Title of Invention

PRINTED CIRCUIT BOARD TESTING APPARATUS

Abstract

A PCB testing apparatus comprising: a bed of nails, an electronic module, and a testing tool consisted of a plurality of testing boards, a plurality of testing probes protrude out of the testing tool so as to be connected to the contact points of the circuit board to be tested, and to spring probes of a bed of nails, respectively; the testing probes are arranged with a certain slope in response to the contact points of the circuit board to be tested, the testing probes of the testing tool facing the bead of nails are equidistantly arranged, so that density of testing probes per unit area is increased without changing interval between the testing probes.

Full Text

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to printed circuit board (PCB) testing field, and more particularly to a PCB testing apparatus, wherein the density of testing probes per unit area is increased without changing interval between the testing probes. Description of the Prior Arts The printed circuit board is normally to be tested by a testing machine comprising a testing tool 1, a bed of nails 2 and an electronic module 4. The testing tool 1 includes a plurality of testing boards 10 which are combined together by connecting member according to needs, so as to obtain a desired slope of the testing probe 11. The testing probes 11 at the Y side are arranged in an equal matrix form, with reference to Fig. 2. The distance between the neighboring testing probes 11 is A, and the diagonal distance is C (C must be greater than A). Nowadays, the circuit board is becoming more and more precise, so this arrangement of the testing probes 11 is nearly unable to meet the demand of testing the modem circuit board, since the more precise circuit board, the more precise arrangement of the testing probes should be. Another method is to add another set of testing probes in the space between the neighboring probes, and the interval thereof is A/2, but this method is applicable only, by using small testing probes. Although this method increased the number of testing probes per unit area, the l shortened interval increases the difficulties in production, and the smaller the probes, the higher the production cost. Besides, the shortened interval increased the possibility of electric contact between the testing probes. FIG. 2 shows a conventional arrangement of the testing probes. The conventional arrangement of 7 testing probes cannot be displayed so close as the honeycomb arrangement of the present invention. If the arrangement of 7 testing probes are displayed too close, the spring probes and the testing probes shoould be very thin. It is very expensive to manufacture the very thin spring probes or the very thin testing probes. If the arrangement of the testing probes is too close, the electric contact between the neighbor testing probes will occur. Then the testing result will be wrong.. The present invention has arisen to mitigate and/or obviate the afore-described disadvantages. SUMMARY OF THE INVENTION The primary objective of the present invention is to provide a PCB testing apparatus comprising: a testing tool consisted of a plurality of testing boards, and a plurality of testing probes are distributed on the respective testing boards and located in response to contact points of.a circuit board to be tested, both ends of the respective testing probes protrude out of the testing tool so as to be connected to the contact points of the circuit board to be tested, and to spring probes of a bed of nails, respectively. The respective testing probes connected to the contact points of the circuit board to be tested are arranged with a slope of about 2 15 degrees to 10 degrees whereas the testing probes at the side of the testing tool facing the bed of nails are equidistantly arranged. Thus the interval between the testing probes 11 at the side of the testing tool 1 in contact with the circuit board is amplified by about 9mm due to the arrangement of the testing probes in a slope. Another objective of the present invention is to increase the number of testing probes per unit area by reducing the distance between the neighboring testing probes (indicated by the dotted line in Fig. 2), by disposing another testing probe 11' at the diagonal line of the original testing probes 11. Another objective of the present invention is to provide a PCB testing apparatus which further includes a bed of nails and an electronic module, wherein the bed of nails is provided with the spring probes, both ends of the respective spring probes protrude out of the bed of nails so as to be connected to the testing probes of the -testing tool and to the contact points of the electronic module, a plurality of contact points are disposed at an end of the electronic module, and another end of the electronic module is connected to CPU of a testing machine, the spring probes on the bed of nails are equidistantly distributed, and the contact points of the electronic module are equidistantly arranged. The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purpose of illustrations only, the preferred embodiment in accordance with the present invention. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Fig. 1 shows a cross sectional view of a PCB testing apparatus; Fig. 2 shows distribution of the conventional testing probes at the side of the testing tool opposite the bed of nails; Fig. 3 shows distribution of the testing probes at the side of the testing tool opposite the bed of nails in accordance with the present invention. Fig. 4 shows a cross sectional view of a PCB testing apparatus with deflection; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figs. 1 and 3, a PCB testing apparatus in accordance with the present invention comprises a testing tool 1, a bed of nails 2 arid an electronic module 4. The testing tool 1 includes a plurality of testing boards 10, and a plurality of testing probes 11 are arranged on the testing boards 10 so as to be connected to the contact points of the circuit board to be tested. Both ends of the respective testing probes 11 protrude out of the testing tool 1 so as to be connected to the contact points 30 of the circuit board 3 to be tested, and to the spring probes 20 of the bed of nails 2, respectively (X side of the testing tool is used to contact the circuit board to be tested and Y side of the testing tool is used to contact the bed of nails). The respective testing probes 11 are arranged with a 4 slope of approximately 15,degree to 10 degree in response to the contact points of the circuit board to be tested wherein a maximum deflection of 9mm is achieved thus amplifying the interval between the said testing probes (11) at the X side of the testing tool (1). The improvements of the present invention are explained as follows: Referring to fig. 1 and 4 the testing probes 11 at the Y side of the testing tool 1 are equidistantly arranged (the interval between the neighboring testing probes 11 is A). Besides, both ends of the respective spring probes 20 protrude out of the bed of nails 2 so as to be connected to the testing probes 11 and to the contact points at an end of the electronic module 4. A plurality of contact points 40 are disposed at an end of the electronic module 4, and another end of the electronic module 4 is connected to the CPU of the testing machine. The spring probes 20 on the bed of nails 2 are equidistantly arranged (the interval between the neighboring spring probes 20 is A), and the contact points 40 of the electronic module 4 are equidistantly arranged. The distance between two neighbouring contact points 40 of the electronic module 4 is defined as "A". With reference to Figs. 2 and 3, the interval between the neighboring testing probes 11 is A, since the diagonal distance C of the prior art (as shown in Fig. 2) is larger than A, the density of testing probes per unit area in accordance with the present invention (as shown in Fig. 3) is obviously greater than that, of the prior art (as shown Fig. 2) and the interval testing probes is still A. 5 The slope of the testing probe is approximately 15 degree to 10 degree. When the slope of the testing probe is 15 degree, the deflection (D) of the upper end of the testing probe is larger. When the slope of the testing probe is 10 degree, the deflection (D) of the upper end of the testing probe is smaller. (If the slope of the testing probe is too large, the testing result becomes unstable.) If the diameter of the testing probe is 0.25 mm to 0.40 mm, the maximum deflection (D) is 9 mm. If the slope is zero, the distance between two testing probes is defined as "A". When the slope of one testing probe is zero but the slope of the neighbor-testing probe is not zero, the distance between two upper ends of two neighbor-testing probes is A+D. The distance between two neighbor contact points 40 of the electronic module 4 is also defined as "A" as mentioned above. FIG. 3 shows 7 testing probes arranged in a honeycomb shape of the present invention. The honeycomb arrangement of the present invention is attained by disposing another testing probe 11 at the diagonal line of the original testing probes 11, giving a honeycomb arrangement. The distance between two lower ends of two neighbor testing probes is defined as "A". This kind of arrangement of the testing probes allows the distance between two lower ends of every two neighbouring testing probes to be the same. The honeycomb arrangement of the present invention allows a higher density of the testing probes per unit area, but the distance between two lower ends of two neighbor testing probes are the same as "A" which does not increase the length of the distance. 6 Thereby, the present invention can increase the density of the testing probes per unit area v/ithout changing the original interval between the testing probes. While we have shown and described various embodiments in accordance with the present invention, it should be clear to those skilled in the art that further embodiments may be made without departing from the scope of the present invention. 7 WE CLAIM: 1. A printed circuit board testing apparatus (Fig. 4 & 3) comprising: a testing tool (1) consisted of a plurality of testing boards (10), a plurality of testing probes (11) distributed on the said respective testing boards (10) and located in response to contact points (30) of a circuit board (3) to be tested, both ends of the said respective testing probes (11) protrude out of the said testing tool (1) so as to be connected to the said contact points (30) of the said circuit board (3) to be tested, and to said spring probes (11) of a bed of nails (2), respectively; characterized in that another testing probe (11') is disposed at the diagonal line of the original testing probes (11) thus increasing the number of said testing probes (11), giving a honeycomb shape to the arrangement of the said testing probes (11), which allows the distance between two lower ends of every two neighbouring said testing probes (11) to be the same, thus, the density of testing probes per unit area is increased without changing interval between the said testing probes (11); further the said respective testing probes (11) are arranged with a slope of 15 degrees to 10 degrees in response to the said contact points (30) of the said circuit board (3) to be tested wherein a maximum deflection of 9mm is achieved thus amplifying the interval between the said testing probes (11) at the X side of the said testing tool (1); 2. The printed circuit board testing apparatus as claimed in claim 1 further including the bed of nails (2) and an electronic module (4), wherein the bed of nails (2) is provided with the spring probes (11), both 8 ends of the said respective spring probes (11) protrude out of the said bed of nails (2) so as to be connected to the said testing probes (11) of the said testing tool (1) and to the contact points (40) of the said electronic module (4), a plurality of the said contact points (40) are disposed at an end of the said electronic module (4), and another end of the said electronic module (4) is connected to CPU of a testing machine, the said spring probes (11) on the said bed of nails (2) are equidistantly distributed, and the said contact points (40) of the said electronic module (4) are equidistantly arranged. A PCB testing apparatus comprising: a bed of nails, an electronic module, and a testing tool consisted of a plurality of testing boards, a plurality of testing probes protrude out of the testing tool so as to be connected to the contact points of the circuit board to be tested, and to spring probes of a bed of nails, respectively; the testing probes are arranged with a certain slope in response to the contact points of the circuit board to be tested, the testing probes of the testing tool facing the bead of nails are equidistantly arranged, so that density of testing probes per unit area is increased without changing interval between the testing probes.

Documents:

00793-kol-2004 abstract.pdf

00793-kol-2004 claims.pdf

00793-kol-2004 correspondence.pdf

00793-kol-2004 description(complete).pdf

00793-kol-2004 drawings.pdf

00793-kol-2004 form-1.pdf

00793-kol-2004 form-18.pdf

00793-kol-2004 form-2.pdf

00793-kol-2004 form-26.pdf

00793-kol-2004 form-3.pdf

00793-kol-2004 form-5.pdf

00793-kol-2004 letters patent.pdf