JP4571329B2 - Electronics - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electronic device in which an electronic circuit is accommodated in a case.
[0002]
[Prior art]
In an electronic device, a nameplate is used to display information such as the model number, and this is generally fixed by being attached to the outer surface of the case. However, with the structure in which the nameplate is attached to the outer surface of the case in this way, when used in an atmosphere immersed in chemicals or in a corrosive atmosphere, the nameplate itself and the printed part on it are not specially corroded. It must be made of a new material or have a special structure, which is expensive. In addition, when the outer surface of the case is uneven or the case material is not adhesive such as polypropylene resin or fluorine resin, it is difficult to attach the nameplate to the outer surface of the case.
Therefore, for example, as shown in Japanese Utility Model Laid-Open No. 2-13278, a configuration has been proposed in which a case is made of a transparent or translucent resin and a nameplate is inserted into the case. In this way, there is no risk of corrosion because the nameplate is not exposed to the outside, and there is no need to consider the adhesion to the case.
[0003]
[Problems to be solved by the invention]
However, in the device described in the above publication, since the nameplate must be accommodated in the case separately from the original circuit parts, the case must be enlarged by the nameplate. However, there was a problem that the number of parts was large.
[0004]
The present invention has been completed on the basis of the above circumstances, and has the same function as that obtained by pasting the nameplate on the case surface, without causing an increase in the size of the case. An object is to provide an electronic device capable of reducing the number of parts.
[0005]
[Means for Solving the Problems]
As a means for achieving the above object, the invention of claim 1 is characterized in that a case in which a circuit board and a shield plate along the circuit board are accommodated in a case, the case is a translucent member. The nameplate display portion visible through the case is printed on the shield plate, and the shield plate is formed by bending a conductive sheet having elasticity to surround the circuit board, One end thereof is soldered and fixed to the ground line of the circuit board, and the other end is free from the circuit board and is in contact with the inner surface of the case by an elastic force. machine.
[0007]
[Action and effect of the invention]
<Invention of Claim 1>
According to the configuration of the invention of claim 1, since the case is translucent , the internal nameplate display portion can be visually recognized through this case, as in the case where the nameplate is attached to the outer surface of the case. The model number can be easily confirmed. Moreover, since the nameplate display is located in the case, it is not necessary to consider corrosion. Furthermore, the nameplate display unit is configured to be printed on a shield plate that is originally provided to cover the circuit board in the case, so a nameplate that is a separate component from the shield plate is accommodated in the case. Unlike the configuration, the case does not need to be increased in size and the number of parts does not increase. One end portion of the shield plate is soldered to the circuit board, the other is bent to surround the freedom and to a circuit board. For this reason, the shield plate exerts a force that swells due to its elastic force and is in contact with the inner surface of the case. As a result, since the distance between the nameplate display portion and the inner surface of the case is minimized, the visibility of the nameplate display portion is naturally greatly increased.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is applied to a liquid leakage sensor will be described with reference to the drawings.
Reference numeral 10 denotes a case of a liquid leakage sensor, which includes a case body 11 having one box-shaped surface opened and a lid 12 covering the open surface. Both the case main body 11 and the lid portion 12 are made of, for example, a fluororesin, and are made of a transparent material that is slightly clouded, so that the inside can be seen through from the outside. A pair of engagement arms 13 for attaching a leak sensor to a mounting post (not shown) and a wire lead-out for liquid-tightly penetrating the wire 14 led out from the internal electronic circuit are provided on the side surface of the case body 11. A tube 15 is projected.
[0009]
As shown in FIG. 3, a circuit board 20 is accommodated in the case 10, and a shield plate 30 is positioned so as to surround the circuit board 20. The circuit board 20 has a rectangular shape. A large number of electronic components 21 are mounted on both the front and back surfaces of the circuit board 20 as shown in FIG. 3, and the core wire of the wire 14 is soldered to a predetermined land.
[0010]
On the other hand, the shield plate 30 is formed by attaching a copper foil to a polyester film, for example, and can be elastically deformed. The shield plate 30 is formed by punching into a required shape, and a conductive piece 31 extends at one end. The shield plate 30 has the conductive piece 31 connected to a land connected to the ground line of the circuit board 20 by soldering, and the remaining part is free from the circuit board 20. It is bent so as to surround the periphery, and has a rectangular tube shape. As shown in FIG. 2, the shield plate 30 has black ink printed on the entire surface of the copper foil surface, with the conductive piece 31 remaining at the tip, in silver letters at a predetermined position. A nameplate display 32 on which the lot number is printed is formed. Next to the nameplate display portion 32, two window portions 33 are formed so that the copper foil is punched into a small circle and black ink is not applied to the portion, and these are mounted on the circuit board 20. It corresponds to two LEDs 22.
[0011]
Next, the mounting procedure of the shield plate 30 will be described in more detail.
As described above, the shield plate 30 is formed by attaching a copper foil to a polyester film, and a pressure-sensitive adhesive is partially applied to the surface of the polyester film opposite to the copper foil. The shield plate 30 is supplied to the printing process and the punching process of the black ink and the nameplate display unit 32 in a state where the peelable mount is attached to the surface on the adhesive side. In the assembly process of the leak sensor, as shown in FIG. 6, the electric wire 14 drawn through the electric wire outlet tube 15 is connected to the circuit board 20 to be accommodated in the case 10, and the circuit board 20 is placed outside the case 10. The shield plate 30 is wound around the circuit board 20 in the positioned state.
[0012]
For this purpose, first, the conductive piece 31 of the shield plate 30 is soldered to the land of the ground line, and in this state, a part of the shield plate 30 is attached to the flat surface of the electronic component 21 with the adhesive on the back surface (see FIG. 5). ). Since the shield plate 30 can be temporarily attached to the circuit board 20 in this way, the subsequent folding operation can be easily performed. Therefore, the shield plate 30 is sequentially bent along a plurality of perforations 30A formed in advance in the punching step, so that the entire circuit board 20 is finally wrapped in a rectangular tube shape (see FIG. 6). . At this time, since the shield plate 30 is fixed to the circuit board 20 only by the above-described conductive piece portion 31 and the other portions are free, the original flat sheet is obtained by the elastic force of the shield plate 30 itself. Although it tries to return to the shape, it is pushed into the case main body 11 of the case 10 while being held down. And if the cover part 12 is mounted | worn and it fixes by ultrasonic welding, an assembly operation will be completed.
[0013]
In the assembled state, the shield plate 30 is about to be deformed in a direction in which it is expanded from the square tube-like state by the elastic force as described above, and is free from the circuit board 20. In the accommodated state, a part is in contact with the inner surface of the case 10. As a result, the nameplate display portion 32 portion of the shield plate 30 is naturally closest to the inner surface of the case 10, and the nameplate display portion 32 can be reliably viewed from the outside of the case 10 even when the transparency of the case 10 is low.
[0014]
Thus, according to this embodiment, since the case 10 is transparent, the nameplate display part 32 formed on the internal shield plate 30 through this can be reliably recognized. Of course, since the nameplate display part 32 is located in the case 10, it is not necessary to consider corrosion etc., and it can be freely installed in a place where chemicals or the like may adhere. Furthermore, since the nameplate display 32 is configured to be printed on the shield plate 30 that is originally provided to cover the circuit board 20 in the case 10, the nameplate is a separate component from the shield plate 30. Unlike the configuration in which the case is housed in the case, the case 10 does not need to be enlarged and the number of parts does not increase.
[0015]
Moreover, in particular, according to the configuration of the present embodiment, the conductive piece portion 31 provided at one end portion of the shield plate 30 is soldered to the circuit board 20 and the others are freed and bent so as to surround the circuit board 20. ing. For this reason, the shield plate 30 exerts a force that swells due to its elastic force, and at least part of the shield plate 30 is in contact with the inner surface of the case 10. As a result, the nameplate display 32 and the inner surface of the case 10 Since the distance is minimized, the visibility of the nameplate display 32 is naturally greatly increased.
<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
[0017]
(1) Although the example applied to the liquid leakage sensor has been described in the above embodiment, the present invention is of course not limited to this, and can be widely applied to general electronic devices in which a circuit board and a shield plate are accommodated in a case.
[0018]
(2) In the above embodiment, the case 10 is made of a fluororesin. However, the case 10 is not limited to this. For example, a polypropylene resin or the like may be used. In short, any resin can be used as long as it is a translucent resin. it can.
[Brief description of the drawings]
FIG. 1 is a perspective view from the outside showing an embodiment of the present invention. FIG. 2 is a plan view with a lid part removed. FIG. 3 is a cross-sectional view taken along line III-III in FIG. Sectional view along line IV-IV in Fig. 1 [Fig. 5] Perspective view showing the middle of the assembly process [Fig. 6] Perspective view showing the middle of the assembly process [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Case 11 ... Case main body 12 ... Cover part 14 ... Electric wire 20 ... Circuit board 21 ... Electronic component 30 ... Shield plate 31 ... Conduction piece part 32 ... Nameplate display part 33 ... Window part

Claims (1)

In the case where the circuit board and the shield plate along the circuit board are housed together in the case,
The case is formed of a translucent member, and a nameplate display portion visible through the case is printed on the shield plate ,
The shield plate is formed by bending a conductive sheet having elasticity so as to surround the circuit board,
One end thereof is soldered and fixed to the ground line of the circuit board, and the other end is free from the circuit board and is in contact with the inner surface of the case by an elastic force. machine.

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