Vehicle lamp

Abstract

To provide a vehicle lamp capable of extending a period until moisture absorption performance of a desiccant is saturated, while maintaining moisture absorption and release performance of a moisture absorption and release agent arranged inside a lamp body.SOLUTION: A vehicle lamp 1 has a lamp unit 5 that emits light forward and is arranged inside a lamp body 4 composed of a housing 2 with an open front and an outer lens 3 covering the opening of the housing 2, where a desiccant D and a moisture absorption and release agent M are separately arranged inside the lamp body 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] 2. Description of the Related Art Conventionally, there has been a vehicle lamp in which a lamp unit that irradiates light forward is disposed inside a lamp body composed of a housing with an opening at the front and an outer lens (cover lens) that covers the opening of the housing.

[0003] Such vehicle lighting fixtures have a structure in which components that constitute the lighting unit, such as a light source lamp (light source), an inner lens (light guide), a reflector, and an extension, are arranged inside the lamp body, and these components are attached to the inside of the lamp body.

[0004] In vehicle lighting, the air inside the lamp expands / contracts due to temperature changes caused by turning the lamp unit on / off, so ventilation (intake / exhaust) is performed through a ventilation hole (breathing hole) provided in the lamp.

[0005] On the other hand, in a vehicle lamp, when the outside air temperature drops below the temperature inside the lamp, moisture (water) inside the lamp may condense on the inner surface of the outer lens, causing the inner surface of the outer lens to become cloudy.

[0006] In addition, if condensation (clouding) occurs on the inner surface of the outer lens, not only will it deteriorate the appearance, but it will also reduce the transmittance of the light emitted forward from the lighting unit, resulting in a decrease in lamp functionality (especially illuminance).

[0007] In order to solve this problem, a desiccant (moisture absorbent) is placed inside the lamp body. However, since the desiccant (moisture absorbent) only absorbs moisture, once its moisture absorption capacity (absorption amount) is saturated, it becomes difficult to absorb any more moisture. In that case, it becomes necessary to replace the desiccant (moisture absorbent).

[0008] In response to this, it has been proposed to place a humidity-regulating sheet (moisture absorbing / releasing agent) inside the lamp body, so that when the humidity inside the lamp body is high, the humidity-regulating sheet quickly absorbs (absorbs) the moisture (water), and when the humidity inside the lamp body is low, the humidity-regulating sheet quickly releases (releasing) the moisture (water) it has absorbed, thereby allowing the humidity-regulating sheet (moisture absorbing / releasing agent) to be used continuously (without replacement) (see, for example, Patent Document 1 below). [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2008-159310 A Summary of the Invention [Problem to be solved by the invention]

[0010] Incidentally, although the above-mentioned humidity-regulating sheet (moisture absorbing / releasing agent) has better moisture absorption response than a desiccant (moisture absorbent), its moisture absorption rate (amount of moisture absorbed) is lower than that of a desiccant (moisture absorbent), and when the amount of moisture absorbed becomes saturated, the above-mentioned problems due to condensation occur.

[0011] On the other hand, the above-mentioned Patent Document 1 describes the use of a humidity conditioning sheet (moisture absorbing and releasing agent) mixed with a desiccant (moisture absorbing agent).

[0012] However, if a desiccant (moisture absorbent) is mixed into a humidity-conditioning sheet (moisture absorption and release agent), the moisture (water) released (released) from the humidity-conditioning sheet (moisture absorption and release agent) may be absorbed by the desiccant (moisture absorbent), which may shorten the period (lifespan) until the moisture absorption performance (absorption amount) of the desiccant (moisture absorbent) becomes saturated.

[0013] Furthermore, since desiccants expand when they absorb moisture, if a moisture absorbing / releasing agent and a desiccant are enclosed in a single moisture-permeable bag, the area of ​​the moisture absorbing / releasing agent's surface that comes into contact with the air will be reduced, which may hinder the moisture absorbing and releasing performance of the moisture absorbing / releasing agent.

[0014] The present invention has been proposed in consideration of the above-mentioned conventional circumstances, and has an object to provide a vehicle lamp that, when preventing the occurrence of condensation on the inner surface of the outer lens, makes it possible to extend the period until the moisture absorption performance of the desiccant becomes saturated while maintaining the moisture absorption and release performance of the moisture absorption and release agent placed inside the lamp body. [Means for solving the problem]

[0015] In order to achieve the above object, the present invention provides the following means. [1] A vehicle lamp having a lamp unit that irradiates light forward and is disposed inside a lamp body that is composed of a housing with an opening at the front and an outer lens that covers the opening of the housing, A vehicle lamp, characterized in that a desiccant and a moisture absorbing and releasing agent are separately disposed inside the lamp body. [2] The vehicle lamp according to [1], wherein the moisture absorbing and releasing agent has a moisture absorbing speed at least twice as fast as that of the desiccant. [3] The vehicle lamp according to [1], wherein the weight of the desiccant is equal to or greater than the weight of the moisture absorbing and releasing agent. [4] The vehicle lamp according to [1], wherein the moisture absorbing and releasing agent is disposed closer to the outer lens than the desiccant. Effect of the Invention

[0016] As described above, according to the present invention, a vehicle lamp is provided that, when preventing the occurrence of condensation on the inner surface of the outer lens, makes it possible to extend the period until the moisture absorption and release performance of the moisture absorption and release agent placed inside the lamp body is saturated while maintaining the moisture absorption and release performance of the moisture absorption and release agent placed inside the lamp body. [Brief description of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view showing a configuration of a vehicle lamp according to an embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view showing a configuration in which the arrangement of the moisture absorbing and releasing agent is changed in the vehicle lamp shown in FIG. 1. [Diagram 3]10 is a graph showing the results of measuring the relative humidity inside the lamp body when an acceleration test and a fogging test were performed on the boxes of Example 1 and Comparative Examples 1 and 2 in the first example. [Figure 4] 13 is a graph showing the results of measuring the relative humidity inside the lamp body when a usage cycle test was carried out on the boxes of Example 1 and Comparative Examples 1 and 3 in the second example. [Diagram 5] 13 is a graph showing the results of measuring the relative humidity inside the lamp body when a durability cycle test was carried out on the boxes of Example 1 and Comparative Example 1 in the third example. [Figure 6] 13 is a graph showing the results of measuring the relative humidity inside the lamp body when a fogging test was carried out on the boxes of Comparative Examples 2 and 3 in the fourth embodiment. [Figure 7] 13 is a graph showing the results of measuring the moisture absorption rates of a desiccant and a moisture absorbing and releasing agent in a fifth embodiment. [Figure 8] 13 is a graph showing the results of measuring the relative humidity inside the lighting body when an actual machine test was carried out on the boxes of Example 1 and Comparative Examples 1 and 3 in the sixth example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings used in the following description, in order to make each component easier to see, the dimensions of the components may be shown at different scales, and the dimensional ratios of each component may not necessarily be the same as in reality.

[0019] As an embodiment of the present invention, for example, a vehicle lamp 1 shown in FIG. 1 will be described. FIG. 1 is a cross-sectional view showing the configuration of a vehicle lamp 1. As shown in FIG.

[0020] In addition, in the drawings shown below, an XYZ Cartesian coordinate system is set up, with the X-axis direction representing the front-to-rear direction (length direction) of the vehicle lighting fixture 1, the Y-axis direction representing the left-to-right direction (width direction) of the vehicle lighting fixture 1, and the Z-axis direction representing the up-down direction (height direction) of the vehicle lighting fixture 1.

[0021] The vehicle lighting device 1 of this embodiment is an application of the present invention to a vehicle headlamp (headlamp) mounted, for example, on both corners of the front end of a vehicle (not shown) (in this embodiment, the corners on the left front end).

[0022] Specifically, as shown in FIG. 1, this vehicle lamp 1 has a structure in which a lamp unit 5 that emits light toward the front of the vehicle (in the +X-axis direction) is disposed inside a lamp body 4 composed of a housing 2 with an open front and a transparent outer lens (cover lens) 3 that covers the opening of the housing 2.

[0023] The lighting unit 5 includes, for example, a light source 6 that emits white light (hereinafter simply referred to as light) and a reflector 7 that reflects the light emitted from the light source 6, and is configured to irradiate the light reflected by the reflector 7 toward the front of the vehicle.

[0024] An extension 8 that covers the periphery of the front side of the reflector 7 (lamp unit 5) is disposed inside the lamp body 4. Furthermore, a bracket (not shown) for attaching the above-mentioned members to the inside of the lamp body 4 and the like are disposed inside the lamp body 4. The shape of the lamp body 4 can be appropriately changed according to the design of the vehicle lamp 1 and the like.

[0025] The lighting unit 5 is not necessarily limited to a configuration in which light reflected by the reflector 7 described above is irradiated toward the front of the vehicle, but may be configured, for example, to irradiate light emitted from the light source 6 toward the front of the vehicle using a light guide such as an inner lens (not shown).

[0026] For the light source 6, for example, a light source lamp such as a halogen lamp or an HID lamp can be used. In addition to the above-mentioned light source lamps, for example, a light emitting element such as a light emitting diode (LED) or a laser diode (LD) can be used. Furthermore, the number of light emitting elements is not limited to one, and may be multiple.

[0027] In the vehicle lamp 1 of this embodiment, the air inside the lamp body 4 expands / contracts due to temperature changes caused by turning the lamp unit 5 on / off, so ventilation (intake / exhaust) is performed through a ventilation opening (breathing hole) 9 provided on the back side of the housing 2 (lamp body 4).

[0028] On the other hand, in the vehicle lamp 1, if the outside air temperature drops below the temperature inside the lamp body 4, the moisture (water) inside the lamp body 4 may condense on the inner surface of the outer lens 3, causing the inner surface of the outer lens 3 to become cloudy.

[0029] In the vehicle lamp 1 of this embodiment, in order to prevent condensation (clouding) from occurring on the inner surface of the outer lens 3, a desiccant D and a moisture absorbing and releasing agent M are separately arranged inside the lamp body 4.

[0030] In this embodiment, a desiccant D is disposed on the inner surface of the lower housing 2 sandwiching the light source 6, located behind the reflector 7, and a moisture absorbing and releasing agent M is disposed on the inner surface of the upper housing 2 sandwiching the light source 6.

[0031] In addition, when the desiccant D and the moisture absorption / release agent M are placed on the inner surface of the housing 2, it is preferable to place the moisture absorption / release agent M, which has excellent moisture absorption response (moisture absorption speed), closer to the ventilation opening 9 than the desiccant D.

[0032] This allows the moisture absorbent / desorbent M to efficiently absorb (absorb) the moisture (water) contained in the air drawn in through the ventilation opening (breathing hole) 9, while also allowing the moisture absorbent / desorbent M to efficiently release (release) the moisture (water) absorbed (absorbed) into the air exhausted through the ventilation opening (breathing hole) 9.

[0033] The desiccant D may be any known desiccant that absorbs moisture (water) from within the lamp body 4. For example, magnesium chloride is used as the desiccant D in this embodiment.

[0034] The moisture absorbing and releasing agent M may be any agent that absorbs (absorbs moisture) or releases (desorbs moisture) moisture (water) inside the lamp body 4, and may be any agent that has been known in the art. For example, in this embodiment, a moisture absorbing and releasing polymer is used as the moisture absorbing and releasing agent M.

[0035] The moisture absorbing and releasing agent M has better moisture absorption response (moisture absorption speed) than the desiccant D, so when the humidity inside the lamp body 4 is high, the moisture absorbing and releasing agent M quickly absorbs (absorbs) moisture (water). On the other hand, when the humidity inside the lamp body 4 is low, the moisture absorbing and releasing agent M quickly releases (releases) the moisture (water) it has absorbed (absorbed). In addition, the moisture absorbing and releasing agent M can also respond to a sudden increase in humidity inside the lamp body 4.

[0036] In contrast, since the desiccant D has a higher moisture absorption rate (amount of moisture absorbed) than the moisture absorption and desorption agent M, when the humidity inside the lamp body 4 is high and the amount of moisture absorbed by the moisture absorption and desorption agent M becomes saturated, the desiccant D absorbs (absorbs) the moisture (moisture).

[0037] As a result, in the vehicle lamp 1 of this embodiment, it is possible to prevent condensation (fogging) from occurring on the inner surface of the outer lens 3.

[0038] In addition, in the vehicle lamp 1 of this embodiment, by separately arranging the desiccant D and the moisture absorption and release agent M inside the above-mentioned lamp body 4, it is possible to make it difficult for the moisture (water) released (desorbed) from the moisture absorption and release agent M to be absorbed by the desiccant D.

[0039] As a result, in the vehicle lamp 1 of this embodiment, it is possible to extend the period (life) until the moisture absorption performance (amount of moisture absorption) of the desiccant D becomes saturated.

[0040] Furthermore, in the vehicle lamp 1 of this embodiment, even after the moisture absorption performance (moisture absorption amount) of the desiccant D becomes saturated, the moisture absorption and release performance of the moisture absorption and release agent M is maintained, and the moisture (water) inside the lamp body 4 can be absorbed (absorbed) by the moisture absorption and release agent M.

[0041] In this embodiment, it is preferable that the moisture absorption rate of the moisture absorbing and releasing agent M is at least twice as high as that of the desiccant D. This allows the moisture (water) inside the light body 4 to be absorbed (absorbed) by the moisture absorbing and releasing agent M in preference to the desiccant D.

[0042] The weight of the desiccant D is preferably equal to or greater than the weight of the moisture absorption / release agent M. Specifically, the weight of the desiccant D is preferably greater than the weight of the moisture absorption / release agent M, and more preferably is at least twice as large. This makes it possible to sufficiently ensure the moisture absorption performance (moisture absorption amount) of the desiccant D.

[0043] In order to prevent condensation (clouding) on ​​the inner surface of the outer lens 3, it is preferable to place a moisture absorbing and releasing agent M, which has excellent moisture absorption response (moisture absorption speed), closer to the outer lens 3 than the desiccant D.

[0044] In this case, the moisture absorbing and releasing agent M may be arranged as shown in Fig. 2. Fig. 2 is a cross-sectional view showing a configuration in which the arrangement of the moisture absorbing and releasing agent M in the vehicle lamp 1 is changed.

[0045] 2, the moisture absorbing and releasing agent M is disposed on the inner lower surface of the outer lens 3, located closer to the front than the extension 8. This allows the moisture absorbing and releasing agent M to efficiently absorb (absorb) moisture near the inner surface of the outer lens 3.

[0046] The arrangement of the desiccant D and the moisture absorption / release agent M is not necessarily limited to the arrangement described above, and it is possible to arrange the desiccant D and the moisture absorption / release agent M separately in optimal locations according to the shape of the light body 4 and the position of the ventilation opening 9. It is also possible to optimize the arrangement by separately arranging the desiccant D and the moisture absorption / release agent M in multiple locations.

[0047] Moreover, when the moisture absorption performance (amount of moisture absorption) of the desiccant D becomes saturated, it is possible to replace it with a new desiccant D. In this case, it is preferable to place the desiccant D at a position in the light body 4 where it can be easily replaced (for example, on the inner surface of the rear side of the housing 2, etc.).

[0048] As described above, in the vehicle lamp 1 of this embodiment, when preventing the occurrence of condensation (fogging) on ​​the inner surface of the outer lens 3 described above, it is possible to extend the period (life) until the moisture absorption performance (moisture absorption amount) of the desiccant D becomes saturated while maintaining the moisture absorption and release performance of the moisture absorption and release agent M arranged inside the lamp body 4.

[0049] In the vehicle lamp 1 of this embodiment, when the moisture absorbing and releasing agent M releases (desorbs) the moisture (water) it has absorbed (absorbs), the humidity inside the lamp body 4 becomes relatively high, but since the humidity inside the lamp body 4 is in a low humidity state, there is almost no impact sufficient to cause condensation (clouding) on ​​the inner surface of the outer lens 3.

[0050] The present invention is not necessarily limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

[0051] For example, in the above embodiment, an example is given of the application of the present invention to a vehicle headlamp (headlamp), but the vehicle lamp to which the present invention can be applied is not limited to the front vehicle lamp described above, and the present invention can also be applied to a rear vehicle lamp such as a rear combination lamp. EXAMPLES

[0052] The effects of the present invention will be more clearly understood by the following examples. Note that the present invention is not limited to the following examples, and can be modified as appropriate without departing from the spirit and scope of the present invention.

[0053] (First embodiment) In the first embodiment, a box of embodiment 1 was prepared in which a desiccant and a moisture absorption / release agent were separately placed inside a box simulating a light body; a box of comparison example 1 in which only a desiccant was placed inside a box simulating a light body; and a box of comparison example 3 in which a desiccant and a moisture absorption / release agent were not placed inside the box simulating a light body.

[0054] Then, the boxes of Example 1 and Comparative Examples 1 and 3 were subjected to an accelerated test simulating the environment up to the delivery of a vehicle.

[0055] Before delivery, vehicles are stored for a relatively long time with the engine stopped during transportation or at the dealership. In this case, the moisture (water) absorption (moisture absorption) progresses inside the box. On the other hand, after delivery, the inside of the box is heated by the heat emitted from the engine, etc. while the vehicle is running, so the moisture (water) release (moisture release) starts inside the box. Therefore, before delivery, the vehicle lamp is in an environment where the moisture (water) absorption (moisture absorption) progresses inside the box.

[0056] The desiccant used was 30g of magnesium chloride. The desiccant's moisture absorption rate was 0.6% / day, and the moisture absorption rate at that time was over 50%. On the other hand, the moisture absorbent used was 15g of a moisture absorbing polymer. The moisture absorbent's moisture absorption rate was 8% / day, and the moisture absorption rate at that time was over 25%.

[0057] In the accelerated test, the boxes of Example 1 and Comparative Examples 1 and 3 were left in an environmental atmosphere with a temperature of 40° C. and a humidity of 90% for 100 hours or more. The relative humidity (%) in the box during that time was measured and the results are shown in the graph of FIG.

[0058] In addition, in an environmental atmosphere with a temperature of 40°C and a humidity of 90%, the moisture absorption rate of the desiccant after 100 hours was 2% / day, and the moisture absorption rate of the moisture absorption / release agent after 24 hours was 35%.

[0059] As a result, as shown in the graph of Fig. 3, it was confirmed that the boxes of Comparative Example 1 and Example 1 had a lower relative humidity than the box of Comparative Example 3. Furthermore, the box of Example 1 had a higher relative humidity from the start of the accelerated test than the box of Comparative Example 1, but showed a similar relative humidity to the box of Comparative Example 1 over time.

[0060] Next, after the above-mentioned accelerated test, a fogging test was conducted on the boxes of Example 1 and Comparative Examples 1 and 3 in which the temperature and humidity inside the box were increased and then the surface of the box was cooled to forcibly cause condensation (fogging) on ​​the inner surface of the box.

[0061] As a result, as shown in the graph of FIG. 3, the relative humidity in the box of Comparative Example 3 was higher than that in the boxes of Comparative Example 1 and Example 1, and condensation (clouding) occurred on the inner surface of the box.

[0062] From these test results, it was confirmed that the desiccant placed inside the lamp body was effective in preventing condensation (clouding) on ​​the inner surface of the lamp body.

[0063] On the other hand, in the fogging test, it was confirmed that the box of Example 1 had a lower relative humidity than the box of Comparative Example 1 in response to a sudden increase in humidity inside the box.

[0064] Therefore, from these test results, it was found that the box of Example 1 can keep the humidity inside the box lower than the boxes of Comparative Examples 1 and 3 in the accelerated test simulating the environment leading up to the delivery of the vehicle and the fogging test in which condensation (fogging) is forcibly generated on the inner surface of the box.

[0065] (Second Example) In the second embodiment, boxes of Example 1 and Comparative Examples 1 and 3 were prepared.

[0066] Then, the boxes of Example 1 and Comparative Examples 1 and 3 were subjected to a usage cycle test in which a high humidity (moisture absorption) state and a high temperature (moisture release) state were alternately repeated, simulating the usage environment of a vehicle.

[0067] In the use cycle test, the boxes of Example 1 and Comparative Examples 1 and 3 were left for 500 hours in an environmental atmosphere in which a high humidity (moisture absorption) state and a high temperature (moisture release) state were alternately repeated. The results of measuring the relative humidity (%) in the box during that time are shown in the graph of FIG.

[0068] As a result, as shown in the graph of FIG. 4, it was confirmed that the box of Example 1 had a lower relative humidity than the boxes of Comparative Examples 1 and 3.

[0069] Therefore, from the test results, it was found that the box of Example 1 was able to keep the humidity inside the box lower than the boxes of Comparative Examples 1 and 3 in the usage cycle test simulating the usage environment of a vehicle.

[0070] (Third Example) In the third example, the boxes of Example 1 and Comparative Example 1 were prepared.

[0071] Then, for the boxes of Example 1 and Comparative Example 1, a durability cycle test was conducted in which a high humidity (moisture absorption) state simulating a state (end of life) in which the moisture absorption performance (absorption amount) of the desiccant is saturated and a high temperature (moisture release) state were alternately repeated.

[0072] In order to reproduce the state where the moisture absorption performance (absorption amount) of the desiccant is saturated, the test conditions were set to an environmental atmosphere of 40°C temperature and 90% humidity, and a desiccant with a moisture absorption rate of 1.2% / day after 720 hours was used. Other than that, the test conditions were the same as those of the second embodiment.

[0073] In the durability cycle test, the boxes of Example 1 and Comparative Example 1 were left for 500 hours in an environmental atmosphere in which a high humidity (moisture absorption) state and a high temperature (moisture release) state were alternately repeated. The results of measuring the relative humidity (%) in the box during that time are shown in the graph of FIG.

[0074] As a result, as shown in the graph of FIG. 5, it was confirmed that the box of Example 1 had a lower relative humidity than the box of Comparative Example 1.

[0075] Therefore, these test results show that the box of Example 1 can keep the humidity inside the box lower than that of the box of Comparison Example 1 in a durability cycle test simulating a state in which the moisture absorption performance (absorption amount) of the desiccant is saturated (end of life).

[0076] (Fourth Example) In the fourth embodiment, boxes of Comparative Example 2 and Comparative Example 3 were prepared in which only a moisture absorbing and releasing agent was placed in a box simulating a lamp body.

[0077] Then, for the boxes of Comparative Examples 2 and 3, in order to reproduce the state after the moisture absorption performance (absorption amount) of the desiccant has reached saturation, the humidity inside the box was conditioned for more than 24 hours in an environmental atmosphere with a temperature of 23°C and a humidity of 55%.

[0078] After that, the temperature and humidity inside the box were increased, and then the surface of the box was cooled to forcibly cause condensation (fog) on ​​the inside of the box, in a fogging test. The results of measuring the relative humidity (%) inside the box during this test are shown in the graph in Figure 6.

[0079] The test conditions were an environmental atmosphere of 40°C temperature and 90% humidity, and a moisture absorbing and releasing agent with a moisture absorption rate of 30% after 24 hours was used. The other conditions were the same as those in the first embodiment.

[0080] As a result, as shown in the graph of FIG. 6, it was confirmed that the box of Comparative Example 2 always had a lower relative humidity than the box of Comparative Example 3 during the fogging test.

[0081] Therefore, from the test results, it was found that even after the moisture absorption performance (absorption amount) of the desiccant was saturated, the moisture absorption by the moisture absorbing and releasing agent could provide the effect of preventing fogging of the outer lens.

[0082] (Fifth Example) In the fifth embodiment, boxes of Comparative Example 1 and Comparative Example 2 were prepared.

[0083] A test was then carried out to measure the moisture absorption rate of the boxes of Comparative Examples 1 and 2. The measurement results are shown in the graph of FIG.

[0084] As a result, as shown in the graph of FIG. 7, the box of Comparative Example 2 had a higher moisture absorption rate from the start of the test compared to the box of Comparative Example 1, but after the moisture absorption and release agent reached saturation, the moisture absorption rate of the box of Comparative Example 1 became higher over time compared to the box of Comparative Example 2.

[0085] Therefore, from the test results, it was found that although the moisture absorbing / releasing agent has a better moisture absorption response (moisture absorption speed) than the desiccant, the desiccant has a better moisture absorption rate (amount of moisture absorbed) than the moisture absorbing / releasing agent.

[0086] If one were to obtain the same moisture absorption performance (amount of moisture absorbed) as a desiccant using only a moisture absorbent, the moisture absorbent would need to weigh about four times as much as the desiccant. In this case, it would be difficult to place the necessary amount of moisture absorbent in the lamp, and costs would also increase.

[0087] (Sixth Example) In the sixth embodiment, boxes of Example 1, Comparative Example 1, and Comparative Example 3 were prepared.

[0088] Then, an actual test was carried out by mounting the boxes of Example 1 and Comparative Examples 1 and 3 on a vehicle. The results of measuring the relative humidity (%) in the box during the test are shown in the graph of FIG.

[0089] As a result, as shown in the graph of FIG. 8, it was confirmed that the box of Example 1 had a lower relative humidity than the boxes of Comparative Examples 1 and 3.

[0090] Therefore, from the test results, it was found that the box of Example 1 was able to keep the humidity inside the box lower than the boxes of Comparative Examples 1 and 3 in the actual machine test mounted on a vehicle.

[0091] 8, the box of Example 1 sometimes had a higher relative humidity than the box of Comparative Example 1. This is thought to be due to the effect of moisture release from the moisture absorbing and releasing agent, but it was confirmed that the relative humidity inside the box was low and not at a level that would cause condensation (cloudiness) on the inner surface of the box.

[0092] In this embodiment, in addition to the desiccants and moisture absorbing / releasing agents exemplified in the first to fifth embodiments described above, for example, the desiccants and moisture absorbing / releasing agents exemplified below can be suitably used.

[0093] A desiccant with a moisture absorption rate of 0.6% / day or more after 720 hours in an environmental atmosphere with a temperature of 40°C and a humidity of 90%. A desiccant that has a moisture absorption rate of 0.6% / day in an environmental atmosphere with a temperature of 40°C and humidity of 90%, and at that point, the moisture absorption rate is 80% or more. A desiccant with a moisture absorption rate of 1.8% / day or more after 100 hours in an environmental atmosphere with a temperature of 40°C and a humidity of 90%. A moisture absorption / release agent that has a moisture absorption rate of 25% or more after 24 hours in an environmental atmosphere with a temperature of 23°C and a humidity of 55%, and then after 24 hours in an environmental atmosphere with a temperature of 40°C and a humidity of 90%. A moisture absorber that has a moisture release rate of 15% or less after 24 hours in an environmental atmosphere with a temperature of 23°C and a humidity of 55%, and then after 24 hours in an environmental atmosphere with a temperature of 10°C and a humidity of 50%. A desiccant with a moisture absorption rate of 0.6~6% / day after 720 hours in an environmental atmosphere with a temperature of 40℃ and humidity of 90%. A desiccant with a moisture absorption rate of 0.6% / day in an environmental atmosphere with a temperature of 40℃ and humidity of 90%, and a moisture absorption rate of 50-300% at that point. A desiccant with a moisture absorption rate of 1.8~30% / day after 100 hours in an environmental atmosphere with a temperature of 40℃ and humidity of 90%. A desiccant with a moisture absorption rate of 1% / day or more after 100 hours in an environmental atmosphere with a temperature of 40°C and a humidity of 90%. A desiccant that has a moisture absorption rate of 1% / day in an environmental atmosphere with a temperature of 40°C and humidity of 90%, and whose moisture absorption rate at that point is 40% or more. [Explanation of symbols]

[0094] REFERENCE SIGNS LIST 1...vehicle lamp 2...housing 3...outer lens 4...lamp body 5...lamp unit 6...light source 7...reflector 8...extension 9...ventilation port D...desiccant M...moisture absorbing / releasing agent

Claims

1. A vehicle lamp including a lamp unit that irradiates light forward and is disposed inside a lamp body that is composed of a housing with an opening at the front and an outer lens that covers the opening of the housing, A vehicle lamp, characterized in that a desiccant and a moisture absorbing and releasing agent are separately disposed inside the lamp body.

2. 2. The vehicle lamp according to claim 1, wherein the moisture absorbing and releasing agent has a moisture absorbing speed at least twice as fast as that of the desiccant.

3. 2. The vehicle lamp according to claim 1, wherein the weight of the desiccant is equal to or greater than the weight of the moisture absorbing and releasing agent.

4. 2. The vehicle lamp according to claim 1, wherein the moisture absorbing and releasing agent is disposed closer to the outer lens than the desiccant.

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