WO2006092320A2 - Dispositif de mise en forme de faisceau d'un systeme optique, notamment d'un capteur optique de signaux, et systeme optique, notamment capteur optique de signaux muni de ce dispositif de mise en forme de faisceau - Google Patents

Dispositif de mise en forme de faisceau d'un systeme optique, notamment d'un capteur optique de signaux, et systeme optique, notamment capteur optique de signaux muni de ce dispositif de mise en forme de faisceau Download PDF

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Publication number
WO2006092320A2
WO2006092320A2 PCT/EP2006/001959 EP2006001959W WO2006092320A2 WO 2006092320 A2 WO2006092320 A2 WO 2006092320A2 EP 2006001959 W EP2006001959 W EP 2006001959W WO 2006092320 A2 WO2006092320 A2 WO 2006092320A2
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WO
WIPO (PCT)
Prior art keywords
light
light guide
beam shaping
shaping device
cross
Prior art date
Application number
PCT/EP2006/001959
Other languages
German (de)
English (en)
Other versions
WO2006092320A3 (fr
Inventor
Steffen Reichel
Michael Weisser
Ralf Domres
Axel Laschke
Burkhard Danielzik
Thomas Henrich
Matthias Ertl
Sigurd Dressler
Thomas Weingärtner
Thomas Reichert
Original Assignee
Schott Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE102005009642A external-priority patent/DE102005009642B4/de
Priority claimed from DE200510038999 external-priority patent/DE102005038999A1/de
Application filed by Schott Ag filed Critical Schott Ag
Publication of WO2006092320A2 publication Critical patent/WO2006092320A2/fr
Publication of WO2006092320A3 publication Critical patent/WO2006092320A3/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
    • G02B27/0938—Using specific optical elements
    • G02B27/0994—Fibers, light pipes
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/42—Coupling light guides with opto-electronic elements
    • G02B6/4201—Packages, e.g. shape, construction, internal or external details
    • G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
    • G02B6/4206—Optical features

Definitions

  • Beam shaping device of an optical system in particular of an optical signal pickup and optical system, in particular optical signal pickup with beam shaping device
  • the invention relates generally to optical signal pickups, in particular the invention relates to beam-forming devices for such devices.
  • Optical signal transducers are usually operated with laser diodes.
  • the beam profile of the light beams of a laser diode generally has an elliptical intensity distribution in cross section and an asymmetrical emission characteristic.
  • a profile is disadvantageous in order to achieve as small a symmetrical focus as possible with the optical system of a signal pickup, as required for writing and reading DVD data carriers.
  • the beam shaping by hiding parts of the beam is indeed a comparatively simple possibility, but at the expense of the luminous efficacy.
  • the invention is therefore based on the object to provide a beam shaping, in particular for optical signal pickup, which requires lower requirements for the adjustment and alignment of the optical elements and at the same time provides a good light output.
  • the invention provides a
  • Beam shaping device of an optical signal pickup which comprises a light guide having at least along a longitudinal portion of a cylindrically symmetric photoconductive region.
  • cylindrically symmetric is understood in the context of the invention as cylindrically symmetrical with respect to the optical axis.
  • the light guide at least along a longitudinal section, a reflection surface with a circular or circular.
  • An optical signal receiver according to the invention comprises, in addition to the beam-shaping device, a suitable light source.
  • a signal sensor is not only a reading device, but also a sense of the invention Read or write / read device understood. Accordingly, a beam shaping device according to the invention can also be used in CD or DVD burners or similar devices. 5 '
  • the optical waveguide has a reflective surface with a round cross-section along its entire length, which results in a light guide with a cylindrical reflection surface.
  • a beam-optical reflection takes place at an interface.
  • a plurality of modes in particular more or even significantly more than 10, can preferably be used with an optical waveguide according to the invention
  • optical fiber is therefore to be understood in contrast to a wave-optical single-mode fiber as a radiation-optical device.
  • the homogenization of the angular distribution is not through
  • NA denotes the numerical aperture
  • ⁇ denotes the wavelength of the light of the light source.
  • NA O, 3
  • ⁇ the wavelength of the light of the light source.
  • M 0.25 * V 2 , so that the diameter becomes correspondingly larger in order to conduct more than 10 modes.
  • a beam-shaping device allows Optical fiber in a surprising way much larger tolerances in the orientation of the light source.
  • the light guide comprises a transparent rod.
  • Such an element can be manufactured inexpensively with high cross-sectional accuracy.
  • the transparent rod can be used as the have a sheath of lower refractive index of the core and / or the manner of a graded-index optical fiber a continuously changing in the radial ⁇ direction, in particular decreasing refractive index, for example, in the manner of a waveguide a core and at least along at least a portion. In the latter case, the reflection then does not take place on a sharply delimited reflection surface. Also, at least a portion of the transparent rod may be loose.
  • This development also includes, in particular, a transparent bar which is sheathed along its entire length. An at least partially present coat is less sensitive to contamination or scratches on the surface and thereby scattered out scattering of light.
  • a jacketless or at least partially jacketless embodiment of the invention offers the advantage that .large numerical apertures can be achieved because the numerical aperture NA of a light guide in general by the relationship
  • NA (n! 2 -n 2 2 ) 1/2
  • ni is the refractive index of the light-guiding medium and n2 is the refractive index of the medium surrounding the light-guiding medium.
  • a high numerical aperture can be used to achieve good mixing and homogenization of the spatial intensity distribution can be achieved accordingly, in that the reflection surface of the light guide comprises a surface of a light-conducting medium adjacent to a gaseous medium or vacuum.
  • the numerical aperture also increases the detectable solid angle of the light emitted by the light source and thus the efficiency of the device according to the invention. It is favorable if the light guide has a numerical aperture of at least 0.3, preferably of at least 0.5, particularly preferably of at least 0.7.
  • Optical fiber is preferably substantially larger than the numerical aperture of a single-mode fiber.
  • Typical single-mode fibers have a refractive index difference of the order of 3 * 10 -3 with a core diameter of only a few micrometers. This results in numerical
  • the numerical aperture of a light guide according to the invention is preferably at least three times, preferably at least '5 times or even at least 7 times larger than a single-mode fiber to conduct the appropriate wavelengths.
  • the radiation characteristic is also dependent on the number of reflections of the light .
  • the number of reflections depends, among other things, on the ratio of length and diameter of the light guide. It is surprisingly found that a very good beam shaping 'already succeeds when the ratio of diameter d to length L of the photoconductive region of the light guide L / d at least 10, preferably at least 12, more preferably at least 15.
  • the diameter of the cylindrically symmetric region is at least 0.01 millimeter, preferably 0.1 millimeter. 'Is particularly preferably a diameter in the range of 0.5 to 1 millimeter. Expressed in units of wavelength, the diameter of the light-conducting region is preferably at least 10, preferably at least 20 times the wavelength of transmitted light, in particular the light of the light source with the inventive
  • the above indications preferably relate to the diameter of the light exit surface. Also for the light entry surface are large dimensions preferred to achieve a high light collection efficiency. For this purpose, the surface of the light entrance surface may be at least as large as the light exit surface or larger.
  • a light guide in the form of a rod thus presents a rigid or substantially rigid component at the large diameters used as compared to a thin glass fiber. This is also advantageous for facilitating the exact alignment with other optical components of an optical signal recorder.
  • the light guide, the light source and other components of the optical signal pickup, such as an objective lens and / or a beam splitter can be arranged fixed to one another.
  • the product of numerical aperture with the ratio of length L to diameter d of the light-guiding region of the light guide ie the size NA • L / d at least 10, preferably at least 12, more preferably at least 15 is.
  • a good mixing of the angular distribution of the emitted light is further achieved even if the diameter and length of the light guide are dimensioned so that the light transmitted through the light guide light of the light source at least 1.5 times on average, preferably at least an average of 2.0 times, particularly preferred is reflected at least 2.5 times in the light guide on average.
  • the dimensions of the light guide can accordingly also to the spatial intensity distribution be adapted to the light emitted from the light source.
  • a dust-tight encapsulation of the light guide can be provided in an advantageous development.
  • Preferred materials for the light guide are still glass or plastic. Plastic is easy and inexpensive to process, whereas glass generally has better optical properties. Of course, these two materials can also be combined, for example in the form of a plastic-coated glass rod.
  • the entrance and / or exit surface of the optical waveguide can continue to be particularly advantageous
  • Antireflection coating be provided to minimize reflection losses and to achieve high luminous efficiencies.
  • a focusing or defocusing element in particular a lens, arranged on the input side to the light guide.
  • the angular distribution of the input-side light beams can be widened to increase in this way the average number of reflections of the light beams in the optical fiber and thus to improve the homogenization properties of the beam shaping device.
  • light sources are available that are not circularly symmetrical.
  • a beam shaping device of an optical system in particular an optical signal pickup is provided, which has a light guide with a round light exit surface and a light entrance surface with a from the light exit surface comprising differing cross-section, wherein the light guide has a transition from the cross-sectional shape of the light entry surface in the cross-sectional shape of the light exit surface shape.
  • the optical waveguide along at least one section may have a shape that continuously transitions along the light guide direction from the cross-sectional shape of the light entry surface into the cross-sectional shape of the light exit surface.
  • the light guide has a larger area or the same area as the light exit surface.
  • the cross-sectional shape of the light guide may have an optional shape adapted to the spatial emission of the light source.
  • the light entry surface of the light guide may be rectangular or square. Rectangular shapes of the light entrance surface are particularly suitable for elongate light sources, such as for laser bars. Accordingly, in particular for such light sources, an elongate shape of the light entry surface of the light source is Fiber optic advantage.
  • a homogenization of the spatial light distribution can succeed even with elongated inlet openings, which have a ratio of length to width of at least 5 to 1.
  • a laser bar with 16 parallel laser diodes a light guide can be followed by a correspondingly shaped light entry surface. In this case, the light entry surface may have a length to width ratio of at least 16: 1.
  • transparent material can be hot pressed, so that a
  • Light guide is obtained with a round light exit surface and a light entrance surface with a different from the light exit surface cross-section, wherein the light guide has a transition from the cross-sectional shape of the light entrance surface in the Querschnitsform the light exit surface form.
  • the transparent material is for this purpose between at least two mold halves of a mold hot pressed.
  • the transparent material of the light guide does not have to be completely absorbed in the press mold or compressed along the entire length of the light guide.
  • a transparent rod with the cross-sectional shape of the inlet or outlet end at one end in a mold so. is transformed, that receives this end of the rod a different cross-sectional shape.
  • one end of a transparent rod is shaped in a mold so 'that the desired cross-section of this end is inspirational-, wherein the other, non-deformed end of the already having the desired second cross-section.
  • inductive heating of the mold and / or of the transparent material is suitable for heating.
  • the transparent rod to be reshaped can also comprise a core and a jacket with different refractive indices.
  • the numerical aperture of such a rod is preferably at least 0.3, more preferably at least 0.5.
  • a rod with core and cladding with a numerical aperture of at least 0.7 can also be used. It is also possible to apply a transparent jacket after hot pressing. This is for example advantageous if the rod is very much deformed to obtain the desired shape.
  • the optical fiber may also comprise a fiber bundle, or be composed of a plurality of fibers. These may be fused together or otherwise connected at least along a section. Accordingly, a transparent fiber bundle is at least partially fused together to produce such a light guide. It has been found that an ordered, regular arrangement of the individual fibers to achieve a homogenization of the angular distribution of the light of a light source is not required. Rather, it is preferred, especially at the light entry end, to combine the fibers in a disordered manner or without a regular azimuthal and / or radial arrangement.
  • the individual fibers have numerical apertures and / or diameter, as above for a single rod were called. Accordingly, it is also preferable not to use single-mode waveguides, but rather fibers that can conduct a plurality of modes, preferably more than ten, more preferably at least 20 modes.
  • a light guide for a beam shaping device of an optical system is accordingly produced by bonding the fibers of a fiber bundle together at least along a section.
  • the bonding is preferably carried out so that a light guide is obtained with a round light exit surface.
  • the light entry surface can then be produced with a cross section that differs from the light exit surface, wherein the light guide has a shape that changes from the cross sectional shape of the light entry surface into the cross sectional shape of the light exit surface.
  • the fibers used are in particular those fibers which, like typical optical fibers, have a sheath and a core with higher refractive indices.
  • it could also - in analogy to the embodiment with a shawlless transparent rod - also sheathless fibers used, and fibers with sheath and shanty fibers are combined. In this way, a larger optically effective, effective cross-sectional area is created at the light entry side and / or light exit side joining of the fibers.
  • the fibers can be easily rearranged to achieve a change in the cross-sectional areas of the inlet and outlet ends.
  • the cross-sectional area is retained.
  • a light guide can be obtained, which has a round light exit surface and a differently shaped, approximately rectangular or generally elongated shape, but which has substantially the same cross-sectional area.
  • the fibers of a fiber bundle are fused together at their ends.
  • the light guide comprises a plurality of fibers which are fused together at the light entrance and exit ends and are not fused together in an intermediate section.
  • a light-shaping device is provided, the optical waveguide of which ensures homogenization of the angular distribution of the incoming light and, on the other hand, is flexible due to the section in which the individual fibers are not connected to one another.
  • a light guide can be achieved with a fiber bundle connected at the ends, the fibers of which are not interconnected in an intermediate region to provide a flexible arrangement, also by a different manner of end-side connection of the fibers.
  • the fibers can also be glued as described above or cast into transparent material.
  • the material for the light guide can be made directly in a suitably shaped mold by hot pressing in the desired shape.
  • that too transparent material, in particular a fiber bundle in a metal ferrule are hot-pressed.
  • the ferrule is formed together with the material therein together.
  • the transparent material for the light guide is not formed by compressing mold halves of a mold, but a strand of transparent material is longitudinally pressed into a conically shaped mold and hot formed.
  • a metal ferrule can be used. It surrounds the strand along at least one section and is formed together with it by being pressed into the conical molding tool.
  • An optical system such as an optical signal pickup, which is equipped with a beam shaping device according to the invention is characterized, inter alia, by achieving a very homogeneous intensity distribution with respect to the azimuthal angular distribution, almost independently of the properties and dimensions of the light source.
  • the light can then be reused with high efficiency in other optical components of the system.
  • Even a laser bar arranged on the entrance side to the beam shaping device can, as already mentioned, be used as the light source and its radiation be azimuthally almost completely homogenized.
  • the beam-shaping device can also be arranged upstream of, for example, an optical fiber of the optical system. In this way, the light can, among other things a laser bar very efficiently in such an "optical fiber are introduced. In this case, therefore beside a homogenizing effect also focusing or concentration of the light about the optical axis take place.
  • the optical waveguide can then be oriented relative to the light source in such a way that the largest possible proportion of the light is coupled into the optical waveguide.
  • the light guide is conically shaped, so that in particular the cross sections of the reflection surfaces at the inlet and outlet ends have different diameters.
  • the light guide can then be arranged so that the end with the larger diameter or larger area forms the entrance end. In this way, additionally a focusing effect can be achieved.
  • an optical waveguide with a cross section of the light-conducting region which tapers from the inlet end to the outlet end can be provided for focusing.
  • the taper can be both a decrease in diameter and a decrease in the cross-sectional area of the photoconductive region.
  • the optical waveguide is used in the optical signal sensor in conjunction with a laser diode as the light source, since even laser diodes emit light with asymmetrical intensity distribution. Indeed This problem may also arise with light-emitting diodes, so that in this case the invention can also be advantageously used with a light-emitting diode as the light source.
  • the invention can be used particularly advantageously in conjunction with blue-emitting laser diodes. Especially with such laser diodes can because of the short wavelength very small focus. Diameter can be achieved so that can describe and / or read data carriers with a particularly high data density. Such laser diodes are planned, for example, for future generations of DVD devices 1 .
  • Fig. 1 is a schematic view of a
  • FIG. 3 shows an embodiment of a beam shaping device according to the invention with a loose fiber optic cable in encapsulation
  • 4A to 4C are longitudinal and cross-sectional views of an embodiment with elliptical Cross section at the entrance end of the light guide
  • FIG. 11 shows an optical system with a beam shaping device as shown in FIG. 9, FIG.
  • FIGS. 12A, 12B alternative method steps with a device as shown in FIGS. 12A, 12B,
  • Fig. 15 an embodiment of a light guide, as with the in Figs. 13A, 13B and 14A,
  • Fig. 1 is a schematic view of components of an optical signal according to the invention according to a first embodiment of the invention shown.
  • the optical signal sensor 1 is symbolized by a dashed box.
  • From a laser diode 20 light is emitted with a generally non-radially symmetric, but rather mostly elliptical intensity distribution.
  • the light subsequently impinges on the beam shaping device 3 according to the invention in the signal pickup.
  • this light beam comprises a light guide 5 which extends at least along one. • longitudinal section a cylindrically symmetric photoconductive
  • the optical waveguide 5 has, along at least one longitudinal section, a reflection surface with a round or circular cross-section.
  • a reflection surface with a round or circular cross-section.
  • glass and / or plastic is used as the material for the light guide 5.
  • the light entry surface 13 and the light exit surface 15 of the light guide 5 are each provided with antireflection coatings 16, 17, respectively, in order to improve the coupling and decoupling of the light.
  • FIGS. 1 and 2 A cross section through the light guide 5 is shown in Fig. 2.
  • a light guide 5 in the form of a transparent rod 5 with a laser diode 20 facing
  • the inlet end and an exit end for the light comprises this one core 7 and a jacket 9 surrounding the core along its entire length.
  • the jacket 9 has a lower refractive index than the core 7 in the manner of a waveguide. This results in a
  • Reflection surface 11 as an interface between the shell 9 and core 7.
  • the core 7 accordingly also forms the light-conducting region 8 of the light guide fifth
  • a gradient index light guide can be used in which in the radial direction no sharp refractive index jump is present, but at. in which the refractive index decreases continuously in the radial direction, starting from its optical axis, at least within a cylindrical section within the optical waveguide.
  • the light-conducting region is also cylindrically symmetric in this embodiment as well.
  • the core 7 further comprises a particularly easy to produce, substantially cylindrical shape with along the length L constant diameter d.
  • the cross section of the light-conducting region 8 or of the core 7 is in this case, in particular, round, or circular, along the entire length of the light guide 5.
  • the diameter of the core is at least 0.01 millimeter, preferably 0.1 millimeter. Particularly preferred is a diameter in the range of 0.5 to 1 millimeter.
  • the diameter of the photoconductive region is preferably at least 10, preferably at least 20 times the wavelength.
  • the reflection of the passing light at the circular interface results in a surprising manner to a good homogenization of the spatial intensity distribution.
  • This means in the context of the invention that an asymmetric angular distribution of the light is changed by means of the beam shaping device into a symmetrical or at least substantially more symmetrical angular distribution.
  • a high numerical aperture of the optical waveguide 5 is advantageous. Can be realized in a as in Figs. 1 to
  • the high numerical aperture in combination with the large diameter of at least 50 micrometers also leads to more than 10 modes, more preferably at least 20 modes are guided in the light guide. This is especially true when the diameter of the photoconductive region has at least 0.01 millimeter diameter.
  • the ratio of length L to diameter .d of the photoconductive region 8 of the optical fiber ,. L / d, is still for good homogenization at least 10, preferably at least 12, more preferably at least 15. It is particularly advantageous if the dimensions of the light guide are selected so that the product of numerical aperture of the light guide 5 with the ratio of length L to diameter d of the photoconductive region of the light guide, NA • L / d is at least 10, preferably at least 12, particularly preferably at least 15.
  • the length of the light guide 5 advantageously dimensioned such that: L> 10 • d / 0.35, preferably L> 12 • d / 0.35, more preferably L> 15 • d / 0.35.
  • Decisive for the homogenization of the radiation field of the laser diode is the number of reflections of the light rays at the
  • Reflection surface 11 The number of reflections depends both on the ⁇ entry position of a • light beam and on its angle. For all light rays passing through, however, it is easy to determine, for example, by means of a raytracing simulation, the mean value of the
  • the diameter and length of the light-conducting region of the light guide 11 can be dimensioned such that the light transmitted through the light guide of the laser diode 20 at least an average of 1.5 times, preferably at least an average of 2.0 times, more preferably at least 2.5 times average
  • Reflected light guide Even with such low values of the average reflections, the spatial distribution of the light is generally sufficiently well, in particular comparable to other known methods, such as beamforming, homogenized with anamorphic prisms.
  • the beam shaping device according to the invention allows greater tolerances than is the case with previously known solutions.
  • the angular distribution of the light beams emanating from the laser diode 20 is too small to obtain a sufficient average number of reflections, it is also possible, for example, optionally to have a lens 25 arranged on the input side to the light guide 5 . Focusing element can be used so that the angular distribution of the input-side light beams is widened.
  • the light beams are focused in the embodiment shown in FIG. 1 by means of a lens 22 onto a beam splitter 26.
  • the beams reflected at the beam splitter 26 then encounter ⁇ a controllable adjustment mirror 28, with which the laser beam, for example, for tracking the laser beam can be positioned.
  • the laser beam is then focused by means of an objective lens 24 onto the surface of an optical medium, for example a DVD.
  • the beams reflected back from the optical storage medium eventually pass through the beam splitter 26 and are then focused by a lens 23 onto a photodetector 30 and converted into electrical signals.
  • the photodetector 30 can be, for example, a four-quadrant detector
  • the structure of such an optical system with adjustment mirror 28 and multi-quadrant detector is known in the art, so that will not be discussed in detail here.
  • Intensity distribution which is almost or substantially radially symmetrical after passing through the beam shaping device 3, can obtain a particularly small focus diameter on the optical data carrier by focusing with the objective lens 24.
  • This makes it possible to read out and / or write smaller bit structures compared with an optical signal receiver without a beam shaping device 3 according to the invention.
  • the advantages of the invention are particularly important when using a blue-emitting laser diode 20 for reading and / or writing DVD discs of the next generation, since only with corresponding focusing properties of the optical system compared to previously used light sources ever a smaller focus with such blue lasers can generate.
  • FIG. 3 shows a further exemplary embodiment of a beam shaping device 3 according to the invention.
  • the light guide 5 of this exemplary embodiment has no sheath. Accordingly, the entire optical waveguide 5 here forms the light-conducting region 8 and the reflection surface 11 is the peripheral outer surface 10 of the optical waveguide 5.
  • the optical waveguide 5 again has round or circular cross-section along its entire length, so that it has the shape of the core 7 of the in the. 1 and 2 and the photoconductive region is also cylindrically symmetrical with respect to the optical axis of the optical fiber 5.
  • a dust-tight encapsulation 35 is provided, which surrounds the light guide 5.
  • the reflection surface 11 of the light guide 5 is a to a gaseous medium -in the present example, the enclosed in the cavity air-adjacent surface of the photoconductive medium of
  • FIG. 4A to 4C show longitudinal and cross-sectional views of a further embodiment of a beam shaping apparatus 3 according to the invention.
  • FIG. 4A shows a longitudinal section through the light guide 5
  • FIG. 4B shows a cross-sectional view at the inlet end 13
  • FIG. AC shows a cross-sectional view at the outlet end of the light guide 5th
  • the optical fiber has a conically shaped, light-entry side portion . 40 " and a cylindrical, light exit-side section 41.
  • the section defining the light-guiding region 8 formed by the core 7 has Reflection surface 11 similar to the example shown in FIGS. 1 and 2 a round, or circular cross-section. This is again illustrated by the cross-sectional view of FIG. 4C.
  • This embodiment of the invention is advantageous because this shape of an elliptically deformed angular distribution of
  • Light intensity of a laser diode is adjusted so that the coupling is improved.
  • the small semiaxis of the elliptical reflection surface at the entrance end " 13 essentially corresponds to the radius of the circular reflection surface at the exit end 15, the cross-sectional area becomes smaller, thereby additionally concentrating and focusing the light in the light guide 5 in addition to the beam shaping.
  • This can of course also be achieved, for example, with a light-guiding region with a continuously circular cross-section tapering from the inlet end 13 to the outlet end 15.
  • FIGS. 5 to 8 show angular distributions of the light intensity before and after the beam shaping by means of a beam shaping device 3 according to the invention.
  • FIGS. 5 and 7 show distributions before beam shaping.
  • Fig. 7 shows the beam profile in a plane perpendicular to the propagation direction.
  • the intensity along the drawn in Fig. 7 directions A and B is shown.
  • the beam profile is strongly asymmetrical, in the angular distribution B shown in FIG. 5 even several maxima can be seen.
  • FIGS. 6 and 8 show the corresponding distributions after the beam formation, that is to say after the exit from the light guide. As is clear from these figures, even a highly asymmetric angular distribution by means of the invention can be completely converted into a radially symmetric distribution.
  • FIG. 9 shows a schematic view of a further embodiment of a device according to the invention.
  • Beam shaping device 3 for an optical system such as an optical signal pickup.
  • the embodiment shown in this example has a light guide 5 with a round light exit surface 15 and a light entry surface 13 with a different cross section from the light exit surface 15, wherein the light guide further has one of the cross sectional shape the light entrance surface in the cross section shape of the light exit surface has transitional shape.
  • the light guide goes along at least a portion and along the
  • Light guide direction in cross section continuously from the cross-sectional shape of the light entry surface 13 in the cross-sectional shape of the light exit surface 15 via.
  • the light entry surface 13 has a stretched shape which is suitable for collecting light from a corresponding elongate light source and for guiding it along the light guide 5 to the light exit surface 15.
  • the Cross-sectional shape of the light entrance surface rectangular.
  • the light entry surface but may also be a different type of elongated shape, for example with rounded corners or limiting semi-circles as shown in FIG. 10A or FIG. 1Ob, or even in the form of a flattened polygon, such as the hexagonal shape shown in 'Fig.- IOC exhibit. If elongate light sources are used, it is advantageous if the light entry surface 13 of the light guide 5 has an elongate shape with a length to
  • Width of at least 5 to 1 has.
  • laser bars can be used as light sources.
  • the light guide 5 must generally have no cylindrical, light exit-side section, but can also only at the exit surface 15 finally in a. go over circular cross-sectional shape.
  • the optical waveguide 5 is cylindrical, at least in the region of the light exit surface 15, in order to achieve a good
  • the optical waveguide is preferably a core-clad optical fiber, in particular having such ratios of refractive indices of the materials as used in the examples shown in Figs. 2, 4A-4C, accordingly, such optical waveguide has a numerical aperture of preferably at least 0.3, more preferably at least 0.5.
  • a core-shell rod with a numerical aperture of at least 0.7 can be used, for example when very divergent light sources are used should be. If scattering effects due to depositing dust or other soiling are not critical, analogous to the example shown in FIG. 3, a barless bar can also be used.
  • Fig. 11 shows an optical system denoted as a whole by the reference numeral 2, in which a beam shaping device as shown in Fig. 9 is used, which comprises a light guide 5 with an elongate rectangular light entrance surface 13. '
  • a laser bar 50 is arranged so that its
  • Light exit opening 51 opposite to the light entry surface 13 of the light guide 5 is located.
  • the light entry surface 13 is oriented in accordance with the elongated light exit opening 51 of the laser bar 50, so that a maximum of the emitted light can enter the light guide 5.
  • the beam shaping device is arranged upstream of an optical fiber 54 3, so that the light guide can couple 5 homogenized exiting light into the optical fiber from the 'light exit surface 15 °.
  • This optical system can also be, for example, an optical signal pickup.
  • the system with the general components shown in FIG. 11, light source (here by way of example of the laser bar 50), beam shaping device and optical fiber 54, can also be an optical transmitter.
  • FIGS. 12A and 12B show an arrangement and method steps for producing a
  • Beam shaping device in particular with such a light guide, as shown in FIGS. 4A to 4C or FIG. 9.
  • the method and apparatus for carrying out this method are based on hot-pressing transparent material to obtain a light guide having a round light exit surface and a light entrance surface having a cross section different from the light exit surface, the light guide being one of the cross-sectional shape of the light entrance surface has in the Querschnitsform the light exit surface transitional shape.
  • the transparent material between the pressing surfaces 59, 63 of two mold halves 57, 61 of a mold is hot-pressed into at least two mold halves of a mold of the apparatus designated as a whole by the reference numeral 55.
  • the 'heating the mold and of the transparent material takes place inductively by means of inductors 70.
  • a transparent rod 65 particularly preferably made of glass with the cross-sectional shape of the outlet end at one end in the mold so transformed that this end of the rod receives a different Querterrorismsfo 'rm.
  • FIG. 12 shows, the rod as it between the pressing surfaces 59, 63 of the mold halves 57, is inserted 61 before pressing.
  • Fig. 12B the arrangement after completion of pressing together
  • the end inserted in the mold has now been given an elongated, rectangular shape by pressing.
  • FIGS. 13A, 13B show an alternative procedure for producing a light guide, for a beam shaping device according to the invention.
  • a fiber bundle 76 is used as a transparent material.
  • the fiber bundle 76 is surrounded by a ferrule 75, preferably of metallic material.
  • Fig. 13A shows the fiber bundle 76 with ferrule 75 inserted in the mold.
  • the fiber bundle 76 with the ferrule 75 is then hot-pressed, whereby, as in the example shown in Figs. 12A, 12B, the pressing surfaces 59, 63 of the mold halves 57, 61 are pressed together.
  • an inductive heating is used by means of inductors 70 also in this' example.
  • the ferrule 75 Upon hot pressing, the ferrule 75 also deforms to provide an elongate cross-sectional shape of one end of the optical fiber as shown in FIG. 13B, with the individual fibers of the fiber bundle joined into a fused fiber bundle 77.
  • the entire fiber bundle after joining has the intended cross-sectional shape. Accordingly, the fibers are combined in particular at the light entry end without regular arrangement.
  • the fibers of the fiber bundle can furthermore also be sheathless in order to increase the optically effective, effective cross-sectional area at the ends.
  • FIGS. 14A, 14B show a further device 55 and method steps for producing optical fibers for a beam shaping device according to the invention. In this device, hot pressing does not proceed as in the devices shown in Figs. IIA, IIB, 12A, 12B
  • a strand of transparent material in the form of a fiber bundle 76 in the longitudinal direction in a conically shaped mold 80 is introduced (Fig. 14A) and subsequently pressed by further advancing and hot formed .
  • the mold has a channel 81 'with a conical portion 82nd on, which narrows in the direction indicated by the arrow insertion.
  • the fiber bundle 76 is surrounded by a deformable metallic ferrule 75 at least in the region which is to be hot-formed.
  • the fibers can be bonded by gluing.
  • Fig. 15 shows a waveguide 5 a
  • the light guide 5 has a plurality of each other at least along a portion with each other fused fibers, or a fiber bundle fused along this section.
  • the fibers are fused together at the light exit end along the cylindrical longitudinal section 41 with the light exit surface 15 and at the light entry end along the longitudinal section 43 with the light entry surface 13.
  • the fibers are not fused together in a portion 43 lying between the sections 41, 43 ' .
  • the light guide 5 even remains flexible.
  • the fused material is in each case surrounded by a metallic ferrule 75.
  • Homogenization of the azimuthal intensity distribution is cylindrical, inter alia, in ⁇ reaches the light exit side portion '41st
  • the light guide 5, as shown in FIG. 15, can be manufactured as follows: The light entry side, flattened portion 43 ' with a correspondingly elongated
  • Inlet opening 13 can be made, for example, by a press mold of a device 55 as described with reference to FIGS. 13A, 13B, by hot pressing and fusing or gluing.
  • a press mold of a device 55 as described with reference to FIGS. 13A, 13B
  • hot pressing and fusing or gluing for example, a hot pressing and fusing or even bonding of the fiber bundle 76 in.
  • a conical mold according to the method explained with reference to FIGS. 14A, 14B offers.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Couplings Of Light Guides (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

L'invention vise à homogénéiser la répartition spatiale d'intensité d'un capteur optique de signaux. A cet effet, un dispositif de mise en forme de faisceau d'un capteur optique de signaux comprend un guide d'onde optique qui présente une zone de guidage de lumière cylindrosymétrique au moins le long d'un segment longitudinal.
PCT/EP2006/001959 2005-03-03 2006-03-03 Dispositif de mise en forme de faisceau d'un systeme optique, notamment d'un capteur optique de signaux, et systeme optique, notamment capteur optique de signaux muni de ce dispositif de mise en forme de faisceau WO2006092320A2 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102005009642.5 2005-03-03
DE102005009642A DE102005009642B4 (de) 2005-03-03 2005-03-03 Optischer Signalaufnehmer mit Strahlformungseinrichtung
DE102005038999.6 2005-08-16
DE200510038999 DE102005038999A1 (de) 2005-08-16 2005-08-16 Strahlformungseinrichtung eines optischen Systems, insbesondere eines optischen Signalaufnehmers und optisches System, insbesondere optischer Signalaufnehmer mit Strahlformungseinrichtung

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WO2006092320A2 true WO2006092320A2 (fr) 2006-09-08
WO2006092320A3 WO2006092320A3 (fr) 2007-06-07

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PCT/EP2006/001959 WO2006092320A2 (fr) 2005-03-03 2006-03-03 Dispositif de mise en forme de faisceau d'un systeme optique, notamment d'un capteur optique de signaux, et systeme optique, notamment capteur optique de signaux muni de ce dispositif de mise en forme de faisceau

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11867630B1 (en) 2022-08-09 2024-01-09 Glasstech, Inc. Fixture and method for optical alignment in a system for measuring a surface in contoured glass sheets

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4932747A (en) * 1989-09-07 1990-06-12 The United States Of America As Represented By The Secretary Of The Navy Fiber bundle homogenizer and method utilizing same
US5661837A (en) * 1994-06-29 1997-08-26 Nikon Corporation Illumination optical apparatus and scanning exposure apparatus using the same
US6272269B1 (en) * 1999-11-16 2001-08-07 Dn Labs Inc. Optical fiber/waveguide illumination system
EP1241510A1 (fr) * 2001-03-13 2002-09-18 Kabushiki Kaisha Toshiba Convertisseur de taille image, module laser à semi-conducteurs et dispositif laser à fibre optique
US6595673B1 (en) * 1999-12-20 2003-07-22 Cogent Light Technologies, Inc. Coupling of high intensity light into low melting point fiber optics using polygonal homogenizers

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4932747A (en) * 1989-09-07 1990-06-12 The United States Of America As Represented By The Secretary Of The Navy Fiber bundle homogenizer and method utilizing same
US5661837A (en) * 1994-06-29 1997-08-26 Nikon Corporation Illumination optical apparatus and scanning exposure apparatus using the same
US6272269B1 (en) * 1999-11-16 2001-08-07 Dn Labs Inc. Optical fiber/waveguide illumination system
US6595673B1 (en) * 1999-12-20 2003-07-22 Cogent Light Technologies, Inc. Coupling of high intensity light into low melting point fiber optics using polygonal homogenizers
EP1241510A1 (fr) * 2001-03-13 2002-09-18 Kabushiki Kaisha Toshiba Convertisseur de taille image, module laser à semi-conducteurs et dispositif laser à fibre optique

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11867630B1 (en) 2022-08-09 2024-01-09 Glasstech, Inc. Fixture and method for optical alignment in a system for measuring a surface in contoured glass sheets

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