Patent ID: 7786368

Claim:
An actuator unit for a performance operator member comprising: a performance operator drive device including a plunger that mechanically drives the performance operator member; an optical density pattern provided on said plunger and having a pattern where a density gradually varies along a moving direction of said plunger so that an amount of light reflection or light transmission gradually varies in accordance with movement of said plunger, said optical density pattern being provided on a side surface of the plunger and located in a space between the side surface and a casing of the plunger; an optical sensor that irradiates light toward said optical density pattern and receives light reflected from or transmitted through said optical density pattern, and a velocity detector that detects a moving velocity of said plunger, and wherein said velocity detector is constructed separately from said optical sensor, said velocity detector being also constructed to acquire velocity information directly without acquiring position information, wherein one of said optical density pattern and said optical sensor is provided to move in interlocked relation to said plunger, and the amount of the reflected light or transmitted light, based on said optical density pattern, is detected by said optical sensor, so that a moving position of said plunger is detected on the basis of the detected amount of the reflected light or transmitted light, and wherein said optical density pattern is provided on a detected member that is mounted on said plunger, and said optical density pattern moves together with said plunger, wherein said optical sensor is fixedly provided in a predetermined position, wherein said velocity detector includes a sensor section fixedly provided in a predetermined position, and said sensor section provides an output corresponding to the moving velocity of said plunger, and wherein said optical sensor and said sensor section of said velocity detector are provided as a unit in predetermined positional arrangement.