Ultra-miniature surface mount type overcurrent and overheat protection device and manufacturing method thereof

Abstract

The invention discloses a subminiature surface-mounted type over-current over-heat protection device and a manufacture method thereof. The device is a rectangular body and comprises a PTC (Phenylthiocarbamide) layer, nickel-plated copper foil / pure nickel foil layers, a copper layer and a nickel layer, and a stannum layer and a gold layer / silver layer, wherein the nickel-plated copper foil / pure nickel foil layers are attached to the upper surface and the lower surface of the PTC layer; and the copper layer and the nickel layer, and the stannum layer and the gold layer / silver layer are orderly prepared on the nickel-plated copper foil / pure nickel foil layers by means of film growth or electroplating. The manufacture method of the over-current over-heat protection device comprises the following steps of: taking a PTC sheet comprising one PTC layer and two electrode nickel-plated copper foil / pure nickel foil layers attached to the upper surface and the lower surface of the PTC layer; additionally arranging conductive metal layers and soldering fluxes on the surfaces of the nickel-plated copper foil / pure nickel foil layers by means of the film growth or electroplating; then cutting the sheet to pretty small single units; and finally attaching a solder resistant insulating layer on the surface of the device by means of screen printing. By adopting the method disclosed by the invention, the more subminiature surface-mounted type over-current over-heat protection device can be conveniently obtained to adapt to increasingly miniaturized electronic products.

Description

technical field [0001] The invention relates to a surface mounting type overcurrent and overheating protection device, in particular to an ultra-small surface mounting type overcurrent and overheating protection device and a manufacturing method thereof. Background technique [0002] Conventional surface-mounted overcurrent and overheating protection devices are manufactured using printed circuit board technology. The specific production method of this craft is: [0003] Step 1. Take a PTC sheet 1', and provide a through hole 2' for each overcurrent and overheat protection device formed by the PTC sheet by mechanical or laser drilling (see figure 1 ); [0004] Step 2, after cleaning the dirt in the hole, electroplate the metal copper layer 3' and the solder layer 4' on the surface of the electrode and the inner wall of the through hole 2' in sequence (see figure 2 ); [0005] Step 3. Cover the two surfaces of the plate 1' with a photosensitive dry film, and then expose ...

AI Technical Summary

Problems solved by technology

However, the conventional surface mount overheating and overcurrent protection device structure requires etching electrodes to separate the electrodes on the same plane, which greatly reduces the effective area of ​​the mounting device, and its carrying current is greatly reduced, which cannot meet the needs of electronic products.

[0011] In addition, conventional surface-mounted overcurrent and overheating protection devices are manufactured using a printed circuit manufacturing process, which needs to consider the alignment accuracy of the front and back electrodes and etching grooves, and the processing of surface mount devices with a size of 0402 or smaller is very difficult. Big

[0012] Therefore, for surface mount devices with a size of 0402 or smaller, according to the above-mentioned current conventional methods, not only the production cost is high, but also the production is difficult, which cannot meet the needs of increasingly miniaturized electronic products.

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