Optical device

Abstract

A light source unit (2) emits light. An outer cover (3) transmits the light. A housing (4) forms, with the outer cover (3), a lamp chamber (S) in which the light source unit (2) is housed. A humidity adjustment mechanism (5) is housed in the lamp chamber (S) and adjusts the humidity in the lamp chamber (S). In the housing (4), a breathing hole (6) by which the inside and outside of the lamp chamber (S) communicate with each other is formed. The moisture transmission rate from the inside to the outside of the lamp chamber (S) is set to 40 mg / h or less by the breathing hole (6).

Description

optical device

[0001] The present disclosure relates to optical devices.

[0002] Patent Document 1 discloses a vehicle lamp having a ventilation hole that allows air inside the lamp chamber formed by the outer cover and the housing to flow out to the outside or air from the outside to flow into the lamp chamber. This ventilation hole allows ventilation inside the lamp chamber and reduces the pressure difference between the inside and outside of the lamp chamber.

[0003] Japanese Patent Application Publication No. 2019-46788

[0004] Meanwhile, methods to prevent fogging on the inside of the outer cover have been studied. For example, it is conceivable to adjust the humidity inside the lamp chamber using a humidity control mechanism, but since moist air from the outside flows into the lamp chamber through the ventilation holes, the humidity control mechanism needs to be operated frequently.

[0005] An object of the present disclosure is to provide an optical device that suppresses fogging on the inside of an outer cover while reducing power consumption by a humidity control mechanism.

[0006] An optical device according to one aspect of the present disclosure comprises: an optical component that emits or admits light; an outer cover that transmits the light; a housing that, together with the outer cover, forms a storage space in which the optical component is housed; and a humidity control mechanism that is housed in the storage space and adjusts the humidity within the storage space, wherein at least one of the outer cover and the housing is formed with at least one breathing hole that connects the inside and outside of the storage space, and the at least one breathing hole allows moisture to pass through the storage space to the outside at a rate of 40 mg / h or less.

[0007] According to the present disclosure, it is possible to provide an optical device that suppresses fogging on the inside of the outer cover while reducing power consumption by the humidity control mechanism.

[0008] 1 illustrates a configuration of a vehicle lamp according to an embodiment of the present disclosure; FIG. 2 illustrates the ventilation hole of FIG. 1; FIG. 3 illustrates the ventilation hole of FIG. 1 as viewed from the rear of the vehicle lamp; FIG. 4 illustrates another example of the ventilation hole; FIG. 5 illustrates another example of the ventilation hole; FIG. 6 illustrates another example of the ventilation hole;

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component. In the drawings, arrow U indicates the upward direction of the illustrated structure. Arrow D indicates the downward direction of the illustrated structure. Arrow F indicates the forward direction of the illustrated structure. Arrow B indicates the rearward direction of the illustrated structure. Arrow R indicates the rightward direction of the illustrated structure. Arrow L indicates the leftward direction of the illustrated structure. These directions are relative directions set with the light emission direction of the vehicular lamp 1 illustrated in FIG. 1 as the forward direction.

[0010] 1 is a schematic diagram illustrating the configuration of a vehicle lamp 1 according to an embodiment of the present disclosure. The vehicle lamp 1 is provided, for example, at the front of a vehicle and constitutes a headlamp that irradiates light ahead of the vehicle.

[0011] The vehicle lamp 1 includes a light source unit 2, an outer cover 3, a housing 4, and a humidity control mechanism 5. The outer cover 3 is arranged to close the opening of the housing 4 from the front. The outer cover 3 and the housing 4 form a lamp chamber S. The vehicle lamp 1 is an example of an optical device. The light source unit 2 is an example of an optical component. The lamp chamber S is an example of an accommodation space.

[0012] The light source unit 2 is housed in the lamp chamber S. The light source unit 2 has a light source 21 and a lens 22. The lens 22 directs the light emitted from the light source 21 toward the front of the lamp. The light emitted from the light source unit 2 passes through the outer cover 3 and is irradiated toward the front of the vehicle.

[0013] The humidity control mechanism 5 is configured to be able to adjust the humidity inside the lamp chamber S. The humidity control mechanism 5 has a moisture absorbing member 51 and a heater 52. The moisture absorbing member 51 is a member that can absorb moisture in the air. The moisture absorbing member 51 is also a member that releases absorbed moisture into the air when heated to a high temperature of, for example, about 150°C. For example, the moisture absorbing member 51 can be made of silica gel, zeolite, a polymeric moisture absorbent, or the like. The heater 52 heats the moisture absorbing member 51.

[0014] In this example, the humidity control mechanism 5 has a partition wall 53 and a partition plate 54. The partition wall 53 places the moisture absorbent member 51 and the heater 52 in a second space S2 that is different from the first space S1 in which the light source unit 2 is placed. The partition plate 54 is configured to be movable between a position that covers the opening 41 formed in the housing 4 and a position that covers the opening 531 formed in the partition wall 53.

[0015] When the partition plate 54 is in a position covering the opening 41, the first space S1 and the second space S2 communicate with each other, and the moisture absorbent member 51 absorbs moisture inside the lamp chamber S. When the partition plate 54 is moved to a position covering the opening 531, the second space S2 communicates with the outside of the lamp chamber S. When the moisture absorbent member 51 is heated by the heater 52, the moisture contained in the moisture absorbent member 51 is released to the outside.

[0016] The housing 4 is formed with a ventilation hole 6 that connects the inside of the lamp chamber S with the outside. Air inside the lamp chamber S flows out to the outside via the ventilation hole 6, and air flows from the outside of the lamp chamber S into the lamp chamber S. In other words, the ventilation hole 6 ventilates the inside of the lamp chamber S. The ventilation hole 6 also reduces the pressure difference between the inside and outside of the lamp chamber S.

[0017] The ventilation holes 6 are formed so that the moisture transmission rate from the inside to the outside of the lamp chamber S is 40 mg / h or less, preferably 10 mg / h or less.

[0018] The term "moisture permeation rate" used in this specification refers to a value calculated from the change in humidity inside the lamp chamber S one hour after the start of measurement, when the temperature inside the lamp chamber S is 25 degrees and the humidity is 50%, and the temperature outside the lamp chamber S is 60 degrees and the humidity is 95%, and is expressed as the amount of moisture movement [mg / h].

[0019] In the vehicle lamp 1, if the surface temperature of the outer cover 3 drops suddenly due to rainfall, radiative cooling, or the like, and the humidity in the lamp chamber S increases, fogging may occur on the inside of the outer cover 3. In this case, it becomes difficult to irradiate the light emitted from the light source unit 2 with the desired intensity at the desired location. For this reason, the humidity in the lamp chamber S is regulated by the humidity control mechanism 5. However, the breathing hole 6, which is generally intended to ventilate the interior of the lamp chamber S, has a diameter of, for example, about 10 mm, and has a high moisture permeation rate, requiring frequent operation of the humidity control mechanism 5 (partition plate 54 and heater 52).

[0020] In contrast, in the vehicle lamp 1 according to the present disclosure, the moisture permeation rate through the breathing hole 6 is 40 mg / h or less. Therefore, even if the humidity control mechanism 5 is not operated frequently, a sudden increase in humidity inside the lamp chamber S due to air flowing in from outside the lamp chamber S can be suppressed. In other words, since the number of times the humidity control mechanism 5 is operated can be reduced, it is possible to suppress the occurrence of fogging on the inside of the outer cover 3 while suppressing power consumption by the humidity control mechanism 5. Note that when a typical vehicle lamp has a breathing hole with a diameter of 10 mm penetrating the housing (thickness 10 mm), the moisture permeation rate is approximately 330 mg / h.

[0021] As illustrated in Figures 2 and 3, the ventilation hole 6 preferably has a circular opening and is formed so that the ratio (D / L) of the flow path length L to the opening diameter D is 1 or less. The flow path length L refers to the length of the path through the ventilation hole 6 through which air flows. In this example, as shown in Figure 2, the ventilation hole 6 extends in the thickness direction of the housing 4 (the front-to-rear direction in Figure 2), and the flow path length L of the ventilation hole 6 is the same as the depth of the ventilation hole 6 (the length in the front-to-rear direction in Figure 2).

[0022] Table 1 shows the moisture permeation rate values ​​when the opening diameter D of the breathing hole 6 and the flow path length L are changed in the vehicle lamp 1. Table 1 also shows an evaluation of the workability of the breathing hole 6 and the pressure adjustment (internal pressure adjustment) inside and outside the lamp chamber S by the breathing hole 6.

[0023] The evaluation of processability was given as A if machining using a general mold was easy, as B if machining using a general mold was somewhat difficult, and as C if machining using a general mold was difficult. Note that no samples were given a C rating in the evaluation of processability. Furthermore, the evaluation of internal pressure adjustment was given as A if a flow rate of 100 cc / min or more could be ensured when a pressure of 1.2 atm was applied, as B if a flow rate of 50 cc / min or more could be ensured, and as C if internal pressure adjustment was not possible. Note that no samples were given a B rating in the evaluation of internal pressure adjustment.

[0024]

[0025] From the evaluation results in Table 1, the inventors have found that when the diameter D of the breathing hole 6 is relatively small (for example, D<10 mm), the smaller the ratio of the flow path length L to the opening diameter D of the breathing hole 6, the lower the moisture permeation rate through the breathing hole 6. Specifically, it has been found that by forming the breathing hole 6 so that the ratio of the flow path length L to the opening diameter D of the breathing hole 6 is 1 or less, the moisture permeation rate through the breathing hole 6 becomes 40 mg / h or less.

[0026] Furthermore, although Table 1 does not include samples with a diameter D of 0.5 mm or less, even when the opening diameter D of the breathing hole 6 is 0.5 mm, machining using a general mold is possible and pressure adjustment between the inside and outside of the lamp chamber S is possible. Furthermore, if the opening diameter D is 0.3 mm or more, machining using a general mold is possible and pressure adjustment between the inside and outside of the lamp chamber S is possible. In other words, from the perspective of machining using a general mold and adjusting the pressure between the inside and outside of the lamp chamber S, it is preferable that the opening diameter D of the breathing hole 6 be 0.3 mm or more, and preferably 0.5 mm or more.

[0027] In this embodiment, the breathing hole 6 is not limited to the configuration illustrated in Fig. 2. For example, as shown in Fig. 4, the breathing hole 6 may be formed so as to penetrate a thick portion 42 of the housing 4 that is thicker than other portions. By forming the breathing hole 6 in the thick portion 42 in this way, the depth of the breathing hole 6 can be made deep, i.e., the flow path length L can be made long, even if the thickness of the housing 4 is small.

[0028] Alternatively, the ventilation hole 6 may be formed so that the flow path length L is longer than the depth of the ventilation hole 6. For example, the ventilation hole 6 may be formed in a stepped shape as shown in Fig. 5, or in a spiral shape as shown in Fig. 6. With this configuration, the ventilation hole 6 can be formed with a desired flow path length L regardless of the thickness of the housing 4.

[0029] 7, a plurality of breathing holes 6 may be provided. With such a configuration, even if the opening diameter D of each breathing hole 6 is small, ventilation and pressure adjustment inside and outside the lamp chamber S can be sufficiently achieved through the breathing holes 6. Although two breathing holes 6 are provided in this example, three or more breathing holes 6 may be provided. Furthermore, the breathing holes 6 may have different shapes.

[0030] Furthermore, the opening of the ventilation hole 6 may be formed in an elliptical or rectangular shape instead of the circular shape shown in FIG.

[0031] Although the embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be construed as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and its equivalents.

[0032] The breathing holes 6 may be provided in the outer cover 3 instead of or in addition to the housing 4. That is, it is sufficient that the breathing holes 6 are provided in at least one of the outer cover 3 and the housing 4.

[0033] The humidity control mechanism 5 is not limited to the configuration shown in Fig. 1. For example, the humidity control mechanism 5 may be housed in the lamp chamber S, and a portion of the humidity control mechanism 5 may be incorporated into the housing 4. That is, a portion of the humidity control mechanism 5 may constitute a portion of the housing 4. In this case, the breathing hole 6 may be provided in the portion of the humidity control mechanism 5 that constitutes the housing 4.

[0034] The vehicular lamp 1 is not limited to a headlamp having the configuration shown in FIG. 1 . For example, the vehicular lamp 1 may be a fog lamp or a rear lamp. Alternatively, the vehicular lamp 1 may be configured to arrange lamps with multiple different functions in the lamp chamber S, rather than a lamp with a single function arranged in the lamp chamber S. For example, the vehicular lamp 1 may be a rear combination lamp having a stop lamp and a turn signal lamp. Furthermore, the vehicular lamp 1 may be a sensor-equipped vehicular lamp having, in the lamp chamber S, one or more lamps with multiple functions, as well as a sensor such as a camera, radar, LiDAR, or gating camera that acquires information about the surroundings of the vehicle.

[0035] In the above description, the vehicle lamp 1 is cited as an example of an optical device. However, lamps such as infrastructure lamps, such as street lamps, and lamps for moving objects, such as ships and railways, can also be examples of optical devices. Furthermore, optical devices are not limited to lamps, and sensor units having sensors, such as cameras, radars, LiDARs, and gating cameras, as optical components can also be examples of optical devices.

[0036] This application is based on Japanese Patent Application No. 2021-189569, filed on November 22, 2021, the contents of which are incorporated herein by reference.

Claims

1. an optical component for emitting or receiving light; an outer cover that transmits the light; a housing that, together with the outer cover, forms an accommodation space in which the optical component is accommodated; a humidity control mechanism accommodated in the accommodation space and regulating humidity within the accommodation space; It is equipped with At least one of the outer cover and the housing is formed with at least one ventilation hole that communicates between the inside and the outside of the accommodation space, An optical device, wherein the moisture permeation rate from the inside of the accommodation space to the outside is 40 mg / h or less through at least one of the breathing holes.

2. the optical component includes a light source that emits the light, The optical device according to claim 1 , wherein the optical device is a lighting fixture that irradiates light emitted from the light source to the outside.

3. 3. The optical device according to claim 1, wherein a ratio of a flow path length of the breathing hole to a diameter of the opening of the breathing hole is 1 or less.

4. The optical device of claim 3 , wherein the diameter of the aperture is 0.3 mm or greater.

5. 3. The optical device according to claim 1, wherein a plurality of the ventilation holes are provided.

6. 3. The optical device according to claim 1, wherein the ventilation hole penetrates a thick portion of at least one of the outer cover and the housing, the thick portion being thicker than other portions.