Patent•
Method for forming hologram
14 Oct 1987-
TL;DR: In this article, a converged spherical wave is vertically incident upon the 1st and 2nd spherical optical elements to generate an object wave with astigmatism and obtain a required astigmatic difference at the time of reproducing.
Abstract: PURPOSE:To simultaneously remove the difference between reproduced wavelength and formed wavelength and the influence of an astigmatic difference generated by a semiconductor laser by making a converged spherical wave vertically incident upon the 1st and 2nd spherical optical elements to generate an object wave with astigmatism and obtain a required astigmatism at the time of reproducing. CONSTITUTION:Converged spherical waves 17, 17' with wavelength lambda1 shorter than reproduced wavelength lambda2 are made incident upon a spherical convex lens 11 to generate negative spherical aberration waves and the generated waves are crossed with each other and led into a hologram material 13 formed on a base 14. Since a cylindrical lens 12 has curvature R' in a projecting direction 24, a distance of an object wave 15 in a projecting direction 23 from each crossing position to the hologram material 13 is different from that of an object wave 15' in the projecting direction 24 and the difference becomes the astigmatic difference. In addition to the object waves 15, 15', a reference wave 16 to be parallel beams with the wavelength lambda1 is made incident with incident angle thetac to expose the hologram material 13.
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Patent•
31 May 1990
TL;DR: In this paper, a reflection type hologram is exposed so that the angle 2 thetae between the laser light beams in two directions in the photosensitive material is different from the angle between the incident light and diffracted light which is the sum of an incidence angle and a diffraction angle in the reproduction.
Abstract: PURPOSE:To enable reproduction by a light source which differs in wavelength from a light source for exposure without varying the thickness of a hologram by performing the exposure during the reproduction so that the angle between laser light beams in two directions in a photosensitive material is different from the angle between incident light and diffracted light in the photosensitive material. CONSTITUTION:The reflection type hologram 3 where the wavelength of the laser light source for the exposure and the wavelength of the light source for the reproduction are different is exposed so that the angle 2thetae between the laser light beams in two directions in the photosensitive material is different from the angle 2thetar between the incident light and diffracted light which is the sum of an incidence angle thetar1 and a diffraction angle thetar2 in the reproduction. Consequently, when the light sources for the reproduction and exposure are different in wavelength, the hologram thickness need not be varied by a heat treatment, etc., and the reproduction is performed.
4 citations
Patent•
15 Aug 1990
TL;DR: In this paper, the convex surface of a thin and long transparent curved plate 30a is coated with the recording material 30b and arranged opposite a convex lens 28b, and when a point Q is regarded as a convergence point, converged light which is off-axis light irradiates the material as the reference light 34 to form interference fringes.
Abstract: PURPOSE:To form the ftheta lens actually and easily with a hologram by converging light through a lens after passing a spherical wave through the ftheta lens, and irradiating a recording material, arranged on a surface which is one wave front of the converged light and corresponds to the main surface of the ftheta lens, with a spherical wave as reference light. CONSTITUTION:The convex surface of a thin and long transparent curved plate 30a is coated with the recording material 30b and this convex surface is arranged opposite a convex lens 28b. The convex surface of the curved surface 30a is equal to the main surface S of the ftheta lens 18. Further, the interval between the convex surface of the curved plate 30a and the front surface of the convex lens 28b is equalized to the interval L between the main surface S and the rear surface of the convex lens 28a. The recording material 30b is irradiated with light which travels from the convex lens 28b to the curved plate 30a as object light and when a point Q is regarded as a convergence point, converged light which is off-axis light irradiates the material as the reference light 34 to form interference fringes. The light intensity distribution of the interference fringes is recorded on the recording material 30, and developed and fixed to form the holographic ftheta lens.
Patent•
06 Aug 1993
TL;DR: In this paper, an optical system laser scanning device is provided with a laser light source, a collimator collimating the laser beam, a cylindrical condensing lens and a rotary polygon mirror, and also constituted of the correcting lens system consisting of a recessed lens, a projected lens, and a drum.
Abstract: PURPOSE: To reduce a product cost by utilizing an inexpensive holographic and optical element and forming a correcting lens system. CONSTITUTION: An optical system laser scanning device is provided with a laser light source 11 emitting a laser beam, a collimator 12 collimating the laser beam, a cylindrical condensing lens 13 converging the laser beam and a rotary polygon mirror 14 reflecting the laser beam by a prescribed angle and also constituted of the correcting lens system consisting of a recessed lens 15 where the laser beam reflected by the rotary polygon mirror 14 is made incident and a projected lens 16 where the holographic and optical element 10 is jointed and constituted of a drum 17 where the laser beam reflected by the rotary polygon mirror 14 is corrected by the correcting lens system and scanning is executed on it.
Patent•
25 Dec 2008
TL;DR: In this paper, the authors proposed a method and a device for stably photographing a large quantity of same holograms in a hologram photosensitive material by multi-surface printing without increasing the size of an overall optical system.
Abstract: PROBLEM TO BE SOLVED: To provide a method and a device for stably photographing a large quantity of same holograms in a hologram photosensitive material by multi-surface printing without increasing the size of an overall optical system. SOLUTION: In this method of photographing holograms, a plurality of holograms arranged parallel to each other in at least one direction are photographed in the hologram photosensitive material 20 by multi-surface printing. A prism 10 of polygonal prismatic columnar shape is moved relative to fixedly arranged object light 21 and reference light 22 by stepping operation in the direction parallel to each side surface thereof. At least one of the object light 21 and the reference light 22 is directed from the corresponding side surfaces 12, 13 of the prism 10 at each stepping position. The object light 21 and the reference light 22 are alternately directed into the hologram photosensitive material 20 stuck on the other side surface 11 of the prism 10 to be stacked on each other for recording by interference. COPYRIGHT: (C)2009,JPO&INPIT
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Patent•
30 Apr 1983
TL;DR: In this article, the angle of incidence of a reproducing light to a hologram in accordance with the differnce of wavelength between recording and reproducing in the hologram reproducing system was proposed.
Abstract: PURPOSE:To prevent the occurrence of astigmatism in a reproduced image, by changing the angle of incidence of a reproducing light to a hologram in accordance with the differnce of wavelength between recording and reproducing in the hologram reproducing system. CONSTITUTION:Plural holograms 12 are arranged on concentric circles having a rotation center 11 on a rotary disc 10. A beam 21 emitted from a semiconductor laser 20 becomes a parallel luminous flux 23 through a coupling lens 22 and is made incident to holograms 12 on the rotary disc 10. Holograms 12 generated in this manner are illuminated with a reproducing illumination light having the same condition as a reference light. The angle of icidence of the reproducing ight to holograms is changed if the wavelength of the illumination light is different from that of the reference light, thereby correcting astigmatism.
2 citations
Patent•
30 Apr 1985
TL;DR: In this paper, the authors proposed to correct the chromatic aberration caused by a difference in wavelengths of the recording time and the reproducing time, and increase the sensitivity by deflecting at least one of two coherent light waves for recording a hologram reproduced by a wavelength different from a wavelength for recording the hologram.
Abstract: PURPOSE:To correct the aberration, and to increase the sensitivity by deflecting at least one of two coherent light waves for recording a hologram reproduced by a wavelength different from a wavelength for recording the hologram. CONSTITUTION:With respect to a hologram recording medium 8, a plane wave 10 of a wavelength lambda2 and a spherical wave 9 of a wavelength lambda2 are made incident at incident angles beta2 and alpha2. In the path of the spherical wave 9, a prism 11 having a prescribed vertical angle and refractive index is placed so that the direction of a wedge turns to a space placed between the spherical wave light 9 and the plane wave light 10, and said incident angles alpha2, beta2 are adjusted suitably. In this way, a chromatic aberration caused by a difference in wavelengths of the recording time and the reproducing time can be corrected, and the sensitivity due to a difference of the wavelengths is increased.
1 citations