JPS6220396A - Electronic equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device, and particularly to an electronic device having a configuration in which a circuit member is connected to a printed circuit board using a conductive adhesive.

[Prior Art] In recent years, electronic desks and calculators (hereinafter referred to as calculators),
BACKGROUND ART In electronic devices such as liquid crystal watches, a structure in which a printed circuit board and electronic components or other circuit members such as printed circuit boards are bonded using a conductive adhesive has come to be used. Conductive adhesive is a composite of organic and inorganic substances, which is a mixture of a binder mainly made of synthetic resin such as epoxy resin and conductive particles (hereinafter referred to as conductive filler) mainly made of metal powder such as silver or lead. be. The conductive adhesive is sandwiched between the members to be connected, and heat and pressure are applied to activate the binder and cause it to conform to the surfaces of the members to be bonded. Thereafter, when the member cools down, the heat in the binder is released and the binder hardens.

[Problems to be Solved by the Invention] Figures 5(A) and 5(B) explain the bonding of old circuit parts with conductive adhesive. A printed circuit board provided with a circuit pattern made of metal foil, numerals 7 and 8 respectively indicate a conductive filler and a binder of the conductive adhesive 9.

FIG. 5(A) shows the state before heating and pressurization, and as shown in the figure, the conductive filler does not come into contact with the inner substrates 5 and 6 even when voltage is applied by the DC stabilized power source V. So,
Ammeter A does not touch, and the patterns on both boards are not conductive.

On the contrary, as shown in Fig. 5(B), when the binder 8 is applied to the inner substrate, hardened, and dried (without applying heat or pressure), the conductive filler 7 hardens and shrinks. It contacts the inner substrate 2 and does not provide conductivity.

Actually, the circuit members 7 are bonded using an apparatus as shown in FIG. In Figure 6, Ministry number 191”
A hot plate 19 is used for heating and pressurizing, and the hot plate 19 heats and presses the members on the support base 21 to bond them together. Here, a case is shown in which the printed circuit board 15 and the liquid crystal display l are bonded.

Liquid crystal display l is in order from 1-j, 1-1 polarized X plate 10.1
, a glass plate 11, a glass plate 12, a polarizing plate 13, and a reflecting plate 14. The liquid crystal is supported between the 12-glass plate 11 and the lower glass plate 12, and the lower glass plate 12 is formed with a circuit pattern of transparent electrodes for applying a −C display voltage to the liquid crystal. Pudding)・No1 (board 15 and one togaranu board 12Olil
The track patterns are glued together using a conductive adhesive 9.

7(A) is a sectional view taken along the line C- and C in FIG. 6 when heating and pressurizing are performed by the hot plate 19 ij. A plurality of circuit patterns 22 are formed on the lower glass plate 12-1-6 of FIG. 7(A), and these are connected to the circuit patterns 8a and 8b of the printed circuit board 151-. A tamper 20 made of rubber, rubber, etc. is formed at the tip of the hot plate 19, and -C heating and pressurization are performed through this damper 20. As shown in the same figure, heat
When + is applied, the binder 8 contracts due to heat and pressure, and the conductive filler 7 comes into contact with both the circuit patterns 8 a, 8 c and the circuit pattern 22, and the patterns become electrically connected.

However, since there is no pattern at the edges of the substrate 15 and the lower glass plate 12, the pressure of the damper 12 causes the deformation 1, 2 and uncured state until the substrate 15 comes into contact with the lower glass plate 12. Binder 8 is indicated by arrow P;
It flows out in the direction of Q. As a result, when the hot plate 19 is heated as shown in FIG.
The part that was bonded by the binder 8 peeled off, and the restoring force of the bony pudding I and substrate I5 caused cohesive fracture, resulting in 1. Mau. Therefore, circuit pattern 8
The adhesive force between C and 22 is always unstable.

As described above, the conventional connection using a conductive adhesive has a problem in that the adhesive force is not stable in the end region of the member to be connected to the printed circuit board.

[Level-L for solving the problems] The present invention solves the following problems as follows: lJ, printed circuit board +, = circuit members constituting the electric P circuit are connected using a conductive adhesive. In the electronic device having such a configuration, a configuration is adopted in which a dummy pattern is provided at the end of the printed circuit board to prevent the conductive adhesive from extruding.

[Function] As shown in FIG. 1(A), the end i=- of the printed circuit board 15' (7) forms a tammy pattern 23. As a result, the damper 20 of the heat m19 presses the printed circuit board 15' and the lower glass plate 12 in the end region in the same way as in other parts without bringing them into close contact with each other, so that the binder 8 flows out in the directions of arrows P and Q. There is enough binder left over without any residue. As a result, as shown in FIG. 1(B), the hot plate 19
Even when the temperature is increased, the binder 8 remains in the edge region for an amount of f-, so the adhesive force at the edge does not become unstable as in the conventional case, and all the circuit patterns to be connected are reliably connected. can do.

"Embodiments" The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 2 is a perspective view showing the external appearance of a calculator adopting the present invention.
In the figure, 93:1 is a liquid crystal display for displaying numerical data and calculation results. Furthermore, a solar cell is placed on the side of the liquid crystal display l to serve as a power source for electronic components housed inside. The front side of the liquid crystal display l and solar cell 2 is
In order to carry out the key human power, it is a resin panel made of polyester etc. with a Gie symbol printed on it. The panel 3 is glued to a frame 41 made of ABS polymeric material.

The connection structure between the liquid crystal display 1 and the internal printed circuit board;'li
is shown in FIG. 3 as a sectional view taken along the line A--A in FIG. 2 and at an angle of 1°. The liquid crystal display 1 and the printed circuit board 15' are housed in four parts 4a provided in an integrally formed frame 4. The liquid crystal display l and the printed circuit board 15 are bonded together using a conductive adhesive 9. Below the frame 4, reinforcing plates 16 and 17 made of a stair frame and the like are fixed by adhesive or other methods for reinforcement and electrostatic shielding.

Further, the F side of the device is covered with a back panel 18 made of the same material as the panel 3 described above.

The liquid crystal display l has the same structure as the liquid crystal display described above.
1. It consists of the same structural members as those described above.

The arrangement of the circuit pattern at the end of the printed circuit board 15' is
As shown in the figure. The printed circuit board 15' has a circuit pattern 8a for connection to the liquid crystal display l.

8C is provided. A dummy pattern 23 having substantially the same shape as the circuit patterns 8a and 8c is formed at the end of the printed circuit board 15'. This pattern 23 is provided to stabilize the contact force and is not connected to the circuit.

FIGS. 1A and 1B show how the printed circuit board 15' and the liquid crystal display l are connected using the apparatus shown in FIG. 6. FIG. 1 corresponds to a cross section taken along line BB in FIG. 2.

When heating and pressurizing are performed by the hot plate 19, a dummy pattern 23 is formed at the end of the printed circuit board 15'.
As shown in Figure (A)), it does not undergo elastic deformation and is compressed uniformly over the entire surface. Therefore, the binder 8 at the end does not slide out in the direction of the force indicated by the arrows P and Q as in the conventional case, and the binder 8 does not move out in the direction of the force shown by the arrows P and Q, and the binder 8 does not move out in the direction of the force shown by the arrows P and Q in the end region.
remain between.

Therefore, when the hot plate 19 is raised as shown in FIG. 1(B),
Since sufficient conductive adhesive remains in the edge area, only a small area of the solder at the edge of the printed circuit board 15' and the glass plate 12 will peel off due to cohesive failure. Therefore, the circuit pattern 1C near the edge of the substrate is reliably bonded to the circuit pattern of the liquid crystal display l.

Below 1. As shown in the figure, printed circuit boards and circuit components are conductive.
When making a connection using a 1F adhesive, the printed board and the circuit member can be reliably connected without causing poor connection performance due to cohesive failure caused by the end region of the board.

Although the connection between a liquid crystal display and a printed circuit board is described in Example 17 above, the technology of the present invention can also be applied to the connection between an integrated circuit and a printed circuit board, a solar cell and a printed circuit board, or a printed circuit board. Of course. Also,
The technology of the present invention is not limited to electric boxes, but can also be used for liquid crystal display.
It can be applied to various electronic devices such as , game electronic +i, and electronic translators.

[Effect] As is clear from the above description, according to the present invention, in an electronic device having a configuration in which concave path members of a printed circuit board 15 constituting an electric circuit are connected using a conductive adhesive, Since a configuration is adopted in which a dummy pattern is provided at the edge of the substrate to prevent the conductive adhesive from spilling out, low adhesion caused by cohesive failure at the edge of the substrate is prevented. L, ensure 2 even in the board edge area.
(It is possible to provide an excellent electronic device structure that allows connections between boards and circuit members.

[Brief explanation of the drawing]

Figures 1 (A) and (B) are cross-sectional views showing the adhesion of a printed circuit board and a circuit member according to the present invention, Figure 2 is a perspective view of the external appearance of a calculator adopting the present invention, and Figure 3 is the same as Figure 2. A-A of
4 is an enlarged view showing the circuit pattern of the printed circuit board according to the present invention from -1-, and FIG. 5 is a sectional view taken along the line.
A) and (B) are explanatory diagrams showing adhesion using conductive adhesive, Fig. 6 is a cross-sectional view showing the state of adhesion using conductive adhesive, and Fig. 7 (A) and (B) are respectively FIG. 3 is a cross-sectional view showing the drawbacks caused by adhesion using a conventional non-conductive adhesive. l...Liquid crystal display 4...Frame 7...Conductive filler 8...Binder 9...Conductive adhesive 12...Lower glass plate 15'...Printed circuit board Figure 1 1! Hayashi Densen,, l Jujidan 2nd figure 1:? Akira each thousand number 3rd figure times? Figure 4 (A) (B) Enlarged view of each HaoQ

Claims (1)

[Claims] An electronic device having a configuration in which a circuit member is connected to a printed circuit board constituting an electronic circuit using a conductive adhesive, characterized in that a pattern is provided at an end of the printed circuit board to prevent the conductive adhesive from protruding. and electronic equipment.