JP2016038443A - Display device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device for a vehicle that prevents malfunction of a circuit to perform stable display output.SOLUTION: There is provided a display device for a vehicle including a liquid crystal display panel 10, a backlight part 20 that includes a circuit board 23 having a light-emitting element 21 mounted thereon performing transmitted illumination of the liquid crystal display panel 10, and a housing 30 that accommodates the backlight part 20, where the housing 30 is held by engagement of a middle case 31 and a lower case 32, and the circuit board 23 has a receiving part 23b provided at a position opposite to a gap S between the middle case 31 and the lower case 32.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a vehicle display device, and is suitable, for example, for a vehicle display device including a backlight unit that illuminates a liquid crystal display panel.

  Conventionally, various vehicle display devices have been proposed, and for example, disclosed in Patent Document 1. In this display device, a liquid crystal display panel is transmitted and illuminated by a backlight unit housed in a housing. The backlight unit includes a light emitting element that emits illumination light that illuminates and transmits the liquid crystal display panel, and the light emitting element is mounted on a circuit board.

JP 2011-164502 A

  However, if there is a minute gap in the housing that houses the circuit board, static electricity may invade from the outside through the gap, such as when assembling the vehicle display device, and the circuit elements (electronic components) mounted on the circuit board There is a possibility that the display output may be damaged due to breakage or malfunction, and it is necessary to take countermeasures.

  Therefore, the present invention has been made in view of this problem, and provides a vehicle display device capable of preventing malfunction of a circuit and performing stable display output.

The present invention is a vehicle display device comprising: a liquid crystal display panel; a backlight unit having a circuit board on which a light emitting element that transmits and illuminates the liquid crystal display panel is mounted; and a housing that houses the backlight unit. And
The housing is held by engaging the first case and the second case,
The circuit board is characterized in that a land is provided at a location facing the gap between the first case and the second case.

  Further, the circuit board is characterized in that lands are provided at locations facing each of the plurality of gaps, and an exposed portion is provided between the lands so that the metal surface is exposed and separated.

Also, one of the lands is formed in a conductive pattern that is not electrically connected,
The other is formed in a conductive pattern connected to ground.

  The present invention relates to a display device for a vehicle, and can prevent malfunction of a circuit and perform stable display output.

The front view which shows embodiment of this invention. AA sectional drawing which shows embodiment same as the above. The figure which shows the circuit board 23 of embodiment same as the above.

  Hereinafter, as an embodiment of a display device for a vehicle according to the present invention, an example applied to a vehicle instrument provided on an instrument panel of a vehicle will be described with reference to the drawings. 1 and 2 show a schematic configuration of a vehicle meter A according to an embodiment of the present invention.

  The vehicle display device includes a liquid crystal display panel 10, a backlight unit 20, a housing 30, a metal frame 40, and a circuit board 50. The liquid crystal display panel 10 is formed by sticking polarizing plates on both front and rear surfaces of a liquid crystal cell in which liquid crystal is sealed in a pair of glass substrates on which transparent electrodes are formed. A light diffusing member 15 and a prism sheet 16 are provided on the rear surface side of the liquid crystal display panel 10. The liquid crystal display panel 10 is connected to the circuit board 50 by a flexible wiring member (not shown).

  The backlight unit 20 is a sidelight type backlight, and includes a light emitting element 21, a light guide plate (light guide member) 22, and a circuit board 23, and transmits and illuminates the liquid crystal display panel 10. The light emitting element 21 of the backlight unit 20 is a top view type light emitting diode, and irradiates the light guide plate 22 with illumination light. The light emitting element 21 is mounted on the circuit board 23.

  The light guide plate 22 is made of a translucent resin such as acrylic and has a flat plate shape. The backlight unit 20 includes a plurality of light emitting elements 21 that are linearly provided along the side end surface of the light guide plate 22. The circuit board 23 is accommodated in the housing 30 and is disposed along the side wall portions 31 c and 32 c of the housing 30. The circuit board 23 has a connector 230 connected to the circuit board 50.

  The housing 30 is formed by molding a synthetic resin, and accommodates the liquid crystal display panel 10, the backlight unit 20, and the circuit boards 23 and 50. The housing 30 includes an intermediate case (first case) 31 and a lower case (second case) 32.

  The middle case 31 integrally includes a front surface portion 31 a that supports the liquid crystal display panel 10 and the like, a side wall portion 31 c on which the locking claws 31 b are formed, and a support portion 31 f that supports the light guide plate 22. The lower case 32 has a bottom surface portion 32a and a side wall portion 32c on which an elastic locking piece 32b is formed. The elastic locking pieces 32 a of the lower case 32 are held by the locking claws 31 b of the middle case 31. Further, at the location where the middle case 31 and the lower case 32 abut against each other, a gap S is generated due to thermal deformation and dimensional error during molding. In this case, a gap S necessary for deformation when the housing 30 is assembled is intentionally provided.

  The metal frame 40 has a front surface portion 41 and a flange portion 42. A rectangular opening 41 b through which the screen of the liquid crystal display panel 10 can be visually recognized is formed in the front surface portion 41 of the metal frame 40. The flange portion 42 of the metal frame 40 is held by the middle case 31 by a locking structure (not shown). The flange portion 42 is connected to the ground electrode of the circuit board 50.

  As the circuit boards 23 and 50, a printed wiring board in which a copper foil pattern (conductive pattern) is applied to a glass epoxy resin board can be applied, and they are connected to each other by connectors 230 and 51. The mounting surface of the circuit board 50 is provided so as to be substantially parallel to the plate surfaces of the liquid crystal display panel 10 and the light guide 22 and to be perpendicular to the mounting surface of the circuit board 23. A microcomputer 55 that controls the liquid crystal display panel 10 and the light emitting element 21 is mounted on the circuit board 50.

  As shown in FIG. 3, the circuit board 23 is provided with receiving portions (lands) 23 a and 23 b made of a copper foil pattern at locations facing the gap S position between the middle case 31 and the lower case 32. The receiving portions 23a and 23b are exposed portions of the copper foil pattern on which no insulating film is formed. In this case, two portions are formed corresponding to the two gaps S. FIG. 3 is a plan view showing opposing surfaces of the side wall portions 31c and 32c of the housing 30 in the circuit board 23, and a cross-sectional view showing the main part thereof.

  One receiving portion 23a is made of a copper foil pattern that is not electrically connected to other electrodes or wirings, and the other receiving portion 23b is mounted on the opposite mounting surface via a conductive through hole 23c. Is connected to ground. Further, in the wiring pattern between the receiving portions 23a and 23b, the exposed portions 23d and 23e of the copper foil formed mutually are provided nearby. Both the exposed portions 23d and 23e are not covered with the insulating film 23f, and are formed at a distance shorter than the distance from the peripheral wiring 231, in this case, within 2 millimeters.

  Depending on the shape of the exposed portions 23d and 23e and the insulating film 23f, if static electricity is applied to one receiving portion 23a through the gap S of the housing 30, the static electricity jumps over the exposed portions 23d and 23e. The electronic components such as the other wiring 231 and the light emitting element 21 formed around the one receiving portion 23a and provided with the insulating film 23f are guided to the ground electrode connected to the other receiving portion 23b. It is possible to prevent static electricity from being transmitted. In addition, since the receiving portions 23a and 23b are not conductive, the ground wiring can be shortened, and even in the case of the elongated circuit board 23 for the backlight portion 20 having the light emitting elements 21 in a row, an antenna structure that transmits noise. It is hard to become.

  Such a vehicle display device includes a liquid crystal display panel 10, a backlight unit 20 having a circuit board 23 on which a light emitting element 21 that transmits and transmits the liquid crystal display panel 10 is mounted, a housing 30 that houses the backlight unit 20, and The housing 30 is held by engaging the middle case 31 and the lower case 32, and the circuit board 23 has a gap S between the middle case 31 and the lower case 32. The receiving part 23b is provided in the location which opposes.

  Therefore, even if static electricity enters through the gap S, it can be received at a specific location, so that it is possible to prevent static electricity from being applied to other electronic components and cause malfunction of the circuit. Thus, the vehicle display device can perform the display output.

  Further, the circuit board 23 is provided with receiving portions 23a and 23b at locations facing the respective gaps S, and exposed portions 23d and 23e in which the copper foil is exposed and separated between the receiving portions 23a and 23b. By providing the cable, each wiring can be shortened to prevent antenna formation while maintaining the structure that leads to static electricity, so that malfunction of the circuit due to static electricity and noise can be prevented and stable display output can be performed. It becomes a device. In particular, even when the mounting surfaces of the circuit boards 5 and 23 are substantially vertical, it is possible to prevent noise from being transmitted and received by forming a wiring that is provided for countermeasures against static electricity and is not used in normal display control as an antenna. it can.

  In addition, one (23a) of the receiving portions is formed in a copper foil pattern that is not electrically connected, and the other (23b) is formed in a copper foil pattern that is ground-connected, so that the ground wiring is longer than necessary. The above-described effects can be obtained.

  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 design changes can be made without departing from the scope.

  The present invention relates to a vehicle display device that is mounted on a moving body and displays various types of information, and is suitable, for example, as an instrument mounted on a moving body that includes an automobile, a motorcycle, an agricultural machine, or a construction machine.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display panel 15 Light diffusing member 16 Prism sheet 20 Backlight part 21 Light emitting element 22 Light guide plate 23 Circuit board 230 Connector 231 Wiring 23a Receiving part (land)
23b Receiving part (land)
23c Through hole 23d Exposed portion 23e Exposed portion 23f Insulating film 30 Housing 31 Middle case (first case)
31a Front part 31b Locking claw 31c Side wall part 32 Lower case (second case)
32a Bottom part 32b Elastic locking piece 32c Side wall part 41b Opening 42 Flange part 50 Circuit board 51 Connector 55 Microcomputer

Claims (3)

A vehicle display device comprising: a liquid crystal display panel; a backlight unit including a circuit board on which a light emitting element that transmits and illuminates the liquid crystal display panel is mounted; and a housing that houses the backlight unit.
The housing is held by engaging the first case and the second case,
The vehicle display device, wherein the circuit board is provided with a land at a position facing a gap between the first case and the second case.   2. The circuit board according to claim 1, wherein lands are provided at locations facing each of the plurality of gaps, and an exposed portion is provided between the lands so that the metal surface is exposed and separated. Vehicle display device. One of the lands is formed in a conductive pattern that is not electrically connected,
The vehicle display device according to claim 2, wherein the other is formed in a conductive pattern connected to ground.

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