JP2014034359A - Display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display panel for displaying vehicle information, and obtain sufficient antenna gain in regard to a display device for a vehicle including a radio communication circuit.SOLUTION: A display device for a vehicle includes: a display panel 21 which displays vehicle information by an image; a control means 6 which drives the display panel 21; a radio communication circuit 7 which transmits or receives a predetermined radio signal upon receiving a control signal from the control means 6; and a conductive metal frame 22 which holds the display panel 21. The metal frame 22 is connected to the radio communication circuit 7, and is used also as an antenna for radiating the radio signal in a space.

Description

  The present invention relates to a vehicle display device that is mounted on a vehicle and includes a display panel for displaying vehicle information and includes a wireless communication function.

  Conventional automobiles have come to be equipped with radio receivers in addition to car audio radios, and typical ones are used for security systems such as keyless entry functions and immobilizer functions. . The security system is a system for controlling the opening / closing of the vehicle door and the start switch, and includes a vehicle-side receiver and a transmitter carried by the driver. By the driver's operation, the transmitter transmits a transmission signal that uses the identification code and operation command code assigned to each transmitter as a modulation signal, and when the receiver receives the transmission signal, it demodulates it and receives the identification code. Is determined to be from the transmitter paired with itself, and if a positive determination is made, a control signal corresponding to the operation command code is output to the control ECU of each part of the vehicle to open / close the door, start the engine, etc. .

  Patent Document 1 below proposes a radio wave receiver in which a receiving circuit board on which a receiving circuit is formed is housed in a housing, added to a meter device that displays traveling information such as vehicle speed to the driver. ing.

  Patent Document 2 listed below discloses a radio circuit receiver including a receiving circuit board built in a meter device. In this meter device, a meter circuit board on which a meter circuit for controlling display contents on the display unit to follow the actual running state of the vehicle is stored in the meter housing, and the receiving circuit board of the radio wave receiver is the meter circuit board. It is attached so as to be laminated.

JP-A-9-207717 Japanese Patent Laid-Open No. 8-276864

  However, the radio wave receiver is susceptible to the reception performance such as the antenna gain depending on the installation location. Even if the radio wave receiver is simply integrated with the vehicle display device, the reception performance may be sacrificed, and for example, the stable operation of the keyless entry system may be impaired.

  In addition, in the technique according to the above-mentioned document, it is necessary to separately provide a circuit board in which the wireless communication unit (wireless communication means) is integrated in addition to the main circuit board of the meter device. There is a concern that it is difficult to issue. In particular, with the increase in the number of parts, there has been room for improvement, such as requiring electrical connection and assembly work for fixing them.

  By the way, in recent vehicle display devices, a display device equipped with a TFT (Thin Film Transistor) type liquid crystal display is increasing. Usually, the TFT type liquid crystal display is fixed to a conductive metal frame (metal frame) provided so as to cover the periphery of the display unit, and has a structure in which the metal frame is fixedly supported on a circuit board.

  An object of the present invention is to provide a vehicle display device that can realize a sufficient antenna gain, with respect to wireless communication means built in a vehicle display device that displays vehicle information. .

  A vehicle display device according to the present invention receives a control signal from a display panel that displays vehicle information as an image, a control unit that drives the display panel, and a control signal from the control unit, and transmits or receives a predetermined radio signal. In the vehicular display device including the wireless communication unit that performs and the conductive holding member that holds the display panel, the holding member is connected to the wireless communication unit and radiates the wireless signal to space. It is also used as an antenna.

  The holding member covers a non-display area on the display surface of the display panel, and is electrically connected to the wireless communication means mounted on a circuit board provided on the back side of the display panel. Features.

  The control means controls switching between display / non-display of the display panel, and does not operate the wireless communication means when the display panel is displaying, and the wireless communication means is not displayed, The communication means is operated.

  The present invention relates to a vehicle display device that is mounted on a vehicle and includes a display panel for displaying vehicle information and includes wireless communication means, and can realize a sufficient antenna gain.

The figure which shows the example of a display of the display apparatus for vehicles in embodiment of this invention. The figure which shows the cross section of the display apparatus for vehicles in embodiment same as the above. The figure which shows the electrical structure of the display apparatus for vehicles in embodiment same as the above.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the following description shows one Example which applied this invention to the vehicle-mounted meter.

  FIG. 1 is a diagram illustrating a display example of an on-vehicle meter. In this case, the on-vehicle meter is a composite instrument including a pointer display unit 1, an image display unit 2, and various indicators 3. As shown in a cross-sectional view of FIG. A control means 6, a wireless communication circuit (wireless communication means) 7, a backlight 8, an external connection connector 9 and the like are mounted on the circuit board 5.

  The pointer display unit 1 is printed with a pointer 12 that rotates using a movement (motor) 11 mounted on the circuit board 2 as a drive source, and an indicator unit 13 that includes numerical values and scales to be indicated by the pointer 12. It consists of a display board 14. The pointer display unit 1 is provided so that the indicator unit 13 and the pointer 12 can be illuminated by the backlight 8. In this case, the pointer display unit 1 operates the movement 11 in accordance with the vehicle speed information input via the external communication connector 9 and the arithmetic processing or drive command by the control means 6, and the indicated position of the indicator unit 13 by the pointer 12. Thus, the traveling speed value of the vehicle can be displayed.

  The image display unit 2 is provided with a display panel 21 that displays vehicle information such as desired measurement values and warnings as images by drive control by the control means 6. In this case, vehicle information such as the accumulated travel distance and fuel consumption is displayed on the display panel 21. The display panel 21 is configured to be able to switch screens, and can display and output time and temperature information, input information display by wireless communication, wireless communication status, and the like in addition to vehicle information.

  The display panel 21 is connected to the control means 6 of the circuit board 5 through a flexible wiring (not shown). The flexible wiring plays a role as a signal transmission line for transmitting an image signal to the display panel 21. When the signal speed output from the control means 6 is high, signal reflection or transmission loss due to characteristic impedance mismatch of the transmission line cannot be ignored. In some cases, an impedance controlled impedance of 100Ω may be used.

  The display panel 21 is held between the display board 14 and the circuit board 5 by using a conductive metal frame (holding member) 22, and a display area is formed from the notch opening of the display board 14. It is provided so that it can face. The metal frame 22 has a frame shape that suppresses and surrounds the end of the display panel 21 outside the display area of the display panel 21, and is sandwiched between the circuit board 5 or the spacer 23 made of synthetic resin, The display panel 21 is held from the display panel 14 side. The metal frame 22 is provided so as to be interposed between the display panel 14 and the display panel 21, and is connected to the ground so that static electricity from the display panel 14 side can be transmitted to the ground terminal of the circuit board 5. Has been. In this case, the metal frame 22 is connected to the wireless communication circuit 7 such as a matching circuit mounted on the circuit board 5 through at least two connection portions 24 so that it can act as a part of the antenna. . The connecting portion 24 is formed continuously from the frame-shaped portion of the metal frame 22 and is provided with a portion perpendicular to the display board 14 surface or the circuit board 5 surface. Easily transmit and receive radio waves (radio signals).

  The indicator 3 includes indications of the direction indicator and state, the high beam of the headlamp, the gear position of the transmission, and various warning lights, and lighting of the transmissive design printed on the display board 14 by transmissive illumination by a light source (not shown). The state of the vehicle is displayed and output by flashing. The light source of the indicator 3 is driven by control by the control means 6.

  The housing 4 holds and accommodates the display panel 21, the circuit board 5, the display board 14, and the like, and is a translucent composite that can display the pointer display unit 1, the image display unit 2, and the indicator 3. A front side case 41 made of a resin and a back side case 42 made of a light-shielding synthetic resin that holds each component and covers the circuit board 5 and the like are provided.

  The circuit board 5 is a hard wiring board on which a copper foil pattern is printed and formed as a meter printed board, and is mounted with electronic components such as the movement 11, the backlight 8, the display panel 21, and the control means 6 described above. . In this case, the circuit board 5 is provided in parallel with a predetermined distance from the display board 14 and fixed to the back case 42 with screws. Further, the circuit board 5 is formed with lands for conductive connection to the connection portion 24 of the metal frame 22.

  The control means 6 drives and controls the movement 11, the display panel 21, and the light sources for various indicators 3 described above based on the vehicle information input via the external connection connector 9 and the wiring of the circuit board 5. A microcomputer in which a predetermined program is stored in a storage unit can be applied.

  The storage unit can also be applied to a non-volatile memory such as an EEPROM that stores information transmitted by wireless communication and information necessary for decoding / verifying received signals, and is connected to the control means 6 via a separate wiring. ing. Furthermore, a power supply circuit comprising a constant voltage circuit (not shown) for supplying power to electronic components such as the control means 6 and the wireless communication circuit 7 mounted on the circuit board 5 is provided and input via the external connection connector 9. Electric power is supplied to the on-vehicle meter with voltage adjustment.

  The wireless communication circuit 7 includes, as an antenna function for transmitting and receiving wireless signals, a matching circuit 71 mounted on the circuit board 5, a metal frame 22 having a plurality of connection portions 24 with respect to the circuit board 5, and wiring of the circuit board 5. Are connected in a loop. Therefore, since an antenna portion perpendicular to the substrate surface can be provided, a three-dimensional configuration with a high antenna gain can be easily obtained.

  In addition, in the connection part of the metal frame 22 not used as an antenna function, in addition to being connected directly to a ground plane (not shown) of the circuit board 5, it is connected to a ground plane (not shown) of the circuit board 5 via a circuit means. The frame 22 can be used as a low impedance application. Therefore, since the impedance between the ground of various electronic components mounted on the circuit board 5 and the ground of the circuit board 5 can be reduced, common mode noise generated from the display panel 21 can be suppressed. Therefore, it can contribute to suppression of unnecessary radiation generated from the vehicle display device. In addition, in the connection location of the metal frame 22, various structures can be considered based on the relationship between antenna impedance and static electricity, such as insulation from a ground plane (not shown) of the circuit board 5.

  The backlight 8 can be applied with a light emitting diode for transmissive illumination of the pointer 12, the indicator portion 13 of the display panel 14, and the display panel 21, and is driven and controlled by control by the control means 6. Note that the control means 6 can dim the backlight 8 using PWM, and can illuminate with the optimum luminance.

  The external connection connector 9 is a connection member that connects to a harness 91 that connects the control means 6 and the electronic unit on the vehicle body side through a hole in the back side case 42 of the housing 4. Via the external connection connector 9 and the harness 91, the on-vehicle meter is connected to the power source and the vehicle information is received (wired communication).

  According to the above vehicle-mounted meter, the circuit board 5 on which the control means 6 for controlling display of vehicle information is mounted and the metal frame 22 that can act as an antenna as well as a holding member for the display panel 21 are provided apart from each other. be able to.

  Therefore, by providing the antenna wiring other than the circuit board 5 surface, the influence of electromagnetic shielding due to the wiring pattern on the circuit board 5 surface can be reduced, the antenna gain can be improved, and the fixing means and the conductive means can be combined. Because of this, it is possible to suppress the increase in parts, and since the electrical connection, the structure for fixing them, and the assembly work become easy, it has a wireless communication function that can realize sufficient antenna gain with a simple configuration It becomes a display device for vehicles.

  Further, the method of making the circuit board 5 and the metal frame 22 conductive to form an antenna has been described as an example, but the present invention is not limited to this. For example, a flexible wiring is provided between the circuit board 5 and the metal frame 22. It may be routed.

  In addition, when the on-vehicle meter does not require a wireless communication function, it is only necessary to configure without mounting the wireless communication circuit 7 and the matching circuit 71, and a highly versatile vehicle display device corresponding to the difference in the equipment of the vehicle, Become.

  In addition, the conductor pattern on the circuit board 5 and the conductive means for fixing and supporting the circuit board 5 are used as a loop antenna element or a monopole antenna element, and the antenna can be used while suppressing costs while utilizing existing electronic components. Can be configured. Note that, in any of the loop antenna element and the monopole antenna element described above, the size of the metal frame 22 varies depending on the screen size of the display panel 21. In this case, since the impedance changes according to the metal frame 22, the circuit constant of the matching circuit 71 can be changed.

  FIG. 3 shows a block diagram in the embodiment of the present invention, in which the metal frame 22 and the circuit board 5 are electrically connected via a ground line (hereinafter referred to as GND line) G3 to form a loop antenna element. Represents.

  The control means 6 sends an image information display signal and a wireless communication signal (control signal) to the display panel 21 and the wireless communication circuit 7, respectively. As the display panel 21, for example, a TFT liquid crystal display panel can be applied, and vehicle information that changes from moment to moment can be displayed as an image to the driver. The image information display signal is transmitted to the display panel 21 via the wiring pattern of the circuit board 5 and the conductive wire L3 formed of flexible wiring. The wireless communication signal is transmitted to the wireless communication circuit 7 via the lead L1.

  In the wireless communication circuit 7, the wireless communication signal is converted into a high-frequency signal (wireless signal) and sent to the metal frame 22 having an antenna function. In addition, since the said high frequency signal flows to the conducting wire L2, it is necessary to use the transmission line by which impedance matching was carried out as needed. It is also conceivable to insert a matching circuit (not shown) in the middle of the conducting wire L2. The high-frequency signal transmitted to the metal frame 22 side having the antenna function can radiate the high-frequency signal to the space by using the electrically closed circuit of the conducting wire L2, the metal frame 22, the GND line G3, and the GND line G2 as a loop antenna. Become.

  Further, for example, when used for wireless communication for authentication at the time of unlocking operation, the control means 6 can be set as a condition for performing wireless communication with respect to the power saving mode in the vehicle stop state or the stop state of the display panel, When the vehicle is in operation, wireless communication can be performed only when the vehicle is stopped without performing wireless communication. At this time, since the vehicle display device is also in a communication state under the power saving mode, electronic components such as the display panel 21 and the backlight 8 are stopped (turned off), that is, noise around the metal frame 22 having an antenna function. It is possible to improve the reliability of communication with less influence.

  Further, the control means 6 controls to switch between display / non-display of the display panel 21 regardless of the stop of the vehicle, and when the display panel 21 is displaying, the wireless communication circuit 7 is not operated and the display panel 21 is not operated. However, the wireless communication circuit 7 may be set to operate when not displayed, and the same effect as described above can be obtained. For example, the display panel 21 and the backlight 8 that illuminates the display panel 21 can be controlled so as to perform communication after being temporarily stopped (for example, for 0.5 seconds).

  The vehicle display device of the present invention has been described by way of example in the configuration of the embodiment described above, but the present invention is not limited to this, and the gist of the present invention is also achieved in other configurations. It goes without saying that various improvements and display changes can be made without departing from the scope. For example, in addition to a general screw as a fixing member, a locking structure such as a metal hook may be used, or a locking portion and a screw fixing portion may be used in combination. Similar effects can be obtained.

  Moreover, it can also be set as a monopole antenna element by setting it as the structure which does not electrically connect the metal frame 22 and the circuit board 5 via a GND line. In addition, by defining an electrical connection method between the conductive means, it is possible to configure a vehicle display device in consideration of suppression of unnecessary radiation while performing use as an antenna.

  The present invention relates to a vehicle display device that is mounted on a vehicle and displays various types of vehicle information, and performs wireless communication, such as a security system mounted on a mobile body including an automobile, a motorcycle, or an agricultural machine or a construction machine. It can be applied as a vehicle display device.

DESCRIPTION OF SYMBOLS 1 Pointer display part 11 Movement 12 Pointer 13 Indicator part 14 Display board 2 Image display part 21 Display panel 22 Metal frame (holding member)
23 Spacer 3 Indicator 4 Housing 41 Front side case 42 Back side case 5 Circuit board 6 Control means 7 Wireless communication circuit (wireless communication means)
71 Matching circuit 8 Backlight 9 External connection connector 91 Harness

Claims (3)

A display panel for displaying vehicle information as an image;
Control means for driving the display panel;
A wireless communication means for receiving or transmitting a predetermined wireless signal in response to a control signal from the control means;
In a vehicle display device comprising a conductive holding member that holds the display panel,
The display device for vehicles, wherein the holding member is connected to the wireless communication means and serves also as an antenna for radiating the wireless signal to space.   The holding member covers a non-display area on the display surface of the display panel, and is electrically connected to the wireless communication means mounted on a circuit board provided on the back side of the display panel. The vehicle display device according to claim 1. The control means controls switching between display / non-display of the display panel and does not operate the wireless communication means when the display panel is displaying,
The vehicle display device according to claim 1, wherein the wireless communication unit is operated when the display panel is not displayed.

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