US5973833A — High efficiency polarizing converter

Claim 1

Independent Claim 103 words

A planar polarizing converter structure, comprising: a planar beam splitter that receives light at an incident light-receiving surface and compresses incident light into plural distinct regions separated by dark regions; a flat reflective polarizer that receives light compressed into the plural distinct regions, transmits light of a first polarization sense and reflects light of an opposite second polarization sense; and a planar array of reflectors that are generally parallel to the incident light-receiving surface and positioned in the dark regions to receive the reflected light of the second polarization sense and redirect the light through the reflective polarizer in the first polarization sense.

Claim 2

Dependent Claim 103 words

A planar polarizing converter structure, comprising: a planar beam splitter that receives light at an incident light-receiving surface and compresses incident light into plural distinct regions separated by dark regions; a flat reflective polarizer that receives light compressed into the plural distinct regions, transmits light of a first polarization sense and reflects light of an opposite second polarization sense; and a planar array of reflectors that are generally parallel to the incident light-receiving surface and positioned in the dark regions to receive the reflected light of the second polarization sense and redirect the light through the reflective polarizer in the first polarization sense.

Claim 3

Dependent Claim 28 words

The polarizing converter structure of claim 1 further comprising a combiner with a planar array of light combining prismatic structures that receive light transmitted by the reflective polarizer.

Claim 4

Dependent Claim 16 words

The polarizing converter structure of claim 1 in which the reflectors are supported by frusto-prismatic structures.

Claim 5

Dependent Claim 30 words

The polarizing converter structure of claim 1 in which the beam splitter includes a planar array of light splitting prismatic structures that compress the incident light by total internal reflection.

Claim 6

Dependent Claim 41 words

The polarizing converter structure of claim 1 in which the reflectors in the planar array are supported on transmissive structures having pairs of sidewalls through both of which the flat reflective polarizer receives the light compressed into the plural distinct regions.

Claim 7

Dependent Claim 121 words

A planar polarizing converter structure, comprising: a planar array of light splitting prismatic structures that are positioned opposite and integral with an incident light-receiving surface, the array including inclined recesses positioned between adjacent pairs of the light splitting prismatic structures; a planar array of frusto-prismatic structures that extend into the inclined recesses positioned between adjacent pairs of the light splitting prismatic structures and include generally flat light exiting surface areas; a planar array of light combining prismatic structures positioned opposite and integral with an intermediate light receiving surface; and a flat reflective polarizer positioned between the light exiting surface areas of the planar array of frusto-prismatic structures and the light receiving surface of the planar array of light combining prismatic structures.

Claim 8

Dependent Claim 121 words

A planar polarizing converter structure, comprising: a planar array of light splitting prismatic structures that are positioned opposite and integral with an incident light-receiving surface, the array including inclined recesses positioned between adjacent pairs of the light splitting prismatic structures; a planar array of frusto-prismatic structures that extend into the inclined recesses positioned between adjacent pairs of the light splitting prismatic structures and include generally flat light exiting surface areas; a planar array of light combining prismatic structures positioned opposite and integral with an intermediate light receiving surface; and a flat reflective polarizer positioned between the light exiting surface areas of the planar array of frusto-prismatic structures and the light receiving surface of the planar array of light combining prismatic structures.

Claim 9

Dependent Claim 29 words

The polarizing converter structure of claim 6 in which the frusto-prismatic structures support reflective surfaces within the inclined recesses positioned between adjacent pairs of the light splitting prismatic structures.

Claim 10

Dependent Claim 23 words

The polarizing converter structure of claim 7 in which the reflective surfaces are generally parallel to and facing the light exiting surface areas.

Claim 11

Dependent Claim 35 words

The polarizing converter structure of claim 7 in which the frusto-prismatic structures include frustum surfaces that are generally parallel and opposed to the light exiting areas and only the frustum surfaces include the reflective surfaces.

Claim 12

Dependent Claim 30 words

The polarizing converter structure of claim 6 in which the planar array of light splitting prismatic structures and the planar array of light combining prismatic structures are formed of plastic.

Claim 13

Dependent Claim 33 words

The polarizing converter structure of claim 6 in which the light splitting prismatic structures totally internally reflect incident light propagating within the light splitting prismatic structures and normal to the incident receiving surface.

Claim 14

Dependent Claim 33 words

The polarizing converter structure of claim 6 in which the frusto-prismatic structures include transparent side faces and the light splitting prismatic structures converge light toward the transparent side faces of the frusto-prismatic structures.

Claim 15

Dependent Claim 21 words

The polarizing converter structure of claim 6 in which the light combining prismatic structures have prismatic faces that are oriented symmetrically.

Claim 16

Dependent Claim 21 words

The polarizing converter structure of claim 6 in which the light combining prismatic structures have prismatic faces that are oriented asymmetrically.

Claim 17

Dependent Claim 168 words

A polarizing converter structure, comprising: a generally flat reflective polarizer that is positioned to receive light from incident directions, transmits light of a first polarization sense, and reflects light of an opposed second polarization sense in reflection directions that are different from the incident directions; a reflector structure that has plural distinct reflector surfaces and is positioned along and transverse to the reflection directions with the reflector surfaces generally parallel to the reflective polarizer to reflect the light propagating in the reflection directions back toward the reflective polarizer and to reverse the polarization sense of the light, thereby directing to the reflective polarizer light of the first polarization sense, the reflector surfaces being supported on transmissive structures having pairs of sidewalls through both of which the flat reflective polarizer receives light from the incident directions; and a planar array of light combining prismatic structures receiving light of the first polarization sense from the reflective polarizer and directing the light in a common direction to form combined polarized light.

Claim 18

Dependent Claim 168 words

A polarizing converter structure, comprising: a generally flat reflective polarizer that is positioned to receive light from incident directions, transmits light of a first polarization sense, and reflects light of an opposed second polarization sense in reflection directions that are different from the incident directions; a reflector structure that has plural distinct reflector surfaces and is positioned along and transverse to the reflection directions with the reflector surfaces generally parallel to the reflective polarizer to reflect the light propagating in the reflection directions back toward the reflective polarizer and to reverse the polarization sense of the light, thereby directing to the reflective polarizer light of the first polarization sense, the reflector surfaces being supported on transmissive structures having pairs of sidewalls through both of which the flat reflective polarizer receives light from the incident directions; and a planar array of light combining prismatic structures receiving light of the first polarization sense from the reflective polarizer and directing the light in a common direction to form combined polarized light.

Claim 19

Dependent Claim 24 words

The polarization converter structure of claim 15 in which each of the reflector surfaces receives light from a different region of the reflective polarizer.

Claim 20

Dependent Claim 31 words

The polarization converter structure of claim 14 in which the reflective polarizer, the reflector structure, and the planar array of light combining prismatic structures are held in contact with one another.

Claim 21

Dependent Claim 33 words

The polarization converter structure of claim 14 further comprising a planar array of light splitting prismatic structures that receive incident light and direct it toward the reflective polarizer generally in the incident direction.

Claim 22

Dependent Claim 38 words

The polarization converter structure of claim 18 in which the reflective polarizer, the reflector structure, the planar array of light combining prismatic structures and the array of light splitting prismatic structures are held in contact with one another.

Claim 23

Dependent Claim 41 words

The polarizing converter structure of claim 14 in which the first and second polarization senses are opposed circular polarizations and the structure further includes a quarter-wave plate positioned between the reflective polarizer and the planar array of light combining prismatic structures.

Claim 24

Dependent Claim 81 words

In a liquid crystal display projector, the improvement comprising: a planar polarizing converter structure that includes a planar array of light splitting prismatic structures that are positioned opposite and integral with an incident light-receiving surface, the array including inclined recesses positioned between adjacent pairs of the light splitting prismatic structures, and a planar array of frusto-prismatic structures that extend into the inclined recesses positioned between adjacent pairs of the light splitting prismatic structures and include generally flat light exiting surface areas.

Claim 25

Dependent Claim 81 words

In a liquid crystal display projector, the improvement comprising: a planar polarizing converter structure that includes a planar array of light splitting prismatic structures that are positioned opposite and integral with an incident light-receiving surface, the array including inclined recesses positioned between adjacent pairs of the light splitting prismatic structures, and a planar array of frusto-prismatic structures that extend into the inclined recesses positioned between adjacent pairs of the light splitting prismatic structures and include generally flat light exiting surface areas.

Claim 26

Dependent Claim 63 words

The projector of claim 21 in which the polarizing converter further comprises a planar array of light combining prismatic structures positioned opposite and integral with an intermediate light receiving surface and a flat reflective polarizer positioned between the light exiting surface areas of the planar array of frusto-prismatic structures and the light receiving surface of the planar array of light combining prismatic structures.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2002-10-25	2003-04-26	2003-10-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2006-10-25	2007-04-26	2007-10-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2010-10-25	2011-04-26	2011-10-26	$7700.00	Window Closed / Lapsed

High efficiency polarizing converter

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