Patent Description:
Conventionally, in the case where a contact portion between a front surface cover and a lamp body of a lighting fixture of a vehicle is laser welded, there has been known a mode in which a visible-light blocking layer that transmits laser light and absorbs visible light is disposed in the laser-welded portion between the full surface cover and the lamp body, so as to prevent cloudiness due to bubbles appearing in the laser-welded portion from being visible through the laser-welded portion (see <CIT>).

The full surface cover (hereinafter also referred to as an outer lens) is a member that covers an opening in the front side of the lamp body (hereinafter also referred to as a housing) in which a light source is disposed, to seal the opening. The full surface cover is made of a material that transmits visible light so that light from the light source can basically be emitted forward.

In some cases, the outer lens is colored in red or orange depending on the type of the lamp, such as stop lamp, turn lamp, etc. Since it is necessary to transmit visible light from such a lamp, even the colored portions are at least translucent. Therefore, even if there are some scratches on the surface, the scratches are less likely to stand out.

In the case where a region (hereinafter also referred to as a dressed region) other than the region that emits light and serves as a lamp is provided as a design of the outer lens, the dressed region must be clearly distinguished from the lamp region that emits light and serves as a lamp (hereinafter also referred to as a light emitting region).

If the dressed region is made of a material that does not transmit visible light, the light from the light emitting region does not pass through the dressed region. Therefore, the dressed region can be clearly distinguished from the light emitting region.

However, in such a case, there is a problem in that a scratch on the surface is easily noticeable due to light reflected at the scratch.

Therefore, we have appreciated that it would be desirable to provide an outer lens of a lighting fixture for a vehicle in which a scratch is not easily noticeable even in a dressed region, a lighting fixture for a vehicle including the outer lens, and a method for producing the lighting fixture for a vehicle.

<CIT> discloses a welding technique for a vehicular lamp. A weld surface of a weld portion provided on a translucent cover is pressed against a surface to be welded that is formed on a lamp housing. The translucent cover and the lamp housing are welded by a laser light irradiated from a welding head on the weld portion. The welding head is moved, during the method of making the lamp, along the weld surface, and the angle of the welding head while moving is varied depending on the orientation of the weld surface so that the orientation angle variation amount of the weld surface is set to be equal to or less than <NUM> deg/mm for areas which are adjacent in the moving direction of the welding head.

<CIT> discusses a technique for providing a laser deposition structure capable of depositing, with laser light, a member having a low translucent area such as a color area for preventing a deposited surface part that is laser deposited from being exposed. A laser deposited structure (a lamp housing) is discussed in which a first resin member (a lamp body) and a second transparent resin member (a front cover) having integrally a low translucent area (color area) with a partial low light transmittance rate are laser deposited. A deposited surface part having the first resin member and the second resin member deposited to each other is arranged at a rear part of the low translucent area. The second resin member has integrally deposited legs for guiding laser light irradiated against an area other than the low translucent area to the deposited surface part.

<CIT>, aims to provide a vehicular lighting fixture capable of obtaining a firm jointing of a lamp lens and a lamp housing. A range W1 of a laser welded part is within a range W2 of of a joint face <NUM> of a lamp lens <NUM>. That is, a part where a laser light L is irradiated is within a range of a tip face <NUM> of a seal leg part <NUM> as a joint face. Therefore, the laser light L goes straight and transmits the seal leg part <NUM>, and directly irradiates on joint face <NUM>. As a result, an irradiation energy of the laser light on the joint face is never uneven as the laser light is partially amplified by refraction, reflection or the like at a slanted face, even if a side face of the seal leg part <NUM> is slanted due to the eject angle. Therefore, the irradiation energy of the laser light on the joint faces <NUM>, <NUM>, and the joint faces <NUM>, <NUM> are laser welded nearly equally, so that a firm jointing is obtained.

<CIT> also aims to provide a vehicular lighting fixture capable of obtaining a firm jointing of a lamp lens and a lamp housing. A joint part of a lamp lens is composed of a resin member having a light-transmitting property, so that a laser light L passes through the joint part, and directly irradiates joint faces of a joint convex part and a joint concave part. With this, an irradiation energy of the laser light L is equal on the joint faces of the joint convex part and the joint concave part. As a result, the joint faces <NUM>, <NUM> of the joint convex part <NUM> and the joint concave part <NUM> are laser welded nearly equally, so that a firm jointing is obtained.

<CIT> provides a technique to obtain a firm jointing, to improve the appearance, simplify the manufacturing equipment and process. A laser welding is carried out on an inner side face of a seal leg part, so that there are no concave gaps formed on joint faces. As a result, a firm jointing is obtained since an adhesiveness of the joint faces is improved. Also, since the laser welding is made on a jointing face of an inner side face of the seal leg part and an outer side face of the jointing part, an appearance is improved as the laser-welded part looks just like a line and is hardly conspicuous. Further, since the jointing faces are tightly adhered to each other by a slanting of the inner side face of the seal leg part and the outer side face of the jointing part, there is no need to manufacture equipment such as pressurizing means for adhering the jointing faces. Moreover, the manufacturing process becomes simple since the pressurizing means is not required.

According to an aspect of the disclosure, an outer lens that is used for a lighting fixture for a vehicle includes a first region formed of a first material, the first material (<NUM>) is a material transmitting light from a first light source of a semiconductor type having an emission wavelength in a visible light range; and a second region formed of a material that is colored, and that does not emit light from the first light source, the second region being adjacent to the first region and including a region other than a region in contact with a housing. The second material includes a first wavelength range in which a light transmittance is equal to or less than a first transmittance; a second wavelength range on a longer wavelength side of the first wavelength range, with the light transmittance being equal to or more than a second transmittance in the second wavelength range; and a third wavelength range between the first wavelength range and the second wavelength range. The first wavelength range is a wavelength range including a visible light at an S wavelength at least established within a visible light range or a shorter wavelength, the second wavelength range includes a wavelength range from an M wavelength at least established within a visible light range on a longer wavelength side of the S wavelength to an L wavelength longer than the M wavelength. The first transmittance is set to a low transmittance that suppresses transmission of light in the first wavelength range. The second transmittance is set to a high transmittance that allows transmission of light in the second wavelength range. The third wavelength range is established to increase transmittance from the S wavelength to the M wavelength so that a portion of the visible light penetrates inside of the second region (<NUM>) to become light reflected toward the surface of the second region (<NUM>). The transmittance is adjusted by a coloring agent contained in the second material. The first wavelength range includes the emission wavelength to suppress the transmission of light from the first light source.

According to this aspect, the first transmittance and the second transmittance are preferably transmittances measured when the second material is formed into a plate having a thickness of <NUM>. The first transmittance is preferably <NUM>% or less and the second transmittance is <NUM>% or more.

In this aspect, the second wavelength range is preferably established to be a range including at least a wavelength of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> or <NUM>,.

In this aspect, the S wavelength is preferably a wavelength of <NUM> or more but less than <NUM>, and the emission wavelength is preferably within a wavelength range of <NUM> or more but less than <NUM>.

In this aspect, the outer lens preferably is free of a rib structure for blocking light from the first light source in the second region.

In this aspect, the first material and the second material each preferably include a thermoplastic resin as a base material, and the second material is preferably a material containing a dye as a coloring agent in the base material.

According to another aspect, a method of producing a lighting fixture for a vehicle includes preparing a lamp body, including a housing, that opens in a light irradiation direction and accommodates a first light source of a semiconductor type, having an emission wavelength in a visible light range; preparing an outer lens that covers an opening of the housing; and laser welding an area where the outer lens and the housing are in contact with each other, wherein the outer lens is the outer lens according to the above-described aspect, and a laser beam having a wavelength within the second wavelength range is used during the laser welding.

According to another aspect, a lighting fixture for a vehicle includes a lamp body, including a housing, that opens in a light irradiation direction and accommodates a first light source of a semiconductor type, having an emission wavelength in a visible light range as well as an outer lens that covers an opening of the housing, and the outer lens according to the first aspect.

The disclosure provides an outer lens of a lighting fixture for a vehicle in which a scratch is not easily noticeable even in a dressed region, a lighting fixture for a vehicle including the outer lens, and a method for producing the lighting fixture for a vehicle.

Embodiments will now be described with reference to the accompanying drawings.

Note that the same numbers or reference signs denote the same elements throughout the description of the embodiments.

In the embodiments and drawings, the terms "front", "rear", "top", "bottom", "left", and "right" refer to directions as seen from the driver of the vehicle, unless otherwise specified.

Note that the terms "top" and "bottom" also respectively refer to the "top" and the "bottom" in the vertical direction, and the terms "left" and "right" also respectively refer to the "left" and "right" in the horizontal direction.

<FIG> is a perspective view of a lighting fixture <NUM> for a vehicle of the present embodiment.

<FIG> is a perspective view of a lamp body <NUM> of the present embodiment. <FIG> is a view on arrow A in <FIG>.

<FIG> is a perspective view of the front side of an outer lens <NUM> of the present embodiment. <FIG> is a perspective view of the rear side of the outer lens <NUM> of the present embodiment.

Note that the lighting fixture <NUM> for a vehicle of the present embodiment is a rear combination lamp provided on each of the left rear side and the right rear side of the vehicle, but it is not limited thereto.

The lighting fixture <NUM> for a vehicle illustrated in <FIG> includes a lamp body <NUM> illustrated in <FIG> and <FIG>, and an outer lens <NUM> illustrated in <FIG> and <FIG>.

As illustrated in <FIG> and <FIG>, the lamp body <NUM> includes a housing <NUM> opening in the light irradiation direction (in this example, the side of the vehicle (left or right side) and the rear side of the vehicle), an inner panel <NUM> fixed to the housing <NUM>, and a cable CA that is led out from the rear side of the housing <NUM> and includes a connector CN for supplying electric power.

Note that the inner panel <NUM> of the present embodiment is entirely painted or vapor-deposited in silver.

As illustrated in <FIG>, the inner panel <NUM> has a light irradiation window 12A for a side marker that emits light toward the side (left or right side) of the vehicle. An inner lens IL1 is disposed on the front surface side of a region of the inner panel <NUM> including the light irradiation window 12A.

Note that the front or back surface of the inner lens IL1 has a grid pattern or embossing, such as grains, and thus, the back side is not readily visible.

The housing <NUM> accommodates a light source from which light so that light is emitted from the light irradiation window 12A of the inner panel <NUM>.

Note that, in the drawing, the light source for the side marker is hidden behind the inner panel <NUM>.

As illustrated in <FIG>, the inner panel <NUM> has an opening 12B in which a light guide member <NUM> is disposed. The light for the tail lamp is emitted from the light guide member <NUM> disposed in the opening <NUM>.

The housing <NUM> accommodates a light source so that light is incident on a light incident end (not illustrated) of the light guide member <NUM>.

Note that, in the drawing, the light source for the tail lamp is also hidden behind the inner panel <NUM>.

As illustrated in <FIG>, the inner panel <NUM> has a light irradiation window 12C for a stop lamp that emits light toward the rear of the vehicle. An inner lens IL2 is so disposed to cover the light irradiation window 12C.

The housing <NUM> accommodates a light source so that light is emitted from the light irradiation window 12C in the inner panel <NUM>.

Note that the front or back surface of the inner lens IL2 has a grid pattern or embossing, such as grains, and thus, the light source for the stop lamp is not visible.

In the present embodiment, the light source for the side marker, the light source for the tail lamp, and the light source for the stop lamp are each a red LED light source of a semiconductor type (having an emission center wavelength of approximately <NUM>) serving as a first light source having an emission wavelength within the range of <NUM> to <NUM>. Alternatively, each light source may be an LD light source (a laser diode light source) or the like.

Note that the mode of the housing 11accommodating the first light source is not particularly limited. The first light source is not limited to one fixed to the housing <NUM>. Alternatively, the first light source may be one that is fixed to the inner panel <NUM>, and the inner panel <NUM> to which the first light source is fixed may be fixed to the housing <NUM>.

As illustrated in <FIG>, the inner panel <NUM> has a recess 12D for a turn lamp that emits light toward the rear side of the vehicle. A light emitting section of a light bulb <NUM> that emits orange light is disposed in the recess 12D.

As illustrated in <FIG>, the outer lens <NUM> is a member fixed to the housing <NUM> so as to cover the opening of the housing <NUM> (see <FIG> and <FIG>) opening in the light irradiation direction (in this example, toward a side of the vehicle (left or right side) and the rear side of the vehicle).

As illustrated in <FIG>, the outer lens <NUM> includes a first region <NUM> corresponding to the side marker, the tail lamp, and the stop lamp that emit light from the first light sources, a second region <NUM> provided adjacent to the first region <NUM> that is a dressed region for design and does not emit light, and a third region <NUM> that is separated from the second region <NUM> by the first region <NUM> and corresponds to the turn lamp that emits light from the light bulb <NUM> (see <FIG>).

The base material of the first region <NUM>, the second region <NUM>, and the third region <NUM> are acrylic resin.

The base material of the first region <NUM> is a first material containing a red dye as a coloring agent. The first region <NUM> is a translucent region colored red that sufficiently transmits light from the first light source. The base material of the third region <NUM> contains no dye, and thus the third region <NUM> is a colorless and transparent region made of the base material or a third material.

The base material of the second region <NUM> is a second material containing dyes of multiple colors as coloring agents to colored the second material black. The second region <NUM> is the region colored black. The outer lens <NUM> of the present embodiment integrates the materials (the first material, the second material, and the third material) through multicolor molding.

A dye used as a coloring agent for coloring such a portion has higher compatibility with the base material than a pigment used as a coloring agent. Therefore, when a dye is used as a coloring agent, the color is enhanced, and the weather resistance of the exterior can be improved with almost no deterioration of the weather resistance of the exterior due to coloring.

Note that, in the present embodiment, an acrylic resin is used as the base resin. However, the base resin is not limited thereto. Alternatively, the base resin may be any resin that is a thermoplastic resin that does not hinder welding as described below, beside acrylic resin.

However, in consideration of weldability, mechanical strength, weather resistance, etc., it is preferable to use acrylic resin as the base resin.

The second material constituting the second region <NUM> will now be described in more detail.

<FIG> is a graph showing the measured results of transmittance X of when a plate material having a thickness of <NUM> is used as the second material.

Note that the transmittance X is calculated as "transmittance X=(transmitted light intensity X2/irradiated light intensity X1)×<NUM>[%], where irradiated light intensity X1 is the intensity of the light incident on the plate material for measurement and the transmitted light intensity X2 is the intensity of the light transmitted through the plate material. In <FIG>, the horizontal axis represents the wavelength [nm] of light, and the vertical axis represents the transmittance X[%] for light of each wavelength.

The transmittance of the second material is adjusted by incorporating multiple dyes that absorb light on the shorter wavelength side of the S wavelength but hardly absorb light on the longer wavelength side of the S wavelength, as described below.

Typically, visible light that can be seen by the human eye is said to be in the wavelength range of <NUM> to <NUM> (hereinafter referred to as the visible light range). As illustrated in <FIG>, the second material has a first wavelength range Y1 set to a first transmittance or lower. The first wavelength range Y1 is a wavelength range including visible light on the shorter wavelength side of the S wavelength, which is approximately <NUM> and established in the visible light range. The first transmittance is a low transmittance that suppresses the transmission of light in the first wavelength range Y1.

Specifically, the first transmittance is preferably <NUM>% or less, more preferably <NUM>% or less, further preferably <NUM>% or less. In the present embodiment, the first transmittance is approximately <NUM>%.

By reducing the first transmittance in this way, it is possible to suppress transmission of light in the first wavelength range Y1 even if the thickness of the outer lens <NUM> is reduced to reduce the weight and material cost.

As described above, the emission wavelength of the first light source is within the range of <NUM> to <NUM>. Thus, the first wavelength range Y1 includes the emission wavelength of the first light source, and the second region <NUM> made of the second material suppresses the transmission of light from the first light source.

Therefore, as illustrated in <FIG>, even when the outer lens <NUM> has a simple configuration without a rib structure that can block the light from the first light source from entering the second region <NUM> at the boundary between the first region <NUM> and the second region <NUM>, the second region <NUM> does not emit the light from the first light source.

Note that, as illustrated in <FIG>, the lamp body <NUM> may have no rib structure that can block light from the first light source from entering the second region <NUM> (see <FIG>).

Since the second region <NUM> is formed of the second material, as described above, the light from the first region <NUM> (lamp region) is not emitted through the second region <NUM> (dressed region), without a complicated structure, such as a rib structure, for blocking light, the second region <NUM> can be clearly distinguished from the lamp region.

Note that, when light broadly includes all wavelengths in the visible light range, such as that from a bulb, the second region <NUM> cannot be clearly distinguished from the first region <NUM> (lamp region) because even when the transmittance of the light on the shorter wavelength side of the S wavelength (approximately <NUM> in this example) is lowered in the visible light range, the light on the longer wavelength side of the S wavelength transmits the second region <NUM>. Therefore, it is preferable that the first light source be a light source of a semiconductor type that has an emission wavelength in a specific range within the visible light range (for example, a specific range in the visible light range of <NUM> or lower).

As illustrated in <FIG>, the second material has a second wavelength range Y2 and a third wavelength range Y3. The second wavelength range Y2 is disposed on the longer wavelength side of the first wavelength range Y1 and has light transmittance higher than or equal to a second transmittance. The third wavelength range Y3 is disposed between the first wavelength range Y1 and the second wavelength range Y2.

Specifically, the second material includes a high-transmittance second wavelength range Y2 in which the second transmittance is <NUM>% or higher. The second wavelength range Y2 has a wavelength range established on the longer wavelength side of the S wavelength or <NUM> in the visible light range, between an M wavelength or <NUM> and an L wavelength or <NUM> on the longer wavelength side of the M wavelength.

Furthermore, the second material includes a second wavelength range Y2 in which the second transmittance is <NUM>% or higher. The second wavelength range Y2 has a wavelength range established on the longer wavelength side of the S wavelength or <NUM> in the visible light range, between an M wavelength or <NUM> and an L wavelength or <NUM> on the longer wavelength side of the M wavelength.

Since the second material has a transmittance of almost <NUM>% or more in the wavelength range of <NUM> to <NUM>, the second material includes a second wavelength range Y2 in which the second transmittance is almost <NUM>% or higher. The second wavelength range Y2 has a wavelength range established on the longer wavelength side of the S wavelength or <NUM> in the visible light range, between an M wavelength or <NUM> and an L wavelength or <NUM> on the longer wavelength side of the M wavelength.

Although the reason will be described below, the second wavelength range Y2 is preferably established as a range including at least one of the wavelengths of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. When the second transmittance of the second material is <NUM>% or more, <NUM>% or more, or almost <NUM>% or more, the second wavelength range Y2 can be established as a range including at least one wavelength of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

As illustrated in <FIG>, in the third wavelength range Y3, the transmittance increases from the S wavelength or <NUM> to the M wavelength (for example, the M wavelength is <NUM> when the second transmittance is <NUM>%, <NUM> when the second transmittance is <NUM>%, and <NUM> when the second transmittance is almost <NUM>% or more).

Since the third wavelength range Y3 is on the longer wavelength side of the visible light range, the third wavelength range Y3 can transmit a portion of the visible light on the longer wavelength side.

Therefore, in the second region <NUM> formed in the second material, not all visible light is reflected at the surface, and a portion of the visible light penetrates inside. The visible light that penetrates inside is reflected toward the surface due to scattering, or the like.

For this reason, even if there is a scratch on the surface, the light reflected at the scratch is visually recognized while the light is mixed with light reflected from the inside of the second region <NUM>. Therefore, the light reflected at the surface of the scratch is less noticeable, and thus, the scratch itself is less noticeable.

Since the visible light in the visible light range on the longer wavelength side penetrates inside the second region <NUM>, the reflection at the surface of the second region <NUM> is reduced and the white light feeling of the surface is suppressed. As a result, the second region <NUM> appears to be a deep black color and can achieve an imposing design.

When the emission wavelength of the first light source is within the range of <NUM> to <NUM> as in the present embodiment, it is preferable that the above-mentioned S wavelength be <NUM> or more to prevent transmission of light to the second region <NUM> from the first light source.

As described above, to transmit a portion of the light on the longer wavelength side of the visible light range and make a scratch on the surface of the second region <NUM> less noticeable, it is preferred that the S wavelength be less than <NUM>, and the third wavelength range Y3, which is a wavelength range between the S wavelength and the M wavelength, be a wavelength range including a wavelength range in the visible light range of <NUM> or more.

Note that the third wavelength range Y3 is more preferably includes the wavelength range in the visible light range of <NUM> or more, further preferably the wavelength range in the visible light range of <NUM> or more.

Carbon black is often used for black coloring. Carbon black does not transmit the wavelength, such as <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, or <NUM>, of the laser welder used in such coloring. Therefore, when the second region <NUM> is to be colored with carbon black or the like, and the contact region between the second region <NUM> and the housing <NUM> is to be laser-welded, the surface of the second region <NUM> melts first, and the contact region cannot be welded together. For this reason, another welding method should be used.

More specifically, with reference to <FIG>, which is a diagram for describing laser welding of the outer lens <NUM> and the housing <NUM>, a contact region <NUM> of the outer lens <NUM> illustrated in <FIG> and a contact region <NUM> of the housing <NUM> illustrated in <FIG> and <FIG> disposed in contact with each other are irradiated with a laser beam LB for welding from the outer lens <NUM> side. In the case where carbon black is used for coloring, the laser beam LB does not reach a contact surface <NUM>, as illustrated in <FIG>, and the surface of the outer lens <NUM> melts.

In the present embodiment, the second region <NUM>, including the region in contact with the housing <NUM> and other regions, formed of the second material is transparent to the wavelength used in the laser welders, and thus, the laser beam LB is hardly absorbed by the second material, and the contact surface <NUM> with the housing <NUM> can be irradiated with the laser beam LB, as illustrated in <FIG>. Therefore, the surface of the housing <NUM> can be heated to achieve satisfactory welding.

The first region <NUM> and the third region <NUM> have substantially the same transmittance as the second region <NUM> for the laser beam LB used by the laser welder. Therefore, it is possible to weld the portions of the first region <NUM>, the second region <NUM>, and the third region <NUM> that come into contact with the housing <NUM> without changing the conditions of laser intensity during laser welding.

Although specific embodiments have been described above, the present invention is not limited to the above embodiments.

For example, a case in which the emission wavelength of the first light source is within the range of <NUM> to <NUM> has been described in the above embodiment. Alternatively, the light source may have an emission wavelength on the shorter wavelength side.

Even in such a case, the S wavelength should be set to a wavelength in the visible light range on the longer wavelength side of the emission wavelength.

Claim 1:
An outer lens (<NUM>) that is used for a lighting fixture for a vehicle, the outer lens (<NUM>) comprising:
a first region (<NUM>) formed of a first material, the first material (<NUM>) is a material transmitting light from a first light source of a semiconductor type having an emission wavelength in a visible light range; and
a second region (<NUM>) formed of a second material that is colored, and that does not emit light from the first light source, the second region being adjacent to the first region and including a region other than a region in contact with a housing (<NUM>), wherein
the second material (<NUM>) includes:
a first wavelength range (Y1), in which a light transmittance is equal to or less than a first transmittance;
a second wavelength range (Y2) on a longer wavelength side of the first wavelength range (Y1), with the light transmittance being equal to or more than a second transmittance in the second wavelength range (Y2); and
a third wavelength range (Y3) between the first wavelength range (Y1) and the second wavelength range (Y2),
the first wavelength range (Y1) is a wavelength range including a visible light at an S wavelength at least established within a visible light range or a shorter wavelength,
the second wavelength range (Y2) includes a wavelength range from an M wavelength at least established within the visible light range on a longer wavelength side of the S wavelength to an L wavelength longer than the M wavelength,
the first transmittance is set to a low transmittance that suppresses transmission of light in the first wavelength range (Y1),
the second transmittance is set to a high transmittance that allows transmission of light in the second wavelength range (Y2),
the third wavelength range (Y3) is established to increase transmittance from the S wavelength to the M wavelength so that a portion of the visible light penetrates inside of the second region (<NUM>) to become light reflected toward the surface of the second region (<NUM>),
the transmittance is adjusted by a coloring agent contained in the second material, and
the first wavelength range (Y1) includes the emission wavelength to suppress the transmission of light from the first light source.