Mold for molding substrate, method for producing a substrate using the mold and the substrate

This invention is directed to a mold for molding a substrate comprising upper and lower mold parts, said mold being provided with one or more guide grooves in a predetermined position within the opposing internal surfaces of the upper and lower mold parts to receive one or more guide members, and being interposed between the internal surfaces at the predetermined position to maintain the vertical and horizontal alignment positions constant. A substrate having a pattern corresponding to the predetermined patterns with high precision in vertical and horizontal positions on both upper and lower sides thereof is molded by pressing simultaneously one or more of the guide members received in the guide grooves and the molding material charged in a space defined by the opposing internal surfaces.

DESCRIPTION OF THE PREFERRED EMBODIMENT Preferred embodiments of a mold for molding a substrate and a method for producing substrates using the mold according to the present invention will be described in more detail below referring to drawings. As shown in FIG. 1, a mold 30 for molding a substrate according to the present invention comprises a pair of two horizontally split sections, i.e. upper and lower mold parts 30 a and 30 b , which are used to mold a substrate having a predetermined pattern on both upper and lower sides by pressing a molding material 34 charged in a space S formed by the opposing internal surfaces of the upper and lower mold parts 30 a and 30 b , wherein such a mold for molding substrate 30 is characterized in that the upper and lower mold parts 30 a and 30 b are provided with one or more guide grooves 33 formed at a predetermined position on the opposing internal surfaces thereof to receive said one or more guide members 32 , and being interposed between the internal surfaces at the predetermined position so as to maintain the vertical and horizontal alignment positions constant for said upper and lower mold parts 30 a and 30 b , thereby a substrate having a pattern corresponding to the predetermined patterns with high precision in vertical and horizontal positions on both upper and lower sides of the substrate is molded by pressing simultaneously one or more of the guide members 32 received in said one or more guide grooves 33 and said molding material 34 charged in the space S defined by the opposing internal surfaces of the mold parts. Incidentally, when a mold for molding a substrate according to the present invention is produced, it is preferable that machining is conducted under the condition that the upper and lower mold parts 30 a and 30 b are arranged in parallel as shown in FIG. 6 to simultaneously produce the upper and lower mold parts 30 a and 30 b . One may form a mold having guide grooves 33 and reversal grooves 31 of which relative positions match each other with very high precision on the internal surfaces of the upper and lower mold parts 30 a and 30 b . Since the relative positions of the guide grooves 33 and the reversal grooves 31 of the upper and lower mold parts 30 a and 30 b match each other with very high precision, thus produced mold 30 for molding a substrate is preferable in the point that predetermined patterns (reversed configuration of reversal grooves 31 ) can be disposed on the upper and lower sides of the substrate so that the patterns corresponding to the predetermined patterns are formed with very high precision at vertical and horizontal positions. Moreover, the method for producing a substrate according to the present invention is characterized by receiving one or more guide members 32 in one or more guide grooves 33 formed on the mold 30 for molding a substrate as described in the above, charging a molding material 34 into the space S defined by the opposing internal surfaces of said upper and lower mold parts 30 a and 30 b , and, pressing simultaneously said one or more guide members 32 and the molding material 34 , thereby a substrate having predetermined patterns corresponding to an inverted profile of grooving press die 31 with high precision in vertical and horizontal positions on both upper and lower surfaces of the substrate is obtained. (See FIG. 1 ) By adopting the aforementioned configuration for the mold for molding a substrate and the method for producing substrates using such a mold, it is possible to provide a mold for molding a substrate that can form predetermined patterns with high precision using a press technique, relative positions of which patterns being made to match each other, on both upper and lower sides of a glass substrate, a ceramic substrate, etc., used for an optical fiber array and the like, as well as a method for producing a substrate using the mold. The constituent elements of this invention are explained in more detail below. As illustrated in FIG. 2 ( a ), a substrate 2 ( 21 , 22 ) molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention has on both of its surfaces predetermined patterns with a shape corresponding to the outer shape of optical fibers 1 ( 11 , 12 ), (for the illustration in FIG. 2 ( a ), patterns comprising one or more V-grooves 20 a , 20 b having almost identical shape and placement intervals), a plurality (for the illustration in FIG. 2 ( a ), two pieces) of these substrates 2 ( 21 , 22 ) placed in a lamination in such a way that each predetermined pattern (for the illustration in FIG. 2 ( a ), patterns of V-grooves 20 a , 20 b ) faces the other, and at the same time sandwiching and arranging one or more of the optical fibers 1 ( 11 , 12 ) in between each of the predetermined patterns (for the illustration in FIG. 2 ( a ), patterns of V-grooves 20 a , 20 b ) of these multiple substrates 2 ( 21 , 22 ), while maintaining their center-to-center distance between each other almost identical transverse-wise (for the illustration in FIG. 2 ( a ), between Y 1 and Y 2 ) and juxtaposition-wise (for the illustration in FIG. 2 ( a ), between X 1 and X 2 ). In this case, as illustrated in FIG. 2 ( a ), in order to improve reliability of the optical fiber array 10 comprising the substrate 2 , which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, by causing each of the elements affixed more securely, the optical fiber array 10 may be further provided with a fixing member 3 to press and affix the optical fiber 12 portion of one or more of the optical fibers 1 ( 11 , 12 ) arranged on one of the surfaces of the substrate 22 with the other side being exposed, except for the optical fiber 11 that is sandwiched and aligned in between the both surfaces of substrate 2 ( 21 , 22 ). For the optical fibers 1 ( 11 , 12 ) to be arranged and secured on the substrate 2 ( 21 , 22 ), which is molded with the mold for molding a substrate and the method for molding substrates using the mold according to the present invention, there is no specific limitation. Usually, the optical fibers 1 ( 11 , 12 ) is arranged and secured in a bare condition with its external coating removed. Concerning the size of the optical fibers 1 ( 11 , 12 ) to be arranged and secured on the substrate which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, for example, a fiber having its outer diameter of 0.125 mm and an outer diameter of its external coating between 0.25 to 0.90 mm can be mentioned. While there is no specific limitation for the material of the substrate 2 ( 21 , 22 ) which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, for example, since it is desirable to make it translucent when a UV-curable adhesive is used to affix optical fibers 1 ( 11 , 12 ) to the aforementioned fixing member 3 to be used as necessary, those comprising borosilicate glass can be mentioned as a preferred example. For the predetermined patterns with the shape corresponding to the outer shape of optical fibers 1 ( 11 , 12 ) and to be formed on both upper and lower sides of the substrate 2 ( 21 , 22 ) which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, although there is no specific limitation as long as such patterns could be formed with high precision and with the ability of sandwiching and arranging the aforementioned optical fibers 1 ( 11 , 12 ) while maintaining their center-to-center distance between each other almost identical transverse-wise (between Y 1 and Y 2 ) and juxtaposition-wise (between X 1 and X 2 ) and having almost identical shape and placement intervals with the optical fibers 1 ( 11 , 12 ), a pattern with the V-grooves 20 a , 20 b is preferred since it enables the optical fibers 1 ( 11 , 12 ) to be securely supported at three points. As examples of the placement intervals for the V-grooves 20 a , 20 b , they may be arranged in such a way that the optical fibers 1 ( 11 , 12 ) can be separated with a specific distance between them as illustrated in FIG. 2 ( a ), or alternatively, they may be arranged tightly so that the optical fibers 1 ( 11 , 12 ) could be in contact with each other although the latter is not illustrated. As another example of the placement intervals for the V-grooves 20 a , 20 b , they may be arranged with a half-pitch shift between the two sides of the substrate 2 ( 21 , 22 ), as illustrated in FIG. 2 ( c ). Configuring them in this manner enables the optical fibers 1 ( 11 , 12 ) to be arranged in a two-dimensional zigzag fashion to diversify the arrangement pattern. For the fixing member 3 to be used as necessary in the optical fiber array 10 using the substrate 2 , which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, although there is no specific limitation as long as it is capable of pressing and securely affixing the optical fibers 1 ( 11 , 12 ) arranged on top of the substrate 2 ( 21 , 22 ) against the substrate 2 ( 21 , 22 ), since it is desirable to make it translucent when a UV-curable adhesive is used to affix optical fibers 1 ( 11 , 12 ) to the substrate 2 ( 21 , 22 ), those comprising borosilicate glass can be mentioned as a preferred example. For the method of affixing the optical fibers 1 ( 11 , 12 ) arranged on top of the substrate 2 ( 21 , 22 ), which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, onto the substrate 2 ( 21 , 22 ), a method can be mentioned by way of an example wherein the optical fibers 1 ( 11 , 12 ) are first affixed provisionally with an adhesive agent onto the predetermined pattern, for example V-grooves 20 a , 20 b , that are formed on the substrate 2 ( 21 , 22 ), after which the fixing member 3 is affixed and, finally, the substrate 2 ( 21 , 22 ), a cylindrical member 4 as described later, and the fixing member 3 are affixed permanently. As illustrated in FIG. 3 ( a ) and its partially enlarged view, FIG. 3 ( b ), an optical fiber array comprising the substrate 2 , which is molded with the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, may also comprise the optical fiber 1 arranged for example on V-grooves on the substrate 2 , in a condition where it is inserted and encased in a cylindrical member 4 comprising, typically, borosilicate glass and having a through hole 4 a , while maintaining their transverse and juxtaposing center-to-center distances almost identical between them. Since an optical fiber array configured as described above enables provision of high precision predetermined patterns, typically V-grooves, on both sides of a substrate with almost identical shapes and placement intervals, and as it also enables more accurate and simplified positioning of optical fibers on a substrate, the transverse and juxtaposing center-to-center distances between each of a multiple number of optical fibers aligned two dimensionally and laminated on the substrate can be accurately set. While there is no specific limitation with regard to the material for the mold for molding a substrate according to the present invention, from the standpoint of heat resistance at high temperatures, for example, tungsten carbide (WC), various types of ceramics, or others are preferred. Concerning the material for the guide member 32 , as shown in FIG. 1 , used in the mold for molding a substrate and the method for producing substrates using the mold according to the present invention, borosilicate glass is preferred as in the case of the forming material 34 that becomes a substrate after molding. Furthermore, concerning the guide member 32 , its viscosity at the molding temperature is preferably equal to or higher than the viscosity of the molding material 34 at the molding temperature. If the viscosity of the guide member 32 at the molding temperature is lower than the viscosity of the molding material 34 at the molding temperature, the guide member 32 will collapse prior to the pressing, making it impossible to thoroughly demonstrate the functionality of maintaining the transversal distance constant between the opposing internal surfaces (for the illustration in FIG. 1 , between L 1 and L 2 ). As described in the above, the present invention enables provision of a mold for molding a substrate that can form predetermined patterns with high precision using a press technique (e.g., a glass-press and a ceramic powder molding), relative positions of these patterns being made to match each other, on both upper and lower sides of a glass substrate, a ceramic substrate, etc., used for an optical fiber array and the like, a method for producing a substrate using the mold, and the substrate.