JP6548067B2 - Gyro sensor - Google Patents

Description

  The present invention relates to a gyro sensor.

  As the gyro sensor, a vibrating gyro sensor and an optical gyro sensor are known. The vibration type gyro sensor detects Coriolis force acting on the vibrator when acceleration or centrifugal force acts, and detects angular velocity. However, in a device that moves dynamically, such as a robot, acceleration and centrifugal force are large, and the effects of linear acceleration, angular acceleration, and centrifugal force can not be ignored, causing drift. In addition, since the Coriolis force is proportional to the mass, the sensitivity is reduced when the size is reduced.

As the optical gyro sensor, a ring-shaped resonator (resonator ring), the pump laser is incident high from (excitation light source) intensity light generates stimulated Bed Lil Ann scattering as a nonlinear optical effect, thereby What utilizes the interference effect of the produced | generated laser beam is disclosed (for example, patent document 1). In this optical gyro sensor, when laser light circulates in a ring-shaped resonator, the time required for the circulation changes in accordance with the rotational angular velocity of the optical gyro sensor itself (Sagnac effect). The laser light which has circulated clockwise and counterclockwise has a phase difference corresponding to the rotational angular velocity. The optical gyro sensor detects the phase difference by measuring the intensity of the combined light of the laser beams circulating clockwise and counterclockwise, and detects the rotational angular velocity from this phase difference. The optical gyro sensor is different from the vibration type gyro sensor which detects the Coriolis force, and has the advantage that the drift due to the acceleration or the centrifugal force as described above does not occur.

JP-A-6-188526

  However, in the case of the optical gyro sensor described in Patent Document 1, since the sensitivity is proportional to the area surrounded by the ring resonator, there is a problem that it is difficult to miniaturize.

  Then, an object of the present invention is to provide a gyro sensor which can be miniaturized.

  A gyro sensor according to the present invention comprises: a main body having a flow path formed therein; a medium filled in the flow path; and a pressure sensor provided in the flow path for detecting an inertial force of the medium It is characterized by having.

  According to the present invention, since the inertial force of the medium is measured, downsizing can be realized.

It is a schematic diagram which shows the whole structure of the gyro sensor which concerns on 1st Embodiment. FIG. 1 is a partial end view schematically showing a configuration of a gyro sensor according to a first embodiment. It is a perspective view showing composition of a primary detecting element concerning a 1st embodiment. It is a figure which shows the manufacturing method of the detection part which concerns on 1st Embodiment in steps, FIG. 4A is an end elevation which shows the stage which formed the piezoresistance layer typically, FIG. 4B is a top view. It is a figure which shows the manufacturing method of the detection part which concerns on 1st Embodiment in steps, FIG. 5A is an end elevation which shows the stage which formed the electrode layer typically, FIG. 5B is a top view. FIG. 6A is a view showing in stages the method of manufacturing the detection unit according to the first embodiment, FIG. 6A is an end view schematically showing the stage of forming the outer shape of a cantilever, and FIG. 6B is a plan view. It is a figure which shows the manufacturing method of the detection part which concerns on 1st Embodiment in steps, FIG. 7A is an end elevation which shows the stage which partially removed the electrode layer typically, FIG. 7B is a top view. FIG. 8A is a view showing in stages the method of manufacturing the detection unit according to the first embodiment, FIG. 8A is an end view schematically showing the stage of removing a part of the Si substrate, and FIG. 8B is a plan view. Is a diagram showing a manufacturing method of the detection unit according to the first embodiment in steps, Figure 9A is an end view showing the step of removing the portion of SiO ₂ layer schematically, FIG. 9B is a plan view. It is a block diagram showing composition of an experimental device. It is a graph which shows the result of having measured resistance change rate of the gyro sensor concerning a 1st embodiment. It is a schematic diagram which shows the whole structure of the gyro sensor which concerns on 2nd Embodiment. FIG. 13A is a perspective view of the upper layer, and FIG. 13B is a perspective view of the lower layer in the structure of the upper layer and the lower layer in the gyro sensor according to the second embodiment. It is a perspective view which shows the structure of the intermediate | middle layer in the gyro sensor which concerns on 2nd Embodiment. It is a schematic diagram which shows the flow path in the gyro sensor which concerns on 2nd Embodiment. It is a perspective view of a base material for intermediate layers used for manufacture of a gyro sensor concerning a 2nd embodiment. It is a figure explaining the base material used for manufacture of the gyro sensor which concerns on 2nd Embodiment, FIG. 17A is a perspective view of the base material for upper layers, FIG. 17B is a perspective view of the base material for lower layers. It is a schematic diagram which shows the state of the manufacture process of the gyro sensor which concerns on 2nd Embodiment. It is a schematic diagram which shows the state before the cutting | disconnection of the gyro sensor which concerns on 2nd Embodiment. It is a top view which shows the structure of the detection part which concerns on a modification.

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

First Embodiment
(overall structure)
The gyro sensor 10 shown in FIG. 1 is provided so as to close the flow passage 12 and an annular main body 14 in which the flow passage 12 is formed, a medium (not shown) filled in the flow passage 12. And a pressure sensor 16 for detecting the inertial force of the medium.

  The main body 14 is not particularly limited, and can be formed of metal or resin. Further, the main body 14 is preferably formed of a material or structure having high thermal insulation properties, for example, preferably formed of a vacuum thermal insulation structure. The material constituting the main body 14 preferably has a thermal expansion coefficient close to that of the medium.

  The medium is preferably high in density because the sensitivity is high. Also, as the medium has higher viscosity, the sensitivity can be improved. Further, the medium is preferable in that the heat capacity is large, because the thermal stability can be improved. The medium may be fluid or gel. The fluid can apply liquid and gas. As the liquid, for example, water, silicone oil, ionic liquid or the like can be used. As the gas, for example, carbon dioxide, xenon or the like can be used. As the gel, for example, collagen, agarose gel and the like can be used.

  As shown in FIG. 2, the pressure sensor 16 includes a substrate 20 in which the opening 17 is formed, and a detection unit 18 provided on the substrate 20 so as to close the opening 17. The detection unit 18 includes an Si layer 24, an insulating layer 25, an upper Si layer 26, a piezoresistive layer 27, and an electrode layer 28. The upper Si layer 26 and the piezoresistive layer 27 form a cantilever portion 22.

  In the detection unit 18, an opening 30 connected to the opening 17 of the substrate 20 is formed on one side of the cantilever 22. Further, in the detection unit 18, a gap 23 is formed at the outer edge of the cantilever 22. The gap 23 penetrates in the thickness direction of the cantilever portion 22 and connects one side and the other side of the cantilever portion 22.

  The electrode layer 28 is electrically connected to a power supply (not shown) for supplying a current to the piezoresistive layer 27 through the substrate 20 and a signal conversion unit (not shown) for detecting a change in resistance value of the piezoresistive layer 27. ing. Although not shown, the electrode layer 28 is preferably covered with an insulator. The insulator can be omitted when the medium has an insulating property.

  As shown in FIG. 3, the cantilever portion 22 has a flat-plate-shaped pressure receiving portion 32 and a pair of hinge portions 34 integrally formed on one side surface of the pressure receiving portion 32. It is fixed at 37. The pair of hinges 34 are electrically connected to the electrodes 33 and 35, respectively. The electrodes 33, 35 are electrically disconnected. The cantilever portion 22 is formed to be elastically deformable around the hinge portion 34 by a pressure difference generated between one side and the other side of the cantilever portion 22.

  The gap 23 formed between the outer edge of the cantilever portion 22 and the frame 37 is formed in a size (width) in which the medium does not easily flow. The width of the gap 23 is preferably about 100 times or less of the mean free path of the molecules of the medium. If the width of the gap 23 is larger than 100 times the mean free path of the molecules of the medium, the medium leaks in the gap 23 and the sensitivity is lowered.

(Production method)
Next, a method of manufacturing the pressure sensor 16 will be described. First, the upper Si layer 26 of the SOI substrate 29 having the SOI structure is doped with an impurity by a thermal diffusion method or the like to form a piezoresistive layer 27 in which a part of the upper Si layer 26 is an N type or P type semiconductor (FIG. 4).

  Next, a photoresist mask is selectively formed on the piezoresistive layer 27, and gold, for example, is deposited by evaporation to form an electrode layer. By removing the photoresist mask, a cross-shaped pattern 36 in which the insulating layer 25 is exposed in a strip shape from each side is formed (FIG. 5).

  Next, using a focused ion beam (FIB: Focused Ion Beam) at the center of the pattern 36 with the cross-shaped pattern 36 as a mark, a groove 38 reaching the insulating layer 25 is formed, and the electrode layer 28, the piezoresistive layer 27. The upper Si layer 26 and the insulating layer 25 are etched into a cantilever shape (FIG. 6).

  Next, a photoresist mask is selectively formed on the electrode layer 28, and the electrode layer 28 at a position corresponding to the cantilever portion 22 is etched. The electrodes 33 and 35 are formed by removing the photoresist mask (FIG. 7).

  Next, the Si layer 24 immediately below the cantilever portion 22 is removed by plasma etching to form a hole 42 (FIG. 8). Further, the insulating layer 25 immediately below the cantilever portion 22 is removed by etching using HF vapor to form an opening 30 (FIG. 9). Thereby, one side and the other side of the cantilever part 22 are connected through the gap 23, and the detection part 18 can be obtained. In the case of the present embodiment, the gap 23 is formed to be tapered from one side to the other side of the cantilever portion 22 by processing using the FIB.

(Operation and effect)
In the pressure sensor 16 configured as described above, the detection unit 18 is provided so as to close the flow path 12, and the gap 23 formed in the detection unit 18 has a size (width) in which the medium is difficult to circulate Is formed. Therefore, when the gyro sensor 10 rotates the main body 14 in the direction of the arrow shown in FIG. 1, the medium filled in the flow path 12 is pushed by the detection unit 18 formed in the flow path 12. Thus, the medium rotates integrally with the main body 14. That is, a force necessary to rotate the medium integrally with the main body 14, that is, an inertial force of the medium acts on the pressure sensor 16. At this time, assuming that the pressure generated in the pressure sensor 16 is P, the radius of the main body 14 is r, and the density of the medium is ρ, the angular acceleration α generated in the gyro sensor 10 is expressed by the following equation (1).
α = P / (2πr · r · r) (1)

  The cantilever portion 22 of the pressure sensor 16 is elastically deformed about the pair of hinge portions 34 by the acting pressure P. Then, in the cantilever portion 22, the electric resistance value changes in accordance with the amount of deformation. The gyro sensor 10 can measure the pressure P by measuring the rate of change in resistance of the cantilever portion 22, thereby measuring the angular acceleration α.

  Since the gyro sensor 10 is configured to measure the inertial force of the medium, downsizing and improvement in sensitivity can be realized. The medium can be further miniaturized because the sensitivity can be further improved by using a dense medium such as a liquid.

  Further, by using a medium having a large heat capacity, for example, a liquid, the gyro sensor 10 can suppress the influence of a rapid temperature change and can improve the thermal stability.

  In fact, a pressure sensor 16 having a cantilever portion 22 having a length of 22.5 μm, a width of 20 μm, and a thickness of 0.15 μm was manufactured and evaluated. The hinge portion 34 has a length of 2.5 μm and a width of 0.5 μm. The width of the gap 23 was about 20 nm. The pressure sensor 16 was installed in the main body 14 so as to close the flow path 12 with a radius of 9.5 cm (flow path diameter 5 mm). The flow path 12 of the main body 14 was filled with silicone oil (density ρ: 1000) as a medium.

  As shown in FIG. 10, a power supply 50 is connected to the detection unit 18 of the pressure sensor 16 via a function generator (not shown). The electric resistance value of the detection unit 18 was measured by an oscilloscope 54 after removing noise by the lock-in amplifier 52 and converting it into a voltage.

  The electrical resistance value was measured when rotation of about ± 5 ° was given to the main body 14 with the center of the main body 14 as an axis, and the rate of change in resistance was determined. The results are shown in FIG. In the figure, the ordinate represents the resistance change rate, the abscissa represents the time, and the solid line represents the resistance change rate of the gyro sensor 10 according to the present embodiment. The dotted line in this figure gives ± 5 ° of rotation around the center to a conventional gyro sensor (product name: CRH01-100, manufactured by Silicon Sensing Systems, Inc., product name) installed at a position 9.5 cm away from the center. Rate of resistance change. From the figure, it can be confirmed that the gyro sensor 10 according to the present embodiment can obtain an output equivalent to that of the conventional gyro sensor 10 for a given rotation.

Second Embodiment
(overall structure)
The gyro sensor 100 shown in FIG. 12 is different from the first embodiment in that the main body 103 in which the flow path 102 is formed is plate-shaped. Hereinafter, the configuration of the gyro sensor 100 according to the present embodiment will be described in detail. The description of the same configuration as that of the first embodiment is omitted.

  The gyro sensor 100 is provided so as to close the flow path 102 with a main body 103 in which the flow path 102 is formed, a medium (not shown) filled in the flow path 102, and an inertial force of the medium And a pressure sensor 112 for detecting

  The main body 103 includes an upper layer 106, a lower layer 108, and an intermediate layer 110 sandwiched between the upper layer 106 and the lower layer 108. As shown in FIGS. 13A and 13B, the upper layer 106 and the lower layer 108 have channel forming grooves 121 and 124 formed on the inner surface, respectively. The flow path forming grooves 121 and 124 have a shape in which an annular ring is divided into two in the axial direction. One end portion 121 a of the flow path forming groove 121 of the upper layer 106 is formed to be vertically overlapped with the one end portion 124 a of the flow path forming groove 124 of the lower layer 108 and the intermediate layer 110. Similarly, the other end 121 b of the flow path forming groove 121 of the upper layer 106 is formed to overlap vertically with the other end 124 b of the flow path forming groove 124 of the lower layer 108 sandwiching the intermediate layer 110.

  As shown in FIG. 14, the intermediate layer 110 has a penetrating portion 128 formed at a position corresponding to one end 121a, 124a and a pressure sensor 112 formed at a position corresponding to the other end 121b, 124b. . The penetrating portion 128 penetrates in the thickness direction. The pressure sensor 112 has a detection unit 18 formed in parallel to the surface direction of the intermediate layer 110.

  In the main body 103 formed by sequentially stacking the upper layer 106, the intermediate layer 110, and the lower layer 108 configured as described above, as shown in FIG. 15, a flow path including an upper flow path 102a and a lower flow path 102b. 102 are formed. The upper flow path 102 a is formed by a flow path forming groove 121 and an intermediate layer 110 which are formed in the upper layer 106 as shown in FIG. 13A. The lower flow path 102b is formed by a flow path forming groove 124 and an intermediate layer 110 which are formed in the lower layer 108 as shown in FIG. 13B. The upper flow path 102a and the lower flow path 102b are connected via the communication part 104 corresponding to the penetration part 128 in which one end 121a, 124a is formed in the intermediate layer 110, and the other end 121b, 124b is the intermediate layer 110 It is connected via the pressure sensor 112 formed in.

  As in the first embodiment, the flow path 102 is filled with a medium (not shown). The pressure sensor 112 detects the inertial force of the medium. As the medium filled in the flow channel 102, the same fluid or gel as in the first embodiment can be used.

(Production method)
Next, a method of manufacturing the gyro sensor 100 according to the present embodiment will be described. The gyro sensor 100 is obtained by laminating predetermined substrates to produce a laminated body provided with a plurality of gyro sensors, and dividing them individually. The substrates used in the production are the substrate for the intermediate layer, the substrate for the upper layer, and the substrate for the lower layer, and in each of the substrates, a plurality of flow paths are produced and a plurality of gyro sensors are collectively obtained. A plurality of components are provided to be obtained. Details will be described below.

  First, as shown in FIG. 16, predetermined plate-like members are prepared, and the penetrating portions 128 and the pressure sensors 112 are formed in the plurality of unit regions 127 defined, to obtain the intermediate layer base 126. In the illustrated example, the shape of the intermediate layer base 126 is circular, but is not limited thereto. It can form using the plate-shaped member of arbitrary shapes.

  The penetrating portion 128 can be formed at a predetermined position of the unit region 127 by etching or the like. The pressure sensor 112 can be formed by the same method as that of the first embodiment.

  A plurality of penetration parts 128 and pressure sensors 112 are provided in the intermediate layer base material 126 produced in this manner.

  On the other hand, a plate-like member having the same size and shape is prepared, and as shown in FIG. 17A, a plurality of channel forming grooves 121 are formed from the back surface side to obtain an upper layer substrate 120. The channel forming groove 121 is formed in a region corresponding to the unit region 127 defined in the intermediate layer substrate 126. The flow channel forming groove 121 has an annular shape such that one end 121 a reaches the penetrating portion 128 and the other end 121 b reaches the pressure sensor 112 when the upper layer base material 120 is laminated on the intermediate layer base material 126. To form. The channel forming groove 121 can be formed by etching or the like.

  Furthermore, a plate-like member having the same size and shape is prepared, and a plurality of channel forming grooves 124 are formed from the surface side by the same method as shown in FIG. 17B to obtain the base material 123 for the lower layer. The channel forming groove 124 is also formed in a region corresponding to the unit region 127 defined in the intermediate layer substrate 126. The flow channel forming groove 124 has an annular shape in which one end 124 a reaches the penetrating portion 128 and the other end 124 b reaches the pressure sensor 112 when the upper layer base material 120 and the lower layer base material 123 are stacked. Form.

  Next, as shown in FIG. 18, the lower layer substrate 123 is disposed below the intermediate layer substrate 126, and the upper layer substrate 120 is disposed on the intermediate layer substrate 126. Join the The upper layer substrate 120 is a layer for the intermediate layer so that one end 121a of the flow channel forming groove 121 overlaps the pressure sensor 112 with the penetrating portion 128 provided in the intermediate layer substrate 126 and the other end 121b. It is joined to the material 126. Similarly, the lower layer base material 123 is intermediate such that the one end portion 124 a of the flow channel forming groove 124 overlaps the pressure sensor 112 with the penetrating portion 128 provided in the intermediate layer base material 126 and the other end portion 124 b. It is joined to the base material 126.

  An upper flow passage 102 a is formed between the flow passage forming groove 121 provided in the upper layer base material 120 and the surface of the intermediate layer base material 126. A lower flow passage 102 b is formed between the flow passage forming groove 124 provided in the lower layer base material 123 and the back surface of the intermediate layer base material 126. The upper flow path 102a and the lower flow path 102b are connected at one end portions 121a and 124a by the communication portion 104, and the other end portions 121b and 124b are connected via the pressure sensor 112 to form the flow path 102. . The flow path 102 is filled with a medium.

  Thus, as shown in FIG. 19, a plurality of gyro sensors 132 are formed on the laminate 130 obtained by sandwiching and bonding the intermediate layer substrate 126 between the upper layer substrate 120 and the lower layer substrate 123. The Rukoto. These are individually cut using, for example, a dicing apparatus to obtain the gyro sensor 100 of the present embodiment.

(Action and effect)
As described above, the gyro sensor 100 according to this embodiment includes the pressure sensor 112 having the same configuration as that of the first embodiment, and can be filled with the same medium. Therefore, when movement is given to the gyro sensor 100 so that the flow path 102 rotates in the direction of the arrow shown in FIG. 15, the same action as that of the first embodiment is produced, and the same effect is obtained. .

  That is, as in the case of the first embodiment, the gyro sensor 100 is configured to measure the inertial force of the medium, so downsizing and improvement in sensitivity can be realized. In addition, by appropriately selecting the medium, it is possible to further miniaturize and to improve the thermal stability.

  Moreover, in the gyro sensor 100 according to the present embodiment, the flow path 102 includes the upper flow path 102a and the lower flow path 102b, and the upper flow path 102a and the lower flow path 102b are pressure sensors provided laterally. It is divided by 112. The middle layer 110 provided with the pressure sensor 112 constitutes a part of the upper flow passage 102 a and the lower flow passage 102 b. With such a structure, when manufacturing the gyro sensor 100, it is possible to laminate a predetermined base material and simultaneously perform the formation of the flow path 102 and the arrangement of the pressure sensor 112.

  Since a plurality of components are provided in the base material to be stacked so that a plurality of flow channels can be produced, the plurality of gyro sensors 100 can be manufactured collectively by stacking the base materials. By individually cutting the collectively manufactured gyro sensors 100, it has become possible to efficiently manufacture a plurality of gyro sensors 100 in a simplified method.

(Modification)
The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the present invention.

  For example, as shown in FIG. 20 in which the same reference numerals are given to the configuration corresponding to FIG. 3, the detection unit 60 may be provided with a temperature compensation element 62. The detection unit 60 has a cantilever 22, and a temperature compensation element 62 is formed between the pair of hinges 34 of the cantilever 22. The temperature compensating element 62 has the same characteristic as the resistance change characteristic with respect to the temperature which the cantilever portion 22 has. In the case of this modification, the temperature compensating element 62 may be a non-deformable cantilever portion, such as a temperature sensor, whose electrical resistance changes with temperature change. In the case of this modification, the temperature compensating element 62 has an outer shape similar to that of the cantilever portion 22 but the piezoresistive layer 27 is not formed. A second gap 64 is formed between the temperature compensating element 62 and the cantilever portion 22. The second gap 64 preferably has the same width as the gap 23. Further, the temperature compensating element 62 is bifurcated on the base end side, and a pair of legs 63 and 65 are formed. An opening 66 is formed between the legs 63 and 65, and the pair of legs 63 and 65 are connected to the electrodes 67 and 68, respectively. The electrodes 67 and 68 are electrically disconnected from each other and the electrodes 33 and 35 connected to the cantilever portion 22.

  The temperature compensation element 62 configured as described above outputs a signal according to the temperature of the detection unit 60. The gyro sensors 10 and 100 can perform temperature compensation on the electrical resistance value of the cantilever portion 22 by using the signal output from the temperature compensation element 62. Specifically, the gyro sensor 10, 100 measures the electrical resistance value accompanying the rotation of the main body 14, 103 by the cantilever portion 22 and measures the actual temperature by the temperature compensation element 62. A compensation value corresponding to the actual temperature is calculated from the temperature characteristic of the cantilever portion 22 measured in advance. Thus, the gyro sensor 10, 100 can perform temperature compensation on the electrical resistance value by dividing the compensation value from the measured electrical resistance value.

  Further, by arranging the three gyro sensors 10 and 100 in three directions in which the main bodies 14 and 103 are orthogonal to each other, acceleration in the three axial directions can be measured.

  Furthermore, in the intermediate layer 110 shown in FIG. 14, the pressure sensor 112 may be formed instead of the penetrating portion 128. In that case, the pressure sensor 112 is provided at a position corresponding to the one end 121 a of the upper layer 106 and the one end 124 a of the lower layer 108 and a position corresponding to the other end 121 b of the upper layer 106 and 124 b of the lower layer 108. The gyro sensor 100 measures the pressure P by measuring the rate of change in resistance of the cantilever portion 22 in the two pressure sensors 112, whereby the angular acceleration α can be measured with high sensitivity, and temperature compensation for the electrical resistance value You can also do

Reference Signs List 10, 100 gyro sensor 12, 102 flow path 14, 103 main body 16, 112 pressure sensor 22 cantilever portion 23 gap 37 frame body 104 communicating portion 106 upper layer 108 lower layer 110 intermediate layer 62 temperature compensating element

Claims (7)

A body which is an annular ring in a plan view, is formed in a tubular shape, and has a flow passage formed therein;
A medium filled in the flow path,
A pressure sensor provided in the flow path for detecting an inertial force of the medium;
The pressure sensor is to have a resiliently deformable cantilever portion formed so as to partition the flow path,
The gyro sensor according to claim 1, wherein the cantilever portion is elastically deformable in a circumferential direction of the annular ring . The gyro sensor according to claim 1, wherein the cantilever portion has a piezoresistive layer. A frame provided around the cantilever portion and holding a proximal end of the cantilever portion, and a gap formed between the cantilever portion is 100 times or less of the mean free path of the medium. The gyro sensor according to claim 1. The gyro sensor according to any one of claims 1 to 3, wherein the medium is a liquid. The gyro sensor according to any one of claims 1 to 4, further comprising a temperature compensation element for compensating the temperature characteristic of the cantilever portion. 6. The gyro sensor according to claim 5, wherein the temperature compensation element is a non-deformable cantilever portion having the same characteristic as a resistance change characteristic with respect to a temperature of the cantilever portion. A main body in which a flow passage is formed, and
A medium filled in the flow path,
A pressure sensor provided in the flow path for detecting an inertial force of the medium;
The pressure sensor includes an elastically deformable cantilever portion formed to partition the flow path,
A frame provided around the cantilever portion and holding the proximal end of the cantilever portion, and a gap formed between the cantilever portion is not more than 100 times the mean free path of the medium
A gyro sensor characterized by

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