Circuit for laser radar, laser radar, design method and manufacturing method

Abstract

The invention provides a circuit used for a laser radar, the laser radar, a design method of the circuit used for the laser radar and a manufacturing method of the circuit used for the laser radar, the circuit used for the laser radar comprises a grounding end, a circuit device, an elastic sheet and a resonant capacitor, and the elastic sheet and the resonant capacitor are connected in series between the grounding end and the circuit device. And the circuit device is electrically connected with the grounding end. According to the embodiment of the invention, the elastic sheet and the resonant capacitor which are connected in series are arranged between the grounding end and the circuit device, the parasitic inductor and the resonant capacitor of the elastic sheet generate series resonance within a certain frequency range, and the resonant capacitor and the elastic sheet jointly provide low-impedance connection to form a backflow path. The impedance of the resonant capacitor can be partially offset with the impedance generated by the spurious inductance of the elastic sheet, thereby reducing the impedance in a backflow path, reducing the influence of high frequency on the impedance of the backflow path, and being suitable for a high-frequency electromagnetic wave environment of the laser radar.

Description

Technical Field

[0001] The present invention generally relates to the field of laser radar technology, and in particular to a circuit for laser radar, a laser radar, a design method for a circuit for laser radar, and a manufacturing method for a circuit for laser radar. Background Art

[0002] The EMC (Electromagnetic Compatibility) of electronic products is a very important quality indicator, which is not only related to the working reliability and safety of the product itself, but also may affect the normal operation of other equipment and systems. According to the design requirements of EMC, it is necessary to establish a low-impedance connection to form a low-impedance return path as a transmission path for electromagnetic waves, so as to reduce the radiation of various devices, circuits and other components in the circuit from the radiation path (for example, through the air as a transmission path) to the outside, causing electromagnetic interference.

[0003] In conventional designs, spring clips are usually used to provide low-impedance connections, with the two ends of the spring clips connected to the ground terminal of the circuit board and the circuit components respectively. The smaller the impedance that the spring clip can provide, the less interference radiation transmitted outward through the radiation path. Regardless of whether the spring clip is a standard part or a customized part, the conductive material properties of the spring clip and its own structure will cause the spring clip to have parasitic inductance. Parasitic inductance is an inherent property of the spring clip and is difficult to change.

[0004] The impedance Z that the spring can provide can be expressed as follows:

[0005] Z=2πfL,

[0006] Where L represents the parasitic inductance of the spring, which can be considered as a fixed value in the above formula, and f represents the frequency. According to the above formula, when the parasitic inductance L cannot be changed, the greater the frequency f, the greater the impedance Z, that is, under the influence of high frequency, the impedance of the spring increases, and the effect of improving electromagnetic compatibility becomes smaller.

[0007] However, laser radar products contain a large number of high-speed integrated circuits or high-frequency electronic components, which will produce serious high-frequency interference, and the ability of shrapnel to provide low-impedance connection in a high-frequency electromagnetic wave environment is limited. This leads to limited effectiveness of laser radar when using traditional electromagnetic compatibility design. Therefore, it is necessary to provide a new circuit design based on the characteristics of laser radar.

[0008] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the prior art in the field. Summary of the invention

[0009] In view of one or more defects in the prior art, the present invention provides a circuit for laser radar, comprising:

[0010] Ground terminal;

[0011] Circuit devices;

[0012] Shrapnel and resonant capacitor,

[0013] The spring and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal.

[0014] According to one aspect of the present invention, the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit.

[0015] According to one aspect of the present invention, the resonant capacitor is connected in series between the elastic piece and the ground terminal.

[0016] According to one aspect of the present invention, the circuit device comprises a metal structure, the metal structure is arranged opposite to the ground terminal, and the spring is arranged between the ground terminal and the metal structure and abuts against the metal structure.

[0017] According to one aspect of the present invention, the circuit further comprises a circuit board, wherein the ground terminal and the resonant capacitor are arranged on the circuit board, and the resonant capacitor is connected to the ground terminal and the spring respectively.

[0018] According to one aspect of the present invention, the resonant capacitor comprises a chip ceramic capacitor.

[0019] According to one aspect of the present invention, the circuit also includes a circuit board having an adjacent layer constituting the grounding terminal, wherein the spring is soldered to the adjacent layer via a soldering pad, and the resonant capacitor is formed between the copper sheet where the soldering pad is located and the adjacent layer.

[0020] According to one aspect of the present invention, the circuit further comprises an integrated circuit, wherein at the frequency of electromagnetic radiation of the integrated circuit, the resonant capacitor resonates with the parasitic inductance of the spring.

[0021] According to one aspect of the present invention, the present invention further includes a laser radar, the laser radar comprising:

[0022] A circuit for a laser radar, the circuit comprising a ground terminal, a circuit device, a spring and a resonant capacitor, wherein the spring and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal;

[0023] A transmitting unit, wherein the transmitting unit is configured to transmit a detection light beam;

[0024] A receiving unit, wherein the receiving unit is configured to receive an echo generated after the detection light beam is reflected by an obstacle and convert the echo into an electrical signal;

[0025] A processing unit is integrated on the circuit and configured to obtain the position and / or reflectivity of the obstacle according to the electrical signal of the echo.

[0026] According to one aspect of the present invention, the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit.

[0027] According to one aspect of the present invention, the resonant capacitor is connected in series between the elastic piece and the ground terminal.

[0028] According to one aspect of the present invention, the circuit further includes an integrated circuit, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the electromagnetic radiation frequency of the integrated circuit.

[0029] According to one aspect of the present invention, the electromagnetic radiation frequency of the integrated circuit is a range value, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the maximum value or average value of the range value of the electromagnetic radiation frequency of the integrated circuit.

[0030] According to one aspect of the present invention, the present invention also includes a design method for a circuit for a laser radar, the circuit including a ground terminal, a circuit device, a spring and a resonant capacitor, the spring and the resonant capacitor are connected in series between the ground terminal and the circuit device; the design method includes:

[0031] S101: Obtain the frequency of the interference source of the circuit;

[0032] S102: Obtaining the parasitic inductance of the spring; and

[0033] S103: Determine the capacitance value of the resonant capacitor according to the frequency of the interference source and the parasitic inductance of the spring to reduce the impedance between the circuit device and the ground terminal at the frequency.

[0034] According to one aspect of the present invention, the resonant capacitor is connected in series between the elastic piece and the ground terminal.

[0035] According to one aspect of the present invention, the present invention also includes a method for manufacturing a circuit for a laser radar, wherein the circuit includes a ground terminal, and the manufacturing method includes:

[0036] S201: providing circuit components;

[0037] S202: providing a spring and a resonant capacitor; and

[0038] S203: Connect the spring and the resonant capacitor in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal.

[0039] According to one aspect of the present invention, the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit.

[0040] According to one aspect of the present invention, the resonant capacitor is connected in series between the elastic piece and the ground terminal.

[0041] According to one aspect of the present invention, the circuit further includes an integrated circuit, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the electromagnetic radiation frequency of the integrated circuit.

[0042] According to one aspect of the present invention, the electromagnetic radiation frequency of the integrated circuit is a range value, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the maximum value or average value of the range value of the electromagnetic radiation frequency of the integrated circuit.

[0043] Compared with the prior art, the embodiment of the present invention provides a circuit for laser radar, in which a series spring and a resonant capacitor are arranged between the ground terminal and the circuit device, and the parasitic inductance of the spring and the resonant capacitor generate series resonance within a certain frequency range, and the resonant capacitor and the spring together provide a low-impedance connection to form a return path. The impedance of the resonant capacitor can partially offset the impedance generated by the parasitic inductance of the spring, reduce the impedance in the return path, and reduce the influence of high frequency on the impedance of the return path, which is suitable for the high-frequency environment of the laser radar.

[0044] The present invention also includes an embodiment of a laser radar, which uses the circuit in the aforementioned embodiment and is suitable for the high-frequency environment of the laser radar. It can improve the electromagnetic compatibility performance of the laser radar, thereby improving the working reliability and safety of the laser radar.

[0045] The present invention also includes an embodiment of a circuit design method, wherein the circuit can be applied to a laser radar, and the capacitance value of the resonant capacitor is determined according to the frequency of the interference source in the circuit and the parasitic inductance of the shrapnel, so that the shrapnel and the resonant capacitor connected in series can provide a low-impedance connection to form a return path, which can reduce the outward radiation of interference radiation in the circuit and is suitable for the high-frequency environment of the laser radar.

[0046] The present invention also includes an embodiment of a method for manufacturing a circuit, wherein the circuit is applied in a laser radar, the circuit has a ground terminal, and provides a circuit device, a spring and a resonant capacitor. The spring and the resonant capacitor are connected in series between the ground terminal and the circuit device, and electromagnetic radiation can be transmitted to the ground terminal through a loop of the spring and the resonant capacitor, thereby reducing the electromagnetic radiation of the laser radar, and the circuit is suitable for the high-frequency working environment of the laser radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0048] Figure 1a It is a schematic diagram of a circuit for low impedance connection of an existing spring;

[0049] Figure 1b It is a structural schematic diagram of the existing low-impedance connection of springs;

[0050] Figure 1c yes Figure 1a Schematic diagram of radiated emission test results of the circuit shown in;

[0051] Figure 1d yes Figure 1a The frequency-impedance curve of the spring in the circuit shown in FIG.

[0052] Figure 1e This is a schematic diagram of the parasitic inductance simulation of the shrapnel;

[0053] Figure 2 is a circuit diagram of a circuit in one embodiment of the present invention;

[0054] Figure 3 is a schematic diagram of the structure of a circuit in one embodiment of the present invention;

[0055] Figure 4 is a schematic structural diagram of a circuit in another embodiment of the present invention;

[0056] Figure 5 is a schematic diagram of radiation emission test results of a circuit in one embodiment of the present invention;

[0057] Figure 6 is a frequency-impedance curve diagram of a return path in one embodiment of the present invention;

[0058] Figure 7 is a block diagram of a laser radar in one embodiment of the present invention;

[0059] Figure 8 is a flow chart of a method for designing a circuit for a laser radar in one embodiment of the present invention;

[0060] Fig. 9 It is a flowchart of a method for manufacturing a circuit for a laser radar in one embodiment of the present invention. DETAILED DESCRIPTION

[0061] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0062] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0065] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0066] The embodiments of the present invention are described below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0067] The principle of electromagnetic compatibility design is to establish a return path with an impedance much smaller than the radiation path (i.e. the path for radiating electromagnetic waves outward) so that most of the generated electromagnetic waves are grounded through the return path, avoiding outward radiation and generating strong electromagnetic interference. Figure 1a and Figure 1b The figure shows the existing situation that a spring is set between the ground terminal and the circuit device to provide electrical connection. The two ends of the spring are respectively connected to the ground terminal and the circuit device to achieve electrical connection between the circuit device and the ground terminal. However, in a high-frequency electromagnetic wave environment, the spring has its own parasitic inductance, which causes its impedance to increase as the frequency of the electromagnetic wave increases. Figure 1e As shown in the figure, taking the spring structure as an example, the parasitic inductance and parasitic resistance of the spring at different frequencies can be obtained by using the three-dimensional electromagnetic field simulation software, where ACL represents the parasitic inductance of the spring, and ACR represents the parasitic resistance of the spring. Figure 1e It can be clearly found that with the increase of frequency, the parasitic inductance ACL does not change much, but the parasitic resistance ACR of the spring increases significantly, which leads to the increase of the return impedance Z of the return path. Correspondingly, the return impedance in the return path becomes larger, the electromagnetic waves radiated outward through the radiation path increase, and the electromagnetic compatibility decreases.

[0068] Figure 2 The specific form of the circuit 1 for laser radar according to the embodiment of the present invention is shown below. Figure 2 A circuit 1 for a laser radar is described.

[0069] The circuit 1 includes a ground terminal 10, a circuit device 20, a spring 30 and a resonant capacitor 40, wherein the ground terminal 10 is not limited to the actual earth or neutral line, and can be connected to the outer casing of some equipment or the entire laser radar, or to a wire with a reference potential of zero in the circuit system, etc. It can be specifically designed according to the circuit design of the laser radar, the location and application of the circuit 1, etc.

[0070] The circuit device 20 may be other components in the laser radar, for example, a metal structure. Figure 2 As shown, the spring 30 and the resonant capacitor 40 are connected in series between the ground terminal 10 and the circuit device 20 to realize the electrical connection between the circuit device 20 and the ground terminal 10. The purpose is to reduce the impedance between the circuit device 20 and the ground terminal 10, form a return path (electromagnetic waves return to the ground terminal 10), and make the impedance in the return path much smaller than the impedance of the radiation path (electromagnetic waves radiate to the outside through the air path), thereby reducing the electromagnetic waves radiated outward through the radiation path and avoiding electromagnetic interference to other components or equipment.

[0071] The spring 30 and the resonant capacitor 40 in this embodiment are connected in series between the ground terminal 10 and the circuit device 20. In the embodiment of the present invention, the impedance of the spring 30 and the resonant capacitor 40 connected in series, that is, the return impedance in the return path can be expressed as follows:

[0072]

[0073] In the above formula, Z represents the return impedance, L represents the parasitic inductance of the spring 30, and C represents the capacitance value of the resonant capacitor 40. According to the above formula, the return impedance Z does not change monotonically with the frequency f. At a specific frequency f, by changing the capacitance value C of the resonant capacitor 40, the return impedance Z has a minimum value. Specifically, according to the actual frequency of the interference source in the circuit 1, that is, when the frequency f in the above formula is known, the return impedance Z can be reduced by selecting a suitable capacitance value C of the resonant capacitor 40, forming a low-impedance connection between the ground terminal 10 and the circuit device 20, thereby reducing the electromagnetic waves radiated outward by the circuit 1.

[0074] Radiated emission testing is a test method to evaluate the electromagnetic radiation intensity of electronic products, which is performed by receiving the electromagnetic wave intensity in the test radiation path. In the case of traditional shrapnel providing low impedance connection, such as Figure 1eAs shown, after the frequency increases, the impedance of the spring increases, resulting in an increase in the impedance of the return path, and the impedance of the return path cannot be kept much smaller than the impedance of the radiation path. The electromagnetic waves radiated through the radiation path increase, and the radiation emission test cannot be passed. However, the return impedance Z of the return path in the circuit 1 of this embodiment does not continue to increase with the increase of frequency. According to the corresponding frequency, an appropriate resonant capacitor 40 can be selected to keep the return impedance Z of the return path within a low range in a high-frequency electromagnetic wave environment.

[0075] According to the calculation formula of the return impedance Z, the return impedance Z is kept within a small range, and the capacitance C of the resonant capacitor 40 can be calculated according to the frequency f, that is, the capacitance of the resonant capacitor 40 is related to the parasitic inductance of the spring 30 to form a resonant circuit.

[0076] Specifically, in an embodiment of the present invention, circuit 1 includes an integrated circuit 50 as an interference source in circuit 1. In this embodiment, integrated circuit 50 is only a concept provided for the convenience of describing the interference source, and does not only represent a specific circuit or circuit board, and integrated circuit 50 is not limited to being fixedly connected or electrically connected to circuit 1. In this embodiment, integrated circuit 50 can be an electronic component integrated on the same circuit board as ground terminal 10, or it can be other electronic components connected to or close to each other. Wherein, at the frequency of electromagnetic radiation of integrated circuit 50, resonant capacitor 40 resonates with parasitic inductance of shrapnel 30. In laser radar, integrated circuit 50 is usually able to radiate high-frequency electromagnetic waves outward to correspond to the actual application scenario of laser radar.

[0077] When the high-frequency electromagnetic wave generated by the integrated circuit 50 is a range value, for example, the circuit 1 includes a plurality of integrated circuits 50 that output electromagnetic waves of different frequencies, or the high-frequency electromagnetic wave output by the integrated circuit 50 will change during normal use. The frequency value with the largest radiation amount can be selected within the range of the electromagnetic wave frequency and substituted into the above calculation formula to calculate the capacitance value C of the resonant capacitor 40, so as to form a return path with the smallest return impedance Z for the electromagnetic wave with the largest radiation amount. Alternatively, the median value of the electromagnetic wave frequency range or the extreme values ​​at both ends of the range can be substituted into the above calculation formula, so that within the electromagnetic wave frequency range, the return impedance Z of the return path is kept within a smaller range, and both can pass the radiation emission test.

[0078] Specifically, taking the actual circuit design of LiDAR as an example, 1550MHz-1600MHz is used as the radiation emission test band. The following is a comparison based on the test results. Figure 1a The circuit shown in the embodiment according to the present invention Figure 2 The circuit shown in 1.

[0079] Figure 1c Shows Figure 1aThe radiation emission test results of the circuit shown in the figure, where the horizontal axis represents the frequency and the vertical axis represents the electromagnetic wave obtained through the radiation path. In the radiation emission test, the test results depend on the return impedance and radiation impedance. The radiation impedance is affected by many factors, which is difficult to calculate and not easy to quantitatively analyze. And at different frequencies, the radiation impedance will change. However, according to the above analysis, Figure 1a In the circuit shown, due to the influence of the parasitic inductance of the spring, the return impedance will increase significantly at high frequencies, affecting the radiation emission test results.

[0080] Depend on Figure 1c It can be seen that at frequencies of 1550MHz and 1600MHz, the radiation emission test results significantly exceeded the standard, that is, the amount of electromagnetic waves radiated outward from the radiation path is large, which may cause interference to other electronic products.

[0081] Figure 1d Shows Figure 1a The impedance of the spring (i.e., the return impedance) of the circuit shown in the figure changes with frequency. Figure 1e It can be seen that within the range of 1550MHz-1600MHz, the value of the parasitic inductance ACL of the spring changes little, so it can be regarded as a fixed value in the subsequent calculation process. The parasitic inductance value of the spring is regarded as 1.5137×10 -9 , at the frequencies of 1550MHz and 1600MHz, the impedance of the shrapnel is 14.7Ω and 15.2Ω respectively.

[0082] According to the embodiment of the present invention, the calculation formula of the return impedance Z is:

[0083]

[0084] The return impedance Z=0 is the smallest (ignoring the impedance generated at other locations in the return path, such as the impedance at the connection location). Substituting the return impedance Z=0 into the above formula, the calculation formula for the capacitance value C of the resonant capacitor 40 is obtained:

[0085]

[0086] Substituting the frequency f=1550MHz and the frequency f=1600MHz respectively, the capacitance values ​​C of the resonant capacitor 40 are calculated to be 6.9723pF and 6.5433pF respectively, that is, when the capacitance value C of the resonant capacitor 40 is 6.9723pF, at a frequency of 1550MHz, the return impedance is 0, and correspondingly, when the frequency is 1600MHz, the capacitance value C of the resonant capacitor 40 is optimally 6.5433pF. Considering that it is difficult to change the capacitance value of the resonant capacitor 40 at any time in practical applications, and the difference between the calculated optimal capacitance value C of the resonant capacitor 40 is small, which is acceptable in the practical application and radiation emission test of the laser radar, in the practical embodiment of the present invention, a fixed value between 6.5433pF-6.9723pF can be selected as the capacitance value C of the resonant capacitor 40.

[0087] In a specific embodiment of the present invention, the resonant capacitor 40 selects a capacitor product of standard specifications. Since the specifications of the capacitor are discontinuous, the resonant capacitor 40 in this embodiment selects a standard capacitor with a capacitance value C of 6.8 pF. The resonant capacitor 40 is connected in series with the spring 30 to form a return path. According to the above calculation formula, the return impedance Z of the return path is:

[0088]

[0089] When the frequency f is 1550MHz and 1600MHz, substitute into the above formula, see Figure 6 , the return impedance Z is 0.36Ω and 0.59Ω respectively, compared with Figure 1a In the circuit in which only the spring is provided, the return impedance in this embodiment is significantly reduced. Figure 5 As shown, the radiation emission test results of the circuit 1 in this embodiment at 1550 MHz and 1600 MHz are also significantly improved.

[0090] This embodiment uses a series resonant capacitor 40 and a spring 30 to form a low impedance connection between the ground terminal 10 and the circuit device 20. According to the above comparison, compared with Figure 1a As shown in the figure, the electrical connection is established by using the spring clip. The circuit 1 in this embodiment can significantly reduce the return impedance Z of the return path within the test frequency band of 1550MHz-1600MHz, thereby meeting the test requirements of radiated emission.

[0091] According to other embodiments of the present invention, the resonant capacitor 40 may also be a non-standard capacitor product, but the resonant capacitor 40 is formed in the circuit 1 so that its capacitance value is close to the capacitance value that can reduce the return impedance Z to the limit value, for example, a parallel plate capacitor is formed by processing a circuit board (see below). Figure 4 Detailed description).

[0092] According to the above two embodiments with different configurations of the resonant capacitor 40, Figure 3 and Figure 4 As shown below, combined Figure 3 and Figure 4 The arrangement form of the resonant capacitor 40 will be described.

[0093] Figure 3 The specific structure of the circuit 1 according to a preferred embodiment of the present invention is shown, wherein the resonant capacitor 40 can adopt a capacitor of standard specifications. In this embodiment, the circuit 1 also includes a circuit board 60, and the ground terminal 10 and the resonant capacitor 40 are arranged on the circuit board 60. For example, the ground terminal 10 and the resonant capacitor 40 are integrated on the circuit board 60, wherein the resonant capacitor 40 and the ground terminal 10 can be connected through a line, rather than directly arranging the resonant capacitor 40 above the ground terminal 10, which is conducive to improving the stability of the structure and preventing the resonant capacitor 40 from being directly squeezed by the spring 30 and damaged.

[0094] The resonant capacitor 40 in this embodiment is a capacitor of standard specifications, such as a chip ceramic capacitor, which can be welded and fixed on the circuit board 60, and connected to the ground terminal 10 and the spring 30 respectively. The spring 30 is configured to be connected to the circuit device 20, such as abutting against a metal structure, and the other end of the spring 30 can be connected to the circuit board 60, such as welding, and connected to the resonant capacitor 40 through the circuit on the circuit board 60. When the spring 30 is deformed, the elastic force of the spring 30 directly acts on the circuit board 60, and will not cause direct compression to the resonant capacitor 40. The deformation of the circuit board 60 can absorb part of the deformation of the spring 30 to maintain structural stability. In addition, the processing process of this embodiment is simple, and the circuit 1 can be obtained by automated processing, such as providing a circuit board 60 integrated with the ground terminal 10 and the resonant capacitor 40, and then processing the spring 30 by welding.

[0095] Figure 4 Another embodiment of the present invention is shown, in which the circuit 1 includes a circuit board 60, and the circuit board 60 has multiple layers, and an adjacent layer 61 of the ground terminal 10 is formed on the circuit board 60. In this embodiment, the spring 30 is soldered on the adjacent layer 61 through the pad 62, and the copper foil on the pad 62 and the adjacent layer 61 form a flat capacitor as a resonant capacitor 40. The resonant capacitor 40 in this embodiment can adjust the capacitance value C of the resonant capacitor 40 by adjusting parameters such as the facing area and / or the spacing, so that the return impedance Z of the return path tends to the minimum value, without being restricted by the standard specifications of the resonant capacitor. Specifically, a parasitic capacitor is formed between the copper foil where the pad 62 of the spring 30 is located and the adjacent ground terminal 10, as a resonant capacitor. The capacitance value C of the resonant capacitor in this embodiment is calculated as:

[0096]

[0097] Wherein, ε is the dielectric constant, which is the physical property of the filling material between adjacent layers 61 in the circuit board 60, S is the area of ​​the copper sheet where the pad 62 of the spring 30 is located, and d represents the interlayer spacing between the adjacent layer 61 and the ground terminal 10. ε and d can be fixed values ​​determined during the processing of the circuit board 60, and any desired parasitic capacitance can be obtained by adjusting the area S of the copper sheet where the pad 62 of the spring 30 is located. This embodiment can further improve the integration level of the circuit 1, and the spring 30 can be welded and fixed to the circuit board 60 through the pad 62, which can also improve the stability of the combination of the two, and a lower reflux impedance Z of the reflux path can be obtained.

[0098] According to a preferred embodiment of the present invention, the resonant capacitor 40 is connected in series between the spring 30 and the ground terminal 10. Usually, the ground terminal 10 is arranged on a circuit board. The resonant capacitor 40 is arranged between the spring 30 and the ground terminal 10 to reduce the difficulty and cost of processing. For example, the resonant capacitor 40 is directly welded to the ground terminal 10, and the spring 30 is welded on the resonant capacitor 40. Specifically, the circuit device 20 includes a metal structure, such as a shell of a laser radar, a packaging structure of a circuit, etc., wherein the metal structure is arranged relative to the ground terminal 10, and the spring 30 is arranged between the ground terminal 10 and the metal structure, and abuts against the metal structure. The structure of the spring 30 is arranged to be able to undergo elastic deformation within a certain range, and abutting against the metal structure can maintain electrical connection with the metal structure.

[0099] The circuit 1 in the above embodiment can be used Figure 7 The present invention also includes an embodiment of a laser radar 100, such as Figure 8 As shown, the laser radar 100 includes a circuit 1, wherein the circuit 1 includes a ground terminal, a circuit device, a spring and a resonant capacitor, wherein the spring and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal. Specifically, the circuit 1 is, for example, the circuit 1 in the aforementioned embodiment, wherein the circuit 1 is, for example, a circuit for realizing a core detection function in the laser radar 100. Preferably, the resonant capacitor in the circuit 1 is connected in series between the spring and the ground terminal to simplify the structural design and processing difficulty.

[0100] The laser radar 100 further includes a transmitting unit 110, a receiving unit 120 and a processing unit 130, wherein the transmitting unit 110 is configured to transmit a detection beam, and the detection beam is emitted from the laser radar 100. The receiving unit 120 is configured to receive an echo generated after the detection beam is reflected by an obstacle, and convert it into an electrical signal. The processing unit 130 can be integrated on the circuit 1, and is configured to obtain the position and / or reflectivity of the obstacle according to the electrical signal converted from the echo.

[0101] Furthermore, the transmitting unit 110 and the receiving unit 120 may also be integrated in the circuit 1 , and some components in the transmitting unit 110 and the receiving unit 120 may also be some interference sources that generate high-frequency electromagnetic waves in the circuit 1 .

[0102] The specific detection form of the laser radar 100 is not limited in this embodiment. Whether it is a mechanical rotating laser radar or a laser radar that uses a galvanometer, a rotating mirror, or other devices for scanning, the circuit 1 in the aforementioned embodiment can be used to improve the electromagnetic compatibility of the laser radar 100 and reduce the electromagnetic waves radiated to the outside by the laser radar 100.

[0103] According to a preferred embodiment of the present invention, the capacitance value of the resonant capacitor in circuit 1 is related to the parasitic inductance value of the spring to form a resonant circuit. Furthermore, the capacitance value of the resonant capacitor can be calculated by the calculation formula provided in the aforementioned embodiment, using the electromagnetic radiation frequency of the integrated circuit in the circuit and the parasitic inductance of the spring.

[0104] In a specific embodiment of the present invention, there are a variety of components with electromagnetic radiation inside the laser radar 100, and the frequency of the electromagnetic radiation will also be different in different working states of the laser radar. Therefore, in practical applications, the frequency of electromagnetic radiation is usually a range value. When calculating the capacitance value of the resonant capacitor using the range value of the electromagnetic radiation frequency, the maximum value of the frequency range value can be substituted into the above calculation formula, or the average value of the range value can be substituted into the above calculation formula, and the capacitance value of the resonant capacitor can be calculated in combination with the parasitic resistance of the shrapnel. In actual operation, the laser radar pays more attention to electromagnetic radiation in the high-frequency state. Therefore, preferably, the capacitance value of the resonant capacitor is calculated based on the maximum value of the frequency range value and the parasitic inductance of the shrapnel.

[0105] The present invention also includes an embodiment of a circuit design method S100 for a laser radar, such as Figure 8 As shown, the circuit includes a ground terminal, a circuit device, a spring and a resonant capacitor, and the spring and the resonant capacitor are connected in series between the ground terminal and the circuit device. Specifically, the circuit in this embodiment is, for example, circuit 1 in the aforementioned embodiment, and the specific design form and connection relationship of the spring and the resonant capacitor are no longer repeated.

[0106] like Figure 8As shown, in step S101, the frequency of the interference source of the circuit is obtained. In this embodiment, there is an interference source in the circuit, and the interference source generates electromagnetic waves at a fixed (or floating within a certain range) frequency, wherein the interference source can specifically be an electronic component in the circuit or other electronic components that are connected to or close to the circuit and can generate electromagnetic waves. In this step, the frequency of the interference source of the circuit is obtained for calculation in subsequent processes. When the frequency is a range value, such as the range of electromagnetic waves radiated by the interference source under normal motion, the frequency value with the largest radiation amount can be selected within the range of the electromagnetic wave frequency, or the median value of the electromagnetic wave frequency range or the extreme values ​​at both ends of the range.

[0107] In step S102, the parasitic inductance of the spring is obtained. Referring to the above description of the parasitic inductance of the spring, the parasitic inductance is a physical property of the spring, which is usually related to the structure and material of the spring, and has a small value change. When calculating the capacitance value of the resonant capacitor in this embodiment, it can be regarded as a fixed value. Specifically, the parasitic inductance of the spring can be directly obtained based on the physical characteristics of the standard part, or as described in the above embodiment, it can be obtained through three-dimensional electromagnetic field simulation software, such as Figure 1e shown.

[0108] The execution order between step S101 and step S102 is not limited in this embodiment, and they can be performed in any order or simultaneously. Preferably, when the accuracy needs to be improved, step S101 can be performed first, and a spring with a fixed parasitic inductance (or a negligible range) is selected according to the frequency of the interference source of the circuit.

[0109] In step S103, the capacitance value of the resonant capacitor is determined according to the frequency of the interference source and the parasitic inductance of the spring to reduce the impedance between the circuit device and the ground terminal at the frequency. According to a specific embodiment of the present invention, the capacitance value of the resonant capacitor can be calculated using the following formula:

[0110]

[0111] Wherein Z represents the return impedance, f represents the frequency of the circuit interference source, L represents the parasitic inductance of the shrapnel, and C represents the capacitance value of the resonant capacitor. In the above formula, the interference source frequency f and the parasitic inductance L of the shrapnel are both known values. Changing the capacitance value C of the resonant capacitor can change the return impedance Z. In this embodiment, an appropriate capacitance value C is selected to reduce the return impedance Z. Preferably, the return impedance Z with the minimum value is selected and substituted into the above formula. When the frequency f of the interference source is a range value, the median value of the frequency f can be substituted into the above formula for calculation, or the two extreme values ​​of the frequency f range can be substituted into the above formula to obtain the range of the capacitance value C of the resonant capacitor, and an appropriate resonant capacitor can be selected according to the range of the capacitance value C.

[0112] Furthermore, when processing a circuit designed using the design method in this embodiment, a resonant capacitor of a standard specification close to the capacitance value of the resonant capacitor can be selected according to the capacitance value of the resonant capacitor, such as a chip ceramic capacitor, to obtain the circuit; or a multi-layer circuit board can be used to weld the spring to the pad, and the copper sheet corresponding to the pad and the grounding end are separated by the filler between adjacent layers in the circuit board to form a flat capacitor as a resonant capacitor. The capacitance value C of the resonant capacitor is calculated as:

[0113]

[0114] Among them, ε is the dielectric constant, which is the physical property of the filling material between adjacent layers in the circuit board, S is the area of ​​the copper sheet where the spring pad is located, and d represents the layer spacing between the adjacent layers and the ground terminal. The dielectric constant ε and spacing d in the above formula can be obtained through the material and design of the circuit board, and are regarded as fixed values ​​in the calculation. After calculating the capacitance value C of the resonant capacitor, the above formula can be used to calculate the area S of the copper sheet where the spring pad is located, and processing can be carried out based on this.

[0115] Furthermore, in a preferred embodiment of the present invention, a resonant capacitor is connected in series between the spring and the ground terminal to facilitate processing.

[0116] like Fig. 9 As shown, the present invention also includes an embodiment of a method for manufacturing a circuit for a laser radar S200, wherein the circuit for the laser radar may be the circuit 1 in the aforementioned embodiment, and the circuit specifically includes a ground terminal. Fig. 9 The manufacturing method S200 will be described.

[0117] In step S201, a circuit device is provided. In this embodiment, the circuit device may be a metal structural component in the laser radar, such as a metal housing, a metal partition, etc. In this step, the specific shape and structure of the circuit device are obtained according to the actual design of the laser radar.

[0118] In step S202, a spring clip and a resonant capacitor are provided. Both the spring clip and the resonant capacitor can use standard specification accessories available in the market. For example, spring clips and resonant capacitors of appropriate sizes are selected according to the internal space size of the laser radar.

[0119] According to a preferred embodiment of the present invention, the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit. Further, the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the electromagnetic radiation frequency of the interference source in the circuit. Preferably, the capacitance value of the resonant capacitor can be calculated according to the calculation formula in the aforementioned embodiment, or a standard capacitor can be selected nearby based on the calculated capacitance value.

[0120] When the electromagnetic radiation frequency of the interference source in the circuit is a range value, the capacitance value of the resonant capacitor can be calculated based on the parasitic inductance of the spring and the maximum value or average value of the range value of the electromagnetic radiation frequency of the interference source.

[0121] In step S203, the spring clip and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal. The spring clip and the resonant capacitor can reduce the impedance between the circuit device and the ground terminal, form a return path, and make the impedance in the return path much smaller than the impedance of the radiation path, so that the electromagnetic radiation of the laser radar flows back to the ground terminal, reducing the electromagnetic waves radiated outward, and avoiding electromagnetic interference to other components or equipment.

[0122] In this embodiment, the spring and the resonant capacitor are connected in series, and the impedance of the return path can be kept within a small value even in a high-frequency electromagnetic radiation environment. For details, refer to the calculation formula and simulation results in the above-mentioned embodiment. The circuit obtained by the manufacturing method S200 in this embodiment is suitable for laser radar, so that the laser radar passes the radiation emission test and effectively reduces the amount of electromagnetic radiation emitted by the laser radar.

[0123] According to a preferred embodiment of the present invention, in step S203, a resonant capacitor is connected in series between the spring and the ground terminal, so as to simplify the manufacturing process and realize low-cost automated production.

[0124] Finally, it should be noted that the above description is only an embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A circuit for laser radar, comprising: Ground terminal; Circuit devices; Shrapnel and resonant capacitor, The spring and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal.

2. The circuit according to claim 1, wherein the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit. 3 . The circuit according to claim 1 , wherein the resonant capacitor is connected in series between the spring and the ground terminal.

4. The circuit according to claim 1, wherein the circuit device comprises a metal structure, the metal structure is arranged opposite to the ground end, and the spring is arranged between the ground end and the metal structure and abuts against the metal structure.

5. The circuit according to claim 1, further comprising a circuit board, wherein the ground terminal and the resonant capacitor are arranged on the circuit board, and the resonant capacitor is connected to the ground terminal and the spring respectively.

6. The circuit of claim 1, wherein the resonant capacitor comprises a chip ceramic capacitor.

7. The circuit according to claim 1 further includes a circuit board, on which there is an adjacent layer constituting the grounding terminal, wherein the spring is soldered to the adjacent layer via a soldering pad, and the resonant capacitor is formed between the copper foil where the soldering pad is located and the adjacent layer. 8 . The circuit according to claim 1 , further comprising an integrated circuit, wherein the resonant capacitor resonates with the parasitic inductance of the spring at a frequency of electromagnetic radiation of the integrated circuit.

9. A laser radar, comprising: A circuit for a laser radar, wherein the circuit comprises a ground terminal, a circuit device, a spring and a resonant capacitor, wherein the spring and the resonant capacitor are connected in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal; A transmitting unit, wherein the transmitting unit is configured to transmit a detection light beam; A receiving unit, wherein the receiving unit is configured to receive an echo generated after the detection light beam is reflected by an obstacle and convert the echo into an electrical signal; A processing unit is integrated on the circuit and configured to obtain the position and / or reflectivity of the obstacle according to the electrical signal of the echo. 10 . The laser radar according to claim 9 , wherein the capacitance value of the resonant capacitor is related to the parasitic inductance value of the shrapnel to form a resonant circuit.

11. The laser radar according to claim 9, wherein the resonant capacitor is connected in series between the spring and the ground terminal.

12. The laser radar according to claim 10, wherein the circuit further includes an integrated circuit, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the shrapnel and the electromagnetic radiation frequency of the integrated circuit.

13. The laser radar according to claim 12, wherein the electromagnetic radiation frequency of the integrated circuit is a range value, and the capacitance value of the resonant capacitor is calculated based on the maximum value or average value of the parasitic inductance of the shrapnel and the range value of the electromagnetic radiation frequency of the integrated circuit.

14. A design method for a circuit for a laser radar, the circuit comprising a ground terminal, a circuit device, a spring and a resonant capacitor, the spring and the resonant capacitor being connected in series between the ground terminal and the circuit device; the design method comprising: S101: Obtain the frequency of the interference source of the circuit; S102: Obtaining the parasitic inductance of the spring; and S103: Determine the capacitance value of the resonant capacitor according to the frequency of the interference source and the parasitic inductance of the spring to reduce the impedance between the circuit device and the ground terminal at the frequency. 15 . The design method according to claim 14 , wherein the resonant capacitor is connected in series between the spring and the ground terminal.

16. A method for manufacturing a circuit for a laser radar, the circuit comprising a ground terminal, the manufacturing method comprising: S201: providing circuit components; S202: provide springs and resonant capacitors; and S203: Connect the spring and the resonant capacitor in series between the ground terminal and the circuit device to electrically connect the circuit device to the ground terminal. 17 . The manufacturing method according to claim 16 , wherein the capacitance value of the resonant capacitor is related to the parasitic inductance value of the spring to form a resonant circuit.

18. The manufacturing method according to claim 16, wherein the step S203 comprises: The resonant capacitor is connected in series between the spring and the ground terminal.

19. The manufacturing method according to claim 17, wherein the circuit further comprises an integrated circuit, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the electromagnetic radiation frequency of the integrated circuit.

20. The manufacturing method according to claim 19, wherein the electromagnetic radiation frequency of the integrated circuit is a range value, and the capacitance value of the resonant capacitor is calculated based on the parasitic inductance of the spring and the maximum value or average value of the range value of the electromagnetic radiation frequency of the integrated circuit.

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