The invention is directed to a printed circuit board comprising an insulating bulk layer having a proximal surface and a distal surface that is opposite to the proximal surface with one or more electrical connection elements accessible from the proximal surface of the insulating bulk layer. The electrical connection elements are configured to connect electrical components to be arranged on the proximal surface of the insulating bulk layer, wherein the distal surface is at least partially covered by a distal conductive layer that is electrically isolated from the electrical connection elements.

A method for manufacturing a printed wiring board includes forming a resin insulating layer on a first conductor layer, forming a protective film on a surface of the insulating layer, forming opening through the protective film and insulating layer, removing the film, cleaning the surface of the insulating layer, forming a second conductor layer on the surface of the insulating layer; and forming a via conductor connecting the first and second conductor layers in the opening. The insulating layer includes resin and inorganic particles having spherical shapes, the cleaning includes selectively removing the resin such that the particles include first particles partially embedded and second particles completely embedded in the resin. The forming the second conductor layer includes forming a seed layer by sputtering, forming a plating resist using DI exposure, forming an electrolytic plating layer, removing the resist, and removing the seed layer exposed from the electrolytic plating layer.

A process method for laser removal of substrate solder mask by: providing a substrate with solder pads; covering the substrate and the solder pads with a solder mask, where the part of the solder mask facing the substrate is the shielding part and the part of the solder mask facing the solder pads is the clearing part; using a camera module to read the QR-code for plate production part number on the substrate; automatically importing the CAD/CAM data to the laser device, where the CAD/CAM data corresponds to the plate production part number; sequentially stripping the cleaning part through the laser beam according to the CAD/CAM data to make the solder mask form a hollow portion; taking a picture of the substrate and taking out the processed substrate picture; completing the substrate processing job if the processed substrate picture and the CAD/CAM data are the same.

Methods, systems, and devices for manufacturing a wearable device are described. Techniques described herein may enable a method for forming one or more dome-shaped protrusions over apertures of a wearable device usable to collect physiological data from a user. For example, a manufacturing process may include adhering a layer of a material with a relatively lower surface energy than metal onto an outer surface of the inner housing of the wearable device prior to dispensing an optically transparent material into the apertures. The optically transparent material may accordingly form the dome-shaped protrusions while in contact with the layer, which may enable the optically transparent material to form relatively higher dome-shaped protrusions as compared to a dome-shaped protrusion formed on a metal material. The layer may be removed following dispensing of the optically transparent material.

A wiring board include: a base material; a wiring disposed on the base material; and a cover lay laminated on the base material and that covers the wiring. The cover lay includes an open portion exposing a part of the wiring, the cover lay includes a protection layer and an adhesive layer that adheres the protection layer to the base material, the cover lay has burrs that do not contact the base material at an edge portion of the cover lay along the open portion, an end face of the adhesive layer that faces the open portion contacts the wiring, and an end portion of the adhesive layer that constitutes the burrs is outside the end face of the adhesive layer.