Method for detecting full-sealing effect of FPC (Flexible Printed Circuit) of display module

Abstract

The invention discloses a full-sealing effect detection method for a display module FPC, and the method comprises the following steps: 1, providing a resistance detection tool, first conductive foam, second conductive foam and a to-be-detected module FPC, forming a golden finger region and a component region on the to-be-detected module FPC, the golden finger region comprises a plurality of golden fingers electrically connected with a display module, and the component region comprises a plurality of first conductive foam and a plurality of second conductive foam; the component area is provided with full sealing glue, the first conductive foam is electrically connected with the negative electrode of the resistance value detection jig, and the second conductive foam is electrically connected with the positive electrode of the resistance value detection jig. According to the invention, the problem of incomplete full glue sealing of the component can be effectively detected; the design and test method is simple and can be widely used; the cost is low, and limitation and instability of naked eye inspection can be effectively avoided.

Description

Technical Field

[0001] This invention relates to the field of display module technology, and in particular to a method for testing the full sealing effect of display module FPC. Background Technology

[0002] The mobile phone industry now demands increasingly higher reliability, necessitating full encapsulation of components on the display module FPC. This provides excellent protection for components during salt spray or high-temperature, high-humidity testing, preventing damage and improving product reliability. When using full encapsulation, fluorescent adhesives are typically chosen. After application, the entire component is visually inspected under fluorescent light to ensure complete coverage. However, this conventional method relies on visual inspection. Due to the adhesive's fluidity and unevenness, some areas may not be fully covered, making it difficult for the human eye to detect. This limitation easily leads to missed or incorrect assessments, resulting in some components not being fully covered, causing product failure or malfunctions after testing, and wasting company resources. Therefore, existing technologies have shortcomings and need to be improved. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for testing the full sealing effect of display module FPC.

[0004] The technical solution of the present invention is as follows: The present invention provides a method for testing the full sealing effect of a display module FPC, comprising the following steps: Step 1: Provide a resistance testing fixture, a first conductive foam, a second conductive foam, and a test module FPC. The test module FPC has a gold finger area and a component area. The gold finger area includes a plurality of gold fingers for electrical connection with the display module. The component area is fully encapsulated. The first conductive foam is electrically connected to the negative electrode of the resistance testing fixture, and the second conductive foam is electrically connected to the positive electrode of the resistance testing fixture. Step 2: Place the FPC module under test, such that the gold finger area of ​​the FPC module under test is placed on the second conductive foam, the second conductive foam covers all the gold fingers of the gold finger area, and the second conductive foam is electrically connected to all the gold fingers of the gold finger area. Step 3: Press the first conductive foam onto the component area of ​​the FPC module under test and start resistance detection. During the pressing process, the compression size of the first conductive foam shall not exceed the thickness of the first conductive foam. After pressing, maintain the position for a predetermined time and then release the pressing. During pressing, the first conductive foam shall cover the component area of ​​the FPC module under test. During resistance detection, the detection fixture shall obtain the resistance between its positive and negative terminals. If the resistance is greater than or equal to the predetermined value during the pressing process, it indicates that the full sealing effect is unqualified. If the resistance is less than the predetermined value during the pressing process, it indicates that the full sealing effect is qualified.

[0005] Furthermore, in step 3, the first conductive foam is held in place for 5 to 10 seconds after being pressed into position.

[0006] Furthermore, in step 3, when the first conductive foam exerts a pressing force of 0.7MPa to 0.9MPa on the FPC module under test, it is determined that the pressing is in place.

[0007] Furthermore, the predetermined resistance value is 1MΩ.

[0008] Furthermore, the thickness of the first conductive foam is 2mm-5mm; the thickness of the second conductive foam is 0.5mm-3mm.

[0009] The advantages of this invention using the above solution are: it can effectively detect problems of incomplete encapsulation of components; the design and testing methods are simple and can be used in large quantities; the cost is low and it can effectively avoid the limitations and instability of visual inspection. Detailed Implementation

[0010] The present invention will be described in detail below with reference to specific embodiments.

[0011] In this embodiment, the present invention provides a method for detecting the full sealing effect of a display module FPC, comprising the following steps: Step 1: Provide a resistance testing fixture, a first conductive foam, a second conductive foam, and a module under test (FPC). The FPC has a gold finger area and a component area. The gold finger area includes several gold fingers for electrical connection with the display module. The component area is fully encapsulated. The first conductive foam is electrically connected to the negative electrode of the resistance testing fixture, and the second conductive foam is electrically connected to the positive electrode of the resistance testing fixture. Step 2: Place the FPC module under test, such that the gold finger area of ​​the FPC module under test is placed on the second conductive foam, the second conductive foam covers all the gold fingers of the gold finger area, and the second conductive foam is electrically connected to all the gold fingers of the gold finger area. Step 3: Press the first conductive foam onto the component area of ​​the FPC module and initiate resistance detection. During the pressing process, the compression size of the first conductive foam shall not exceed the thickness of the first conductive foam to avoid damage to the components. After pressing, hold for 5 to 10 seconds before releasing the pressing. During pressing, the first conductive foam shall cover the component area of ​​the FPC module. During resistance detection, the detection fixture shall obtain the resistance between its positive and negative terminals. If the resistance is greater than or equal to the predetermined value during the pressing process, it indicates that the full sealing effect is unqualified. If the resistance is less than the predetermined value during the pressing process, it indicates that the full sealing effect is qualified. The predetermined resistance value can be 1MΩ.

[0012] In this solution, since the exposed copper areas (such as component pads) in the FPC module under test are electrically connected to the gold fingers in the gold finger area, if the sealing effect of the encapsulant is good, the encapsulant will prevent the first conductive foam from connecting to the pads in the component area. Therefore, during resistance testing, the first and second conductive foams will not be connected. If the resistance between the first and second conductive foams is less than the predetermined value during resistance testing, it indicates that the first and second conductive foams are electrically connected, meaning the encapsulant has not achieved the corresponding sealing effect, preventing the first conductive foam from directly contacting the component pads during pressing. By adopting this method, the sealing effect of the encapsulant can be quickly and accurately tested through convenient resistance testing, and it is a non-destructive test.

[0013] Furthermore, in step 3, when the first conductive foam exerts a pressing force of 0.7MPa to 0.9MPa on the FPC module under test, it is determined that the pressing is in place.

[0014] Specifically, the first conductive foam has a thickness of 2mm-5mm, a length of ≤20mm, and a width of ≤10mm, ensuring coverage of the component area while avoiding excessive length or width. The second conductive foam has a thickness of 0.5mm-3mm, a length of ≥50mm, and a width of ≥1mm, ensuring good electrical connection with the gold fingers in the gold finger area.

[0015] In summary, this solution can effectively detect incomplete encapsulation of components; the design and testing methods are simple and can be used extensively; the cost is low and it can effectively avoid the limitations and instability of visual inspection.

[0016] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for detecting full encapsulation effect of a display module FPC, characterized in that, The method comprises the following steps: step 1: providing a resistance detection jig, a first conductive foam, a second conductive foam and a to-be-tested module FPC, the to-be-tested module FPC is formed with a gold finger area and a component area, the gold finger area comprises a plurality of gold fingers for electrically connecting with a display module, the component area is provided with a full encapsulation glue, the first conductive foam is electrically connected with a negative electrode of the resistance detection jig, and the second conductive foam is electrically connected with a positive electrode of the resistance detection jig; step 2: placing the to-be-tested module FPC, so that the gold finger area of the to-be-tested module FPC is placed on the second conductive foam, the second conductive foam corresponds to all gold fingers of the gold finger area, and the second conductive foam is electrically connected with all gold fingers of the gold finger area; step 3: making the first conductive foam press-fit to the component area of the to-be-tested module FPC and starting resistance detection, the compression size of the first conductive foam in the press-fit process is not more than the thickness of the first conductive foam, the press-fit is kept for a predetermined time after the press-fit is in place, and then the press-fit is released, and the first conductive foam corresponds to the component area of the to-be-tested module FPC during the press-fit, the resistance detection jig obtains the resistance between the positive electrode and the negative electrode during the resistance detection, when the resistance is greater than or equal to a predetermined value during the press-fit process, it is indicated that the full encapsulation glue is unqualified, and when the resistance is less than the predetermined value during the press-fit process, it is indicated that the full encapsulation glue is qualified.

2. The display module FPC total encapsulation effect detection method according to claim 1, characterized in that, The keeping time of the first conductive foam in step 3 is 5 seconds to 10 seconds after the press-fit is in place. 3.The display module FPC full encapsulation effect detection method according to claim 2, characterized in that, In step 3, when the press-fit force of the first conductive foam to the to-be-tested module FPC reaches 0.7 MPa to 0.9 MPa, it is determined that the press-fit is in place.

4. The display module FPC full encapsulation effect detection method according to any one of claims 1 to 3, characterized in that, The predetermined value of the resistance is 1 MΩ.

5. The display module FPC full encapsulation effect detection method according to any one of claims 1 to 3, characterized in that, The thickness of the first conductive foam is 2 mm to 5 mm, and the thickness of the second conductive foam is 0.5 mm to 3 mm.