electronic machinery

Abstract

To provide an electronic apparatus capable of efficiently generating a beep sound regardless of a material of a back cover.SOLUTION: The electronic apparatus includes: a case (11) in which at least one end is open; a back cover (12) that has a flat plate portion (12a) in which at least a part thereof is non-metallic; and a circular frame portion (12b) that encloses the flat plate portion (12a), and is fixed to the case (11); a diaphragm (25) that is located inside the case (11) by facing the non-metallic portion of the flat plate portion (12a), and in which at least a part of the portion facing the flat plate portion (12a) is not fixed to the flat plate portion (12a); and a piezoelectric plate (24) that is provided on the diaphragm (25).SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] This invention relates to an electronic device.

Background Art

[0002] Conventionally, some electronic devices have a mechanism that performs a notification operation by generating a beep sound (ringing a buzzer). The beep sound is generated by periodically deforming a piezoelectric element by applying a varying voltage thereto and vibrating a diaphragm to which the piezoelectric element is attached at a frequency in the audible band.

[0003] In a portable electronic device, particularly a small and lightweight wearable device worn on the arm or the like, it is necessary to generate a beep sound in a limited space. In Patent Document 1, in order to suppress an increase in the thickness of an electronic wristwatch, a diaphragm and a piezoelectric element that were separated from both sides between the back cover and the internal mechanism are arranged in parallel with the internal mechanism. There is also a technique in which the metal back cover of an electronic wristwatch itself is used as a diaphragm.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the back cover is not made of metal, sufficient vibration does not occur in the back cover in response to the deformation of the piezoelectric element, and there is a problem that a beep sound with an appropriate volume cannot be obtained efficiently.

[0006] An object of this invention is to provide an electronic device that can efficiently generate a beep sound regardless of the material of the back cover.

Means for Solving the Problems

[0007] To achieve the above objective, the present invention A casing with at least one end open, A back cover having a cover portion which is at least partly non-metallic, and an annular frame portion which surrounds the cover portion and is fixed to the housing, A diaphragm is positioned inside the housing, facing the non-metallic portion of the cover, and at least a portion of the portion facing the cover is not fixed to the cover. A piezoelectric member provided on the diaphragm, Equipped with 、 The aforementioned back cover has a non-metallic cover portion fitted to a metal frame portion. The outer edge of the diaphragm is fixed between the frame and the cover at the fitted portion. It is an electronic device. [Effects of the Invention]

[0008] According to the present invention, it is possible to efficiently generate a beep sound regardless of the material of the back cover. [Brief explanation of the drawing]

[0009] [Figure 1] This is a bottom view of the electronic clock, which is an electronic device according to this embodiment. [Figure 2] This is a cross-sectional view of an electronic clock. [Figure 3] This is a modified version of the bottom view of an electronic clock. [Figure 4] This is a cross-sectional view showing a modified example of fixing the diaphragm. [Modes for carrying out the invention]

[0010] Hereinafter, embodiments of the present invention will be described based on the drawings. Figure 1 is a bottom view of the electronic clock 1, which is an electronic device of this embodiment. The electronic clock 1 comprises a case 11 (housing), a case back 12, and a bezel 14, among other components, as exposed on the exterior. The crown C is located on the side of the case 11. In this diagram, the lower part of the case back 12 is shown with some of the markings omitted.

[0011] Case 11 is a cylindrical component with open ends. Case 11 is a metal component, and the control unit, operating unit, and battery of the electronic device are located inside. The operating unit has a pointer, a gear train (gear train mechanism) or drive unit (movement) that rotates the pointer, etc. Alternatively, if the electronic clock uses a digital display system, the operating unit has a display screen such as a liquid crystal display screen instead of the above components. The control unit counts the date and time and performs control operations to cause the operating unit to display the date and time. These operating unit and control unit together are referred to as module 22.

[0012] The back cover 12 seals one end of the case 11. The end sealed by the back cover 12 is the back side of the electronic clock 1, that is, the side opposite to the front side where the hands and display screen are exposed. The flat plate portion 12a (covering portion) near the center of the back cover 12 is made of a material that allows the interior to be seen through. In this case, the diaphragm 25, which is a metal plate located inside the flat plate portion 12a, is visible through the flat plate portion 12a that covers it below. Near the center of the diaphragm 25, on the side opposite the back cover 12, is a piezoelectric plate 24 (piezoelectric component) which is hidden from view by the diaphragm 25.

[0013] The bezel 14 is positioned in a ring around the case 11 and is used to increase the robustness of the electronic watch 1 or for decorative purposes.

[0014] The crown C penetrates the case 11 and protrudes to the side of the electronic watch 1. The crown C can be pulled out, pushed back in, and rotated by the user, and operation signals corresponding to these operations are transmitted to the control unit inside the case 11.

[0015] Figure 2 is a cross-sectional view of the electronic clock 1 taken along the cross-sectional line AA in Figure 1. The bottom side of the case 11 is sealed by the back cover 12 via the packing 17 (O-ring) as described above, and the top side is sealed by the bezel 14 and the windshield member 15 via the packing 13 (O-ring). The windshield member 15 is fitted near the upper end of the inner surface of the annular bezel 14 by the packing 16.

[0016] The back cover 12 includes the above-mentioned flat plate portion 12a and a frame-shaped portion 12b (frame portion) that surrounds the flat plate portion 12a and is fixed to the case 11. The flat plate portion 12a is a light-transmissive member as described above and is fitted (mated) to the inner surface of the frame-shaped portion 12b via the packing 18. The fitting portion between the flat plate portion 12a and the frame-shaped portion 12b may be fixed together with an adhesive. The flat plate portion 12a is a non-metallic member having insulation properties, and is, for example, a sapphire plate whose interior can be visually recognized as described above. The frame-shaped portion 12b is a metal member here, and is, for example, stainless steel or titanium. The frame-shaped portion 12b has a groove in the circumferential direction and is screwed and fixed to the groove located on the inner surface of the case 11. Alternatively, the frame-shaped portion 12b may have a screw hole and be fixed to the case 11 with screws.

[0017] The windshield member 15 is a member that transmits light so that the interior can be visually recognized, and is, for example, a sapphire plate. The windshield member 15 is fitted to the inner surface of the bezel 14 via the packing 16. The packings 13, 16 to 18 are all resin members, and although not particularly limited, are, for example, rubber. Alternatively, the packings 13, 17 (O-rings) located in the gap with the case 11 and the other packings 16, 18 may be made of different materials. For example, the packings 16, 18 may be polytetrafluoroethylene (PTFE) or the like.

[0018] Inside the case 11, there are located a middle frame 21, the above-mentioned module 22 supported by the middle frame 21, a partition plate 23, a piezoelectric plate 24, a diaphragm 25, a first connection terminal 26, a second connection terminal 27, and the like.

[0019] The inner frame 21 is a support member shaped to fit into the corners of the frame-shaped portion 12b of the back cover 12, and stably fixes the module 22 inside the case 11. The trim plate 23 is an annular member located on the upper side of the module 22 along the inner edge of the bezel 14, and defines the display range by the operating part. Here, the trim plate 23 is separated into two parts, but is not limited to this. A buffer member 19 is sandwiched between the trim plate 23 and the bezel 14, thereby fixing the vertical position of the trim plate 23 between the module 22 and the crystal member 15.

[0020] The diaphragm 25 is made of a conductive metal and is a thin plate (at least thinner than the flat plate portion 12a of the back cover 12; for example, about 0.1 to 0.3 mm thick). It is positioned on the flat plate portion 12a of the back cover 12, facing (approximately parallel to, and overlapping in planar perspective) the flat plate portion 12a. The diaphragm 25 is in contact with the flat plate portion 12a but is not fixed by adhesive, meaning it can vibrate on the back cover 12. The outer edge of the diaphragm 25 is fixed to the back cover 12 in a state where it is sandwiched between the frame-shaped portion 12b and the flat plate portion 12a of the back cover 12. Therefore, when viewed from the bottom side (outside) of the back cover 12, the diaphragm 25 is visible through the entire flat plate portion 12a. The diaphragm 25 is made of a non-ferrous metal such as stainless steel (SUS, austenitic, etc.) or copper alloy (brass, etc.), and is more preferably made of a material that does not have ferromagnetism.

[0021] A second connection terminal 27 extends from module 22 to the diaphragm 25 and is in contact with it. The second connection terminal 27 has a bent portion in cross-section, and the area near this bent portion is in contact with the diaphragm 25. The area between the bent portion and module 22 is inclined with respect to the diaphragm 25, and if the distance between module 22 and the diaphragm 25 (back cover 12) changes temporarily due to vibration or shock of the electronic clock 1, this inclination angle changes, maintaining contact between the diaphragm 25 and the second connection terminal 27. This second connection terminal 27 is electrically connected to the housing grounding surface inside module 22, and therefore the diaphragm 25 is grounded to the housing.

[0022] The piezoelectric plate 24 is mounted on the diaphragm 25. The piezoelectric plate 24 is bonded to the center of the upper surface (opposite side of the back cover 12) of the diaphragm 25. The piezoelectric plate 24 is made of, for example, lead zirconate titanate and deforms in response to the application of voltage. For fixing the piezoelectric plate 24 to the diaphragm 25, for example, a conductive adhesive containing epoxy components is used, but it may be fixed with other materials as long as it is electrically conductive.

[0023] A first connection terminal 26 is in contact with the piezoelectric plate 24 on the side opposite to the surface that adheres to the diaphragm 25. The first connection terminal 26 is, for example, L-shaped in cross-section, and contacts the piezoelectric plate 24 with a line or surface, while the portion extending perpendicular to the piezoelectric plate 24 is expandable and contractible by a spring or the like. When the back cover 12 is attached to the case 11, this spring is held in a compressed state, so that even if the electronic clock 1 is subjected to vibration or shock, the contact state between the first connection terminal 26 and the piezoelectric plate 24 is maintained. The first connection terminal 26 extends from the module 22 and supplies a drive voltage to the piezoelectric plate 24. Because the drive voltage is a pulse waveform (including a trapezoidal wave, etc.) that has a periodic difference from the ground voltage, the piezoelectric plate 24 deforms periodically, and the diaphragm 25 vibrates in response. When the vibration period (frequency) is within the audible range, a beep sound is produced. In small electronic devices such as the electronic clock 1, the fixed outer edge of the diaphragm 25 does not constitute a complete fixed end for vibration; on the contrary, some of the vibration can be transmitted to the case 11 via the back cover 12 (frame-shaped portion 12b). From the standpoint of generating a beep sound, such transmission of vibration can actually improve the efficiency of beep sound generation.

[0024] Figure 3 is a modified example of the bottom view of the electronic clock 1 shown in Figure 1. In the above embodiment, the diaphragm 25 was a disc shape that completely covered the flat portion 12a of the back cover 12, but as shown in Figure 3, it may also have a shape with a portion missing.

[0025] Here, the area where the diaphragm 25 is missing corresponds to the area where the antenna 221 is located within the module 22 (inside the case 11) in a planar perspective view. The antenna 221 is, for example, a ferrite core antenna for receiving long waves. Because the diaphragm 25 is sufficiently thin, the shielding effect of radio waves on the antenna 221 is smaller compared to a conventional metal back cover. Furthermore, because the diaphragm 25 is shaped so that it does not overlap with at least a portion of the antenna 221 in a planar perspective view, higher sensitivity radio wave reception becomes possible.

[0026] Figure 4 is a cross-sectional view showing a modified example of fixing the diaphragm 25. The position of the cross-section is the same as that shown in Figure 2. The outer edge of the diaphragm 25 may be directly adhered to the flat plate portion 12a of the back cover 12. In this case, the back cover 12 is adhered with double-sided tape 28. In this case, the unadhered central portion (at least a part of it) of the diaphragm 25 may be separated from the flat plate portion 12a by a small gap (for example, about 0.2 to 0.3 mm) equal to the amount of the double-sided tape 28. In this modified example, the vibrable portion of the diaphragm 25 is narrower than the vibrable portion of the diaphragm 25 in the above embodiment by the amount that is adhered to the double-sided tape 28.

[0027] As described above, the electronic clock 1 of this embodiment comprises a case 11 with at least one end open, a back cover 12 having a flat plate portion 12a which is at least a part of which is nonmetallic, and an annular frame-shaped portion 12b which surrounds the flat plate portion 12a and is fixed to the case 11, a diaphragm 25 which is located inside the case 11 facing the nonmetallic portion of the flat plate portion 12a, and at least a part of the portion facing the nonmetallic portion is not fixed to the flat plate portion 12a (nonmetallic portion) of the back cover 12, and a piezoelectric plate 24 which is bonded and fixed on the diaphragm 25. Thus, since the diaphragm 25 can be vibrated independently of the flat plate portion 12a of the back cover 12, even if the flat plate portion 12a is made of a material that does not generate the vibration necessary to obtain the appropriate sound pressure, a beep sound can be efficiently produced without increasing the thickness of the electronic watch 1. In particular, since the flat plate portion 12a of the back cover 12 can be made of a non-metallic material, it can be in contact with the wrist with a different texture than metal, allowing users who are uncomfortable with metal to use the watch comfortably.

[0028] In particular, the portion of the diaphragm 25 that is not fixed to the flat plate portion 12a is in contact with the back cover 12 (especially the flat plate portion 12a). The diaphragm 25 is thin enough to vibrate appropriately in response to the deformation of the piezoelectric plate 24, so the thickness of the diaphragm 25 can be considered to the extent that it is almost unnecessary to consider, and the thickness of the electronic clock 1 is hardly increased.

[0029] Furthermore, the outer edge of the diaphragm 25 is fixed to the back cover 12. Because the outer edge of the diaphragm 25 is fixed to the back cover 12, the back cover 12 to which the diaphragm 25 is fixed can be easily attached to the case 11. Also, fixing the diaphragm 25 to the back cover 12 can be done before attaching the back cover 12 to the case 11, making the process easier. In particular, because the diaphragm 25 is in contact with and fixed to the frame-shaped portion 12b of the back cover 12, vibrations are transmitted to the case 11 via the frame-shaped portion 12b, allowing for more efficient beeping.

[0030] Furthermore, the back cover 12 has a non-metallic flat plate portion 12a fitted into a metal frame-shaped portion 12b, and the outer edge of the diaphragm 25 is sandwiched and fixed between the frame-shaped portion 12b and the flat plate portion 12a at the fitted portion of the back cover 12. This allows the diaphragm 25 to be fixed easily and securely without using adhesive members, thus reducing the number of necessary members. In addition, there is no need to secure space for adhesive.

[0031] Furthermore, the electronic clock 1 includes an antenna 221 located inside the case 11. The diaphragm 25 is positioned so as not to overlap with at least a portion of the antenna 221 in a planar perspective view. As a result, the radio waves received by the antenna 221 are not shielded by the diaphragm 25, thereby improving the reception sensitivity of the antenna 221.

[0032] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible. For example, the shape of the diaphragm 25 is not limited to those shown in the above embodiments and modifications. Other shapes are also possible.

[0033] Furthermore, although the above embodiment was described assuming that the frame-shaped portion 12b of the case back 12 is a metal member, the entire flat plate portion 12a and frame-shaped portion 12b may be made of a non-metallic material. In this case, the flat plate portion 12a and the frame-shaped portion 12b may be made of the same material or different materials. Also, the flat plate portion 12a and the frame-shaped portion 12b do not have to be separate members fitted together. The case back 12 may be a single, integrated piece from the beginning.

[0034] Furthermore, the flat plate portion 12a surrounded by the frame-shaped portion 12b does not have to be perfectly flat on both sides. The shape of the outer surface may be adjusted as appropriate to improve the wearing comfort, and the shape of the inner surface may have bends or irregularities to the extent that the thickness of the back cover 12 is not unnecessarily increased and the vibration of the diaphragm 25 is not significantly hindered. In addition, the shape of the diaphragm 25 may differ from a flat shape to the extent that it vibrates appropriately according to the shape of the inner surface of the back cover 12.

[0035] Furthermore, in the above embodiment, examples were given of the diaphragm 25 being fixed to the back cover 12 in which the outer edge is sandwiched between the flat plate portion 12a and the frame-shaped portion 12b, and in which it is bonded to the flat plate portion 12a, but the invention is not limited to these examples. When fixing the back cover 12 to the case 11, the outer edge of the diaphragm 25 may be sandwiched and fixed between the internal components of the case 11, such as the inner frame 21, and a part of the back cover 12.

[0036] Furthermore, if the diaphragm 25 is capable of vibrating relative to the back cover 12, it may have a portion that is partially fixed to the back cover 12 not only along its annular outer edge, but also in a more inward area.

[0037] Furthermore, although the above embodiment was described assuming that the electronic clock 1 has an antenna 221, the electronic device does not necessarily have to have an antenna inside the case 11. Also, the antenna does not have to be for receiving only; it may be an antenna capable of transmitting radio waves. For example, in addition to receiving long waves, the antenna 221 may also receive other radio waves, such as communication radio waves related to Bluetooth®.

[0038] Furthermore, although the above embodiment uses the electronic clock 1 as an example of an electronic device, other portable or wearable electronic devices that are required to be lightweight and compact may also be used, such as activity trackers or various sensors. Furthermore, the specific configurations, processing operations, and procedures shown in the above embodiments can be modified as appropriate without departing from the spirit of the present invention.

[0039] Although several embodiments of the present invention have been described, the scope of the present invention is not limited to the embodiments described above, but includes the scope of the invention as described in the claims and its equivalents. The invention described in the claims initially attached to the application for this patent is listed below. The claim numbers listed below are the same as those in the claims initially attached to the application for this patent.

[0040] [Note] <Claim 1> A casing with at least one end open, A back cover having a cover portion which is at least partly non-metallic, and an annular frame portion which surrounds the cover portion and is fixed to the housing, A diaphragm is positioned inside the housing, facing the non-metallic portion of the cover, and at least a portion of the portion facing the cover is not fixed to the cover. A piezoelectric member provided on the diaphragm, Electronic devices equipped with these features. <Claim 2> The electronic device according to claim 1, wherein the portion of the diaphragm that is not fixed to the cover portion is in contact with the back cover. <Claim 3> The electronic device according to claim 1 or 2, wherein the outer edge of the diaphragm is fixed to the back cover. <Claim 4> The aforementioned back cover has a non-metallic cover portion fitted to a metal frame portion. The outer edge of the diaphragm is fixed between the frame and the cover at the fitted portion. The electronic device according to claim 3. <Claim 5> The enclosure is equipped with an antenna located inside the enclosure, The diaphragm is located in a position that does not overlap with at least a portion of the antenna in a planar perspective view from one end. The electronic device according to any one of claims 1 to 4. [Explanation of Symbols]

[0041] 1. Electronic clock 11 cases 12 Case back 12a Flat plate part 12b Frame-shaped part 13, 16-18 packing 14 Bezel 15 Windshield component 19. Cushioning material 21 Middle frame 22 modules 221 Antenna 23 Trim board 24 Piezoelectric plate 25 Diaphragm 26 First connection terminal 27 Second connection terminal 28 Double-sided tape

Claims

1. A casing with at least one end open, A back cover having a cover portion which is at least partly non-metallic, and an annular frame portion which surrounds the cover portion and is fixed to the housing, A diaphragm is positioned inside the housing, facing the non-metallic portion of the cover, and at least a portion of the portion facing the cover is not fixed to the cover. A piezoelectric member provided on the diaphragm, Equipped with, The aforementioned back cover has a non-metallic cover portion fitted to a metal frame portion. The outer edge of the diaphragm is fixed between the frame and the cover at the fitted portion of the electronic device.

2. The electronic device according to claim 1, wherein the portion of the diaphragm that is not fixed to the cover portion is in contact with the back cover.

3. A housing having at least one end open, A back cover having a cover portion which is at least partly non-metallic, and an annular frame portion which surrounds the cover portion and is fixed to the housing, A diaphragm is positioned inside the housing, facing the non-metallic portion of the cover, and at least a portion of the portion facing the cover is not fixed to the cover. A piezoelectric member provided on the diaphragm, Equipped with, The outer edge of the diaphragm is bonded to the cover by an adhesive member, and there is a gap between the central portion of the diaphragm facing the cover and the cover, in which no other members are present.

4. The enclosure is equipped with an antenna located inside the enclosure, The diaphragm is located in a position that does not overlap with at least a portion of the antenna in a planar perspective view from one end. The electronic device according to any one of claims 1 to 3.

5. A retractable connecting terminal is in contact with the surface of the piezoelectric member opposite to the surface in contact with the diaphragm, and in a state in which the back cover is fixed to the housing, the connecting terminal is in a compressed state. The electronic device according to any one of claims 1 to 3.

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