Vehicle decorative part and method for manufacturing vehicle decorative part

Abstract

To provide a vehicle decorative part having a surface appearance different from that of a conventional vehicle decorative part, in which a decorative pattern is formed by foaming a surface of a colored resin base material.SOLUTION: A vehicle decorative part 10, which is made of a colored resin and has a laser decorative pattern 30 formed on a surface with a foam layer 32, has. in the laser decorative pattern 30. a discoloration pattern formed by a discoloration layer 34 that is darker than a background color of the laser decorative pattern 30.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a vehicle decorative part in which a decorative pattern is formed by irradiating a surface of a resin molded product with a laser, and a method for manufacturing the vehicle decorative part. [Background technology]

[0002] 2. Description of the Related Art Conventionally, decorative parts for vehicles have been known in which a pattern is formed by irradiating the surface of a resin base material with a laser.

[0003] For example, in the vehicle decorative part disclosed in Patent Document 1, a reflective metal film is formed on the surface of a transparent resin substrate, and a decorative pattern is formed by irradiating a laser and peeling off part of the reflective metal film.

[0004] On the other hand, in the vehicle decorative part disclosed in Patent Document 2, a laser is irradiated onto the surface of an opaque colored resin substrate, causing the resin to melt and foam, forming a foamed layer, and a decorative pattern is formed by the color contrast between the foamed layer and the substrate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-107789 A [Patent Document 2] JP 2013-132669 A Summary of the Invention [Problem to be solved by the invention]

[0006] The decorative pattern formed by the foam layer has a whitish glossy appearance. However, in recent years, in response to consumer demand for design diversity, there has been a demand for proposals for decorative parts for vehicles that provide new appearances.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a vehicle decorative part in which a decorative pattern is formed by foaming the surface of a colored resin substrate, and which presents a surface appearance different from that of conventional decorative parts. [Means for solving the problem]

[0008] In order to achieve the above object, a vehicle decorative part according to a first aspect of the present invention has the following configuration. 1. A decorative part for a vehicle made of a colored resin and having a laser decorative pattern formed on the surface with a foam layer, wherein the laser decorative pattern has a discoloration pattern formed with a discoloration layer that is darker than the color of the foam layer.

[0009] (Effects) In conventional vehicle decorative parts in which a laser-decorated pattern is formed using a foam layer, the decorative pattern has a uniform appearance with a whitish gloss. With the above-mentioned configuration, by forming a discoloration pattern in the decorative pattern that is darker than the background color of the decorative pattern, any discoloration pattern can be expressed in the decorative pattern, and an appearance with a different impression from the whitish gloss can be presented, improving the design of the vehicle decorative part.

[0010] 2. In the above aspect 1, it is also preferable that the discoloration pattern is a striped pattern in which a plurality of thin dark lines are arranged in a predetermined direction at predetermined intervals.

[0011] (Effect) By forming a striped pattern of thin lines within the decorative pattern, it is possible to present an appearance with a different impression from a whitish gloss. In particular, by forming a striped pattern in which thin dark lines are arranged at a specific pitch, a uniform, line-grained metallic gloss is produced throughout, which particularly improves the design.

[0012] 3. In the above embodiment 1 or 2, it is also preferable that the discoloration pattern is a striped pattern in which thin lines having a width of 10 to 15 μm are uniformly arranged at intervals of 30 to 40 μm.

[0013] Moreover, a method for producing a vehicle decorative part according to a second aspect of the present invention has the following configuration. 4. (a) A step of irradiating a decorated area on the surface of a workpiece made of a colored resin with a laser to form a foam layer on the surface of a first irradiated area, and (b) A step of irradiating a second irradiated area with the laser so that the second irradiated area overlaps with at least a portion of the first irradiated area in step (a) to form a further foam layer on the surface and to form a discoloration layer in the overlapping portion between the first irradiated area and the second irradiated area, thereby forming a discoloration pattern composed of the discoloration layer within a decorative pattern composed of the foam layer.

[0014] (Action and effect) In the conventional manufacturing method for decorative parts in which a laser decorative pattern is formed using a foam layer, the laser is irradiated so that the irradiation energy exceeds the white color appearance threshold and is below the discoloration threshold, and the irradiated areas do not overlap, thereby forming a decorative pattern with a uniform, whitish glossy appearance. However, with the above configuration, any discoloration pattern can be expressed within the decorative pattern by simply making the second irradiation area at least partially overlap the area irradiated by the first irradiation, and an appearance with a different impression from the whitish gloss can be presented, thereby improving the design of decorative parts for vehicles.

[0015] 5. In the above aspect 4, it is also preferable that the output energy of the laser light, the beam spot diameter defining the first and second irradiation areas, and the irradiation line distance between the steps (a) and (b) defining the dimensions of the overlapping portion are set so that the amount of irradiation energy of the laser in the first irradiation area is equal to or greater than the white expression threshold at which the colored resin foams and turns white, but is less than the discoloration threshold at which discoloration occurs, and that in the overlapping portion, the combined energy of the accumulated energy due to irradiation of the laser light in step (a) and the irradiation energy due to irradiation of the laser in step (b) is equal to or greater than the discoloration threshold of the colored resin.

[0016] 6. In the above embodiments 4 and 5, it is also preferable that the discoloration pattern is a striped pattern consisting of a plurality of thin dark lines formed by scanning the laser light linearly in a predetermined direction in steps (a) and (b). (Effects) When the discoloration pattern is a thin striped pattern, it is possible to present an appearance that gives a different impression from a whitish gloss. In particular, by forming a striped pattern in which thin dark lines are arranged at a specified interval, a grained metallic gloss is produced, and the design is particularly improved.

[0017] 7. In the above embodiments 4 to 6, it is also preferable that the striped pattern is a striped pattern in which thin lines having a width of 10 to 15 μm are uniformly arranged at intervals of 30 to 40 μm. Effect of the Invention

[0018] According to the above aspect, it is possible to provide a vehicle decorative part that exhibits a surface appearance different from that of conventional products. [Brief description of the drawings]

[0019] [Figure 1] 1 is a front view of a vehicle lamp including a vehicle decorative part according to a first embodiment. [Diagram 2] FIG. 2A is a front view showing a schematic diagram of a laser decoration pattern formed on the surface of the vehicle decorative part, and FIG. 2B is a cross-sectional view of the same. [Diagram 3] FIG. 3 is an enlarged view of a main part of FIG. 2. [Figure 4] FIG. 2 is a block diagram showing the configuration of a laser decoration system 40 used in manufacturing the extension 10. [Diagram 5] 4A to 4C are diagrams illustrating a method for manufacturing the vehicle decorative part. [Figure 6] 1A to 1C are diagrams illustrating the mechanism by which a discoloration pattern is formed in a laser decoration pattern by the above manufacturing method. [Figure 7] 4 is a photograph of a laser-applied decorative pattern of a vehicle decorative component according to an embodiment of the present invention. [Figure 8] FIG. 8 is an enlarged photograph of a portion of the laser decoration pattern in FIG. 7. [Figure 9] FIG. 11 is a front view showing a schematic diagram of a laser decoration pattern formed on a surface of a vehicle decorative part according to a modified example of the above embodiment. [Figure 10] FIG. 11 is a front view of a vehicle headlamp equipped with a vehicle decorative part according to a second embodiment. [Figure 11] FIG. 2 is a cross-sectional view of the vehicle headlamp. [Figure 12] 4 is a photograph of a laser-decorated pattern of a vehicle decorative part according to a comparative example. [Figure 13] FIG. 11 is an enlarged photograph of a portion of the laser decoration pattern in FIG. [Figure 14] 10A and 10B are diagrams illustrating a mechanism by which a laser decorative pattern is formed by a foam layer according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. The embodiments are merely illustrative and do not limit the present invention. All of the features and combinations described in the embodiments are not necessarily essential to the present invention.

[0021] The same components and members shown in each drawing are given the same reference numerals, and duplicated explanations are omitted as appropriate. Also, in each drawing, when there are a plurality of the same components, the reference numerals are omitted as appropriate. As for the modified examples, only the modified parts from the embodiment are described, and the other parts have the same configuration as the embodiment.

[0022] In the following description, unless otherwise specified, the direction of light emitted from the vehicle lamp is the forward direction, and the directions of front, rear, up, down, left and right are described. However, the directions of front, rear, up, down, left and right are for the convenience of explanation, and the present invention is not limited to these directions when it is implemented. Furthermore, the size of each part in the drawings is shown appropriately enlarged or reduced for the convenience of explanation, and does not necessarily reflect the actual dimensions.

[0023] (First embodiment) Vehicle decoration parts The vehicle decorative part according to the first embodiment is embodied as an extension 10 used as a component part of a vehicle lamp 1. The vehicle lamp 1 shown in Fig. 1 is a right-side headlamp.

[0024] The vehicle lamp 1 includes a lamp body 12, an outer cover 14, a first lamp unit 16, a second lamp unit 18, and an extension 10.

[0025] The lamp body 12 has a container-like shape that is open at the front. The outer cover 14 covers the opening at the front of the lamp body 12, and the lamp body 12 and the outer cover 14 define a lamp chamber 2.

[0026] The first lamp unit 16 is a lamp unit for high beam. The first lamp unit 16 includes a light source 16a, which is an excitation light source such as a blue LED, and a light distribution pattern forming system 16b, which includes, for example, a condenser lens, a scanning mechanism, and a phosphor. The first lamp unit 16 is configured to emit light emitted from the light source 16a forward in a light distribution pattern formed by the light distribution pattern forming system 16b through a projection lens 16c.

[0027] The second lamp unit 18 is a lamp unit for low beam. The second lamp unit 18 also includes a light source 18a, which is an excitation light source such as a blue LED, and a light distribution pattern forming system 18b including, for example, a condenser lens, a scanning mechanism, and a phosphor. The second lamp unit 18 is configured to emit light emitted from the light source 18a forward in a light distribution pattern formed by the light distribution pattern forming system 18b through a projection lens 18c.

[0028] The extension 10 is disposed between the first and second lamp units 16, 18 and the outer cover 14. The extension 10 is formed by injection molding using an opaque colored resin.

[0029] A first opening 22 is provided on one side (the left side in FIG. 1) of the center of the extension 10. A first lamp unit 16 is disposed on the rear side of the first opening 22, and a projection lens 16c of the first lamp unit 16 can be seen from the front through the first opening 22. When the light source 16a is turned on, the irradiated light passes through the opening 26 and is emitted forward in a predetermined light distribution pattern.

[0030] A second opening 24 is provided on the opposite side of the first opening 22 from the center of the extension 10 (the right side in FIG. 1). A second lamp unit 18 is disposed on the rear side of the second opening 24, and a projection lens 18c of the second lamp unit 18 is housed in the second opening 24 so that it can be seen from the front. When the light source 18a is turned on, the irradiated light passes through the second opening 24 and is emitted forward in a predetermined light distribution pattern.

[0031] The extension 10 is formed by injection molding using opaque colored resin as a material. The resin material is preferably a thermoplastic resin such as ABS resin, PP resin (polypropylene resin), PC / ABS resin, PC resin (polycarbonate resin), PMMA resin (acrylic resin), POM resin (polyacetal resin), PBT resin (polybutylene terephthalate resin), or PET resin (polyethylene terephthalate resin). Although not limited thereto, a dark colored resin, particularly a black resin containing carbon black, is preferable from the viewpoint of the contrast between the background color of the resin substrate and the pattern of the foam layer. In addition, a black resin containing carbon black is advantageous in terms of energy efficiency by laser irradiation.

[0032] A laser decorative pattern 30 is formed on the lower part of the extension 10 outside the second opening 24 (on the right side in FIG. 1).

[0033] Fig. 2(A) is a front view showing a laser decoration pattern 30 formed on the surface of the extension 10. Fig. 2(B) is a cross-sectional view of the extension 10 taken along line IIB-IIB in Fig. 2(A), showing a schematic view of the laser decoration pattern 30. Fig. 3 is a further enlarged view of the same cross-section as Fig. 2(A).

[0034] The laser decoration pattern 30 is an area showing the letter M of the alphabet. The laser decoration pattern 30 is formed as a whole from a foam layer 32. The foam layer 32 is formed by melting and foaming the base material of the extension 10 by laser decoration. The foam layer 32 takes on a whitish color due to foaming, creating a contrast with the color of the base material, and the laser decoration pattern 30 can be recognized.

[0035] Within the region of the laser decoration pattern 30, a discoloration layer 34 is formed that is darker than the color of the foam layer 32, which is the background color of the laser decoration pattern 30. In this embodiment, the discoloration layer 34 is formed in a plurality of thin lines extending in the left-right direction when viewed from the front. The thin lines are arranged at predetermined intervals, parallel to each other, and at approximately equal intervals to form a discoloration pattern 36 that shows a striped pattern as a whole.

[0036] Although there are no limitations on the discoloration pattern 36, it is preferable that the discoloration layer 34 forms a striped pattern of thin lines with a width of 10 to 15 μm that are uniformly arranged at intervals of 30 to 40 μm on the foamed layer 32, as shown in Fig. 3. In this case, the laser decorative pattern 30 has little overall unevenness and presents an appearance with a metallic luster and line-grained texture.

[0037] Manufacturing method for vehicle decorative parts Next, a manufacturing method of the extension 10 will be described. First, a laser decoration system 40 used in manufacturing the extension 10 will be described. Fig. 4 is a configuration block diagram of the laser decoration system 40. The laser decoration system 40 includes a laser irradiation device 41, a control device 46, and a jig 53 for holding the workpiece 10W, which is the extension 10.

[0038] The laser irradiation device 41 includes a laser generating unit 42 , a laser irradiation unit 43 , a laser scanning unit 44 , and a laser control unit 45 .

[0039] The laser generating unit 42 generates pulsed laser light L. In the present embodiment, the laser generating unit 42 is a YVO4 laser with a wavelength of 1064 nm.

[0040] The laser irradiation unit 43 includes an optical system in which a lens 43a and a reflecting mirror 43b are combined, and by changing the positions of the lens 43a and the reflecting mirror 43b, the irradiation position and the focal position of the laser light L are adjusted, and the laser light L is irradiated onto the surface of the workpiece 10W. By adjusting the focal position of the laser light L, the beam spot diameter is determined.

[0041] The laser scanning unit 44 is a moving mechanism capable of moving the laser irradiation unit 43 along two orthogonal axes (the scanning direction and the traveling direction in FIG. 5). The laser scanning unit 44 moves the laser irradiation unit 43 in the scanning direction within the decorated area of ​​the workpiece 10W corresponding to the laser decoration pattern 30 in accordance with the control device 46, and scans the laser light L in the scanning direction. In addition, for each scan in the scanning direction, the laser irradiation unit 43 is moved in the traveling direction perpendicular to the scanning direction by the irradiation line interval d, and is moved to the starting point of the scanning direction. The scanning of the laser light L in the scanning direction, the movement in the traveling direction between scans, and the movement to the starting point of the scanning direction are repeated to perform scanning of the laser light L. The laser control unit 45 controls the modulation of the irradiation energy of the laser light L, etc.

[0042] The control device 46 is a well-known computer including a CPU 47, a memory 48, an input / output port (I / O) 49, etc. The CPU 47 is electrically connected to the laser irradiation device 41 and controls the laser irradiation device 41 by various drive signals. The memory 48 stores laser irradiation data 51 for performing laser irradiation. The laser irradiation data 51 is data created based on CAD data, and includes information on the decorated area corresponding to the laser decoration pattern 30. It also includes information on the scanning direction and the traveling direction. The memory 48 also stores data indicating laser irradiation parameters (such as the focal position of the laser light L, the beam spot diameter, the irradiation line interval, and the output energy).

[0043] In the above example, the laser used was a YVO4 laser with a wavelength of 1064 nm. However, this is not limited to this, and other solid-state lasers such as a YAG laser, a ruby ​​laser, and a glass laser may also be used. Also, in addition to solid-state lasers, gas lasers such as a CO2 laser, a He-Ne laser, an Ar laser, and an excimer laser may also be used.

[0044] 5A to 5C are diagrams for explaining the manufacturing method of the vehicle decorative part (extension 10) according to the present embodiment over time. The left column is a schematic diagram seen from the same cross section as in FIG. 3, and the right column is a schematic diagram seen from above.

[0045] When the operation starts, the control device 46 sets the output energy, irradiation line interval, and beam spot diameter of the laser light L in accordance with the laser irradiation parameters 52 stored in the memory 48. The laser irradiation parameters 52 may be set each time by an operator who controls the laser decoration system 40.

[0046] Next, the control device 46 reads out the laser irradiation data 51 stored in the memory 48, and controls the laser irradiation device 41 and the laser scanning unit 44 according to the laser irradiation data 51 to start irradiating the laser light L from the starting point S of the scanning direction (Figure 5(A)).

[0047] When the laser irradiation unit 43 starts irradiating the laser light L, the surface portion of the workpiece 10W melts along the first irradiation region 36a, air bubbles 33 are generated, and a foamed layer 32 is formed, as shown in FIG. 5(B).

[0048] Next, the laser irradiation device 41 moves the laser irradiation section 43 in the traveling direction by the irradiation line spacing d and also moves it to the starting point S in the scanning direction, and scans the laser light L so that the second irradiation area 36b when scanned in the scanning direction from the starting point S overlaps with at least a portion of the first irradiation area 36a (Figure 5(C)).

[0049] Then, as shown in FIG. 5(D), the foamed layer 32 expands in the direction of travel along the second irradiated area 36b, and a dark discolored layer 34 is formed in the overlapping portion of the irradiated area on the surface of the workpiece 10W.

[0050] Then, the laser irradiation device 41 moves the laser irradiation unit 43 by the irradiation line interval d in the traveling direction for each scan in the scanning direction by the laser scanning unit 44, and scans the laser light L so that the irradiation area by this scan overlaps at least a part of the irradiation area by the previous scan. In other words, the irradiation line interval d defines the size of the overlapping part. As a result, as shown in FIG. 5(E), a striped discoloration pattern 35 is formed in the laser decoration pattern 30 formed in the foam layer 32, in which a plurality of dark thin lines extending in the scanning direction are arranged in the traveling direction.

[0051] In the above description, the scanning direction of the laser scanning unit 44 is unidirectional, and the starting point of each scan is on the same side. However, the present invention is not limited to this, and the laser decoration system 40 may be configured so that the scanning direction is a reciprocating direction, and after scanning in the forward direction, the laser irradiation unit 43 is moved in the forward direction by the irradiation line interval d at that position, and scanning in the return direction is performed.

[0052] Mechanism of formation of discoloration patterns Here, referring to FIG. 6, the mechanism by which the discoloration pattern 35 is formed on the vehicle decorative part according to the present embodiment by the above-mentioned manufacturing method will be described. The left column of FIG. 6 shows the relationship between the focus of the laser light L irradiated in this embodiment and the irradiation surface (surface of the workpiece). The center column shows the relationship between the irradiation area (corresponding to the first irradiation area 36a) of the irradiated laser light L and the amount of irradiation energy accumulated in the irradiation area in one irradiation (spot). The right column shows the relationship between the beam spot diameter of the irradiated laser light L and the combined energy amount of the irradiation energy accumulated in the irradiation area when the laser light L is irradiated (spot) multiple times (three times) while shifting the irradiation position in the traveling direction. In the center and right columns, the vertical axis of the graph indicates the amount of energy accumulated in the irradiation area, and the horizontal axis indicates the irradiation position in the traveling direction.

[0053] As shown in the center column of Fig. 6, in the embodiment, a narrow range is irradiated with high energy, and the amount of irradiation energy accumulated in the irradiated area in one irradiation is an amount of energy that causes a white color to appear due to the generation of a foam layer, but does not cause discoloration to a dark color (an amount of energy that is equal to or greater than the white color appearance threshold and less than the discoloration threshold). As shown in the left column of Fig. 6, such an amount of energy is achieved by irradiating the surface of the workpiece 10W, which is the irradiated surface, so that the surface is near the focus of the laser light L. At this time, the beam spot diameter is about 60 μm, and the laser light L is irradiated with high energy in a narrow range.

[0054] As a result, as shown in the right column of Fig. 6, the energy stored in the overlapping irradiated areas is a composite energy of the stored energy from the previous (first) irradiation and the irradiated energy from the current (second) irradiation. The overlapping areas include at least an area where the composite energy amount is equal to or greater than the discoloration threshold. As a result, a discoloration layer 34 is formed only in the area where the amount is equal to or greater than the discoloration threshold. This discoloration layer 34 forms a discoloration pattern 35.

[0055] For convenience of explanation, the right diagram of FIG. 6 is drawn assuming that the irradiation energy in the first irradiation and the accumulated energy in the irradiation area of ​​the first irradiation at the time of the second irradiation do not change. However, in reality, the accumulated energy accumulated in the irradiation area attenuates over time. Therefore, it is also preferable to determine whether the amount of combined energy is equal to or greater than the discoloration threshold value by taking into consideration the attenuation of the accumulated energy over time.

[0056] In this way, the amount of irradiation energy accumulated in the irradiated area in one irradiation is an amount of energy that will cause a white color to appear due to the generation of a foam layer, but will not cause a discoloration to a dark color.When the next irradiation is performed by shifting the irradiation line interval d, the irradiation conditions are set so that the amount of combined energy of the accumulated energy from the previous irradiation and the irradiation energy from the current irradiation accumulated in the overlapping area is equal to or exceeds the discoloration threshold value at which the color changes to a darker color than the foam layer, thereby making it possible to manufacture extensions 10 having a discoloration pattern 35 formed by a discoloration layer 34 that is darker than the white color of the foam layer 32, which is the background color of the laser decoration pattern, within the laser decoration pattern 30 formed by the foam layer 32.

[0057] Example 1 Fig. 7 is a photograph of a laser decoration pattern 61 formed on an extension 60 manufactured by the manufacturing method according to the embodiment as Example 1, and Fig. 8 is a partially enlarged photograph of the laser decoration pattern of Example 1. The extension 60 according to Example 1 is formed by injection molding using a black resin containing carbon black as a material. Table 1 shows the irradiation conditions of the laser light L.

[0058] [Table 1]

[0059] As shown in FIG. 7, the laser decoration pattern 61 formed on the extension 60 of Example 1 had a discoloration pattern 62 formed by a discoloration layer that was discolored to a darker brown than the background color of the laser decoration pattern 61 within the laser decoration pattern formed of a whitish foam layer.

[0060] The discoloration pattern 62 was a striped pattern in which multiple brown thin lines 63 extending in the scanning direction were arranged in the traveling direction. As shown in Fig. 8, the width of the thin lines was 10 to 15 µm, and the intervals between them were 30 to 40 µm. The laser-decorated pattern 61 thus formed had a line-grained, metallic appearance, which differed from the laser-decorated pattern consisting only of a foamed layer shown as a comparative example at the end of this specification.

[0061] The above laser light irradiation conditions are set according to the laser irradiation system used. These conditions are set so that the amount of irradiation energy by the laser light irradiation is equal to or greater than the white color development threshold of the colored resin and less than the discoloration threshold in the irradiation area of ​​the first irradiation and the irradiation area of ​​the second irradiation, and the combined energy of the accumulated energy by the first irradiation and the irradiation energy by the second irradiation exceeds the discoloration threshold in at least a part of the overlapping part.

[0062] In the same extension as in Example 1 and in the laser irradiation system used in Example 1, if the irradiation line interval d is less than 0.03 mm, which is the radius of the beam spot, a gap will be formed between the foam layer formed by the first irradiation and the foam layer formed by the second irradiation, so it is preferable that the irradiation line interval d is smaller than the radius of the beam spot.

[0063] In addition, when the defocus amount is increased, the beam spot diameter becomes larger and the irradiation area becomes larger, so that the irradiation energy per spot is reduced, and the combined energy of the accumulated energy by the first irradiation and the irradiation energy by the second irradiation becomes smaller, which inhibits the generation of the discoloration layer, so the defocus amount is preferably 0 to 2 mm.

[0064] Furthermore, increasing the laser output would result in burning rather than discoloration, so an output energy of 5 to 6 W was preferred.

[0065] Variations 9(A) and 9(B) show laser decoration patterns 30A and 30B formed on the same extension 10 as the embodiment, as a modification of the present embodiment. As shown in FIG. 9(A), the laser decoration pattern 30A may be a stripe pattern in which the discoloration layer 34 extends in a straight line, as in the laser decoration pattern 30, but may also be a stripe pattern in which the discoloration layer 34 extends in a curved line. Also, the laser decoration pattern 30B may not necessarily be a stripe pattern with a line width of 10 to 15 μm and a uniform interval of 30 to 40 μm, but may be a stripe pattern in which lines of different thicknesses are alternately arranged in the discoloration layer 34, as in the laser decoration pattern 30B. It is possible to realize an area corresponding to such line thickness by adjusting the beam spot diameter (focus defocus amount) and the irradiation line interval d so that the amount of composite energy accumulated in the irradiation area is equal to or greater than the discoloration threshold value. In this case, the appearance is not necessarily a line grained metallic appearance, but the appearance is different from that of a conventional laser decoration pattern composed only of the foam layer 32. Therefore, even if such modifications are made, the effect of the present invention of providing a decorative part for a vehicle having a surface appearance different from that of the conventional one can be achieved.

[0066] Second embodiment The vehicle decorative part according to the second embodiment is embodied as a front cover 114 used as a component part of a vehicle lamp 100. The vehicle lamp 100 shown in Figures 10 and 11 is a right-side headlamp.

[0067] The vehicle lamp includes a box-shaped lamp body 112 that opens forward, and a front cover 114 that closes the opening of the lamp body 112. The lamp body 112 and the front cover 114 define a lamp chamber 102.

[0068] A first lamp unit 116 and a second lamp unit 118 are disposed in the lamp chamber 102. The first lamp unit 116 is a low beam lamp unit. It is configured to include a light source (not shown) that is an excitation light source such as a blue LED, and a light distribution pattern forming system 116b that includes, for example, a condenser lens, a scanning mechanism, and a phosphor, and to project light emitted from the light source forward through a projection lens 116c.

[0069] The second lamp unit 118 is a lamp unit for high beam. As shown in FIG. 11, the second lamp unit 118 generally includes a semiconductor laser element 118a, a light emitting device 118b including a wavelength conversion layer, and a projection lens 118c. The second lamp unit 118 is attached to a support member 160, which is attached to the lamp body via an optical axis adjustment mechanism 150. The second lamp unit 118 is configured to emit light emitted from the light emitting device 118b forward by the projection lens 118c.

[0070] An extension 110 is disposed between the second lamp unit 118 and the front cover 114. The front cover 114 has a horizontally elongated, approximately rectangular shape when viewed from the front. The front cover 114 has circular light-transmitting portions 114a on the left and right sides of the center, and an inverted triangular light-transmitting portion 114b in the center of the upper part. The other portions of the front cover 114 are formed with a non-light-transmitting portion 114c. The light-transmitting portions 114a and 114b are made of a light-transmitting resin such as PMMA resin or PC resin, and the non-light-transmitting portion 114c is made of a non-light-transmitting resin such as ABS resin or PP resin (polypropylene resin) containing a pigment such as carbon black. That is, the front cover 114 is formed by two-color molding of a light-transmitting resin and a non-light-transmitting resin.

[0071] A laser decoration pattern 130 consisting of the letters A, B, C, and ! is formed on the front surface of the front cover 114 at the bottom. As shown in FIG. 11, the laser decoration pattern 130 includes a foam layer 32 that is melted by a laser and foamed to show a whitish luster, and a discoloration layer 34 that is darker than the foam layer 32. The laser decoration pattern 130 is generally composed of the foam layer 32, and forms a discoloration pattern (striped pattern) in which dark thin lines composed of the discoloration layer 34 are arranged at a predetermined interval. By forming a striped pattern of thin lines within the decorative pattern, it is possible to present an appearance that gives an impression different from the whitish luster. In particular, by forming a striped pattern in which dark thin lines are arranged at a predetermined pitch, a uniform metallic luster with line grain is generated throughout, and the design is particularly improved, which is an effect unique to the present invention.

[0072] As shown in a partially enlarged view in FIG. 11, a hard coat 138 is applied to the front surface of the front cover 114 including the laser decoration pattern 130. As the hard coat 138, various hard coats available on the market, such as acrylic or silicone hard coats consisting of acrylic monomers, ultraviolet absorbers, light stabilizers, polymerization initiators, and solvents, can be used. The laser decoration pattern 130 made of the foam layer 32 has a foamed surface, so the surface strength is weak. When the vehicle decoration part according to this embodiment is embodied as a member exposed to the outside, such as the front cover 114 of this embodiment, it is preferable to apply the hard coat 138 in this way to ensure the surface strength.

[0073] In the above embodiment, the extension 10 provided on the right-side headlamp and the front cover 114 are described, but the present invention is not limited to this and can be applied to resin molded products including extensions provided on various vehicle lamps, vehicle lamp parts such as front covers having opaque parts, rear windows having opaque parts, various panels, and other vehicle parts.

[0074] Comparative Example Finally, as a comparative example, a conventional vehicle decorative part that is formed only of a foam layer and does not include a color-changing layer will be described.

[0075] Fig. 12 is a photograph of a laser decoration pattern 91 formed on an extension 90 according to Comparative Example 1, and Fig. 13 is a partially enlarged photograph of Fig. 12. The extension according to Comparative Example 1 has the same configuration as the extension 60 according to Example 1, except for the laser decoration pattern 91. Comparative Example 1 is manufactured by the same method as Example 1, except for the laser light irradiation conditions (specifically, the irradiation point interval, the focal defocus amount, and the beam spot diameter). [Table 2]

[0076] As shown in Fig. 10, in the laser decoration pattern 91 formed on the extension 90 of the comparative example, the irradiation lines are not noticeable, and no stripes are visible from a distance, and the whole has a uniformly foamed whitish appearance. Also, as shown in Fig. 11, the scanning lines are not noticeable even when enlarged.

[0077] FIG. 14 is a diagram for explaining the mechanism by which a laser decorative pattern 91 is formed in a comparative example. As in FIG. 6, the left column of FIG. 14 shows the relationship between the focus of the irradiated laser light L and the irradiated surface (surface of the workpiece). The center column shows the relationship between the irradiation area of ​​the irradiated laser light L and the amount of irradiation energy accumulated in the irradiation area in one irradiation (spot). The right column shows the relationship between the beam spot diameter of the irradiated laser light L and the combined energy amount of the irradiation energy accumulated in the irradiation area when the laser light L is irradiated (spot) multiple times (three times) while shifting the laser light L. In the center and right columns, the vertical axis of the graph shows the amount of energy accumulated in the irradiation area, and the horizontal axis shows the irradiation position in the traveling direction.

[0078] As shown in the center column of Fig. 14, in the comparative example, the laser light L is irradiated with low energy over a wide range. For this reason, as shown in the left column of Fig. 14, the focal position of the laser light L is set so that the focal point of the laser light L is away upward from the surface of the workpiece W10, which is the irradiated surface (the focal point is defocused). As a result, the beam spot diameter becomes about 100 μm, and the laser light L is irradiated with low energy over a relatively wide range. At this time, the amount of irradiation energy accumulated in the irradiated area is an energy amount that causes a white color to appear due to the generation of a foam layer, but does not cause a discoloration to a dark color (an energy amount that is equal to or greater than the white color appearance threshold and less than the discoloration threshold).

[0079] Then, as shown in the right column of Fig. 14, when the scanning position is shifted by the irradiation line interval d and a second irradiation is performed, the energy stored in the overlapping irradiation area is a composite energy of the accumulated energy from the previous (first) irradiation and the irradiation energy from the current (second) irradiation, but the amount of the composite energy does not exceed the discoloration threshold. Therefore, no discoloration layer is formed, and the entire decorative pattern has a uniform whitish glossy appearance.

[0080] The above describes preferred embodiments of the present invention. However, the above embodiments are merely examples of the present invention, and these can be combined based on the knowledge of those skilled in the art. Such combinations are also included within the scope of the present invention. [Explanation of symbols]

[0081] 10W: Work 30: Laser decoration pattern 32: Foam layer 34: Discoloration layer 35: Discoloration pattern 36: Discoloration pattern 36a: First irradiation area 36b: second irradiation area 61: Laser decoration pattern 62: Discoloration pattern 63: Thin line L: Laser light d: Irradiation line interval

Claims

1. It is made of colored resin, A vehicle decorative part having a laser decorative pattern formed of a foam layer on a surface thereof, A decorative part for a vehicle, comprising: a laser-decorated pattern having a discoloration pattern formed therein by a discoloration layer that is darker than the background color of the laser-decorated pattern.

2. 2. The decorative part for a vehicle according to claim 1, wherein the discoloration pattern is a striped pattern in which a plurality of thin dark lines are arranged in a predetermined direction at predetermined intervals.

3. 3. The decorative part for a vehicle according to claim 1, wherein the discoloration pattern is a striped pattern in which thin lines having a width of 10 to 15 μm are arranged at intervals of 30 to 40 μm.

4. (a) irradiating a laser beam onto a region to be decorated on a surface of a workpiece made of a colored resin to form a foam layer on the surface of a first irradiation region; (b) applying the laser light so that a second irradiation region overlaps at least a part of the first irradiation region in the step (a), thereby forming a foam layer on the surface and forming a color-changing layer in the overlapping portion between the first irradiation region and the second irradiation region; A method for manufacturing a decorative part for a vehicle, comprising forming a color-changing pattern constituted by the color-changing layer within a decorative pattern constituted by the foam layer.

5. The output energy of the laser light, the beam spot diameter defining the first and second irradiation areas, and the irradiation line interval between the step (a) and the step (b) defining the size of the overlapping portion are In the first and second irradiation regions, the amount of irradiation energy by the irradiation of the laser light is equal to or greater than the white color development threshold of the colored resin and less than the color change threshold, The method for manufacturing a decorative part for a vehicle according to claim 4, characterized in that in at least a portion of the overlapping portion, a combined energy of the accumulated energy due to the irradiation of the laser light in step (a) and the irradiation energy due to the irradiation of the laser in step (b) is set to exceed the discoloration threshold value.

6. 6. The method for manufacturing a decorative part for a vehicle according to claim 4 or 5, characterized in that the discoloration pattern is a striped pattern consisting of a plurality of thin dark lines formed by scanning the laser light linearly in a predetermined direction in steps (a) and (b).

7. 7. The method for manufacturing a decorative part for a vehicle according to claim 6, wherein the striped pattern is a striped pattern in which thin lines having a width of 10 to 15 μm are uniformly arranged at intervals of 30 to 40 μm.

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