DE1965448A1 - Method and arrangement for recording point holograms - Google Patents

Description

Patent attorney

Applicant: PhUI ₁ -J Pcftenivarwaifung GmbH.

File No. PHD- 1369
Registration dated: "J 9. Dec. 1969

PHILIPS PATENTVERWALTUNG GMBH., 2 HAMBURG 1, MÖNCKEBERGSTR.

"Procedure and arrangement for recording point holograms"

The present invention relates to a method and an arrangement for recording point holograms with a point hologram produced by shifting the point light source and repeated exposure.

An important area of application for point holograms is in semiconductor technology, where such holograms are used for imaging and take advantage of image multiplication from IC etch masks would like to. These holographic methods are known. Other applications are in the fields of optical data processing, optical data storage and the production of synthetic holograms.

Two basic methods are known for recording these point holograms:

a) A hologram is recorded from a lenticular lens. These known lens grids cannot meet the requirements of semiconductor technology, high resolution and good image quality. With a matrix of holes with holes of approx. 1 μm 0, which are placed in the focal points of this lens grid, the image quality and the resolution could be improved decisively. Because of the large manufacturing tolerance of the lens grids, the production of such an identical hole matrix is very difficult »

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You are bound to certain grid spacings. The grid spacing cannot be made arbitrarily small will.

b) Another recording technique involves moving a point light source step-by-step and repeating Exposing the point hologram recorded. With this step-by-step recording of the point hologram beam tracking is necessary according to the displacement of the point light source. For this Beam tracking with light guides are known for this purpose. The light guides have the disadvantageous property that they partially destroy the spatial coherence of the laser beam or have excessive losses. The step-by-step production of the hologram basically has the disadvantage that the repeated exposure results in poor hologram efficiency.

The object of the invention is to eliminate the lens hole matrix and its disadvantages. This is solved in that the real image of the dot grid is generated by a step-by-step recorded point hologram, the ongoing one Wavefront with a new reference wave one in the plane the real point-grid construction located point light reference source brought to interference and the interference pattern is recorded on a photographic disc.

With this step-by-step produced point hologram, only two pinhole diaphragms of approx. 1 / um 0 each are required for the recording. The hologram produced according to the invention has better imaging properties than conventional lenticular screens, while compared to the previously known step-by-step recording technique with its poor efficiency in the described new recording type, the efficiency is considerably lower.

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is improved. The point hologram to be produced step-by-step can be very easy and with good imaging properties can be recorded, with any pitch can be set. The latter is particularly important when you suck wants to record synthetic holograms. There is no need to manufacture such a pinhole diaphragm with a single hole Difficulties, and most importantly, all pixels are of the same quality.

The drawing illustrates exemplary embodiments of the invention. They show

Pig. 1 an arrangement for recording the hologram,

Pig. 2 shows an arrangement for the step-by-step recording of point holograms.

The beam coming from a laser is split through a beam splitter 1 split into partial beams 2 and 3. A deflection system 4 consisting of reflection prisms is required for a path length adjustment of the partial beams 2 and 3. With partial beam 2 is in a known manner with the help of the point light source 5 and the imaging optics 6 generate the complex conjugate reference wave that is used for the reconstruction of the Real dot grid 7 from the point hologram 8 is required. An optical imaging system is located behind this point grid 9, which images the exit pupil of the point hologram in the plane of the point hologram 10 to be newly produced. A complete transfer of information is thereby achieved.

The imaging system 9 can additionally be designed in such a way that it detects the imaging errors of the newly produced point hologram corrected differentially during reconstruction.

The partial beam 3 is used to illuminate a newly introduced

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th point light reference source 1.1, which is located in the plane of the real point grid reconstruction. The reference wave interferes with the wavefront of the dot matrix. The interference pattern is on a photo plate 10 in itself recorded in a known manner as an amplitude or phase hologram. In order to compensate for any imaging errors caused by the lens 9, it is useful to carry out the reconstruction insert this lens in the position corresponding to the recording in the beam path.

Beam tracking with deflecting prisms, for which mirrors can also be used, which allow the gradual recording of point holograms in a simple way and eliminates the disadvantages of light tracking with a light guide, is described with reference to FIG.

A beam splitter 12 splits an incoming collimated laser beam into partial beams 13 and 14. The optical alignment device 15 is required for a path length adjustment of the partial beams 13 and 14. The partial beam 13 is used for Illumination of the reference point light source 16. The partial beam is transmitted via the beam splitter and a fixed deflecting prism 17 steered into a fixed position. The deflecting prisms 18 and 19 and the point light source 20, consisting of a short focal length Microscope objective, in the focal point of which there is a small pinhole, are together on one Support mounted. A lateral parallel displacement of the laser beam is achieved by the deflecting prisms 18 and be moved sideways at the same time. A height adjustment is possible by means of a height adjustment that is separate from the deflecting prism 18 of deflecting prism 19. The separate movement is necessary because the beam height of deflecting prism 17 is fixed. With the deflecting prism 19, the beam direction can continue to be parallel to the partial beam 13 or any other direction can be set. Those from point light sources 16 and 20

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Exiting spherical waves are brought to interference and the interference pattern is recorded on a photo plate 21. The advantages of the two-step recording technique with conventional techniques would only be with greater effort accessible.

PATENT CLAIMS:

HHJ i) 'A 1 / \ * \ h 1

Claims (6)

PATENT CLAIMS: Method and arrangement for recording point holograms with a by shifting the point light source and repeated exposure produced point hologram, characterized in that from a step-by-step recorded point hologram the real image of the dot matrix is generated, the continuing wave front with a new reference wave brought point light reference wave located in the plane of the real point grid construction to interference and the interference pattern is recorded on a photographic plate. 2. The method according to claim 1, characterized in that for recording the output hologram for the step-by-step shift the point light source the illuminating coilimized The laser beam is directed one after the other via deflection elements in the direction of the displacement coordinates, and that for the displacement In one coordinate direction, that in the corresponding one The deflection in the direction of propagation learns to be shifted in this way is that the impinging beam is shortened or lengthened, and the positions of the subsequent deflecting elements Umlenkftmerit was constant in relation to day stay. 3. Arrangement for carrying out the Verfahron ^ n-I claim I, characterized in that to ?. ^{1 of} the plane of the real image (7) an optical image is located: ii (Q), day the Aus tr Lttopupille of the yunächat Punkbho Logramins (8) in the plane of the new a Punkbho Logram (K) J maps , 4. Arrangement according to claim 3, thereby germinated egg egg that the imaging system (9) is designed in such a way that so at reconstruction with the newly herd te llben Punittho lograiam (10) 10 9 8 2 7 /] U1 " ⁷ ~ 1965U8 - Y- its aberration in the same position as in the Image corrected differentially. 5. Arrangement for performing the method according to claim 2, characterized in that the point light source a perforated diaphragm (20) illuminated by the laser beam split off by means of a beam splitter (12) and the deflecting elements consist of mirrors or prisms (17, 18, 19). 6. Arrangement according to claim 3 or one of the following, characterized in that an optical adjustment device consisting of reflection prisms (4 or 5) is arranged in the beam path of the conjugate complex reference wave (2 or 13). 7/1341