JPH06130410A - Terminal connection structure of electronic parts - Google Patents

Abstract

PURPOSE:To provide a stable and high quality joint structure by preventing a joint between a liquid crystal side terminal and a substrate side terminal of a liquid crystal type large display device unit from breaking by a heat cycle in use. CONSTITUTION:A film carrier 32 with bare wires 33 and 34 is inserted between a liquid crystal side terminal 2 and a board terminal and a board of which front and rear sides are reversed to each other. First the liquid crystal side terminal and a film carrier lead are reflow-soldered. Then an intermediate product is reversed, and a lead of the film carrier 32 is aligned with the board side terminal, pressurized, heated, and reflow-soldered. The intermediate product is reversed again, fixed to a frame 11 with adhesive agent and then, using a jig, a film carrier lead near the liquid crystal terminal is bent by 90 deg. and a controlling board is fixed to the frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal joining structure for electrically connecting an electronic component and each terminal of a control board arranged vertically to the electronic component and capable of withstanding repeated stress such as a thermal cycle. is there.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view showing a terminal joining structure of a conventional electronic component. In the figure, 1 is a liquid crystal panel as an electronic component constituting a liquid crystal display device, and 2 is a liquid crystal panel 1 for receiving an electric signal. Side electronic component side terminals, 2a is a preliminary solder applied to the terminal 2 in advance, and 3 is a flexible substrate in which a good electrical conductor (copper) pattern 6 through which an electric signal flows is sandwiched between a base film 4 and a cover film 5. , 7 are terminals on the side of the control board for deriving an electric signal, and 7a is a preliminary solder provided on the terminal 7 in advance. FIG. 10 is a perspective view showing a display unit 20 having the above liquid crystal panel structure, and 3a is wiring on the substrate 3 led from the driver IC 12, and has terminals 7 on the flexible control substrate 3. Reference numeral 12 is a driver IC mounted on the substrate 3, and 11 is a frame that forms the basis of the display unit 20. The display unit 20 is shown in FIG.
As shown in, a plurality of them are arranged vertically and horizontally and stacked. At this time, the liquid crystal panel 1 side is used as a front side display surface, and the flexible substrates 3 are arranged so that the upper and lower surfaces are placed to form a large screen display device. At this time, it is desirable that the gaps 21 and 22 between the display units 20 are as small as possible in terms of image quality. Therefore, the joint lengthwise dimension drawing 9
B is required to be extremely small. Further, since the terminals 2 are output from the pixels 1a in order to control a large number of red, green, and blue pixels of the liquid crystal panel 1, one unit has a large number of terminals 2 after all. Further, a large number of terminals 7 of the substrate 3 on which the driver ICs for controlling the pixels are mounted are connected to the respective terminals 2 of the liquid crystal panel 1 by soldering at a high density between XX in FIG. As many solder joints as the number of pixels are made. The liquid crystal panel 1 is fixed to the front surface of the frame 11, and the substrate 3 on which the driver IC 12 is mounted is fixed to the upper surface and the lower surface of the frame 11.

Next, the operation will be described. First, in order to fix the liquid crystal panel 1 vertically to the control substrate 3, the terminals 2 and 7 on the liquid crystal panel 1 side are brought close to each other,
The terminals 2 and 7 are positioned vertically and without any positional deviation in the front, rear, left and right. Next, the terminals 2 and 7 are heated with a soldering iron. As a result, the spare solder 2a, 7a
Melts and both terminals 2, 7 are joined by soldering between the corners. The cover film 5 is removed from the terminals of the substrate 3 to which the soldering is applied.

[0004]

Since the conventional terminal joining structure for electronic parts is constructed as described above, the terminals of the flexible substrate 3 are fixed by the resin base film 4 on one side. Therefore, during use, a large thermal stress acts on the above-mentioned joint (soldered portion) due to the difference in the coefficient of thermal expansion between the liquid crystal panel 1 as an electronic component and the substrate 3, and the solder portion is ruptured by the repeated thermal stress. There was a problem such as doing. That is, the joints were dense and the joints had an inter-corner shape. There is a problem in that, while the amount of solder is limited and the size of the corners cannot be increased, as a result of the fact that a structure with a high safety factor cannot be adopted, a fracture accident of the soldered part may occur. It was

The present invention has been made in order to solve the above problems, and makes it possible to inexpensively provide a terminal joining structure for an electronic component which has sufficient strength against thermal stress during operation of the electronic component. The purpose is to get.

[0006]

According to the present invention, there is provided a joint structure for an electronic component, comprising a film carrier having a bare wire portion at both ends at the same pitch as a liquid crystal terminal as the electronic component, the electronic component terminal and the substrate side terminal pitch. They are arranged in the middle of the same board-side terminal board, and at this time, the electronic component terminals and the terminals of the board-side terminal board are arranged on the same plane. The film carrier does not need to be a single terminal for connecting the terminals, and may be appropriately divided into a plurality of terminals. Position the film carrier so that the bare wire of the film carrier overlaps all the terminals on the electronic component terminals and at the same time the bare wire of the film carrier overlaps all the terminals on the terminals of the board-side terminal board. adjust. After that,
The electronic part terminal and the terminal part of the film carrier bare wire part,
For example, reflow soldering is done with a heat tool. At this time, flux is applied as needed. After that, the next film carrier is placed on the terminals of the electronic component and the terminals of the board terminal board, and reflow soldering is performed in the same manner as above.
After all the film carriers are soldered to one side of the electronic component, the film carriers are reflow-soldered to the terminals on the opposite side. Then, the front and back of the electronic component are reversed. After that, while positioning the film carrier and the board terminal, the film carrier bare wire portion and the board terminal are overlapped and reflow soldered. After completing the reflow soldering of all terminals, integrated electronic parts,
Flip the film carrier and substrate again. The frame is fixed to the liquid crystal as an electronic component with an adhesive. After that, the bare portion of the film carrier near the soldering portion on the electronic component side is bent 90 ° and fixed to the frame.

According to another invention, the portion of the film carrier to be overlapped with the board-side terminal and reflow-soldered has a structure in which the resin portion is left at the tip of the bare wire portion when the film carrier is punched out. , Solder with the board terminal and resin part.

According to still another aspect of the invention, a silicone resin is applied to the bare wire portion of the film carrier and the terminal portion and the lead wire which are reflow-soldered.

[0009]

The board-side terminal board having the same pitch and width as the board-side terminals according to the present invention, when the electronic component-side terminal and the bare wire portion of the film carrier are overlapped and reflow-soldered, the board-side terminal board and The positioning of the film carrier has an effect of accurately positioning the terminal and the bare line portion of the film carrier when the film carrier is soldered to the electronic component side terminal and then inverted, and a regular substrate is arranged. Since the film carrier of the present invention has the reflow soldering structure of the lap joint of the electronic component side terminal and the board side terminal respectively, the reliability of the joint is improved, at the same time mechanization is achieved, and a large number of terminals are reflow soldered Therefore, the reliability of the joint is further improved, and the number of joints is doubled, but the productivity can be improved. The bare lead portions at both ends of the film carrier have the function of relieving thermal stress. Before the board side terminal and the film carrier bare wire section are overlaid and reflow soldered, the film carrier is overlaid on the electronic component terminal and reversal soldered and then inverted, so that the film carrier bare wire section and the board side terminal section can be seen from the outside. Therefore, there is an effect that the quality of soldering can be visually confirmed and an effect that even if the fine lead wire in the substrate is broken, it can be repaired later.

The resin left at the tip of the film carrier soldered to the board-side terminal in the second aspect of the invention can accurately hold the tip pitch of the film carrier, so that a pitch error may occur and the other terminals may be damaged. It has the effect of eliminating the trouble of being connected. Further, since the resin portion at the tip is soldered, the bare wire portion of the film carrier can be taken longer, which has the effect of strengthening the heat cycle.

Applying the silicone resin to the bare wire portion of the film carrier in the third aspect of the invention has the function of insulating the terminal portion. However, if this resin is hardened, it means that the film carrier has a large thermal expansion, and it is meaningless to provide the film carrier with a bare wire portion. In this respect, since the silicone resin has a proper flexibility without solidifying, it has the function of not obstructing the fine movement of the bare leads of the film carrier.

[0012]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1 to 6, 1 is a liquid crystal panel as an electronic component, 31a is a board terminal board having the same terminal pitch as the control board, and the terminals are the reverse of the normal board terminals 31. Originally, the driver IC 1 is provided on the control board 31.
It is equipped with 2. Terminal 7 of this driver IC 12,
7a and the terminal of each pixel 1a as a liquid crystal panel are connected, and the film carrier 32 is connected between each terminal. First, the terminals 2 of the liquid crystal panel as an electronic component and the terminals 7 of the control board are positioned. A film carrier 32 is placed on top of it, and each terminal and bare wire lead 3
Accurately position 3,34. Thereafter, as shown in FIG. 5, the terminals 2 and 2a of the liquid crystal panel as an electronic component and the bare film carrier portions 33 and 33a of the liquid crystal panel are pressurized and reflow-soldered with a heat tool, for example. At this time, a flux may be used if necessary. Similarly, the film carrier bare wire portion 33 is soldered to the liquid crystal panel terminal 2 as an electronic component. After that, the film carrier bare wire portion is soldered to the terminal of the liquid crystal panel as the electronic component on the opposite side. FIG. 2 is a diagram showing this intermediate finished product. Next, the position of the control board 31 on which the driver IC is mounted is adjusted so that the film carrier lead portion 34 and the control board terminal portion 7 of the electronic component in which the film carrier 32 is previously soldered are inverted are accurately overlapped. To do. After that, the one shown in FIG. 2 is turned upside down, and the electronic parts soldered to the film carrier are attached to the control board terminals 7
Then, as shown in FIG. 6, the film carrier bare wire portions 34 and 34a and the control board terminal portions 7 and 7a are overlapped and reflow soldered. A perspective view of this intermediate finished product is shown in FIG. The intermediate product shown in FIG. 3 is turned upside down and placed on a flat surface, and the frame 11 is bonded to the liquid crystal panel 1 as an electronic component with an adhesive. Thereafter, a bare wire portion of the film carrier in the vicinity of the electronic component terminals is bent 90 ° with a jig (not shown), and at the same time, the control board is fixed to the frame. The completed drawing is shown in FIG.

Example 2. Next, a second embodiment of the present invention will be described with reference to the drawings. In FIG. 5, reference numeral 32 denotes a film carrier, which has bare wire leads 33 and 33a on both sides. The leads 33, 33a are soldered to the electronic component terminals 2, 2a. Further, as shown in FIG. 7, the resin 36 remains on the tips of the other leads. This lead 33, 33a
Are soldered to the terminals 7 and 7a of the control board 31. In FIG. 7, 31 is a control board, and 7 and 7a are terminals on the control board side. 32 is a film carrier, 34,
Reference numeral 34a is a lead soldered to the control board side terminal. 36 is the resin left on the tip of the lead 34. The lead on the back surface of the resin left uncut and the control board lead are overlapped and heated from above the resin by the heat tool 35, and reflow soldering is performed. At this time, a flux may be used if necessary.

Next, the operation of the second embodiment will be described. Example 1
As described above, the film carrier 32 and the board terminal board 31a are arranged on both sides of the liquid crystal panel terminal centering on the liquid crystal panel as an electronic component. At this time, if the ends of the leads on the film carrier substrate are opened, the leads may be caught during alignment, resulting in uneven lead pitches on the film carrier substrate side, causing short circuits such as bridges. The resin of the part is not separated but left as shown in FIG. As a result, the lead pitch on the substrate side of the film carrier does not shift even if objects hit or rub against each other. Therefore, the board side terminal and the film carrier board side lead can be accurately positioned. Then, after positioning, pressure and heat reflow soldering are applied from above the resin with the heat tool 35.

Example 3. Next, a third embodiment of the present invention will be described with reference to the drawings. In FIG. 8, reference numeral 33 indicates a lead wire of the film carrier reflow-soldered to the terminal of the electronic component. Reference numeral 2 is a terminal portion to which a lead wire is soldered, and 37 is a transparent silicon resin that electrically insulates the terminal portion 2 and the lead 33. Reference numeral 34 is a lead wire of the film carrier which is reflow-soldered to the terminal of the substrate, and 7 is a terminal portion which is reflow-soldered.

The operation of the third embodiment will be described below. The surface of the soldered portion between the terminal of the electronic component and the terminal on the substrate and the lead of the film carrier and the bare wire portion of the film carrier are made of metal and are not electrically insulated. If dust or dirt adheres to this area and becomes moist, short circuits between terminals and leads can be expected. Therefore, electrical insulation is provided by applying a transparent silicone resin to the terminals and the bare leads that have been soldered. 37 of FIG.
Is a silicone resin. If a resin that stiffens hard is used instead of silicone resin, it means that a material with a large coefficient of linear expansion has entered between the leads, causing the lead to break or the soldering part to come off due to the heat cycle during use. Occurs. On the other hand, since the silicone resin has an appropriate flexibility without solidifying, it does not interfere with the fine movement of the bare lead of the film carrier due to the heat cycle during use.

[0017]

As described above, according to the first aspect of the present invention, the electronic component and the control board terminal are soldered by the film carrier having the bare wire portion. Since the solder joint is not broken and the soldering work can be mechanized at the same time, a stable and highly reliable joint can be obtained. In addition, since the connection between the control board terminal and the bare film carrier lead wire can be seen from the outside of the unit, the quality of the joint can be visually inspected, and if the control board wiring pattern is broken, use a jumper wire to directly drive the driver. There is an effect that a defective product can be relieved by connecting to an IC terminal.

According to the second aspect of the invention, since the resin is left at the tips of the film carrier substrate leads to be soldered to the substrate terminals, and pressure and heat reflow soldering is applied from above the resin, the film carrier The lead pitch of the tip is unchanged, and there is an effect that it can be easily aligned with the board-side terminal. Also, since pressure and heat reflow soldering are applied from above the resin, there is an effect that the length of the bare lead wire at the tip of the film carrier can be made longer and the thermal stress can be relaxed.

Furthermore, according to the third aspect of the invention, since the silicon resin is applied to the soldering portions between the terminals of the electronic parts and the substrate and the film carrier lead wires, and the bare portions of the film carrier bare wires, the electrical conductivity is improved. Since the insulation can be achieved and the silicon resin is not firmly solidified, the fine movement of the bare lead wire of the film carrier due to the heat cycle during use is not restricted.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure during a process of assembling a terminal joining structure according to the present invention.

FIG. 2 is a perspective view showing a structure in the middle of an assembling process of the terminal joining structure according to the present invention.

FIG. 3 is a perspective view showing a structure in the middle of an assembling process of the terminal joining structure according to the present invention.

FIG. 4 is a perspective view showing a first embodiment of the present invention.

FIG. 5 is a perspective view showing a part of a joint portion according to the present invention.

FIG. 6 is a perspective view showing a part of a joint portion according to the present invention.

FIG. 7 is a side view showing a part of the joint portion according to the second embodiment of the present invention.

FIG. 8 is a perspective view showing a third embodiment of the present invention.

FIG. 9 is a side view showing a part of a conventional joint portion.

FIG. 10 is a perspective view showing a conventional joining structure.

FIG. 11 is a perspective view showing a large-sized liquid crystal display unit.

[Explanation of symbols]

 1 Liquid crystal panel 2 Liquid crystal panel side terminal 3a Wiring pattern 7 Board side terminal 11 Frame 12 Driver IC 31 Control board 32 Film carrier 33 Film carrier lead (bare wire) 34 Film carrier lead (bare wire) 36 Resin at the tip of lead 37 Silicone resin

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[Procedure amendment]

[Submission date] July 27, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

Since the conventional terminal joining structure for electronic parts is constructed as described above, the terminals of the flexible substrate 3 are fixed by the resin base film 4 on one side. Therefore, during use, a large thermal stress acts on the above-mentioned joint (soldered portion) due to the difference in the coefficient of thermal expansion between the liquid crystal panel 1 as an electronic component and the substrate 3, and the solder portion is ruptured by the repeated thermal stress. There was a problem such as doing. That is, the joint has a high density and the joint has a fillet shape.
Was. Joining while the amount of solder is limited and the size of the fillet cannot be increased, there are problems such as breakage of the soldered part as a result of the fact that a structure with a high safety factor cannot be adopted. It was

Claims (3)

[Claims] 1. In a joint structure of an electronic component side terminal and a substrate side terminal of a liquid crystal panel, a film carrier having a bare wire portion at both ends is arranged between the both terminals, and one of the bare wire portions is an electron. Soldered to the component side terminal and the other side to the board side terminal, respectively, and the liquid crystal panel and the board are arranged so that the bare wire part of the film carrier and the connection part of the board side terminal can be seen from the outside. A terminal joining structure for electronic components, characterized in that the wire portions are bent substantially at right angles and are fixed to the respective frames. 2. The bare line portion of the film carrier connected to the board-side terminal is connected at its tip with resin, and the board-side terminal is pressed and heated by reflow soldering from above the resin. The terminal joining structure for an electronic component according to claim 1. 3. The terminal joining structure for an electronic component according to claim 1, wherein a silicone resin is applied to the bare wire portion of the film carrier and the terminal portion to which each terminal is joined and the bare wire portion.