JPH10312705A - Molded lens made of synthetic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a lens made of synthetic resin that is used for a light for the vehicles so that snow may not lie on the surface of the lens, water may not be frozen to the surface of the lens and the lense may not be clouded. SOLUTION: A conductive pattern 9 is printed beforehand with Ag paste on a transparent sheet materials (PC sheet 8 for example). As another example of enforcement, a pair of conductive pattern (12, 13) may be printed with carbon paste resistance membrane 14 printed between them. When a lens 2 made of synthetic resin is molded, a pre-printed transparent sheet (PC sheet 8 for example) is joined to the lens surface by insert molding. The temperature of the lens 2 made of synthetic resin is raised by carrying an electric current in the Ag paste conductive pattern 9 or the carbon paste resistance membrane 14 and generating heat, in order to melt snow or ice or to clear the clouded lens.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin lens for forming a vehicular lamp.

[0002]

2. Description of the Related Art FIG. 4 is a sectional side view for explaining a problem in a vehicular lamp using a synthetic resin lens.
A synthetic resin lens 2 is mounted so as to cover the front opening of the lamp housing 1. A bulb socket 3 is installed in the lamp housing 1 to support a light source bulb 4. Reference numeral 5 denotes a shade for blocking the direct light flux emitted from the light source bulb 4 from entering the lens surface of the synthetic resin lens 2. In the present invention, the lens surface refers to a surface on which a light beam passing through the lens enters or exits. Some lens surfaces have a smooth lens surface, and some have a prism element formed integrally.

[0003]

There are various methods for mounting a vehicle lamp on a vehicle body. In any case, the lens is mounted with the outer surface of the lens exposed to the atmosphere. For this reason, there are many occasions when the outer surface of the lens is exposed to wind and rain or wetted with car wash water. (Refer to FIG. 4) In cold regions, snow 6 may adhere to the outer surface of the lens 2. When the outer surface of the lens is covered with snow in this way, the amount of light passing through the lens is reduced and visibility is reduced, which is dangerous.
In addition to snowfall, if rainwater or car wash water adheres to the outer surface of the lens and freezes, the amount of light passing therethrough is reduced and visibility is reduced. Further, when fine water droplets 7 are deposited on the inner surface of the lens due to a change in the temperature in the lamp room, the passing light flux decreases (so-called the lens becomes cloudy), so that the visibility decreases. In order to solve the above problem and prevent the visibility from being lowered, it is conceivable to heat the lens by attaching a heating wire to the lens surface. However, a lens of a vehicle lamp is generally made of a synthetic resin material, and it is not easy to attach a heating wire to a lens surface of the synthetic resin lens. The present invention has been made in view of the above circumstances, and is a synthetic resin that can prevent snow, icing, and fogging, can be quickly eliminated, and is suitable for mass production at low cost industrially. It is an object of the present invention to provide a molded lens made of the same.

[0004]

The basic principle of the present invention created to achieve the above object will be briefly described with reference to FIG. 1A corresponding to the embodiment. is there. That is, polycarbonate (hereinafter, PC
Ag paste conduction pattern 9 is printed on a sheet 8 made in advance), and when the synthetic resin lens 2 is formed of a synthetic resin material, the printed PC sheet 8 is insert-molded. Let them stick together. Based on the principle described above, the configuration of the synthetic resin molded lens according to the present invention is a substantially transparent electrically insulating sheet on which a conductive pattern is printed in a lens of a vehicle lamp molded of a synthetic resin material. The shape member is fixed to the lens surface by insert molding, and when power is supplied to the conductive pattern, the lens surface is heated. According to the molded lens made of a synthetic resin according to the present invention described above, a conductive pattern to be energized and heated is preliminarily printed on a sheet-shaped member. , Can be created quickly and easily. Then, the sheet-like member on which the conductive pattern is printed is integrally fixed to the lens made of synthetic resin by insert molding to the lens, so that the mounting operation can be easily performed with high precision and at low cost. In particular, when a conductive pattern is provided on the prism surface of the lens, when the conductive pattern is printed on a sheet-like member,
Since the printing is performed by the sheet member alone, a conductive pattern having a correct shape can be formed without being affected by the irregularities of the prism surface, and the sheet member on which the conductive pattern is printed as described above is insert-molded. The lens is integrally fixed to the lens by applying a known insert molding technique, and by arranging the sheet-shaped member on the prism surface of the lens and integrally molding the same, the synthetic resin lens can be formed without particular difficulty. A conductive pattern can be formed on the prism surface. When a current is applied to the conduction pattern configured as described above to generate heat, the lens surface of the synthetic resin molded lens is heated and the temperature rises. When the temperature of the lens is increased by heating, snow and ice adhering to the lens surface are melted, so that the amount of passing light cannot be reduced. Further, even if the inner surface of the lens is clouded, the lens evaporates when heated, and the optical performance of the lens is restored. Furthermore, if the conduction pattern on the lens surface is energized and maintained at an appropriate temperature (40 to 60 ° C.), even if snow falls, it melts immediately, so that it is possible to prevent a decrease in the amount of passing light due to snow accumulation. Further, even when the temperature is 0 ° C. or less when the lens is wet with rainwater or car wash water, there is no possibility that the water will freeze if the lens is kept warm.

[0005]

FIG. 1 shows two embodiments of a synthetic resin molded lens according to the present invention. FIG. 1 is a perspective view cut along a vertical plane perpendicular to the lens surface. It is a figure which added the conduction pattern of the part removed by the virtual line, and (A) is an embodiment using a conduction pattern as a heating element, (B) is an embodiment in which a heating element is provided in addition to the conduction pattern. , Respectively. (Refer to FIG. 1A) Reference numeral 8 denotes a PC sheet, which is integrally molded inside the lens surface by insert molding when the synthetic resin lens 2 is injection-molded with a PC material. When the sheet-like member and the molded lens are made of the same material as in the embodiment of the present example, the compatibility is excellent, and the shape as the sheet-like member does not always remain, and the shape as the sheet is Although they may disappear, they fall within the technical scope of the present invention. The case where the lens material and the sheet material are different will be described later in detail. The PC sheet 8 includes:
Before the insert molding, the conductive pattern 9 is printed in advance with the Ag paste, and remains after the insert molding. When the Ag paste conducting pattern 9 is energized through the terminals 10a and 10b, resistance heating is generated in the Ag conducting pattern 9, and the lens surface of the synthetic resin molded lens 2 is heated to increase the temperature, thereby preventing snow accumulation, icing and clouding. It has a elimination effect and a preventive effect.

(See FIG. 1B.) In the embodiment of the present embodiment, the comb-shaped cathode-side conductive pattern 13 connected to the terminal 11a and the comb-shaped anode-side conductive pattern 12 connected to the terminal 11b face each other. The resistive film 14 is printed with a carbon paste between the conductive patterns of both the positive and negative sides while being printed apart. The terminals 11a,
When current is passed through the resistor 11b, the lens surface of the synthetic resin molded lens 2 is heated mainly by resistance heat of the carbon paste resistance film 14, and the snow, ice and cloudiness disappear as in the embodiment of FIG. An action and a preventive action are achieved. In the embodiment of FIG. 1B, when printing the carbon paste resistance film 14, it is relatively easy to make the current value equal to a desired value by controlling the resistance value to a desired value. Easy. In the present embodiment, the resistance value is set so that the lens temperature can be maintained at 40 to 60 ° C. in consideration of the usage conditions of the vehicular lamp using the molded lens. When a conduction pattern is used as a heating resistor as shown in FIG. 1A, it is desirable to provide a thermostat (not shown) that acts to keep the lens temperature at 40 to 60 ° C.

FIG. 2 shows a PC sheet using the embodiment shown in FIG. 1 described above, and FIG. 2 (A) shows a printed conductive pattern as a heating resistor according to the embodiment shown in FIG. 2 (A). FIG. 2B is a front view schematically illustrating a PD sheet, and FIG. 2B is a front view schematically illustrating a PC sheet on which a conductive pattern with a carbon paste resistive film according to the embodiment of FIG. 2B is printed. It is. The PC sheet of the present embodiment used had a thickness of 0.3 to 1.5 mm. Although the conduction pattern was printed using an Ag paste, the present invention is not limited to the Ag paste when carrying out the present invention.
For a substantially transparent electrically insulating material (not limited to PC), any conductive material that can be used as a printing ink can be used. In the embodiment of FIG. 2A, the Ag paste conductive pattern 9 is printed on one side of the PC sheet 8 so as to be bent substantially uniformly, and this conductive pattern 9 is used as a heating resistor. In the embodiment of FIG. 2 (B), the comb-shaped cathode-side conductive pattern and the comb-shaped anode-side conductive pattern 12 are printed with an Ag paste in such a manner that the comb teeth are opposed to and separated from each other in parallel. Further, a carbon paste resistive film (shown with spots) is printed in the area where the teeth of the comb face in parallel. In this embodiment, the conductive pattern printed with the Ag paste also slightly generates heat, but mainly the carbon paste resistance film 14 functions as a heat generating resistor.

FIG. 3 is a partial sectional view showing three examples of the embodiment of the synthetic resin molded lens according to the present invention.
Shows a state in which a PC sheet is insert-molded on the inner surface of the transparent lens, and FIG.
(C) illustrates a state where the sheet is insert-molded, and (C) illustrates a state where the PC sheet is insert-molded on the outer surface of the transparent lens. The embodiment shown in FIG. 3A corresponds to the embodiment shown in FIG. 1 described above, and a PC sheet 8 is integrally formed on the inner surface side of a transparent lens 15 made of synthetic resin. When the PC sheet 8 is disposed on the inner surface of the lens as described above, the conductive pattern and the resistive film (not shown in FIG. 3) printed on the PC sheet 8 do not come into contact with foreign substances (raindrops, dust, etc.) in the air. It is convenient. It is desirable that the synthetic resin material for forming the lens and the sheet material of the sheet-like member on which the conductive pattern is printed are made of the same material as much as possible because they have compatibility. When using different types of synthetic resin materials, materials having compatibility are selected and used. However, when a material having poor weldability is used for some reason, a heat-sensitive adhesive is preferably used in combination. For example, when the lens material is methacrylic resin (PMMA), strong bonding strength can be obtained by using Sunguard Sheet (trade name) manufactured by Mitsubishi Engineering-Plastics Corporation as the sheet-like member.

In the embodiment shown in FIG. 3B, a PC sheet 8 having a conductive pattern (not shown) printed on the surface of a prism element 16a of a synthetic resin prism lens 16 is shown.
Is provided and insert-molded. When a resistance heating element is provided on a curved surface as in the present embodiment, the practical value of the present invention is very high. In the embodiment of FIG.
The C sheet 8 was disposed on the outer surface of the transparent lens 15 made of synthetic resin. Although not shown, a PC sheet can be provided on the surface of the prism lens 16. When the PC sheet 8 is provided on the outer surface of the lens, the PC
In order to protect the conductive pattern and the resistive film printed on the sheet from foreign substances (dust and the like) in the air, (a) a top coat is applied on the PC sheet 8. (B) The printed surface of the PC sheet 8 is disposed facing the lens. It is desirable to take appropriate measures such as.

[0010]

As described above, according to the embodiment of the present invention, the structure and function thereof are clarified. According to the synthetic resin molded lens according to the present invention, a conductive pattern for generating heat when energized is formed in a sheet. Since printing is performed on the shape member, a high-quality conductive pattern can be quickly and easily created at low cost by applying a known printing technique. Then, the sheet-like member on which the conductive pattern is printed is integrally fixed to the lens made of synthetic resin by insert molding to the lens, so that the mounting operation can be easily performed with high precision and at low cost. In particular, when a conductive pattern is provided on the prism surface of a lens, when the conductive pattern is printed on a sheet-shaped member, the sheet-shaped member is printed alone, so that accurate printing can be performed without being affected by irregularities on the prism surface. A conductive pattern having a shape can be formed, and the sheet-like member on which the conductive pattern is printed as described above is integrally fixed to the lens by insert molding. By arranging the sheet-like member on the prism surface and integrally molding the same, a conductive pattern can be formed on the prism surface of the synthetic resin lens without any particular difficulty. When a current is applied to the conduction pattern configured as described above to generate heat, the lens surface of the synthetic resin molded lens is heated and the temperature rises. When the temperature of the lens is increased by heating, snow and ice adhering to the lens surface are melted, so that the amount of passing light cannot be reduced. Further, even if the inner surface of the lens is clouded, the lens evaporates when heated, and the optical performance of the lens is restored. Furthermore, if the conduction pattern on the lens surface is energized and maintained at an appropriate temperature (40 to 60 ° C.), even if snow falls, it melts immediately, so that it is possible to prevent a decrease in the amount of passing light due to snow accumulation. Also, even if the temperature drops to 0 ° C or less when the lens is wet with rainwater or car wash water,
If the lens is kept warm, there is no risk of water freezing.

[Brief description of the drawings]

FIG. 1 shows two embodiments of a synthetic resin molded lens according to the present invention. FIG. 1 is a perspective view cut by a vertical plane perpendicular to the lens surface, and FIG. It is a figure which added a conduction pattern with a virtual line, (A) is an embodiment using a conduction pattern as a heating element, (B)
Represents an embodiment in which a heating element is provided in addition to the conduction pattern.

FIG. 2 shows a PC used in the embodiment shown in FIG.
FIG. 2A is a front view schematically illustrating a PC sheet on which a conduction pattern as a heating resistor according to the embodiment of FIG. 2A is printed, and FIG. FIG. 2 is a front view schematically illustrating a PC sheet on which a conductive pattern provided with a carbon paste resistance film according to the embodiment is printed.

FIG. 3 is a partial cross-sectional view showing three examples of an embodiment of a synthetic resin molded lens according to the present invention, wherein (A) shows a state in which a PC sheet is insert-molded on the inner surface of a transparent lens;
(B) illustrates a state in which a PC sheet is insert-molded on the prism surface of the prism lens, and (C) illustrates a state in which the PC sheet is insert-molded on the outer side surface of the transparent lens.

FIG. 4 is a sectional side view for explaining a problem in a vehicle lamp using a synthetic resin lens.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lamp housing, 2 ... Synthetic resin lens, 3 ... Bulb socket, 4 ... Light source bulb, 5 ... Shade, 6 ... Snow cover, 7 ... Fine water droplets, 8 ... PC sheet, 9 ... Ag paste conduction pattern, 10a, 10b, 11a, 11b terminal, 12 anode conductive pattern, 13 cathode conductive pattern, 14 carbon paste resistive film, 15 transparent lens made of synthetic resin, 16 prism lens made of synthetic resin, 16a prism element.

Claims (1)

[Claims] 1. A lens for a vehicle lamp formed of a synthetic resin material, wherein a substantially transparent electrically insulating sheet-shaped member having a conductive pattern printed thereon is fixed to the lens surface by insert molding. A molded lens made of synthetic resin, wherein the lens surface is heated when power is supplied to the conductive pattern.