An X-ray collimator formed of stacked laminated layers with apertures therein aligned to form complex 3-dimensional collimator structures, and method of fabrication thereof, is presented. If an error is detected in a torque sensor, the motor is driven based on the rotor rotation angle detected by a resolver and assist characteristics. The impregnating agent may be a natural or synthetic lubricant, a plastic or, more commonly, a molten metal or metal alloy. , phase current of a motor-generator exceeds a permissible value, in a high rotational speed region, the electronic control unit performs control for shifting up an automatic transmission provided between the motor-generator and driving wheels, or control for bringing the transmission into a released state, so as to reduce the rotational speed of the motor-generator. The LED driver current can be regulated by changing the low and high threshold voltages of the capacitor pump controller, thereby to control the optical intensity of the LED.