Heater arrangement structure for the outer lens of a vehicle light fixture

Abstract

To provide an arrangement structure capable of improving light distribution performance in a heater arranged in an outer lens of a vehicle lamp.SOLUTION: An outer lens 2 includes a first region 21 facing an inner lens 33 and a second region 22 other than the first region. The first region 21 includes a third region 23 facing the center of the inner lens 33. The heater 11 comprises a hot wire 12 that generates heat when energized. The hot wire 12 includes a first portion 13 arranged in the first region 21 and a second portion 14 arranged in the second region 22. The first portion and the second portion are arranged so that an areal density in which the first portion 13 is arranged in the third region 23 is smaller than an areal density in which the second portions 14 are arranged in the second region 22.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to an arrangement structure of heating wires that function as a snow melting heater in an outer lens of a vehicle lamp.

Background Art

[0002] In recent years, as a component of vehicle lamps, LED light sources that do not emit infrared rays have been widely adopted. Although LED light sources and PES lenses have the advantage of suppressing the temperature rise of the lamp, on the other hand, there is a problem that snow accumulated on the lamp surface is difficult to melt.

[0003] In order to solve this problem, a technique of a snow melting heater is known in which heating wires are wound around the entire outer lens and the heating wires are heated by energization to melt the snow accumulated on the outer lens. For example, in Patent Document 1, a technique of a lens heater is proposed in which a substantially transparent heat-flexible substrate is provided inside the lens, a conductive ink circuit (heating wire) is arranged on the heat-flexible substrate, and the lens is heated by energizing the conductive ink circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, as shown in Figure 6, with conventional technology, the heating element 12 of the heater blocks the light L from the light source, and light scattering occurs near the edge 12a of the heating element 12. As shown in Figure 7, there was a problem in that glare increased particularly in region X, near the cutoff line C of the Lo beam. In addition, the heating element 12 blocked light, reducing visibility at long distances for both the Lo and Hi beams. Figure 8 shows a graph of the "Lo beam road surface illumination curve simulation" comparing the case without heating element (dashed line) and the case with heating element (solid line). From this comparison, it is clear that the blocking by the heating element reduces visibility at long distances.

[0006] Therefore, the purpose of this disclosure is to provide a heater arrangement structure that can improve light distribution performance. [Means for solving the problem]

[0007] To solve the above problems, the heater arrangement structure of this disclosure has the following features. (1) A heater arrangement structure for an outer lens of a vehicle lamp, wherein the heater includes a heating element that generates heat when energized, the vehicle lamp includes a light distribution means for distributing light from a light source, the outer lens includes a first region facing the light distribution means and a second region other than the first region, the first region includes a third region facing the center of the light distribution means, the heating element includes a first part disposed in the first region and a second part disposed in the second region, the second parts are disposed parallel to each other, and the surface density of the first part disposed in the third region is smaller than the surface density of the second part disposed in the second region.

[0008] (2) A heater arrangement structure having the features of (1), wherein the vehicle lighting fixture includes a lamp unit, the light distribution means is the inner lens of the lamp unit, the inner lens and the third region are arranged in a circular shape when viewed from the front of the vehicle lighting fixture, and the radius of the third region is 1 / 2 or less of the radius of the inner lens.

[0009] (3) A heater arrangement structure having the characteristics of (1) or (2), wherein the first part includes a curved portion that bypasses the third region.

[0010] (4) A heater arrangement structure having the characteristics of (1) or (2), wherein the first part is provided in a narrower width than the second part.

[0011] (5) A heater arrangement structure having the characteristics of (4), wherein the first part is provided to be narrower and thicker than the second part. [Effects of the Invention]

[0012] According to the heater arrangement structure of this disclosure, the surface density of the first part arranged in the third region is configured to be smaller than the surface density of the second part arranged in the second region. In other words, the light shielding rate of the third region is configured to be lower than the light shielding rate of the second region. Therefore, it is possible to prevent a decrease in the light distribution performance of the vehicle lighting fixture in the range that can contribute to light distribution, in particular in the main range that contributes to light distribution. [Brief explanation of the drawing]

[0013] [Figure 1] (a) a front view and (b) an AA line end view of a headlamp illustrating one embodiment of the present disclosure. [Figure 2] This is a schematic diagram showing an enlarged view of the main part of Figure 1, which illustrates the heater arrangement structure of the outer cover. [Figure 3] This is a schematic diagram showing an enlarged view of the main part of Figure 1, which illustrates the heater arrangement structure of the outer cover. [Figure 4] This is a schematic diagram showing an enlarged view of the main part of Figure 1, which illustrates the heater arrangement structure of the outer cover. [Figure 5] This is a schematic diagram showing an enlarged view of the main part of Figure 1, which illustrates a modified example of the heater arrangement structure of the outer cover. [Figure 6] This is a schematic diagram showing an enlarged view of the main parts of Figure 1, which illustrates the conventional heater installation structure. [Figure 7] This is a schematic diagram showing the field of view where headlamp glare may occur. [Figure 8] This graph shows the simulation results of the road surface illumination curve for low beams. [Modes for carrying out the invention]

[0014] Hereinafter, an embodiment of the present disclosure applied to a headlamp will be described with reference to the drawings. The headlamp 1 shown in Figure 1 is a headlamp mainly used in large vehicles 51 such as trucks (see Figure 7), and comprises a lamp body 6 attached to the vehicle body and an outer lens 2 made of a transparent resin material. The outer lens 2 and the lamp body 6 are sealed at the periphery, and a lamp chamber 7 is formed inside them.

[0015] The lamp chamber 7 contains an HL (headlamp) unit 3, an SL (signal lamp) unit 4, and a fog lamp unit 5. The HL unit 3 includes an LED light source 31 for the HL, a reflector 32, an inner lens 33, a socket (not shown), etc., and is tiltably supported on the lamp body 6 via an aiming mechanism (not shown). The inner lens 33 is made of PES (polycarbonate) material and functions as a light distribution means for distributing the light L from the LED light source 31 to the outside of the vehicle. It is also possible to use other transparent resin materials for the inner lens 33.

[0016] The outer lens 2 is equipped with a heater 11 (12, 15) located inside the lamp chamber. The heater 11 is a conductive ink circuit and comprises a heating element 12 and a connector 15 that supplies power to the heating element 12. The heating element 12 can preferably be made of conductive ink or the like, which generates heat when energized. As for the manufacturing method of the heater 11, for example, a method can be used in which silver paste is applied to the inner surface of the lamp chamber of the outer lens 2 with a dispenser and then heat-cured. The heating element 12 is arranged to run around a predetermined area of ​​the outer lens 2, and both ends of the heating element 12 are connected to the connector 15. The area in which the heater is installed can be changed as appropriate.

[0017] As shown in FIGS. 2 to 4, the outer lens 2 includes a first region 21 facing the inner lens 33 and a second region 22 that is a region other than the first region. The first region 21 includes a third region 23 facing the central portion of the inner lens 33. Here, the first region 21 is a range that can contribute to light distribution, and the second region 22 is a range that does not contribute to light distribution. Also, the third region 23 is a main range that contributes to light distribution. The third region 23 is a region where it is particularly desired to suppress a decrease in light distribution performance. For example, when the third region 23 has a size of 1 / 2 or less of the radius of the inner lens 33, it is possible to achieve both heat generation performance and light distribution performance.

[0018] The heating wire 12 includes a first portion 13 disposed in the first region 21 and a second portion 14 disposed in the second region 22. The second portion 14 is folded back at the end of the second region 22 and is disposed parallel to each other. When the thickness of the heating wire 12 is about 1 mm, the interval (pitch) of the heating wire 12 is preferably about 10 to 12 mm, and when the thickness of the heating wire 12 is about 0.5 mm, the interval is preferably about 6 to 8 mm. By disposing the heating wire 12 in this way, a temperature rise of 40 to 60 degrees is realized.

[0019] The first portion 13 of the heating wire 12 has a curved portion 13a that curves so as to bypass the third region 23. The distance d between the apex of the curved portion 13a and the horizontal position can be about 4.5 mm (see FIG. 2) to 6 mm (see FIG. 3). The curvature of the curved portion 13a is preferably provided to be about the same as the curvature of the inner lens 33. For example, R30 mm is suitable. When it is desired to ensure further light distribution performance, as shown in FIG. 4, it is also possible to provide the heating wire 12 only at the peripheral edge of the first region 21.

[0020] According to the arrangement structure of the heater 11 having the above configuration, since the first portion 13 is arranged so as to bypass the third region 23, the surface density of the heating wire 12 (first portion 13) disposed in the third region 23 is smaller than the surface density of the heating wire 12 (second portion 14) disposed in the second region 22. Therefore, in the third region 23, light shielding by the heating wire 12 and light scattering by the surface of the heating wire are suppressed, and glare near the cut-off line of the Lo beam can be reduced.

[0021] Next, a modified example of the heater arrangement structure of this disclosure will be described. As shown in Figure 5, the width w1 of the first portion 13 of the heating element 12 can be made narrower than the width w2 of the second portion 14. For example, if the second portion 14 is a heating element 12 with a thickness of 1 mm, the first portion 13 can be made 0.5 mm thick, which is half the thickness of w2. Because the first portion 13 is made narrower, the surface density of the heating element 12 (first portion 13) arranged in the first region 21 is smaller than the surface density of the heating element 12 (second portion 14) arranged in the second region 22. Therefore, in the first region 21, the transmission of light L through the inner lens 33 is not obstructed, and the light distribution performance can be improved.

[0022] In this case, it is preferable to further provide the first part 13 with a thicker thickness h. Here, "thicker thickness" refers to a state in which the part is bulkier toward the inside of the lamp chamber 7. For example, the thickness h1 of the first part 13 can be twice the thickness h2 of the second part 14. If there is an imbalance in the cross-sectional area between the first part 13 and the second part 14, an imbalance will occur in the resistance value when energized, and a high load will be placed on the narrow first part 13, which may cause it to break. By arranging the first part 13 to be narrow and thick, the resistance value between the first part 13 and the second part 14 can be made uniform, preventing abnormal heat generation and breakage of the heating element 12, as well as improving the durability of the heating element 12.

[0023] This disclosure is not limited to the embodiments described above, and it is possible to implement the invention by appropriately changing the shape and configuration of each part without departing from the spirit of this disclosure. For example, it is possible to turn on the heater 11 even when the headlamp 1 is not illuminated. [Explanation of Symbols]

[0024] 1 Headlamp 2 outer lenses 3 HL units 4 SL units 5. Fog lamp unit 6. Light fixture body 7 Lamp room 11 Heater 12 Hot wire (a: edge) 13 Part 1 (a: curved section) 14 Part 2 15 connectors 21 First area 22 Second area 23 Third area 31 LED light source 32 reflectors 33 Inner Lens 51 vehicles L light

Claims

1. A heater arrangement structure for the outer lens of a vehicle light fixture, The heater includes a heating element that generates heat when electricity is applied, The aforementioned vehicle lighting fixture includes a light distribution means for distributing light from a light source, The outer lens includes a first region facing the light distribution means and a second region other than the first region. The first region includes a third region facing the central part of the light distribution means, The heating element includes a first portion disposed in the first region and a second portion disposed in the second region. The second parts are arranged parallel to each other, The surface density of the first portion arranged in the third region is smaller than the surface density of the second portion arranged in the second region. A heater arrangement structure characterized in that the first portion includes a curved portion that bypasses the third region.

2. The aforementioned vehicle lighting fixture includes a lamp unit, The light distribution means is the inner lens of the lamp unit, The inner lens and the third region are arranged in a circular shape when viewed from the front of the vehicle light fixture. The heater arrangement structure according to claim 1, wherein the radius of the third region is 1 / 2 or less of the radius of the inner lens.

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