El backlight with the keyboard features: the application of light at night or dark environment relatively long time job, be able to clear a long time to language, design, the keyboard is displayed.

The steel structure is getting more and more application because of its light weight, big span , short time limit for a project, various styles , easy to protect the environment and so on.

The application only needs to project one face-shaped light spot pattern and only needs one-time imaging so as to finish the measurement of the space coordinates of all the light spots on the face.