CN112291926A

CN112291926A - Single-sided circuit board of light-emitting diode backlight module

Info

Publication number: CN112291926A
Application number: CN201910676376.7A
Authority: CN
Inventors: 李远智; 李家铭
Original assignee: Uniflex Technology Inc
Current assignee: Uniflex Technology Inc
Priority date: 2019-07-25
Filing date: 2019-07-25
Publication date: 2021-01-29

Abstract

The application provides a single-sided circuit board of a light-emitting diode backlight module, which comprises a substrate, a graphical copper foil and a solder mask film, wherein the substrate is provided with a working surface, the graphical copper foil is formed on the working surface, the thickness of the graphical copper foil is less than 5 mu m, the solder mask film is laminated on the graphical copper foil, the solder mask film is provided with a plurality of welding pad windows to expose one part of the graphical copper foil, and the welding pad windows are used as channels for electrically connecting a plurality of light-emitting diode chips and the graphical copper foil. Therefore, the fineness of the prepared circuit can be obviously improved.

Description

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

Technical Field

The present disclosure relates to a circuit board structure, and more particularly, to a single-sided circuit board for a light emitting diode backlight module.

Background

With the development of micro light emitting diode (mini LED) technology, the requirement for the fineness of the carrier board circuit is also improved. In the existing circuit carrier plate structure, a thicker electroplated copper layer is electroplated on a substrate, and because the thickness of the electroplated copper layer is thicker, the problem of over etching (over etching) can be generated at the edge of a circuit in the process of routing, so that the circuit fineness is poorer, and the wiring density cannot be effectively improved.

Disclosure of Invention

In view of the above, the present disclosure is directed to a circuit board that facilitates high circuit fineness and high wiring density.

In order to achieve the above and other objects, the present application provides a single-sided circuit board for a led backlight module, which includes a substrate, a patterned copper foil and a solder mask film, wherein the substrate has a working surface, the patterned copper foil is formed on the working surface, and the thickness of the patterned copper foil is less than 5 μm, the solder mask film is laminated on the patterned copper foil, the solder mask film has a plurality of solder pad windows exposing a portion of the patterned copper foil, and the solder mask windows are used as channels for electrically connecting a plurality of led chips with the patterned copper foil.

According to the method, the copper plating layer is omitted, the copper foil with the thickness smaller than 5 mu m is directly subjected to graphical processing, the fineness of the prepared circuit is remarkably improved, a fine circuit can be formed, the realization of high wiring density is facilitated, and the development trend in the technical field of micro light-emitting diodes is met.

Further details regarding other functions and embodiments of the present application are described below with reference to the accompanying drawings.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic cross-sectional view of one embodiment of a single-sided circuit board of a light-emitting diode backlight module according to the present application;

fig. 2 to 6 are schematic views illustrating a manufacturing process of an led backlight module single-sided circuit board according to an embodiment of the present invention.

Description of the symbols

10 substrate 11 working surface

12 non-working side 20 patterned copper foil

20A copper foil 30 solder mask

31 pad windowed 32 metallization

40 led chip 41 electrical contact

Detailed Description

Referring to fig. 1, an embodiment of a single-sided circuit board (hereinafter referred to as a single-sided circuit board) of a led backlight module of the present application is shown, wherein the single-sided circuit board has a substrate 10, a patterned copper foil 20 and a solder mask 30.

The substrate 10 may be a conventional circuit board, such as an FR-4 substrate. The substrate 10 has a working surface 11 and a non-working surface 12 on the opposite surface, the working surface 11 is formed with a patterned copper foil 20, the patterned copper foil 20 is a copper foil subjected to patterning treatment and has a circuit function, the patterned copper foil 20 is laminated with a solder mask film 30, the solder mask film 30 is subjected to windowing treatment and has a plurality of pad windows 31, the patterned copper foil 20 is exposed in the pad windows 31, the pad windows 31 can be used as channels for electrically connecting a plurality of led chips 40 and the patterned copper foil 20, and in order to improve the efficiency of electrical connection, a non-copper metal plating layer 32, such as an electroplated nickel/gold layer, is further formed between the patterned copper foil and electrical contacts 41 of the led chips 40. In order to improve the light emitting efficiency, the reflectivity of the solder mask 30 to the light in the visible wavelength range is greater than 80%, preferably greater than 85%, and more preferably greater than 90%, and in order to meet the trend of thinning, the thickness of the solder mask 30 is preferably less than 10 μm, which also helps to improve the circuit precision.

The process of the foregoing embodiment is described below with reference to fig. 2 to 6.

As shown in fig. 2, first, a substrate 10 having a copper foil 20A formed on one surface thereof is provided, and 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 patterning treatment to obtain a patterned copper foil 20 having a circuit pattern. The patterning process is performed by attaching a thin photoresist layer to the copper foil 20A, exposing and developing the photoresist layer, etching the copper not covered by the photoresist layer, and finally removing the photoresist layer.

As shown in fig. 4, after the patterning process, the solder resist film 30 is laminated on the patterned copper foil 20, and the solder resist film 30 is obtained by laminating a semi-cured solder resist resin layer, which is previously coated on a PET film, on the patterned copper foil 20 by a laminating machine, and then curing the semi-cured solder resist resin.

As shown in fig. 5, the solder mask film 30 is windowed by a laser engraving machine to form a plurality of pad windows 31 exposing a portion 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 in the pad window 31.

Finally, as shown in fig. 1, the electrical contacts 41 of the led chip 40 are soldered to the metal plating layer 32, so that the led chip 40 and the patterned copper foil 20 are electrically connected to complete the preparation of the single-sided circuit board.

In the above process, it is known that the single-sided wiring board is formed without forming plated copper or drilling holes on the substrate and the patterned copper foil, and that the circuit is formed only on the active surface of the substrate, and the circuit is not formed on the non-active surface of the substrate.

In summary, according to the method, the copper plating layer is omitted, the copper foil with the thickness smaller than 5 microns is directly subjected to graphical processing, the fineness of the manufactured circuit is remarkably improved, a fine circuit can be formed, the realization of high wiring density is facilitated, and the development trend in the technical field of micro light-emitting diodes is met.

The above-described embodiments and/or implementations are only illustrative of the preferred embodiments and/or implementations for implementing the technology of the present application, and are not intended to limit the implementations of the technology of the present application in any way, and those skilled in the art can make many changes or modifications to the equivalent embodiments without departing from the scope of the technology disclosed in the present application, but should still be considered as the technology or implementations substantially the same as the present application.

Claims

1. A single-sided circuit board of a light emitting diode backlight module is characterized by comprising:

a substrate having a working surface;

a patterned copper foil formed on the working surface, wherein the thickness of the patterned copper foil is less than 5 μm;

and the solder mask film is laminated on the graphical copper foil and is provided with a plurality of welding pad windows which expose one part of the graphical copper foil and are used as channels for forming electrical connection between the plurality of light-emitting diode chips and the graphical copper foil.

2. The LED backlight module single-sided wiring board of claim 1, wherein the solder mask film has a reflectance of greater than 80% for light in the visible wavelength range.

3. The single-sided wiring board for led backlight module of claim 1, wherein the maximum thickness of the solder mask film is less than 10 μm.

4. The LED backlight module single-sided wiring board of claim 1, wherein the substrate and the patterned copper foil do not have holes drilled therein.

5. The LED backlight module single-sided wiring board of claim 1, wherein the substrate and the patterned copper foil are free of electroplated copper.

6. The LED backlight single-sided circuit board of claim 1, wherein the LED backlight single-sided circuit board forms circuitry only on the active side of the substrate.

7. The LED backlight module single-sided circuit board of claim 1, wherein the patterned copper foil in the pad windows further has a non-copper metal plating layer_。