JP2016205979A - Instrument device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an instrument device capable of preventing a malfunction due to static electricity in a simple structure even when an earth body cannot be arranged near a display element due to design constraints and the like.SOLUTION: An instrument device comprises: a display board 20 including an opening 21; a display element 11 arranged so as to be visually recognized through the opening 21; a circuit board 30 arranged behind the display element 11 and electrically connected to the display element 11; a holding body 42 for holding the display element 11 and the circuit board 30; a conductive printing layer 50 provided on a rear surface of the display board 20 along the opening 21; and a connecting member 60 in which the conductive printing layer 50 and a reference voltage terminal 31 provided on the circuit board 30 are electrically connected.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an instrument device having a structure for preventing malfunction due to static electricity.

  Conventionally, various instrument devices having a structure for preventing malfunction due to static electricity have been proposed, and for example, disclosed in Patent Document 1. Such an instrument device reduces the potential difference between the display board and the circuit board by electrically connecting the grounding body provided on the rear surface of the display board and the ground terminal provided on the front surface of the circuit board, thereby causing erroneous display due to static electricity. It makes things difficult.

JP 2010-127800 A (FIG. 2)

  However, the instrument device described in Patent Document 1 has room for improvement, for example, when the space for placing the grounding body in the vicinity of the display element is small, the grounding body needs to be processed into a special shape.

  The present invention provides an instrument device that can prevent malfunction due to static electricity with a simple structure even when a grounding body cannot be disposed in the vicinity of a display element due to design restrictions or the like.

  The present invention includes a display board 20 having an opening 21, a display element 11 that is disposed so as to be visible through the opening 21, and a circuit board 30 that is disposed behind the display element 11 and electrically connected to the display element 11. A holding body 42 that holds the display element 11 and the circuit board 30, a conductive printed layer 50 provided on the rear surface of the display board 20 along the opening 21, and the conductive printed layer 50 and the circuit board 30. A connecting member 60 that is electrically connected to the provided reference voltage terminal 31 is provided.

  In addition, the present invention includes a light source 32 mounted on the circuit board 30 so as to face the display board 20, and the display board 20 is provided with a light transmitting part 22 that is transmitted and illuminated by the light source 32 and illumination from the light source 32. The light shielding portion 23 is formed, and the conductive print layer 50 is provided in the region of the light shielding portion 23.

  Further, according to the present invention, the connection member 60 includes a first contact portion 61 that contacts the conductive print layer 50, a second contact portion 62 that contacts the reference voltage terminal 31, and first and second contact portions. The connection part 63 which connects 61 and 62 is comprised.

  The instrument device of the present invention can prevent malfunction due to static electricity with a simple structure even when a grounding body cannot be disposed in the vicinity of the display element due to design restrictions or the like.

The main front view of the instrument apparatus which shows one Embodiment of this invention AA sectional view showing the embodiment Modification of conductive printed layer

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  The instrument device 1 mainly includes a display module 10, a display board 20, a circuit board 30, a case 40 (transparent upper case 41, middle case (holding body) 42, lower case 43), and a switch knob S. It is configured and used as an instrument device for automobiles, motorcycles and the like.

  The display module 10 includes a liquid crystal panel (display element) 11 having polarizing plates attached to 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, and a rear surface of the liquid crystal panel 11 (on the side of the circuit board 30). The backlight unit is provided on the surface of the liquid crystal panel 11 for illuminating the liquid crystal panel 11 and a cell case for storing the liquid crystal panel 11 and the backlight unit. The backlight unit includes a light emitting element (not shown) made of a light emitting diode, and a diffusion plate and a reflector (not shown) for uniformly illuminating the entire liquid crystal panel 11 with illumination light emitted from the light emitting element. The display module 10 and the circuit board 30 are electrically connected by a flexible wiring member such as an FPC (Flexible Printed Circuit) (not shown). An external connector (not shown) is mounted on the circuit board 30, and the instrument device 1 is electrically connected to the vehicle through the external connector. The circuit board 30 is provided with a light emitting element (light source) 32. The light emitting element 32 is made of a light emitting diode, and emits illumination light that shines the display panel 20 and the pointer P.

The display board 20 has a printed layer formed on both front and rear surfaces of a light-transmitting substrate made of a resin such as polycarbonate (PC), and has an opening 21 at a position corresponding to the display module 10 and a position corresponding to the switch knob S. Is provided with a through hole. On the front surface of the display board 20, there is provided an indicator portion made of scales and numbers (not shown). The display board 20 includes a light transmitting part 22 and a light shielding part 23. The translucent part 22 may be printed with translucent ink, and is transmitted and illuminated by the light emitting element 32 provided on the circuit board 30. The light shielding portion 23 has a three-layer structure of black ink. A conductive print layer 50 is provided on the rear surface (surface on the circuit board 30 side) of the display board 20 corresponding to the area of the light shielding portion 23 so as to surround the opening 21. The conductive printed layer 50 is formed of a conductive ink containing a conductive substance such as aluminum flakes, and extends as a conductive path 51 to a point where the conductive printed layer 50 is in contact with the ground body (metallic connecting member) 60.
In the present embodiment, the conductive printed layer 50 surrounds the opening 21 seamlessly, but it does not have to be cut off from the conduction path 51. For example, as shown in FIGS. The printed layers 150 and 250 may be formed along the opening 210 and may be partially cut off. Also, as shown in FIG. The conductive printed layer 350 can also be provided at an easy place (between the switch S and the opening 210), and static electricity can be efficiently conducted to the conduction paths 151, 251 and 351.

  The circuit board 30 is composed of a hard circuit board in which a wiring pattern as a wiring portion is provided on a glass epoxy base material, for example, and various circuit components such as a display module interface, a pointer driving unit, and a pointer driving circuit are electrically connected to the wiring unit. Yes. A grounding portion made of a ground pattern is provided on the front surface of the circuit board 30, and an earth terminal (reference voltage terminal) 31 is provided in the grounding portion. The circuit board 30 is electrically connected to the conductive printed layer 50 provided on the display panel 20 via the ground terminal 31 and the ground body 60. In addition, a light emitting element 32 that emits illumination light that shines the display board 20 and the pointer, and a switch that is operated by a switch knob S are provided.

  The ground body 60 is a conductive member made of a metallic material, and includes a first contact portion 61, a second contact portion 62, and a connecting portion 63 that connects the first and second contact portions 61, 62. It is disposed between the display panel 20 and the ground terminal 31. The first contact portion 61 contacts a conduction path 51 provided on the display panel 20. By providing the conduction path 51, the grounding body 60 can be provided at a position away from the display module 10, so that the degree of freedom in design increases and a simple grounding structure is sufficient. Further, since the ground connection can be made at a position away from the display module 10, the influence on the display malfunction can be reduced. The second contact portion 62 is in contact with the ground terminal 31 provided on the circuit board 30. The connecting portion 63 is bent from the end portion of the first contact portion 61 and extends to the circuit board 30 side, and is bent in front of the ground terminal 31 to become the end portion of the second contact portion 62.

  The ground terminal 31 is formed of, for example, a Z-shaped metal on-board contact, and is entirely Z-shaped. Therefore, the ground terminal 31 has elasticity to expand and contract vertically and is fixed on the circuit board 30 by soldering. Yes. By using the ground terminal 31 having elasticity, reliable contact can be achieved even if a slight shift occurs in the contact position between the second contact portion 13 and the ground terminal 31 during assembly.

  The case 40 is made of a synthetic resin such as ABS, and includes an upper case 41, an intermediate case 42, and a lower case 43. The upper case 41 is insert-molded with a protective panel made of a translucent substrate. The upper case 41 includes a through hole at a location corresponding to the switch knob S.

  The middle case 42 is made of, for example, white synthetic resin. A holder for housing and supporting the display module 10 is integrally formed on the front surface, and the circuit board 30 is fixed on the rear surface. A ground body 60 is fixed to the side wall of the middle case 42.

  The lower case 43 has an opening on the front surface and is fixed to the rear surface of the upper case 41. A middle case 42 in which the display module 10 and the circuit board 30 are fixed is stored in a hollow portion generated inside the upper and lower cases 41 and 43, and the upper and lower cases 41 and 43 are screwed together.

  Next, the electrical configuration of the instrument device will be described. The instrument device 1 inputs a signal related to a power source and vehicle information from the in-vehicle LAN via a vehicle interface circuit on the circuit board 30 and also via a switch interface circuit on the circuit board 30 operated by the switch knob S. Switch information or the like is input, and processing is performed by the control element based on these signals and the switch information. The control element drives the screen and illumination of the display module 10 by a display module interface circuit. The control element drives the light emitting element 32 by an illumination driving circuit.

  With such a configuration, the conductive printed layer 50 and the circuit board 30 disposed along the rear surface of the opening 21 can be electrically connected by the conduction path 51, the ground body 60, and the ground terminal 31.

  Therefore, for example, when the switch knob S is operated while sitting in the driver's seat of a car or while riding a motorcycle, the electric power charged to the vehicle user flows from the fingertip and is applied to the display board 20 via the switch knob S. Even if it is applied as static electricity, the potential difference between the display board 20 and the ground terminal 31 of the circuit board 30 can be reduced, and the influence on the electronic components such as the display module 10 mounted on the circuit board 30 can be prevented. An erroneous display of the module 10 can be prevented. For this reason, it becomes an instrument apparatus which has the malfunction prevention structure by static electricity.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible. For example, the display module 10 is a liquid crystal display element provided with a backlight, but a self-luminous display element such as an organic EL can also be applied. The front surface of the polarizing plate of the display module 10 may be subjected to scratch prevention processing, ultraviolet degradation prevention processing, or the like. Although the conductive printed layer 50 is provided on the rear surface of the display panel 20, it may be provided on the entire light shielding portion 23, and an effect of shielding electromagnetic noise can be expected. Further, the printing surface of the light shielding portion 23 may be provided on the rear surface of the display board 20 (surface on the circuit board 30 side), and conductive ink may be used instead of black ink.

10 Display Module 11 Display Panel (Display Element)
20 Display board 21 Opening part 22 Translucent part 23 Light-shielding part 30 Circuit board 31 Ground terminal (reference voltage terminal)
32 Light emitting element (light source)
40 case 41 upper case 42 middle case (holding body)
43 Lower case 50 Conductive printing layer 51 Conductive path 60 Grounding body (metal connection member)
61 1st contact part 62 2nd contact part 63 Connection part 150,250,350 Conductive printing layer 151,251,351 Conductive path 210 Opening part P Pointer S Switch knob

Claims (3)

A display panel having an opening;
A display element disposed so as to be visible through the opening;
A circuit board disposed behind the display element and electrically connected to the display element;
A holding body for holding the display element and the circuit board;
On the rear surface of the display board, a conductive printed layer provided along the opening,
An instrument device comprising a connection member for electrically connecting the conductive printed layer and a reference voltage terminal provided on the circuit board. A light source mounted on the circuit board opposite to the display board;
The display plate is formed with a light transmitting portion that is transmitted and illuminated by the light source and a light shielding portion that blocks the illumination from the light source,
The instrument device according to claim 1, wherein the conductive printing layer is provided in a region of the light shielding portion. The connection member includes a first contact portion that contacts the conductive printed layer, a second contact portion that contacts the reference voltage terminal, and a connecting portion that connects the first and second contact portions. The instrument device according to claim 1 or 2, characterized in that

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