Small low-profile optical proximity sensor
View Patent ↗In an embodiment, the invention provides a proximity sensor including a transmitter die, a receiver die, an ASIC die, a lead frame, wire bonds, a first transparent encapsulant, a second transparent encapsulant, and an opaque encapsulant. The transmitter die, the receiver die and the ASIC die are attached to portions of the lead frame. Wire bonds electrically connect the transmitter die, the receiver die, the ASIC die, and the lead frame. The first transparent encapsulant covers the receiver die, the ASIC die, the wire bonds, and a portion of the lead frame. The second transparent encapsulant covers the transmitter die, the wire bonds, and a portion of the lead frame. The opaque encapsulant covers portions of the first and second encapsulants and a portion of the lead frame.
1. A method of making a proximity sensor package, comprising:
providing a lead frame, the lead frame having a top and a bottom portion, wherein a first material is attached to a first portion of the bottom portion of the lead frame;
attaching a receiver die to a first portion of the top portion of the lead frame;
attaching a transmitter die to a second portion of the top portion of the lead frame;
attaching an ASIC die to a third portion of the top portion of the lead frame;
electrically coupling the receiver die, the transmitter die and the ASIC die to the lead frame;
concurrently forming a first transparent encapsulant over the receiver die, the ASIC die and a fourth portion of the top portion of the lead frame and a second transparent encapsulant over the transmitter die and a fifth portion of the top portion of the lead frame;
removing the first material attached to the first portion of the bottom portion of the lead frame;
attaching a second material to substantially all of the bottom portion of the lead frame;
forming an opaque encapsulant over a portion of the first transparent encapsulant, a portion of the second transparent encapsulant and a sixth portion of the top portion of the lead frame.
2. The method of claim 1 further comprising forming a first optical lens located over the receiver die currently while forming the first encapsulant.
3. The method of claim 1 further comprising forming a second optical lens located over the transmitter die currently while forming the second encapsulant.