Lamp unit

Abstract

To provide a lamp device capable of suppressing attenuation and reflection of radar waves, and sufficiently reducing a functional loss of the radar without changing an electromagnetic wave radiation pattern even when a radar device is placed at a position where the reflector of the lamp and the radar wave overlap.SOLUTION: A lamp device includes a lamp unit 2 comprising, a light emitting element 3, and a reflector having a mirror portion 5M that reflects light from the light emitting element forward, and a radar unit 30 arranged behind the lamp unit 2, the radar unit 30 is arranged such that at least a part of the mirror portion 5M is within a radiation range RR of the electromagnetic waves RW radiated from the radar unit 30. The mirror portion 5M includes a resin body, and a light reflecting surface 5A formed on a surface of the resin body and made of an island-shaped metal layer having metallic luster.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a lamp device, and more particularly to a lamp device for a vehicle incorporating a radar device. [Background technology]

[0002] For driver assistance and autonomous driving, various sensors are used, including acceleration sensors, GPS sensors, cameras, LiDAR (Light Detection and Ranging), millimeter wave sensors, etc.

[0003] In particular, millimeter-wave radar devices maintain high environmental resistance, unaffected by nighttime and backlit environments, and bad weather such as dense fog, rain, and snow. They can also directly detect the distance and direction to an object, as well as its relative speed. Therefore, they are characterized by their ability to detect objects at close range with high speed and precision.

[0004] For example, Patent Document 1 proposes a vehicle lamp in which a millimeter-wave radar is mounted in a lamp chamber and a light-guiding member that transmits millimeter waves is provided between the front cover and the millimeter-wave radar.

[0005] Furthermore, Patent Document 2 discloses a lamp device in which a light guide that does not impair the function of the radar is provided on the front surface of the radar device.

[0006] Patent Document 3 discloses a lamp device that covers at least a portion of the front surface of a radar unit and has a shielding member made of foamed resin. Patent Document 4 discloses a vehicle system that includes a main body component made of micro-cell foam and a radar device that is disposed behind the main body component and configured to transmit / receive radar waves through the interior of the main body component.

[0007] Patent Document 5 discloses a metallic coating film that is an aggregate of fine islands and has metallic luster and is capable of transmitting electromagnetic waves. Patent Document 6 discloses an electromagnetic wave-transmitting metallic luster member that includes an indium oxide-containing layer that is continuously provided on the surface of a substrate, and a metal layer that includes a plurality of portions that are at least partially discontinuous from each other and that is laminated on the indium oxide-containing layer. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Patent No. 4842161 [Patent Document 2] International Publication WO2021 / 125047A1 [Patent Document 3] International Publication WO2021 / 125044A1 [Patent Document 4] Special Publication No. 2021-509467 [Patent Document 5] Patent No. 5465030 [Patent Document 6] Patent No. 6400062 Summary of the Invention [Problem to be solved by the invention]

[0009] However, when a light guide is provided on the front surface of a radar device, there are both optical and electromagnetic constraints, such as the brightness of the light guide decreasing if the light guide is made thin due to the transmission of electromagnetic waves, and the transmittance of the electromagnetic waves decreasing if the light guide is made thick.

[0010] In particular, in the past, it was assumed that the light guide or shielding member would be provided in front of the radar device and placed near the daytime running lamps or signal lights, and it was not assumed that the radar device would be placed in a position that would interfere with the headlights, which are the main driving lamps.

[0011] The present invention has been made in consideration of the above points, and aims to provide a lamp device that can suppress the attenuation and reflection of radar waves even when the radar device is placed in a position where the lamp reflector and the radiated electromagnetic waves (radar waves) overlap, without changing the electromagnetic wave radiation pattern, and in which the functional loss of the radar is sufficiently reduced. [Means for solving the problem]

[0012] A lamp device according to one embodiment of the present invention comprises: a lamp unit including a light source and a reflector having a mirror portion that reflects light from the light source forward; a radar unit disposed behind the lamp unit, the radar unit is disposed so that at least a part of the mirror portion is within a radiation range of the electromagnetic waves emitted by the radar unit; The mirror portion has a resin body and a light-reflecting surface formed on the surface of the resin body and made of an island-shaped metal layer having metallic luster. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a perspective view showing a main part of a lamp device 1 according to a first embodiment of the present invention. [Figure 2] FIG. 2 is an exploded perspective view of the main part of the lamp device 1. [Figure 3] FIG. 2 is a front view of the main part of the lamp device 1. [Figure 4] FIG. 4 is a cross-sectional view showing a cross section taken along line AA shown in FIG. [Figure 5] 3 is a partially enlarged cross-sectional view showing a cross section of a part W of a mirror portion 5M of a reflector 5 in an enlarged manner. FIG. [Figure 6] 10 is a partially enlarged cross-sectional view showing a cross section of a part W of another example of the mirror portion 5M. FIG. [Figure 7] 10 is a partially enlarged cross-sectional view showing a cross section of a part W of still another example of the mirror portion 5M. FIG. [Figure 8A]2 is a top view schematically showing the relative positional relationship between a reflector 5 and a radar unit 30 when the lamp device 1 is viewed from above. FIG. [Figure 8B] 10 is a diagram showing another example of the relative positions of the reflector 5 and the radar unit 30. FIG.

[0014] Fig. 1 is a perspective view showing the main parts of a lamp device 1 according to a first embodiment of the present invention, Fig. 2 is an exploded perspective view of the main parts of the lamp device 1, and Fig. 3 is a front view of the main parts of the lamp device 1. Also, Fig. 4 is a cross-sectional view showing a cross section taken along line AA shown in Fig. 3.

[0015] The figure shows a three-axis coordinate system in which the traveling direction of the vehicle on which the lamp device 1 is mounted is the y direction, the left direction is the x direction, and the downward direction (gravity direction) is the z direction.

[0016] The lamp device 1 according to this embodiment is a vehicle lighting fixture and is used as headlamps disposed on the left and right sides of the front of the vehicle. Because the left and right headlamps have the same basic configuration, only one of the lamp devices 1 (left headlamp) disposed on the front left of the vehicle will be illustrated and described below.

[0017] Although the lamp device 1 will be described as a headlamp for main driving, it may also be a lamp device having the purpose and function of emitting light to the outside, such as a tail lamp or backlight.

[0018] In this specification, a vehicle is described as an automobile, but the present invention is not limited to this. That is, in this specification, a vehicle refers to a vehicle such as a ship or an aircraft, and manned or unmanned transportation or moving means.

[0019] 1 to 3, the lamp device 1 according to this embodiment includes three reflective lamp units 2 arranged side by side in the horizontal direction. Also, as shown in Fig. 4, each lamp unit 2 includes a light source including a light-emitting element 3 that is an LED and a rectangular flat circuit board 4 on the underside of which the light-emitting element 3 is mounted, and a reflector 5 that reflects light emitted downward from the light-emitting element 3 toward the front of the vehicle.

[0020] Although not shown, the three lamp units 2 are housed in a lamp chamber defined by a housing and an outer lens, which is a transparent cover that covers the front opening of the housing.

[0021] The lamp device 1 also has a radar unit 30, which is a radar device, as an obstacle detection device. As shown in FIGS. 1 to 3, the radar unit 30 is disposed behind the reflector 5 of the lamp unit 2 (in the -y direction).

[0022] The radar unit 30 is controlled by, for example, an ECU (Electronic Control Unit) (not shown). The radar unit 30 emits electromagnetic waves (millimeter waves) from a transmitting antenna and receives the waves reflected by an object using a receiving antenna.

[0023] The received signal is processed by the control device to detect the distance, angle, and speed to the object, thereby performing obstacle detection. The radar unit 30 is used, for example, as an obstacle detection device for an Advanced Emergency Braking System (AEBS) and an Adaptive Cruise Control (ACC). Alternatively, the radar unit 30 can be used as a rear / side obstacle detection device and a pedestrian detection device.

[0024] In terms of resolution and accuracy, millimeter waves in the 76-81 GHz band, particularly millimeter waves in the 76-77 GHz band or 79 GHz band, are preferably used as the radiated electromagnetic waves in the radar unit 30. However, the frequency band is not limited to the above, and other frequency bands, such as quasi-millimeter waves in the 24 GHz band, may also be used.

[0025] In each lamp unit 2, the circuit board 4 is positioned and fixed to the upper surface of the reflector 5. That is, as shown in Figures 1 and 2, positioning pins 6 are integrally provided in upright positions on the upper surface of the reflector 5, and circular positioning holes 7 (see Figure 2) are formed in three positions on the circuit board 4 (three positions corresponding to the positioning pins 6 of the reflector 5).

[0026] Therefore, by fitting the three positioning pins 6 erected on the upper surface of the reflector 5 into the three positioning holes 7 formed in the circuit board 4 and placing the circuit board 4 on the upper surface of the reflector 5, the circuit board 4 can be accurately positioned on the upper surface of the reflector 5.

[0027] Then, when the circuit board 4 is adhered to the upper surface of the reflector 5 in this state using an adhesive or the like with high thermal conductivity, the circuit board 4 is fixed in position on the upper surface of the reflector 5. The lower surface of the circuit board 4 has a low reflectance, and in this embodiment, a black resist film is formed on the lower surface of the circuit board 4.

[0028] 4, the light-emitting element 3 is mounted on the bottom surface of the circuit board 4 so that its light emission direction faces downward (z direction). The circuit board 4 and the reflector 5 may be fixed together by screws or thermal caulking, in addition to being bonded with an adhesive. In this embodiment, a black resist film with a reflectance of 10% or less is formed on the bottom surface of the circuit board 4.

[0029] Here, in addition to the resist film, a black coating film with a reflectance of 10% or less may be formed on the bottom surface of circuit board 4, and the thickness of the coating film and the concentration of the reflective material (for example, carbon powder) may be appropriately adjusted to form a coating on the bottom surface of circuit board 4 with a reflectance of 10% or less. Furthermore, because carbon powder also has light absorption properties, a black resist film with a highly absorbing surface with a light absorption rate of 90% or more may be formed on the bottom surface of circuit board 4. In other words, the coating film that suppresses glare may have not only low reflectance but also high absorption.

[0030] Each reflector 5 is integrally molded from resin and has a reflective surface 5A that is curved like a paraboloid of revolution. As shown in Fig. 4, an opening 5B is formed in a part of the upper wall of each reflector 5, through which light L0 emitted downward from the light-emitting element (LED) 3 passes.

[0031] Each reflector 5 is rotatably supported on the upper surface of a bracket 8 that is integrally molded from resin into a rectangular frame shape. That is, as shown in Fig. 2, a cylindrical bearing 5D is integrally provided in the center of the upper wall of each reflector 5 so as to protrude, and this bearing 5D is fitted from above onto the outer periphery of a cylindrical boss 8A that is integrally provided upright on the upper surface of the bracket 8, so that each reflector 5 is supported on the upper surface of the bracket 8 so as to be horizontally rotatable about the boss 8A.

[0032] Next, the reflector 5 and the radar unit 30 will be described in detail with reference to Figures 4 and 5. Figure 4 shows a cross section of the lamp device 1 in a plane (yz plane) perpendicular to the left-right directions (±x directions).

[0033] 4, the reflector 5 includes a base 5C and a mirror portion 5M erected downward (in the z direction) from the base 5C. The base 5C has a substantially flat plate shape and is formed so as to be substantially parallel to the horizontal plane (xy plane) when the lamp device 1 is attached to a vehicle. The mirror portion 5M has a curved reflective surface 5A.

[0034] In the lamp device 1, the circuit board 4 is placed on a base 5C. When current is supplied to each lamp unit 2 from a power source (not shown), such as a battery, the light-emitting element 3 emits light, and the light L0 passes through the opening 5B of the reflector 5 and is emitted toward the reflecting surface 5A of the reflector 5. Then, the light L1 reflected by the reflecting surface 5A of the reflector 5 passes through a transparent outer lens (not shown) and is irradiated toward the front of the vehicle, and the lamp device 1 functions as a headlamp.

[0035] A radar unit 30 having an electromagnetic wave emitting surface 30S is disposed behind (in the -y direction) the reflector 5 of the lamp unit 2. More specifically, the electromagnetic waves RW radiated from the electromagnetic wave emitting surface 30S of the radar unit 30 are incident on the mirror portion 5M of the reflector 5 from the rear surface of the reflector 5, and at least a portion of the waves passes through the mirror portion 5M and is radiated forward.

[0036] The lamp unit 2 and the radar unit 30 are positioned so that the light source consisting of the light-emitting element 3 and the circuit board 4, and the base 5C of the reflector 5, etc., are not within the radiation range RR of the radiated electromagnetic waves RW from the radar unit 30. In other words, the lamp unit 2 and the radar unit 30 are positioned so that only the mirror portion 5M of the reflector 5 is within the radiation range RR of the radiated electromagnetic waves RW.

[0037] The radar radiation range RR is equivalent to the radar detection range expressed as the radar FOV (Field Of View). The radar radiation range RR is determined as a specific range that requires detection. For example, a radar for detecting the periphery of a vehicle has a detection range of approximately ±20° in the vertical direction and ±80° in the horizontal direction relative to the normal direction of the electromagnetic wave radiation surface 30S of the radar unit 30.

[0038] 5 is a partially enlarged cross-sectional view showing an enlarged cross section of a portion W of the mirror portion 5M of the reflector 5. The mirror portion 5M is made up of a foamed resin body 51, a flat resin layer 52 formed on the foamed resin body 51, and an island-shaped metal layer 53 formed on the flat resin layer 52.

[0039] The foamed resin of the foamed resin body 51 is formed by sealing carbon dioxide gas or the like in a resin such as polycarbonate, acrylic, polyimide, or epoxy, creating bubbles in the resin. Because the gas is sealed in the resin, the dielectric constant is lowered, making it possible to significantly reduce the influence on electromagnetic waves. Therefore, the electromagnetic wave transmission characteristics of the foamed resin body 51 are good. Note that if the expansion ratio of the foamed resin is 2 times or more, the influence of the resin can be almost negligible.

[0040] The surface of the foamed resin body 51 is flattened by the flat resin layer 52. The unevenness of the surface of the foamed resin causes light to scatter, making it difficult to distribute light. It is possible to form the flat resin layer 52 with a flat surface by spraying a highly viscous epoxy resin or the like onto the surface of the foamed resin body 51 in a manner similar to a painting process.

[0041] As another method, the flat resin layer 52 can be formed not only by the painting process but also by forming the foamed resin body 51 using a mold, by raising the temperature of the mold to a high temperature to melt the foamed resin surface at the contact surface between the mold and the foamed resin body, thereby forming a flat surface.

[0042] In addition, by using a laminated film made of resins with different melting points, such as PET+PP (PET: polyethylene terephthalate, PP: polypropylene), and welding the resin with a lower melting point to the foamed resin, it is possible to flatten the surface of the foamed resin body 51.

[0043] Furthermore, because epoxy resin has high viscosity, it does not penetrate deep into the foamed resin. Also, for example, in the case of a PET+PP welded laminated film, it is possible to prevent the resin from penetrating deep into the foamed resin by controlling the thickness of the welded resin layer, which has a low melting point.

[0044] By setting the thickness (TF) of the flat resin layer 52, i.e., the laminate of epoxy resin or resins with different melting points, to 1 / 20 or less of the effective wavelength λd of the radiated electromagnetic wave RW within the resin (TF≦λd / 20), it is possible to create a surface on which an island-shaped metal layer 53 can be formed without deteriorating the electromagnetic wave transmission characteristics of the foamed resin.

[0045] An island-shaped metal layer 53 is formed on the flat resin layer 52. The island-shaped metal layer 53 is an aggregate of minute islands, and is a metal coating that has metallic luster and is capable of transmitting electromagnetic waves.

[0046] Here, the island-shaped metal layer 53 has an island-like structure in which the metal layer is divided by fine cracks. The island-shaped metal layer 53 can reflect the light L0 from the light-emitting element 3 with sufficient reflectance. Therefore, the mirror portion 5M fully functions as a reflector.

[0047] Examples of metals that can be used for the island-shaped metal layer 53 include, but are not limited to, indium, palladium, nickel, nickel alloys, copper, copper alloys, silver, silver alloys, tin, and tin alloys. The island-shaped metal layer 53 can be formed by electroless plating of these metals.

[0048] As shown in FIG. 5, the mirror portion 5M having such a configuration reflects the light L0 from the light-emitting element 3 with sufficient reflectivity, thereby obtaining reflected light L1 and suppressing attenuation of the radiated electromagnetic wave RW from the radar unit 30.

[0049] Therefore, even if the radar unit 30 is disposed behind the reflector 5 and the radiated electromagnetic waves RW are incident on the mirror portion 5M of the reflector 5 from the rear surface of the reflector 5, the obstacle detection function of the radar unit 30 is fully exhibited.

[0050] In other words, even if the radar unit 30 is placed at a position where the mirror portion 5M of the reflector 5 overlaps with the radiated electromagnetic waves (radar waves), it is possible to suppress attenuation and reflection of the radiated electromagnetic waves, without changing the electromagnetic wave radiation pattern, and it is possible to provide a lamp device in which the functional loss of the radar is sufficiently reduced.

[0051] In addition, the degree of freedom in arranging the radar unit 30 is increased, making it possible to apply it to obstacle detection for various purposes. Furthermore, since the radar unit 30 is arranged behind the reflector 5, it is difficult to see from the outside, and the radar unit 30 can be hidden, which is advantageous in terms of design.

[0052] 6 is a partially enlarged cross-sectional view showing a cross section of a part W of another example of the mirror portion 5M. The mirror portion 5M is made up of a foamed resin body 51, a base layer 55 formed on the foamed resin body 51, and an island-shaped metal layer 53 formed on the base layer 55.

[0053] The base layer 55 is made of indium tin oxide (ITO). The base layer 55 can be formed on the foamed resin body 51 by sputtering, vapor deposition, or the like. The base layer 55 is not limited to indium tin oxide (ITO), and metal oxides such as indium oxide and indium zinc oxide (IZO) can also be used.

[0054] Furthermore, by setting the thickness (TU) of the base layer 55 to 1 / 20 or less of the effective wavelength λu of the radiated electromagnetic wave RW within the base layer 55 (TU≦λu / 20), it is possible to create a surface on which an island-shaped metal layer 53 can be formed without deteriorating the electromagnetic wave transmission characteristics of the foamed resin.

[0055] 7 is a partially enlarged cross-sectional view showing a cross section of a part W of still another example of mirror section 5M. Mirror section 5M is made of a flat resin substrate 56, an underlayer 57 formed on resin substrate 56, and an island-shaped metal layer 53 formed on underlayer 57. Underlayer 57 is similar to underlayer 55 described above, and may be made of a metal oxide or the like.

[0056] The resin substrate 56 is made of a non-foaming resin and has a thickness TR. When the effective wavelength of the radiated electromagnetic wave RW within the resin body 56 is λr, if the thickness TR satisfies the following relationship, it is possible to reduce reflection losses occurring at the interface between the resin body 56 and space and at the interface between the resin substrate 56 and the underlayer 57.

[0057] TR=m×λr / 2 (m is a natural number) Even if the thickness TR of the resin base 56 does not necessarily perfectly match the above relational expression, reflection loss can be suppressed extremely effectively by setting it to fall within a frequency band in which the power reflection loss is -10 dB or less (reflected power is 10% or less) for the frequency f of the radiated electromagnetic wave RW.

[0058] Even in the case described with reference to Figures 6 and 7, if the radar unit 30 is placed behind the reflector 5 and the radiated electromagnetic waves RW are incident on the mirror portion 5M of the reflector 5 from the back of the reflector 5, the obstacle detection function of the radar unit 30 is fully exhibited.

[0059] Next, the arrangement angles of the reflector 5 and the radar unit 30 will be described with reference to Fig. 8A and Fig. 8B. Fig. 8A is a diagram schematically showing the relative arrangement relationship between the reflector 5 and the radar unit 30 when the lamp device 1 is viewed from above (xy plane) (also referred to as top view). Fig. 8B is a diagram showing another example of the arrangement relationship between the reflector 5 and the radar unit 30.

[0060] In the case shown in Figure 8A, the radar unit 30 and the reflector 5 are arranged so that the central axis AX of the electromagnetic wave emitting surface 30S of the radar unit 30 (i.e., the radiation central axis of the radiated electromagnetic wave RW) is in the same direction (+y direction) as the irradiation direction of the reflector 5 (i.e., the direction ahead of the vehicle).

[0061] As described above, each reflector 5 is supported rotatably in a horizontal plane. Therefore, regardless of the irradiation direction of the reflector 5, the reflector 5 may be arranged so that the irradiation central axis CX and the radiation central axis AX of the radiated electromagnetic wave RW are in the same direction.

[0062] In the case of another arrangement example shown in FIG. 8B, the radar unit 30 and the reflector 5 are arranged so that the central radiation axis AX of the radiated electromagnetic wave RW forms an angle θ relative to the central irradiation axis CX of the reflector 5.

[0063] Even if the radar unit 30 and the reflector 5 are arranged at a relative angle θ as shown in Figure 8B, the obstacle detection function of the radar unit 30 is fully exhibited, as described with reference to Figures 4 to 7.

[0064] As explained in detail above, even if the radar device is placed in a position where the reflector of the main running lamp and the radiated electromagnetic waves (radar waves) overlap, it is possible to suppress the attenuation and reflection of the radar waves, and it is possible to provide a lamp device in which the electromagnetic wave radiation pattern is not changed and the loss of radar function is sufficiently reduced. [Explanation of symbols]

[0065] 1: Lamp unit 2: Lamp unit 3: Light-emitting element 4: Circuit board 5: Reflector 5C: Reflector base 5M: Mirror section 30: Radar unit 30S: Electromagnetic radiation surface 51: Foam resin body 52: Flat resin layer 53: Island metal layer 55,57: Base layer 56: Resin substrate RR: Electromagnetic radiation range RW: Radiated electromagnetic wave

Claims

1. a lamp unit including a light source and a reflector having a mirror portion that reflects light from the light source forward; a radar unit disposed behind the lamp unit, the radar unit is disposed so that at least a part of the mirror portion is within a radiation range of the electromagnetic waves emitted by the radar unit; the mirror portion has a resin body and a light-reflecting surface formed on a surface of the resin body and made of an island-shaped metal layer having a metallic luster; The resin body has a foamed resin body and a base layer made of a metal oxide formed on the foamed resin body, and the island-shaped metal layer is formed on the base layer.

2. 2. The lamp device according to claim 1, wherein TU≦λu / 20 is satisfied, where TU is a thickness of said underlayer and λu is an effective wavelength of said radiated electromagnetic wave in said underlayer.

3. A lamp unit comprising a light source and a reflector having a mirror portion that reflects light from the light source forward; a radar unit disposed behind the lamp unit, the radar unit is disposed so that at least a part of the mirror portion is within a radiation range of the electromagnetic waves emitted by the radar unit; the mirror portion has a resin body and a light-reflecting surface formed on a surface of the resin body and made of an island-shaped metal layer having a metallic luster; The resin body comprises a resin substrate and a base layer made of a metal oxide and formed on the resin substrate, and the island-shaped metal layer is formed on the base layer.

4. When the thickness of the resin substrate is TR and the effective wavelength of the radiated electromagnetic wave in the underlayer is λr, TR and λr are expressed by the following formula: TR = m × λr / 2 (m is a natural number) The lamp device according to claim 3 , wherein

5. 4. The lamp device according to claim 3, wherein TR is set so that, when the thickness of the resin substrate is TR and the effective wavelength of the radiated electromagnetic wave in the base layer is λr, TR is set so that TR<λr / 2 is satisfied when the reflection loss of the resin substrate for the radiated electromagnetic wave is less than the passage loss, and the reflection loss is −10 dB or less when the reflection loss is equal to or greater than the passage loss.

6. 6. The lamp device according to claim 4, wherein TU≦λu / 20 is satisfied, where TU is a thickness of the underlayer and λu is an effective wavelength of the radiated electromagnetic wave within the underlayer.

7. 7. The lamp device according to claim 1, wherein the radar unit is disposed in a positional relationship such that the light source is not within a radiation range of the radiated electromagnetic waves of the radar unit.

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