JPS5844629A - Method of producing detector - 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] The present invention relates to a method for manufacturing a detector.

Generally, detectors such as high-frequency oscillation type and capacitance type proximity switches are used to detect the approach of an object without coming into contact with the object.

The detector proximity switch is constructed as shown in Fig. 1, and the case 1 includes a cylindrical case body made of metal or resin, a front cover 2 made of resin covering both ends, and a metal or resin front cover 2 made of metal or resin. The back cover 3 of the watch has a slit. Note that the case body and the front cover 2 or back cover 3 may be formed integrally. Inside the case 1, there is a detection unit 6, which is disposed close to the front cover 2, such as a detection coil 5 wound around a ferrite core 4, and attached to the front cover 2, which also serves as a coil case. Built-in components such as a processing circuit section 7 connected to the detection section 6 and arranged near the center of the case 1 are housed. The processing circuit section 7 is formed by connecting an IC 9 and an object to be adjusted 1o on a substrate 8, and the object to be adjusted 10 is, for example, a semi-fixed resistor or a trimmer capacitor.

An operation display LED (light emitting diode) 11 is connected to the processing circuit section 7, and an optical fiber 12 is connected to this LED, the tip of which passes through the back cover.
The operation of the proximity switch can be confirmed from the outside by blinking EDl 1. Furthermore, the processing circuit section 7
An external lead-out cable 16 is connected to the case 1, and this cable 13 passes through the back cover 5 and is led out of the case 1.

In addition, since the above cannot protect each built-in component from external forces such as vibrations and shocks, and moisture, etc., the case 1 is filled with resin 14 such as epoxy resin and hardened to protect each built-in component. are doing.

Incidentally, recent electronic devices require resin molding after mounting on the board in order to improve environmental resistance and reliability, but in the proximity switch that detects changes in actance as described above, the detection part 6 is molded in resin. Then Q changes drastically. Therefore, as shown in Figure 2, first, the detection section 6 is molded in resin and connected to the processing circuit section 7, and after functional adjustment (mounting of selected parts, laser trimming, etc.) to achieve the optimum circuit constant, It is a two-stage system in which it is housed in a case 1 and the processing circuit section 7 is resin molded.

Note that 15 in the figure is a sensitivity adjustment piece, which is moved in the direction of the arrow.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a detector that allows quick and reliable function adjustment.

Hereinafter, one embodiment of the BFI of the present invention will be described in detail with reference to the drawings. The method for manufacturing a detector according to the present invention is constructed as shown in FIGS. 6 and 4. FIG. 4 shows the main parts of FIG. 6. Also, the same reference numerals are used for parts common or corresponding to those in FIG. 1. That is, 1. The processing circuit section 7 in the detector, that is, the proximity switch of the present invention includes a substrate 8.
The IC 9 and the body to be adjusted 10 are connected to the top. The object to be adjusted 10 is a thick film or thin film component, a thick film printed body on a ceramic substrate, or a chip component such as a printed resistor. The processing circuit section 7 and the detection section 6 are molded with a resin that does not easily absorb laser light, such as clear resin 14 (however, the case 1 is omitted in the figure).
. In this case, only the object 10 to be adjusted may be molded with a resin that does not easily absorb laser light, such as by two-color molding. Incidentally, FIG. 5 shows the relationship between the laser beam and the light transmittance of the clear resin. io
oomμ penetrates most epoxy resins. In addition, Nd: YA is generally used as a laser for laser trimming.
A G laser is used, and this Nd:YAG laser has i,0
61E1L near-infrared wavelength.

Now, as mentioned above, clear resin 1 that is difficult to absorb laser light
4, the laser source 16 is placed at a position corresponding to the object to be adjusted 10. This laser source 16 is connected to the external extraction cable 13.
The comparison circuit 17 is connected to a comparison circuit 17 for comparing with a set value. Then, the laser source 16 is turned on while focusing the laser beam 1B from the laser source 16 so that it can irradiate the object to be adjusted 10, and applying a predetermined voltage, current, etc. from the external lead wire to the processing circuit section 7. When the value is -0, most of the energy of the laser beam 18 is irradiated onto the object to be adjusted 10, and when the object to be adjusted 10 is, for example, a thick-film printed material, trimming of the thick-film printed material is started. Due to this trimming, the adjustment value of the object to be adjusted 10, that is, the thick film printed material changes, so the laser source 16 is turned off when the optimum circuit constant is reached by the signal from the comparison circuit 17. That is, the distance l
and a set value in advance, compare it with the set value while applying the laser beam 18, and when the set value is exceeded, a signal is issued and the laser beam 18 is stopped, and the functional adjustment of the object to be adjusted 10 is completed. .

The method for manufacturing a detector of the present invention is configured as described above and shown in the drawings, and since the object to be adjusted 10 is adjusted by irradiating the laser beam 18, even if the detection part 6 is changed by the mold resin 14, , optimal constants can be obtained with one molding. Further, since the adjustment is performed at high speed using the laser beam 1B, and is performed after complete molding, highly accurate characteristics can be obtained. Furthermore, in the past, after the optimum conditions were achieved on the adjustment line of the production process, the parts were returned to the production line f to be mounted, but according to the present invention, the production line and the adjustment line are completely separated. be able to.

In addition, if the mold resin 14 is slightly damaged by the laser beam, the resin 1 is attached to the adjusted body 10 as shown in FIG.
A transparent cup-shaped barrier 19 is provided in advance to prevent the laser beam 1 from entering, and then a mold resin 14 is filled to prevent the laser beam 1 from entering.
8 to the object to be adjusted 10 for adjustment. In this case, if the focus of the laser beam 18 is set on the object to be adjusted 10, the resin 14 will not melt in the area where the image is not formed, that is, in the vicinity of the barrier 19.

In the figure, 20 is air.

As explained above, according to the present invention, optimum circuit constants and highly accurate characteristics can be obtained in one molding process, and the manufacturing line and adjustment line can be completely separated in the second production process. A method for manufacturing a detector of great industrial value can be provided.

[Brief explanation of the drawing]

Figure 1 is a sectional view 1 showing the detector (proximity switch).
FIG. 2 is a side view including a partial cross section showing a conventional method for manufacturing a detector, FIG. 3 is a sectional view showing a method for manufacturing a detector according to an embodiment of the present invention, and FIG. 4(a), (bl is a plan view and side view showing enlarged main parts of Fig. 3, Fig. 5 is a characteristic curve diagram showing the relationship between the laser beam and the light transmittance of the clear resin,
FIG. 6 is a sectional view showing a modification of the present invention. 1...Case, 2...Front cover, 6...Back cover, 4...
- Ferrite core, 5... detection coil, 6... detection section, 7... circuit processing section, 8... board, 9... I
C1, 10...Object to be adjusted, 11...LED, 12.
...Optical fiber, 16... External lead-out cable, 14.
... Resin, 15... Sensitivity adjustment piece, 16... Laser source, 17... Comparison circuit, 18... Laser light, 19.
··barrier. Patent Applicant Tateishi Electric Co., Ltd. Representative Patent Attorney Tatsuo Ito Tetsuya Ito Figure 1 Figure 2 View Figure 3 Figure 4 A Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1. A cylindrical case having both ends formed by a front cover and a back cover, a detection section disposed close to the front cover inside the case, and a detection section connected to the detection section. a processing circuit section which is arranged in the case and has an adjusted body made of a thick film or thin film component; an external lead cable connected to the processing circuit section and passing through the back cover; In the detector, the object to be adjusted is irradiated with a laser beam so that an optimum circuit constant is obtained when a predetermined voltage and current are applied to the processing circuit section. A method for manufacturing a detector, characterized in that the detector is trimmed to adjust its function. 2. The method of manufacturing a detector according to claim 1, wherein the object to be adjusted is covered in advance with a barrier to prevent the resin from penetrating into the object to be adjusted.