I'm using a touch LCD whose content I want to change if the user moves toward it. For this I'm looking for an SMT proximity sensor with a 40~50 cm detection range. Space above the PCB is only 3 mm, so Sharp GP2D12 and the like are out.
note - I'm not looking for shopping advice ("where can I buy part xyz?"), but rather design advice ("How can I solve this design problem?")