JPS6222088A - Sensor part structure for magnetic detector - Google Patents

Abstract

PURPOSE:To reduce the occupation capacity of a sensor part, to facilitate the inspection of element sensitivity and to reduce variance in sensitivity by mounting a magnetoelectric converting element on a printed board and forming a wiring pattern for a coil on the board. CONSTITUTION:A sensor part 1 consists of the printed board 2 and magnetoelectric converting element 3 and the board 2 is made of an insulator; and the wiring pattern 4 is printed as a coil on one surface, a wiring pattern 5 for lead wires for the element 3 is printed on the other surface, and a through-hole 6 for top-reverse coupling is formed. Then, the element 3 is put in a magnetic field and driven by being fed with a current and a DC voltage obtained by amplifying and rectifying synchronously the output of the element 3 is fed back to the element 3 through a feedback coil 4. Consequently, the output of the element 3 becomes irrelevant to its Hall constant, and the thickness and driving current of the element.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a structure of a sensor section of a magnetic detector using a magnetoelectric conversion element (Hall element, magnetoresistive element, etc.).

(b) Conventional technology In general, magnetoelectric transducers have low sensitivity and have been used exclusively for measuring strong magnetic fields.
-Measurement of 3G order is also impossible (and measurement of weak magnetic fields has also attracted attention.In measurement of weak magnetic fields, in order to improve accuracy, it is necessary to flow a feedback current to the element or provide an inspection signal. In some cases, this type of magnetic detector uses a solenoid coil to provide a feedback signal, etc. In other words, the sensor section of the conventional magnetic detector is as shown in Fig. 6. A printed circuit board with a magnetoelectric conversion element a attached thereto was provided in a bobbin d of a solenoid coil C. Note that e is a lead wire for supplying current, and f is a lead wire for deriving voltage.

(c) Problems to be solved by the invention In recent years, the magnetoelectric transducer a has been miniaturized in the conventional magnetic detector described above, and even if an attempt is made to make the entire magnetic detector smaller by taking advantage of this advantage, the solenoid coil C is This hindered the ability to achieve the intended miniaturization. Further, in order to maintain a fixed positional relationship between the solenoid coil C and the printed circuit board, another holding member is required, which causes the problem of complicating the structure.

In view of the above, the present invention enables feedback signals and inspection signals to be supplied to the magnetoelectric transducer in a compact configuration, has a simple structure,
It is an object of the present invention to provide a sensor section of a magnetic detector that is easy to manufacture.

(d) Means and operation for solving the problems The sensor section of the magnetic detector of the present invention has a magnetoelectric transducer disposed in the center of a printed circuit board, and the magnetoelectric transducer is disposed on at least one surface of the printed circuit board. A spiral wiring pattern is formed around the conversion element.

In the sensor section of this magnetic detector, a spiral wiring pattern is used as a feedback coil or a check coil. Since the magnetoelectric conversion element and the spiral wiring pattern (coil) are attached to and formed on a printed circuit board, their mutual positions can be specified without providing any special members, and the space occupied is small.

(E) Examples The present invention will be explained in more detail with reference to Examples below.

FIG. 1 is a plan view of a sensor section of a magnetic detector according to an embodiment of the present invention, and FIG. 1 is a sectional view thereof.

A seven-sensor section 1 of this magnetic detector is composed of a printed circuit board 2 and a Hall element (magnetoelectric conversion element) 3.

The printed circuit board 2 is made of an insulator such as a glass substrate epoxy board or a phenol board, and has a rectangular spiral (or circular spiral) wiring pattern 4 printed on one side as a coil, and has a wiring pattern 4 printed on the other side as a coil. A wiring pattern 5 for a lead wire for the Hall element 3 and the like are printed thereon, and a through hole 6 is further provided to connect the front and back sides. .

The Hall element 3 is arranged at the center of the printed circuit board 2,
The lead terminal 7 is soldered to the wiring pattern 5 on the back surface via the through hole 6.

Note that 8 is an end for supplying drive current to the Hall element 3.
.

9 is a terminal for deriving the voltage of the Hall element, and 10 is a wiring pattern terminal of the coil.

A circuit example of a magnetic detector employing the sensor section 1 described above is shown in the fifth section.
Shown in the figure. Now, the Hall element 3 is placed in a magnetic field with a magnetic flux density B, and a current i is passed from the oscillator 11 to the terminal 8.8 through the transformer 12 to drive the Hall element 3. and,
From the terminal 9.9, an output is obtained as follows: VM = RM ・i − B/d where R i : Hall constant, d : thickness of the element. Here, there are manufacturing variations in R, d, and sensitivity correction is required. Therefore, the output of the Hall element 3 is amplified by the AC amplifier 13, and the DC voltage obtained by the synchronous rectifier 14 is further amplified by the DC amplifier 15 to obtain an output e0. Give feedback. And AC amplifier 1
3. If the gain of the DC amplifier 15 is set sufficiently large, the output eo is: eo=(Beeβ/Rf) (RH/di) ・From G, eo=(Rf/β)・B However, Rf: In series with the coil The resistance connected, β: coil constant, and the output e0 is independent of RHs d % 1.

In the above example, the spiral wiring pattern 4 is used as a feedback coil.
It can also be used as the inspection coil 4' by inputting calibration signals from the outside to the terminals 10'' and 10' without connecting to the output of the amplifier 15.

Further, in the above embodiment, there is one spiral wiring pattern 4 wound around the Hall element 3, but as shown in FIG. 3, the spiral wiring patterns 34 and 35 are doubled. It is also possible to wind the coil and use one end as a feedback coil (see coil 4 in FIG. 5) and the other as a check coil (see coil 4 in FIG. 5).

In addition, in the embodiment shown in FIGS. 1 and 2, there is only one printed circuit board, but when the magnetic field is insufficient due to only the coil 4 formed by printed wiring on this one printed circuit board 2,
As shown in FIG. 4, printed circuit boards 42 and 52 having coil wiring patterns 44 and 45 formed thereon may be superimposed adjacent to the printed circuit board 2 on which the Honil element 3 is attached. Note that an insulating plate 45 is interposed between the printed circuit boards 42 and 52. With this insulating plate in between,
It is also possible to stack printed circuit boards in multiple layers.

Furthermore, in the above embodiment, the wiring pattern for the coil is printed on only one side of the printed circuit board, but the wiring pattern for the coil may be printed on both sides of the printed circuit board.

(f) Effects of the Invention According to the present invention, a magnetoelectric conversion element is mounted on a printed circuit board, and a wiring pattern for a coil is formed on the printed circuit board so as to wind the magnetoelectric conversion element. The volume occupied by the sensor section can be reduced, making it possible to realize a compact magnetic detector as a whole. In addition, since no special members other than the printed circuit board are required to specify the positional relationship between the coil and the magnetoelectric transducer, the structure is simple.
Assembly becomes easy.

Furthermore, if the coil is used for inspection, the element sensitivity can be easily inspected, and variations in sensitivity among magnetic detectors can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view of each sensor section of a magnetic detector showing another embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, and FIG. 3 is a spiral shaped FIG. 4 is a cross-sectional view of a sensor section showing another example of the wiring pattern, FIG. 5 is a circuit diagram of a magnetic detector to which the present invention is applied, and FIG. 6 is a diagram showing another example of the wiring pattern. FIG. 2 is a cross-sectional view showing the structure of a sensor section of a conventional magnetic detector. 2, 42, 52 Niblint board, 3: Hall element, 4, 4', 44, 54: Wiring pattern for coil. Patent applicant: Shimadzu Corporation Agent
Patent attorney Shigenobu Nakamura ``b2 Brute copy (Figure 6)

Claims (2)

[Claims] (1) A magnetoelectric transducer is disposed in the center of a printed circuit board, and a spiral wiring pattern is formed around at least one surface of the printed circuit board. The structure of the sensor part of the magnetic detector. (2) At least two spiral wiring patterns are formed, one of which is used as a feedback coil of the magnetoelectric transducer, and the other one is used as a check coil. Structure of the sensor part of the magnetic detector.