Polarization converting color combiner

An optical element, comprising:

• a first reflective polarizer disposed to intercept a first light beam and a second light beam at an angle of approximately 45 degrees;
• a second reflective polarizer disposed to intercept a second polarization state of the first and the second light beam reflected from the first reflective polarizer, at an angle of approximately 45 degrees;
• a reflector disposed so that a line normal to the reflector intercepts the second reflective polarizer at an angle of approximately 45 degrees;
• and
• a retarder disposed between the second reflective polarizer and the reflector,
• wherein the first and second reflective polarizers, the reflector, and the retarder are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and the second light beams, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a first reflective polarizer disposed to intercept the first light beam and the second light beam at an angle of approximately 45 degrees;
• a second reflective polarizer disposed to intercept a transmitted first and second light beams from the first reflective polarizer at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intercepts the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflector disposed so that a line normal to the second reflector intercepts the second reflective polarizer at an angle of approximately 45 degrees;
• a first and a second retarder disposed between the first and second color-selective dichroic filters, respectively, and the first reflective polarizer;
• a fourth, and a fifth retarder disposed between the first reflector and the first reflective polarizer, and the second reflector and the second reflective polarizer, respectively,
• wherein the first and second reflective polarizers, the first and second reflectors, and the retarders are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and second light beams, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a first reflective polarizer disposed to intercept the first light beam at an angle of approximately 45 degrees;
• a second reflective polarizer disposed to intercept the second light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intercepts the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflector disposed so that a line normal to the second reflector intercepts the second reflective polarizer at an angle of approximately 45 degrees;
• a first and a second retarder disposed between the first and second color-selective dichroic filters, respectively, and the first reflective polarizer;
• a fourth, and a fifth retarder disposed between the first reflector and the first reflective polarizer, and the second reflector and the second reflective polarizer, respectively,
• wherein the first and second reflective polarizers, the first and second reflectors, and the retarders are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and second light beams, respectively.

An optical element, comprising:

• an unpolarized light beam perpendicular to a first input surface;
• a first reflective polarizer disposed to intercept the unpolarized light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intercepts the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflective polarizer disposed at an angle of approximately 90 degrees to the first reflective polarizer on a side opposite the first reflector;
• a second and a third reflector disposed so that a line normal to each intercepts the second reflective polarizer at an angle of approximately 45 degrees;
• and
• a first, a second, and a third retarder disposed adjacent each of the first, second and third reflectors, respectively,
• wherein the first and second reflective polarizers and the retarders are disposed to convert a second polarization state of the unpolarized light beam into a first polarization state of the unpolarized light beam.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a first reflective polarizer disposed to intercept the first and the second light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intercepts the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflective polarizer disposed at an angle of approximately 90 degrees to the first reflective polarizer on a side opposite the first reflector;
• a second and a third reflector disposed so that a line normal to each intercepts the second reflective polarizer at an angle of approximately 45 degrees;
• and
• a first, a second, and a third retarder disposed adjacent each of the first, second and third reflectors, respectively,
• wherein the first and second reflective polarizers and the retarders are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and the second light beam, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a first reflective polarizer disposed to intercept the first light beam and the second light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intersects the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflective polarizer disposed to intercept a transmitted first and second light beam from the first reflective polarizer at an angle of approximately 45 degrees;
• a half-wave retarder disposed between the first reflective polarizer and the second reflective polarizer;
• a first and a second quarter-wave retarder disposed between the first and the second color-selective dichroic filters, respectively, and the first reflective polarizer;
• and
• a fourth quarter-wave retarder between the reflector and the first reflective polarizer,
• wherein the first and second reflective polarizers, the reflectors, and the retarders are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and the second light beams, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a first reflective polarizer disposed to intercept the first light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intersects the first reflective polarizer at an angle of approximately 45 degrees;
• a second reflective polarizer disposed to intercept the second light beam at an angle of approximately 45 degrees;
• a half-wave retarder disposed between the first reflective polarizer and the second reflective polarizer;
• a first and a second quarter-wave retarder disposed between the first and the second color-selective dichroic filters, respectively, and the first reflective polarizer;
• and
• a fourth quarter-wave retarder between the reflector and the first reflective polarizer,
• wherein the first and second reflective polarizers, the reflectors, and the retarders are disposed to convert a second polarization state of the first and the second light beam into a first polarization state of the first and the second light beams, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a reflective polarizer, disposed to intercept the first light beam and the second light beam at an angle of approximately 45 degrees;
• a first reflector disposed so that a line normal to the first reflector intercepts the reflective polarizer at an angle of approximately 45 degrees;
• and
• a retarder disposed between the reflector and the reflective polarizer,
• wherein the reflective polarizer, the first reflector, and the retarder are disposed to convert a second polarization state of the first and second light beam into a first polarization state of the first and second light beams, respectively.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a second color-selective dichroic filter having a second input surface, disposed to transmit a second light beam perpendicular to the second input surface;
• a reflective polarizer, disposed to intercept the first light beam and the second light beam at an angle of approximately 45 degrees;
• a first and a second retarder disposed between the first and the second color-selective dichroic filter and the reflective polarizer, respectively;
• a first reflector disposed so that a line normal to the first reflector intercepts the reflective polarizer at an angle of approximately 45 degrees;
• and
• a fourth retarder disposed between the reflective polarizer and the reflector,
• wherein the reflective polarizer, the reflector and the retarders are disposed to combine the first and the second light beams into a combined unpolarized light beam.

An optical element, comprising:

• a first color-selective dichroic filter having a first input surface, disposed to transmit a first light beam perpendicular to the first input surface;
• a reflective polarizer, disposed to intercept the first light beam at an angle of approximately 45 degrees;
• a second color-selective dichroic filter having a second input surface disposed adjacent to the reflective polarizer, and opposite the first color-selective dichroic filter, the second color-selective dichroic filter disposed to transmit a second light beam;
• a first retarder disposed between the first color-selective dichroic filter and the reflective polarizer;
• a reflector disposed so that a line normal to the reflector intercepts the reflective polarizer at an angle of approximately 45 degrees;
• and
• a second retarder disposed between the reflective polarizer and the reflector,
• wherein the reflective polarizer, the reflector and the retarders are disposed to combine the first and the second light beam into a combined unpolarized light beam.