Light touch apparatus

A projection light touch apparatus, comprising:

• a light emitting unit, emitting a projection light ray;
• an imaging unit, capturing an external image, wherein the external image comprises multiple two-dimensional pixels, and corresponding to relative positions of the two-dimensional pixels, the projection light ray of the light emitting unit forms multiple projection spots;
• an optical signal processing unit, electrically connected to the imaging unit, and receiving multiple pieces of reflection light information, wherein the pieces of reflection light information are respectively reflected from the projection spots, and the optical signal processing unit can further analyze the pieces of reflection light information to correspondingly generate multiple pieces of analysis spot information, wherein the pieces of analysis spot information comprise at least one piece of touch vibration information, and the at least one piece of touch vibration information comprises a touch vibration wave whose frequency domain is different from a frequency domain of the projection light ray;
• and
• a position processing unit, electrically connected to the optical signal processing unit, wherein the position processing unit receives the at least one piece of touch vibration information, and the position processing unit calculates a touch position according to the at least one piece of touch vibration information, wherein the touch position is a relative epicenter position at which the touch vibration wave is generated.