JP2013196891A - Method of manufacturing vehicle lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding method for reliably and efficiently welding and jointing a lens and a housing even when the lens has a three-dimensional design surface.SOLUTION: A transparent jig 50 has a function of applying relative pressure to a lens and a housing and a function of controlling a light path of laser beams irradiated on the welding portion of the pressured lens and the housing. The whole of one surface serves as a lens adhesion surface 51 having the same shape as the light emission surface of the lens. The other surface serves as a laser beam incident surface 52 on which the laser is made incident. The transparent jig 50 is formed to have an appropriate thickness in an appropriate portion so that a desired light guide path may be formed for the laser beams.

Description

  The present invention relates to a method for manufacturing a vehicular lamp, and more particularly to a laser welding method in which a lens and a housing constituting a vehicular lamp are laser welded.

  Conventionally, for example, Patent Document 1 discloses a specific method for welding a lens and a housing constituting a vehicular lamp by laser irradiation.

  As shown in FIG. 11, the welding method includes a lens 82 that is transparent to the laser beam and has an annular rib 81 having an annular joint surface 80 at the tip at the outer peripheral portion of the back surface, and a laser. A housing 84 having an optical absorptivity and having an annular joint surface 83 with which the annular joint surface 80 of the lens abuts is in a state where the annular joint surfaces 80 and 83 are in contact with each other over the entire circumference. Hold under pressure.

  The method for pressurizing the lens 82 and the housing 84 is, for example, by pushing the housing 84 up toward the lens 82 whose surface is in contact with the fixed transparent pressing portion 85 and annularly joining the lens 82 restrained by the transparent pressing portion 85. The annular joint surface 83 of the housing 84 pushed up to the surface 80 is abutted.

  The welding by the laser beam allows the laser beam (Ray) emitted from the galvano scan optical system to pass through the transparent pressing portion 85 and the lens 82, and the contact portion between the annular joint surfaces 80 and 83 of the lens 82 and the housing 84. Scanning and irradiating, and the corresponding contact parts are welded to each other by mutual melting with the light energy of the laser beam (Ray).

JP 2012-6046 A

  In the above-described welding method using laser irradiation, the transparent pressing portion and the lens are generally formed of a material having the same or similar refractive index. At the same time, the transparent light holding part and the laser light transmitting part, which is at least the laser light scanning area of the lens, are transparent to the upper surface of the lens so that the light guide efficiency is not lowered due to an air layer in the middle. The lens side surface (light emitting surface) of the pressing portion is held in surface contact. The transparent pressing portion is generally formed to have a uniform thickness.

  By the way, the lens has a design surface that transmits the light emitted from the light source and radiates the light to the outside. Depending on the design and design of the vehicular lamp, there is a lens having a planar shape or a three-dimensional shape. The galvano scan optical system for emitting laser light includes a method of irradiating and welding the entire annular weld region with laser light from one galvano scan optical system, and an annular weld region using a plurality of galvano scan optical systems. There is a method of irradiating and welding each divided region divided into a plurality of regions by laser light from each galvano scan optical system.

  Of these, particularly when a lens having a three-dimensional design surface and a housing are welded using a single galvano scan optical system, the light emission surface of the transparent pressing portion that is in surface contact with the laser light transmission portion of the lens In addition, the design surface of the lens reflects a three-dimensional shape as it is, and the surface (light incident surface) on the opposite galvano-scan optical system side also exhibits a three-dimensional shape that reflects the design surface of the lens as it is.

  In the case where the installed galvano scan optical system has a small elevation angle with respect to the contact surface of the light incident surface of the transparent pressing portion on the laser light transmitting portion, in other words, the galvano to the normal line on the laser light transmitting portion of the light incident surface of the transparent pressing portion. When the angle of the installation direction of the scanning optical system is large, the laser light emitted from the galvano scanning optical system and applied to the laser light transmitting portion has a large incident angle at the laser light transmitting portion, so the laser light transmitting portion Irradiation is performed with a spot area that is larger than the spot area before reaching.

  Then, the laser light that has reached the laser light transmitting portion of the light incident surface of the transparent pressing portion is guided in the transparent pressing portion and the lens while maintaining the enlarged spot area, and the mutual annular joint surfaces of the lens and the housing are connected to each other. The contact portion is reached and the contact portion is irradiated and welded.

  However, the laser light irradiated to the contact portion has a low light energy density because the spot area is enlarged, so that the welding efficiency is also lowered.

  Therefore, the present invention was devised in view of the above problems, and the object of the present invention is to reliably and efficiently weld and bond the housing to a housing even for a lens having a three-dimensional design surface. Another object of the present invention is to provide a laser welding method that can be carried out automatically.

  In order to solve the above-mentioned problems, the invention described in claim 1 of the present invention is characterized in that a tip portion of an annular rib provided on a lens made of a light-transmitting resin having transparency to laser light, and laser light A function of applying a relative pressure to the contact surface with the upper portion of the annular abutment provided in the housing made of light-absorbing resin, and the contact surface in the state where the pressure is applied Is a method for manufacturing a vehicular lamp using a transparent jig having a function of controlling the optical path of laser light to form an annular welded portion, wherein the transparent jig is The entire surface of the lens is made to have the same shape as the light emitting surface of the lens and is in close contact with the light emitting surface, and the other surface is used as the incident surface of the laser light, so that a desired light guide path is formed for the laser light. A shape with an appropriate thickness setting on the part And it is characterized in and.

  Further, the invention described in claim 2 of the present invention is that in claim 1, the laser beam is emitted from a laser scan head and the laser scan head is adhered to the entire circumference of the annular welded portion. Assuming a surface with no deflection, the transparent jig is positioned above the substantially central portion of the substantially flat portion of the assumed surface, and the transparent jig includes the laser light emitting portion and the welding portion of the laser scan head. In the direction in which the distance connecting the laser beam emitting portion of the laser scan head and the enlarged flat surface obtained by enlarging the substantially flat surface is longer in the same direction, the thickness of the upper portion in the vicinity of the welded portion is increased. Thus, a thick part is formed.

  Further, in the invention described in claim 3 of the present invention, in claim 1 or claim 2, the length of the light guide path through which the laser light of the transparent jig is guided is 5 mm or more and 15 or less. It is characterized by this.

  The invention described in claim 4 of the present invention is the transparent jig according to any one of claims 1 to 3, wherein the refractive index of the transparent jig is the same as the refractive index of the lens or the refractive index of the lens. It is characterized by being formed of a material having a refractive index close to.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the laser beam is scanned by using a single galvano scanner type laser scan head. It is what.

  The lens has a function of applying a relative pressure to the lens and the housing, and a function of controlling the optical path of the laser beam applied to the welded portion of the lens and the housing in the state where the pressure is applied. A transparent jig having a lens contact surface with the same shape as the laser beam and a laser beam incident surface on which the other surface is incident is appropriately disposed in an appropriate portion so as to form a desired light guide path for the laser beam. The shape was set with an appropriate thickness.

  As a result, the spot of the laser beam irradiated on the welded portion does not greatly differ from the spot area on the laser beam emitting portion, and the optical energy density is substantially uniform. As a result, it is possible to form a welded portion having a uniform welded state by irradiating laser light, ensuring the reliability of welding and obtaining high reliability. At the same time, the welding efficiency by laser light irradiation is improved, and the manufacturing cost can be reduced.

It is longitudinal cross-sectional explanatory drawing of a vehicle lamp. It is sectional explanatory drawing of a lens. It is sectional explanatory drawing of a housing. It is explanatory drawing of a transparent jig. It is explanatory drawing which shows the state which set the transparent jig | tool. FIG. 6 is a partial explanatory diagram of FIG. 5. It is explanatory drawing which shows the irradiation state of a laser beam. FIG. 8 is a partial explanatory diagram of FIG. 7. It is an optical path tracking figure of the laser beam concerning this embodiment. It is an optical path trace figure of the laser beam concerning a prior art example. It is explanatory drawing of a prior art example.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to FIGS. 1 to 10 (the same parts are denoted by the same reference numerals). The embodiments described below are preferable specific examples of the present invention, and thus various technically preferable limitations are given. However, the scope of the present invention particularly limits the present invention in the following description. Unless stated to the effect, the present invention is not limited to these embodiments.

  In the vehicular lamp 1, for example, as shown in FIG. 1 (a longitudinal sectional view of the vehicular lamp), a lens chamber 10 and a housing 20 form a sealed chamber 30, and a light source 40 is placed in the lamp chamber 30. Contained configuration.

  As shown in FIG. 2 (lens cross-sectional explanatory diagram), the lens 10 is a light-transmitting resin (for example, PMMA) that is transmissive to light emitted from the light source 40 and laser light used in a welding process with the housing 20 described later. (Polymethylmethacrylate) resin), polycarbonate resin, etc.), and the design surface portion 11 that transmits the emitted light from the light source 40 and irradiates it in the forward direction, and the annular edge of one surface of the design surface portion 11 It has an annular rib 12 that rises from the side and extends in a predetermined direction.

  On the other hand, the housing 20 is made of a light-absorbing resin (for example, ASA (acrylonitrile styrene acrylate) resin, etc.) having absorptivity with respect to the laser beam as shown in FIG. 21 has a light source mounting portion 22 for mounting the light source 40, and an annular support 24 is provided at the annular opening end of the opening 23.

  Then, the annular rib 12 of the lens 10 is welded to the annular support 24 of the housing 20 by laser light to form a lamp chamber 30 formed of a sealed space, and the light source mounting portion 22 of the bottom portion 21 of the housing 20 has a light source. 40 is mounted and the light source 40 is accommodated in the lamp chamber 30.

  Next, a method for welding the lens 10 and the housing 20 will be specifically described.

  First, as shown in FIG. 4 (an explanatory diagram of a transparent jig), the vehicle lamp 1 is configured such that it is transmissive to laser light and one surface (lens contact surface) 51 as a whole is a lens 10. A transparent jig 50 having the same shape as the light emitting surface 13 (see FIGS. 1 and 2) that is a surface for emitting light from the light source 40 to the outside of the lamp is sometimes prepared. The other surface (laser light incident surface) 52 of the transparent jig 50 has a shape different from that of the lens contact surface 51. That is, the entire thickness of the transparent jig 50 is not uniform, and an appropriate thickness is set at an appropriate portion so as to form a desired light guide for the laser light.

  The transparent jig 50 is formed of a material having a refractive index that is the same as the refractive index of the lens 10 or approximate to the refractive index of the lens 10.

Next, FIG. 5 (an explanatory diagram showing a state where a transparent jig is set) and FIG. 6 (a partial explanatory diagram of FIG. 5)
As shown in FIG. 2, the lens 10 is held by the transparent jig 50 in a state where the light exit surface 13 is in close contact with the lens contact surface 51 of the transparent jig 50 in a fixed state. At the same time, the lens 10 and the housing 20 are disposed to face each other, the tip surface (adhesion surface) 14 of the rib 12 of the lens 10 and the upper surface (welding surface) 25 of the abutment portion 24 of the housing 20 are opposed to each other, 20 is pressed toward the lens 10 to hold the welding surfaces 14 and 25 in a relative pressed state.

  Next, as shown in FIG. 7 (an explanatory diagram showing the irradiation state of laser light) and FIG. 8 (a partial explanatory diagram of FIG. 7), one galvano scanner type laser disposed above the transparent jig 50 The laser beam L is radiated from the scan head 55 in an annular shape toward the vicinity of the transparent jig 50 above the rib 12 of the lens 10. This laser irradiation is repeatedly scanned along the annular rib 12 a plurality of times.

  Then, the laser beam L emitted from the laser scanning head 55 toward the upper vicinity of the rib 12 of the lens 10 of the transparent jig 50 is the design surface portion 11 and the rib of the lens 10 made of a light transmitting resin that transmits the laser beam L. 12, is emitted from the front end surface 14 of the rib 12, and the emitted light reaches and irradiates the upper surface 25 of the abutment portion 24 of the housing 20 made of light-absorbing resin, which is in contact with the front end surface 14. .

  Then, the portion of the upper surface 25 of the abutment portion 24 of the housing 20 irradiated with the laser light L in the vicinity of the region where the tip surface 14 of the rib 12 comes into contact absorbs the energy of the laser light L and generates heat and melts. . The volume of the melted portion increases due to thermal expansion, and the volume increase swells toward the front end surface 14 of the rib 12 of the lens 10 that is in face-to-face contact.

  At this time, the front end surface 14 of the rib 12 of the lens 10 and the upper surface 25 of the abutment portion 24 of the housing 20 are in a pressed state. For this reason, the melted portion swelled toward the front end surface 14 of the rib 12 of the lens 10 transmits the thermal expansion force of the melted portion as it is to the front end surface 14 of the rib 12 of the lens 10 and receives the thermal expansion force. The heat of the melting part is transmitted to the vicinity of the front end surface 14 and the part is heated and melted to form the melting part. As a result, the melted portion of the abutment portion 24 of the housing 20 and the melted portion of the rib 12 of the lens 10 are fused and welded.

  Here, the method for welding the lens 10 and the housing 20 will be described in more detail. In this description, in particular, the conventional welding method using the transparent jig 60 having a uniform overall thickness and the welding method of the present invention (embodiment) using the transparent jig 50 having a non-uniform overall thickness. Verify the difference.

  As described above, the welding method of the present embodiment is a three-dimensional structure of the radiation of the laser beam L and the tip surface (adhesion surface) 14 of the rib 12 of the lens 10 and the upper surface (weld surface) 25 of the abutment 24 of the housing 20. The annular contact surface (welded portion) 28 having a typical three-dimensional shape is scanned by using a single galvano scanner type laser scan head 55, and the laser scan head 55 is connected to the annular welded portion 28. It is installed above (see FIGS. 7 and 8).

  The laser scan head 55 is assumed to be a non-deflection surface attached around the entire circumference of the annular welded portion 28 having a three-dimensional three-dimensional shape. The transparent jig 50 is positioned substantially above the center portion of the laser scanning head 55 so that the distance between the laser light emitting portion of the laser scan head 55 and the welded portion 28 is substantially flat with the laser light emitting portion of the laser scan head 55 in the same direction. In the direction longer than the distance connecting the enlarged flat surfaces obtained by enlarging the surface, the thick portion 53 is formed by increasing the thickness of the upper portion in the vicinity of the welded portion 28 of the transparent jig 50 (see FIG. 7). Yes.

  The distance connecting the laser beam emitting portion of the laser scan head 55 and the welded portion 28 is larger than the distance connecting the laser beam emitting portion of the laser scan head 55 and the enlarged flat surface obtained by enlarging the substantially flat surface in the same direction. The welded portion 28 located in the longer direction means a portion that goes around the side of the vehicle when the vehicular lamp is mounted on the vehicle.

  Therefore, as shown in FIG. 9 (laser beam optical path tracking diagram), the laser beam L1 having a spot diameter φD emitted from a laser scan head (not shown) and applied to the thick portion 53 of the transparent jig 50 is Then, the light beam is refracted into the transparent jig 50 from the laser light incident surface 52 of the transparent jig 50 at an incident angle α, and travels toward the welded portion 28.

  At this time, the laser beam L1 is guided along a distance M in the transparent jig 50 and is guided in an elliptical shape with a long axis A1 projected onto the laser beam incident surface 52 at an incident angle α. Further, the design surface portion 11 of the lens 10 and the rib 12 of the lens 10 are guided to irradiate the welded portion 28.

  At this time, the welded portion 28 is inclined with respect to the light guide direction of the laser light L1. Therefore, the laser beam L1 guided in an elliptical shape with the long axis A1 is irradiated as a long axis A2 longer than A1.

  The length of the light guide path through which the laser beam L1 of the transparent jig 50 is guided is preferably 5 mm or more and 15 or less in order to ensure the strength of the transparent jig 50 and at the same time reduce the light guide loss as much as possible. .

  On the other hand, the conventional welding method, like the welding method of the present embodiment, emits laser light, and the tip surface (adhesion surface) 14 of the rib 12 of the lens 10 and the upper surface (welding) of the abutment portion 24 of the housing 20. Scanning) to the annular contact surface (welded portion) 28 having a three-dimensional three-dimensional shape is performed by using one galvano scanner type laser scan head 55, and the laser scan head 55 is annular. Is installed above the welding portion 28 (see FIGS. 7 and 8).

  Unlike the transparent jig 50 of the above-described embodiment, the transparent jig 60 has a uniform overall thickness.

  Therefore, as shown in FIG. 10 (optical path tracking diagram of laser light), a laser having a spot diameter φD emitted from a laser scan head (not shown) and applied to the transparent jig 60 in the same direction as the present embodiment. The light L2 is refracted and incident on the transparent jig 60 from the laser light incident surface 62 of the transparent jig 60 at an incident angle β and travels toward the welded portion 28.

  At this time, the laser beam L2 is guided along a distance N in the transparent jig 60 and is guided in an elliptical shape with a major axis B1 projected onto the laser beam incident surface 62 at an incident angle β. Further, the design surface portion 11 of the lens 10 and the rib 12 of the lens 10 are guided to irradiate the welded portion 28.

  At this time, the welded portion 28 is inclined with respect to the light guide direction of the laser light L2. Therefore, the laser beam L2 guided in an elliptical shape with the long axis B1 is irradiated as a long axis B2 longer than B1.

  Therefore, when comparing the above-described welding method of the present embodiment and the conventional welding method, the conventional welding method uses a transparent jig 60 in which the entire thickness is uniformly formed. Thus, a transparent jig 50 having an appropriate thickness set at an appropriate portion so as to form a desired light guide is used.

  Then, the distance connecting the laser beam emitting part and the welded part of the laser scan head is directed to the welded part located at a position longer than the distance connecting the laser beam emitting part of the laser scan head and the enlarged flat surface in the same direction. The emitted laser light is projected at an incident angle α on the laser light incident surface 52 of the transparent jig 50 in the present embodiment, and incident on the laser light incident surface 62 of the transparent jig 60 in the conventional example. Projection is performed at an incident angle β larger than the angle α.

  Therefore, the laser beam L2 projected onto the laser beam incident surface 62 of the transparent jig 60 and the laser beam L1 projected onto the laser beam incident surface 52 of the transparent jig 50 both have an elliptical shape. Since the incident angle β is larger than the incident angle α, the laser beam L2 projected onto the laser beam incident surface 62 of the transparent jig 60 has an elliptical shape with a long major axis.

  Therefore, the laser beam L1 guided in the transparent jig 50 has an elliptical shape with a long axis A1, whereas the laser beam L2 guided in the transparent jig 60 has a long axis B1 longer than the long axis A1. It becomes an elliptical shape.

  As a result, the laser beam L2 applied to the welded portion 28 has an elliptical shape with a long axis longer than that of the laser beam 1. That is, the spot of the laser beam L2 irradiated to the welded portion 28 has a larger area than the spot of the laser beam L1, so that the light energy density is small and the welding efficiency is low.

  At the same time, as shown in FIG. 10 when the conventional transparent jig 60 is used, the spot shape of the ellipse of the laser beam L2 irradiated to the welded portion 28 has a length on both sides of the short axis C. In other words, the areas are different, and the light energy densities are different. As a result, the welded state of the welded portion 28 by the laser beam L2 becomes non-uniform, and the reliability of welding is impaired, so that reliability cannot be ensured.

  On the other hand, in this embodiment, as shown in FIG. 9, by using a transparent jig 50 having an appropriate thickness set at an appropriate portion so as to form a desired light guide for the laser light L1. The spot of the laser beam L1 applied to the welded portion 28 is not greatly different from the spot area when emitted from the laser scan head, and the lengths on both sides of the short axis E, in other words, the areas are almost the same. Thus, the light energy density becomes uniform. As a result, it is possible to form the welded portion 28 in a uniform welded state by irradiation with the laser beam L1, ensuring the reliability of welding and obtaining high reliability. At the same time, the welding efficiency by irradiation with the laser beam L1 is improved, and the manufacturing cost can be reduced.

DESCRIPTION OF SYMBOLS 1 ... Vehicle lamp 10 ... Lens 11 ... Design surface part 12 ... Rib 13 ... Light-emitting surface 14 ... Tip surface (welding surface)
DESCRIPTION OF SYMBOLS 20 ... Housing 21 ... Bottom part 22 ... Light source mounting part 23 ... Opening 24 ... Abutment part 25 ... Upper surface (welding surface)
28 ... Contact surface (welded part)
DESCRIPTION OF SYMBOLS 30 ... Lamp chamber 40 ... Light source 50 ... Transparent jig | tool 51 ... Lens contact surface 52 ... Laser beam incident surface 53 ... Thick part 55 ... Laser scan head 60 ... Transparent jig 62 ... Laser beam incident surface

Claims (5)

A tip end portion of an annular rib provided on a lens made of a light-transmitting resin having transparency to laser light, and an annular abutment provided on a housing made of a light-absorbing resin having absorbency to laser light A function of applying a relative pressure to the contact surface with the upper portion of the portion, and a function of performing an optical path control of a laser beam that forms an annular weld portion by thermally welding the contact surface in a state where the pressure is applied. A method for manufacturing a vehicular lamp related to a laser welding process using a transparent jig having,
The transparent jig has one surface entirely in the same shape as the light emitting surface of the lens and is in close contact with the light emitting surface, and the other surface is used as a laser light incident surface. A method for manufacturing a vehicular lamp, characterized in that an appropriate thickness is set in an appropriate part so as to form a lamp. The laser light is emitted from a laser scan head, and the laser scan head is assumed to be a non-deflection surface attached around the entire circumference of the annular welded portion, and is an approximately flat portion of the assumed surface. Located approximately above the center of the flat surface,
The distance between the laser beam emitting portion of the laser scan head and the welded portion is a distance between the laser beam emitting portion of the laser scan head and an enlarged flat surface obtained by enlarging the substantially flat surface in the same direction. The method for manufacturing a vehicular lamp according to claim 1, wherein in the longer direction, the thick part is formed by increasing the thickness of the upper part in the vicinity of the welded part.   The method for manufacturing a vehicular lamp according to claim 1 or 2, wherein a length of a light guide path through which the laser beam of the transparent jig is guided is 5 mm or more and 15 or less.   4. The transparent jig is formed of a material having a refractive index that is the same as or similar to the refractive index of the lens. A method for manufacturing a vehicular lamp according to claim 1.   The said laser beam is scanned using the laser scan head of one galvano scanner system, The manufacturing method of the vehicle lamp in any one of Claims 1-4 characterized by the above-mentioned.

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