Electronic device

Abstract

The invention provides an electronic device. The present invention is provided with: a flat-plate-shaped circuit board; an antenna provided on the circuit board and having an antenna pattern extending in a first direction parallel to the board surface of the circuit board; and a frame, at least a portion of which is electrically connected to the antenna via a ground plane of the circuit board, the frame including: a main frame, at least a portion of which overlaps the circuit board when viewed from a direction perpendicular to the board surface; and a conductive side frame connected to the main frame and extending in a direction substantially perpendicular to the board surface on a side of the circuit board, the electronic device being configured so that at least one of transmission and reception of radio waves of a desired wavelength is performed by a composite antenna having the antenna and the side frame.

Description

Technical Field

[0001] The present invention relates to an electronic device. Background Art

[0002] Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2008-241396, there has been a technique in which an antenna for communicating with the outside is disposed inside a portable electronic device. Summary of the Invention

[0003] An electronic device according to the present invention includes: a flat circuit board; an antenna disposed on the circuit board and having an antenna pattern extending in a first direction parallel to the surface of the circuit board; and a frame at least a part of which is electrically connected to the antenna via a ground plane of the circuit board and having: a main frame at least a part of which overlaps the circuit board when viewed from a direction perpendicular to the surface; and a conductive side frame connected to the main frame and extending in a direction substantially perpendicular to the surface on a side of the circuit board, and the electronic device is configured to transmit and / or receive radio waves of a desired wavelength by a composite antenna including the antenna and the side frame. Brief Description of the Drawings

[0004] Figure 1 It is a view showing an appearance of an electronic watch.

[0005] Figure 2 It is a perspective view of a module.

[0006] Figure 3 It is a view of the module showing a state where a cover member and a display unit are removed.

[0007] Figure 4 It is a view of a cross section of the module showing a position of a recess.

[0008] Figure 5 It is a top view of the circuit board and the frame member viewed from the -Z direction.

[0009] Figure 6 It is a view showing a positional relationship between the antenna pattern and the side frame.

[0010] Figure 7 It is a perspective view around an antenna portion in the circuit board and the frame member.

[0011] Figure 8 It is a view showing a result of numerical calculation of a gain distribution of the composite antenna of the present embodiment.

[0012] Figure 9 It is a view showing a result of numerical calculation of a gain distribution of the composite antenna of the present embodiment.

[0013] Figure 10 This is a graph showing the result of numerically calculating the gain distribution of the antenna in a wristwatch of a comparative example that does not have a composite antenna.

[0014] Figure 11 This is a graph showing the result of numerically calculating the gain distribution of the antenna in a wristwatch of a comparative example that does not have a composite antenna. DETAILED DESCRIPTION

[0015] In small electronic devices, due to design constraints, there are many cases where the area where an antenna can be disposed is limited. Therefore, it is difficult to provide an ideal antenna that can achieve a desired antenna sensitivity, and there is a problem that the antenna sensitivity tends to be low.

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Figure 1 This is a view showing the appearance of the wristwatch 1. The wristwatch 1 (electronic device) includes: a case 101 that houses a module 2 having a display unit 50 etc. inside (see Figure 2 ); and two watchbands 102 that are attached to the case 101. The wristwatch 1 is a watch that is worn on a user's wrist by winding the watchband 102 around the wrist. The display surface side of the display unit 50 in the case 101 is a transparent windproof glass, and the display of the display unit 50 can be visually confirmed through the windproof glass. The wristwatch 1 displays information such as time and date in the display unit 50.

[0017] Figure 2 This is a perspective view of the module 2. The module 2 includes a display unit 50, a flat circuit board 10 (see Figure 3 ), a housing 30 that houses the circuit board 10, and a frame member 20 that presses the housing 30 from the outside. A middle frame portion made of resin or the like that fills the gap between the module 2 and the case 101 may be provided. Hereinafter, directions will be represented by an XYZ orthogonal coordinate system with the center of the display surface of the display unit 50 as the origin. The normal direction of the display surface of the display unit 50 is set as the Z axis (+Z direction), and two axes parallel to the display surface are set as the X axis and the Y axis. Hereinafter, using the directions of each hour (1 o'clock to 12 o'clock) in the analog watch when facing the display unit 50, the azimuth in the XY plane is denoted as the "N o'clock direction". The 3 o'clock direction is set as the +X direction, and the 12 o'clock direction is set as the +Y direction. In addition, for any component, the +Z direction side of the component is denoted as the upper side, and the -Z direction side is denoted as the lower side.

[0018] The display unit 50 includes a liquid crystal display panel and a driving circuit for driving the liquid crystal display panel. The display unit 50 drives the liquid crystal display panel according to the control signal supplied from the circuit board 10, and thus performs digital display through the liquid crystal display panel. In addition, the display unit 50 may be an analog display unit that displays time or the like by rotating multiple hands on a dial.

[0019] The housing 30 includes a cover member 31 and a support member 32 that sandwich the circuit board 10 in the vertical direction. The materials of the cover member 31 and the support member 32 are, for example, resin. Figure 3 It is a diagram of the module 2 showing the state in which the cover member 31 and the display unit 50 are removed. In Figure 2 and Figure 3 In order to easily distinguish the cover member 31, the support member 32, and the frame member 20, the support member 32 is colored. Hereinafter, the upper surface of the circuit board 10 is referred to as the first surface 10a, and the lower surface is referred to as the second surface 10b. The cover member 31 supports the first surface 10a of the circuit board 10 from above, and the support member 32 supports the second surface 10b of the circuit board 10 from below.

[0020] As Figure 2 and Figure 3 shown, the outer shape of the module 2, that is, the outer shapes of the circuit board 10, the cover member 31, the support member 32, and the frame member 20, have fine irregularities when viewed from the direction perpendicular to the board surface (the first surface 10a or the second surface 10b) of the circuit board 10, that is, the Z direction, but are substantially circular. In addition, the cover member 31 and the support member 32 are substantially cylindrical. However, the outer shape of the module 2 is not limited to a circle and may be a rectangle or the like.

[0021] As Figure 2 shown, a substantially rectangular frame corresponding to the outer shape of the substantially rectangular display unit 50 is provided on the upper surface of the cover member 31. The display unit 50 is mounted on the upper surface of the cover member 31 in a state of being fitted into the frame. An opening (not shown) that penetrates the cover member 31 is provided in a portion of the cover member 31 that overlaps the display unit 50 when viewed from the Z direction. The display unit 50 is connected to the circuit board 10 through signal lines, power lines, etc. that pass through the opening.

[0022] In Figure 3 shown, various electronic components and electronic circuits for controlling the operation of the display unit 50 are provided mainly on the first surface 10a of the surface of the circuit board 10. In addition, a conductor forming a ground plane 11 that is set to a ground potential is formed on the surface of the circuit board 10. In Figure 3In [the figure], for ease of explanation, the ground plane 11 is depicted as a continuous plane, but the actual ground plane 11 is patterned according to the configuration and wiring of the electronic components and the electronic circuit. The ground plane 11 is provided on the first surface 10a and the second surface 10b respectively, and is electrically connected via vias penetrating the circuit board 10. Therefore, the ground plane 11 extends over both the first surface 10a and the second surface 10b.

[0023] An antenna unit 40 for wireless communication with an external device is provided at a peripheral portion in the direction of approximately 11 o'clock on the first surface 10a of the circuit board 10. For example, when the distance from the center (origin) of the circuit board 10 to the end (the radius in this embodiment) as viewed from the Z direction is set to d, the peripheral portion of the circuit board 10 is a region where the distance from the center is greater than 0.8d. In this embodiment, the wireless communication is Bluetooth (registered trademark). The antenna unit 40 is designed to be capable of transmitting and receiving radio waves in the frequency band used in Bluetooth, i.e., 2.4 GHz to 2.48 GHz. Hereinafter, the wavelength of the radio waves in the above frequency band is denoted as λ. λ is approximately 120 to 124 mm, and λ / 4 is approximately 30 to 31 mm.

[0024] The antenna unit 40 has an antenna pattern 41 extending in a first direction D1 (a predetermined direction) parallel to the first surface 10a of the circuit board 10 and an antenna chip 42 connected to the antenna pattern 41. The first direction D1 is a direction perpendicular to the 11 o'clock direction, that is, when expressed in terms of the azimuth angle with the X-axis set to 0°, it is the direction of +30°. However, the first direction D1 is not limited to this and can be appropriately adjusted according to the installation positions of other components, etc.

[0025] The antenna pattern 41 is a linear (rod-shaped) metal conductor provided on the first surface 10a. The antenna pattern 41 constitutes a grounded monopole antenna using the above-mentioned ground plane 11. The antenna chip 42 is, for example, an electronic component for obtaining a wavelength shortening effect in the operating frequency band. By providing the antenna chip 42 that provides a wavelength shortening effect on the basis of making the length of the antenna pattern 41 shorter than λ / 4 (for example, on the basis of setting it to a length of about λ / 8), radio waves in the Bluetooth frequency band can be transmitted and received. When the wavelength shortening based on the antenna chip 42 is not required, etc., the antenna chip 42 can also be omitted.

[0026] The antenna chip 42 is electrically connected to the ground plane 11 via an RF matching circuit (not shown) etc. Hereinafter, the connection position of the antenna unit 40 and the ground plane 11 is denoted as the ground point P1. In addition, the ground point P1 is near the power supply point for inputting a transmission signal to the antenna unit 40 or extracting a reception signal from the antenna unit 40, and the ground point P1 is regarded as being in substantially the same position as the power supply point.

[0027] As Figure 3As shown, the support member 32 supports substantially the entire second surface 10b of the circuit board 10. A part of the peripheral portion of the upper surface of the support member 32 becomes an exposed portion not covered by the circuit board 10. Three recesses 322 are provided in this exposed portion.

[0028] Figure 4 FIG. is a cross-sectional view of the module 2 at the position of the recess 322. As Figure 4 shown, the cover member 31 has a convex portion 312 extending in the -Z direction toward the support member 32 on its lower surface. The cover member 31 has three convex portions 312, and the support member 32 has three recesses 322 that fit with the respective convex portions 312 at positions corresponding to the three convex portions 312. By fitting the convex portions 312 and the recesses 322 at three locations, the cover member 31 and the support member 32 are joined in a predetermined positional relationship and do not shift relative to each other in the XY plane direction. In addition, a convex portion extending in the +Z direction toward the cover member 31 may be provided on the upper surface of the support member 32, and a recess may be provided at a position corresponding to the convex portion in the cover member 31.

[0029] Return Figure 2 , the cover member 31 covers at least a part of the first surface 10a of the circuit board 10. Six protruding engaging portions 311 are provided on the side surface (the cylindrical surface connecting the upper surface and the lower surface) of the cover member 31. The engaging portions 311 are provided at positions in the 1 o'clock direction, 3 o'clock direction, 5 o'clock direction, 7 o'clock direction, 9 o'clock direction, and 11 o'clock direction on the side surface. That is, the six engaging portions 311 are provided at substantially equal intervals along the outer periphery of the circuit board 10. "Substantially equal intervals" includes, in addition to the case of equal intervals, for example, the case where the minimum value of the intervals is 0.9 times or more of the maximum value.

[0030] As Figure 2 and Figure 3 shown, the frame member 20 includes a main frame 21 located below the support member 32 and abutting against the lower surface of the support member 32, and a plurality of side frames 22 connected to the main frame 21. Each side frame 22 extends in a direction (+Z direction) perpendicular to the first surface 10a on the side of the circuit board 10. In addition, each side frame 22 does not have to be perpendicular to the first surface 10a and may extend obliquely in a direction substantially perpendicular to the first surface 10a. The main frame 21 and each side frame 22 are made of a conductive metal.

[0031] Figure 5 FIG. is a plan view of the circuit board 10 and the frame member 20 as viewed from the -Z direction. Figure 5 FIG. is a view omitting the support member 32 and showing the positional relationship between the circuit board 10 and the frame member 20. As Figure 5As shown, the main frame 21 of the frame member 20 overlaps at least a part of the circuit board 10 when viewed from the -Z direction. Specifically, the main frame 21 is an annular member having a part that overlaps the peripheral portion of the circuit board 10 when viewed from the -Z direction, and the central portion forms an opening. However, the shape of the main frame 21 is not limited to Figure 5 the shape shown. As long as it is a shape that overlaps at least a part of the circuit board 10 when viewed from the -Z direction. The frame member 20 has a bamboo-shaped connection frame 23 protruding from the inner circumference of the main frame 21. The connection frame 23 extends obliquely from the main frame 21 toward the circuit board 10, that is, in a direction having a +Z direction component, and the front end contacts the ground plane 11 of the second surface 10b of the circuit board 10. Hereinafter, the position where the connection frame 23 contacts the ground plane 11 of the circuit board 10, that is, the position of electrical connection, is denoted as the connection point P2. The frame member 20 is electrically connected to the antenna unit 40 via the connection point P2 and the ground point P1 in the ground plane 11 of the circuit board 10.

[0032] As Figure 2 and Figure 3 shown, the frame member 20 has side frames 22 at positions (engagement positions) corresponding to the six engagement portions 311 of the cover member 31. In each side frame 22, an opening 221 is provided at a position corresponding to the engagement portion 311. By engaging (hooking) the engagement portion 311 with the opening 221, the positional relationship between each side frame 22 and the cover member 31 is fixed. The frame member 20 is fixed to the cover member 31 and the support member 32 in a state where the cover member 31 and the support member 32 sandwich the circuit board 10 by the main frame 21 abutting against the support member 32 and the engagement portions 311 of the respective side frames 22 engaging with the cover member 31. The side frames 22 located in the 1 o'clock direction, 5 o'clock direction, 7 o'clock direction, and 11 o'clock directions are substantially rectangular. "Substantially rectangular" includes, for example, a shape obtained by chamfering the corners of a rectangle. The side frames 22 located in the 3 o'clock direction and 9 o'clock directions have a portion where the opening 221 is provided and portions extending left and right from this portion to support the side surface of the support member 32. The number of the engagement portions 311 and the number of the corresponding side frames 22 are not limited to six, and at least three may be provided in such a manner that the cover member 31 and the support member 32 can be stably fixed. Instead of the opening 221, a notch portion corresponding to a shape in which a notch is cut from the side surface of the side frame 22 may be provided. In this case, the engagement portion 311 is formed in a protruding shape that engages with the notch portion.

[0033] The side frame 22 (the side frame 22 located in the 11 o'clock direction) of the six side frames 22 near the antenna pattern 41 functions as an antenna together with the antenna pattern 41. Hereinafter, the positional relationship between this one side frame 22 and the antenna pattern 41, and the electrical action of this side frame 22, etc. will be described.

[0034] Figure 6 It is a perspective view of the periphery of the antenna unit 40 in the circuit board 10 and the frame member 20. Figure 6 It is a perspective view of the circuit board 10 and the frame member 20 as viewed from the lower side. The side frame 22 is electrically connected to the connection point P2 on the ground plane 11 of the circuit board 10 via the main frame 21 and the connection frame 23. Therefore, the side frame 22 is electrically connected to the antenna pattern 41 of the antenna unit 40 via the ground plane 11. With such a structure, the side frame 22 and the antenna pattern 41 similarly constitute a ground-type monopole antenna using the ground plane 11. Alternatively, the side frame 22 and the antenna pattern 41 may constitute a dipole antenna. Therefore, the side frame 22 and the antenna pattern 41 function as two monopole antennas and / or dipole antennas.

[0035] Figure 7 It is a diagram showing the positional relationship between the antenna pattern 41 and the side frame 22. As Figure 7 shown, the side frame 22 is provided at a position facing and orthogonal (crossing) to the antenna pattern 41 when viewed from the second direction D2 that is perpendicular to the first direction D1 and parallel to the first surface 10a of the circuit board 10. When viewed from the second direction D2, the angle formed by the antenna pattern 41 and the side frame 22 is the angle formed by the first direction D1 in which the antenna pattern 41 extends and the extending direction of the side frame 22. In this specification, the extending direction of the side frame 22 is set as the side that forms the outer shape of the side frame 22 and extends from the connection portion with the main frame 21 toward the front end direction of the side frame 22 (the two sides extending in the vertical direction in Figure 7 ). Therefore, when the antenna pattern 41 and the side frame 22 are orthogonal when viewed from the second direction D2, it means that the first direction D1 in which the antenna pattern 41 extends is orthogonal to the side extending in the Figure 7 vertical direction in the side frame 22. In addition, no other conductive members are provided between the side frame 22 and the antenna pattern 41. Most preferably, the side frame 22 crosses at the center of the antenna pattern 41 when viewed from the second direction. However, even if the side frame 22 is shifted left and right from the center position of the antenna pattern 41, it sufficiently functions as an antenna. When the antenna pattern 41 and the side frame 22 are parallel when viewed from the second direction D2, when the current amplitudes generated in the antenna pattern 41 and the side frame 22 are in opposite phases, they cancel each other out and the radiation weakens. In contrast, by arranging the antenna pattern 41 and the side frame 22 to be orthogonal when viewed from the second direction D2 as in the present embodiment, it is difficult to generate a phenomenon in which the current amplitudes cancel each other out, and the antenna sensitivity can be effectively improved. In addition, by setting the above configuration, it is possible to ensure the gain (sensitivity) for both horizontal polarization waves and vertical polarization waves.

[0036] Return Figure 6, the conduction path from the grounding point P1 of the antenna unit 40, through the circuit board 10, to the connection point P2 which is the connection position of the connection frame 23, and then to the front end P3 of the side frame 22 has a length approximately equivalent to λ / 4. Specifically, the sum of the first conduction path R1 from the grounding point P1 to the connection point P2 in the ground plane 11 of the circuit board 10 and the second conduction path R2 from the connection point P2, through the connection frame 23 and the main frame 21, to the front end P3 of the side frame 22 becomes a length approximately equivalent to λ / 4. By satisfying such a configuration condition, the side frame 22 functions as an antenna capable of transmitting and receiving Bluetooth radio waves. Herein, "a length approximately equivalent to λ / 4" includes aλ / 4 when the wavelength λ is shortened to the wavelength aλ (a < 1; wavelength shortening rate) according to the dielectric constant of the components located around the conduction path. For example, when the wavelength shortening rate a is in the range of 0.67 or more and 1 or less, "a length approximately equivalent to λ / 4" includes the range from 0.67λ / 4 or more to λ / 4 or less. Additionally, "a length approximately equivalent to λ / 4" includes a certain range centered on aλ / 4 considering the wavelength shortening. The certain range can be, for example, the range from 0.8×aλ / 4 or more to 1.2×aλ / 4 or less. Therefore, when the wavelength shortening rate a is in the range of 0.67 or more and 1 or less, "a length approximately equivalent to λ / 4" includes the range from 0.8×0.67λ / 4 or more to 1.2×λ / 4 or less.

[0037] Hereinafter, the structure having the antenna unit 40 and the side frame 22 functioning as an antenna, and being used for at least one of transmission and reception of radio waves of a desired wavelength is denoted as "composite antenna A (refer to Figure 6 )". The composite antenna A has the antenna unit 40, the first part in the ground plane 11 from the grounding point P1 to the connection point P2 (the part corresponding to the first conduction path R1), and the second part in the frame member 22 from the connection point P2 to the front end P3 of the side frame 22 (the part corresponding to the second conduction path R2). The second part among them includes the connection frame 23, a part of the main frame 21, and the side frame 22. The side frame 22 intersects the antenna pattern 41 when observed from the second direction D2 and satisfies the above configuration condition, whereby the side frame 22 can appropriately function as an antenna and improve the antenna sensitivity of the antenna unit 40. In other words, a composite antenna A with an antenna sensitivity higher than that of the antenna unit 40 alone can be formed.

[0038] Next, the improvement effect of the antenna sensitivity (antenna gain) of the composite antenna A of the present embodiment will be described. Figure 8 And Figure 9 are diagrams showing the results of numerical calculation of the gain distribution of the composite antenna A of the present embodiment. Among them, Figure 8 shows the gain distribution in the X-Z plane, Figure 9Represents the gain distribution in the Y-Z plane. Additionally, Figure 8 and Figure 9 represent the distribution of the combined gain of the gain of the vertically polarized wave and the gain of the horizontally polarized wave. As Figure 8 and Figure 9 shown, the electronic watch 1 according to the present embodiment obtains a gain of -3.4 dBi in the +Z direction.

[0039] Figure 10 and Figure 11 are diagrams showing the results of numerical calculations of the gain distribution of the antenna in an electronic watch of a comparative example that does not have the composite antenna A. The electronic watch of the comparative example is equivalent to removing the side frames 22 at the 11-point directions shown in Figure 2 and Figure 3 (the side frames 22 near the antenna pattern 41) from the electronic watch 1 of the present embodiment. Similar to Figure 8 and Figure 9 , Figure 10 represents the distribution of the combined gain of the vertically polarized wave and the horizontally polarized wave in the X-Z plane, Figure 11 represents the distribution of the combined gain in the Y-Z plane. As Figure 10 and Figure 11 shown, in the electronic watch of the comparative example, the gain in the +Z direction becomes -6.7 dBi. Therefore, based on Figure 8 and Figure 9 compared with Figure 10 and Figure 11 , it is confirmed that by adopting the structure of the present embodiment with the composite antenna A, a gain improvement (sensitivity improvement) of 3.3 dBi is achieved.

[0040] (Effect)

[0041] As described above, the electronic watch 1 of the present embodiment includes: a flat circuit board 10; an antenna unit 40 provided on the circuit board 10 and having an antenna pattern 41 extending in a first direction D1 parallel to the board surface of the circuit board 10; and a frame member 20. At least a part of the frame member 20 is electrically connected to the antenna unit 40 via the ground plane 11 of the circuit board 10. The frame member 20 includes: a main frame 21 that at least partially overlaps the circuit board 10 when viewed from the Z direction; and a conductive side frame 22 that is connected to the main frame 21 and extends in the +Z direction on the side of the circuit board 10. The electronic watch 1 is configured to perform at least one of transmission and reception of radio waves of a desired wavelength through the composite antenna A including the antenna unit 40 and the side frame 22. With such a structure, the side frame 22 of the frame member 20 can function as an antenna. Therefore, the impact resistance and reliability of the module 2 can be ensured by the frame member 20, and the antenna sensitivity of the antenna unit 40 can be improved by the side frame 22 functioning as an antenna. That is, a composite antenna A with higher antenna sensitivity than the antenna unit 40 alone can be formed. In addition, since the side frame 22 functions as an antenna, there is no need to add a new structure to improve the antenna sensitivity. Therefore, the antenna sensitivity can be improved without increasing the size and manufacturing cost of the electronic watch 1.

[0042] In addition, the side frame 22 is provided at a position where it intersects the antenna pattern 41 when viewed from a second direction D2 perpendicular to the first direction D1 and parallel to the above-mentioned board surface. Thus, by setting the configuration such that the antenna pattern 41 intersects (orthogonal in the present embodiment) the side frame 22, it is possible to make it difficult for the current amplitude generated in the antenna pattern 41 and the current amplitude generated in the side frame 22 to cancel each other out. In addition, by setting the above configuration, it is possible to ensure the gain (sensitivity) for both horizontally polarized waves and vertically polarized waves. Thereby, the antenna sensitivity of the antenna unit 40 can be effectively improved by the side frame 22. In addition, the side frame 22 provided in the direction intersecting the antenna pattern 41 and the board surface of the circuit board 10 effectively functions to stably fix the cover member 31 and the support member 32. Therefore, through the side frame 22, the structural stability, impact resistance, and reliability of the product can be ensured, and the antenna sensitivity can be improved. In addition, the antenna pattern 41 and the side frame 22 may also intersect when viewed from the second direction, which is related to the reduction of design constraints. Therefore, it is possible to improve the antenna sensitivity while ensuring the design freedom.

[0043] Moreover, the electronic watch 1 includes: a cover member 31 that covers at least a part of the first surface 10a of the circuit board 10 on the side opposite to the main frame 21 side and has an engaging portion 311 that engages with the side frame 22. Thereby, the circuit board 10 can be protected by the cover member 31, and the circuit board 10 can be fixed by the frame member 20 via the cover member 31.

[0044] In addition, the frame member 20 has a plurality of side frames 22 located on the sides of the circuit board 10, and one of the plurality of side frames 22 is disposed at a position facing and intersecting the antenna pattern 41 when viewed from the second direction D2. Thereby, one of the plurality of side frames 22 can function as an antenna.

[0045] In addition, the antenna pattern 41 is located at the peripheral portion of the circuit board 10, and no conductive member is provided between the above-mentioned one of the plurality of side frames 22 and the antenna pattern 41. Thereby, the antenna pattern 41 can be brought close to the side frame 22, and the effect of improving the antenna sensitivity based on the side frame 22 can be effectively improved.

[0046] In addition, the above-mentioned one of the plurality of side frames 22 has a substantially rectangular shape. Thereby, the linear portion included in the substantially rectangular side frame 22 can effectively function as an antenna.

[0047] In addition, the cover member 31 has a plurality of engaging portions 311 provided at substantially equal intervals along the outer periphery of the circuit board 10, and the frame member 20 has a plurality of side frames 22 at positions corresponding to the plurality of engaging portions 311. Thereby, the cover member 31 and the support member 32 can be stably fixed by using the frame member 20 having the plurality of side frames 22.

[0048] In addition, openings 221 are respectively provided in the plurality of side frames 22, and the cover member 31 has a plurality of protruding engaging portions 311 that engage with the openings 221. Thereby, each side frame 22 can be reliably engaged with each engaging portion 311, and the cover member 31 and the support member 32 can be reliably fixed.

[0049] In addition, the frame member 20 has a connection frame 23 that extends from the main frame 21 toward the circuit board 10 and is electrically connected to the ground plane 11 provided on the circuit board 10. Thereby, the side frame 22 can be electrically connected to the ground plane 11 via the main frame 21 and the connection frame 23.

[0050] In addition, the conduction path from the connection point P2, which is the connection position between the antenna portion 40 and the connection frame 23 via the circuit board 10, to the front end P3 of the side frame 22 has a length substantially equivalent to 1 / 4 of the wavelength of the radio wave transmitted or received by the antenna portion 40. Thereby, the side frame 22 functions appropriately as an antenna, and thus the sensitivity of the antenna portion 40 can be effectively improved.

[0051] In addition, there is a support member 32 that supports substantially the entire second surface 10b of the circuit board 10 opposite to the first surface 10a. The frame member 20 abuts against the support member 32 through the main frame 21, and the side frame 22 engages with the engaging portion 311 of the cover member 31, so that the cover member 31 and the support member 32 are fixed in a state where the circuit board 10 is clamped between the cover member 31 and the support member 32. Thereby, the circuit board 10 can be protected by the housing 30 formed by the cover member 31 and the support member 32, and the housing 30 can be fixed by the frame member 20.

[0052] In addition, the cover member 31 has a convex portion 312 extending in the -Z direction toward the support member 32, and the support member 32 has a concave portion 322 that engages with the convex portion 312 at a position corresponding to the convex portion 312. Thereby, the cover member 31 and the support member 32 can be prevented from shifting in the XY plane direction.

[0053] (Other)

[0054] In addition, the present invention is not limited to the above-described embodiments, and various changes can be made.

[0055] For example, in the above-described embodiment, the side frame 22 is illustrated as being orthogonal to the antenna pattern 41 when viewed from the second direction D2, but it is not limited thereto. The side frame 22 and the antenna pattern 41 may also intersect obliquely when viewed from the second direction D2.

[0056] In addition, if the side frame 22 satisfies the above-described configuration condition (the condition that the sum of the first conduction path R1 and the second conduction path R2 is a length approximately equivalent to λ / 4), the side frame 22 may also be configured such that it does not intersect the antenna pattern 41 when viewed from the second direction D2. With the side frame 22 configured in this way, the effect of enhancing the antenna sensitivity of the antenna unit 40 can also be obtained.

[0057] In addition, the wireless communication method is not limited to Bluetooth. In the case of using other communication methods, the length of the conduction path (the sum of the first conduction path R1 and the second conduction path R2) from the antenna unit 40 to the front end of the side frame 22 can be adjusted according to the frequency of the radio wave used in this communication method.

[0058] In addition, the case where the entire frame member 20 is made of a conductive metal is illustrated, but it is not limited thereto. It is sufficient that at least the side frame 22 that functions as an antenna in the frame member 20 and the conduction path from the front end P3 of the side frame 22 to the connection point P2 of the connection frame 23 have conductivity, and other parts may be insulating members such as resin.

[0059] In addition, in the above-described embodiment, an example in which the protruding engaging portion 311 provided on the side surface of the lid member 31 is engaged with the opening 221 of the side frame 22 of the frame member 20 has been described. However, the method of engaging the lid member 31 with the side frame 22 is not limited thereto. For example, a concave engaging portion may be provided on the side surface of the lid member 31, and a protruding portion having a shape that engages with the engaging portion may be provided on the surface of the side frame 22 that faces the side surface of the lid member 31, and the protruding portion engages with the concave engaging portion of the lid member 31.

[0060] In addition, in the above-described embodiment, the case where the antenna pattern 41 is completely linear has been described, but it may be slightly bent. For example, the corners of the antenna pattern 41 may be bent into an L shape and extend locally in different directions. In addition, the entire antenna pattern 41 may be slightly bent (for example, by 30 degrees or less) and evenly oriented in a certain direction. In this case, that direction can be regarded as the first direction D1.

[0061] In addition, in the above-described embodiment, an example in which the antenna pattern 41 and the side frame 22 are provided in the 11 o'clock direction has been described. However, it is not limited thereto, and they may be provided in a direction other than 11 o'clock.

[0062] In addition, although the electronic watch 1 has been exemplified as the electronic device, it is not limited thereto. The electronic device may also be any wearable device such as a motion sensor terminal or a pedometer that measures a motion state and is worn on a user's body. In addition, the electronic device may also be a portable device such as a smartphone or a tablet terminal.

[0063] In addition, regarding the detailed structure and detailed operation of each component of the electronic watch 1 in the above-described embodiment, it is of course possible to appropriately change them without departing from the gist of the present invention.

[0064] The embodiments of the present invention have been described, but the scope of the present invention is not limited to the above-described embodiments, and includes the scope of the invention described in the scope of the technical solution and its equivalent scope.

Claims

1. An electronic device, characterized in that: have: A flat circuit substrate; an antenna, which is disposed on the circuit substrate and has an antenna pattern extending along a first direction parallel to a board surface of the circuit substrate; as well as A frame, at least a portion of which is electrically connected to the antenna via a ground plane of the circuit substrate, comprising: a main frame, at least a portion of which overlaps with the circuit substrate when viewed from a direction perpendicular to the board surface; and a conductive side frame connected to the main frame and extending on the side of the circuit substrate in a direction substantially perpendicular to the board surface, The electronic device is configured to perform at least one of transmission and reception of radio waves having a desired wavelength using a composite antenna including the antenna and the side frame.

2. The electronic device according to claim 1, characterized in that: The side frame is provided at a position intersecting the antenna pattern when viewed from a second direction that is perpendicular to the first direction and parallel to the board surface.

3. The electronic device according to claim 1 or 2, characterized in that: A cover is provided, the cover covers at least a portion of a first surface of the circuit board which is a surface on the side opposite to the main frame side, and has an engaging portion engaged with the side frame.

4. The electronic device according to claim 3, characterized in that: The frame has a plurality of side frames located on the sides of the circuit substrate. One of the plurality of side frames is provided at a position facing and intersecting the antenna pattern when viewed from a second direction that is perpendicular to the first direction and parallel to the board surface.

5. The electronic device according to claim 4, characterized in that: The antenna pattern is located at the periphery of the circuit substrate. No conductive member is provided between one side frame among the plurality of side frames and the antenna pattern.

6. The electronic device according to claim 4 or 5, characterized in that: One of the plurality of side frames has a substantially rectangular shape.

7. The electronic device according to any one of claims 4 to 6, characterized in that: The cover has a plurality of the engaging portions arranged at substantially equal intervals along the outer circumference of the circuit substrate. The frame has a plurality of the side frames at positions corresponding to the plurality of engagement portions.

8. The electronic device according to claim 7, characterized in that: A plurality of side frames are respectively provided with notches or openings. The cover has a plurality of protrusion-shaped engaging portions that engage with the notch portion or the opening portion.

9. The electronic device according to any one of claims 1 to 8, characterized in that: The frame includes a connection frame extending from the main frame toward the circuit substrate and electrically connected to the ground plane provided on the circuit substrate.

10. The electronic device according to claim 9, characterized in that: The conduction path from the antenna to the front end of the side frame via the connection position of the circuit board and the connection frame has a length substantially equivalent to 1 / 4 of the wavelength of the radio wave transmitted or received by the antenna.

11. The electronic device according to any one of claims 3 to 8, characterized in that: A supporting member is provided, the supporting member supporting substantially the entire second surface of the circuit substrate on the side opposite to the first surface, The frame fixes the cover and the support member in a state where the cover and the support member sandwich the circuit substrate, by causing the main frame to abut against the support member and the side frame to engage with the engagement portion of the cover.

12. The electronic device according to claim 11, characterized in that: One of the cover and the support member has a convex portion extending toward the other of the cover and the support member in a direction substantially perpendicular to the plate surface. The other of the cover and the support member has a recessed portion that fits with the convex portion at a position corresponding to the convex portion.

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