Abstract:
An optical function module comprises a collimator block having a substrate, at least two collimators disposed on the substrate in confronting relation to one another for collimating a light flux directed along a preselected path between the collimators, and support members each for supporting a respective one of the collimators on the substrate. An optical function device is removably connected by a connecting structure to the collimator block so that the optical function device is positioned along the preselected path of the light flux between the collimators.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical functional module on which is mounted an optical functional device such as an attenuator device, a shutter device, or a switching device for attenuating or interrupting an optical signal used in optical communication or the like, or for switching between paths for optical signals. 
     2. Description of the Related Art 
     In an optical network using optical fibers and used for the Internet or the like, there is a need to perform attenuation or interruption of optical signals, switching of signal paths, etc., in a repeater. Various optical functional components such as attenuators, shutter devices and switching devices having corresponding functions are therefore used. 
     Enlargement of a relay station becomes a problem due to the increase of a necessary number of relay devices in accordance with the recent increase in traffic of information communication such as optical communication. 
     Therefore, there is a demand that these optical functional parts be miniaturized into a module to thereby miniaturize the relaying equipment. 
     These modularized optical functional parts and compact optical function modules composed of collimator blocks provided with collimators sending/receiving optical signals as parallel light beam flux have been used in the relay station for the optical communication network or the like. 
     FIGS. 7A and 7B show a conventional example of an optical function module. FIG. 7A is a plan view of the conventional optical function module  200 . FIG. 7B is a front view of the conventional optical function module  200  shown in FIG.  7 A. 
     The conventional optical function module  200  is composed of collimators  101  and  101 ′ and a collimator support member  203  holding and facing the collimators  101  and  101 ′ disposed on a substrate  204 . The collimators are connected to optical cables  102  and  102 ′, respectively. 
     An optical signal passes through the optical cable  102  and is sent from the collimator  101  as a parallel optical beam flux toward the confronting collimator  101 ′. Thus, a light flux  106  is formed passing through a space between the confronting collimators  101  and  101 ′. 
     The optical functional part  124  is disposed directly on the substrate  204  whereby the optical functional part  124  exhibits its function to the light flux  106 . Also, three or more collimators are provided on the collimator support member  203  and a switching device is used as the optical functional part  124  to thereby make it possible to perform the switching of paths of optical signals. 
     The important aspect of this conventional optical function module is the position of the optical functional part on the substrate. 
     In order to perform the attenuation, interruption and path change of the optical signals, the optical signal that has passed through the optical cable is sent as a parallel light beam flux by the collimator having an integral structure of a fiber and a lens, and the optical functional part is caused to come into contact with this parallel light beam flux to thereby perform the attenuation, interruption and path change of the optical signal. 
     However, a diameter of the light flux is about 500 μm, for example. In addition, the optical functional part is a very compact part. For this reason, in order to cause the optical functional part to come into exact contact with the light flux and to exhibit its function, even if there is a very slight shift with respect to the light flux in direction and position of the optical functional part, the function of the optical function module is impaired. In order to prevent this shift, whenever the optical functional part is to be mounted on the substrate, it is necessary to perform the mounting operation while measuring the exact position and direction. This causes the increase of the load on manufactures largely in terms of the cost and working efficiency. 
     Also, the mounting operation of the optical functional part is performed by means of fastening means such as welding, adhesives and screws. 
     However, for example, in the case of using the welding for mounting, it is very difficult to perform the welding operation under the condition for keeping the optical functional part at the suitable position and level for a long period of time. Also, there is a fear that the substrate would expand or shrink by the heat generated upon the welding operation so that an error would occur in position and direction of the optical functional part. Also, in order to prevent the damage of the optical functional part due to the heat, there is a limit to the area to be welded. Thus, there is a fear that a shift may occur due to the lack of the adhesive strength. 
     On the other hand, in case of the mounting operation with adhesives, it is possible to resolve the above-described problem of the heat generated by the welding but in order to prevent the occurrence of the error, there is a problem in that the optical functional part is required to be kept in the suitable position and direction for a long period of time until the adhesives completely dries. 
     Furthermore, in the conventional case, as described above, the optical functional part is mounted directly on the substrate. If any problem supposedly occurs irrespective of the error in the position and direction of the optical functional part and the fault of the function thereof, in the case where the mounting operation is performed by welding or with the adhesives, it is difficult to readjust the position and direction of the optical functional part and exchange of the optical functional parts. 
     Also, in case of the mounting operation by screws, it is possible to change the optical functional parts. In case of the readjustment, although it is possible to provide a new screw hole in a place far from the existing screw hole, in the readjustment of the very short distance and direction, it is impossible to provide any new screw hole due to the hindrance of the existing screwhole. It is therefore difficult to perform the readjustment. 
     In view of the above, it is very difficult to reuse each part such as an optical functional part and a substrate in the conventional optical function module. There is a problem in terms of a cost or a maintaining property. 
     SUMMARY OF THE INVENTION 
     In view of such circumstances, an object of the present invention is to provide an optical function module in which an optical functional part may be rapidly and easily disposed in a position where the function thereof exhibits exactly and the parts are readily replaced and may be reused. 
     Aspects of the present invention will be described here in after. 
     A first aspect of the present invention relates to an optical function module, characterized by comprising: a collimator block including a substrate, at least two or more facing collimators disposed on the substrate, and at least two collimator support members for supporting the collimators; and an optical functional part unit including an optical functional part to be disposed on the collimator block and an arrangement means for arranging the optical functional part on the collimator block. 
     According to a second aspect of the present invention, in the first aspect of the invention, an optical function module is characterized in that the arrangement means comprises a recess portion provided in the substrate and a holder base engaged exactly with the recess portion for arranging the optical functional part in a position where the optical functional part exactly works on a light flux between the collimators. 
     According to a third aspect of the present invention, in the first or second aspect of the invention, an optical function module is characterized in that the arrangement means comprises at least one guide pin provided on the substrate and a guide pin insertion hole corresponding to the guide pin, and a holder base for engaging the guide pin and the guide pin insertion hole with each other to dispose the optical functional part to a position where the optical functional part exactly works on a light flux between the collimators. 
     According to a fourth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that the optical functional part is an optical filter device for obtaining a transmission light having a predetermined wavelength from a light flux between the collimators. 
     According to a fifth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that the optical functional part is a shutter device for interrupting a light flux between the collimators. 
     According to a sixth aspect of the present invention, in any one of the first to third aspects of the invention, an optical function module is characterized in that an optical functional part is an attenuating device for attenuating a light flux between the collimators. 
     According to a seventh aspect of the present invention, in any one of the first to sixth aspects of the invention, an optical function module is characterized in that the optical functional part is provided with a piezoelectric actuator using as a power source a vibration generated in a piezoelectric vibrating member as a driving source. 
     According to an eighth aspect of the present invention, in any one of the first to seventh aspects of the invention, an optical function module is characterized in that the substrate, the collimator support member, the holder base and the arrangement means are made of stainless steel. 
     According to a ninth aspect of the present invention, in any one of the first to eighth aspects of the invention, an optical function module is characterized in that the substrate, the collimator support member, the holder base and the arrangement means are made of super engineering plastics. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
     FIG. 1 is a view showing a primary structure of an optical function module in accordance with a first embodiment of the present invention; 
     FIG. 2A is a plan view of the collimator block in accordance with the first embodiment of the present invention, FIG. 2B is a sectional front view of the collimator block taken along the line E-E′ of FIG. 2A, and FIG. 2C is a side elevational view of the collimator block shown in FIG. 2A; 
     FIG. 3A is a plan view of a holder base in accordance with the first embodiment of the present invention, and FIG. 3B is a cross-sectional view of the holder base taken along the line F-F′ of FIG. 3A; 
     FIG. 4A is a plan view of the optical function module provided with an optical filter device in accordance with the first embodiment of the present invention, FIG. 4B is a sectional front view of the optical function module taken along the line G-G′ of FIG. 4A, and FIG. 4C is a sectional side elevational view of the optical function module taken along the line H-H′ of FIG. 4A; 
     FIG. 5A is a plan view of the optical function module in accordance with a second embodiment of the present invention, FIG. 5B is a sectional front view of the optical function module taken along the line I-I′ of FIG. 5A, and FIG. 5C is a sectional side elevational view of the optical function module taken along the line J-J′ of FIG. 5A; 
     FIG. 6A is a plan view of the optical function module in accordance with a third embodiment of the present invention, FIG. 6B is a sectional front view of the optical function module taken along the line K-K′ of FIG. 6A, and FIG. 6C is a sectional side elevational view of the optical function module taken along the line L-L′ of FIG. 6A; and 
     FIG. 7A is a plan view of the conventional optical function module, and FIG. 7B is a front view of the conventional optical function module shown in FIG.  7 A. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     An optical function module according to the present invention will now be described with reference to the accompanying drawings. 
     The following embodiments are described only for the purpose of describing the present invention and are not used to limit the scope of the invention. Accordingly, it is possible for those skilled in the art to adopt various embodiments or forms including part or all of these elements. These modifications and alternative forms should be included in the scope of the invention. 
     First Embodiment 
     FIG. 1 is a view showing a primary structure of an optical function module in accordance with a first embodiment of the present invention. 
     The optical function module  100  according to the first embodiment of the present invention is composed of a collimator block  107  and an optical functional unit  122  (hereinafter “optical functional part unit”) to be mounted on the collimator block  107 . 
     The collimator block  107  is composed of a substrate  104 , collimators  101  and  101 ′ disposed on the substrate  104  and collimator support members  103  and  103 ′ facing and holding the collimators  101  and  101 ′ and is connected to optical cables  102  and  102 ′. 
     The optical function part unit  122  is provided with an optical function device or optical functional part  124  and mounting means  105  (hereinafter “arrangement” means) for mounting the optical functional part  124  to the collimator block  107 . 
     An optical signal passes through the optical cable  102  and fed from the collimator  101  as a parallel light beam flux toward the confronting collimator  101 ′. Thus, a light flux  106  passing through a space between the confronting collimators  101  and  101 ′ is formed. The optical functional part  124  works on this light flux  106 . 
     The optical functional part  124  includes, for example, an optical filter device for obtaining a transmission light having a predetermined wavelength from the optical signal, an attenuating device for attenuating the optical signal, a shutter device for shutting the optical signal and the like. 
     Also, it is possible to provide three or more collimators on the substrate  104  and to arrange two or more collimators at positions facing the single collimator to use a switching device utilizing the optical refraction as the optical functional part to thereby switch the paths of the optical signal. In addition, it is also possible to arrange a plurality of collimators at positions facing a plurality of collimators like the arrangement of the three collimators at positions facing the two collimators. 
     In the same manner as in the above-mentioned conventional optical function module, the optical functional part  124  should be arranged at the position where it works exactly on the light flux  106 . The means for easily and rapidly performing this is the arrangement means  105 . 
     This arrangement means  105  is composed of a recess portion provided on the substrate  104 , guide pins, a base member or holder base for engaging the recess portion and having guide pin insertion holes for receiving the guide pins. 
     The recess portion provided on the substrate  104  and the guide pins will be described in detail with reference to FIGS. 2A to  2 C. The holder base  123  engaging with the recess portion and the guide pin insertion holes will be described in detail with reference to FIGS. 3A and 3B. 
     FIG. 2A is a plan view of the collimator block  107  in accordance with the first embodiment of the present invention. FIG. 2B is a sectional front view of the collimator block  107  taken along the line E-E′ of FIG.  2 A. FIG. 2C is a side elevational view of the collimator block  107  shown in FIG.  2 A. 
     The collimator block  107  in accordance with the first embodiment of the present invention is provided with the arrangement means  105  and a cover mounting screw holes  118  in addition to the substrate  104 , the collimators  101  and  101 ′, the collimator support members  103  and  103 ′ for supporting the collimator  101  and  101 ′ and the optical cable  102  and  102 ′. 
     The arrangement means  105  provided on the substrate  104  is provided with a square recess portion  125 , guide pins  116  to be provided on this square recess portion  125  and fastening screw holes  113  passing up and down through the substrate. 
     Furthermore, a square hole  126  passing through the recess portion  125  is provided in the recess portion  125 . 
     In order to cause the light flux  106  to pass between the collimators  101  and  101 ′ normally, the collimator support members  103  and  103 ′ for supporting the collimators  101  and  101 ′, respectively, are subjected to the exact positional adjustment so that their positions and directions are completely identical with each other. 
     The recess portion  125  is exactly machined so that sides A and C are parallel with the optical axis of the light flux  106 . Also, sides B and D are exactly machined so as to be perpendicular to the optical axis of the light flux  106 . Also, upon this machining operation, the distance between the side A and the light flux  106  and the distance between the side C and the light flux  106  are measured. 
     Furthermore, the distance between the side B and the side D, i.e., the length of the light flux is measured. The recess portion  125  thus machined functions as a positional standard for the optical functional part  124  (FIG.  1 ). 
     The two guide pins  116  are provided in the positions where the line connecting the two guide pins to each other is identified with the optical axis of the light flux  106  without any error so that these pins also function as the positional standard for the optical functional part  124 . 
     Note that, in this embodiment, there is shown the case where the two guide pins  116  are provided. However, the invention is not limited to this case. For example, four guide pins may be arranged so as to form the two standard lines in parallel with the optical axis of the light flux  106  to thereby define the positional standard for the optical functional part  124 . 
     FIG. 3A is a plan view of the holder base  123  in accordance with the first embodiment of the present invention. FIG. 3B is a cross-sectional view of the holder base  123  taken along the line F-F′ of FIG.  3 A. 
     The holder base  123  in accordance with the first embodiment of the present invention is engaged with the recess portion  125  (FIGS. 2A and 2B) on the substrate  104  as the fastening means. Also, the holder base  123  is provided with the guide pin insertion holes  117  passing up and down through the holder base  123  exactly corresponding to the guide pins  116  of FIGS. 2A to  2 C. 
     Furthermore, the holder base  123  is provided with fastening screw holes  114  passing up and down through the holder base  123  corresponding to the fastening screw holes  113  in the recess portion  125  shown in FIGS. 2A and 2B and fastening screws  115  corresponding to the fastening screw holes  113  and  114 . 
     The holder base  123  is formed into a square shape and perfectly identified with the recess portion  125  shown in FIGS. 2A and 2B in shape and dimension. Accordingly, the holder base  123  also functions as the positional standard for the optical functional part  124  provided on the above-described recess portion  125 . 
     Note that, in order to easily perform the engagement of the holder base  123  with the recess portion  125  and the removal of the base from the recess portion  125 , the corner portions of the holder base  123  are beveled to such an extent that the perfect identification of the holder base  123  with the recess portion  125  in the dimension and the shape may be kept. 
     Also, since the guide pin insertion holes  117  exactly correspond to the guide pins of FIGS. 2A to  2 C as described above, the holder base  123  provided with these pins function as the positional standard for the optical functional part  124  provided by the above-described guide pins  116 . 
     It is possible to obtain the design path  108  for the light flux  106  from the above-described standard. After that, the holder base  123  is engaged with the recess portion  125  (FIGS.  2 A and  2 B). When the optical function module  100  is actually used, the light flux  106  passes through the design path  108 . 
     The optical functional part insertion hole  109  is provided in the position defined by using the design path  108  on the holder base  123  as the standard. The optical functional part  124  is inserted into this optical functional part insertion hole  109  to be arranged in place. 
     The arranged optical functional part  124  is fastened by means of a fastening screw hole  111  passing through the holder base  123  upwardly and reaching the bottom portion of the optical functional part  124  and a corresponding fastening screw  112 . 
     The holder base  123  to which the optical functional part  124  is fixed is engaged with the recess portion  125  so that the optical functional part  124  may easily and rapidly be arranged, without any adjustment work, to the position where it serves normally with respect to the light flux  106 . 
     The above-described arrangement means  105  is used to enhance the exchangeability of the parts. In the case where a plurality of different kinds of optical functional parts  124  are used differently on the single collimator block  107  as necessary, and in the case where the broken optical functional part  124  is to be exchanged by a new one, the optical functional part unit  122  where the optical functional parts  124  are arranged respectively is exchanged as a unit whereby it is possible to perform the exchange of the optical functional parts  124  easily and rapidly without any adjustment work in position and direction. 
     FIG. 4A is a plan view of the optical function module  100  provided with an optical filter device in accordance with the first embodiment of the present invention. FIG. 4B is a sectional front view of the optical function module  100  taken along the line G-G′ of FIG.  4 A. FIG. 4C is a sectional side elevational view of the optical function module  100  taken along the line H-H′ of FIG.  4 A. 
     FIGS. 4A to  4 C show the optical function module  100  provided with an optical filter device  127  as the optical functional part  124  in accordance with the first embodiment of the present invention. 
     The optical function module  100  is further provided with a cover  121 , for covering the overall optical function module, to be mounted by means of cover mounting screws  119  corresponding to cover mounting screw holes  118  to be provided in the collimator support members  103  and  103 ′. 
     The optical filter device  127  is a device for obtaining the transmission light having a predetermined wavelength from the light flux  106  by means of a transmission light filter member  128 . 
     As shown in FIG. 4B, the transmission light filter member  128  is rotated about its own rotary axis and brought into contact with the light flux  106  to thereby obtain the transmission light having a predetermined wavelength. 
     The optical filter device  127  is exactly arranged by means of the arrangement means  105  in the position where it normally works on the light flux  106 , i.e., the position where the transmission light filter member  128  is brought into suitable contact with the light flux  106 . 
     Also, in the case where the transmission light wavelength is not necessary, the transmission light filter member  128  is rotated to the position where it is out of contact with the light flux  106 . 
     In order not to generate rust for a long period of time, stainless steel, for example, SUS304, 312, 316 or the like is preferably used for the collimator support members  103  and  103 ′, the substrate  104 , the arrangement means  105 , the cover mounting screws  119 , the cover  121  and the holder base  123 . 
     In order to prevent the expansion due to the heat, it is possible to use super engineering plastics for the collimator support members  103  and  103 ′, the substrate  104 , the arrangement means  105 , the cover mounting screws  119 , the cover  121  and the holder base  123 . 
     The super engineering plastics have a much lower thermal expansion coefficient than that of conventional engineering plastics and are less expanded due to the heat. The thermal expansion coefficient of PEEK (polyether etherketone) that is one of the typical super engineering plastics is 2.3×10 −5 /K at 200C. and is smaller than 2.7×10 −5 /K of PC (polycarbonate) which is one of the conventional engineering plastics. 
     Second Embodiment 
     FIG. 5A is a plan view of the optical function module  100  in accordance with a second embodiment of the present invention. 
     FIG. 5B is a sectional front view of the optical function module  100  taken along the line I-I′ of FIG.  5 A. 
     FIG. 5C is a sectional side elevational view of the optical function module  100  taken along the line J-J′ of FIG.  5 A. 
     FIGS. 5A to  5 C show the optical function module  100  provided with a shutter device  129  as the optical functional part  124  in accordance with the second embodiment of the present invention. 
     The shutter device  129  is a device for shielding the light flux  106  by means of a shutter member  130 . 
     As shown in FIG. 5B, the shutter member  130  is rotated about its own rotary axis to interrupt the light flux  106 . 
     The shutter device  129  is exactly disposed by the arrangement means  105  in the position where it works normally on the light flux  106 , i.e., the shutter member  130  suitably interrupts the light flux  106 . 
     Also, in the case where the light flux is not to be interrupted, the shutter member  130  is rotated to the position where it no longer contacts the light flux  106 . 
     The other factors such as shape, function, effect and the like of the member are the same as those of the optical function module of the first embodiment of the present invention. 
     Third Embodiment 
     FIG. 6A is a plan view of the optical function module  100  in accordance with a third embodiment of the present invention. 
     FIG. 6B is a sectional front view of the optical function module  100  taken along the line K-K′ of FIG.  6 A. 
     FIG. 6C is a sectional side elevational view of the optical function module  100  taken along the line L-L′ of FIG.  6 A. 
     FIGS. 6A to  6 C show the optical function module  100  provided with an attenuating device  131  as the optical functional part  124  in accordance with the third embodiment of the present invention. 
     The attenuating device  131  is a device for attenuating the light flux  106  by means of a variable attenuating member  132 . 
     As shown in FIG. 6B, the variable attenuating device  132  is rotated about its own rotary axis and is brought into contact with the light flux  106  to thereby attenuate the light flux and changes the contact area to thereby change the attenuation amount. 
     The attenuating device  131  is exactly disposed by the arrangement means  105  in the position where it normally works on the light flux  106 , i.e., the variable attenuating member  132  is brought into suitable contact with the light flux  106 . 
     Also, in the case where the attenuation is unnecessary, the variable attenuating member  132  is rotated to the position out of contact with the light flux  106 . 
     The other factors such as shape, function, effect and the like of the member are the same as those of the optical function modules of the first and second embodiments of the present invention. 
     Also, the optical function module  100  in accordance with the first to third embodiments shown in FIGS. 1A to  5 C is provided as the arrangement means  105  with both the guide pins  116  and the guide pin insertion holes  117 , and the holder base  123  and the recess portion  125 . However, the invention is not limited thereto. It is possible to only use one of the unit of the guide pins  116  and the guide pin insertion holes and the unit of the holder base  123  and the recess-portion  125 . 
     Also, the optical functional parts  124  including the optical filter device  127 , the shutter device  129  and the attenuating device  131  in accordance with the first, second and third embodiments of the present invention shown in FIGS. 1A to  5 C may use a piezoelectric actuator using as a power source the vibration generated in a piezoelectric vibrating member as a driving source. Thus, it is possible to further miniaturize the optical function module  100 . 
     Moreover, an ultrasonic wave motor using as a driving source the mechanical vibration in the ultrasonic wave band may be included in this piezoelectric actuator. 
     Moreover, an encoder (not shown) for measuring an angular velocity is provided to thereby make it possible to perform the further fine operation. 
     As described above, according to the present invention, it is possible to exactly dispose to a predetermined position of the collimator block an optical functional part unit provided with an optical functional part and an arrangement means capable of exactly positioning this optical functional part which is disposed exactly to a predetermined position to the substrate. Thus, it is possible to provide an optical function module in which an optical functional part may easily and rapidly be displaced in a position where the optical functional part work exactly and parts can be exchanged and reused.