JPH07270602A - Lens for receiving light, light receiving device, photoelectric sensor and laser radar using them and vehicle loading laser radar - Google Patents

Abstract

PURPOSE:To realize the angle of visibility as wide as possible and to obtain the almost uniform distribution of received light quantity by condensing light beams made incident from respective light receiving areas beared by plural lens parts and having different incident angles at one place. CONSTITUTION:When the optical axis (reference optical axis) of the central lens part L1 is defined as O1 and the optical axes of the lens parts L2 and L3 on both sides are respectively defined as O2 and O3, the optical axes O2 and O3 of the lens parts L2 and L3 on both sides are deviated from the reference optical axis O1. The lens part; L2 and L3 have the different angle of visibility from that of the lens part L1. Besides, the lens parts L1, L2 and L3 have a common focusing position at one place and the light receiving surface 21 of a photodetector 20 is arranged at the focusing position. Therefore, since different visual field ranges are respectively beared by the lens parts L1, L2 and L3, the whole of the angles of the visibility thereof becomes the angle of the visibility of a lens 10. Thus, the lens parts L1, L2 and L3 have an almost identical light receiving area and the received light quantity can be uniformized within the range of the desired angle of visibility.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention receives light emitted from an object to be detected (including light returned from a light source projected onto the object to be detected and reflected by the object to be detected). The present invention relates to a photoelectric sensor and a laser radar that output a detection signal, a light receiving device and a light receiving lens used therein, and a vehicle equipped with the laser radar.

[0002]

FIG. 22 shows a light receiving area (detection area of an object to be detected) of the most typical conventional reflection type photoelectric sensor 70. Within the range covered by the projected light from the photoelectric sensor, the light receiving area is determined by the range in which the light receiving optical system collects the reflected light from the object to be detected and the sensitivity of the light receiving element that receives the light collected by the light receiving optical system.
In particular, the angular range of the light receiving area is determined by the field of view of the light receiving optical system (one or a plurality of lenses combined).

Various attempts have been made to widen the angular range of the light receiving area of the photoelectric sensor. One of them is to arrange a plurality of photoelectric sensors 70A to 70C in a line as shown in FIG. However, according to this configuration, a plurality of photoelectric sensors are required, which is expensive, and a space for arranging the plurality of photoelectric sensors is required in the detection device, so that the size of the entire detection device is increased. is there.

The other is to dispose the light receiving element away from the focal position of the light receiving optical system (defocusing). FIG. 24 shows a slightly exaggerated view of the widening of the viewing angle due to this defocusing.

FIG. 25 shows a defocused light receiving optical system. The light receiving element is arranged so that the light receiving surface 73 is located in front of the focal position of the light receiving lens 72 included in the light receiving optical system (position closer to the lens). In this example, at the position of the light receiving surface 73, the size of the light beam condensed by the lens 72 is set to be three times as large as that of the light receiving surface (three times defocusing) (one that is orthogonal to the optical axis. Comparison in length in the direction).

The lower part of FIG. 25 shows the relationship between the angle of the visual field and the amount of light incident on the light receiving element (light receiving amount). The viewing angle when no defocusing is performed (when the light receiving surface is located at the focal position of the lens) is indicated by A0. Let A1 be the desired viewing angle. When the desired viewing angle A1 is large, the amount of received light is not uniform within the range of the viewing angle A1 even if the defocus is tripled. That is, the amount of received light gradually decreases in the peripheral area of the visual field.

In order to make the amount of received light uniform within the desired viewing angle A1, it is necessary to further increase the degree of defocus. FIG. 26 shows a light receiving optical system in the case of defocusing by 4 times, and a relationship between a viewing angle and a light receiving amount. Certainly, the amount of received light is substantially uniform within the range of the desired viewing angle A1, but there is a problem that the amount of received light is reduced.

[0008]

DISCLOSURE OF THE INVENTION The present invention provides a light-receiving lens capable of realizing a wide viewing angle as much as possible and a substantially uniform light-receiving amount distribution, and a light-receiving device, a photoelectric sensor and a laser radar using the light-receiving lens. With the goal.

It is another object of the present invention to provide a light-receiving lens capable of varying the amount of light received according to a viewing angle, and a light-receiving device, a photoelectric sensor and a laser radar which use this light-receiving lens. .

The present invention further provides a vehicle equipped with the above laser radar.

The light-receiving lens according to the present invention is composed of a plurality of lens portions, which are combined so that their optical axes are located at different positions, so that different incident angles from the respective light-receiving areas shared by the lens portions can be obtained. It is configured to collect the incident light that it has in one place. Whether the lens part is a convex lens (single-convex lens, biconvex lens),
Or realized by Fresnel lens.

According to this invention, since the optical axes of the plurality of lens portions are displaced from the basic optical axis of the lens, the respective lens portions have different visual field ranges and the visual field is broadened as a whole. By equalizing the areas of the incident surfaces (light receiving surfaces) of the plurality of lens portions, the amount of received light can be made uniform. Further, even if the NA (aperture) of each lens portion is small, it is possible to increase the NA as a whole and the amount of received light is large, and since the NA of each lens portion is small, the lens can be made thin, and the light receiving sensor When applied to, a thin light receiving sensor can be realized.

By integrally forming the light receiving lens, it can be provided at a low cost. Since the lens is thin, the molding time is shortened and the cost can be reduced.

When the lens portion of the light receiving lens is composed of a biconvex lens, it is preferable to form an emission surface on the corresponding lens portion so as to cover the area of the light incident on the incidence surface of each lens portion. As a result, it is possible to eliminate the problem that the light that has entered one lens portion emerges from the exit surface of the other lens portion and becomes stray light.

By changing the area of the lens portion of the light receiving lens, the received light amount distribution can be changed according to the viewing angle. For example, by increasing the area of the incident surface toward the lens portion located in the center and decreasing the area of the incident surface toward the periphery, it is possible to obtain the largest received light amount distribution in the central portion.

The focal lengths of a plurality of lens portions of the light-receiving lens may be equal, or the focal lengths of the lens portions located in the periphery thereof may be longer than the focal lengths of the lens portion located in the center. Good. Particularly, in the latter mode, when the light receiving element is arranged corresponding to the central lens portion, it becomes possible to receive the light condensed to the same degree from all the lens portions.

In another embodiment, a lens capable of achieving astigmatism is provided. That is, the focal lengths of the plurality of lenses in one direction are set to be different from the focal lengths of the lenses in the direction orthogonal thereto.

The above-described light-receiving lens is used in the light-receiving device according to the present invention. In one aspect, the light receiving element is
It is arranged at the focal position of a plurality of lens portions or a lens portion having the shortest focal length. In another embodiment, the light receiving element is arranged at a position closer to the light receiving lens or farther from the light receiving lens from the focal position of the plurality of lens portions or the lens portion having the shortest focal length. Particularly in the latter embodiment, the amount of received light is continuously connected in the boundary area of the lens portion.

A photoelectric sensor according to the present invention comprises the above-mentioned light receiving device and a light projecting device. As the light projecting device, a device equipped with a multi-beam light source or a scanning beam projecting device is preferably used.

A laser radar according to the present invention comprises the above-mentioned light receiving device. According to the present invention, a vehicle equipped with this laser radar is provided.

[0021]

1 and 2, a light-receiving lens 10 is a compound lens composed of three lens portions L1, L2 and L3, and these lens portions L1 to L3 are arranged in a line and integrated. Has been done. These lens portions L1 to L3 are single-convex lenses, and the light emitting side surface (the surface facing the light receiving element) of the light receiving lens 10 is formed flat.

Optical axis (center axis) of the central lens portion L1
The reference optical axis is O1, and the optical axes (center axes) of the lens portions L2 and L3 on both sides are O2 and O3, respectively. The optical axes O2 and O3 of the lens portions L2 and L3 on both sides are at positions displaced from the reference optical axis O1. It is easy to understand if it is considered that a part of the one-sided convex lens indicated by the broken line LP is the lens part L2. The lens portion L3 can be similarly considered. These lens portions L2 and L3 are the lens portion L1.
It has a different viewing angle from. This means that the lens part L
It is also clear from the fact that the two light receiving optical axes (shown by the broken line R2) form an angle (tilt) with respect to the reference optical axis O1.
These lens portions L1, L2 and L3 have a common focal position at one place, and the light receiving surface 21 of the light receiving element 20 is arranged at this focal position.

Therefore, as shown in FIG. 3, the lens portions L1, L2, and L3 share different visual field ranges (visual field angles) AL1, AL2, and AL3, respectively. The entire viewing angles AL1 to AL3 become the viewing angle A1 of the lens 10. The sizes of the lens portions L1 to L3 may be determined so that the viewing angle A1 covers a desired range. Since the lens portions L1, L2 and L3 have substantially the same light receiving area, the light receiving amount can be made uniform within the range of the desired viewing angle A1 (conversely, the lens portion L1 can be made uniform in the light receiving amount). , L2, L3 area etc. can be determined).

Thus, as compared with the conventional defocused light receiving optical system shown in FIGS. 25 and 26, it has a wider viewing angle, a larger light receiving amount, and the light receiving amount is substantially uniform within the range of the viewing angle. A different light receiving optical system can be realized.

Further, when a lens having the same diameter (size) as the light-receiving lens (composite lens) 10 is manufactured by a single lens as in the conventional example, the center thickness of the lens becomes large. Lens 10 for the lens 10 for use
NA (opening) of 1, L2, L3 becomes small, and the thickness can be made thin.

This is particularly effective when the total thickness of the photoelectric sensor 30 is restricted as shown in FIG. In this case, the distance between the light receiving lens and the light receiving element must be shortened. If a conventional single lens is used, the thickness cannot be increased, so that the lens NA is reduced and the light receiving lens area cannot be expanded. If the compound lens 10 for receiving light is used, the thickness of the lens 10 can be reduced, and moreover, the total light receiving area corresponding to 3 times the NA of each lens portion can be secured, and the light receiving amount is increased.

The compound lens 10 as described above can be manufactured by bonding the individual lens parts to each other, but it is preferably integrally molded by injection molding or another method. The integral molding can shorten the manufacturing time and reduce the cost. Being able to reduce the lens thickness also has the advantage that the molding time can be shortened (cooling time shortened).

Although the three lens portions are arranged in a line in one direction in FIG. 2, other arrangements may be used. For example, four or more lens portions can be arranged two-dimensionally with a spread. The number of lens portions forming the light-receiving compound lens can be any number as long as it is two or more.

FIG. 4 shows an embodiment in which the light-receiving compound lens 10 is realized by a refractive Fresnel lens. Three refracting Fresnel lens parts L1, L2, L3 are arranged in a line and integrated. The optical axes (center axes) O2 and O3 of the Fresnel lens portions L2 and L3 on both sides are displaced from the optical axis (center axis) O1 of the central Fresnel lens portion L1 to both sides. Even when such a Fresnel lens is used, the viewing angle can be widened, the amount of received light can be increased, and the received light amount distribution can be made uniform as described above. In particular, Figure 4
According to this configuration, there is an advantage that the thickness of the light receiving lens 10 can be made sufficiently thin.

FIG. 6 shows an embodiment in which the light-receiving lens 10 is composed of biconvex lens portions L1, L2 and L3. The optical axis (center axis) of the biconvex lens portions L2 and L3 is deviated from the optical axis (center axis) of the biconvex lens portion L1 as in the above-described embodiment.

In this embodiment, the lens portions L1, L2,
L3 incidence surfaces SI1, SI2, SI3 and emission surfaces SO1,
SO2 and SO3 are slightly different from each other. A deviation D between the entrance surface SI1 and the exit surface SO1 (or the entrance surface SI2 and the exit surface SO2) in the lens partial arrangement direction is indicated by D.
That is, in the lens portion L1, its incident surface SI1
The size and position of the emission surface SO1 are determined so that all the light that is incident on and refracted (light shown by the broken line) is necessarily emitted from the emission surface SO1 of the lens portion L1. In other words, the exit surface SO1 is defined so as to cover the area (effective area) through which the light incident from the entrance surface SI1 and refracted passes. The same applies to the other lens portions L2 and L3. This prevents generation of stray light caused by a point incident from the incident surface of one lens portion being emitted from the emitting surface of the other lens portion.

In the case where the detectable distances are required to be set to be equal within the range of the viewing angle (for example, photoelectric sensor), it is preferable that the amount of received light is uniform within the range of the viewing angle as described above. On the other hand, in a laser radar or the like mounted on an automobile and used to detect a preceding vehicle or the like, a long detectable distance is set in a central portion of the visual field centered on the reference optical axis and a peripheral portion of the visual field is set. Then, the detectable distance may be relatively short. In such an application, the light receiving area of the lens portions arranged on both sides is reduced to reduce the light receiving amount.

In FIG. 7, the lens portions L2 and L3 on both sides are centered on the reference optical axis O1 of the lens portion L1 at the center.
Axial displacement amounts of the optical axes (center axes) O2 and O3 of the above from the reference optical axis O1 are x2 and x3, respectively (in the arrangement direction of the lens portions). The distance between the main plane of the lens 10 and the light receiving surface 21 is a. Angles θ2 and θ3 at the center of the visual field of L2 and L3 of the lens portion are expressed by the following equations.

[0034]

## EQU1 ## θ2 = tan ^-1 (x2 / a) Equation 1 θ3 = tan ^-1 (x3 / a) Equation 2

Generally, when the axial displacement amount of the optical axis (center axis) of the i-th lens portion with respect to the reference optical axis O1 is xi,
The angle θi of the visual field center of the i-th lens part is

## EQU2 ## θi = tan ^-1 (xi / a) Equation 3 is obtained.

Viewing angle A of each lens portion L1, L2, L3
Let P1, P2 and P3 be the desired amounts of light received at L1, AL2 and AL3, respectively.
Light receiving area of L2, L3 (area of incident surface) S1, S2, S
3 is determined so as to have a light receiving area ratio S1: S2: S3 proportional to the light receiving amount ratio P1: P2: P3. In the compound lens 10 composed of n lens portions, the light receiving area ratio S1: S2: ...: Sn is determined so as to be proportional to the light receiving amount ratio P1: P2: ...: Pn. Assuming that the length of the light receiving surface 21 (arrangement direction of the lens portions) is d, the viewing angles AL1, AL2, AL3 of the respective lens portions are

## EQU3 ## It is given by tan ^-1 (d / a).

FIG. 8 shows another example of a combination of a light-receiving compound lens and a light-receiving element suitable for a light-receiving optical system of a laser radar. The light-receiving element has a light-receiving surface 21 with a light-receiving lens 10
It is arranged at a position slightly closer to the lens 10 side than the focal position of. The light receiving element may be arranged at a position where the light receiving surface 21 thereof is slightly away from the lens 10 with respect to the focal position of the lens 10.

Due to such an arrangement relationship, the amount of light received by each lens portion L1, L2, L3 changes smoothly at the end of the light receiving area (viewing angle range) by those lens portions, and adjacent light receiving portions are received. Areas partially overlap. This prevents the non-detection zone (a gap between the light receiving areas) and the oversensitivity zone (a large amount of received light overlaps in the two areas).

FIG. 9 shows that the light receiving lens 10 has an optical axis displacement with respect to the reference optical axis O1 (the optical axis of the central lens portion L1).
Alternatively, an example is shown in which the focal length f2 of the lens portion with large optical axis displacement (lens portions L2 or L3 on both sides) is set longer than the focal length f1 of the central lens portion L1. The light receiving surface 21 of the light receiving element is arranged at the light collecting position of the central lens portion L1.

When the incident angle of the light rays incident on the lens portion L2 changes from LT1 to LT2, the focal position of these light rays also changes from PT1 to PT2 due to the off-axis aberration. The locus of change of the focal position is shown by a broken line.
In consideration of such a change of the condensing position, the focal length is set long for the lens portion having the optical axis displaced from the reference optical axis and having the field of view in the area off the center. Is configured so that the incident light is correctly focused on the light receiving surface 21. As a result, it is possible to prevent the amount of received light from decreasing due to the converging spot on the light receiving surface 21 of the light entering from the direction away from the center being blurred.

FIG. 10 also shows a configuration suitable for a light receiving optical system of a laser radar. A laser radar installed in a vehicle requires a wide field of view in the horizontal direction and may have a narrow field of view in the vertical direction. Lens part L that constitutes the lens 10
Reference numerals 1, L2 and L3 denote toric lenses, the focal lengths of which in the horizontal direction (arrangement direction of lens portions) and the vertical direction are different. The light receiving surface of the light receiving element 21 is
A position slightly closer to the lens than the horizontal focus position (see FIG. 8).
The configuration) or is arranged so as to come to a slightly distant position. The position where the light receiving surface 21 is arranged is the vertical focus position (the focused spots are SP1, SP2, S, respectively).
P3). As a result, in the vertical direction the light receiving surface 21
Since the light is focused on the top, a decrease in the amount of received light is prevented.

As shown in FIG. 9, the focal lengths of the lens portions L2 and L3 on both sides having an optical axis displacement with respect to the reference optical axis in either or both of the horizontal direction and the vertical direction are set to the central lens portion. It goes without saying that the focal length of L1 may be set longer than the focal length of L1.

11 and 12 show another example of a light-receiving lens suitable for a laser radar mounted on a vehicle.
This composite light-receiving lens 11 has seven lens parts L11 and L1.
2, L13, L14, L15, L16, L17 are integrally formed. Semicircular lens portions L12 and L13 are arranged on both sides of the central rectangular lens portion L11, and the lens portion L is located at the upper left and lower left of the semicircular lens portion L12.
The lens portions 14 and L15 are arranged at the upper right and lower portions of the lens portion L13, respectively, and the lens portions L16 and L17 are arranged so that there is no gap between the lens portions, thereby forming a rectangular lens 11 as a whole.

FIG. 13 shows the visual field ranges AL11 to AL17 by such lens portions L11 to L17. The lens area that is responsible for the central field of view has a wider light-receiving area, ensuring a detection range over a longer distance. The viewing angle is very wide and there is almost no blind spot in front of the light receiving element 20. In this way, a long detection area (shown by hatching) is formed in front of the light receiving element 20.

14 to 16 show examples of photoelectric sensors. The photoelectric sensor includes a light projecting device and a light receiving device. The light receiving device 22 includes the light receiving lens 10 or 11 and the light receiving element 20 described above. The processing circuit for the received light signal obtained from the light receiving device 22 is the same as that already known.

In the photoelectric sensor 31 shown in FIG. 14, the light projecting device 25 emits substantially uniform light over an appropriate angle range.

In FIG. 15, the projector 26 of the photoelectric sensor 32 is shown.
Is for sweeping the projected light over the angular range of the light receiving area. The projected light may be pulsed light or continuous light.
The projection device 26 is characterized in that light is intensively projected for each sweep angle to obtain a high light reception amount.

In FIG. 16, the projector 27 of the photoelectric sensor 32 is shown.
Is a multi-beam projection device that simultaneously projects a plurality of light beams at appropriate angular intervals over the range of the light receiving area. The light beam may be pulsed light or continuous light. This light projecting device 27 is realized by combining a grating and a light source, or a lens array or prism array and a light source, or by a plurality of light sources. The multi-beam projector has a feature that a large amount of light can be obtained by intensively projecting light without having a movable part.

FIG. 17 shows the structure of the laser radar. The laser radar 40 is mounted on the front of the vehicle 60 as shown in FIG. The laser radar 40 includes a light projecting device 41, a light receiving device, and a signal processing device. The light projecting device 41 projects a pulsed laser beam toward the front of the vehicle. This laser light is swept over a predetermined measurement angle range (light receiving area). Laser light is projected at a constant angular interval in this measurement angle range.

As shown in FIG. 18, for example, a laser light source 51
The pulsed laser light projected from a is reflected by the rotary mirror 52a which is reciprocally rotated at a constant speed in a constant angle range, and is projected through the projection lens.

For example, the measurement angle range is 200 [mrad], and each has a spread of 100 [mrad] to the left and right in the traveling direction of the vehicle. Further, this measurement angle range is divided into 80 at equal angular intervals, and laser light is projected at each angular interval. Laser light will be projected at an angular interval of 2.5 [mrad].

The laser light projected from the light projecting device 41 of the laser radar 40 is reflected by the roadside reflector R provided on the roadside of the road or the vehicle reflector mounted at the rear of the preceding vehicle, and is reflected by the laser radar 40. Come back to. This reflected light is condensed by the light receiving lens 10 included in the light receiving device,
The light is received by the light receiving element 20. The light reception signal of the light receiving element 20 is processed by the signal processing device provided on the printed board 42. At least the light projecting device 41 and the light receiving device may be provided in the front portion of the vehicle 60.

FIG. 20 shows a part of the light emitting device 41 of the laser radar, a part of the light receiving device and a signal processing circuit.
The light projecting device 41 includes a light projector 51, a laser light sweeping device 52, and a sweep angle detecting device 53. A laser light source 51 is provided in the projector 51.
The laser beam sweeping device 52 includes a mirror 52a. The light receiving device includes a light receiver 54, in which the light receiving element 20
Is included.

The light projector 51 repeatedly projects the pulsed laser light at a constant time interval and outputs a light projection timing signal indicating the time when the laser light is emitted. For example, a semiconductor laser light emitting device is suitable for the projector 54 in terms of downsizing of the device and high speed driving. The light projection timing signal is given from the light projector 51 to the distance calculation device 55.

For example, if the measurable distance of the laser light is 150 [m], the time required for the laser light to reciprocate over this distance, that is, (150 [m] ×
2) / (3 × 10 ⁸ [m / s]) = 1 [μs] or more.

The laser beam sweeping device 52 sweeps the laser beam projected by the projector 51 within the measurement angle range. The laser light is
The light is projected radially forward at a constant angle interval (equal angle interval described above) at each projection time interval. The laser beam sweeping device 52 is suitable because it is difficult for a laser beam reflecting mirror that changes its angle at a predetermined cycle to spread the laser beam. A sweep angle position signal indicating the angle at which the laser light is projected is provided from the laser light sweep device 52 to the sweep angle detection device 53.

The sweep angle detection device 53 is a laser light sweep device.
Based on the sweep angle position signal given from 52, the sweep angle θ at which the laser light is projected (based on the direction perpendicular to the traveling direction of the vehicle 60) is calculated. The data representing the calculated sweep angle θ is obtained from the sweep angle detection device 53 and the signal processing circuit.
Given to 56.

The laser light projected from the laser sweep device 52 is reflected by the object OB to be detected (the above-mentioned roadside reflector or vehicle reflector), and the reflected light is received by the light receiver 54.

Upon receiving the reflected light reflected by the object to be detected OB, the light receiver 54 outputs a light reception timing signal indicating the time when the reflected light is received. The reflected light is received from the laser light sweeping device 52 after the laser light is projected until the next laser light is projected. The light reception timing signal is given from the light receiver 54 to the distance calculation device 55.
The light receiver 54 converts the reflected light incident on the light receiving element 20 (for example, a photodiode, a phototransistor, etc.) into an electric signal, and outputs a light reception timing signal when this signal is equal to or more than a predetermined threshold value. Noise is removed by performing threshold processing.

The distance calculation device 55 measures the time interval from the input time of the light projection timing signal supplied from the light projector 51 to the input time of the light reception timing signal supplied from the light receiver 52 to measure the distance to the detected object OB. Calculate d. The data representing the calculated distance d to the detected object is given from the distance calculation device 55 to the signal processing circuit 56.

The vehicle speed sensor 57 is a vehicle speed v (laser radar
The vehicle speed of the vehicle 60 equipped with 40 is detected. Data representing the vehicle speed v is given from the vehicle speed sensor 57 to the signal processing circuit 56.

The signal processing circuit 56 advances based on the sweep angle θ given from the sweep angle detecting device 53, the distance d to the detected object OB given from the distance calculating device 55 and the vehicle speed v given from the vehicle speed sensor 57. It calculates the inter-vehicle distance to the vehicle and performs other processing.

FIG. 19 is a graph showing the sweep angle θ and the distance d given to the signal processing circuit 56. In this way, the position ob of the detected object OB becomes clear on the graph.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a light-receiving compound lens.

FIG. 2 is a perspective view of a light-receiving compound lens.

FIG. 3 shows a light-receiving compound lens and its viewing angle / light-receiving amount characteristics.

4A and 4B show another example of a light-receiving compound lens composed of a Fresnel lens, where FIG. 4A is a front view and FIG. 4B is a sectional view.

FIG. 5 shows a photoelectric sensor having a light receiving optical system.

FIG. 6 is a cross-sectional view of a light-receiving compound lens including a biconvex lens.

FIG. 7 shows a light-receiving compound lens composed of a biconvex lens and its viewing angle / light-receiving amount characteristics.

FIG. 8 shows another configuration example of the light-receiving compound lens and its viewing angle / light-receiving amount characteristic.

FIG. 9 is a cross-sectional view showing another configuration example of the light-receiving compound lens.

FIG. 10 is a perspective view showing another configuration example of a light-receiving compound lens.

FIG. 11 is a front view showing still another configuration example of the light-receiving compound lens.

12 is a perspective view of the light-receiving compound lens shown in FIG.

13 shows a light receiving area of the light receiving compound lens shown in FIG.

FIG. 14 shows an example of a photoelectric sensor.

FIG. 15 shows a beam scan type photoelectric sensor.

FIG. 16 shows a multi-beam type photoelectric sensor.

FIG. 17 shows a configuration of a laser radar.

FIG. 18 shows a configuration for sweeping a laser beam.

FIG. 19 is a graph showing a detected object detected by a laser radar.

FIG. 20 is a block diagram showing an electrical configuration of a laser radar.

FIG. 21 is a perspective view showing a vehicle equipped with a laser radar.

FIG. 22 shows a light receiving area of a conventional photoelectric sensor.

FIG. 23 shows a conventional configuration for expanding a light receiving area.

FIG. 24 shows a conventional configuration for expanding the light receiving area.

FIG. 25 shows a conventional defocused light receiving optical system and its viewing angle / light receiving amount characteristic.

FIG. 26 shows a conventional defocused light receiving optical system and its viewing angle / light receiving amount characteristics.

[Explanation of symbols]

 10, 11 Complex lens for receiving light L1, L2, L3, L11 to L17 Lens part 20 Light receiving element 21 Light receiving surface 22 Light receiving device 25, 26, 27, 41 Projector O1, O2, O3 Optical axis 30, 31, 32, 33 Photoelectric sensor SI1-SI3 Incident surface SO1-SO3 Exit surface 40 Laser radar 60 Vehicle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G01V 8/14

Claims (17)

[Claims] 1. A plurality of lens portions are combined so that their optical axes are located at different positions, and incident light having different incident angles from the respective light receiving areas shared by the respective lens portions is collected at one place. A light-receiving lens configured to emit light. 2. The light-receiving lens according to claim 1, wherein the lens portion is a convex lens. 3. The light-receiving lens according to claim 1, wherein the lens portion is a Fresnel lens. 4. The light-receiving lens according to claim 1, which is integrally molded. 5. The lens portion according to claim 1, wherein the lens portion is composed of a biconvex lens, and the corresponding lens portion has an emission surface that covers an area of light incident on the incident surface of each lens portion. The light-receiving lens according to any one of items. 6. The light-receiving lens according to claim 1, wherein the lens portion located at the center has a larger incident surface area and the peripheral portion has a smaller incident surface area. 7. At least one of the lens portions has a circular peripheral edge, and another lens portion is arranged in contact with the circular peripheral edge, and is configured to have a rectangular peripheral edge as a whole. The light-receiving lens according to claim 1. 8. The light-receiving lens according to claim 1, wherein the plurality of lens portions have the same focal length. 9. The light-receiving lens according to claim 1, wherein a focal length of a lens portion located in the periphery is longer than a focal length of a lens portion located in the center. 10. A focal length in one direction of the plurality of lenses and a focal length in a direction orthogonal thereto are different.
Item 10. The light-receiving lens according to any one of items 1 to 9. 11. A light receiving device using the light receiving lens according to claim 1, further comprising a light receiving element arranged at a focal position of a plurality of lens parts or a lens part having the shortest focal length. apparatus. 12. The light-receiving element according to claim 1, further comprising a light-receiving element arranged at a position closer to the light-receiving lens or farther from the light-receiving lens from the focal position of the plurality of lens parts or the lens part having the shortest focal length. 10. A light receiving device using the light receiving lens described in any one of 10. 13. A photoelectric sensor comprising the light receiving device according to claim 11 or 12, and a light projecting device having a multi-beam light source. 14. A photoelectric sensor comprising the light receiving device according to claim 11 or 12, and a scan beam projecting device for sweeping projection light. 15. A photoelectric sensor including the light receiving device according to claim 11. 16. A laser radar comprising the light receiving device according to claim 11. 17. A vehicle equipped with the laser radar according to claim 16.