Patent Description:
A vehicle light is considered to form an irradiation pattern on a road surface around the vehicle.

Here, such a vehicle light is mounted on a vehicle and projects the irradiation pattern in a direction inclined relative to the road surface around the vehicle. Due to this, with the vehicle light, the distance from the installation position of the vehicle to the road surface varies depending on the position in the irradiation pattern, so that the irradiation pattern's part away from the vehicle becomes extremely dark.

Then, it has been considered that a vehicle light uses a micro array lens as a projection lens for projecting a light from a light source (see, for example, <CIT>). Then, adjusting a focal position of each lens portion in the micro array lens according to the distance to the road surface in the irradiation pattern can make the luminance distribution in the irradiation pattern as desired.

However, the above technology requires use of the micro array lens with the focal position of each lens portion adjusted according to the distance to the road surface, which results in a complicated configuration.

<CIT> relates to a warning device for an industrial truck, which, when arranged on the industrial truck, projects a pictorial information symbol, in particular a pictorial warning symbol, onto a roadway. The warning device is designed as a projector which has a light source which emits a luminous flux, and an image template of the information symbol to be projected, which can be illuminated by the luminous flux generated by the light source. The image template has at least one region that is transparent to the luminous flux of the light source and one region that shades the luminous flux of the light source, and the projector has a free-form lens arranged between the light source and the image template, wherein the free-form lens is designed such that the luminous flux of the light source is focused on the transparent region of the image template.

<CIT> relates to a vehicular lamp capable of making a desired light distribution on a light shielding member while having a simple configuration. The vehicular lamp comprises a first and second light source each having a light emitting surface and being arranged in a predetermined parallel direction; a single condenser lens for condensing light emitted from the first and second light source; a light shielding member provided with an irradiation slit through which light condensed by the condenser lens is partially passed; and a projection lens for projecting light passed through the light shielding member to form an irradiation pattern. The first and second light source are arranged with an interval equal to or larger than dimensions in the parallel direction on the light emitting surfaces, the condenser lens makes a light distribution in which a high light quantity area with the highest light quantity is single in the parallel direction.

We have appreciated that it would be desirable to provide a vehicle light which, while having a simple configuration, can make a desired luminance distribution in an irradiation pattern.

A vehicle light according to the present invention includes: a light source; a light condensing lens that condenses a light emitted from the light source; a filter that has an irradiation slit for allowing the light, which is condensed by the light condensing lens, to partially pass through; and a projection lens that forms the light having passed through the filter, into an irradiation pattern, wherein the irradiation slit has a farthest location that corresponds to a farthest portion projected at a farthest position in the irradiation pattern and a nearest location that corresponds to a nearest portion projected at a nearest position in the irradiation pattern, and the light condensing lens, on the filter, makes the farthest location brightest and the nearest location darkest in an upper-lower direction, and diffuses the light emitted from the light source more in a width direction, which is orthogonal to an optical axis direction and to the upper-lower direction, than in the upper-lower direction, in the projection lens, a focal plane relative to parallel rays of light from a radial position d that is defined as a predetermined interval in a radial direction from the optical axis La in the filter has a curvature radius r that decreases as the radial position d increases, and the focal plane has a curvature center set on an opposite side to the filter regardless of the radial position d.

The vehicle light of the present invention, while having a simple configuration, can make a desired luminance distribution in the irradiation pattern.

Hereinafter, Example <NUM> of a vehicle light <NUM> as an example of a vehicle light according to the present invention will be described with reference to the drawings. In order to make it easier to understand how the vehicle light <NUM> is installed, <FIG> illustrates the vehicle light <NUM> in relation to the vehicle <NUM>, with emphasis on the vehicle light <NUM>, which does not necessarily correspond to the actual appearance.

The vehicle light <NUM> of Example <NUM>, which is an embodiment of a vehicle light according to the present invention, will be described using <FIG>. As illustrated in <FIG>, the vehicle light <NUM> of Example <NUM> is used as a light of the vehicle <NUM> such as a car, and forms an irradiation pattern Pi on a road surface <NUM> around the vehicle <NUM> separately from a front light provided on the vehicle <NUM>. Here, the periphery of the vehicle <NUM> always includes a proximity area nearer to the vehicle <NUM> than the front light area illuminated by the front light provided on the vehicle <NUM>, and may partially include the front light area. In Example <NUM>, the vehicle light <NUM> is located in a light chamber on both the left and right sides of the front portion of the vehicle. The light chamber is so formed that an open front end of a lamp housing is covered with an outer lens. The vehicle light <NUM> is provided in the light chamber with an optical axis La inclined relative to the road surface <NUM>. This is due to the fact that the light chamber is located higher than the road surface <NUM>. In the following description, in the vehicle light <NUM>, a direction in which the optical axis La extends, which is the direction to irradiate the light, is referred to as an optical axis direction (Z in the drawing), a vertical direction seen when the optical axis direction is in a state of being along a horizontal plane is referred to as an upper-lower direction (Y in the drawing), and a direction (horizontal direction) orthogonal to the optical axis direction and the upper-lower direction is referred to as a width direction (X in the drawing) (see <FIG>, etc.).

As illustrated in <FIG>, in the vehicle light <NUM>, a light source portion <NUM>, a light condensing lens <NUM>, a filter <NUM>, and a projection lens <NUM> are housed in a housing <NUM>, and a heat radiation member <NUM> is attached to the housing <NUM>, constituting a projector-type road surface projection unit. The housing <NUM> includes a lower member 15a and an upper member 15b, and the upper member 15b is fitted to the lower member 15a with each of the above members (<NUM> to <NUM>) installed in the lower member 15a. In the housing <NUM>, a light condensing lens groove 15c to fit the light condensing lens <NUM> therein, a filter groove 15d to fit the filter <NUM> therein, and a projection lens groove 15e to fit the projection lens <NUM> therein are provided (illustrated only on the lower member 15a side).

In the light source portion <NUM>, a light source <NUM> is mounted on a substrate <NUM>. The light source <NUM> is composed of a light emitting element such as an LED (Light Emitting Diode), and is provided with an emission optical axis coinciding with the optical axis La. In Example <NUM>, the light source <NUM> emits amber monochromatic light (having a single peak in a graph in which the longitudinal axis is the light amount and the horizontal axis is the wavelength) in a Lambertian distribution with the optical axis La centered. The light source <NUM> is not limited to the configuration of Example <NUM>, as long as the color (wavelength band), mode of distribution, and the number of colors (the number of peaks in the graph described above) in the emitted light can be set as appropriate.

The substrate <NUM> lights the light source <NUM> by appropriately supplying the power from a lighting control circuit. In a state of being mounted on an installation face (a light source installation portion 16a) of the heat radiation member <NUM>, the substrate <NUM> is housed in the rear end portion of the housing <NUM> (the end portion opposite to the projection lens groove 15e in the optical axis direction).

The light condensing lens <NUM> condenses the light emitted from the light source <NUM> and condenses the light on the filter <NUM>. The light condensing lens <NUM> is formed by a biconvex lens in Example <NUM>, and an incident face 12a and an emission face 12b (see <FIG>, etc.) are each a free curved face. The optical setting in the light condensing lens <NUM> will be described below. In the light condensing lens <NUM>, mount flange portions 12c are provided at both ends in the width direction. Each of the mount flange portions 12c can be fitted into the light condensing lens groove 15c of the housing <NUM>. The light condensing lens <NUM> has a lens axis extending in the optical axis direction. That lens axis is an optical axis line that passes through the position of the largest thickness in the optical axis direction in the light condensing lens <NUM>. In the light condensing lens <NUM>, when the mount flange portion 12c is fitted into the light condensing lens groove 15c, the extending direction of the lens axis is caused to coincide with the optical axis La. The incident face 12a and the emission face 12b may be convex or concave, and are not limited to the configuration of Example <NUM>, as long as the light condensing lens <NUM> is a convex lens and satisfies the optical setting described below.

The filter <NUM> transmits the light from the light source <NUM> condensed by the light condensing lens <NUM> thereby to form the irradiation pattern Pi. As illustrated in <FIG> and the like, the irradiation pattern Pi has four irradiation drawing patterns Di aligned at equal intervals in a direction away from the vehicle <NUM>. Each irradiation drawing pattern Di is of a large open V-shape and is of a substantially equal size each other. When each irradiation drawing pattern Di is individually illustrated, the one farthest from the vehicle <NUM> is designated as a first irradiation drawing pattern Di1, and the second, third, and fourth irradiation drawing patterns Di2, Di3, and Di4, respectively, are designated as they sequentially approach the vehicle <NUM> from there. Due to this, in the irradiation pattern Pi, the first irradiation drawing pattern Di1 is the farthest portion and the fourth irradiation drawing pattern Di4 is the nearest portion. The irradiation pattern Pi can be made to look like an arrow pointing in a predetermined direction from the vehicle <NUM> by arranging each of the four irradiation drawing patterns Di with the vertices of the V-shaped pattern positioned in a substantially straight line. In Example <NUM>, the vehicle light <NUM> is provided at each of the left and right tip portions of the vehicle <NUM>, and forms the irradiation pattern Pi on the surrounding road surface <NUM> so as to point diagonally toward the front side of the vehicle <NUM> in the front/rear direction and toward the outside in the width direction. This irradiation pattern Pi can inform the surroundings of the direction in which the vehicle <NUM> is proceeding, and is formed in conjunction with a turn lamp in Example <NUM>.

In the filter <NUM>, as illustrated in <FIG>, a filter portion <NUM> is provided in a filter frame portion <NUM>. The filter frame portion <NUM> is in the form of a frame surrounding the filter portion <NUM> and can be fitted into the filter groove 15d of the housing <NUM> (see <FIG>).

The filter portion <NUM> is basically formed of a plate-shaped film member that blocks the transmission of light, and is provided with an irradiation slit <NUM>. The irradiation slit <NUM> partially transmits the light from the light source <NUM> condensed by the light condensing lens <NUM> thereby to form the light into the shape of the irradiation pattern Pi. The irradiation slit <NUM> is caused to correspond to the irradiation pattern Pi, and, in Example <NUM>, is composed of four slit portions <NUM>. The four slit portions <NUM> correspond, one-to-one, to the four irradiation drawing patterns Di, and are each made in the form of a V-shape that largely opens as each irradiation drawing pattern Di, and are made to have different sizes and different intervals from each other, unlike each irradiation drawing pattern Di. In detail, the vehicle light <NUM> is provided with the optical axis La inclined relative to the road surface <NUM>, so that the distance from the filter <NUM> and the projection lens <NUM> to the road surface <NUM> differs, so that with a projection on the road surface <NUM> by the projection lens <NUM>, each slit portion <NUM> (each irradiation drawing pattern Di which is the light transmitted therethrough) has a size and an interval which correspond to the distance. Due to this, the size and interval of each slit portion <NUM> are set according to the distance to the road surface <NUM> so that each slit portion <NUM> (each irradiation drawing pattern Di) has substantially equal size and substantially equal interval on the road surface <NUM>.

Further, each of the slit portions <NUM> is in a positional relation of a rotational symmetry around the optical axis La, relative to the positional relation of each irradiation drawing pattern Di of the irradiation pattern Pi. In detail, the vehicle light <NUM> is provided with each slit portion <NUM> in a positional relation of a rotational symmetry around the optical axis La relative to each irradiation drawing pattern Di, so that each irradiation drawing pattern Di is in a targeted positional relation on the road surface <NUM> because the projection lens <NUM> reverses and projects the filter <NUM> (irradiation slit <NUM>) on the road surface <NUM>. Due to this, concerning each slit portion <NUM>, a first slit portion <NUM> at the lowermost side in the upper-lower direction is the farthest location that corresponds to the first irradiation drawing pattern Di1 (farthest portion) of the irradiation pattern Pi. Then, concerning each slit portion <NUM>, a second slit portion <NUM> thereabove corresponds to the second irradiation drawing pattern Di2, a third slit portion <NUM> thereabove corresponds to the third irradiation drawing pattern Di3, and an uppermost fourth slit portion <NUM> is the nearest location that corresponds to the fourth irradiation drawing pattern Di4 (nearest portion) of the irradiation pattern Pi. In the filter <NUM> of Example <NUM>, in the upper-lower direction, the third slit portion <NUM> is provided across the optical axis La, the fourth slit portion <NUM> is provided thereabove, and the second slit portion <NUM> and the first slit portion <NUM> are provided below the third slit portion <NUM>.

Herein, as illustrated in <FIG>, the vehicle light <NUM> is designed to form, on both right and left sides of the vehicle <NUM>, the irradiation pattern Pi symmetrically with respect to a plane orthogonal to the width direction of the vehicle <NUM>. Due to this, as illustrated in <FIG>, the vehicle light <NUM> has two filters, that is, a filter 13R for the right side when installed in front of the right side of the vehicle <NUM>, and a filter <NUM> for the left side when installed in front of the left side of the vehicle <NUM>. The two filters 13R and <NUM> have the same configuration as each other, except that the irradiation slit <NUM> (each slit portion <NUM> thereof) is provided symmetrical with respect to the plane orthogonal to the width direction. The filter <NUM> (light transmitted through each slit portion <NUM> of the irradiation slit <NUM>) is projected on the road surface <NUM> by the projection lens <NUM>.

As illustrated in <FIG>, the projection lens <NUM> has a lens body portion <NUM>, which is a circular convex lens when viewed in the optical axis direction, and a flange portion <NUM> surrounding a periphery of the lens body portion <NUM>. In Example <NUM>, the lens body portion <NUM> is a free curved face in which an incident face 27a and an emission face 27b are each a convex face. The optical setting in the lens body portion <NUM> of the projection lens <NUM> will be described below. The projection lens <NUM> has a lens axis extending in the optical axis direction. This lens axis is an optical axis that passes through the position where the thickness in the optical axis direction is the largest in the lens body portion <NUM>. The incident face 27a and the emission face 27b each may be convex or concave, and are not limited to the configuration of Example <NUM>, as long as the lens body portion <NUM> is a convex lens and satisfies the optical setting described below.

The flange portion <NUM> protrudes from the lens body portion <NUM> in a radial direction with the optical axis La centered, and extends around the entire circumference in a circumferential direction with the optical axis La centered. The flange portion <NUM> is capable of being fitted into the projection lens groove 15e of the housing <NUM>. Concerning the projection lens <NUM>, when the flange portion <NUM> is fitted into the projection lens groove 15e, the extending direction of the lens axis is caused to coincide with the optical axis La.

The heat radiation member <NUM> is a heat sink member for releasing, to the outside, the heat generated at the light source <NUM>, and is formed of an aluminum die-casting or resin having thermal conductivity. This heat radiation member <NUM> has a light source installation portion 16a in which the light source portion <NUM> (substrate <NUM> thereof) is installed, and a plurality of heat radiation fins 16b. To the outside from each heat radiation fin 16b, the heat radiation member <NUM> radiates the heat generated by the light source portion <NUM> installed at the light source installation portion 16a.

The vehicle light <NUM> is assembled as follows with reference to <FIG>. First, the light source <NUM> is mounted on the substrate <NUM> thereby to assemble the light source portion <NUM>, and the light source portion <NUM> is fixed to the light source installation portion 16a of the heat radiation member <NUM>. Then, in the lower member 15a of the housing <NUM>, the light condensing lens <NUM> is fitted into the light condensing lens groove 15c, the filter <NUM> is fitted into the filter groove 15d, and the projection lens <NUM> is fitted into the projection lens groove 15e. Then, with the emission optical axis of the light source <NUM> coincided with the optical axis La and positioned, the light source installation portion 16a of the heat radiation member <NUM> is fixed to the rear end of the lower member 15a of the housing <NUM> while the substrate <NUM> is housed in the rear end portion of the lower member 15a. Then, fitting the upper member 15b on the upper side of the lower member 15a mounts the heat radiation member <NUM> while housing the light source portion <NUM>, the light condensing lens <NUM>, the filter <NUM>, and the projection lens <NUM> in the housing <NUM>. With this, the light condensing lens <NUM>, the filter <NUM>, and the projection lens <NUM> are arranged on the optical axis La of the light source <NUM> of the light source portion <NUM> in the above order from the light source <NUM> side in a predetermined positional relation, and the heat radiation member <NUM> is fixed to the light source portion <NUM> thereby to assemble the vehicle light <NUM>.

The vehicle light <NUM> is installed in the light chamber in a state in which the optical axis La is inclined relative to the road surface <NUM> around the vehicle <NUM> while being directed diagonally to the front side outside the vehicle <NUM> (see <FIG>). The vehicle light <NUM> can turn the light source <NUM> on and off as appropriate by supplying, from the substrate <NUM> to the light source <NUM>, the power from the lighting control circuit. The light from the light source <NUM> is condensed by the light condensing lens <NUM> thereby to irradiate the filter <NUM>, and after passing through the irradiation slit <NUM> (each slit portion <NUM>) thereof, is projected by the projection lens <NUM> thereby to form, on the road surface <NUM>, the irradiation pattern Pi in which the four irradiation drawing patterns Di are arranged in a substantially straight line.

Next, the optical setting of the light condensing lens <NUM> will be described using <FIG>. <FIG> shows that the darker the color, the relatively brighter, and the lighter the color, the relatively darker. First, the light condensing lens <NUM> basically irradiates within a setting range Sr (see <FIG>) in the filter <NUM> by condensing the light from the light source <NUM>. The setting range Sr is, in Example <NUM>, a range in which the irradiation slits <NUM> (each slit portion <NUM> thereof) of both the filter 13R for the right side and the filter <NUM> for the left side are provided, that is, a range covering the irradiation slits <NUM> of the filters 13R and <NUM> for both the left and right sides. The setting range Sr is an elliptical shape with the optical axis La at a center thereof (see <FIG>), and the light condensing lens <NUM> is also an elliptical shape with the optical axis La at a center thereof in accordance with the setting range Sr. Note that the setting range Sr is not limited to the configuration of Example <NUM>, as long as the shape of the setting range Sr is set according to the shape of the irradiation slit <NUM>, and the shape of the light condensing lens <NUM> is be set according to the setting range Sr. In the following, a direction orthogonal to the optical axis La is defined as a radial direction.

As illustrated in <FIG>, in a transverse cross-section including the optical axis direction and the width direction, within the range from the emission face 12b to the filter <NUM>, the light condensing lens <NUM>, concerning the light from the light source <NUM>, diffuses a light flux passing near the optical axis La in the radial direction, and parallelizes the light flux passing through the position away from the optical axis La in the radial direction. That is, the light condensing lens <NUM> diffuses the light near the optical axis La where the light amount is high due to being the Lambertian distribution, and condenses the light as outward from near the optical axis La. Then, in the transverse cross-section, that is, in the width direction, the light condensing lens <NUM> substantially evenly diffuses the light from the light source <NUM> within the setting range Sr of the filter <NUM>, so that the light amount distribution becomes substantially equal.

As illustrated in <FIG>, the light condensing lens <NUM> is a free curved face including an upper lens portion <NUM> and a lower lens portion <NUM> in the upper-lower direction with the optical axis La at the center. The upper lens portion <NUM> condenses the light from the light source <NUM> so as to cause the light to intersect with the optical axis La in a longitudinal cross-section including the optical axis direction and the upper-lower direction, as illustrated in <FIG>. The upper lens portion <NUM> causes at least the light flux near the optical axis La of the rays of light from the light source <NUM> to intersect with the optical axis La at the most filter <NUM> side, than other light fluxes, between the filter <NUM> and the projection lens <NUM>. Then, the upper lens portion <NUM> causes the majority of the light fluxes, excluding the light flux near the optical axis La, to intersect with the optical axis La beyond the projection lens <NUM>. As long as causing at least the light flux near the optical axis La to intersect with the optical axis La at the most filter <NUM> side, than other light fluxes, between the filter <NUM> and the projection lens <NUM>, the upper lens portion <NUM> may cause any light flux other than the above to intersect with the optical axis La either before or after the projection lens <NUM>. With this, above the optical axis La in the setting range Sr, the upper lens portion <NUM> evenly diffuses, in the upper-lower direction, the light from the light source <NUM> passing through the upper lens portion <NUM>; meanwhile, as nearer to the optical axis La in the radial direction, the upper lens portion <NUM> condenses more rays of light. In <FIG>, it appears that more light fluxes are condensed on the upper side, but this is because the light flux from the light source <NUM> is described according to the shape of the light condensing lens <NUM>, and in reality, according to the above setting, more rays of light are condensed as nearer to the optical axis La.

As illustrated in <FIG>, in the longitudinal cross-section illustrated above, the lower lens portion <NUM> condenses the light from the light source <NUM> so as to cause the light to intersect with the optical axis La. The lower lens portion <NUM> causes the light flux, of the rays of light from the light source <NUM>, which passes through the position farthest away from the optical axis La in the radial direction, to intersect with the optical axis La at the most filter <NUM> side between the filter <NUM> and the projection lens <NUM>. That is, concerning the light from the light source <NUM>, the lower lens portion <NUM> causes the light flux, which passes through the farthest away position from the optical axis La, to intersect with the optical axis La at the nearest position, and causes the light flux nearer to the optical axis La, to intersect with the optical axis La at the position away from the filter <NUM>. Then, the lower lens portion <NUM> causes the majority of the light fluxes, including the light flux near the optical axis La, to intersect with the optical axis La between the filter <NUM> and the projection lens <NUM>. As long as causing at least the light flux passing through the position farthest away from the optical axis La to intersect, between the filter <NUM> and the projection lens <NUM>, with the optical axis La, the lower lens portion <NUM> may cause any light flux other than the above to intersect with the optical axis La either before or after the projection lens <NUM>. With this, below the optical axis La in the setting range Sr, the lower lens portion <NUM> evenly diffuses, in the upper-lower direction, the light from the light source <NUM> passing through the lower lens portion <NUM>; meanwhile, as away from the optical axis La in the radial direction, the lower lens portion <NUM> condenses the light.

This light condensing lens <NUM>, with the optical setting described above, causes the light from the light source <NUM> passing through the light condensing lens <NUM> to be irradiated to the filter <NUM> (filter <NUM> for the left side in the example illustrated in the figure) within the setting range Sr, as illustrated in <FIG>. In that setting range Sr, according to the setting in the upper-lower direction in the light condensing lens <NUM> (its upper lens portion <NUM> and lower lens portion <NUM>), the first to fourth slit portions <NUM>, <NUM>, <NUM>, and <NUM> gradually change in brightness in the above order, so that the first slit portion <NUM> which becomes the farthest location is the brightest, and the fourth slit portion <NUM> which becomes the nearest location is the darkest, in the upper-lower direction. That is, the light condensing lens <NUM>, in the upper-lower direction, makes the position where the first slit portion <NUM> which becomes the farthest location is provided the brightest (as a peak), while gradually darkening as away from there, thereby to irradiate an area within the setting range Sr with the light from the light source <NUM>. Due to this, the light condensing lens <NUM>, by condensing the light from the light source <NUM>, gradually changes, in the longitudinal cross-section of the filter <NUM>, that is, in the upper-lower direction, the brightness across the optical axis La so as to make the farthest location brightest and the nearest location darkest.

Further, in the setting range Sr, with the setting in the transverse cross-section (width direction) in the light condensing lens <NUM>, the brightness in the width direction is made substantially uniform at each slit portion <NUM>, that is, at each position in the upper-lower direction. That is, the light condensing lens <NUM>, in the width direction, diffuses the light in a manner not to cause a difference in brightness compared to in the upper-lower direction, and causes the light from the light source <NUM> to irradiate within the setting range Sr. And, since the setting range Sr is set as described above, the irradiation slit <NUM> (each slit portion <NUM>) can be irradiated in a similar light flux distribution even when either of the filters 13R or <NUM> of the left or right side is used. The light transmitted through the filter <NUM>, that is, each slit portion <NUM> which is deemed as the light flux distribution is projected on the road surface <NUM> by the projection lens <NUM>.

Next, the optical setting of the projection lens <NUM> will be described using <FIG>. In <FIG>, (a) illustrates the case of the emission from a radial position of <NUM>, (b) illustrates the case of the emission from a radial position of <NUM>, and (c) illustrates the case of the emission from a radial position of <NUM>. The lens body portion <NUM> (projection lens <NUM>) sets a focal plane Fp, as illustrated in <FIG>. The focal plane Fp is a plane on which a point for condensing parallel rays of light from on the optical axis La and from a radial position d, which is defined as a predetermined interval and from the optical axis La in the radial direction, is located, at a position in the optical axis direction where the filter <NUM> is provided (the plane indicated by a sign <NUM>). The radial position d is the position in all radial directions, up, down, left, and right, with respect to the optical axis La, and the lens body portion <NUM> is similarly set in any direction orthogonal to the optical axis La. The lens body portion <NUM> is set so that as the radial position d becomes larger, a curvature radius r of the focal plane Fp becomes smaller that is, the curvature of the focal plane Fp becomes larger. Then, the lens body portion <NUM> sets the curvature center Cc (described at the top and in the middle) on the opposite side to the filter <NUM> (on the left of the focal plane Fp in <FIG>) relative to the focal plane Fp, regardless of the radial position d, and makes the focal plane Fp convex toward the projection lens <NUM> side. That is, the lens body portion <NUM> does not reverse the convex direction of the focal plane Fp even when the radial position d changes.

The lens body portion <NUM> of Example <NUM> sets the focal plane Fp as follows as an example. The lens body portion <NUM> has the curvature radius r of the focal plane Fp of about <NUM> for the parallel rays of light emitted from the radial position d of <NUM> and from on the optical axis La, as illustrated at the top of <FIG>. Further, the lens body portion <NUM> has the curvature radius r of the focal plane Fp of about <NUM> for the parallel rays of light emitted from the radial position d of <NUM> and from on the optical axis La, as illustrated in the middle of <FIG>. Then, the lens body portion <NUM> has the curvature radius r of the focal plane Fp of about <NUM> for the parallel rays of light emitted from the radial position d of <NUM> and from on the optical axis La, as illustrated at the bottom of <FIG>. When the lens body portion <NUM> reduces the curvature radius r of the focal plane Fp as the radial position d increases, it is sufficient that the value of the curvature radius r relative to the radial position d is appropriately set, and the lens body portion <NUM> is not limited to the configuration of Example <NUM>. In particular, the lens body portion <NUM> has the above setting of the focal plane Fp (relation between the radial position d and the curvature radius r), at a position (outside the near-axis area) where the radial position d is larger than the near-axis area (less than <NUM> at the radial position d in Example <NUM>). With this, the lens body portion <NUM> can suppress blurring by clarifying a contour of the irradiation pattern Pi with almost no change compared to the case where the lens body portion <NUM> is set on the entire surface including the near-axis area, thus making an efficient optical setting.

The projection lens <NUM> projects the irradiation slit <NUM> (each slit portion <NUM> thereof) of the filter <NUM> which is defined as the light flux distribution described above, thereby to form the irradiation pattern Pi, as illustrated in <FIG> illustrates the irradiation pattern Pi formed on a screen arranged orthogonally to the optical axis La, and <FIG> illustrates the irradiation pattern Pi formed on the road surface <NUM> inclined relative to the optical axis La. The contour of the irradiation pattern Pi is made clear on the screen, thus suppressing the blurring. This is due to the fact that setting the projection lens <NUM> (lens body portion <NUM>) as described above can reduce the effect of an image face curve of the projection lens <NUM>.

In addition, the contour of the irradiation pattern Pi is clear on the road surface <NUM> as well, thus preventing the blurring. This is due to the fact that setting the projection lens <NUM> (lens body portion <NUM>) as described above can reduce the effect that the distance to the road surface <NUM> changes due to the inclination of the road surface <NUM> relative to the optical axis La.

In particular, in the vehicle light <NUM> of Example <NUM>, since the light source <NUM> is a monochromatic light, the effect of chromatic aberration in the projection lens <NUM> can be greatly suppressed. Due to this, the projection lens <NUM> can form the irradiation pattern Pi with a clear contour and suppressed blurring.

In this irradiation pattern Pi, each irradiation drawing pattern Di, on the road surface <NUM>, is set to the luminance value illustrated in <FIG> illustrates the luminance values in the vicinity of the V-shaped vertex in each irradiation drawing pattern Di. In <FIG>, the luminance values on the longitudinal axis are logarithmic because it is generally known that the sense of brightness is proportional to the logarithm of luminance. As illustrated in <FIG>, the irradiation pattern Pi is logarithmically linear in the degree of change in brightness relative to the change in distance from the vehicle <NUM>, with the first irradiation drawing pattern Di1 farthest from the vehicle <NUM> being the darkest and the fourth irradiation drawing pattern Di4 nearest to the vehicle <NUM> being the brightest. That is, in the irradiation pattern Pi, each irradiation drawing pattern Di is arranged at an equal interval from each other, and the brightness is linearly increased in the order of the first irradiation drawing pattern Di1, the second irradiation drawing pattern Di2, the third irradiation drawing pattern Di3, and the fourth irradiation drawing pattern Di4.

To explain this operation, a vehicle light of a comparative example is used. The vehicle light of the comparative example shall be the same in configuration as the vehicle light <NUM>, and the setting range Sr of the filter <NUM>, that is, each slit portion <NUM>, shall be irradiated at uniform brightness with the light that is from the light source <NUM> and passed through the light condensing lens <NUM>. The vehicle light of the comparative example is similar to the vehicle light <NUM> of Example <NUM> in that at the projecting on the road surface <NUM>, it becomes darker in the order from the fourth irradiation drawing pattern Di4 at the nearest location to the third irradiation drawing pattern Di3, the second irradiation drawing pattern Di2, and the first irradiation drawing pattern Di1, but the change is not linear and it darkens rapidly nearer to the farthest location (the first irradiation drawing pattern Di1). This is due to the fact that in the irradiation pattern Pi projected by the projection lens <NUM>, the brightness changes in proportion to the square of the distance from the projection lens <NUM> to the projection face (in this example, the road surface <NUM>). Due to this, the vehicle light of the comparative example deteriorates the visibility of the farthest location (first irradiation drawing pattern Di1), and gives the viewer a sense of discomfort due to the rapid change in brightness.

Contrary to this, in the vehicle light <NUM> of Example <NUM>, the light from the light source <NUM> irradiates the filter <NUM> in a manner to gradually change the brightness of the setting range Sr of the filter <NUM> in the order of the first to fourth slit portions <NUM>, <NUM>, <NUM>, <NUM> so that the first slit portion <NUM> is the brightest and the fourth slit portion <NUM> is the darkest. That is, the vehicle light <NUM> brightens the first slit portion <NUM> most that corresponds to the first irradiation drawing pattern Di1 at the farthest location and darkens the fourth slit portion <NUM> most that corresponds to the fourth irradiation drawing pattern Di4 at the nearest location, contrary to the brightness in each irradiation drawing pattern Di of the irradiation pattern Pi. Then, the vehicle light <NUM>, by setting the brightness in the filter <NUM>, can mitigate the rapid change in brightness caused by the change in distance attributable to projection on the road surface <NUM> by the projection lens <NUM>, thus making it possible to linearize the change in brightness of each irradiation drawing pattern Di. Due to this, the vehicle light <NUM> can ensure the visibility of the farthest location (the first irradiation drawing pattern Di1), and can suppress a sense of discomfort of the viewer by making the linear change in brightness.

Next, the operation of this vehicle light <NUM> will be described using <FIG>. The vehicle light <NUM> is interlocked with the turn lamp, and when any of the left and right turn lamps is turned on, the light source <NUM> of the one on the turned-on side is turned on thereby to form the irradiation pattern Pi on the road surface <NUM>. For example, the example illustrated in <FIG> illustrates a scene in which the vehicle <NUM> is coming out of an alley with poor visibility and is about to turn left. In the vehicle <NUM>, the turn lamp on the left side is flashed, and thereby the vehicle light <NUM> installed on the front left forms the irradiation pattern Pi on the road surface <NUM>. Then, the driver of a vehicle 1A proceeding from the right side in front view of <FIG> can see the irradiation pattern Pi formed on the road surface <NUM>, even if the driver cannot see the vehicle <NUM>.

Further, in the vehicle <NUM>, the left and right vehicle light rays <NUM> are interlocked with the turn lamps, so that when a hazard lamp is turned on, the left and right vehicle light rays <NUM>, two in number, simultaneously form the irradiation patterns Pi on the road surface <NUM> (see <FIG>). Due to this, the vehicle light <NUM> can make a person around the vehicle <NUM> more reliably aware that the hazard lamp is turned on, compared to the case where only the left and right turn lamps are blinking.

The vehicle light <NUM> of Example <NUM> can obtain each of the following operational effects.

The vehicle light <NUM> is provided with the light condensing lens <NUM> that condenses the light emitted from the light source <NUM>, the filter <NUM> provided with the irradiation slit <NUM> that partially transmits the light condensed by the light condensing lens <NUM>, and the projection lens <NUM> that projects the light through the filter <NUM> thereby to form the irradiation pattern Pi. In the vehicle light <NUM>, the light condensing lens <NUM>, on the filter <NUM>, brightens the farthest location of the irradiation slit <NUM> most and darkens the nearest location of the irradiation slit <NUM> most in the upper-lower direction, and diffuses the light emitted from the light source <NUM> more in the width direction than in the upper-lower direction. Due to this, by setting the brightness in the filter <NUM>, the vehicle light <NUM> can mitigate the rapid change in brightness caused by the change in the distance from the projection lens <NUM> to the projection face. With this, in the vehicle light <NUM>, even when the optical axis La is provided in a manner to be inclined relative to the road surface <NUM>, the brightness distribution in the irradiation pattern Pi can be made as desired by the light condensing lens <NUM> setting the brightness on the filter <NUM>. And, since the vehicle light <NUM> makes the irradiation pattern Pi a desired luminance distribution by means of the light condensing lens <NUM> which is composed of the single incident face 12a and the emission face 12b, and the projection lens <NUM> which is composed of the single emission face 27b and the incident face 27a, the vehicle light <NUM> can be easily configured.

The vehicle light <NUM> has a plurality of irradiation drawing patterns Di in which the irradiation patterns Pi are arranged, and the irradiation slit <NUM> has the slit portion <NUM> that individually corresponds to the irradiation drawing patterns Di. With this, the vehicle light <NUM> can make each irradiation drawing pattern Di at a desired brightness by setting the brightness of each slit portion <NUM> with the light condensing lens <NUM>, making it possible to improve the visibility of the irradiation pattern Pi.

Further, in the vehicle light <NUM>, the light condensing lens <NUM>, on the filter <NUM>, diffuses the light from the light source <NUM> within the setting range Sr where the slit portion <NUM> is provided in the width direction. Due to this, the vehicle light <NUM>, as long as within the setting range Sr, can make the similar light flux distribution even if the position of each slit portion <NUM> is changed, for example, by using the left and right filters <NUM> in which the irradiation slits <NUM> (each slit portion <NUM>) are provided symmetrical with respect to the plane orthogonal to the width direction in Example <NUM>. With this, the vehicle light <NUM> can have a simple configuration while increasing the versatility.

In the vehicle light <NUM>, a plurality of slit portions <NUM> are arranged in the upper-lower direction, with the nearest location being the upper side and the farthest location being the lower side, in the irradiation slit <NUM>. Further, in the vehicle light <NUM>, the slit portion <NUM> is made smaller from the nearest location to the farthest location, and the number of slit portions <NUM> located below the optical axis La is larger than the number of slit portions <NUM> located above the optical axis La. Then, the vehicle light <NUM> is composed of the upper lens portion <NUM> and the lower lens portion <NUM> in the upper-lower direction. Additionally, in the vehicle light <NUM>, the upper lens portion <NUM> causes at least the light flux near the optical axis La to intersect with the optical axis La between the slit portion <NUM> and the projection lens <NUM>, and the lower lens portion <NUM> causes the light flux, which passes through the position farthest from the optical axis La, to intersect with the optical axis La on the most slit portion <NUM> side between the slit portion <NUM> and the projection lens <NUM>. Due to this, even when the vehicle light <NUM> is provided with the optical axis La inclined relative to the road surface <NUM>, the vehicle light <NUM> can make the plurality of irradiation drawing patterns Di of equal size and make each of them have a desired brightness. In addition, since the vehicle light <NUM> has a larger number of slit portions <NUM> on the lower side, which is the farthest location, than on the upper side, which is the nearest location, all the slit portions <NUM> can be put within an equal range from the optical axis La in the radial direction, thus making it possible to efficiently use the light from the light source <NUM>.

Concerning the vehicle light <NUM>, in the projection lens <NUM>, the focal plane Fp for the parallel rays of light from the filter <NUM> has the curvature radius that decreases as away in the radial direction from the vicinity of the optical axis La. Due to this, the vehicle light <NUM> can project the filter <NUM> (irradiation slit <NUM> (each slit portion <NUM>)) on the road surface <NUM> by reducing the effect of the image face curve of the projection lens <NUM> even when the optical axis La is provided in a manner to be inclined relative to the road surface <NUM>, and can form the irradiation pattern Pi on the road surface <NUM> with a clear contour and suppressed blurring.

In the vehicle light <NUM>, the focal plane Fp has the curvature center Cc set on the opposite side to the filter <NUM> regardless of the distance from the optical axis La in the radial direction. Due to this, the vehicle light <NUM> can form the irradiation pattern Pi on the road surface <NUM> with a clearer contour and more suppressed blurring, even when the optical axis La is provided in a manner to be inclined relative to the road surface <NUM>.

Accordingly, the vehicle light <NUM> of Example <NUM> as the vehicle light according to the present invention can make the luminance distribution in the irradiation pattern Pi as desired while having the simple configuration.

Although the vehicle light of the present invention has been described above based on Example <NUM>, the specific configuration is not limited to Example <NUM>, and design changes, additions, and the like are allowed as long as they do not depart from the scope of the appended claims.

Further, in Example <NUM>, the irradiation pattern Pi is constituted by aligning four irradiation drawing patterns Di at substantially equal intervals in the direction away from the vehicle <NUM>. However, provided that the irradiation pattern Pi is formed on the road surface <NUM> around the vehicle <NUM> and is the one that informs any person around the vehicle <NUM> of some intention of the driver, such as the one indicating the turn lamp and the hazard lamp in Example <NUM>, the pattern and the like may be anything as long as being set as appropriate and is not limited to the configuration of Example <NUM>. For example, the irradiation pattern Pi may be formed by the single irradiation drawing pattern Di, or may be formed by respective irradiation drawing patterns Di having different patterns from each other, or may vary in size and pattern in the arrangement order.

Further, in Example <NUM>, in order to make the light condensing lens <NUM> corresponding to the left and right filters 13R and <NUM>, the light condensing lens <NUM> diffuses the light from the light source <NUM> within the setting range Sr in which each slit portion <NUM> is provided in the width direction. However, the light condensing lens <NUM> is not limited to the configuration of Example <NUM>, as long as the light condensing lens <NUM> diffuses the light in the width direction thereby to make the luminance of the light, which transmits through each slit portion <NUM>, substantially equal. As an example of this, the light condensing lens <NUM> may be one that diffuses, in the width direction, the light from the light source <NUM> within the slit portion <NUM> of the filter <NUM> on any one of left and right sides, that is, may be one that condenses the light to a range caused to match the size of the slit portion <NUM> in the width direction and meanwhile that diffuses the light in the range, and is not limited to the configuration of Example <NUM>. In this way, when the light is condensed in the range of the slit portion <NUM> in the width direction, the light condensing lens <NUM> can gradually perform the brightening in the order of the fourth to first slit portions <NUM>, <NUM>, <NUM>, <NUM> more efficiently because the slit portion <NUM> is made smaller as the slit portion <NUM> approaches the farthest location.

Further, in Example <NUM>, in each slit portion <NUM>, the brightness in the width direction is made substantially uniform. However, the brightness in the width direction at each slit portion <NUM> may be anything as long as being appropriately set and is not limited to the configuration of Example <NUM>. For example, in each slit portion <NUM>, the vicinity of the apex that is made into the V-shape can be brightened. In this case, in the transverse cross-section, within the range from the emission face 12b to the filter <NUM>, the light condensing lens <NUM> shall, concerning the light from the light source <NUM>, with the light flux passing near the optical axis La in the radial direction being parallel, diffuses the light flux outside of it in the radial direction, and parallelizes the light flux passing through the position away from the optical axis La in the radial direction. In this way, the irradiation pattern Pi can emphasize the way in which the four irradiation drawing patterns Di point the direction of being arranged on a substantially straight line.

Claim 1:
A vehicle light (<NUM>) for forming an irradiation pattern on a road surface around the vehicle comprising:
a light source (<NUM>);
a light condensing lens (<NUM>) that condenses a light emitted from the light source (<NUM>);
a filter (<NUM>) that has an irradiation slit (<NUM>) for allowing the light, which is condensed by the light condensing lens (<NUM>), to partially pass through; and
a projection lens (<NUM>) that forms the light having passed through the filter (<NUM>), into an irradiation pattern (Pi), wherein
the irradiation slit (<NUM>) has a farthest location that corresponds to a farthest portion projected at a farthest position in the irradiation pattern (Pi) and a nearest location that corresponds to a nearest portion projected at a nearest position in the irradiation pattern (Pi),
characterized in that
the light condensing lens (<NUM>), on the filter (<NUM>), makes the farthest location brightest and the nearest location darkest in an upper-lower direction, and diffuses the light emitted from the light source (<NUM>) more in a width direction, which is orthogonal to an optical axis direction and to the upper-lower direction, than in the upper-lower direction, and
in the projection lens (<NUM>), a focal plane (Fp) relative to parallel rays of light from a radial position (d) that is defined as a predetermined interval in a radial direction from the optical axis (La) in the filter (<NUM>) has a curvature radius r that decreases as the radial position d increases, and the focal plane (Fp) has a curvature center (Cc) set on an opposite side to the filter (<NUM>) regardless of the radial position (d).