Vehicle lamp and method for manufacturing vehicle lamp

Abstract

To increase regular reflectance of a part having a reflector function in a holder member holding a light guide and lower regular reflectance of the other parts to less than the regular reflectance of the part having a reflector function.SOLUTION: A vehicle lamp includes: a light source; a light guide for guiding light from the light source; and a holder member provided with a recess for holding the light guide. The holder member is an injection molding of a resin material. The resin material includes a thermoplastic resin, a white pigment, and a filler. The filler has a particle size of 6-8 μm and an aspect ratio of 12-17. The thickness of a portion of the holder member forming the recess for holding the light guide is thicker than those of the other parts of the holder member.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle lamp and a method for manufacturing the vehicle lamp. [Background technology]

[0002] In recent years, the interiors of vehicle lamps have become more complex, leading to a demand for resin parts with complex shapes and small sizes. For this reason, the use of polypropylene, which has higher fluidity than polycarbonate, to manufacture vehicle lamps has been considered. Furthermore, the use of light guides in vehicle lamps is expanding to improve design, and studies are being conducted to equip holder members that hold light guides with reflector functionality, which reflects light leaking from the light guide to increase the output efficiency of the lamp light. Such holder members are required to reflect visible light from LED light sources without transmitting or absorbing it. For this reason, the use of white pigments in the resin parts that make up the holder members is being studied. For example, it is known that a resin material containing polypropylene as the main component and inorganic fillers such as talc and white pigments is used for housing members of vehicle lamps (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2023 / 189746 Summary of the Invention [Problem to be solved by the invention]

[0004] In the recess of the holder member that holds the light guide, the portion that functions as a reflector is required to have a high regular reflectance in order to increase the output efficiency of the lamp light. On the other hand, other parts of the holder member may be decorative surfaces that can be seen through the outer cover of the vehicle lamp. For such decorative surfaces, a matte texture with low specular reflectance is preferred over a glossy surface with high specular reflectance.

[0005] One way to reduce the specular reflectance of the design surface of the holder component is to use a texturing process. However, texturing is costly. Also, when texturing is applied, the texturing surface adheres to the mold during demolding, which can lead to demolding problems.

[0006] The present invention aims to provide a vehicle lamp and a manufacturing method thereof, in which the specular reflectance of the portion of a holder member that holds a light guide and that functions as a reflector is high, while the specular reflectance of other portions is lower than the specular reflectance of the portion that functions as a reflector. [Means for solving the problem]

[0007] A vehicle lamp according to one aspect of the present invention comprises: A light source and a light guide that guides light from the light source; a holder member provided with a recess for holding the light guide; Equipped with the holder member is an injection-molded product made of a resin material, the resin material includes a thermoplastic resin, a white pigment, and a filler; The particle size of the filler is 6 to 8 μm, and the aspect ratio of the filler is 12 to 17, The thickness of the portion of the holder member that forms the recess is thicker than the other portions of the holder member.

[0008] Another aspect of the present invention is A light source and a light guide that guides light from the light source; a holder member provided with a recess for holding the light guide; A method for manufacturing a vehicle lamp comprising: a step of producing the holder member by injection molding a resin material including a thermoplastic resin, a white pigment, and a filler; The particle size of the filler is 6 to 8 μm, and the aspect ratio of the filler is 12 to 17, In the injection molding of the holder member, the flow rate of the resin material in the portion where the recess is formed is set to be faster than the flow rate of the resin material in other portions of the holder member. [Effects of the Invention]

[0009] According to the present invention, when a holder member is manufactured by injection molding of a resin material containing a filler having a particle size of 6 to 8 μm and an aspect ratio of 12 to 17, a thermoplastic resin, and a white pigment, the thickness of the portion of the holder member that forms the recess that holds the light guide can be made thicker than the other portions of the holder member, thereby making the specular reflectance of the recess higher than the specular reflectance of the other portions of the holder member. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a diagram showing a vehicle lamp according to an embodiment of the present invention; [Figure 2] FIG. 2 is a cross-sectional view taken along the line II-II in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. For the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0012] First, a vehicle lamp 1 according to an embodiment will be described with reference to Fig. 1. Fig. 1 is a front view showing the vehicle lamp 1 including a holder member 10, and Fig. 2 is a cross-sectional view taken along the line II-II in Fig. 1. The vehicle lamp 1 includes a lamp body 22 and a transparent outer cover 24 that covers the front opening of the lamp body 22. Note that the outer cover 24 is not shown in Fig. 1. The lamp body 22 and the outer cover 24 form a lamp chamber 26.

[0013] The vehicle lamp 1 includes one or more beam units 28, a holder member 10, and a light guide 20 in a lamp chamber 26. In the illustrated example, the light guide 20 functions as a DRL (Daytime Running Lamp).

[0014] The light guide 20 is a long, rod-shaped member and is held in a recess 11 of the holder member 10. In FIG. 1, the light guide 20 extends from the lower right to the left of the vehicle lamp 1 and then extends toward the upper left. One end of the light guide 20 (the right end in FIG. 1) penetrates the back surface of the holder member 10, and the end face of one end of the light guide 20 faces the light source 30 arranged on the back surface of the holder member 10. Light from the light source 30 enters the light guide 20 from the end face. The light guide 20 guides the light from the light source 30 while emitting part of the light via steps formed inside. The light guide 20 is not particularly limited, but is preferably made of a thermoplastic resin having a total light transmittance of 85% or more at a thickness of 3 mm.

[0015] 1, the holder member 10 extends leftward from the lower right of the vehicle lamp 1 and then extends upward and leftward. The holder member 10 includes a recess 11 and a flat portion 12. The flat portion 12 is an example of an "other portion" of the holder member 10 other than the recess 11.

[0016] The recess 11 is formed along the light guide 20, and extends leftward from the lower right of the vehicle lamp 1 and further extends upward and leftward. The light guide 20 is held in the recess 11. 2, the recess 11 has an arc-shaped cross section corresponding to the circular cross section of the light guide 20. The surface (front surface) of the recess 11 also functions as a reflective surface that reflects the light emitted from the light guide 20 forward. The flat portion 12 is the portion other than the recessed portion 11 on the front surface of the holder member 10 shown in Fig. 1. As shown in Fig. 2, the thickness T2 of the holder member 11 at the flat portion 12 is thinner than the thickness T1 of the holder member 11 at the recessed portion 11. The shape of the holder member 10 shown in FIGS. 1 and 2 is an example, and the shape of the holder member 10 of the present invention is not limited to this.

[0017] The vehicle lamp 1 is not particularly limited as long as it includes the holder member 10. The vehicle lamp 1 can be suitably used, for example, as an automobile headlamp, fog lamp, position lamp, rear combination lamp, turn signal lamp, or various lamps that notify pedestrians and drivers of other vehicles of the status of the vehicle (for example, that the vehicle is being driven autonomously).

[0018] The holder member 10 is a member made of a resin part with a reflectance of 70% or more for light with a wavelength of 400 to 700 nm. The holder member 10 holds a long light guide 20 and has a recess 11 configured to be able to reflect light emitted from the light guide 20. Since the recess 11 is made of a resin part with the above reflectance, it can efficiently reflect light emitted from the light guide 20 held in the recess 11.

[0019] The resin parts that make up the holder member 10 include a thermoplastic resin, a filler, a white pigment, etc. The holder member 10 can be manufactured by injection molding a resin material that includes a thermoplastic resin, a white pigment, and a filler. Examples of thermoplastic resins that can be used include polyethylene, polypropylene, polyester, polystyrene, etc. Among these, polypropylene is preferably used. The polypropylene may be a homopolymer, copolymer, block polymer, random polymer, or the like, but is preferably a polypropylene composed of a homopolymer and a copolymer. The polypropylene preferably has a melt flow rate (MFR) of 10 g / 10 min to 60 g / 10 min when extruded at 230°C and 21 N. Resin parts containing polypropylene with such physical properties have a lower specific gravity and higher fluidity than polycarbonate, making it possible to mold lightweight resin parts with complex shapes or large sizes.

[0020] Fillers are added to resin parts to improve their strength and heat resistance. In this embodiment, the particle diameter of the filler is preferably 6 to 8 μm, and the aspect ratio is preferably 12 to 17. Here, the "particle diameter" is the diameter of a circle equal to the projected area of ​​the particle (area-equivalent diameter). The volume-average diameter can be used as the average primary particle diameter. The aspect ratio is the ratio b / a of the major axis diameter a to the minor axis diameter a of the filler. The "minor axis diameter" refers to the smallest distance between two parallel lines tangent to the outline of a particle (projected image) when a particle is thrown onto a horizontal plane and observed in its most stable state from a direction perpendicular to the plane, and the "major axis diameter" refers to the distance measured in a direction perpendicular to the minor axis diameter.

[0021] When the particle size of the filler is 6 to 8 μm and the aspect ratio is 12 to 17, the filler is oriented according to the injection speed when the resin material containing the filler is injection molded. If the filler is regularly oriented on the surface of the molded body, the surface of the molded body shrinks uniformly, resulting in a smooth surface for the resin part after shrinkage. This results in a resin part with a surface with high specular reflectance.

[0022] When the resin parts constituting the holder member 10 are manufactured by injection molding, it is preferable that the filling speed of the resin material in the portions that will become the recesses 11 is faster than the filling speed of the resin material in the portions that will become the flat portions 12. The faster the filling speed of the resin material, the more regularly the filler is oriented. Therefore, by making the filling speed of the resin material in the portions that will become the recesses 11 faster than the filling speed of the resin material in the portions that will become the flat portions 12, the surface of the recesses 11 can be made smoother than the surface of the flat portions 12. Therefore, the specular reflectance of the surface of the recesses 11 can be made higher than the specular reflectance of the surface of the flat portions 12.

[0023] On the other hand, if the filling speed of the resin material is slow, the filler is difficult to orient, which tends to result in a low specular reflectance and a high diffuse reflectance. Therefore, by slowing down the filling speed of the resin material in the portion that will become the flat portion 12, the specular reflectance on the surface of the flat portion 12 can be reduced, resulting in a matte texture.

[0024] By making the thickness of the portion that becomes the recess 11 thicker than the thickness of the portion that becomes the flat portion 12, the filling speed of the resin material in the portion that becomes the recess 11 can be made faster than the filling speed of the resin material in the portion that becomes the flat portion 12. Therefore, by making the thickness T1 of the recess 11 of the holder member 10 thicker than the thickness T2 of the flat portion 12, the specular reflectance on the surface of the recess 11 can be made higher than the specular reflectance on the surface of the flat portion 12.

[0025] The amount of filler added is preferably 10 wt % or more and 40 wt % or less, and more preferably 20 wt % or more and 40 wt % or less, based on the total weight of the resin part.

[0026] As the filler, talc, glass fiber, calcium carbonate, mica, wollastonite, etc., can be used. Among these, it is preferable to use talc, which is excellent in terms of improving heat resistance, improving dimensional accuracy, and cost. The preferred particle size of talc is a side length of 1 μm to 30 μm and a thickness of 10 nm to 500 nm. The particle size of talc is preferably 6 to 8 μm. Here, the particle size of talc is the diameter of a circle equal to the projected area of ​​the particle (area-equivalent diameter). The volume-average diameter can be used as the average primary particle diameter. The aspect ratio of the talc is preferably 12-17.

[0027] As the white pigment, titanium oxide, aluminum oxide, zinc oxide, lithopone, white lead, etc. may be used, but it is preferable to use titanium oxide, which is excellent in terms of light-shielding properties, reflectivity, and cost. The preferred average primary particle diameter of the white pigment is 50 nm to 500 nm. Here, the particle diameter of the pigment is the diameter of a circle equal to the projected area of ​​the particle (area-equivalent diameter). The volume-average diameter can be used as the average primary particle diameter. The amount of white pigment added is preferably 0.5 wt% to 10 wt% of the entire resin part, and more preferably 1 wt% to 5 wt%. By using the above formulation, the reflectance of the resin part for light with a wavelength of 400 to 700 nm can be increased to 70% or more, thereby preventing the transmission of visible light. Here, "reflectance" refers to the sum of specular reflectance and diffuse reflectance. The specular reflectance of the resin part for light with a wavelength of 400 to 700 nm is preferably 2% or more.

[0028] The resin parts that make up the holder member 10 preferably contain a light stabilizer. When ultraviolet light acts on polypropylene, polypropylene radicals are generated. When oxygen acts on these polypropylene radicals, hydroperoxides are generated, which cut the polypropylene molecular chains and degrade the polypropylene, causing cracks in plastic parts. On the other hand, if the resin part contains a light stabilizer, the light stabilizer reacts with the polypropylene radicals and restores the polypropylene to its original state. Therefore, if the resin part contains a light stabilizer in addition to the white pigment, the effects of ultraviolet light scattered by the white pigment can be reduced.

[0029] The light stabilizer preferably has a melting point of 120° C. or higher. The light stabilizer is not particularly limited, but Tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate (CAS registration number: 91788-83-9), Tetrakis(2,2,6,6-tetramethyl-4-piperidyl)butane-1,2,3,4-tetracarboxylate (CAS registration number: 64022-61-3), Bis(2,2,6,6-tetramethyl-4-piperidyl)sebaceate (CAS registration number: 52829-07-9), Poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-pipe (CAS registration number: 71878-19-8), 2,2,6,6-tetramethylpiperidin-4-yl hexadecanoate (CAS registration number: 85916-01-4), 2,2,6,6-tetramethylpiperidin-4-yl octadecenoate (CAS Registry Number: 24860-22-8) It is preferable to use at least one of the above light stabilizers in the resin part. The content of the light stabilizer is preferably 500 to 2000 ppm relative to the total amount of the resin part. By setting the content within this range, it is possible to suppress deterioration of the resin part due to ultraviolet rays, improve light resistance, and suppress the occurrence of cracks on the surface of the resin part while maintaining the reflectance of the resin part.

[0030] The resin parts constituting the holder member 10 preferably further contain a heat resistance improver. The heat resistance improver is not particularly limited, but an antioxidant can be used. Specifically, hindered phenol-based antioxidants such as pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) (IRGANOX® 1010 manufactured by BASF Japan Ltd.) and 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (IRGANOX® 3114 manufactured by BASF Japan Ltd.) can be used. The content of the heat resistance improver is preferably 100 to 2000 ppm relative to the entire resin part. By setting the content within this range, excellent heat resistance can be ensured in the holder member 10 having the function of a reflector.

[0031] It is preferable that the resin parts constituting the holder member 10 further contain an ultraviolet absorber. By employing resin parts containing an ultraviolet absorber, excellent light resistance can be ensured in the holder member 10 having the function of a reflector. The melting point of the ultraviolet absorber is preferably 120° C. or higher. By using an ultraviolet absorber with a melting point of 120° C. or higher, the light resistance of the reflective material can be improved without causing the lamp lens to fogging up.

[0032] The ultraviolet absorber is not particularly limited, but 2-(2H-Benzotriazol-2-yl)-4,6-bis(1-methyl-1-phenylethyl)phenol (CAS registration number: 70321-86-7), 2,2'-Methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol] (CAS registration number: 103597-45-1), 2-(5-chloro-2H-benzotriazol-2-yl)-6-tert-butyl-4-methylphenol (CAS registration number: 3896-11-5), 2,4,6-tris(2-hydroxy-4-hexyloxy-3-methylphenyl)-1,3,5-triazine (CAS Registration Number: 222529-65-9)) 3,5-Di-tert-butyl-4-hydroxybenzoic acid 2,4-di-tert-butylphenyl ester (CAS Registry Number: 4221-80-1) At least one of the above ultraviolet absorbers is preferably used in the resin part.

[0033] The content of the ultraviolet absorber is preferably 100 to 3000 ppm relative to the total weight of the resin parts constituting the holder member 10. While maintaining the reflectance of the resin parts, the light resistance is improved, deterioration of the resin parts due to ultraviolet rays is suppressed, and the occurrence of cracks on the surfaces of the resin parts can be suppressed.

[0034] The flexural modulus of the resin parts constituting the holder member 10 is preferably 2 MPa or more and 5 MPa or less. Furthermore, the deflection temperature under load of the resin parts at a bending stress of 0.45 MPa is preferably 120° C. or more and 140° C. or less. By using such resin parts, excellent strength and heat resistance can be ensured in the holder member 10 having the function of a reflector.

[0035] The specific gravity of the resin parts that make up the holder member 10 is 0.89 g / cm 3 More than 1.30g / cm 3It is preferable that the melt flow rate (MFR) of the resin part when extruded at 230°C and 21 N is 3 g / 10 min or more, and more preferably 10 g / 10 min to 60 g / 10 min. Resin parts with such physical properties have a lower specific gravity and higher fluidity than conventional polycarbonate materials, so that even if the resin part has a complex shape or is large, it is easy to reduce the thickness, and the resin part can be molded at a lightweight.

[0036] It is preferable that the resin parts constituting the holder member 10 have a color with a yellowness index YI in the range of -10 to -0.4. Furthermore, upconversion nanoparticles that absorb light with wavelengths longer than 640 nm and emit light at around 475 nm may be used as an additive to reduce the yellowish tint. By using such upconversion nanoparticles, the yellowish tint in the reflected light can be reduced, resulting in a bluish light emission.

[0037] The resin parts constituting the holder member 10 preferably have a flexural modulus of elasticity of 2 GMPa or more and 5 GMPa or less. The mold shrinkage rate of the resin parts that make up the holder member 10 is preferably 1.0% or more and 1.5% or less. It is preferable that the deflection temperature under load of the resin part constituting the holder member 10 against a bending stress of 0.45 MPa is 120°C or more and 140°C or less.

[0038] The holder member 10, which holds a long light guide 20 and has a recess 11 configured to reflect light emitted from the light guide 20, also becomes large in size according to the length of the light guide 20. Therefore, if a resin material with low fluidity is used, the member will be thick and heavy. If a resin material with a high specific gravity is used, the weight will also increase. However, because the resin parts that make up the holder member 10 have a low specific gravity and exhibit high fluidity during molding, the holder member 10 with reflector function can be made thin and lightweight.

[0039] Furthermore, a holder member 10 having an edge 14 that borders an opening 15 configured to allow insertion of another member, and having a recess 11 that functions as a reflector provided along at least a portion of the edge 14, has a more complex shape. Therefore, if a resin material with low fluidity is used, the member will be thicker and heavier. By using the above-mentioned specific resin parts in such a holder member 10 with a complex shape, a holder member 10 that functions as a reflector and is made of a material with a low specific gravity can be suitably configured.

[0040] [Experimental Example] A resin material was created by kneading polypropylene as the base resin with talc, white pigment, light stabilizer, and light resistance agent.The resin material was injection molded while changing the injection rate (g / s) to create resin parts. The particle size of the talc used was 6 to 8 μm, and the aspect ratio was 12 to 17. The specular reflectance and diffuse reflectance of the surface of the obtained test piece of the resin product were measured. The results are shown in Table 1.

[0041] [Table 1]

[0042] As shown in Table 1, the higher the injection rate, the higher the specular reflectance and the lower the diffuse reflectance. The higher the injection rate, the faster the injection speed of the resin material. The faster the injection speed, the more regularly the talc is oriented. If the talc is regularly oriented, the surface will shrink uniformly when the molded body is cooled after being demolded. This results in a smooth surface for the resin part after shrinkage, and a higher specular reflectance.

[0043] Although the embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be construed as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents. [Explanation of symbols]

[0044] 1: Vehicle lamp, 10: Holder member, 11: Recess, 12: Flat portion, 20: Light guide, 22: Lamp body, 24: Outer cover, 26: Lamp chamber, 28: Beam unit

Claims

1. A vehicle lamp, A light source and a light guide that guides light from the light source; a holder member provided with a recess for holding the light guide; Equipped with the holder member is an injection-molded product made of a resin material, the resin material includes a thermoplastic resin, a white pigment, and a filler; The particle size of the filler is 6 to 8 μm and the aspect ratio is 12 to 17; a thickness of a portion of the holder member that forms the recess is greater than a thickness of other portions of the holder member; Vehicle lighting fixtures.

2. 2. The vehicle lamp according to claim 1, wherein the thickness of the portion of the holder member where the recess is formed is at least twice the average thickness of the remaining portion of the holder member.

3. 2. The vehicle lamp according to claim 1, wherein the thermoplastic resin is polypropylene.

4. 2. The vehicular lamp according to claim 1, wherein the filler is at least one selected from the group consisting of talc, glass fiber, calcium carbonate, mica, and wollastonite.

5. 2. The vehicular lamp according to claim 1, wherein the white pigment is at least one selected from the group consisting of titanium oxide, aluminum oxide, zinc oxide, lithopone, and white lead.

6. A light source and a light guide that guides light from the light source; a holder member provided with a recess for holding the light guide; A method for manufacturing a vehicle lamp comprising: a step of producing the holder member by injection molding a resin material including a thermoplastic resin, a white pigment, and a filler; The particle size of the filler is 6 to 8 μm, and the aspect ratio of the filler is 12 to 17, In the injection molding of the holder member, a flow rate of the resin material in a portion where the recess is formed is set to be faster than a flow rate of the resin material in other portions of the holder member. A method for manufacturing a vehicle lamp.

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