US20070247032A1 - Crystal Device and Method for Manufacturing Crystal Device - Google Patents
Crystal Device and Method for Manufacturing Crystal Device Download PDFInfo
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- US20070247032A1 US20070247032A1 US11/630,154 US63015405A US2007247032A1 US 20070247032 A1 US20070247032 A1 US 20070247032A1 US 63015405 A US63015405 A US 63015405A US 2007247032 A1 US2007247032 A1 US 2007247032A1
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- 239000013078 crystal Substances 0.000 title claims abstract description 274
- 238000000034 method Methods 0.000 title claims description 36
- 238000004519 manufacturing process Methods 0.000 title claims description 30
- 239000000758 substrate Substances 0.000 claims abstract description 53
- 238000005530 etching Methods 0.000 claims abstract description 30
- 238000000059 patterning Methods 0.000 claims description 12
- 230000005855 radiation Effects 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 5
- 238000005260 corrosion Methods 0.000 claims description 3
- 230000007797 corrosion Effects 0.000 claims description 3
- 238000010586 diagram Methods 0.000 description 35
- 230000000694 effects Effects 0.000 description 6
- 230000005684 electric field Effects 0.000 description 6
- 238000001514 detection method Methods 0.000 description 5
- 239000011651 chromium Substances 0.000 description 4
- 239000010931 gold Substances 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 238000005452 bending Methods 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- QZPSXPBJTPJTSZ-UHFFFAOYSA-N aqua regia Chemical compound Cl.O[N+]([O-])=O QZPSXPBJTPJTSZ-UHFFFAOYSA-N 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 238000010295 mobile communication Methods 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
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Classifications
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/21—Crystal tuning forks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/42—Piezoelectric device making
Definitions
- the present invention relates to a crystal device comprising a base and a plurality of vibrating prongs protruding from the base, and a fabrication method for the same; more particularly, the invention relates to a tuning-fork type crystal gyro to be used as an angular velocity sensor, and a fabrication method for the same.
- HDDs Hard Disk Drives
- mobile computers portable telephones, car telephones, and other mobile communication apparatus
- crystal oscillators used in these products.
- FIG. 14 is a diagram showing the structure of a prior art tuning-fork type crystal device.
- the structure of the prior art tuning-fork type crystal device will be described below (for example, refer to Patent Document 1).
- the prior art tuning-fork type crystal device 2 comprises: a tuning-fork-shaped crystal plate 11 having a base 2 a formed from a crystal and vibrating prongs 2 b protruding the base; and electrodes 501 and 511 for generating an electric field across the crystal plate 11 .
- the vibrating prongs 2 b each refer to the portion from the tip to the first bend of the fork just before the base 2 a thereof, and the base 2 a refers to the portion beyond the bend.
- a prescribed electric field can be produced across the crystal plate 11 by applying different potentials to the respective electrodes 501 and 511 . Since the crystal plate 11 is a piezoelectric material, when an electric field is applied across the plate the plate contracts or expands according to the direction of the electric field. As a result, the vibrating prongs 2 b of the crystal plate 11 vibrate, and the structure can thus be used as a crystal oscillator 2 .
- FIG. 16 is a diagram showing part of the fabrication process of the prior art tuning-fork type crystal device.
- a crystal substrate 15 is prepared by forming mask layers 21 and 22 and resist layers 31 and 32 one on top of the other on both the upper and lower surfaces of the substrate.
- the resist layers 31 and 32 formed on both surfaces of the crystal substrate 15 are exposed to UV radiation of prescribed wavelength through masks 41 of the same mask pattern 41 a .
- the resist layers 31 and 32 are exposed only in portions where the mask pattern 41 a is not formed.
- the resist layers 31 and 32 are developed as shown in FIG. 16B , forming resist layer patterns 31 b and 32 b .
- the resist layer patterns 31 b and 32 b are each formed in the same shape as the mask pattern 41 a of the mask 41 .
- the mask layers 21 and 22 are etched as shown in FIG. 16C , forming mask layer patterns 21 b and 22 b .
- the mask layer patterns 21 b and 22 b are each formed in the same shape as the mask pattern 41 a of the mask 41 .
- the resist layer patterns 31 b and 32 b are removed as shown in FIG. 16D .
- the crystal substrate 15 is etched as shown in FIG. 16E , thus producing the outer shape of the crystal plate 11 .
- FIG. 17 is a diagram showing the shape of the crystal plate formed by the prior art etching and the shapes of the mask layer patterns for comparison.
- the major faces 211 and 221 of the crystal plate 11 formed by the etching in FIG. 16E which were the plane surfaces of the crystal substrate 15 , are formed in substantially the same shapes as the respective mask layer patterns 21 b and 22 b . Since the mask layers 21 b and 22 b are both substantially the same in shape as the mask pattern 41 a , it follows that the two major faces 211 and 221 of the crystal plate 11 are both formed in substantially the same shape.
- the mask layer patterns 21 b and 22 b are removed, and the electrodes 501 and 511 are formed, completing the fabrication of the tuning-fork type crystal device 2 shown in FIG. 14 .
- the structure and the fabrication method of the tuning-fork type crystal device according to the prior art described above are used for crystal resonators, crystal oscillators, crystal gyros, and various other applications.
- the crystal plate 11 In the prior art tuning-fork type crystal device, it is common practice to form the crystal plate 11 by etching. However, since the crystal has the property that its reaction rate differs depending on the direction it is etched (this property is generally called the anisotropic etching property), a ridge-like unetched portion 111 projecting from a side face is necessarily formed, as shown in FIG. 14 , in an intermediate region of the base 2 a connecting between the vibrating prongs 2 b , that is, in FIG.
- the portion that originates from the tip of one vibrating prong 2 b passes through the root of the one vibrating prong 2 b and through the root of the other vibrating prong 2 b , and leads to the tip of that other vibrating prong 2 b (this portion is generally referred to as the crotch portion).
- the vibrating prong 2 b which should normally vibrate in the X-axis direction vibrates in a direction slightly tilted toward the Z-axis direction as indicated by W 1 .
- the vibration W 1 produced by tilting toward the Z-axis direction tends to tilt greater toward the Z-axis direction as the unetched portion 111 becomes larger.
- FIG. 15 is a diagram showing an enlarged view and a side view of the crotch portion of the tuning fork and its adjacent regions in the prior art tuning-fork type crystal device.
- FIG. 15 ( b ) shows the shape of the side face as viewed from the direction C in FIG. 15 ( a ).
- the unetched portion 111 is formed on the side face of the crystal plate 11 in the shape of a ridge extending obliquely from one major face 211 to the other major face 221 of the crystal plate 11 .
- the root refers to the portion at the boundary between the vibrating prong 2 b and the base 2 a ; in FIG. 15 ( a ), the bend corresponds to the root.
- the unetched portion 111 left after the etching is formed only on one vibrating prong side of the crotch portion of the tuning fork, and as a result, the left and right vibrating prongs 2 b vibrate in different directions, as shown in FIG. 14 .
- the resulting crystal device is often unstable and inaccurate in operation; in the prior art, therefore, the balance between the directions of vibration has been adjusted after forming the crystal plate 11 , by performing an additional processing step for appropriately removing portions of the electrodes 501 and 511 and the crystal plate 11 .
- Patent Document 1 One proposal has been made in Patent Document 1 to stabilize the vibration of the crystal device.
- the proposal made in Patent document 1 aims to stabilize the vibration of the crystal device by optimizing the plan shape of the crystal plate 11 according to Patent Document 1, it is stated that the plan shape of one major face 201 is the same as the plan shape of the other major face 211 .
- the vibration tilted toward the Z axis such as the vibration W 1 shown in FIG. 14 becomes a very serious problem.
- the Z-axis direction is nothing but the direction of the angular velocity to be detected, and any vibration in the Z-axis direction, such as the vibration W 1 , can affect the accurate detection of the angular velocity.
- the prior art crystal gyro has had the problem of low accuracy and low reliability.
- Patent Document 1 Japanese Unexamined Patent Publication No. H10-41772 (page 2, FIGS. 2 and 3)
- a crystal device has a crystal plate that includes a base and a plurality of vibrating prongs protruding from the base, wherein two major faces, each containing the base and the plurality of vibrating prongs, are formed on the crystal plate, and wherein the two major faces have respectively different outer shapes.
- a crystal device has a first major face, which contains a portion of the base and a portion of the vibrating prong within a single plane, and a second major face, which contains another portion of the base and another portion of the vibrating prong within a single plane, are formed on the crystal plate, wherein the first major face and the second major face have different outer shapes.
- the crystal plate includes at least a first vibrating prong and a second vibrating prong.
- the first and second major faces each have a crotch portion defined by a line that originates from the tip of the first vibrating prong, passes through the root of the first vibrating prong and through the root of the second vibrating prong, and leads to the tip of the second vibrating prong, wherein the crotch portion of the first major face and the crotch portion of the second major face have different shapes.
- the number of bends contained in the crotch portion of the first major face is different from the number of bends contained in the crotch portion of the second major face.
- the angle of a bend contained in the crotch portion of the first major face is different from the angle of a bend contained in the crotch portion of the second major face.
- the number of center points representing curved sections contained in the crotch portion of the first major face is different from the number of center points representing curved sections contained in the crotch portion of the second major face.
- the curvature of a curved section contained in the crotch portion of the first major face is different from the curvature of a curved section contained in the crotch portion of the second major face.
- a method for manufacturing a crystal device includes the steps of forming a resist layer made of a photosensitive material and a mask layer having corrosion resistance to etching of a crystal on each of two plane surfaces of a crystal substrate, exposing the resist layer formed on one plane surface of the crystal substrate to radiation through a first mask on which a first mask pattern of a prescribed shape is drawn and exposing the resist layer formed on the other plane surface of the crystal substrate to radiation through a second mask on which a second mask pattern is drawn that differs in shape from the first mask pattern, forming a first resist layer pattern by patterning the resist layer on the one plane surface of the crystal substrate into a shape corresponding to the first mask pattern, and forming a second resist layer pattern by patterning the resist layer on the other plane surface of the crystal substrate into a shape corresponding to the second mask pattern, forming a first mask layer pattern by patterning the mask layer on the mask layer on
- the method according to the present invention includes the steps of forming a resist layer made of a photosensitive material and a mask layer having corrosion resistance on each of two plane surfaces of a crystal substrate, exposing the resist layer formed on the first plane surface of the crystal substrate to radiation through a first mask on which a first mask pattern is drawn and exposing the resist layer formed on the second plane surface of the crystal substrate to radiation through a second mask on which a second mask pattern is drawn that differs in shape from the first mask pattern, forming a first resist layer pattern by patterning the resist layer on the first plane surface of the crystal substrate into a shape corresponding to the first mask pattern and forming a second resist layer pattern by patterning the resist layer on the second plane surface of the crystal substrate into a shape corresponding to the second mask pattern, forming a first mask layer pattern by patterning the mask layer on the first plane surface of the crystal substrate into a shape corresponding to the first mask pattern and forming a second mask layer pattern by patterning the mask layer on the second plane surface of the crystal substrate into a shape corresponding to the
- the first mask layer pattern has an outer shape that contains a portion of the base and a portion of the vibrating prong within a single plane
- the second mask layer pattern has an outer shape that contains another portion of the base and another portion of the vibrating prong within a single plane.
- the crystal plate includes at least a first vibrating prong and a second vibrating prong.
- the first and second mask layer patterns each have a crotch portion defined by a line that originates from the tip of the first vibrating prong, passes through the root of the first vibrating prong and through the root of the second vibrating prong, and leads to the tip of the second vibrating prong.
- the crotch portion of the first mask layer pattern and the crotch portion of the second mask layer pattern have different shapes.
- the number of bends contained in the crotch portion of the first mask layer pattern is different from the number of bends contained in the crotch portion of the second mask layer pattern.
- the angle of a bend contained in the crotch portion of the first mask layer pattern is different from the angle of a bend contained in the crotch portion of the second mask layer pattern.
- the number of center points representing curved sections contained in the crotch portion of the first mask layer pattern is different from the number of center points representing curved sections contained in the crotch portion of the second mask layer pattern.
- the curvature of a curved section contained in the crotch portion of the first mask layer pattern is different from the curvature of a curved section contained in the crotch portion of the second mask layer pattern.
- One feature of the crystal device according to the present invention is that the two major faces of the crystal plate have different outer shapes, in particular, the crotch portions of the respective major faces have different shapes.
- the vibration of the (tuning-fork type) crystal plate can be stabilized, and as a result, a crystal device having high reliability and high accuracy can be achieved.
- the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity of the crystal device can be increased compared with the prior art.
- the vibration can be stabilized, and therefore, the angular velocity can be detected accurately; as a result, a crystal gyro can be obtained that have high detection sensitivity and high accuracy.
- a crystal device having stable vibration characteristics can be formed, and as a result, a crystal device having high reliability and high accuracy can be produced.
- the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity can be increased.
- FIG. 1 is a diagram showing the structure of a crystal device 1 according to the present invention.
- FIG. 2 is a diagram showing an enlarged view and a side view of a crotch portion and its adjacent regions in the crystal device 1 according to the present invention.
- FIG. 3 is a diagram showing the first half of the manufacturing process of the crystal device 1 according to the present invention.
- FIG. 4 is a diagram showing the second half of the manufacturing process of the crystal device 1 according to the present invention.
- FIG. 5 is a diagram showing the shape of a crystal plate 10 and the shapes of mask layer patterns in the crystal device 1 according to the present invention.
- FIG. 6 is a diagram showing the etching characteristic of a crystal substrate formed from a conventional synthetic crystal.
- FIG. 7 is a diagram showing mask patterns used in the manufacturing process of the crystal device 1 according to the present invention.
- FIG. 8 is a diagram showing mask patterns used in the manufacturing method for an alternative crystal device 2 according to the present invention.
- FIG. 9 is a diagram showing the shape of a crystal plate 12 and the shapes of mask layer patterns in the alternative crystal device 2 according to the present invention.
- FIG. 10 is a diagram showing mask patterns used in the fabrication method for a further alternative crystal device 3 according to the present invention.
- FIG. 11 is a diagram showing the shape of a crystal plate 13 and the shapes of mask layer patterns in the further alternative crystal device 3 according to the present invention.
- FIG. 12 is a diagram showing mask patterns used in the manufacturing method for a still further alternative crystal device 4 according to the present invention.
- FIG. 13 is a diagram showing the shape of a crystal plate 14 and the shapes of mask layer patterns in the still further alternative crystal device 4 according to the present invention.
- FIG. 14 is a diagram showing the structure of a prior art tuning-fork type crystal device.
- FIG. 15 is a diagram showing an enlarged view and a side view of the crotch portion of a tuning fork and its adjacent regions in the prior art tuning-fork type crystal device.
- FIG. 16 is a diagram showing part of the manufacturing process of the prior art tuning-fork type crystal device.
- FIG. 17 is a diagram showing the shape of the crystal plate formed by etching according to the prior art and the shapes of mask layer patterns for comparison.
- FIG. 1 is a diagram showing the structure of a crystal device 1 according to the present invention.
- the crystal device 1 comprises a crystal plate 10 formed from a crystal, and electrodes 500 and 510 .
- the crystal plate 10 is formed in the shape of a tuning fork which is made up of a base 1 a and a plurality of vibrating prongs 1 b protruding from the base 1 a .
- the electrodes 500 and 510 are electrically separated from each other, and an electric field can be produced across the crystal plate 10 by applying different potentials to the respective electrodes. Since the crystal plate 10 is a piezoelectric material, the plate contracts or expands according to the direction of the applied electric field; this contracting/expanding motion causes the vibrating prongs 1 b to vibrate. When a voltage is applied between the electrodes 500 and 510 of the crystal device 1 , the two vibrating prongs 1 b produce vibrations W 0 along the X-axis direction.
- the portion defined by an outline extending from the tip to the first bend in the direction of the base will hereinafter be referred to as the “vibrating prong”, the portion beyond the bend will be referred to as the “base”, and the portion at the boundary between the base and the vibrating prong will be referred to as the “root”.
- the difference between the crystal device 1 of the present invention shown in FIG. 1 and the tuning-fork type crystal device of the prior art lies in the outer shape of the crystal plate 10 , especially in the shapes of the two major faces 210 and 220 formed by the plane faces of the base 1 a and vibrating prongs 1 b of the crystal plate 10 .
- the shape of the major face 210 is different from the shape of the major face 220 , especially in the intermediate region connecting between the two vibrating prongs (that is, in FIG.
- the portion that originates from the tip of one vibrating prong 1 b passes through the root of the one vibrating prong 1 b and through the root of the other vibrating prong 1 b , and leads to the tip of that other vibrating prong 1 b (this portion is hereinafter referred to as the “crotch portion”)).
- the shape of the crotch portion of the major face 210 contains three bends
- the shape of the crotch portion of the major face 220 contains two bends (one of the two bends of the major face 220 is hidden from view in FIG. 1 ).
- the two major faces 210 and 220 are not formed so as to have differently shaped crotch portions as described above, but are always formed in the same shape.
- the collateral effect is that the shape of the crystal plate (the shape of the unetched portion 110 formed on a side face of the crotch portion of the crystal plate 10 ) can be made different from that of the prior art.
- stable vibration characteristics such as the vibrations W 0 along the X axis shown in FIG. 1 can be obtained by forming the unetched portion 110 in an optimum shape.
- FIG. 2A is an enlarged view of the crotch portion and its adjacent regions in the tuning-fork type crystal device 1 shown in FIG. 1
- FIG. 2B is a diagram showing the shape of the side face as viewed from the direction B in FIG. 2A .
- the unetched portion 110 of the crystal device 1 which is left on the side face of the crotch portion of the crystal plate 10 , is formed as a ridge-like protrusion having a ridge line substantially parallel to the two major faces 210 and 220 . That is, the shape of the unetched portion 110 of the crystal device 1 is different from that of the prior art which has a ridge line extending obliquely between the two major faces. Furthermore, the size of the unetched portion 110 can be reduced (to about one quarter in terms of volume ratio) compared with the prior art (in which the same mask pattern 21 b is used for both the major faces).
- the unetched portion 110 formed on the side face of the crotch portion of the crystal plate 10 can be made very small and can be formed in the shape of a protrusion having a ridge line substantially parallel to the two major faces 210 and 220 . This, therefore, does not provide any straining prop to the root portion of the vibrating prong, and the vibrating prong can produce stable vibrations W 0 along the X axis as designed.
- FIG. 3 is a diagram showing the first half of the manufacturing process of the crystal device 1
- FIG. 4 is a diagram showing the second half of the manufacturing process of the crystal device 1
- FIG. 7 is a diagram showing mask patterns used in the manufacturing process of the crystal device 1 .
- a crystal substrate 15 is prepared by forming mask layers 21 and 22 and resist layers 31 and 32 one on top of the other on the upper and lower plane surfaces of the substrate.
- the crystal substrate 15 used in the present embodiment is a substrate generally called a Z plate whose plane faces are substantially perpendicular to the crystallographic z-axis direction of the crystal (the plane faces make an angle of 85 to 95 degrees with respect to the Z axis).
- the mask layers 21 and 22 are each formed from a composite layer consisting of a chromium (Cr) film deposited to a thickness of 0.05 ⁇ m on the crystal substrate 15 and a gold (Au) film deposited to a thickness of 0.15 ⁇ m on the Cr film.
- the resist layers 31 and 32 are formed using a positive resist OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd.
- One plane surface of the crystal substrate 15 on which the mask layer 21 and the resist layer 31 are formed and the other plane surface on which the mask layer 22 and the resist layer 32 are formed are exposed to UV radiation of prescribed wavelength through masks 41 and 42 , respectively.
- the mask pattern 41 a drawn on the mask 41 and the mask pattern 42 a drawn on the mask 42 are different in shape.
- the mask pattern 41 a drawn on the mask 41 has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, as shown in FIG. 7A .
- the intermediate region (i.e., the crotch portion) connecting between the two vibrating prongs has a shape that contains three bends formed by bending a straight line.
- the mask pattern 42 a formed on the mask 42 has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, as shown in FIG. 7B .
- the intermediate region (i.e., the crotch portion) connecting between the two vibrating prongs has a shape that contains two bends formed by bending a straight line.
- the shape of the crotch portion differs between the mask pattern 41 a of the mask 41 and the mask pattern 42 a of the mask 42 ; in particular, the number of bends contained in the crotch portion differs between them.
- the resist layers 31 and 32 are developed as shown in FIG. 3B , forming resist layer patterns 31 a and 32 a .
- the resist layers are developed using a developer specially prepared for OFPR-800.
- the resist layer pattern 31 a is formed in the same shape as the mask pattern 41 a of the mask 41
- the resist layer pattern 32 a is formed in the same shape as the mask pattern 42 a of the mask 42 . That is, the resist layer pattern 31 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in the resist layer pattern 31 a has a shape that contains three bends.
- the resist layer pattern 32 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in the resist layer pattern 32 a has a shape that contains two bends.
- the mask layers 21 and 22 are etched as shown in FIG. 3C , forming mask layer patterns 21 a and 22 a .
- the mask layer patterns 21 a and 22 a are formed by etching the Au film in aqua regia and the Cr film in an etching solution of nitric acid.
- the mask layer pattern 21 a is formed in the same shape as the mask pattern 41 a of the mask 41
- the mask layer pattern 22 a is formed in the same shape as the mask pattern 42 a of the mask 42
- the mask layer pattern 21 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs
- the crotch portion connecting between the two vibrating prongs in the mask layer pattern 21 a has a shape that contains three bends.
- the mask layer pattern 22 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in the mask layer pattern 22 a has a shape that contains two bends.
- the mask layer patterns 21 a and 22 a are formed in different shapes on the respective plane surfaces of the crystal substrate 15 .
- OFPR-800 used for forming the resist layer patterns 31 a and 32 a is removed using acetone.
- FIG. 4A is a diagram showing the mask layer patterns 21 a and 22 a formed in different shapes, as described above, on the plane surfaces of the crystal substrate 15 .
- the A-A cross section of FIG. 4A is shown in FIG. 3D .
- the crystal plate 10 whose outer shape is defined by the mask layers 21 a and 22 a , and whose one major face is differently shaped than its other major face, is completed as shown in FIG. 4B .
- FIG. 5 is a diagram showing the shape of the crystal plate 10 used in the crystal device 1 according to the present invention and the shapes of the mask layer patterns for comparison.
- one major face 210 of the crystal plate 10 is formed in substantially the same shape as the mask layer pattern 21 a , and has an outer shape defined by the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs has a shape that contains three bends.
- the other major face 220 of the crystal plate 10 is formed in substantially the same shape as the mask layer pattern 22 a , and has an outer shape defined by the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs has a shape that contains two bends. Accordingly, in the present embodiment, the shape of the one major face 210 of the crystal plate 10 is different from that of the other major face 220 .
- the crystal plate 10 formed by etching in FIG. 4B has an unetched portion 110 left unetched on the side face of the crotch portion connecting between the two vibrating prongs. This is due to the etching characteristic peculiar to the crystal.
- the crystal has the characteristic that its etch rate varies with its crystal orientation; this characteristic is generally known as the anisotropic etching characteristic.
- a protrusion such as the unetched portion 110 is necessarily formed on the side face of the crotch portion of the crystal plate 10 because of the effect of the anisotropic etching characteristic of the crystal.
- the size of the unetched portion 110 can be greatly reduced compared with the prior art, because the shapes of the mask layer patterns 21 a and 22 a are determined by considering the anisotropic etching of the respective major faces, that is, for portions where the etch rate is slow, the patterns are formed with larger aperture in order to make such portions easier to etch but, for portions where the etch rate is fast, the patterns are formed with smaller aperture in order to make it difficult for the etching to proceed.
- the unetched portion 110 can be formed in a different shape than that of the prior art, that is, in the shape of a ridge-like protrusion having a ridge line substantially parallel to the two major faces 210 and 220 . This is also the effect of the shapes of the mask layer patterns 21 a and 22 a.
- the shapes of the mask layer patterns 21 a and 22 a are differently designed for the respective major faces by considering the anisotropic etching of the crystal. This also constitutes a feature of the present invention.
- the mask layer patterns 21 a and 22 a are removed, and the electrodes 500 and 511 are formed, to complete the fabrication of the tuning-fork type crystal device as shown in FIG. 1 .
- the tuning-fork type crystal device 1 according to the present invention can be very effectively used for crystal gyros.
- the Z-axis direction (the direction parallel to the Z axis which is one of the crystallographic axes of the crystal) is perpendicular to the vibration direction of the vibrating prongs, and is nothing but the direction of the angular velocity to be detected.
- the tuning-fork type crystal device 1 as can be seen in the vibrations W 0 , hardly any vibrations occur in the Z-axis direction, so that only the component of the angular velocity to be detected can be accurately detected.
- a crystal gyro can be achieved that has very good detection sensitivity and high reliability compared with the prior art.
- the direction of the angular velocity to be detected is perpendicular to the vibration direction of the vibrating prongs, and the angular velocity cannot be detected accurately unless the vibration direction is stable as designed.
- the angular velocity perpendicular to the vibration direction can be accurately detected, because the vibration direction is stable as designed.
- the unetched portion remaining on the side face of the crotch portion of the crystal plate can be made very small.
- the unetched portion can be formed in the shape of a protrusion having a ridge line substantially parallel to the two major faces.
- the unetched portion can be formed parallel to the major faces of the crystal plate in such a manner as to be substantially centralized on the side face of the crotch portion. In this way, the unetched portion whose shape is significantly different from that of the prior art constitutes a feature of the present invention.
- the unetched portion 111 was formed in a ridge-like shape on the side face of the crotch portion in such a manner as to extend across the side face of the crystal plate obliquely from one major face to the other major face (see FIG. 15B ). This produced the same effect as if a prop had been placed obliquely across the root portion of the vibrating prong, causing the vibrating prong to vibrate in a direction tilted toward the Z-axis direction.
- the unetched portion 110 is small in size, and is formed parallel to the major faces of the crystal plate in such a manner as to be substantially centralized on the side face of the crotch portion, as described above, the root portion of the vibrating prong is not physically strained, and the desired stable vibrations can be produced.
- the unetched portion 110 is formed when the crystal substrate is etched.
- the shape of the unetched portion 110 is substantially determined by the shapes of the mask layer patterns formed in the step that precedes the etching step.
- the shape of the unetched portion 110 in the crystal device 1 of the present invention is achieved by making the shape of the mask layer pattern different between the upper and lower surfaces of the crystal substrate. This utilizes the etching characteristic that the etch rate differs between the upper and lower surfaces of the crystal substrate.
- FIG. 6 is a diagram showing the etching characteristic of the crystal substrate formed from a conventional synthetic crystal.
- the crystal substrates 15 shown in FIGS. 6A and 6B are each a substrate cut so as to have plane faces substantially perpendicular to the crystallographic z axis (the thus cut substrate is generally called a “Z plate”).
- the growth direction “g” of the crystal in the crystal substrate of FIG. 6A is opposite to the growth direction “g” of the crystal in the crystal substrate of FIG. 6B . That is, FIGS. 6A and 6B represent the relationship between the front and back of the crystal substrate.
- the etch rates e 1 in directions parallel to the Y axes and the etch rate e 2 in directions normal to the Y axes are different between the case of FIG. 6A and the case of FIG. 6B .
- the etch rate e 1 in the direction parallel to the Y axis (Y 1-1 ) and the etch rate e 2 in the direction normal to the Y axis (Y 1-2 ) have the relationship defined by e 1 >e 2 .
- the etch rate e 1 in the direction parallel to the Y axis (Y 2-1 ) and the etch rate e 2 in the direction normal to the Y axis (Y 2-2 ) have the relationship defined by e 1 ⁇ e 2 .
- the upper face 210 of the crystal plate 10 shown in FIG. 5 is formed as shown in FIG. 6A , and that the three Y axes (Y 1-1 to Y 1-3 ) in FIG. 6A are arranged as shown in FIG. 5 .
- the direction e 2 at right angles to the Y 1-2 axis substantially coincides with the projecting direction of the unetched portion 110 . Since the etching is difficult to proceed in the direction e 2 , the unetched portion is formed in the direction e 2 .
- FIG. 8 is a diagram showing a combination of mask patterns for an alternative crystal device 2 according to the present invention.
- the tuning-fork type crystal device 2 is fabricated by using mask patterns 41 b and 42 b having different bend angles ( ⁇ 1 and ⁇ 2 ) as shown in FIGS. 8A and 8B .
- the fabrication method of the crystal device 2 is the same as that shown in FIG. 3 , except that the mask patterns are changed to the mask patterns 41 b and 42 b , and therefore, the description of the method will not be repeated here.
- FIG. 9 is a diagram showing the shape of the crystal plate 12 used in the tuning-fork type crystal device 2 according to the present invention and the shapes of the mask layer patterns for comparison.
- the crystal plate 12 can be fabricated that has two major faces that differ in the bend angle of the crotch portion.
- the unetched portion 112 left on the thus formed crystal plate 12 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of the unetched portion 112 is different from that of the prior art which has a ridge line extending obliquely between the two major faces.
- the size of the unetched portion 112 can be reduced (to about four-ninths in terms of volume ratio) compared with the prior art (in which the same mask pattern 41 b is used for both the major faces).
- the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy.
- FIG. 10 is a diagram showing a combination of mask patterns for a further alternative crystal device 3 according to the present invention.
- the tuning-fork type crystal device 3 is fabricating using mask patterns 41 c and 42 c that differ in the number of curved sections (R 1 , R 2 , R 3 ) forming the crotch portion, as shown in FIGS. 10A and 10B .
- the fabrication method of the crystal device 3 is the same as that shown in FIG. 3 , except that the mask patterns are changed to the mask patterns 41 c and 42 c , and therefore the description of the method will not be repeated here.
- FIG. 11 is a diagram showing the shape of the crystal plate 13 used in the tuning-fork type crystal device 3 according to the present invention and the shapes of the mask layer patterns for comparison.
- the tuning-fork type crystal device 3 can be fabricated that has two major faces that differ in the number of curved sections forming the crotch portion.
- the unetched portion 113 left on the thus formed crystal plate 13 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of the unetched portion 113 is different from that of the prior art which has a ridge line extending obliquely between the two major faces.
- the size of the unetched portion 113 can be reduced (to about one quarter in terms of volume ratio) compared with the prior art (in which the same mask pattern 41 c is used for both the major faces).
- the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy.
- the number of curved sections forming the crotch portion is represented by the number of center points of the curved sections, and that a continuous curve having, for example, two center points is regarded as containing two curved sections.
- FIG. 12 is a diagram showing a combination of mask patterns for a still further alternative crystal device 4 according to the present invention.
- the tuning-fork type crystal device 4 is fabricating using mask patterns 41 d and 42 d that differ in the curvature of the curve (R 1 , R 2 ) forming the crotch portion, as shown in FIGS. 12A and 12B .
- the fabrication method of the crystal device 4 is the same as that shown in FIG. 3 , except that the mask patterns are changed to the mask patterns 41 d and 42 d , and therefore the description of the method will not be repeated here.
- FIG. 13 is a diagram showing the shape of the crystal plate 14 used in the tuning-fork type crystal device 4 according to the present invention and the shapes of the mask layer patterns for comparison.
- the tuning-fork type crystal device 4 can be fabricated that has two major faces that differ in the curvature of the curve forming the crotch portion.
- the unetched portion 114 left on the thus formed crystal plate 14 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of the unetched portion 114 is different from that of the prior art which has a ridge line extending obliquely between the two major faces.
- the size of the unetched portion 114 can be reduced (to about four-ninths in terms of volume ratio) compared with the prior art (in which the same mask pattern 41 d is used for both the major faces).
- the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy.
- the crystal devices 1 to 4 having high reliability and high accuracy can be achieved.
- the crystal devices 1 to 4 are used for products such as crystal resonators and crystal oscillators, high reliability and accuracy can be obtained.
- the angular velocity can be detected accurately, and crystal gyros can be obtained that have high detection sensitivity and high accuracy.
- the unetched portion can be formed in the shape of a protrusion having a ridge line substantially parallel to the two major faces. Accordingly, in the crystal devices 1 to 4 , the processing step performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and productivity can thus be increased.
- the present invention is not limited to the combinations of differently shaped mask patterns used for the fabrication of the crystal devices 1 to 4 described above.
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Abstract
Description
- The present invention relates to a crystal device comprising a base and a plurality of vibrating prongs protruding from the base, and a fabrication method for the same; more particularly, the invention relates to a tuning-fork type crystal gyro to be used as an angular velocity sensor, and a fabrication method for the same.
- With the widespread use of compact and high-accuracy products such as HDDs (Hard Disk Drives), mobile computers, portable telephones, car telephones, and other mobile communication apparatus in recent years, there has developed an increasing need to further enhance the reliability and accuracy of crystal devices, typically crystal oscillators, used in these products.
- The need for increased reliability and increased accuracy has been growing, among others, for crystal gyros used for angular velocity detection in navigation systems or for camera shake control in video cameras.
-
FIG. 14 is a diagram showing the structure of a prior art tuning-fork type crystal device. - The structure of the prior art tuning-fork type crystal device will be described below (for example, refer to Patent Document 1). The prior art tuning-fork
type crystal device 2 comprises: a tuning-fork-shaped crystal plate 11 having abase 2 a formed from a crystal and vibratingprongs 2 b protruding the base; andelectrodes crystal plate 11. InFIG. 14 , thevibrating prongs 2 b each refer to the portion from the tip to the first bend of the fork just before thebase 2 a thereof, and thebase 2 a refers to the portion beyond the bend. - A prescribed electric field can be produced across the
crystal plate 11 by applying different potentials to therespective electrodes crystal plate 11 is a piezoelectric material, when an electric field is applied across the plate the plate contracts or expands according to the direction of the electric field. As a result, the vibrating prongs 2 b of thecrystal plate 11 vibrate, and the structure can thus be used as acrystal oscillator 2. - Next, a fabrication method for the prior art tuning-fork type crystal device will be described.
-
FIG. 16 is a diagram showing part of the fabrication process of the prior art tuning-fork type crystal device. First, as shown inFIG. 16A , acrystal substrate 15 is prepared by formingmask layers layers resist layers crystal substrate 15 are exposed to UV radiation of prescribed wavelength throughmasks 41 of thesame mask pattern 41 a. Theresist layers mask pattern 41 a is not formed. - Next, the
resist layers FIG. 16B , formingresist layer patterns resist layer patterns mask pattern 41 a of themask 41. - Further, by using the
resist layer patterns mask layers FIG. 16C , formingmask layer patterns mask layer patterns mask pattern 41 a of themask 41. - Next, the
resist layer patterns FIG. 16D . - Thereafter, the
crystal substrate 15 is etched as shown inFIG. 16E , thus producing the outer shape of thecrystal plate 11. -
FIG. 17 is a diagram showing the shape of the crystal plate formed by the prior art etching and the shapes of the mask layer patterns for comparison. - As shown in
FIG. 17 , themajor faces crystal plate 11 formed by the etching inFIG. 16E , which were the plane surfaces of thecrystal substrate 15, are formed in substantially the same shapes as the respectivemask layer patterns mask layers mask pattern 41 a, it follows that the twomajor faces crystal plate 11 are both formed in substantially the same shape. - After the etching in
FIG. 16E , themask layer patterns electrodes type crystal device 2 shown inFIG. 14 . - The structure and the fabrication method of the tuning-fork type crystal device according to the prior art described above are used for crystal resonators, crystal oscillators, crystal gyros, and various other applications.
- In the prior art tuning-fork type crystal device, it is common practice to form the
crystal plate 11 by etching. However, since the crystal has the property that its reaction rate differs depending on the direction it is etched (this property is generally called the anisotropic etching property), a ridge-likeunetched portion 111 projecting from a side face is necessarily formed, as shown inFIG. 14 , in an intermediate region of thebase 2 a connecting between thevibrating prongs 2 b, that is, inFIG. 14 , the portion that originates from the tip of one vibratingprong 2 b, passes through the root of the one vibratingprong 2 b and through the root of the other vibratingprong 2 b, and leads to the tip of that other vibratingprong 2 b (this portion is generally referred to as the crotch portion). - When the
unetched portion 111 is formed, as shown inFIG. 14 , thevibrating prong 2 b which should normally vibrate in the X-axis direction vibrates in a direction slightly tilted toward the Z-axis direction as indicated by W1. The vibration W1 produced by tilting toward the Z-axis direction tends to tilt greater toward the Z-axis direction as theunetched portion 111 becomes larger. -
FIG. 15 is a diagram showing an enlarged view and a side view of the crotch portion of the tuning fork and its adjacent regions in the prior art tuning-fork type crystal device. Here,FIG. 15 (b) shows the shape of the side face as viewed from the direction C inFIG. 15 (a). As shown inFIG. 15 (b), theunetched portion 111 is formed on the side face of thecrystal plate 11 in the shape of a ridge extending obliquely from onemajor face 211 to the othermajor face 221 of thecrystal plate 11. This produces the same effect as if a prop were placed obliquely across the root portion of the vibratingprong 2 b and, with this effect, the direction of vibration is tilted toward the Z-axis direction, producing the vibration W1. In this patent specification, the root refers to the portion at the boundary between the vibratingprong 2 b and thebase 2 a; inFIG. 15 (a), the bend corresponds to the root. - Further, as shown in
FIG. 15 (a), theunetched portion 111 left after the etching is formed only on one vibrating prong side of the crotch portion of the tuning fork, and as a result, the left and right vibratingprongs 2 b vibrate in different directions, as shown inFIG. 14 . - When the direction of vibration of any one vibrating
prong 2 b is unstable as described above, the resulting crystal device is often unstable and inaccurate in operation; in the prior art, therefore, the balance between the directions of vibration has been adjusted after forming thecrystal plate 11, by performing an additional processing step for appropriately removing portions of theelectrodes crystal plate 11. - One proposal has been made in
Patent Document 1 to stabilize the vibration of the crystal device. The proposal made inPatent document 1 aims to stabilize the vibration of the crystal device by optimizing the plan shape of thecrystal plate 11 according toPatent Document 1, it is stated that the plan shape of one major face 201 is the same as the plan shape of the othermajor face 211. - However, according to experiments conducted by the present inventors, it has been confirmed that, as long as the plan shape of one major face 201 of the
crystal plate 11 is the same as the plan shape of the othermajor face 211, no appreciable change occurs in the shape of theunetched portion 111 and, in most cases, theunetched portion 111 which causes the unstable vibration is formed in substantially the same shape, though its size may vary somewhat. That is, to whatever shape themask pattern 41 a of themask 41 alone is optimized that determines the plan shape of the crotch portion of the tuning fork, as shown inPatent Document 1, theunetched portion 111 which causes the unstable vibration is necessarily formed as long as themask pattern 41 a of the same shape is used for both themajor faces 201 and 211. - In the case of a crystal gyro as one application example of the tuning-fork type crystal device, the vibration tilted toward the Z axis such as the vibration W1 shown in
FIG. 14 becomes a very serious problem. The reason is that, in the crystal gyro, the Z-axis direction is nothing but the direction of the angular velocity to be detected, and any vibration in the Z-axis direction, such as the vibration W1, can affect the accurate detection of the angular velocity. As a result, the prior art crystal gyro has had the problem of low accuracy and low reliability. - Patent Document 1: Japanese Unexamined Patent Publication No. H10-41772 (
page 2, FIGS. 2 and 3) - It is an object of the present invention to provide a crystal device and a method for manufacturing the same that can overcome the prior art problem.
- It is another object of the present invention to provide a high-accuracy and high-reliability crystal device and a method for manufacturing the same.
- It is a further object of the present invention to provide a high-accuracy and high-reliability crystal gyro that can accurately detect angular velocity by using the crystal device of the invention in the crystal gyro, and a method for manufacturing such a crystal gyro.
- A crystal device according to the present invention has a crystal plate that includes a base and a plurality of vibrating prongs protruding from the base, wherein two major faces, each containing the base and the plurality of vibrating prongs, are formed on the crystal plate, and wherein the two major faces have respectively different outer shapes.
- A crystal device according to the present invention has a first major face, which contains a portion of the base and a portion of the vibrating prong within a single plane, and a second major face, which contains another portion of the base and another portion of the vibrating prong within a single plane, are formed on the crystal plate, wherein the first major face and the second major face have different outer shapes.
- Preferably, in the crystal device according to the present invention, the crystal plate includes at least a first vibrating prong and a second vibrating prong. Further preferably, the first and second major faces each have a crotch portion defined by a line that originates from the tip of the first vibrating prong, passes through the root of the first vibrating prong and through the root of the second vibrating prong, and leads to the tip of the second vibrating prong, wherein the crotch portion of the first major face and the crotch portion of the second major face have different shapes.
- Preferably, in the crystal device according to the present invention, the number of bends contained in the crotch portion of the first major face is different from the number of bends contained in the crotch portion of the second major face.
- Preferably, in the crystal device according to the present invention, the angle of a bend contained in the crotch portion of the first major face is different from the angle of a bend contained in the crotch portion of the second major face.
- Preferably, in the crystal device according to the present invention, the number of center points representing curved sections contained in the crotch portion of the first major face is different from the number of center points representing curved sections contained in the crotch portion of the second major face.
- Preferably, in the crystal device according to the present invention, the curvature of a curved section contained in the crotch portion of the first major face is different from the curvature of a curved section contained in the crotch portion of the second major face.
- A method for manufacturing a crystal device according to the present invention, the crystal device having a crystal plate that includes a base and a plurality of vibrating prongs protruding from the base, includes the steps of forming a resist layer made of a photosensitive material and a mask layer having corrosion resistance to etching of a crystal on each of two plane surfaces of a crystal substrate, exposing the resist layer formed on one plane surface of the crystal substrate to radiation through a first mask on which a first mask pattern of a prescribed shape is drawn and exposing the resist layer formed on the other plane surface of the crystal substrate to radiation through a second mask on which a second mask pattern is drawn that differs in shape from the first mask pattern, forming a first resist layer pattern by patterning the resist layer on the one plane surface of the crystal substrate into a shape corresponding to the first mask pattern, and forming a second resist layer pattern by patterning the resist layer on the other plane surface of the crystal substrate into a shape corresponding to the second mask pattern, forming a first mask layer pattern by patterning the mask layer on the one plane surface of the crystal substrate into the shape corresponding to the first mask pattern, and forming a second mask layer pattern by patterning the mask layer on the other plane surface of the crystal substrate into the shape corresponding to the second mask pattern, and forming the crystal plate in a desired shape by etching the crystal substrate using the first mask pattern and the second mask pattern as masks.
- The method according to the present invention includes the steps of forming a resist layer made of a photosensitive material and a mask layer having corrosion resistance on each of two plane surfaces of a crystal substrate, exposing the resist layer formed on the first plane surface of the crystal substrate to radiation through a first mask on which a first mask pattern is drawn and exposing the resist layer formed on the second plane surface of the crystal substrate to radiation through a second mask on which a second mask pattern is drawn that differs in shape from the first mask pattern, forming a first resist layer pattern by patterning the resist layer on the first plane surface of the crystal substrate into a shape corresponding to the first mask pattern and forming a second resist layer pattern by patterning the resist layer on the second plane surface of the crystal substrate into a shape corresponding to the second mask pattern, forming a first mask layer pattern by patterning the mask layer on the first plane surface of the crystal substrate into a shape corresponding to the first mask pattern and forming a second mask layer pattern by patterning the mask layer on the second plane surface of the crystal substrate into a shape corresponding to the second mask pattern, and forming the crystal plate by etching the crystal substrate through the first mask layer pattern and the second mask layer pattern.
- Preferably in the method according to the present invention, the first mask layer pattern has an outer shape that contains a portion of the base and a portion of the vibrating prong within a single plane, and the second mask layer pattern has an outer shape that contains another portion of the base and another portion of the vibrating prong within a single plane.
- Preferably, in the method according to the present invention, the crystal plate includes at least a first vibrating prong and a second vibrating prong.
- Preferably, in the method according to the present invention, the first and second mask layer patterns each have a crotch portion defined by a line that originates from the tip of the first vibrating prong, passes through the root of the first vibrating prong and through the root of the second vibrating prong, and leads to the tip of the second vibrating prong.
- Preferably, in the method according to the present invention, the crotch portion of the first mask layer pattern and the crotch portion of the second mask layer pattern have different shapes.
- Preferably, in the method according to the present invention, the number of bends contained in the crotch portion of the first mask layer pattern is different from the number of bends contained in the crotch portion of the second mask layer pattern.
- Preferably, in the method according to the present invention, the angle of a bend contained in the crotch portion of the first mask layer pattern is different from the angle of a bend contained in the crotch portion of the second mask layer pattern.
- Preferably, in the method according to the present invention, the number of center points representing curved sections contained in the crotch portion of the first mask layer pattern is different from the number of center points representing curved sections contained in the crotch portion of the second mask layer pattern.
- Preferably, in the method according to the present invention, the curvature of a curved section contained in the crotch portion of the first mask layer pattern is different from the curvature of a curved section contained in the crotch portion of the second mask layer pattern.
- One feature of the crystal device according to the present invention is that the two major faces of the crystal plate have different outer shapes, in particular, the crotch portions of the respective major faces have different shapes.
- According to the crystal device of the present invention, the vibration of the (tuning-fork type) crystal plate can be stabilized, and as a result, a crystal device having high reliability and high accuracy can be achieved.
- Further, according to the crystal device of the present invention, the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity of the crystal device can be increased compared with the prior art.
- Furthermore, when the crystal device of the present invention is used for a crystal gyro, the vibration can be stabilized, and therefore, the angular velocity can be detected accurately; as a result, a crystal gyro can be obtained that have high detection sensitivity and high accuracy.
- According to the crystal device manufacturing method of the present invention, a crystal device having stable vibration characteristics can be formed, and as a result, a crystal device having high reliability and high accuracy can be produced.
- Furthermore, according to the crystal device manufacturing method of the present invention, the processing step that has had to be performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and as a result, productivity can be increased.
-
FIG. 1 is a diagram showing the structure of acrystal device 1 according to the present invention. -
FIG. 2 is a diagram showing an enlarged view and a side view of a crotch portion and its adjacent regions in thecrystal device 1 according to the present invention. -
FIG. 3 is a diagram showing the first half of the manufacturing process of thecrystal device 1 according to the present invention. -
FIG. 4 is a diagram showing the second half of the manufacturing process of thecrystal device 1 according to the present invention. -
FIG. 5 is a diagram showing the shape of acrystal plate 10 and the shapes of mask layer patterns in thecrystal device 1 according to the present invention. -
FIG. 6 is a diagram showing the etching characteristic of a crystal substrate formed from a conventional synthetic crystal. -
FIG. 7 is a diagram showing mask patterns used in the manufacturing process of thecrystal device 1 according to the present invention. -
FIG. 8 is a diagram showing mask patterns used in the manufacturing method for analternative crystal device 2 according to the present invention. -
FIG. 9 is a diagram showing the shape of acrystal plate 12 and the shapes of mask layer patterns in thealternative crystal device 2 according to the present invention. -
FIG. 10 is a diagram showing mask patterns used in the fabrication method for a furtheralternative crystal device 3 according to the present invention. -
FIG. 11 is a diagram showing the shape of acrystal plate 13 and the shapes of mask layer patterns in the furtheralternative crystal device 3 according to the present invention. -
FIG. 12 is a diagram showing mask patterns used in the manufacturing method for a still furtheralternative crystal device 4 according to the present invention. -
FIG. 13 is a diagram showing the shape of acrystal plate 14 and the shapes of mask layer patterns in the still furtheralternative crystal device 4 according to the present invention. -
FIG. 14 is a diagram showing the structure of a prior art tuning-fork type crystal device. -
FIG. 15 is a diagram showing an enlarged view and a side view of the crotch portion of a tuning fork and its adjacent regions in the prior art tuning-fork type crystal device. -
FIG. 16 is a diagram showing part of the manufacturing process of the prior art tuning-fork type crystal device. -
FIG. 17 is a diagram showing the shape of the crystal plate formed by etching according to the prior art and the shapes of mask layer patterns for comparison. -
FIG. 1 is a diagram showing the structure of acrystal device 1 according to the present invention. - The
crystal device 1 according to the present invention comprises acrystal plate 10 formed from a crystal, andelectrodes crystal plate 10 is formed in the shape of a tuning fork which is made up of abase 1 a and a plurality of vibratingprongs 1 b protruding from thebase 1 a. Theelectrodes crystal plate 10 by applying different potentials to the respective electrodes. Since thecrystal plate 10 is a piezoelectric material, the plate contracts or expands according to the direction of the applied electric field; this contracting/expanding motion causes the vibratingprongs 1 b to vibrate. When a voltage is applied between theelectrodes crystal device 1, the two vibratingprongs 1 b produce vibrations W0 along the X-axis direction. - In this patent specification, the portion defined by an outline extending from the tip to the first bend in the direction of the base will hereinafter be referred to as the “vibrating prong”, the portion beyond the bend will be referred to as the “base”, and the portion at the boundary between the base and the vibrating prong will be referred to as the “root”.
- The difference between the
crystal device 1 of the present invention shown inFIG. 1 and the tuning-fork type crystal device of the prior art lies in the outer shape of thecrystal plate 10, especially in the shapes of the twomajor faces base 1 a and vibratingprongs 1 b of thecrystal plate 10. In the embodiment of the present invention, the shape of themajor face 210 is different from the shape of themajor face 220, especially in the intermediate region connecting between the two vibrating prongs (that is, inFIG. 1 , the portion that originates from the tip of one vibratingprong 1 b, passes through the root of the one vibratingprong 1 b and through the root of the other vibratingprong 1 b, and leads to the tip of that other vibratingprong 1 b (this portion is hereinafter referred to as the “crotch portion”)). This constitutes one of the most important features of the present invention. - That is, while the shape of the crotch portion of the
major face 210 contains three bends, the shape of the crotch portion of themajor face 220 contains two bends (one of the two bends of themajor face 220 is hidden from view inFIG. 1 ). In any prior art tuning-fork type crystal device, the twomajor faces - When the crotch portions of the two
major faces crystal plate 10 are formed in different shapes, the collateral effect is that the shape of the crystal plate (the shape of theunetched portion 110 formed on a side face of the crotch portion of the crystal plate 10) can be made different from that of the prior art. In the crystal device according to the present embodiment, stable vibration characteristics such as the vibrations W0 along the X axis shown inFIG. 1 can be obtained by forming theunetched portion 110 in an optimum shape. -
FIG. 2A is an enlarged view of the crotch portion and its adjacent regions in the tuning-forktype crystal device 1 shown inFIG. 1 , andFIG. 2B is a diagram showing the shape of the side face as viewed from the direction B inFIG. 2A . - As shown in
FIGS. 2A and 2B , theunetched portion 110 of thecrystal device 1, which is left on the side face of the crotch portion of thecrystal plate 10, is formed as a ridge-like protrusion having a ridge line substantially parallel to the twomajor faces unetched portion 110 of thecrystal device 1 is different from that of the prior art which has a ridge line extending obliquely between the two major faces. Furthermore, the size of theunetched portion 110 can be reduced (to about one quarter in terms of volume ratio) compared with the prior art (in which thesame mask pattern 21 b is used for both the major faces). - As described above, according to the present invention, the
unetched portion 110 formed on the side face of the crotch portion of thecrystal plate 10 can be made very small and can be formed in the shape of a protrusion having a ridge line substantially parallel to the twomajor faces - A manufacturing method for the
crystal device 1 will be described below. -
FIG. 3 is a diagram showing the first half of the manufacturing process of thecrystal device 1,FIG. 4 is a diagram showing the second half of the manufacturing process of thecrystal device 1, andFIG. 7 is a diagram showing mask patterns used in the manufacturing process of thecrystal device 1. - First, as shown in
FIG. 3A , acrystal substrate 15 is prepared by forming mask layers 21 and 22 and resistlayers crystal substrate 15 used in the present embodiment is a substrate generally called a Z plate whose plane faces are substantially perpendicular to the crystallographic z-axis direction of the crystal (the plane faces make an angle of 85 to 95 degrees with respect to the Z axis). - Further, in the present embodiment, the mask layers 21 and 22 are each formed from a composite layer consisting of a chromium (Cr) film deposited to a thickness of 0.05 μm on the
crystal substrate 15 and a gold (Au) film deposited to a thickness of 0.15 μm on the Cr film. The resist layers 31 and 32 are formed using a positive resist OFPR-800 manufactured by Tokyo Ohka Kogyo Co., Ltd. - One plane surface of the
crystal substrate 15 on which themask layer 21 and the resistlayer 31 are formed and the other plane surface on which themask layer 22 and the resistlayer 32 are formed are exposed to UV radiation of prescribed wavelength throughmasks - In the present embodiment, the
mask pattern 41 a drawn on themask 41 and themask pattern 42 a drawn on themask 42 are different in shape. Themask pattern 41 a drawn on themask 41 has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, as shown inFIG. 7A . In themask pattern 41 a, the intermediate region (i.e., the crotch portion) connecting between the two vibrating prongs has a shape that contains three bends formed by bending a straight line. On the other hand, themask pattern 42 a formed on themask 42 has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, as shown inFIG. 7B . In themask pattern 42 a, the intermediate region (i.e., the crotch portion) connecting between the two vibrating prongs has a shape that contains two bends formed by bending a straight line. In this way, the shape of the crotch portion differs between themask pattern 41 a of themask 41 and themask pattern 42 a of themask 42; in particular, the number of bends contained in the crotch portion differs between them. - Next, the resist
layers FIG. 3B , forming resistlayer patterns - Here, the resist
layer pattern 31 a is formed in the same shape as themask pattern 41 a of themask 41, while the resistlayer pattern 32 a is formed in the same shape as themask pattern 42 a of themask 42. That is, the resistlayer pattern 31 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in the resistlayer pattern 31 a has a shape that contains three bends. On the other hand, the resistlayer pattern 32 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in the resistlayer pattern 32 a has a shape that contains two bends. - Next, using the resist
layer patterns FIG. 3C , formingmask layer patterns mask layer patterns - Here, the
mask layer pattern 21 a, like the resistlayer pattern 31 a, is formed in the same shape as themask pattern 41 a of themask 41, while themask layer pattern 22 a, like the resistlayer pattern 32 a, is formed in the same shape as themask pattern 42 a of themask 42. That is, themask layer pattern 21 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in themask layer pattern 21 a has a shape that contains three bends. On the other hand, themask layer pattern 22 a has an outer shape defining the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs in themask layer pattern 22 a has a shape that contains two bends. - Next, by removing the resist
layer patterns FIG. 3D , themask layer patterns crystal substrate 15. In the present embodiment, OFPR-800 used for forming the resistlayer patterns -
FIG. 4A is a diagram showing themask layer patterns crystal substrate 15. The A-A cross section ofFIG. 4A is shown inFIG. 3D . By etching thecrystal substrate 15 shown inFIG. 4A , thecrystal plate 10 whose outer shape is defined by the mask layers 21 a and 22 a, and whose one major face is differently shaped than its other major face, is completed as shown inFIG. 4B . -
FIG. 5 is a diagram showing the shape of thecrystal plate 10 used in thecrystal device 1 according to the present invention and the shapes of the mask layer patterns for comparison. - In the present embodiment, one
major face 210 of thecrystal plate 10 is formed in substantially the same shape as themask layer pattern 21 a, and has an outer shape defined by the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs has a shape that contains three bends. On the other hand, the othermajor face 220 of thecrystal plate 10 is formed in substantially the same shape as themask layer pattern 22 a, and has an outer shape defined by the plan shape of the base and the plan shapes of the two vibrating prongs, and the crotch portion connecting between the two vibrating prongs has a shape that contains two bends. Accordingly, in the present embodiment, the shape of the onemajor face 210 of thecrystal plate 10 is different from that of the othermajor face 220. - The
crystal plate 10 formed by etching inFIG. 4B has anunetched portion 110 left unetched on the side face of the crotch portion connecting between the two vibrating prongs. This is due to the etching characteristic peculiar to the crystal. The crystal has the characteristic that its etch rate varies with its crystal orientation; this characteristic is generally known as the anisotropic etching characteristic. A protrusion such as theunetched portion 110 is necessarily formed on the side face of the crotch portion of thecrystal plate 10 because of the effect of the anisotropic etching characteristic of the crystal. - In the present embodiment, however, the size of the
unetched portion 110 can be greatly reduced compared with the prior art, because the shapes of themask layer patterns unetched portion 110 can be formed in a different shape than that of the prior art, that is, in the shape of a ridge-like protrusion having a ridge line substantially parallel to the twomajor faces mask layer patterns - In this way, the shapes of the
mask layer patterns - Through many experiments conducted by the present inventors, several combinations have been obtained for the optimum shapes of the
mask layer patterns mask layer patterns - Finally, the
mask layer patterns electrodes FIG. 1 . - It has also been verified that the tuning-fork
type crystal device 1 according to the present invention can be very effectively used for crystal gyros. In crystal gyros that utilize Coriolis forces, the Z-axis direction (the direction parallel to the Z axis which is one of the crystallographic axes of the crystal) is perpendicular to the vibration direction of the vibrating prongs, and is nothing but the direction of the angular velocity to be detected. In the tuning-forktype crystal device 1, as can be seen in the vibrations W0, hardly any vibrations occur in the Z-axis direction, so that only the component of the angular velocity to be detected can be accurately detected. As a result, when the tuning-forktype crystal device 1 according to the present invention is used, a crystal gyro can be achieved that has very good detection sensitivity and high reliability compared with the prior art. - Usually, in crystal gyros, the direction of the angular velocity to be detected is perpendicular to the vibration direction of the vibrating prongs, and the angular velocity cannot be detected accurately unless the vibration direction is stable as designed. With the crystal gyro using the crystal device of the present invention, on the other hand, the angular velocity perpendicular to the vibration direction can be accurately detected, because the vibration direction is stable as designed.
- Next, a description will be given of the unetched portion.
- As earlier described, in the
crystal device 1 of the present invention, since the outer shapes of the two major faces of the crystal plate are made different from each other, the unetched portion remaining on the side face of the crotch portion of the crystal plate can be made very small. Furthermore, the unetched portion can be formed in the shape of a protrusion having a ridge line substantially parallel to the two major faces. Moreover, the unetched portion can be formed parallel to the major faces of the crystal plate in such a manner as to be substantially centralized on the side face of the crotch portion. In this way, the unetched portion whose shape is significantly different from that of the prior art constitutes a feature of the present invention. - In the crystal plate used for the prior art crystal device, the
unetched portion 111 was formed in a ridge-like shape on the side face of the crotch portion in such a manner as to extend across the side face of the crystal plate obliquely from one major face to the other major face (seeFIG. 15B ). This produced the same effect as if a prop had been placed obliquely across the root portion of the vibrating prong, causing the vibrating prong to vibrate in a direction tilted toward the Z-axis direction. - On the other hand, in the
crystal device 1 of the present invention, since theunetched portion 110 is small in size, and is formed parallel to the major faces of the crystal plate in such a manner as to be substantially centralized on the side face of the crotch portion, as described above, the root portion of the vibrating prong is not physically strained, and the desired stable vibrations can be produced. - The
unetched portion 110 is formed when the crystal substrate is etched. The shape of theunetched portion 110 is substantially determined by the shapes of the mask layer patterns formed in the step that precedes the etching step. The shape of theunetched portion 110 in thecrystal device 1 of the present invention is achieved by making the shape of the mask layer pattern different between the upper and lower surfaces of the crystal substrate. This utilizes the etching characteristic that the etch rate differs between the upper and lower surfaces of the crystal substrate. -
FIG. 6 is a diagram showing the etching characteristic of the crystal substrate formed from a conventional synthetic crystal. - The crystal substrates 15 shown in
FIGS. 6A and 6B are each a substrate cut so as to have plane faces substantially perpendicular to the crystallographic z axis (the thus cut substrate is generally called a “Z plate”). However, the growth direction “g” of the crystal in the crystal substrate ofFIG. 6A is opposite to the growth direction “g” of the crystal in the crystal substrate ofFIG. 6B . That is,FIGS. 6A and 6B represent the relationship between the front and back of the crystal substrate. - Usually, in the crystal substrate 15 (Z plate) cut so as to have plane faces perpendicular to the z axis as shown in
FIG. 6A or 6B, there are three Y axes (Y1-1 to Y1-3 or Y2-1 to Y2-3) spaced 120 degrees apart from each other on each plane face. - If
such crystal substrates 15 are etched using the same conditions, the etch rates e1 in directions parallel to the Y axes and the etch rate e2 in directions normal to the Y axes are different between the case ofFIG. 6A and the case ofFIG. 6B . - Generally, in the plane face toward which the growth proceeds in the direction “g” as shown in
FIG. 6A , the etch rate e1 in the direction parallel to the Y axis (Y1-1) and the etch rate e2 in the direction normal to the Y axis (Y1-2) have the relationship defined by e1>e2. On the other hand, in the plane face from which the growth proceeds in the direction “g” as shown inFIG. 6B , the etch rate e1 in the direction parallel to the Y axis (Y2-1) and the etch rate e2 in the direction normal to the Y axis (Y2-2) have the relationship defined by e1<e2. - If the shapes of the mask layer patterns are designed by considering these etch rates e1 and e2, it becomes possible to form the crystal plate having the unetched portion as depicted in the present invention.
- For example, suppose that the
upper face 210 of thecrystal plate 10 shown inFIG. 5 is formed as shown inFIG. 6A , and that the three Y axes (Y1-1 to Y1-3) inFIG. 6A are arranged as shown inFIG. 5 . In this case, the direction e2 at right angles to the Y1-2 axis substantially coincides with the projecting direction of theunetched portion 110. Since the etching is difficult to proceed in the direction e2, the unetched portion is formed in the direction e2. -
FIG. 8 is a diagram showing a combination of mask patterns for analternative crystal device 2 according to the present invention. - In the case of the
alternative crystal device 2 according to the present invention, the tuning-forktype crystal device 2 is fabricated by usingmask patterns FIGS. 8A and 8B . The fabrication method of thecrystal device 2 is the same as that shown inFIG. 3 , except that the mask patterns are changed to themask patterns -
FIG. 9 is a diagram showing the shape of thecrystal plate 12 used in the tuning-forktype crystal device 2 according to the present invention and the shapes of the mask layer patterns for comparison. - By using the
mask patterns crystal plate 12 can be fabricated that has two major faces that differ in the bend angle of the crotch portion. Theunetched portion 112 left on the thus formedcrystal plate 12 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of theunetched portion 112 is different from that of the prior art which has a ridge line extending obliquely between the two major faces. Furthermore, the size of theunetched portion 112 can be reduced (to about four-ninths in terms of volume ratio) compared with the prior art (in which thesame mask pattern 41 b is used for both the major faces). - As a result, in the present embodiment also, there is no straining prop in the root portion of the vibrating prong, and the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy.
-
FIG. 10 is a diagram showing a combination of mask patterns for a furtheralternative crystal device 3 according to the present invention. - In the further
alternative crystal device 3 according to the present invention, the tuning-forktype crystal device 3 is fabricating usingmask patterns 41 c and 42 c that differ in the number of curved sections (R1, R2, R3) forming the crotch portion, as shown inFIGS. 10A and 10B . The fabrication method of thecrystal device 3 is the same as that shown inFIG. 3 , except that the mask patterns are changed to themask patterns 41 c and 42 c, and therefore the description of the method will not be repeated here. -
FIG. 11 is a diagram showing the shape of thecrystal plate 13 used in the tuning-forktype crystal device 3 according to the present invention and the shapes of the mask layer patterns for comparison. - By using the
mask patterns 41 c and 42 c that differ in the number of curved sections forming the crotch portion, the tuning-forktype crystal device 3 can be fabricated that has two major faces that differ in the number of curved sections forming the crotch portion. Theunetched portion 113 left on the thus formedcrystal plate 13 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of theunetched portion 113 is different from that of the prior art which has a ridge line extending obliquely between the two major faces. Furthermore, the size of theunetched portion 113 can be reduced (to about one quarter in terms of volume ratio) compared with the prior art (in which the same mask pattern 41 c is used for both the major faces). - As a result, in the present embodiment also, there is no straining prop in the root portion of the vibrating prong, and the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy. Here, in the present invention, it is to be understood that the number of curved sections forming the crotch portion is represented by the number of center points of the curved sections, and that a continuous curve having, for example, two center points is regarded as containing two curved sections.
-
FIG. 12 is a diagram showing a combination of mask patterns for a still furtheralternative crystal device 4 according to the present invention. - In the still further
alternative crystal device 4 according to the present invention, the tuning-forktype crystal device 4 is fabricating usingmask patterns 41 d and 42 d that differ in the curvature of the curve (R1, R2) forming the crotch portion, as shown inFIGS. 12A and 12B . The fabrication method of thecrystal device 4 is the same as that shown inFIG. 3 , except that the mask patterns are changed to themask patterns 41 d and 42 d, and therefore the description of the method will not be repeated here. -
FIG. 13 is a diagram showing the shape of thecrystal plate 14 used in the tuning-forktype crystal device 4 according to the present invention and the shapes of the mask layer patterns for comparison. - By using the
mask patterns 41 d and 42 d that differ in the curvature of the curve forming the crotch portion, the tuning-forktype crystal device 4 can be fabricated that has two major faces that differ in the curvature of the curve forming the crotch portion. The unetched portion 114 left on the thus formedcrystal plate 14 is shaped in the form of a protrusion having a ridge line substantially parallel to the two major faces. That is, the shape of the unetched portion 114 is different from that of the prior art which has a ridge line extending obliquely between the two major faces. Furthermore, the size of the unetched portion 114 can be reduced (to about four-ninths in terms of volume ratio) compared with the prior art (in which the same mask pattern 41 d is used for both the major faces). - As a result, in the present embodiment also, there is no straining prop in the root portion of the vibrating prong, and the vibrating prong can produce stable vibrations along the X axis as designed, thus achieving the crystal device having high reliability and high accuracy.
- As described above, according to the present invention, the
crystal devices 1 to 4 having high reliability and high accuracy can be achieved. Whensuch crystal devices 1 to 4 are used for products such as crystal resonators and crystal oscillators, high reliability and accuracy can be obtained. Furthermore, whensuch crystal devices 1 to 4 are used for crystal gyros, the angular velocity can be detected accurately, and crystal gyros can be obtained that have high detection sensitivity and high accuracy. - Further, in the
crystal devices 1 to 4 described above, not only can the size of the unetched portion be reduced compared with that of the prior art, but the unetched portion can be formed in the shape of a protrusion having a ridge line substantially parallel to the two major faces. Accordingly, in thecrystal devices 1 to 4, the processing step performed after the etching step in the prior art in order to achieve stable vibration characteristics can be simplified or omitted, and productivity can thus be increased. - It will be recognized that the present invention is not limited to the combinations of differently shaped mask patterns used for the fabrication of the
crystal devices 1 to 4 described above.
Claims (16)
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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JP2004181930 | 2004-06-21 | ||
JP2004-181930 | 2004-06-21 | ||
PCT/JP2005/010528 WO2005125006A1 (en) | 2004-06-21 | 2005-06-02 | Quartz device and quartz device manufacturing method |
Related Parent Applications (1)
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PCT/JP2005/010528 A-371-Of-International WO2005125006A1 (en) | 2004-06-21 | 2005-06-02 | Quartz device and quartz device manufacturing method |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US12/801,020 Division US8258676B2 (en) | 2004-06-21 | 2010-05-17 | Crystal device and method for manufacturing crystal device |
Publications (1)
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US20070247032A1 true US20070247032A1 (en) | 2007-10-25 |
Family
ID=35510059
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
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US11/630,154 Abandoned US20070247032A1 (en) | 2004-06-21 | 2005-06-02 | Crystal Device and Method for Manufacturing Crystal Device |
US12/801,020 Expired - Fee Related US8258676B2 (en) | 2004-06-21 | 2010-05-17 | Crystal device and method for manufacturing crystal device |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
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US12/801,020 Expired - Fee Related US8258676B2 (en) | 2004-06-21 | 2010-05-17 | Crystal device and method for manufacturing crystal device |
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US (2) | US20070247032A1 (en) |
JP (1) | JP4545744B2 (en) |
CN (1) | CN1973435B (en) |
WO (1) | WO2005125006A1 (en) |
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JP4935244B2 (en) * | 2006-08-29 | 2012-05-23 | 株式会社大真空 | Tuning fork type piezoelectric vibrating piece and tuning fork type piezoelectric vibrating device |
JP2014197728A (en) * | 2013-03-29 | 2014-10-16 | セイコーエプソン株式会社 | Process of manufacturing vibration piece |
JP6340774B2 (en) * | 2013-11-16 | 2018-06-13 | セイコーエプソン株式会社 | Vibration element, vibrator, oscillator, electronic device, and moving object |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5723790A (en) * | 1995-02-27 | 1998-03-03 | Andersson; Gert | Monocrystalline accelerometer and angular rate sensor and methods for making and using same |
US20030080652A1 (en) * | 2001-10-31 | 2003-05-01 | Hirofumi Kawashima | Quartz crystal unit and its manufacturing method |
US6949870B2 (en) * | 2003-11-10 | 2005-09-27 | Nihon Dempa Kogyo Co., Ltd. | Tuning fork-type crystal vibrator |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS52137991A (en) | 1976-05-14 | 1977-11-17 | Seiko Instr & Electronics Ltd | Tuning fork type crystal resonator |
JPS55125714A (en) * | 1979-03-22 | 1980-09-27 | Citizen Watch Co Ltd | Construction of tuning fork type crystal oscillator |
JPS57116408A (en) | 1981-01-13 | 1982-07-20 | Citizen Watch Co Ltd | Tuning-fork type quartz oscillator |
US4415827A (en) * | 1981-05-27 | 1983-11-15 | Statek Corporation | Microresonator of tuning fork configuration operating at its second overtone frequency |
JPS5983412A (en) * | 1982-11-04 | 1984-05-14 | Seiko Instr & Electronics Ltd | Tuning fork type crystal oscillator |
EP1788702A3 (en) * | 2000-12-25 | 2008-01-16 | Seiko Epson Corporation | Vibrating piece, vibrator, oscillator, and electronic equipment |
JP4106540B2 (en) * | 2002-08-08 | 2008-06-25 | セイコーエプソン株式会社 | Quartz Device, Quartz Vibrating Piece, Quartz Vibrating Piece Manufacturing Method, Cell Phone Device Using Quartz Device, and Electronic Equipment Using Quartz Device |
JP4509621B2 (en) * | 2003-10-10 | 2010-07-21 | 日本電波工業株式会社 | Manufacturing method of tuning-fork type crystal resonator for angular velocity sensor |
JP4502219B2 (en) * | 2006-10-10 | 2010-07-14 | 日本電波工業株式会社 | Manufacturing method of tuning fork type crystal resonator element |
-
2005
- 2005-06-02 US US11/630,154 patent/US20070247032A1/en not_active Abandoned
- 2005-06-02 WO PCT/JP2005/010528 patent/WO2005125006A1/en active Application Filing
- 2005-06-02 JP JP2006514707A patent/JP4545744B2/en not_active Expired - Fee Related
- 2005-06-02 CN CN2005800204830A patent/CN1973435B/en not_active Expired - Fee Related
-
2010
- 2010-05-17 US US12/801,020 patent/US8258676B2/en not_active Expired - Fee Related
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5723790A (en) * | 1995-02-27 | 1998-03-03 | Andersson; Gert | Monocrystalline accelerometer and angular rate sensor and methods for making and using same |
US20030080652A1 (en) * | 2001-10-31 | 2003-05-01 | Hirofumi Kawashima | Quartz crystal unit and its manufacturing method |
US6949870B2 (en) * | 2003-11-10 | 2005-09-27 | Nihon Dempa Kogyo Co., Ltd. | Tuning fork-type crystal vibrator |
Also Published As
Publication number | Publication date |
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CN1973435A (en) | 2007-05-30 |
US20100223769A1 (en) | 2010-09-09 |
CN1973435B (en) | 2010-06-23 |
JP4545744B2 (en) | 2010-09-15 |
JPWO2005125006A1 (en) | 2008-04-17 |
US8258676B2 (en) | 2012-09-04 |
WO2005125006A1 (en) | 2005-12-29 |
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