CN105277931A - Multi-beam collimation emission and receiving system for laser radar and lens thereof - Google Patents

Abstract

The invention belongs to an optical system, and in particular relates to a laser radar multi-beam collimating transmitting and receiving system and a lens thereof. It includes a collimating emission lens and a matching focusing receiving lens. The collimating emitting lens and the focusing receiving lens are set in the bracket. The bracket of the detector can ensure the synchronous movement of the collimating transmitting lens and the focusing receiving lens. The effect of the present invention is: the collimated emission of the laser beam in the 40° field of view and the focused detection of the parallel beam in the 40° field of view can be realized. After collimation, the divergence angle of the beam can be achieved <3mrad, and the spot size after focusing can be <0.2mm; At the same time, the combined array of D-type lenses can make the transmitting optical path and receiving optical path close to parallel, so that the blind area can be reduced to nearly zero; the transmitting and receiving adopt the same lens structure and parameters, the structure is simple, the manufacturing is simple, the cost is low, and it can be mass-produced.

Description

A multi-beam collimated transmitting and receiving system for laser radar and its lens

technical field

The invention belongs to an optical system, and in particular relates to a laser radar multi-beam collimating transmitting and receiving system and a lens thereof.

Background technique

Lidar is an extended application of laser ranging technology. It can be used in combination with inertial measurement systems and satellite positioning systems to obtain not only the location information of target objects, but also target reflection spectrum information, which can be used for ranging, speed and target identify. The basic working principle of the laser radar is: within a certain field of view, the laser beam is scanned and emitted to the target object, and the laser beam reflected by the target is received by the photoelectric element, and the time difference or phase shift of the laser beam from emission to reception is measured to obtain the target object. Combined with its own attitude information and position information, the position of the target object can be calculated.

There are two main imaging methods for direct detection lidar: one is to use a unit detector, which only detects one pixel at a time, combined with mechanical scanning to complete the detection of other dimensions; the other is to use an area array detector to detect all pixels at a time, Although this method has a simple structure, it requires high laser power and cannot use a high-sensitivity APD detector. Therefore, the current lidar mostly uses an area scanning system.

The transmitting and receiving optical system is an important part of the laser radar. The laser beam emitted by the semiconductor laser has different divergence angles in the two directions perpendicular to and parallel to the junction plane, and the shape of the spot is irregular (such as generally elliptical or long). There are shortcomings such as inherent astigmatism, so the beam output by the semiconductor laser must be collimated to improve the quality of the output beam. In order to enable lidar to detect as far away as possible, a high-performance focusing and receiving optical system is required.

For the lidar of the current surface scanning system, most of its transmitting and receiving lenses only collimate and focus on a single beam, and realize 3D imaging through galvanometer scanning combined with a rotating mechanism. The limitation of this method is that the scanning speed of the galvanometer is low. In applications that require high-speed real-time imaging (such as unmanned vehicle barriers), it is necessary to involve a lens that can meet the requirements of multi-beam collimation for transmitting and receiving. At the same time, since the emitting light path and receiving light path of the existing lidar lens are separated, this will cause parallax problems, and a near blind area and a far blind area will be generated at positions close to and far from the lens, which directly affect the detection effect of the lidar.

Contents of the invention

The purpose of the present invention is to provide a laser radar multi-beam collimation transmitting and receiving system and its lens for the defects of the prior art.

The present invention is achieved like this: a kind of collimation emission lens is characterized in that: comprise the lens barrel that is arranged in sequence in the support, receive first lens, receive lens spacer ring, receive second lens, receive the 3rd lens, and A filter set outside the bracket and on the same optical path as the receiving third lens.

As in the above collimating emission lens, wherein, the receiving first lens is a biconvex lens, which includes a first curved surface and a second curved surface with different curvature radii, and the receiving second lens and the receiving third lens are biconcave respectively and the biconvex lens, receiving the second lens includes a third curved surface and a fourth curved surface with different curvature radii, receiving the third lens includes a fifth curved surface and a sixth curved surface with different curvature radii, receiving the second lens and receiving the third lens to form a cement mirror, the fourth curved surface and the fifth curved surface are glued surfaces.

As in the above collimating emission lens, wherein, the material of the receiving first lens is SF1, the radius of curvature R1 of the first curved surface=46.3mm, the radius of curvature R2=-329.6mm of the second curved surface, the first curved surface and the second curved surface The surface interval of the curved surface is the central thickness of the first curved surface d1=5mm, the first curved surface and the second curved surface are coated with anti-reflection coating, the reflectivity is <5%, the material receiving the second lens is SF1, and the radius of curvature of the third curved surface R3= -45.08mm, the radius of curvature of the fourth curved surface R4 = 32.5mm, the distance between the third curved surface and the fourth curved surface is the center thickness of the first curved surface d1 = 3mm, the third curved surface is coated with an anti-reflective coating, and the reflectivity is <5%. The material receiving the third lens is BK7, the radius of curvature of the fifth curved surface R5=32.5mm, the radius of curvature of the sixth curved surface R6=-32.4mm, the distance between the fifth curved surface and the sixth curved surface is the central thickness d1 of the first curved surface =8mm, the fifth curved surface and the sixth curved surface are coated with anti-reflection coating, and the reflectivity is <5%.

A focus-receiving lens includes a lens barrel, a first emitting lens, a spacer ring 8 for the emitting lens, a second emitting lens, and a third emitting lens arranged in sequence in a bracket.

As shown above, a focus receiving lens, wherein, the first emitting lens is a biconvex lens, which includes a first curved surface and a second curved surface with different curvature radii, and the second emitting lens and the third emitting lens are bi-convex lenses respectively. Concave and double-convex lenses, the emitting second lens includes a third curved surface and a fourth curved surface with different curvature radii, the emitting third lens includes a fifth curved surface and a sixth curved surface with different curvature radii, the emitting second lens and the emitting third lens are formed For gluing mirrors, the fourth curved surface and the fifth curved surface are gluing surfaces.

A focusing and receiving lens as shown above, wherein, the material of the emitting first lens is SF1, the curvature radius R1 of the first curved surface=46.3mm, the curvature radius R2=-329.6mm of the second curved surface, the first curved surface and the second curved surface The surface interval of the two curved surfaces is the central thickness of the first curved surface d1=5mm, the first curved surface and the second curved surface are coated with anti-reflection coating, the reflectivity is <5%, the material of the second lens is SF1, and the radius of curvature of the third curved surface is R3 =-45.08mm, the radius of curvature of the fourth curved surface R4=32.5mm, the distance between the third curved surface and the fourth curved surface is the center thickness of the first curved surface d1=3mm, the third curved surface is coated with anti-reflection coating, and the reflectivity is <5% , the material for emitting the third lens is BK7, the radius of curvature R5 of the fifth curved surface is 32.5mm, the radius of curvature of the sixth curved surface R6=-32.4mm, the distance between the fifth curved surface and the sixth curved surface is the center thickness of the first curved surface d1=8mm, the fifth curved surface and the sixth curved surface are coated with anti-reflection coating, and the reflectivity is <5%.

A multi-beam collimated transmitting and receiving system for laser radar, which includes a collimating transmitting lens and a matching focusing receiving lens, the collimating transmitting lens and the focusing receiving lens are arranged in a bracket, and the collimating transmitting lens mirror A laser is set on one side of the barrel, and a detector is set on the side of the focusing receiving lens barrel. This bracket can ensure the synchronous movement of the collimating emitting lens and the focusing receiving lens.

A multi-beam collimated transmitting and receiving system for lidar as described above, wherein the multi-beam collimating transmitting and receiving system for lidar includes an array composed of multiple collimating transmitting lenses and multiple focusing receiving lenses , the plurality of collimated emission lenses are arranged on the arc surface, the radius of the arc surface is 109mm, and a plurality of focus receiving lenses are arranged on the arc surface, the radius of the arc surface is 88mm, and the collimation emission lens is formed The arc of the arc is the same as the center of the arc formed by the focusing receiving lens, and the collimating emitting lens and focusing receiving lens can be arranged arbitrarily within the range of the central angle of 40°.

The effect of the present invention is: the collimated emission of the laser beam in the 40° field of view and the focused detection of the parallel beam in the 40° field of view can be realized. After collimation, the beam divergence angle can be less than 3mrad, and the spot size after focusing can be less than 0.2mm; At the same time, the combined array of D-type lenses can make the transmitting optical path and receiving optical path close to parallel, so that the blind area can be reduced to close to zero. The simulation results are shown in Figure 2 and Figure 3; the same lens structure and parameters are used for transmitting and receiving, The structure is simple, the manufacture is convenient, the cost is low, and it can be produced in batches.

Description of drawings

Fig. 1 is the structure schematic diagram that the present invention provides laser radar with multi-beam collimation transmitting and receiving system;

Fig. 2 is the ray tracing diagram of the collimating emission lens of the present invention;

Fig. 3 is a ray tracing diagram of the focus receiving lens of the present invention.

In the figure: 1. Lens barrel, 2. Receiving the first lens, 3. Receiving the lens spacer, 4. Receiving the second lens, 5. Receiving the third lens, 6. Partition, 7. Emitting the first lens, 8. Emitting lens spacer, 9. Emitting second lens, 10. Emitting third lens, 11. Detector, 12. Laser, 13. Target, 14. Optical filter.

detailed description

As shown in Figure 1, a multi-beam collimated transmitting and receiving system for lidar includes a collimating transmitting lens and a matching focusing receiving lens, the collimating transmitting lens and focusing receiving lens are arranged in a bracket, and A laser 12 is arranged on one side of the lens barrel of the collimating emitting lens, and a detector 11 is arranged on the side of the barrel of the focusing receiving lens. This bracket can ensure that the collimating emitting lens and the focusing receiving lens move synchronously.

The multi-beam collimated transmitting and receiving system for lidar includes an array composed of multiple collimating transmitting lenses and multiple focusing receiving lenses, and the transmitting lens array and receiving lens array are "back-to-back" separated by a partition. The D-type transmitting and receiving lens array is cut from the edge of a circular lens with a thickness of 0.25D to form a D-type lens array.

The plurality of collimated emission lenses are arranged on the curved curved surface, the radius of the curved curved surface is 109mm, and a plurality of focusing receiving lenses are arranged on the curved curved surface, the radius of the curved curved surface is 88mm, and the collimated emission lens constitutes The center of the arc is the same as that formed by the focusing receiving lens, and the collimating transmitting lens and focusing receiving lens can be arranged arbitrarily within the range of the central angle of 40°.

A kind of collimating emission lens comprises the lens barrel 1 that is arranged in sequence in the support, receives the first lens 2, receives the lens spacer ring 3, receives the second lens 4, receives the third lens 5, and is arranged on the outside of the support and is connected with the receiving lens. The third lens 5 is on the same optical path as the optical filter 14 .

The receiving first lens 2 is a double-convex lens, which includes a first curved surface and a second curved surface with different curvature radii. The receiving second lens 4 and the receiving third lens 5 are biconcave and biconvex lenses respectively, the receiving second lens 4 includes a third curved surface and a fourth curved surface with different curvature radii, and the receiving third lens 5 includes a fifth curved surface with different curvature radii. The curved surface and the sixth curved surface, receiving the second lens 4 and receiving the third lens 5 form a cemented mirror, and the fourth curved surface and the fifth curved surface are cemented surfaces.

The material receiving the first lens 2 is SF1, the radius of curvature R1 of the first curved surface is 46.3mm, the radius of curvature R2 of the second curved surface is R2=-329.6mm, and the distance between the first curved surface and the second curved surface is the distance of the first curved surface Central thickness d1 = 5mm. The first curved surface and the second curved surface are coated with anti-reflection coating, the reflectivity is <5%, the material receiving the second lens 4 is SF1, the curvature radius R3 of the third curved surface=-45.08mm, and the curvature radius R4 of the fourth curved surface=32.5mm , the distance between the third curved surface and the fourth curved surface is the central thickness d1 of the first curved surface = 3 mm. The third curved surface is coated with anti-reflection coating, the reflectivity is <5%, the material receiving the third lens 5 is BK7, the curvature radius R5 of the fifth curved surface is 32.5mm, the curvature radius of the sixth curved surface is R6=-32.4mm, and the fifth curved surface The surface distance from the sixth curved surface is the central thickness d1 of the first curved surface = 8mm. The fifth curved surface and the sixth curved surface are coated with anti-reflection coating, and the reflectivity is less than 5%.

A focusing and receiving lens includes a lens barrel 1 , a first transmitting lens 7 , a spacer ring 8 for the transmitting lens, a second transmitting lens 9 , and a third transmitting lens 10 arranged in sequence in a bracket.

The emitting first lens 7 is a double-convex lens, which includes a first curved surface and a second curved surface with different curvature radii. The emitting second lens 9 and the emitting third lens 10 are biconcave and biconvex lenses respectively. The emitting second lens 9 includes a third curved surface and a fourth curved surface with different curvature radii. The emitting third lens 10 includes a fifth curved surface with different curvature radii. The curved surface and the sixth curved surface, the emitting second lens 9 and the emitting third lens 10 form a cemented mirror, and the fourth curved surface and the fifth curved surface are cemented surfaces.

The material of the first emitting lens 7 is SF1, the radius of curvature R1 of the first curved surface is 46.3mm, the radius of curvature R2 of the second curved surface is R2=-329.6mm, and the distance between the first curved surface and the second curved surface is the distance of the first curved surface. Central thickness d1 = 5mm. The first curved surface and the second curved surface are coated with anti-reflection coating, the reflectivity is <5%, the material of the emitting second lens 9 is SF1, the radius of curvature R3 of the third curved surface=-45.08mm, and the radius of curvature R4 of the fourth curved surface=32.5mm , the distance between the third curved surface and the fourth curved surface is the central thickness d1 of the first curved surface = 3 mm. The third curved surface is coated with an anti-reflection coating, the reflectivity is <5%, the material for emitting the third lens 10 is BK7, the curvature radius R5 of the fifth curved surface is 32.5mm, the curvature radius R6 of the sixth curved surface is R6=-32.4mm, and the fifth curved surface is The surface distance from the sixth curved surface is the central thickness d1 of the first curved surface = 8mm. The fifth curved surface and the sixth curved surface are coated with anti-reflection coating, and the reflectivity is less than 5%.

The lens parameters used in this application are shown in the table below

The transmitting and receiving lens of the present invention is mainly used for the collimation of the transmitting beam of the laser radar and the focusing of the reflected echo signal of the target. Multiple laser beams with different angles are emitted by multiple lasers with a wavelength of 903nm, which are collimated by the transmitting lens and irradiate the target 13. After the reflected light is filtered by the filter sheet 14 to filter out the stray light and background light, after being focused by the receiving lens, it is received by the detectors at corresponding angles respectively to realize the collimation and focusing functions of the laser radar lens. In this application, the light filtering The center wavelength of the chip is 905nm, and the bandwidth is 20nm. The detectors correspond to the lasers one by one without interfering with each other. A detector only receives the echo signal of the laser emitted by the corresponding laser and reflected by the target.

Claims (8)

1. a collimated emission camera lens, it is characterized in that: comprise arrange in turn in the bracket lens barrel (1), receive the first lens (2), receive camera lens spacer ring (3), receive the second lens (4), receive the 3rd lens (5), and be arranged on support outer and with reception the 3rd lens (5) optical filter in same light path (14).

2. a kind of collimated emission camera lens as claimed in claim 1, it is characterized in that: described reception first lens (2) are lenticular lens, it comprises radius-of-curvature and arranges different first surfaces and the second curved surface, receive the second lens (4) and receive the 3rd lens (5) and be respectively concave-concave and biconvex lens, receive the second lens (4) to comprise radius-of-curvature and arrange different 3rd curved surface and the 4th curved surface, receive the 3rd lens (5) to comprise radius-of-curvature and arrange the 5th different curved surfaces and the 6th curved surface, receive the second lens (4) and receive the 3rd lens (5) and form gummed mirror, 4th curved surface and the 5th curved surface are cemented surface.

3. a kind of collimated emission camera lens as claimed in claim 2, it is characterized in that: the material of described reception first lens (2) is SF1, the radius of curvature R 1=46.3mm of first surface, the radius of curvature R 2=-329.6mm of the second curved surface, the interval, face of first surface and the second curved surface and the center thickness d1=5mm of first surface, first surface, second curved surface plating anti-reflection film, reflectivity <5%, the material receiving the second lens (4) is SF1, the radius of curvature R 3=-45.08mm of the 3rd curved surface, the radius of curvature R 4=32.5mm of the 4th curved surface, the interval, face of the 3rd curved surface and the 4th curved surface and the center thickness d1=3mm of first surface, 3rd curved surface plating anti-reflection film, reflectivity <5%, the material receiving the 3rd lens (5) is BK7, the radius of curvature R 5=32.5mm of the 5th curved surface, the radius of curvature R 6=-32.4mm of the 6th curved surface, the interval, face of the 5th curved surface and the 6th curved surface and the center thickness d1=8mm of first surface, 5th curved surface, 6th curved surface plating anti-reflection film, reflectivity <5%.

4. focus on and receive a camera lens, it is characterized in that: comprise arrange in turn in the bracket lens barrel (1), launch the first lens (7), launch camera lens spacer ring 8, launch the second lens (9), launch the 3rd lens (10).

5. as Suo Shi claim 4, a kind of focusing receives camera lens, it is characterized in that: described transmitting first lens (7) are lenticular lens, it comprises radius-of-curvature and arranges different first surfaces and the second curved surface, launch the second lens (9) and launch the 3rd lens (10) and be respectively concave-concave and biconvex lens, launch the second lens (9) to comprise radius-of-curvature and arrange different 3rd curved surface and the 4th curved surface, launch the 3rd lens (10) to comprise radius-of-curvature and arrange the 5th different curved surfaces and the 6th curved surface, launch the second lens (9) and launch the 3rd lens (10) and form gummed mirror, 4th curved surface and the 5th curved surface are cemented surface.

6. a kind of focusing receives camera lens as stated in claim 5, it is characterized in that: the material of described transmitting first lens (7) is SF1, the radius of curvature R 1=46.3mm of first surface, the radius of curvature R 2=-329.6mm of the second curved surface, the interval, face of first surface and the second curved surface and the center thickness d1=5mm of first surface, first surface, second curved surface plating anti-reflection film, reflectivity <5%, the material launching the second lens (9) is SF1, the radius of curvature R 3=-45.08mm of the 3rd curved surface, the radius of curvature R 4=32.5mm of the 4th curved surface, the interval, face of the 3rd curved surface and the 4th curved surface and the center thickness d1=3mm of first surface, 3rd curved surface plating anti-reflection film, reflectivity <5%, the material launching the 3rd lens (10) is BK7, the radius of curvature R 5=32.5mm of the 5th curved surface, the radius of curvature R 6=-32.4mm of the 6th curved surface, the interval, face of the 5th curved surface and the 6th curved surface and the center thickness d1=8mm of first surface, 5th curved surface, 6th curved surface plating anti-reflection film, reflectivity <5%.

7. a laser radar multiple beam collimated emission and receiving system, it is characterized in that: the focusing reception camera lens comprising collimated emission camera lens and match with it, collimated emission camera lens and focusing receive camera lens and arrange in the bracket, laser instrument (12) is set in collimated emission lens barrel side, detector (11) this support is set in focusing reception lens barrel side and can ensures collimated emission camera lens and focus on reception camera lens to be synchronized with the movement.

8. a kind of laser radar multiple beam collimated emission as claimed in claim 7 and receiving system, it is characterized in that: described laser radar multiple beam collimated emission and receiving system comprise multiple collimated emission camera lens and multiple focusing and receive the array that camera lens forms, described multiple collimated emission camera lens is arranged on arc-shaped curved surface, the radius of arc-shaped curved surface is 109mm, multiple focusing receives camera lens and is arranged on arc-shaped curved surface, the radius of arc-shaped curved surface is 88mm, the arc that collimated emission camera lens is formed is identical with focusing on the center of circle receiving the arc that camera lens is formed, and collimated emission camera lens can be arranged arbitrarily in scope within 40 °, central angle and focus on and receive camera lens.