Patent ID: 12245373

DETAILED DESCRIPTION OF THE EMBODIMENTS

More detailed descriptions of specific embodiments of the disclosure are provided below with reference to the schematic diagrams. The advantages and features of the disclosure are described more clearly according to the following description and claims. It should be noted that all of the drawings use very simplified forms and imprecise proportions, only being used for assisting in conveniently and clearly explaining the objective of the embodiments of the disclosure.

FIG.1is a schematic cross-sectional view of an embodiment of a printed circuit board according to the disclosure. As shown in the figure, the printed circuit board100includes a substrate120, an electrically conductive pattern layer140, and a thermally conductive ink layer160.

The substrate120includes a first surface122. The electrically conductive pattern layer140is located on the first surface122and includes a contact portion142and a wire portion144. At least one electronic element, such as a wafer, a resistor, an inductor, and a capacitor, is disposed on the contact portion142, and is connected to another element by the wire portion144.

In an embodiment, the substrate120is either a rigid substrate or a flexible substrate.

In an embodiment, the electrically conductive pattern layer140is either a copper metal layer or an aluminum metal layer.

In an embodiment, the contact portion142of the electrically conductive pattern layer140includes a contact pad, a via hole, or both. The contact pad is used as an example in the figure. The contact pad is used for electrically connecting to a surface mount device, and the via hole is used for electrically connecting to a plug-in unit.

The thermally conductive ink layer160covers the wire portion144of the electrically conductive pattern layer140and exposes the contact portion142.

In an embodiment, the thermally conductive ink layer160covers a part of the first surface122, and has an opening left in a region corresponding to the contact portion142to facilitate installation of the electronic element. In terms of a manufacturing process, the thermally conductive ink layer160is formed in a printing or spraying manner.

The thermally conductive ink layer160includes a thermally conductive powder162and a colloidal adhesive164. The thermally conductive powder162is uniformly distributed in the colloidal adhesive164. By adjusting a proportion of the thermally conductive powder162in the thermally conductive ink layer160or using an electrically non-conductive thermally conductive powder162, the thermally conductive ink layer160produces an insulation effect to facilitate replacement of a conventional solder mask. In this way, use of the solder mask is omitted to reduce manufacturing costs.

In an embodiment, the thermally conductive powder162is a non-metallic thermally conductive powder to provide an insulation effect. In an embodiment, the thermally conductive powder162is selected from a group consisting of a carbon powder, a graphene powder, a hexagonal boron carbide powder, a carbon nanopowder, a carbon fiber powder, and a diamond powder.

In an embodiment, the colloidal adhesive164is either a light-cured material or a heat-cured material.

In an embodiment, a weight percentage of the thermally conductive powder162is less than 10%, and a weight percentage of the colloidal adhesive164is higher than 80%. In an embodiment, a small amount of dispersant is added into thermally conductive ink to improve the uniformity of the thermally conductive powder162.

In an embodiment, the thermally conductive ink layer160is coated on both an upper surface and a lower surface of the substrate120to improve heat dissipation.

In an embodiment, the thermally conductive ink layer160is located on an uppermost layer (instead of the solder mask) of the printed circuit board100, or is located on an inner interlayer of a multi-layer printed circuit board for insulation, to improve heat dissipation of the printed circuit board.

FIG.2is a schematic cross-sectional view of an embodiment of an electronic device10according to the disclosure. The electronic device10includes the printed circuit board100shown inFIG.1, an electronic element200, and a thermally conductive material layer300. The electronic device10is either a motherboard or another electronic module including the printed circuit board100.

The electronic element200is disposed on the thermally conductive ink layer160and is connected to the contact portion142of the electrically conductive pattern layer140. The electronic element200is either a surface mount device or a plug-in unit. The surface mount device is used as an example in the figure. The surface mount device is electrically connected to the contact pad. Secondly, the electronic element is either a packaged element or a bare die.

The thermally conductive material layer300covers the electronic element200and extends to come into contact with the thermally conductive ink layer160. The thermally conductive material layer300forms a thermally conductive path to transfer heat generated by operation of the electronic element200to the thermally conductive ink layer160.

The heat generated during operation of the electronic element200is transferred to the printed circuit board100through the contact portion142of the electrically conductive pattern layer140for being discharged outside, or is transferred to the printed circuit board100through the thermally conductive material layer300for being discharged outside. In this way, the temperature of the electronic element200is prevented from being excessively high. In an embodiment, the thermally conductive material layer300completely covers the electronic element200.

In an embodiment, the thermally conductive material layer300and the thermally conductive ink layer160are made of different materials. In an embodiment, for the thermally conductive material layer300, a thermally conductive powder162having the same proportion and the same type as those in the thermally conductive ink layer160is adopted, but a colloidal adhesive364with relatively good fluidity is selected to facilitate coating the thermally conductive material layer300on the electronic element200in a spraying manner.

In addition, it is considered that the thermally conductive material layer300needs to effectively cover the electronic element200, the colloidal adhesive364with higher viscosity is selected to ensure that the thermally conductive material layer300has a sufficient thickness. In another embodiment, to reduce manufacturing costs, the material composition of the thermally conductive material layer300is the same as the material composition of the thermally conductive ink layer160.

The printed circuit board100provided in the disclosure includes the thermally conductive ink layer160to replace a conventional solder mask. The thermally conductive ink layer160includes the thermally conductive powder162inside, to provide an effective thermal conduction effect while maintaining an insulation property, to resolve a problem that product performance of printed circuit board products degrades because of heat accumulation of electronic elements.

The above are merely preferred embodiments of the disclosure, and do not constitute any limitation on the disclosure. Any form of equivalent replacements or modifications to the technical means and technical content disclosed in the disclosure made by a person skilled in the art without departing from the scope of the technical means of the disclosure still fall within the content of the technical means of the disclosure and the protection scope of the disclosure.