JP3061095B2 - Signal lamp lens and molding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens for a traffic light used for a traffic light, and more particularly to a signal light lens which prevents discrimination at the time of turning on and off a signal light due to harmful light from the outside. The present invention relates to a signal lamp lens capable of reducing light / dark unevenness (luminance unevenness) of a lens surface (light emitting surface) at the time of lighting.

[0002]

2. Description of the Related Art A signal lamp usually comprises a light source lamp 1 having a filament 2 on its inner surface, a reflecting mirror 3 ,
And a lens 4 arranged in front of the light source lamp 1 . The signal lamp device, when the light source lamp 1 is turned on, part of the light 5 emitted from the full <br/> Iramento 2 is reflected by the reflecting mirror 3, emitted through further lens 4, the light 6 Is visually recognized by drivers and pedestrians.

[0003] However, in the above conventional signal lighting device,
As shown in FIG. 2, when a solar ray 7 enters the interior from behind the driver or the like through the lens 4 , the incident light 7 is reflected by the reflecting mirror 3 to become light 8, and passes through the lens from the signal lamp. Emitted again. For this reason, there has been a problem that a so-called pseudo-lighting phenomenon occurs in which a driver or a pedestrian sees the signal light as though it is lit even when the signal light is turned off.

As a solution to the above-mentioned problems, a large light-shielding hood in the form of a hat is attached to the upper front of the signal light body, or a checkered plate is installed in front of the signal light lens. When viewed from above, there is an inconvenience that the visibility becomes poor such that the signal lamp lens cannot be seen unless the angle is within the driver's viewing angle.

In addition, for example, in the method disclosed in Japanese Patent Publication No. 4-77359, a minute convex lens is used as shown in FIG.
9 and a plurality of lens portions having a light blocking plate 10 disposed on the focal plane of the convex lens are disposed inside the concave mirror, and harmful light 11 incident from the outside is absorbed by the light blocking plate, thereby preventing erroneous recognition. Has been proposed. However, this method has a problem that a plurality of lens units, for example, about 150 lens units are required, the whole apparatus becomes complicated, and assembly adjustment is difficult.

When a driver or a pedestrian of an automobile sees a signal lamp, the driver looks at the brightness of the surface of the reflecting mirror 3 by the light source lamp 1 through the front lens 4. In addition to the light distribution and chromaticity, it is necessary to reduce uneven brightness (uneven brightness) on the lens surface (light emitting surface).

In order to reduce uneven brightness on the lens surface of the signal lamp, a light source lamp (white light bulb) with a white paint applied to the inner surface of the bulb as a light source lamp, or a small convex projection provided on the inner surface of the lens may be used. The light is diffused moderately by applying fine cutting, but when using a white painted light bulb, the wattage of the light source lamp inevitably increases to obtain the required luminous intensity. There was a point.

When a transparent light source lamp, that is, a transparent light bulb, is used to obtain the necessary luminous intensity as a signal lamp, the luminous intensity in the central axis direction increases. Only a part of the (light-emitting surface) appears to glow brightly. Further, there is a problem that a ring-shaped light and dark pattern appears even from the front of the signal lamp when the light bulb is mounted slightly shifted from a predetermined position.

As a method of imparting light diffusing performance to the lens surface, there is a method of applying a paint containing a light diffusing agent to a lens molded product. However, since the lens has a curved surface, a liquid pool of the paint and dust and dirt are removed. The occurrence of appearance defects due to adhesion becomes extremely high. In addition, a method of dispersing an inorganic filler such as glass fiber, calcium carbonate, silica or the like is generally used in order to obtain a light diffusion effect with a molding material. However, when the surface appearance, heat resistance, hydrolysis resistance, and impact resistance are required for the light-diffusing substrate, there is a decrease in impact resistance due to hydrolysis in a conventional inorganic filler dispersed therein,
I can no longer respond.

As a method for imparting light diffusing performance to the lens surface, there is a method in which a paint containing a light diffusing agent is applied to a lens molded product by an immersion method, a spray coating method, a flow coater method or the like. Therefore, appearance defects due to paint pools and dust adhesion become extremely high.

On the other hand, a method in which a diffusing agent is added to a molding material for molding a lens may be used, but in this case, the resulting molded article is obtained in a state where the diffusing agent is dispersed inside the molded article. Due to the compounding, the diffusing agent is buried in the molding material. For this reason, external light rays are not reflected and diffused on the surface of the molded product, and external light is incident on the reflecting mirror in the signal lamp, and it is difficult to prevent false lighting.

[0012]

DISCLOSURE OF THE INVENTION The present invention prevents the traffic signal light lens from being erroneously recognized as being illuminated by the sunlight, and reduces uneven brightness of the lens surface when the signal light is lit. Polycarbonate signal light lens with excellent hydrolysis resistance, impact resistance, fluidity, etc.
And a method for molding the same.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, after mounting a polycarbonate sheet containing a light diffusing agent in a mold cavity, a molding material is obtained. The inventor has found that the above-mentioned problems can be solved by injecting the heat-melted polycarbonate onto the sheet and integrally molding the same, thereby completing the present invention. That is, the present invention is a signal lamp lens formed by injection molding, after mounting a polycarbonate sheet containing a light diffusing agent on at least one surface of the mold cavity, and then injecting the heated and melted polycarbonate into the mold. The present invention relates to a synthetic resin signal lamp lens obtained by integral molding.

Since the polycarbonate sheet used in the present invention contains a light diffusing agent at the time of manufacturing the PC sheet, it does not require any treatment such as painting, and therefore has no problem such as a liquid pool of the paint and has a beautiful appearance. Therefore, it is suitable for molding a lens requiring surface appearance performance.

Since the organic filler fine particles of the light diffusing agent are compounded at the time of manufacturing the polycarbonate sheet, there is no stagnation in the molding process and material deterioration due to heat history as compared with the case where it is compounded in the injection molding material. No worry about discoloration. In addition, since filler does not remain in the molding machine cylinder during work such as material change, material change can be easily performed.

The thickness of the polycarbonate sheet is not particularly limited, but is preferably 0.1 mm to 2.0 mm from the viewpoint of improving the product surface appearance and moldability. By using a sheet having a thickness in the above range, it is possible to prevent the occurrence of wrinkles on the surface of the sheet at the final filling portion and to maintain good moldability in the case where the mold cavity shape is formed by vacuum molding or the like.

The light diffusing agent to be incorporated into the polycarbonate sheet of the present invention is preferably fine particles of organic fillers, such as fine particles of styrene-cyclohexylmaleimide, fine particles of styrene-cyclohexylmaleimide copolymer containing titanium oxide, and fine particles of acrylic. Crosslinked fine particles, non-crosslinked acrylic fine particles, non-crosslinked styrene fine particles, and the like can be exemplified. Particularly, crosslinked acrylic fine particles are preferable, and the addition amount of the crosslinked fine particles to the polycarbonate sheet is in the range of 1 to 5% by weight in terms of transmittance and diffusivity. Is desirable. If the addition ratio of the light diffusing agent is less than the above, a predetermined effect cannot be expected, while if the addition ratio exceeds the above, there is a problem in terms of transmittance.

The polycarbonate sheet having light diffusion performance can be formed by a usual sheet forming method, for example, an extrusion forming method.

When the sheet to be used is mounted on the outer surface facing the reflection surface of the lens, at least one of weather resistance, antistatic property and antifogging property can be imparted. Addition of functions is weather resistance, antistatic property,
It can be carried out by mounting a polycarbonate sheet having a coating having excellent antifogging properties on one side into a mold and then injecting a molding material into the mold.
-250927, JP-A-60-253518, JP-A-60-523516, and JP-A-61-5
No. 910 can be used.

As for the polycarbonate used as an injection molding material in the present invention, a polycarbonate sheet needs to be weldable, but in general, the same composition can be easily welded. Even in the case of a polycarbonate mixed with an additive having light diffusion performance, polarization performance, infrared absorption performance, ultraviolet absorption performance, etc., the adhesive strength between the material and the sheet is 5 k at a 90 degree peel strength.
It has an adhesive strength of g / cm or more. Also, when the types of additives of the molding material and the sheet are different, the adhesive performance is not reduced, and the performance as a lens is further improved.

As the molding material used in the present invention, the above polycarbonates having excellent impact resistance are used. Among them, aromatic polycarbonates having a molecular weight of 15.0
Those having a value of about 00 to 25,000 are desirable.

When the lens of the present invention is molded in a mold, a sheet provided with a functional film on one surface is mounted with the functional film facing the mold surface. By mounting on both sides of the mold cavity, a molded product having a surface treatment film at the same time in the molding process can be obtained. The sheet that has been surface-treated on one side is mounted in a cavity with the treated side facing the mold side.

As a mounting method, a gate or a tab portion of a sheet obtained by punching into a mold cavity shape by a press machine is punched in advance and fixed to a pin provided in the mold.
Attaching an iron piece to the sheet tab portion and mounting it by a known method of mounting a magnet embedded in the mold portion at the same position, or mounting by molding a sheet previously shaped by vacuum forming etc. in the mold cavity shape .

The molding conditions may be generally known conditions, but preferably, the resin temperature is set to 260 ° C. or higher to obtain a perfect adhesive strength, and the mold temperature is set in the range of 30 ° C. to 120 ° C. By doing so, the cooling time can be reduced. Normal conditions can be applied to the injection compression molding, and the molding of a thin lens molded product can be easily performed by compressing the resin at a surface pressure of 200 to 1000 kgf / cm ² immediately after injecting the resin into the mold.
Further, surface transfer can be improved as compared with injection molding.

As shown in FIG. 4, the signal light lens according to the present invention emits harmful light 11 incident from the outside by sunlight.
Light rays are reflected and diffused by the diffusion layer 12 formed on the lens surface to become light 13 , so that light entering the signal lamp can be reduced, and a pseudo lighting phenomenon can be prevented.

Further, as shown in FIG. 5, light emitted from the light source lamp is reflected by a reflecting mirror in the signal lamp and becomes emitted light via a lens. The diffusion layer formed on the lens surface at this time
The light 14 is diffused by the light 12 to provide an appropriate light distribution, thereby preventing uneven brightness (uneven brightness) on the lens surface.

[0027]

The present invention will be described below in detail with reference to examples. In Examples and the like,% represents% by weight, and the following physical properties were adopted for each physical property value. The total light transmittance and the diffusivity were measured by using a direct reading haze computer (manufactured by Suga Test Instruments). The lens surface appearance was visually evaluated. The pseudo-lighting phenomenon was determined by making a model of a signal lamp and visually checking the state of a reflecting mirror in the signal lamp with respect to light emitted from a light source assuming incoming sunlight. Izod impact strength was measured based on ASTM D-256 (notched). Pressure cooker test (PTC) processing is 14
The treatment was performed for 8 hours in a high-pressure steam atmosphere at 0 ° C. (2.7 atm).

Examples 1 and 2 The injection molding machine was manufactured by Mitsubishi Heavy Industries, Ltd., Model: 150 MST
Was used. As a mold, a disk lens mold having a cavity 15 shown in FIG. 6 having a thickness of 3 mm and a diameter of 100 mmφ was used. A 0.3 mm thick polycarbonate sheet 16 containing acrylic crosslinked fine particles (Rohm & Haas Paraloid EXL-5136) mixed at a ratio shown in Table 1 as a light diffusing agent in one cavity 15 of a mold is formed into a cavity shape by a press machine. Attached after cutting. Next, polycarbonate resin material 17 (Mitsubishi Gas Chemical Co., Ltd.)
Product name: Iupilon S-3000, molecular weight: 22,
000) was injected under the conditions of a resin temperature of 300 ° C., a mold temperature of 60 ° C., and an injection pressure (gauge pressure: 600 kgf / cm ² ) to obtain a disk-shaped molded product 18 shown in FIG. The molding material and the sheet were integrated by the heat and pressure of molding to obtain a laminated molded article having a light diffusion layer formed on the surface. Table 1 shows the evaluation results.

Comparative Example 1 Using the same mold as in Example 1, the same molding material (product name: Iupilon S-3000, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used in the same manner as in Example 1 without mounting a sheet. The molding was performed under the following molding conditions to obtain a disk-shaped molded product. Table 1 shows the evaluation results.

Comparative Example 2 The same molding material (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon S-3000) was used in the same mold as in Example 1 without mounting a sheet. Molding was performed under the same molding conditions to obtain a disk-shaped molded product. Then, in order to perform a diffusion treatment on the molded article, a light diffusion treatment was performed on the surface of the molded article by a dipping method in a paint containing a diffusing agent, and a light diffusion film was baked in a dryer at 100 ° C. Table 1 shows the evaluation results.

Comparative Example 3 Using the same mold as in Example 1, without mounting a sheet, the same molding material (Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon S-3000) was used as a light diffusing agent. Acrylic cross-linked fine particles (Rohm & Haas, product name: Pararoad EXL-51)
Using a molding material containing 0.5% by weight of 36), molding was performed under the same molding conditions as in the example to obtain a disk-shaped molded product. Table 1 shows the evaluation results.

Comparative Example 4 Using the same mold as in Example 1, the same molding material (trade name: Iupilon S-3000, manufactured by Mitsubishi Gas Chemical Co., Ltd.) was used without attaching a sheet, and fine powdered calcium carbonate was used. 1.5% by weight (trade name: Sipron A, manufactured by Sibro Chemical Co., Ltd.) and titanium oxide (trade name: JR-600A, manufactured by Teikoku Processing Co., Ltd.)
Using a molding material containing 0.5 wt%, molding was performed under the same molding conditions as in Example 1 to obtain a disk-shaped molded product. Table 1 shows the evaluation results.

[0033]

Table 1 Example, Comparative Example No. Real 1 Real 2 Ratio 1 Ratio 2 Ratio 3 Ratio 4 Sheet composition (%) PC 90.0 95.0---- Light diffusing agent 1.0 5.0 ----Molding material composition (%) PC 100.0 100.0 100.0 100.0 99.5 98.0 Light diffusing agent----0.5-Calcium carbonate-----1.5 Titanium oxide-----0.5 Light transmittance (%) Total light 17.2 16.2 17.8 15.6 16.0 14.3 Diffused light 10.3 14.5 0.2 12.0 13.5 13.7 Appearance Liquid pool No No No Yes No No Dust adhered No No No Yes No No Pseudo lighting phenomenon Small Very small Many Small Many Many Izod impact strength (Kg-cm / cm) Before PCT treatment 81 83 88 79 82 56 PCT After treatment 75 76 80 73 71 7 Evaluation Good Excellent Not possible Not possible Not possible Not possible Notation: Abbreviations in the table PC; Polycarbonate PCT; Pressure cooker test

[0034]

According to the lens for a signal lamp of the present invention, since light diffusion performance can be imparted only to the surface layer of a lens molded product, harmful light incident from the outside due to sunlight is emitted by the light diffusion layer formed on the lens surface. It is possible to reduce the amount of light that is reflected and diffused into the signal lamp, thereby preventing a pseudo lighting phenomenon. Further, light emitted from the light lamp of the signal lamp is reflected by a reflecting mirror in the signal lamp and becomes outgoing light via a lens. At this time, the light is diffused by the diffusion layer formed on the lens surface, and the light is distributed properly, so that uneven brightness (uneven brightness) on the lens surface can be prevented. ADVANTAGE OF THE INVENTION The lens for signal lights of this invention can provide light diffusing property without using special equipment, and the effect of quality improvement and cost reduction was obtained. Furthermore,
Since a light diffusing film can be provided at the time of molding, post-steps can be omitted and liquid pool defects can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a conventional signal light device.

FIG. 2 is a conceptual diagram illustrating a pseudo lighting phenomenon in a signal light device.

FIG. 3 is a conceptual diagram for explaining a pseudo lighting phenomenon in the related art.

FIG. 4 is a conceptual diagram illustrating prevention of a pseudo lighting phenomenon according to the present invention.

FIG. 5 is a conceptual diagram illustrating prevention of uneven brightness on the lens surface of the signal light device according to the present invention.

FIG. 6 is a schematic cross-sectional view showing an injection state of a molding material of the signal lamp lens of the present invention.

FIG. 7 is a sectional view of a signal lamp lens obtained by the molding method of the present invention.

[Explanation of symbols]

 1: Light source lamp 2: Filament 3: Reflecting mirror 4: Lens 5: Light from filament 6: Light emitted from signal device 7: Sunlight 8: Sunlight reflected by the reflecting mirror of signal lamp 9: Convex lens 10: Shield plate 11: Harmful light (sunlight) 12: Light diffusion layer 13: Reflected diffused light 14: Diffused light 15: Mold cavity 16: Sheet 17: Resin material 18: Molded product

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FIB29L 11:00 (56) References JP-A-64-69319 (JP, A) JP-A-63-315217 (JP, A) JP-A-60-195515 (JP, A) JP-A-60-250926 (JP, A) JP-A-60-250925 (JP, A) JP-A-60-253519 (JP, A) JP-A-61-5910 (JP, A) JP, A) JP-A-60-250927 (JP, A) JP-A-59-24642 (JP, A) JP-A-5-298595 (JP, A) JP-A-5-310956 (JP, A) Hei 2-120702 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G08G 1/095 B29C 45/14-45/16 G02B 1/04 G02B 3/00

Claims (8)

(57) [Claims] 1. A signal lamp lens formed by injection molding, wherein a polycarbonate sheet mixed with a light diffusing agent is mounted on at least one surface of a mold cavity, and then the heated and melted polycarbonate is injected into the mold. Synthetic resin signal light lens obtained by integral molding. 2. The lens for a signal lamp according to claim 1, wherein the polycarbonate sheet is mounted on the side forming the outer surface of the mold cavity. 3. The lens for a signal lamp according to claim 1, wherein the light diffusing agent incorporated in the polycarbonate sheet is an organic filler. 4. The lens according to claim 1, wherein the amount of the light diffusing agent added to the polycarbonate sheet is 1 to 5% by weight. 5. The polycarbonate sheet having a thickness of 0.
The lens for a signal lamp according to claim 1 or 2, which is 1 to 2.0 mm. 6. The signal lamp lens according to claim 1, wherein the polycarbonate sheet and / or the polycarbonate injected into the mold contains an additive having an ultraviolet absorbing property. 7. The lens according to claim 2, wherein one surface of the sheet to be used has at least one functional film having weather resistance, antistatic performance, and anti-fog performance. 8. A method for molding a lens for a signal lamp, comprising:
A method for molding a synthetic resin signal lamp lens, comprising: mounting a polycarbonate sheet containing a light diffusing agent on at least one side of a mold cavity;