Electronic device

Abstract

This electronic device comprises: a secondary battery having a first principal surface and a second principal surface aligned in the Z-axis direction; a rigid body facing the first principal surface; and a sensor that is attached to the rigid body and detects the elastic deformation of the rigid body caused by a force applied to the rigid body. The sensor does not overlap with the secondary battery when viewed in the Z-axis direction, and the first waveform of the signal output by the sensor when the first principal surface is in contact with the rigid body and the first pattern of force is applied to the rigid body is different from the second waveform of the signal output by the sensor when the first principal surface is not in contact with the rigid body and the first pattern of force is applied to the rigid body.

Description

[Technical field]

[0001] The present invention relates to an electronic device equipped with a secondary battery. [Background technology]

[0002] As a conventional invention relating to electronic devices, for example, there is known a method for measuring battery expansion described in Patent Document 1. In this method, a sensor for detecting battery expansion is attached to the battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] US Patent Application Publication No. 2021 / 0075068 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, there is a demand for a thinner electronic device capable of detecting battery expansion as described in Patent Document 1.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a thinner electronic device capable of detecting expansion of a secondary battery. [Means for solving the problem]

[0006] An electronic device according to one embodiment of the present invention includes: a secondary battery having a first principal surface and a second principal surface aligned in the Z-axis direction; A rigid body facing the first main surface; a sensor attached to the rigid body and configured to detect elastic deformation of the rigid body caused by application of a force to the rigid body; It is equipped with The sensor does not overlap the secondary battery when viewed in the Z-axis direction, A first waveform of a signal output by the sensor when a first pattern of force is applied to the rigid body while the first principal surface is in contact with the rigid body is different from a second waveform of a signal output by the sensor when the first pattern of force is applied to the rigid body while the first principal surface is not in contact with the rigid body. Effect of the Invention

[0007] According to the present invention, it is possible to reduce the thickness of an electronic device capable of detecting expansion of a secondary battery. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a top view of the electronic device 1. As shown in FIG. [Diagram 2] FIG. 2 is a cross-sectional view of the electronic device 1 taken along line AA. [Diagram 3] FIG. 3 is a top view of the sensor 6 and a cross-sectional view taken along line BB. [Figure 4] FIG. 4 is a waveform diagram of the signal output by the sensor 6. As shown in FIG. [Diagram 5] FIG. 5 is a cross-sectional view of the electronic device 1 taken along line AA. [Figure 6] FIG. 6 is a waveform diagram of the signal output by the sensor 6. As shown in FIG. [Figure 7] FIG. 7 is a front view of the display panel 4 and the sensor 6. As shown in FIG. [Figure 8] FIG. 8 is a front view of the display panel 4 and the sensor 6. As shown in FIG. [Figure 9] FIG. 9 is a front view of the display panel 4 and the sensor 6. As shown in FIG. [Figure 10] FIG. 10 is a front view of the display panel 4 and the sensor 6. As shown in FIG. [Figure 11] FIG. 11 is a block diagram of the electronic device 1. As shown in FIG. [Figure 12] FIG. 12 is a flowchart executed by the control device 20 of the electronic device 1. [Figure 13] FIG. 13 is a cross-sectional view of the electronic device 1a. [Figure 14] FIG. 14 is a cross-sectional view of the electronic device 1b. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Embodiment) An electronic device 1 according to an embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a top view of the electronic device 1. Figs. 2 and 5 are cross-sectional views of the electronic device 1 taken along line AA. Fig. 3 is a top view of the sensor 6 and a cross-sectional view taken along line BB. Figs. 4 and 6 are waveform diagrams of a signal output by the sensor 6. The vertical axis in Figs. 4 and 6 represents voltage. The horizontal axis in Figs. 4 and 6 represents time.

[0010] The electronic device 1 is, for example, a mobile communication terminal such as a smartphone. In this specification, the direction in which the main surfaces of the electronic device 1 are arranged is defined as the up-down direction. The main surfaces of the electronic device 1 have a rectangular shape. The direction in which the long sides of the main surfaces of the electronic device 1 extend is defined as the front-rear direction. The direction in which the short sides of the main surfaces of the electronic device 1 extend is defined as the left-right direction. The up-down direction, left-right direction, and front-rear direction are perpendicular to each other. As shown in Figures 1 and 2, the electronic device 1 includes a secondary battery 2, a housing 3, a display panel 4, and a sensor 6.

[0011] The housing 3 has a rectangular parallelepiped shape. However, the housing 3 does not have an upper surface as shown in Fig. 2. Therefore, the housing 3 is open upward.

[0012] The display panel 4 has a rectangular shape when viewed in the vertical direction, as shown in Fig. 1. The display panel 4 covers the opening of the housing 3, as shown in Fig. 2. This makes the housing 3 and the display panel 4 have a box shape. The display panel 4 is a rigid body. The display panel 4 is a liquid crystal display panel or an organic EL panel. The display panel 4 also has a built-in touch panel.

[0013] The secondary battery 2 is, for example, a lithium ion battery. The secondary battery 2 has a first main surface S1 and a second main surface S2 aligned in the vertical direction (Z-axis direction). The first main surface S1 is located above the second main surface S2. The secondary battery 2 is disposed in a space surrounded by the housing 3 and the display panel 4. The secondary battery 2 is located below the display panel 4. As a result, the display panel 4 (rigid body) faces the first main surface S1. The distance between the first main surface S1 and the display panel 4 (rigid body) is smaller than the thickness of the sensor 6 in the vertical direction when the secondary battery 2 is not expanded. For example, the distance between the first main surface S1 and the display panel 4 (rigid body) is 0.3 mm or more and 1.5 mm or less when the secondary battery 2 is not expanded.

[0014] The sensor 6 is attached to the display panel 4 (rigid body). In this embodiment, the sensor 6 is attached to the lower main surface of the display panel 4. The sensor 6 does not overlap with the secondary battery 2 when viewed in the up-down direction (Z-axis direction). The sensor 6 detects elastic deformation of the display panel 4 (rigid body) that occurs when a force is applied to the display panel 4 (rigid body). The sensor 6 will be described in detail below.

[0015] The sensor 6 has a rectangular shape when viewed in the vertical direction. The sensor 6 has long sides extending in the left-right direction. As shown in FIG. 3, the sensor 6 includes a piezoelectric film 14, an upper electrode 15a, and a lower electrode 15b. The piezoelectric film 14 has a sheet shape. Therefore, the piezoelectric film 14 has an upper main surface and a lower main surface. The length of the piezoelectric film 14 in the left-right direction is longer than the length of the piezoelectric film 14 in the front-back direction. In this embodiment, the piezoelectric film 14 has a rectangular shape with long sides extending in the left-right direction when viewed in the vertical direction. The piezoelectric film 14 generates an electric charge according to the deformation amount of the piezoelectric film 14. In this embodiment, the piezoelectric film 14 is a PLA film. The piezoelectric film 14 will be described in more detail below.

[0016] The piezoelectric film 14 has a characteristic that the polarity of the electric charge generated when the piezoelectric film 14 is stretched in the left-right direction is opposite to the polarity of the electric charge generated when the piezoelectric film 14 is stretched in the front-back direction. Specifically, the piezoelectric film 14 is a film formed from a chiral polymer. The chiral polymer is, for example, polylactic acid (PLA), particularly L-type polylactic acid (PLLA). PLLA made of a chiral polymer has a helical structure of the main chain. PLLA has a piezoelectricity in which the molecules are oriented by uniaxial stretching. The piezoelectric film 14 has a piezoelectric constant of d14. The uniaxial stretching direction (orientation direction) of the piezoelectric film 14 forms an angle of 45 degrees with respect to each of the front-back direction and the left-right direction. This 45 degrees includes, for example, an angle including about 45 degrees ±10 degrees. As a result, the piezoelectric film 14 generates an electric charge when the piezoelectric film 14 is stretched in the left-right direction or compressed in the left-right direction. For example, the piezoelectric film 14 generates a negative electric charge when stretched in the left-right direction. For example, when the piezoelectric film 14 is compressed in the left-right direction, it generates a positive charge. The magnitude of the charge depends on the amount of deformation of the piezoelectric film 14 due to expansion or compression. More precisely, the magnitude of the charge is proportional to the differential value of the amount of deformation of the piezoelectric film 14 due to expansion or compression.

[0017] The upper electrode 15a is a signal electrode. A detection signal is output from the upper electrode 15a. The upper electrode 15a is provided on the upper main surface of the piezoelectric film 14. The lower electrode 15b is a ground electrode. The lower electrode 15b is connected to ground. The lower electrode 15b is provided on the lower main surface of the piezoelectric film 14.

[0018] The electronic device 1 further includes a current / voltage conversion circuit and an amplifier circuit. However, since the current / voltage conversion circuit and the amplifier circuit are general circuits, a description thereof will be omitted.

[0019] In the sensor 6 described above, the upper electrode 15a is fixed to the lower main surface of the display panel 4 with double-sided tape or the like. This causes the sensor 6 to extend in the front-rear direction when the display panel 4 is pressed downward by a user. As a result, the sensor 6 outputs a signal having a positive voltage with respect to the reference potential V0, as shown in FIG.

[0020] Incidentally, when the secondary battery 2 is repeatedly charged and discharged, it expands as shown in FIG. 5. As a result, the first main surface S1 of the secondary battery 2 comes into contact with the display panel 4. In this case, the sensor 6 outputs a signal having a negative voltage with respect to the reference potential V0 as shown in FIG. 6. In this manner, the first waveform P1 (see FIG. 4) of the signal output by the sensor 6 when the force of the first pattern is applied to the display panel 4 (rigid body) in a state where the first main surface S1 is in contact with the display panel 4 (rigid body) is different from the second waveform P2 (see FIG. 6) of the signal output by the sensor 6 when the force of the first pattern is applied to the display panel 4 (rigid body) in a state where the first main surface S1 is not in contact with the display panel 4 (rigid body). In this embodiment, the polarity of the first waveform P1 with respect to the reference potential V0 is different from the polarity of the second waveform P2 with respect to the reference potential V0.

[0021] Here, the reason why the polarity of the first waveform P1 with respect to the reference potential V0 is different from the polarity of the second waveform P2 with respect to the reference potential V0 will be described with reference to the drawings. Figures 7 to 10 are front views of the display panel 4 and the sensor 6. In Figures 7 and 8, the first main surface S1 is not in contact with the display panel 4. In Figures 9 and 10, the first main surface S1 is in contact with the display panel 4.

[0022] As shown in Fig. 7, when the first main surface S1 is not in contact with the display panel 4 and no force is being applied to the display panel 4, the display panel 4 has a flat plate shape. When the user presses the display panel 4 downward, the display panel 4 curves so as to protrude downward, as shown in Fig. 8. At this time, the sensor 6 also curves together with the display panel 4. The sensor 6 is then stretched in the front-rear direction. As a result, the sensor 6 outputs a signal having a positive voltage with respect to the reference potential V0, as shown in Fig. 4.

[0023] On the other hand, as shown in Fig. 9, when the first main surface S1 is in contact with the display panel 4, the display panel 4 curves so as to protrude upward. When the user presses the display panel 4 downward in this state, as shown in Fig. 10, the display panel 4 deforms so that the portion pressed by the user protrudes downward and the portion where the sensor 6 is provided protrudes upward. At this time, the sensor 6 also curves together with the display panel 4. Then, the sensor 6 is compressed in the front-rear direction. As a result, as shown in Fig. 6, a signal having a negative voltage with respect to the reference potential V0 is output.

[0024] As described above, in the electronic device 1, the first waveform P1 of the signal output by the sensor 6 when the force of the first pattern is applied to the display panel 4 while the first main surface S1 is in contact with the display panel 4 is different from the second waveform P2 of the signal output by the sensor 6 when the force of the first pattern is applied to the display panel 4 while the first main surface S1 is not in contact with the display panel 4. Thus, the electronic device 1 can determine whether or not an abnormality has occurred in the secondary battery 2 based on the signal output by the sensor 6. The operation of the electronic device 1 will be described below with reference to the drawings. FIG. 11 is a block diagram of the electronic device 1. FIG. 12 is a flowchart executed by the control device 20 of the electronic device 1.

[0025] As shown in Fig. 11, the electronic device 1 further includes a control device 20. The control device 20 is, for example, a CPU (Central Processing Unit). The control device 20 executes a program stored in a storage device (not shown) to execute the flowchart shown in Fig. 12.

[0026] The control device 20 acquires a signal from the sensor 6 (step S1). Next, the control device 20 determines whether the polarity of the signal acquired in step S1 is negative (step S2). If the polarity of the signal is negative, the process proceeds to step S3. If the polarity of the signal is not negative, the process returns to step S1.

[0027] If the polarity of the signal is negative, the secondary battery 2 has expanded, causing the first main surface S1 to contact the display panel 4. The control device 20 then determines that an abnormality has occurred in the secondary battery 2 (step S3). The control device 20 stops charging the secondary battery 2 (step S4). Then, the control device 20 causes the display panel 4 to display that an abnormality has occurred (step S5). This ends the process.

[0028] [effect] According to the electronic device 1, it is possible to reduce the thickness of the electronic device 1, which is capable of detecting the expansion of the secondary battery 2. More specifically, in the method of measuring battery expansion described in Patent Document 1, a sensor for detecting battery expansion is attached to the battery. In this case, a space having a thickness equal to the sum of the thickness of the sensor and the thickness of the battery must be present in the housing.

[0029] On the other hand, the electronic device 1 includes a sensor 6 that detects elastic deformation of the display panel 4 caused by applying a force to the display panel 4. A first waveform P1 of a signal output by the sensor 6 when a force of a first pattern is applied to the display panel 4 in a state where the first main surface S1 is in contact with the display panel 4 is different from a second waveform P2 of a signal output by the sensor 6 when a force of the first pattern is applied to the display panel 4 in a state where the first main surface S1 is not in contact with the display panel 4. This allows the control device 20 to determine whether the first main surface S1 is in contact with the display panel 4 based on the waveform of the signal. That is, the control device 20 can detect the expansion of the secondary battery 2. This sensor 6 does not overlap with the secondary battery 2 when viewed in the vertical direction. Therefore, it is sufficient that a space having the thickness of the secondary battery 2 exists in the housing 3. As described above, according to the electronic device 1, it is possible to reduce the thickness of the electronic device 1 that can detect the expansion of the secondary battery 2. That is, the sensor 6 can be provided while maintaining the capacity of the secondary battery 2 of the electronic device 1.

[0030] Furthermore, the electronic device 1 can be made smaller. More specifically, the sensor 6 detects the elastic deformation of the display panel 4. Therefore, the control device 20 can calculate the magnitude of the force with which the user presses the display panel 4, using a signal from the sensor 6. Therefore, the sensor 6 functions as a pressing sensor and an expansion sensor for the secondary battery 2. As a result, the electronic device 1 does not require two sensors, and the electronic device 1 can be made smaller.

[0031] (Variation 1) An electronic device 1a according to a first modified example will be described below with reference to the drawings. Figure 13 is a cross-sectional view of the electronic device 1a.

[0032] The electronic device 1a differs from the electronic device 1 in that the electronic device 1a further includes a rigid body 5 and a deformation generating device 7. The rigid body 5 is, for example, a part of the housing of the electronic device 1a, a frame, a circuit board, or the like.

[0033] The deformation generating device 7 applies a force to the rigid body 5, thereby generating an elastic deformation in the rigid body 5. The deformation generating device 7 is a vibrator. The vibrator is, for example, an LRA, a voice coil motor, an eccentric motor, or the like. Therefore, the deformation generating device 7 vibrates. The rigid body 5 is elastically deformed by the vibration of the deformation generating device 7.

[0034] The sensor 6 is attached to the rigid body 5. The distance between the sensor 6 and the secondary battery 2 is shorter than the distance between the sensor 6 and the deformation generating device 7. The sensor 6 detects elastic deformation of the rigid body 5 caused by a force applied to the rigid body 5 by the deformation generating device 7. A first waveform P1 of a signal output by the sensor 6 when a force of a first pattern is applied to the rigid body 5 in a state where the first main surface S1 is in contact with the rigid body 5 is different from a second waveform P2 of a signal output by the sensor 6 when a force of the first pattern is applied to the rigid body 5 in a state where the first main surface S1 is not in contact with the rigid body 5. The other structures of the electronic device 1a are the same as those of the electronic device 1, and therefore description thereof will be omitted.

[0035] Since the distance between the sensor 6 and the secondary battery 2 is shorter than the distance between the sensor 6 and the deformation generating device 7, the rigid body 5 deforms as shown in FIG.

[0036] (Variation 2) An electronic device 1b according to a second modification will be described below with reference to the drawings. Figure 14 is a cross-sectional view of the electronic device 1b.

[0037] The electronic device 1b is a wireless earphone. The electronic device 1b includes a secondary battery 2, a housing 3, a sensor 6, a deformation generating device 7, and a control device 20. The deformation generating device 7 is a speaker. When generating sound, the deformation generating device 7 vibrates the housing 3. As a result, the deformation generating device 7 applies a force to the housing 3 (rigid body), thereby generating elastic deformation in the housing 3 (rigid body). The sensor 6 is attached to the housing 3 (rigid body), and detects the elastic deformation of the housing 3 (rigid body) that occurs when a force is applied to the housing 3 (rigid body). The other structures of the electronic device 1b are the same as those of the electronic device 1a, and therefore will not be described.

[0038] (Other embodiments) The electronic device according to the present invention is not limited to the electronic devices 1, 1a, and 1b, and can be modified within the scope of the invention.

[0039] The structures of the electronic devices 1, 1a, and 1b may be combined in any desired manner.

[0040] The polarity of the first waveform P1 with respect to the reference potential V0 does not have to be different from the polarity of the second waveform P2 with respect to the reference potential V0. Therefore, it is sufficient that the first waveform P1 is different from the second waveform P2. In other words, the polarity of the second waveform P2 with respect to the reference potential V0 may be the same as the polarity of the first waveform P1 with respect to the reference potential V0.

[0041] When the polarity of the signal is negative, the control device 20 notifies the user of an abnormality in the secondary battery 2. That is, when the polarity of the first waveform P1 with respect to the reference potential V0 differs from the polarity of the second waveform P2 with respect to the reference potential V0, the control device 20 notifies the user of an abnormality in the secondary battery 2. However, when the first waveform P1 and the second waveform P2 differ, the control device 20 may notify the user of an abnormality in the secondary battery 2 via the display panel 4 (notification device).

[0042] Note that the control device 20 stops charging the secondary battery 2 when the polarity of the signal is negative. That is, the control device 20 stops charging the secondary battery 2 when the polarity of the first waveform P1 with respect to the reference potential V0 and the polarity of the second waveform P2 with respect to the reference potential V0 are different. However, the control device 20 may stop charging the secondary battery 2 when the first waveform P1 and the second waveform P2 are different.

[0043] In addition, a flexible printed circuit board including the wiring of the sensor 6 may be integrated with the sensor 6.

[0044] The control device 20 may notify the user of an abnormality in the secondary battery 2 through a speaker. The sensor 6 may be a sensor that detects the user's grip of a game controller. In addition, when the electronic device 1, 1a is a smart watch, the sensor 6 may be a sensor that detects the user's pulse.

[0045] The material of the rigid body 5 is, for example, glass, metal, ceramic, or resin.

[0046] The present invention has the following structure.

[0047] (1) a secondary battery having a first principal surface and a second principal surface aligned in the Z-axis direction; A rigid body facing the first main surface; a sensor attached to the rigid body and configured to detect elastic deformation of the rigid body caused by application of a force to the rigid body; It is equipped with The sensor does not overlap the secondary battery when viewed in the Z-axis direction, a first waveform of a signal output by the sensor when a force of a first pattern is applied to the rigid body in a state where the first principal surface is in contact with the rigid body is different from a second waveform of a signal output by the sensor when a force of the first pattern is applied to the rigid body in a state where the first principal surface is not in contact with the rigid body; electronic equipment.

[0048] (2) The polarity of the first waveform with respect to a reference potential is different from the polarity of the second waveform with respect to the reference potential. (1) An electronic device as described in (1).

[0049] (3) The electronic device includes: a deformation generating device that applies a force to the rigid body to generate an elastic deformation in the rigid body, In addition, An electronic device as described in (1) or (2).

[0050] (4) The electronic device includes: A control device; A notification device; It is equipped with When the first waveform and the second waveform are different, the control device notifies a user of an abnormality in the secondary battery by the notification device. An electronic device according to any one of (1) to (3).

[0051] (5) The electronic device includes: The control device, It is equipped with The control device stops charging the secondary battery when the first waveform and the second waveform are different. An electronic device according to any one of (1) to (4).

[0052] (6) The distance between the first main surface and the rigid body is smaller than the thickness of the sensor in the Z-axis direction. An electronic device according to any one of (1) to (5).

[0053] (7) The distance between the first main surface and the rigid body is 1.5 mm or less. An electronic device according to any one of (1) to (6).

[0054] (8) The secondary battery expands to cause the first main surface to come into contact with the rigid body. An electronic device described in any one of (1) to (7). [Explanation of symbols]

[0055] 1,1a,1b:Electronic equipment 2: Secondary battery 3: Housing 4: Display panel 5: Rigid body 6: Sensor 7: Transformation Generator 20: Control device S1: First main surface S2: 2nd principal surface

Claims

1. a secondary battery having a first principal surface and a second principal surface aligned in the Z-axis direction; A rigid body facing the first main surface; a sensor attached to the rigid body and configured to detect elastic deformation of the rigid body caused by application of a force to the rigid body; It is equipped with The sensor does not overlap the secondary battery when viewed in the Z-axis direction, a first waveform of a signal output by the sensor when a force of a first pattern is applied to the rigid body in a state where the first main surface is in contact with the rigid body, is different from a second waveform of a signal output by the sensor when a force of the first pattern is applied to the rigid body in a state where the first main surface is not in contact with the rigid body; electronic equipment.

2. a polarity of the first waveform with respect to a reference potential is different from a polarity of the second waveform with respect to the reference potential; 2. The electronic device according to claim 1.

3. The electronic device includes: a deformation generating device that applies a force to the rigid body to generate an elastic deformation in the rigid body, In addition, 3. The electronic device according to claim 1 or 2.

4. The electronic device includes: A control device; A notification device; It is equipped with When the first waveform and the second waveform are different, the control device notifies a user of an abnormality in the secondary battery by the notification device.

3. The electronic device according to claim 1 or 2.

5. The electronic device includes: The control device, It is equipped with The control device stops charging the secondary battery when the first waveform and the second waveform are different.

3. The electronic device according to claim 1 or 2.

6. A distance between the first main surface and the rigid body is smaller than a thickness of the sensor in the Z-axis direction.

3. The electronic device according to claim 1 or 2.

7. The distance between the first main surface and the rigid body is 1.5 mm or less.

3. The electronic device according to claim 1 or 2.

8. The expansion of the secondary battery causes the first main surface to come into contact with the rigid body.

3. The electronic device according to claim 1 or 2.

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