JP2014143057A - Projection lens and lighting fixture unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection lens which forms a light distribution pattern different from the shape of a light emission surface of a light emission part.SOLUTION: A projection lens 12 is a projection lens used in a vehicular lighting fixture, and includes an incident surface 12c on which light emitted from a light source is incident, and an emission surface 12d from which the light incident on the incident surface is emitted toward the front of the lighting fixture. The incident surface 12c and the emission surface 12d are configured such that a horizontal plane focal length Fh to a rear focal point F in a horizontal cross section including the optical axis Ax is different from a vertical plane focal length Fv to the rear focal point F in a vertical cross section including the optical axis Ax.

Description

  The present invention relates to a projection lens, and more particularly to a projection lens mounted on a vehicle.

  2. Description of the Related Art Conventionally, in a vehicle headlamp configured to form a light distribution pattern having a predetermined cut-off line at the upper end, a lamp unit used for forming the cut-off line has been devised (Patent Document 1). reference).

  This lamp unit has a projection lens arranged on an optical axis extending in the vehicle front-rear direction, and a light emitting chip having a lower end edge formed in a straight line. The projection lens emits light from a point on the optical axis at the lower end edge of the light emitting chip as parallel light within a cross section orthogonal to the lower end edge of the light emitting chip, while the lower end edge of the light emitting chip. In the cross section parallel to the light emitting chip, the light from the point on the optical axis at the lower edge of the light emitting chip is emitted as diffused light.

JP 2005-108555 A

  The above-described lamp unit emits light from a point on the optical axis at the lower end edge of the light emitting chip as diffused light in a cross section parallel to the lower end edge of the light emitting chip. The light / dark boundary at the horizontal end of the light distribution pattern tends to be unclear.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a projection lens that forms a light distribution pattern different from the shape of the light emitting surface of a light source.

  In order to solve the above problems, a projection lens according to an aspect of the present invention is a projection lens used in a vehicular lamp, and includes an incident surface on which light emitted from a light emitting unit is incident and light incident from the incident surface Has an exit surface that exits toward the front of the lamp. The entrance surface and the exit surface are configured such that the horizontal plane focal length Fh with respect to the rear focal point in the horizontal cross section including the optical axis is different from the vertical plane focal length Fv with respect to the rear focal point in the vertical cross section including the optical axis.

  According to this aspect, it is possible to form a light distribution pattern that is different from the shape of the light emitting surface of the light emitting portion near the focal point. In addition, the projection lens can project a light distribution pattern in which the aspect ratio is changed while maintaining the luminous intensity distribution of the light emitting surface of the light emitting unit.

  The incident surface and the exit surface are 0.9 × | h | <Fv ×, where θ is the exit angle of the light beam emitted from the rear focal point with respect to the optical axis, and h is the distance between the light beam emitted from the projection lens and the optical axis. It may be configured to satisfy sin θ <1.1 × | h | 0.9 × | h | <Fh × sin θ <1.1 × | h |. Thereby, an object near the focal point (for example, the light emitting surface of the light source) can be clearly imaged.

  The entrance surface and the exit surface may be configured to satisfy Fv> 1.2 × Fh. As a result, a light distribution pattern having a large horizontal expansion rate can be realized.

  The entrance surface and the exit surface may be configured by free-form surfaces.

  Another embodiment of the present invention is a lamp unit. This lamp unit includes the above-described projection lens and a light emitting unit disposed in the vicinity of the rear focal point of the projection lens. The light emitting unit includes a plurality of light emitting units arranged in an array, and is configured such that a part of the light emitting units can be turned off during lighting. Thereby, even when a part of the light emitting part is turned off, the light / dark boundary in the light distribution pattern can be made clear. Here, the light-emitting portion is a portion that looks shining, and a light-emitting element is an example.

  According to the present invention, a light distribution pattern different from the shape of the light emitting surface of the light emitting part can be formed.

FIG. 1A is a perspective view schematically showing a schematic structure of a lamp unit according to the present embodiment as viewed from the front, and FIG. 1B is a view of the lamp unit according to the present embodiment as viewed from the rear. It is a perspective view which shows a schematic structure typically. FIG. 2A is a top view schematically showing the schematic structure of the lamp unit according to the present embodiment, and FIG. 2B is a side view schematically showing the schematic structure of the lamp unit according to the present embodiment. FIG. It is a front view which shows typically the schematic structure of the lamp unit which concerns on this Embodiment. FIG. 4A is a diagram showing a ray diagram in a vertical section including the optical axis of the projection lens according to the present embodiment, and FIG. 4B includes the optical axis of the projection lens according to the present embodiment. It is the figure which showed the light ray figure in a horizontal cross section. It is a front view of the LED array which is an example of the light source which concerns on this Embodiment. It is a figure which shows the light distribution pattern by the LED array of the lighting-off state shown in FIG.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, members, and processes shown in the drawings are denoted by the same reference numerals, and repeated descriptions are omitted as appropriate. Further, the embodiments do not limit the invention but are exemplifications, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

  FIG. 1A is a perspective view schematically showing a schematic structure of a lamp unit according to the present embodiment as viewed from the front, and FIG. 1B is a view of the lamp unit according to the present embodiment as viewed from the rear. It is a perspective view which shows a schematic structure typically. FIG. 2A is a top view schematically showing the schematic structure of the lamp unit according to the present embodiment, and FIG. 2B is a side view schematically showing the schematic structure of the lamp unit according to the present embodiment. FIG. FIG. 3 is a front view schematically showing a schematic structure of the lamp unit according to the present embodiment.

  The lamp unit 10 according to the present embodiment is mainly used for a vehicle lamp (for example, a vehicle headlamp). As shown in each drawing, the lamp unit 10 includes a projection lens 12, a light source mounting portion 14 disposed near the focal point of the projection lens 12, and a light source 16 as a light emitting portion mounted on the light source mounting portion 14. . Here, the light emitting portion is a bright portion from which light is emitted, and a light source is an example.

  The projection lens 12 includes a rectangular lens body 12a in which the length in the horizontal direction H is longer than the length in the vertical direction V in front view from the front shown in FIG. 3, and the projection lens 12 is a lamp for a vehicle headlamp. And an attachment portion 12b for fixing in the room. The projection lens 12 is formed by integral molding using a transparent resin or the like.

  Moreover, it has the incident surface 12c into which the light radiate | emitted from the light source 16 injects, and the output surface 12d in which the light incident from the incident surface 12c radiate | emits toward the front of a lamp. The incident surface 12c of the projection lens 12 is convex toward the front. The exit surface 12d of the projection lens 12 is convex toward the front.

  The light source mounting unit 14 is configured so that the light source 16 can be mounted at a desired position. For example, the light source mounting unit 14 may also serve as a heat radiating member (heat sink) for releasing heat generated by the light source 16 to the outside of the unit.

  4A is a diagram showing a light ray diagram in a vertical section including the optical axis of the projection lens 12 according to the present embodiment, and FIG. 4B is an optical axis of the projection lens 12 according to the present embodiment. It is the figure which showed the light ray figure in the horizontal cross section containing.

  The entrance surface 12c and the exit surface 12d are configured such that the horizontal plane focal length Fh with respect to the rear focal point F in the horizontal section including the optical axis is different from the vertical plane focal length Fv with respect to the rear focal point F in the vertical section including the optical axis. .

  According to this aspect, a light distribution pattern different from the shape of the light emitting surface of the light source near the focal point F can be formed. Here, the light emitting surface is, for example, a portion that looks bright when viewed from the front. In addition, the projection lens 12 can project a light distribution pattern in which the aspect ratio is changed while maintaining the luminous intensity distribution of the light emitting surface of the light source 16.

  The entrance surface 12c and the exit surface 12d according to the present embodiment are configured to satisfy Fv> 1.2 × Fh. As a result, a light distribution pattern having a large horizontal expansion rate can be realized.

  Furthermore, the light source image can be formed more clearly by configuring the shape of the projection lens 12 in the lamp unit 10 in consideration of the following sine condition.

As shown in FIG. 4A, in the vertical cross section including the optical axis Ax, the projection lens 12 sets the emission angle of the light beam L (for example, L1, L2) emitted from the rear focal point F with respect to the optical axis Ax to θ (θ1). , Θ2), where h (h1, h2) is the distance between the light beam L emitted from the projection lens 12 and the optical axis Ax,
0.9 × | h | <Fv × sin θ <1.1 × | h | Expression (1)
It is configured to satisfy. More preferably,
| H | ≈Fv × sin θ (2)
It is good to be comprised so that it may satisfy | fill.

Further, as shown in FIG. 4B, in the horizontal section including the optical axis Ax, the projection lens 12 sets the emission angle of the light beam L (for example, L3, L4) emitted from the rear focal point F to the optical axis Ax as θ. (Θ3, θ4), where h (h3, h4) is the distance between the light beam L emitted from the projection lens 12 and the optical axis Ax,
0.9 × | h | <Fh × sin θ <1.1 × | h |
It is configured to satisfy. More preferably,
| H | ≈Fh × sin θ (4)
It is good to be comprised so that it may satisfy | fill.

  By configuring the shape of the projection lens 12 so as to satisfy Expression (1) and Expression (3), and more preferably, Expression (2) and Expression (4), an object near the focal point (for example, The light-emitting surface of the light source can be clearly imaged. In order to obtain the projection lens 12 having such a shape, in the present embodiment, the entrance surface 12c and the exit surface 12d are configured by free-form surfaces.

  Moreover, the lamp unit 10 according to the present embodiment can form a low beam light distribution pattern having a cut-off line by including a light shielding member.

  The light source 16 included in the lamp unit 10 may be a flat light source, a cylindrical light source, or a unit that combines a flat light source and a compound parabolic concentrator that collects the light. Examples of the light emitting element used for the light source include an LED element, an LD element, and an EL element.

  In addition, the light source 16 may be an LED array in which a plurality of light emitting elements that can be turned on and off independently are arranged, for example, an LED array. FIG. 5 is a front view of an LED array which is an example of a light source according to the present embodiment. The LED array 18 includes a plurality of LED chips 20 that can be turned on and off independently and arranged in an array. Specifically, the LED array 18 has 16 LED chips 20 arranged in a row in the horizontal direction.

  The LED array 18 can turn off a part of the light distribution pattern by using the LED chip 20a that has been turned on and the LED chip 20b that has been turned off. Can be suppressed.

  FIG. 6 is a diagram showing a light distribution pattern by the LED array 18 in the on / off state shown in FIG. The LED chip 20 has a square light-emitting surface, but by using the projection lens 12, as shown in FIG. 6, the light source image of the lit LED chip 20a is stretched and projected in the horizontal direction. I understand that. That is, a light distribution pattern different from the shape of the light emitting surface of the LED array 18 as a light source (different in aspect ratio) can be formed relatively clearly. In addition, a part of the light distribution pattern can be non-irradiated (shielded).

  In addition, since the light source image of the LED array 18 can be extended in the horizontal direction by the projection lens 12, the number of LED chips necessary for forming a predetermined light distribution pattern can be reduced.

  As described above, the lamp unit 10 according to the present embodiment includes the projection lens 12 and the light source 16 disposed in the vicinity of the rear focal point F of the projection lens 12. The light source 16 has a plurality of LED chips 20 arranged in an array, and is configured such that a part of the LED chips 20b of the plurality of LED chips 20 can be turned off when turned on. Since the projection lens 12 according to the present embodiment is configured in consideration of the above-described sine condition, even when part of the LED chip 20 is turned off, the irradiation unit and the non-irradiation unit in the light distribution pattern The bright and dark borders can be sharpened.

  In other words, the lamp unit 10 may be a so-called ADB (Adaptive Driving Beam) that changes the irradiation state of a partial area of the high beam light distribution pattern by turning off some of the LED chips 20b of the LED array 18. Available.

  As described above, the present invention has been described with reference to the above-described embodiment. However, the present invention is not limited to the above-described embodiment, and the present invention can be appropriately combined or replaced with the configuration of the embodiment. It is included in the present invention. Further, based on the knowledge of those skilled in the art, it is possible to appropriately change the combination and processing order in each embodiment and to add various modifications such as various design changes to the embodiment. Added embodiments may be included in the scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 Lamp unit, 12 Projection lens, 12a Lens main body, 12c Incident surface, 12d Output surface, 14 Light source mounting part, 16 Light source, 18 LED array, 20 LED chip

Claims (5)

A projection lens used in a vehicular lamp,
An incident surface on which light emitted from the light emitting portion is incident;
An exit surface from which light incident from the entrance surface exits toward the front of the lamp, and
The entrance surface and the exit surface are
A projection lens configured such that a horizontal focal length Fh with respect to a rear focal point in a horizontal section including an optical axis is different from a vertical focal length Fv with respect to a rear focal point in a vertical section including an optical axis. The entrance surface and the exit surface are
The exit angle with respect to the optical axis of the light beam emitted from the back focal point is θ,
When the distance between the light beam emitted from the projection lens and the optical axis is h,
0.9 × | h | <Fv × sin θ <1.1 × | h |
0.9 × | h | <Fh × sin θ <1.1 × | h |
The projection lens according to claim 1, wherein the projection lens is configured to satisfy the following. The entrance surface and the exit surface are
The projection lens according to claim 1, wherein the projection lens is configured to satisfy Fv> 1.2 × Fh.   The projection lens according to claim 1, wherein the entrance surface and the exit surface are free-form surfaces. A projection lens according to any one of claims 1 to 4,
A light emitting portion disposed in the vicinity of the rear focal point of the projection lens,
The light emitting unit includes a plurality of light emitting units arranged in an array, and is configured to be capable of turning off some of the light emitting units when the light is turned on.