JPH01119099A - Electronic instrument - Google Patents

Abstract

PURPOSE:To uniformly apply an adhesive without the affection of the shape of a casing inner surface to uniformize the thickness of the layer of the adhesive dropped at plural locations by forming an adhesive base table having a upper surface thereof positioned slightly lower than a surface thereof, on which surface a circuit board is placed for bonding therewith, and having a periphery thereof surrounded by a groove, and pressing the circuit board from the upper side of the adhesive dropped onto and applied on the upper surface of the adhesive base table to bond the circuit board with the internal surface of the instrument casing. CONSTITUTION:A columnar bonding base table 2a2 has the upper surface 2a4 located slightly lower than the surface of a substrate housing part 2a and having the periphery srrounded by a groove 2a5 of a trapezoidal cross section. An aqueous adhesive 12 is applied by potting on the upper surface 2a4 of the bonding base table 2a2. The aqueous adhesive 12 applied on the upper surface 2a4 gets to have a thickness following a space between the upper surface 2a4 and a wiring board 6 surface on the upper surface of the bonding base table 2a2 by being pressed on the wiring substrate 6 surface when the wiring substrate 6 is housed in and bonded with the substrate housing part 2a. Thereupon, a residual fraction of the aqueous adhesive is forced out from the upper surface 2a4 into the groove 2a5. The aqueous adhesive 12 applied on the upper surface 2a4 of the bonding base table 2a2 is therefore given a uniform layer thickness on the upper surface 2a4 of the same area, thereby uniformizing bonding force.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electronic device, such as a thin electronic computer, in which a circuit board on which electronic components such as an IC chip are attached is adhesively fixed to the inner surface of a device case.

[Prior Art] Generally, a circuit board of a small electronic device such as a thin electronic computer is adhesively fixed to a predetermined position on the inner surface of the device case using an adhesive or a double-sided adhesive tape.

Conventionally, when using adhesives, methods have been adopted, such as printing the adhesive at predetermined positions on the inner surface of the device case, or applying adhesive at multiple predetermined locations on the inner surface of the device case. In any of these cases, after applying an adhesive to the inner surface of the device case, a circuit board on which electronic components such as an IC chip are attached is pressure-bonded to the inner surface of the device case to obtain adhesive fixation.

[Problems to be Solved by the Invention] However, in the case of the method of printing adhesive on the inner surface of the a-base case, it is difficult to print and form the adhesive when the inner surface of the case is concave, and adhesive waves may occur. There was a problem in that the sexual location was significantly restricted by the inner shape of the case.

In addition, in the case of the method of applying adhesive to the inner surface of the device case by botting, it is difficult to set the layer thickness of the adhesive dripped at multiple locations uniformly, which makes it difficult to equalize the adhesive force. However, this method has a problem in that the applied adhesive takes a long time to dry and is difficult to control.

This invention was made in view of the problems mentioned above.
The purpose is to provide an electronic device that allows adhesive to be applied regardless of the shape of the inner surface of the case, and that allows the thickness of the adhesive to be applied uniformly to multiple locations. be.

c.Means for Solving the Problems] In order to solve the above problems, the present invention provides a method for solving the problems described above.
Ii. Form adhesive pedestals having upper surfaces slightly lower than the bonding placement part of one circuit board and surrounded by grooves at a plurality of predetermined locations on the inner surface of the device case to be placed; The circuit board is adhered to the inner surface of the equipment case by applying adhesive dropwise onto the top surface of the adhesive base and pressing the circuit board from above.

[Function] According to this configuration, when the circuit board is pressed and bonded to the inner surface of the device case, the adhesive applied dropwise to the top surface of each adhesive pedestal is connected to the top surface of the adhesive pedestal and the bottom surface of the circuit board. The amount of material applied in excess of the space between them will protrude from the top surface of the adhesive base and escape into the surrounding groove.

Therefore, the layer thickness of the adhesive applied to the top surface of each adhesive pedestal is uniform and has the same thickness as the space between the top surface of the adhesive pedestal and the bottom surface of the circuit board. For this reason, the adhesive force of the adhesive on all adhesive base portions is made uniform.

[Embodiment] An embodiment in which the present invention is applied to an i-type computer will be described below with reference to FIGS. 1 to 3.

As shown in Figure 2, this thin electronic calculator Jal is the size of a card type (85.5 x 54 m), and its thickness is approximately 3 mm, which is slightly thicker than the card type. As shown in FIG. 1, an electronic component component 3 is adhered and housed in a case z, and a top sheet 4 and a bottom sheet 5 are bonded to the top side and the bottom side of the case 2, respectively.

The electronic component structure 3 includes a wiring board 6, a circuit board unit 7,
It consists of a liquid crystal display panel 8, a solar cell 9, etc. The wiring board 6 is made of a soft film such as polyester with a conductive material patterned on the lower surface, and the negative side (left side in the figure)
A notch 6a is formed in which a part of the circuit board unit 7 is arranged, and connection parts 6b and 6c for the liquid crystal display panel 8 and the solar cell 9 are formed on the upper side.

In this case, the connecting portion 6b of the liquid crystal display panel 8 is provided with a notch to provide flexibility, and the connecting portion 6c of the solar cell 9 protrudes from both sides of the solar cell 9. Also,
The wiring pattern formed on the lower surface of the soft film consists of a large number of split movable contacts 6d, connection electrodes 6f of the liquid crystal display panel 8, connection electrodes 6g of the solar cell 9, and the like.

In this case, the movable contacts 6d are arranged over almost the entire lower surface of the soft film, and the connection electrode 6g is provided at the connection portion 6c of the solar cell 9. Further, a hot melt type anisotropic conductive adhesive is printed on the connection electrodes 6e and 6f.

The circuit board unit 7 is the first circuit board unit. second film substrate 7a,
An IC pellet 10 and a capacitor 11 are respectively mounted on 7b, and both are connected by a conductive metal lead (not shown). The film substrates 7a and 7b are formed of polyester, polyimide, epoxy resin containing glass fiber, bismaleimide triazine, etc., the first film substrate 7a is attached to the lower surface of the wiring board 6, and the second film substrate 7b is attached to the lower surface of the wiring board 6. is arranged corresponding to the notch 6a. That is, the first film substrate 7a has a rectangular shape, and a square hole 7a1 is formed in the center thereof, and the ICC PETZ 10 is arranged in the square hole 7aI, and a metal lead made of copper foil is provided on the upper surface of the first film substrate 7a. 7C is provided. One end of this metal lead 7c protrudes into the central square hole 7a+,
The IC pellet 10 is bonded to this protruding portion and is molded with resin 15, with the other end extending toward the outer circumferential side of the film substrate 7a. In this case, the lead pitch of the metal leads 7C is narrower on the side connected to the IC pellet 10 and wider on the side protruding to the outer periphery, thereby preventing short circuits between adjacent metal leads 7C170.

Further, each lead portion extending toward the outer circumferential side is formed to be thicker than the inner portion. Note that among these metal leads 7C, two metal leads 7C17C are the second metal leads 7C17C.
The other metal lead 7C is connected to the connection electrode (not shown) of the above-mentioned wiring board 6 using an anisotropic conductive adhesive. Further, a capacitor 11 is provided on the lower surface of the second film substrate 7b, and each lead 11a, 11a is connected to two metal leads 7cl, 7c2 of the first film substrate 7a from the back side. Note that the capacitor 11 is intended to stabilize the power source of the solar cell 9.

The liquid crystal display panel 8 displays input information and its calculation results, and is connected to connection electrodes 6f arranged on the connection portion 6b of the wiring board 6 using an anisotropic conductive adhesive. Further, the solar cell 9 is a power source for the entire device, and is connected to each connection electrode 6g, 6g provided on the connection part 6c, 6C of the wiring board 6 by an anisotropic conductive adhesive.

On the other hand, the case 2 houses the above-mentioned electronic component structure 3, and is made of hard synthetic resin.
, a battery storage section 2d is formed.

The board storage part 2a is for storing the wiring board 6, and has a shallow flat surface, and a recessed part 2al is formed in the part corresponding to the movable contact 6d of the wiring board 6, and does not correspond to this. Adhesive pedestals 2a2 are formed at predetermined locations, and external air circulation y connects these adhesive pedestals 2a2 vertically and horizontally.
t2a3 is formed. Figure 4 shows the above adhesive pedestal 2.
a2 and the outside air circulation groove 2a3 in detail, the adhesive pedestal 2a2 has a cylindrical shape, and the board storage part 2
It has an upper surface 2an that is slightly lower than the a-plane and is surrounded by a groove 2as having a trapezoidal cross section. Apply a water-soluble adhesive (emulsion adhesive, such as TB-1 from Three Pond Co., Ltd.) to the upper surface 2aa of this adhesive pedestal 2a2.
548 etc.) 12 is applied by potting. As shown in FIG. 5, the water-soluble adhesive 12 applied to the upper surface 28s is pressed against the surface of the wiring board 6 when the wiring board 6 is bonded and stored in the board storage part 2a, and is applied to the upper surface of the adhesive pedestal 2a2. 2as, the layer thickness is determined according to the space between this upper surface 2a4 and the wiring board 6 surface, and the excess material is deposited on the upper surface 2a.
It protrudes from an and escapes into the groove 2a5. Therefore,
The water-soluble adhesive 12 applied to the upper surface 2as of each adhesive pedestal 2a2 has a uniform layer thickness on the upper surface 2a4 of the same area, and the adhesive strength is made uniform. When the water-soluble adhesive 12 is applied to the upper surface 2a4 of the adhesive pedestal 2a2, the initial adhesive force causes the wiring board 6 to be attached to the board storage part 2.
The outside air circulation groove 2 is adhered and held on the side A, and then dried and solidified to obtain a predetermined adhesive force by the outside air flowing in from the outside air circulation groove 2a3 that communicates with the outside when the equipment is assembled.
A3 is a groove slightly deeper than the upper surface 2ai of the adhesive pedestal 2a2, and communicates with the groove 2a5 of the adjacent adhesive pedestal 2a2. In addition, as shown in FIG.
6 is formed, and a fixed contact 2a7 made of carbon or the like is provided on the upper surface of this protruding portion 2ab, and a movable contact 6d contacts the contact/separation portion.

The unit storage section 2b is for storing the circuit board unit 7, and as shown in FIG. The wiring board 8 to which -
It is pressed and fixed along the inclined surface. This is because the film substrates 7a and 7b are rigid and do not bend much. Therefore, by gradually deforming the wiring board 6 on the inclined surface, springback that inevitably occurs with the normal bending method is prevented. In this case, a four part 2b+ is formed in the center of the unit storage part 2b, and an opening part 2b2 is formed in the left end side of the four part 2b+. The recess 2bl is an IC
It stores pellets 1O, and the above-mentioned adhesive 12 is provided on the bottom surface. The opening 2b2 is the second
The film board 7b and the capacitor 11 are housed in the case 2, and the top and bottom of the case 2 are open.

The panel storage section 2C is for storing the liquid crystal display panel 8, and is formed relatively deeply on the upper left side of the case 2.

The battery storage section 2d is for storing the solar cell 9, and is formed on the upper right side of the case 2.
The side is a sloped surface, and the connection part 6 is connected along this slope.
g and 6g are transformed and connected to the solar cell 9.

The above panel storage section 2C and battery storage section 2d also have the above (
Similar to the board storage section 2a, adhesive pedestals 2c+ and 2d+ are formed at a plurality of predetermined locations thereof, and outside air circulation grooves 2C2 and 2d2 are formed to connect these. This adhesive pedestal 2
cl, 2dl and the outside air circulation grooves 2c2, 2d2 have the same structure as the adhesive pedestal 2a2 and the outside air circulation grooves 2&3 of the battery storage section 2d. The liquid crystal display panel 8 and solar cell 9 housed in the panel storage section 2C and the battery storage section 2d are bonded in the same manner as the wiring board 6 by a water-soluble adhesive 12 applied by botting to the upper surfaces of their adhesive pedestals 2c+ and 2dl. It is glued.

Extremely shallow sheet storage areas 2e and 2f are formed at the periphery of the upper and lower surfaces of the case 2, and a water-soluble adhesive 12 is applied from the outside into the outside air circulation grooves 2a3.2c2.2d2 at the periphery of the upper surface. A plurality of outside air intake grooves 2e+ are formed to take in outside air for drying.

The upper sheet 4 to be adhered to the upper surface of the case l is formed of a transparent resin sheet such as polyester, and a printed layer 4a is provided on the lower surface of the upper sheet 4, and a transparent adhesive is attached to the lower surface of the printed layer 4a as shown in FIG. This is a printed version of Agent 4b. In this case, the printed layer 4a is not provided at a location corresponding to the liquid crystal display panel 8 and the solar cell 9, but is provided at other locations, and a key is displayed at a location corresponding to the movable contact 6d of the wiring board 6. Mark 4e is attached.

The lower sheet 5 adhered to the lower surface of the case 2 is a transparent resin sheet made of polyester or the like with decorative printing applied to the upper surface, and is attached to the sheet storage section 2f on the lower surface side of the case 2 using the water-soluble adhesive 12. It is glued.

The thin electronic computer constructed as described above is assembled on an automatic assembly line shown in FIG. In this case, the electronic component structure 3 is manufactured in advance on a separate line (not shown), and the case 2 is formed into a predetermined shape by injection molding.

First, the case 2 is placed upside down on the conveyor 20. Then, the case 2 is conveyed by the conveyor 20, and the lower sheet 5 is adhered to the sheet storage section 2f on the lower surface side (the upper surface side in the figure) by a vacuum pad 21. That is, the vacuum head 21 vacuum-sucks the lower sheet 5, the lower surface of which is coated with the adhesive 12, and pushes it into the sheet storage portion 2f from above the case 2 to bond it.

The case 2 to which the bottom sheet 5 is adhered in this way is turned upside down and transported to a carbon transfer process, and in this carbon transfer process, the carbon ink on the transfer film 22 is transferred to the substrate storage part 2a of the case 2 by a heating jig 23. The outside air circulation groove 2a3 is formed by transferring. That is, the transfer film 22 is made by printing carbon ink on the lower surface of a base sheet via a release agent, applying a hot-melt adhesive on the surface of this carbon ink, and winding these into a roll.
It passes from one end of the heating jig 23 under the heating jig 23 and is wound up on the opposite side. Further, the heating jig 23 is used to thermocompress the transfer film 22 to the board storage section 2a of the case 2, and has suppression sections on its lower surface corresponding to the respective recesses 2&1 arranged and formed in the board wiring storage section 2a. is formed. This pressing portion is smaller than the inner diameter of the recessed portion 2al and larger than the outer diameter of the protruding portions 2&6 formed therein. Therefore, in this carbon transfer process, when the transfer film 22 is heated and pressurized by the heating jig 23 to the substrate storage section 2a in the case 2, the pressed part, that is, the protrusion 2a6 on the case 2 side, and the heat The carbon ink only in the part located between the pressing part on the jig 23 side was adhered to the upper surface of the protruding part 2a6 on the case z side with the adhesive, and the other carbon ink was not peeled off from the base sheet and remained attached. It is rolled up in a state. As a result, the protrusion 2a in the concave part 2al in the board storage part 2a of the case 2
Carbon ink is adhered onto 6, thereby forming a fixed contact 2a7.

The case 2 in which the fixed contacts 2a7 are formed in this way is sent to the next adhesive application process, where the fixed contacts 2a7 are provided at predetermined positions in each of the board storage part 2a, the panel storage part 2C1, and the battery storage part 2d of the case 2. Adhesive pedestal 2a2.
A water-soluble adhesive 12 is potted onto the upper surfaces of 2c+ and 2d+. The water-soluble adhesive 12 is supplied dropwise from a plurality of nozzle-shaped dispensers 24a of the botting device 24. In this case, each dispenser 24a is arranged corresponding to the adhesive pedestal 2a2.2cl, 2d1, and the water-soluble adhesive 12 is placed on these dispensers 24.
The same amount is dropped at the same time from a.

The case 2 coated with the water-soluble adhesive 12 in this manner is sent to the next step, where the electronic component structure 3 manufactured on another line is assembled into the case 2 by the vacuum head 26. At this time, the wiring board 6 of the electronic component assembly 3 presses the water-soluble adhesive 12 on the top surface of the adhesive pedestal 2a2 of the board storage section 2a, and the liquid crystal display panel 8 presses the water-soluble adhesive 12 on the top surface of the adhesive pedestal 2a2 of the board storage section 2a.
Press the water-soluble adhesive 12 on the adhesive pedestal 2c+ on the top surface of C, and the solar cell 9 is attached to the adhesive melting pedestal 2d+ of the battery storage section 26.
The water-soluble adhesive 12 on the upper surface is pressed to join the surfaces of the board storage section 2a, panel storage section 2C1 and battery storage section 2d. As a result, each adhesive pedestal 2a2.2cl, 2
The water-soluble adhesive 12 applied to the upper surface of d+ has a uniform layer pressure as described above. The wiring board 6 is bonded to the board housing portion 2a, the liquid crystal display panel 8 is bonded to the panel housing portion 2C, and the solar cell 9 is bonded to the battery housing portion 2d with uniform adhesive force using each of the water-soluble adhesives 12 thus made. .

Thereafter, the case 2 is sent to the next step, and the top sheet 4 is adhered to the top surface of the case 2 by the vacuum head 27. That is, the water-soluble adhesive 12 is previously provided on the lower surface of the top sheet 4, and the upper surface side thereof is vacuum-adsorbed by the vacuum head 27, and the sheet storage section 2f provided on the upper surface side of the case 2 is vacuum-adsorbed by the vacuum head 27. It is pushed inside and glued. As a result, the thin electronic computer 1 shown in FIG. 1, which is located at the end of the conveyor 20, is manufactured. After that, the assembled thin computer 1 dries the water-soluble adhesive 12, but when air is supplied from the air supply groove 2 to the outside air circulation 2a3.2c2.2d2, the water-soluble adhesive 12 is dried in a short time. Dry until a predetermined adhesive strength is obtained.

In this way, in this embodiment, since the outside air circulation groove is provided to allow outside air to flow into the bonded portion, there is an effect that the adhesive can be dried in a short time.

In the above embodiment, key contacts are provided on the case, but the present invention can also be applied to a general keyboard in which an elastic member having key contacts is arranged on the upper surface of a wiring board. If this is done, there is no need to provide a key contact on the case.

[Effects of the Invention] As explained above, in the electronic device according to the present invention, a plurality of predetermined locations on the inner surface of the device case where the circuit boards are bonded are located at positions slightly lower than the bonding surface of one circuit board. Adhesive pedestals having upper surfaces and surrounded by grooves are formed, and the circuit board is bonded to the inner surface of the device case by pressing the circuit board from above the adhesive applied dropwise to the upper surface of these adhesive pedestals. This structure has the advantage that the layer thickness of the adhesive applied by potting to a plurality of predetermined locations is uniform, and thereby the adhesive force can be made uniform.

[Brief explanation of the drawing]

Each of the drawings shows an embodiment of the present invention, and FIG. 1 is an exploded perspective view of a thin-type slave computer to which the present invention is applied, FIG. 2 is an external perspective view of the same thin-type electronic computer, and FIG. Figure 2 is a cross-sectional view taken along the ■-■ line in Figure 2, Figure 4 is an enlarged cross-sectional view showing the adhesive application part of the case, Figure 5 is an enlarged cross-sectional view showing the adhesive after the wiring board base material, and Figure 6 is an enlarged cross-sectional view showing the adhesive applied after the wiring board base material. 1 is a diagram showing an automatic assembly line for a thin electronic computer according to the present invention. 1...Thin computer, 2...Case, 2a...Board storage section, 2a2...Adhesive pedestal, 2&4...Top surface , 2a5...
・Groove, 6...Wiring board, io...IC
Pellets, 12...Water-soluble adhesive. Patent Applicant, Casio Computer Co., Ltd. Agent Patent Attorney Machi 1) Tadashi Toshi Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] In an electronic device in which a circuit board on which an electronic component such as an IC chip is attached is adhesively fixed to the inner surface of the device case, the circuit board is attached to a plurality of predetermined locations on the inner surface of the device case on which the circuit board is bonded and mounted. Adhesive pedestals having upper surfaces located at a position slightly lower than the bonding mounting surface of the circuit board and surrounded by a groove are formed, and the adhesive applied dropwise to the upper surfaces of these adhesive pedestals is formed. An electronic device characterized in that the circuit board is pressed from above and adhered to the inner surface of the device case.