Abstract: An unmanned aircraft includes: a sensor that includes at least a microphone that generates sound data; and a processor. The processor determines quality of a target sound using the sound data generated by the microphone, obtains a positional relationship between the unmanned aircraft and a sound source of the target sound using data generated by the sensor, and controls movement of the unmanned aircraft to control a distance between the unmanned aircraft and the sound source of the target sound, in accordance with the quality of the target sound and the positional relationship.

Abstract: A plastic lens having an anti-reflecting and hard coat layer is provided. The anti-reflecting layer is formed by coating a lens with a hard coat solution containing at least one oxide sol, hardening the coated solution to give a hard coat layer and immersing the lens into an acidic or alkaline solution to dissolve the oxide particles contained in the hard coat layer so as to make the layer ununiform. The anti-reflecting effect of the formed layer is equivalent to that of a conventional anti-reflecting film consisting of three or more than three layers.

Abstract: A plastic lens having an anti-reflecting and hard coat layer is provided. The anti-reflecting layer is formed by coating a lens with a hard coat solution containing at least one oxide sol, hardening the coated solution to give a hard coat layer and immersing the lens into an acidic or alkaline solution to dissolve the oxide particles contained in the hard coat layer so as to make the layer non-uniform.The anti-reflecting effect of the formed layer is equivalent to that of a conventional anti-reflecting film consisting of at least three layers.