Abstract: A light-emitting diode structure includes a light-emitting part and a reflective part. The light-emitting part has a light-emitting surface. The reflective part is on the light-emitting part opposite to the light-emitting surface. The reflective part is a gradient distributed Bragg reflection structure and includes a plurality of first dielectric layers and a plurality of second dielectric layers. The second dielectric layers have a refractive index different from that of the first dielectric layer, and are alternately stacked with the first dielectric layers. Each of the first dielectric layers has a different optical thickness, and each of the second dielectric layers has a different optical thickness. The optical thicknesses of the first dielectric layers and the second dielectric layers vary in a gradient way away from the light-emitting part.

Abstract: A lens module includes a holder base, which is affixed to a circuit board and has bottom receiving holes for receiving LEDs or sensors on the circuit board and a top flange with a foolproof notch, a lens device press-fitted into the top flange and secured to the foolproof notch to ensure accurate positioning and having flat protrusions engaged into respective through holes in the holder base in alignment with the LEDs or sensors, and a top cover capped on the holder base to hold down the lens device and having through holes that receive convex portions of the lens device respectively.

Abstract: A lens module includes a holder base, which is affixed to a circuit board and has bottom receiving holes for receiving LEDs or sensors on the circuit board and a top flange with a foolproof notch, a lens device press-fitted into the top flange and secured to the foolproof notch to ensure accurate positioning and having flat protrusions engaged into respective through holes in the holder base in alignment with the LEDs or sensors, and a top cover capped on the holder base to hold down the lens device and having through holes that receive convex portions of the lens device respectively.

Abstract: A valuable paper validator for use in a vending (coin change) machine is disclosed to include a delivery unit for delivering a valuable paper through a delivery path, a LED package having multiple LED chips spaced above the delivery path and controllable to emit different wavelengths of intense pulsed light, a collimator lens for collimating light passing from the LED package through the valuable paper, a photodiode spaced below the delivery path for collecting light passed through the valuable paper for verifying the authenticity of the valuable paper, and a condensing lens for focusing different wavelengths of light passed through the valuable paper onto the photodiode.

Abstract: A detachable bill acceptor mounting arrangement includes a face panel of a vending machine, the face panel having two protruding locating plates at two sides and an angled guide groove at each protruding locating plate, and a bill acceptor formed of a lower unit and an upper unit, the lower unit having two recessed locating portions detachably coupled to the protruding locating plates of the face panel and two pair of stub guide rods insertable into the angled guide grooves to secure the lower unit to the face panel, the upper unit having two flat pivot rods detachably coupled to a respective pivot hole on the lower unit and two hooks releasably hooked in a respective retaining slot on the lower unit to lock the upper unit to the lower unit.