JPH043744B2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a resin molded product consisting of a light-transmitting part and a light-shielding part, such as an automobile instrument panel or various meter panels, and more specifically, a resin molded product that is made entirely conductive. It is related to goods.

Prior Art Resin molded products such as automobile instrument panels and various meter panels are made of transparent or semi-transparent material not only for light-shielding parts, but also for viewing meters inside the molded product and for recognizing the light of lighting indicators. It has a light part, and is formed by fitting the light-transmitting part into the light-shielding part or by two-color molding.

Incidentally, modern automobiles are rapidly becoming electronic, with microcontrollers controlling various parts such as the engine combustion system, air conditioning, suspension, speedometer, and warning devices. Other electronic components are installed at various locations. Electric circuits made up of these electronic components may malfunction when exposed to electromagnetic waves from the outside, or may emit electromagnetic waves themselves, causing other devices to malfunction.

Therefore, if the electric circuit is installed inside the instrument panel, etc., which is not conductive, most of the electromagnetic waves will pass through the instrument panel, making it vulnerable to the electromagnetic waves, which may cause the malfunction. There was a risk that this would lead to Even if a conductive paint is applied to the instrument panel, it cannot be applied to the light-transmitting parts because it impairs its light-transmitting properties, and a sufficient shielding effect cannot be obtained.

Furthermore, various general-purpose computers, word processors, and the like sometimes use synthetic resin cases that have a light-transmitting part and a light-blocking part, but the same problems as described above occur in this case as well.

Conventionally, electronic circuits have been shielded with metal boxes to prevent malfunctions such as those described above, but this has resulted in problems such as increased cost, increased size of electronic devices, poor assembly performance, and increased product weight.

Purpose This invention was made in order to solve the conventional problems as described above, and the purpose is to make the entire transparent part conductive and sufficiently block electromagnetic waves without impairing the transparency of the transparent part. The object of the present invention is to provide a new resin molded product that can prevent malfunctions of electric circuits such as microcomputers installed inside or outside.

Structure This invention provides a resin molded product consisting of a light-transmitting part and a light-shielding part, in which a transparent conductive film made of a metal oxide is formed on at least one side of the light-transmitting part, and
A paint conductive film made of conductive paint is formed on at least one side of the light-shielding portion, and the transparent conductive film and the paint conductive film are electrically connected.

Embodiment A first embodiment in which the present invention is embodied in an automobile instrument panel will be described below with reference to FIGS. 1 to 3.

1 in the drawing indicates the entire instrument panel of the automobile. 2
A plurality of transparent parts are provided in the instrument panel 1 and are made of a transparent methacrylic resin (PMMA) plate. Each transparent part 2
A speedometer 3, a bar graph tachometer 4, a fuel gauge 5, a water temperature gauge 6, etc., which are mounted inside the instrument panel 1 and are comprised of LEDs, etc., are provided so that they can be viewed from the front. 7 is a plurality of translucent parts having translucent properties, which are made of a milky-white translucent PMMA resin plate, and are used for hydraulic,
It is provided so as to transmit light from a lighting indicator (not shown) for recognizing a door ajar, a remote switch of a headlight, a handbrake, etc.

Reference numeral 8 denotes a transparent conductive film formed by sputtering on the back surface of each of the transparent and translucent light-transmitting parts 2 and 7, and the film thickness is approximately 1000 Å (angstrom).
It is made of ITO (indium tin oxide) film and has a surface resistance of approximately 5×10 ^-4 Ωcm. Since this transparent conductive film 8 has high transparency,
The translucency of each translucent portion 2, 7 is not impaired.
The method and conditions for forming the transparent conductive film 8 will be described in detail later.

9 is a light shielding part molded in two colors around all the transparent parts 2 and 7, and is a black part.
It is made of an ABS resin plate, and its back surface is almost flush with the back surfaces of the transparent parts 2 and 7. The light shielding portion 9 blocks light and makes the interior components such as the speedometer 3 stand out. The two-color molding method will be described later.

10 is about 2 mm over the entire back surface of the light-shielding part 9 and the transparent conductive film 8 of all the light-transmitting parts 2 and 7.
It is a paint conductive film coated on the edge 8a of the width so as to be electrically conductive with each other, and an acrylic conductive paint containing nickel powder is used, and the resistance is approximately 1Ωcm.
It has a surface resistance of

Due to the transparent conductive film 8 and the paint conductive film 10, the entire back surface of the instrument panel 1 has continuous conductivity.

Regarding the first embodiment configured as described above, the manufacturing method thereof will be explained next.

First, the sputtering apparatus will be explained according to FIG. 2. Reference numeral 11 indicates a vertical sputtering apparatus. Reference numeral 12 denotes a flat target, at least the surface of which is made of ITO. 13
is a high frequency power source; 15, 16, and 17 are a vacuum pump, an argon gas cylinder, and a leak valve, each connected to a sputtering device; a flow meter 18 is connected to the argon gas cylinder 16.

A transparent conductive film 8 is provided on the transparent parts 2 and 7 of the instrument panel 1.
In order to form a
Reduce the pressure to about 10 ^-5 Torr.

Next, open the cylinder 16 and check the inside of the device 11 by 8.0×.
Maintained in an argon gas atmosphere of about 10 ^-4 Torr,
Apply 1KW of 13.6MHz high frequency. Then, the argon gas is dissociated into plasma, and the target 1
The argon ions accelerated in two directions strike out the ITO on the surface of the target 12. ITO scatters and adheres to the back surfaces of the transparent parts 2 and 7, and the transparent conductive film 8
is formed.

Next, the two-color molding will be explained. The transparent parts 2 and 7 on which the transparent conductive film 8 has been formed as described above are set in a predetermined position in the mold of an injection molding machine (not shown), and the black areas around the transparent parts 2 and 7 are
By injection molding ABS resin, the light-shielding portion 9 is integrally formed with the light-transmitting portions 2 and 7.

After molding as described above, the transparent conductive film 8 on the back surface of the transparent parts 2, 7 is masked leaving the edge 8a. Then, the conductive paint was applied to the back surface of the instrument panel 1 to a thickness of 20 μm, and after heating and drying at 70°C for 45 minutes,
When the masking material is removed, a paint conductive film 10 is formed, and this embodiment is completed.

The instrument panel 1 of this first embodiment has electrical conductivity over the entire back surface due to the transparent conductive film 8 and the paint conductive film 10 that are electrically conductive to each other.

According to experiments, data was obtained that a remarkable electromagnetic shielding effect appears when the average surface resistance of the entire instrument panel 1 is 1 to 2 Ωcm or less (of course, even if it is 2 Ωcm or more, a certain electromagnetic shielding effect appears). . In this example, since the surface resistance of the transparent conductive film 8 is extremely low at 5×10 ^-4 Ωcm, the surface resistance of the entire instrument panel 1 is approximately 1 Ωcm, which is almost dominated by the surface resistance of the paint conductive film 10, which is practically Provides sufficient electromagnetic shielding effect.

Therefore, when a microcomputer, etc. that controls a speedometer, warning device, etc. is installed inside the instrument panel 1, the electric circuit consisting of the CPU, memory IC, clock IC, and other electronic components is connected to the outside of the instrument panel 1. Shielded and protected from electromagnetic waves to prevent malfunction.
Further, since the electromagnetic waves generated from the electric circuit are prevented from being radiated outside the instrument panel 1, other external devices (for example, a microcomputer incorporated in the steering wheel pad, etc.) will not malfunction.

Next, a second embodiment of the present invention will be described with reference to FIG. 4. In this embodiment, a transparent conductive film 8 and a paint conductive film 10 are provided on the front surfaces of the light-transmitting parts 2 and 7 and the front surface of the light-shielding part 9, respectively. This embodiment differs from the first embodiment only in the points provided.

Therefore, the second embodiment has the same effects as the first embodiment, and can also serve as a color coating for the light-shielding portion 9 by arbitrarily determining the color type of the conductive paint.

Next, a third embodiment of the present invention will be described with reference to FIG. 5. In this embodiment, the light-transmitting parts 2 and 7 are fitted into the light-shielding part 9 instead of the two-color molding. This embodiment differs from the first embodiment in that a paint conductive film 10 is provided on the front surface of the light-shielding portion 9 and is electrically connected to the transparent conductive film 8 on the back surface of the light-transmitting portions 2 and 7. That is, the light-shielding portion 9 is first formed independently, and a fitting portion 9a is formed to accommodate the light-transmitting portions 2 and 7 in a stepped manner. The paint conductive film 10 is formed on the front surface of the light shielding portion 9 so as to curve up to the insertion portion 9a. The light-transmitting parts 2 and 7 with the transparent conductive film 8 formed on the back surface are fitted into the fitting part 9a and fixed with an adhesive, and the transparent conductive film 8 and the paint conductive film 10 are electrically connected to each other.

Therefore, this third embodiment also has the same effects as the first embodiment and even the second embodiment.

It should be noted that the first and third embodiments have better protection than the second embodiment because the transparent conductive film 8 is on the back side.

Next, a fourth embodiment of the present invention will be described with reference to FIG. It differs from the third embodiment in that it is provided on the back surface.

Therefore, this embodiment also has the same effects as the first embodiment.

It should be noted that the present invention is not limited to the configurations of each of the embodiments described above, and can be embodied as follows, for example.

(1) In addition to the above-mentioned ITO, various metal oxides having conductivity and transparency, such as tin oxide, indium oxide, zinc oxide, titanium oxide, and aluminum oxide, can be used as the material for the transparent conductive film 8.
The thickness of the transparent conductive film 8 is not particularly limited unless the surface resistance is particularly high (for example, 2 Ωcm or more). In the case of ITO, the surface resistance was measured while increasing and decreasing the thickness in the range of about 800 to 1200 Å, and it was found to be constant at about 5×10 ⁻⁴ Ωcm regardless of the film thickness. Further, the transparent conductive film 8 may be formed by a vacuum deposition method, an ion plating method, etc. other than sputtering.

(2) As the conductive paint, acrylic, epoxy, polyester, or other paints containing various conductive powders such as nickel powder, copper powder, silver powder, or carbon black can be used. The thickness of the paint conductive film 10 is not limited as long as the surface resistance does not become particularly high. Surface resistance varies depending on the type and concentration of conductive paint, so
The thickness of the paint conductive film 10 cannot be determined unconditionally. As an example, the paint conductive film 10 of the above embodiment
When the thickness of is reduced to 10 μm, the surface resistance becomes approximately
It became 1.5Ωcm.

(3) Various synthetic resin materials can be used for the light-transmitting parts 2, 7 and the light-shielding part 9, and the method of joining them is not limited.

(4) In addition to the instrument panel 1 of an automobile, the present invention can be embodied in various resin molded products such as cases and panels for televisions and audio equipment with built-in computers, word processors, and microcomputers.

(5) A transparent conductive film 8 may be formed on both sides of the transparent parts 2 and 7. The same applies to the paint conductive film 10.

Effects As detailed above, the present invention provides a resin molded product consisting of a light-transmitting part and a light-shielding part, in which a transparent conductive film made of a metal oxide is formed on at least one side of the light-transmitting part, and at least one of the light-shielding parts. By forming a paint conductive film made of conductive paint on one side and creating electrical continuity between the transparent conductive film and the paint conductive film, the entire surface becomes conductive without impairing the transparency of the transparent part and sufficiently blocks electromagnetic waves. This has the excellent effect of preventing malfunctions of electrical circuits such as microcomputers installed internally or externally.

[Brief explanation of drawings]

FIG. 1 is a front view of the first embodiment embodying the present invention, FIG. 2 is a schematic sectional view showing a part of the manufacturing method (sputtering), FIG. 3 is a sectional view of the main part, Figures 5 and 6 are the second, third and third figures of the present invention, respectively.
FIG. 4 is a sectional view of a main part of a fourth embodiment. DESCRIPTION OF SYMBOLS 1... Instrument panel, 2, 7... Transparent part, 8... Transparent conductive film, 9... Light shielding part, 10... Paint conductive film.

Claims (1)

[Scope of Claims] 1. In a resin molded product 1 consisting of light-transmitting parts 2, 7 and a light-shielding part 9, a transparent conductive film 8 made of a metal oxide is formed on at least one side of the light-transmitting parts 2, 7, and a light-shielding A resin molded article characterized in that a paint conductive film 10 made of a conductive paint is formed on at least one side of the portion 9, and the transparent conductive film 8 and the paint conductive film 10 are electrically connected. 2. The resin molded product according to claim 1, wherein the transparent conductive film 8 is formed by sputtering. 3 A transparent conductive film 8 is formed on one side of the light-transmitting parts 2 and 7, and a light-shielding part 9 is formed in two colors on the same side of the light-transmitting parts 2 and 7, and the same side of the light-shielding part 9 as the transparent conductive film 8 is formed. A resin molded article according to claim 1 or 2, characterized in that a paint conductive film 10 is formed on one side of the resin molded article. 4 A transparent conductive film 8 is formed on one side of the light-transmitting parts 2 and 7, a fitting part 9a is provided in the light-shielding part 9, and a paint conductive film 1 is formed on one side opposite to the transparent conductive film 8.
2. The resin molded article according to claim 1 or 2, characterized in that the transparent portions 2 and 7 are fitted into the fitting portion 9a.