Abstract: A dome cover (6) is manufactured by injection molding by steps of: forming a cavity (14) having the shape of the dome cover (6) between an upper mold (12) and a lower mold (13) for an injection molding die (11), providing a gate port (16) for injecting melt resin at a position (of the upper mold (12)) corresponding to the zenithal portion (15) of the dome cover (6), and injecting the melt resin into the cavity (14) through the gate port (16). The resin injected from the center portion (the portion corresponding to the zenithal portion (15) of the dome cover (6)) of the cavity (14) flows uniformly toward the circumference of the cavity (14). Therefore, variations in pressure and temperature of the resin in the cavity (14) are restrained and, consequently, molding irregularity of the manufactured dome cover (6) is restrained. According to the method of manufacturing the dome cover as described above, generation of the partial molding irregularity on the manufactured dome cover is restrained.

Abstract: A variable focal lens which does not require a reduction of a zoom factor and eliminates an origin sensor is provided. A microcomputer 15 functions as a focus adjustment section which controls a stepper motor 13 to move a focusing ring 5 for a focus adjustment. The microcomputer 15 causes the focusing ring 5 to move by a first moving distance in a first moving direction toward one of a FAR side and a NEAR side, and then to move the focusing ring 5 by a second moving distance in a second moving direction opposite to the first moving direction, and set the point where the focusing ring reaches after the movement in the second moving direction as a reference point for adjustment, and the microcomputer 15 causes the focusing ring 5 to move from the reference point for adjustment in the first moving direction within a range equal to or less than the second moving distance to carry out the focus adjustment.

Abstract: A dome cover (6) is manufactured by injection molding by steps of: forming a cavity (14) having the shape of the dome cover (6) between an upper mold (12) and a lower mold (13) for an injection molding die (11), providing a gate port (16) for injecting melt resin at a position (of the upper mold (12)) corresponding to the zenithal portion (15) of the dome cover (6), and injecting the melt resin into the cavity (14) through the gate port (16). The resin injected from the center portion (the portion corresponding to the zenithal portion (15) of the dome cover (6)) of the cavity (14) flows uniformly toward the circumference of the cavity (14). Therefore, variations in pressure and temperature of the resin in the cavity (14) are restrained and, consequently, molding irregularity of the manufactured dome cover (6) is restrained. According to the method of manufacturing the dome cover as described above, generation of the partial molding irregularity on the manufactured dome cover is restrained.

Abstract: A variable focal lens which does not require a reduction of a zoom factor and eliminates an origin sensor is provided. A microcomputer 15 functions as a focus adjustment section which controls a stepper motor 13 to move a focusing ring 5 for a focus adjustment. The microcomputer 15 causes the focusing ring 5 to move by a first moving distance in a first moving direction toward one of a FAR side and a NEAR side, and then to move the focusing ring 5 by a second moving distance in a second moving direction opposite to the first moving direction, and set the point where the focusing ring reaches after the movement in the second moving direction as a reference point for adjustment, and the microcomputer 15 causes the focusing ring 5 to move from the reference point for adjustment in the first moving direction within a range equal to or less than the second moving distance to carry out the focus adjustment.