RU96120353A - NATURAL WHITE LIGHT CONVERTER TO PLANE-POLARIZED LIGHT - Google Patents

Claims (1)

1. A converter of natural white light into plane-polarized light, containing a) a source (1) of a beam of natural white light, b) a divider (3) of the said beam by the reflected beam and transmitted beam, each of which mainly consists of one of two mutually orthogonal plane-polarized components ( P, S) the light emitted by the source (1), c) the rotator (6), designed to rotate the plane of polarization of the predominant component of one of the beams emerging from the divider, until it reaches a polarization state identical to the polarization state of the predominant component of another beam, and d) means for combining both output beams of the same polarization into one light beam, characterized in that said beam divider (3) is made in the form of a package of alternating plane-parallel plates of two different optical media with refractive indices (n _l and n _m) respectively, and thickness of each of these plates is much greater than the coherence length of the light emanating from the source, the angle of incidence (θ) of the beam from the source (1) on the second plate (10 ₂₎ op packet edelyaetsya of conditions

where θ _b is the angle of incidence on the named second plate (10 ₂ ) with a refractive index n _l equal to the Brewster angle. 2. The Converter according to claim 1, characterized in that the angle of incidence (θ) of the beam on the second plate (10 ₂ ) of the package is determined by the formula
θ _b ≤ θ ≤ θ ₂ ,
where θ ₂ is the angle of incidence of the beam from the source (1) on the second plate (10 ₂ ), for which the intensity of the reflected part of the S-component of light is equal to the intensity of the transmitted part of the P-component. 3. The Converter according to claim 1, characterized in that the angle of incidence (θ) of the beam from the source (1) to the second plate (10 ₂ ) of the package (3) is θ = θ _b .
4. The Converter according to any one of claims 1 and 3, characterized in that it contains a reflector (5, 5 ') mounted on the path of propagation of the light beam passing through the divider behind the rotator (6) so that the beams reflected by the packet ( 3) and a reflector (5, 5 '), combine to form one beam with predominant S-type polarization.  5. The Converter according to claim 4, characterized in that the said reflector is made in the form of a second set (5) of plates of the same type as the first set (3).  6. The Converter according to claim 2, characterized in that it includes a polarizer (12) mounted on the propagation path of both beams formed by the divider (3), using a means for combining them and oriented so that only one same predominant component of both beams. 7. The converter according to one of claims 1 to 6, characterized in that the package (3, 5) consists of glass plates (10 _i ), separated by air gaps (11 _i ). 8. The transducer according to one of claims 1 to 6, characterized in that the packet (3) is sandwiched between the respective faces of two identical prisms with a refractive index (n _l ) adjacent to the extreme plates of the packet having the same refractive index (n _m ).  9. The Converter according to claim 1, characterized in that the package (3) consists of only one plate made of a material with a high refractive index.  10. The Converter according to claim 1, characterized in that the package (3) consists of only one plate formed by an air gap between two prisms of material with a high refractive index.  11. The Converter according to claim 1, characterized in that one of the two optical media of the packet (3) is a birefringent material, and the other medium is isotropic, one of the main refractive indices of the birefringent material being equal to the refractive index of the isotropic medium.  12. The Converter according to one of claims 1 to 11, characterized in that the rotator of the plane of polarization (6) is installed on the propagation path of the beam passing through the divider (3). 13. The Converter according to one of claims 1 to 12, characterized in that the polarization plane rotator (6) is made in the form of any one element from the group of elements consisting of one half-wave plate, an image rotator of 90 ^o , a plate of optically active material, element on liquid birefringent crystals.  14. The Converter according to item 13, wherein the half-wave plate (6) is made in the form of any one element from the group of elements consisting of a plate of mica, a sheet of birefringent polymer, a cell on liquid birefringent crystals.  15. The converter according to claim 12, characterized in that the polarization plane rotator (6) is made in the form of a porous glass plate.  16. A video projector containing a matrix (8) of elements on liquid crystals and a source (1) of natural white light, characterized in that it includes a converter according to any one of claims 1 to 15, located between the source (1) and the matrix ( eight).