JP2012161011A - Electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system which stabilizes the receiver sensitivity of an antenna part without increasing an area of an antenna substrate and suppresses the deterioration of the receiver sensitivity of the antenna part by forming a structure which makes noise in an apparatus body less likely to be conducted to the antenna part.SOLUTION: A GPS antenna module 5 is mounted on an electronic apparatus. The GPS antenna module 5 includes an antenna part 5A provided on a front surface of an antenna substrate 39 and a control circuit 44 provided at a rear surface of the antenna substrate 39 through a ground 45 and controlling the driving of the antenna part 5A. In the antenna part 5A, an antenna electrode 47 is laminated on a counter electrode 48 provided on the front surface of the antenna substrate 39 through a dielectric body 43. A top chassis 41 holding a release button is electrically connected with the counter electrode 48, and a top chassis 40 is electrically connected with a ground 45 and a power supply circuit mounted on a main substrate.

Description

  The present invention relates to an electronic device such as a digital camera equipped with an antenna module such as GPS.

  It is known to provide a GPS antenna module in a digital camera. In such a digital camera, the position where the camera exists is detected based on the positioning signal received by the GPS antenna module (Patent Document 1).

JP 2003-315890 A

  As shown in FIG. 11, a GPS antenna module mounted on a digital camera or the like is generally provided with an antenna unit 100 on the front surface side of an antenna substrate 139 and drives the antenna unit 100 on the rear surface side of the antenna substrate 139. A control circuit 144 for controlling is provided.

  In the antenna unit 100, an antenna electrode 147 is stacked on a counter electrode 148 provided on the surface side of the antenna substrate 139 via a dielectric 143 such as ceramic, and receives a signal from a GPS satellite.

  In such a GPS antenna module, the signal generated between the antenna electrode 147 and the counter electrode 148 becomes more stable as the area of the counter electrode 148 is larger. Further, by connecting the ground 145 of the signal processing unit of the control circuit 144 that amplifies the generated signal and the counter electrode 148 in the vicinity of the input of the signal processing unit, a noise signal enters the antenna unit 100 from the ground 145 side. Can be prevented.

  By the way, in order to increase the area of the counter electrode 148, it is conceivable to increase the area of the antenna substrate 139. However, the size of the antenna substrate 139 is limited with the downsizing of a digital camera or the like.

  Therefore, as shown in FIG. 11, the metal body 140 is electrically connected to the counter electrode 148, thereby increasing the apparent area of the counter electrode 148, thereby increasing the area of the antenna substrate 139. The reception sensitivity of the antenna unit 100 is stabilized.

  However, since the ground 145 of the signal processing unit is connected to the ground of the main board of the camera body, the counter electrode 148 is connected to the ground of the main board through the pattern on the antenna board 139 and the metal body 140. .

  For this reason, noise generated in a power supply circuit or the like mounted on the main board is conducted to the counter electrode 148 through the metal body 140 and the antenna board 139. As a result, the ground potential of the counter electrode 148 is disturbed by noise, the potential on the ground 145 side of the input unit of the signal processing unit connected to the antenna unit 100 becomes unstable, and the reception sensitivity of GPS radio waves at the antenna unit 100 Decreases.

  Therefore, the present invention stabilizes the reception sensitivity of the antenna unit without increasing the area of the antenna substrate, and suppresses a decrease in the reception sensitivity of the antenna unit by making a structure in which noise in the device main body is difficult to conduct to the antenna unit. The purpose is to provide a mechanism to do this.

  In order to achieve the above object, an electronic device of the present invention is provided with an antenna substrate, an antenna portion provided on the front surface side of the antenna substrate, and a back surface side of the antenna substrate via a ground. An antenna module including a control circuit for controlling driving, and the antenna unit is an electronic device in which an antenna electrode is stacked on a counter electrode provided on a surface side of the antenna substrate via a dielectric. A first metal body electrically connected to the counter electrode, and a second metal body electrically connected to the ground and electrically connected to a power supply circuit mounted on the main board. And.

  According to the present invention, the reception sensitivity of the antenna unit can be stabilized without increasing the area of the antenna substrate, and noise in the device body is difficult to conduct to the antenna unit. A decrease in reception sensitivity can be suppressed.

(A) is the external appearance perspective view which looked at the digital camera which is 1st Embodiment of the electronic device of this invention from the front side, (b) is the external appearance perspective view which looked at the digital camera shown to (a) from the back side. is there. FIG. 2 is an exploded perspective view of the digital camera shown in FIG. It is the disassembled perspective view which looked at FIG. 2 from the back side. It is a disassembled perspective view for demonstrating a GPS antenna module. It is the disassembled perspective view seen from the back side of FIG. It is sectional drawing which shows typically the attachment structure of a GPS antenna module and a top chassis. It is a figure which shows the principal part of the attachment structure of a GPS antenna module and a top chassis. It is a perspective view of the assembly of a top chassis, a main chassis, and a main board. In the digital camera which is 2nd Embodiment of the electronic device of this invention, it is a figure which shows the attachment part of the main chassis in a main board | substrate. It is a perspective view which shows the structure of the attachment part of a GPS antenna module in the digital camera which is 3rd Embodiment of the electronic device of this invention. It is a figure for demonstrating the conventional GPS antenna module.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1A is an external perspective view of a digital camera that is a first embodiment of an electronic apparatus according to the present invention as seen from the front side, and FIG. 1B is a diagram of the digital camera shown in FIG. FIG.

  As shown in FIG. 1A, the digital camera of this embodiment is provided with a zoom lens barrel 2 on the front side of the camera body 1, and a pop-up strobe unit on the upper surface of the camera body 1. 3 and a release button 4 are provided. A zoom lever 35 is provided around the release button 4, and the exterior of the GPS antenna module 5 protrudes between the zoom lever 35 and the flash unit 3.

  As shown in FIG. 1B, a display 6 such as a liquid crystal, a power button 7, a mode dial 8, and an operation button group 9 are provided on the back side of the camera body 1. A connector lid 10 that covers a connector for an external output cable (not shown) is provided on the right side surface of the camera body 1 when viewed from the back side so as to be opened and closed.

  2 is an exploded perspective view of the digital camera shown in FIG. 1A, and FIG. 3 is an exploded perspective view of FIG. 2 viewed from the back side.

  As shown in FIGS. 2 and 3, the front cover 11 forms an exterior on the front side and the top side of the camera body 1. The front cover 11 incorporates a release unit including the release button 4, zoom lever 35, top substrate 37, and top chassis 41 and a GPS antenna module 5.

  On the top substrate 37, electrical contacts corresponding to the release button 4 and the zoom lever 35, a stereo microphone R-side microphone 38, a speaker 36, and a connector for an antenna substrate 39 (see FIG. 4) are mounted. The top substrate 37 is provided with a connector for connecting to the main substrate 13. The top substrate 37 is fixed to the front cover 11 with screws or the like while being positioned and fixed to the top chassis 41.

  A connector for connecting to the top substrate 37 and the GPS antenna module 5 are incorporated in the antenna substrate 39. The antenna substrate 39 is attached so as to partially overlap the top chassis 41 and is fixed to the top chassis 41 with screws or the like.

  The top chassis 40 is attached so that a part of the antenna substrate 39 overlaps, and the top chassis 40 is fixed to the front cover 11 with screws or the like.

  The top chassis 40 and the top chassis 41 are connected to the main chassis 42 by screws or the like so as to have the same potential as the ground of the entire camera body 1, and the main chassis 42 is connected to the ground of the main board 13.

  On the rear cover 12, a display 6, a power button 7, a mode dial 8, an operation button group 9, and the like are arranged. The signal lines of the display 6 and the backlight signal lines of the display 6 are wired to the LCD substrate 14 and the backlight substrate 15, respectively, and connected to the connector of the main substrate 13.

  The signal line of the mode dial 8 is wired to the mode dial board 16 and connected to the connector of the main board 13. The signal line of the jog dial of the operation button group 9 is wired to the operation system board 17 and connected to the connector of the main board 13.

  The front cover 11 and the rear cover 12 are fixed to each other by a locking claw (not shown), and fixed to a structure such as the battery box 18 or the main chassis 42 by screws or the like.

  The main board 13 is fixed to the battery box 18 via a main chassis 42 with screws or the like. On the main board 13, a card slot 19, an HDMI connector 20, a power switch 21, a lid detection switch 22 for the battery box 18, a system circuit component 23, and a power circuit component 24 are mounted. The drive control of the entire digital camera is performed by the system circuit component 23 mounted on the main board 13.

  A battery box 18 for inserting a battery is disposed on the left side of the lens barrel 2 when the camera body 1 is viewed from the front side. The power of the camera is supplied by electrically connecting a battery connector (not shown) mounted on the connection system board 25 above the battery box 18 and a battery (not shown). A strap attachment member 26 is attached to the side surface of the battery box 18. The battery box 18 is fixed to the lens barrel 2 with screws or the like.

  A composite connector 27 for connecting a USB cable, an AV cable, or the like is mounted on the connection system board 25. In addition, AF auxiliary light 28 is mounted on the connection system substrate 25. The connection system substrate 25 is electrically connected to the connector of the main substrate 13 at the tip terminal portion.

  A strobe unit 3 is fixed with screws or the like on the right side of the lens barrel 2 when the camera body 1 is viewed from the front side. In the strobe unit 3, a main controller (not shown), a xenon tube (not shown), and a strobe board 29 are connected by a cable.

  The trigger substrate 30 is connected to the strobe substrate 29 by soldering. By supplying a voltage to the trigger coil (not shown) through the trigger substrate 30, the xenon tube emits light. The strobe board 29 is connected to the main board 13 by an optical system board 31.

  The strobe unit 3 is provided with a stereo microphone L-side microphone 32, and the L-side microphone 32 is mounted on a microphone substrate 33. The microphone substrate 33 is connected to the connector of the main substrate 13 through the back surface of the lens barrel 2.

  A sensor (not shown) is disposed on the rear surface of the lens barrel 2, and the sensor captures image information that has passed through the lens of the lens barrel 2. The sensor is mounted on the image system board 34, and the image system board 34 is connected to the main board 13 by a connector.

  Next, the GPS antenna module 5 will be described with reference to FIGS.

  4 is an exploded perspective view for explaining the GPS antenna module 5, FIG. 5 is an exploded perspective view seen from the back side of FIG. 4, and FIG. 6 is a schematic view of a mounting structure between the GPS antenna module 5 and the top chassis 40, 41. FIG. FIG. 7 is a view showing the main part of the mounting structure of the GPS antenna module 5 and the top chassis 40, 41, and FIG. 8 is a perspective view of the assembly of the top chassis 40, the main chassis 42, 46 and the main board 13.

  4 to 7, the GPS antenna module 5 includes an antenna unit 5 </ b> A provided on the front surface side of the antenna substrate 39, and a control circuit 44 that controls driving of the antenna unit 5 </ b> A on the back surface side of the antenna substrate 39. Is provided via a ground 45.

  In the antenna unit 5A, an antenna electrode 47 is laminated on a counter electrode 48 provided on the surface side of the antenna substrate 39 via a dielectric 43 such as ceramic, and receives a signal from a GPS satellite. The dielectric 43 increases the impedance between the antenna electrode 47 and the counter electrode 48 and obtains a larger voltage. Therefore, it is possible to amplify and receive a signal from a GPS satellite. The counter electrode 48 is used as a ground electrode for stabilizing the reception of the antenna unit 5A.

  The control circuit 44 is covered with a shield case, and a signal from the control circuit 44 is output to the main board 13 via the top board 37 from a connector arranged on the control circuit 44 side of the antenna board 39. The control circuit 44 also includes an amplifier 55 that amplifies signals received from GPS satellites and signals from the control circuit 44.

  The top chassis 40 is electrically connected to the ground 45 on the control circuit 44 side by screws 53. The ground 45 on the control circuit 44 side and the counter electrode 48 are connected to the front and back of the antenna substrate 39 by through holes provided in the antenna substrate 39. The top chassis 40 is electrically connected to the main chassis 42 by screws. Here, the top chassis 40 corresponds to an example of a second metal body of the present invention.

  The main chassis 42 is electrically connected to the ground pattern on the surface layer of the main board 13. Thereby, the GPS antenna module 5 is mechanically coupled to the main chassis 42 and is electrically connected to the ground of the camera body 1.

  Further, the ground pattern on the surface layer of the main board 13 opposite to the main chassis 42 is connected so as to be in contact with the main chassis 46, and the main chassis 46 is electrically connected to the main board 13 and the main chassis 42 by screws. It is connected to the.

  By the way, the power supply circuit 24 on the main board 13 generates noise that adversely affects the GPS antenna module 5. Noise generated from the power supply circuit 24 is conducted through the ground pattern on the surface layer of the main board 13 and is conducted from the main chassis 46 to the main chassis 42 through screws. The noise conducted to the main chassis 42 is further conducted to the ground 45 on the control circuit 44 side of the antenna substrate 39 via the screws and the top chassis 40.

  However, since the antenna unit 5A is disposed on the opposite side across the control circuit 44 side and the antenna substrate 39, conduction noise that is a high frequency is less likely to be conducted to the antenna unit 5A due to its straightness. Thereby, the ground potential of the counter electrode 48 is stabilized, and the reception sensitivity of the GPS antenna module 5 is stabilized.

  The top chassis 41 that holds the release button 4 via the top substrate 37 is electrically connected to the counter electrode 48 disposed on the antenna portion 5A side of the antenna substrate 39 by screws 54. When the top chassis 41 is electrically connected to the counter electrode 48 of the antenna substrate 39, the area of the ground potential facing the antenna electrode 47 is larger than the area of the antenna electrode 47. Here, the top chassis 41 corresponds to an example of the first metal body of the present invention.

  A radio wave signal 56 transmitted from the GPS satellite reaches the antenna electrode 47 and also reaches the top chassis 41. The speed of the radio wave is the same as the speed of the electrical signal transmitted through the electrical conductors such as the top chassis 41 and the counter electrode 48.

  Therefore, referring to FIG. 6, the signal 56 that has reached the top chassis 41 that is away from the antenna electrode 47 is the distance of the distance / the length of the conductor from the receiving portion to the opposing portion of the antenna electrode 47. Be late. Therefore, a potential corresponding to the time-shifted signal 56 is generated between the antenna electrode 47 and the counter electrode 48.

  Since the GPS radio wave has a wavelength of several tens of centimeters, a phase difference that can be sufficiently detected between both poles can be generated even with an antenna portion of several centimeters. Detecting a wavelength of several tens of centimeters with a phase difference of several centimeters is a process of counting the number of signals while calculating the differential value of the signals. Therefore, the larger the phase, the greater the number of radio waves / GPS satellites It becomes easy to measure the distance.

  Further, since the top chassis 41 is a relatively long member, a signal 56 having a time lag between a portion near the screw 54 close to the antenna electrode 47 and a portion far from the portion is added and averaged. It becomes. As a result, the steepness as a signal is lost, and the change in potential due to the signal of the counter electrode 48 becomes smaller than the change in potential generated in the antenna electrode 47. For this reason, the potential difference between the counter electrode 48 and the antenna electrode 47 can be easily identified, and reception sensitivity is improved.

  The reception sensitivity of the GPS antenna module 5 includes a signal 56 that reaches the antenna electrode 47 from the GPS satellite, and a signal 56 that reaches the antenna unit 5A from the GPS satellite through the top chassis 41, the screw 54, and the counter electrode 48. The larger the phase difference 57 is, the higher it is.

  Here, as described above, since the area that becomes the ground potential increases facing the antenna electrode 47, the phase difference 57 between the antenna electrode 47 and the counter electrode 48 increases, and the reception sensitivity of the GPS antenna module 5 increases. improves. Since the top chassis 41 is not directly electrically connected to the main board 13 on which the power circuit 24 is mounted, the top chassis 41 is not affected by noise conducted from the power circuit 24 through each chassis.

  Further, as shown in FIG. 8, a plurality of bent portions and throttle portions are formed in the main chassis 42 and the top chassis 40, which are conductive paths for noise generated in the power supply circuit 24.

  For example, in the vicinity of the portion of the main chassis 42 that is connected to the main board 13 by screws, the main chassis 42 bent 90 degrees from the first surface of the main chassis 42 by the first bent portion 42 a of the main chassis 42. A second surface is formed.

  The shape of the second surface of the main chassis 42 is narrowed by the first narrowed portion 42b of the main chassis 42, and further bent by 90 degrees from the second surface of the main chassis 42 by the second bent portion 42c of the main chassis 42. A third surface of the main chassis 42 is formed.

  The shape of the third surface of the main chassis 42 is restricted by the second restricting portion 42d of the main chassis 42, and further bent by 90 degrees from the third surface of the main chassis 42 by the third bent portion 42e of the main chassis 42. A fourth surface of the main chassis 42 is formed.

  On the fourth surface of the main chassis 42, the fifth surface of the main chassis 42 is formed by the fourth bent portion 42f of the main chassis 42 bent in a crank shape.

  On the fifth surface of the main chassis 42, a sixth surface of the main chassis 42 bent by 90 degrees from the fifth surface of the main chassis 42 is formed by the fifth bent portion 42 g of the main chassis 42.

  On the sixth surface of the main chassis 42, the connecting portion 42h of the main chassis 42 and the connecting portion 40a of the top chassis 40 are mechanically and electrically connected via screws.

  The shape of the first surface of the top chassis 40 where the connecting portion 40a is disposed is narrowed by the narrowed portion 40b of the top chassis 40, and further, the bent portion 40c of the top chassis 40 is 90 degrees from the first surface of the top chassis 40. A bent second surface is formed.

  On the second surface of the top chassis 40, the connecting portion 40d of the top chassis 40 and the antenna substrate 39 are connected by screws 53 and further fixed to the front cover 11 by screws.

  Conductive noise, which is a high frequency, has a high degree of straightness, and an electric signal is emitted as a radio wave at the bent portion of the chassis, so that conduction of noise as an electric signal is suppressed. As a result, noise generated in the power supply circuit 24 is not easily transmitted to the GPS antenna module 5, and a decrease in reception sensitivity of the GPS antenna module 5 can be suppressed.

  It should be noted that high-frequency current is emitted into the air instead of electric current when the circuit conductor is bent or a protrusion or constriction is provided on the circuit conductor. For this reason, in order to avoid that the radio wave emitted in the air is input to the antenna electrode 47 as noise, it is preferable that the electrical connection portion such as the chassis has a shape as simple as possible.

  As described above, in this embodiment, the antenna electrode 47 is formed by electrically connecting the top chassis 41 for fixing the top substrate 37 on which the release button 4 is mounted to the counter electrode 48 of the antenna substrate 39. The area that becomes the ground potential is enlarged. Thereby, the receiving sensitivity of the antenna unit 5A can be stabilized without increasing the area of the antenna substrate 39.

  In the present embodiment, the top chassis 40 connected to the main board 13 on which the power supply circuit 24 serving as a noise generation source is mounted is electrically connected to the ground 45 on the control circuit 44 side. As a result, noise in the camera body 1 is less likely to be conducted to the antenna unit 5A, and a decrease in reception sensitivity of the antenna unit 5A can be suppressed.

(Second Embodiment)
Next, a digital camera which is a second embodiment of the electronic apparatus of the present invention will be described with reference to FIG. In addition, about the part which overlaps with the said 1st Embodiment, the description is abbreviate | omitted and only a different point is demonstrated. Here, the main chassis 46 corresponds to an example of a third metal body of the present invention.

  FIG. 9 is a view showing a mounting portion of the main chassis 46 on the main board 13.

  In the present embodiment, as shown in FIG. 9, the slit 50 is provided in the ground pattern that connects the power supply circuit 24 to the screw on the surface layer of the main board 13 to which the main chassis 46 is connected via the screw. Further, a through hole 49 is formed at a position sandwiching the slit 50 of the main substrate 13.

  Thereby, when high frequency noise generated in the power supply circuit 24 is conducted through the ground pattern on the surface layer of the main board 13, conduction is cut off at the position of the slit 50 and conduction of noise to the main chassis 46 is cut off. As a result, noise reaching the antenna substrate 39 can be suppressed, and a decrease in reception sensitivity of the antenna unit 5A of the GPS antenna module 5 can be suppressed. Other configurations and operational effects are the same as those in the first embodiment.

(Third embodiment)
Next, a digital camera which is a third embodiment of the electronic apparatus of the invention will be described with reference to FIG. In addition, about the part which overlaps with the said 1st Embodiment, the description is abbreviate | omitted and only a different point is demonstrated.

  FIG. 10 is a perspective view showing the structure of the mounting portion of the GPS antenna module 5.

  In the present embodiment, as shown in FIG. 10, an electromagnetic noise suppression sheet 51 is attached to the top chassis 40 and the top substrate 37. The top substrate 37 connects the main substrate 13 and the wiring of the antenna substrate 39.

  The electromagnetic noise suppression sheet 51 is obtained by processing a special magnetic material into a sheet shape, and can suppress noise in a high frequency band from 10 MHz to 5 GHz when pasted on a noise generation source or a noise conduction path. In the portion where the electromagnetic noise suppression sheet 51 is pasted, the electromagnetic noise suppression sheet 51 acts as a resistive impedance to the circuit in which the noise that is the high frequency current is generated, and removes the high frequency current itself.

  As a result, noise generated in the power supply circuit 24 mounted on the main substrate 13 is less likely to be transmitted to the signal lines of the top chassis 40 and the top substrate 37 that are conductive paths to the antenna substrate 39, and the reception sensitivity of the GPS antenna module 5 is reduced. Can be suppressed. Other configurations and operational effects are the same as those in the first embodiment.

  The configuration of the present invention is not limited to those exemplified in the above embodiments, and the material, shape, dimensions, form, number, arrangement location, and the like are appropriately changed without departing from the gist of the present invention. Is possible.

4 Release Button 5 GPS Antenna Module 5A Antenna Part 13 Main Board 39 Antenna Boards 40 and 41 Top Chassis 44 Control Circuit 45 Ground 47 Antenna Electrode 48 Counter Electrode

Claims (7)

An antenna module comprising: an antenna substrate; an antenna portion provided on a front surface side of the antenna substrate; and a control circuit provided on a back surface side of the antenna substrate via a ground and controlling driving of the antenna portion is mounted. ,
The antenna unit is an electronic device in which an antenna electrode is laminated on a counter electrode provided on the surface side of the antenna substrate via a dielectric,
A first metal body electrically connected to the counter electrode;
An electronic apparatus comprising: a second metal body electrically connected to the ground and electrically connected to a power supply circuit mounted on a main board.   The electronic device according to claim 1, wherein the first metal body holds an operation button.   The electronic apparatus according to claim 1, wherein the control circuit includes an amplifier that amplifies the output of the antenna electrode. The second metal body is electrically connected to the main board via a third metal body,
4. The electronic apparatus according to claim 1, wherein the main board is provided with a slit in a ground pattern connected to a portion to which the third metal body is connected from the power supply circuit. 5. .   5. The electronic apparatus according to claim 1, wherein the second metal body is provided with a plurality of bent portions and a throttle portion.   The electronic apparatus according to claim 5, wherein an electromagnetic noise suppression sheet is attached to the second metal body.   The electronic device according to claim 1, wherein the antenna module is a GPS antenna module.

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