electronic machines

Abstract

To obtain an electronic apparatus equipped with a wireless communication antenna which has a wireless communication function that suppresses the influence of noise generated in the surroundings and has high reception sensitivity.SOLUTION: An electronic apparatus 100 comprises: a first circuit board 10 having a first front surface 16 having a light emitting element 15 and a second front surface 17 having an antenna 14; and a second circuit board 20 having a main control circuit 21, the first circuit board and the second circuit board being connected by a first inter-board connecting member 2, the electronic apparatus being housed inside a metal housing 1 that includes a first surface 4 having an opening 5. The first circuit board 10 has a first front surface 16 disposed along the first surface 4 of the metal housing 1 and adjacent to the first surface 4, and the light emitting element 15 and the antenna 14 are arranged in a manner to overlap the opening in a plan view from a first direction perpendicular to the first surface 4.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to an electronic device equipped with an antenna for wireless communication. [Background technology]

[0002] In recent years, wireless communication technologies such as wireless LAN and Bluetooth (registered trademark), which allow information exchange by sending and receiving radio waves without using cables, have become widespread, and electronic devices with built-in wireless communication antennas have been put to practical use. It is also known to provide a detachable antenna on the exterior of an electronic device in order to add wireless communication functionality with high reception sensitivity (see, for example, Reference 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-243914 Summary of the Invention [Problem to be solved by the invention]

[0004] The detachable patch antenna in Patent Document 1 describes that reception sensitivity can be improved by attaching the detachable patch antenna to an antenna terminal provided on the exterior of an electronic device and aligning the orientation of the patch antenna with the direction of the radio waves to be received. However, when other electronic devices are placed near the antenna, such as when multiple electronic devices are used side by side, there is a problem in that reception sensitivity to noise generated by the other electronic devices also increases.

[0005] The present disclosure has been made in light of the above-mentioned problems, and aims to provide an electronic device that has a wireless communication function with high reception sensitivity and that suppresses the influence of noise generated by other surrounding electronic devices. [Means for solving the problem]

[0006] The electronic device according to the present disclosure includes a first circuit board having a first surface provided with a light-emitting element and a second surface opposite to the first surface provided with an antenna; a second circuit board having a main control circuit; and a first inter-board connecting member connecting the first circuit board and the second circuit board; It is made of metal material, The device is characterized in that it comprises a metal housing that houses a first circuit board and a second circuit board and includes a first surface having an opening, the first circuit board having a first surface that is arranged along and adjacent to the first surface of the metal housing, and the light-emitting element and antenna being arranged so as to overlap with the opening in a plan view from a first direction perpendicular to the first surface. [Effects of the Invention]

[0007] The electronic device according to the present disclosure can suppress the influence of noise generated in the surroundings and can be provided with a wireless communication function with high reception sensitivity. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a circuit block diagram showing a configuration of an electronic device 100 according to a first embodiment. [Figure 2] 1 is a perspective view showing the appearance of an electronic device 100 according to a first embodiment. [Figure 3] 3 is a cross-sectional view taken along the line AA shown in FIG. 2. [Figure 4] 3 is a cross-sectional view taken along the cross-sectional line BB shown in FIG. 2. [Figure 5] 1 is a front view showing the appearance of a circuit board unit 30 according to the first embodiment. [Figure 6] 1 is a perspective view showing the appearance of a circuit board unit 30 according to a first embodiment. [Figure 7] FIG. 5 is an enlarged view of an area C shown in FIG. [Figure 8] 10 is a graph showing the relationship between the electric field strength of a plane electric field wave, the longitudinal length L of the opening 5, and the distance D between the opening antennas. [Figure 9] FIG. 10 is a perspective view showing the appearance of an electronic device 200 according to a second embodiment. [Figure 10]10 is a cross-sectional view taken along the cross-sectional line JJ shown in FIG. 9. [Figure 11] FIG. 10 is a cross-sectional view taken along the cross-sectional line KK shown in FIG. 9. [Figure 12] FIG. 10 is a front view showing a circuit board unit 40 according to a second embodiment. [Figure 13] FIG. 10 is a cross-sectional view showing an electronic device 201 according to a modification of the second embodiment. [Figure 14] 10 is a front view showing a circuit board unit 41 in a modified example of the second embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Embodiment 1 1 is a circuit block diagram showing the configuration of electronic device 100 according to embodiment 1. Electronic device 100 has first circuit board 10 and second circuit board 20, which are housed inside metal housing 1.

[0010] The first circuit board 10 includes a display circuit 11, a setting circuit 12, a wireless circuit 13, and an antenna 14. The second circuit board 20 includes a main control circuit 21, a communication circuit 22, and an external connector 23. The first circuit board 10 and the second circuit board 20 are connected by an inter-board connecting member 2 such as an inter-board connector. Here, the arrows shown in FIG. 1 indicate the direction in which signals are exchanged. The inter-board connecting member 2 is the first inter-board connecting member recited in the claims.

[0011] Here, the electronic device 100 in the first embodiment is, for example, a PCL (Programmable Logic Controller), a servo amplifier, or an inverter. However, the electronic device 100 is not limited to these electronic devices. The electronic device 100 also has a wireless communication function.

[0012] The display circuit 11 provided on the first circuit board 10 includes a light-emitting element 15 such as an LED (Light Emitting Diode). The display circuit 11 may further include a current-limiting resistor that limits the current flowing through the light-emitting element 15, and an LED driver that stably supplies current to the LED that is the light-emitting element 15. Here, the display circuit 11 uses the light of the light-emitting element 15 to allow a user to visually recognize, for example, the operating status of the electronic device 100, the communication status between the electronic device 100 and devices connected thereto, and the operating status of devices connected to the electronic device 100. The light-emitting element 15 will be described later.

[0013] The setting circuit 12 includes an input unit such as a piano switch or a rotary switch. The input unit serves as an external input 3, allowing a user to set the operation and processing of the electronic device 100 via the input unit. Here, it is not essential to include both the display circuit 11 and the setting circuit 12; it is sufficient to include at least one of the display circuit 11 or the setting circuit 12. The input unit will be described later.

[0014] Radio circuit 13 includes, for example, a control circuit having a wireless communication controller IC, a power supply circuit, an oscillator circuit or PLL circuit that generates a carrier wave, an AD conversion circuit or DA conversion circuit, a modulation circuit, a filter, a mixer, an amplifier, or a matching circuit, and performs conversion from a digital signal to a modulated wave and conversion from a modulated wave to a digital signal between main control circuit 21 and antenna 14. Here, radio circuit 13 may be provided on second circuit board 20 instead of first circuit board 10.

[0015] The antenna 14 functions as an energy converter for transmitting an electric signal as a radio wave into space and receiving the radio wave in space as an electric signal. To efficiently supply power to the antenna 14, it is preferable to use a matching circuit provided in the radio circuit 13 to match the input impedance of the antenna 14 with the impedance of the signal source.

[0016] The main control circuit 21 provided on the second circuit board 20 is composed of a control IC such as a CPU (Central Processing Unit), FPGA (Field Programmable Gate Array), or SoC (System on a Chip), and may also include a transmission circuit, a reset circuit, an interrupt circuit, a main memory, etc. The main control circuit 21 is responsible for the calculation, storage, and control of the electronic device 100. It also functions as a circuit that controls the radio circuit 13.

[0017] Here, communication between the main control circuit 21 and the radio circuit 13 is performed by an interface (I / F) such as a serial communication interface (SPI) or a universal asynchronous receiver / transmitter (UART).

[0018] Furthermore, the electronic device 100 in embodiment 1 is not limited to the circuits shown in FIG. 1, and may include other circuits such as a power supply circuit, an inverter circuit, an analog / digital input / output circuit, a video input / output circuit, an audio input / output circuit, a filter circuit, an isolation circuit, and a surge static electricity protection circuit, depending on the functions required of the electronic device 100.

[0019] Next, we will explain the circuit operation of electronic device 100 when it transmits information to an external electronic device using its wireless communication function. The digital signal indicating the information to be transmitted is output as an electrical signal from main control circuit 21, and is modulated to a carrier frequency in accordance with the wireless standard by wireless circuit 13. Next, the digital signal modulated to the carrier frequency is converted from an electrical signal to a radio wave by antenna 14, and the information is transmitted as a radio wave to the external electronic device.

[0020] Next, the circuit operation of electronic device 100 receiving information transmitted from an external electronic device using the wireless communication function will be described. Radio waves indicating the information transmitted from the external electronic device are received by antenna 14, and the radio waves are converted into an electrical signal by antenna 14. Next, the electrical signal converted by antenna 14 is digitized by wireless circuit 13, and transmitted to main control circuit 21 as digital information.

[0021] Here, the carrier frequency according to the wireless standard is the 2.4 GHz band used in wireless LAN and Bluetooth (registered trademark). However, it may be a carrier frequency according to other wireless standards, such as the 3.7 GHz band, 4.5 GHz band, 5 GHz band, or 28 GHz band. Furthermore, in order to support multiple wireless standards, multiple radio circuits 13 and multiple antennas 14 may be provided.

[0022] Furthermore, in addition to the wireless communication function, the electronic device 100 has a wired communication function such as a USB (Universal Serial Bus) or a wired LAN. For example, the electronic device 100 can transmit and receive information to and from an external electronic device using an external connector 23 and a communication circuit 22. The external connector 23 is, for example, a USB connector or an RJ45 connector. A detailed description of the wired communication function will be omitted here.

[0023] Fig. 2 is a perspective view showing the appearance of electronic device 100 in embodiment 1. Fig. 3 shows a cross-sectional view of electronic device 100 shown in Fig. 2 taken along line AA. Fig. 4 shows a cross-sectional view of electronic device 100 shown in Fig. 3 taken along line BB. Fig. 5 shows a front view showing the configuration of circuit board unit 30 in which first circuit board 10 and second circuit board 20 are connected by inter-board connecting member 2. Fig. 6 shows a perspective view showing the configuration of circuit board unit 30.

[0024] 2 to 4, electronic device 100 in embodiment 1 includes circuit board unit 30 in which first circuit board 10 and second circuit board 20 are connected using inter-board connection member 2, and metal housing 1 that houses circuit board unit 30. Metal housing 1 has multiple surfaces including first surface 4, and first surface 4 of metal housing 1 is provided with opening 5. Here, opening 5 in metal housing 1 is shown as a single opening, but this is not limited thereto. In other words, opening 5 in metal housing 1 may be composed of multiple openings.

[0025] The opening 5 is provided so as to overlap with the light-emitting element 15 provided on the first circuit board 10, the input section provided on the first circuit board 10, or both the light-emitting element 15 and the input section, in a plan view from a first direction (Y direction) that is a direction perpendicular to the first surface 4. Here, the input section is not shown. Furthermore, the opening 5 is provided so as to overlap with at least a portion of the antenna 14 provided on the first circuit board 10, in a plan view from the first direction that is a direction perpendicular to the first surface 4.

[0026] 2, a hole is provided on the first surface 4 of the metal housing 1 to match the size of the external connector 23 provided on the second circuit board 20 so as to overlap with the external connector 23 in the first direction, and the external connector 23 is fixed so that a part of the external connector 23 is exposed through the hole in the metal housing. Here, the material of the external connector 23 may be either metallic or non-metallic.

[0027] The opening 5 provided in the metal housing 1 may be filled with a dielectric 6. The dielectric 6 is, for example, resin or glass. Furthermore, it is preferable to use an insulator with a relative dielectric constant of 1 or more as the dielectric 6. By increasing the relative dielectric constant of the insulator, the wavelength of the radio waves can be shortened, and even if the opening 5 is small, the penetration depth of the radio waves into the metal housing 1 can be increased, making it easier to transmit and receive wirelessly. Furthermore, by filling the opening 5 with a dielectric 6 such as resin or glass, it is possible to improve dustproof and waterproof performance.

[0028] Metallic materials such as copper, iron, aluminum, iron alloys, or aluminum alloys are used for the metal housing 1. The thickness of the metal housing 1 is 0.1 mm or more, and preferably 1 mm or more. The metal housing 1 may be a one-piece molded body, or may be formed by combining multiple metal plates.

[0029] The electrical conductivity of metal housing 1 is 1.0x10 6 [S / m] or more, preferably 1.0x10 7 In addition, in an installation environment where electronic device 100 requires magnetic shielding at a frequency of 50 / 60 Hz, it is preferable to use a magnetic metal with high electrical conductivity, such as SPCC, which is mainly composed of iron, or SUS430.

[0030] Furthermore, the thermal conductivity of the metal casing 1 is 1.0 W / (m·K) or more, and preferably 10.0 W / (m·K) or more. The metal casing 1 may also be equipped with piping for passing cooling water therethrough, or with heat dissipation fins to promote heat dissipation to the atmosphere. The metal casing 1 may also be in contact with an external cooler to dissipate heat through heat transfer. The external cooler is not shown here.

[0031] The potential of metal casing 1 is set according to the performance required of electronic device 100. For example, it is set to the same potential as the reference ground of first circuit board 10 and second circuit board 20. However, it is not limited to this, and the potential of metal casing 1 may also be set to the same potential as the frame ground or earth.

[0032] In this way, by using the metal housing 1 as the housing of the electronic device 100, it is possible to prevent electric shock and burns to the user, and to protect the circuit board unit 30 housed in the electronic device 100 from dust and oil droplets generated in the installation environment. Furthermore, by using the metal housing 1, it is possible to improve noise resistance, vibration resistance, impact resistance, and heat dissipation. In particular, since the metal housing 1 is mostly covered with metal, it functions as a shield against electromagnetic noise, and is therefore able to block external noise that may reach the electronic device 100 in the installation environment.

[0033] Furthermore, by DC- or AC-coupling the reference grounds of the metal casing 1 and the circuit board unit 30 therein, it is possible to reduce the impedance of the reference ground, thereby improving the EMC (Electromagnetic Compatibility) performance of the electronic device 100.

[0034] 3 and 4, circuit board unit 30 comprising first circuit board 10 and second circuit board 20 in embodiment 1 is housed in metal housing 1. First circuit board 10 includes a display circuit 11, a wireless circuit 13, and an antenna 14 on a printed circuit board 7. First circuit board 10 is disposed adjacent to first face 4 of metal housing 1, and has first surface 16 facing first face 4 and second surface 17 on the opposite side in a first direction that is perpendicular to first face 4.

[0035] A light-emitting element 15 such as an LED is provided on the first surface 16 of the first circuit board 10. The first surface 16 of the first circuit board 10 is provided adjacent to and along the first face 4, and light from the light-emitting element 15 is emitted to the outside through a dielectric 6 provided in the opening 5. The first surface 16 may also be provided with an input unit instead of the light-emitting element 15, allowing a user to set the operation and processing of the electronic device 100 via the input unit through the opening 5. Furthermore, the first surface 16 of the first circuit board 10 may also be provided with both the light-emitting element 15 and the input unit. The input unit is not shown here.

[0036] A radio circuit 13 and an antenna 14 are provided on the second surface 17 of the first circuit board 10. Here, a configuration in which the radio circuit 13 and the antenna 14 are provided on the first circuit board 10 is shown, but it is also possible to provide only the antenna 14 on the second surface 17 of the first circuit board 10, with the radio circuit 13 being provided on the second circuit board 20. Also, a wireless communication module in which the radio circuit 13 and the antenna 14 are integrally formed may be provided on the second surface 17.

[0037] Furthermore, antenna 14 may be configured with multiple antennas instead of a single antenna, and each may be used for wireless LAN and Bluetooth. Furthermore, antenna 14 may be given directionality so that radio waves for wireless communication can be efficiently transmitted and received through opening 5 in metal casing 1.

[0038] Second circuit board 20 has third surface 24 having main control circuit 21 and fourth surface 25 opposite to the third surface. Second circuit board 20 is disposed, for example, along second surface 9, which is a plane perpendicular to first surface 4 of metal housing 1. In other words, second circuit board 20 is disposed adjacent to second surface 9, which is a plane perpendicular to first surface 4 of metal housing 1, and fourth surface 25 of second circuit board 20 is disposed opposite second surface 9.

[0039] The second circuit board 20 includes a main control circuit 21, a communication circuit 22, and an external connector 23 on a printed circuit board 8. Here, the main control circuit 21 and the communication circuit 22 may be provided on the second circuit board 20 as a single main control IC. Furthermore, the second circuit board 20 includes an external connector 23 at a location adjacent to the first surface 4 of the metal casing 1. Here, the external connector 23 is provided so that a portion of it is exposed from the metal casing 1. As shown in FIGS. 3 to 6, the second circuit board 20 is formed from one printed circuit board 8, but is not limited to this and may be formed from multiple printed circuit boards 8 depending on the circuit scale.

[0040] The first circuit board 10 is connected to the second circuit board 20 using an inter-board connecting member 2 such as an inter-board connector. The inter-board connecting member 2 is not limited to an inter-board connector, and electrodes provided on the first circuit board 10 and the second circuit board 20 may be connected by soldering or by a cable.

[0041] Furthermore, the inter-board connection member 2 is an interface that electrically connects the first circuit board 10 and the second circuit board 20, and signal transmission, power supply, common ground, and the like are performed via the inter-board connection member 2. Multiple inter-board connection members 2 may be provided, and an inter-board connection member 2 may be provided for each purpose, such as for signal, power, and ground connection. Furthermore, for example, a metal spacer or a metal screw may be used as the inter-board connection member 2 for ground connection. This can improve the strength of the connection and reduce the impedance between the grounds of the first circuit board 10 and the second circuit board 20.

[0042] The printed circuit boards 7 and 8 used in the first circuit board 10 and the second circuit board 20 are made of materials such as glass fiber reinforced epoxy resin, phenolic resin, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), etc. The printed circuit boards may also be made of ceramics such as aluminum oxide, aluminum nitride, and silicon carbide.

[0043] Furthermore, the printed circuit boards 7 and 8 used in the first circuit board 10 and the second circuit board 20 may include two or more conductor layers that form circuit wiring, and the circuit wiring may be formed on the surface and inside the printed circuit boards 7 and 8. The circuit wiring is formed from a conductive material, such as copper, nickel, gold, aluminum, silver, tin, or an alloy thereof. The thickness of the circuit wiring is 1 μm or more and 2000 μm or less. Illustration of the circuit wiring is omitted here.

[0044] In electronic device 100 according to the first embodiment, first circuit board 10 is disposed inside metal housing 1, adjacent to first surface 4 of metal housing 1, with first surface 16 aligned along first surface 4. Antenna 14 is provided on second surface 17 opposite first surface 16, and is disposed so that at least a portion of antenna 14 overlaps with opening 5 provided in metal housing 1 in a first direction (Y direction) that is perpendicular to first surface 4.

[0045] The shorter the distance from opening 5 in the first direction, the higher the reception sensitivity of antenna 14 for wireless communication with external electronic devices. Furthermore, as shown in Figures 3 to 6, in electronic device 100 according to the first embodiment, antenna 14 is provided on second surface 17 of first circuit board 10, and at least printed circuit board 7 of first circuit board 10 is provided between antenna 14 and opening 5 of metal housing 1.

[0046] Here, the circuit wiring provided on the printed circuit board 7 of the first circuit board 10 is formed of a conductive material such as copper foil, and therefore may block part of the radio waves used for wireless communication with external electronic devices, degrading transmission and reception performance. Therefore, by reducing the circuit wiring provided on the printed circuit board 7, it is possible to suppress deterioration of transmission and reception performance. In other words, by reducing the wiring ratio of the circuit wiring provided on the printed circuit board 7, it is possible to suppress deterioration of transmission and reception performance.

[0047] For example, the wiring ratio of the circuit wiring of the printed circuit board 7 in the first circuit board 10 is lower than the wiring ratio of the printed circuit board 8 in the second circuit board 20 including the main control circuit 21. This makes it possible to suppress deterioration of transmission and reception performance due to the radio waves used for wireless communication being blocked by the circuit wiring.

[0048] Furthermore, by not providing circuit wiring in the area of ​​the printed circuit board 7 that overlaps with the antenna 14 in a plan view in the first direction perpendicular to the first surface 4 of the metal casing 1, radio waves used for wireless communication are not blocked by the circuit wiring, and deterioration of transmission and reception performance can be suppressed. Also, by not providing the light-emitting element 15 or the input unit in the area of ​​the printed circuit board 7 that overlaps with the antenna 14 in a plan view in the first direction, deterioration of transmission and reception performance can be suppressed.

[0049] As shown in FIGS. 3 and 4 , electronic device 100 in the first embodiment has opening 5 in metal casing 1. Opening 5 has, for example, a rectangular shape, and the longer the length of the long side, which is the length in the longitudinal direction, the easier it is for radio waves used for wireless communication to penetrate into metal casing 1, and the higher the radio wave transmission and reception performance of antenna 14. In other words, the longer the length of opening 5, which is the length in the longitudinal direction, the better the radio wave transmission and reception performance can be maintained even if antenna 14 and opening 5 are farther apart in the first direction. Here, the length of the short side of opening 5 needs only to be 1 mm or more, and the short side length of opening 5 has little effect on the radio wave transmission and reception performance.

[0050] Although the shape of the opening 5 is shown as a rectangle in the example, it is not limited to this and may be an oval or a rectangle with rounded corners. Furthermore, although the opening 5 in the metal housing 1 is shown as a single opening in Figures 3 and 4, this is not limited to this. In other words, the opening 5 in the metal housing 1 may be composed of multiple openings.

[0051] 7 and 8, a simulation result of propagating a 2.4 GHz electric field plane wave used in wireless LAN and Bluetooth through a metal housing 1 constituting electronic device 100 will be described. Fig. 7 is an enlarged view of region C surrounded by a dashed line in Fig. 4. Here, the dielectric 6 filled in opening 5 is not shown.

[0052] 7, the longitudinal length, which is the length of the long side of the opening 5 of the metal casing 1, is defined as L. Furthermore, an imaginary plane E (two-dot dashed line) including the first surface 4 of the metal casing 1 and the opening 5 provided in the first surface is defined as E, and the inter-aperture antenna distance, which is the distance from the imaginary plane E to the antenna 14 in the first direction (Y direction) perpendicular to the first surface 4 of the metal casing 1, is defined as D. Here, if the opening 5 of the metal casing 1 is made up of multiple openings, the longitudinal length of each opening is defined as L. Here, the longitudinal length L of the opening 5 is set so that the opening 5 fits within the first surface 4 of the metal casing 1.

[0053] FIG. 8 is a graph showing the relationship between the electric field strength of a 2.4 GHz band electric field plane wave, the longitudinal length L, which is the length in the long side direction of the opening 5, and the distance D between the opening antennas. Dashed line F indicates an electric field strength of 70%, and region G, which ends at dashed line F, indicates an area where the electric field strength is 70% or more. Furthermore, dashed-dotted line H is a straight line indicating L / D=1. This shows that region G overlaps with the area where L / D≧1. In other words, when the longitudinal length L of the opening 5 and the distance D between the opening antennas satisfy L / D≧1, the electric field strength at antenna 14 is 70% or more.

[0054] Here, good radio wave transmission and reception performance can be obtained by wireless communication if the electric field strength at antenna 14 is 70% or more. That is, by providing opening 5 in metal casing 1 and antenna 14 so as to satisfy L / D≧1, electronic device 100 equipped with wireless communication functions and high reception sensitivity can be obtained.

[0055] Next, the effects of electronic device 100 in embodiment 1 will be described. Electronic device 100 has first circuit board 10 and second circuit board 20, which are housed inside metal housing 1. First circuit board 10 has first surface 16 that includes light-emitting element 15 of display circuit 11 and an input section of setting circuit 12, or light-emitting element 15 and the input section. First circuit board 10 also includes antenna 14 on second surface 17 opposite first surface 16.

[0056] By using a metal housing 1 as the housing of the electronic device 100 and storing the first circuit board 10 and the second circuit board 20 inside the metal housing 1, it is possible to prevent electric shock and burns to the user and to protect the circuit board unit 30 stored inside the electronic device 100 from dust and oil droplets generated in the installation environment. Furthermore, by using the metal housing 1, it is possible to improve noise resistance, vibration resistance, impact resistance, and heat dissipation. In particular, since the metal housing 1 is mostly covered with metal, it functions as a shield against electromagnetic noise, and is therefore able to block external noise that may reach the electronic device 100 in the installation environment.

[0057] Moreover, first circuit board 10 is provided so that first surface 16 is adjacent to and along first face 4 of metal housing 1. In other words, first circuit board 10 is disposed so that it is adjacent to first face 4 of metal housing 1 and first surface 16 faces first face 4.

[0058] Here, opening 5 of metal casing 1 is provided so as to overlap with light-emitting element 15 provided on first circuit board 10, an input section provided on first circuit board 10, or light-emitting element 15 and the input section, in plan view from a first direction (Y direction) that is a direction perpendicular to first surface 4. Furthermore, opening 5 is provided so as to overlap with at least a portion of antenna 14 provided on first circuit board 10, in plan view from the first direction. Here, light-emitting element 15, the input section, or light-emitting element 15 and the input section are arranged closer to opening 5 than antenna 14.

[0059] Furthermore, in the electronic device 100 of embodiment 1, the longitudinal length L of the opening 5 in the metal housing 1 and the aperture-antenna distance D, which is the distance from the antenna 14 to an imaginary plane E including the first surface 4 and the opening 5 provided on the first surface in a first direction (Y direction) perpendicular to the first surface 4 of the metal housing 1, are set so as to satisfy L / D≧1, thereby achieving good radio wave transmission and reception performance via wireless communication.

[0060] This makes it possible to obtain electronic device 100 that is capable of suppressing the influence of noise generated in the surroundings and has a wireless communication function with high reception sensitivity.

[0061] Embodiment 2 Next, electronic device 200 according to embodiment 2 will be described. Note that in embodiment 2, only the parts of the configuration that are different from embodiment 1 will be described. Furthermore, the same or corresponding configurations as embodiment 1 will be designated by the same reference numerals in the drawings, and the description thereof will be omitted. Here, electronic device 200 differs from electronic device 100 according to embodiment 1 in the configuration of first circuit board 10 and the arrangement of first circuit board 10 within metal casing 1.

[0062] Fig. 9 is a perspective view showing the appearance of electronic device 200 in embodiment 2. Fig. 10 shows a cross-sectional view of electronic device 200 shown in Fig. 9 at part JJ. Fig. 11 shows a cross-sectional view of electronic device 200 shown in Fig. 9 at part KK. Fig. 12 is a front view showing the configuration of circuit board unit 40 in which first circuit board 10 and second circuit board 20 are connected by inter-board connecting member 2A.

[0063] 9 to 11, electronic device 200 in embodiment 2 includes circuit board unit 40 in which first circuit board 10 and second circuit board 20 are connected by inter-board connecting member 2A, and metal housing 1 that houses circuit board unit 40. Metal housing 1 has multiple faces including first face 4, and first face 4 of metal housing 1 has opening 5 formed therein.

[0064] 9 to 11, first circuit board 10 includes light-emitting element 15, wireless circuit 13, and antenna 14 on printed circuit board 7, and has first surface 16 and second surface 17 opposite first surface 16. Second circuit board 20 includes main control circuit 21, communication circuit 22, and external connector 23 on printed circuit board 8, and has third surface 24 and fourth surface 25 opposite third surface 24. Here, circuit board unit 40 is disposed so that second surface 17 of first circuit board 10 and third surface 24 of second circuit board 20 face each other, and are connected by inter-board connecting member 2A.

[0065] First circuit board 10 is disposed such that first surface 16 and second surface 17 are aligned along a first direction (Y direction) that is perpendicular to first face 4 of metal casing 1. First circuit board 10 further has edge 18 connecting first surface 16 and second surface 17, with at least a portion of edge 18 disposed adjacent to opening 5.

[0066] The second circuit board 20 is disposed, for example, along the second surface 9, which is a surface perpendicular to the first surface 4 of the metal housing 1. In other words, the second circuit board 20 is disposed adjacent to the second surface 9, which is a surface perpendicular to the first surface 4 of the metal housing 1, and the fourth surface 25 of the second circuit board 20 is disposed opposite the second surface 9.

[0067] Light-emitting elements 15 such as LEDs of a display circuit 11 are provided on a first surface 16 of the first circuit board 10. An input section of a setting circuit 12 may be provided instead of the light-emitting elements 15 of the display circuit 11. Furthermore, both the light-emitting elements 15 and the input section may be provided. The light-emitting elements 15, the input section, or both the light-emitting elements 15 and the input section are provided so as to overlap with the opening 5 in a plan view from a first direction (Y direction) that is perpendicular to the first surface 4.

[0068] Here, the light-emitting element 15 is disposed near the edge 18 adjacent to the opening 5, and light from the light-emitting element 15 is emitted to the outside through the dielectric 6 provided in the opening 5. The input unit is also disposed near the edge 18 adjacent to the opening 5, and the user can set the operation and processing of the electronic device 100 via the input unit through the opening 5. The input unit is not shown here.

[0069] A radio circuit 13 and an antenna 14 are provided on the second surface 17 of the first circuit board 10. Here, a configuration in which the radio circuit 13 and the antenna 14 are provided on the first circuit board 10 is shown, but only the antenna 14 may be provided on the second surface 17 of the first circuit board 10, and the radio circuit 13 may be provided on the second circuit board 20. Alternatively, a wireless communication module in which the radio circuit 13 and the antenna 14 are integrally formed may be provided on the second surface 17. Here, at least a portion of the antenna 14 is provided so as to overlap with the opening 5 in a plan view from a first direction that is a direction perpendicular to the first surface 4 of the metal housing 1.

[0070] The closer antenna 14 is to opening 5, the better, and it is advisable to place antenna 14 near the edge of first circuit board 10 adjacent to opening 5. In electronic device 100 of embodiment 2, first surface 16 and second surface 17 of first circuit board 10 are placed along a direction perpendicular to first face 4 of metal casing 1, so antenna 14 can be placed closer to opening 5 than in electronic device 100 of embodiment 1.

[0071] Furthermore, similar to embodiment 1, electronic device 200 of embodiment 2 is configured such that the longitudinal length L of opening 5 in metal housing 1 and the aperture-antenna distance D, which is the distance from antenna 14 to an imaginary plane E including first surface 4 of metal housing 1 and opening 5 provided in the first surface in a first direction (Y direction) perpendicular to the first surface, satisfy L / D≧1.

[0072] Fig. 13 shows the same cross-sectional view as Fig. 11 of embodiment 2, of electronic device 201 according to a modification of embodiment 2, in which inter-board connecting member 2B is added in addition to inter-board connecting member 2A connecting first circuit board 10 and second circuit board 20. Fig. 14 is a front view showing the appearance of circuit board unit 41 according to the modification of embodiment 2. Inter-board connecting member 2A is the first inter-board connecting member recited in the claims, and inter-board connecting member 2B is the second inter-board connecting member recited in the claims.

[0073] 13 and 14, electronic device 201 according to a modification of the second embodiment uses inter-board connecting member 2B in addition to inter-board connecting member 2A to connect first circuit board 10 and second circuit board 20. For example, inter-board connecting member 2A may be used for signals and power, and inter-board connecting member 2B may be used for ground connection, and different inter-board connecting members 2 may be provided for different purposes. Furthermore, for example, metal spacers or metal screws may be used for ground connection. This improves the strength of the connection and reduces the impedance between the grounds of first circuit board 10 and second circuit board 20.

[0074] Next, the effects of electronic device 200 according to the second embodiment and electronic device 201 according to a modification of the second embodiment will be described. In electronic device 200 and electronic device 201, first circuit board 10 is arranged so that first surface 16 and second surface 17 of first circuit board 10 are aligned along a direction perpendicular to first face 4 of metal casing 1. As a result, antenna 14 is arranged near edge 18 of first circuit board 10 adjacent to opening 5, and thus antenna 14 can be arranged closer to opening 5 than in electronic device 100 according to the first embodiment.

[0075] As a result, it is possible to obtain the electronic device 200 or the electronic device 201 having a wireless communication function with higher reception sensitivity than the electronic device 100 of the first embodiment. [Explanation of symbols]

[0076] 1 Metal housing, 2, 2A, 2B Inter-board connecting member, 3 External input, 4 First surface, 5 Opening, 6 Dielectric, 7, 8 Printed circuit board, 9 Second surface, 10 First circuit board, 11 Display circuit, 12 Setting circuit, 13 Wireless circuit, 14 Antenna, 15 Light-emitting element, 16 First surface, 17 Second surface, 18 Edge portion, 20 Second circuit board, 21 Main control circuit, 22 Communication circuit, 23 External connector, 24 Third surface, 25 Fourth surface, 30, 40, 41 Circuit board unit, 100, 200, 201 Electronic device.

Claims

1. a first circuit board having a first surface with a light emitting element thereon and a second surface opposite the first surface with an antenna; a second circuit board including a main control circuit; a first inter-board connecting member that connects the first circuit board and the second circuit board; a metal housing formed of a metal material, housing the first circuit board and the second circuit board, and including a first surface having an opening; the first circuit board is disposed such that the first surface is adjacent to and along the first surface of the metal housing; The electronic device is configured such that the light-emitting element and the antenna overlap with the opening in a plan view from a first direction perpendicular to the first surface.

2. a first circuit board having a first surface provided with an input section capable of receiving an input from an external device, and a second surface opposite to the first surface provided with an antenna; a second circuit board including a main control circuit; a first inter-board connecting member that connects the first circuit board and the second circuit board; a metal housing formed of a metal material, housing the first circuit board and the second circuit board, and including a first surface having an opening; the first circuit board is disposed such that the first surface is adjacent to and along the first surface of the metal housing; The electronic device, wherein the input unit and the antenna are arranged to overlap with the opening in a plan view from a first direction perpendicular to the first surface.

3. a first circuit board having a first surface with a light emitting element thereon and a second surface opposite the first surface with an antenna; a second circuit board including a main control circuit; a first inter-board connecting member that connects the first circuit board and the second circuit board; a metal housing that houses the first circuit board and the second circuit board and includes a first surface having an opening; the first circuit board is disposed along the second circuit board with the second surface facing the second circuit board; The electronic device is configured such that the light-emitting element and the antenna overlap with the opening in a plan view from a first direction perpendicular to the first surface.

4. a first circuit board having a first surface provided with an input section capable of receiving an input from an external device, and a second surface opposite to the first surface provided with an antenna; a second circuit board including a main control circuit; a first inter-board connecting member that connects the first circuit board and the second circuit board; a metal housing that houses the first circuit board and the second circuit board and includes a first surface that has an opening, the first circuit board is disposed along the second circuit board with the second surface facing the second circuit board; The electronic device, wherein the input unit and the antenna are arranged to overlap with the opening in a plan view from a first direction perpendicular to the first surface.

5. The antenna 5. The electronic device according to claim 1, wherein a longitudinal length L of the opening and an aperture-antenna distance D, which is a distance from the opening to the antenna, are set so as to satisfy L / D≧1.

6. the second circuit board has a third surface including the main control circuit and a fourth surface opposite the third surface; the metal housing has a second surface perpendicular to the first surface; The electronic device according to claim 3 , wherein the fourth surface of the second circuit board is disposed along and adjacent to the second surface.

7. The electronic device according to claim 1 , further comprising a second inter-board connecting member that connects the first circuit board and the second circuit board.

8. The electronic device according to claim 1 , wherein a wiring ratio of the circuit wiring of the first circuit board is lower than a wiring ratio of the circuit wiring of the second circuit board.

9. The electronic device according to claim 1 , wherein the opening is filled with an insulator having a relative dielectric constant of 1 or more.

10. An electronic device as described in claim 1, wherein the first surface and the first face are opposite each other.

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