TWM587868U - Single-sided circuit board of light-emitting diode backlight module - Google Patents

Abstract

A light-emitting diode backlight module single-sided circuit board includes a substrate, a patterned copper foil, and a solder mask. The substrate has a working surface, and the patterned copper foil is formed on the working surface, and its thickness is less than 5 µm. The solder resist film is laminated on the patterned copper foil. The solder resist film has a plurality of solder pad windows and a part of the patterned copper foil is exposed. The solder mask windows are used as a plurality of light emitting diode chips. Form a channel for electrical connection with the patterned copper foil. As a result, the fineness of the prepared circuit can be significantly improved.

Description

Single-sided circuit board of light-emitting diode backlight module

The invention relates to a circuit board structure, in particular to a single-sided circuit board used in a light emitting diode backlight module.

With the development of micro-light emitting diode (mini LED) technology, the requirements for the fineness of its carrier board circuits have also increased. In the existing circuit carrier board structure, a thicker plated copper layer is plated on the substrate, and because the plated copper layer is thicker, during the process of circuitization, the problem of overcut will occur on the edge of the circuit, so the circuit The fineness is poor, and the wiring density cannot be effectively improved.

The main object of the present invention is to provide a circuit board which is helpful for achieving high circuit fineness and wiring density.

In order to achieve the above and other objectives, the present invention provides a single-sided circuit board of a light-emitting diode backlight module, which includes a substrate, a patterned copper foil, and a solder mask. The substrate has a working surface and the patterned copper foil is formed. On the working surface, and its thickness is less than 5 µm, the solder mask is laminated on the patterned copper foil. The solder mask has multiple pad openings and exposed part of the patterned copper foil. It is used as a channel for forming a plurality of light emitting diode chips to be electrically connected with the patterned copper foil.

By omitting the electroplated copper layer and directly patterning the copper foil with a thickness of less than 5 µm, the novel circuit significantly improves the fineness of the prepared circuit, can form fine circuits, and thus helps to achieve higher wiring density, which is consistent with Development trends in the field of microluminescent diode technology.

Please refer to FIG. 1, which shows an embodiment of a single-sided circuit board (hereinafter referred to as a single-sided circuit board) of the new type light-emitting diode backlight module. The single-sided circuit board has a substrate 10 and a pattern. A copper foil 20 and a solder resist film 30.

The substrate 10 may be made of a conventional circuit board, such as a FR-4 substrate. The substrate 10 has a working surface 11 and a non-working surface 12 on the opposite side. The working surface 11 is formed with a patterned copper foil 20. The patterned copper foil 20 is a copper foil subjected to a patterning process and has a circuit function. The copper foil 20 is laminated with a solder mask film 30. The solder mask film 30 has a plurality of pad opening windows 31 after windowing. The patterned copper foil 20 is exposed in the pad opening windows 31. The pad opening windows 31 can be used as A plurality of light emitting diode wafers 40 and the patterned copper foil 20 form an electrical connection channel. In order to improve the performance of the electrical connection, an electrical contact 41 between the patterned copper foil and the light emitting diode chip 40 is also formed. A non-copper metal plating layer 32, such as an electroplated nickel / gold layer. In order to improve the luminous efficacy, the reflectivity of the solder mask film 30 to the light in the visible wavelength range is greater than 80%, preferably greater than 85%, and more preferably greater than 90%. In addition, in order to meet the trend of thinning, the thickness of the solder mask 30 It is preferably less than 10 µm, which also helps to improve the precision of the circuit.

The process of the foregoing embodiment will be described below with reference to FIGS. 2 to 6.

As shown in FIG. 2, first, a substrate 10 with a copper foil 20A formed on one side is provided. At this time, the working surface 11 of the substrate 10 is covered with the copper foil 20A.

Next, as shown in FIG. 3, the copper foil 20A is subjected to a patterning process to obtain a patterned copper foil 20 having a circuit pattern. The patterning process is to attach a thin photolithographic layer on the copper foil 20A, expose and develop the photolithographic layer, etch copper not covered by the photolithographic layer, and finally remove the photolithographic layer.

As shown in FIG. 4, after the patterning process, the solder resist film 30 is laminated on the patterned copper foil 20. The solder resist film 30 is, for example, a semi-cured solder resist resin layer coated on a PET film in advance and passed through a laminator. Laminated with patterned copper foil 20, and then cured by curing the semi-cured solder resist resin.

As shown in FIG. 5, a laser engraving machine is used to perform window opening processing on the solder resist film 30 to form a plurality of pads to open the window 31 and expose a part of the patterned copper foil 20.

Next, as shown in FIG. 6, a non-copper metal plating layer, such as a nickel / gold plating layer, is plated on the pad opening window 31.

Finally, as shown in FIG. 1, the electrical contacts 41 of the light-emitting diode wafer 40 can be soldered to the metal plating layer 32, so that the light-emitting diode wafer 40 and the patterned copper foil 20 can be electrically connected to complete the single-sided circuit. Preparation of plates.

It can be known from the foregoing process that the formed single-sided circuit board does not form electroplated copper or drill holes on the substrate and the patterned copper foil, and only forms a circuit on the working surface of the substrate, and no circuit is formed on the non-working surface of the substrate.

To sum up, by omitting the electroplated copper layer and directly patterning the copper foil with a thickness of less than 5 µm, the precision of the prepared circuit is significantly improved, which can form a fine circuit, thereby helping to achieve higher wiring. The density is in line with the development trend in the field of microluminescent diode technology.

10‧‧‧ substrate
11‧‧‧Working surface
12‧‧‧ non-working face
20‧‧‧Graphic copper foil
20A‧‧‧copper foil
30‧‧‧Solderproof film
31‧‧‧ Pad window
32‧‧‧metal plating
40‧‧‧light-emitting diode chip
41‧‧‧electric contact

FIG. 1 is a schematic cross-sectional view of one embodiment of a single-sided circuit board of a novel light-emitting diode backlight module.

Figures 2 to 6 are schematic diagrams of the manufacturing process of one embodiment of the single-sided circuit board of the novel light-emitting diode backlight module.

Claims (7)

A single-sided circuit board of a light-emitting diode backlight module includes:
A substrate with a working surface;
A patterned copper foil is formed on the working surface, and the thickness of the patterned copper foil is less than 5 µm;
A solder mask is laminated on the patterned copper foil. The solder mask has a plurality of pads to open the window and expose a part of the patterned copper foil. The diode wafer and the patterned copper foil form an electrically connected channel. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein the reflectivity of the solder mask film to light in a wavelength range of visible light is greater than 80%. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein the maximum thickness of the solder mask is less than 10 µm. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein no holes are formed on the substrate and the patterned copper foil. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein copper plating is not formed on the substrate and the patterned copper foil. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein the single-sided circuit board of the light-emitting diode backlight module forms a circuit only on a working surface of the substrate. The single-sided circuit board of the light-emitting diode backlight module according to claim 1, wherein a non-copper metal plating layer is also formed on the patterned copper foil in the solder pad opening window.