Lenses and vehicle lighting fixtures

Abstract

To provide a lens and a vehicle light fixture that can suppress thermoplastic deformation at the corners. [Solution] The lens (60) has a light incident section and a light outgoing section, the light outgoing section has a Fresnel surface in which multiple refractive surfaces (62a to 62c) are arranged in a stepped manner, and the material constituting the surface of the Fresnel surface is a lens (60) with a higher thermal distortion temperature than the material constituting the light incident section.

Description

Technical Field

[0001] The present invention relates to a lens and a vehicular lamp.

Background Art

[0002] As vehicular lamps such as headlamps, a projector type has been proposed which uses an LED (Light Emitting Diode) as a light source, reflects light from the light source with a reflector, and adjusts light distribution with a lens. In such a projector-type vehicular lamp, since light is refracted by the lens to limit the light irradiation range, the lens tends to be thick-walled, making miniaturization and weight reduction difficult. Accordingly, to reduce the thickness and weight of the lens, a projector-type vehicular lamp using a Fresnel lens has also been proposed (see, for example, Patent Documents 1 to 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of Invention

Problems to be Solved by the Invention

[0004] In a Fresnel lens, a refraction surface for achieving desired optical characteristics is divided into a plurality of cross-sectional regions, and a plurality of curved surfaces are arranged in a stepped manner, so that the curved surfaces are discontinuous at the stepped portions. Further, in order to improve the optical characteristics of the Fresnel lens, it is necessary to form the corner portions of the curved surfaces and the cross sections to be sharp. However, the inventors of the present application have found a problem that when a Fresnel lens is used in a vehicular lamp, since the amount of light required for the vehicular lamp is large, thermoplastic deformation occurs at the corner portions of the Fresnel lens, leading to deterioration of the optical characteristics.

[0005] Therefore, the present invention has been made in view of the above-mentioned conventional problems, and aims to provide a lens and a vehicle light fixture that can suppress thermoplastic deformation at the corners. [Means for solving the problem]

[0006] To solve the above problems, the lens of the present invention has a light incident portion and a light output portion, wherein the light output portion has a Fresnel surface in which a plurality of refractive surfaces are arranged in a stepped manner, and the material constituting the surface of the Fresnel surface has a higher thermal distortion temperature than the material constituting the light incident portion.

[0007] In the lens of the present invention, the material constituting the surface of the Fresnel surface has a higher thermal deformation temperature than the material constituting the light incident portion, thereby making it possible to suppress thermoplastic deformation at the corners.

[0008] Furthermore, in one aspect of the present invention, there is a holding portion having the light incident portion and a Fresnel portion having the light emission portion, wherein the material constituting the surface of the Fresnel portion has a higher thermal distortion temperature than the material constituting the holding portion.

[0009] In another aspect of the present invention, the Fresnel portion is made of silicone resin.

[0010] In another aspect of the present invention, the Fresnel portion is provided with an engaging portion that engages with the holding portion.

[0011] In another aspect of the present invention, the light incident portion and the Fresnel portion are integrally constructed from the same material, and a coating layer made of an inorganic material is formed on the surface of the Fresnel lens portion.

[0012] In another aspect of the present invention, the coating layer has a film thickness in the range of 100 nm to 300 nm.

[0013] In another aspect of the present invention, the coating layer is composed of SiO2 or MgF2.

[0014] To solve the above problems, the vehicle lighting device of the present invention is characterized by comprising a lens as described in any one of the above embodiments, a light source that emits light, and a reflecting part that reflects light from the light source. [Effects of the Invention]

[0015] The present invention provides a lens and a vehicle lamp that can suppress thermoplastic deformation at the corners. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic cross-sectional view showing an example of the configuration of a vehicle lighting device 100 using the lens 60 according to the first embodiment. [Figure 2] Figure 2(a) is a schematic plan view and Figure 2(b) is a schematic cross-sectional view illustrating the configuration of the lens 60 according to the first embodiment. [Figure 3] This is a schematic cross-sectional view illustrating the configuration of the lens 60 according to the second embodiment. [Figure 4] This is a schematic cross-sectional view illustrating the configuration of the lens 60 according to the third embodiment. [Modes for carrying out the invention]

[0017] (First Embodiment) Embodiments of the present invention will be described in detail below with reference to the drawings. The same or equivalent components, members, and processes shown in each drawing will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. Figure 1 is a schematic cross-sectional view showing an example of the configuration of a vehicle lamp 100 using the lens 60 according to this embodiment. As shown in Figure 1, the vehicle lamp 100 is a projector-type lamp unit and comprises a support member 10, a light source 20, a reflector 30, a shade part 40, a lens holding part 50, and a lens 60. The dashed line in Figure 1 schematically shows the path of light emitted from the light source 20.

[0018] The support member 10 is a member that holds the light source 20, the reflector 30, the shade portion 40, and the lens holding portion 50. The material constituting the support member 10 is not limited, but in order to satisfactorily dissipate the heat generated by the light source 20, it is preferable to use a metal material such as aluminum. Although a rectangular cross-section is shown as the support member 10 in FIG. 1, a plurality of heat dissipation fins may be provided upright on the back surface side of the plate-shaped member. On the upper surface of the support member 10, the light source 20 is mounted on a surface facing upward in the direction perpendicular to the light irradiation direction.

[0019] The light source 20 is, for example, a light emitting diode (LED), and is a member that emits light when supplied with electric power and a control signal. Although not illustrated in FIG. 1, the light source 20 is mounted on a substrate, and electric power is supplied thereto via wiring with electronic components formed on the substrate. Examples of the position where the light source 20 is arranged include the vicinity of the focal position of the reflector 30.

[0020] The reflector 30 is provided on the support member 10 so as to cover the light source 20, and is a member that reflects light from the light source 20. The shape of the reflector 30 is not limited, but in the example shown in FIG. 1, the reflector 30 has a reflective surface on the inner side that is constituted by a free-form surface based on a spheroidal surface. This reflective surface has a first focal point. In the reflector 30, the light source 20 is positioned in the vicinity of the first focal point of the reflector 30. Further, a shade portion 40 is provided in the vicinity of the second focal point of the reflector 30. The reflector 30 corresponds to the reflecting portion in the present invention.

[0021] The shade portion 40 is the part that reflects a portion of the light reflected by the reflector 30. Figure 1 shows an example in which the shade portion 40 and the support member 10 are constructed as separate parts, but a part of the support member 10 may also be used as the shade portion 40. In the example shown in Figure 1, the shade portion 40 has a planar portion that is positioned approximately horizontally and a curved portion that curves downward on the front side of the lamp compared to the planar portion, and the boundary between the planar portion and the curved portion forms a ridge. A portion of the light reflected by the reflector 30 is reflected by the shade portion 40, so that the ridge of the shade portion 40 forms a cutoff line for the light projected from the vehicle lamp 100.

[0022] The lens holding portion 50 is a part provided on the support member 10 that holds the lens 60. In the example shown in Figure 1, the support member 10 and the lens holding portion 50 are shown as separate components, but a part of the support member 10 may also be used as the lens holding portion 50. Also, although Figure 1 shows an example in which the lens holding portion 50 holds the lower end of the lens 60, the shape of the lens holding portion 50 and the position in which it holds the lens 60 are not limited.

[0023] The lens 60 is an optical component that refracts the light reflected by the reflector 30 to limit the range of light illumination. The lens 60 has a light incident surface, which is the surface into which light enters, and a light exit surface, which is the surface from which light exits. The light exit surface has a Fresnel surface in which multiple refractive surfaces are arranged in a stepped manner. Details of the lens 60 will be described later.

[0024] Light emitted from the light source 20 is reflected by the reflective surface of the reflector 30, passes near the edge of the shade portion 40, enters the light inlet of the lens 60, and is projected forward from the light emission portion. In addition, a portion of the light reflected by the reflector 30 is reflected by the flat portion of the shade portion 40 and selectively cut off with the edge as the boundary line. As a result, a light distribution pattern having a cutoff line corresponding to the shape of the edge is projected forward of the vehicle lamp 100.

[0025] Figure 2 is a schematic diagram illustrating the configuration of the lens 60 according to this embodiment, where Figure 2(a) is a schematic plan view and Figure 2(b) is a schematic cross-sectional view. As shown in Figure 2, the lens 60 has a holding portion 61, Fresnel portions 62a to 62c, and engaging portion 63. In the lens 60 of this embodiment, the holding portion 61 and the Fresnel portions 62a to 62c are made of different materials and are constructed as separate parts.

[0026] The holding portion 61 is provided on the light source 20 side of the lens 60 and is a substantially plate-shaped portion that holds the Fresnel portions 62a to 62c. The light source 20 side of the holding portion 61 is a planar light incident portion, and the Fresnel portions 62a to 62c are provided on the side opposite to the light source 20. In the example shown in Figure 2, an engagement groove is formed on the holding portion 61 at a position corresponding to the engagement portion 63. The thickness of the holding portion 61 is not limited, but in order to properly hold the Fresnel portions 62a to 62c, a range of 2 mm to 5 mm can be used, and more preferably a range of 2 mm to 3 mm.

[0027] The material constituting the holding portion 61 is not limited, but it is preferable that it transmits light from the light source 20 well and has the mechanical strength to hold the Fresnel portions 62a to 62c. Examples of materials constituting the holding portion 61 include polymethyl methacrylate (PMMA) and polycarbonate (PC). By using PMMA resin or PC resin, which have higher rigidity than the material constituting the Fresnel portions 62a to 62c, deformation of the Fresnel portions 62a to 62c can be suppressed and the optical properties can be maintained.

[0028] The Fresnel sections 62a to 62c are located on the light-emitting side of the lens 60 and are the parts that refract light. Each of the Fresnel sections 62a to 62c has a refractive surface, and the Fresnel surface is formed by the refractive surfaces of multiple Fresnel sections 62a to 62c. Each refractive surface of the Fresnel sections 62a to 62c is created by dividing a single hypothetical refractive surface into multiple cross-sectional regions and adjusting the thickness of each cross-sectional region to be approximately the same. The specific configuration of the Fresnel sections 62a to 62c is not limited, but as shown in Figure 2, a configuration in which the Fresnel sections 62a to 62c are arranged concentrically can be used.

[0029] Furthermore, although Figure 2 shows an example where the Fresnel portion 62a to 62c is divided into three regions, the number of regions constituting the Fresnel surface is not limited. Also, since the light distribution is controlled using the refraction of light in the Fresnel portion 62a to 62c, the width of each region is preferably 10 times the wavelength or more, and more preferably 10 μm or more. In addition, from the viewpoint of thinning and lightening the lens 60, it is preferable that the thickness of the Fresnel portion 62a to 62c be 1 mm or less. The Fresnel portion 62a to 62c can be formed integrally with the holding portion 61 using two-color molding technology. Alternatively, the Fresnel portion 62a to 62c and the holding portion 61 may be formed separately and then joined together using laser welding technology.

[0030] The material that constitutes at least the surface of the Fresnel sections 62a to 62c has a higher thermal distortion temperature than the material that constitutes the holding section 61. Therefore, in the lens 60, the material that constitutes the surface of the Fresnel surface has a higher thermal distortion temperature than the material that constitutes the light incident section. Furthermore, it is more preferable to construct the entire Fresnel sections 62a to 62c with a material that has a higher thermal distortion temperature than the material that constitutes the holding section 61.

[0031] One example of a material that constitutes the Fresnel sections 62a to 62c is silicone resin. The heat distortion temperature of PMMA resin is about 85 to 100°C, and the heat distortion temperature of PC resin is about 130 to 140°C, while the heat distortion temperature of silicone resin is about 150 to 200°C. Therefore, by constructing the Fresnel sections 62a to 62c from silicone resin, heat deformation at the corners of the Fresnel sections 62a to 62c can be suppressed. In addition, silicone resin has better shape-following properties at the corners during mold molding than PMMA resin and PC resin, which can improve the optical properties of the Fresnel sections 62a to 62c.

[0032] The engaging portion 63 is provided on the Fresnel portions 62a to 62c and engages the Fresnel portions 62a to 62c with the holding portion. In the example shown in Figure 2, the engaging portion 63 protrudes from the Fresnel portions 62a to 62c toward the holding portion 61, and is inserted into an engagement groove formed in the holding portion 61 to engage it, but its shape and structure are not limited. Also, Figure 2 shows an example in which the engaging portion 63 is provided in the area where the holding portion 61 and the Fresnel portions 62a to 62c are in contact, but the position of the engaging portion 63 is not limited and may be provided along the outer circumference of the holding portion 61. Furthermore, when the holding portion 61 and the Fresnel portions 62a to 62c are integrally formed using two-color molding technology or laser welding technology, the Fresnel portions 62a to 62c are held by the entire contact surface between the two, so the engaging portion 63 may be omitted.

[0033] As described above, in the lens 60 and vehicle lamp 100 of this embodiment, the material constituting the surface of the Fresnel surface has a higher thermal distortion temperature than the material constituting the light incident portion, thus suppressing thermoplastic deformation at the corners.

[0034] (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to Figure 3. Content that overlaps with the first embodiment will be omitted from the explanation. Figure 3 is a schematic cross-sectional view illustrating the configuration of the lens 60 according to this embodiment. As shown in Figure 3, the lens 60 has a holding portion 61, Fresnel portions 62a to 62c, and an engaging portion 63. The holding portion 61 is also provided with an adjustment portion 61a. In this embodiment as well, the holding portion 61 and the Fresnel portions 62a to 62c are made of different materials and are constructed as separate parts. In the first embodiment, a flat plate-shaped example was shown for the holding portion 61, but in this embodiment, the holding portion 61 is not flat and is provided with an adjustment portion 61a.

[0035] The adjustment portion 61a is a curved portion provided on the surface of the holding portion 61 that contacts the Fresnel portions 62a to 62c. In the example shown in Figure 3, the curved shape of the adjustment portion 61a matches the refractive surface of the Fresnel portion 62a, but the region and shape of the adjustment portion 61a are not limited.

[0036] As shown in Figure 3, the adjustment section 61a allows the thickness of the Fresnel sections 62a to 62c to be adjusted independently of the shape of the refractive surface. This allows the thickness of each Fresnel section 62a to 62c to be set within an appropriate range, thereby suppressing deformation of the shape of the refractive surface. Furthermore, the difference in refractive index between the Fresnel sections 62a to 62c of the adjustment section 61a allows light to be refracted at the interface between them, improving the degree of freedom of the optical properties.

[0037] As described above, in the lens 60 and vehicle lamp 100 of this embodiment, the material constituting the surface of the Fresnel surface has a higher thermal distortion temperature than the material constituting the light incident portion, thus suppressing thermoplastic deformation at the corners.

[0038] (Third embodiment) Next, a third embodiment of the present invention will be described with reference to Figure 4. Details that overlap with the first embodiment will be omitted. Figure 4 is a schematic cross-sectional view illustrating the configuration of the lens 60 according to this embodiment. As shown in Figure 4, the lens 60 has a holding portion 61, Fresnel portions 62a to 62c, and a coating layer 64. This embodiment differs from the first embodiment in that the holding portion 61 and the Fresnel portions 62a to 62c are integrally formed from the same material.

[0039] As shown in Figure 4, the holding portion 61 and the Fresnel portions 62a to 62c are integrally constructed from the same material. Each of the Fresnel portions 62a to 62c has a refractive surface, and the Fresnel surface is formed by the refractive surfaces of multiple Fresnel portions 62a to 62c. The material constituting the holding portion 61 and the Fresnel portions 62a to 62c is not limited, but PMMA resin or PC resin can be used.

[0040] The coating layer 64 is a layer made of inorganic material that covers the surface (refractive surface) of the Fresnel sections 62a to 62c. The material used for the coating layer 64 has a higher thermal distortion temperature than the material used for the holding section 61 and the Fresnel sections 62a to 62c. Therefore, in the lens 60, the material that makes up the surface of the Fresnel surface has a higher thermal distortion temperature than the material that makes up the light incident section.

[0041] Examples of materials that make up the coating layer 64 include SiO2 and MgF2. The heat distortion temperature of PMMA resin is about 85-100°C, and the heat distortion temperature of PC resin is about 130-140°C, while the heat distortion temperatures of SiO2 and MgF2 are higher than those of these resin materials. Therefore, by making the coating layer 64 out of SiO2 or MgF2, heat deformation at the corners of the Fresnel sections 62a-62c can be suppressed.

[0042] The coating layer 64 can be formed by sputtering or a solution coating method. The thickness of the coating layer 64 is preferably in the range of 100 nm to 300 nm. If the thickness is less than 100 nm, it becomes difficult to suppress thermal deformation at the corners of the Fresnel portions 62a to 62c. If the thickness is greater than 300 nm, it becomes difficult to make the surface shape of the coating layer 64 conform to the corners of the Fresnel portions 62a to 62c, making it difficult to ensure optical properties.

[0043] As described above, in the lens 60 and vehicle lamp 100 of this embodiment, the material constituting the surface of the Fresnel surface has a higher thermal distortion temperature than the material constituting the light incident portion, thus suppressing thermoplastic deformation at the corners.

[0044] The present invention is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of Symbols]

[0045] 100... Vehicle lighting equipment 10…Support member 20…Light source 30…Reflector 40... Shade part 50...Lens holder 60... Lens 61...Holding part 61a...adjustment section 62a~62c...Fresnel section 63...Engaging part 64…Coating layer

Claims

1. It has a light inlet and a light outlet, The light-emitting section has a Fresnel surface in which multiple refractive surfaces are arranged in a stepped manner. The lens is characterized in that the material constituting the surface of the Fresnel surface has a higher thermal distortion temperature than the material constituting the light incident portion.

2. The lens according to claim 1, A holding portion having the aforementioned light incident portion, It has a Fresnel section equipped with the aforementioned light-emitting section, The lens is characterized in that the material constituting the surface of the Fresnel portion has a higher thermal distortion temperature than the material constituting the holding portion.

3. The lens according to claim 2, The lens is characterized in that the Fresnel portion has a thickness of 1 mm or less.

4. The lens according to claim 2, The lens is characterized in that the Fresnel portion is made of silicone resin.

5. The lens according to claim 2, The lens is characterized in that the Fresnel portion is provided with an engaging portion that engages with the holding portion.

6. The lens according to claim 1, The light incident portion and the Fresnel portion are integrally constructed from the same material. The lens is characterized in that a coating layer made of an inorganic material is formed on the surface of the Fresnel lens portion.

7. The lens according to claim 6, The lens is characterized in that the coating layer has a film thickness in the range of 100 nm to 300 nm.

8. The lens according to claim 6, The aforementioned coating layer is SiO ２ or MgF ２ A lens characterized by being composed of [the specified material].

9. A lens according to any one of claims 1 to 8, A light source that emits light, A vehicle lighting device characterized by comprising a reflective part that reflects light from the aforementioned light source.

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