A reflective sensor detects the presence of a subject at a detecting position. The sensor has a sensor portion and a filter. The sensor portion includes a light-emitting element that emits light at the detecting position and a light-receiving element that receives light reflected from the subject, and...http://www.google.com.au/patents/US6995358?utm_source=gb-gplus-sharePatent US6995358 - Reflective sensor, filter for reflective sensor, and method of detecting object using the same
