JP7846994B2 - monitoring device - Google Patents

Description

This invention relates to a monitoring device suitable for installation in vehicles such as automobiles, and more particularly to a monitoring device comprising a radar unit.

Advanced Driver Assistance Systems (ADAS) in automobiles require detection and monitoring devices to detect obstacles and other vehicles in front of and around the vehicle. These monitoring devices utilize radar, such as LIDAR (Light Detection and Range) and millimeter-wave radar.

Figure 1 is a plan view illustrating the outline of a vehicle equipped with a monitoring device using millimeter-wave radar. A forward-facing millimeter-wave radar is installed in the front of the vehicle body, for example, inside the emblem E (the millimeter-wave radar is not shown in Figure 1 below). This forward-facing millimeter-wave radar has a narrow field of view (FOV) of approximately ±10 to 15 degrees in the left-right direction relative to the center of the radar (hereinafter referred to as the narrow angle or narrow angle range), and detects objects in the forward area FA of the vehicle.

Furthermore, millimeter-wave radars for surrounding area monitoring are installed on the front and rear of the vehicle body. For example, millimeter-wave radars for front-side monitoring are installed inside the left and right fenders at the front of the vehicle body, and millimeter-wave radars for rear-side monitoring are installed inside the rear bumper at the rear of the vehicle body. The millimeter-wave radars for front-side monitoring have a wide field of view (FOV) of approximately ±60 to 80 degrees in the left-right direction relative to the radar center (hereinafter referred to as wide angle or wide angle range), and detect objects located in the right front-side area (RFSA) and left front-side area (LFSA) of the vehicle. Similarly, the millimeter-wave radars for rear-side monitoring detect objects located in the right rear-side area (RRSA) and left rear-side area (LRSA) of the vehicle.

These millimeter-wave radars are typically installed inside the vehicle body, but the applicant has previously proposed a technology that integrates millimeter-wave radar with vehicle lighting fixtures. Patent Document 1 proposes a technology in which a millimeter-wave radar is installed as a monitoring device inside the headlamp of an automobile. Furthermore, Patent Document 2 describes the installation of monitoring sensors, including millimeter-wave radar, not only inside the headlamp but also inside the rear lamp (taillamp) of an automobile. By installing the millimeter-wave radar inside the lamp in this way, the vehicle can be equipped with the millimeter-wave radar simultaneously with the lamp's installation, which is advantageous in terms of simplifying the assembly process and reducing man-hours compared to installing the millimeter-wave radar independently.

Japanese Patent Publication No. 2020-104799 Japanese Patent Publication No. 2019-117197

Thus, in millimeter-wave radar systems installed within vehicle bodies or lamps, the millimeter waves transmitted from the radar are projected outwards towards the vehicle's surroundings, passing through so-called outer covers such as vehicle panels and lamp outer lenses. However, if the outer cover is curved, the direction of emission of the millimeter waves passing through the outer cover may be altered.

In other words, as will be explained in detail later, millimeter waves transmitted from the millimeter-wave radar at a required emission angle relative to the center of the field of view (FOV) are refracted on the inner surface of the outer cover, and then refracted again on the outer surface before being emitted. At this time, because the outer cover is formed with a curved surface, the inclination of the surface at the inner portion where the millimeter waves are refracted (the inclination in the tangential direction relative to the center of the FOV) differs from the inclination of the surface at the outer portion. Therefore, the emission angle of the millimeter waves emitted from the outer surface of the outer cover changes from the emission angle at which they were transmitted from the millimeter-wave radar.

In millimeter-wave radar, the emission angle of the transmitted millimeter waves is crucial for detecting objects. If this emission angle changes as the waves exit the outer cover, the detection accuracy of the object decreases. In particular, millimeter-wave radars used for surrounding area monitoring have a wide field of view (FOV) to detect objects over a wide area. Furthermore, the angle of incidence to the outer cover is large in the wide-angle region extending from the center of the FOV to both sides. Therefore, changes in the emission angle in the wide-angle region become significant, leading to a noticeable decrease in detection accuracy. This problem also applies to monitoring devices equipped with LiDAR using infrared light.

The objective of this invention is to provide a monitoring device that can prevent a decrease in detection accuracy by preventing changes in the emission direction of electromagnetic waves transmitted through the outer cover.

The present invention relates to a monitoring device comprising a radar unit installed inside the vehicle body or lamp that transmits and receives electromagnetic waves to detect an object, and configured to perform detection by electromagnetic waves through a curved outer cover that covers the radar unit, wherein the radar unit is configured to transmit electromagnetic waves in multiple directions within a required angular range, and the outer cover is configured as an inner and outer surface in the region corresponding to the angular range, such that the electromagnetic waves transmitted from the radar unit are refracted at the inner and outer surfaces and, even after passing through the outer cover, remain in the same direction as the angle transmitted from the radar unit .

In a preferred embodiment of the present invention, the outer cover is configured such that the orientation of the inner surface portion into which electromagnetic waves transmitted from the radar unit enter the outer cover and the orientation of the outer surface portion into which electromagnetic waves are emitted from the outer cover are parallel.

For example, the outer surface of the outer cover is formed as a smooth curved surface, and the inner surface of the outer cover has a continuous surface shape consisting of fine surfaces with different inclination angles corresponding to the electromagnetic wave transmission direction. In this case, the inner surface of the outer cover has a surface shape consisting of fine surfaces with different inclination angles corresponding to the electromagnetic wave transmission direction in at least one of the horizontal and vertical directions.

The monitoring device of the present invention has a radar unit housed within the lamp housing of a vehicle 's lamp , and an outer cover made up of the outer lens of the lamp housing. This monitoring device is configured as a front-side monitoring device housed within a vehicle's headlamp, or as a rear-side monitoring device housed within a vehicle's rear lamp. Furthermore, the radar unit in the monitoring device of the present invention is composed of at least one of millimeter-wave radar or LiDAR.

According to the present invention, since the direction of emission of electromagnetic waves is prevented from changing due to refraction at the inner and outer surfaces as the electromagnetic waves pass through the outer cover, a monitoring device is provided that prevents a decrease in detection accuracy caused by changes in the emission angle.

A plan view illustrating the overview of a vehicle's monitoring system. A schematic perspective view of the headlamp according to Embodiment 1. A schematic cross-sectional view of the headlamp of Embodiment 1 along the line III-III in Figure 2. A schematic partially exploded perspective view of the headlamp of Embodiment 1. (a) and (b) are schematic diagrams illustrating the changes in the direction of emission of millimeter waves (electromagnetic waves) in the outer lens. (a) and (b) are schematic diagrams illustrating the design method for the inner surface shape of the outer lens. A schematic diagram illustrating the design method for the outer surface shape of the outer lens in Embodiment 2. A schematic perspective view of the headlamp according to Embodiment 3. A schematic diagram illustrating the design method for the inner surface shape of the outer lens in Embodiment 3. This is a schematic diagram of Embodiment 3, where (a) is a horizontal schematic diagram and (b) is a vertical schematic diagram.

(Embodiment 1)
Next, Embodiment 1 of the present invention will be described with reference to the drawings. Figure 3 is an external view of an automobile CAR in which the monitoring device of the present invention is applied to headlamps L-HL and R-HL arranged on the left and right front of the vehicle body. The left and right headlamps L-HL and R-HL have a symmetrical configuration, and the figure also shows the external view of the right headlamps R-HL. This right headlamps R-HL is equipped with a container-shaped body 101 that is open on the front or left side, and an outer lens 102 made of light-transmitting resin is fixed to the opening of this body 101 to form a lamp housing 100.

Within this lamp housing 100, a lighting unit 2, which combines a low-beam lamp and a high-beam lamp into a single unit, and a sign unit 3, which serves as both a clearance lamp and a turn signal lamp, are arranged. Furthermore, a radar unit 1, serving as a monitoring sensor, is installed in the left-hand portion of the lamp housing 100 when viewed from the front, i.e., the outer portion in the vehicle width direction. This radar unit 1 is composed of a millimeter-wave radar.

Figure 3 is a schematic cross-sectional view along line III-III in Figure 2, and Figure 4 is a schematic partially exploded perspective view of the right headlamp. The lighting unit 2 consists of three horizontally arranged lighting lamps 21, 22, and 23. Each lamp, though not shown in the illustration, includes a white LED (light-emitting diode) as a light source and a projection lens that projects the white light emitted from the LED in a required light distribution pattern. Here, the two outer lighting lamps 21 and 22 in the vehicle width direction are configured as low-beam lamps that project low-beam light distribution when illuminated. The central lighting lamp 23 in the vehicle width direction is configured as a high-beam lamp that forms a high-beam light distribution when illuminated together with the two low-beam lamps 21 and 2. This lighting unit 2 may also be configured as a so-called ADB (Adaptive Driving Beam) lamp capable of light distribution control.

The sign unit 3 comprises an inner lens 31 extending in the vehicle width direction below the lighting unit 2, and a light source 32 that directs light into the inner lens 31. The inner lens 31 is made of a colorless, translucent material and functions as a light guide, guiding light into its interior. It is formed in a horizontally elongated plate shape with a required vertical width. One plate surface (referred to as the front or outer surface) facing the front of the lamp serves as the light-emitting surface and is opposed to the outer lens 102. The other plate surface (referred to as the rear or inner surface) facing the rear of the lamp has a light-injection portion 33 formed to introduce light emitted from the light source 32 into the interior. Here, the light-injection portions 33 are provided at two different locations on the inner lens 31, each formed as a projection extending from the rear surface of the inner lens 31 by a required dimension.

The light source 32 comprises a white LED 32w that emits white light and an amber LED 32u that emits amber light. The white LED 32w is positioned opposite one side of the light-incident portion 33 of the inner lens 31, and the amber LED 32u is positioned opposite the other side. Therefore, the white light emitted by the white LED 32w enters the inner lens 31 from one side of the light-incident portion 33, and white light is emitted from the light-emitting surface of the inner lens 31. Similarly, the amber light emitted by the amber LED 32u enters the inner lens 31 from the other side of the light-incident portion 33, and amber light is emitted from the light-emitting surface of the inner lens 31. As a result, the sign unit 3 is illuminated as a clearance lamp (CL) or daytime running lamp (DRL) by the illumination of the white LED 32w, and as a turn signal lamp (TSL) by the illumination of the amber LED 32u.

The millimeter-wave radar 1 comprises a radar body 11. The radar body houses an antenna, radio wave modules, and other components within a rectangular container. The side on which the antenna is mounted serves as a millimeter-wave transmitting and receiving surface 11a, which transmits and receives millimeter waves. Millimeter waves transmitted from the millimeter-wave transmitting and receiving surface 11a of the radar body 11 are transmitted through an outer lens 102 and projected externally. These waves are reflected by the object to be detected, and the millimeter waves that have passed through the outer lens are received by the millimeter-wave transmitting and receiving surface 11a, enabling object detection. The radar body 11 is fixedly supported to the lamp body 101 by a bracket 12 and is electrically connected to an ECU (Electronic Control Unit) (not shown) mounted in the vehicle. Object detection is performed in the ECU based on the output of the radar body 11.

In this radar unit 11, the FOV (Field of View) region is defined based on a virtual wave source P when millimeter waves are transmitted in multiple directions. To enable it to function as a front-side monitoring millimeter-wave radar, the central normal direction of the millimeter-wave transmitting/receiving surface 11a is oriented in a predetermined direction. The FOV region, centered on this central normal direction, transmits millimeter waves within an angle range of approximately ±60 to 80 degrees horizontally (left-right) and approximately ±30 to 40 degrees vertically (up-down), enabling object detection. Here, when the millimeter-wave radar 1 is installed within the lamp housing 100, the millimeter-wave transmitting/receiving surface 11a of the radar unit 11 is positioned at an angle of approximately 45 degrees to the right and slightly forward relative to the straight-ahead direction of the vehicle.

In the R-HL headlamp described above, to prevent the radar unit 1, which is disposed within the lamp housing 100, from being exposed to the outside through the outer lens 102, at least the area of the outer lens 102 corresponding to the millimeter-wave radar 1 is configured as a non-transparent area 103 that does not transmit light. Here, the outer lens 102 is formed by so-called two-color molding, and the non-transparent area 103 is molded from black resin. In Figures 2 and 4, the dotted area is the non-transparent area 103 of black resin, and the peripheral edge of the outer lens 102 is also molded from black resin. Instead of black, the vehicle body color may be used. This enhances the design effect of the headlamp. While this non-transparent area 103 cannot be said to function optically as an outer lens, in this invention, this non-transparent area is included and referred to as the outer lens. Furthermore, this outer lens covers the millimeter-wave radar 1 and is configured as the outer cover in this invention.

In this R-HL headlamp, as shown by the solid line in Figure 3, millimeter waves transmitted from the millimeter-wave radar 1, which acts as the radar unit, are transmitted through the outer lens 102 and projected toward the front right area of the vehicle. Furthermore, millimeter waves reflected by an object are transmitted through the outer lens 102 and received by the millimeter-wave radar 1. In this way, the millimeter-wave radar 1 is configured as a monitoring device capable of detecting the position and direction of objects in the front right area of the vehicle by transmitting and receiving millimeter waves transmitted through the outer lens 102.

At this time, as shown in the schematic diagram in Figure 5(a), the millimeter wave L1 transmitted from the millimeter-wave radar 1 at an emission angle θ1 (hereinafter, including the emission angle θ*, the angle is, in principle, the angle relative to the FOV center direction D) is refracted at the inner surface (rear surface) Fi of the outer lens 102, and then refracted again at the outer surface (front surface) Fo, and emitted towards the right front of the vehicle. As shown in a magnified portion in Figure 5(b), the outer lens 102 is formed as a free-form surface to match the curved surface of the vehicle body. Because the inclination angle αi of the tangent t1 of the inner surface part a1 where the millimeter wave L1 is first refracted is different from the inclination angle α2 of the tangent t2 of the outer surface part b1 where it is next refracted, the emission angle θ2 of the millimeter wave L1 emitted from the outer surface part of the outer lens 102 becomes a different angle from the emission angle θ1 and is changed. Therefore, this becomes a factor that reduces the detection accuracy of the millimeter-wave radar 1.

In Embodiment 1, the inner surface shape of the outer lens 102 is designed to prevent changes in the emission angle of millimeter waves caused by the outer lens 102. Figure 6(a) is a schematic diagram illustrating this design method by drawing, as an example of this design method. In Figure 6(a), the outer surface Fo of the outer lens 102, which is the basis for the design, is shown by a solid line, and the provisional inner surface Fi is shown by a dashed line. First, the millimeter wave L11 transmitted from the millimeter-wave radar 1 at an emission angle θ1 is drawn, ignoring the inner surface Fi. An outer surface portion b21 is set where this millimeter wave L11 intersects the outer surface Fo of the outer lens 102, and multiple outer surface portions b22 to b24 (three in this case) are set in the vicinity of this outer surface portion b21. These outer surface portions are preferably set at angular positions obtained by dividing the angle of minimum resolution into multiple parts, considering, for example, the horizontal resolution of the millimeter-wave radar 1. Note that in Figure 6(a), multiple angular positions are shown with larger angular intervals than the actual ones for the sake of clarity.

Next, we draw the emitted millimeter waves L21-L24 emitted from each outer surface portion b21-b24 at an emission angle θ1. These are millimeter waves parallel to millimeter wave L11. Then, we draw the millimeter waves emitted as emitted millimeter waves L21-L24, i.e., the refracted millimeter waves L31-L34 that should become emitted millimeter waves L21-L24 when emitted from the outer surface Fo of the outer lens 102.

The refracted millimeter waves L31 to L34 can be drawn using Snell's law by determining the tangents t11 to t14 of the outer surface Fo of the outer lens 102 at each outer surface portion b21 to b24, and utilizing these tangents t11 to t14. Specifically, as shown in the enlarged illustration of the example at outer surface portion b22, based on the tangent t12 and the normal h12 perpendicular to it, the emission angle of the emitted millimeter wave L22 with respect to the normal h12 is denoted as θo. Using the refractive index n of the outer lens 102 and Snell's law "n sinθi = sinθo", the refraction angle θi of the refracted millimeter wave L32 with respect to the normal h12 at outer surface portion b22 can be determined.

Next, we determine the intersection points c1 to c4 between the refracted millimeter waves L31 to L34 and the millimeter wave L1. Since the refracted millimeter wave L31 at the outer surface b21 does not intersect with the millimeter wave L1, intersection point c1 does not exist. Of the obtained intersection points c2 to c4, we select the intersection point closest to the hypothetical inner surface Fi, in this case, the intersection point c3 with the refracted millimeter wave L33. That is, at this intersection point c3, the millimeter wave L1 is refracted to become the refracted millimeter wave L33, and then further refracted at the outer surface Fo to become the emitted millimeter wave L23.

Therefore, this selected intersection point c3 becomes a part of the inner surface of the outer lens 102. Furthermore, the fine surface portion Fi3 parallel to the tangent t13 at the outer surface portion b23 where the refracted millimeter wave L33 is refracted at the outer surface Fo of the outer lens 102 becomes a part of the inner surface Fi of the outer lens 102 at intersection point c3. This is because the refraction relationship between the millimeter wave L11 and the refracted millimeter wave L33 at intersection point c3 is point-symmetric to the refraction relationship between the refracted millimeter wave L32 and the emitted millimeter wave L22 at the outer surface portion b22 of the outer lens 102. Therefore, the inclination angle of the tangent t13 at outer surface portion b23 becomes equal to the inclination angle of the fine surface portion Fi3 on the inner surface of the outer lens 102 at intersection point c3, and thus they become parallel to each other.

Thus, the millimeter wave L11 is refracted at the fine surface portion Fi3 of the inner surface Fi of the outer lens 102 to become the refracted millimeter wave L33, and this refracted millimeter wave L33 is refracted at the outer surface Fo to become the emitted millimeter wave L23. At this time, by designing the fine surface portion Fi3 of the inner surface Fi as described above, the emitted millimeter wave L23 has the same emission angle θ1 as the millimeter wave L11.

For multiple millimeter waves with different emission angles transmitted from the millimeter-wave radar 1, the refracted millimeter waves are determined at multiple outer surface locations for each wave. Furthermore, the intersection points of these refracted millimeter waves and the original millimeter waves are determined, and the inclination angle of the tangent lines at the outer surface locations corresponding to these intersection points is calculated. Then, at the intersection points, the fine surfaces of the tangent lines with the same inclination angle, i.e., parallel tangents, are determined and designated as part of the inner surface. Based on this, as shown in the schematic diagram in Figure 6(b), by enveloping and continuing each fine surface Fi* at the multiple intersection points indicated by the black dots, while keeping them as close as possible to the provisional inner surface Fi, the inner surface shape of the outer lens 102 can be designed for at least the region corresponding to the FOV region Av.

The above describes a graphical method, but by coordinate and mathematically formulating the outer surface Fo, hypothetical inner surface Fi, millimeter wave L**, outer surface portion b**, outgoing millimeter wave L**, refracted millimeter wave L**, etc., it is possible to design the inner surface of the outer lens 102 using computer calculations.

Furthermore, while intersection point c3 is selected in this embodiment, intersection points c2 or c4 may also be selected, and the inner surface of the outer lens 102 may be formed by minute surface areas obtained from the inclination angles of the tangents t12 and t14 at the corresponding outer surface portions b22 and b24. For example, intersection point c2 of the millimeter wave L22 closest to the optical path of the emitted millimeter wave L21 may be selected, but in this case, the thickness of the outer lens 102 will be reduced, and the lens strength of the outer lens 102 must be considered.

Therefore, with the outer lens 102 designed in this way, as shown in Figure 6(b) for some millimeter waves, within the FOV region, the millimeter waves L** transmitted from the millimeter-wave radar 1 are emitted at the same emission angle as when they were transmitted from the radar unit, even after passing through the outer lens 102. This is also true when the millimeter-wave radar 1 receives millimeter waves through the outer lens 102. This prevents a decrease in detection accuracy caused by changes in the emission angle of the millimeter waves.

The above explanation describes the horizontal inner surface shape of the outer lens 102. The same principles apply to the vertical emission angle of millimeter waves emitted from the millimeter-wave radar 1, and the vertical inner surface shape of the outer lens 102 can be designed using the same design method. By combining these horizontal and vertical inner surface shapes, the three-dimensional inner surface shape of the outer lens 102 can be designed.

In Embodiment 1, the inner surface shape of the outer lens 102 is designed, so the inner surface may not necessarily be formed as a perfectly smooth curved surface. However, since the outer surface of the outer lens 102 is configured as a smooth curved surface, the appearance of the headlamp R-HL is not compromised.

Furthermore, for millimeter waves passing through different parts of the outer lens 102, the path length of each millimeter wave (the optical path length when the millimeter wave passes through) will be different, and an angular error may occur in the angle (phase angle) of each millimeter wave when it passes through the outer lens 102. However, since this angular error can be calculated when designing the plate thickness of the outer lens 102, it can be eliminated by correcting the angular error in the calculation unit that performs calculations when detecting using the phase of millimeter waves in the millimeter-wave radar 1.

Furthermore, the left headlamp L-HL shown in Figure 2 is configured in the same way as the right headlamp R-HL described above. In this case, the configuration and arrangement of the lighting unit 2, the sign unit 3, and the radar unit 1 are symmetrical to those of the right headlamp R-HL. The radar unit 1 will then detect the left front side area LFSA of the vehicle as shown in Figure 1.

(Embodiment 2)
Embodiment 1 designs the inner surface shape of the outer lens 102, but the outer surface shape of the outer lens 102 may also be designed. For example, as shown in Figure 7, a millimeter wave L11 transmitted from the transmission source P (millimeter wave radar 1) at a required emission angle and a refracted millimeter wave L31 refracted by the inner surface portion a11 of the inner surface Fi of the outer lens 102 are drawn. Then, an outer surface portion b31 is set where this refracted millimeter wave L31 and the temporary outer surface Fo of the outer lens 102 intersect, and the inclination angle of the tangent t21 of the surface of this outer surface portion b32 is designed to be parallel to the inclination angle of the tangent t31 of the inner surface portion a11 where the refracted millimeter wave L31 is refracted by the inner surface of the outer lens 102. As a result, the refracted millimeter wave L31, which is refracted by the inner surface portion a11 of the outer lens 102, is emitted from the outer lens 102 at the outer surface portion b31 with the same emission angle as the main millimeter wave L11. The same applies to millimeter waves with different emission angles, such as the millimeter wave L12, so their optical paths and reference numerals are shown in Figure 7 and their explanation is omitted.

According to Embodiment 2, within the FOV region, the millimeter waves transmitted from the millimeter-wave radar 1 are emitted at the same emission angle as when they were transmitted from the millimeter-wave radar 1, even after passing through the outer lens 102. This prevents a decrease in detection accuracy caused by changes in the emission angle of the millimeter waves. In Embodiment 2, the smoothness of the curved surface of the outer lens 102 may be impaired; therefore, it is preferable to apply this embodiment when appearance is not a concern.

(Embodiment 3)
This is an embodiment of the present invention in which a LiDAR is used as the radar unit in the monitoring device. Figure 8 is a schematic perspective view of a car headlamp with a LiDAR installed inside. The same reference numerals are used for parts equivalent to those in Embodiment 1. The LiDAR 1A, which is installed inside the lamp housing 100, has a substantially cylindrical casing 200, and is configured to emit infrared light from the circumferential surface of this casing 200, which is transmitted through the outer lens 102 and emitted toward the front side of the car. The detection of an object using the emitted infrared light is the same as that of a millimeter-wave radar.

As shown in the conceptual configuration of Figure 9, the LiDAR comprises a light source unit 13 housed within a cylindrical casing 200. This light source unit 13 uses an infrared LD (laser diode) 13i, which emits infrared laser light, as its light source. A projection optical system 14, including a cylindrical projection lens, is positioned in front of the light source unit 13 to focus and diverge the laser light from the infrared LD 13i in the vertical direction. The light source unit 13 and the optical system 14 are rotated horizontally within a required angular range by a rotation mechanism 15, which includes a motor. A half-mirror 16 is positioned between the infrared LD 13i and the optical system 14, reflecting the infrared light that has been reflected by the object and received through the optical system 14, and then detected by a light receiving sensor 17.

In this LiDAR 1A, the infrared laser light from the light source unit 13 is diverged vertically by the projection optical system 14 to an angle corresponding to the field of view (FOV), and projected horizontally as a beam of light with a required fine width. When the light source unit 13 and projection optical system 14 are rotated horizontally by the rotation mechanism 15, the infrared laser light is deflected and scanned horizontally in the region corresponding to the FOV. At this time, as shown in the horizontal schematic diagram of Figure 10(a), the light source position Ph of the horizontally scanned infrared laser light is at the center of the casing 200. Also, as shown in the vertical schematic diagram of Figure 10(b), the virtual light source position Pv in the vertical direction of the infrared laser light is at a position on the cylindrical surface of the casing 200.

In this monitoring device, the infrared laser light emitted from the LiDAR 1A is emitted from the outer lens 102 at different emission angles in the horizontal and vertical directions. Therefore, the inner surface shape of the outer lens 102 is designed using the same method as in Embodiment 1. In this design, by assuming that the infrared laser light is emitted from the center of the LiDAR 1A casing 200, the surface shape of the outer lens 102 along the horizontal direction can be designed. Furthermore, by assuming that the infrared laser light is emitted from the cylindrical surface of the LiDAR 1A casing 200, the surface shape of the outer lens 102 along the vertical direction can be designed. By combining these horizontal and vertical surface shapes, the three-dimensional surface shape of the outer lens 102 can be designed.

According to Embodiment 3, in the surface region 104 of the outer lens 102 corresponding to the FOV region Av shown in Figure 8, the infrared laser light transmitted from the LiDAR 1A is emitted at the same emission angle as when it was emitted from the LiDAR 1A, even after passing through the outer lens 102. This prevents a decrease in detection accuracy caused by changes in the emission angle of the infrared laser light. In Embodiment 3, as in Embodiment 2, the surface shape of the outer lens 102 may be designed to prevent changes in the emission angle of the infrared laser light.

In the embodiments described above, an example was shown in which the monitoring device of the present invention was applied to the headlamp of an automobile as a front-side monitoring device. However, it may also be applied to the rear lamp of an automobile as a rear-side monitoring device. That is, the rear lamp can be configured as a monitoring device that monitors the left and right rear-side regions RRSA and LRSA shown in Figure 1.

In this embodiment, the monitoring device of the present invention is integrated into the lamp of a vehicle, but it may also be integrated into the vehicle body. In this case, since millimeter waves and infrared light are refracted by the vehicle body panel covering the front of the radar unit, and the emission angle is changed, the surface shape of the vehicle body panel may be designed as the outer lens of the embodiment, i.e., as the outer cover of the present invention.

In the embodiments, examples of millimeter-wave radar and LiDAR were shown as radar units for the monitoring device. However, the present invention can be applied to any monitoring device that uses a radar unit that detects objects using electromagnetic waves, including light and microwaves.

1. Millimeter-wave radar (radar unit)
1A LiDAR (Radar Unit)
2. Lighting unit 3. Marking unit 11. Radar body 11a. Millimeter wave transmitting/receiving surface 13. Light source unit 14. Projection optical system 15. Rotating mechanism 16. Half mirror 17. Light receiving sensor 100. Lamp housing 101. Body 102. Outer lens (outer cover)
200 Cylindrical Casing CAR Automobile (Vehicle)
R-HL, L-HL Headlamp Av FOV region Fi Inner surface of outer lens Fo Outer surface of outer lens L** Millimeter wave (exit millimeter wave, refracted millimeter wave)
Fi* Fine surface area

Claims (7)

A monitoring device comprising a radar unit installed inside the vehicle body or lamp that transmits and receives electromagnetic waves to detect an object, wherein detection by electromagnetic waves is performed by passing the electromagnetic waves through a curved outer cover that covers the radar unit, wherein the radar unit transmits electromagnetic waves in multiple directions within a required angular range, and the outer cover is configured as an inner and outer surface in the region corresponding to the angular range, such that the electromagnetic waves transmitted from the radar unit are refracted by the inner and outer surfaces and, even after passing through the outer cover, remain in the same direction as the angle transmitted from the radar unit . The monitoring device according to claim 1, wherein the outer cover has an inner surface portion into which electromagnetic waves transmitted from the radar unit are incident, and an outer surface portion into which the electromagnetic waves are emitted from the outer cover, with each surface direction being parallel. The monitoring device according to claim 2, wherein the outer surface of the outer cover is formed as a smooth curved surface, and the inner surface of the outer cover has a surface shape in which fine surfaces with different inclination angles corresponding to the transmission direction of the electromagnetic waves are continuously arranged. The monitoring device according to claim 3, wherein the inner surface of the outer cover has a surface shape in which fine surfaces with different inclination angles corresponding to the transmission direction of the electromagnetic waves are continuously arranged in at least one of the horizontal and vertical directions. The monitoring device according to any one of claims 1 to 4, wherein the radar unit is housed within the lamp housing of the vehicle's lamp, and the outer cover is the outer lens of the lamp housing. The monitoring device according to claim 5, wherein the monitoring device is configured as a front-side monitoring device integrated into the vehicle's headlamp, or as a rear-side monitoring device integrated into the vehicle's taillamp. The monitoring device according to any one of claims 1 to 6, wherein the radar unit comprises at least one of millimeter-wave radar or LiDAR.