JP2001066272A - Flow sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a flow sensor that has simple structure and can be manufactured easily. SOLUTION: A photosensitive glass plate 30 is used as a heat insulation plate, resistance metal foils 10 and 20 with a thin pattern 11 are formed on the upper and lower surfaces of the glass plate 30, and then the photosensitive glass plate 30 is etched according to an etching pattern formed according to a photo work in advance, thus providing a gas circulation hole 31 and at the same time cutting into each sensor pellet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an improvement in a flow sensor used for quantitative analysis of gas components.

[0002]

2. Description of the Related Art Conventionally, a flow sensor used for quantitative analysis of a gas component is configured as shown in FIGS. In other words, a temperature-sensitive resistance metal foil with a large temperature coefficient of resistance is placed before and after in the gas flow, and these temperature-sensitive resistance metal foils are connected in a bridge, and a quantitative analysis of the gas component in the flow from the resistance change of the metal foil I do.

[0003] As a configuration, resistance metal foils 10 and 20 are provided on both front and back surfaces of a spacer 90 having a gas flow hole 91 at the center.
Are arranged, and the resistance metal foils 10 and 20 are fixed by being sandwiched between the heat insulating plates 70 and 80. Heat insulating plates 70, 8
0 has similar gas flow holes 71 and 81. Narrow width patterns 11 and 21 are formed in series in the resistance metal foils 10 and 20, and portions of the narrow width patterns 11 and 21 are exposed in the gas flow holes 71, 81 and 91. Wires 16, 17; 26, 27 are connected to the pads at both ends of the resistance metal foils 10, 20, and lateral holes 72, 73;
83 is provided on the heat insulating plates 70 and 80.

As the resistance metal foils 10 and 20, a metal having a large temperature coefficient of resistance (eg, Ni) is used. For the heat insulating plates 70 and 80 and the spacer 90, for example, glass or ceramic is used.

[0005]

However, the conventional flow sensor for quantitative analysis of gas components has a problem that the structure is complicated, the production is not easy, and the cost is increased.
That is, in order to provide the gas flow holes 91, 71, 81 in the spacer 90 and the heat insulating plates 70, 80, etching is usually performed using dilute hydrofluoric acid. Therefore, since iron-based metals are particularly corroded by hydrofluoric acid, it is difficult to place and fix a metal foil with the pattern as described above using this metal, and then open the glass with hydrofluoric acid. It is.

On the other hand, it is necessary to form a metal film by, for example, vacuum deposition or sputtering after forming an opening in the glass, and to perform patterning, since the metal film must span the opening. Impossible. Therefore, in the related art, the assembly is performed by arranging the patterned resistance metal foils 10 and 20 on the spacer 90 and sandwiching them between the heat insulating plates 70 and 80, which is not easy.

Further, since the resistance metal foils 10 and 20 are sandwiched between spacers 90 made of glass or the like and the heat insulating plates 70 and 80, wires for electrically connecting the resistance metal foils 10 and 20 to the outside are provided. Side holes 72, 73, 82, and 83 must be provided in order to draw out 16, 17, 26, and 27 to the outside, which results in a complicated structure and an increase in cost.

In view of the above, it is an object of the present invention to provide a flow sensor which has a simple structure, is easy to manufacture, and can be manufactured at low cost.

[0009]

In order to achieve the above object, in a flow sensor according to the present invention, a photosensitive glass plate and a resistive metal foil formed on the glass plate so as to include a narrow pattern are provided. And a gas flow hole formed by etching the glass plate so that the narrow pattern of the resistance metal foil is exposed inside the gas flow hole described later.

When a photosensitive glass plate is exposed to ultraviolet light, its area is easily dissolved in an etchant. Therefore, if an etching pattern is formed by selectively irradiating the photosensitive glass plate with ultraviolet rays in advance,
After forming a resistance metal foil including a narrow pattern on the photosensitive glass plate, the gas flow hole is opened such that the narrow pattern of the resistance metal foil is exposed inside the gas flow hole. It can be easily done without adversely affecting the metal foil. That is, since the structure is simple, it can be manufactured by a process of providing an etching pattern on a photosensitive glass plate, a process of forming a metal film, and a process of etching the photosensitive glass plate, thereby shortening the manufacturing process and increasing the efficiency. It can be manufactured, and the manufacturing cost can be reduced.

[0011]

Next, embodiments of the present invention will be described in detail with reference to the drawings. In the flow sensor shown in FIG. 1 and FIG.
0 is formed on both front and back surfaces of a photosensitive glass plate 30 which is a heat insulating plate.
Fixed on top. The resistance metal foils 10; 20 have narrow width patterns 11; 2 formed in series near the center.
1 and pads 12, 13; 22, formed on both ends thereof,
23. Photosensitive glass plate 30 and ceramic substrate 4
0, gas flow holes 31; 41 are formed, and the narrow patterns 11; 21 of the resistance metal foils 10; 20 are exposed inside the holes 31; 41 (inside the holes 31; 41). ).

The resistance metal foils 10, 20 are made of a conductive metal having a large temperature coefficient of resistance, such as Ni. The narrow patterns 11 and 21 have a width of, for example, 20 μm, and are arranged about 30 at intervals of 20 μm. The gas flow hole 31 provided in the photosensitive glass plate 30 is, for example, 1 mm.
It can be a four-sided square. Photosensitive glass plate 30
For example, silicate glass in which metal ions are added together with a sensitizer and dissolved can be used. In this glass, a region exposed to ultraviolet light is crystallized by a subsequent heat treatment, and is easily dissolved in hydrofluoric acid. As a specific product, “HOYA PEG3” manufactured by HOYA Corporation can be used.

Such a flow sensor is manufactured as follows. First, the photosensitive glass plate 30 as described above is used.
First, an etching pattern of the gas flow holes 31 and the sensor pellet separation line is formed by previously performing ultraviolet irradiation through a mask and subsequent heat treatment.

Next, resistance metal foils (thin films) 10 and 20 are formed on both surfaces of the photosensitive glass plate 30 to a thickness of about 2 to 3 μm by vapor deposition, sputtering or plating.
The resistance metal foils 10 and 20 on both sides of the photosensitive glass plate 30
A pattern including the narrow patterns 11 and 21 is formed by photo-working with respect to.

Thereafter, the above-mentioned etching pattern provided on the photosensitive glass plate 30 is etched with thin hydrofluoric acid to open the gas flow holes 31 and simultaneously cut off each sensor pellet. The etching of the gas flow holes 31 is performed through the space between the narrow patterns 11 and 21. However, the etching pattern of the photosensitive glass plate 30 is easily dissolved in hydrofluoric acid. The foils 10 and 20 are not adversely affected, and the narrow patterns 11 and
The glass can be completely removed except for 21.

Thereafter, the photosensitive glass plate 30 separated as a sensor pellet is mounted and fixed on a ceramic substrate 40. At this time, the photosensitive glass plate 30 is attached to the wiring patterns 42 and 43 provided on the surface of the ceramic substrate 40.
Are bonded with a silver paste or the like so that the pads 22 and 23 of the resistance metal foil 20 on the lower surface of the substrate are connected and fixed, respectively. Thereafter, wires 16, 17, 26 and 27 are respectively applied to the pads 12 and 13 on the upper surface of the photosensitive glass plate 30 and the wiring patterns 42 and 43 on the upper surface of the ceramic substrate 40 using silver pastes 14, 15, 24 and 25, respectively. Connecting.

FIGS. 3 and 4 show another example. The flow sensor shown in FIGS. 3 and 4 has basically the same structure as the flow sensor shown in FIGS. 1 and 2, but in FIGS. 1 and 2, a wiring pattern 42 is formed on a ceramic substrate 40. 43, the lower resistance metal foil 20 and the wires 26, 27 are connected to each other. In FIGS. 3 and 4, through holes 32, 33 are formed in the photosensitive glass plate 30 by gas. The lower resistance metal foil 20 is electrically connected to the pads 28 and 29 provided on the upper surface of the photosensitive glass plate 30 by filling the silver pastes 24 and 25 with the circulation holes 31 by etching and filling them with silver paste. are doing. As a result, not only the upper resistance metal foil 10, but also the lower resistance metal foil 20, the wires 26 and 27 for connection to the outside can be formed on the upper surface of the photosensitive glass plate 30 serving as a sensor pellet, and the connection is established. We are trying to make it easier.

FIGS. 5 and 6 show still another example. This example is basically the same as the examples of FIGS. 1 and 2 except that one photosensitive glass plate 30 is used instead of one photosensitive glass plate 30.
The photosensitive glass plates 30 and 50 are used. And
Resistive metal foils 10 and 20 are formed on one surface of each of the two photosensitive glass plates 30 and 50, that is, on the upper surface of the photosensitive glass plate 30 and on the lower surface of the photosensitive glass plate 50.

Here, two photosensitive glass plates 30, 5
After forming the resistance metal foils 10 and 20 on one surface of each of the photosensitive glass plates 30 and 50, the surfaces of the photosensitive glass plates 30 and 50 where the resistance metal foils 10 and 20 are not formed are bonded to each other. The glass plates 30 and 50 are overlaid. Next, the photosensitive glass plates 30, 5
0, the gas flow holes 3
The holes 1 and 51 are opened and cut into each sensor pellet. Further, it is mounted on a ceramic substrate 40, and the wires 16,
17, 26 and 27 are connected.

FIGS. 7 and 8 show that the through holes shown in FIGS. 3 and 4 enable the wire connection to the lower resistance metal foil 20 to be made on the upper surface of the photosensitive glass plate 30, and FIGS.
Another example having a structure in which the resistance metal foils 10 and 20 are respectively formed on one surface of each of the two photosensitive glass plates 30 and 50 in FIG. 6 is shown.

That is, in FIGS. 7 and 8, as in FIGS. 5 and 6, after forming the resistance metal foils 10 and 20 on one surface of each of the two photosensitive glass plates 30 and 50, these are formed. Bonding is performed so that surfaces on which the resistance metal foils 10 and 20 are not formed are in contact with each other. Etching is performed on the photosensitive glass plates 30 and 50 thus stacked, and the gas flow holes 31 and 51 and the through holes 32 and 33;
Is provided and separated into each sensor pellet. Next, silver pastes 24 and 25 are filled in through holes 32 and 52;
Pad 2 having both ends provided on the surface of photosensitive glass plate 30
8 and 29, and mounted on a ceramic substrate 40, and wires 16, 17, 26 and 27 are connected.

In the examples of FIGS. 7 and 8, both the advantages of the flow sensors of FIGS. 3 and 4 and the advantages of the flow sensors of FIGS. 5 and 6 can be obtained.

FIGS. 9 and 10 show a case where a photosensitive glass plate 60 serving as a spacer is arranged between the upper resistance metal foil 10 and the lower resistance metal foil 20. The upper resistance metal foil 10 is formed on the lower surface of the photosensitive glass plate 30, and the lower resistance metal foil 20 is formed on the upper surface of the photosensitive glass plate 50. On the upper surface of the photosensitive glass plate 30 (the surface on which the resistance metal foil 10 is not formed), metal pads 28, 29, 3
6, 37 are formed. These pads 28, 29,
In the portions of 36 and 37, three photosensitive glass plates 30, 6
0, 50, so that the glass plates 30, 60,
50 through holes 32 to 35, 62 to 6
5, 52 to 55 are formed.

In FIGS. 9 and 10, after forming the resistance metal foils 10 and 20 on one surface of each of the two photosensitive glass plates 30 and 50, the photosensitive glass plates 30 and 50 are used to form the photosensitive glass plates. The three photosensitive glass plates 30, 50, and 60 are stacked and bonded so as to sandwich 60. At this time, the side of the photosensitive glass plate 30 on which the resistance metal foil 10 is formed and the side of the photosensitive glass plate 50 on which the resistance metal foil 20 is formed are in contact with the photosensitive glass plate 60 serving as a spacer.
Next, the three photosensitive glass plates 3 were etched.
Gas flow holes 31 and 6 penetrating through 0, 60 and 50
1, 51 and through holes 32-35, 62-65, 52
To 55 are formed at the same time, and cut into each sensor pellet.

Then, the three photosensitive glass plates 30, 5
0, 60, through holes 32, 62, 52; 3
3, 63, 53; 34, 64, 54; 35, 65, 55
Are filled with silver pastes 24, 25, 14, and 15 so that both ends of the upper resistance metal foil 10
In addition to connecting to the pads 36 and 37 provided on the surface of the photosensitive glass plate 30, both ends of the lower resistance metal foil 20 are connected to the pads 28 and 29 provided on the surface of the photosensitive glass plate 30, respectively. At this time, the resistance metal foil 10 is connected to the through holes 32, 6
2, 52; 33, 63, 53, the resistive metal foil 10 does not come into contact with the silver pastes 24, 25 in these through holes. It is not electrically connected to the pads 28, 29. Also, since the pattern of the resistance metal foil 20 is also formed so as to avoid the through holes 34, 64, 54; There is no. After that, it is mounted on the ceramic substrate 40, and the wires 16, 1
7, 26 and 27 are connected.

In the flow sensor having the structure shown in FIGS. 9 and 10, the narrow patterns 11 and 21 of the resistive metal foils 10 and 20 are located at locations deep in the gas flow holes 31, 51, 61 and 41. , Are protected from outside obstacles.

[0027]

As described above, according to the flow sensor of the present invention, a photosensitive glass plate is used as a heat insulating plate, and a resistance metal foil is formed on the photosensitive glass plate. The gas flow hole can be formed without adversely affecting the resistance metal foil, the structure is simple, the manufacturing process can be shortened, and the manufacturing cost can be reduced. Further, since a photosensitive glass plate is used, separation of sensor pellets is easy, and a large number of sensor pellets can be manufactured at the same time. Furthermore, mounting is easy.

[Brief description of the drawings]

FIG. 1 is a schematic plan view showing an embodiment of the present invention.

FIG. 2 is a side view showing only a central portion of the embodiment in section.

FIG. 3 is a schematic plan view showing a second embodiment.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a schematic plan view showing a third embodiment.

FIG. 6 is a side view showing a cross section of only a central portion of the third embodiment.

FIG. 7 is a schematic plan view showing a fourth embodiment.

8 is a sectional view taken along line BB of FIG. 7;

FIG. 9 is a schematic plan view showing a fifth embodiment.

10 is a sectional view taken along line CC of FIG. 9;

FIG. 11 is a schematic plan view of a conventional example.

FIG. 12 is a sectional view taken along the line DD in FIG. 11;

[Explanation of symbols]

 Reference Signs List 10 upper resistance metal foil 20 lower resistance metal foil 11, 21 narrow pattern 12, 13, 22, 23, 28, 29, 36, 37 pad 14, 15, 24, 25 silver paste 16, 17, 26, 27 wire 30 , 50, 60 Photosensitive glass plate 40 Ceramic substrate 31, 41, 51, 61, 71, 81, 91 Gas flow hole 42, 43 Wiring pattern 32 to 35, 52 to 55, 62 to 65 Through hole 70, 80 Heat Insulating plate 90 Spacer 72, 73, 82, 83 Side hole

Continuing from the front page (72) Eiichi Hasegawa Inventor F-1term (reference) 2G060 AA01 AB01 AB15 AE19 AF07 AG06 AG11 BB02 BB09 EB04 KA01

Claims (1)

[Claims] 1. A photosensitive glass plate, a resistance metal foil formed on the glass plate so as to include a narrow pattern, and the narrow pattern of the resistance metal foil is exposed inside the gas flow hole described later. A gas flow hole formed by etching the glass plate.