An efficiently produced vibratory gyroscope having secure connections is provided. The vibratory gyroscope comprises a vibrator in which driving electrodes, grounding electrodes, and land sections electrically connected to the driving and grounding electrodes are formed. A holding member holds the vibrator, allowing it to vibrate. The vibratory gyroscope also comprises wiring patterns, vibrator-side end sections, a substrate-side end section and a wiring section positioned between the vibrator-side end sections and the substrate-side end section. The vibrator-side end sections are connected to a flexible wiring board comprising land sections electrically connected to the wiring sections and also electrically connected to the land sections of the vibrator and to the substrate-connection end section formed in the circuit-substrate-side end section of the flexible wiring board. A circuit substrate is electrically connected to the wiring patterns.

BACKGROUND OF THE INVENTION
 1. Field of the Invention
 The present invention relates to a vibratory gyroscope to be used, for
 example, in angular rotation velocity sensors for vehicle navigation
 systems.
 2. Description of the Related Art
 A vibratory gyroscope utilizes a dynamic phenomenon in which Coriolis force
 is generated at right angles to the vibration direction when a vibrating
 object is provided with an angular rotation velocity. The vibratory
 gyroscope has electrodes formed on plural faces of a vibrator thereof and
 alternating current (AC) is applied from an external source to the
 electrodes to obtain a detection output resulting from piezoelectric
 effects and relies on fine lead wires for electrical connection to the
 vibrator.
 With the lead-wire connection, however, wires are apt to be cut in
 connection processing; therefore, wires must be connected one by one. In
 connection processing involving manual soldering, processing efficiency is
 significantly reduced.
 SUMMARY OF THE INVENTION
 In consideration of the above problems, objects of the present invention
 are to provide a vibratory gyroscope as follows:
 a vibratory gyroscope in which the connection strength can be made much
 higher than that of conventional vibratory gyroscopes and which allows the
 processing efficiency to be improved;
 a vibratory gyroscope in which vibration of a circuit substrate is not
 significantly transferred to the vibrator, and conversely, vibration of
 the vibrator is also not significantly transferred to the circuit
 substrate;
 a vibratory gyroscope in which the width of a wiring section is smaller to
 make it more difficult for vibration to be transferred between the circuit
 substrate and the vibrator;
 a vibratory gyroscope in which vibration of the vibrator is not
 significantly transferred to the circuit substrate;
 a vibratory gyroscope in which land sections are arranged on two opposite
 sides of the vibrator, but only a single flexible wiring board is
 sufficient;
 a vibratory gyroscope in which even when electrodes having identical
 potentials are formed on two opposite sides of the vibrator, the width of
 the wiring section is not allowed to be larger;
 a vibratory gyroscope in which vibration is well balanced;
 a vibratory gyroscope in which although plural wiring patterns and
 electrodes are formed, the connection processing can be achieved by a
 one-time operation for one side of the vibrator; and
 a vibratory gyroscope in which even when undesirable forces impinge on the
 land sections of the vibrator and wiring patterns, connections are not
 broken.
 To achieve these objects, according to the present invention, there is
 provided a vibratory gyroscope that comprises a vibrator having electrodes
 and land sections electrically connected to the electrodes formed therein;
 a holding member to hold the vibrator so as to vibrate; a flexible wiring
 board comprising a wiring section in which wiring patterns are formed and
 which comprises at least vibrator-side end sections and
 circuit-substrate-side end sections and is positioned between the
 vibrator-side end sections and the circuit-substrate-side end sections,
 the vibrator-side end sections comprising land sections electrically
 connected to the wiring patterns and electrically connected to the land
 sections; and a circuit substrate connected to the land sections arranged
 on the circuit-substrate-side end section of the flexible wiring board and
 electrically connected to the wiring patterns.
 In the above vibratory gyroscope, the wiring section of the flexible wiring
 board may be narrower than the vibrator-side end section and the
 circuit-substrate-side end section.
 Furthermore, according to the present invention, a plurality of land
 sections of the vibrator may be formed, the corresponding land sections in
 the flexible wiring board may be connected within the vibrator-side end
 section to the land sections of the vibrator which are at least arranged
 to be adjacent to each other and have the same potentials, and they may be
 formed in the wiring section with the wiring patterns, which are
 electrically connected to the land sections of the flexible wiring board,
 arranged so as to be common.
 Furthermore, according to the present invention, the vibrator may comprise
 vibration arms individually comprising a free end to vibrate in a state
 wherein one end is held, a base end section of the vibrator may be held by
 the holding member, the land sections of the vibrator-side end sections
 are arranged in the base end section of the vibrator, and the holding
 member is fixed with the circuit-substrate-side end section.
 Furthermore, in the vibratory gyroscope according to the present invention,
 the vibrator may be in a plate-like shape and may comprise driving or
 detection electrodes on front and back sides thereof and the land sections
 electrically connected to the driving or detection electrodes; the
 flexible wiring board may comprise a branch section in which the wiring
 section branches into two sections in a side of the vibrator rather than
 the center side, the vibrator-side end section for the front side of the
 vibrator, and the vibrator-side end section for the back side of the
 vibrator; and land sections arranged in each of the vibrator-side end
 sections may be connected to corresponding land sections formed on the
 front and back sides of the vibrator.
 In the above vibratory gyroscope, the wiring patterns individually
 connected to the land sections of the vibrator, which have the same
 potentials in the front and back sides of the vibrator, may be
 incorporated in the branch section and directed to the
 circuit-substrate-side end section.
 In this case, according to the present invention, the wiring section may
 originate centrally from the vibrator-side end section.
 Furthermore, in the above vibratory gyroscope, paste primarily comprising
 silver to form the electrodes and land sections of the vibrator, solders
 of solder paste or solder plating may be arranged in the land sections of
 the vibrator-side end sections of the flexible wiring board, and the
 solders may be allowed to melt by thermal welding to connect the land
 sections of the vibrator and the land sections of the flexible wiring
 board.
 Furthermore, according to the present invention, an adhesive may be applied
 in sections thermal-welded to connect the land sections of the vibrator
 and the land sections of the flexible wiring board.
 Furthermore, according to the present invention, lead wires are not used;
 but a flexible wiring board is used instead to connect the vibrator and
 the circuit substrate; therefore, the connection strength can be made much
 higher than that of conventional vibratory gyroscopes and the processing
 efficiency can also be improved.
 Furthermore, according to the present invention, since the wiring section
 is narrower, vibration of a circuit substrate is not significantly
 transferred to the vibrator, and conversely, vibration of the vibrator is
 also not significantly transferred to the circuit substrate. This allows a
 detection signal retrieved from the vibrator to be relatively free of
 undesirable vibration influences.
 Furthermore, since the wiring patterns are commonly used, the width of the
 wiring section can be arranged at smaller scales to make it more difficult
 for the transfer of vibration to occur between the circuit substrate and
 the vibrator.
 Furthermore, since the land sections are arranged in the base end section
 of the vibrator held by the holding member and they are connected in this
 base end section to the land sections of the flexible wiring board,
 vibration of the vibrator is not significantly transferred to the circuit
 substrate.
 Furthermore, land sections are arranged on two opposite sides of the
 vibrator, but the single flexible wiring board is sufficient. This allows
 manufacturing cost to be reduced, and compared to the case in which two
 flexible wiring boards are used, also allows the processing-efficiency to
 be improved.
 Furthermore, since the common wiring patterns are arranged in the wiring
 section between the branch section and the circuit-board-side end section,
 even when electrodes having identical potentials are formed on two
 opposite sides of the vibrator, increase in the width of the wiring
 section can be avoided.
 Furthermore, since the wiring section originates centrally from the
 vibrator-side end section, the vibration balance can be improved.
 Furthermore, although plural wiring patterns and electrodes are formed,
 fewer connection processings can be achieved by thermal welding, by which
 the processing efficiency can further be improved.
 Furthermore, even when undesirable forces impinge on the land sections of
 the vibrator and wiring patterns, connections are not broken.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 In FIG. 1, the number 100 represents a vibratory gyroscope having a
 built-in vibrator 1, which will be described later. The vibratory
 gyroscope 100 is, for example, fixed to a fixed board 110 of a vehicle
 navigator.
 The vibrator 1 is of a three-legged tuning fork type (or a two-legged
 tuning fork type) used as a sensor of a gyroscope that generates a
 vibration component according to Coriolis force within a rotation system
 to detect angular velocity.
 As shown in FIG. 5, the vibratory gyroscope 100 is primarily comprised of a
 housing 2 of which an upper portion is open, a holding member 4 fixed
 through a base end section 1A of the vibrator 1, which is sandwiched and
 fixed by a vibration isolation rubber member 3, a flexible wiring board 5
 connected and fixed to the base end section 1A of the vibrator 1 by
 thermal-welding, a substrate (circuit substrate) 6 on which the vibrator 1
 fixed with a holding member 4 is fixed, a cover 7 to cover the opening of
 the housing 2 that accommodates the substrate 6, and a shield cover 8 to
 shield external surfaces of the housing 2 and the cover 7 that are coupled
 into one assembly.
 The vibrator 1 is either like a plate having a surface of an elastic
 material, such as elinbar, on which a piezoelectric material used as a
 driving means and a detecting means is layered, or is like a plate
 entirely formed of the piezoelectric material used as the driving means
 and the detecting means. On the piezoelectric-material surface, driving
 electrodes for driving vibration arms and detection electrodes for
 detecting vibration are formed.
 In this embodiment, the vibrator 1 is a plate formed of a piezoelectric
 ceramic material, such as PZT (lead zirconate titanate). As shown in FIG.
 11, in the vibrator 1, an end portion of the base end section 1A is formed
 in a single unit of three vibration arms 12a, 12b, and 12c, each of which
 is spaced by a gap 11.
 In FIG. 12 dielectric-polarization directions of the vibration arms 12a,
 12b, and 12c are indicated by arrows. As shown therein, the vibration arms
 12b and 12c at the individual right-left ends have the same
 dielectric-polarization directions, and in the vibration arm 12a in the
 center, the dielectric-polarization directions are symmetrical with those
 of the arms 12b and 12c with respect to the up-down and right-left
 directions.
 On each of the vibration arms 12a, 12b, and 12c, a pair of driving
 electrodes 13 made of a conductive material is formed on the bottom face
 (back side) and extends to an end face 1B of the vibrator 1 to form land
 sections 13a and 13b. The land section 13b is connected to two driving
 electrodes 13 through conductive paths. These electrodes 13 are connected
 to an AC driving power source 15 through conductive paths to be supplied
 with driving voltage of the same constant potential.
 The middle vibration arm 12a has a grounding electrode 14 in the back side.
 This grounding electrode 14 is extended to the end face 1B of the vibrator
 1 to form a land section 14a which is a grounding potential through a
 wiring path. The two electrodes applied with the same potential are
 incorporated into one land section 13b in their one-end sections. By this
 arrangement, the number of land sections can be decreased; therefore,
 efficiency of processing such as soldering can be improved.
 A pair of grounding electrodes 16 are formed on the upper face (front
 side), a pair of detection electrodes 17a and 17b are formed on the middle
 vibration arm 12a, and one grounding electrode 16 is formed between the
 detection electrodes 17a and 17b of the middle vibration arm 12a. As shown
 in FIG. 11A, four grounding electrodes 16 formed on the vibration arms 12b
 and 12c are extended up to the end face 1B of the base end sections 1A of
 the vibrator 1 and respective land sections 16b are formed on the base end
 section 1A, while a single grounding electrode 16 formed on the middle
 vibration arm 12a is extended to a position before the end face 1B of the
 vibrator 1 and a land section 16a is formed on the base end section 1A.
 These grounding electrodes are grounding potentials through wiring paths.
 For reference, the driving electrode 13, the grounding electrodes 14 and
 16, and the detection electrodes 17a and 17b print-formed of a
 silver-palladium compound paste, such as a silver paste or a
 silver-palladium paste primarily comprising silver. In this embodiment,
 silver paste, which does not contain expensive palladium, is used. After
 the silver-paste printing, baking is performed to evaporate a solvent used
 to liquefy silver powder and a binder material. Dried electrode patterns
 created in this way are used in this embodiment.
 Regarding the land sections 13a, 13b, and 14a, they are print-formed
 concurrently with the driving electrodes 13 and the grounding electrode
 14. Regarding the land sections 16a and land sections 16b and land
 sections 17a1 and 17bl (to be described later), they are print-formed
 concurrently with the grounding electrode 16 and the detection electrodes
 17a and 17b.
 The driving electrodes 13, the grounding electrode 14, and the grounding
 electrodes 16 provide driving voltage to the piezoelectric material, which
 is a driving means. In accordance with a dielectric polarization structure
 in FIG. 12, the left and right vibration arms 12b and 12c are
 vibration-driven in an X-direction in the same phase, while the middle
 vibration arm 12a is also vibration-driven in the X-direction, but in a
 phase opposite to the phase for the vibration arms 12b and 12c (180-degree
 different phase). That is, at one time, an X-direction amplitude of the
 left and right vibration arms 12b and 12c is in the reverse direction of
 an X-direction amplitude of the middle vibration arm 12a.
 For reference, when the grounding electrode 14 and the grounding electrodes
 16 are not grounded, the vibration arms 12a, 12b, and 12c are not
 vibration-driven. In this case, the grounding electrode 14 and the
 grounding electrodes 16 functions as diving electrodes.
 On an upper face of the middle vibration arm 12a, the pair of detection
 electrodes 17a and 17b is formed. Each of the detection electrodes 17a and
 17b is extended to the position of the end face 1B in the back side of the
 vibrator 1. The respective detection electrodes 17a and 17b have land
 sections 17a1 and 17b1 in a single unit. These land sections 17a1 and 17b1
 are widely formed on the base end section 1A, since the land section 16a
 of the grounding electrode 16 is not extended to reach the end face 1B of
 the base end section 1A of the vibrator 1.
 In FIG. 11, the individual driving electrodes 13 are electrically connected
 to conductive patterns (circuit patterns) of the substrate 6 through
 flexible wiring board 5 (not shown) and further connected to the AC
 driving power source 15. Furthermore, the individual grounding electrode
 14, grounding electrodes 16, and detection electrodes 17a and 17b are also
 connected to predefined conductive patterns of the substrate 6 thorough
 the flexible wiring board 5.
 One end portion of the flexible wiring board 5 is branched into two fork
 edge sections on which a vibrator-front-side-connection end section 5a and
 a vibrator-back-side-connection end section 5b are arranged, respectively,
 and are thermal-welded with front-side and back-side land sections of the
 vibrator 1. On another end portion of the flexible wiring board 5, a
 substrate-connection end section 5c is arranged and is connected to a
 conductive pattern (not shown). Detailed description of individual
 arrangements and connections will be given later.
 The vibrator 1 is held at one end by the holding member 4 to minimize
 components. Furthermore, the base end section 1A of the vibrator 1 is held
 by the holding member 4 to stabilize the vibrator 1. Furthermore, the
 vibrator 1 is fixed on the substrate 6 through the vibration isolation
 rubber member 3; therefore, vibration and shocks externally impinging on
 the substrate 6 can be buffered and the vibrator 1 can be prevented from
 directly transferred shocks and vibration.
 Furthermore, it is notable that in the vibrator 1 of a three-legged tuning
 fork type shown in FIG. 1, the left and right vibration arms 12b and 12c
 and the middle vibration arm 12a vibrate in 180-degree different phase to
 vibrate the vibrator 1 in overall good vibration balance. Therefore, even
 when vibration is caused in the base end section 1A of the vibrator 1, the
 vibration becomes much smaller. According to these arrangements, in a
 state in which the base end section 1A is held by the holding member 4,
 the vibration arms 12a, 12b, and 12c are allowed to vibrate without being
 restricted because of the holding method and driving capability, in which
 detecting sensitivity of the individual vibration arms is not lowered.
 When the mass of the vibration arm is represented by m, the
 X-axis-direction vibration velocity of the vibration arm is represented by
 v (vector value), and the angular velocity at the about-Z-axis rotation in
 a rotation system is represented by .omega.0 (vector value), the Coriolis
 force F is expressed by the following formula:
EQU F=2m(vx.omega.0) (x is a vector product)
 This shows the Coriolis force is proportional to the angular velocity
 .omega.0. Accordingly, the angular velocity can be obtained when the
 Y-axis-direction variation vibration of the vibration arm 12a is detected
 by the detection electrode.
 When the vibrator 1 is placed within a rotation system having an
 about-Z-axis-rotation angular velocity, the individual vibration arms 12a,
 12b, and 12c have a Y-direction vibration component according to the
 Coriolis force as expressed above. Since the vibration arms 12b and 12c at
 the two opposite sides and the vibration arm 12a in the middle have
 vibration phases opposite to each other, the phases according to the
 Coriolis force are also opposite to each other for the vibration arms 12b
 and 12c and the vibration arm 12a. That is, at one time, the Y-axis
 amplitude directions of the vibration arms 12b and 12c according to the
 Coriolis force are the same and are opposite to the Y-axis amplitude
 direction of the middle vibration arm 12a.
 The detection electrodes 17a and 17b are formed on the same face of the
 middle vibration arm 12a, and the piezoelectric material of the arm 12a
 functions as a detecting means to detect the Coriolis force. The
 piezoelectric material areas where the detection electrodes 17a and 17b
 are formed have dielectric polarization directions which oppose each
 other; therefore, with respect to the Y-direction vibration component, the
 detection electrodes 17a and 17b can yield piezoelectric-effect detection
 outputs according to 180-degree different phase. In this case, the
 difference between the detection outputs from these detection electrodes
 17a and 17b is taken out, by which an absolute value of the detection
 outputs from the detection electrodes 17a and 17b is added. This detection
 output is used to allow the about-Z-axis-rotation angular velocity .omega.
 component to be produced.
 As shown in FIGS. 3 and 4, the base end section 1A of the vibrator 1 is
 sandwiched by the vibration isolation rubber member 3 and is then held by
 the holding member 4. As shown in FIG. 5, this holding member 4 comprises
 a holding member case 41 and a holding member cover 42 that is fitted to
 the holding member case 41 containing the vibration isolation rubber
 member 3.
 The holding member case 41 is bent and formed of a 0.3-mm thick
 phosphor-bronze plate. As shown in FIG. 5, this holding member case 41
 comprises a square-plate-like and plane-bottom plate section 41a, side
 plate sections 41b bent and formed at three sides of the plane-bottom
 plate section 41a, fixing tab sections 41c projecting on upper ends of the
 side plate sections 41b for fixing the holding member cover 42, a
 positioning tab section 41d for the vibration isolation rubber member 3
 which is cut and raised to the inside from the opposing side plate
 sections 41b, and fixing tab sections 41e so as to be fitted to the
 substrate 6 projecting on the upper ends of the side plate sections 41b.
 On the holding member cover 42 formed of a 0.5-mm thick
 plane-phosphor-bronze plate, slits 42a in which fixing tab sections 41c
 and 41e and the like are inserted are formed.
 The vibration isolation rubber member 3 made of silicon rubber, which does
 not substantially vary in hardness according to temperature, comprises
 first and second vibration isolation rubber members 31 and 32. As shown in
 FIG. 5, the first vibration isolation rubber member 31 has a concave
 section 31a in which the base end section 1A of the vibrator 1 is
 inserted, a notch section 31b to draw out the flexible wiring board 5
 welded and fixed with the base end section 1A of the vibrator 1, and a
 pair of wall sections 31c forming the notch section 31b. The second
 vibration isolation rubber member 32 is like a square plate and has, on
 the two opposite sides, notch sections 32a in which the wall sections 31c
 are inserted.
 The first vibration isolation rubber member 31 is inserted in the holding
 member case 41. The vibrator 1 is fixed by thermal welding with the base
 end section 1A of the vibrator 1 inserted with the base end section 1A
 into the concave section 31a of the first vibration isolation rubber
 member 31. Further, the second vibration isolation rubber member 32 is
 inserted in such a manner that the base end section IA of the vibrator 1
 is inserted so as to be sandwiched to the wall sections 31c of the first
 vibration isolation rubber member 31 and to the notch sections 32a of the
 second vibration isolation rubber member 32, the holding member cover 42
 is fitted on, and the protruding fixing tab sections 41c are bent. In this
 way, the holding member 4 is fitted to the vibrator 1. In this case, with
 compressibility of the vibration isolation rubber member 3 arranged to be
 10 to 30%, the base end section 1A of the vibrator I is sandwich-fitted by
 the holding member 4 between the first and second vibration isolation
 rubber members 31 and 32. The tab sections 41e of this holding member 4
 are inserted into slits (holes 6b) of the substrate 6 and soldered on the
 rear.
 In this way, as shown in FIG. 4, the vibrator 1 is fixed to the substrate 6
 by the holding member 4 through the vibration isolation rubber member 3.
 This embodiment is used in a state in which the base end section 1A of the
 vibrator 1 is positioned downward and the vibration arms 12a, 12b, and 12c
 are positioned upward.
 The housing 2 is like a square box having an opening in the upper side and
 is formed of a synthetic resin. As shown in FIGS. 9 and 10, it has a
 square bottom section 20, side walls 21 formed on the four sides of the
 bottom section 20, height determination sections 22 arranged inside of the
 side walls 21 which are used to determine the height of the substrate 6,
 fixing ribs 23 to be fitted to notch sections 6a for positioning the
 substrate 6 and to fix the substrate 6 with protruded portions
 thermal-caulked, tapered sections 24 arranged on outside faces of the
 opposing side walls 21 to work as guides for insertion of the shield cover
 8, convex sections 25 continuously formed on the tapered sections 24 to
 work as receiving sections when fall-out prevention tabs 87 of the shield
 cover 8 are bent, notch sections 26 to allow terminals 9 to pass out of
 the housing 2, positioning guide pins 27 for the substrate 6, and tapered
 sections 28 formed on the bottom section 20 to work as a guide when the
 shield cover 8 is inserted. Bottom faces 26a of the notch sections 26 are
 flat surfaces, as shown in FIG. 10.
 As a material of the housing 2 and the cover, an engineering plastic, such
 as PBT (polybutylene terephthalate), PPS (polyphenylene sufide), and ABS
 (acryloritrile-butadience-styrene), may be used. From a viewpoint of
 characteristics for heat resistance and strength, PBT is preferable.
 Furthermore, the bottom section of the housing 2 may be arranged to be an
 opening with a bottom cover used to close the bottom opening.
 The rigid circuit substrate 6 is made of a material such as a
 glass-reinforced epoxy resin and detection circuits and the like are
 mounted thereon. As shown in FIGS. 4 and 5, it also comprises the notch
 sections 6a to receive the fixing ribs 23, the insertion holes 6b to
 receive the fixing tab sections 41e of the holding member case 41, guide
 holes 6c to receive the guide pins 27, and the terminals 9 connected and
 fixed to patterns that are connected to the detection circuits and the
 like. The number 61 represents a semi-fixed variable resistor.
 As shown in FIGS. 3 and 4, the terminal 9 is formed in a two-step shape
 when it is viewed overall. It comprises a first horizontal plate section
 91 that is bent and formed substantially parallel to the surface of the
 circuit substrate 6, a first vertical plate section 92 that is bent and
 formed to be substantially perpendicular to the first horizontal plate
 section 91, and a second horizontal plate section 93 that is bent and
 formed to be substantially perpendicular to the first vertical plate
 section 93.
 The cover 7 is formed like a square plate overall so as to be positioned
 inside of the side walls 21 of the housing 2 so as to close the opening.
 As shown in FIGS. 6 to 8, the cover 7 comprises a concave section
 (internal bottom section) 71 formed on the lower surface of a flat section
 70, side walls 72 formed to surround the concave section 71, tapered face
 sections 73 formed along the periphery of the upper-face side of the flat
 section 70, tapered sections 74 projecting on the upper face side of the
 flat section 70 to work as a guide when the shield cover 8 is inserted, a
 vent 75 used for releasing air in the housing 2 when heating is performed
 to fix the cover 7 and the housing 2 together, and derivation notch
 sections 76 for terminals 9 notch-formed on the side walls 72.
 When viewed overall, the cover 7 is also like an upsidedown dish. As shown
 in FIG. 3, concave gap portions G are formed by the tapered face sections
 73 of the cover 7 and the upper end sections of the side walls 21 of the
 housing 2 along the periphery of the cover 7 (connected section of the
 cover 7 and the housing 2). The concave gap sections G are filled with an
 adhesive S (diagonally broken line portions). This allows the use of the
 adhesive S in only the connected portions of the cover 7 and the housing
 2. For reference, edges of the four corners of the side walls 72 abut on
 circuit substrate 6 to prevent the cover 7 from falling into the housing
 2.
 The shield cover 8 is formed of a single metal plate, such as a copper
 plate. As shown in FIGS. 2 and 5, it comprises a rectangular top plate 81,
 a pair of first side plates 82 obtusely bent and formed at two long sides
 of the top plate 81, auxiliary side plates 83 bent and formed at the two
 sides of the first side plates 82, a pair of second side plates 84 bent
 and formed at the two short sides of the top plate 81, engaging holes 85
 formed closer to free-end sides of the auxiliary side plates 83,
 cut-and-raised tabs 86 formed closer to ends of the second side plates 84
 to be snap-fitted in the engaging holes 85, fall-out prevention tabs 87
 for the housing 2 which are formed at the ends of the second side plates
 84, and fixing tabs 88 for an installation substrate 110 which are formed
 at the ends of the first side plates 82.
 According to the above arrangements, the first side plates 82 widen by more
 than 90 degrees to the top plate 81 and are brought toward each other, and
 the cut-and-raised tabs 86 are snap-fitted into the engaging holes 85. In
 this way, the square-box-like shield cover 8, as shown in FIG. 5, is
 formed.
 Hereinbelow, referring to FIG. 13, description will be given of
 polarization of the piezoelectric material used for the vibrator 1.
 In order to provide ceramics, which is a piezoelectric material, with
 piezoelectric effects, polarization is performed to provide the material
 with dielectric polarization directions as indicated by the arrows in FIG.
 12.
 In this embodiment, an arrangement is made so that six vibrators 1 (FIG.
 11) are created from a single piezoelectric ceramic board 101. For the
 creation of the six vibrators 1, the piezoelectric ceramic board 101 is
 cut along broken lines 102 which define the material in the longitudinal
 direction of the vibrators 1 and along broken lines 103 which are to
 become the end faces 1B of the vibrators 1. In this case, the vibrators 1
 are provided with polarization patterns alternately on the front and back
 sides and a plurality of the vibrators 1 are created. Corresponding
 polarization patterns are also formed on the back side of the
 piezoelectric ceramic board 101 shown in FIG. 13.
 In particular, in FIG. 13, at one side end of the piezoelectric ceramic
 board 101, three vibration arms 12b, 12a, and 12c which are to be surfaces
 of the first vibrator, as viewed from the left, are separately formed with
 the gaps 11, and at a right-adjacent area of the vibration arm 12c, the
 vibration arms 12c, 12a, and 12b which are to be surfaces of the second
 vibrator are formed with predetermined intervals. In the same manner as
 that above, there are formed vibration arms 12b, 12a, and 12c which are to
 be surfaces of the third vibrator in the right-adjacent area of the back
 side of the second vibrator, vibration arms 12c, 12a, and 12b which are to
 be surfaces of the third vibrator in the right-adjacent area of the back
 side of the third vibrator, and so on. In this manner, six vibration arms
 are formed alternately with respect to the front and back sides.
 As described earlier, the pair of detection electrodes 17a and 17b and one
 grounding electrode 16 between them are formed on the individual vibration
 arms 12a, and the pair of grounding electrodes 16 is formed on each of the
 individual vibration arms 12b and 12c. As also described earlier, the pair
 of driving electrodes 13 and one grounding electrode 14 between them are
 formed on the individual vibration arms 12a, and the pair of driving
 electrodes 13 are formed on each of the individual vibration arms 12b and
 12c.
 Hereinbelow, a more detailed description will be given with reference to
 the front side of the piezoelectric ceramic board 101 shown in FIG. 13 as
 an example.
 The left grounding electrode 16 of the vibration arm 12b which is the
 surface of the first vibrator as viewed from the left, voltages of the
 same potential in polarization are applied to the detection electrode 17a
 of the right vibration arm 12a and the left grounding electrode 16 of the
 vibration arm 12c. Therefore, these electrodes are incorporated in one
 conductive pattern 104 in a polarization-pattern forming section 101a in
 an area below the cutting line 103 of the piezoelectric ceramic board 101.
 The left driving electrodes 13 of the vibration arm 12c, the right driving
 electrodes 13 of the vibration arm 12a, and left driving electrodes 13 of
 the vibration arm 12b are connected to the common conductive pattern 104,
 to which voltages of the same potential are applied, in the back side (the
 front side in FIG. 13) of the second vibrator as viewed from the left.
 Thereafter, the electrodes are connected to the common conductive pattern
 104 alternately from the left in the same manner as that of the above
 first vibrator for the odd-numbered vibrators (faces corresponding to the
 front side faces) and in the same manner as that of the second vibrator
 for the even-numbered vibrators (faces corresponding to the back side
 faces).
 Furthermore, the right grounding electrode 16 of the vibration arm 12b and
 the left detection electrode 17b of the vibration arm 12a of the first
 vibrator are connected to a conductive pattern 105 extending independently
 to the polarization-pattern forming section 101a of the piezoelectric
 ceramic board 101 in a manner such that these electrodes are not
 electrically connected to the common conductive pattern 104. The right
 grounding electrode 16 of the vibration arm 12c of the first vibrator is
 also connected to a conductive pattern 105 extending independently to the
 polarization-pattern forming section 110a of the piezoelectric ceramic
 board 101 in a manner such that this electrode is not electrically
 connected to the common conductive pattern 104.
 For reference, the grounding electrode 14 and the grounding electrode 16 of
 the vibration arm 12a are not used for polarization. Since they are
 shorter, as described above, they are not connected to the common
 conductive pattern 104 nor conductive pattern 105.
 In this way, the six vibrators are formed on the piezoelectric ceramic
 board 101, the individual electrodes connected to the conductive pattern
 are connected to the positive electrode and the common conductive pattern
 104 are connected to the positive electrode of a direct current (DC) power
 source 106, and twelve independent conductive patterns 105 are connected
 to the negative electrode of the direct current power source 106. The
 piezoelectric ceramic board 101 is subjected to polarization in which it
 is immersed in silicon oil heated at 100 to 200.degree. C. and 1-kV to
 2-kV DC voltage is applied therethrough from the DC power source 106 for 1
 to 3 hours, as shown in FIG. 12. After the completion of polarization, the
 piezoelectric ceramic board 101 is cut along the cutting lines 102 and 103
 to create the six vibrators 1 shown in FIG. 11.
 As described above, the driving electrodes 13 formed outside of both sides
 of the vibration arms 12b and 12c and the land sections 13a and 16a of the
 grounding electrodes 16 extend up to the end face 1B, not to a side end of
 the vibrators 1, and can be further extended; therefore, a pattern such as
 that to be extended from the side end of the base end section 1A of the
 vibrator 1 is not necessary and the interval between the vibrators on the
 piezoelectric ceramic board 101 can be smaller, i.e., the piezoelectric
 ceramic board 101 can be used more effectively. This reduces the cost for
 manufacturing the vibrators.
 Next, referring to FIGS. 14 to 18, a detailed description will be given of
 arrangements including connection relationships regarding the flexible
 wiring board 5.
 For forming the flexible wiring board 5, a film-like plate made of a
 synthetic resin, such as polyimide or polyethylene, at a total thickness
 of about 50 .mu.m and a width of 1 to 1.5 mm (a wiring section 5d between
 the vibrator and the circuit substrate) can be used. For this embodiment,
 in consideration of heat resistance, it is formed of the polyimide resin.
 As described earlier and as shown in FIG. 14, the flexible wiring board 5
 has on one end the vibrator-front-side-connection end section 5a and the
 vibrator-back-side-connection end section 5b, which are thermal-welded on
 the land sections of the front and back sides of the vibrator 1. On
 another end, it also has substrate-connection end section 5c, which is to
 be connected to a conductive pattern (not shown) of the circuit substrate
 6. These vibrator-front-side-connection end section 5a,
 vibrator-back-side-connection end section 5b, and substrate-connection end
 section 5c are connected through the belt-like wiring section 5d. The
 wiring section 5d originates centrally from each of the connection
 sections 5a, 5b, and 5c to maintain the balance.
 As shown in FIGS. 14 and 18(B), the flexible wiring board 5 is arranged in
 a single unit through wiring patterns 531 to 534 which are sandwiched by
 films 51 and 52. In particular, the wiring patterns 531 to 534 formed of
 silver foil and the individual land sections such as the 531a electrically
 connected to the individual wiring patterns are etching-formed at the same
 time on the film 52 that is a base material, and the protection film 52
 (cover film) is pasted on the film 52 with an adhesive to prevent the
 wiring patterns from short-circuiting or other problems.
 As shown in FIG. 14, on the vibrator-front-side-connection end section 5a
 of the flexible wiring board 5, a land section 531a of the wiring pattern
 531 and land sections 532a and 533a of the two wiring patterns 532 and 533
 are formed. These land sections 531a, 532a, and 533a are exposed from a
 notch section 51a or an opening section 51b formed on the film 51 so as to
 be soldered.
 As shown in FIGS. 15 to 17, the land sections 531a of the
 vibrator-front-side-connection end section 5a are connected to the
 individual land sections 16b of the two grounding electrodes of the
 vibration arm 12b, the land section 16a of the middle grounding electrode
 16 of the vibration arm 12a, and the individual land sections 16b of the
 two grounding electrodes 16 of the vibration arm 12c. The land sections
 532a and 533a of the wiring patterns 532 and 533 are connected to the land
 sections 17bl and 17al of the two detection electrodes 17b and 17a of the
 vibration arm 12a, respectively. The individual land sections 16b of the
 two grounding electrodes 16 of the vibration arm 12b, the land section 16a
 of the middle grounding electrode 16 of the vibration arm 12a, and the
 individual land sections 16b of the two grounding electrodes 16 of the
 vibration arm 12c, which are to have the same potentials, are connected
 through the single continuous wiring pattern 531.
 As shown in FIG. 14, on the vibrator-back-side-connection end section 5b of
 the flexible wiring board 5, four land sections 534a of the wiring pattern
 534 and the single land section 531a electrically connected to the wiring
 pattern 531 are formed. As shown in FIGS. 15 to 17, the individual land
 sections 534a of the vibrator-back-side-connection end section 5b are
 connected to the land section 13a of the left driving electrode 13 of the
 vibration arm 12c, the land section 13b which is common to the right
 driving electrode 13 of the vibration arm 12c and left driving electrode
 13 of the vibration arm 12a, the land section 13b commonly electrically
 connected to the right driving electrode 13 of the vibration arm 12a and
 the left driving electrode 13 of the vibration arm 12b, and the land
 section 13a of the right driving electrodes 13 of the vibration arm 12b.
 The land section 531a of wiring section 531 is connected to the land
 section 14 of the middle land section 14 of the vibration arm 12a.
 For reference, the wiring section 5d is branched into two sections at a
 branch section 5e of the vibrator-front-side-connection end section 5a and
 the vibrator-back-side-connection end section 5b, and the land section
 531a is connected to the wiring pattern 531 branched at the branch section
 5e. These land sections 534a and 531a are also exposed from the notch
 section 51a or the opening section 51b formed on the film 51 so as to be
 soldered.
 The driving electrodes 13 connected as described above have the same
 potentials; therefore, they are connected to the single wiring pattern
 534. According to this arrangement, a total of 14 electrodes of the front
 and back sides are formed on the vibrator 1; however, as a result of
 grouping of the electrodes for the same potential, only the four wiring
 patterns 531 to 534 need to be formed in the wiring section 5d. The
 reduced wiring patterns allows the width of the wiring section 5d to be
 reduced in scale compared to those of the vibrator-front-side-connection
 end section 5a, the vibrator-back-side-connection end section 5b, and
 others.
 By the arrangement in which the width of wiring section 5d is narrowed, the
 wiring section 5d becomes easily flexible to easily absorb vibration;
 therefore, vibration is not significantly transferred from the circuit
 substrate 6 to the vibrator 1, and conversely, is not significantly
 transferred from the vibrator 1 to the circuit substrate 6. This allows a
 detection signal obtained from the vibrator 1 to be relatively free of
 undesirable vibration influences.
 Furthermore, as can be seen in FIG. 3 showing the flexible wiring board 5
 (wiring section 5d), because of a U-shaped section between the vibrator 1
 and circuit substrate 6, the wiring section 5d can be arranged to be
 elastic. In this case, vibration can be easily absorbed in this U-shaped
 section and undesirable vibration is not significantly transferred between
 the vibrator 1 and the circuit substrate 6.
 In FIG. 14, 531b and 534b represent slits formed in the land sections 531a
 and 534a to retain melted solder. In addition, slits 531b, 532b, 533b, and
 534b are formed in land sections 531c, 532c, 533c, and 534c of the
 substrate-connection end section 5c. These land sections 531c, 532c, 533c,
 and 534c are also exposed from the notch section 51c formed on the film 51
 so as to be soldered.
 Corresponding to land sections 13a, 13b, 14a, 16a, 16b, 17a1, and 17b1 of
 the vibrator 1, the individual wiring patterns 531 to 534 of the
 vibrator-front-side-connection end section 5a and
 vibrator-back-side-connection end section 5b, which are thermal-welded,
 comprise solder 59 (hatched portion in FIGS. 15 to 17) formed of solder
 paste, solder-plating, or the like, on the silver foil that is formed by
 etching. These solder 59 is allowed to melt by thermal-welding to connect
 the land sections 13a, 13b, 14a, 16a, 16b, 17a1, and 17b1 and the land
 sections 531a, 532a, 533a, and 534a of the wiring patterns 531 to 534, as
 shown in FIG. 17. In particular, the vibrator-back-side-connection end
 section 5b is arranged so that the corresponding land sections 534a, 534a,
 531a, 534a, and 534a abut on the back-side land sections 13a, 13b, 14a,
 13b, and 13a of the vibrator 1. Then, a heating tip is used to abut on,
 press, and heat the back side (film 52 side) of the
 vibrator-back-side-connection end section 5b. After the solder 59 melts
 and the relative land sections are connected, heating is terminated; and
 after the solder 59 is allowed to harden, the pressure given through the
 heating tip is released. This procedure is also applied to connect the
 land sections on the front side of the vibrator 1 and the corresponding
 land sections of the vibrator-front-side-connection end section 5a.
 By the above arrangements, although a plurality of the land sections 534a,
 534a, 531a, 534a, and 534a and the wiring patterns are formed, a
 single-time thermal-welding connection for each of the front and back
 sides of the vibrator 1 is sufficient. This improves efficiency of
 assembly processing.
 On the soldered sections, an adhesive, such as a thermal-curing adhesive,
 cold-curing adhesive, or ultraviolet-curing adhesive (not shown), may be
 applied. In this embodiment, considering characteristics of fast
 curability, usability in processing, and strength, a ultraviolet-curing
 adhesive (UV-curing adhesive) of a acrylic resin type is applied to coat
 the soldered sections. The application of this UV-curing resin protects
 and reinforces the soldered sections (connected section of the vibrator 1
 and the flexible wiring board 5).
 Furthermore, the land sections 531a and 534b of the wiring patterns 531 and
 534 (among the four wiring patterns 531 to 534) which are thermal-welded
 to the comparatively wider land sections 13a, 13e, 14a, and 16a can be
 arranged to have a larger width. This allows the land sections 531a and
 534a to be made narrower, in spite of the fact that in this embodiment the
 slits 531b and 534b are formed in the center portions of the land sections
 531a and 534a, in which case the patterns of the land sections 531a and
 534a are likely to be wider. Therefore, the solder 59 can be heated more
 quickly through these land sections 531a and 534a to allow the solder to
 melt easily. The melted solder 59 flows into the slits 531b and 534b to
 allow complete thermal welding in a shorter time. Furthermore, since the
 melted solder 59 flows into the slits 531b and 534b, the soldering
 condition can be visually confirmed.
 In the same manner as in the case of the vibrator-backside-connection end
 section 5b, the individual land sections 531c to 534c arranged in the
 substrate-connection end section 5c are thermal-welded by use of the
 solder with corresponding conductive patterns (not shown), and the
 UV-curing adhesive is coated on the connections for reinforcement.
 Furthermore, a description will be given, referring to FIG. 18 as an
 example, which is illustrative of a section of the solder 59 of the wiring
 pattern 531 that is thermal-welded with the land section 14a.
 As shown in FIGS. 15 to 18, a vent 54 is provided on the
 vibrator-back-side-connection end section 5b of the flexible wiring board
 5 so as to be positioned on the end face 1B of the vibrator 1, which is
 connected to the vibrator 1. Furthermore, the vent 54 is communicated with
 the slit 531b of the land section 531a of the
 vibrator-back-side-connection end section 5b (although the slit 531b has
 the film 52). Accordingly, the vibrator-back-side-connection end section
 5b and the vibrator 1 are overlaid and thermal-welded, the solder 59
 melts, the remaining solder 59 fills in the slit 531b, and excess solder
 59a is retained in a portion where the land section 14a exists in the vent
 54.
 For reference, as shown in FIGS. 14 to 17, the vent 54 that forms such a
 solder-retaining section is also arranged in section partially across the
 land sections 532a and 533a of the vibrator-front-side-connection end
 section 5a that is soldered with the land sections 17b1 and 17a1 of the
 vibrator 1.
 Although the invention has been described through its preferred forms, it
 is to be understood that these embodiments are only illustrative and
 various changes and modifications may be imparted thereto without
 departing from the scope of the invention which is limited solely by the
 appended claims.