1. Subjects slept at home, and compliance was confirmed with a wrist actigraph and a photosensor.

2. The film obtained through the method has good application prospect in flat display, photosensor, in particular near infrared sensor, solar cell and other fields.

3. The tester adopts electronic auto loading, computer software programming, high power optical measurement, photosensor and other systems.

4. In one embodiment, apparatus is provided with a light source, an optic element, at least one photosensor , and a control system.

5. The control system is operably associated with both the photosensor and the light source, to regulate the light source's light output in accordance with measurements received from the photosensor.

6. The article touches upon the principle of displacement measuring system consisting of diode laser focusing lens, reflecting main scale grating, quarternary index scale grating photosensor.