Vehicular lighting fixture

Abstract

To provide a new technique which reduces appearance failure of an outer cover.SOLUTION: A vehicular lighting fixture 10 includes: a lamp body 12; an outer cover 14 which forms a lamp chamber by covering an opening of the lamp body; a lighting fixture unit 18 which is stored inside the lamp chamber 16; and a dew condensation member 24 which is arranged inside the lamp chamber 16, and where released moisture is condensed. The outer cover 14 includes: a front surface part 14a through which light emitted from the lighting fixture unit 18 is transmitted; and an extension part 14b which extends backward from an upper part of the front surface part 14a. The dew condensation member 24 is arranged so as to shield at least a part of a path where released moisture M goes toward the extension part 14b.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to vehicle lamps.

Background Art

[0002] When the surface temperature of the outer cover of a vehicle lamp is lower than the dew point in the lamp chamber, condensation occurs on the inner surface of the outer cover. When the vehicle lamp is cooled at night and irradiated with sunlight in the morning, the sunlight passes through the outer cover and warms the members in the lamp chamber. When the temperature in the lamp chamber thus increases, the moisture absorbed by the members in the lamp chamber is released, increasing the humidity in the lamp chamber. As a result, condensation is likely to occur on the inner surface of the low-temperature outer cover.

[0003] When condensation occurs on the inner surface of the outer cover in this way, it may damage the appearance. Therefore, a technique of providing a film with good wettability (anti-fog coating) on the inner surface of the outer cover is known (see, for example, Patent Document 1). This anti-fog coating prevents fogging by forming a water film thereon when water vapor condenses.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when sunlight enters a vehicle lamp at an angle close to the horizontal direction in the early morning, the sunlight enters the interior of the lamp from the front portion of the outer cover and warms the internal components. When the components are made of resin, moisture may vaporize from the inside and be released into the lamp chamber. The released moisture may condense at relatively low-temperature locations in the lamp chamber. For example, the horizontal portion at the upper part of the outer cover is difficult to be warmed by the morning sunlight, and the released moisture may condense. When a certain amount of the condensed moisture accumulates and is transmitted from the horizontal portion to the front portion by its own weight and drips down, even if the condensed moisture vaporizes again, traces of the dripping trajectory may remain on the appearance.

[0006] The present invention has been made in view of such circumstances, and one of its exemplary purposes is to provide a new vehicle lamp with reduced appearance defects of the outer cover.

Means for Solving the Problems

[0007] In order to solve the above problems, a vehicle lamp according to an aspect of the present invention includes a lamp body, an outer cover that forms a lamp chamber by covering an opening of the lamp body, a lamp unit housed inside the lamp chamber, and a condensation member disposed inside the lamp chamber where the released moisture condenses. The outer cover has a front portion through which light emitted from the lamp unit passes, and an extension portion that extends rearward from the upper portion of the front portion. The condensation member is disposed so as to shield at least a part of a path along which the released moisture travels toward the extension portion.

[0008] According to this aspect, by condensing the released moisture with the condensation member before it reaches the extension portion, the amount of condensation at the extension portion is reduced. As a result, the situation where water droplets condensed at the extension portion drip onto the front portion of the outer cover is improved.

[0009] The vehicle lamp may further include a heat dissipation portion that dissipates heat generated by the lamp unit. The condensation member may be disposed above the heat dissipation portion and function as a rectifying plate that causes the heat dissipated by the heat dissipation portion to flow from the rear to the front. Thereby, the condensation member cools the heat dissipated by the heat dissipation portion and is less likely to condense due to an increase in temperature by heat exchange.

[0010] It may further include a design member disposed inside the lamp chamber and visible from the outside when looking at the front portion. The dew condensation member may be disposed between the extending portion and the upper edge portion of the design member. Thereby, it becomes difficult for the dew condensation member to be seen from the outside.

[0011] The dew condensation member may be disposed behind the tip of the upper edge portion of the design member. Thereby, it becomes even more difficult for the dew condensation member to be seen from the outside.

[0012] The dew condensation member may have an inclined surface that slopes downward from the front to the rear. Thereby, even if the released moisture condenses on the dew condensation member, the water droplets will drip backward, preventing them from dripping onto the front portion of the outer cover.

[0013] The outer cover may be made of polycarbonate resin or acrylic resin.

[0014] An anti-fog coating may be applied to the inner surface on the lamp chamber side of the outer cover. Thereby, the inner surface of the outer cover is less likely to fog up.

[0015] Any combination of the above components, and those obtained by converting the expression of the present invention among manufacturing methods, devices such as lamps and lighting, light-emitting modules, light sources, etc. are also effective as aspects of the present invention.

Effects of the Invention

[0016] According to the present invention, the appearance defect of the outer cover can be reduced.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0018] Hereinafter, the present invention will be described with reference to the drawings based on preferred embodiments. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. Also, the embodiments are illustrative and not restrictive of the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0019] FIG. 1 is a longitudinal sectional view schematically showing a vehicle lamp according to the present embodiment. The vehicle lamp 10 shown in FIG. 1 is a vehicle headlamp. The vehicle lamp 10 includes a lamp body 12 having a horizontally long opening formed in the front surface, and an outer cover 14 attached to the peripheral edge of the opening of the lamp body 12 so as to cover the horizontally long opening. The outer cover 14 forms a lamp chamber 16 by covering the opening of the lamp body 12. A lamp unit 18 is housed inside the lamp chamber 16. The lamp unit 18 is configured such that light emitted from a semiconductor light emitting element 20, which is a light source, is irradiated to the outside through the outer cover 14.

[0020] Inside the lamp chamber 16, an extension 22 as a design member and a condensation member 24 where moisture released from each component of the vehicle lamp condenses are further arranged. The outer cover 14 has a front portion 14a through which the light emitted from the semiconductor light-emitting element 20 passes, and an extension portion 14b that extends rearward from the upper portion of the front portion 14a. The outer cover 14 is a translucent resin member that transmits visible light and is made of, for example, polycarbonate resin or acrylic resin. Polycarbonate resin and acrylic resin are materials with relatively high water absorption. Note that an anti-fogging coating may be applied to the inner surface on the lamp chamber side of the outer cover 14. The anti-fogging coating is, for example, a material having hydrophilicity or water absorption. Specifically, for example, a material containing a surfactant in a block copolymer composed of a hydrophilic polymer portion and a hydrophobic polymer portion as disclosed in Japanese Patent Application No. 9-354981, and the ultraviolet absorption material may be a benzotriazole-based material. Thereby, the inner surface of the outer cover 14 is less likely to fog up.

[0021] When sunlight SL irradiates the front portion 14a of the outer cover 14 configured with the material as described above from the front in the early morning of summer when the sun altitude is low, the inside of the lamp chamber is warmed, and the moisture absorbed by each member is released. In particular, the moisture M released from the front portion 14a is directed toward the extension portion 14b at the upper part of the lamp chamber by the upward airflow A1 generated in the lamp chamber due to the warming of the outer cover 14. The extension portion 14b is a portion where the sunlight SL enters at an acute angle and may be hidden by the vehicle body, so it is less likely to warm up than the front portion 14a. Therefore, depending on the conditions, the temperature of the extension portion 14b may be about 20°C lower than the temperature of the front portion 14a. As a result, the moisture M moved by the upward airflow A1 is cooled and condensed on the inner surface of the extension portion 14b to form water droplets W1.

[0022] The water droplet W1 may run down along the inner surface of the outer cover 14 to the front portion 14a, leaving streak-like marks, which may cause a defect in the appearance of the outer cover 14. Therefore, the dew condensation member 24 according to the present embodiment is arranged so as to shield at least a part of the path along which the released moisture M travels toward the extension portion 14b. As a result, the moisture M that is released condenses on the dew condensation member 24 to form water droplets W2 before reaching the extension portion 14b, thereby reducing the amount of moisture that condenses on the extension portion 14b to form water droplets W1. As a result, the situation where the water droplets W1 that have condensed on the extension portion 14b drip down to the front portion 14a of the outer cover 14 is improved, and defects in the appearance of the outer cover 14 can be reduced.

[0023] Further, the dew condensation member 24 has an inclined surface 24a that slopes downward from the front to the rear. As a result, even if the released moisture M condenses on the dew condensation member 24 to form water droplets W2, the water droplets W2 drip backward, so that it is possible to prevent the water droplets from dripping down to the front portion 14a of the outer cover 14.

[0024] The extension 22 is inside the lamp chamber 16 and is arranged at a position where it can be visually recognized when looking at the front portion 14a from the outside. And the dew condensation member 24 is arranged between the extension portion 14b and the upper edge portion 22a of the extension 22. Thereby, it becomes difficult for the dew condensation member 24 to be seen from the outside. Further, the dew condensation member 24 according to the present embodiment is arranged behind the tip 22b of the upper edge portion 22a of the extension 22. Thereby, it becomes even more difficult for the dew condensation member 24 to be seen from the outside.

[0025] FIG. 2 is a schematic diagram for explaining the convection inside the lamp chamber during the running of the vehicle lamp according to the present embodiment. The vehicle lamp 10 further includes a heat radiating portion 26 that radiates the heat H emitted by the lamp unit 18. The heat radiating portion 26 is a heat sink having a plurality of fins, and the lamp unit 18 is cooled by the air A2 passing between the fins. The dew condensation member 24 is disposed above the heat radiating portion 26 and functions as a rectifying plate that causes the upward flow of the air A2 heated by the heat H radiated by the heat radiating portion to flow from the rear to the front. Thereby, the dew condensation member 24 cools the heat H radiated by the heat radiating portion 26 and becomes less likely to condense due to the increase in temperature by heat exchange.

[0026] The air A2 reaches the inner surface of the front portion 14a of the outer cover 14 after being cooled by the dew condensation member 24. Since the outer cover 14 is cooled by the running wind W during the running of the vehicle, it takes heat from the air A2 passing through the inner surface and discharges it to the outside. Thereby, the cooled air A2 flows downward along the inner surface of the front portion 14a, passes through the lower portion of the lamp chamber 16, reaches the heat radiating portion 26, and contributes again to the heat radiation at the heat radiating portion 26.

[0027] As described above, the present invention has been described with reference to the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and the present invention also includes those obtained by appropriately combining or replacing the configurations of the embodiments. In addition, it is possible to appropriately rearrange the combinations and processing orders in the embodiments based on the knowledge of those skilled in the art, and to add various design changes and other modifications to the embodiments. Embodiments to which such modifications are added may also be included in the scope of the present invention.

[0028] For example, the above-described vehicle lamp has been described assuming a vehicle headlamp provided at the front of the vehicle, but it can also be applied to a rear combination lamp provided at the rear of the vehicle.

Explanation of Reference Numerals

[0029] 10 Vehicle lamp, 12 Lamp body, 14 Outer cover, 14a Front part, 14b Extension part, 16 Lamp chamber, 18 Lamp unit, 20 Semiconductor light-emitting element, 22 Extension, 22a Upper edge part, 22b Tip, 24 Condensation member, 24a Inclined surface, 26 Heat dissipation part, A1 Upward air flow, A2 Air, W1 Water droplet, W2 Water droplet.

Claims

1. A lamp body, An outer cover that forms a lamp chamber by covering the opening of the lamp body, A lamp unit housed inside the lamp chamber, And a condensation member disposed inside the lamp chamber where the released moisture condenses, The outer cover has a front portion through which light emitted from the lamp unit passes, and an extension portion that extends rearward from the upper portion of the front portion, The condensation member is disposed so as to shield at least a part of the path along which the released moisture travels toward the extension portion. A vehicle lamp characterized by this.

2. Further comprising a heat dissipation portion that dissipates heat generated by the lamp unit, The condensation member is disposed above the heat dissipation portion and functions as a flow rectifying plate that causes the heat dissipated by the heat dissipation portion to flow from the rear to the front. The vehicle lamp according to claim 1, characterized by this.

3. Further comprising a design member disposed inside the lamp chamber and visible when the front portion is viewed from the outside, The condensation member is disposed between the extension portion and the upper edge portion of the design member. The vehicle lamp according to claim 1 or 2, characterized by this.

4. The condensation member is disposed behind the tip of the upper edge portion of the design member. The vehicle lamp according to claim 3, characterized by this.

5. The condensation member has an inclined surface that slopes downward from the front to the rear. The vehicle lamp according to claim 1 or 2, characterized by this.

6. The outer cover is made of polycarbonate resin or acrylic resin. The vehicle lamp according to claim 1 or 2, characterized by this.

7. The outer cover is coated with an anti-fogging coating on the inner surface on the lamp chamber side. The vehicle lamp according to claim 1 or 2, characterized by this.

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