JPH06347473A - Posture sensor - Google Patents

Abstract

PURPOSE:To detect change in posture in many directions by making up each posture sensor of a first beam section formed in a structure liable to be strained so as to be deformed in a specified direction, and of a plurality of beams liable to be strained so as to be deformed in the direction different from that of the first beam, and making comparison strain signals from these detecting sections are made to pass through each low-pass filter. CONSTITUTION:The quantity of displacement of each beam 102 and 104 is changed by that static force due to gravity is applied to the first and second beams 102 and 104 to change sensors in direction. When the beam section 102 is subjected to gravity in the direction 109, it is strained the most, and when the beam section 104 is subjected to gravity in the direction 110, it is strained the most. The quantity of strain in the beam section 102 is determined by its detecting sections 108 at both the sides of a neutral surface of strain, and the quantity of strain in the beam section 104 is determined by detecting change in capacitance between an electrode provided for a surface opposite to a second overlapping section 103 and the overlapping section 103. The voltage signal of the detecting section 108 and the capacitance signal of the beam section 104 are changed into voltage by a capacity-voltage conversion circuit 302, and the high frequency portion is cut-off by low-pass filters 303 and 305. Comparison is made by a comparison circuits 303 and 304 with voltage values set in advance, and judgement is made on the directions 109 and 110, so that a posture is thereby judged by a comparison circuit 307.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small posture sensor which can easily detect the posture of an object.

[0002]

2. Description of the Related Art As a method of detecting the posture of an object, there is known a means for detecting the posture from the relative change by using a plurality of sensors such as an acceleration sensor, a velocity sensor and a displacement sensor for detecting the relative change of the object. . In addition, a posture sensor that detects a posture change of an object using gravity is also known.
FIG. 12 is a posture sensor that detects a change in the posture of an object based on two values. Mercury 122 is enclosed in the glass container 121, and this mercury moves along with the change in the attitude of the object, and when both of the metal probes 123 and 124 are touched, the resistance between the metal probes 123 and 124 decreases. , It is possible to detect changes in the posture of an object. By using a plurality of attitude sensors, it is possible to detect attitude changes of an object in multiple directions.

[0003]

It is desirable that the attitude sensor mounted on a small device is small in size. However, the conventional attitude sensor is large in size, and when detecting attitude changes in a plurality of directions, a large number of sensors must be separately incorporated. Further, when mercury is used, there is a problem that its application is limited in terms of safety and environment.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a posture sensor which can detect posture changes in multiple directions with a simple structure without using mercury. .

[0005]

The present invention is intended to solve the above-mentioned problems, and it is connected to a first beam portion and a first beam portion which are structured so as to be easily strain-deformed in a specific direction. , First
Each of the beam parts is formed of at least one beam part having a structure that is easily deformed in a direction different from the deformation direction of the beam part, and each beam part is integrally formed by etching the base. The distortion signal from the detection unit that detects the amount of distortion is transmitted through the low-pass filter, and then the orientation of the object is detected by comparing the signal values of each. To provide the attitude sensor of

Further, according to the present invention, by processing the substrate using the photolinography method and the etching technique, the size of the sensor can be reduced and the posture change in multiple directions can be detected in accordance with the improvement of the processing accuracy which is difficult in the conventional machining. , And high mass productivity at the same time.

As a processing material to which the photolinography method and the etching technique can be applied, a material having a high etching processing accuracy such as a photosensitive glass or a crystal can be used in addition to a silicon single crystal.

Another feature of the present invention is as follows.
The strain direction of the first detection beam lies in the etching in-plane direction of the substrate. Etching proceeds from the surface in the depth direction. Therefore, the structure that is easily deformed in the direction parallel to the etching surface has lower manufacturing accuracy than the method of forming the structure perpendicular to the etching surface. In the configuration of the present invention, the second beam portion and the weight portion coupled to the second beam portion act as the weight of the first beam portion. Therefore, by setting the beam having low fabrication accuracy as the first beam, it is possible to easily obtain the same sensor characteristics in the two sensing directions.
At this time, the sensor size can be significantly reduced as compared with the case where each sensor is formed separately and the case where the detection directions of the first beam portion and the second beam portion are opposite.

[0009]

EXAMPLES The present invention will be described in more detail based on the examples shown in the drawings, but the present invention is not limited thereto.

(Embodiment 1) FIGS. 1 to 5 show a first embodiment of the attitude sensor of the present invention. FIG. 1 is a structural diagram of the attitude sensor of this embodiment, and FIG. FIG. 3 is a drawing for explaining the signal processing method of the orientation sensor of this embodiment, and FIGS. 4 and 5 are application examples of the orientation sensor of this embodiment for a camera orientation sensor. FIG.

In FIGS. 1 and 2, 101 is a first weight portion, 102 is a first beam portion for detection, 103 is a second weight portion, 104 is a second beam portion for detection, and 105 is a beam portion. A silicon single crystal substrate, 106 is a frame portion, 107 is a void portion formed by etching removal, 108 is a detection portion, 109 is the strain direction of the first beam, and 110 is the strain direction of the second beam.

In the present embodiment, a static force is applied to the first beam portion 102 and the second beam portion 104 due to gravity, and the displacement amount of each beam is changed by changing the direction of the sensor. At this time, the first beam portion 102 becomes maximum when gravity is applied in the direction of 109, and the second beam portion 104 becomes 110
The amount of strain becomes maximum when gravity is applied in the direction of. In the present embodiment, the first beam portion 102 causes the strain amount by the electromotive force of the piezoelectric body which is the detection portion 108 formed on both sides of the strain neutral surface, and the second beam portion 104 causes the second beam portion 104 An electrode (not shown) provided on the opposite surface of the weight portion 103 of the second weight portion 10 and the second weight portion 10
The amount of strain was determined by detecting the change in capacity between 3 and 4. The first beam 102 has a length of 2 mm and a width of 100.
μm, the length of the second beam portion 104 is 1 mm, and the width is 10 μm
And

Here, a method of manufacturing the attitude sensor of this embodiment will be described with reference to FIGS. In FIG. 2, 201 is a silicon nitride film, 202 is a silicon (111) surface, 203 is a silicon (100) surface, 204 is an etching portion for forming a second beam portion, 205 is a vertical etching surface, 206 is an etching portion, Reference numeral 207 is a glass portion, 208 is an electrode portion, and 209 is a piezoelectric body portion.

In this embodiment, the silicon substrate 105
As the substrate, an n-type single crystal silicon substrate having a thickness of 4 mm and a <100> orientation was used, and the structure was integrally formed by anisotropic etching. In FIG. 2A, the single crystal substrate 105
L made from dichlorosilane and ammonia gas
The silicon nitride film 201 is formed into a thin film with a PCVD film forming method.
It was deposited to a thickness of 2 μm.

Next, the silicon nitride film in the voids 107 to be etched and removed on both surfaces of the substrate is removed by a photolinography method using a double-sided mask aligner device. still,
The removal of the silicon nitride film was performed by a reactive ion etching method using carbon tetrafluoride.

Next, this substrate was etched with a potassium hydroxide aqueous solution heated to about 110 ° for a desired time, and then, as shown in FIG.
The state of (b) was obtained. Here, the (111) crystal plane 202 of silicon appears due to the difference in etching rate between the (100) plane 203 of silicon and the crystal plane. Here, a part of the silicon nitride film is removed by using the above method, and etching 204 for forming the second beam portion is formed.

Next, etching was performed again with the heated potassium hydroxide aqueous solution to form the structure shown in FIG. 2 (d). In FIG. 2D, the second beam portion 104 has a time period during which a substantially vertical cross section is obtained by etching other etching portions and a time period during which a desired thickness of the second beam portion is obtained during etching. By making them coincident with each other, a desired structure can be formed. Further, in the present embodiment, an aqueous potassium hydroxide solution was used as the etching solution,
An etching solution that exhibits anisotropic etching of silicon such as hydrazine, ammonia, and tetramethylammonium hydroxide can be used.

Next, as shown in FIG. 2 (e), the portion other than the frame portion 106 on the back surface of the substrate was etched to a depth of 1 μm. In addition, sulfur hexafluoride gas was used for etching,
It was formed by the reactive ion sputtering method.

Next, as shown in FIG. 2F, the glass portion 2 formed on the surface for the second weight portion 103 and having the electrode portion 208 for detecting the strain of the second beam portion 104 is formed.
07 and the silicon frame part 207 were joined. Corning # 7059 (trademark: Corning) was used for the glass, and the anodic bonding method was used for the bonding.

Next, as shown in FIG. 2 (g), zinc oxide 20 which is a piezoelectric body of a detecting portion for detecting the strain amount of the first beam portion 20.
9 was formed using the sputtering method. Zinc oxide 20
Gold electrodes (not shown) are formed on the upper and lower sides of 9 by a vacuum vapor deposition method, and the two gold electrodes are connected to respective extraction electrode portions (not shown).

Here, the first beam portion for detection 102 which is distorted in the direction of 109 depending on the orientation of the sensor is bounded by the neutral plane.
The detection unit 108 expands and contracts and expands and contracts on both sides to generate opposite electric potentials. At this time, by determining one output voltage and adding both voltages, the strain of the beam due to gravity can be detected. Further, by determining the output directions of the two potentials, it is possible to detect extension and expansion and contraction, and to detect which is higher.

Now, a method for extracting signals from the attitude sensor of this embodiment will be described with reference to FIG. In FIG. 3, 301 is a posture sensor, 302 is a capacitance-voltage conversion circuit, 303 and 305 are low-pass film circuits, 304 and
Reference numerals 306 and 307 denote comparison circuits.

The voltage signal from the detecting portion 108 of the first beam portion 102 and the capacitance signal from the second both portions 104 are the capacitance −
After being converted into a voltage signal by the voltage conversion circuit 302, high-frequency components are removed by the low-pass filters 305 and 303. With this low-pass filter, a signal associated with the natural frequency of the beam can be removed, and the posture can be detected stably even when acceleration such as impact is applied. The signals that have passed through the low-pass filters 305 and 303 are compared with a preset voltage value in the comparison circuit 304, and it is determined whether the 109 and 110 directions are downward. Based on these two binary outputs, the comparison circuit 307 determines and outputs the posture direction.
In this embodiment, the comparison circuit 307 has 109 directions, 1
Three types of outputs other than 10 directions and 2 directions were output.

Next, an example in which this embodiment is used for the attitude sensor of the camera will be described with reference to FIGS. FIG. 4 shows a camera using the attitude sensor of this embodiment, and FIG. 5 shows the viewfinder of this camera.

In FIGS. 4 and 5, 401 is a camera,
Reference numeral 402 is a part of the flexible substrate, 403 is a posture sensor, 501 is a finder frame, 502 is a display area in the finder, and 503 to 507 are displays showing an autofocus measurement distance area.

As shown in FIG. 4, in this embodiment, the attitude sensor 403 is fixed to the flexible substrate 402, detects the attitude of the camera when the camera is held in the horizontal position and the vertical position, and controls the camera. A signal is output to the system to support various shooting conditions.

A mode for automatically changing the selection of the measurement distance point at the vertical position and the horizontal position during autofocus will be described with reference to FIG. FIG. 5 (a) is a lateral position, FIG. 5 (b)
Indicates the vertical position. Three points 506, 504, and 507 are selected in the horizontal position, and three points 503, 504, and 505 are selected in the vertical position so that the focusing probability of autofocus is improved. Also, in the evaluation measurement using the divided sensor, it is possible to increase the probability of obtaining proper exposure by changing the conditions of the vertical position and the horizontal position.

Next, another form of the attitude sensor of this embodiment will be described with reference to FIG. In FIG. 6, 601 is a first weight portion, 602 is a first beam portion for detection, 603 is a second weight portion, 604 is a second beam portion for detection, 605 is a silicon single crystal substrate, 606. Is a frame portion, 607 is a void portion formed by etching removal, and 608 is a detection portion.

In this embodiment, the first beam portion 602 has two
The book has a structure that does not easily twist with respect to external force. Note that the detection unit (not shown) is formed in the same manner as the above-described attitude sensor, the detection unit of the first beam unit 602 is also formed of two beams, and is the sum of the output values of the two beams. Is taking. Also in this form, the posture could be sensed similarly to the above-mentioned sensor.

Further, in this embodiment, the means for detecting the amount of strain is detected by the potential generated by the strain of the piezoelectric body for the first beam portion and by the change in the capacitance for the second beam portion. However, other means for detecting strain such as a piezoresistive element and an optical iron method can be applied.

(Embodiment 2) FIGS. 7 and 8 show a second embodiment of the attitude sensor of the present invention, and FIG. 7 is a structural portion of the attitude sensor of the second embodiment of the present invention. , FIG. 8 is FIG.
It is a figure which shows the example which used the attitude | position sensor of this Example for the input device of a notebook computer.

In FIG. 7, 701 is a first weight portion, 7
Reference numeral 02 is a first beam portion for detection, 703 is a second weight portion, 7
Reference numeral 04 is a second beam portion for detection, 705 is a silicon single crystal substrate, 706 is a frame portion, 707 is a void portion formed by etching removal, 708 is a third weight portion, 709 is a third beam portion, Reference numerals 710, 711, and 712 are strain directions of the first to third beams, and 713 is a detection unit.

The attitude sensor of this embodiment was manufactured by using the same method as that of the first embodiment. In addition, the first beam portion 702
The detecting portion 713 of the third beam portion 709 was made of zinc oxide using the same method as in the first embodiment. At this time, in the present embodiment, the formation region was only on one side of the beam. In this embodiment, it is possible to detect postures in three directions by using the same signal detecting means as in the first embodiment.

Next, an example in which the attitude sensor of this embodiment is used as an input device of a computer will be described with reference to FIG. In FIG. 8, reference numeral 801 denotes a computer capable of multitasking, 8
02 is screen A, 803 is screen B, 804 is screen C, 80
Reference numeral 5 is an input device, 806 is an on / off switch, and 807 is a trackball. In FIG. 8, this input device 805
When the attitude of the input device is changed and the on / off switch 806 is pressed within 1 sec, the attitude sensor is incorporated in the switch to switch the screen A to the screen C in accordance with the attitude in the directions of 710, 711, and 712. I did it. The input device according to the present embodiment enables smooth movement of tasks, and in particular, enables easy and favorable input even in a place with a lot of vibration such as a train or a ship or a place where the use space is limited.

(Embodiment 3) FIGS. 9 to 11 are views showing a third embodiment of the present invention, FIG. 9 is a perspective view of an attitude sensor, FIG. 10 is a view showing a detecting portion of the attitude sensor, FIG. 11 is a diagram showing a signal processing method.

9 and 11, 901 is a weight portion, 902 is a first beam portion for detection, 903 is a second beam portion for detection, 904 is a silicon single crystal substrate, 905 is a frame portion, and 906. Is a void formed by etching removal, 90
6 to 908, the strain direction of the beam, 1001 to 1004, the detection unit formed on the first beam portion, and 1005 to 1012, the detection units 1101 and 1104 formed on the second beam portion.
Is an addition circuit, 1102 and 1105 are addition and inversion circuits 1103, 1106, and 1107 are addition and comparison circuits. In the present embodiment, the postures in the three axis directions can be detected by the signal processing of the detection unit formed on the two beams.

The attitude sensor shown in FIGS. 9 and 10 is made of single crystal silicon by the same method as that of the embodiment, and the detecting portions 1001 to 1012 are made of zinc oxide. Each of the detection units 1001 to 1012 is formed on the beam at a position equivalent to one side with respect to the neutral plane of the beam. Also, the first beam portion 902 has 906 and 907.
The second beam portion 903 has a structure in which the second beam portion 903 is easily distorted in the direction 908.

Next, the three-direction posture detection method in this embodiment will be described with reference to FIG. FIG. 11 (a)
In, the signals of the detection units 1001 to 1004 are passed through a low-pass filter (not shown), and then 1101 and 1
After being added by the circuit of 102, only the added signals of 1103 and 1104 are inverted to match the output directions with respect to the distortion. Next, after being added in the circuit of 1103, it is compared with the set value and it is determined whether or not there is a sensor in the direction of 908. Similarly, the strain in the 906 direction in FIG. 11B and the strain in the 907 direction in FIG. 11C were detected and the orientation of the sensor was determined. When this embodiment is used for the input device described in the second embodiment, as in the second embodiment,
It worked well.

In this embodiment, the posture signal is output only when it is judged that only one of these three signals is in that direction, and the sensor outputs in two or more directions due to impact or the like. If it is determined that there is a distortion direction of, the signal is invalidated.

[0040]

As described above, according to the present invention, it is possible to provide a posture sensor capable of detecting posture changes in multiple directions. Further, by processing the silicon substrate by using the photolinography method and the etching technique, there is an effect that the miniaturization of the sensor and the high mass productivity can be realized at the same time due to the improvement of the processing accuracy which was difficult by the conventional mechanical processing.

Further, since no constituent material such as mercury which has a problem in safety and environment is used, it can be used in a wide variety of fields.

[Brief description of drawings]

FIG. 1 is a structural diagram of a posture sensor according to a first embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of the attitude sensor according to the first embodiment of the present invention.

FIG. 3 is a block diagram illustrating a signal processing method of the attitude sensor according to the first embodiment of this invention.

FIG. 4 is an explanatory diagram when a posture sensor according to the first embodiment of the present invention is used for a camera.

FIG. 5 is an explanatory diagram when a posture sensor according to the first embodiment of the present invention is used for a camera.

FIG. 6 is a structural diagram of a posture sensor of another form according to the first embodiment of the present invention.

FIG. 7 is a structural diagram of a posture sensor according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating an input device using an attitude sensor according to a second embodiment of the present invention.

FIG. 9 is a structural diagram of a posture sensor according to a third embodiment of the present invention.

FIG. 10 is a diagram showing a detection unit of an attitude sensor.

FIG. 11 is a diagram showing a signal processing method.

FIG. 12 is a diagram for explaining a conventional attitude sensor.

[Explanation of symbols]

101, 601, 701, 901 1st weight part 102, 602, 702, 902 1st detection beam part 103, 603, 703 2nd weight part 104, 604, 704, 903 2nd detection beam part 105, 605, 705, 904 Silicon single crystal substrate 106, 606, 706, 905 Frame portion 107, 607, 707, 906 Void portion formed by etching removal 108, 608, 713, 1001 to 1012 Strain detection portion 109, 110,710,711,712,907,9
08,909 Strain direction 201 Silicon nitride film 202 Silicon (111) surface 203 Silicon (100) surface 204 Etching portion for forming second beam portion 205 Vertical etching surface 206 Etching portion 207 Glass portion 208 Electrode portion 209 Piezoelectric body portion 301 Attitude sensor 302 Capacitance-voltage conversion circuit 303, 305 Low-pass filter circuit 304, 306, 307 Comparison circuit 401 Camera 402 Part of flexible substrate 403 Attitude sensor 501 Viewfinder frame 502 Display area in viewfinder 503 to 507 Autofocus measurement distance area 708 No. Weight part 709 Third beam part 801 Computer 802, 803 Task screen 805 Input device 806 ON / OFF switch 807 Trackball 1101, 1104 Adder circuit 1102, 110 Addition and inversion circuit 1103,1106,1107 addition and comparison circuit

Claims (3)

[Claims] 1. A first beam part having a structure that is easily strain-deformed in a specific direction, and a structure that is coupled to the first beam part and is easily strain-deformed in a direction different from the deformation direction of the first beam part. A structure that is composed of at least one or more beam portions, and each beam portion is integrally formed by etching a substrate, and has a detection portion that detects the amount of strain of each beam portion. The posture sensor, which detects the orientation of the sensor by comparing the signal values of the strain signals of the signal after passing through the low-pass filter. 2. The attitude sensor according to claim 1, wherein a direction in which the first beam portion is likely to be strained and deformed is substantially parallel to an etching surface of the base body. 3. The attitude sensor according to claim 1, wherein the base is a silicon single crystal substrate.