneeKoninklijke Philips Electronics N.V.
InventorPeter J Janssen
Life of this patent
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Abstract
An arc lamp illuminator for a projection system includes one or more polarization conversion prisms to laterally spread the arc image. A pair or triplet of projection lenses can be used with mirrors and field lenses to direct the arc image along separate paths to separate polarization conversion prisms to further laterally spread the original arc image. A compact arrangement of the two-path embodiment is enabled by the use of a compound light guide including a pair of arc image-sized input ports, a pair of TIR prisms for directing the arc image along a common path, and a rectangular light guide for guiding the arc images to the polarization conversion system.
Claims8
An arc lamp illuminator for a projection system comprising:
- an arc lamp comprising an envelope enclosing an elongated arc having an axis lying in a lateral plane;
- at least one projection lens for projecting an image of the arc onto an image plane, the image plane oriented parallel to the arc image axis;
- at least one polarization conversion system comprising at least two compound prisms, each compound prism including an internal directional polarizer for splitting the projected arc image into primary and secondary arc images split laterally along the axis in the image plane to result in an elongated illumination beam which is elongated along the arc axis for a distance greater than the length of the original arc image, and for converting the primary and secondary arc images into polarized arc images having first and second polarization senses, respectively;
- and
- a rotator device for converting the polarization sense of either the primary or secondary arc image to correspond to the polarization sense of the other arc image.
A projection system comprising:
- a light modulator panel for modulating a light image in accordance with an electrical signal;
- a lens for projecting the modulated image onto a display screen;
- and
- an arc lamp illuminator for illuminating the light modulator panel, the illuminator comprising:
- an arc lamp comprising an envelope enclosing an elongated arc having an axis lying in a lateral plane;
- at least one projection lens for projecting an image of the arc onto an image plane, the image plane oriented parallel to the arc image axis;
- at least one polarization conversion system comprising at east two compound prisms, each compound prism including an internal directional polarizer for splitting the projected arc image into primary and secondary arc images split laterally along the axis in the image plane to result in an elongated illumination beam which is elongated along the arc axis for a distance greater than the length of the original arc image, and for converting the primary and secondary arc images into polarized arc images having first and second polarization senses, respectively;
- and
- a rotator device for converting the polarization sense of either the primary or secondary polarized arc image to correspond to the polarization sense of the other polarized arc image.
Dependencies are inferred from the claim text.