The invention provides compounds of formula 1Wherein R1, R2, R3, R4, R5, R6a, R6b, R6c, R6d, R6e and R7 are defined in the specification. A remainder of the rod is left untreated so as to minimize impact on taste and burn characteristics of the cigarette. An FPC interposed between an optical unit and the solid-state imaging device is formed with an opening for exposing the cover glass and an assembly reference surface of the solid-state imaging device. At least one simple filter object is generated based on a user input. For this purpose, the direction of rotation of the belt shaft is detected and, depending on the direction of rotation as detected, the electric current supplied to the electric motor is changed from a first value to a second value that is different from the first value by an amount required to compensate for hysteresis.