Patent Application
20080144923
1. Field of the Invention
The present invention generally relates to a test apparatus and a test method for testing contact fingers of printed circuit boards.
2. Description of Related Art
Printed circuit boards (PCBs) are widely used in electronic devices, such as computers, mobile phones. The PCBs are electrically connected to connectors of other electronic components in the electronic devices. The PCB includes contact fingers that are rows of tabs along one or more edges of the PCB. These tabs fit into the connectors of the other electronic components. Electronic signals are transmitted between the PCBs and the other electronic components through the contact fingers. For instance, referring to
In order to be durable and resistant to tarnishing and oxidation, the contact fingers that are mainly constructed with copper tracks need to be overlaid with gold. Herein, gold is used because of its excellent conductivity and resistance to oxidation. However, there are many faults in the PCBs usually generated in manufacture or in use. Referring to
However, these faults are slight, and almost invisible to the naked eye. In practice, a manual method is used for testing the contact finger to find the faults using magnifiers. However, the test efficiency and accuracy of the manual method is low.
Therefore, a contact finger test apparatus and a contact finger test method are needed in the industry to address the aforementioned deficiencies and inadequacies.
A contact finger test apparatus is used for testing contact fingers of a printed circuit board. The contact finger test apparatus comprises a sampler, a processor and an image-analyzer module. The sampler is for capturing an image of the contact fingers, and converting the image to the digital image. The processor is for optimizing the digital image. The image-analyzer module is for analyzing the digital image to obtain a conclusion whether there are faults in the contact fingers. A contact finger test method is also disclosed.
Other systems, methods, features, and advantages of the present contact finger test apparatus and the present contact finger test method will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present device, and be protected by the accompanying claims.
Many aspects of the present contact finger test apparatus and the present contact finger test method can be better understood with reference to following drawings. Components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present device. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.
Reference will now be made to the drawings to describe preferred embodiments of the present contact finger test apparatus and the present contact finger test method.
Referring to
Referring to
When the value of the difference-frequency signal is greater than the predetermined threshold value, the first comparator 308 signals the image-sampler module 40 to power on. In theory, the predetermined threshold value should be equal to zero, but in practice, the predetermined threshold value is set a little greater than zero because of test errors. When the value of the difference-frequency signal is less than or equal to the predetermined threshold value, the first comparator 308 signals the display module 60 to display the “error” message.
The image-sampler module 40 includes a sampler 402, a processor 404, a first store unit 406. The sampler 402 is used for capturing the image of the contact fingers 902, converting the image to the digital image. The processor 404 is used for optimizing the digital image, such as enhancing an edge of the digital image and compressing the digital image. The first store unit 406 is used for storing the digital image after the digital image has been optimized.
A processing method used by the sampler 402 to generate the digital image includes following steps: capturing an image of the contact fingers 902; converting the image to grayscale digital signals; generating a two-dimension grayscale image with a plurality of pixels; giving black color to pixels that are greater than the predetermined threshold value, and giving white color to the rest pixels.
The image-analyzer module 50 includes a second store unit 502, an analyzer 504, and a second comparator 506. The second store unit 502 is used for storing the predetermined reference data corresponding to contact fingers 902 with no faults therein. The analyzer 504 is used for analyzing the digital image to obtain analyzed data. The second comparator 506 is used for calculating difference data between the analyzed data and the reference data in the second store unit 502, and obtaining a conclusion whether there are faults in the contact fingers 902 based on the difference data.
An analyzing method based on mathematical morphology is used by the analyzer 504. Three kinds of operations of the mathematical morphology are used for analyzing the digital image. A first kind of operation is an erosion operation including the following steps: decomposing the digital image through a series of structure elements with a specific shape; setting pixel values within each structure element to a minimum value of a pixel neighborhood. A second kind of operation is a dilation operation including the following steps: decomposing the digital image through a series of structure elements with a specific shape; setting pixel values within each structure element to a maximum value of a pixel neighborhood. The third kind of operation is a morphological opening operation that is composed of a dilation operation and an erosion operation followed by the dilation operation.
The display module 60 is used for displaying information of the contact fingers 902, such as whether there are faults, then proceed to point out what they are and where they are according to the conclusion. The display module 60 is also used for displaying the “error” message indicating that the PCB 90 is not detected by the detection module 30.
As mentioned above, the image of the contact fingers 902 of the PCB 90 is captured by the contact finger test apparatus 25 using an alternating magnetic field. Furthermore, the image is processed by the contact finger test apparatus 25 automatically. Therefore, by using the contact finger test apparatus, test accuracy can be improved and test time can be shortened.
Referring to
The osillator 302 produces a first alternating magnetic field at the first frequency toward the PCB 90 (step S701).
The detector 304 detects the second frequency of the second alternating magnetic field after the contact fingers 902 is impacted by the first alternating magnetic field, and calculating the discrepancy between the first frequency and the second frequency, and generates the difference-frequency signal accordingly (step S703).
The amplifier 306 amplifies the difference-frequency signal (step S705).
The first comparator 308 compares the value of the difference-frequency signal, after the difference-frequency signal has been amplified, with a predetermined threshold value that is predetermined (step S707). If the value of the difference-frequency signal is less than or equal to the predetermined threshold value, the procedure goes to step S709. If the value of the difference-frequency signal is greater than the predetermined threshold value, the procedure goes to step S711.
The first comparator 308 signals the display module 60 to display the “error” message (step S709).
The sampler 402 captures the image of the contact fingers 902, and converts the image to the digital image (step S711).
The processor 404 optimizes the digital image (step S713).
The first store unit 406 stores the digital image after the digital image has been optimized (step S715).
The analyzer 504 analyzes the digital image to obtain analyzed data (step S717).
The second comparator 506 calculates difference data between the analyzed data and the predetermined reference data stored in the second store unit 502, and obtains a conclusion whether there are faults in the contact fingers 902 based on the difference data (step S719).
The display module 60 displays information of the contact fingers 902 according to the conclusion (step S721).
It should be emphasized that the above-described preferred embodiment, is merely a possible example of implementation of the principles of the invention, and is merely set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and be protected by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 200610157542.5 | Dec 2006 | CN | national |
