Resin molded article, vehicle lamp, and method for producing resin molded article

Abstract

The present invention makes laser light irradiation marks inconspicuous in a laser decoration region. Provided is a resin molded article (10) wherein a light-blocking coating film (30) is formed on a surface of a light-transmissive resin base material (20). The resin molded article (10) has a laser decoration region (40) in which the light-blocking coating film (30) is not formed. In the laser decoration region (40), recesses (41) are formed to constitute a uniform pattern.

Description

Resin molded product, vehicle lamp, and method for manufacturing resin molded product

[0001] The present disclosure relates to a resin molded product, and more particularly to a laser-decorated resin molded product, a vehicle lamp including the same, and a method for manufacturing the resin molded product.

[0002] BACKGROUND ART Conventionally, resin molded products that are laser-decorated by providing a light-shielding coating on the surface of a light-transmitting base material and removing the coating with a laser, and vehicle lamps that use such resin molded products to enhance their design are known.

[0003] Specifically, in Patent Document 1, a resin molded product is formed on the surface of a translucent resin substrate, and a decorative pattern is formed by removing part of the reflective metal film by irradiating it with laser light, and the resin molded product is used as an inner lens or extension for a vehicle lamp.

[0004] In addition, in Patent Document 2, a resin molded product in which a metal layer and a colored layer are formed on the surface of a translucent resin substrate, and a decorative pattern is formed by removing at least a portion of the metal layer and the colored layer by irradiating them with laser light, is used as an extension or outer lens of a vehicle lamp.

[0005] JP 2019-107789 A JP 2010-192217 A

[0006] However, when removing a light-shielding coating by irradiating it with laser light, the light-transmitting base material may be damaged, and irradiation marks such as linear grooves along the direction of irradiation, scattered small holes, and scorch marks may appear on the surface of the decorative area, resulting in a problem of poor appearance of the product.

[0007] The present invention has been made in consideration of the above circumstances, and aims to provide a resin molded product in which irradiation marks from laser light are not noticeable even when there are irradiation marks from laser light in the laser decorated area, a vehicle lamp using the same, and a method for manufacturing the resin molded product.

[0008] In order to achieve the above object, a resin molded article according to one aspect of the present invention has the following configuration: 1. A resin molded article in which a light-shielding coating is formed on the surface of a light-transmitting resin substrate, the resin molded article having a laser-decorated area where the light-shielding coating is not formed, and in which recesses constituting a uniform pattern are formed.

[0009] (Effects) In a laser-decorated area formed on a resin molded product having a light-shielding coating formed on its surface, the light-shielding coating is removed, leaving the light-transmitting resin substrate exposed. Irradiation marks from the laser decoration may remain on the surface of the laser-decorated area. Forming a uniform pattern on the surface of this laser-decorated area can give the impression of a surface with a uniform pattern overall. Even if irradiation marks remain, the uniform pattern stands out, making the irradiation marks less noticeable, improving the appearance of the resin molded product. Furthermore, poor appearance can be reduced, improving product yield and reducing production costs. Furthermore, the uniform pattern can impart a new grained design to the laser-decorated area.

[0010] 2. In the above aspect 1, it is also preferable that the recesses form a uniformly formed dot pattern.

[0011] 3. In the above aspect 1, it is also preferable that the recesses form a uniform checkerboard pattern.

[0012] 4. In the above aspects 1 to 3, it is also preferable that the light-shielding coating comprises a colored layer and a light-shielding layer.

[0013] A vehicle lamp according to another aspect of the present invention has the following configuration: 5. It includes the resin molded product according to any one of aspects 1 to 4 above.

[0014] 6. In the above aspect 5, it is also preferable that the optical fiber display device further comprises a light source, an outer lens, and an inner lens or an extension disposed between the light source and the outer lens, the inner lens or the extension being the resin molded product, and the light-blocking coating is disposed on a surface facing the outer lens.

[0015] 7. In the above aspect 5, it is also preferable that the lamp further comprises a light source and an outer lens, the outer lens being the resin molded article, and the light-blocking coating is disposed on a surface facing the light source.

[0016] A method for producing a resin molded product according to yet another embodiment of the present invention has the following configuration: 8. It comprises: (a) preparing a light-transmitting resin substrate of a predetermined shape having a light-shielding coating formed on its surface; (b) irradiating the surface of the light-transmitting resin substrate with laser light to form a laser-decorated region where the light-shielding coating has been removed; and (c) irradiating the laser light onto the laser-decorated region to modify the surface of the laser-decorated region and form recesses, thereby forming a uniform pattern.

[0017] (Effects) The resin molded product manufactured by the method according to the eighth aspect above can achieve the same effects as the resin molded product according to the first aspect above. Furthermore, in the above method, the formation of the laser decoration area (b) and the formation of the recess (c) are performed using the same laser irradiation device, so there is no need to move the workpiece or prepare a separate device, and manufacturing costs can be reduced. Furthermore, the formed recess has the same effect as a so-called grain, but can be formed without using a mold, which also reduces manufacturing costs.

[0018] 9. In the above aspect 8, in (c), it is also preferable that the laser light is irradiated so that the uniform pattern becomes a dot pattern.

[0019] 10. In the above aspect 8, in (c), it is also preferable that the laser light is irradiated so that the uniform pattern forms a lattice pattern.

[0020] 11. In the aspect 8 above, it is also preferable that the step (c) includes forming the recesses by scanning the laser light in a direction perpendicular to the scanning direction of the laser light irradiation in the step (b).

[0021] 12. In aspect 8 above, it is also preferable that the light-shielding coating is composed of a colored layer and a light-shielding layer, and (b) comprises (b-1) scanning the laser light in a first direction to remove the colored layer, and (b-2) scanning the laser light in a second direction perpendicular to the first direction to remove the light-shielding layer, and that in (c) the recesses are formed by scanning the laser light in a direction perpendicular to the second direction in (b).

[0022] According to the above aspect, it is possible to provide a resin molded product in which irradiation marks from laser light are not noticeable even when they are present in the laser-decorated decorative area, a vehicle lamp using the same, and a method for manufacturing the resin molded product.

[0023] FIG. 1 is a schematic perspective view of a resin molded product according to a first embodiment of the present invention. FIG. 2 is an enlarged view of the surface of the resin molded product. FIG. 3 is an enlarged cross-sectional view of the resin molded product. FIGS. 4(a) to 4(d) are diagrams illustrating steps in a manufacturing method for the resin molded product. FIG. 4 is an enlarged view of the surface of an intermediate of the resin molded product in the manufacturing method. FIG. 5 is an enlarged view of the surface of a resin molded product according to a second embodiment of the present invention. FIG. 6 is an enlarged cross-sectional view of the resin molded product. FIGS. 8(a) to 8(d) are diagrams illustrating steps in a manufacturing method for the resin molded product. FIG. 7 is an enlarged cross-sectional view of a resin molded product according to a third embodiment of the present invention. FIGS. 10(a) to 10(d) are diagrams illustrating steps in a manufacturing method for the resin molded product. FIG. 8 is a front view of a vehicle lamp according to a fourth embodiment of the present invention. FIG. 9 is a diagram illustrating a cross-sectional structure of an inner lens and its periphery constituting the vehicle lamp. FIG. 10 is a front view of a vehicle lamp according to a fifth embodiment of the present invention. FIG. 11 is a diagram illustrating the cross-sectional structure and function of an outer lens and its periphery constituting the vehicle lamp. FIG. 11 is a front view of a vehicle lamp according to a sixth embodiment of the present invention. FIG. 12 is a photograph of an experimental example of a resin molded product manufactured under various conditions. 1 is a photograph of an experimental example of a resin molded product manufactured under various conditions.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic portions enlarged for convenience in order to make the features easier to understand, and the dimensional ratios of each component may not necessarily be the same as those in reality. Furthermore, the materials exemplified in the following description are merely examples, and the present invention is not necessarily limited to them. Appropriate changes can be made within the scope of the present invention.

[0025] In addition, in each embodiment, components having the same function are given the same names, and components having the same configuration are given the same reference numerals, and descriptions thereof are omitted as appropriate. Furthermore, when the same components are included multiple times in the same drawing, the reference numerals are omitted as appropriate.

[0026] First embodiment: resin molded product 10 FIG. 1 is a schematic perspective view of a resin molded product 10 according to a first embodiment of the present invention, FIG. 2 is an enlarged front view of the resin molded product, and FIG. 3 is an enlarged cross-sectional view taken along line III-III in FIG. 2.

[0027] The resin molded article 10 according to the first embodiment includes a light-transmitting resin substrate (hereinafter referred to as the light-transmitting substrate) 20 formed in a predetermined shape, and a light-shielding coating 30 that covers at least a portion of one surface (front surface) of the light-transmitting substrate 20. The shape of the light-transmitting substrate 20 is not particularly limited and can be changed as appropriate depending on the application. In the description of this embodiment, a rectangular plate-shaped light-transmitting substrate 20 is exemplified.

[0028] The surface of the resin molded product 10 is formed with an area where the light-shielding coating 30 is formed (light-shielding area SA) and a laser-decorated area 40 (light-transmitting area PA) where the light-shielding coating 30 is not formed. The laser-decorated area 40 is an area where the light-shielding coating 30 has been removed by laser light L. In the illustrated example, the laser-decorated area 40 is rectangular.

[0029] The material for the light-transmitting substrate 20 is a light-transmitting resin such as a polycarbonate resin or an acrylic resin such as polymethyl methacrylate. The light-transmitting resin is preferably colorless and transparent, but is not limited to this and may be a colored, transparent resin colored in red, orange, or the like. A conventionally known colorant can be used to color the light-transmitting resin.

[0030] The light-shielding coating 30 is a light-shielding colored paint film in a dark color such as black, brown, or gray. The colored paint that forms the colored paint film may be any conventionally known paint, such as an acrylic resin paint or a UV-curable acrylic resin paint. Any colored paint may be used as long as it absorbs the energy of the laser beam and is removed from the surface of the light-transmitting resin. The thickness of the light-shielding coating is, for example, about 15 to 25 μm.

[0031] As shown in Figures 2 and 3, multiple recesses 41 of uniform diameter, depth, and spacing are formed in the laser-decorated region 40. The recesses 41 form a uniformly formed dot pattern overall. Note that a "uniformly formed dot pattern" does not require that the diameter and spacing be strictly equal; it is sufficient that the dots are visually uniform. Each dot may be elliptical or circular, as shown. The size of each dot is not limited, but it is preferable that the diameter a is 0.2 to 0.5 mm and the spacing (the distance between the centers of the dots) b and c is 0.4 to 0.8 mm.

[0032] Next, an example of a method for manufacturing the resin molded product 10 will be described with reference to Fig. 4. In Fig. 4(a) to (d), the left drawings are cross-sectional views showing the same cross section as Fig. 2, and the right drawings are front views.

[0033] In summary, the resin molded product 10 is manufactured by irradiating a workpiece W, which is a light-transmitting substrate 20 of a predetermined shape on which a light-blocking coating 30 is formed, with laser light L using a laser decoration system.

[0034] The laser decoration system includes a laser irradiation device 50, a control device, and a jig for fixing the workpiece W. The laser irradiation device 50 includes a laser generating unit, a laser head, and a scanning unit. The laser generating unit generates pulsed laser light L. The laser generating unit uses an infrared laser with a peak wavelength in the infrared region. In order to remove the light-shielding coating 30, which is a colored paint layer, and to modify the surface of the light-transmitting substrate 20 to form the recesses 41, a CO 2 laser with a wavelength of 10.64 μm is used. ２ It is preferable to use a laser.

[0035] The laser head adjusts the irradiation position and focal length of the laser light L using an optical system that combines lenses and reflecting mirrors, and irradiates the laser light L onto the workpiece W.

[0036] The scanning unit is a movement mechanism capable of moving the laser head in two orthogonal directions. The scanning unit moves the laser head from the starting point in a first direction at a set irradiation speed to scan with the laser light. After completing scanning in the first direction, the laser head returns to the starting point and moves in the second direction by a set irradiation line interval. Then, at that position, the scanning unit is configured to scan with the laser light L in the first direction.

[0037] The control device is a so-called computer including a CPU, memory, input / output ports, etc. The control device is electrically connected to the laser generating unit, the laser head, and the scanning unit, and controls the laser generating unit, the laser head, and the scanning unit to irradiate a set irradiation position with laser light at a set output and irradiation speed.

[0038] To manufacture the resin molded product 10, first, as shown in FIG. 4(a), a light-transmitting base material 20 of a predetermined shape with a light-shielding coating 30 formed on its surface is prepared as a workpiece W. The light-transmitting base material 20 is formed by molding the above-mentioned light-transmitting resin into a predetermined shape by injection molding. The light-shielding coating 30 is formed by applying the above-mentioned colored paint to the surface of the light-transmitting base material 20 by a conventionally known method such as spray painting. In the workpiece W, a laser-decorating area 40 and a corresponding area to be decorated 60 are registered in a control device.

[0039] 4(b), the surface of the workpiece W is irradiated with laser light L to selectively remove the irradiated light-shielding coating 30. Specifically, as shown in the right diagram, the laser head of the laser irradiation device 50 is scanned in the X direction from a starting point S to irradiate the entire length of the decorated region 60 in the X direction, then returns to the starting point S, moves in the Y direction perpendicular to the X direction by a predetermined irradiation line interval α, and then scans in the X direction, thereby sequentially removing the light-shielding coating 30 in the decorated region 60. The irradiation conditions for this laser irradiation device are, for example, an output of 12 to 20 W and an irradiation line interval α of 0.05 mm.

[0040] Next, the laser-decorated region 40 from which the light-shielding coating 30 has been removed is irradiated with laser light L to modify the surface of the laser-decorated region 40 and form recesses 41, thereby forming a uniform dot pattern. Specifically, for example, as shown in (c) of Figure 4, the dot pattern is formed by scanning the laser light L from a starting point S in a Y direction perpendicular to the X direction. After irradiating the entire length in the Y direction, the laser head returns to the starting point S and moves a predetermined irradiation line interval β in the X direction, and similarly scans in the Y direction at that position.

[0041] To achieve the desired depth of the recesses 41, the laser may be scanned multiple times at the same X-direction position. This process is repeated sequentially to form a uniform dot pattern throughout the entire laser-decorated area 40. The size and spacing of each dot can be adjusted by changing the output power, scanning speed, and inter-irradiation line irradiation power scanning speed of the laser irradiation device 50. For example, when using a 20 W laser irradiation device, suitable conditions are 12 to 16 W, a scanning speed of 2000 mm / s or more, and an irradiation line spacing of 0.4 mm. The depth of the recesses 41 can also be adjusted by changing the number of repetitions of scanning the laser light L at the same X-direction position (hereinafter referred to as the number of prints). A suitable number of prints is 5 to 10. These conditions are set appropriately depending on the laser irradiation device used and the colored paint and transparent resin used as materials.

[0042] In the above description, the laser irradiation device 50 used is assumed to be movable in both the X and Y directions at a set scanning speed. However, if a laser processing device that can scan in only one direction and only offset the irradiation line spacing in the other direction is used as the laser irradiation device 50, the workpiece W may be rotated 90° using a jig to enable scanning in both directions.

[0043] In this way, as shown in Fig. 4(d), it is possible to manufacture a resin molded article 10 in which a uniform dot pattern is formed in the laser-decorated region 40. In particular, by irradiating the laser light under the conditions described in Fig. 4(c), it is possible to manufacture a resin molded article 10 in which a uniform dot pattern is formed with the above-mentioned suitable size and spacing.

[0044] 4(b), in the intermediate product WI from which the light-shielding coating 30 has been removed, thin grooves 91 along the scanning direction, small dot-like holes 92, and scorch marks (not shown) may remain as irradiation marks 90, as shown in FIG. 5. This has been a problem in the past, and it deteriorates the appearance of the product, and depending on the severity, it can result in an unacceptable appearance and a low product yield.

[0045] In the resin molded product 10 according to this embodiment, a uniform pattern (dot pattern) is formed on the surface of the laser-decorated region 40. As a result, even if laser irradiation marks remain in the laser-decorated region 40, the uniform dot pattern creates a striking appearance. This makes it possible to make the irradiation marks less noticeable and improve the appearance of the laser-decorated region. Furthermore, since it is possible to reduce appearance defects, the yield of products using the resin molded product 10 can be improved and production costs can be reduced. Furthermore, because the uniform pattern is fine, it is possible to give the laser-decorated region 40 a grained design that is visible to the naked eye.

[0046] In the resin molded product 10, it is preferable that the dot diameter a is 0.2 to 0.5 mm and the intervals b and c (the distance between the centers of the dots) are 0.4 to 0.8 mm. This is because if the dot diameter a is too small, it will blend in with the irradiation marks 90, reducing the effect of making the irradiation marks less noticeable, and if it is too large, the dots will stand out and will not be able to achieve the appearance and effect of grain. Also, if the intervals b and c are too small, the dots will be too close together, which could cause the recesses 41 to overlap, making it impossible to form a dot pattern, and if they are too large, the irradiation marks 90 will remain between the dots, reducing the effect of making the irradiation marks 90 less noticeable.

[0047] Although not essential, it is advantageous if the scanning direction in FIG. 4C is perpendicular to the scanning direction in FIG. 4B, since the thin grooves 91 of the irradiation marks 90 are divided by dots, making the irradiation marks 90 less noticeable.

[0048] Furthermore, the above method allows the laser decoration described in (b) of Figure 4 and the formation of the recess 41 described in (c) of Figure 4 to be performed using the same laser irradiation device 50, so manufacturing costs are not increased.

[0049] In addition, in the resin molded product 10, the laser-decorated region 40 where the light-shielding coating 30 is not formed transmits light as a light-transmitting region PA, while the region where the light-shielding coating 30 is formed blocks light as a light-shielding region SA. Therefore, when the resin molded product 10 is disposed in front of a light source, when viewed from the front, when the light source is off, the light-shielding region SA has the color tone of a colored paint, and the light-transmitting region PA has an appearance that gives the impression of a uniform grain. Furthermore, when the light source is on, only the light-transmitting region PA is emphasized, giving an appearance that is different when the light source is off and when it is on. This point will be described in detail in the explanation of the fourth to sixth embodiments.

[0050] Second embodiment: resin molded product 10A Fig. 6 is an enlarged front view of a resin molded product 10A according to a second embodiment, and Fig. 7 is a cross-sectional view taken along line VII-VII in Fig. 6. The resin molded product 10A has substantially the same configuration as the resin molded product 10, except that in the laser decoration region 40A, the recesses 42, 43 are straight lines, and the uniform pattern formed by the recesses 42, 43 is a lattice pattern.

[0051] Specifically, the resin molded product 10A has a plurality of recesses 42, 43 formed therein, each having a uniform line width and depth and with uniform spacing between the lines. The recesses 42, 43 form a uniform grid pattern overall. Note that a "uniform grid pattern" does not require that the line widths and spacings be strictly equal, but rather that the grid pattern be visually perceived as uniform. Furthermore, although not limited thereto, it is preferable that the width d of the lines constituting the grid be approximately 0.03 to 0.05 mm, and the spacing e between the lines be approximately 0.2 to 0.3 mm.

[0052] By setting the width within this range, the appearance of the uniform grid pattern is improved. If the line width is narrower than this, the effect of making the irradiation marks 90 less noticeable is weak, and if it is wider than this, there is a risk that it will not be possible to form a grid due to the relationship with the line spacing.

[0053] Next, a method for manufacturing the resin molded product 10A will be described with reference to Fig. 8. The resin molded product 10A is manufactured by irradiating a laser beam onto a light-transmitting substrate 20 having a predetermined shape and having a light-blocking coating 30 formed thereon, using a laser decoration system equivalent to that in the first embodiment.

[0054] As with the resin molded product 10, the resin molded product 10A is manufactured by preparing a workpiece Wa, which is a light-transmitting substrate 20 of a predetermined shape with a light-shielding coating 30 formed on its surface, as shown in Fig. 8(a). Next, as shown in Fig. 8(b), the workpiece Wa is irradiated with laser light L to selectively remove the light-shielding coating 30 at positions where the laser light L has been irradiated. The details are the same as in Fig. 4(b).

[0055] Next, the laser-decorated region 40A from which the light-shielding coating 30 has been removed is irradiated with laser light L to modify the surface of the laser-decorated region 40A and form recesses 42 and 43, thereby forming a uniform lattice pattern.

[0056] 8(c-1), the laser beam L is scanned from a starting point S in a Y direction perpendicular to the X direction to form linear recesses 42 in the Y direction. After irradiating the entire length in the Y direction, the laser head returns to the starting point S, moves the irradiation line interval α set in the X direction, and performs scanning in the Y direction at that position in the same manner. In order to form recesses 42 and 43 to the desired depth, the laser beam may be scanned in the Y direction multiple times at the same position in the X direction.

[0057] Next, as shown in (c-2) of Fig. 8, this time, the laser head is moved in the X direction perpendicular to the Y direction from the starting point S while scanning with the laser light L, thereby forming linear recesses 43 perpendicular to the linear recesses 42. In this way, a uniform lattice pattern is formed in the laser-decorated region 40A, as shown in the right diagram of (d) of Fig. 8.

[0058] The irradiation conditions for forming a uniform lattice pattern are, for example, a transparent and colorless polycarbonate resin for the light-transmitting substrate 20, a CO 2 lamp with an output of 20 W, ２ When a laser is used, the output is 6 to 8 W, the scanning speed is 700 to 1000 mm / s, and the irradiation line interval is 0.2 to 0.3 mm. These conditions can be adjusted depending on the laser irradiation device used, the materials of the light-transmitting resin and the colored paint, etc., and scanning may be repeated multiple times at the same position in the X direction to obtain the desired depth of the recesses 42, 43, as in the resin molded product 10. The preferred number of printing times is 2 to 10 times.

[0059] By forming the checkered pattern uniformly in this way, the checkered pattern as a whole presents an impressive design, and even if there are traces of irradiation with the laser light, they are less noticeable.

[0060] Third Embodiment: Resin Molded Product 10B Next, a resin molded product 10B according to a third embodiment of the present invention will be described. Fig. 9 is an enlarged cross-sectional view of the resin molded product 10B.

[0061] The resin molded article 10B has the same configuration as the resin molded article 10 according to the first embodiment, except that it includes a laminated light-shielding coating 30B instead of the single-layer light-shielding coating 30. That is, although not shown, a rectangular laser-decorated area 40B where no light-shielding coating 30 is formed is also formed on the surface of the resin molded article 10B. Furthermore, in the laser-decorated area 40B, a dot pattern constituted by formed recesses 41 is formed, similar to the resin molded article 10 according to the first embodiment.

[0062] The light-shielding coating 30B includes a colored layer 31 and a light-shielding layer 32. The colored layer 31 is a colored coating film in a color other than black, such as white, red, yellow, or blue. Conventionally known colored paints, such as acrylic resin paints or UV-curable acrylic resin paints, can be used as the colored coating film. The light-shielding layer 32 is a dark-colored light-shielding coating film, such as black or brown. Conventionally known light-shielding paints, such as acrylic resin paints or UV-curable acrylic resin paints, can also be selected as the light-shielding coating film.

[0063] Next, a method for manufacturing the resin molded product 10B will be described with reference to Fig. 10. Like the resin molded product 10, the resin molded product 10B is also manufactured by irradiating a light-transmitting base material 20 having a predetermined shape and having a light-blocking coating 30B formed thereon with laser light L using the same laser decoration system as in the first embodiment.

[0064] As shown in FIG. 10A, the resin molded product 10B is manufactured by first preparing a workpiece Wb, which is a light-transmitting base material 20 having a predetermined shape and having a light-shielding coating 30B formed on its surface.

[0065] Next, the surface of the workpiece Wb is irradiated with laser light L to selectively remove the light-shielding coating 30B at the irradiated positions. Specifically, as shown in (b-1) of Figure 10, starting from a starting point S, the laser light L is scanned over the entire length of the decorated region 60B in the Y direction. Next, returning to the starting point S, the laser head is moved by the irradiation line interval α set in the X direction, and scanning in the Y direction is performed at that position in the same manner. This process is repeated to remove the colored layer 31 in the decorated region 60B.

[0066] Next, returning to the starting point S, as shown in (b-2) of Figure 10, the laser light L is scanned in the X direction perpendicular to the Y direction, irradiating the entire length in the X direction of the decorated region 60. Then, while moving the laser head by the irradiation line interval α set in the Y direction, scanning in the X direction is sequentially repeated to remove the light-shielding layer 32 in the decorated region 60B.

[0067] Next, as in (c) of Fig. 4, as shown in (c) of Fig. 10, the laser light L is scanned from the starting point S in the Y direction perpendicular to the X direction, scanning the entire length of the laser decoration region 40B in the Y direction to form recesses 41 on the surface of the light-transmitting substrate 20. Then, while moving the laser head by the set irradiation line interval β, scanning in the Y direction is sequentially repeated to form a dot pattern on the surface of the light-transmitting substrate 20. In this way, as shown in (d) of Fig. 10, a uniform dot pattern similar to that of the resin molded product 10 is formed in the laser decoration region 40B.

[0068] 10(b-1) and 10(b-2), a resin molded article 10B that achieves the same effect as the resin molded article 10 can be manufactured by irradiating the laser light L in two stages as described in (b-1) and (b-2) of Fig. 10. Furthermore, after removing the light-shielding coating 30B, if the irradiation direction of the laser light L for forming the recesses is scanned in the direction in which the laser light L was last irradiated in removing the light-shielding coating 30B, that is, the Y direction perpendicular to the X direction in this example, the recesses are formed so as to divide the irradiation marks 90 of the thin grooves, making the irradiation marks 90 less noticeable.

[0069] The resin molded product 10B manufactured in this manner can also achieve the same effects as the resin molded product 10 according to the first embodiment.

[0070] In this embodiment, the irradiation conditions of the laser irradiation device 50 for forming the recess 41 in FIG. 10(c) are the same as those described for FIG. 4(c). On the other hand, the irradiation conditions of the laser irradiation device 50 for removing the light-shielding coating in FIGS. 10(b-1) and 10(b-2) require higher output power compared to those described for FIG. 4(b). This is because, in this embodiment, colored paints other than black, such as white, red, yellow, and blue, are used for the colored layer 31. In this case, the absorption rate of the laser light energy is lower than that of black, so higher output power is required to remove the colored layer 31. Therefore, the intermediate workpiece Wb (not shown) according to the third embodiment is more likely to suffer damage such as scorching of the translucent base material 20 and to leave irradiation marks 90 than the intermediate workpiece W1 according to the first embodiment. For this reason, the present invention is particularly suitable for use as a resin molded product 10B.

[0071] The laser irradiation device 50 for manufacturing the resin molded products 10, 10A, and 10B according to the first to third embodiments is a CO laser having a wavelength of 10.64 μm. ２ Although the laser is used as an example, the type and wavelength of the laser to be used can be selected depending on the materials constituting the light-transmitting substrate 20 and the light-shielding coatings 30, 30B. For example, a YAG laser, a YVO ４ A laser or the like may also be used.

[0072] 11 is a front view of a vehicle lamp 70 according to a fourth embodiment. The vehicle lamp 70 is a front combination lamp that combines a headlamp and a daytime running lamp, and is disposed on the left and right sides of the front of the vehicle. In the vehicle lamp 70, the resin molded product 10 according to the first embodiment is used as an inner lens 76 of a daytime running light 75.

[0073] The vehicle lamp 70 comprises a container-shaped lamp body 71 that opens forward, and an outer lens 72 that closes the opening of the lamp body 71. The outer lens 72 is made of a colorless, translucent resin. The lamp body 71 and the outer lens 72 define a lamp chamber. A low beam lamp unit 73 and a high beam lamp unit 74 are disposed in the lower part of the lamp chamber, and a daytime running light 75 is disposed in the upper part.

[0074] The low beam lamp unit 73 and the high beam lamp unit 74 are well-known projector-type lamp units each equipped with a light source and a projection lens, but as they are not relevant to the present invention, their description will be omitted. In addition, the periphery of the low beam lamp unit 73 and the high beam lamp unit is concealed by an extension (not shown).

[0075] 12 is a cross-sectional view taken along line XII-XII in FIG. 11, and for ease of explanation, only the light source 77, inner lens 76, and outer lens 72 of the daytime running light 75 are shown. The daytime running light 75 includes at least the light source 77 and the inner lens 76. The light source 77 is, for example, an LED (Light Emitting Diode). The inner lens 76 is the resin molded product 10 according to the first embodiment.

[0076] In the inner lens 76, the light-transmitting base material 20 is a colorless light-transmitting resin, and black paint is used as the colored paint that forms the light-blocking coating 30. The inner lens 76 has a rectangular shape when viewed from the front of the vehicle lamp 70. A laser-decorated area 40, where the light-blocking coating 30 is not formed, is formed on the surface of the inner lens 76 that faces the outer lens. In the example shown in Fig. 11, the laser-decorated area 40 is a decorative pattern that represents the letters ABC!, but the decorative pattern is not limited to the illustrated letters and may have any shape.

[0077] The area where the light-shielding coating 30 is formed functions as a light-shielding area SA, and the area where the light-shielding coating 30 is not formed functions as a light-transmitting area PA. As a result, in the vehicle lamp 70, when the light source 77 is not lit, the light-shielding area SA exhibits the color of the light-shielding coating 30, and the laser-decorated area 40 exhibits a uniform dot-like appearance. Therefore, the irradiation marks 90 in the laser-decorated area 40 are not noticeable.

[0078] On the other hand, when the light source 77 is turned on, as shown in an enlarged view in the left circle in Fig. 12, of the light La from the light source 77, the light that enters the light-blocking area SA is blocked by the light-blocking coating 30, but the light that enters the light-transmitting area PA is transmitted through the light-transmitting substrate 20 and emitted forward from the vehicle lamp 70. Therefore, when viewed from the front, the pattern of the laser-decorated area 40 shines and is highlighted, as shown by the hatched area in Fig. 11. Furthermore, since a uniform dot pattern is formed in the laser-decorated area 40 by the recesses 41, a diffusing lens effect is achieved, and the amount of light can be used effectively.

[0079] In the above description, an example was described in which the resin molded product 10 was applied to the inner lens 76, but in the present embodiment, the resin molded product 10A or 10B may be applied to the inner lens 76, and the same effect can be achieved. Also, in the present embodiment, an example was described in which the resin molded product 10 was applied to the inner lens 76 of a front combination lamp, but it goes without saying that the resin molded product 10 may also be applied to the inner lens of other vehicle lamps, such as a rear combination lamp or a side turn signal lamp.

[0080] 13 is a front view of a vehicle lamp 80 according to a fifth embodiment of the present invention. The vehicle lamp 80 is a tail and stop lamp that functions as both a tail lamp and a brake lamp, and is disposed on the left and right sides of the rear of the vehicle. In the vehicle lamp 80, the resin molded product 10 according to the first embodiment is used as an outer lens 82.

[0081] The vehicle lamp 80 has a rectangular shape when viewed from the front, a container-like lamp body that opens forward, and an outer lens 82 that has a rectangular shape that matches the lamp body 81 and closes the opening of the lamp body 81. The lamp body 81 and the outer lens 82 define a lamp chamber.

[0082] The vehicle lamp 80 includes, within a lamp chamber, at least a light source 83 and an inner lens 85. Figure 14 is a cross-sectional view taken along line XIV-XIV in Figure 13, and for the sake of convenience, only the light source 83, the inner lens 85, and the outer lens 82 are shown, and explanations of the other components are omitted as they are less relevant to the present invention.

[0083] The outer lens 82 is the resin molded product 10 according to the first embodiment. In the outer lens 82, the light-transmitting substrate 20 is a colorless light-transmitting resin, and black paint is used as the colored paint constituting the light-blocking coating 30. The light-blocking coating 30 is formed on the inner surface of the outer lens 82, i.e., the surface facing the light source 83. At least a portion of the light-blocking coating 30 is removed by laser decoration, resulting in a rectangular laser-decorated area 40 on the upper part of the outer lens 82 and a laser-decorated area 40 showing the letters ABC! on the lower part when the vehicle lamp 80 is viewed from the front. The shapes of these laser-decorated areas 40 are merely examples, and the decorative pattern shown by the laser-decorated area 40 may be any shape.

[0084] The light source 83 includes a plurality of LEDs 83a, which are controlled to emit light at a predetermined luminous intensity depending on whether the light source 83 is used as a brake lamp or a tail lamp. The inner lens 85 is made of a red transparent resin and is shaped to fit the inner surface of the outer lens.

[0085] In the vehicle lamp 80, when the light source 83 is not lit, the light-shielding area SA exhibits the color of the light-shielding coating 30. Meanwhile, the color of the inner lens is transmitted through the translucent laser-decorated area 40, allowing it to be seen. Furthermore, the laser-decorated area 40 has uniform dot-shaped depressions formed on its inner surface, giving it the appearance of having a textured interior surface due to the uniform dots. This makes it possible to achieve the effect of the resin molded product 10 in that irradiation marks 90 in the laser-decorated area 40 are less noticeable. Furthermore, by using the resin molded product 10 as an outer lens, a decorative pattern can be applied directly to the outer lens 82, providing an appearance that is integrated with the vehicle body.

[0086] On the other hand, when the light source 83 is turned on, as shown in the enlarged view in the right circle of FIG. 14 , light La from the light source 83 (LED 83a) is blocked in the light-blocking area SA where the light-blocking coating 30 is formed. Furthermore, in the laser-decorated area 40, which is the light-transmitting area PA, the light passes through the translucent substrate 20 and is irradiated forward of the vehicle lamp 80. As a result, when viewed from the front, only the laser-decorated area 40 is highlighted, as shown by the hatched area in FIG. 13 . At this time, the uniform pattern of the recesses 41 formed in the laser-decorated area 40 provides a diffusing lens effect similar to that of a grain, thereby achieving the further effect of efficiently utilizing the amount of light. Furthermore, since the uniform pattern of the recesses 41 is formed on the inner surface of the outer lens 82, the diffusing lens effect similar to that of a grain can make water fogging on the exterior of the lamp less noticeable, and this can also function as an alternative to anti-fog coating.

[0087] In the above description, an example in which the resin molded product 10 is applied to the outer lens 82 has been described, but in this embodiment, the resin molded product 10A or 10B may be applied to the outer lens 82, and the same effect can be achieved. Furthermore, in this embodiment, an example in which the resin molded product 10 is applied to the outer lens of a rear combination lamp has been described, but it goes without saying that the resin molded product 10 may also be applied to the outer lens of other vehicle lamps, such as a front combination lamp or a side turn signal lamp. In particular, the fact that it functions as an alternative to the anti-fog coating is preferable when applied to a front combination lamp.

[0088] 15 is a front view of a vehicle lamp 70A according to a sixth embodiment of the present invention. The vehicle lamp 70A is a front combination lamp that combines a headlamp, a clearance lamp, and a daytime running light, and is disposed on the left and right sides of the front of the vehicle. In the vehicle lamp 70A, the resin molded product 10 according to the first embodiment is applied as an extension 76A.

[0089] The vehicle lamp 70A includes a container-shaped lamp body 71A that opens forward, and an outer lens 72A that closes the opening of the lamp body 71. The outer lens 72A is made of a colorless, translucent resin. The lamp body 71A and the outer lens 72A define a lamp chamber. An extension 76A is disposed between the outer lens 72 and the headlamp unit 73A.

[0090] The front shape of the extension 76A corresponds to the front shape of the vehicle lamp 70A. A circular opening 74A is provided on the left side of the extension 76A for accommodating the headlamp unit 73A. A substantially triangular clearance lamp light transmitting area CPA and a narrow daytime running light transmitting area DPA extending along the outer edge of the upper part of the extension 76A are provided on the right side of the extension 76A.

[0091] The headlamp unit 73A is a projector-type headlamp unit that can switch between high beam and low beam illumination, and is not particularly relevant to the present invention, so a detailed description thereof will be omitted. A light source 77A for the daytime running lights is disposed behind the daytime running light transmission area DPA in the lamp chamber, and a light source 77B for the clearance lamps is disposed behind the clearance lamp light transmission area CPA. The light source 77A for the daytime running lights and the light source 77B for the clearance lamps are, for example, LEDs.

[0092] In the extension 76A, the light-transmitting base material 20 is a colorless light-transmitting resin, and black paint is used as the colored paint that forms the light-blocking coating 30. The clearance lamp light-transmitting area CPA and the daytime running light-transmitting area DPA form the laser decoration area 40. Meanwhile, the portion of the extension 76A other than the clearance lamp light-transmitting area CPA and the daytime running light-transmitting area DPA forms the light-blocking area SA on which the light-blocking coating 30 is formed.

[0093] As with the inner lens 76 according to the fourth embodiment, the light-blocking coating 30 is formed on the surface of the extension 76A that faces the outer lens 72A. In addition, recesses 41 are formed on the surfaces of the daytime running light transmitting area DPA and the clearance lamp light transmitting area CPA that face the outer lens, forming a uniform dot pattern.

[0094] In the vehicle lamp 70A configured in this manner, when the light sources 77A and 77B are not lit, the light-shielding area SA exhibits the color of the light-shielding coating 30, and the laser-decorated area 40 exhibits a uniform dot-like appearance. As a result, the irradiation marks 90 in the laser-decorated area 40 are not noticeable.

[0095] On the other hand, when the light source 77A is turned on, as in the fourth embodiment, of the light La from the light source 77A, the light that enters the light-shielding area SA is blocked by the light-shielding coating 30, but the light that enters the daytime running light transmission area DPA passes through the light-transmitting substrate (not shown) 20 and is emitted forward from the vehicle lamp 70A.

[0096] Furthermore, light incident on the clearance lamp light transmission area CPA from the light source 77B is transmitted through the light-transmitting substrate (not shown) 20 and emitted forward from the vehicle lamp 70A. When viewed from the front, the patterns in the laser-decorated area 40 (clearance lamp light transmission area CPA, daytime running light transmission area DPA) shine and are emphasized. Furthermore, since the uniform dot pattern is formed in the recesses 41 in the laser-decorated area 40, a diffusing lens effect is achieved, allowing the amount of light to be used effectively.

[0097] In the above description, an example in which the resin molded product 10 is applied to the extension 76A has been described, but in this embodiment, the resin molded product 10A or 10B may be applied to the extension 76A, and the same effect can be achieved. Also, in this embodiment, an example in which the resin molded product 10 is applied to the extension 76A of a front combination lamp has been described, but it goes without saying that the resin molded product 10 may also be applied to other vehicle lamps, such as a rear combination lamp or a side turn signal lamp.

[0098] Experiment Finally, with reference to Figures 16 to 18, an experimental example of a resin molded product 10B in which a workpiece Wb for manufacturing a resin molded product 10B according to the third embodiment was used and recesses 41 or 42, 43 were formed by irradiating laser light L under various laser irradiation conditions, thereby forming a uniform pattern in the laser decoration area 40B, will be described.

[0099] The workpiece Wb was made by using polycarbonate resin as the light-transmitting substrate 20, white paint as the colored layer 31, and black paint as the light-shielding layer 32.

[0100] In the comparative example, the workpiece Wb is scanned with the laser light L in the Y direction to remove the colored layer 31, and then scanned in the X direction to remove the light-shielding layer 32, as in (b-1) and (b-2) of Figure 10. This corresponds to the intermediate workpiece Wb that is produced at the end of (b-2) of Figure 10.

[0101] In Experimental Examples 1 to 5, the workpiece Wb was scanned with laser light L in the same manner as in the comparative example to remove the light-shielding coating 30B, and then scanned with laser light L under the conditions shown in Table 1 to form dot patterns in Experimental Examples 1 to 3, and lattice patterns in Experimental Examples 4 and 5. Figures 16 to 18 are micrographs of the surfaces of the manufactured resin molded products at 30x magnification, with the left column showing images taken with ring illumination and the right column showing images taken with epi-illumination. Tables 2 and 3 show the shapes of the dot patterns or lattice patterns formed on the resin molded products 10B manufactured in each Experimental Example.

[0102]

[0103]

[0104]

[0105] It can be seen that in the comparative example, the irradiation mark 90 (especially the thin grooves 91) is clearly noticeable when scanning in (b-2) of Figure 10. On the other hand, in experimental example 1, a uniform dot pattern is formed, and the irradiation mark 90 is hardly noticeable, to the extent that it is barely visible. Also, in experimental example 2, the distance between the dots is somewhat wide, so the thin grooves 91 of the irradiation mark 90 are visible, but the dots have a more impressive appearance, so the irradiation mark 90 is less noticeable. Also, in experimental example 3, a uniform dot pattern is formed, and the irradiation mark 90 is less noticeable because it has an impressive appearance. Furthermore, with epi-illumination, the thin grooves 91 of the irradiation mark 90 are visible in experimental examples 1 to 3, but the dots are formed in a direction perpendicular to the grooves 91, so the impression as a groove is weakened and it is less noticeable.

[0106] Furthermore, in Experimental Examples 4 and 5, it can be seen that the formation of a uniform grid pattern made the irradiation marks 90 almost unnoticeable. In this way, it was proven that by forming recesses that constitute a uniform pattern in the laser-decorated area, it is possible to provide a resin molded product in which the irradiation marks are inconspicuous.

[0107] This international application claims priority based on Japanese Patent Application No. 2024-097706, filed on June 17, 2024, the entire contents of which are incorporated herein by reference.

[0108] The above descriptions of specific embodiments of the present invention have been presented for purposes of illustration. They are not intended to be exhaustive or to limit the invention to the precise forms described. Numerous modifications and variations will be apparent to those skilled in the art in light of the above description.

[0109] REFERENCE SIGNS LIST 10, 10A, 10B: Resin molded product 20: Light-transmitting resin substrate 30, 30B: Light-shielding coating 31: Colored layer 32: Light-shielding layer 40, 40A, 40B: Laser-decorated area 41, 42, 43: Recess 70, 80: Vehicle lamp 72, 82: Outer lens 76, 85: Inner lens 77, 83: Light source

Claims

1. A resin molded product having a light-shielding coating formed on the surface of a light-transmitting resin substrate, the resin molded product having a laser-decorated area where the light-shielding coating is not formed, and in which recesses constituting a uniform pattern are formed.

2. The resin molded product according to claim 1, wherein the recesses form a uniformly formed dot pattern.

3. The resin molded product according to claim 1, wherein the recesses form a uniform lattice pattern.

4. The resin molded product according to claim 1, wherein the light-shielding coating comprises a colored layer and a light-shielding layer.

5. A vehicle lamp comprising the resin molded product according to any one of claims 1 to 4.

6. A vehicle lamp comprising a resin molded product according to any one of claims 1 to 4, comprising a light source, an outer lens, and an inner lens or extension arranged between the light source and the outer lens, wherein the inner lens or the extension is the resin molded product, and the light-blocking coating is arranged on the surface facing the outer lens.

7. A vehicle lamp comprising a resin molded product according to any one of claims 1 to 4, the vehicle lamp comprising a light source and an outer lens, the outer lens being the resin molded product, and the light-blocking coating being disposed on a surface facing the light source.

8. A method for manufacturing a resin molded product, comprising: (a) preparing a translucent resin substrate of a predetermined shape having a light-shielding coating formed on its surface; (b) irradiating the surface of the translucent resin substrate with laser light to remove the light-shielding coating and form a laser-decorated area; and (c) irradiating the laser light onto the laser-decorated area to modify the surface of the laser-decorated area and form recesses, thereby forming a uniform pattern.

9. The method according to claim 8, wherein in (c), the laser light is irradiated so that the uniform pattern is a dot pattern.

10. The method according to claim 8, wherein in (c), the laser light is irradiated so that the uniform pattern forms a checkerboard pattern.

11. The method according to claim 8, wherein in (c), the recesses are formed by scanning the laser light in a direction perpendicular to the scanning direction of the laser light irradiation in (b).

12. The method according to claim 8, wherein the light-shielding coating is composed of a colored layer and a light-shielding layer, and (b) comprises: (b-1) scanning the laser light in a first direction to remove the colored layer; and (b-2) scanning the laser light in a second direction perpendicular to the first direction to remove the light-shielding layer, and wherein in (c), the recess is formed by scanning the laser light in a direction perpendicular to the second direction in (b).

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