I am using an IR sensor (vishay tsop32 series) but I want to ensure that it only sender directly ahead so I made blinders out of pla and covered them in aluminium foil. However it seems that despite this the IR signal is able to be detected through the foil. Even when I surround the sensor with aluminium foil it is sensing an IR signal. The aluminium foil has decreased the sensing distance but not as much as is necessary. I'm wondering why this is not working as well as expected and what materials might work better as blinders for the sensor.