Hamamatsu Corp.'s L8506 infrared LED emits a collimated light beam to produce the uniform light spot needed for use in optical encoders. The company says the device's high-speed response and reliability make it suitable for other applications that require a precision light source, such as in optical switches. The L8506 employs an aspheric lens that allows the LED to discharge a light beam with a directivity of ±5°. Typical specifications include a 4.3-mm spot size, response of 40 MHz and peak emission wavelength cutoff frequency of 870 nm. A nonconfined structure chip that does not easily deteriorate improves reliability. The system operates from -30 to 85 °C and measures 18.8 x 5.4 mm.