JPS6311665Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention is designed to inspect the operating state of electronic circuits from the back side of the circuit board, which has printed wiring on the front side of both the front and back sides, and is assembled in a frame. The present invention relates to the structure of a switch section for inspection.

2. Description of the Related Art Usually, in an electronic device, for example, an electronic wristwatch, inspection work is performed to determine whether the electronic circuit operates normally after the assembly process is completed. For this reason, a test switch terminal is provided on the circuit board so that the electronic circuit can be tested while the module in which the circuit board, liquid crystal panel, etc. are integrated is assembled in the watch case. This type of circuit board has a structure in which printed wiring is provided on both the front and back sides. That is, the first
FIG. 1 shows the front surface (upper surface in the figure) of a circuit board 1. On the surface of the circuit board 1, a large number of display electrode terminals 2 are connected to terminal electrodes of a liquid crystal panel (not shown). formed and also LSI package 3
A printed wiring 4 is provided to electrically connect the display electrode terminal and the display electrode terminal. Further, FIG. 1 2 shows the back side (bottom side in FIG. 1 1) of the circuit board 1, and printed wiring 4 is provided between the through holes 5 on the back side, and the operation of the electronic circuit is shown on the back side. Inspection switch terminals 6a and 6b for inspecting the condition
is formed, and one switch terminal 6a is connected to a high potential of a binary logic level via the printed wiring 4.
A signal at the V _DD level is supplied, and the other switch terminal 6b is connected to the reset terminal of an electronic circuit in the LSI package 3, such as a counting circuit (not shown), via a printed wiring 4. .

Therefore, when inspecting the operating state of the counting circuit, remove the back cover from the watch case with the module assembled in the watch case, insert a conductive tool through the opening, and insert the conductive tool into the watch case. Switch terminals 6a and 6 formed on the back side of the circuit board
By simultaneously contacting the switch terminals 6a and 6b, both switch terminals 6a and 6b become electrically conductive, and a high potential level signal is input to the reset terminal of the counting circuit.
The contents of the counting circuit are forcibly cleared and tested.

In this manner, in a circuit board having a configuration in which printed wiring is provided on both the front and back surfaces, it is possible to form test switch terminals on the back surface of the board. However, in order to reduce the cost of the circuit board, in a structure in which printed wiring is applied only to the surface of the board, it is not possible to form test switch terminals on the back surface of the board.

This idea was developed based on the above-mentioned circumstances, and its purpose is to maintain the operational status of electronic circuits even when using a low-cost circuit board with printed wiring only on the front side of both the front and back sides. It is an object of the present invention to provide a structure of a switch part that allows inspection work to be carried out easily and reliably.

An embodiment of this invention is shown below in Figures 2 to 4.
This will be explained in detail based on the figures. FIG. 2 is an exploded perspective view of an electronic wristwatch module to which this invention is applied. Note that the same parts as in the conventional example are indicated by the same reference numerals, and the explanation thereof will be omitted. In the figure, reference numeral 11 denotes a circuit board on which printed wiring is provided only on the front side (upper side in the figure) of both the front and back sides. This circuit board 11 is a housing (frame body) 12
It is fixed to the back surface (lower surface in the figure) of the device via screws 13. A rectangular space 14 is formed in the center of the upper surface of the housing 12 and passes through the housing 12 in its thickness direction, and a liquid crystal panel 15 is fitted into this space 14 . Further, in the wall portion 16 of the housing 12 that forms one side in the width direction of the space portion 14, two rectangular parallelepiped notches 17a and 17b are formed with a predetermined distance apart. Each of these notches 17a and 17b is open on the lower surface side of the housing 12 and on the side of the space 14, respectively, and the other portions are formed so as to be surrounded by the wall portion of the housing 12.

In addition, when the circuit board 11 is assembled into the housing 12, test switch terminals 18a and 18b for testing the operating state of the electronic circuit are arranged on the surface of the circuit board 11 facing each of the notches 17a and 17b, respectively. has been done. Each of these switch terminals 18
a.18b is electrically connected to the LSI package 3 via the printed wiring 4. A high potential signal is applied to one switch terminal 18a,
Further, the other switch terminal 18b has an electronic circuit,
For example, it is connected to the reset terminal of a counting circuit. In addition, each notch 17a of the housing 12.
Through holes 19a and 19b are formed on the surface of the circuit board 11 opposite to the switch terminals 17b, respectively, so as to closely oppose the switch terminals 18a and 18b and penetrate through the circuit board 11 from the back side to the front side. Note that the diameter of each through hole 19a, 19b is formed to a predetermined size, for example, a size that allows insertion of an existing conductive tool. On the other hand, reference numerals 20a and 20b denote rectangular parallelepiped conductive rubbers that are press-fitted into the notches 17a and 17b, respectively, and these conductive rubbers 20a and 20b are connected to the switch terminals 18a of the circuit board 11 when the watch module is assembled. 18b and through hole 1
The notches 17a and 17b are made to be slightly larger than the notches 17a and 17b so as to be pressed against the opening at one end of each of the notches 9a and 19b.

Note that the liquid crystal panel 15 is provided with an external terminal (not shown) on the widthwise flange thereof, and this terminal is connected to the interconnector 21a.
Display electrode terminal 2 of circuit board 11 via 21b
electrically connected to. Further, reference numeral 22 denotes a holding member for the liquid crystal panel, which is fixed to the housing 12 via screws 23. Further, reference numeral 24 indicates a battery, and the battery insertion notch 2 of the circuit board 11
5. Further, the reference numeral 26 indicates the circuit board 1
This is a crystal resonator attached to 1.

Figure 3 shows the switch terminal 18a and the conductive rubber 20.
Fig. 3a shows the assembly structure of one switch section constituted by the through hole 19a and the like. That is, when the circuit board 11 is fixed to the housing 12 via the conductive rubber 20a, the conductive rubber 2
Under the elastic force of 0a, the switch terminal 18a and one end opening of the through hole 19a come to be pressed against the conductive rubber 20a. And conductive rubber 20
a becomes exposed from the other end opening (back side of the circuit board 11) of the through hole 19a. In addition, the switch terminal 18b, the conductive rubber 20b, and the through hole 19b
The assembly structure of the other system section is also assembled in the same manner as described above. Thus, a conductive tool A formed as shown in FIG.
are inserted into the through holes 19a and 19b, and the conductive rubber 20
When a.20b is pressed, switch terminal 18a.1
8b is conductive rubber 20a, 20b and conductive tool A
electrically conductive through. This allows the operating state of the electronic circuit (counting circuit) to be inspected.

In this way, even if a circuit board 11 with no printed wiring on the back side is used, the operating state of the electronic circuit can be inspected from the back side of the circuit board 11. Furthermore, since the conductive rubber 20a and 20b are configured to press the liquid crystal panel 15 in the horizontal direction (leftward direction in FIG. 3), the liquid crystal panel
It also has the function of holding 5. In addition, since the conductive tool A can be strongly pressed against the conductive rubber 20a and 20b, the tool A and the conductive rubber 20a
Connection status with a.20b or switch terminal 18
The conduction state of a.18b is ensured. Furthermore, since the tool A is inserted into the through holes 19a and 19b, the positioning of the tool A becomes easy and the inspection work can be carried out efficiently.

In the above embodiment, the through hole is formed in the circuit board, but it may be formed in the housing or the like as long as it penetrates from the back side to the front side of the circuit board. In addition, although the conductive rubber was configured to be pressed into contact with the switch terminal and the opening at one end of the through hole,
The conductive rubber may be fixed to a predetermined location on the circuit board by adhesive or other means. Further, a part of the conductive rubber may be inserted into the through hole so that the conductive rubber is exposed on the back side of the circuit board.

Furthermore, although the above embodiments are provided with two switch sections, the number is not particularly limited. Furthermore, the switch can have any function. For example, it may be a switch that inputs initial time data into a clock counting circuit to perform a predetermined test, or it may be an all-clear terminal that resets all circuits. Furthermore, it may be a switch for checking whether all the segments constituting the display device are lit.

Moreover, although the above-mentioned embodiment shows the case where it is applied to an electronic wristwatch, this invention can of course be applied to electronic equipment such as a small electronic computer.

As explained in detail above, this device inspects the operating state of electronic circuits even when a circuit board with printed wiring on only the front side of both the front and back sides is assembled in a frame. Not only can the inspection work be carried out easily and reliably.

[Brief explanation of the drawing]

1.2 shows a conventional circuit board, FIG. 1 is its front view, FIG. 1 is its back view, and FIGS. 2 to 4 show an embodiment of this invention. 2
The figures are exploded perspective views of the clock module, Figures 3 and 4.
The figure shows the assembled state of the watch module, and Figure 3 shows the switch terminal 18a and the through hole 19a.
2 is an enlarged sectional view of the main part in the Y direction in FIG. 2, and FIG. 4 is an enlarged sectional view of the main part in the X direction in FIG. 2, passing through the through holes 19a and 19b. 4...Printed wiring, 11...Circuit board, 18
a.18b...Switch terminal, 19a.19b...Through hole, 20a.20b...Conductive rubber.

Claims (1)

[Scope of utility model registration request] A switch terminal formed on the top surface of the circuit board, a conductive rubber provided on the top surface of the circuit board and electrically connected to the switch terminal, and a conductive rubber formed on the bottom surface of the circuit board. a through hole formed so as to be exposed; and a switch portion configured to perform switching by bringing a conductive member into contact with the conductive rubber through the through hole from the lower surface side of the circuit board. structure.