JP2018120834A - Lighting fixture unit and vehicular lighting fixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for downsizing a vehicular lighting fixture comprising a direct optical system while securing utilization efficiency of light.SOLUTION: A lighting fixture unit (5) comprises a projection lens (11) and a light source (7) arranged so as to emit light toward the projection lens (11). The projection lens (11) consists of a first lens (110) arranged on the side of the light source (7) and a second lens (120) arranged in front of the first lens (110). The curvature of an incident surface (110A) of the first lens (110) is smaller than the curvature of an emitting surface (110B) thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicular lamp, and more particularly to a lamp unit having a direct-type optical system and a vehicular lamp including the lamp unit.

  Conventionally, a vehicular lamp having a so-called direct-light type optical system in which light from a light source such as a light emitting diode is directly projected by a projection lens is known. Generally, in a direct-light type optical system, light from a light source is emitted in a wide angle range, but since no reflector is provided, there is light that goes toward the outer periphery without entering the projection lens, and from the light source The utilization efficiency of the emitted light is low.

  Patent Document 1 discloses a vehicle headlamp including a lamp unit in which a light transmitting member is disposed in an area that avoids a light path that is directly incident on a projection lens from a light source to improve the light use efficiency. Yes. Patent Document 2 discloses a vehicle headlamp provided with a lamp unit in which a cover body is disposed so as to surround the light source to prevent the occurrence of leakage light related to the light source light and the light use efficiency is improved. Disclosure.

  By the way, when considering reducing the size of a vehicular lamp having a direct-lighting optical system, reducing the lens diameter reduces the light utilization efficiency, and shortening the lens to improve the light utilization efficiency reduces the lens thickness. There is a trade-off that it increases and costs increase.

  Therefore, the inventor proposes the present invention based on the idea that if the projection lens is composed of two lenses, the diameter of the lens can be reduced while ensuring the light use efficiency.

JP 2013-254623 A JP 2012-119229 A

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for reducing the size of a vehicular lamp having a direct-light optical system while ensuring the light use efficiency.

  To achieve the above object, a lamp unit according to one aspect of the present invention includes a projection lens and a light source arranged to emit light toward the projection lens. The projection lens includes a first lens disposed on the light source side and a second lens disposed in front of the first lens, and the curvature of the incident surface of the first lens is determined by the exit surface thereof. It is characterized by being smaller than the curvature.

  In the above aspect, it is also preferable that the light source is disposed closer to the projection lens than when the projection lens is configured by a single lens.

  In the above aspect, it is also preferable that the curvature of the incident surface of the first lens is zero.

  In the above aspect, it is also preferable that the curvature of the entrance surface of the second lens is larger than the curvature of the exit surface.

  In the above aspect, it is also preferable that the light source is a semiconductor light emitting element including a light emitting surface arranged toward the projection lens.

  Moreover, the vehicle lamp which concerns on another aspect of this invention is provided with the lamp unit which concerns on the said aspect.

  According to said structure, a vehicle lamp can be reduced in size, ensuring the utilization efficiency of light.

1 is a vertical longitudinal sectional view of a vehicular lamp according to one embodiment of the present invention. It is a front view of the 1st lens which concerns on the Example. It is a figure for comparing the lamp unit which concerns on the Example, and the conventional lamp unit.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a vehicular lamp according to the present invention will be described based on examples with reference to the drawings.

  In the present specification, terms indicating directions such as “up”, “down”, “front”, “back”, “left”, “right”, and the like are included in the embodiment of the present invention unless otherwise specified. The direction in the state in which the vehicle lamp concerned was attached to the vehicle is meant.

Example 1
FIG. 1 is a cross-sectional view schematically showing an internal configuration of a vehicular lamp 1 according to the present embodiment. The vehicular lamp 1 is a vehicular headlamp that is attached to the front of a vehicle and illuminates the front of the vehicle.

  As shown in FIG. 1, a vehicular lamp 1 includes a container-shaped lamp body 2 having an opening at the front, and a transparent front cover 3 attached to the opening of the lamp body 2. A lamp chamber 4 is formed.

  A lamp unit 5 is disposed in the lamp chamber 4, and the lamp unit 5 is attached to the lamp body 2 via an aiming mechanism 6 provided on the rear inner surface of the lamp body 2. The lamp unit 5 includes a light source 7, a substrate 8, a support member 9, a heat sink 10, a projection lens 11, a lens holder 12, and a sub lens unit 13.

  The light source 7 is an LED as a semiconductor light emitting element having a rectangular light emitting surface, and is mounted on the substrate 8 with the light emitting surface facing the projection lens 11 at the rear focal point of the projection lens 11 and via a signal line (not shown). Light is emitted in response to a control signal input from the vehicle-side control unit. Note that the type of the light source 7 is not limited to this, and an incandescent bulb, a discharge tube, another diode, or the like may be used.

  The substrate 8 is fixed to the front side of the support member 9, holds the light source 7, and supplies current to the light source 7. The heat sink 10 is fixed to the rear surface side of the support member 9 and is configured to release heat generated in the substrate 8 as the light source 7 emits light. The support member 9 is fixed to the lamp body 2 via the aiming mechanism 6.

  The projection lens 11 includes a first lens 110 disposed on the light source 7 side and a second lens 120 disposed in front of the first lens 110. The first lens 110 and the second lens 120 are configured to have the same diameter, and are fixed to the front of the support member 9 by a lens holder 12 fixed to the front surface of the support member 9.

  As shown in FIG. 2, the first lens 110 includes a lens region 111 that receives light from the light source 7 and emits the light toward the second lens 120, and a flat flange that extends in a donut shape around the lens region 111. Region 112. In the lens region 111, the rear surface and the front surface of the lens region 111 are the entrance surface 110A and the exit surface 110B of the first lens 110, respectively. It is a convex lens having refractive power. Therefore, the front surface of the first lens 110 is configured such that the lens region 111 protrudes from the flange region 112. The curvature of the incident surface 110A is smaller than the curvature of the exit surface 110B. In particular, the curvature of the incident surface 110A is preferably 1/30 or less, more preferably 0, when the curvature is expressed by the reciprocal of the radius of curvature (mm). The first lens 110 is configured such that the flange region 112 is held by the lens holder 12. The light source 7 is disposed so as to be closer to the projection lens than in the case where the projection lens is constituted by a single lens. This point will be described in detail later.

  In general, if the curvature of the entrance surface of the lens is large, the amount of light reflected on the entrance surface increases, so the light utilization efficiency is low.If the curvature is small, the light utilization efficiency is low because less light is reflected on the incidence surface. Will improve. Therefore, in this embodiment, since the curvature of the incident surface 110A of the first lens 110 is small, the light use efficiency can be improved, and the same light distribution can be obtained even when the diameter of the projection lens is reduced.

  The second lens 120 is disposed in front of the first lens 110, that is, in front of the vehicle so as to share the optical axis Ax with the first lens 110. When the vehicle is observed from the front, the front cover is arranged. 3 is visible. The second lens 120 is a convex lens having a positive refractive power that converges the light from the first lens 110 incident from the incident surface 120A and emits the light from the output surface 120B as substantially parallel light. And it is preferable that the curvature of 120 A of entrance surfaces is larger than the curvature of the output surface 120B. With such a configuration, the impression of projecting forward as a spherical shape of the emission surface 120B of the second lens 120 is softened, and the design of the front surface of the second lens 120 constituting the projection lens 10 can be improved.

  The first lens 110 and the second lens 120 are formed by injection molding in which a transparent resin such as acrylic or polycarbonate is poured into a mold, and cooled and solidified. However, the material of the lens is not limited to these, and any material may be used as long as it can converge the light emitted from the light source 7 by refraction to form a desired light distribution pattern, and may be glass, for example. The lens region 111 and the flange region 112 of the first lens 110 may be formed of the same material or different materials.

  The sub lens unit 13 has the same configuration as the sub lens unit disclosed in Patent Document 1. That is, the illustrated upper and lower sub-lenses 13A and 13B and a pair of left and right sub-lenses (not illustrated) are arranged in a region that avoids the path of light that directly enters the lens region 111 of the first lens 110 from the light source 7. The light that is configured and is not directly incident on the lens region 111 of the first lens 110 out of the light emitted from the light source 7 is emitted toward the lens region 111 of the first lens 110. The sub lens unit 13 is provided to further increase the light capturing efficiency, but is not an essential configuration in the present invention.

  Next, the function of the vehicular lamp according to the present embodiment will be described. The light emitted from the light source 7 is incident on the incident surface 110A of the first lens 110 (in the lens region 111 thereof). After the light source light, light that does not directly enter the lens region 111 of the first lens 110 enters the sub-lens unit 13 and is emitted toward the lens region 111 of the first lens 110. The light incident on the first lens 110 is converged by the positive refractive power, emitted from the emission surface 110B of the first lens (the lens region 111) toward the second lens 120, and the second lens 120. Is incident on the incident surface 120A. Thereafter, the light is further converged by the positive refractive power of the second lens, and is irradiated to the front of the vehicle as light substantially parallel to the emission surface 120B.

  Thus, the lamp unit 5 according to the present embodiment constitutes a direct-light optical system in which the light source light enters the projection lens 11 without passing through the reflector. Further, the vehicular lamp 1 according to the present embodiment is a so-called high beam vehicular headlamp that irradiates a wide area and a distant area in front of the vehicle with a relatively high illuminance.

  In order to explain the principle of the present embodiment, first, a conventional lamp unit using a single projection lens that forms a predetermined light distribution L1 will be described. FIG. 3A shows the arrangement of the projection lens 200 and the light source 7 and the light path of such a lamp unit. That is, the light source 7 is arranged at the rear focal point F1 of the projection lens 210. In the figure, D1 represents the aperture of the projection lens 200, d1 represents the distance between the projection lens 200 and the light source 7, and θ1 represents the effective illumination angle of the light source light that can be used by the projection lens 200.

  Next, a lamp unit in which the lamp unit, the light source 7, and the projection lens 11X in FIG. 3A are arranged in the same layout and the projection lens 11X is configured by two lenses will be considered. For convenience of explanation, the first lens 110X and the second lens 120X are lenses having the same diameter as the projection lens 200 of FIG. As shown in FIG. 3B, the light source is disposed at the rear focal point F2 of the projection lens 11X as a combination lens of the first lens 110X and the second lens 120X. In the figure, D2 is the aperture of the first lens 110X and the second lens 120X, d2 is the distance between the first lens 110X and the light source 7, and θ2 is the light source light that can be used by the projection lens 11. , And as described above, D2 is equal to D1. At this time, the distance d2 between the first lens 110X and the light source 7 is shorter than that in FIG. Therefore, the irradiation angle θ2 becomes larger than θ1, and the light distribution amount L2 increases as the use efficiency of the light source light is higher.

  Furthermore, if the first lens 110Y and the second lens 120Y are configured such that the distance d3 between the light source 7 and the first lens is shorter than d2, as shown in FIG. The larger the amount, the higher the light utilization efficiency and the further the light distribution. In the figure, D3 indicates the apertures of the first lens 110Y and the second lens 120Y, θ3 indicates the irradiation angle of the light source light that can be used by the projection lens 11Y, F3 indicates the focal point of the projection lens 11Y, and D3 Is equal to D1. In FIG. 3 (c), the light use efficiency is higher than in FIG. 3 (a) and the light distribution L3 increases. Therefore, the aperture of the lens, that is, the effective irradiation angle θ3 is made equal to θ1, By making the utilization efficiency equal to that in FIG. 3A, it is possible to secure the same light distribution L1 ′ as the light distribution L1 in the case of FIG. Therefore, the apertures of the first lens and the second lens can be set smaller than D3. Using this principle, in the present embodiment, the lens region 111 and the second lens 120 of the first lens 110 are configured to correspond to the width of the optical path, the light source is the projection lens, and the projection lens is a single lens. By arranging the projection lens closer to the projection lens than in the case of the above configuration, it is possible to reduce the diameter of the projection lens while ensuring the light use efficiency.

Thus, according to the present embodiment, for example, a lamp unit that can use light more efficiently than a conventional lamp unit having a distance from the light source to the projection lens of 33 mm and a lens diameter of 50 mm is provided as a light source. The distance from the projection lens to the projection lens can be 30 mm, and the lens aperture can be 40 mm.

  According to the present embodiment, since the refractive power can be dispersed, the thickness of each lens can be reduced, and the manufacturing cost for the projection lens can be reduced.

  The embodiments of the present invention have been described based on the examples. However, the examples can be modified based on the common general knowledge of those skilled in the art, and such modifications are included in the scope of the present invention. .

  For example, the lamp unit 5 of the present invention is not limited to the use for forming a high beam light distribution pattern, and can be applied to any vehicular lamp 1 including a direct-light optical system such as a fog lamp and a cornering lamp.

DESCRIPTION OF SYMBOLS 1 Vehicle lamp 5 Lamp unit 7 Light source 11 Projection lens 110 1st lens 110A Incident surface 110B Output surface 111 Lens area 112 Flange area 120 2nd lens 120A Incident surface 120B Output surface

Claims (6)

In a lamp unit comprising a projection lens and a light source arranged to emit light toward the projection lens,
The projection lens includes a first lens disposed on the light source side and a second lens disposed in front of the first lens,
The lamp unit, wherein a curvature of an entrance surface of the first lens is smaller than a curvature of an exit surface thereof.   The lamp unit according to claim 1, wherein the light source is disposed so as to be closer to the projection lens than when the projection lens is formed of a single lens.   The lamp unit according to claim 1 or 2, wherein a curvature of an incident surface of the first lens is zero.   The lamp unit according to any one of claims 1 to 3, wherein a curvature of an incident surface of the second lens is larger than a curvature of an exit surface thereof.   The lamp unit according to any one of claims 1 to 4, wherein the light source is a semiconductor light emitting element including a light emitting surface disposed toward the projection lens.   A vehicle lamp comprising the lamp unit according to claim 1.

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