TWI411841B - Lcd module and method for measuring contact resistances between circuit boards therein - Google Patents

Abstract

An LCD module includes a flexible printed circuit (FPC), a printed circuit board (PCB), a first pad and a second pad. The FPC has a first conductive line, and the PCB has a second conductive line. The second conductive line is bonded to the first conductive line. The first pad is electrically connected to the first conductive line, and the second pad is electrically connected to the second conductive line. The first pad and the second pad are provided for determining if the second conductive line is bonded to the first conductive line. A method for measuring contact resistances between circuit boards in an LCD module is also disclosed herein.

Description

Liquid crystal display module and method for measuring contact impedance between circuit boards thereof

The present invention relates to a liquid crystal display module, and more particularly to a structure for measuring contact impedance between circuit boards in a liquid crystal display module.

Generally, when manufacturing a liquid crystal display module, a printed circuit board (PCB) must be closely bonded to a flexible printed circuit (FPC) by a conductive adhesive (such as an anisotropic conductive adhesive, or ACF adhesive). Pressing in order to allow the signal to pass smoothly between the printed circuit board and the flexible circuit board.

However, it is conventionally known to determine whether or not the two boards are actually pressed together, and only by the indentation or the amount of glue overflowed therebetween, the result of the determination is often inaccurate. In addition, since it is often necessary to rely on manpower to complete the indentation or the amount of glue that is involved in the process, it is impossible to perform automated inspection using the machine, and it is also labor intensive.

SUMMARY OF THE INVENTION The object of the present invention is to provide a liquid crystal display module and a method for measuring contact impedance between circuit boards thereof, thereby improving the quality of bonding between the circuit boards and ensuring a good press-fit situation between the circuit boards.

One aspect of the present invention relates to a liquid crystal display module including a flexible circuit board, a printed circuit board, a first bonding pad, and a second bonding pad. The flexible circuit board has a first wire, and the printed circuit board has a first The two wires are electrically connected to the first wires of the flexible circuit board. The first pad is electrically connected to the first wire, and the second pad is electrically connected to the second wire, wherein the first pad and the second pad are used for power supply contact to determine whether the second wire is indeed connected to the first wire Electrically bonded.

Another aspect of the present invention relates to a liquid crystal display module including a flexible circuit board, a printed circuit board, a plurality of first pads, and a plurality of second pads. The flexible circuit board has a plurality of first wires, and the printed circuit board has a plurality of second wires, wherein the second wires of the printed circuit board are respectively electrically coupled to the first wires of the flexible circuit board. The first pad is electrically connected to the first wire, and the second pad is electrically connected to the second wire, wherein the first pad and the second pad are used for power supply contact to measure the second The contact resistance between the wires after being electrically connected to the first wires, respectively.

A further aspect of the present invention relates to a method for measuring a contact impedance between circuit boards in a liquid crystal display module, comprising: providing a first pad and a second pad; electrically connecting the first pad to the first pad a first wire on the flexible circuit board; electrically connecting the second pad to a second wire on a printed circuit board; electrically bonding the second wire of the printed circuit board and the first wire of the flexible circuit board; The contact resistance between the second wire and the first wire after the second wire is electrically connected is measured through the first pad and the second pad.

Still another aspect of the present invention relates to a liquid crystal display module including a printed circuit board, a flexible circuit board, a first bonding pad, and a second bonding pad. The printed circuit board has a first wire portion and a second wire portion, wherein the first wire portion and the second wire portion are not connected to each other. Soft The circuit board has a third wire, wherein the third wire is electrically coupled to both the first wire portion and the second wire portion. The first pad is electrically connected to the first wire portion or the second wire portion, and the second pad is electrically connected to the third wire.

According to the technical content of the present invention, the method for measuring the contact impedance between the liquid crystal display module and the circuit board therein can be used to accurately determine whether the circuit board has a good pressure by measuring the contact impedance between the boards. And can improve the reliability of the liquid crystal display module.

FIG. 1A is a schematic view showing a circuit board press-fit in a liquid crystal display module according to an embodiment of the invention. The liquid crystal display module comprises a flexible circuit board (FPC) 110 and a printed circuit board (PCB) 120, wherein the flexible circuit board 110 is provided with a first wire 112, and the printed circuit board 120 is provided with a second wire 122, and a second The wire 122 is electrically coupled to the first wire 112. In addition, the printed circuit board 120 can be provided with pads A, B, C and D, wherein the pad A is electrically connected to the first wire 112, and the pad C is electrically connected to the second wire 122 for respectively for detecting and detecting The device (such as a probe or a three-meter electric meter or a related detecting device) is electrically contacted to determine whether the second wire 122 is electrically connected to the first wire 112, and the pads B and D are respectively associated with the pad A and The C electrical connection is also used for electrical contact with the detecting device. In addition, the above-mentioned solder pads may be disposed on the printed circuit board 120 or both on the flexible circuit board 110, or on the printed circuit board 120 and the flexible circuit board 110, respectively, depending on the actual design or use.

Furthermore, the second wire 122 can be further divided into a first portion 122a and a The second portion 122b, wherein the first portion 122a and the second portion 122b of the second wire 122 are not connected to each other, and both are electrically coupled to the first wire 112 at the same time. In the present embodiment, the second wire 122 is divided into the first portion 122a and the second portion 122b along the direction of the first wire 112; that is, the first portion 122a and the second portion 122b are along the first wire 112. Direction configuration. In addition, the pad C is selectively electrically connected to the first portion 122a or the second portion 122b of the second wire 122. In this embodiment, the pad C is electrically connected to the second portion 122b of the second wire 122. In this way, if the probe or the three-meter is electrically contacted with the pads A and C (or B and D), a measuring circuit can be formed, thereby judging whether the second wire 122 is indeed A wire 112 is electrically connected, or the contact resistance between the second wire 122 and the first wire 112 is electrically connected to determine the state in which the flexible circuit board 110 is pressed against the printed circuit board 120.

Fig. 1B is a side view showing the pressing of the printed circuit board and the flexible circuit board as shown in Fig. 1A. As shown, the first conductive line 112 on the flexible circuit board 110 is simultaneously bonded to the first portion 122a of the second conductive line 122 on the printed circuit board 120 by a conductive adhesive (eg, an anisotropic conductive adhesive, abbreviated as ACF adhesive) 130. The second portion 122b is electrically joined. FIG. 1C is a schematic diagram showing an equivalent circuit after the printed circuit board and the flexible circuit board are pressed as shown in FIG. 1A. The resistance R can be regarded as the contact resistance between the first wire 112 and the second portion 122b of the second wire 122 after being electrically joined, and can be formed by connecting the pads A, B, C and D. The measurement loop is measured by it.

Fig. 1D is a circuit diagram showing the connection of the equivalent circuit shown in Fig. 1C to form a measuring circuit. Where R _W is the line impedance, and R _T is the contact resistance between the first wire 112 and the second wire 122 after being electrically joined. As shown, after the pads A, B, C, and D are connected to the first wire 112 and the second wire 122 to form a measurement loop, the values of the voltmeter 140 and the ammeter 150 can be read. The contact resistance R _T between the first wire 112 and the second wire 122 after being electrically joined.

2 is a schematic diagram showing electrical bonding of a second wire on another printed circuit board to a first wire on a flexible circuit board in accordance with an embodiment of the present invention. Compared with FIG. 1 , the second wire 222 in this embodiment is divided into a first portion 222 a and a second portion 222 b along a direction perpendicular to the first wire 212 (ie, the X direction); that is, the first The portion 222a and the second portion 222b are disposed along the X direction perpendicular to the extending direction of the first wire 212. In addition, pads E and F may be disposed on the printed circuit board, wherein the pads E and F are electrically connected to the first portion 222a and the second portion 222b of the second wire 222, respectively, for use with the probe or the three The meter electrically contacts to determine whether the second wire 222 is indeed electrically coupled to the first wire 212.

FIG. 3 is a schematic view showing the pressing of a circuit board in a liquid crystal display module according to another embodiment of the present invention. Compared with FIG. 1A, a plurality of first wires 312 are disposed on the flexible circuit board 310, and a plurality of second wires 322 are disposed on the printed circuit board 320, and the first wires 312 and the second wires are respectively 322 is electrically coupled correspondingly. In addition, a plurality of pads A, B, C, and D may be disposed on the printed circuit board 320. The pads A are electrically connected to the first wires 312, and the pads C are electrically connected to the second wires 322, respectively. In addition, each of the second wires 322 is divided into the first portion as compared to FIG. 1A. A portion 322a and a second portion 322b are simultaneously electrically coupled to the first wire 312. Similarly, each of the second wires 322 may be divided into the first portion 322a and the second portion 322b along the direction of the first wire 312, or may be designed along the direction perpendicular to the first wire 312 (ie, the X direction). It is divided into a first portion 322a and a second portion 322b (as shown in FIG. 2). In this way, after the flexible circuit board is pressed into the printed circuit board, each of the first wire 312 and the second wire 322 thereon can be detected or measured to determine the compression between the two.

FIG. 4A is a schematic view showing the pressing of a circuit board in a liquid crystal display module according to still another embodiment of the present invention. Compared with FIG. 1A, the first wire 412 on the flexible circuit board 410 is designed to be similar to the inverted E-shaped configuration, and is electrically coupled to the corresponding second wires 422a, 422b, and 422c; that is, One of the three wires is connected to each other, and the other end is electrically coupled to the corresponding second wires 422a, 422b, and 422c, respectively. In addition, solder pads A, B, C, and D may be disposed on the printed circuit board 420, wherein the pads A and B are electrically connected to the second wires 422a and 422c, respectively, and the pads C and D are simultaneously connected to the second wires 422b. Electrical connection. In this way, a measuring circuit can be formed by electrically contacting the pads A, B, C, and D with a probe or a three-meter to form a measurement circuit, thereby discriminating the case where the flexible circuit board 410 is pressed against the printed circuit board 420. .

Fig. 4B is a side view showing the pressing of the printed circuit board and the flexible circuit board as shown in Fig. 4A. As shown, the first conductive line 412 on the flexible circuit board 410 is electrically coupled to the second conductive lines 422a, 422b, and 422c on the printed circuit board 420 by the conductive adhesive 430.

Similarly, the pads A, B, C, and D can be connected to the first wire 412 and the second wires 422a, 422b, and 422c to form a measurement circuit similar to that shown in FIG. 1D, and by reading the voltage. The value of the galvanometer is taken to obtain the contact resistance between the first wire 412 and the second wire 422a, 422b, and 422c after being electrically joined.

It should be noted here that the connection between the pad or pad and the wire described above can be after measuring the contact resistance between the boards, or after determining whether there is a positive bond between the wires on the board. Select it selectively. Furthermore, the above-mentioned solder pads may be disposed on the printed circuit board or both on the flexible circuit board according to actual design or use, or respectively disposed on the printed circuit board and the flexible circuit board.

FIG. 5 is a flow chart showing a method for measuring contact impedance between circuit boards in a liquid crystal display module according to an embodiment of the invention. Please refer to both Figure 1A and Figure 5. First, pads A (or B) and C (or D) are provided (step 502), wherein pads A and C are selectively disposed on printed circuit board 120 or flexible circuit board 110. Next, the pad A is electrically connected to the first wire 112 on the flexible circuit board 110 (step 504), and the pad C is electrically connected to the second wire 122 on the printed circuit board 120 (step 506). Furthermore, the second wire 122 on the printed circuit board 120 is electrically coupled to the first wire 112 on the flexible circuit board 110 (step 508). Then, the contact resistance between the second wire 122 and the first wire 112 after electrical connection is measured via the pads A and C (step 510). It should be noted here that the order of the above steps 504 and 506 can be adjusted according to the actual situation, and is not limited to the order shown in FIG.

In addition, in the step of electrically connecting the second wire 122 and the first wire 112 (step 508), the second wire 122 may be first divided into the first portion 122a and the second portion 122b, and then the first wire 122 A portion 122a and a second portion 122b are simultaneously electrically coupled to the first wire 112, and the pad C is more selectively coupled to the first portion 122a or the second portion 122b of the second wire 122.

In addition, please refer to Fig. 2 and Fig. 5 at the same time. If the second wire 222 is in the configuration shown in FIG. 2, two pads (eg, pads E and F) may be provided, and the pads are electrically connected to the second wires 222 correspondingly. A portion 222a and a second portion 222b are then used to measure the contact resistance between the first portion 222a and the second portion 222b of the second wire 222 after being electrically coupled to the first wire 212, respectively.

According to the embodiment of the present invention, the method for measuring the contact impedance between the liquid crystal display module and the circuit board can be used to accurately determine whether the circuit boards have good contact between the boards by measuring the contact impedance between the boards. The pressing can improve the reliability of the liquid crystal display module. In addition, automated inspections can be performed by detection or measurement devices, saving a lot of labor costs.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and any one of ordinary skill in the art to which the present invention pertains can be modified and retouched without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

110, 310, 410‧‧‧Soft circuit boards

112, 212, 312, 412‧‧‧ first conductor

120, 320, 420‧‧‧ Printed circuit boards

122, 222, 322, 422a, 422b, 422c‧‧‧ second conductor

122a, 222a, 322a‧‧‧ the first part of the second conductor

122b, 222b, 322b‧‧‧ the second part of the second conductor

130, 430‧‧‧ conductive adhesive

140‧‧‧ voltmeter

150‧‧‧ galvanometer

502~510‧‧‧Steps

FIG. 1A is a schematic view showing a circuit board press-fit in a liquid crystal display module according to an embodiment of the invention.

Fig. 1B is a side view showing the pressing of the printed circuit board and the flexible circuit board as shown in Fig. 1A.

FIG. 1C is a schematic diagram showing an equivalent circuit after the printed circuit board and the flexible circuit board are pressed as shown in FIG. 1A.

Fig. 1D is a circuit diagram showing the connection of the equivalent circuit shown in Fig. 1C to form a measuring circuit.

2 is a schematic diagram showing electrical bonding of a second wire on another printed circuit board to a first wire on a flexible circuit board in accordance with an embodiment of the present invention.

FIG. 3 is a schematic view showing the pressing of a circuit board in a liquid crystal display module according to another embodiment of the present invention.

FIG. 4A is a schematic view showing the pressing of a circuit board in a liquid crystal display module according to still another embodiment of the present invention.

Fig. 4B is a side view showing the pressing of the printed circuit board and the flexible circuit board as shown in Fig. 4A.

FIG. 5 is a flow chart showing a method for measuring contact impedance between circuit boards in a liquid crystal display module according to an embodiment of the invention.

310‧‧‧Soft circuit board

312‧‧‧First wire

320‧‧‧Printed circuit board

322‧‧‧second wire

322a‧‧‧The first part of the second conductor

322b‧‧‧Second part of the second conductor

Claims (21)

A liquid crystal display module comprising: a flexible circuit board having a first wire; a printed circuit board having a second wire electrically coupled to the first wire of the flexible circuit board; a solder pad electrically connecting the first wire; and a second pad electrically connected to the second wire, wherein the first pad, the first wire, the second wire, and the second pad form A test circuit, the first pad and the second pad are used for power supply detection to determine whether the second wire is electrically coupled to the first wire. The liquid crystal display module of claim 1, wherein the second wire is further divided into a first portion and a second portion, and the first portion and the second portion are simultaneously electrically coupled to the first wire. . The liquid crystal display module of claim 2, wherein the second pad is electrically connected to the first portion or the second portion of the second wire. The liquid crystal display module of claim 3, further comprising: a third bonding pad electrically connecting the second portion or the first portion of the second wire to the second bonding pad, wherein the first portion The second pad and the third pad are used for power supply contact to determine the first portion of the second wire and the Whether the second portion is electrically coupled to the first wire at the same time. The liquid crystal display module of claim 4, wherein the first bonding pad, the second bonding pad, and the third bonding pad are disposed on the printed circuit board. The liquid crystal display module of claim 1, wherein the first bonding pad and the second bonding pad are disposed on the printed circuit board or are disposed on the flexible circuit board. The liquid crystal display module of claim 1, wherein the first bonding pad and the second bonding pad are respectively disposed on the printed circuit board and the flexible circuit board. A liquid crystal display module comprising: a flexible circuit board having a plurality of first wires; a printed circuit board having a plurality of second wires, wherein the second wires of the printed circuit board are respectively associated with the flexible circuit board The first wires are electrically connected to each other; the plurality of first pads are electrically connected to the first wires; and the plurality of second pads are electrically connected to the second wires, wherein the plurality of wires are electrically connected a solder pad, the first wires, the second wires, and the second pads form a plurality of test loops, and the first pads and the second pads are used for power supply contact measurement The second wires are respectively associated with the The contact resistance between a wire after it is electrically bonded. The liquid crystal display module of claim 8, wherein each of the second wires is further divided into a first portion and a second portion, the first portion and the second portion of each of the second wires Portions are electrically coupled to one of the first wires at the same time. The liquid crystal display module of claim 9, wherein each of the second pads is electrically connected to the first portion or the second portion of one of the second wires. The liquid crystal display module of claim 10, further comprising: a plurality of third pads, each of the third pads electrically connecting the second pads to each of the second pads Measuring the second portion or the first portion of one of the wires, wherein the second pads and the third pads are for powering contact to measure the first portion of each of the second wires and The contact resistance between the second portion and one of the first wires after electrical bonding. The liquid crystal display module of claim 11, wherein the first bonding pads, the second bonding pads, and the third bonding pads are disposed on the printed circuit board. The liquid crystal display module of claim 8, wherein the first pads and the second pads are disposed on the printed circuit board or are disposed on the flexible circuit board. The liquid crystal display module of claim 8, wherein the first pads and the second pads are respectively disposed on the printed circuit board and the flexible circuit board. A method for measuring contact impedance between circuit boards in a liquid crystal display module, comprising: providing a first bonding pad and a second bonding pad; electrically connecting the first bonding pad to one of a flexible circuit board Electrically connecting the second bonding pad to a second wire on a printed circuit board; electrically bonding the second wire of the printed circuit board and the first wire of the flexible circuit board, such that the first The solder pad, the first wire, the second wire, and the second pad form a test loop; and the second wire and the second pad are electrically connected to the first wire via the first pad and the second pad Contact impedance between them. The measuring method of claim 15, wherein the step of electrically joining the second wire and the first wire further comprises: dividing the second wire into a first portion and a second portion; The first portion and the second portion are simultaneously electrically coupled to the first wire. The measuring method of claim 16, wherein the step of electrically connecting the second bonding pad to the second wire further comprises: electrically connecting the second bonding pad to the second wire The first part or the second part. The measuring method of claim 17, further comprising: providing a third bonding pad; electrically connecting the third bonding pad to the second portion of the second wire or the second bonding pad or The first portion; and measuring a contact resistance between the first portion and the second portion of the second wire electrically connected to the first wire via the second pad and the third pad, respectively. A liquid crystal display module comprising: a printed circuit board having a first wire portion and a second wire portion, the first wire portion and the second wire portion are not connected to each other; and a flexible circuit board having a third a wire, the third wire is electrically coupled to the first wire portion and the second wire portion; a first pad electrically connecting the first wire portion or the second wire portion; and a second pad Electrically connecting the third wire, wherein the first pad, The first wire portion, the second wire portion, the third wire and the second pad form a test loop, and the first pad and the second pad are used for power supply detection to determine the third wire Whether it is electrically engaged with the first wire portion and the second wire portion. The liquid crystal display module of claim 19, wherein the first wire portion and the second wire portion are disposed along an extending direction of the third wire. The liquid crystal display module of claim 19, wherein the first wire portion and the second wire portion are disposed along a direction perpendicular to a direction in which the third wire extends.