Method for holograms and holographic printings contact copying

The present invention relates to holography and is intended for copying holograms and holographic prints by means of contact copying by pulsed or continuous laser. The present invention can also be used for copying relief objects (coins, paintings) and for making Denysiuk-type holograms of these objects.

There is a known method of copying holograms according to U.S. Pat. 4416540, which does not expose a photosensitive material to a substrate and is placed parallel to (or below) the plane of the copying hologram, is illuminated by a narrow slit beam of coherent laser radiation. Coherent laser irradiation restores the image recorded in the hologram, that is, becomes an objective light beam, and at the same time acts on the unexposed photosensitive material as a support beam for coherent light, thereby interfering with the information contained in the copied hologram. The area of ​​the illuminated copying hologram illuminated by this slit beam is perpendicular to the projection of the incident light direction of the coherent light on the plane of the copying hologram and is forced to slide over the unexposed photosensitive surface in a direction parallel to the projection of

A disadvantage of said method of copying holograms is that a portion of the unexposed photosensitive material illuminated by the incident and support light beams incident on it remains unlit to form the image of the copied hologram. This is due to the laser beam's narrow slit-shaped coherent light beam reproducing the image of the copied hologram and simultaneously being the perpendicularity of the illumination area to the projection of the incident light beam onto the plane of the copied hologram. In this way, along with the useful image, parasitic noise is always recorded which degrades copy quality, the greater the area of ​​this parasitic illumination, the further the hologram is copied from the unexposed photosensitive material and the sharper the angle of incidence of the coherent light beam. Because the copied hologram and itself is usually inscribed on a photosensitive material and overlaid on some substrate, the space between the copied hologram and unexposed photosensitive material always exists, and the angle of incidence of coherent light can be as high as 15-20 degrees.

The object of the present invention is to improve the quality of reproduction of holograms and holographic prints and to enable the production of Denysiuk-type holograms of relief objects (coins, paintings, etc.).

The object is achieved by illuminating a narrow slit beam of coherent laser radiation in a method of exposing the photosensitive material to the substrate and placing it in parallel with a copied hologram or holographic print so that the exposed area of ​​the non-exposed photosensitive material is smooth. projection of the incident direction of the light into the plane of the copied hologram or holographic print, and causing the area to scroll in the direction of unexposed photosensitive material and copied hologram or holographic surface, perpendicular to the coherent light beam illuminating the replica hologram or holographic print and reproducing its image in the direction of the incident plane of said materials.

The length of the illuminated area of ​​the laser beam's narrow slit beam at the point where it falls on the photosensitive is at least 1% greater than the length of the copied hologram.

The laser beam may have a narrow elongated rectangle or an elongated oval.

Also according to the present invention, the laser radiation may be pulsed and the energy distribution of the radiation may be in the form of Π.

In addition, the copied material can be illuminated with coherent radiation of several colors simultaneously.

Also, the copied material can be illuminated by coherent radiation of different colors in turn.

The proposed method helps to improve the quality of copying of holograms or holographic prints and enables the copying of relief objects (coins, pictures, etc.) and the production of Denysiuk type holograms.

The proposed method is explained by drawings in which:

FIG. a schematic diagram (side view) explaining the proposed method of copying the holograms is shown;

FIG. a diagram illustrating the proposed method of copying the holograms is shown (front view);

FIG. shows a schematic of the proposed hologram copier.

The proposed approach consists of the following steps:

- unexposed photosensitive material 1, applied on a solid or flexible, transparent or opaque substrate 2, is placed on or under a copied hologram or holographic print 3 applied to the substrate 4 so that the planes of their surfaces are parallel (Fig. 1);

unexposed photosensitive material 1 and illuminates the copied hologram or holographic print 3 with a narrow slit-shaped coherent laser beam 5 incident on the copied hologram or holographic print 3 in direction 6 and reproduces the image therein (region 1 of FIG. 1);

- this image interferes with the excited coherent laser radiation in unexposed photosensitive material and captures a copy of the copied hologram or holographic print (Figure 1 area 8);

- a narrow slit-shaped coherent laser beam illumination area 5 is parallel to the projection of the illumination direction 6 into the surface plane of the copying hologram 3

- the illumination direction is selected so that the maximum luminance of the reproduced copied hologram is perpendicular to the plane of the copied hologram;

- the narrow-slit coherent laser beam illuminated area 5 of the copied hologram is at least 1% longer than the length 9 of the copied hologram or holographic print 3 and unexposed photosensitive material 1;

- area 5 is forced to move uniformly in the direction 10 perpendicular to the projection of the incident light direction 6 of the coherent light on the plane of the copied hologram or holographic print 3.

The device (Fig. 3) employs pulsed lasers 11 emitting three different wavelengths in the red, green and blue color spectral ranges as sources of coherent radiation.

Further, waveguides 12, computer controlled rotary polarizers 13, telescopic laser beam cleaners - spatial filters 14, polarization correction compensators 15, mirrors 16, and a tri-color summator-guide 17 are provided in the direction of the radiation of the laser 11. / Guide system 18 comprising a device with an elongated narrow rectangular or elongated oval slot 19.

The forming / deflection system 18 is mounted on a computer-controlled sliding motion actuator 20 capable of moving in the direction 21.

The forming / deflecting system 18 shapes and deflects the beam onto a mirror 22 positioned so that the reflected beam falls on the unexposed photosensitive material 1 in a direction such that its illuminated zone 5 is parallel to the illumination direction 6 of the copied hologram 3. so that the luminance maximum of this image is perpendicular to the surface plane 3 of the copied hologram.

The width 23 of the mirror 22 is selected to illuminate the area 5 of the reflected beam of coherent radiation by illuminating the desired area of ​​the copied hologram 3 while exposing the required area of ​​unexposed photosensitive material 1.

The length 24 of the mirror 22 is selected such that the illuminated area 5 of the coherent beam reflected by it is at least 1% longer than the length of the copied hologram 3 and the unexposed photosensitive material 1 9.

The method is realized as follows.

The wavelengths of each of the radiation emitted by the lasers 11 must correspond to the wavelength of the colored (or monochrome) copied hologram or holographic image 3, so that the color balance is controlled by waveguides 12 controlled by a computer and polarizers 13.

The beams of the lasers 11 are then cleaned by a telescopic laser beacon - spatial filters 14, and their polarization is compensated by polarization correction compensators 15.

The cleared beams are guided by mirrors 16 to the tri-color adder guide 17.

The rays emit from the summing guide 17 in the same direction and path to the laser beam forming / deflection system 18. This system forms a narrow rectangular (or elongated oval) slit 19 of laser beam reflected by a flat or other mirror 22 , falling on a copied hologram or holographic print 3 and unexposed photosensitive material 1.

The width 23 of the mirror 22 is selected such that the area 5 illuminated by the beam of coherent radiation reflected by the mirror 22, exhibits the required area of ​​unexposed photosensitive material 1 and illuminates the required area of ​​the copying hologram or holographic print 24. yes, so that the illuminated area 5 of the reflected coherent beam is at least 1% greater than the length of the copied hologram or holographic print 3 and of the unexposed photosensitive material 9. The narrow-slit laser radiation falls on the unexposed photosensitive material 1, applied on a flexible or rigid substrate and placed on or under the copying hologram or holographic print 3 in such a direction that the illuminated area 5 is parallel to the projection 6 of the copying hologram or holographic print 3 to the 3 plane of the copying hologram or holographic print.

The laser beamforming / deflection system 18 is mounted on a computer-controlled scrolling motion actuator 20 which provides its uniform motion in the direction 21, and thereby a coherent light beam in the direction 10 perpendicular to the incident direction of the coherent light beam illuminating the copied hologram. projection to the plane of the copied hologram, which in turn ensures an even exposure of the non-exposed photosensitive material, laser radiation by invoking the recording of holographic information copied therein.

The proposed method allows to improve the copying quality of holograms and holographic prints, as well as enables copying of relief objects (coins, pictures) and recording of these objects in Denysiuk type holograms.