JP2010061916A - Led light source lamp for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems that a projector type lamp using an LED light source uses a projection lens having the same shape as in using a filament light source as an approximately point light source, and so it cannot produce ideal light distributing characteristics because of different light amount distribution after reflection from an elliptical reflecting plane. <P>SOLUTION: By tracing the reflecting direction of beams and the intensity distribution in the elliptical reflecting plane from the LED light source arranged at a predetermined position and designing the shapes of an incident plane and an emission plane of the projection lens for determining the refracting direction of the beams to produce the ideal light distributing characteristics in accordance with the results, the projector type lamp using the LED light source produces desired light distribution. This solves the issues. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a so-called conventional projector lamp in which the central portion of the light source is brightest, such as the filament of a halogen bulb and the arc of a metal halide discharge lamp, and therefore the light focused on the second focal point is brightest on the optical axis. The object of the present invention is to provide a projection lens suitable for a projector lamp of an LED light source that can be mounted with the light emitting direction substantially upward.

  The conventional projector-type headlamp 90 uses a so-called spheroidal reflecting mirror 91 in which an ellipse is rotated on the major axis and divided into two on the minor axis. Since the projection lens 93 projects a cross-sectional shape in which the lower half portion is shielded by the shade 92 of the light beam focused on the two focal points, the light distribution characteristic is adopted here. Since the light emission state is different from the case where a light bulb or the like is used as a light source, there is a problem that appropriate light quantity distribution cannot be performed and visibility in the distance is lowered.

  Therefore, as shown in FIG. 6, the LED light source 94 is appropriately tilted rearward so that the center portion of the LED light source 94 having a Lambertian distribution, that is, the brightest portion substantially coincides with the optical axis X. The shape of the reflecting mirror 91 and the projection lens 93 has also been devised to emit light with substantially the same intensity in almost all directions around the light source, such as conventional halogen lamps and metal halide lamps, as much as possible. Ingenuity has been devised to bring it closer to the characteristics of conventional projector lamps.

As a means for solving the problem, there is basically disclosed a vehicular lamp in which the shape of the projection lens 93 is a concave cylindrical surface toward the light source side. As shown by the optical characteristic DO, the light quantity in the left and right peripheral portions is still insufficient. In FIG. 6, reference numeral 95 denotes a lens holder for holding the projection lens 93, and the light beam indicated by reference numeral 96 in the drawing is a light beam for reading an overhead sign placed above the road surface. It is.
JP 2008-103192 A

  However, in the above-described conventional projector-type headlamp, as described above, the filament, arc, etc., which are usually arranged on the optical axis are usually brightest, and the filament, arc, etc. are centered radially. Since light is radiated, it is easy to predict the portion with the highest luminance in terms of light distribution characteristics. For example, when no shade is provided, the brightness is almost concentric.

  Therefore, as described above, when a halogen light bulb, a metal halide discharge lamp or the like is employed as a light source, even if not particularly configured, a light distribution that does not cause much inconsistency in light distribution as a headlamp can be obtained. When a light source is used as a light source, an amber cyan distribution is generated by surface emission, which causes a problem in light distribution formation, for example, it is difficult to obtain the maximum value of illuminance in the horizontal front direction.

  In the present invention, as a specific means for solving the above-described conventional problems, an LED light source disposed with a light emitting surface facing substantially upward, the LED light source as a focal point, a single focal point, and an axis substantially The projection lens, comprising: an elliptical reflecting surface installed horizontally; a shade provided in the vicinity of a second focal point of the elliptical reflecting surface; and a projection lens having a focal point in the vicinity of the shade; Is a lens configuration in which the direction and intensity of light incident from the second focal point is considered, and the direction of light emitted from the projection lens is determined for each incident light direction and intensity. The problem is solved by providing a lamp for an LED light source vehicle.

  According to the present invention, an LED light source for designing a projection lens in which light is incident on the projection lens, the direction (incident angle), and the direction in which the light is emitted (exit angle) is determined in advance in consideration of the intensity of each light. Irradiation even when changing from a so-called point light source with a conventional light source as the center of brightness to a light source that emits light with a Lambertian distribution, such as an LED light source. As a vehicular lamp capable of obtaining a width, a central illuminance, and the like, the problems are solved.

  Below, this invention is demonstrated in detail based on embodiment shown in a figure. What is indicated by reference numeral 1 in FIG. 1 is a vehicular lamp according to the present invention, and this vehicular lamp 1 is configured as a projector type in which an LED light source 2 is employed as a light emission source. Is the same as

  Therefore, unlike conventional filaments that emit light almost entirely from the light emitting source, light is emitted only on the light emitting surface 2a side of the LED light source 2, so that the LED light source 2 is substantially on the light emitting surface 2a side. Corresponding to this, the elliptical reflecting surface 3 is provided so that only the substantially upper half part covers the LED light source 2.

  As described above, since the light from the LED light source 2 has a Lambertian distribution in which the front surface of the LED light source 2 is brightest, the first focal point f1 of the elliptical reflecting surface 3 is used. When the light is arranged vertically upward, the reflected light has a strong downward component and is partially reflected by the incident surface 5a of the projection lens 5, resulting in insufficient illuminance on the front of the vehicle. As shown in FIG. 1, it is appropriately tilted backward and adjusted so that the illuminance at the center increases.

  A shade 4 is provided in the vicinity of the second focal point f2 of the elliptical reflecting surface 3, and in principle, the light from the lower half of the elliptical reflecting surface 3 is shielded so that the driver of the oncoming vehicle It is the same as that of the prior art in that it does not cause glare.

  Here, in the present invention, the projection lens 5 is designed as shown in FIG. 2. In this embodiment, basically, the surface of the projection lens 5 closer to the elliptical reflecting surface 3 side, that is, the LED light source. 2 is designed from the light incident surface 5a side.

  At this time, if the incident surface 5a is orthogonal to the central axis X of the vehicular lamp 1, the light once focused on the second focal point f2 reaches the incident surface 5a of the projection lens 5. Sometimes, for example, refraction occurs due to the refractive index of air (= 1) and the refractive index of the member on which the projection lens 5 is formed (for example, 1.4).

  Here, as described above, it is normal that (refractive index of air) <(refractive index of the projection lens 5), so that the light from the LED light source 2 passes through the incident surface. The divergence angle α is narrowed by a prescribed value according to Snell's law. Note that FIG. 2 shows a horizontal section in a state where the vehicular lamp 1 is attached to the vehicle body.

  In the conventional example, a convex lens such as an aspherical surface is also provided on the exit surface 5b, but in the present invention, in consideration of the direction of each light refracted by the entrance surface 5a, The exit-side curved surface, that is, the exit surface 5b is set so that they are directed in a desired direction.

  Therefore, the curved surface is set so as to match the purpose of the vehicle to which the vehicle lamp 1 is mounted. For example, when a wide irradiation angle is required, the exit surface 5b is made incident surface 5a as shown in FIG. The traveling direction of the light is not substantially changed even when it is radiated into the atmosphere from the member formed with the projection lens 5 formed as a curved surface orthogonal to the light passing through the light.

  FIG. 1 shows this state as a perspective view, and the projection lens 5 of the present invention has a smaller thickness and a larger aperture than the conventional vehicle lamp 90 shown in FIG. It gives a new feeling to the viewer. In this embodiment, the exit surface 5b has been described as having no change in the traveling direction of light. However, the present invention is not limited to this, and the point is that each light once refracted by the entrance surface 5a is used. In addition, the gist is to provide an optimum directionality at the exit surface 5b.

  FIG. 3 shows the projection lens 5 of the present invention in more detail, (a) is a front view, (b) is an AA cross section of (a), that is, a horizontal cross section, (c) ) Is a BB cross section of (a), that is, a vertical cross sectional view. As described above, in the present invention, the surface on the emission surface 5b side is set so as to emit substantially parallel light in the vertical section, and in the horizontal section, as it goes from the center to the outside so as to obtain diffused light. The surface on the exit surface 5b side is set so that the radius of curvature of the exit surface 5b is increased.

  FIG. 4 shows the light distribution characteristic DN of the vehicular lamp 1 according to the present invention shown in FIGS. 1 and 2, and it is shown later by not using the conventional lens-shaped exit surface. Compared with the light distribution characteristic DO of the conventional example shown in FIG. 5, a remarkably wide irradiation angle is obtained, and an improvement in visibility and the like can be expected.

  FIG. 5 shows another embodiment of the vehicular lamp 1 according to the present invention in a horizontal cross section. In this embodiment, the incident surface 6 a of the projection lens 6 is relative to the central axis X of the vehicular lamp 1. In the state where the vehicular lamp 1 is attached to the vehicle, the vehicular lamp 1 is formed as a vertical cylindrical surface having the second focal point f2 as a substantial center.

  Accordingly, the light from the second focal point f2 enters the projection lens 6 in a substantially vertical state, and the amount of change in the traveling direction of the light is extremely reduced. This means that when the light enters the projection lens 6 from the LED light source 2, the incident surface 6a is incident with almost no light loss.

  In this embodiment, a curved surface is formed on the emission surface 6b side to refract light incident on the projection lens 6 from the LED light source 2 in a desired direction, for example, the vertical direction and the horizontal direction. Note that the incident surface 6a does not have to be completely vertical, and may be inclined to refract light as appropriate or may be inclined in the left-right direction, for example.

  According to the present invention, each of the light incident on the incident surfaces 5a and 6a is configured to be directed in a desired direction. First, light incident on the projection lenses 5 and 6 from the second focal point is incident. While increasing the rate, the internal reflection can also be reduced, and the amount of light as the vehicular lamp 1 can be increased. Further, by combining shapes other than the spherical surface, for example, the degree of freedom is increased in forming a light distribution with a wide irradiation width. Furthermore, it is possible to change the shape of the conventional uniform projector-type lamp and increase the degree of freedom in design.

It is a perspective view showing an embodiment of a vehicular lamp concerning the present invention in an important section. It is explanatory drawing which shows embodiment of the projection lens which is the principal part of the vehicle lamp which concerns on this invention. It is explanatory drawing which shows embodiment of the projection lens of the vehicle lamp which concerns on this invention. It is a graph which shows the light distribution characteristic of the vehicle lamp which concerns on this invention. Similarly, it is explanatory drawing which shows another embodiment of the projection lens which is the principal part of the vehicle lamp which concerns on this invention. It is explanatory drawing which shows the structure of the vehicle lamp of a prior art example. It is a graph which shows the light distribution characteristic of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle lamp 2 ... LED light source 3 ... Elliptic reflection surface 4 ... Shade 5, 6 ... Projection lens 5a, 6a ... Incident surface 5b, 6b ... Output surface

Claims (4)

  An LED light source disposed with its light emitting surface facing substantially upward; an elliptical reflective surface that is arranged with the LED light source as a focal point and coincident with one focal point and whose axis is substantially horizontal; and a second of the elliptical reflective surface A vehicular lamp comprising a shade provided in the vicinity of a focal point and a projection lens having a focal point in the vicinity of the shade, the projection lens taking into account the direction and intensity of light incident from the second focal point, An LED light source vehicular lamp characterized by having a lens configuration in which the direction of light emitted from the projection lens is determined for each direction and intensity of each incident light.   2. The LED light source vehicle lamp according to claim 1, wherein the projection lens has a light distribution characteristic mainly on a surface on an emission side.   3. The LED light source vehicle lamp according to claim 1, wherein the projection lens uses light in the vertical direction as substantially parallel light and light in the parallel direction as diffused light. 4.   4. The LED light source vehicle lamp according to claim 3, wherein a radius of curvature of the projection-side surface of the projection lens increases toward the outside in a horizontal section. 5.

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