Abstract: A circuit board structure includes a carrier, a thin film redistribution layer disposed on the carrier, solder balls electrically connected to the thin film redistribution layer and the carrier, and a surface treatment layer. The thin film redistribution layer includes a plurality of pads, a first dielectric layer, a first metal layer, a second dielectric layer, a second metal layer, and a third dielectric layer. A plurality of first openings of the first dielectric layer expose part of the pads, and a first surface of the first dielectric layer is higher upper surfaces of the pads. The solder balls are disposed in a plurality of third openings of the third dielectric layer and are electrically connected to the second metal layer and the carrier. The surface treatment layer is disposed on the upper surfaces, and a top surface of the surface treatment layer is higher than the first surface.

Abstract: A thermally conductive board includes a metal substrate, a metal layer, a thermal conductive insulating polymer layer, and a ceramic material layer. The thermal conductive insulating polymer layer is located between the metal layer and the metal substrate. The ceramic material layer includes an upper ceramic layer or a lower ceramic layer, or includes both the upper ceramic layer and the lower ceramic layer. The upper ceramic layer is disposed between the metal layer and the thermal conductive insulating polymer layer, and the lower ceramic layer is disposed between the thermal conductive insulating polymer layer and the metal substrate.

Abstract: A thermally conductive board includes a metal substrate, a metal layer, a thermal conductive insulating polymer layer, and a ceramic material layer. The thermal conductive insulating polymer layer is located between the metal layer and the metal substrate. The ceramic material layer includes an upper ceramic layer or a lower ceramic layer, or includes both the upper ceramic layer and the lower ceramic layer. The upper ceramic layer is disposed between the metal layer and the thermal conductive insulating polymer layer, and the lower ceramic layer is disposed between the thermal conductive insulating polymer layer and the metal substrate.

Abstract: A lubrication system for a four stroke engine including an oil pan for storing lubrication oil; a crankcase, wherein a crankshaft is disposed, which crankshaft has a balance weight and is coupled with a piston of a cylinder; a gear assembly room; a rocker-arm chamber; and a gas-oil separator for separating gas and oil from a mix of gas and oil; wherein the oil pan communicates with the crankcase by an oil suction passage, in which a first check valve is disposed; the crankcase communicates with the gear assembly room by a first oil delivery passage; the gear assembly room communicates with the rocker-arm chamber by a second oil delivery passage, and the gear assembly room communicates with the oil pan by a third oil delivery passage; the rocker-arm chamber communicates with the crankcase by a first oil return passage having a second check valve therein.

Abstract: A lubrication system for a four stroke engine including an oil pan for storing lubrication oil; a crankcase, wherein a crankshaft is disposed, which crankshaft has a balance weight and is coupled with a piston of a cylinder; a gear assembly room; a rocker-arm chamber; and a gas-oil separator for separating gas and oil from a mix of gas and oil; wherein the oil pan communicates with the crankcase by an oil suction passage, in which a first check valve is disposed; the crankcase communicates with the gear assembly room by a first oil delivery passage; the gear assembly room communicates with the rocker-arm chamber by a second oil delivery passage, and the gear assembly room communicates with the oil pan by a third oil delivery passage; the rocker-arm chamber communicates with the crankcase by a first oil return passage having a second check valve therein.