Vehicle lighting device

Abstract

To provide a lighting device for a vehicle having a light guide and a housing which can prevent occurrence of knocking sound without using a lubricant.SOLUTION: A lighting device for a vehicle has a light source, a long light guide for guiding light emitted from the light source, and a housing storing the light guide, wherein the housing includes a lens part for receiving light emitted from the light guide, and emitting the light to the outside of the device, and is composed of a translucent resin having visible light transmittance of 35-85%, and a combination of resins for suppressing abnormal sound when the materials of the light guide and the housing are slid with each other is selected.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a vehicle lighting device. [Background technology]

[0002] The interior (and sometimes exterior) of vehicles such as automobiles are provided with lighting structures for use by passengers. In lighting structures, light emitted from a lighting device may be used as direct light that directly illuminates objects such as people, objects, and spaces, or as indirect light that is reflected from irradiated portions of automobile interior components and indirectly illuminates objects such as people, objects, and spaces. Whether the lighting is used as indirect light or direct light, the light may be emitted through a diffusing material. For example, Patent Document 1 describes a lighting device installed in the interior of a vehicle, in which light emitted from a light guide is emitted into the passenger compartment through a lens made of a diffusing material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6862119 specification Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional lighting devices, polycarbonate is known as a material that holds a light guide at a practical level and covers the light-emitting surface of the light guide as a lens to transmit and emit light. Polycarbonate is widely used as an engineering plastic and is a material that provides high transparency. Patent Document 1 also lists polycarbonate as a specific example of a material for a diffusing material that includes a lens portion.

[0005] However, when a light guide made of acrylic resin is combined with a polycarbonate housing, there is a problem of noise occurring during sliding. Particularly in vehicle lighting devices, loads are generated when the door is opened or closed, or when accelerating or decelerating while driving, resulting in noise due to stick-slip. This phenomenon occurs because the light-receiving surface of the lens is positioned opposite the light-emitting surface of the long light guide. Therefore, conventionally, a lubricant has been placed between the polycarbonate housing and the light guide to prevent noise. However, using a lubricant increases costs due to the labor and material costs required for application.

[0006] The present invention aims to provide a vehicle lighting device that can suppress the generation of abnormal noise caused by sliding between the housing and the light guide without using a lubricant, thereby simplifying the manufacturing process and reducing costs. [Means for solving the problem]

[0007] The first configuration of the present invention is A light source and an elongated light guide that guides the light emitted from the light source; a housing for accommodating the light guide, the housing includes a lens portion that receives light emitted from the light guide and emits the light to the outside of the device; It is made of translucent resin with a visible light transmittance of 35 to 85%. The vehicle lighting device is characterized in that the materials of the light guide and the housing are selected to be a combination of resins that can suppress abnormal noise when they slide against each other.

[0008] According to the lighting device having the above configuration, there is no need to apply a lubricant to prevent noise during sliding, which is advantageous in terms of cost. By using a translucent resin for the housing, uneven light can be suppressed.

[0009] In the vehicle lighting device having the above configuration, the light guide may be made of an acrylic resin, and the housing may be made of a polypropylene resin.

[0010] In the vehicle lighting device having the above configuration, the housing may have a U-shaped cross section, and in the longitudinal direction, an opening at a base end where the light source is disposed, and a tip end opposite the base end may be closed by an end wall. With this configuration, rigidity is imparted to the housing, and unnecessary light leakage near the tip can be suppressed or prevented.

[0011] In the vehicle lighting device having the above configuration, the light guide may be disposed so that the distance between the end wall and the tip of the light guide is 0.5 mm to 20.0 mm. This configuration can prevent a load from being applied between the housing and the light guide due to a difference in thermal contraction rate between the housing and the light guide, which are made of different materials.

[0012] In the vehicle lighting device, the light guide may have a side surface on which an optical pattern is formed along the longitudinal direction, which allows the light to be effectively reflected and guided over a long distance. [Effects of the Invention]

[0013] According to the present invention, in a lighting device to be mounted on a vehicle, it is possible to prevent abnormal noise due to stick-slip during sliding between the housing and the light guide without using a lubricant between the housing and the light guide, and therefore it is possible to assemble the light guide directly into the housing, thereby simplifying the manufacturing process of the lighting device. [Brief explanation of the drawings]

[0014] [Figure 1A] 1 is a perspective view showing an illumination device according to an embodiment of the present invention; [Figure 1B] 1B is a perspective view showing a housing provided in the lighting device of FIG. 1A. FIG. [Figure 1C]1B is a perspective view showing a light guide provided in the lighting device of FIG. 1A. FIG. [Figure 1D] 1B is a perspective view showing the configuration of a light source included in the lighting device of FIG. 1A. FIG. [Figure 2] FIG. 2 is a side view showing the configuration of the tip of the lighting device. [Figure 3A] 1 is a cross-sectional view showing a configuration of an illumination device according to an embodiment of the present invention. [Figure 3B] FIG. 3B is a cross-sectional view showing the configuration of a modified example of the lighting device shown in FIG. 3A. [Figure 3C] FIG. 10 is a cross-sectional view showing the configuration of an illumination device according to another embodiment. [Figure 4] 10A and 10B are diagrams showing an example of the arrangement of optical patterns in a light guide used in an illumination device according to an embodiment of the present invention. [Figure 5] 10 is a graph showing that the luminance distribution varies depending on the resin used for the lens. [Figure 6] 1 is a schematic diagram illustrating the arrangement of a lighting device of the present invention in a door trim of a vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1A is a perspective view showing the configuration of an illumination device 1 according to one embodiment of the present invention. The illumination device includes a housing 10, a light guide 20 housed in the housing 10, and a light source 30 connected to the base end of the light guide 20 and causing light to enter the light guide 20. The light source 30 is assembled to the housing 10 via a light source case 40.

[0016] As shown in FIG. 1B, the housing 10 includes a storage section 10d having a U-shaped cross section and made up of a bottom wall 10a, a top wall 10b, and side walls 10c. The light guide 2 is stored in the storage section 10d. An end wall 10e is provided at the tip of the housing 10, but the base end is open. Spacers 10f are arranged at regular intervals on the inner bottom surface of the storage section 10d (the upper surface of the bottom wall 10a) to ensure a gap (see FIG. 3A) between the inserted light guide 2 and the bottom wall 10a. The top wall 10b is provided with fixing sections 10g for fixing the lighting device 10 to the interior of the vehicle. In the illustrated embodiment, the bottom wall 10a of the storage section 10d serves as a lens section 100, which emits light guided by the light guide 20.

[0017] 1C, the light guide 20 has an elongated shape with a rectangular cross section, and an optical pattern (not shown) may be provided on one side surface 20a. The light source 30 includes a light emitter (LED) 30b arranged on a substrate 30a shown in FIG. 1D, and a socket 30d connected to the substrate 30a via a lead 30c, and a harness (not shown) extending from a power source (not shown) is connected to the socket 30d.

[0018] The shapes and dimensions of the housing 10 and the light guide 20, and the configuration of the light source 30 are not limited to those shown in the drawings. For example, the length and cross-sectional area of ​​the housing 10 and the light guide 20 in FIG. 1A and the shape of the fixing portion 10d of the housing 10 can be selected appropriately depending on the installation location of the lighting device 1. For example, the light source 30 may be directly assembled to the light guide 20 via a light source case 40. The light source 30 may also be directly connected to a power source (not shown) via a harness (not shown).

[0019] FIG. 2 is a schematic side view showing the tip portion of the lighting device 1. The presence of an end wall 10e at the tip of the housing 10 provides a certain degree of rigidity to the housing 10 and reduces or prevents light leakage from unintended locations (such as gaps between components) due to light emitted from the tip 20c of the light guide 20. When the light guide 20 and the housing 10 are formed from different materials with different thermal shrinkage rates (e.g., acrylic resin and polypropylene), it is preferable to provide a certain distance D between the tip 20c of the light guide 20 and the end wall 10e of the housing 10, as shown in the figure. The optimum value of this distance D varies depending on the materials and lengths of the light guide 20 and the housing 10, but is approximately 0.5 to 20.0 mm (e.g., 2.5 mm).

[0020] FIG. 3A is a schematic cross-sectional view of the lighting device 10. In the housing 10, which has a U-shaped cross section, one wall, for example, the bottom wall 10a, serves as the lens portion 100. Light guided through the light guide 20 is emitted from all four sides. One side (the bottom surface in the illustrated example) facing the lens portion 100 (the bottom wall 10a in the illustrated example) serves as the designed light exit surface 20b, and the opposite side (the top surface in the illustrated example) serves as the reflecting surface 20a. The light guide 20 is held in the housing 10 by a spacer 10f shown in FIG. 1B or a locking claw (not shown), and a gap layer 40 (usually an air layer) exists between the three walls 10a, 10b, and 10c and the light guide 20. As a result, the reflecting surface 20a and the light exit surface 20b serve as the interfaces between the light guide 20 and the gap layer 40, respectively. The light that has entered the light guide 20 is guided while being reflected between the interface between the exit surface 20b and the side wall 10c of the housing 10 and the reflecting surface 20a, and is then emitted from the exit surface 20b.

[0021] FIG. 3B is a schematic cross-sectional view illustrating a modified example of the lighting device 1. As shown in FIG. 3B, in one modified example, the bottom wall 10a of the housing 10 may be thinner than the side wall 10c and the top wall 10b. Depending on the configuration of the lighting device 1, if the bottom wall 10a or the top wall 10b is used to output light as a lens portion 100, the bottom wall 10a or the top wall 10b may be thinner than other portions. Furthermore, depending on the design requirements of the housing, the wall portion that becomes the lens portion 100 may be thicker than the other walls. For example, the thickness of the lens portion 100 may be 0.5 to 5 mm, for example, about 2 mm.

[0022] As shown in Fig. 3B, a groove-shaped optical pattern 20d may be provided on the reflecting surface 20a of the light guide 20. Although the size is exaggerated in the figure for the sake of explanation, the ratio d / T of the groove depth d of the optical pattern 20d to the thickness T of the light guide 20 may be 0.01 to 0.25. The cross-sectional shape of the groove of the optical pattern 20d is not particularly limited, and may include a semicircular shape, a triangular shape, an elliptical shape, a rectangular shape, etc. The thickness s of the gap layer 40 between the emission surface 20b of the light guide 20 and the lens portion 100 (bottom wall 10a) may be, for example, approximately 0.05 to 2 mm.

[0023] In the above description, one side surface of the U-shaped cross section housing 10 is used as the lens portion 100. However, depending on the design of the lighting device, two side surfaces may be used as the lens portion 100. For example, in the configuration shown in Fig. 3B, the side surface 20e that is approximately perpendicular to the light exit surface 20b of the light guide 20 may also be used as the second light exit surface, and the side wall 10c of the housing may also be used as the lens portion 100. In this case, the side surface 20f opposite to the second light exit surface 20e of the light guide 20 may be used as a second reflecting surface, and an optical pattern (not shown) may be provided thereon as necessary.

[0024] 3C is a schematic cross-sectional view illustrating another embodiment of the lighting device 1. As shown in this figure, a light guide 20 may be held by a housing 11 having a lens portion 11a with an L-shaped cross section and a holding portion 11b provided along a portion of the housing in the longitudinal direction, and light emitted from an emission surface 20b of the light guide 20 may be received by the lens portion 11a and emitted from a light emission surface 11c at the tip of the portion separated from the light guide 20. In this case, the width from the light receiving surface 11d of the lens portion 11a to the light emission surface 11c may be approximately 2 to 20 mm.

[0025] In the lighting device 1 of the present invention, the housing 10 that holds the light guide 20 is made of a translucent resin with a visible light transmittance of 35 to 85%, and the materials of the light guide 20 and the housing 10 are selected so as to be a combination of resins that can suppress abnormal noise when they slide against each other. In conventional lighting devices, polycarbonate is generally used for the housing, and therefore, in practical use, a lubricant is typically applied to the inner surface of the housing to provide a lubricant between the housing and the light guide to prevent abnormal noise due to stick-slip. However, in the present invention, it has been discovered that by appropriately selecting the materials for forming the light guide 2 and the housing 10, abnormal noise due to stick-slip during vehicle operation can be prevented without using a lubricant.

[0026] As a combination of the above materials, when an acrylic resin (for example, PMMA) is used for the light guide 20, it is preferable to use polypropylene for the housings 10 and 11.

[0027] The housing 10 is made of a translucent resin with a visible light transmittance of 35 to 85%. By making the housing 10 out of a translucent resin, light can be diffused within the housing 10, preventing uneven light. If necessary, a light diffusing agent such as silicone particles may be dispersed in the resin to adjust the visible light transmittance to within the above range.

[0028] FIG. 4 is a schematic diagram showing the arrangement of optical patterns 20d on the reflecting surface 20a of the light guide 20. When a long light guide 20 is used in a lighting device 1, groove-shaped optical patterns 20d may be arranged at a predetermined interval (pitch) p to increase the reflection efficiency on the reflecting surface 20a. Conventionally, low-haze polycarbonate lenses have been used. Even if the haze is adjusted by graining or dispersing a diffusing agent, uneven light is likely to occur due to the difference in the amount of light emitted from the area where the reflected light from the optical pattern exits and the other light-emitting areas. Therefore, to achieve uniform light emission, the pitch of the optical patterns must be made finer. In contrast, if a light diffusing agent is further dispersed in a translucent resin such as polypropylene, even if the interval p of the optical patterns 20d is increased to, for example, 5 mm or more, the light diffusion by the lenses suppresses uneven light and allows for relatively uniform light emission. This also simplifies the processing of the light guide. For example, if the light guide distance is within 1 m, the interval p of the groove-shaped optical patterns may be approximately 5 to 20 mm. The interval p may be changed depending on the distance from the light source, and the interval p may be shortened in a portion farther away from the light source.

[0029] To verify the above effects, we compared the luminance distribution of lenses made of polycarbonate and polypropylene. A 5mm-wide PMMA light guide rod was used as the light guide, and a 5mm-long, semicircular groove optical pattern with a 0.1mm radius cross section was created on the reflective surface at 10mm intervals. A white LED was used as the light source, and 5mm-thick polypropylene (containing a diffusing agent) and 5mm-thick polycarbonate lenses with a textured finish on the exit surface were used. A luminance meter (Konica Minolta CA-2500) was positioned so that the light incident surface was 25cm from the lens surface, and the luminance distribution of each lens was measured. The results are shown in Figure 5.

[0030] In Figure 5, the upper line shows the relative intensity distribution of the luminance emitted from the polypropylene lens, and the lower line shows the relative intensity distribution of the luminance emitted from the polycarbonate lens. As is clear from the figure, in the case of polycarbonate, the luminance distribution is uneven due to the difference in luminance between the area where reflected light from the optical pattern is emitted and other luminous areas, but for light that passes through the polypropylene lens, the luminance difference is suppressed due to diffusion within the lens.

[0031] 4 shows the optical pattern 20d in the form of grooves that are substantially perpendicular to the extension direction of the light guide, i.e., the longitudinal direction, but the shape of the optical pattern 20d is not limited to this and may be recesses of a predetermined shape, such as a hemisphere, a cone, a truncated cone, a pyramid, or a truncated pyramid, provided at predetermined intervals along the extension direction of the light guide. In this case, recesses of a constant depth may be provided at constant intervals, or the depth and spacing of the recesses may be varied; for example, the recesses may be made deeper as the distance from the light source increases.

[0032] Polypropylene has a lighter specific gravity than polycarbonate, so using polypropylene for the housing 10 is also effective in reducing the weight of the vehicle. Furthermore, because it has high chemical resistance, the lens portion does not deteriorate when cleaning the vehicle interior, allowing for long-term use. It is also highly recyclable, which reduces the burden on the environment.

[0033] 6 is a schematic diagram illustrating the arrangement of the lighting device 1 in the door trim 2 of a vehicle. The lighting device 1 may be arranged on the decorative member 2a of the door trim 2 to directly illuminate the interior of the vehicle, or may be arranged inside the door pocket 2b to provide indirect lighting. Note that while FIG. 4 shows an example of the arrangement of the lighting device 1 in the door trim 2 of the front door, the location of the lighting device 1 is not limited to this, and the lighting device 1 may also be arranged on the back door, the rail door, or not only on the door trim but also on the instrument panel, ceiling, center console, etc.

[0034] The present invention is not limited to the above-described embodiment, and modifications and variations are possible within the scope of the claims. [Explanation of symbols]

[0035] 1. Lighting equipment 2 door trim 2a Decorative material 2b Door pocket 10, 11 Housing 10a bottom wall 10b Upper wall 10c side wall 10d Storage section 10e End wall 10f Retaining member 10g fixing material 11a, 100 lens part 11c Idemitsu surface 20 Light guide 20a reflective surface 20b Output surface 20c tip 20d optical pattern 30 light source 30a board 30b Luminous object 30c conductor 30d socket 40 void layer

Claims

[Claim 1] A light source and an elongated light guide that guides the light emitted from the light source; a housing for accommodating the light guide, the light guide is made of acrylic resin and has a side surface on which an optical pattern is formed along the longitudinal direction; the housing includes a lens portion that receives light emitted from the light guide and emits the light to the outside of the device; It is made of a translucent polypropylene resin with a visible light transmittance of 35 to 85%, The materials of the light guide and the housing are selected to be a combination of resins that can suppress abnormal noise when they slide against each other, The housing has a U-shaped cross section, In the longitudinal direction, an opening is provided at a base end where the light source is disposed, a distal end opposite the proximal end being closed by an end wall; the light guide is disposed so that the distance between the end wall and the tip of the light guide is 0.5 mm or more and 20.0 mm or less; The housing has a spacer inside a receiving portion that receives the light guide, and the spacer forms a gap layer between the inner wall surface of the receiving portion and the light guide. A vehicle lighting device characterized by:

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