CN108606774B - Automatic safety protection device and method suitable for ophthalmic optical scanning imaging device - Google Patents
Automatic safety protection device and method suitable for ophthalmic optical scanning imaging device Download PDFInfo
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Abstract
The invention discloses an automatic safety protection device and method suitable for an ophthalmic optical scanning imaging device, which enable the optical power of the optical scanning imaging device to be within the safety range of human eyes, and if the detected light source power exceeds the preset safety standard or the scanning speed is smaller than the preset safety standard, the light source is turned off, the scanning point is moved out of the visual field of the optical scanning imaging device, and the safety of ophthalmic medical treatment is ensured through a photoelectric element, an analog-digital circuit and a logic circuit.
Description
Technical Field
The invention relates to the technical field of safety protection, in particular to an automatic safety protection device and method suitable for an ophthalmic optical scanning imaging device.
Background
There are a variety of optical scanning imaging devices currently used in ophthalmic diagnostics, such as: optical coherence tomography imaging (Optical Coherence Tomography, OCT), confocal scanning laser ophthalmoscope (Confocal Scanning Laser Ophthalmoscope, cSLO), line scanning laser ophthalmoscope (Line Scan Ophthalmoscope, LSO). The optical scanning imaging devices are used for non-invasive rapid imaging of biological tissues such as human eyes, have the advantages of high resolution, high sensitivity, high precision, low damage to tissues and the like, and are widely applied to the field of ophthalmic diagnosis and treatment.
The eyes are important information sensing organs of human beings, receive external information through light rays and form images in the brain, so that our actions are commanded. The retina is an important component of the optical system of the human eye, and its function is equivalent to a photoelectric conversion device, and an optical signal is converted by the retina into a bioelectric signal that can be recognized by the brain. Various types of cells are distributed on the retina and play a very important role in human vision. At the same time, these cells are also affected by a variety of pathological factors, resulting in the development of a variety of serious blinding diseases such as diabetic retinopathy, glaucoma, macular degeneration, and retinitis pigmentosa.
Several technical approaches to optical scanning imaging devices mentioned above are now widely used in ophthalmic clinical practice. Both of these techniques use infrared or near infrared light sources and non-invasive detection methods, with significantly less risk of damage to the human eye than with visible light sources and traditional invasive detection methods. National and international laser safety standards (gb_7247-1-2012,ANSI Z136.1 2007 and IEC 60825-1 2011) have strict regulations on various light sources and long-term radiated safety laser power. Although the wavelength of infrared or near infrared light is long and there is no chemical damage to tissues, once the power irradiated to human eyes exceeds the safe power, permanent thermal effect damage to human eyes is likely to occur, and when the power is too high, the damage is likely to be irreversible damage, so that the damage is very important for monitoring optical power.
In addition, according to the aforementioned safety standards, diffuse light is less harmful to the human eye than point light sources at equal power. OCT and cSLO are both point-scan based techniques, where the light source is focused on the target and the scanning is fast. The safety threshold for this illumination mode is lower than diffuse reflection but higher than a stationary point source. For example, according to the FDA registration report by Zeiss Elite 9000, the safety threshold of the 1050nm point scanning light source is set at 5.4mw, and the safety threshold of the 1050nm point light source is 1.9mw in the aforementioned safety standard. In practical systems, the detected light power of OCT and cSLO may be set below the safety threshold of a specially evaluated line or diffuse light source, but may be above the safety threshold of a stationary point light source. Because of the rapid movement of the spot, its thermal effect on the retina is more similar to a linear light source or diffuse light, still complete for the human eye. However, if the spot stops, there is a possibility that injury to the human eye is caused. Thus, in addition to safeguarding the power of the light source, it is also necessary to monitor the position and speed of the scanning device without interruption, and if the speed is below a certain threshold and the scanning light is on the retina, the light source will be immediately turned off.
Disclosure of Invention
The invention aims to solve the technical problem of providing an automatic safety protection device and an automatic safety protection method which are suitable for an ophthalmic optical scanning imaging device, and can ensure the safety of ophthalmic medical treatment through a photoelectric element, an analog digital circuit and a logic circuit.
In order to solve the above technical problems, the present invention provides an automatic safety device suitable for an ophthalmic optical scanning imaging device, comprising: the system comprises a light source control module, a light source, a TAPD, a power monitoring module, a scanning galvanometer drive, a speed monitoring module, a threshold setting module, a threshold reading back module, a threshold control module, a position monitoring module and a logic judging module; the light source control module receives signals fed back by the logic judging module, controls the light source to be turned on or turned off, outputs light beams by the light source for ophthalmic medical diagnosis and treatment, the TAPD divides the light beams emitted by the light source into two light beams according to different proportions, and the power monitoring module outputs a comparison result by the TAPD for the logic judging module to use; the scanning galvanometer controls the light beam to scan in a two-dimensional space, the scanning galvanometer drive controls the angle change of the galvanometer through a direct current signal, the speed monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, a digital signal of a comparison result is output for the logic judging module to use, the position monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, and a digital signal of the comparison result is output for the logic judging module to use; the threshold control module realizes closed loop setting of threshold voltage, the threshold setting module realizes setting of threshold voltage by the digital-to-analog conversion chip, and the threshold readback module realizes readback of threshold voltage by the analog-to-digital conversion chip.
Preferably, the TAPD integrates a light detector, and the light beam emitted by the light source is divided into two light beams according to different proportions, one light beam is used for power monitoring and the other light beam is used for diagnosis and treatment light paths.
Preferably, the power monitoring module specifically comprises: the power monitoring signal output by TAPD is input into the power monitoring module by P23, is subjected to low-pass filtering by U52A and U52B after passing through a transimpedance amplifier U4, and is subjected to threshold comparison by a comparator U5.
Preferably, the speed monitoring module specifically comprises: the position signals of the two vibrating mirrors are respectively input into a differential circuit formed by U28A and U28B and converted into speed signals; then the absolute value circuit formed by U27 and U30 is passed through, then U29A is added, then the absolute value circuit formed by U29B is passed through, and then the threshold value comparison is made by comparator U26.
Preferably, the threshold readback module specifically includes: after the two paths of threshold values pass through the U3C buffer operation amplifier and the U3D buffer operation amplifier respectively, a multichannel analog-to-digital conversion chip U8 completes the readback function of the threshold values.
Preferably, the position monitoring module specifically includes: the position signals of the two vibrating mirrors are respectively input into an absolute value circuit formed by U46 and U48, and then are respectively converted into digital signals by a comparator U47 and a comparator U49, and are output to a logic judging module for judging whether scanning is in a field of view.
Preferably, the integrated rate of motion v of the vibrating mirror must be greater than the minimum speed v required by safety standards M I.e. v.gtoreq.v M Whereinv x And v y The rates of the x-vibrating mirror and the y-vibrating mirror are respectively; />Can ensure v M As long as the monitoring circuit ensures that the sum of the absolute values of the speeds of the two scanning axes is greater than the safe minimum speed>The scanning speed is ensured to be larger than the threshold value by times, and the requirement on the safety monitoring of the scanning speed is met.
Correspondingly, the automatic safety protection method suitable for the ophthalmic optical scanning imaging device comprises the following steps of:
(1) Starting up to set threshold values of power monitoring and speed monitoring respectively, if the difference between the readback threshold value and the set threshold value is within an allowable range, turning on a scanning vibrating mirror and resetting a speed monitoring module to start monitoring, otherwise, turning off a light source and giving a safety warning;
(2) After the speed monitoring is started, if the speed is greater than a set threshold value or the position of the vibrating mirror is greater than the set threshold value, the light source can be turned on at the moment, and otherwise, the light source is turned off and a safety warning is given;
(3) After the light source is turned on, the power monitoring module is reset to start monitoring, the module can automatically judge whether the light beam power is smaller than a safety power threshold value, if so, the normal operation mode is entered, otherwise, the light source is turned off and a safety warning is given;
(4) After entering a normal operation mode, the speed monitoring module, the power monitoring module and the position monitoring module can simultaneously start automatic monitoring in parallel, the following two conditions occur, the logic judging module can automatically turn off the light source and give out safety warning, the scanning position is in the scanning view field, and the scanning speed is smaller than or equal to the speed threshold value or the beam power is larger than or equal to the safety power threshold value.
The beneficial effects of the invention are as follows: the invention realizes triple monitoring of the power, scanning speed and scanning position of the light source, switches off the light source output and moves the scanning point out of the scanning visual field when logic judgment detects that the scanning point does not meet the preset condition of the safety standard, realizes automatic safety protection of human eyes in the optical scanning imaging process, greatly increases the safety guarantee of the ophthalmic optical scanning imaging device, and ensures the safety of ophthalmic medical treatment through the photoelectric element, the analog digital circuit and the logic circuit.
Drawings
Fig. 1 is a schematic view of the structure of the device of the present invention.
Fig. 2 is a schematic diagram of a power monitoring module according to the present invention.
Fig. 3 is a schematic diagram of a speed monitoring module according to the present invention.
Fig. 4 is a schematic structural diagram of a position monitoring module according to the present invention.
FIG. 5 is a schematic flow chart of the method of the present invention.
Fig. 6 is a schematic circuit diagram of a power monitoring module according to the present invention.
Fig. 7 is a schematic circuit diagram of a speed monitoring module according to the present invention.
Fig. 8 is a schematic circuit diagram of a threshold setting module according to the present invention.
FIG. 9 is a schematic diagram of a threshold readback module circuit according to this invention.
Fig. 10 is a schematic circuit diagram of a position monitoring module according to the present invention.
Detailed Description
As shown in fig. 1, an automatic safety shield apparatus for an ophthalmic optical scanning imaging device, comprising: the system comprises a source control module, a light source, a TAPD, a power monitoring module, a scanning galvanometer drive, a speed monitoring module, a threshold setting module, a threshold reading back module, a threshold control module, a position monitoring module and a logic judging module; the light source control module receives signals fed back by the logic judging module, controls the light source to be turned on or turned off, outputs light beams by the light source for ophthalmic medical diagnosis and treatment, the TAPD divides the light beams emitted by the light source into two light beams according to different proportions, and the power monitoring module outputs a comparison result by the TAPD for the logic judging module to use; the scanning galvanometer controls the light beam to scan in a two-dimensional space, the scanning galvanometer drive controls the angle change of the galvanometer through a direct current signal, the speed monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, a digital signal of a comparison result is output for the logic judging module to use, the position monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, and a digital signal of the comparison result is output for the logic judging module to use; the threshold control module realizes closed loop setting of threshold voltage, the threshold setting module realizes setting of threshold voltage by the digital-to-analog conversion chip, and the threshold readback module realizes readback of threshold voltage by the analog-to-digital conversion chip.
A light source control module: and receiving a signal fed back by the logic judgment module circuit to control the on or off of the light source.
Light source: the output beam is used for ophthalmic medical treatment and the power of the treatment beam must meet the eye safety level.
TAPD: TAPD (Integrated Tap Photodiode) is a fiber optic beam splitter incorporating a photodetector. The light beam emitted by the light source can be divided into two beams according to different proportions, one beam is used for power monitoring and the other beam is used for diagnosis and treatment light paths. The properties of the two light beams after beam splitting are identical to those of the light source. The response wavelength is in the light source emission wavelength range and is used for measuring the power of the power monitoring light beam so as to deduce whether the power of the diagnosis and treatment light path light beam is in the safe power range or not, and the result is fed back to the logic judging circuit module.
And a power monitoring module: as shown in fig. 2, the current signal related to the power of the power monitoring beam output by the TAPD is converted into a voltage signal via TIA (Transimpedance Amplifier ) and low-pass filtered, and compared with the power threshold voltage set by the threshold setting module by the comparator, and the digital signal of the comparison result is output for the logic judging module.
Scanning galvanometer: two galvanometers are usually used as a group, and the light beam is controlled to scan in a two-dimensional space so as to achieve the purpose of scanning and imaging.
Scanning galvanometer driving: the angle change of the scanning galvanometer is controlled by a direct current signal. The scanning speed and the repeated positioning accuracy of the scanning galvanometer system are ensured by the servo motor and the position sensor and the design thought of a negative feedback loop.
And the speed monitoring module is used for: in practical use, the x-galvanometer and the y-galvanometer may have large differences in velocity, even if one galvanometer remains stationary while the other galvanometer scans at high speed. The purpose of the speed monitoring is that the integrated movement speed v of the vibrating mirror must be greater than the minimum speed v required by the safety standard M I.e. v.gtoreq.v M Whereinv x And v y The rates of x-galvanometer and y-galvanometer, respectively. The integrated motion velocity v of the vibrating mirror can be digitized v x And v y And then on a microprocessor or FPGA. For the safety circuit, preferably, a pure analog circuit method is adopted, and the circuit is striven for the simplest to ensure the highest reliability so as to monitor the comprehensive movement rate of the vibrating mirror.
In analog circuits, the signal square or root number is not easily obtained directly. In this embodiment, we use the following method: as shown in fig. 3, the position signal of the galvanometer fed back by the scanning galvanometer drive is converted into a speed signal by a differential circuit, the superposition of the speeds of the two galvanometers is realized by an addition circuit, the speed signal is input into a comparator after low-pass filtering, the speed signal is compared with the speed threshold voltage set by a threshold setting module by the comparator, and a digital signal of the comparison result is output for a logic judging module. The logic to do this is as follows:
easily proved by onlyCan ensure that v is greater than or equal to v M . That is, as long as the monitoring circuit ensures that the sum of the absolute values of the two scan axis minute speeds is greater than the safe minimum speed +.>The scanning speed is ensured to be larger than the threshold value by times, and the requirement on the safety monitoring of the scanning speed can be met. The proving process is as follows:
assuming secure circuit assurance
The inequality is positive real on both sides, so
(|v x |+|v y |) 2 ≥2v M 2 (2)
Because of
(|v x |-|v y |) 2 ≥0 (3)
2|v x | 2 +2|v y | 2 -(|v x |+|v y |) 2 ≥0 (4)
So that
(|v x |+|v y |) 2 ≤2|v x | 2 +2|v y | 2 (5)
Combining consideration inequality (2) can be derived
2|v x | 2 +2|v y | 2 ≥2v M 2 (6)
So that
v 2 ＝|v x | 2 +|v y | 2 ≥v M 2
|v|≥v M (7)
Thus, it proves that only the requirements ofI.e. the sum of the absolute values of the two scanning axis component speeds is greater than the threshold value +.>The total scanning speed is ensured to be larger than the threshold value by times, thereby meeting the requirement of speed monitoring.
In this embodiment, the circuit monitors |v in real time x I and V y Sum of I and set a thresholdWhen |v x |+|v y |≥v T Can ensure that |v| is not less than v M 。
But should be noted that ifAlthough |v|v M It is still possible to trigger the safety protection circuit. In the safety circuit, this part can be regarded as system redundancy and is not a problem. If->Then->The safety circuit is not triggered.
In practice, due to the presence of noise and environmental disturbances, more redundancy is required to avoid the effects of noise and environmental disturbances. For example, the speed safety threshold in the circuit may be set to v T ＝2v M . When |v x |+|v y |≥v T Can ensureIf |v| is not less than 2v M Then |v x |+|v y |≥2v M The safety circuit is not triggered.
When the control program of the vibrating mirror needs to ensure that the scanning light source is started, the speed of the vibrating mirror is always greater than 2v M So as not to trigger the safety circuit. The control program generally requires furtherRedundancy is maintained, e.g. the speed of the galvanometer is always greater than 3v when the scanning light source is turned on M To avoid triggering the safety circuit.
A threshold setting module: the setting of the threshold voltage is realized by a digital-analog conversion chip. The digital signal is sent out by the threshold control module and can be corrected according to different systems.
A threshold readback module: the readback of the threshold voltage is achieved by an analog-to-digital conversion chip. The setting of the threshold voltage in the monitoring system is of great importance, and the validity and the accuracy of the setting of the threshold voltage are ensured through threshold readback. The closed loop arrangement mode can ensure the safe operation of the whole method, thereby improving the stability and safety of the system.
A threshold control module: setting the threshold voltage and reading back the threshold voltage, comparing and judging whether the threshold voltage is within an allowable range, and realizing closed loop setting of the threshold voltage.
And a position monitoring module: as shown in fig. 4, the galvanometer position signal fed back by the scanning galvanometer drive is compared with the set position threshold voltage through the comparator by the absolute value circuit, and a digital signal of the comparison result is output for the logic judgment module. If the galvanometer position is greater than the threshold value, the light source scanning point is outside the scanning field of view, otherwise, the light source scanning point is inside the scanning field of view. The light source scanning point can trigger the speed monitoring module when the scanning field is within the scanning field of view, otherwise, the speed monitoring module is not triggered. This design is also entirely analog, with the aim of simplicity to ensure maximum reliability.
The logic judgment module is used for: and receiving feedback signals of the power monitoring module and the speed monitoring module, giving a signal of whether the light source is turned off or not, and feeding back the signal to the light source control module to change the working state of the light source.
In this embodiment, the light beam output by the light source is split by the TAPD, most of the light is used as the light beam for the detection light path, a small part of the light is used as the light beam for power monitoring, and then the light beam for power monitoring is used for outputting a current signal with a corresponding magnitude after passing through the integrated photodetector in the TAPD, as shown in fig. 2, further details of the power monitoring module are given. The power of the light beam of the detection light path must be ensured within the safety range of human eyes(e.g. setting the upper limit of the eye-safe power value to P s ) Let the ratio of the monitor light to the probe light power be gamma, in this embodiment gamma < 1/10. So that the power P of the power monitoring beam must satisfy 0 < P < gamma P s At this time, the power monitoring module outputs a high level to the logic judgment module. If the power monitoring module detects that the power P is more than or equal to gamma P s Or p=0, the low level is output to the logic determination module.
The scanning galvanometer drives the galvanometer position signal that returns of feedback, converts the voltage signal that is correlated with the galvanometer speed after processing through speed monitoring module. If the voltage signal is greater than the speed threshold voltage, the speed monitoring module outputs a high level to the logic judging module, otherwise, if the voltage signal is less than or equal to the speed threshold voltage, the speed monitoring module outputs a low level to the logic judging module.
The logic judging module receives the digital signals input by the power monitoring, speed monitoring and position monitoring module, and carries out state judgment and corresponding operation execution according to the flow chart shown in fig. 5. These decisions and operations are implemented in a programmable logic chip to achieve automatic security.
As shown in fig. 5, power on sets the thresholds for power monitoring and speed monitoring, respectively. If the difference between the readback threshold and the set threshold is within the allowable range, the scanning galvanometer is turned on and the speed monitoring module is reset to start monitoring, otherwise, the light source is turned off and a safety warning is given. And after the speed monitoring is started, if the speed is greater than a set threshold value or the position of the vibrating mirror is greater than the set threshold value, the light source can be turned on at the moment, and otherwise, the light source is turned off and a safety warning is given. After the light source is turned on, the power monitoring module is reset to start monitoring, the module can automatically judge whether the light beam power is smaller than the safety power threshold value, if so, the normal operation mode is entered, otherwise, the light source is turned off, and safety warning is given. After entering a normal operation mode, the speed monitoring module, the power monitoring module and the position monitoring module can simultaneously start automatic monitoring in parallel, the following two conditions occur, and the logic judging module can automatically turn off the light source and give a safety warning: a) The scanning position is in the scanning field of view (the position monitoring module judges that the position is smaller than the position threshold value), and the scanning speed is smaller than or equal to the speed threshold value; b) The beam power is greater than or equal to the safe power threshold.
As shown in fig. 6, the power monitoring module specifically includes: the power monitoring signal output by TAPD is input into the power monitoring module by P23, is subjected to low-pass filtering by U52A and U52B after passing through a transimpedance amplifier U4, and is subjected to threshold comparison by a comparator U5.
As shown in fig. 7, the speed monitoring module specifically includes: the position signals of the two vibrating mirrors are respectively input into a differential circuit formed by U28A and U28B and converted into speed signals; then the absolute value circuit formed by U27 and U30 is passed through, then U29A is added, then the absolute value circuit formed by U29B is passed through, and then the threshold value comparison is made by comparator U26.
As shown in fig. 8, the threshold setting module performs the threshold setting function by a two-channel analog-to-digital conversion chip U50.
As shown in fig. 9, the threshold readback module is specifically: after the two paths of threshold values pass through the U3C buffer operation amplifier and the U3D buffer operation amplifier respectively, a multichannel analog-to-digital conversion chip U8 completes the readback function of the threshold values.
As shown in fig. 10, the location monitoring module specifically includes: the position signals of the two vibrating mirrors are respectively input into an absolute value circuit formed by U46 and U48, and then are respectively converted into digital signals by a comparator U47 and a comparator U49, and are output to a logic judging module for judging whether scanning is in a field of view.
The invention ensures that the optical power of the optical scanning imaging device is in the safety range of human eyes, and if the detected light source power exceeds the preset safety standard or the scanning speed is smaller than the preset safety standard, the light source is turned off and the scanning point is moved out of the visual field of the optical scanning imaging device, so that the safety of ophthalmic medical treatment is ensured through the photoelectric element, the analog-digital circuit and the logic circuit.
Claims (8)
1. An automatic safety shield apparatus for an ophthalmic optical scanning imaging device, comprising: the system comprises a light source control module, a light source, a TAPD, a power monitoring module, a scanning galvanometer drive, a speed monitoring module, a threshold setting module, a threshold reading back module, a threshold control module, a position monitoring module and a logic judging module; the TAPD is an optical fiber beam splitter integrated with a light detector, the light source control module receives signals fed back by the logic judging module and controls the light source to be turned on or off, the light source outputs light beams for ophthalmic medical diagnosis and treatment, the TAPD divides the light beams emitted by the light source into two light beams according to different proportions, and the power monitoring module outputs and compares the results of the TAPD for the logic judging module to use; the scanning galvanometer controls the light beam to scan in a two-dimensional space, the scanning galvanometer drive controls the angle change of the galvanometer through a direct current signal, the speed monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, a digital signal of a comparison result is output for the logic judging module to use, the position monitoring module receives a galvanometer position signal fed back by the scanning galvanometer drive, and a digital signal of the comparison result is output for the logic judging module to use; the threshold control module realizes closed loop setting of threshold voltage, the threshold setting module realizes setting of threshold voltage by the digital-to-analog conversion chip, and the threshold readback module realizes readback of threshold voltage by the analog-to-digital conversion chip.
2. The automated safety shield apparatus for an ophthalmic optical scanning imaging device of claim 1, wherein the TAPD incorporates a photodetector that splits the light beam from the source into two light beams in different proportions, one for power monitoring and one for the diagnostic light path.
3. An automatic safety device for an ophthalmic optical scanning imaging apparatus as claimed in claim 1, wherein the power monitoring module is specifically: the power monitoring signal output by TAPD is input into the power monitoring module by P23, is subjected to low-pass filtering by U52A and U52B after passing through a transimpedance amplifier U4, and is subjected to threshold comparison by a comparator U5.
4. An automatic safety device for an ophthalmic optical scanning imaging apparatus as claimed in claim 1, wherein the speed monitoring module is specifically: the position signals of the two vibrating mirrors are respectively input into a differential circuit formed by U28A and U28B and converted into speed signals; then the absolute value circuit formed by U27 and U30 is passed through, then U29A is added, then the absolute value circuit formed by U29B is passed through, and then the threshold value comparison is made by comparator U26.
5. An automatic safety shield apparatus for an ophthalmic optical scanning imaging device as claimed in claim 1, wherein the threshold readback module is specifically: after the two paths of threshold values pass through the U3C buffer operation amplifier and the U3D buffer operation amplifier respectively, a multichannel analog-to-digital conversion chip U8 completes the readback function of the threshold values.
6. An automatic safety device for an ophthalmic optical scanning imaging apparatus as claimed in claim 1, wherein the position monitoring module is specifically: the position signals of the two vibrating mirrors are respectively input into an absolute value circuit formed by U46 and U48, and then are respectively converted into digital signals by a comparator U47 and a comparator U49, and are output to a logic judging module for judging whether scanning is in a field of view.
7. An automatic safety device for an ophthalmic optical scanning imaging apparatus as claimed in claim 1, wherein the integrated rate of motion v of the galvanometer must be greater than the minimum rate v required by safety standards M I.e. v.gtoreq.v M Whereinv x And v y The rates of the x-vibrating mirror and the y-vibrating mirror are respectively; />Can ensure that v is greater than or equal to v M As long as the monitoring circuit ensures that the sum of the absolute values of the speeds of the two scanning axes is greater than the safe minimum speed>The scanning speed is ensured to be larger than the threshold value by times, and the requirement on the safety monitoring of the scanning speed is met.
8. A method of protecting an automatic safety shield apparatus adapted for use with an ophthalmic optical scanning imaging device as defined in claim 1, comprising the steps of:
(1) Starting up to set threshold values of power monitoring and speed monitoring respectively, if the difference between the readback threshold value and the set threshold value is within an allowable range, turning on a scanning vibrating mirror and resetting a speed monitoring module to start monitoring, otherwise, turning off a light source and giving a safety warning;
(2) After the speed monitoring is started, if the speed is greater than a set threshold value or the position of the vibrating mirror is greater than the set threshold value, the light source can be turned on at the moment, and otherwise, the light source is turned off and a safety warning is given;
(3) After the light source is turned on, the power monitoring module is reset to start monitoring, the power monitoring module can automatically judge whether the light beam power is smaller than a safety power threshold value, if so, the normal operation mode is entered, otherwise, the light source is turned off and a safety warning is given;
(4) After entering a normal operation mode, the speed monitoring module, the power monitoring module and the position monitoring module can simultaneously start automatic monitoring in parallel, the following two conditions occur, the logic judging module can automatically turn off the light source and give out safety warning, the scanning position is in the scanning view field, and the scanning speed is smaller than or equal to the speed threshold value or the beam power is larger than or equal to the safety power threshold value.
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| CN110361716B (en) * | 2019-05-31 | 2023-12-22 | 上海波汇科技有限公司 | Human eye protection circuit for optical detection and ranging system |
| CN110932059B (en) * | 2019-10-31 | 2021-05-25 | 武汉新耐视智能科技有限责任公司 | T-shaped switching device for high-power optical fiber laser light path |
| CN113252302A (en) * | 2021-04-12 | 2021-08-13 | 深圳市大美光电有限公司 | Detection method and device of laser scanner and projection system |
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