Sensor device and portable apparatus

Abstract

To reduce the impact of communication noise on the output of a sensor device.SOLUTION: A sensor device (102) includes a first substrate (1) having a communication line (LN1), a second substrate (2) having a sensor element (6, C1), a signal processing unit (7) configured to process the output of the sensor element, an inversion unit (8) configured to generate an inverted signal of a communication signal transmitted by the communication line, and a capacitance (C2) provided between an output end of the inversion unit and the second substrate.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The invention disclosed herein relates to a sensor device and a portable device. [Background technology]

[0002] In recent years, MEMS sensor elements have been manufactured using MEMS (Micro Electro Mechanical Systems) technology that is manufactured using semiconductor manufacturing processes (see, for example, Patent Document 1). The output signal of the MEMS sensor element is very small. In addition, the output signal of sensor elements other than the MEMS sensor element is often also very small. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2023-020325

[0004] [overview] When a sensor device including a sensor element communicates with the outside, communication noise occurs, and the communication noise affects the output signal of the sensor element and, in turn, the output of the sensor device (an amplified signal of the output signal of the sensor element) due to coupling.

[0005] The sensor device disclosed in this specification comprises a first substrate having a communication line, a second substrate having a sensor element, a signal processing unit configured to process the output of the sensor element, an inversion unit configured to generate an inverted signal of a communication signal transmitted by the communication line, and a capacitance provided between the output end of the inversion unit and the second substrate.

[0006] The portable device disclosed in this specification includes the sensor device having the above-described configuration. [Brief description of the drawings]

[0007] [Figure 1]FIG. 1 is a diagram illustrating a schematic cross-sectional structure of a sensor device according to a reference example. [Diagram 2] FIG. 2 is a schematic circuit diagram of the sensor device shown in FIG. [Diagram 3] FIG. 3 is a diagram showing an output of the sensor device shown in FIG. 1 when no communication is being performed. [Figure 4] FIG. 4 is a diagram showing an output of the sensor device shown in FIG. 1 during communication. [Diagram 5] FIG. 5 is a diagram showing the result of frequency analysis of the output of the sensor device shown in FIG. 1 when no communication is being performed. [Figure 6] FIG. 6 is a diagram showing a result of frequency analysis of the output of the sensor device shown in FIG. 1 during communication. [Figure 7] FIG. 7 is a waveform diagram of the potentials of the communication line, the second substrate, and the charge input line. [Figure 8] FIG. 8 is a schematic circuit diagram of the sensor device according to the embodiment. [Figure 9] FIG. 9 is a top view diagrammatically illustrating a first configuration example of the sensor device according to the embodiment. [Figure 10] FIG. 10 is a top view illustrating a second configuration example of the sensor device according to the embodiment. [Figure 11] FIG. 11 is a diagram showing the output of the sensor device shown in FIG. 10 during communication. [Figure 12] FIG. 12 is a diagram showing the result of frequency analysis of the output of the sensor device shown in FIG. 10 during communication. [Figure 13] FIG. 13 is a block diagram illustrating an example of the configuration of a smartphone.

[0008] [Detailed Description] <Sensor device according to reference example> 1 is a diagram showing a schematic cross-sectional structure of a sensor device 101 according to a reference example. The sensor device 101 is an acceleration sensor device that detects acceleration. The sensor device 101 includes a first substrate 1, a second substrate 2, a cover portion 3, a semiconductor chip 4, a resin 5, a first bonding wire W1, and a second bonding wire W2.

[0009] The second substrate 2 is disposed on the upper surface of the first substrate 1. A part of the upper surface of the second substrate 2 is covered by a lid portion 3. A sensor element 6 is provided on the portion of the second substrate 2 covered by the lid portion 3.

[0010] The sensor element 6 is a capacitance type acceleration sensor element using MEMS (Micro Electro Mechanical System) technology. The sensor element 6 has a fixed electrode, a movable electrode, and a spring, which are made of, for example, silicon. When no acceleration is applied to the sensor element 6, the distance between the fixed electrode and the movable electrode does not change. On the other hand, when acceleration is applied to the sensor element 6, the movable electrode is displaced relative to the fixed electrode, and the capacitance between the fixed electrode and the movable electrode changes. In other words, the capacitance of the sensor element 6 changes according to the acceleration applied to the sensor element 6.

[0011] The semiconductor chip 4 is disposed on the upper surface of the lid 3. The first bonding wire W1 is a connection line that electrically connects a connection portion of the first substrate 1 to the first bonding wire W1 and a connection portion of the semiconductor chip 4 to the first bonding wire W1. The second bonding wire W2 is a connection line that electrically connects a connection portion of the second substrate 2 to the second bonding wire W2 and a connection portion of the semiconductor chip 4 to the second bonding wire W2. Note that, although only one each of the first bonding wire W1 and the second bonding wire W2 is illustrated in FIG. 1, there may be a plurality of first bonding wires W1 and a plurality of second bonding wires W2.

[0012] The second substrate 2, the lid portion 3, the semiconductor chip 4, the first bonding wires W1, and the second bonding wires W2 are sealed by the resin 5 and the upper surface of the first substrate 1.

[0013] Fig. 2 is a schematic circuit diagram of the sensor device 101 shown in Fig. 1. A communication terminal T1 for inputting and outputting a communication signal to and from the outside is an end of a communication line LN1. The communication signal transmitted by the communication line LN1 is, for example, a serial communication signal such as an SPI (Serial Peripheral Interface) communication signal or an I2C communication signal. The communication terminal T1 and the communication line LN1 are disposed on a first substrate 1. A first parasitic capacitance PC1 is formed between the communication line LN1 and a second substrate 2.

[0014] The sensor drive line LN2 is disposed on the second substrate 2 and the semiconductor chip 4. The charge input line LN3 is disposed on the second substrate 2 and the semiconductor chip 4. The sensing capacitance C1 constituted by the sensor element 6 is disposed on the second substrate 2.

[0015] A drive circuit (not shown) arranged on the semiconductor chip 4 outputs a drive signal. The drive signal is transmitted through the sensor drive line LN2 and reaches the sensing capacitance C1. During driving, the sensing capacitance C1 outputs a charge according to acceleration. The charge output from the sensing capacitance C1 is transmitted through the charge input line LN3 and reaches the CV converter 7 arranged on the semiconductor chip 4. The CV converter 7 converts the received charge into a voltage and outputs it. In other words, the CV converter 7 is an example of a signal processing unit configured to process the output of the sensor element 6.

[0016] A second parasitic capacitance PC2 is formed between the second substrate 2 and the sensor drive line LN2. A third parasitic capacitance PC3 is formed between the second substrate 2 and the charge input line LN3.

[0017] The first to third parasitic capacitances PC1 to PC3 couple the communication noise to the sensing capacitance C1.

[0018] Fig. 3 is a diagram showing the output of the sensor device 101 when it is not communicating. On the other hand, Fig. 4 is a diagram showing the output of the sensor device 101 when it is communicating. As is clear from a comparison between Fig. 3 and Fig. 4, when the sensor device 101 is communicating, the noise contained in the output of the sensor device 101 increases due to the influence of communication noise, compared to when the sensor device 101 is not communicating.

[0019] Fig. 5 is a diagram showing the frequency analysis result of the output of the sensor device 101 when it is not communicating. On the other hand, Fig. 6 is a diagram showing the frequency analysis result of the output of the sensor device 101 when it is communicating. As is clear from a comparison between Fig. 5 and Fig. 6, a frequency peak that did not appear when the sensor device 101 was not communicating appears when the sensor device 101 is communicating.

[0020] FIG. 7 is a waveform diagram of the potentials of the communication line LN1, the second substrate 2, and the charge input line LN3. When the sensor device 101 is performing communication, if the potential of the communication line LN1 changes due to a communication signal, the potential of the second substrate 2 coupled to the communication line LN1 by the first parasitic capacitance PC1 also changes (see FIG. 7). The second substrate 2 is coupled to the sensor drive line LN2 by the second parasitic capacitance PC2 and is coupled to the charge input line LN3 by the third parasitic capacitance PC3. Therefore, if the potential of the second substrate 2 changes, the potential of the charge input line LN3 also changes (see FIG. 7). In this way, the communication signal itself becomes communication noise, and the noise included in the output of the sensor device 101 increases due to the influence of the communication noise. The behavior of the potential of the communication line LN1 differs depending on the content of communication, and the amount of noise included in the output of the sensor device 101 changes depending on the content of communication.

[0021] <Sensor device according to embodiment> 8 is a schematic circuit diagram of a sensor device 102 according to an embodiment. The sensor device 102 is an acceleration sensor device that detects acceleration, similar to the sensor device 101. Note that a diagram showing a schematic cross-sectional structure of the sensor device 102 is similar to a diagram showing a schematic cross-sectional structure of the sensor device 101.

[0022] In the schematic circuit diagram of the sensor device 102, an inverter 8 and a capacitor C2 are added to the schematic circuit diagram of the sensor device 101. The inverter 8 generates an inverted signal of the communication signal transmitted by the communication line LN1. The capacitor C2 is provided between the output terminal of the inverter 8 and the second substrate 2.

[0023] The inverter 8 is mounted on the semiconductor chip 4 together with the CV converter 7. Since the inverter 8 and the CV converter 7 are circuits that process signals, they can easily be mounted on the same semiconductor chip 4. Note that the inverter 8 may be mounted on a chip different from the chip on which the CV converter 7 is mounted.

[0024] In the sensor device 102, the capacitance C2 injects into the second substrate 2 charges that are opposite in phase to the charges that the first parasitic capacitance PC1 injects into the second substrate 2. This allows the capacitance C2 to cancel the effect on the output of the sensor device 102 caused by the first parasitic capacitance PC1 injecting charges into the second substrate 2, by injecting charges of opposite phase into the second substrate 2. Therefore, the sensor device 102 can reduce the effect of communication noise on the output of the sensor device 102.

[0025] It is preferable that the capacitance value of the capacitance C2 is substantially the same as the capacitance value of the first parasitic capacitance PC1. By making the capacitance value of the capacitance C2 substantially the same as the capacitance value of the first parasitic capacitance PC1, the effect of reducing the influence of communication noise on the output of the sensor device 102 can be enhanced.

[0026] <First configuration example of the sensor device according to the embodiment> 9 is a top view diagrammatically illustrating a first configuration example of the sensor device 102. In this configuration example, the capacitor C2 is mounted on the semiconductor chip 4 together with the inverter 8. The first bonding wire W1 electrically connects the communication terminal T1 and the input terminal of the inverter 8.

[0027] The output terminal of the inverter 8 is connected to a first terminal of the capacitor C2. The second terminal of the capacitor C2 is connected to the second substrate 2 via a second bonding wire W2.

[0028] It is preferable that the capacitance value of the capacitor C2 is adjustable. For example, the capacitor C2 may include a plurality of capacitors and a plurality of trimming elements. By adjusting the capacitance value of the capacitor C2, the capacitance value of the capacitor C2 can be made closer to the capacitance value of the first parasitic capacitance PC1.

[0029] <Second configuration example of the sensor device according to the embodiment> 10 is a top view diagrammatically illustrating a second configuration example of the sensor device 102. In this configuration example, the first substrate 1 has a dummy wiring DMY1. A first bonding wire W1_1 electrically connects the communication terminal T1 and an input terminal of the inverter 8. An output terminal of the inverter 8 is connected to the dummy wiring DMY1 via another first bonding wire W1_2.

[0030] In this configuration example, the parasitic capacitance formed between the dummy wiring DMY1 and the second substrate 2 is a capacitance C2 (see FIG. 8). It is preferable that the shape and arrangement of the dummy wiring DMY1 are designed so that the capacitance value of the parasitic capacitance formed between the dummy wiring DMY1 and the second substrate 2 is approximately equal to the capacitance value of the first parasitic capacitance PC1.

[0031] Fig. 11 is a diagram showing an output of the sensor device 102 according to this configuration example when communicating. Fig. 12 is a diagram showing a frequency analysis result of the output of the sensor device 102 according to this configuration example when communicating.

[0032] As is clear from a comparison between Figures 4 and 11 and a comparison between Figures 6 and 12, compared to the sensor device 101, the effect of communication noise on the output of the sensor device 102 is reduced more than the effect of communication noise on the output of the sensor device 101.

[0033] <Application Examples> Here, an example in which the sensor device 102 is applied to a smartphone will be described. Note that a smartphone is an example of a portable device. Naturally, the sensor device 102 may be applied to a portable device other than a smartphone. Examples of portable devices other than a smartphone include a wearable watch and a wearable camera.

[0034] 13 is a block diagram showing an example of the configuration of a smartphone 200. The smartphone 200 includes a communication unit 201, a camera unit 202, a display unit 203, an audio input / output unit 204, an acceleration sensor 205, an operation unit 206, a storage unit 207, and a control unit 208.

[0035] The communication unit 201 performs wireless communication with a base station in a mobile communication network. This wireless communication is used to send and receive audio data, video data, e-mail data, and the like, and to receive Web data, streaming data, and the like.

[0036] The camera unit 202 captures electronic images using an imaging element such as a CMOS (Complementary Metal-Oxide-Semiconductor) image sensor, and can compress the captured images in, for example, JPEG (Joint Photographic Experts Group) format and store the compressed data in the memory unit 207.

[0037] The display unit 203 is, for example, a liquid crystal display device or an organic EL (Electro Luminescence) display device. The display unit 203 displays various images. The audio input / output unit 204 includes a microphone that collects input ambient sound and converts it into an electrical signal, and a speaker that converts the input audio signal into sound and outputs it to the outside.

[0038] The acceleration sensor 205 is a motion sensor that detects the movement of the person carrying the smartphone 200, and the above-mentioned sensor device 102 can be used.

[0039] The operation unit 206 includes keys arranged on the housing of the smartphone 200 for various operations such as power operations and volume operations, a touch panel arranged on the display screen of the display unit 203, and the like.

[0040] The storage unit 207 stores control programs and control data for the control unit 208, address data associated with names and telephone numbers of communication partners, sent and received e-mail data, Web data downloaded by Web browsing, downloaded content data, etc., and also temporarily stores streaming data, etc. The storage unit 207 is configured, for example, from a flash memory, a RAM (Random Access Memory), a ROM (Read Only Memory), etc.

[0041] The control unit 208 operates according to the control program and control data stored in the storage unit 207, and generally controls each unit of the smartphone 200. The control unit 208 also operates as the host device described above.

[0042] Such a smartphone 200 can use, for example, the detection result of the acceleration sensor 205 as, for example, a pedometer.

[0043] <Other> In addition to the above-described embodiment, various modifications can be made to the configuration of the invention without departing from the spirit of the invention. The above-described embodiment should be considered to be illustrative in all respects and not restrictive, and the technical scope of the present invention is indicated by the claims, not the description of the above-described embodiment, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0044] In the above-described embodiment, the sensor device was an acceleration sensor device that detects acceleration, but it may also be, for example, a gyro sensor that detects angular velocity, or a sensor device that detects physical quantities other than acceleration and angular velocity.

[0045] <Additional Notes> Regarding the present disclosure, specific configuration examples of which have been shown in the above-mentioned embodiments, additional notes will be provided.

[0046] The sensor device (102) of the present disclosure has a configuration (first configuration) including a first substrate (1) having a communication line (LN1), a second substrate (2) having a sensor element (6, C1), a signal processing unit (7) configured to process the output of the sensor element, an inversion unit (8) configured to generate an inverted signal of a communication signal transmitted by the communication line, and a capacitance (C2) provided between the output end of the inversion unit and the second substrate.

[0047] According to the sensor device of the first configuration, the capacitance injects into the second substrate a charge that is opposite in phase to the charge injected into the second substrate by the parasitic capacitance formed between the communication line and the second substrate. This makes it possible to cancel the effect on the output of the sensor device caused by the parasitic capacitance formed between the communication line and the second substrate injecting a charge into the second substrate by the capacitance injecting a charge of opposite phase into the second substrate. Therefore, according to the sensor device of the first configuration, it is possible to reduce the effect of communication noise on the output of the sensor device.

[0048] In the sensor device of the first configuration, the signal processing section and the inverting section may be mounted on the same chip (4) (second configuration).

[0049] In the sensor device of the second configuration, the capacitor may be mounted on the same chip (third configuration).

[0050] In the sensor device of the third configuration described above, a first end of the capacitance may be connected to the output end of the inversion section, and a second end of the capacitance may be connected to the second substrate via a connection line (W2) (fourth configuration).

[0051] In the sensor device of the first configuration described above, the first substrate may have a dummy wiring (DMY1), and the output end of the inversion unit may be connected to the dummy wiring via a connection line (W1_2) (fifth configuration).

[0052] In the sensor device of any of the first to fifth configurations, the communication signal may be a serial communication signal (sixth configuration).

[0053] In the sensor device of any one of the first to sixth configurations, the sensor element may be configured (seventh configuration) such that the characteristics of the sensor element change in response to acceleration.

[0054] A mobile device (200) of the present disclosure has a configuration (eighth configuration) including a sensor device having any one of the first to seventh configurations. [Explanation of symbols]

[0055] 1 First board 2 Second board 3 Lid 4. Semiconductor chips 5. Resin 6 Sensor element 7 CV converter 8. Inverter 101, 102 Sensor device 200 Smartphones 201 Communications Department 202 Camera Department 203 Display section 204 Audio input / output section 205 Acceleration Sensor 206 Operation section 207 Memory section 208 Control Unit C1 Sensing capacitance C2 capacity LN1 communication line LN2 Sensor drive line LN3 charge input line PC1~PC3 1st~3rd parasitic capacitance T1 communication terminal W1, W1_1, W1_2 First bonding wire W2 Second bonding wire

Claims

1. a first substrate having a communication line; a second substrate having a sensor element; a signal processor configured to process an output of the sensor element; an inverter configured to generate an inverted signal of a communication signal transmitted by the communication line; a capacitance provided between an output end of the inversion unit and the second substrate; A sensor device comprising:

2. The sensor device according to claim 1 , wherein the signal processing unit and the inversion unit are mounted on a single chip.

3. The sensor device according to claim 2 , wherein the capacitor is mounted on the same chip.

4. The sensor device according to claim 3 , wherein a first end of the capacitance is connected to an output end of the inverting unit, and a second end of the capacitance is connected to the second substrate via a connection line.

5. the first substrate has dummy wiring; The sensor device according to claim 1 , wherein an output terminal of the inverting unit is connected to the dummy wiring via a connection line.

6. The sensor device according to any one of claims 1 to 5, wherein the communication signal is a serial communication signal.

7. The sensor device according to any one of claims 1 to 5, wherein the sensor element is configured such that a characteristic thereof changes in response to acceleration.

8. A mobile device comprising the sensor device according to claim 1.

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