Device for monitoring the mechanical integrity of eye-safe components of luminaires

Abstract

An apparatus for monitoring the mechanical integrity of an eye safety component of a luminaire is disclosed. The apparatus includes: a transducer operable to generate vibrations in the eye safety component; and a sensor operable to sense the vibrations in the eye safety component and output a signal representative of the sensed vibrations; and a processor operable to: monitor the signal from the sensor; determine whether the signal includes at least one parameter that falls outside a predetermined acceptable range, the predetermined acceptable range indicating mechanical integrity of the eye safety component; and initiate a safety action in response to determining that at least one parameter falls outside the predetermined acceptable range, indicating compromised mechanical integrity.

Description

Technical Field

[0001] The disclosure relates to an apparatus and method for monitoring the mechanical integrity of eye-safe components of a luminaire. The disclosure also relates to a luminaire comprising the apparatus and an apparatus comprising the luminaire. Background Art

[0002] There is a trend towards using 3D sensing for face recognition and world-facing applications. Such sensing systems require an illuminator to illuminate the target object to be imaged with light, and typically use a high-power laser. When the laser is properly packaged in a suitable optical module, it is eye-safe. However, if the module integrity is compromised, the illuminator may no longer be eye-safe, and in this case, an interlock is required to trigger the eye safety mechanism.

[0003] To date, the integrity of illuminator modules has been assessed using photodiode back reflection from the cover optics or using an indium tin oxide (ITO) layer on the cover optics and measuring the capacitance or DC resistance of the ITO layer.

[0004] More specifically, capacitive sensors are used to detect capacitance changes caused by cracks in the coated cover optics, which in turn could cause eye damage. However, the presence of large currents (e.g., up to 3A) used to drive the lasers in the illuminators with very short pulses (>100MHz) makes the measurement of the small values ​​(typically about 1pF) associated with the capacitance of the ITO layer very difficult.

[0005] The DC resistance of a resistive sensor can be checked in order to check the integrity of the cover optics that provide the conductive ITO layer. However, the conductive ITO layer must be outside the illumination field, so any damage to the uncoated cover optics may not be detected. In addition, the use of DC resistance measurements may be affected by naturally high noise environments due to electromagnetic interference (EMI), especially if a DC threshold reading is used.

[0006] It is therefore an object of the present disclosure to provide an apparatus and method for monitoring the mechanical integrity of eye-safe components of a luminaire that addresses one or more of the above-mentioned problems or at least provides a useful alternative. Summary of the invention

[0007] In general, the present disclosure proposes to overcome the above-mentioned problems by using vibrations to detect the mechanical properties of the cover optics, thereby directly monitoring the integrity of the eye-safe components in the illuminated area.

[0008] According to one aspect of the present disclosure, there is provided an apparatus for monitoring the mechanical integrity of an eye-safe component of a luminaire, the apparatus comprising:

[0009] a transducer operable to generate vibrations in the eyesafe component; and

[0010] a sensor operable to sense vibrations in the eye-safe component and output a signal representative of the sensed vibrations; and

[0011] A processor operable to:

[0012] Monitor the signals from the sensors;

[0013] determining whether the signal includes at least one parameter that falls outside of a predetermined acceptable range, the predetermined acceptable range being indicative of the mechanical integrity of the eyesafe component; and

[0014] In response to determining that at least one parameter falls outside of a predetermined acceptable range, indicating a compromise of mechanical integrity, a safety action is initiated.

[0015] Thus, embodiments of the disclosure provide a device for monitoring the mechanical integrity of an eye safety component of a luminaire that can be used to provide a safety interlock that is triggered when a vibration signal changes in response to a mechanical change in the eye safety component itself. Because the vibration is generated by a transducer acting on the eye safety component, the device can monitor the portion of the eye safety component through which light passes, thereby testing the mechanical integrity of the medium in the precise area where eye safety is critical. This is in contrast to prior art systems in which any monitoring is performed by detecting electrical signals from areas that are close to, but not coexisting with, the critical eye safety component. In addition, various aspects of the disclosure allow for continuous monitoring of window integrity in a luminaire through continuous transducer actuation.

[0016] In some embodiments, the vibration is generated directly by the operation of the transducer, so that the vibration is synchronized with the operation of the transducer. Therefore, if the sensor is pulsed, the vibration will also exist as a pulse signal within a well-defined detection window. In another embodiment, the vibration may come from the continuous operation of the transducer. In some embodiments, the transducer may have a vibration frequency that can be modulated to scan a range of frequencies or detect a specific frequency.

[0017]

[0013] Accordingly, various aspects of the present disclosure provide a device for monitoring the mechanical integrity of eye-safe components, such as those in illuminators configured for 3D sensing applications, and for initiating a safety action in response to a loss of integrity, thereby providing a safety interlock.

[0018] The transducer may also be a sensor. In other words, the transducer and the sensor may be formed as a single component capable of generating and sensing vibrations.

[0019] The phononic structure may be configured to improve the signal-to-noise ratio of the sensed vibrations. In other words, the phononic structure may enhance the signal generated by the sensor in the eye safety component itself or in the path from the eye safety component to the sensor. In certain embodiments, the phononic structure may be provided in, on, beside, near, around, or interlaced with the eye safety component (i.e., the phononic structure may be separate from or integrated with the structure forming the eye safety component).

[0020] The processor may also be operable to detect changes in ambient conditions within the luminaire based on the signal from the sensor.

[0021] The processor may initiate a safety action by sending instructions to the luminaires to modify the lighting intensity.

[0022] The processor can initiate a safety action by sending a command to the luminaire to stop lighting. Thus, the device can be configured as an automatic power control for the luminaire.

[0023] The sensor may include at least one of a microphone, an ultrasonic transducer, a piezoelectric transducer, or a resonant ultrasonic spectroscopy sensor. In some embodiments, multiple microphones may be used, each configured to sense a different area of ​​the eye safety component and / or tuned to sense a different mechanical vibration resonance. In some embodiments, multiple ultrasonic transducers, piezoelectric transducers, or resonant ultrasonic spectroscopy sensors may be used, each configured to detect a different area of ​​the eye safety component or tuned to sense a different mechanical vibration resonance.

[0024] The vibration may be at a predetermined frequency such that the processor may use the predetermined frequency in a lock detection method and / or a gate detection method when monitoring the signal from the sensor.

[0025] The apparatus may further include one or more of a signal generator, an amplifier, a filter; a lock detector; and an acceptable range detector.

[0026] The signal generator can be configured to generate sawtooth, square, sine, or arbitrary waveforms. The filter can be a low-pass, high-pass, or notch filter. The filter can be an absorption, interference, or dichroic filter.

[0027] According to a second aspect of the disclosure, there is provided a luminaire comprising:

[0028] at least one transmitter;

[0029] an eye safety component providing a barrier between at least one emitter and a user; and

[0030] An apparatus according to a first aspect of the disclosure.

[0031] The sensor may be configured to directly sense vibrations in the eye-safe component.

[0032] The sensor may be configured to indirectly sense vibrations in the eye-safe component by receiving input through a waveguide or other medium.

[0033] At least one emitter may include a laser.

[0034] The eye-safe component may include a glass substrate and / or a diffuser (or homogenizer, scatterer, diffuser).

[0035] The luminaire may be provided in the form of a package or module. The package or module may be airtight or sealed. A sealed package may contain a well-defined fluid (e.g., a gas) through which vibrations are propagated so that any leakage or intrusion (e.g., water or other fluid) can be detected by a change in the signal.

[0036] The processor may be included in the package / module, or may be provided externally, for example, elsewhere in a device containing the luminaire. If an external processor is used, it is at least configured to communicate with the sensor and emitter.

[0037] The sensor (e.g., microphone) may be located on or near the eye-safe component to ensure fast response and good signal quality. The sensor may be provided (i.e., fixed in place) on a portion of the eye-safe component (e.g., a diffuser or glass substrate), and metal traces provided to route electrical signals from the sensor to the edge of the package and along the sidewalls to the substrate where the processor and / or emitter are located.

[0038] In certain embodiments, a phononic or acoustic filter may be provided (eg, on the eye safety component or elsewhere in the package) to maximize the vibration signal strength along the sensor path.

[0039] For example, the sensor may be provided in a general integrated circuit (IC) or an application specific integrated circuit (ASIC) together with other components to perform functions of amplification, filtering, lock detection, threshold detection, and signal output for safety actions.

[0040] According to a third aspect of the disclosure, there is provided a device comprising the device according to the first aspect of the disclosure or the luminaire according to the second aspect of the disclosure.

[0041] According to a fourth aspect of the disclosure, there is provided a method for monitoring the mechanical integrity of an eye-safe component of a luminaire, the method comprising:

[0042] operating the transducer to generate vibrations in the eye-safe component;

[0043] obtaining a signal from the sensor representing the sensed vibration in the eye-safe component;

[0044] Monitoring signals;

[0045] determining whether the signal includes at least one parameter that falls outside of a predetermined acceptable range, the predetermined acceptable range being indicative of the mechanical integrity of the eyesafe component; and

[0046] A safety action is initiated in response to determining that at least one parameter falls outside of a predetermined acceptable range, thereby indicating a compromise of mechanical integrity.

[0047] The method may further include establishing a predetermined acceptable range (eg, a threshold).

[0048] The predetermined acceptable range may be established by a controller, which may be in the luminaire or provided externally (eg, in a host device).

[0049] The predetermined acceptable range may be based on predefined values ​​stored in a memory and / or defined during a calibration step. The predefined values ​​may include one or more parameters that may be adjusted during the calibration step. For example, the parameters may include signal amplitude, signal frequency, or signal wavelength.

[0050] An artificial neural network (ANN) can be used to establish the predetermined acceptable range.

[0051] According to a fifth aspect of the disclosure, there is provided a non-transitory computer-readable medium storing program instructions for causing at least one processor to execute the method according to the fourth aspect of the disclosure.

[0052] As discussed above, prior art systems often suffer from problems associated with measuring small values ​​and the fact that the area being monitored is different from the area through which the emitted and potentially damaging light passes.

[0053] Compared to such known systems, the device disclosed herein for monitoring the mechanical integrity of eye-safe components of a luminaire has the following advantages:

[0054] 1. It can accurately detect the area illuminated by the emitter (which is safety critical) because the vibrations are transmitted to the vicinity of the area of ​​the eye-safe component illuminated by the emitter and are configured to pass through the area.

[0055] 2. It can monitor the mechanical status of the eye-safe component itself (i.e. the glass window).

[0056] 3. It can be robust to noise, for example due to monitoring the reduced bandwidth from the lock detection method and a well-defined time window.

[0057] 4. It is only sensitive to the excitation frequency of the sensor.

[0058] 5. It can be used to monitor the class within the luminaire package (e.g. to detect leakage or ingress).

[0059] Finally, the present apparatus disclosed herein for monitoring the mechanical integrity of eye-safe components of a luminaire utilizes a novel approach in which, at least, it generates and monitors vibrations to provide an indication of the mechanical integrity of the eye-safe components in areas of primary concern. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Some embodiments of the disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0061] Figure 1 shows a block diagram of an apparatus having a luminaire and a device according to the present disclosure;

[0062] Figure 2 Shown is a method for monitoring Figure 1 A flow chart of a method for determining the mechanical integrity of an eye-safe component of a luminaire;

[0063] Figure 3 shows a side schematic view of a first illuminator according to the present disclosure;

[0064] Figure 4 shows a side schematic view of a second illuminator according to the present disclosure;

[0065] Figure 5 shows a side schematic view of a third illuminator according to the present disclosure;

[0066] Figure 6 shows a side schematic view of a fourth illuminator according to the present disclosure;

[0067] Figure 7 shows a side schematic view of a fifth illuminator according to the present disclosure;

[0068] Figure 8 Shown in the description Figure 1 A timing diagram of different signals generated during pulsed operation of an illuminator; and

[0069] Fig. 9 Shown in the description Figure 1 A second timing diagram of different signals generated during continuous operation of the luminaire. DETAILED DESCRIPTION

[0070] Generally speaking, the disclosure provides a method and apparatus for monitoring the mechanical integrity of eye safety components of a luminaire by sensing vibrations induced by a transducer through a cover glass or window as a means of monitoring whether the window is damaged.

[0071] Some examples of solutions are given in the attached figures.

[0072] Figure 1 A block diagram of a device 112 is shown having a luminaire 106 and an apparatus 100 for monitoring the mechanical integrity of an eye safety component 110 of the luminaire 106 in accordance with the present disclosure. The device 112 may be, for example, a cell phone, tablet, laptop, watch, or other computing device.

[0073] The device 100 includes a transducer 103, a sensor 102 in the form of a microphone, and a processor 104. The transducer 103 is operable to generate vibrations in the eye safety component 110. The sensor 102 is operable to sense the vibrations in the eye safety component 110 and output a signal representative of the sensed vibrations. The processor 104 is operable to: monitor the signal from the sensor 102; determine whether the signal includes at least one parameter that falls outside a predetermined acceptable range, the predetermined acceptable range indicating mechanical integrity of the eye safety component 110; and initiate a safety action in response to determining that the at least one parameter falls outside the predetermined acceptable range, indicating that the mechanical integrity is compromised.

[0074] The safety action may include sending instructions to the illuminator 106 to modify the lighting intensity (e.g., reduce the intensity to a safe level) or to stop the lighting. The safety action may include modifying the wavelength of the illuminator or switching the lighting from continuous to pulsed.

[0075] The illuminator 106 includes an emitter 108 and an eye safety component 110. The eye safety component 110 is configured to provide a barrier (not shown) between the emitter 108 and a user. The eye safety component 110 may include a diffuser and / or a transparent window (eg, a cover glass).

[0076] Although processor 104 is shown external to luminaire 106 , it may be incorporated within luminaire 106 and may be provided on an integrated circuit (IC) with sensor 102 , transducer 103 , and / or transmitter 108 , for example.

[0077] Figure 2A method 200 is shown that may be performed by the processor 104 for monitoring the mechanical integrity of the eye safety component 110. The method 200 includes a step 202 of operating a transducer to generate vibrations in the eye safety component 110. The method 200 also includes a step 204 of obtaining a signal representative of the sensed vibrations in the eye safety component 110 from the sensor 102 and a step 206 of monitoring the signal. A further step 208 includes determining whether the signal includes at least one parameter that falls outside of a predetermined acceptable range, the predetermined acceptable range indicating the mechanical integrity of the eye safety component 110. A subsequent step 210 includes initiating a safety action in response to determining that the at least one parameter falls outside of the predetermined acceptable range, thereby indicating that the mechanical integrity is compromised.

[0078] The method may further include establishing a predetermined acceptable range (eg, a threshold value).The predetermined acceptable range may be established by a controller, which may be in the luminaire or provided externally (eg, in a host device).

[0079] The predetermined acceptable range may be in the following forms: up to a predefined value; below a predefined value; between predefined values.

[0080] The predetermined acceptable range may be based on predefined values ​​stored in a memory and / or defined during a calibration step. The predefined values ​​may include one or more parameters that may be adjusted during the calibration step. For example, the parameters may include signal amplitude, signal frequency, or signal wavelength.

[0081] In certain embodiments, an artificial neural network (ANN) may be used to establish the predetermined acceptable range.

[0082] Figure 3 A side schematic diagram of a first (open) luminaire 300 according to the present disclosure is shown. The first luminaire 300 has a similar structure to that of the luminaire 106 and comprises a transducer 303 in the form of a piezoelectric transducer and a sensor 302 in the form of a microphone.

[0083] An emitter 306 in the form of a vertical cavity surface emitting laser (VCSEL) is mounted on the substrate 304 and arranged to emit light in the form of a laser beam 312 through a diffuser 308 and a glass window 310. The diffuser 308 and the glass window 310 together form the eye safety component 110.

[0084] Although not shown, a processor (similar to Figure 1 The processor 104) communicates with the converter 303, the sensor 302 and the transmitter 306.

[0085] In this embodiment, both the transducer 303 and the sensor 302 are mounted in direct contact with the glass window 310 of the eye safety component 110. In other embodiments, the transducer 303, the sensor 302, or both may be mounted in direct contact with the diffuser 308. In both cases, the sensor 303 and the sensor 302 are located on or near the eye safety component 110 to ensure fast response and good signal quality. Figure 3 306 , but metallic traces or other electrical connectors (eg, wires) may be provided to route electrical signals from transducer 303 and / or sensor 302 to processor and / or transmitter 306 .

[0086] In use, the transducer 303 is operable to generate vibrations in the glass window 310 and the sensor 302 is operable to sense the vibrations and output a signal representative of the sensed vibrations to the processor. The processor is operable to: monitor the signal from the sensor 302; determine whether the signal includes at least one parameter that falls outside a predetermined acceptable range, the predetermined acceptable range being indicative of the mechanical integrity of the glass window 310; and initiate a safety action in response to determining that the at least one parameter falls outside the predetermined acceptable range, thereby indicating a loss of mechanical integrity.

[0087] As described above, the safety action may include sending instructions to the luminaire 300 to modify the illumination intensity (e.g., reduce the intensity to a safe level) or to stop illumination. The safety action may include modifying the wavelength of the luminaire or switching the illumination from continuous to pulsed.

[0088] Figure 4 A side schematic diagram of a second (enclosed) luminaire 400 according to the present disclosure is shown. The second luminaire 400 is similar to the first luminaire 300, and thus the same reference numerals are included to indicate similar features. Figure 3 In addition to the described components, the second illuminator 400 is packaged in a package or module including a sidewall 402 between the substrate 304 and the glass window 310. Therefore, the second illuminator 400 can be airtight or hermetically sealed and can contain a well-defined fluid (e.g., a gas). In this case, the sensor 302 can sense the vibration signal generated in the diffuser and / or the glass window 310 that has passed through the fluid, so that any leakage or fluid intrusion can be detected by changes in the vibration signal.

[0089] Figure 5 A side schematic diagram of a third (additional) luminaire 500 according to the present disclosure is shown. The third luminaire 500 is similar to the second luminaire 400, and thus the same reference numerals are included to indicate similar features. However, instead of Figure 4 The sensor 302 is mounted on the glass window 310. Figure 5 In the embodiment, sensor 302 is mounted on substrate 304. In some embodiments, both transducer 303 and sensor 302 may be mounted on substrate 304. Figure 5 , but metal traces or other electrical connectors (eg, wires) may be provided to route electrical signals from the transformer 303 to the edge of the luminaire package and along the sidewalls 402 to the substrate 304 where the emitter 306 (and possibly the processor) is located.

[0090] Figure 6 A side view schematic diagram of a fourth (additional) illuminator 600 according to the present disclosure is shown. The fourth illuminator 600 is similar to the third illuminator 500 and therefore includes the same reference numerals to indicate similar features. However, in this case, a metal line (i.e., a connector) 602 providing an electrical signal path between the transducer 303 and the substrate 304 is shown. In this way, the signal for operating the transducer to induce vibration can be controlled by a processor provided on the substrate 304. As described above, the processor will additionally determine whether the signal from the sensor 302 includes at least one parameter that falls outside a predetermined acceptable range, and the predetermined acceptable range indicates the mechanical integrity of the glass window 310. The processor, in response to determining that at least one parameter falls outside a predetermined acceptable range, initiates a safety action, thereby indicating a compromise of mechanical integrity. For example, the processor can transmit a trigger instruction for shutting down power to the transmitter 306 to prevent continued illumination in the event of a loss of integrity of the eye safety component.

[0091] Figure 7 A side schematic diagram of a fifth (combined) luminaire 700 according to the present disclosure is shown. The fifth luminaire 700 is similar to the fourth luminaire 600 and therefore includes the same reference numerals to indicate similar features. However, instead of the transducer 303 and the sensor 302 being separate components, they are combined into one component 702 that performs the functions of both the transducer 303 and the sensor 302.

[0092] Figure 8 Shown in the description Figure 1FIG. 8 is a first (pulse) timing diagram 800 of different signals generated during operation of the illuminator 106 of FIG. 8. It will be appreciated that the illuminators 300, 400, 500, 600, and 700 may also be operated in a similar manner. The timing diagram 800 includes an x-axis representing time and a y-axis representing signal amplitude / intensity. Arbitrary units (AU) are shown because the diagram is for illustration purposes only. The waveforms shown represent a transducer signal intensity 802, a vibration signal amplitude 804, a gated vibration signal amplitude 806, a noise signal amplitude 808, and a detection gate signal amplitude 810, which are purely illustrative and other shapes of these waveforms may exist in a real device.

[0093] Timing diagram 800 shows a pulsed vibration signal 802 from a transducer. This results in a vibration signal 804 that passes through the eye safety component. The vibration signal 804 propagates in the eye safety component and is transmitted through the side walls and the enclosing medium. Thus, the vibration signal 804 is sensed by a sensor that is provided on the eye safety component or elsewhere in the luminaire. In this embodiment, a gated detection approach is used by generating a detection gate signal 810 that is timed to isolate a portion of the vibration signal 804, which is represented as a gated vibration signal 806, and the gated vibration signal 806 is caused by the transmission of the vibration signal 804 in the eye safety component. Thus, the gated vibration signal 806 sensed by the sensor is the product of the detection gate signal 810 and the vibration signal 804. In addition, as shown in FIG. Figure 8 As shown, a noise signal 808 is also present.

[0094] In the present embodiment, the transducer may not induce vibrations at the resonant frequency of the glass window. Therefore, the vibration signal 804 may be relatively small, and the resulting gated vibration signal 806 may be similarly small.

[0095] like Figure 8 As shown, the gated vibration signal 806 is delayed in time relative to the transducer signal 802. This is simply a result of the speed of sound in the medium, so it allows easy determination of the parameters of the detection gate signal 810. However, instead of using Figure 8 As shown, the detection gate signal 810 may be used so as to completely overlap the vibration signal 804 .

[0096] The mechanical integrity of the eye-safe component can be checked by monitoring the vibration signal 804 or the gated vibration signal 806. Since acoustic waves are very sensitive to structural defects, the condition of the eye-safe component can be observed at any time while the transducer is in use.

[0097] In certain embodiments, the vibration signal amplitude is measured to indicate the mechanical integrity of the eye safety component. The indication may be obtained by storing a value of the vibration signal amplitude in a memory and comparing the value with a new measured value using a processor. Here, any difference in the value will correspond to a mechanical integrity failure in the eye safety component. However, the variability of the value due to system tolerances may be taken into account in the comparison, so an acceptable range around a typical value may be allowed, so that the safety action is triggered only when the vibration signal amplitude exceeds the acceptable range.

[0098] In certain embodiments, spectral components of the vibration signal may be measured to indicate the mechanical integrity of the eye-safe component. The indication may be obtained by storing the values ​​of the spectral components, such as those obtained by Fourier transform, in a memory and comparing the values ​​with new measured values ​​using a processor. As described above, any difference in the values ​​(given an acceptable tolerance level) may correspond to a mechanical integrity failure in the eye-safe component.

[0099] In certain embodiments, the vibration signal decay time may be measured to indicate the mechanical integrity of the eye safety component. This indication may be obtained by storing a value of the vibration signal decay time in a memory and using a processor to compare that value to a new measured value. Again, any difference in the values ​​(taking into account acceptable tolerance levels) will correspond to a mechanical integrity failure in the eye safety component.

[0100] In certain embodiments, the amplitude, voltage, or frequency required to drive the transducer may be measured to indicate the mechanical integrity of the eye safety component. This indication may be obtained by storing values ​​of the amplitude, voltage, or frequency in a memory and using a processor to compare these values ​​to new measured values. As described above, any difference in the values ​​(taking into account acceptable tolerance levels) will correspond to a mechanical integrity failure in the eye safety component.

[0101] While the sensor may include a standard microphone, custom micro-electromechanical system (MEMS) based microphones can be used to achieve sensitivities as high as 1-10 V / Pa.

[0102] Although not shown, a phononic structure may be provided to improve the signal-to-noise ratio of the vibration signal.

[0103] Fig. 9 Shown in the description Figure 1103 of the present invention. The second (continuous) timing diagram 900 of different signals generated during the continuous operation of the converter 103 of FIG. The second (continuous) timing diagram 900 is similar to the first (pulse) timing diagram 800 and therefore includes the same reference numerals to indicate similar features. The timing diagram 900 includes an x-axis representing time and a y-axis representing signal amplitude / intensity. Arbitrary units (AU) are shown because the figure is only for illustrative purposes. The waveforms shown represent the converter signal intensity 802, the vibration signal amplitude 804 and the noise signal amplitude 808, which are purely illustrative and other shapes of these waveforms may exist in real devices.

[0104] Timing diagram 900 shows vibration signal 802 as a continuous signal from a sensor that sweeps a predetermined frequency range. This results in vibration signal 804. Vibration signal 804 propagates in the eye-safe component and is also transmitted through the sidewalls and the enclosing medium. Thus, vibration signal 804 is sensed by a sensor that is provided on the eye-safe component or elsewhere in the luminaire.

[0105] The vibration signal 804 is delayed from the transducer signal 802 by an amount of time corresponding to the speed of sound in the eye safety component. Fig. 9 8 as the time difference between marker 909 and marker 911. The oscillation frequency of the transducer signal 802 that is closest to the resonant frequency of the window is marked 911. Marker 909 represents the same resonant frequency in the vibration signal 804, which is delayed due to the speed of sound in the eye safety component.

[0106] The delay between the marks 911 and 909 can be used to indicate the mechanical integrity of the eye safety component. This indication can be obtained by storing the value of the time difference between the marks 911 and 909 in a memory and comparing this value with the new measurement value using a processor. Here, any difference in the value (taking into account the acceptable tolerance level) will correspond to a mechanical integrity failure in the eye safety component.

[0107] Similarly, the resonant frequency of the eye safety component when measured by the sensor (i.e., corresponding to the mark 909 on the vibration signal 804) can be used to indicate the mechanical integrity of the eye safety component. This indication can be obtained by storing the value of the resonant frequency of the vibration signal 804 in a memory and comparing this value with the new measured value using a processor. Here, any difference in the value (given the acceptable tolerance level) will correspond to a mechanical integrity failure in the eye safety component.

[0108] In some embodiments, the amplitude of the vibration signal 804 can be used to indicate the mechanical integrity of the eye safety component. This indication can be obtained by storing the value of the amplitude of the vibration signal 804 in a memory and using a processor to compare this value with a new measurement value. Here, any difference in the value (given an acceptable tolerance level) will correspond to a mechanical integrity failure in the eye safety component.

[0109] Thus, examples of the present disclosure provide a method and apparatus that uses mechanical vibrations to detect the mechanical properties of eye-safe components for luminaires to monitor the integrity of the eye-safe components and perform safety actions, such as shutting down the emitter, when changes occur.

[0110] Examples of the present disclosure may be used in many different applications, including world illuminators and front illuminators for 3D sensing (using, for example, time-of-flight (TOF), modal, or stereo methods) or augmented reality, such as in gaming, industrial, education, automotive (e.g., for driver monitoring), and other industries.

[0111] List of reference numerals:

[0112] 100 Installations

[0113] 102 Sensors

[0114] 103 Converter

[0115] 104 Processor

[0116] 106 illuminators

[0117] 108 Transmitter

[0118] 110 Eye safety parts

[0119] 112 Equipment

[0120] 200 Methods

[0121] 202 Step 1

[0122] 204 Step 2

[0123] 206 Step 3

[0124] 208 Step 4

[0125] 210 Step 5

[0126] 300 First (open) illuminator

[0127] 302 Sensor

[0128] 303 Transformer

[0129] 304 substrate

[0130] 306 Launcher

[0131] 308 Diffuser

[0132] 310 Glass Window

[0133] 312 Laser Beam

[0134] 400 Second (enclosed) illuminator

[0135] 402 Sidewall

[0136] 500 Third (additional) illuminator

[0137] 600 Fourth (additional) illuminator

[0138] 602 connections

[0139] 700 Fifth (combination) illuminator

[0140] 702 Combined Transducer and Sensor

[0141] 800 Signal Graph (Pulse)

[0142] 802 Transducer Signal Strength

[0143] 804 Vibration signal amplitude

[0144] 806 Gated vibration signal amplitude

[0145] 808 Noise signal amplitude

[0146] 810 Detection gate signal amplitude

[0147] 900 Signal graph (continuous)

[0148] 909 The resonant frequency of the window when measured by the sensor

[0149] 911 The resonant frequency of the window when it is transmitted by the converter

[0150] Those skilled in the art will appreciate that in the foregoing description and the appended claims, positional terms such as "above," "along," "side," etc., refer to conceptual views, such as those shown in the accompanying drawings. These terms are used for ease of reference and are not meant to be limiting. Therefore, these terms should be understood to refer to an object when in the orientation shown in the accompanying drawings.

[0151] Although the disclosure has been described in terms of the preferred embodiments described above, it should be understood that these embodiments are illustrative only and the claims are not limited to these embodiments. Those skilled in the art will be able to make modifications and substitutions based on the disclosure, and these modifications and substitutions are considered to fall within the scope of the appended claims. Each feature disclosed or described in this specification may be incorporated into any embodiment, either alone or in any appropriate combination with any other features disclosed or described therein.

[0152] refer to

[0153] Other background technologies related to the present invention are cited as follows:

[0154] 1.Applications of photoacoustic sensing techniques,ACTam,Reviews ofModern Physics,Vol 58,No.2,p.381-431(1986)

[0155] 2. Optimized Capacitive MEMS Microphone for Photoacoustic Spectroscopy (PAS) Applications, 10.1117 / 12.597136, Pedersen et al. (2005).

[0156] 3. https: / / phys.org / news / 2019-01-technology-lasers-transmit-audible-messag es.html

[0157] 4. Progress in Photothermal and Acoustic Science and Technology, Life and Earth Sciences, A. Mandelis and P. Hess, SPIE (1997).

[0158] 5. Surface crack detection with low-cost photoacoustic imaging system, https: / / doi.org / 10.14716 / ijtech.v9i1.1506

Claims

1. A device for monitoring the mechanical integrity of an eye-safe component of a luminaire, the device comprising: a transducer operable to generate vibrations in the eyesafe component; and a sensor operable to sense vibrations in the eye-safe component and output a signal representative of the sensed vibrations; and A processor operable to: monitoring signals from sensors; determining whether the signal includes at least one parameter that falls outside of a predetermined acceptable range, the predetermined acceptable range being indicative of the mechanical integrity of the eyesafe component; and In response to determining that at least one parameter falls outside of a predetermined acceptable range, indicating a compromise of mechanical integrity, a safety action is initiated.

2. The device of claim 1, wherein: Transducers are also sensors.

3. The device of claim 1 or 2, further comprising a phononic structure configured to improve the signal-to-noise ratio of the sensed vibrations.

4. An apparatus according to any preceding claim, wherein the processor is further operable to detect a change in environmental conditions within the luminaire based on a signal from the sensor.

5. A device according to any one of the preceding claims, wherein The processor is operable to initiate a security action by sending an instruction to the luminaire to modify the lighting intensity.

6. A device according to any one of the preceding claims, wherein: The processor can initiate a safety action by sending a command to the luminaire to stop lighting.

7. A device according to any one of the preceding claims, wherein The sensor includes at least one of a microphone, an ultrasonic transducer, a piezoelectric transducer, or a resonant ultrasonic spectroscopic sensor.

8. A device according to any one of the preceding claims, wherein The vibration is at a predetermined frequency, and wherein the processor is operable to use the predetermined frequency in a lock detection method and / or a gate detection method when monitoring the signal from the sensor.

9. The device according to any one of the preceding claims, wherein: The apparatus further includes one or more of a signal generator, an amplifier, a filter; a lock detector; and an acceptable range detector.

10. A lighting device, comprising: at least one transmitter; an eye safety component providing a barrier between at least one emitter and a user; and Apparatus as claimed in any preceding claim.

11. A luminaire according to claim 10, wherein the sensor is arranged to directly sense vibrations in the eye-safe component.

12. The luminaire of claim 10, wherein the sensor is arranged to sense vibrations in the eye-safe component indirectly by receiving input via a waveguide or other medium.

13. The luminaire of any one of claims 10 to 12, wherein said at least one emitter comprises a laser.

14. The luminaire of any of claims 10 to 13, wherein the eye safety component comprises a glass substrate and / or a diffuser.

15. An apparatus comprising a device according to any one of claims 1 to 9 or a luminaire according to any one of claims 10 to 14.

16. A method for monitoring the mechanical integrity of an eye-safe component of a luminaire, the method comprising: operating the transducer to generate vibrations in the eye-safe component; obtaining a signal from the sensor representing the sensed vibration in the eye-safe component; Monitoring signals; determining whether the signal includes at least one parameter that falls outside of a predetermined acceptable range, the predetermined acceptable range being indicative of the mechanical integrity of the eyesafe component; and A safety action is initiated in response to determining that at least one parameter falls outside of a predetermined acceptable range, thereby indicating a loss of mechanical integrity.

17. The method of claim 16, further comprising establishing the predetermined acceptable range using an artificial neural network.

18. A non-transitory computer readable medium storing program instructions for causing at least one processor to execute the method according to claim 16 or 17.

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