JPH01296524A - High-sensitivity semiconductor pressure sensor - Google Patents

Abstract

PURPOSE:To obtain a correct measurement value by detecting the pressure guided through a pressure guide port via the resistance change due to the deflection of a silicone diaphragm. CONSTITUTION:A silicone diaphragm 3 is fixed to the center bottom of a plastic case 1 via a glass member 2, lead terminals 4 are integrally molded with the case 1, their ends are electrically connected to a gauge resistor (not shown in the figure) buried on the surface of the diaphragm 3 via bonding wires 5. The tip section of a needle-shaped projection 7 inserted into a hole provided at the center of a thin plate-shaped diaphragm 6 made of plastic and held by an adhesive or the like is brought into contact with the surface center of the diaphragm 3. On the other hand, the outer edge section of the diaphragm 6 is fixed to the cross section of the case 1 and a pressure shielding plate 8, this shielding plate 8 is fixed to the outer edge section of a cover 9. A space section formed by the diaphragm 6 and the cover 9 forms a pressure chamber 11 to apply the pressure of the guided fluid to the diaphragm 6 with the uniform distribution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a high-sensitivity semiconductor pressure sensor used for detecting fluid pressure, and particularly to a high-sensitivity semiconductor pressure sensor for low pressure.

[Conventional technology]

Conventionally, a semiconductor pressure sensor having a silicon diaphragm or the like has been used to detect the pressure of a fluid.

FIG. 3 is a longitudinal sectional view of a high-sensitivity semiconductor pressure sensor for explaining an example of such a conventional pressure sensor.

As shown in FIG. 3, such a high-sensitivity semiconductor pressure sensor is fixed to the bottom of the case 1 through a glass member 2 so as not to block a hole formed in the center bottom of the case 1, and is implanted in the case 1-. A silicon diaphragm 3 is connected to the terminal 4 by a punch ink wire 5, a needle-like protrusion 7 contacts the center of the surface of the silicon diaphragm 3, and an adhesive is attached to the center of the needle-like protrusion 7. A thin plastic tire phragm 6 is fixed to the outer edge of the diaphragm 6 and fixed to the outer edge of the case 1, and one end of the diaphragm 6 is fixed to the outer edge of the tire flap 1\6 and the other end is fixed to the outer edge of the tire flap 1\6 to enable pressure to be supplied to the diaphragm 6. It has a pressure introduction port 10 at the diaphragm 6, and a cover 9 for forming a pressure chamber 11 between the diaphragm 6 and the diaphragm 6. The pressure sensor having such a configuration concentrates the minute pressure of the medium introduced from the pressure introduction port 10 on the needle-shaped protrusion 7 to deflect the silicon diaphragm 3, thereby changing the resistance of the diffusion cage embedded on the silicon diaphragm 3. It is detected externally as a change in current, etc.

[Problem to be solved by the invention]

In the case of the conventional high-sensitivity semiconductor pressure sensor described above, when the pressure medium to be measured flows in at high speed through the pressure introduction port in the early stage, the fluid does not yet fill the pressure chamber, so it directly pushes the plastic diaphragm. You'll be hitting it hard. For this reason, accurate measurement of ζj is not possible at the beginning of the measurement, and the needle-like protrusion, which is originally provided to effectively concentrate the minute pressure of the fluid, is displaced more than the set value, and in the worst case The drawback is that the silico diaphragm itself is damaged.

An object of the present invention is to provide a high-sensitivity semiconductor pressure sensor that realizes accurate micro-pressure measurement even in the initial stage of measurement, and that does not cause displacement of the needle-like protrusion to exceed a set value.

[Means for resolving division issues]

The high-sensitivity semiconductor pressure sensor of the present invention includes a silicon diaphragm fixed on a case, a needle-like protrusion that abuts the center of the silicon diaphragm surface, and a needle-like protrusion that is fixed to the center and whose outer edge is fixed to the case. a pressure shielding plate having a shielding portion formed in the center and a fluid passage hole formed around the shielding portion, and a pressure shielding plate fixed to an outer edge of the thin plate-like diaphragm, and supplying pressure to the thin plate-like diaphragm. a cover that is fixed to the outer edge of the pressure shield plate at one end and has a pressure introduction port at the other end, and detects the pressure introduced from the pressure introduction port by a resistance change due to deflection of the silicon diaphragm. It is configured as follows.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal sectional view of a high-sensitivity semiconductor pressure sensor illustrating an embodiment of the present invention.

As shown in FIG. 1, a silicon diaphragm 3 of this semiconductor pressure sensor is fixed to the center bottom of a plastic case 1 via a glass member 2, similar to the conventional example shown in FIG. The lead terminal 4 is integrally molded with the case 1, and its end portion is electrically connected to a gauge resistor (not shown) embedded in the surface of the silico diaphragm 3 via a body ink wire 5. Further, the tip of a needle-like protrusion 7 inserted into a hole provided in the center of a thin plastic diaphragm 6 and held by an adhesive or the like is in contact with the center of the surface of the silicon diaphragm 3. On the other hand, the outer edge of the thin plate-shaped diaphragm 6 is fixed to the cross section of the plus deck case 1 and the pressure shielding plate 8. This pressure shielding plate 8 is connected to a pressure introduction bow 1 forming a cover 9.
A thin plastic diaphragm 6 shields the extension of the inlet of 0, and the pressure of the medium ejected from the inlet is directly applied to the diaphragm 6.
This is to prevent the cover from getting caught, and is fixed to the outer edge of the cover 9. Thereby, the space formed by the diaphragm 6 and the cover 9 is a pressure chamber 1 for applying the pressure of the introduced fluid to the diaphragm 6 in an even distribution.
] can be formed.

FIG. 2 is a plan view of the pressure shield plate shown in FIG. 1.

As shown in FIG. 2, the shielding plate 8 consists of a substantially circular central shielding part 12 formed in the center, a fluid passage hole 13 formed around the central shielding part 12, and a fixing part 14 formed on the outer periphery. There is.

In the semiconductor pressure sensor configured as described above, the fluid to be measured flowing in from the introduction port 10 first collides with the central shielding part 12 of the pressure shielding plate 8, and then disperses and passes through the fluid passage part 13 to reach the thin plate-like diaphragm 6. . After that, when the pressure chamber 11 is completely filled with the fluid to be measured, an evenly distributed pressure is applied to the surface of the diaphragm 6.
Add. Thin plate-like tire flutter with pressure (-1 applied ＼6
causes a deflection commensurate with the pressure, and applies a concentrated load fX1 to the silicon diaphragm 3 via the needle-like protrusion 7. As a result, the silicon diaphragm 3 is deflected, and due to the Vieso resistance effect of silicon, a mismatch occurs in the resistance values configured in the wheels 1 to 1 bridge. Detected as output.

〔Effect of the invention〕

As explained below, the high-sensitivity semiconductor pressure sensor of the present invention has a structure in which the extended line of the pressure inlet is shielded, so that the pressure of the medium suddenly flowing in can be directly applied to the thin plate-like tire flano. It is possible to prevent damage to the silicon diaphragm due to needle-like protrusions, and also to distribute the fluid in all directions and apply an evenly distributed load to the thin plate-shaped diaphragm. This has the effect of allowing accurate measurement values to be obtained.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a high-sensitivity semiconductor pressure sensor for explaining one embodiment of the present invention, FIG. 2 is a plan view of the shielding plate shown in FIG. 1, and FIG. 3 is for explaining a conventional example. FIG. 1. Case, 2. Glass member, 3. Silico diaphragm, 4.Lead terminal, 5. Punch ink wire, 6.
・・Plastic diaphragm, 7.・Acicular projection, 8・
...Pressure shielding plate, 9..Cover, 10..Pressure introduction port, ]1. Pressure chamber, 12. Central shielding part, 13.Fluid passage hole, ]4..Fixed part.

Claims (1)

[Claims] a silicon diaphragm fixed on the case; a needle-like protrusion abutting the center of the silicon diaphragm surface; a thin plate-like diaphragm having the protrusion in the center and having an outer edge fixed to the case; a pressure shielding plate that forms a shielding part and a fluid passage hole around the shielding part, and is fixed to the outer edge of the thin plate-shaped diaphragm; and one end of the pressure shielding plate for supplying pressure to the thin plate-shaped diaphragm. A high-sensitivity semiconductor pressure sensor, comprising a cover fixed to an outer edge and having a pressure introduction port at the other end, and detecting pressure introduced from the pressure introduction port by resistance change due to deflection of the silicon diaphragm. .