Operational prnciple of photoswitch
The principle of photoswitch: the projector will ju dge and react on the basis of light beam from the
projector which is interdicted by object or emitted partly.
Explanation of type
Through-beam type
Through-beam type photoelectric switch is designed that via the light beam between
opposite-mounted transmitter and receiver; the object passing through these two devices will
interrupt the light beam and start the receiver. (Fig R1)
Diffuse type
Diffuse reflection type photoelectric switch integrates the transmitter and the receiver. Light
reflected by the photoelectric switch is reflected back to the receiver by the detected object.
(Fig.R2)
Retro reflective type
Retro reflective type photoelectric switch also integrates the transmitter and the receiver. Its
difference from other models is that reflector is used to reflect light to the photoelectric
switch.Though the object between the photoelectric switch and reflector can reflect the light, it is
much less efficient than the reflector so as to cut down reflected light (Fig. R3)
Convergence reflection type (condensation type)
The working principle of convergence reflection type photo switch is similar to that of direct
reflection type one, while its projector and light receiver focus on object distance, only when the
object presents to the focus can the photo switch actuate.