Wrap-around overmold for electronic assembly
View Patent ↗An improved overmolded electronic assembly includes a backplate provided with a recessed edge, a circuit substrate on the backplate, at least one electronic component mounted on the circuit substrate, conductive traces on the circuit substrate which together with the electronic component(s) defines a circuit device, an electrical connector, and an overmold body that has peripheral edges that wrap around sides of the backplate and onto the edge recesses. The resulting over wrap feature eliminates delamination problems that would otherwise occur during thermal cycling of the electronic assembly, improves corrosion resistance at connector-to-backplate interfaces, and enhances securement of the printed circuit board assembly and electrical connector to the assembly.
1. An overmolded electronic assembly comprising:
a generally planar backplate having opposite top and bottom surfaces, side surfaces, and edge recesses between the side and bottom surfaces;
a circuit substrate on the top surface of the backplate;
at least one electronic component mounted on the circuit substrate;
electrically conductive traces defined on the circuit substrate, the electrically conductive traces and the at least one electronic component together defining a circuit device on the circuit substrate;
an electrical connector joined to the circuit substrate, the electrical connector including a thermoplastic wall member having an inner side and an outer side, a plurality of electrically conductive elements extending through the thermoplastic wall member, a section of each electrically conductive element projecting away from the outer side of the thermoplastic wall member to define external connector pins, and a section of each electrically conductive element extending from the inner side of the thermoplastic wall member toward the circuit substrate and electrically connected to the circuit device defined on the circuit substrate; and
an overmold body disposed directly over the circuit substrate and around peripheral edges of the backplate and the electrical connector, the overmold body together with the backplate and thermoplastic wall member of the electrical connector sealingly encasing the circuit substrate and the circuit device defined on the substrate, the overmold body having a peripheral edge that wraps around the sides of the backplate and onto the edge recesses.
2. The assembly of claim 1 , wherein the circuit substrate is adhesively bonded to the backplate.
3. The assembly of claim 1 , wherein the circuit substrate is mechanically fastened to the backplate.
4. The assembly of claim 1 , wherein an integral shroud projects from the thermoplastic wall member and surrounds the external connector pins.
5. The assembly of claim 1 , wherein the backplate is comprised of a metal or metal alloy.
6. The assembly of claim 1 , wherein the backplate is comprised of an aluminum or an aluminum alloy.
7. The assembly of claim 1 , wherein the backplate is comprised of a thermoplastic.