KR100699343B1 - Smart Inclination Sensor and its Fabrication Procedures - Google Patents

Abstract

A small-sized inclination sensor and a method for manufacturing the same are provided to measure a direction of an inclination by comparing a size of a voltage measured at an equilibrium state with a size of a voltage measured according to an inclination angle. In a smart inclination sensor, a constant voltage is applied to one end(120) of a first electrode and the other end(130) of the first electrode is grounded. The voltage applied through the first electrode is distributed based on a predetermined formula. That is, a resistance value between the one end and the other end of the first electrode is distributed into a resistance value from the one end of the first electrode to a center of mercury and a resistance value from the center of the mercury to the other end of the first electrode. An output voltage is detected through a second electrode(140) as a sensing electrode. It is preferable that the second electrode is formed in a shape of a solenoid coil. And, the mercury is formed on a center of a semicircular channel.

Description

Small Inclination Sensor and its Fabrication Method {Smart Inclination Sensor and its Fabrication Procedures}

1A and 1B are schematic views of a tilt angle measuring sensor according to the prior art.

2 is a structural diagram of an inclination angle sensor according to an exemplary embodiment of the present invention.

3 is a manufacturing process diagram of a small tilt angle sensor according to an embodiment of the present invention.

4B and 4B are diagrams illustrating the operation of the structure of the inclination angle sensor according to the exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: glass plate

20: channel

40: ventilation hole

50: Silicon Wafer

80: pattern

The present invention relates to a sensor for measuring an inclination angle, and more particularly, by using a MEMS technique, a semicircular channel is formed on a glass plate and attached to a substrate having a resistor of a predetermined size, and then a certain amount of mercury or electrolyte in the channel. The present invention relates to a small inclination angle sensor capable of simultaneously measuring an inclination angle and a direction by measuring a voltage drop according to a change in resistance generated when mercury or electrolyte moves through a channel when the sensor is inclined.

As a sensor of inclination angle measurement according to the prior art, there is a method in which a rotation angle is detected as a change in resistance corresponding to the rotation angle by using a potentiometer principle to measure a steering angle, and then converted into an angle again. Has the disadvantage of being difficult to miniaturize.

In order to improve this, as shown in FIG. 1, an inclination angle sensor using a MEMS structure has been proposed, but the inclination angle sensor of FIG. 1 aligns an X-ray mask with poly methyl methacrylate (PMMA) and installs it in an emission accelerator to produce a channel. The Lithographie Galvanoformung Abformung) process is not only difficult to generalize the processing method, but also expensive to manufacture, making it difficult to commercialize.

In addition, the invention of the above technique is difficult to commercialize due to the slight change of the resistance value of the channel due to the change in position of mercury in the channel, making it difficult to commercialize, and to measure the voltage value according to the position of mercury in the channel. Only the tilt angle can be measured. That is, the above technique has a disadvantage in that it is not possible to obtain information on which direction the object is inclined as the mercury can only measure the inclination of the object equipped with the concentrically arranged resistor.

The present invention has been devised to solve the above problems, the first provides a small inclination angle sensor capable of measuring the inclination angle with a simple structure, the second provides an inclination angle sensor capable of measuring the inclination direction, and third manufacture of such an inclination angle sensor To provide a process.

In order to achieve the above object, the inclination angle sensor of the present invention forms a semicircular channel on a glass plate through MEMS processing, attaches it to a substrate on which a resistor of a predetermined size is designed, and then injects a certain amount of mercury or electrolyte into the channel. In this case, the voltage drop according to the change in resistance generated as the mercury or the electrolyte moves through the channel when the sensor is tilted can be measured.

In addition, the inclination angle sensor of the present invention is characterized in that the inclined direction can be measured by comparing the magnitude of the voltage measured in the equilibrium state with the magnitude of the measured voltage according to the inclination angle.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a structural diagram of an inclination angle sensor according to an exemplary embodiment of the present invention, which shows a left side, a plane, and a right side, respectively.

Referring to FIG. 2, first, a semicircular channel 20 is processed to have a constant channel width by using a glass plate (sodalime glass) 10. In this embodiment, the glass plate 10 was processed by a sand blasting process. The cross section of the channel may be formed of various kinds of polygons, and preferably has a semicircular cross section.

Subsequently, circular holes 30 of phi 1 (diameter 1 mm) are processed to a constant depth at different positions of the semicircular channel upper end portions on the rear surface of the glass plate 10. The circular hole 30 forms vent holes 40 having a predetermined size in a portion overlapping the semicircular channel 20 on the front surface. The vent hole 40 allows air to flow freely, thereby minimizing the effect of air resistance on mercury's movement as it slopes inside the channel.

Here, the reason why the size and position of the vent holes 40 on the rear surface of the glass plate 10 are slightly different is for the insertion of mercury, and the large hole is for the smooth injection of mercury and the flow of air, and the small hole is the air. It is desirable to minimize the size of the hole considering only the flow.

3 is a manufacturing process diagram of a small tilt angle sensor according to an embodiment of the present invention.

Referring to FIG. 3, a silicon wafer processing process and an adhesion process with the glass plate 10 according to an embodiment of the present invention will be described.

First, a silicon wafer (or silicon substrate) 50 is prepared, and a mask is fabricated to form a resistance of a certain shape on the silicon wafer 50.

Next, an oxide film SiO ₂ is grown on the silicon substrate 50 or a nitride film Si ₃ N ₄ is deposited to form an insulating film 60 to electrically insulate the silicon substrate 50.

Subsequently, in order to form an electrode shape, a gold / chromium layer (Au / Cr) 70 is deposited to a predetermined thickness (about 0.2 μm / 0.05 μm) on the entire surface of the silicon substrate 50. In this case, the chromium (Cr) layer is used as an adhesion layer for increasing adhesion between the insulating layer 60 and the gold (Au) electrode layer.

Then, after the photoresist is applied, the ultraviolet exposure (a) and the etching of the Au / Cr layer 70 are etched using an exposure and etching process generally used in a semiconductor process using a mask prepared in advance. When performed, the electrode pattern 80 is formed. The electrode pattern 80 may include a first electrode 120 linearly formed along one side of the channel 20 of the glass plate 10 and a solenoid coil type along the other side of the channel 20. It consists of two electrodes 140. In addition, a lower portion of the coil of the second electrode 140, that is, a portion contacting with mercury, has a polygonal (eg, rectangular) contact portion having an area larger than the diameter of the coil.

Subsequently, the silicon substrate on which the process is completed is cut into chips 90 having a predetermined size, and then an alignment pattern (eg, the glass plate 10 and the silicon chips 90 having the mercury moving channel 20 formed thereon) is formed on the silicon substrate. Adhesion according to 100). In this case, the silicon chip 50 and the glass plate 10 are bonded by using anodizing or an epoxy having excellent adhesive strength.

As a final step, the preparation of the inclination angle sensor 110 is completed by injecting an electrolyte such as mercury into the ventilation hole 40 in the channel 110 of the manufactured inclination angle sensor.

4A and 4B are diagrams illustrating the operation of the structure of the inclination angle sensor according to the exemplary embodiment of the present invention.

A constant voltage V is applied to one end 120 of the first electrode of the inclination angle sensor, and the other end 130 of the second electrode is grounded. Then, the voltage applied through the first electrode 120 is distributed by the following equation.

That is, the resistance value between the one end 120 and the other end 130 of the first electrode is the resistance value R ₁ from one end 120 of the first electrode to the center of mercury and the center of the first electrode at the center of mercury, respectively. It is divided by the resistance value R ₂ to the other end 130.

The output voltage V _output is measured through the second electrode 140 which is a sensing electrode. As shown in FIG. 4A, the second electrode 140 preferably has the form of a solenoid coil, and a lower portion of the coil, that is, a portion in contact with mercury, has a polygon (eg, a quadrangle) having an area larger than the diameter of the coil. The contact is formed. The polygonal contact portion can be designed by dividing it into a predetermined angle, thereby measuring the tilt angle more accurately.

When the tilt angle sensor is horizontal to the ground as shown in FIG. 4A, mercury is positioned at the center of the channel 20 formed in a semicircular shape. That is, mercury is positioned at the centers of both ends 120 and 130 of the first electrode. Therefore, since the applied voltage V is supplied with mercury, the voltage in the horizontal state is measured through the second electrode 140. At this time, since the inclination angle sensor is horizontal, 1/2 of the applied voltage (V) is measured through the second electrode 140 as the output voltage (V / 2) as the relationship of R ₁ = R ₂ is established.

On the other hand, when the inclination angle sensor according to the present invention is inclined as shown in Fig. 4b, the measured voltage is expressed as in the above formula, but the relationship of R ₁ > R ₂ is established between the resistance values R ₁ , R ₂ . Therefore, the voltage V _down measured through the second electrode 140 is measured to be smaller than the voltage V _neutral in the horizontal state.

On the contrary, when the inclination angle sensor is inclined in the opposite direction of FIG. 4B, the relationship R ₁ <R ₂ is established between the resistance values, so that the measured voltage V _up is measured larger than the voltage V _neutral in the horizontal state.

Therefore, the inclination angle sensor according to the embodiment of the present invention informs the state in which the object to which the inclination angle sensor is attached is inclined according to the magnitude of the measured voltage, for example, a situation in which the inclined surface is down or in an up state. Secures the feature.

According to the present invention, there is provided a compact inclination angle sensor that is manufactured in a compact and simple structure using MEMS technology and capable of precise inclination angle measurement.

According to the present invention, there is provided an inclination angle sensor capable of measuring the magnitude of the inclination angle as well as measuring the direction of the inclination by comparing the magnitude of the voltage measured in accordance with the inclination angle with the magnitude of the inclination angle.

According to the present invention, an effective process for manufacturing the compact tilt angle sensor is provided.

Claims (15)

Forming a semicircular channel on the front surface of the glass plate; Forming holes in the rear surface of the glass plate, the holes being connected to each end of the channel; And Forming a first electrode on the substrate, the first electrode having a shape matching with the one edge of the channel, and the second electrode having a shape matching with the other edge of the channel; And bonding the substrate to the front surface of the glass plate. The method of claim 1, And injecting an electrolyte into the channel through one of the holes. The method of claim 2, Forming a first electrode and a second electrode on the substrate, Forming an insulating film on the silicon substrate; Depositing a conductive metal layer on the insulating film; Exposing the silicon substrate using a mask having a shape pattern of the first electrode and the second electrode; And And etching the exposed silicon substrate. The method of claim 3, wherein The hole forming step, Forming a ventilation hole having a predetermined size connected to one end of the channel; And Forming a hole for the electrolyte injection of a predetermined size connected to the other end of the channel. The method of claim 4, wherein Wherein the channel forming step is inclined angle sensor manufacturing method characterized in that the step of forming the channel by sandblasting the glass plate. The method of claim 5, wherein And cutting the substrate on which the electrode is formed into a chip having a predetermined size after the electrode forming step. A glass plate having a semi-circular channel formed on a front surface thereof, and vent holes connected to respective ends of the channel formed on a rear surface thereof; A substrate coupled to the glass plate opposite the glass plate; A first electrode formed on the substrate and having the same shape as the channel; A second electrode formed on the substrate and formed to be spaced apart from the first electrode at predetermined intervals along the first electrode; And And an electrolyte provided in said channel. The method of claim 7, wherein The first electrode is a semi-circle as a linear electrode, the second electrode is a solenoid coil type electrode consisting of a plurality of windings, the inclination angle sensor, characterized in that the electrolyte contact portion is formed at the lower end of each winding of the second electrode. The method of claim 8, And a voltage applying terminal for applying a voltage at one end of the first electrode, and a ground terminal for grounding at the other end thereof. The method of claim 9, And said electrolyte is mercury. The method of claim 10, The substrate is a silicon substrate, and the surface of the silicon substrate is insulated with an oxide film or a nitride film, and the first electrode and the second electrode are deposited on the insulating oxide film or nitride film. The method of claim 11, The first electrode and the second electrode is inclined angle sensor, characterized in that composed of an Au / Cr layer. The method of claim 12, The voltage applied to the voltage applying terminal is called V _input , the resistance between the voltage applying terminal and the mercury is called R ₁ , the resistance between the mercury and the ground terminal is called R ₂ , and the second electrode When the voltage applied to is called V _output ,

Inclination angle sensor characterized in that the relationship between. The inclination angle sensor of any one of claims 7 to 13 is disposed on an inclined surface, and the angle and direction of the inclined surface are measured by changing the output voltage V _output according to the positional change of the mercury in the channel. Characterized inclination angle measurement method. The method of claim 14, And measuring the direction of the inclined plane by comparing the magnitude of the output voltage measured on the inclined plane with the output voltage measured in the equilibrium state.

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