oscillator

Abstract

Oscillator. The present invention provides an oscillator in which external heat is less likely to be transmitted to a vibrating element, and which has stable frequency characteristics. The oscillator has: an outer package; an inner package housed in the outer package and fixed to the outer package via a heat-insulating member; a vibrating element housed in the inner package; a temperature sensor; a first circuit element including an oscillation circuit that causes the vibrating element to oscillate and generates an oscillation signal that is temperature-compensated based on the temperature sensor, the first circuit element being housed in the inner package; and a second circuit element fixed to the outer package and including a frequency control circuit that controls the frequency of the oscillation signal.

Description

Technical Field

[0001] This invention relates to oscillators. Background Technology

[0002] Patent Document 1 discloses an oscillator comprising: an outer package; an inner package housed within the outer package; a vibrating element housed within the inner package; and circuit elements housed within the outer package and disposed on the inner package. Furthermore, in the oscillator of Patent Document 1, a temperature sensor is included in the circuit elements, and the frequency of the output signal is corrected based on the temperature detected by the temperature sensor.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2017-175202 Summary of the Invention

[0004] The problem that the invention aims to solve

[0005] However, in the oscillator of Patent Document 1, the circuit element containing the temperature sensor is located outside the inner package housing the vibrating element. Therefore, a temperature difference between the temperature sensor and the vibrating element is easily generated, making it difficult to perform high-precision correction of the output signal. Consequently, the frequency accuracy of the output signal may be reduced.

[0006] Methods for solving problems

[0007] The oscillator of the present invention comprises: an outer package; an inner package housed within the outer package and fixed to the outer package via a heat-insulating member; a vibrating element housed within the inner package; a temperature sensor; a first circuit element comprising an oscillation circuit that causes the vibrating element to oscillate and generate an oscillation signal after temperature compensation based on the temperature sensor, the first circuit element being housed in the inner package; and a second circuit element fixed to the outer package, comprising a frequency control circuit that controls the frequency of the oscillation signal. Attached Figure Description

[0008] Figure 1 This is a cross-sectional view showing the oscillator of the first embodiment.

[0009] Figure 2 It is shown Figure 1 The oscillator has a top view inside the inner package.

[0010] Figure 3 yes Figure 1 The circuit diagram of the second circuit element of the oscillator.

[0011] Figure 4 This is a cross-sectional view showing the oscillator of the second embodiment.

[0012] Figure 5This is a cross-sectional view showing the oscillator of the third embodiment.

[0013] Figure 6 This is a cross-sectional view showing the oscillator of the fourth embodiment.

[0014] Label Explanation

[0015] 1 Oscillator; 2 External Package; 3 Temperature Compensated Quartz Oscillator; 4 Second Circuit Element; 5 Internal Package; 6 Vibration Element; 7 First Circuit Element; 8 Thermal Insulation Component; 21 Second Base Substrate; 21a Upper Surface; 21b Lower Surface; 22 Second Cover; 23 Connecting Component; 40 PLL Circuit; 41 Phase Comparator; 42 Charge Pump; 43 Low-Pass Filter; 44 Voltage-Controlled Oscillator Circuit; 45 Frequency Divider Circuit; 48 Storage Unit; 49 Output Circuit; 51 First Base Substrate; 51a Upper Surface; 51b Lower Surface; 52 First Cover; 53 Connecting Component; 61 Quartz Substrate; 71 Temperature Sensor; 72 Oscillator Circuit; 81 Columnar Section; 211, 21 1a, 211b, 211c, 211d recesses; 212, 212a, 212b recesses; 241, 242 internal terminals; 243 mounting terminal; 481 temperature calibration gauge; 511, 511a, 511b, 511c recesses; 541, 542 internal terminals; 543 external terminal; 621 first excitation electrode; 622 first pad electrode; 623 first lead electrode; 631 second excitation electrode; 632 second pad electrode; 633 second lead electrode; 721 oscillation circuit section; 722 temperature compensation circuit section; B bonding component; BW2, BW3, BW4 bonding wires; S1 first storage space; S2 second storage space. Detailed Implementation

[0016] Hereinafter, preferred embodiments of the oscillator of the present invention will be described in detail with reference to the accompanying drawings.

[0017] <First Implementation>

[0018] Figure 1 This is a cross-sectional view showing the oscillator of the first embodiment. Figure 2 It is shown Figure 1 The oscillator has a top view inside the inner package. Figure 3 yes Figure 1 The circuit diagram of the second circuit element of the oscillator. Additionally, for ease of explanation, in Figure 1 as well as Figure 2 The diagram illustrates the mutually orthogonal X-axis, Y-axis, and Z-axis. Furthermore, 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. Additionally, the arrow side of the thickness direction of oscillator 1, i.e., the Z-axis direction, is referred to as "up," and the opposite side as "down." Furthermore, the top view from the Z-axis direction is simply referred to as "top view."

[0019] Figure 1 The oscillator 1 shown has an outer package 2, a temperature-compensated quartz oscillator 3 (TCXO), and a second circuit element 4. In addition, the temperature-compensated quartz oscillator 3 includes an inner package 5, and an oscillating element 6 and a first circuit element 7 housed in the inner package 5.

[0020] The external package 2 has a second base substrate 21. The second base substrate 21 has an upper surface 21a and a lower surface 21b that are opposite to each other. Furthermore, the second base substrate 21 has a second recess 211 with a bottom that opens onto the upper surface 21a and a third recess 212 with a bottom that opens onto the lower surface 21b. Therefore, the second base substrate 21 has an H-shaped cross-section. The recess 211 is composed of multiple recesses, including a recess 211a that opens onto the upper surface 21a and a recess 211b that opens onto the bottom surface of the recess 211a but has an opening smaller than that of the recess 211a. Similarly, the recess 212 is composed of multiple recesses, including a recess 212a that opens onto the lower surface 21b and a recess 212b that opens onto the bottom surface of the recess 212a but has an opening smaller than that of the recess 212a. Furthermore, the temperature-compensated quartz oscillator 3 is fixed to the bottom surface of the recess 211b via the heat insulation component 8, and the second circuit element 4 is fixed to the bottom surface of the recess 212b.

[0021] Furthermore, a plurality of internal terminals 241 are disposed on the bottom surface of recess 211a, a plurality of internal terminals 242 are disposed on the bottom surface of recess 212a, and a plurality of mounting terminals 243 are disposed on the lower surface 21b. These terminals 241, 242, and 243 are electrically connected via internal wiring (not shown) formed within the second base substrate 21. Each internal terminal 241 is electrically connected to the inner package 5 via bonding wire BW3, and each internal terminal 242 is electrically connected to the second circuit element 4 via bonding wire BW4. Moreover, the oscillator 1 is electrically connected to an external device (not shown) via the plurality of mounting terminals 243.

[0022] Furthermore, the outer package 2 has a second cover 22. The second cover 22 is engaged with the upper surface 21a of the second base substrate 21 by means of a coupling member 23, thereby closing the opening of the recess 211. By closing the opening of the recess 211 with the second cover 22 in this way, a hermetically sealed second storage space S2 is formed inside the outer package 2. Moreover, the temperature-compensated quartz oscillator 3 is stored in the second storage space S2.

[0023] The second storage space S2 is in a depressurized state, preferably closer to a vacuum. This improves the thermal insulation of the outer package 2, making the oscillator 1 less susceptible to external temperature influences. Furthermore, heat exchange between the temperature-compensated quartz oscillator 3 disposed within the second storage space S2 and the second circuit element 4 disposed outside the second storage space S2 can be suppressed, especially heat exchange caused by convection. Therefore, uneven heating of the temperature sensor 71 included in the first circuit element 7 and the vibrating element 6 due to the heat of the second circuit element 4 can be suppressed. In other words, temperature differences between the vibrating element 6 and the temperature sensor 71 due to the heat of the second circuit element 4 can be suppressed. Therefore, a high-precision oscillator 1 can be obtained.

[0024] However, the atmosphere of the second storage space S2 is not particularly limited. For example, it can be an atmosphere containing inert gases such as nitrogen, argon, or helium, or it can be atmospheric pressure or pressurized instead of a depressurized state. In addition, as described in the embodiments below, the second storage space S2 can be filled with a heat-insulating component 8.

[0025] In addition, although there are no particular limitations, the second base substrate 21 can be made of ceramic such as alumina, and the second cover 22 can be made of metal materials such as Kovar alloy.

[0026] like Figure 1 As shown, the temperature-compensated quartz oscillator 3 has an internal package 5, and an oscillating element 6 and a first circuit element 7 housed in the internal package 5.

[0027] Additionally, the inner package 5 includes a first base substrate 51. The first base substrate 51 has an upper surface 51a and a lower surface 51b that are in a front-to-back relationship. Furthermore, the first base substrate 51 has a first recess 511 with a bottom, which opens onto the lower surface 51b. The recess 511 is composed of multiple recesses, including: a recess 511a that opens onto the lower surface 51b; a recess 511b that opens onto the bottom surface of the recess 511a but has an opening smaller than that of the recess 511a; and a recess 511c that opens onto the bottom surface of the recess 511b but has an opening smaller than that of the recess 511b.

[0028] Furthermore, a first circuit element 7 is fixed to the bottom surface of recess 511c, and a vibrating element 6 is fixed to the bottom surface of recess 511a. With this configuration, the vibrating element 6 and the first circuit element 7 can be arranged overlapping along the Z-axis within the inner package 5. Therefore, they can be compactly housed within the inner package 5, enabling miniaturization of the temperature-compensated quartz oscillator 3. However, the arrangement of the vibrating element 6 is not limited to this; for example, it can also be fixed to the upper surface of the first circuit element 7. Additionally, the vibrating element 6 and the first circuit element 7 can be arranged side-by-side in the X-axis or Y-axis direction.

[0029] Furthermore, a plurality of internal terminals 541 are disposed on the bottom surface of the recess 511a, a plurality of internal terminals 542 are disposed on the bottom surface of the recess 511b, and a plurality of external terminals 543 are disposed on the upper surface 51a. These terminals 541, 542, and 543 are electrically connected via internal wiring (not shown) formed within the first base substrate 51. Additionally, the plurality of external terminals 543 are electrically connected to the internal terminals 241 of the second base substrate 21 via bonding wires BW3. By providing the external terminals 543 facing outwards from the inner package 5 in this manner, the electrical connection between the inner package 5 and the outer package 2 becomes easier.

[0030] Furthermore, since the conductive component that electrically connects the inner package 5 and the outer package 2 has high thermal conductivity, it readily functions as a heat transfer path between the inner package 5 and the outer package 2. Therefore, by using a thin, linear bonding wire BW3 as the aforementioned conductive component, heat transfer between the inner package 5 and the outer package 2 can be effectively suppressed. Consequently, external heat is less likely to be transferred to the inner package 5. Therefore, the vibrating element 6 is less susceptible to external heat, temperature changes in the vibrating element 6 can be suppressed, and the temperature difference between the vibrating element 6 and the temperature sensor 71 can be minimized.

[0031] Additionally, the inner package 5 has a first cover 52. The first cover 52 is engaged with the lower surface 51b of the first base substrate 51 by means of a coupling member 53, thereby closing the opening of the recess 511. By closing the opening of the recess 511 with the first cover 52 in this way, an airtight first storage space S1 is formed inside the inner package 5. Furthermore, the vibration element 6 and the first circuit element 7 are stored in this first storage space S1.

[0032] The first storage space S1 is in a depressurized state, preferably closer to a vacuum. This reduces the CI (crystal impedance) value of the vibrating element 6 and improves its oscillation characteristics. However, the atmosphere of the first storage space S1 is not particularly limited; for example, it can be atmospheric pressure or pressurized.

[0033] In addition, although there are no particular limitations, the first base substrate 51 can be made of ceramic such as alumina, and the first cover 52 can be made of metal materials such as Kovar alloy.

[0034] The inner enclosure 5 is configured such that the first cover 52 faces the bottom surface of the recess 211, i.e., the negative side in the Z-axis direction. The first cover 52 is fixed to the bottom surface of the recess 211 via a heat-insulating member 8. By positioning the heat-insulating member 8 between the inner enclosure 5 and the outer enclosure 2, external heat, particularly the heat from the second circuit element 4, is less likely to be transferred to the inner enclosure 5 via the outer enclosure 2. Therefore, the vibrating element 6 is less susceptible to external heat, effectively suppressing temperature differences between the vibrating element 6 and the temperature sensor 71 caused by external heat. Consequently, the temperature of the vibrating element 6 can be detected with higher accuracy by the temperature sensor 71, enabling excellent temperature compensation.

[0035] In particular, by fixing the first cover 52, which is not used to fix the vibration element 6 in the components constituting the inner package 5, to the outer package 2, the heat transfer path from the heat insulation component 8 to the vibration element 6 can be extended. Therefore, even if external heat is transferred to the inner package 5 via the heat insulation component 8, this heat is less likely to be transferred to the vibration element 6. As a result, the vibration element 6 is less susceptible to the effects of external heat, and the temperature difference between the vibration element 6 and the temperature sensor 71 caused by external heat can be more effectively suppressed. However, this is not a limitation; the first base plate 51 can also be fixed to the second base plate 21 via the heat insulation component 8.

[0036] The heat insulation component 8 is made of a material with a lower thermal conductivity than the first cover 52. There are no particular limitations on the heat insulation component 8; various resin materials can be used, with porous resin materials such as porous polyimide being particularly preferred. Besides resin materials, various glass materials, inorganic porous materials such as silica aerogel, etc., can also be used. Furthermore, the thermal conductivity of the heat insulation component 8 is not particularly limited, but is preferably 1.0 W / m·K or less. This results in a heat insulation component 8 with sufficiently low thermal conductivity.

[0037] Furthermore, the heat insulation component 8 has multiple columnar portions 81 arranged separately from each other, which are arranged in an island shape over the entire area of ​​the first cover 52. This allows the inner package 5 to be stably fixed to the outer package 2. Additionally, it reduces the contact area between the heat insulation component 8 and the outer package 2, making it less likely for external heat to be transferred to the inner package 5 via the heat insulation component 8. However, this is not a limitation; the heat insulation component 8 can also be arranged across the entire lower surface of the first cover 52. This increases the bonding area between the inner package 5 and the outer package 2, thereby increasing the adhesive strength. Consequently, the mechanical strength of the oscillator 1 is improved.

[0038] Furthermore, if the heat insulation component 8 has adhesive strength, the first cover 52 and the second base substrate 21 can be joined using the heat insulation component 8. On the other hand, if the heat insulation component 8 does not have adhesive strength, the heat insulation component 8 and the first cover 52, as well as the heat insulation component 8 and the second base substrate 21, can be joined using adhesives or other joining components. Additionally, the heat insulation component 8 may contain a gap material with sufficiently low thermal conductivity, such as silicone. This allows for control of the thickness of the heat insulation component 8, resulting in more reliable heat insulation performance.

[0039] Vibrating element 6 is an AT-cut quartz vibrating element. Due to its third-degree temperature characteristic, the AT-cut quartz vibrating element exhibits excellent frequency stability. For example... Figure 2 As shown, the vibrating element 6 has a rectangular quartz substrate 61 cut by AT cutting and electrodes disposed on the surface of the quartz substrate 61. The electrodes include: a first excitation electrode 621 disposed on the lower surface of the quartz substrate 61; and a second excitation electrode 631 disposed on the upper surface of the quartz substrate 61, facing the first excitation electrode 621 across the quartz substrate 61. Furthermore, the electrodes include: a first pad electrode 622 and a second pad electrode 632 arranged at the edge of the lower surface of the quartz substrate 61; a first lead-out electrode 623 electrically connecting the first excitation electrode 621 and the first pad electrode 622; and a second lead-out electrode 633 electrically connecting the second excitation electrode 631 and the second pad electrode 632.

[0040] However, the structure of the vibrating element 6 is not particularly limited. For example, the top view shape of the quartz substrate 61 is not limited to a rectangle, but can also be circular. In addition, as the vibrating element 6, besides AT-cut quartz vibrating elements, it can also be SC-cut quartz vibrating elements, BT-cut quartz vibrating elements, tuning fork-type quartz vibrating elements, surface acoustic wave resonators, other piezoelectric vibrating elements, MEMS (Micro Electro Mechanical Systems) resonant elements, etc.

[0041] Alternatively, lithium niobate (LiNbO3), lithium tantalate (LiTaO3), lead zirconate titanate (PZT), lithium tetraborate (Li2B4O7), and lanthanum gallium silicate (La3Ga5SiO3) can be used instead of quartz substrate 61. 14 Potassium niobate (KNbO3), gallium phosphate (GaPO4), gallium arsenide (GaAs), aluminum nitride (AlN), zinc oxide (ZnO, Zn2O3), barium titanate (BaTiO3), lead titanate (PbPO3), potassium sodium niobate ((K,Na)NbO3), bismuth ferrite (BiFeO3), sodium niobate (NaNbO3), bismuth titanate (Bi4Ti3O3) 12 ), sodium bismuth titanate (Na) 0.5 Bi 0.5Various piezoelectric substrates such as TiO3 can be used, for example, substrates other than piezoelectric substrates such as silicon substrates can also be used.

[0042] Such a vibrating element 6 is joined at one end to the bottom surface of the recess 511a by means of a pair of conductive bonding members B. Furthermore, the first pad electrode 622 and the second pad electrode 632 are electrically connected to the internal terminal 541 via a pair of bonding members B, respectively. The bonding members B are not particularly limited; for example, conductive bonding members such as metal bumps, solder, brazing filler metal, metal paste, or conductive resin adhesives can be used.

[0043] The first circuit element 7 is electrically connected to the internal terminal 542 via bonding wire BW2. Furthermore, the first circuit element 7 includes a temperature sensor 71 and an oscillation circuit 72. The oscillation circuit 72 functions to oscillate the vibrating element 6, generating an oscillation signal after temperature compensation based on the temperature detected by the temperature sensor 71. Specifically, the oscillation circuit 72 includes: an oscillation circuit section 721 electrically connected to the vibrating element 6, which amplifies the output signal of the vibrating element 6 and feeds the amplified signal back to the vibrating element 6, thereby causing the vibrating element 6 to oscillate; and a temperature compensation circuit section 722, which performs temperature compensation based on the temperature information output from the temperature sensor 71, so that the frequency variation of the output signal is less than the frequency-temperature characteristics of the vibrating element 6 itself.

[0044] As the oscillation circuit 72, for example, a Pierce oscillation circuit, an Inverter-type oscillation circuit, a Colpitts oscillation circuit, a Hartley oscillation circuit, or other oscillation circuits can be used. Furthermore, as the temperature compensation circuit 722 of the oscillation circuit 72, the oscillation frequency of the oscillation circuit 721 can be adjusted, for example, by adjusting the capacitance of the variable capacitor circuit connected to the oscillation circuit 721, or by adjusting the frequency of the output signal of the oscillation circuit 721 through a PLL circuit or a direct digital synthesizer circuit.

[0045] By housing the temperature sensor 71 and the vibration element 6 together in the inner package 5, the temperature sensor 71 can be positioned in the same space as and near the vibration element 6. Therefore, the temperature of the vibration element 6 can be detected with higher accuracy by the temperature sensor 71, and the temperature compensation of the oscillation circuit 72 is more accurate.

[0046] In this embodiment, the temperature sensor 71 is composed of an IC temperature sensor and is built into the first circuit element 7, which is a single integrated circuit. However, the present invention is not limited to this. That is, the first circuit element 7 may also be composed of an integrated circuit with a built-in oscillation circuit 72 and the temperature sensor 71, i.e., discrete components. In this case, the temperature sensor 71 may be composed of, for example, a thermistor or a thermocouple. Furthermore, the arrangement of the temperature sensor 71 is not particularly limited as long as it can detect the temperature of the vibration element 6 within the first storage space S1. For example, it may be arranged on the upper surface of the first base substrate 51 and the first circuit element 7.

[0047] like Figure 1 As shown, the second circuit element 4 is disposed within the recess 212 of the second base substrate 21 and fixed to the bottom surface of the recess 212. That is, the second circuit element 4 is located outside the second storage space S2. In addition, the second circuit element 4 is disposed separately from the inner package 5. As a result, the heat of the second circuit element 4 is not easily transferred to the inner package 5 located in the second storage space S2. Therefore, the vibration element 6 is not easily affected by the heat of the second circuit element 4, the temperature change of the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized. Furthermore, since the temperature-compensated quartz oscillator 3 and the second circuit element 4 can be arranged to overlap in the Z-axis direction, the expansion of the oscillator 1 in the X-axis and Y-axis directions is suppressed, and the miniaturization of the oscillator 1 is achieved.

[0048] like Figure 3 As shown, this second circuit element 4 includes: a fractional-division type PLL circuit 40 (phase synchronization circuit) as a frequency control circuit, which controls the frequency of the oscillation signal output from the oscillation circuit 72 and further corrects the residual frequency-temperature characteristics in the oscillation signal output from the temperature-compensated quartz oscillator 3; a storage unit that stores a temperature correction table 481; and an output circuit 49. In this embodiment, the PLL circuit 40, the storage unit 48, and the output circuit 49 are configured as a single-chip circuit element, but they may also be configured as multiple-chip circuit elements, or a portion of them may be configured as discrete components.

[0049] The PLL circuit 40 includes a phase comparator 41, a charge pump 42, a low-pass filter 43, a voltage-controlled oscillator circuit 44, and a frequency divider circuit 45. The phase comparator 41 compares the phase difference between the oscillation signal output from the oscillation circuit 72 and the clock signal output from the frequency divider circuit 45, outputting the comparison result as a pulse voltage. The charge pump 42 converts the pulse voltage output from the phase comparator 41 into current, and the low-pass filter 43 smooths and converts the current output from the charge pump 42.

[0050] The voltage-controlled oscillator circuit 44 uses the output voltage of the low-pass filter 43 as the control voltage, and outputs a signal whose frequency varies according to the control voltage. Furthermore, the voltage-controlled oscillator circuit 44 in this embodiment is an LC oscillator circuit composed of inductive elements such as coils and capacitive elements such as capacitors, but it is not limited to this; for example, an oscillator circuit utilizing a piezoelectric oscillator such as a quartz oscillator can also be used. The frequency divider circuit 45 outputs a clock signal after fractionally dividing the clock signal output by the voltage-controlled oscillator circuit 44 according to the frequency division ratio determined by the output signal of the temperature sensor 71 and the temperature correction table 481. Furthermore, the frequency division ratio of the frequency divider circuit 45 is not limited to the structure determined by the temperature correction table 481. For example, it can be determined by polynomial operations or by neural network operations based on a learned model that has undergone machine learning.

[0051] The output circuit 49 receives the clock signal output from the PLL circuit 40 and generates an oscillation signal whose amplitude is adjusted to the desired level. The oscillation signal generated by the output circuit 49 is output to the outside of the oscillator 1 via the mounting terminal 243 of the oscillator 1.

[0052] In this way, the PLL circuit 40 further corrects the residual frequency-temperature characteristics in the oscillation signal output by the temperature-compensated quartz oscillator 3, thereby obtaining an oscillator 1 with smaller temperature-induced frequency deviation. Furthermore, the PLL circuit 40 is not particularly limited; for example, an integer division type PLL circuit can be provided between the oscillation circuit 72 and the phase comparator 41 to divide the oscillation signal output by the oscillation circuit 72 according to an integer division ratio. The PLL circuit 40 is not limited to a circuit that further compensates for the temperature of the output signal of the temperature-compensated quartz oscillator 3. For example, to obtain a desired frequency signal, the PLL circuit 40 can also be configured to multiply the output frequency of the temperature-compensated quartz oscillator 3 by a fixed value.

[0053] A heat-insulating element 8 is positioned between the second circuit element 4 and the temperature-compensated quartz oscillator 3. This prevents heat from the second circuit element 4 from easily transferring to the temperature-compensated quartz oscillator 3, effectively suppressing temperature differences between the vibrating element 6 and the temperature sensor 71 caused by the heat of the second circuit element 4. Therefore, the temperature of the vibrating element 6 can be detected more accurately by the temperature sensor 71. In particular, in this embodiment, the second circuit element 4 has a PLL circuit 40, but this PLL circuit 40 consumes a large amount of power and is prone to overheating. Therefore, by installing the heat-insulating element 8 between the second circuit element 4 and the temperature-compensated quartz oscillator 3, the aforementioned effects can be achieved more significantly. Furthermore, the second circuit element 4 also operates based on the temperature information signal output by the temperature sensor 71, and therefore is less affected by its own heat generation.

[0054] In addition to the second circuit element 4, discrete components (not shown) or other electronic components may also be fixed in the recess 212. There are no particular limitations on the discrete components; examples include a bypass capacitor that removes noise from the power supply voltage supplied via mounting terminal 243 to provide a stable power supply voltage to the first circuit element 7, and a bypass capacitor that removes noise from the output signal of the temperature sensor 71 to provide a more accurate output signal to the PLL circuit 40. Other components that may be used include thermistors, resistors, diodes, etc.

[0055] The oscillator 1 has been described above. As described above, this oscillator 1 includes: an outer package 2; an inner package 5 housed in the outer package 2 and fixed to the outer package 2 via a heat insulation member 8; a vibration element 6 housed in the inner package 5; a temperature sensor 71; a first circuit element 7 including an oscillation circuit 72, which causes the vibration element 6 to oscillate and generates an oscillation signal after temperature compensation based on the temperature sensor 71, the first circuit element 7 being housed in the inner package 5; and a second circuit element 4 fixed to the outer package 2, which includes a PLL circuit 40 as a frequency control circuit for controlling the frequency of the oscillation signal.

[0056] With this structure, since the heat insulation component 8 is located between the inner package 5 and the outer package 2, external heat, especially the heat of the second circuit element 4, is not easily transferred to the inner package 5 via the outer package 2. Therefore, the vibrating element 6 is less susceptible to external heat, and the temperature difference between the vibrating element 6 and the temperature sensor 71 caused by external heat can be effectively suppressed. Consequently, the temperature of the vibrating element 6 can be detected with higher accuracy by the temperature sensor 71, and excellent temperature compensation can be achieved by the oscillation circuit 72. Furthermore, by setting the frequency control circuit as a PLL circuit 40, an oscillation signal with small frequency deviation can be output. Therefore, it becomes an oscillator 1 capable of outputting a high-precision frequency signal.

[0057] Furthermore, as described above, the second circuit element 4 is disposed separately from the inner package 5. Therefore, heat from the second circuit element 4 is less likely to be transferred to the inner package 5. Consequently, the vibration element 6 is less affected by the heat of the second circuit element 4, temperature changes in the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized.

[0058] Furthermore, as described above, the oscillator 1 has a conductive lead, namely a bonding wire BW3, that electrically connects the outer package 2 and the inner package 5. This conductive component, which electrically connects the inner package 5 and the outer package 2, has high thermal conductivity and readily functions as a heat transfer path between the inner package 5 and the outer package 2. Therefore, by using the elongated, linear bonding wire BW3 as the aforementioned conductive component, heat transfer between the inner package 5 and the outer package 2 can be effectively suppressed. Consequently, external heat is less likely to be transferred to the inner package 5. Therefore, the vibration element 6 is less susceptible to external heat, temperature changes in the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized.

[0059] Furthermore, as described above, the inner package 5 includes: a first base substrate 51 having a first recess 511 for housing the vibration element 6, the temperature sensor 71, and the first circuit element 7; and a first cover 52 that engages with the first base substrate 51 to close the opening of the recess 511. The vibration element 6 is fixed to the first base substrate 51, and the first cover 52 is fixed to the outer package 2 via the heat insulation member 8. By fixing the first cover 52 (which does not hold the vibration element 6) in the inner package 5 to the outer package 2 in this way, the heat transfer path from the heat insulation member 8 to the vibration element 6 can be extended. Therefore, even if heat is transferred from the outer package 2 to the inner package 5 via the heat insulation member 8, this heat is less likely to be transferred to the vibration element 6. Therefore, the vibration element 6 is less susceptible to external heat, temperature changes in the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized.

[0060] Furthermore, as described above, the inner package 5 has an external terminal 543 disposed on the upper surface 51a of the first base substrate 51 opposite to the lower surface 51b to which the first cover 52 is joined. This facilitates electrical connection between the inner package 5 and the outer package 2.

[0061] Furthermore, as described above, the outer package 2 has: a recess 211, which is a second recess for receiving the inner package 5; a recess 212, which is a third recess that opens on the side opposite to the opening of the recess 211, i.e., the lower surface 21b, and receives the second circuit element 4; and a second cover 22, which is joined to the second base substrate 21 in a manner that closes the opening of the recess 211. With this structure, the second circuit element 4 can be positioned outside the second receiving space S2, making it difficult for the heat of the second circuit element 4 to be transferred to the inner package 5. Therefore, the vibration element 6 is less susceptible to the heat of the second circuit element 4, temperature changes of the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized. Furthermore, since the inner package 5 and the second circuit element 4 can be arranged to overlap in the Z-axis direction, the expansion of the oscillator 1 in the X-axis and Y-axis directions can be suppressed, enabling miniaturization of the oscillator 1.

[0062] Furthermore, as described above, the second storage space S2, which serves as the space for accommodating the inner package 5 within the outer package 2, is in a depressurized state. This provides excellent thermal insulation, preventing heat from the outside of the oscillator 1 from easily transferring to the inner package 5. Consequently, temperature changes in the vibration element 6 can be suppressed, and the temperature difference between the vibration element 6 and the temperature sensor 71 can be minimized.

[0063] <Second Implementation Method>

[0064] Figure 4 This is a cross-sectional view showing the oscillator of the second embodiment.

[0065] This embodiment is identical to the first embodiment described above, except for the structure of the outer encapsulation 2. In the following description, this embodiment will be described primarily for its differences from the aforementioned embodiments; identical details will be omitted. Figure 4 In this document, structures that are the same as those in the aforementioned embodiments are marked with the same reference numerals.

[0066] like Figure 4 As shown, in the oscillator 1 of this embodiment, the second base substrate 21 has a second recess, namely recess 211, with an opening on its upper surface 21a. Furthermore, the second cover 22 is engaged with the upper surface 21a of the second base substrate 21 to close the recess 211. By closing the opening of the recess 211 with the second cover 22, a hermetically sealed second storage space S2 is formed inside the outer package 2. The temperature-compensated quartz oscillator 3 and the second circuit element 4 are housed in the second storage space S2.

[0067] Furthermore, the recess 211 is composed of multiple recesses, including: a recess 211a that opens onto the upper surface 21a; and recesses 211b and 211c that open onto the bottom surface of the recess 211a, with the opening being smaller than that of the recess 211a. Additionally, recesses 211b and 211c are formed side-by-side in the X-axis direction, and the depth of recess 211b is greater than the depth of recess 211c. Therefore, the bottom surface of recess 211b is located lower than the bottom surface of recess 211c. Furthermore, the thickness of the portion of the second base substrate 21 that overlaps with recess 211b is smaller than the thickness of the portion that overlaps with recess 211c.

[0068] Furthermore, a second circuit element 4 is fixed to the bottom surface of recess 211c, and a temperature-compensated quartz oscillator 3 is fixed to the bottom surface of recess 211b. In addition, when viewed from above, the second circuit element 4 and the temperature-compensated quartz oscillator 3 are arranged side-by-side in the X-axis direction, without overlapping in the Z-axis direction. With this arrangement, the second circuit element 4 and the temperature-compensated quartz oscillator 3 are housed together within recess 211. Therefore, for example, compared to the structure described in the first embodiment where the second circuit element 4 and the temperature-compensated quartz oscillator 3 are housed in their respective recesses, the structure of the oscillator 1 becomes simpler. Furthermore, since the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be arranged side-by-side in the X-axis direction without overlapping in the Z-axis direction, a thinner outer package 2 can be achieved.

[0069] As described above, the outer package 2 includes: a second base substrate 21 having a recess 211, which is a second recess for receiving the inner package 5 and the second circuit element 4; and a second cover 22, which is engaged with the second base substrate 21 to close the opening of the recess 211. Therefore, the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be simultaneously received in the recess 211. For example, compared with the structure in which the second circuit element 4 and the temperature-compensated quartz oscillator 3 are received in their respective recesses as in the first embodiment described above, the structure of the oscillator 1 becomes simpler.

[0070] Furthermore, as mentioned earlier, the inner package 5 and the second circuit element 4 are arranged side-by-side when viewed from above. Therefore, the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be arranged in the X-axis direction without overlapping in the Z-axis direction. Thus, a thinner outer package 2 can be achieved.

[0071] According to the second embodiment described above, the same effects as the first embodiment described above can also be achieved.

[0072] <Third Implementation Method>

[0073] Figure 5 This is a cross-sectional view showing the oscillator of the third embodiment.

[0074] This embodiment is identical to the first embodiment described above, except for the structure of the outer encapsulation 2. In the following description, this embodiment will be described primarily for its differences from the aforementioned embodiments; identical details will be omitted. Figure 5 In this document, structures that are the same as those in the aforementioned embodiments are marked with the same reference numerals.

[0075] like Figure 5 As shown, in the oscillator 1 of this embodiment, the second base substrate 21 has a second recess, namely recess 211, with an opening on its upper surface 21a. Furthermore, the second cover 22 is engaged with the upper surface 21a of the second base substrate 21 to close the recess 211. By closing the opening of the recess 211 with the second cover 22, a hermetically sealed second storage space S2 is formed inside the outer package 2. The temperature-compensated quartz oscillator 3 and the second circuit element 4 are housed in the second storage space S2.

[0076] In addition, the recess 211 is composed of a plurality of recesses, including: a recess 211a that opens on the upper surface 21a; a recess 211b that opens on the bottom surface of the recess 211a and the opening is smaller than that of the recess 211a; a recess 211c that opens on the bottom surface of the recess 211b and the opening is smaller than that of the recess 211b; and a recess 211d that opens on the bottom surface of the recess 211c and the opening is smaller than that of the recess 211c.

[0077] Furthermore, a second circuit element 4 is fixed to the bottom surface of recess 211b in a manner that covers part or all of the opening of recess 211c, and a temperature-compensated quartz oscillator 3 is fixed to the bottom surface of recess 211d. With this configuration, the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be overlapped in the Z-axis direction within the outer package 2. Therefore, the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be compactly housed within the outer package 2, enabling miniaturization of the oscillator 1.

[0078] As described above, the outer package 2 includes: a second base substrate 21 having a second recess 211 for receiving the inner package 5 and the second circuit element 4; and a second cover 22 that engages with the second base substrate 21 to close the opening of the recess 211. Thus, the second circuit element 4 and the temperature-compensated quartz oscillator 3 can be received within a single recess 211. For example, compared to the structure in the first embodiment described above, where the second circuit element 4 and the temperature-compensated quartz oscillator 3 are received in their respective recesses, the structure of the oscillator 1 becomes simpler.

[0079] Furthermore, as described above, the inner package 5 and the second circuit element 4 are configured to overlap when viewed from above. This enables the miniaturization of the oscillator 1.

[0080] According to the third embodiment described above, the same effect as the first embodiment described above can also be achieved.

[0081] <Fourth Implementation>

[0082] Figure 6 This is a cross-sectional view showing the oscillator of the fourth embodiment.

[0083] This embodiment is identical to the first embodiment described above, except for the configuration of the heat insulation component 8. In the following description, this embodiment will be described primarily for its differences from the aforementioned embodiments, and descriptions of identical items will be omitted. Figure 6 In this document, structures that are the same as those in the aforementioned embodiments are marked with the same reference numerals.

[0084] like Figure 6 As shown, in the oscillator 1 of this embodiment, the heat insulation member 8 fills the space in the outer package 2 that houses the inner package 5, namely the second housing space S2. That is, the heat insulation member 8 is disposed in the second housing space S2 substantially without gaps. Moreover, the entire circumference of the inner package 5 is covered by the heat insulation member 8. As a result, the inner package 5 can be more firmly fixed to the outer package 2, and the mechanical strength of the oscillator 1 is improved.

[0085] According to the fourth embodiment described above, the same effect as the first embodiment described above can also be achieved.

[0086] The oscillator of the present invention has been described above based on the illustrated embodiments, but the present invention is not limited thereto, and the structure of each part can be replaced with any structure having the same function. Furthermore, other arbitrary components can be added to the present invention. Additionally, the above embodiments can be appropriately combined.

Claims

1. An oscillator, characterized in that, It has the following characteristics: External encapsulation; The inner packaging is housed within the outer packaging and is fixed to the outer packaging via a heat-insulating component; The vibrating element is housed within the inner enclosure. A temperature sensor, which is housed in the inner package; The first circuit element includes an oscillation circuit that causes the vibrating element to oscillate, generating an oscillation signal after temperature compensation based on the temperature sensor, and the first circuit element is housed in the inner package. as well as The second circuit element, fixed to the outer package, includes a frequency control circuit that controls the frequency of the oscillation signal. The outer packaging includes: The second base substrate has a second recess that accommodates the inner package and the second circuit element; as well as The second cover engages with the second base plate in a manner that closes the opening of the second recess. The inner package and the second circuit element are arranged side by side when viewed from above.

2. An oscillator, characterized in that, It has the following characteristics: External encapsulation; The inner packaging is housed within the outer packaging and is fixed to the outer packaging via a heat-insulating component; The vibrating element is housed within the inner enclosure. A temperature sensor, which is housed in the inner package; The first circuit element includes an oscillation circuit that causes the vibrating element to oscillate, generating an oscillation signal after temperature compensation based on the temperature sensor, and the first circuit element is housed in the inner package. as well as The second circuit element, fixed to the outer package, includes a frequency control circuit that controls the frequency of the oscillation signal. The outer packaging includes: The second base substrate has a second recess and a third recess, the second recess receiving the inner package, and the third recess opening on the side opposite to the opening of the second recess to receive the second circuit element. as well as The second cover engages with the second base plate in a manner that closes the opening of the second recess. The second base substrate having the second recess and the third recess is made of ceramic.

3. The oscillator according to claim 2, wherein, The inner package and the second circuit element are arranged side by side when viewed from above.

4. The oscillator according to any one of claims 1 to 3, wherein, The inner package and the second circuit element are configured separately.

5. The oscillator according to any one of claims 1 to 3, wherein, The oscillator has conductive leads that electrically connect the outer package and the inner package.

6. The oscillator according to any one of claims 1 to 3, wherein, The inner encapsulation has: A first base plate having a first recess for receiving the vibration element, the temperature sensor, and the first circuit element; and The first cover engages with the first base plate in a manner that closes the opening of the first recess. The vibration element is fixed to the first base plate. The first cover is fixed to the outer enclosure through the heat insulation component.

7. The oscillator according to claim 6, wherein, The inner package has an external terminal disposed on the side of the first base substrate opposite to the side to which the first cover is joined.

8. The oscillator according to any one of claims 1 to 3, wherein, The space encapsulated on the outer side, which houses the inner side, is in a depressurized state.

9. The oscillator according to any one of claims 1 to 3, wherein, The heat insulation component fills the space encapsulated on the outer side that accommodates the inner side encapsulation.

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