JP2012173320A - Optical wiring board, laser beam multiplexing module, and projector using those - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical wiring board and a laser beam multiplexing module which have a small body, are easily mounted, and can effectively reduce speckle noise; and a projector using those.SOLUTION: On an optical wiring board, one flexible substrate, a plurality of cores which is formed on the flexible substrate and functions as a transmitting path of an optical signal, and a clad, covering a surface of the flexible substrate on which the cores are arranged and the plurality of the cores, are integrally configured. End surface of the plurality of the cores is arranged on one end surface side of the flexible substrate, and one uniting core is formed by optically uniting the plurality of the cores near the other end surface side of the flexible substrate. An end surface of the uniting core is arranged on the other end surface side of the flexible substrate.

Description

  The present invention relates to an optical wiring board for combining laser beams, a laser beam combining module using the same, and a projector using these.

  Laser light sources are used as light sources for various optical devices because they are small and have high output, low power consumption and long life.

  A projector, which is one of the optical devices, performs video viewing or conference presentation by projecting video on a screen. Miniaturization and high brightness are required. It is rapidly spreading as an effective solution.

  A projector using a laser light source generates white light by combining laser light of three wavelengths of red (R), green (G), and blue (B), and uses the white light as a light source. Here, as a device that multiplexes laser beams of three wavelengths, a multiplex device that combines three optical fibers (photonic crystal fibers) to form one optical fiber (photonic crystal fiber) is disclosed in Patent Document 1. It is described in.

  Here, in a projector using a laser light source, flicker (speckle noise) caused by interference of adjacent light on a screen or the like becomes a problem. However, since the laser light output from the laser light source generates various speckle patterns spatially during transmission through the optical fiber, speckle noise can be reduced. Patent Document 2 describes that the longer the length of the optical fiber, the higher the effect of reducing speckle noise.

  Patent Document 3 discloses a technique for reducing speckle noise by reducing the coherence of laser light by the optical path length difference.

JP 2007-171471 A JP 2010-78622 A JP2011-2571A

  However, since the conventional optical component (multiplexing device) has a structure in which three optical fibers are combined to form one optical fiber, the handling of individual (separate) optical fibers is complicated, and the inside of the optical apparatus It took a long time to wire in. Further, in order to reduce speckle noise, the longer the length of the optical fiber, the more difficult it is to handle and a storage space is required, which makes it difficult to reduce the size.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an optical wiring board and a laser beam multiplexing module that can be reduced in size and mounted easily and can effectively reduce speckle noise, and a projector using these.

  In order to achieve the above object, the invention according to claim 1 is directed to a flexible substrate, a plurality of cores formed on the flexible substrate and serving as optical signal transmission paths, and the flexible substrate on which the cores are disposed. In the optical wiring board in which the surface of the plurality of cores and the clad covering the plurality of cores are integrally formed, the end surface of the plurality of cores is disposed on one end surface side of the flexible substrate, and the other end surface side of the flexible substrate In the vicinity, the plurality of cores are optically coupled to form one coupled core, the end surface of the coupled core is disposed on the other end surface side of the flexible substrate, and the plurality of cores are formed on the flexible substrate. The optical path lengths from the core end face disposed on one end face side to the coupling core are different from each other.

  The invention according to claim 2 is the optical wiring board according to claim 1, wherein at least two cores of the plurality of cores have a curved structure arranged periodically.

  The invention according to claim 3 is the optical wiring board according to claim 1 or 2, wherein the peaks of the plurality of curved structures and the bottoms of the curves are on a straight line perpendicular to the optical axis, or the above It is in the vicinity of an orthogonal straight line.

  The invention according to a fourth aspect is the optical wiring board according to the first to third aspects, wherein the periodically arranged curved structures are a Sin curve, a circular arc curve, a parabolic curve, and a conic curve.

  A fifth aspect of the present invention is a laser light multiplexing module comprising a plurality of lasers having different wavelengths and the optical wiring board according to any one of the first to fourth aspects, and is disposed on one end face side of the flexible substrate. Laser light from a plurality of lasers having different wavelengths is input to the plurality of core end faces, and laser light having different wavelengths is combined from the end face of the coupling core formed on the other end face side of the flexible substrate. Is output.

  In the invention according to claim 6, the laser beams having different wavelengths are red, green, and blue wavelengths, and the laser beams having different wavelengths are combined by the coupling core to become white light. 6. The laser beam multiplexing module according to claim 5, which is output from

  The invention according to claim 7 is a projector using the laser beam multiplexing module according to claim 5 or 6 as a light source.

  According to the present invention, it is possible to realize an optical wiring board, a laser beam multiplexing module, and a projector using these, which can be easily reduced in size and can effectively reduce speckle noise.

FIG. 1 is a top view of an optical wiring board showing a preferred first embodiment of the present invention. FIG. 2A is a front view of one end face of the optical wiring board 1 of the present invention. FIG. 2 (2) is a front view of the other end face of the optical wiring board 1 of the present invention. FIG. 3 is a diagram for explaining the overlapping of cores due to the phase relationship of a plurality of cores of the optical wiring board of the present invention. FIG. 4 shows the configuration of the laser beam multiplexing module of the present invention.

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a top view of an optical wiring board 1 showing a preferred first embodiment of the present invention.
One end face of the optical wiring board 1 is formed with end faces 2a, 3a, 4a of the cores 2, 3, 4 serving as transmission paths for the three laser beams, and the three cores 2 in the plane of the optical wiring board 1 are formed. , 3, 4 are coupled by a coupling portion 5 to form one core 6, which is disposed up to the other end surface of the optical wiring board 1 to form a core end surface 6 a. Here, the coupling unit 5 can use a general Y-branch structure, an MMI (multimode interferometer), or a Mach-Zehnder interferometer structure.

  FIG. 2 is an end face of the optical wiring board 1. (1) is one end face (left end face in FIG. 1) of the optical wiring board 1, and (2) is the other end face (right end face in FIG. 1) of the optical wiring board 1. The end surfaces 2 a, 3 a, 4 a of the cores 2, 3, 4 formed on the upper surface, and the over clad 210 that covers the surfaces of the cores 2, 3, 4 and the under cladding 200. Cores 2, 3, and 4 are formed on one surface of the underclad 200, and the refractive indexes of the underclad 200 and the overclad 210 are lower than the refractive indexes of the cores 2, 3, and 4. As an example, the refractive indexes of the cores 2, 3 and 4 are 1.4625, and the refractive indexes of the under cladding 200 and the over cladding 210 are 1.458. The dimensions of the cores 2, 3 and 4 are 100 μm × 100 μm. The underclad 200 has a thickness of 200 μm, and the overclad 210 has a thickness of 100 μm.

  On the other hand, a reinforcing plate (not shown) may be attached to the entire surface or a part of the surface opposite to the surface on which the cores 2, 3, and 4 of the underclad 200 are disposed for reinforcement. Further, a reinforcing plate (not shown) may be attached to the entire surface or a part of the surface opposite to the surface covering the cores 2, 3, 4 of the over clad 210 for reinforcement.

  The under clad 200, the cores 2, 3, 4 and the over clad 210 are preferably polymer optical waveguides made of a polymer material such as UV epoxy resin, polyimide, acrylate, or polysilane.

  Further, the optical wiring board 1 may be manufactured by using the underclad 200 as glass, quartz, or silicon, and the cores 2, 3, 4 and the overclad 210 as glass or quartz. Since glass, quartz, or silicon is a hard material, it cannot take a flexible form, but can be mounted with a minimum volume if an arrangement place in the apparatus is secured.

  Next, the shape of the cores 2, 3 and 4 will be described with reference to FIGS. FIG. 3 shows a part of the core 3 and the core 4 of FIG.

  The core 2 has a substantially linear shape from one end face of the optical wiring board 1 to the vicinity of the coupling portion 5, and is coupled to the coupling portion 5 by a lead-around curve 7 from the vicinity of the coupling portion 5.

  The core 3 has a linear structure at a predetermined distance from one end of the optical wiring board 1, and thereafter is formed by a Sin curve up to the vicinity of the coupling portion 5. The vicinity of the connecting portion 5 to the connecting portion 5 are connected by a linear structure 8 or a drawing curve.

  Similarly to the core 3, the core 4 has a linear structure with a predetermined distance from one end face of the optical wiring board 1, and thereafter is formed with a Sin curve up to the vicinity of the coupling portion 5. The vicinity of the connecting portion 5 to the connecting portion 5 are connected by a linear structure 9 or a lead curve 10. The core 4 is mainly different in that it is formed larger than the amplitude of the Sin curve of the core 3.

  Furthermore, the periodic arrangement structure of the core 3 and the core 4 is formed in the same phase (see FIG. 3 (1)) or substantially in the same phase (see FIG. 3 (2)). When the periodic arrangement structure of the core 3 and the core 4 is formed in the same phase or almost the same phase, in other words, the peaks of the core curves of the two cores 3 and 4 and the bottoms of the cores 3 and 4 are on the optical axis. By forming the orthogonal straight line 301 or the orthogonal straight line 301 and the straight line 302 in the vicinity (δ1), the core 3 and the core 4 can be arranged as close as possible so that light does not interfere with each other. The width direction W of the optical wiring board 1 can be reduced, and the optical wiring board 1 can be miniaturized.

  On the other hand, when the periodic arrangement structure of the core 3 and the core 4 is not formed in the same phase, in other words, the peaks of the core curves of the two cores 3 and 4 and the bottoms of the core curves are the optical axes. When the distance (δ2) between the straight lines 301 and 302 orthogonal to the line increases, the cores 3 and 4 intersect 310 when the core 3 and the core 4 are arranged close to each other (see FIG. 3 (3)). Since optical loss increases when the cores intersect, it is necessary to increase the interval in the width direction W of the optical wiring board 1 between the cores 3 and 4 so that the cores 3 and 4 do not intersect. For this reason, the width of the optical wiring board 1 becomes W3 wider than W (see FIG. 3 (4)).

  Here, the periods of the core 3 and the core 4 need to be the same or almost the same. If the periods are greatly different, the cores 3 and 4 cross each other. Therefore, the difference in the period must be set so that the cores 3 and 4 do not intersect within the length L of the optical wiring board 1.

  Further, the core 2 is formed in a substantially straight line, whereas the core 3 is formed in a Sin curve, so that the core 3 has a longer optical path length than the core 2. In the core 3 and the core 4, the core 4 has a larger Sin curve amplitude than the core 3, and thus the core 4 has a longer optical path length than the core 3. Therefore, the optical path length is core 2 <core 3 <core 4, and the optical path lengths of the cores 2, 3 and 4 can be easily made different.

FIG. 4 shows the configuration of the laser beam multiplexing module 400 of the present invention.
Three lasers 401, 402, and 403 having different wavelengths are mounted near one end face of the optical wiring board 1, and the wavelengths of the lasers are red (620 to 750 nm band), green (495 to 570 nm band), and blue, respectively. (450 to 495 nm band). Further, a lens 404 may be mounted between each laser 401, 402, 403 and one end face of the optical wiring board 1. A laser beam multiplexing module 400 is configured by the optical wiring board 1 and the plurality of laser light sources.

  The laser beams emitted from the lasers 401, 402, and 403 are collected by the lens 404 and are incident on the core end faces 2a, 3a, and 4a of the optical wiring board 1, and propagate through the cores 2, 3 and 4; The light is combined at the coupling unit 5 to become white light. The white light propagates through one core 6 and is output as a white light source from the core end surface 6 a formed on the other end surface of the optical wiring board 1.

  The white light source output from the laser light multiplexing module 400 can be used as a projector light source.

  According to the present invention, since the optical wiring board 1 is formed by integrating a plurality of cores on a thin plate (film shape), it is easy to handle and can be easily mounted in an optical device such as a projector. Furthermore, since the optical wiring board 1 is made of a polymer optical waveguide made of a polymer, a soft and flexible form can be taken. Therefore, when the optical wiring board 1 is wired in an optical device, handling and mounting are facilitated. .

  In addition, since the plurality of cores formed on the optical wiring board 1 have different optical path lengths (particularly, different optical path lengths from one end face of the optical wiring board 1 to the coupling portion 5), speckle noise can be reduced. Can do.

  Moreover, since at least two cores of the plurality of cores are formed with a Sin curve, the optical path length can be effectively increased with respect to the length L of the optical wiring board 1. Further, since the two cores are located on the straight line perpendicular to the optical axis or in the vicinity of the perpendicular line to each other, the light interferes with the two cores 3 and 4. It is possible to dispose them as close as possible, the width direction W1 direction at one end face of the optical wiring board 1 can be reduced, and the width W of the optical wiring board 1 can be reduced.

  In this embodiment, the core is an example of a Sin curve. However, an arc curve, a parabolic curve, a conic curve, or the like may be used as long as these curves repeat periodically.

  While the invention has been described with reference to specific embodiments for a complete and clear disclosure, the appended claims are not limited to these embodiments and are intended to be useful to those skilled in the art. Should be construed as embodying all modifications and alternative constructions properly included within the scope of the basic teachings described in.

DESCRIPTION OF SYMBOLS 1 Optical wiring board 2, 3, 4, 6 Core 2a, 3a, 4a, 6a Core end surface 5 Coupling part 200 Under clad 210 Over clad 301, 302 Straight line orthogonal to an optical axis 400 Laser light multiplexing module 401, 402, 403 Laser

Claims (7)

  A single flexible substrate, a plurality of cores formed on the flexible substrate and serving as an optical signal transmission path, a surface of the flexible substrate on which the core is disposed, and a clad covering the plurality of cores are integrally configured. In the optical wiring board thus formed, the end surfaces of the plurality of cores are disposed on one end surface side of the flexible substrate, and the plurality of cores are optically coupled in the vicinity of the other end surface side of the flexible substrate. A coupling core is formed, the end surface of the coupling core is disposed on the other end surface side of the flexible substrate, and the plurality of cores are coupled from the core end surface disposed on the one end surface side of the flexible substrate. An optical wiring board characterized by different optical path lengths to the core.   2. The optical wiring board according to claim 1, wherein at least two of the plurality of cores have a curved structure arranged periodically.   3. The optical wiring board according to claim 1, wherein the peaks of the plurality of curved structures and the bottoms of the curved structures are on a straight line orthogonal to the optical axis or in the vicinity of the orthogonal line. .   4. The optical wiring board according to claim 1, wherein the curve structure arranged periodically is a Sin curve, a circular arc curve, a parabolic curve, or a conical curve.   5. A laser beam multiplexing module comprising a plurality of lasers having different wavelengths and the optical wiring board according to claim 1, wherein the wavelength is applied to a plurality of core end surfaces disposed on one end surface side of the flexible substrate. Laser beams are input from a plurality of lasers having different wavelengths, and laser beams having different wavelengths are combined and output from the end surface of the coupling core formed on the other end surface side of the flexible substrate. Laser beam multiplexing module.   The laser beams having different wavelengths are red, green, and blue wavelengths, and the laser beams having different wavelengths are combined by the coupling core to become white light and output from the end face of the coupling core. The laser beam multiplexing module according to claim 5.   7. A projector using the laser beam multiplexing module according to claim 5 as a light source.

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