Frequency adjustment device

Abstract

To provide a frequency adjustment device capable of uniformly processing a metal film of a vibration element.SOLUTION: A frequency adjustment device 10 that adjusts a frequency of a vibrating element 100 includes a placement portion 1 on which the vibrating element 100 is placed, a laser oscillator 2, a reflector 3 that reflects light L from the laser oscillator 2 and emits the light L toward the vibrating element 100 placed on the placement portion 1, a measurement unit 4 that measures a characteristic of the vibrating element 100, and a control unit 5 that controls the laser oscillator 2 in accordance with the characteristic measured by the measurement unit 4.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a frequency adjustment device. [Background technology]

[0002] It is known that the frequency of a vibration element is adjusted by forming a weight made of a metal film on the surface of the vibration element and irradiating the metal film with laser light through laser ablation. For example, Patent Document 1 discloses an adjustment device used in the adjustment process. In this device, adjustment is performed by scanning a laser light with a galvanometer mirror. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-78869 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the adjustment device of Patent Document 1, the incident angle of the laser beam to the metal film changes as the laser beam scans, causing variations in the spot shape of the laser beam. This results in variations in the amount of energy per unit area, making it difficult to uniformly process the metal film of the vibration element. If the metal film is processed non-uniformly, this may affect the characteristics of the vibration element. [Means for solving the problem]

[0005] A frequency adjustment device according to an application example of the present invention is a frequency adjustment device that adjusts the frequency of a vibration element, and comprises a mounting portion on which the vibration element is placed, a laser oscillator, a reflector that reflects light from the laser oscillator and emits it toward the vibration element placed on the mounting portion, a measurement portion that measures the characteristics of the vibration element, and a control portion that controls the laser oscillator in accordance with the characteristics measured by the measurement portion, and is characterized in that the reflector has a plurality of mirrors arranged at a predetermined angle. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is an overall schematic diagram of a frequency adjustment device according to an embodiment; [Figure 2] FIG. 1 is a schematic diagram illustrating a configuration of a Fresnel mirror according to a first embodiment. [Figure 3] FIG. 2 is a plan view illustrating a vibration element. [Figure 4] 10 is a flowchart illustrating a method for adjusting the frequency of a vibration element. [Figure 5] 10A and 10B are plan views illustrating a method for adjusting the frequency of the vibration element. [Figure 6] FIG. 2 is a plan view illustrating a vibration element. [Figure 7] FIG. 10 is a schematic side view illustrating the configuration of a first element of a Fresnel mirror according to a second embodiment. [Figure 8] FIG. 10 is a schematic side view illustrating the configuration of a second element of a Fresnel mirror according to a second embodiment. [Figure 9] 10A and 10B are plan views illustrating a method for adjusting the frequency of the vibration element. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Note that the dimensions or scale of various parts in the drawings may differ from the actual dimensions, and some parts are shown schematically for ease of understanding. For ease of explanation, each drawing illustrates three mutually perpendicular axes: the X-axis, the Y-axis, and the Z-axis. The direction along the X-axis is referred to as the "X-axis direction," the direction along the Y-axis as the "Y-axis direction," and the direction along the Z-axis as the "Z-axis direction." The arrowed side of each axis is also referred to as the "positive side," and the opposite side as the "negative side." A plane parallel to the X-axis and Y-axis is also referred to as the "XY plane," and a plane parallel to the X-axis and Z-axis is also referred to as the "XZ plane." The angle between the normal to the plane on which the laser light is incident and the ray of the laser light is referred to as the "angle of incidence."

[0008] 1. First embodiment 1.1 Overall configuration of frequency adjustment equipment 1 is a schematic diagram of an overall configuration of a frequency adjustment device 10 according to an embodiment. The frequency adjustment device 10 uses laser light L to remove a metal film on the surface of the vibration element 100, thereby adjusting the frequency of the vibration element 100 to a desired value.

[0009] The frequency adjustment device 10 includes a mounting unit 1, a laser oscillator 2, a reflector 3, a measurement unit 4, a control unit 5, and a condenser lens 6.

[0010] 1.2 Explanation of the components that make up the frequency adjustment device 1.2.1 Placement area The vibrating element 100 to be frequency-adjusted is placed on the mounting portion 1. The vibrating element 100 is placed on the surface of the mounting portion 1 on the +Z side.

[0011] The mounting unit 1 may have a prober (not shown) that is electrically connected to the measurement unit 4. The prober is electrically connected to the electrodes 102, 103 (see FIG. 3 ) of the vibration element 100, and transmits an excitation signal of the measured vibration element 100 to the measurement unit 4.

[0012] The mounting section 1 may have an XYZ stage and a θ stage, not shown. The XYZ stage can move the vibration element 100 in the Z-axis direction, X-axis direction, and Y-axis direction shown in FIG. 1. The θ stage can move the vibration element 100 around the Z-axis. This allows the position of the vibration element 100 relative to the laser light L to be adjusted.

[0013] 1.2.2 Laser oscillator Upon receiving a signal from the control unit 5, the laser oscillator 2 emits laser light L toward the reflector 3. The type of laser light L is not particularly limited, and for example, pulsed laser light such as YAG, YVO4, or excimer laser, or continuous wave laser light such as carbon dioxide laser can be used.

[0014] 1.2.3 Reflector The reflector 3 is disposed on the +Z side of the mounting portion 1. The reflector 3 has multiple reflective surfaces arranged at a predetermined angle, and branches the laser light L incident from the laser oscillator 2 by reflecting it at and transmitting it through the reflective surfaces. The branched laser light L is emitted toward the condenser lens 6. The optical axes of the emitted laser light L are along the Z axis and are parallel to each other. In other words, the laser light L is irradiated perpendicularly to the condenser lens 6.

[0015] The spot shapes of the multiple laser beams L emitted from the reflector 3 on the XY plane, i.e., the beam profiles, are circular and aligned with each other. In this embodiment, the reflector 3 is a Fresnel mirror 30 (see FIG. 2), the details of which will be described later. Note that the reflecting surface may also be referred to as a "mirror."

[0016] 1.2.4 Condenser lens The condensing lens 6 is disposed between the reflector 3 and the mounting portion 1. That is, the condensing lens 6 is disposed between the reflector 3 and the vibration element 100 mounted on the mounting portion 1. The condensing lens 6 is disposed so that its optical axis is parallel to the Z axis. The condensing lens 6 condenses each of the multiple laser beams L incident from the reflector 3, and emits the collected laser beams toward the vibration element 100 mounted on the mounting portion 1. In this embodiment, the condenser lens 6 is a microlens array, which condenses the laser light L emitted from the Fresnel mirror 30, thereby increasing the energy density and enabling efficient removal of the metal film.

[0017] The microlens array may be an array of rod lenses bundled together, or may be an array of lenses arranged in a matrix.

[0018] The condenser lens 6 is not particularly limited to a microlens array, and may be, for example, an fθ lens. An fθ lens has a refractive index that changes depending on the angle of the incident laser light L. Here, f is the focal length, θ is the angle, and the relationship between the angle of the irradiation range and the focal length is expressed by the fθ formula. Since the multiple laser light beams L incident on the fθ lens are incident from the reflector 3 in a direction parallel to the Z axis, the multiple laser light beams L emitted from the fθ lens are also directed parallel to the Z axis. In other words, the spot shapes of the multiple laser light beams L emitted from the fθ lens on the XY plane, i.e., the beam profiles, are circular and aligned with each other.

[0019] 1.2.5 Measuring part The measuring unit 4 measures the frequency of the vibration element 100 placed on the mounting unit 1. The measurement is performed by electrically connecting the above-mentioned prober to the electrodes 102, 103 of the vibration element 100. The measuring unit 4 may be able to measure electrical characteristics of the vibration element 100 other than the frequency, for example, the crystal impedance, i.e., the equivalent series resistance when there is no load capacitance. The measuring unit 4 transmits the measurement results to the control unit 5.

[0020] 1.2.6 Control Unit The control unit 5 receives a signal from the measurement unit 4 and controls the laser oscillator 2 in accordance with the characteristics measured by the measurement unit 4. The control items include the irradiation energy of the laser light L irradiated onto the vibration element 100. The irradiation energy may be controlled by the irradiation time.

[0021] 1.3 Fresnel mirror Next, the Fresnel mirror 30 serving as the reflector 3 will be described with reference to FIG. 2. FIG. 2 is a schematic diagram showing the configuration of the Fresnel mirror 30. The Fresnel mirror 30 is made up of a plurality of mirrors 33 to 38 and a glass portion 39. The mirrors 33 to 38 are half mirrors. The laser light L0 that is incident on the mirrors 33 to 38 is designated L0. The incident laser light L0 is separated into reflected light and transmitted light by the mirrors 33 to 38. As a result, the incident laser light L0 is split into a plurality of laser light L, which are emitted as output light L21 to L29.

[0022] Fresnel mirror 30 includes a first element 31 and a second element 32. Mirrors 33 to 35 included in first element 31 and mirrors 36 to 38 included in second element 32 each function as a beam splitter. In FIG. 2, second element 32 is disposed on the -X side of first element 31, and first element 31 and second element 32 are in close contact with each other. Laser light L0 from laser oscillator 2 is incident on first element 31. An incident surface 391 onto which laser light L0 is incident is disposed on the -Y side end face of first element 31, and an exit surface 392 from which output light L21 to L29 is emitted is disposed on the -Z side end face of second element 32.

[0023] The mirrors 33 to 38 are made of a dielectric multilayer film. By using a dielectric multilayer film for the mirrors 33 to 38, it is possible to adjust the transmittance and reflectance of the laser light L. Furthermore, instead of a dielectric multilayer film, the mirrors 33 to 38 may be made of a material containing, for example, a metal such as gold (Au) or silicon (Si). This makes it possible to accommodate laser light L0 on the long wavelength side, such as in the infrared region, and to efficiently process metal films.

[0024] Glass portion 39 holds mirrors 33 to 38 and transmits laser light L0. Glass portion 39 and mirrors 33 to 35 are arranged alternately in the Y-axis direction. Mirror 33 is arranged furthest on the -Y side among mirrors 33 to 35. Glass portion 39 and mirrors 36 to 38 are arranged alternately in the X-axis direction. Mirror 36 is arranged furthest on the +X side among mirrors 36 to 38. The material of glass portion 39 is not particularly limited as long as it is capable of transmitting laser light L0, and is, for example, quartz glass.

[0025] The first element 31 has multiple mirrors 33 to 35 arranged along the Y-axis direction. There is no particular limitation on the number of mirrors 33 to 35, but for simplicity of explanation, the present embodiment uses three. The mirrors 33 to 35 are parallel to the Z-axis and tilted at 45° counterclockwise from the X-axis when viewed from the -Z side.

[0026] Laser light L0 is emitted from laser oscillator 2 in the +Y direction and enters incident surface 391 from the -Y side. The incident laser light L0 is separated by mirror 33 into reflected light R1 and transmitted light T1. Transmitted light T1 is separated by mirror 34 into reflected light R2 and transmitted light T2. Transmitted light T2 is separated by mirror 35 into reflected light R3 and transmitted light (not shown). Reflected light R1, R2, and R3 travel in the -X direction, and transmitted light T1, T2, and T3 travel in the +Y direction.

[0027] In the first element 31, the reflectances of mirrors 33 to 35 are 10% for mirror 33, 11.1% for mirror 34, and 12.5% ​​for mirror 35. In this way, when the energy of the incident laser light L0 is taken as 100%, the energy of reflected light R1 is 10% and the energy of transmitted light T1 is 90%. The energy of reflected light R2 is 9.99%, or approximately 10%. The energy of transmitted light T2 is 80%, so the energy of reflected light R3 is 10%. In this way, the reflected lights R1, R2, and R3 split into three by the first element 31 are emitted toward the second element 32 with approximately equal energies.

[0028] The second element 32 has multiple mirrors 36-38 arranged along the X-axis direction. There is no particular limitation on the number of mirrors 36-38, but for simplicity of explanation, three are used in this embodiment. The surfaces of the mirrors 36-38 are parallel to the Y-axis and are tilted at 45° counterclockwise from the X-axis when viewed from the -Y side.

[0029] Reflected light R1 to R3 reflected by first element 31 is incident on second element 32. In second element 32, incident reflected light R1, R2, R3 is separated by mirror 36 into reflected light L11, L12, L13 and transmitted light T3, T4, T5. Reflected light L11, L12, L13 travel in the −Z direction and are emitted from second element 32 as emitted light L21 to L23, and transmitted light T3, T4, T5 travel in the −X direction.

[0030] The transmitted light beams T3, T4, and T5 are separated into reflected light beams L14, L15, and L16 and transmitted light beams T6, T7, and T8 by the mirror 37. The reflected light beams L14, L15, and L16 travel in the −Z direction and are emitted from the second element 32 as emitted light beams L24 to L26, while the transmitted light beams T6, T7, and T8 travel in the −X direction.

[0031] The transmitted light beams T6, T7, and T8 are separated into reflected light beams L17, L18, and L19 and transmitted light beams (not shown) by the mirror 38. The reflected light beams L17, L18, and L19 travel in the −Z direction and are emitted from the second element 32 as emitted light beams L27 to L29.

[0032] In the second element 32, the reflectance of the mirrors is 10% for mirror 36, 11.1% for mirror 37, and 12.5% ​​for mirror 38. The energy of reflected light R1, R2, and R3 incident on mirror 36 is 10%, so the energy of reflected light L11, L12, and L13 is 1%, and the energy of transmitted light T3, T4, and T5 is 9%. The energy of reflected light L14, L15, and L16 is 1%. The energy of transmitted light T6, T7, and T8 is 8%, so the energy of reflected light L17, L18, and L19 is 1%. In this way, the three reflected light beams R1, R2, and R3 incident on the second element 32 are split into nine reflected light beams L11 to L19 by the second element 32. The reflected light beams L11 to L19 are emitted as emitted light beams L21 to L29 from the second element 32 toward the condenser lens 6 with approximately equal energy.

[0033] 2, the laser light L is shown as a line, but the width of the beam of laser light L, i.e., the size of the cross-sectional area, is not particularly limited. For example, the beam of incident laser light L0 may have a cross-sectional area that occupies the entire surface of mirror 33. This allows the matrix of output beams L21 to L29 to be seamless. The number of matrixes of output beams L21 to L29 or the size of the irradiation area can also be set arbitrarily depending on the width of the beam of incident laser light L0 and the number of mirrors 33 to 38.

[0034] The incident surface 391 of the first element 31 is inclined with respect to the XZ plane so that the laser light L0 is incident at the Brewster angle. This makes it possible to minimize energy loss caused by the laser light L0 being reflected on the incident surface 391. The magnitude of the incident angle of the laser light L0 with respect to the incident surface 391 is not particularly limited and may be set arbitrarily.

[0035] The exit surface 392 of the second element 32 has an AR coating, i.e., an anti-reflection coating. This reduces the reflection of the reflected light L11 to L19 at the exit surface 392, thereby maximizing the energy utilization efficiency. Note that there is no particular limitation on whether the exit surface 392 has an AR coating; for example, the exit surface 392 may not have a coating, or may have some kind of coating for some other purpose.

[0036] The Fresnel mirror 30 according to this embodiment is not limited to emitting a plurality of laser beams L having uniform energy, and can, for example, intentionally adjust the energy distribution. By appropriately setting the reflectance and transmittance of the mirrors 33 to 38, the energy distribution of the emitted beams L21 to L29 within the irradiation surface can be adjusted. In this way, it is possible to adjust the distribution of the processing amount on the metal surface to be processed, and for example, it is also possible to form a slope region in the thickness direction on the metal surface to be processed.

[0037] The frequency adjusting device 10 of this embodiment does not need to use a galvanometer scanner axis mirror, so the frequency adjusting device 10 can be provided at low cost.

[0038] Furthermore, frequent calibration work in response to environmental changes, as is required when using a galvanometer scanner axis mirror, is not required. Also, the spot S1 (see FIG. 5) of the laser light L can be easily set to the target position. Therefore, an easy-to-use frequency adjustment device 10 can be provided.

[0039] 1.4 Frequency adjustment method Next, a frequency adjusting method in the frequency adjusting step will be described with reference to Fig. 3 to Fig. 5. Fig. 3 is a plan view illustrating the vibration element 100. Fig. 4 is a flowchart illustrating the frequency adjusting method. Fig. 5 is a plan view illustrating the frequency adjusting method of the vibration element 100.

[0040] The vibration element 100 has a vibration body 101 made of quartz crystal, and electrodes 102 and 103 arranged on the front and back surfaces of the vibration body 101. The electrodes 102 and 103 are made of metal films. In the frequency adjustment process, the vibration element 100 is arranged within the plane of a quartz crystal wafer 104 and is connected to a frame portion 105 of the quartz crystal wafer 104.

[0041] In this embodiment, the vibrating body 101 is a so-called AT-cut quartz crystal plate, and functions as a vibrator or oscillator when housed in a package (not shown). Because the vibrating body 101 is an AT-cut quartz crystal plate, its primary vibration is thickness-shear vibration. In thickness-shear vibration, the frequency is inversely proportional to the thickness of the quartz crystal plate, so the thickness of the quartz crystal plate is controlled at the manufacturing site, but the frequency can be adjusted with high precision by changing the thickness of the electrode 102.

[0042] In the frequency adjustment process, first, in step S101, the vibration element 100 is placed on the mounting portion 1. At this point, the frequency of the vibration element 100 is lower than a desired value.

[0043] Next, in step S102, the measurement unit 4 measures the frequency of the vibration element 100. In addition to the frequency, other characteristic values ​​may be measured.

[0044] Next, in step S103, the control unit 5 calculates the energy with which the laser light L is irradiated onto the vibration element 100. Then, the control unit 5 transmits a control signal based on the calculated energy to the laser oscillator 2. The control unit 5 controls the time during which the laser oscillator 2 irradiates the laser light L. The irradiation energy may be controlled by the irradiation time.

[0045] Next, in step S104, the laser oscillator 2 irradiates the Fresnel mirror 30 with laser light L based on a control signal from the control unit 5. The laser light L0 incident on the Fresnel mirror 30 is branched into nine outgoing beams L21 to L29 arranged in, for example, 3 rows and 3 columns, and then emitted. The emitted outgoing beams L21 to L29 are condensed by the condenser lens 6 and, as shown in FIG. 5, are irradiated onto the electrode 102 of the vibration element 100 as nine spots S1. The nine spots S1 irradiated onto the electrode 102 cause laser ablation, removing the surface of the electrode 102.

[0046] At this time, since the laser profiles of the plurality of output beams L21 to L29 are uniform, there is little variation in the energy of the output beams L21 to L29 within the irradiation area. That is, the electrode 102 is uniformly processed within the area irradiated with the plurality of output beams L21 to L29. Therefore, in the AT-cut vibration element 100 that performs thickness slip, it is possible to suppress the occurrence of problems in vibration characteristics, such as the occurrence of spurious signals, caused by unevenness in the thickness of the electrode 102.

[0047] In step S104, there is no particular limitation to the stage of the mounting unit 1 being stationary while the laser light L is being irradiated. For example, while the laser light L is being irradiated, the XYZ stage may be driven to move the vibration element 100 within the XY plane.

[0048] Next, in step S105, the measurement unit 4 measures the frequency of the vibration element 100.

[0049] Next, in step S106, the control unit 5 determines, based on the measurement result in step S105, whether or not it is necessary to irradiate additional laser light L. If it is determined that it is necessary, steps S103 to S106 are repeated. If it is determined that it is not necessary, the process proceeds to step S107.

[0050] In step S107, the control unit 5 determines whether to process the next vibration element 100. If it is determined that the vibration element 100 is to be processed, the process proceeds to step S108, where the vibration element 100 is moved by moving the mounting unit 1, and the process returns to step S102. If it is determined that the vibration element 100 is not to be processed, the frequency adjustment process ends.

[0051] As described above, the frequency adjustment device 10 in this embodiment can simultaneously irradiate the metal film of the vibration element 100 with a plurality of laser beams L at the same incident angle, instead of scanning the laser beam L. This reduces variation in the shape of the spots S1 of the plurality of laser beams L, thereby reducing variation in the amount of energy per unit area in the irradiation region. Therefore, the metal film can be processed uniformly, and the frequency can be adjusted while suppressing defects in the characteristics of the vibration element 100.

[0052] As described above, the laser light L0 from the laser oscillator 2 is incident on the first element 31, and the reflected light R1, R2, and R3 reflected by the first element 31 are incident on the second element 32. In this manner, the laser light L is divided into n parts by the first element 31, and the laser light L divided by the first element 31 can be divided into m parts by the second element 32. Here, n and m are integers equal to or greater than 2. As a result, n × m beams of laser light L are emitted from the Fresnel mirror 30. Therefore, a wide area can be irradiated with the laser light L simultaneously, and the metal film of the vibration element 100 can be processed more uniformly.

[0053] In the frequency adjustment device 10 of this embodiment, the vibration element to be frequency-adjusted is not particularly limited to the vibration element 100 having an AT-cut quartz crystal plate. For example, it may be a vibration element 200 for a tuning-fork type quartz crystal unit as shown in FIG. 6. The vibration element 200 has a vibration body 201, an electrode 202 disposed on the vibration body 201, and a weight 203 as a metal film for frequency adjustment. The vibration body 201 has a base 204 and a pair of vibration arms 205 and 206 extending from the base 204 in the +Y direction. The vibration body 201 is formed from a Z-cut quartz crystal plate. The metal film processed for frequency adjustment is the weight 203 or the electrode 202.

[0054] In the frequency adjustment device 10 of this embodiment, the vibration element to be frequency-adjusted may be any element capable of measuring frequency and having a metal film for adjusting frequency. For example, it may be an element for a gyro sensor, an element for an angular velocity sensor, or an element for various physical sensors.

[0055] The constituent material of the vibrating body 101 is not particularly limited, and examples thereof include lithium niobate (LiNbO), lithium tantalate (LiTaO), lead zirconate titanate (PZT), lithium tetraborate (LiBO), langasite (LaGaSiO), and the like. 14 ), potassium niobate (KNbO3), gallium phosphate (GaPO4), gallium arsenide (GaAs), aluminum nitride (AlN), zinc oxide (ZnO, Zn2O3), barium titanate (BaTiO3), lead titanate (PbTiO3), potassium sodium niobate ((K,Na)NbO3), bismuth ferrite (BiFeO3), sodium niobate (NaNbO3), bismuth titanate (Bi4Ti3O 12 ), bismuth sodium titanate (Na 0.5 Bi 0.5 Various piezoelectric materials such as TiO3 may be used, or materials other than piezoelectric materials such as a silicon substrate may be used.

[0056] The form in which the vibration element 100 is frequency adjusted has been described as a state in which the vibration element 100 is within the wafer surface, but this is not particularly limited, and for example, the vibration element 100 may be in an individual piece state or may be mounted in a package not shown.

[0057] 2. Second embodiment A frequency adjustment device 10 according to the second embodiment will be described with reference to FIGS. 7 to 9. The difference from the first embodiment is the configuration of the reflector 3, which in this embodiment is formed by a Fresnel mirror 300. The Fresnel mirror 300 includes a first element 301 and a second element 302. FIG. 7 is a schematic side view illustrating the configuration of the first element 301 of the Fresnel mirror 300. FIG. 8 is a schematic side view illustrating the configuration of the second element 302 of the Fresnel mirror 300. FIG. 9 is a plan view illustrating a method for adjusting the frequency of the vibration element 110. The frequency adjustment device 10 according to the second embodiment differs from the first embodiment in the configurations of the first element 301 and the second element 302 of the Fresnel mirror 300, and the magnitude of the angle of incidence and the width of the beam of laser light L emitted from the laser oscillator 2 and incident on the first element 301.

[0058] First, the first element 301 will be described. In the first element 301, multiple mirrors 303 to 307 are arranged along the Y-axis direction. There is no particular limitation on the number of mirrors 303 to 307, but for simplicity of explanation, five mirrors are used in this embodiment. The surfaces of the mirrors 303 to 307 are parallel to the Z-axis and are tilted 30° counterclockwise from the X-axis when viewed from the +Z side. Note that the incident surface is not shown in FIG. 7.

[0059] Positions PM1, PM4, PM7, PM10, and PM13 are the +X side end portions of each mirror 303 to 307. Positions PM2, PM5, PM8, PM11, and PM14 are the middle portions in the X-axis direction of each mirror 303 to 307. Positions PM3, PM6, PM9, PM12, and PM15 are the -X side end portions of each mirror 303 to 307.

[0060] The reflectance of mirror 303, located at the end in the -Y direction, is 10% across its entire surface. That is, the reflectance is uniform at positions PM1, PM2, and PM3. The reflectances of the other mirrors 304-307 gradually increase from the +X side to the -X side within the plane. Specifically, the reflectance of mirror 304 is 10.2% at position PM4, 11.11% at position PM5, and 11.11% at position PM6. The reflectance of mirror 305 is 10.1% at position PM7, 11.36% at position PM8, and 12.5% ​​at position PM9. The reflectance of mirror 306 is 10.62% at position PM10, 11.62% at position PM11, and 12.82% at position PM12. The reflectance of mirror 307 is 11.81% at position PM13, 11.89% at position PM14, and 13.15% at position PM15. The transmittance of the mirrors 303 to 307 is 98%.

[0061] +X side ends of mirrors 303 to 307 are connected to surface A on the +X side of first element 301. Furthermore, -X side ends of mirrors 303 to 307 are connected to surface B on the -X side of first element 301. Surfaces A, B, and the area sandwiched between surfaces A and B constitute a light guide plate.

[0062] In FIG. 7, laser light L incident on first element 301 is shown as light beam BW. The width of light beam BW is greater than the distance along the X axis from surface A to surface B. Laser beams B1 to B6 are portions of light beam BW shown as straight lines, and when viewed from the +Z side, laser beam B1 and laser beam B6 are at both ends of light beam BW, with laser beams B2 to B5 located inside them. Also, dashed-dotted line CL is the central light of light beam BW, and in plan view from the +Z axis direction, laser beams B1 to B3 are located on the +X side of dashed-dotted line CL, and laser beams B4 to B6 are located on the -X side of dashed-dotted line CL.

[0063] A light beam BW is emitted from the laser oscillator 2 toward the surface A. The angle of incidence θ1 of the light beam BW with respect to the surface A is 60°. Of the light beam BW, laser beams B2 to B4 are totally reflected by the surface A and then incident on the mirror 303. The angle of incidence θ2 of the laser beams B2 to B4 incident on the mirror 303 is 60°. The laser beam B2 is split into reflected light RM3 and transmitted light TM3 at the position PM3, the laser beam B3 is split into reflected light RM2 and transmitted light TM2 at the position PM2, and the laser beam B4 is split into reflected light RM1 and transmitted light TM1 at the position PM1.

[0064] Laser light B5 passes through mirror 303, is totally reflected by surface A, and then enters mirror 304. The incident angle θ2 of laser light B5 entering mirror 304 is 60°. Laser light B5 is split into reflected light RM4 and transmitted light TM4 at position PM4.

[0065] After passing through mirrors 303 and 304, laser light B6 is totally reflected at surface A and enters mirror 305. The incident angle θ2 of laser light B6 entering mirror 305 is 60°. Laser light B6 is split into reflected light RM7 and transmitted light TM7 at position PM7.

[0066] Laser light B1 is totally reflected from surface A and then surface B, and then passes through mirror 303, mirror 304, and mirror 305. Laser light B1 is then totally reflected again from surface A and then incident on mirror 306. The incident angle θ2 of laser light B1 incident on mirror 306 is 60°. Laser light B1 is split into reflected light RM10 and transmitted light TM10 at position PM10.

[0067] Although a detailed description will be omitted, reflected light RM1 to RM15 is generated in the manner described above. In this manner, the number of times that laser light B1 to B6 is split into reflected light and transmitted light by mirrors 303 to 307 and the number of times that it is totally reflected by surfaces A and B differ. Therefore, by setting the reflectance of mirrors 303 to 307 as described above, when the energy of light beam BW incident on first element 301 is taken as 100%, the energy of reflected light RM1 to RM15 reflected at positions PM1 to PM15 can be adjusted to 10%, respectively.

[0068] The width of the light beam BW incident on the first element 301 is not particularly limited, but it is desirable that the laser light L fills the space between the surface A and the surface B in plan view from the Z axis direction.

[0069] In this way, reflected light RM1 to RM15 branched by first element 301 is emitted with approximately equal energy toward second element 302 (see FIG. 8). Note that, since the angles at which laser light B1 to B6 enter mirrors 303 to 307 are 60°, the profile of reflected light RM1 to RM15 emitted from first element 301 in a cross section perpendicular to the optical axis is an ellipse elongated in the Y-axis direction.

[0070] Next, the second element 302 will be described. In Fig. 8, reflected light RM1 and emitted light LM1-LM3 are represented by lines. Fig. 8 is a plan view seen from the -Y axis direction, and shows only the path of reflected light RM1, which is located furthest on the -Y side among reflected light RM1-RM15 emitted from the first element 301.

[0071] Second element 302 has multiple mirrors 308-310 arranged along the X-axis direction. There is no particular limitation on the number of mirrors 308-310, but for simplicity of explanation, this embodiment uses three. Mirrors 308-310 have surfaces parallel to the Y-axis and are tilted 30° counterclockwise from the X-axis when viewed from the -Y side. This tilt angle differs from that of the first embodiment.

[0072] In this embodiment, the reflectance of second element 302 is 10% for mirror 308, 11.1% for mirror 309, and 12.5% ​​for mirror 310. The arrangement and reflectance of mirrors 308 to 310 are the same as those of second element 32 in the first embodiment, and therefore detailed description will be omitted. As a result, reflected light RM1 to RM15 incident on second element 302 is each branched into three laser beams L. The energy of the branched laser beams L is approximately equal to one another.

[0073] By setting the tilt angles of mirrors 308 to 310 as described above, the angle of incidence θ3 of laser light L on mirrors 308 to 310 becomes 60°. As a result, the profile of laser light L emitted from second element 302 in a cross section perpendicular to the optical axis is stretched in the X-axis direction. In other words, the profile deformed in first element 301 can be corrected in second element 302. Therefore, laser light L emitted from second element 302 has little energy variation within the spot.

[0074] In this way, the laser light L incident on the first element 301 is branched by the first element 301 and the second element 302, and the branched laser light L is emitted from the second element 302 with approximately equal energy toward the condenser lens 6. The laser light L is condensed by the condenser lens 6, and as shown in FIG. 9, matrix-shaped spots S2 are irradiated onto the electrodes 112 of the vibration element 110.

[0075] As described above, the incident light beam BW can be made larger than the distance from surface A to surface B. This reduces restrictions on the laser oscillator 2 that can be used, making it possible to provide an inexpensive frequency adjustment device 10.

[0076] Furthermore, since the light beam BW is incident on the first element 301 at an angle with respect to the Y-axis direction, there is a high degree of freedom in the position where the laser oscillator 2 is disposed. This reduces the likelihood that the frequency adjustment device 10 will become unusable due to reasons such as the operating environment of the frequency adjustment device 10. Furthermore, since there is a high degree of freedom in the design of the frequency adjustment device 10, it is possible to provide an inexpensive frequency adjustment device 10.

[0077] 8, the optical axes of the output beams LM1 to LM3 emitted from the second element 302 are tilted clockwise from the -Z axis direction when viewed from the -Y side. At least one of the position and attitude of the laser oscillator 2 and the position and attitude of the Fresnel mirror 300 is adjusted so that the output beams LM1 to LM3 are incident on the condenser lens 6 perpendicularly.

[0078] Furthermore, in this embodiment, by narrowing the pitch between the mirrors 303 to 307 or between the mirrors 308 to 310, it is possible to arrange the spots S2 of the irradiated laser light L adjacent to each other in a matrix or to make the spots S2 of the irradiated laser light L overlap each other.

[0079] Although the frequency adjustment device 10 has been described above based on the illustrated embodiment, this embodiment is not limited to this, and the configuration of each part can be replaced with any configuration having the same function. Furthermore, any other components may be added to this embodiment. Furthermore, each embodiment may be combined as appropriate.

[0080] The Fresnel mirror 30 in this embodiment is not limited to having the second element 32, and for example, the laser light L emitted from the first element 31 may be directly incident on the condenser lens 6. This allows the Fresnel mirror 30 to be made compact, making it possible to provide a compact frequency adjustment device 10. Furthermore, the spots S1 of the multiple laser lights L irradiated onto the vibration element 100 can be aligned in a row. This means that the vibration elements 100 that can perform frequency adjustment are not limited, making it possible to provide a highly versatile frequency adjustment device 10.

[0081] The frequency adjustment device 10 in this embodiment is not necessarily limited to having a condenser lens. Therefore, the reflector 3 reflects the laser light L incident from the laser oscillator 2 and emits it toward the vibration element 100 placed on the mounting portion 1.

[0082] The components of the frequency adjusting device 10 in this embodiment may be integrated or may be separate bodies. Also, some of them may be unitized. [Explanation of symbols]

[0083] 1...Placement portion, 2...Laser oscillator, 3...Reflector, 4...Measuring portion, 5...Control portion, 6...Condenser lens, 10...Frequency adjustment device, 30...Fresnel mirror, 31...First element, 32...Second element, 33-38...Mirror, 39...Glass portion, 100...Vibration element, 101...Vibrating body, 102, 103...Electrodes, 104...Crystal wafer, 105...Frame portion, 110...Vibration element, 112...Electrode, 200...Vibration element, 201...Vibrating body, 202...Electrode, 203...Weight, 204...Base, 205, 206...Vibrating arm, 300...Fresnel mirror, 3 01...first element, 302...second element, 303-310...mirrors, 391...incident surface, 392...exit surface, A, B...surface, B1-B6...laser light, CL...dash line, L, L0...laser light, L11-L19...reflected light, L21-L29...exit light, LM1-LM3...exit light, PM1-PM15...position, R1-R3...reflected light, RM1-RM15...reflected light, S1, S2...spot, T1-T3...transmitted light, TM1-TM4, TM7, TM10...transmitted light, S101-S108...step, θ1, θ2, θ3...incident angle

Claims

1. A frequency adjusting device that adjusts the frequency of a vibration element, a mounting portion on which the vibration element is mounted; A laser oscillator; a reflector that reflects light from the laser oscillator and emits the light toward the vibration element placed on the placement section; a measurement unit for measuring characteristics of the vibration element; a control unit that controls the laser oscillator in accordance with the characteristics measured by the measurement unit, The frequency adjusting device is characterized in that the reflector has a plurality of mirrors arranged at a predetermined angle.

2. The reflector is a first element and a second element each including the plurality of mirrors; the light from the laser oscillator is incident on the first element; The frequency adjusting device according to claim 1 , wherein the light reflected by the first element is incident on the second element.

3. 3. The frequency adjustment device according to claim 1, wherein the plurality of mirrors are made of a dielectric multilayer film.

4. 3. The frequency adjustment device according to claim 1, further comprising a condenser lens between the reflector and the vibration element placed on the placement section.

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