RU97106147A - HOLOGRAPHIC DEVICE FOR FORMING AS MINIMUM OF THE FIRST AND SECOND BEAMS OF LIGHT, SEPARATED BY ANGLES AND THE PROJECTOR OF IMAGES IN WHICH IT APPLIES - Google Patents

Claims (11)

1. A holographic device for forming at least the first and second light beams separated by angles, equally plane-polarized, containing holograms, characterized in that the holograms are made in the form of the first and second holograms, practically coplanar and superimposed so that they are illuminated by one and the same beam (A) of unpolarized light of at least the first and second specified spectral compositions, while both of these holograms are registered so that in the volume of each of them the axis of the diffracted beam is perp direc- tions of said incident beam in this layer, said diffracted beams (B, C) forming said first and second light beams of the same polarization, separated at the corners and having a first and second predetermined spectral compositions, respectively.  2. The device according to claim 1, characterized in that the said holograms are placed between two adjacent glued prisms of optical material.  3. The device according to p. 2, characterized in that the said holograms are registered in the material with a refractive index (n) practically equal to the refractive index of the material of these prisms. 4. The device according to p. 3, characterized in that the holograms are illuminated at an angle of incidence of 45 ^o , the axis (B, C) of the beams diffracted by these holograms have a point of intersection on the axis of the beam (A) and lie in a plane perpendicular to this axis.  5. The device according to any one of paragraphs. 1 to 4, characterized in that it contains a third hologram that is practically coplanar to the other two, registered so as to form a diffracted plane-polarized light beam of a third predetermined spectral composition, the axis of which is coplanar to the axes of two other diffracted beams and has a common intersection point with them. 6. The device according to any one of paragraphs. 1 to 4, characterized in that it contains a third hologram not coplanar to the other two, recorded in a material with a refractive index (n ₅ ) different from the refractive index (n) of the other two, and set to form a third diffracted beam (D) with an axis not coplanar to the axes of the beams diffracted by the first and second holograms, and perpendicular in the volume of the third hologram to the axis A of the illuminating beam common to all three holograms, the above third beam being linearly polarized, like the other two, and third predetermined spectral composition.  7. The device according to claim 6, characterized in that it contains a third prism (6), wedge-shaped, placed between two other prisms, the first and second holograms being sandwiched between the face of this third prism and the face of one of the other prisms, while the third the hologram is sandwiched between the other face of this third prism (6) and the face of the other of the prisms, and the planes of the holograms intersect on an edge common to three prisms. 8. The device according to claim 7, characterized in that the angle of inclination (α) of the third diffracted beam to a plane containing the axes of two other diffracted beams is associated with the angle (α _k ) at the apex of the wedge-shaped prism at the named edge and with the refractive indices of the materials elements of the device, the ratio:

n is the refractive index of the first and second holograms,
n ₅ is the refractive index of the third hologram.  9. The projector of images displayed on a matrix screen with liquid crystal cells (B, V, R) located close to the raster of optical microlenses installed to focus each of them at least two beams of polarized light of a given spectral composition on at least two screen cells, differing the fact that it contains at least one holographic device according to any one of paragraphs 1 to 8 for illuminating the microlenses of the raster (16) with at least two light beams of the above spectral compositions.  10. The projector according to claim 9, characterized in that it contains the first and second holographic devices illuminating each individual area of the microlens raster, the first device being illuminated directly by the light source, and the second by a zero-order beam of holograms of the first device.  11. The projector according to claim 10, characterized in that it contains a half-wave plate and a pair of mirrors located in the path of the zero-order diffraction beam of the first device in order to rotate the polarization plane of the above beam and shift its axis in the direction of the axis of the second device.