Abstract: The present invention provides a method for adjusting the sensitivity of an acceleration detecting device comprising a pair of piezoelectric elements, of an acceleration sensor device for detecting an externally acting acceleration. According to this method, electric charges produced in the pair of piezoelectric elements placed at positions being symmetric with respect to a weight are made to be equal to each other. The electric outputs of the piezoelectric elements are changed by varying the electrostatic capacity of the acceleration sensor device. Thus, noise sensitivity is suppressed.

Abstract: The present invention provides a method for calibrating the sensitivity of an acceleration sensor device, which can suppress the sensitivity thereof in the direction of each of orthogonal axes other than that thereof in the direction of an orthogonal axis to be measured. This method is performed so as to calibrate the sensitivity of an acceleration sensor device which detects an acceleration by using an acceleration detecting device comprising a pair of piezoelectric elements. According to this method, when oscillations are applied to the acceleration sensor device, the absolute values of electrical outputs of the piezoelectric elements of the pair are brought close to each other by applying a voltage of a polarity, which is opposite to the polarity of polarization being already present therein, to the piezoelectric element, whose electric output has an absolute value larger than the absolute value of the electric output of the other piezoelectric element of the pair.

Abstract: On the pressing surface of a die, a first protrusion having a substantially triangular cross section and a second protrusion having a length which is greater than a width thereof and a substantially trapezoidal cross section in planes extending through both length and width dimensions thereof are provided. By press forming, a groove with a substantially V-shaped cross section to mount an optical part, and a groove with a substantially inverse-trapezoidal cross section providing an alignment marking are formed, being inverse-transferred in correspondence with the respective protrusions on one principal surface of a glass substrate. Forming such a pattern on a glass substrate produced with a die enables alignment of the glass substrate with a mask for photolithography with high accuracy.

Abstract: To provide a press mold for molding glass that is relatively less expansible than a mold material. The mold is configured so that the content volume of the mold is approximately equal to the volume of molded glass at the time of press molding, and a side face member of the mold is divided into a plurality of pieces so as to be capable of moving toward an outside but incapable of moving toward an inside. Thereby, over-tightening of mold side face can be prevented effectively, and a satisfactory molding operation can be performed by transmitting a molding pressure uniformly to a molded member without opening any mold side face.

Abstract: A heat-fused unitary ferrule includes a first glass substrate and a second glass substrate. The first glass substrate and the second glass substrate are unitarily joined by heat-fusion. A method for producing a heat-fused unitary ferrule includes the steps of: bringing a surface to be heat-fused of the first glass substrate having a groove for fixing an optical fiber into contact with a surface to be heat-fused of the second glass substrate; and subjecting the first and second glass substrates to heat-fusion at a temperature ranging from (Tg1-100).degree. C. to (Tg2+150).degree. C. (Tg1 denotes the higher glass transition temperature, and Tg2 denotes the lower glass transition temperature of the first and second glass substrates).