Lighting unit

Abstract

To provide a new lightweight lamp fixture.SOLUTION: A lamp fixture unit comprises a light emitting element with a light emitting surface 40b facing a front face of a vehicle lamp, and a Fresnel lens 38 having an incident surface 38a facing the light emitting surface 40b. The Fresnel lens 38 has: a condensing lens part 38b that is positioned at a front face of the light emitting surface 40b; and diffusion lens parts 38c, 38d that are provided below the condensing lens part 38b, and on which light L1, L2 emitted diagonally downward from the light emitting surface 40b is made incident. The diffusion lens parts 38c, 38d are configured so that the light refracted by a light condensing / emitting surface 39b of the condensing lens part 38b and discontinuous diffusing / emitting surfaces 39c, 39d is emitted toward the front face of the vehicle lamp.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a lighting unit, for example, a lighting unit used in a vehicle lamp. [Background technology]

[0002] Conventionally, a lighting unit has been devised that includes a light-emitting element array in which a plurality of light-emitting elements configured to be individually lit, each having an individual irradiation area that constitutes a high-beam light distribution pattern, are mounted in a row on a substrate, a projection lens arranged in front of the light-emitting element array, and a reflector arranged below the light-emitting element array (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 16 / 013447 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] However, the reflectors used in the above-mentioned lamp units are often made of metal for heat resistance, which tends to make them heavy. Also, in order to reflect more of the light emitted downward from the light-emitting element, the reflector needs to be extended in depth, which increases the thickness of the lamp unit in the longitudinal direction of the vehicle.

[0005] The present invention has been made in view of the above circumstances, and one of its exemplary purposes is to provide a new lighting unit that is lightweight while realizing a desired light distribution. [Means for solving the problem]

[0006] In order to solve the above problems, a lighting unit according to one aspect of the present invention includes a light-emitting element having a light-emitting surface facing the front of the vehicle lamp, and a Fresnel lens having an incident surface opposite the light-emitting surface. The Fresnel lens has a condensing lens portion for condensing light located in front of the light-emitting surface, and a diffusing lens portion for diffusing light that is provided below the condensing lens portion and onto which light emitted obliquely downward from the light-emitting surface is incident. The diffusing lens portion is configured so that light refracted at a diffusing exit surface that is discontinuous with the condensing exit surface of the condensing lens portion is emitted toward the front of the vehicle lamp.

[0007] According to this aspect, light emitted obliquely downward from the light-emitting surface of the light-emitting element can be directed toward the front of the vehicle lamp by being refracted by the diffusion lens portion. Therefore, the thickness of the optical member (Fresnel lens) required for light distribution control in the longitudinal direction of the vehicle can be reduced compared to when light emitted obliquely downward from the light-emitting surface of the light-emitting element is reflected by a reflector and directed toward the front of the vehicle lamp. Furthermore, the Fresnel lens can be made of a resin lens made of silicone, which allows for a lighter lamp unit compared to when a metal reflector is used.

[0008] The vehicle lamp may further include a projection lens that projects the light emitted from the Fresnel lens as a light distribution pattern in front of the vehicle lamp. The diffusing lens portion may be configured so that the emitted light illuminates an upper range of the light distribution pattern. This allows the illumination area of ​​a light distribution pattern that illuminates above the horizon, such as a high-beam light distribution pattern, to be further expanded.

[0009] The projection lens may be configured so that the light emitted from the Fresnel lens does not reflect off other components, but instead travels a short optical path to reach the projection lens, improving the efficiency of light utilization from the light-emitting element.

[0010] The diffusing lens portion may include a first diffusing lens portion located below the condensing lens portion and having an exit surface located forward of the tip of the condensing lens portion, and a second diffusing lens portion located below the first diffusing lens portion and having an exit surface located forward of the first diffusing lens portion. This allows the thickness of the entire Fresnel lens to be reduced, while utilizing the light emitted obliquely downward from the light-emitting surface of the light-emitting element to be diffused upward in the illumination area of ​​the light distribution pattern.

[0011] The second diffusing lens portion may be configured to emit light that illuminates an area 6 to 8 degrees above the horizontal line of the high beam light distribution pattern.

[0012] Any combination of the above components, and conversion of the present invention between a manufacturing method, a lighting fixture or lighting device, a light emitting module, a light source, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0013] According to the present invention, a new light-weight lamp unit can be realized. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a schematic front view of a vehicle headlamp according to an embodiment of the present invention; [Figure 2] 2 is a schematic cross-sectional view of the vehicle headlamp of FIG. 1 taken along a horizontal plane passing through line AA in FIG. 1. [Figure 3] 3(a) is a cross-sectional view of the high beam lamp unit taken along a vertical plane passing through line BB in FIG. 2, and FIG. 3(b) is an enlarged view of part C in FIG. 3(a). [Figure 4] FIG. 4(a) is a front view of the Fresnel lens according to the present embodiment, and FIG. 4(b) is a perspective view of the Fresnel lens according to the present embodiment. [Figure 5] 1 is a cross-sectional view showing a main configuration of a high beam lamp unit according to an embodiment of the present invention. [Figure 6]5A and 5B are diagrams illustrating an example of a high beam light distribution pattern formed by a high beam lamp unit. DETAILED DESCRIPTION OF THE INVENTION

[0015] The present invention will be described below based on preferred embodiments with reference to the drawings. The same or equivalent components, parts, and processes shown in each drawing will be given the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, the embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0016] Fig. 1 is a schematic front view of a vehicle headlamp 10 according to this embodiment. Fig. 2 is a schematic cross-sectional view of the vehicle headlamp 10 of Fig. 1 taken along a horizontal plane passing through line AA in Fig. 1. The vehicle headlamp 10 is equipped with a left lamp and a right lamp on each of the left and right sides of the front of the vehicle body, but Fig. 1 shows only the right lamp. The left lamp has the same configuration as the right lamp except that it is symmetrical, so it is not shown in the figure.

[0017] The vehicle headlamp 10 has a lamp chamber 11 formed by a lamp body 18 (see FIG. 2) with an opening facing forward of the vehicle and a transparent or translucent outer cover 16 that covers the opening of the lamp body. A low beam lamp unit 12 and a high beam lamp unit 14 are arranged inside the lamp chamber 11.

[0018] The low beam lamp unit 12 and the high beam lamp unit 14 are fixed on a common support plate 20. The support plate 20 is fixed to the lamp body 18 by a plurality of (for example, three) aiming screws 48. By rotating the aiming screws 48, it is possible to adjust the optical axis O of the low beam lamp unit 12 and the high beam lamp unit 14 so that the optical axis O is tilted within a predetermined angle range.

[0019] The low beam lamp unit 12 is a so-called PES type lamp unit and includes, on the front side of a support plate 20, a projection lens 22, a lens holder 24 that supports the projection lens 22, a light-emitting element array 28 consisting of a plurality of semiconductor light-emitting elements such as LEDs (Light Emitting Diodes), and a reflector 26 that reflects light from the light-emitting element array 28 toward the projection lens 22. The low beam lamp unit 12 further includes a heat sink 30 with heat dissipation fins attached to the back side of the support plate 20, and a cooling fan 32.

[0020] Fig. 3(a) is a cross-sectional view of the high beam lamp unit 14 taken along a vertical plane passing through line BB in Fig. 2, and Fig. 3(b) is an enlarged view of part C in Fig. 3(a). The high beam lamp unit 14 will be described below with reference to Figs. 2 and 3.

[0021] The high beam lamp unit 14 is a lamp unit that can change its light distribution pattern depending on the driving conditions of the vehicle and the surrounding conditions. The high beam lamp unit 14 includes a projection lens 34, a lens holder 36, a Fresnel lens 38, and a light emitting element array 40.

[0022] The projection lens 34 is a plano-convex aspherical lens with a convex front surface and a flat rear surface, and projects the light source image formed on its rear focal plane as an inverted image onto a virtual vertical screen in front of the lamp. The projection lens 34 is attached to one opening of a cylindrical lens holder 36.

[0023] The light-emitting element array 40 is composed of one or more (12 in this embodiment) semiconductor light-emitting elements 40a mounted on a substrate 41. Each semiconductor light-emitting element 40a has the same shape and is arranged in a line on the surface of the substrate 41 with its light-emitting surface facing the front of the vehicle headlamp 10. Each light-emitting element can be turned on and off individually, and is configured to be able to respectively illuminate individual illumination areas that divide the high-beam light distribution pattern in the horizontal direction. It is preferable that the individual illumination area of ​​each light-emitting element at least partially overlaps with the individual illumination area of ​​an adjacent light-emitting element.

[0024] Each semiconductor light-emitting element 40a has a light-emitting chip (not shown) and a thin film. The light-emitting chip is, for example, a white light-emitting diode having a square light-emitting surface of about 1 mm on each side. The light-emitting chip is not limited to this, and may be other element-like light sources that emit light in a substantially point-like surface, such as laser diodes. The rear focal point F of the projection lens 34 may be located on the surface of the semiconductor light-emitting element 40a, or may be located further forward as described below.

[0025] A Fresnel lens 38 is disposed in front of the light emitting element array 40. As shown in Fig. 3(b), the Fresnel lens 38 has an incident surface 38a that faces the light emitting surface 40b of the semiconductor light emitting element 40a.

[0026] As shown in FIG. 3( b ), a light blocking plate 42 that blocks part of the light emitted from the light emitting element array 40 is provided in front of the light emitting element array 40 .

[0027] A control unit 49 for controlling the on / off of the light-emitting element array 40 is disposed on the bottom surface of the lamp body 18. The control unit 49 detects the positions of preceding vehicles and pedestrians using a camera (not shown), and controls the light-emitting element array 40 so as not to illuminate the individual illumination areas corresponding to those positions, thereby realizing an ADB (Adaptive Driving Beam) that does not give glare to the driver of the preceding vehicle or pedestrians.

[0028] The high beam lamp unit 14 further includes a heat sink 44 with heat dissipation fins attached to the rear side of the support plate 20, and a cooling fan 46.

[0029] Resin extensions 50, 52, 54 are arranged in the lamp chamber 11 so as to cover gaps formed between the low beam lamp unit 12, the high beam lamp unit 14, and the lamp body 18, and hide the internal structure when the vehicle headlamp 10 is observed from the front.

[0030] Fig. 4(a) is a front view of the Fresnel lens according to this embodiment, and Fig. 4(b) is a perspective view of the Fresnel lens according to this embodiment. Fig. 5 is a cross-sectional view showing the main configuration of high beam lamp unit 14 according to this embodiment.

[0031] As shown in FIG. 5, the high beam lamp unit 14 includes a semiconductor light-emitting element 40a whose light-emitting surface 40b faces the front of the vehicle headlamp 10, a Fresnel lens 38 having an incident surface 38a facing the light-emitting surface 40b, and a projection lens 34 that projects the light emitted from the Fresnel lens 38 as a light distribution pattern onto the front of the vehicle lamp.

[0032] The Fresnel lens 38 includes a condensing lens portion 38b for condensing light located in front of the light-emitting surface 40b, a diffusing lens portion 38c for diffusing light that is provided below the condensing lens portion 38b and onto which light L1 emitted obliquely downward from the light-emitting surface 40b is incident, and a diffusing lens portion 38d for diffusing light that is emitted from the light-emitting surface 40b at an even more oblique downward angle than light L1 is incident. The diffusing lens portions 38c and 38d are configured so that light refracted at the diffusing emission surfaces 39c and 39d, which are discontinuous with the condensing emission surface 39b of the condensing lens portion 38b, is emitted toward the front of the high beam lamp unit 14.

[0033] As shown in Figures 4(a) and 4(b), the Fresnel lens 38 is composed of 12 condensing lens portions 38b and 12 pairs of diffusing lens portions 38c, 38d corresponding to the 12 semiconductor light-emitting elements 40a, respectively.

[0034] As a result, the high beam lamp unit 14 can direct the light L1, L2 emitted obliquely downward from the light-emitting surface 40b of the semiconductor light-emitting element 40a toward the front of the vehicle headlamp 10 by refracting the light at the diffusion lens portions 38c, 38d. Therefore, the thickness of the Fresnel lens 38 in the vehicle fore-and-aft direction (X direction) required for light distribution control can be reduced compared to when the light L1, L2 emitted obliquely downward from the light-emitting surface 40b of the semiconductor light-emitting element 40a is reflected by a reflector and directed toward the front of the vehicle lamp. In addition, the Fresnel lens 38 can be made of a resin lens made of silicone, which allows the high beam lamp unit 14 to be made lighter than when a metal reflector is used.

[0035] 6 is a diagram showing an example of a high beam light distribution pattern formed by the high beam lamp unit 14. The diffusion lens portions 38c and 38d are configured so that the emitted light irradiates an upper range R1 of the high beam light distribution pattern PH. This makes it possible to further expand the illumination area of ​​a light distribution pattern that irradiates above the horizon, such as a high beam light distribution pattern.

[0036] In addition, light L3 emitted obliquely upward from light-emitting surface 40b is refracted by condenser lens portion 38b and further refracted by projection lens 34, thereby irradiating lower range R2 of high-beam light distribution pattern PH. This makes it possible to illuminate the road surface, which is the area below the horizon, in a light distribution pattern that mainly irradiates areas above the horizon, such as a high-beam light distribution pattern.

[0037] The projection lens 34 according to this embodiment is disposed at a position where the light emitted from the Fresnel lens 38 is incident without being reflected by other components, in other words, at a position where the light emitted from the Fresnel lens 38 is directly incident. This allows the light emitted from the Fresnel lens 38 to reach the projection lens 34 via a short optical path without being reflected along the way or passing through other components, thereby improving the light utilization efficiency of the semiconductor light emitting element 40a.

[0038] The diffusing lens portion according to the present embodiment includes a diffusing lens portion 38c that is located below the condensing lens portion 38b and has a diffused emission surface 39c positioned forward of the tip of the condensing lens portion 38b, and a diffusing lens portion 38d that is located below the diffusing lens portion 38c and has a diffused emission surface 39d positioned forward of the diffusing lens portion 38c. This allows the overall thickness of the Fresnel lens 38 to be reduced while utilizing the light emitted obliquely downward from the light-emitting surface 40b of the semiconductor light-emitting element 40a to be diffused upward in the illumination area of ​​the high-beam light distribution pattern PH.

[0039] In particular, the diffusion lens portion 38d is configured to emit light that illuminates an area of ​​the high-beam light distribution pattern PH that is 6 to 8 degrees above the horizontal. Alternatively, the diffusion lens portion 38d may be configured to emit light that illuminates an area of ​​the high-beam light distribution pattern PH that is 6 degrees or more above the horizontal, preferably 8 degrees or more above the horizontal. Furthermore, since the diffusion exit surface 39d of the diffusion lens portion 38d is located further forward than the diffusion lens portion 38c, the luminous intensity of the upper range R1 of the high-beam light distribution pattern PH can be further increased and the utilization rate of the light emitted from the semiconductor light-emitting element 40a can be improved.

[0040] Moreover, the high beam light distribution pattern PH according to this embodiment is formed by projecting transmitted light (refracted light) that has passed through the Fresnel lens 38, out of the light emitted from the light-emitting element array 40, to the front of the vehicle by the projection lens 34. Therefore, it is possible to reduce unevenness in brightness within the light distribution pattern compared to a light distribution pattern in which direct light and reflected light are mixed, as occurs when a reflector is used.

[0041] The light-emitting surface 40b of the semiconductor light-emitting element 40a according to this embodiment may be rectangular with sides of approximately 0.8 to 2.0 mm. The distance between the light-emitting surface 40b of the semiconductor light-emitting element 40a and the incident surface 38a of the Fresnel lens 38 is very short, approximately 0.5 to 1.5 mm. Therefore, the Fresnel lens 38 is preferably made of a material that takes into consideration heat resistance and moldability, such as silicone or glass. The Fresnel lens 38 has a thickness in the Z direction of approximately 5 to 10 mm, and the condenser lens portion 38b has a thickness in the Z direction of approximately 2 to 5 mm. The projection lens 34 has a thickness in the Z direction of approximately 20 to 30 mm. The distance between the light-emitting surface 40b of the semiconductor light-emitting element 40a and the incident surface 34a of the projection lens 34 is approximately 20 to 40 mm.

[0042] Although the present invention has been described above with reference to the above-mentioned embodiments, the present invention is not limited to the above-mentioned embodiments, and suitable combinations and substitutions of the configurations of the embodiments are also included in the present invention. Furthermore, it is possible to suitably rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to make modifications to the embodiments such as various design changes, and such modified embodiments are also included in the scope of the present invention. [Explanation of symbols]

[0043] 10 Vehicle headlamp, 14 High beam lamp unit, 34 Projection lens, 34a Incident surface, 38 Fresnel lens, 38a Incident surface, 38b Condenser lens section, 38c Diffused lens section, 38d Diffused lens section, 39b Condenser exit surface, 39c Diffused exit surface, 39d Diffused exit surface, 40 Light-emitting element array, 40a Semiconductor light-emitting element, 40b Light-emitting surface, R1 Upper range, R2 Lower range, PH High beam light distribution pattern.

Claims

1. a light-emitting element whose light-emitting surface faces the front of the vehicle lamp; a Fresnel lens having an incident surface facing the light emitting surface, The Fresnel lens is a condenser lens portion for condensing light located in front of the light emitting surface; a diffusion lens portion for diffusing light that is provided below the condensing lens portion and onto which light that is obliquely emitted downward from the light emitting surface is incident, the diffusing lens portion is configured so that light refracted at a diffusing exit surface that is discontinuous with the light collecting exit surface of the light collecting lens portion is emitted toward a front surface of the vehicle lamp, The diffusing lens portion is a first diffusing lens portion located below the condensing lens portion and having an exit surface located forward of a tip of the condensing lens portion; a second diffusing lens portion located below the first diffusing lens portion and having an exit surface located forward of the first diffusing lens portion; A lighting unit comprising:

2. The vehicle lamp further includes a projection lens that projects the light emitted from the Fresnel lens onto a front surface of the vehicle lamp as a light distribution pattern, 2. The lamp unit according to claim 1, wherein the diffusing lens portion is configured so that the emitted light illuminates an upper range of the light distribution pattern.

3. 3. The lamp unit according to claim 2, wherein the light emitted from the Fresnel lens is incident on the projection lens without being reflected by other members.

4. The lamp unit according to any one of claims 1 to 3, characterized in that the second diffusing lens portion is configured to emit light that illuminates an area 6 to 8 degrees above the horizontal line of the high beam light distribution pattern.

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