CN115436963A - Time difference of flight ranging module, anomaly detection method thereof and electronic equipment - Google Patents
Time difference of flight ranging module, anomaly detection method thereof and electronic equipment Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
- G01S17/06—Systems determining position data of a target
- G01S17/08—Systems determining position data of a target for measuring distance only
- G01S17/10—Systems determining position data of a target for measuring distance only using transmission of interrupted, pulse-modulated waves
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4811—Constructional features, e.g. arrangements of optical elements common to transmitter and receiver
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/497—Means for monitoring or calibrating
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0927—Systems for changing the beam intensity distribution, e.g. Gaussian to top-hat
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/09—Beam shaping, e.g. changing the cross-sectional area, not otherwise provided for
- G02B27/0938—Using specific optical elements
- G02B27/0944—Diffractive optical elements, e.g. gratings, holograms
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Abstract
The embodiment of the application provides a time of flight difference range module and abnormal detection method and electronic equipment thereof, and the time of flight difference range module includes: the driving chip is used for generating a driving signal; the point light source comprises a light emitter and a diffraction optical element, wherein the light emitter is used for emitting a light source signal according to a driving signal, the diffraction optical element is coated with an optical coating pattern to carry out light homogenizing treatment on the light source signal so as to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position; and the abnormity sensing circuit is used for sensing the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not, so that whether the diffraction optical element is abnormal or not is detected, and the corresponding processing of the time difference of flight ranging module can be carried out according to whether the dodging piece is abnormal or not.
Description
Technical Field
The embodiment of the application relates to the field of time difference of flight ranging, in particular to a time difference of flight ranging module, an abnormality detection method of the time difference of flight ranging module and electronic equipment.
Background
The Time of flight (TOF) module measures an object distance between a target object and a reference position by using an optical Time of flight.
For a point light source, the time difference of flight ranging module adopts a driving chip to drive a Vertical Cavity Surface Emitting Laser (VCSEL) to emit a light source signal, and the light source signal is subjected to light homogenizing treatment by a diffractive optical element to generate a modulation point light signal. The modulated spot light signal is used to determine the distance between the target object and the reference location.
In order to ensure a good ranging effect, the driving chip needs to generate a larger driving signal to drive the vertical cavity surface light emitter, so that the vertical cavity surface light emitter emits a sufficiently strong light source signal. Therefore, in the use process, once the diffraction optical element is abnormal, the time difference of flight ranging module cannot work normally.
Therefore, how to detect the abnormality of the diffractive optical element to ensure that the time difference of flight ranging module can perform corresponding processing according to whether the light homogenizing sheet has the abnormality becomes a technical problem to be solved urgently.
Disclosure of Invention
In view of this, embodiments of the present disclosure provide a time difference of flight ranging module, an anomaly detection method thereof, and an electronic device, which can detect an anomaly of a diffractive optical element and ensure normal operation of the time difference of flight ranging module.
The technical scheme provided by the embodiment of the application is as follows:
a time of flight difference range module, it includes:
the driving chip is used for generating a driving signal;
the point light source comprises a light emitter and a diffraction optical element, the light emitter is used for emitting a light source signal according to the driving signal, the diffraction optical element is coated with an optical coating pattern to carry out light homogenizing treatment on the light source signal so as to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position;
and the abnormity sensing circuit is used for sensing the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not.
Optionally, the abnormality sensing circuit is further configured to send the sensing signal to the driving chip, so that the driving chip stops generating the driving signal when the sensing signal is greater than a human eye safety threshold.
Optionally, the eye safety threshold value complies with the Class I standard of IEC 60825-1.
Optionally, the abnormality sensing circuit includes a resistance detection circuit for sensing a resistance of the optical coating pattern to generate the sensing signal.
Optionally, the resistance detection circuit comprises a current source electrically connected to the optical coating pattern to generate the sensing signal at a connection node of the optical coating pattern and the current source.
Optionally, the optical coating pattern is formed by bending a whole optical coating wire back and forth, one end of the optical coating wire is grounded, and the other end of the optical coating wire is electrically connected to the current source, so that the connection node is located between the other end and the current source to sense the resistance of the optical coating pattern, and a voltage signal corresponding to the resistance is generated at the connection node.
Optionally, the anomaly sensing circuit further includes a signal processing circuit, the signal processing circuit includes a filter circuit and a signal comparison circuit, the filter circuit is configured to perform filtering processing on the sensing signal, and the signal comparison circuit is configured to compare the sensing signal after filtering processing with the human eye safety threshold value to generate an anomaly monitoring signal for determining whether the diffractive optical element is anomalous.
Optionally, the signal comparison circuit has the real-time signal input, a reference signal input, and an output,
the reference signal input end is connected with a reference signal source, and the reference signal source corresponds to the human eye safety threshold;
the real-time signal input end is connected with the filter circuit and used for inputting the induction signal after filtering processing, and the induction signal is compared with the reference signal source to generate the abnormal monitoring signal;
the output end is used for outputting the abnormity monitoring signal.
Optionally, the filter circuit and the signal comparison circuit are built in the driving chip, and the current source and the reference signal source are generated by the driving chip.
Optionally, if the filtered sensing signal is greater than the eye-safe threshold value, so that the abnormal monitoring signal is inverted, it is determined that the diffractive optical element is abnormal.
Optionally, if the filtered sensing signal is smaller than the eye-safe threshold, the abnormal monitoring signal is at a low level, and if the filtered sensing signal is larger than the eye-safe threshold, the abnormal monitoring signal is inverted from the low level to a high level, and it is determined that the diffractive optical element is abnormal.
Optionally, the eye safety threshold is: and in the use stage or the mass production stage, measuring the value of the induction signal when the modulation point light signal of the time difference of flight ranging module is lower than or equal to the human eye safety standard.
A time difference of flight ranging method, comprising:
the driving chip generates a driving signal;
the light emitter of the point light source sends out a light source signal according to the driving signal, the diffraction optical element of the point light source carries out dodging processing on the light source signal to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position;
the abnormity sensing circuit senses the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not.
Optionally, the method further comprises: and stopping generating the driving signal when the induction signal is greater than the eye safety threshold value by the driving chip.
An electronic device comprises the time difference of flight ranging module of any one of the embodiments of the application.
According to the time difference of flight ranging module and the anomaly detection method and the electronic equipment thereof, the anomaly induction circuit is additionally arranged in the time difference of flight ranging module to induce the electrical property of the optical coating pattern so as to generate an induction signal, and whether the diffraction optical element is abnormal or not can be judged based on the induction signal. Therefore, whether the diffraction optical element is abnormal or not is detected by sensing the electrical property of the optical coating pattern, so that whether the time difference of flight ranging module is abnormal or not can be correspondingly processed according to the light homogenizing sheet.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments described in the embodiments of the present application, and other drawings can be obtained by those skilled in the art according to the drawings.
Fig. 1 is a schematic structural diagram of a time difference of flight ranging module according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a time difference of flight ranging module according to another embodiment of the present disclosure;
FIG. 3 is a schematic diagram illustrating the principle of sensing the abnormal sensing circuit according to an embodiment of the present disclosure;
fig. 4 is a schematic flowchart of an anomaly detection method for a time difference of flight ranging module according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings. For convenience of description, like reference numerals denote like parts in the embodiments of the present application, and a detailed description of the like parts is omitted in different embodiments for the sake of brevity. It should be understood that the thickness, length, width and other dimensions of the various components in the embodiments of the present application and the overall thickness, length, width and other dimensions of the integrated device shown in the drawings are only illustrative and should not constitute any limitation to the present application.
It should be noted that, without conflict, the embodiments and/or technical features in the embodiments described in the present application may be arbitrarily combined with each other, and the technical solutions obtained after the combination also should fall within the scope of the present application.
It should be understood that the specific examples in the embodiments of the present application are for the purpose of promoting a better understanding of the embodiments of the present application and are not intended to limit the scope of the embodiments of the present application.
It should also be understood that, in the various embodiments of the present application, the sequence numbers of the processes do not mean the execution sequence, and the execution sequence of the processes should be determined by the functions and the inherent logic of the processes, and should not constitute any limitation to the implementation process of the embodiments of the present application.
It is also to be understood that the terminology used in the embodiments of the present application and the appended claims is for the purpose of describing particular embodiments only, and is not intended to be limiting of the embodiments of the present application. For example, as used in the examples of this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.
As used herein, terms such as "first," "second," and "third" describe various components, elements, regions, layers, and/or sections, but such components, elements, regions, layers, and/or sections should not be limited by such terms. Such terms may only be used to distinguish one component, region, layer or section from another. Terms such as "first," "second," and "third" when used herein do not imply a sequence or order unless clearly indicated by the context.
Moreover, for ease of description, spatially relative terms such as "at 8230 \8230; below", "under", "at 8230 \8230; above", "upper" and the like may be used herein to describe the relationship of one component or member to another component or member illustrated in the figures. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
According to the time difference of flight ranging module, the abnormality detection method of the time difference of flight ranging module and the electronic device, the abnormality induction circuit is additionally arranged in the time difference of flight ranging module to induce the electrical property of the optical coating pattern to generate the induction signal, and whether the diffraction optical element is abnormal or not can be judged based on the induction signal. Therefore, the embodiment of the application realizes the detection of whether the diffraction optical element is abnormal or not by sensing the electrical property of the optical coating pattern so as to ensure that the time difference of flight ranging module can perform corresponding processing according to whether the uniform light sheet is abnormal or not.
The application provides an electronic equipment, its time of flight difference range module that includes any one of this application provides below. Specifically, the time difference of flight range module of this application embodiment can be installed in electronic equipment, and electronic equipment includes: any electronic device such as a portable terminal, an unmanned aerial vehicle, and a tablet computer, which is not limited in this embodiment of the present application.
Fig. 1 is a schematic structural diagram of a time difference of flight ranging module according to an embodiment of the present application; as shown in fig. 1, it includes: the driving chip 101, the point light source 102 (also called SPOT light source), and the abnormality sensing circuit 103, wherein the point light source 102 includes a light emitter 112 and a Diffractive Optical element 122, and an Optical coating pattern is coated on the Diffractive Optical element 122 (DOE). Wherein:
the driving chip 101 is used for generating a driving signal.
Specifically, in this embodiment, the driving chip 101 may specifically generate the driving signal according to an input signal, for example, specifically, an input current, and a product of the input current and the offset coefficient obtains the driving signal.
In this embodiment, the size of the input signal is determined according to an application scenario. Further, the input signal and the driving signal may both be current signals. It should be understood that the input signal and the driving signal are only illustrated here by way of example, and the input signal and the driving signal are not limited to only current signals.
The optical transmitter 112 is used for emitting a light source signal according to the driving signal.
The diffractive optical element 122 is coated with an optical coating pattern to homogenize the light source signal to generate a modulated spot light signal, which is used to determine the distance between the target and the reference position.
Specifically, the modulated point optical signal irradiates the target object and is reflected to form a reflected optical signal, so that the time difference of flight ranging module determines the distance between the target object and the reference position according to the time difference of flight of the reflected optical signal and the modulated point optical signal.
In this embodiment, the optical transmitter 112 is, for example, a vertical cavity surface optical transmitter VCSEL. Here, it should be noted that the vertical cavity surface optical transmitter VCSEL is only an example of an optical transmitter and is not limited thereto. One of ordinary skill in the art may use other types of light emitters 112 as required by the application, as long as the distance between the target object and the reference position can be determined.
The anomaly sensing circuit 103 is used for sensing the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffractive optical element 122 is anomalous. The electrical property includes any property that can reflect a change in the pattern of the optical coating film due to an abnormality of the diffractive optical element 122.
In particular, anomalies of the diffractive optical element 122 may include, but are not limited to: breakage or falling off.
In this embodiment, the abnormality sensing circuit 103 may be disposed at a position where it can sense the electrical property of the optical coating pattern to generate a sensing signal, as long as it can detect an abnormality of the diffractive optical element 122.
In this embodiment, for the time difference of flight ranging module using the point light source 102, since the diffractive optical element 122 is coated with the optical coating pattern, when the diffractive optical element 122 is abnormal, such as being damaged or falling off, the optical coating pattern may break or fall off, so that the optical coating pattern is opened, and the electrical property of the optical coating pattern may be changed due to the open circuit. For this reason, based on the scheme provided in the embodiment of fig. 1 described above, the electrical property of the optical coating pattern can be sensed by the anomaly sensing circuit 103 to generate a sensing signal, and whether the diffractive optical element 122 is anomalous can be determined based on the sensing signal.
Fig. 2 is a schematic structural diagram of a time difference of flight ranging module according to another embodiment of the present disclosure; as shown in fig. 2, in the present embodiment, in addition to the driving chip 101, the point light source 102, and the abnormal sensing circuit 103 shown in fig. 1, the difference is that the abnormal sensing circuit 103 is further configured to send a sensing signal to the driving chip, so that the driving chip stops generating the driving signal when the sensing signal is greater than the eye-safe threshold.
In the embodiment shown in fig. 2, for example, when the sensing signal is greater than the eye safety threshold, the driving chip stops generating the driving signal, so that it is avoided that the driving chip continues to generate the driving signal, which causes the generated modulated spot light signal to have more concentrated light energy, thereby endangering the eye safety.
In fig. 2, the eye safety threshold is: and in the use stage or the mass production stage, the value of the sensing signal when the modulation point optical signal of the time difference of flight distance measurement module is lower than or equal to the human eye safety standard is measured. The eye safety threshold value can be stored in the drive chip or the main control chip.
Specifically, the reflectivity of the diffractive optical element 122, the intensity of the light source signal, the type of the abnormality sensing circuit 103, and the relative position of the abnormality sensing circuit 103 and the light emitter 112 may affect the magnitude of the sensing signal. Therefore, by measuring the eye-safe threshold value during the use phase, the eye-safe threshold value is made more accurate.
Specifically, for the situation that the eye safety threshold is determined in the stage of mass production, the value of the sensing signal when the modulation point light signal is lower than or equal to the eye safety standard can be stored in the driving chip to be directly used as the eye safety threshold, so that the eye safety threshold can be directly used in the stage of using the time difference of flight ranging module, the eye safety threshold does not need to be measured in use, and the eye safety threshold is simpler to obtain.
Specifically, the human eye safety standard in the embodiment of the present application may adopt a Class I standard of IEC 60825-1.
In practical use, in order to further improve the eye safety, the value of the sensing signal when the modulated spot light signal is lower than the eye safety standard is generally set as the eye safety threshold.
FIG. 3 is a schematic diagram illustrating the principle of sensing the abnormal sensing circuit according to an embodiment of the present disclosure; as shown in fig. 3, the abnormality sensing circuit 103 includes a resistance detection circuit 113 and a signal processing circuit 123, and the resistance detection circuit 113 and the signal processing circuit 123 are electrically connected. The signal processing circuit 123 includes a filter circuit 1231 and a signal comparison circuit 1232. The filter circuit 1231 is electrically connected to the signal comparator circuit 1232.
The resistance detection circuit 113 is used for sensing the resistance of the optical coating pattern R _ ITO to generate a sensing signal Vin. The filter circuit 1231 is configured to perform filtering processing on the sensing signal. The signal comparison circuit 1232 is configured to compare the filtered sensing signal with a human eye safety threshold to generate an abnormality monitoring signal for determining whether the diffractive optical element 122 is abnormal.
Referring to fig. 3, as mentioned above, when the diffractive optical element 122 is abnormal, the optical coating pattern is disconnected, resulting in an open circuit of the optical coating pattern, which corresponds to a large resistance of the optical coating pattern exceeding the resistance of the optical coating pattern when the diffractive optical element 122 is normal. Therefore, before and after the abnormality of the diffractive optical element 122, the change in the resistance value of the optical coating pattern is reflected on the sensing signal after the filtering process. Therefore, the induction signal after filtering processing is compared with the human eye safety threshold value to generate an abnormal monitoring signal capable of reflecting whether the diffractive optical element 122 is abnormal, so that whether the diffractive optical element 122 is abnormal can be accurately judged based on the abnormal monitoring signal.
In this embodiment, the resistance detection circuit 113 includes a current source LDR _ IDAC _ SEL electrically connected to the optical plating pattern to generate a sense signal at a connection node of the optical plating pattern and the current source. Under the action of a current signal provided by the current source, when the electrical property of the optical coating pattern, such as resistance, changes, a stable sensing signal can be generated at the connection node, so that the accuracy of abnormality detection is improved.
It should be noted that the resistance detection circuit 113 including a current source electrically connected to the optical coating pattern is merely an example, and is not limited thereto, and a person skilled in the art may use other circuit structures in other embodiments as long as the sensing of the electrical property of the optical coating pattern can be achieved.
Specifically, one end of the optical coating pattern is grounded, and the other end is electrically connected with the current source LDR _ IDAC _ SEL, so that a connection node is located between the other end and the current source to sense the resistance of the optical coating pattern and generate a voltage signal corresponding to the resistance at the connection node. Accordingly, the voltage signal can be directly used as the sensing signal Vin, so that the stability of the signal is ensured, the accuracy of the anomaly detection is improved, and the structure of the anomaly sensing circuit 103 is relatively simple.
Specifically, the optical coating pattern is formed by bending an entire optical coating wire back and forth, for example.
Here, it should be noted that, in other embodiments, if the optical coating pattern is formed in other manners, the anomaly sensing circuit 103 may be another structure that realizes sensing of the electrical property of the optical coating pattern, and the electrical property is not limited to be a resistor.
Optionally, the filter circuit 1231 and the signal comparison circuit 1232 are built in the driving chip 101, so that the circuit design is simplified, and the compactness of the circuit structure is ensured.
Specifically, the filter circuit 1231 includes a filter resistor R and a filter capacitor C, where the filter resistor is connected between the real-time signal input end and the connection node to perform dc filtering on the sensing signal; one end of the filter capacitor is grounded, and the other end of the filter capacitor is connected between the real-time signal input end and the connection node so as to perform alternating current filtering on the induction signal.
In this embodiment, the signal comparison circuit 1232 has a real-time signal input terminal, a reference signal input terminal, and an output terminal, where the reference signal input terminal is connected to the reference signal source Vbg and serves as a safety threshold for human eyes; the real-time signal input end is connected with the filter circuit 1231 and is used for inputting the induction signal after filtering processing, and the induction signal is compared with the reference signal source to generate an abnormal monitoring signal; the output end is used for outputting an abnormal monitoring signal AD _ TMR _ COMP _ OUT.
The current source and the reference signal source are generated by the driving chip 101, thereby simplifying the circuit design while ensuring the compactness of the circuit in structure.
In this embodiment, as described above, the filtered sensing signal is compared with the eye safety threshold by the signal comparison circuit 1232, and when the filtered sensing signal is greater than the eye safety threshold and the abnormality monitoring signal is inverted, it is determined that the diffractive optical element 122 is abnormal.
Further, as mentioned above, when the diffractive optical element 122 is abnormal, the optical coating pattern is disconnected, and the optical coating pattern is equivalent to an open circuit, i.e., the resistance is large, exceeding the resistance of the optical coating pattern when the diffractive optical element 122 is normal. Therefore, when the diffractive optical element 122 is normal, the filtered sensing signal is smaller than the eye-safe threshold, and correspondingly, the abnormal monitoring signal is at a low level. If the induction signal after the filtering processing is larger than the human eye safety threshold, correspondingly, the abnormal monitoring signal is inverted from a low level to a high level, and therefore, it is determined that the diffractive optical element 122 is abnormal.
Here, in the present embodiment, the abnormality monitoring signal is described as being inverted from a low level to a high level by way of example, and is not limited to this. In fact, it is obvious to those skilled in the art that the inversion from the low level to the high level of the anomaly monitoring signal is only one implementation of the inversion, and in other embodiments, the anomaly sensing circuit 103 is modified on the premise that the anomaly detection of the diffractive optical element 122 can be implemented, so that the inversion of the anomaly monitoring signal can also be the high level and the low level.
Of course, if the eye safety threshold is not determined in the mass production stage, the eye safety threshold may also be determined according to the requirements of the application scenario in the use process of the time difference of flight ranging module and stored in the driver chip (such as EPROM).
Fig. 4 is a schematic flowchart of an anomaly detection method for a time difference of flight ranging module according to an embodiment of the present application; as shown in fig. 4, it includes:
s401, the driving chip generates a driving signal;
s402, a light emitter included in the point light source emits a light source signal according to a driving signal, a diffraction optical element included in the point light source carries out dodging processing on the light source signal to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position;
s403, the abnormity sensing circuit senses the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not.
Further, in other embodiments, the method for detecting an anomaly of the time difference of flight ranging module may further include: and stopping generating the driving signal when the sensing signal of the driving chip is greater than the human eye safety threshold value. This step may be specifically performed after the determination of the abnormality of the diffractive optical element.
It should be noted that, according to implementation needs, each component/step described in the embodiment of the present application may be divided into more components/steps, and two or more components/steps or partial operations of the components/steps may also be combined into a new component/step to achieve the purpose of the embodiment of the present application.
The above embodiments are only used for illustrating the embodiments of the present application, and not for limiting the embodiments of the present application, and those skilled in the relevant art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present application, so that all equivalent technical solutions also belong to the scope of the embodiments of the present application, and the scope of patent protection of the embodiments of the present application should be defined by the claims.
Claims (15)
1. The utility model provides a time difference of flight range unit, its characterized in that includes:
the driving chip is used for generating a driving signal;
the point light source comprises a light emitter and a diffraction optical element, the light emitter is used for emitting a light source signal according to the driving signal, the diffraction optical element is coated with an optical coating pattern so as to carry out uniform light processing on the light source signal to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position;
and the abnormity sensing circuit is used for sensing the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not.
2. The time difference of flight ranging module of claim 1, wherein the anomaly sensing circuit is further configured to send the sensing signal to the driver chip, and the driver chip stops generating the driving signal when the sensing signal is greater than a human eye safety threshold.
3. The time difference of flight ranging module of claim 2, wherein the eye-safe threshold value complies with the ClassI standard of IEC 60825-1.
4. The time difference of flight ranging module of claim 2, wherein the anomaly sensing circuit comprises a resistance detection circuit for sensing a resistance of the optical coating pattern to generate the sensing signal.
5. The time difference of flight ranging module of claim 4, wherein the resistance detection circuit comprises a current source electrically connected to the optical coating pattern to generate the sensing signal at a connection node of the optical coating pattern and the current source.
6. The time difference of flight ranging module of claim 5, wherein the optical coating pattern is formed by bending a whole optical coating wire back and forth, one end of the optical coating wire is grounded, and the other end of the optical coating wire is electrically connected with the current source, so that the connection node is located between the other end and the current source to sense the resistance of the optical coating pattern, and a voltage signal corresponding to the resistance is generated at the connection node.
7. The time difference of flight ranging module of claim 6, wherein the anomaly sensing circuit further comprises a signal processing circuit, the signal processing circuit comprises a filter circuit and a signal comparison circuit, the filter circuit is configured to filter the sensing signal, and the signal comparison circuit is configured to compare the filtered sensing signal with the eye safety threshold to generate an anomaly monitoring signal for determining whether the diffractive optical element is anomalous.
8. The time difference of flight ranging module of claim 7, wherein the signal comparison circuit has the real-time signal input, a reference signal input, and an output,
the reference signal input end is connected with a reference signal source, and the reference signal source corresponds to the human eye safety threshold;
the real-time signal input end is connected with the filter circuit and used for inputting the induction signal after filtering processing, and the induction signal is compared with the reference signal source to generate the abnormal monitoring signal;
the output end is used for outputting the abnormity monitoring signal.
9. The time difference of flight ranging module of claim 8, wherein the filter circuit and the signal comparison circuit are built in the driver chip, and the current source and the reference signal source are generated by the driver chip.
10. The time difference of flight ranging module of claim 9, wherein if the filtered sensing signal is greater than the eye-safe threshold value, such that the anomaly monitoring signal is inverted, it is determined that the diffractive optical element is anomalous.
11. The time difference of flight ranging module of claim 10, wherein if the filtered sensing signal is smaller than the eye-safe threshold, the abnormal monitoring signal is at a low level, and if the filtered sensing signal is larger than the eye-safe threshold, the abnormal monitoring signal is inverted from the low level to a high level, and it is determined that the diffractive optical element is abnormal.
12. The jet-lag ranging module of claim 11, wherein the eye-safe thresholds are: and in the use stage or the mass production stage, measuring the value of the induction signal when the modulation point optical signal of the time difference of flight ranging module is lower than or equal to the human eye safety standard.
13. A time difference of flight ranging method, comprising:
the driving chip generates a driving signal;
the light emitter of the point light source sends out a light source signal according to the driving signal, the diffraction optical element of the point light source carries out dodging processing on the light source signal to generate a modulation point light signal, and the modulation point light signal is used for determining the distance between a target object and a reference position;
the abnormity sensing circuit senses the electrical property of the optical coating pattern to generate a sensing signal, and the sensing signal is used for judging whether the diffraction optical element is abnormal or not.
14. The method of claim 13, further comprising: and when the induction signal is greater than the eye safety threshold value, the driving chip stops generating the driving signal.
15. An electronic device comprising the time of flight difference ranging module of any one of claims 1-12.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113050067A (en) * | 2021-02-26 | 2021-06-29 | 嘉兴驭光光电科技有限公司 | Laser projection module |
| CN213843575U (en) * | 2020-05-27 | 2021-07-30 | 杭州驭光光电科技有限公司 | Diffractive optical element, zoned uniform light projection system, and electronic apparatus |
| CN213986816U (en) * | 2020-12-09 | 2021-08-17 | 江西欧迈斯微电子有限公司 | Light projection system, laser sensing module and electronic equipment |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN213843575U (en) * | 2020-05-27 | 2021-07-30 | 杭州驭光光电科技有限公司 | Diffractive optical element, zoned uniform light projection system, and electronic apparatus |
| CN213986816U (en) * | 2020-12-09 | 2021-08-17 | 江西欧迈斯微电子有限公司 | Light projection system, laser sensing module and electronic equipment |
| CN113050067A (en) * | 2021-02-26 | 2021-06-29 | 嘉兴驭光光电科技有限公司 | Laser projection module |
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