Inner lens of vehicular lighting fixture
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-08-13
Smart Images
Figure JP2025004300_13082026_PF_FP_ABST
Abstract
Description
Inner lens for vehicle lighting fixture
[0001] The present invention relates to an inner lens for a vehicle lighting fixture.
[0002] The vehicle lighting fixture has a lamp housing having an opening, and an inner lens attached to the opening of the lamp housing.
[0003] Conventionally, an inner lens having a lens pitch of 0.3 mm or less is known (see Patent Document 1).
[0004] Japanese Utility Model Laid-Open No. 60-134203
[0005] However, in the case of an inner lens with a lens pitch of 0.3 mm, the lens cut can be visually recognized by the naked eye, and the presence of the lens cut cannot be completely eliminated. For this reason, the uniformity between the bright part and the dark part is low, a strong flicker is felt, and the appearance quality deteriorates.
[0006] The inner lens is injection-molded using, for example, a mold. Due to the processing limitations of machine tools and laser equipment for cutting the mold, a rounded shape (corner radius R) is formed at the corners on the surface of the inner lens. The corner R becomes a dead zone, and the area available for refraction by the lens is reduced. Therefore, when the lens pitch is reduced, the number of dead zones increases as the number of peaks and valleys increases. As a result, the light efficiency decreases.
[0007] That is, in the case of an inner lens with a lens pitch of 0.3 mm, it is impossible to achieve both good appearance quality and high light efficiency.
[0008] Therefore, an object of the present invention is to provide an inner lens for a vehicle lighting fixture that can achieve both good appearance quality and high light efficiency.
[0009] One aspect of the present invention for achieving the above object is the surface shape of an inner lens for a vehicle lighting fixture. The inner lens for a vehicle lighting fixture has uneven portions with a lens pitch of 150 to 10 micrometers and a corner R of 15 to 5 micrometers, and has a regular structure for refracting light emitted from a light source.
[0010] According to the present invention, it is possible to achieve both high appearance quality and high light efficiency.
[0011] This is a schematic cross-sectional view of a vehicle lighting device. This is a perspective view showing the surface shape of the inner lens. This is a schematic diagram showing the surface of the inner lens. This is a cross-sectional view showing the inner lens. This is a cross-sectional view showing the mold used to manufacture the inner lens. This is a cross-sectional view showing another example of an inner lens. This is a schematic diagram used to explain light efficiency.
[0012] Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The embodiments shown herein are illustrative examples for embodying the technical idea of the present invention and do not limit the present invention. Therefore, all other implementable forms, examples, and operational techniques that can be conceived by those skilled in the art without departing from the spirit of the present invention are included in the scope and spirit of the present invention, as well as in the claims and their equivalents.
[0013] Furthermore, the drawings attached to this specification may be schematically represented with changes to scale, aspect ratio, shape, etc., from the actual object for the sake of illustration and ease of understanding, but these are merely examples and do not limit the interpretation of the present invention.
[0014] <Embodiment> As shown in Figure 1, the vehicle lighting device 10 includes a lamp housing 20 having an opening 21, an inner lens 30 attached to the opening 21 of the lamp housing 20, a lamp chamber 40 formed between the lamp housing 20 and the inner lens 30, and a light source 50 arranged in the lamp chamber 40. The vehicle lighting device 10 includes headlights (high beam, low beam), side marker lights, front and rear turn signals, etc.
[0015] The inner lens 30 is formed from a transparent resin such as polycarbonate or acrylic. The inner lens 30 emits light from the light-emitting surface on the front side by emitting light from the front side that enters from the back side. The light source 50 is composed of a light-emitting element such as a light-emitting diode (LED). The light source 50 emits light radially toward the back side of the inner lens 30.
[0016] As shown in Figures 2, 3, and 4, the inner lens 30 of the vehicle lighting device 10 has a regular structure that refracts light coming from the light source 50, with a lens pitch p of 150 to 10 micrometers (μm) and an angle radius of 15 to 5 micrometers (μm).
[0017] The surface shape described above can be applied only to the front surface of the inner lens 30, only to the rear surface, or to both the front and rear surfaces. The surface and position to which the surface shape described above is applied can be selected according to the desired light distribution control.
[0018] The regular structure has a geometric and continuous structure, as shown in Figure 2.
[0019] The lens pitch p is the distance between the center points 32 of adjacent lens elements 31 in a plan view of the inner lens 30, as shown in Figure 3.
[0020] The regular structure has a prism shape (see Figure 4) or a curved lens shape (see Figure 6).
[0021] The regular structure is arranged without gaps in the vertical and horizontal directions, as shown in Figures 2 and 3. Each lens element 31 is in close contact with adjacent lens elements 31 in the vertical and horizontal directions.
[0022] Refer to Figure 7 to explain the optical efficiency LE.
[0023] The inner lens 30 is injection molded, for example, using a mold 60 (see Figure 5). Due to the processing limitations of the cutting tools and laser equipment used to cut the mold 60, a rounded shape 33 (corner radius) inevitably occurs at the corners of the inner lens 30 surface. The corner radius becomes a dead zone, reducing the area that can be used for refraction by the lens.
[0024] The optical efficiency LE was defined as follows: When the straight portion of the lens cut edge was set to 100%, the curved portion where an angle radius occurs was defined as the dead zone (i.e., the part that cannot be used for light distribution), and calculations were performed.
[0025] For example, if the angle R (radius r) is 220 micrometers (μm) and the lens pitch p is 1000 micrometers (μm), the optical efficiency LE can be calculated as follows: LE = ((1000 μm - 220 μm) / 1000 μm) × 100 = 78%.
[0026] (Function) The inner lens 30 has a regular structure that refracts light coming from the light source 50, with a lens pitch p of 150 to 10 micrometers and an angle radius of 15 to 5 micrometers.
[0027] With this configuration, by setting the lens pitch p to 150 micrometers or less, the visibility of the lens cuts to the naked eye is reduced, and their presence can be completely eliminated. The uniformity between bright and dark areas is increased, and glare can be reduced. If the lens pitch p is less than 10 micrometers, interference light is generated, causing a rainbow-like appearance. Therefore, by setting the lens pitch p to 10 micrometers or more, the generation of interference light can be suppressed. Thus, good appearance quality can be obtained.
[0028] By setting the angle radius to 15 micrometers or less, the area available for refraction of the lens can be increased even with a smaller lens pitch p, allowing for efficient light irradiation. By setting the angle radius to 5 micrometers or more, the mold 60 can be machined, and an inner lens 30 with good optical efficiency LE can be manufactured. Therefore, good optical efficiency LE can be obtained.
[0029] Therefore, the inner lens 30 of the vehicle lighting device 10 of this embodiment makes it possible to achieve both good appearance quality and good light efficiency LE. Because the light efficiency LE is good, it becomes easier to design the light distribution of the lens and obtain the desired light distribution performance.
[0030] A regular structure possesses both geometric and continuous properties. This configuration allows for efficient refraction of light in a targeted direction, thereby improving the efficiency of light extraction.
[0031] The regular structure has a prism shape or a curved lens shape. With this configuration, the prism shape or curved lens shape allows for more efficient refraction of light in the desired direction. Therefore, the efficiency of light extraction can be further improved.
[0032] The regular structure is arranged without gaps in both vertical and horizontal directions. With this configuration, there are no gaps between the lens elements 31, so the number of lens elements 31 per unit area can be increased. As a result, light can be refracted more efficiently in the desired direction. Therefore, the efficiency of light extraction can be further improved.
[0033] <Evaluation> Next, with reference to Table 1 below, examples and comparative examples in which glare (appearance quality) and light efficiency LE were evaluated will be described.
[0034]
[0035] The parameters set were lens pitch p (μm), angle radius (μm), whether or not the structure is regular, and the manufacturing method of the mold 60. In the manufacturing method, "end mill" refers to a normal end mill, with a machining limit of approximately 220 micrometers. On the other hand, "micro end mill" has a machining limit of approximately 15 micrometers. As an example of a micro end mill, one can mention the "Micro Edge Series" ultra-fine machining end mill manufactured by Nisshin Tool Co., Ltd. "Laser" has a machining limit of approximately 5 micrometers.
[0036] The "glare" result indicates the result of sensory evaluation. A double circle indicates that glare was not perceived. A circle indicates that glare was hardly perceived. An X indicates that glare was perceived. The light efficiency LE (%) is a value calculated according to the definition described above.
[0037] Comparative Examples 1 and 2 exhibited glare and also had low light efficiency (LE).
[0038] Comparative Examples 3 and 4 had an irregular surface shape for the inner lens 30, and although glare was hardly noticeable, light distribution control was not possible.
[0039] Comparative Example 5 involved cutting the mold 60 with a micro end mill, so the corner R could be made as small as 15 micrometers. However, since the lens pitch p was as large as 500 micrometers, glare was recognized.
[0040] Comparative Example 6 attempted to manufacture a surface shape with a lens pitch p as small as 100 micrometers by cutting the mold 60 with an end mill, but it could not be manufactured.
[0041] On the other hand, in Examples 1, Example 2, and Example 3, since the mold 60 was cut with a micro end mill, the corner R could be made as small as 15 micrometers.
[0042] In Example 1, the lens pitch p was 150 micrometers, and almost no glare could be recognized. Since the lens pitch p was relatively large, the light efficiency LE was also as high as 90.8%.
[0043] In Example 2, the lens pitch p was 100 micrometers, and no glare could be recognized, and the light efficiency LE was also as high as 86.2%.
[0044] In Example 3, the lens pitch p was 50 micrometers, and no glare could be recognized. Since the lens pitch p was relatively small, the light efficiency LE was 72.3%.
[0045] In Example 4, since the mold 60 was cut with a laser, the corner R could be made as small as 5 micrometers. In Example 4, the lens pitch p was 10 micrometers, and almost no glare could be recognized. Since the lens pitch p was smaller compared to the other Examples 1 to 3, the light efficiency LE was 53.8.
[0046] From the results of Examples 1 to 4, it was confirmed that the inner lens 30 has concavo-convex portions with a lens pitch p of 150 to 10 micrometers and a corner R of 15 to 5 micrometers, and by having a regular structure that refracts the light emitted from the light source 50, it is possible to achieve both good appearance quality and good light efficiency LE.
[0047] As described above, the inner lens 30 of the vehicle lighting fixture 10 of the present invention has been explained. However, the present invention is not limited to the configurations described in the above-described embodiments and Examples 1 to 4, and can be appropriately changed based on the description of the claims.
[0048] In addition, the following embodiments are also included in the scope of the present invention: the inner lens 30 of the vehicle lighting fixture 10 according to claim 3, which has the features of claim 4.
[0049] 10: Vehicle lighting fixture 20: Lamp housing 21: Opening 30: Inner lens 31: Lens element 32: Center point 33: Rounded shape of the corner (Corner R) 40: Lamp chamber 50: Light source 60: Mold p: Lens pitch
Claims
1. An inner lens for a vehicle lighting device, having a surface shape with a lens pitch of 150 to 10 micrometers and an angle radius of 15 to 5 micrometers, and having a regular structure that refracts light emitted from a light source.
2. The regular structure has a geometric and continuous structure, the inner lens of the vehicle lighting device according to claim 1.
3. The regular structure has a prism shape or a curved lens shape, the inner lens of a vehicle lighting device according to claim 1 or claim 2.
4. The inner lens of a vehicle lighting device according to claim 1 or claim 2, wherein the regular structure is arranged without gaps in the vertical and horizontal directions.