Vehicular head lamp

Abstract

To provide a vehicular head lamp which can remove fog on an outer lens without a heater.SOLUTION: A vehicular head lamp 10 includes a housing 70, an outer lens attached to the housing and forming a lamp room S1 between the outer lens and the housing, a lamp unit 20 which is disposed within the lamp room and emits visible light passing through a visible light transmission area A1 of the outer lens, and a defogging device 30 which is disposed within the lamp room and emits infrared light illuminating the visible light transmission area of the outer lens.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a vehicle headlamp. [Background technology]

[0002] 2. Description of the Related Art There is known a vehicle lamp that removes fogging on an outer lens by providing a line heater in a lamp chamber formed between a housing and an outer lens attached thereto (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-21601 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the vehicle lamp described in Patent Document 1 has a problem in that the line heater causes the inside of the lamp chamber to become hotter than necessary.

[0005] The present disclosure has been made to solve such problems, and has an object to provide a vehicle headlamp that can remove fogging that has adhered to the outer lens without using a heater. [Means for solving the problem]

[0006] The vehicle headlamp according to the present disclosure includes a housing, an outer lens attached to the housing to form a lamp chamber between the housing and the outer lens, a lamp unit disposed within the lamp chamber and emitting visible light that passes through the visible light transmission region of the outer lens, and an anti-fogging device disposed within the lamp chamber and emitting infrared light that irradiates the visible light transmission region of the outer lens.

[0007] With this configuration, the fogging on the outer lens 71 can be removed without using a heater.

[0008] This is due to the inclusion of an anti-fog device that emits infrared light that illuminates the visible light transmitting region of the outer lens.

[0009] In the above-mentioned vehicle headlamp, the anti-fogging device may include a semiconductor light-emitting element that emits infrared light of a wavelength belonging to the infrared region of the solar blind band, and an optical deflection element, and the optical deflection element may be configured to deflect the infrared light emitted from the semiconductor light-emitting element and incident on the optical deflection element, and the deflected infrared light may irradiate the visible light transmitting region of the outer lens.

[0010] In addition, the above-mentioned vehicle headlamp may further include a fogging detection unit that executes a fogging detection process to detect fogging adhering to the outer lens, and the anti-fogging device may emit infrared light to irradiate the visible light transmitting area of ​​the outer lens when the fogging is detected, and may not emit infrared light when the fogging is not detected.

[0011] In the vehicle headlamp, the infrared light may have a wavelength selected from the group consisting of 895 nm to 915 nm and 1350 nm to 1560 nm.

[0012] In addition, the above-mentioned vehicle headlamp may further include a bracket to which the lamp unit is attached, and an optical axis adjustment mechanism that adjusts the optical axis of the lamp unit by tilting the bracket, and the anti-fogging device may be attached to the bracket. Effect of the Invention

[0013] The present disclosure makes it possible to provide a vehicle headlamp that can remove fogging that has adhered to an outer lens without using a heater. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic configuration diagram of a vehicle lighting system 1 including a vehicle headlamp 10 according to an embodiment. [Diagram 2] FIG. 1 is a front view of a vehicle V on which a vehicle lighting system 1 is mounted. [Diagram 3] 3 is a cross-sectional view taken along line AA in FIG. 2. [Figure 4] This is an example of a low beam light distribution pattern PLo formed on a virtual vertical screen (located approximately 25 m forward from the front of the vehicle) facing directly in front of the vehicle. [Diagram 5] FIG. 5(a) is a schematic diagram of an anti-fogging device 30, and FIG. 5(b) is a cross-sectional view taken along line BB of FIG. 5(a). [Figure 6] 4 is a flowchart of an operation example of the vehicle lighting system 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a vehicle headlamp 10 according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. In each drawing, corresponding components are given the same reference numerals, and duplicated explanations will be omitted.

[0016] FIG. 1 is a schematic configuration diagram of a vehicle lighting system 1 including a vehicle headlamp 10 according to an embodiment.

[0017] As shown in Fig. 1, the vehicle lighting system 1 includes vehicle headlights 10 (10L, 10R) and a control device 60. The vehicle lighting system 1 is mounted on a vehicle V such as an automobile.

[0018] FIG. 2 is a front view of a vehicle V on which the vehicle lighting system 1 is mounted.

[0019] As shown in FIG. 2, the vehicle headlights 10 (10L, 10R) are provided on both the left and right sides of the front end of the vehicle V.

[0020] FIG. 3 is a cross-sectional view taken along line AA of FIG.

[0021] 1 and 3, a vehicle headlamp 10 includes a lamp unit 20 and an anti-fogging device 30. The lamp unit 20 and the anti-fogging device 30 are disposed in a lamp chamber S1 formed between a housing 70 and an outer lens 71 attached thereto.

[0022] First, a description will be given of a configuration example of the lighting unit 20. Below, a description will be given of an example in which the lighting unit 20 is a projector type lighting unit.

[0023] As shown in FIG. 3, the lamp unit 20 includes a semiconductor light emitting element 21, a reflecting surface 22 (reflector), a projection lens 23, a reflecting surface 24 (shade / mirror), a bracket 25, an optical axis adjustment mechanism 26, and an extension 27.

[0024] The semiconductor light emitting element 21 is, for example, a white LED light source. The white LED light source has a light emitting surface (for example, 1 mm square). The semiconductor light emitting element 21 is aligned with the first focal point F1 of the reflecting surface 22 when the light emitting surface faces upward. 22 is located nearby.

[0025] The reflecting surface 22 is an ellipsoidal reflecting surface, and has a first focal point F1 on the rear side of the vehicle. 22 , the second focus F2 on the front side of the vehicle 22 The reflective surface 22 is disposed in a state of covering the semiconductor light emitting element 21 (light emitting surface) so that the light emitted from the semiconductor light emitting element 21 is incident on the reflective surface 22.

[0026] The projection lens 23 has a focal point F 23 (rear focal point) is the second focal point F2 of the reflecting surface 22 22 The projection lens 23 projects light reflected from the reflecting surface 22 to a focal point F 23 The light source image formed on the focal plane including the above is inverted and projected forward of the vehicle.

[0027] The reflecting surface 24 (which doubles as a shade and mirror) is located at the focal point F of the projection lens 23. 25The reflecting surface 24 is a flat reflective surface that includes a front edge disposed nearby and extends horizontally from the front edge toward the rear of the vehicle (the semiconductor light emitting element 21 side). The front edge of the reflecting surface 24 includes a cutoff shape (Z-shaped step portion) (not shown) that corresponds to the cutoff line that is the upper edge of the light distribution pattern for low beam.

[0028] The semiconductor light emitting element 21 , the reflecting surface 22 , the projection lens 23 , and the reflecting surface 24 (which also serves as a shade and mirror) configured as above are attached to a bracket 25 .

[0029] The bracket 25 is attached to the housing 70 in a state in which it can tilt up, down, left, and right. On the other hand, the optical axis adjustment mechanism 26 is, for example, an aiming screw, which is rotatably attached to the housing 70 at the same position. The tip of the aiming screw is screwed into the bracket 25. Therefore, by rotating the aiming screw and adjusting the amount of screwing of the aiming screw into the bracket 25, the bracket 25 tilts up, down, left, and right in accordance with the amount of screwing. This allows the optical axis adjustment (for example, leveling) of the lamp unit 20 to be performed.

[0030] In the vehicle headlamp 10 having the above-described configuration, the semiconductor light emitting element 21 is turned on to generate a low beam light distribution pattern P Lo FIG. 4 shows a low-beam light distribution pattern P formed on a virtual vertical screen (located approximately 25 m ahead of the vehicle) facing the front of the vehicle. Lo This is an example.

[0031] In the lamp unit 20 having the above-mentioned configuration, when the semiconductor light-emitting element 21 is turned on, the light emitted by the semiconductor light-emitting element 21 is reflected by the reflecting surface 22 and reaches the focal point F of the projection lens 23. 23 The optical axis AX of the projection lens 23 23 The light is then focused toward the front and emitted from the projection lens 23 together with the reflected light that is further reflected (back-reflected) by the reflecting surface 24 (shade / mirror), and passes through the visible light transmitting area A1 (see FIG. 3) of the outer lens 71 to be irradiated forward.

[0032] The light (visible light) that is transmitted through the outer lens 71 (visible light transmitting region A1) and irradiated forward forms a low beam light distribution pattern P Lo This low beam light distribution pattern P Lo In this case, the areas in the vicinity of the cutoff line CL and in the vicinity of the intersection of the H line and the V line are relatively bright, providing excellent distant visibility.

[0033] The visible light transmission area A1 refers to an area of ​​the outer lens 71 through which the light emitted from the lamp unit 20 passes. The light emitted from the lamp unit 20 in the outer lens 71 is reflected by the low beam light distribution pattern P Lo 4) (see the area indicated by the symbol a1 in FIG. 4), or Lo 4. The light may be for forming a part of the high luminous intensity region a2 in FIG. 4, where the luminous intensity is relatively high.

[0034] Next, a configuration example of the defrosting device 30 will be described.

[0035] In the vehicle headlamp 10 configured as described above, when the outer lens 71 is cooled by rain or the like, condensation occurs and the inside of the outer lens 71 becomes foggy. When the inside of the outer lens 71 becomes foggy, the amount of light (visible light) emitted from the lamp unit 20 that passes through the outer lens 71 (visible light transmission area A1) decreases, so it is desirable to remove the fog that has adhered to the inside of the outer lens 71. The anti-fogging device 30 is used to remove the fog that has adhered to the inside of the outer lens 71.

[0036] FIG. 5(a) is a schematic diagram of the antifogging device 30, and FIG. 5(b) is a cross-sectional view taken along line BB of FIG. 5(a).

[0037] 5(a) and 5(b), the anti-fogging device 30 includes a light source module 31 and a light receiving module 32. The light source module 31 and the light receiving module 32 are housed in a housing 33 having a light-shielding property.

[0038] The light source module 31 emits infrared light of a wavelength belonging to the infrared region of the solar blind band (a wavelength region that is absorbed by water droplets and promotes evaporation) to a measurement target area in front of the vehicle V. The infrared region of the solar blind band is, for example, 895 nm to 915 nm and 1350 nm to 1560 nm. The wavelength belonging to the infrared region of the solar blind band is a wavelength selected from the infrared region of the solar blind band, for example, 905 nm and 1550 nm. On the other hand, the light receiving module 32 receives reflected light (visible light) that is emitted from the lamp unit 20 (projection lens 23) and reflected (scattered) by the inside of the outer lens 71 (visible light transmission region A1) or by fogging attached to the inside and returns, and outputs an electrical signal according to the received reflected light. The light source module 31 and the light receiving module 32 function as a fogging detection sensor that detects fogging attached to the inside of the outer lens 71.

[0039] The light source module 31 includes a semiconductor infrared light source 31a, an oscillation circuit 31b, and a light exit window 31c.

[0040] The semiconductor infrared light source 31a is a semiconductor light emitting element that emits infrared light having a wavelength that belongs to the infrared region of the solar blind band, and is, for example, an LED (light emitting diode) or an LD (laser diode).

[0041] The oscillator circuit 31b is a circuit that receives a control signal from a control device 60 (ECU: Electronic Control Unit) and drives (turns on or off) the semiconductor infrared light source 31a.

[0042] The light exit window 31c is composed of an optical deflection element and a filter (not shown). The optical deflection element is an optical deflection element that controls the infrared light emitted from the semiconductor infrared light source 31a so that the infrared light emitted from the semiconductor infrared light source 31a irradiates the visible light transmission region A1 of the outer lens 71, and is, for example, an optical lens or a diffractive optical element (DOE). The filter is a filter that transmits the infrared light emitted from the semiconductor infrared light source 31a and blocks external light, and is, for example, a low-pass filter.

[0043] The light receiving module 32 includes a light receiving element 32a, a detection circuit 32b, and a light receiving window 32c.

[0044] The light receiving element 32a receives reflected light (visible light) that is emitted from the lighting unit 20 (projection lens 23) and reflected (scattered) back from the inside of the outer lens 71 (visible light transmitting area A1) or from fogging attached to the inside, and outputs an electrical signal corresponding to the received reflected light.

[0045] The detection circuit 32b is a circuit that processes the electrical signal output by the light receiving element 32a and transmits it to the control device 60.

[0046] The light receiving window 32c is configured with a filter (bandpass filter) that transmits reflected light (infrared light) that is emitted from the lighting unit 20 (projection lens 23) and reflected (scattered) by the inside of the outer lens 71 (visible light transmitting area A1) or by fogging attached to the inside and returns, and blocks external light that is not necessary for detection.

[0047] In the antifogging device 30 having the above configuration, the infrared light emitted from the antifogging device 30 (semiconductor infrared light source 31a) is deflected by the optical deflection element (light exit window 31c) and irradiates the visible light transmission region A1 of the outer lens 71. At this time, since infrared light is easily absorbed by water, the infrared light deflected by the optical deflection element (light exit window 31c) and emitted from the antifogging device 30 (semiconductor infrared light source 31a) is absorbed by the fog (water droplets) attached to the inner side of the outer lens 71 (visible light transmission region A1) and heats the fog (water droplets). This causes the fog (water droplets) attached to the inner side of the outer lens 71 (visible light transmission region A1) to evaporate. As a result, the fog (water droplets) attached to the inner side of the outer lens 71 (visible light transmission region A1) can be removed. The wavelength of the infrared light emitted from the antifogging device 30 is preferably in the range of either 895 nm to 915 nm or 1350 nm to 1550 nm. Alternatively, it may be in the range of 915 nm to 960 nm, which is at the foot of the absorption band but has a high optical output of the infrared semiconductor light emitting element (infrared laser).

[0048] The anti-fogging device 30 (housing 33) configured as described above is attached to the bracket 25. By attaching the anti-fogging device 30 (housing 33) to the bracket 25 which is tilted up, down, left and right by the optical axis adjustment mechanism 26 in this manner, the optical axis of the lamp unit 20 can be adjusted by the optical axis adjustment mechanism 26, and the optical axis of the infrared light emitted from the anti-fogging device 30 can also be adjusted.

[0049] Next, the control device 60 (control ECU) will be described.

[0050] As shown in FIG. 1, a control device 60 (control ECU: Electronic Control Unit) includes a processor (not shown), a storage unit 61, and a memory 62, for example.

[0051] The processor is, for example, a CPU (Central Processing Unit). There may be one processor or multiple processors. The processor functions as a fog detector 63 and an anti-fogging device controller 64 by executing a predetermined program (not shown) loaded from a storage unit 61 (for example, a ROM) to a memory 62 (for example, a RAM). Some or all of these may be realized by hardware.

[0052] The fog detection unit 63 executes a fog detection process. The fog detection process is a process for detecting fog attached to the inside of the outer lens 71 (visible light transmission region A1) based on the output of the light receiving module 32 (light receiving element 32a). For example, the fog detection process is a process for comparing the output of the light receiving module 32 (light receiving element 32a) with a threshold value (for example, stored in the storage unit 61) and determining whether the output of the light receiving module 32 (light receiving element 32a) exceeds the threshold value. When the output of the light receiving module 32 (light receiving element 32a) exceeds the threshold value, the fog detection unit 63 detects fog attached to the inside of the outer lens 71 (visible light transmission region A1). On the other hand, when the output of the light receiving module 32 (light receiving element 32a) does not exceed the threshold value, the fog detection unit 63 does not detect fog attached to the inside of the outer lens 71 (visible light transmission region A1).

[0053] When fog adhering to the inside of the outer lens 71 (visible light transmitting region A1) is detected, the antifogging device control unit 64 controls the antifogging device 30 (semiconductor infrared light source 31a) so that the antifogging device 30 (semiconductor infrared light source 31a) emits infrared light. On the other hand, when fog adhering to the inside of the outer lens 71 (visible light transmitting region A1) is not detected, the antifogging device control unit 64 controls the antifogging device 30 (semiconductor infrared light source 31a) so that the antifogging device 30 (semiconductor infrared light source 31a) stops emitting infrared light.

[0054] Next, an example of the operation of the vehicle lighting system 1 having the above configuration will be described.

[0055] FIG. 6 is a flowchart of an operation example of the vehicle lighting system 1.

[0056] First, it is determined whether or not an instruction (for example, an instruction from a user) has been given to turn on or off the vehicle headlamp 10 (step S10). This is realized, for example, by the control device 60 executing a predetermined program.

[0057] Next, if the determination result in step S10 is "ON" (step S10: ON), the vehicle headlamp 10 (semiconductor light-emitting element 21) is turned on (step S11). This is realized, for example, by the control device 60 executing a predetermined program.

[0058] Next, a fogging detection process is executed (step S12). This is realized by the fogging detection unit 63. The fogging detection unit 63 compares the output of the light receiving module 32 (light receiving element 32a) with a threshold value (for example, stored in the storage unit 61), and detects fogging on the inside of the outer lens 71 (visible light transmission area A1) if the output of the light receiving module 32 (light receiving element 32a) exceeds the threshold value. On the other hand, if the output of the light receiving module 32 (light receiving element 32a) does not exceed the threshold value, the fogging detection unit 63 does not detect fogging on the inside of the outer lens 71 (visible light transmission area A1).

[0059] Next, if fogging is detected as a result of step S12 (step S13: YES), the antifogging device 30 (semiconductor infrared light source 31a) emits infrared light (step S14). This is achieved by the antifogging device control unit 64 controlling the antifogging device 30 (semiconductor infrared light source 31a). The infrared light emitted from the antifogging device 30 (semiconductor infrared light source 31a) is deflected by the optical deflection element (light exit window 31c) and irradiates the visible light transmission region A1 of the outer lens 71. The angle θ1 in FIG. 3 and FIG. 5(b) represents the range of infrared light emitted from the antifogging device 30 (semiconductor infrared light source 31a) that irradiates the visible light transmission region A1 (see FIG. 3) of the outer lens 71. At this time, since infrared light is easily absorbed by water, the infrared light emitted from the anti-fogging device 30 is absorbed by the fog (water droplets) attached to the inside of the outer lens 71 (visible light transmission region A1) and heats the fog (water droplets). This causes the fog (water droplets) attached to the inside of the outer lens 71 (visible light transmission region A1) to evaporate. As a result, the fog (water droplets) attached to the inside of the outer lens 71 (visible light transmission region A1) can be removed.

[0060] On the other hand, if no fogging is detected as a result of step S12 (step S13: NO), the defroster 30 (semiconductor infrared light source 31a) stops emitting infrared light (step S15). This is achieved by the defroster control unit 64 controlling the defroster 30 (semiconductor infrared light source 31a).

[0061] Thereafter, the above steps are repeatedly executed until fogging is no longer detected in step S13.

[0062] On the other hand, if the determination result in step S10 is "off" (step S10: off), the vehicle headlamp 10 (semiconductor light-emitting element 21) is turned off (step S16). This is realized, for example, by the control device 60 executing a predetermined program.

[0063] Next, the defrosting device 30 (semiconductor infrared light source 31a) stops emitting infrared light (step S17). This is achieved by the defrosting device control unit 64 controlling the defrosting device 30 (semiconductor infrared light source 31a). This ends the process of FIG. 6.

[0064] As described above, according to this embodiment, the fogging on the outer lens 71 can be removed without using a heater.

[0065] This is because the anti-fogging device 30 that emits infrared light that irradiates the visible light transmitting region A1 of the outer lens 71 is provided.

[0066] Next, a modified example will be described.

[0067] In the above embodiment, an example in which a projector-type lamp unit is used as the lamp unit 20 has been described, but the present invention is not limited thereto. That is, any configuration of lamp unit may be used as long as the lamp unit emits light (visible light) for forming a headlamp light distribution pattern (e.g., a low beam light distribution pattern, a high beam light distribution pattern, or a light distribution pattern for an adaptive driving beam system (ADB)) through the outer lens 71 (visible light transmission region A1). For example, as the lamp unit 20, a reflector-type lamp unit other than a projector-type lamp unit may be used, a direct projection-type lamp unit may be used, a lamp unit using a light guide (e.g., a light guide rod, a light guide plate), or a lamp unit other than these may be used.

[0068] The numerical values ​​shown in the above embodiments are all examples, and it goes without saying that suitable numerical values ​​different from these can be used.

[0069] The above-described embodiments are merely examples in all respects. The present invention should not be construed as being limited by the description of the above-described embodiments. The present invention can be implemented in various other forms without departing from the spirit or main characteristics thereof. [Explanation of symbols]

[0070] 1. Vehicle lighting system 10...Vehicle headlamp 20…Lamp unit 21...Semiconductor light emitting device 22…Reflective surface 23...Projection lens 24…Reflective surface 25…Bracket 26…Optical axis adjustment mechanism 27…Extension 30…Anti-fogging device 31...Light source module 31a...Semiconductor infrared light source 31b…Oscillation circuit 31c…Idemitsu window 32...Light receiving module 32a...Light receiving element 32b…Detection circuit 32c…Light receiving window 33…Housing 60...Control device 61...Storage section 62…Memory 63…Fog detector 64...Anti-fogging device control section 70…Housing 71…Outer lens A1…Visible light transmission area AX 23 …optical axis CL: Cutoff line F1 22 …first focus F2 22 …Second focus F 23 …focus P Lo …Low beam light distribution pattern S1…Light room V…Vehicle

Claims

1. Housing and an outer lens attached to the housing to form a lamp chamber between the housing and an outer lens; A lamp unit is disposed in the lamp chamber and emits visible light that passes through a visible light transmitting region of the outer lens; An anti-fogging device that is disposed in the lamp chamber and emits infrared light that irradiates the visible light transmitting region of the outer lens; A vehicle headlamp comprising:

2. The defrosting device includes a semiconductor light-emitting element that emits infrared light having a wavelength that belongs to the infrared region of the solar blind band, and a light deflector element; 2. The vehicle headlamp according to claim 1, wherein the optical deflection element is configured to deflect infrared light emitted from the semiconductor light-emitting element and enter the optical deflection element, and the deflected infrared light irradiates the visible light transmitting region of the outer lens.

3. A fog detection unit that executes a fog detection process to detect fog attached to the outer lens is further provided.

2. The vehicle headlamp according to claim 1, wherein the anti-fogging device emits infrared light to irradiate the visible light transmitting region of the outer lens when the anti-fogging device detects fogging, and does not emit infrared light when the anti-fogging device does not detect fogging.

4. 2. The vehicle headlamp according to claim 1, wherein the wavelength of the infrared light is selected from the group consisting of 895 nm to 960 nm and 1350 nm to 1560 nm.

5. A bracket to which the lamp unit is attached; and an optical axis adjustment mechanism for adjusting an optical axis of the lamp unit by tilting the bracket. The vehicle headlamp according to claim 1 , wherein the defroster is attached to the bracket.

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