LED circuit breakers, LED lighting fixtures, and iris scanners
Patent Information
- Application Number
- JP2026520670
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-12
- Filing Date
- 2024-10-08
- Publication Date
- 2026-10-13
Smart Images
Figure 2026533920000001_ABST
Abstract
Description
[Technical Field]
[0001] This invention relates to a light emission diode (LED) circuit breaker and an LED circuit incorporating such a breaker. More specifically, the breaker of this invention is used to limit the emission of LED light corresponding to a hazardous level. This invention also relates to an LED illuminator for an iris scanner. [Background technology]
[0002] LED light is used in many applications. LED light is used in iris scanners to illuminate the iris. Recently, near-infrared (IR) light seems more suitable for human authentication because it provides more detail in the iris image. Since near-infrared light is invisible to the human eye, excessive IR illumination does not cause eyelid closure or pupil constriction. However, depending on the intensity and exposure time of IR, it can cause retinal damage. On the other hand, intensity and exposure time are generally determined by image quality, and one or more images are used to set the exposure time for the image sensor. Therefore, it is necessary to prevent IR exposure that could damage the eyes. [Overview of the project]
[0003] The present invention provides solutions to all problems with the LED circuit breaker according to claim 1, the LED circuit according to claim 7, and the iris scanner according to claim 8. Preferred embodiments of the present invention are defined in the dependent claims.
[0004] In a first aspect of the invention, the present invention provides a circuit breaker intended to be placed between an LED driver and an LED, the circuit breaker measuring the power driving the LED over time in order to shut off the LED circuit if the exposure time becomes excessive.
[0005] In particular, the present invention relates to an LED circuit breaker intended to be installed in series between an LED driver and an LED light source. The LED circuit breaker comprises a controlled switch, a sensor, and a control circuit. The controlled switch is installed in series between the LED driver and the LED light source to open and close the circuit. The sensor measures the power supplied to the LED light source by the LED driver. The sensor provides the measurement value. The control circuit is connected to the sensor to receive the measurement value and is connected to the controlled switch to control the controlled switch. The control circuit is configured to perform a time integral of the measurement value to obtain an illumination value representing the amount of illumination, and to open the controlled switch when the illumination value exceeds a predetermined threshold.
[0006] To account for the downtime between two illumination periods, the control circuit can be configured to reduce the illumination value when the measured value is equal to zero.
[0007] Prioritizing the reduction of illumination values, this can be done according to a constant gradient over time.
[0008] In a preferred embodiment, the sensor may be a current sensor, and the measurement value is a current measurement value.
[0009] To avoid malfunctions related to the power supply of the LED driver, the LED circuit breaker can be isolated from the LED driver and LED light source, the controlled switch is of relay type, and the current sensor is a Hall effect sensor.
[0010] To address the potential risk of overexposure, the control circuit may be configured to require an external action by the operator to reset the controlled switch after it has been opened, allowing the controlled switch to be closed again.
[0011] In a second aspect, the present invention provides an LED circuit comprising an LED driver and at least one LED light source connected to the LED driver, wherein the LED circuit comprises an LED circuit breaker according to the first aspect of the present invention.
[0012] In a third aspect, the present invention provides an iris scanner comprising a camera, an illuminator, and a central unit connected to a user interface, the central unit being positioned in front of the camera and controlling the illuminator and camera to capture an identification image of the iris illuminated by the illuminator, the illuminator being an LED circuit according to the second aspect.
[0013] According to a particular embodiment, the camera is an infrared camera, and the LED light source comprises infrared LEDs.
[0014] To avoid voltage coupling between different elements, the central unit can be connected to the control circuit of the LED circuit breaker via an insulating coupler, and the LED circuit breaker is equipped with an isolated power supply to provide power to its components, which are galvanically independent from the LED driver, the central unit, and the camera power supply.
[0015] All features and / or steps of the methods described herein (including the claims, description, and drawings) may be combined in any combination, except for any combination of mutually exclusive features and / or steps. [Brief explanation of the drawing]
[0016] These and other features and advantages of the present invention will be clearly understood by considering the detailed description of the invention, which will become apparent from preferred embodiments of the invention, which are given as examples and are not limited to those given, with reference to the drawings. [Figure 1] A block diagram of an iris scanner implementing the present invention is shown. [Figure 2] A first embodiment of the illuminator according to the present invention is described in detail. [Figure 3]An example of the energy counter used in the embodiment of Figure 2 is shown. [Figure 4] A second embodiment of the illuminator according to the present invention is shown in detail. [Figure 5] A flowchart executed by the control circuit of the embodiment of Figure 4 is shown. [Figure 6] Different signal diagrams corresponding to different use cases of the present invention are shown. [Figure 7] Different signal diagrams corresponding to different use cases of the present invention are shown. [Figure 8] Different signal diagrams corresponding to different use cases of the present invention are shown. [Figure 9] Different signal diagrams corresponding to different use cases of the present invention are shown. [Description of Embodiments]
[0017] As will be appreciated by those skilled in the art, aspects of the present invention may be embodied as an LED circuit breaker, an LED circuit, or an iris scanner.
[0018] For the sake of brevity in the description of the present invention, the same reference numerals may be used in a plurality of drawings to refer to the same or similar elements. To avoid repetition, elements previously described in one figure will not be described again, unless they have some modification in another figure.
[0019] First, Figure 1 corresponds to a block diagram of an iris scanner implementing the present invention. The iris scanner comprises a central unit 1, such as a personal computer, connected to an illuminator 2, a camera 3, and a user interface 4 via a communication interface. The camera 3 is preferably an infrared camera. The choice of an infrared camera allows for more characteristic detail of the iris, although other types of cameras can be used for visible or invisible light. The camera 3 is connected to the central unit 1 via a standard communication interface used for video, such as USB. The illuminator 2 is a controlled flash lamp connected to the central unit 1 via a standard interface to provide a flash of light whose intensity and duration are controlled by the central unit 1 as required by the central unit 1. In a preferred embodiment, the flash is an infrared flash, but it may be another type of light, the important thing being that the light from the illuminator 2 matches the light sensitivity of the camera 3. The user interface 4 may comprise a display, keyboard, mouse, and any possible interfaces that allow the user to interact with the computer. Depending on the use of the iris scanner, the user interface may be controlled by an operator or may be part of an autonomous system that allows a person to pass through a control gate.
[0020] In the case of an iris scanner under operator control, the person needs to position their eye 5 in front of the illuminator 2 and camera 3. The operator then instructs the camera to capture an iris image via the user interface 4. The central unit 1 simultaneously sends commands to the camera 3 and the illuminator 2. The illuminator 2 illuminates the eye 5 for several milliseconds, corresponding to the exposure time of the camera 3. The image is transferred from the camera to the central unit 1, which determines whether the image is good or not through image processing. If the image is too dark, a command is sent to the illuminator to increase the flash time to increase the light intensity, and another command is sent to take a new picture. If the image framing is inappropriate, a message can be sent to the user to move the eye 5 forward, backward, left, or right, and another image can be taken. In some cases, more than five images may be taken to obtain a good iris image.
[0021] In the case of an autonomous system, the user interface may further include a detection camera, which may be a stereoscopic camera. When a person is detected by the detection camera, the display can print a guidance message for that person to ensure they are correctly positioned in front of camera 3. When the detection camera detects a good position for the head, the user interface can trigger central unit 1 to capture an iris image. Central unit 1 controls camera 3 and illuminator 2 as described above using a system controlled by an operator. If the image is too dark, the exposure time can be adjusted to capture multiple images. If the iris image is poorly framed, a message can be sent to the user to move their eye 5 forward, backward, left, or right, and other images can be captured until the iris image is satisfactory. Several images can be captured to obtain a good iris image. Compared to an iris system controlled by an operator, the number of images captured by the autonomous system may be more important, and image acquisition may be faster.
[0022] As shown, using infrared imaging makes it possible to bring more detail to the iris in a photograph. Nevertheless, if exposure to infrared light is excessive, it can damage the retina. In addition, the eye does not have a protective reflective mechanism against infrared light. While infrared flashes are usually short enough to be safe for the subject, adjusting the exposure time or taking several images in succession may exceed safety standards for the human eye.
[0023] According to the present invention, the illuminator 2 uses LEDs in combination with an LED circuit breaker, which is described in more detail with reference to Figure 2. Figure 2 details a first embodiment of the illuminator 2. According to the present invention, the illuminator 2 comprises an LED driver 21, an LED light source 22, and an LED circuit breaker 23. The LED driver 21 may be a different known type that provides a control current or control voltage, which may be pulsed or non-pulsed. The LED driver can be controlled through a standard serial link. Many LED drivers are well known in the art and any type of driver can be used with the present invention, so they will not be described in detail. The LED light source 22 comprises several LEDs that are mounted in series or parallel and may cooperate with an optical system for focusing the LED light. In this embodiment, the LEDs are infrared LEDs, and the only important thing is to know the relationship between the global power supplied to the LEDs and the global light power supplied by the LEDs. Those skilled in the art will readily calculate the ratio between power and light power as a function of the number of LEDs and the selected LEDs.
[0024] The LED circuit breaker comprises a controlled switch 231, a sensor 232, and a control circuit 233. The controlled switch 231 is connected in series between the LED driver 21 and the LED light source 22 to open and close the circuit. The control switch 231 can be any type of switch that can be electrically controlled, such as any type of power transistor, relay, or otherwise. The sensor 232 is positioned on the LED circuit to measure the power supplied to the LED light source 22 by the LED driver 21. To simplify the sensor 232 and considering that the current i flowing through the LED is directly related to the light power, the sensor 232 can be any type of current sensor. The sensor 232 is positioned on a conductor connecting the LED driver 21 and the LED light source 22 and provides, for example, a measurement of voltage proportional to the current flowing through the conductor.
[0025] The control circuit 233 is connected to the sensor 232 to receive measurement values, to the controlled switch 231 to control said switch, and to the central circuit 1 to exchange information through a standard communication interface. In this first embodiment, the control circuit 233 comprises an energy counter 234 and a logic circuit 235. The energy counter 234 performs a time integral of measurement values to obtain an illumination value representing the amount of illumination, and to trigger an alarm signal when the amount of illumination exceeds a safe exposure time. The logic circuit 235 is connected to the energy counter 234, the controlled switch 231, and the central unit 1. The logic circuit 235 is configured to control the controlled switch 231 according to the alarm signal and commands received from the central unit 1. The logic circuit 235 closes the controlled switch 231 in response to receiving a start signal from the central unit 1 and opens the controlled switch 231 in response to the activation of the alarm signal. In addition, the logic circuit 235 sends a message to the central unit 1 when the alarm signal is activated.
[0026] If the amount of infrared energy received by the eye 5 becomes excessive over a period of time, infrared radiation is dangerous to the eye 5. The energy counter 234 is a circuit that counts the emitted energy over time so as not to exceed the energy that the eye can receive during this period. Figure 3 shows an embodiment of the energy counter 234.
[0027] The energy counter comprises an amplifier 310, a first comparator 320, an inverter 330, a first switch 340, a second switch 350, an integrator 360, and a second comparator 370. The amplifier 310 is a standard amplifier having an input connected to the sensor 232 and an output that provides a signal proportional to the measurement. The first comparator 320 comprises a first input, a second input, and an output. The first input of the first comparator 320 is connected to the output of the amplifier 310, and the second input is connected to a first threshold voltage V th1 The output of the first comparator 320 is obtained when the voltage of its first input is equal to the first threshold voltage V. th1 When it is higher than the first threshold voltage V, it provides an active signal, and the voltage of its first input is the first threshold voltage V th1 When it is lower than the first threshold voltage V, it provides an inactive signal. The role of this first comparator 320 is to determine whether the measurement indicates whether there is a current i flowing through the LED light source 22, and therefore the first threshold voltage V th1 This is a positive voltage that is close to zero volts but high enough to remove unwanted signals, but this always activates the output of the first comparator 320 when the current measurement is not zero.
[0028] The first and second switches 340 and 350 are controlled switches each having a control input and a first and a second terminal. The first and second switches 340 and 350 close the circuit between their first terminal and second terminal when the control input receives an active signal, and the first and second switches 340 and 350 open the circuit between their first terminal and second terminal when the control input receives an inactive signal. The control input of the first switch 340 is directly connected to the output of the first comparator 320, and the control input of the second switch 350 is connected to the output of the first comparator 320 through the inverter 330. The first terminal of the first switch 340 is connected to the output of the amplifier 310. The second terminal of the first switch 340 is connected to the first terminal of the second switch 350. The second terminal of the second switch 350 is connected to the reference voltage V Dec is connected to.
[0029] Integrator 360 is a standard integrator having an input and an output. Integrator 360 provides at its output a signal that is the time integral of the signal present at its input. The input of integrator 360 receives either the signal provided by the output of amplifier 310 or the reference voltage V Dec is connected to the second terminal of the first switch 340 and the first terminal of the second switch 350. The reference voltage V Dec is a negative voltage that decreases the output signal of integrator 360, and the signal from amplifier 310 increases the output signal of integrator 360.
[0030] The second comparator 370 comprises a first input, a second input, and an output. The first input of the second comparator 370 is connected to the output of integrator 360, and the second input receives the second threshold voltage V th2 . The output of the second comparator 370 provides an alarm signal. The second threshold voltage V th2 is a voltage corresponding to the maximum value of energy received by the eye over a certain period of time.
[0031] Before explaining how the circuit works based on a specific example, those skilled in the art will understand that such analog circuits are relatively complex to develop and adjust. Adjusting the time constant of the integrator 360 requires changing capacitors and / or resistors, which must be very precise. In addition, to change the decay time of the integrated signal, the reference voltage V Dec This needs to be changed, and a negative voltage adjustable signal generator is required. Finally, the amplifier 310 and integrator 360 may be sensitive to variations in the supply voltage Vcc.
[0032] Figure 4 shows a second embodiment of the illuminator 2 according to the present invention. This second embodiment solves the problems listed above by proposing a digital circuit. The second embodiment differs from the embodiment in Figure 2 in that the control circuit 233 is a microcontroller. The microcontroller must be a standard one that includes at least one analog input for receiving measurements from the sensor 232, at least one output for controlling the switch 231 to be controlled, and a standard communication port for exchanging data with the central unit 1.
[0033] Digital circuits may also be sensitive to power supply voltages and overvoltages arising from other circuits. The inventors propose an improvement that can also be used in the first embodiment, which completely isolates the LED circuit breaker 23 from the illuminator 2 and all other elements of the central circuit 1. Such isolation is achieved by using a switch 231 controlled only by a relay type, i.e., a mechanical relay or a solid-state relay. The sensor 232 may be a Hall effect current sensor. The connection between the control circuit 233 and the central unit 1 can be made through an insulating coupler 240, for example, an optocoupler, or through a magnetic non-contact link. An isolated power supply 241 is used to supply power to the control circuit 233 and to power each element of the LED circuit breaker 23. Such an isolated power supply 241 may be a known DC / DC converter that uses a transformer between the power input and power output, and this DC / DC converter is coupled to the power supply circuit of the LED driver 21.
[0034] Optionally, the start signal to close the controlled switch 231 may be directly managed by the LED circuit breaker 23 instead of being transmitted by the central circuit 1. A push-button circuit 242 can provide the start signal to the control circuit 233. Such a solution requires more operator movement to ensure that the time required for restart is minimized and that the operator is aware that an abnormal situation has occurred. Such an option is particularly useful for autonomous systems because they cannot have an input user interface, and therefore the operator can assist in capturing a person's iris image, and improper movements by the person can cause excessive image capture.
[0035] Using a microcontroller requires it to run a program. Figure 5 shows an example of a flowchart that a microcontroller can execute to monitor current and issue an alarm signal as needed.
[0036] The flowchart in Figure 5 begins with the end of idle step 501, which corresponds to the reception of a start signal transmitted from either the central unit 1 or the push-button circuit 242. Upon receiving the start signal, the first step 502 resets the counter value CNT to zero and switches the controlled switch 231 to ON.
[0037] In the second step 503, the measured current i is sampled at the input of the microcontroller and converted into digital data representing the measured current i. The first test step 504 compares the measured current i with a first threshold Th1. The first threshold Th1 corresponds to a small value close to zero but high enough to eliminate unwanted measurements. In one example, the first threshold may be equal to 0.5 percent of the nominal current required to light an LED in order to determine whether actual current is flowing through the LED. If the measured current I is higher than the first threshold Th1, the third step 505 is performed; if the measured current i is not higher than the first threshold Th1, the fourth step 506 is performed. The third step 505 involves incrementing the measured current value CNT, which is finally multiplied by a coefficient k, where k can be equal to 1 or any other value, depending on the bit size of the counter value CNT. The fourth step 506 consists of subtracting a decrease value Dec from the counter value CNT. Of course, the lowest counter value is zero, and if the decrease result is less than zero, the result of the counter value CNT is considered to be zero.
[0038] After the third step 505 or the fourth step 506, a second test step 507 is performed to compare the counter value CNT with a second threshold Th2. The second threshold Th2 corresponds to the maximum value of the counter, which represents the maximum energy acceptable to the eye during a given period. While the counter value CNT is less than the second threshold Th2, the fifth step 508 is performed. If the counter value CNT is not less than the second threshold Th2, the sixth step 509 is performed. The fifth step 508 is a waiting process corresponding to the sampling period before the second step 503 is performed again. Typically, a sampling period of 1 microsecond allows for the measurement of a signal with a duration of milliseconds with good accuracy. The sixth step 509 consists of switching the controlled switch 231 off. In the seventh step 510 following the sixth step 509, an alarm signal is transmitted. After the seventh step 510, the program remains in idle step 511 until the next start signal is received. Idle steps 501 and 511 may be the same idle step. Finally, idle step 511 may include a time counter that prevents the system from returning to idle in order to receive a start signal.
[0039] Those skilled in the art will understand that the first and second embodiments perform the same signal processing, one being analog and the other digital. Figures 6 to 9 show time charts corresponding to different use cases of the present invention, with the same signal represented in each figure. The upper time chart represents the value of the current i flowing through the LED light source 22. The counter value CNT is shown in the time chart located in the center. The state value (on-off) of the controlled switch 231 is shown at the bottom.
[0040] Figure 6 corresponds to a typical use case using a constant current illumination period. At time t1, a start signal is received and the controlled switch 231 is switched on. At time t2, the LED driver 21 starts supplying current to the LED light source 22. The counter value CNT increases with each sampling period. At time t3, the LED driver 21 stops supplying current to the LED light source 22. The counter value CNT decreases with each sampling period of decrease value Dec. The counter value CNT reaches a value of 0 at time t4. The LED driver 21 supplies current again at time t5. The counter value CNT increases until time t6 when the LED driver 21 stops supplying current. The counter value CNT decreases from t6 onward. In this embodiment, the counter value never reaches a second threshold Th2. The illumination periods between t2 and t3 and between t5 and t6 never exceed the maximum illumination time, and there is a safe waiting time between the two illumination periods.
[0041] Figure 7 corresponds to a typical use case using illumination periods with current adjustment performed by pulse width modulation. This differs from the previous case in that the illumination periods between t2 and t3 and between t5 and t6 have several current pulses. With each pulse, the counter value CNT increases. Between two pulses, the counter value CNT decreases. During the illumination period, the counter value CNT increases to a value representing the amount of energy released minus the brief decrease period during which the eye was not illuminated. Except for this difference, the time chart is identical to that of Figure 6.
[0042] Figures 8 and 9 illustrate use cases where excessive lighting may occur. Figure 8 illustrates a use case where the lighting period is too long. This can occur if incorrect parameters are entered by the operator in the central unit 1. At time t1, a start signal is received and the controlled switch 231 is switched on. At time t2, the LED driver 21 starts supplying current to the LED light source 22. The counter value CNT increases with each sampling period. At time t3, the counter value reaches a second threshold Th2, and the controlled switch 231 is switched off, simultaneously cutting off the current. The counter value remains at the threshold until a new start signal is received. In this case, the LED circuit breaker 23 stops the lighting period to prevent exceeding the maximum lighting time.
[0043] Figure 9 illustrates a use case where the intervals between illumination periods are insufficient or too many image captures occur consecutively. This use case can occur more frequently than described above, for example, when several illumination periods are triggered consecutively by the automatic setting of camera 3 by the central unit 1 and by a person moving during image capture. In the case of an autonomous system, a person who does not follow instructions may also increase the number of image captures performed by the system. At time t1, the start signal is received and the controlled switch 231 is switched on. At time t2, the LED driver 21 starts supplying current to the LED light source 22. The counter value CNT increases with each sampling period. At time t3, the LED driver 21 stops supplying current to the LED light source 22. The counter value CNT decreases with each sampling period of the decrease value Dec. At time t4, the LED driver 21 resumes supplying current while the counter value has not reached zero. Thus, the counter value CNT increases from a non-zero value. At time t5, the counter value reaches the second threshold Th2, and the controlled switch 231 is switched off, simultaneously cutting off the current. The counter value remains at the threshold until a new start signal is received. The second illumination period, which begins at time t4, is found to be too long considering the pause between time t3 and time t4. If the LED driver 21 terminates the illumination period before the counter value CNT reaches the second threshold Th2, this is within the range of normal use cases. This case may occur after more than two consecutive illumination periods have started before the counter value reaches zero.
[0044] Those skilled in the art will notice that there are decreasing slopes in the dotted lines of Figures 8 and 9. These slopes correspond to the signal values at the output of the integrator 360 corresponding to the counter value CNT. In practice, when the current is cut off, the integrator decreases the voltage V Dec We continue the integration. This is the only difference between the two embodiments.
[0045] For this signal processing, two important values need to be defined, one of which is the reduction voltage V. DecThe first value is Dec, and the other is a second threshold Vth2 or Th2. These values are selected by those skilled in the art, depending on the potential damage to the retina caused by infrared radiation and the characteristics of the LED light source 22. The maximum infrared power received by the eye varies depending on the exposure time. Typically, the eye can tolerate greater infrared power for shorter periods than for longer periods, but the energy that can cause damage (the time integral of power) is smaller for shorter periods than for longer periods. The relationship between the power supplied to the LED light source 22 and the power received by the eye 5 depends on the diffusion angle of the optical aperture of the LED light source 22 and the distance between the LED light source 22 and the eye 5. Generally, the emitted power and exposure time to infrared radiation are not damaging, but in the case of rapid repetition and / or excessive exposure time, they may be damaging. The maximum safe power and safe exposure time should be defined by those skilled in the art. The LED breaker circuit of the present invention only ensures that the exposure time does not exceed the maximum exposure time and that the eye has sufficient rest time before receiving new exposure to IR. The second threshold Th2 may correspond to energy equal to the maximum safe power during the maximum safe exposure period. Next, the reduction value is defined such that the second threshold Th2 decreases to zero at a constant gradient over the maximum rest period. The maximum rest period can be set to a sufficiently long time so that it can be considered that the maximum energy corresponding to the second threshold Th2 can be received again without damage.
[0046] This specification presents an iris scanner that captures images using infrared LEDs. However, the present invention is not limited to iris scanners and can be used in other devices that use LED lighting which may be susceptible to damage. The LED circuit breaker is not limited to use with infrared LEDs and can be used in other LED circuits where excessive light intensity may be dangerous. It can be used with very high-intensity visible light or UV light.
[0047] Furthermore, many other modifications can be made without departing from the claimed invention. For example, in the described embodiment, the alarm signal is transmitted only to the central unit. The central unit may trigger a message or sound. However, the LED circuit breaker may also emit an audio signal and illuminate a visual signal in addition to, or instead of, transmitting an alarm signal to the central unit.
Claims
1. An LED circuit breaker (23) is intended to be installed in series between an LED driver (21) and an LED light source (22), - A controlled switch (231) is installed in series between the LED driver (21) and the LED light source (22) to open and close the circuit. - A sensor (232) that measures the power supplied to the LED light source (22) by the LED driver (21), and provides the measured value. - A control circuit (233) connected to the sensor (232) for receiving the measured value and connected to the switch for controlling the controlled switch (231), wherein the control circuit (233) - To obtain the illumination value (CNT) representing the amount of illumination, the measured value is integrated over time (505), - The illumination value is a predetermined threshold (V Ｔｈ２ An LED circuit breaker (23) is configured to open the controlled switch (231) (509) when the threshold (Th2) is exceeded.
2. The LED circuit breaker according to claim 1, wherein the control circuit (233) is configured to reduce the illumination value (506) when the measured value is equal to zero.
3. The LED circuit breaker according to claim 2, wherein the reduction of the illumination value is performed according to a constant gradient with respect to time.
4. The LED circuit breaker according to any one of claims 1 to 3, wherein the sensor (232) is a current sensor and the measured value is a current measurement value.
5. The LED circuit breaker according to any one of claims 1 to 4, wherein the LED circuit breaker (23) is isolated from the LED driver (21) and the LED light source (22), the controlled switch (231) is of the relay type, and the sensor (232) is a Hall effect sensor.
6. The LED circuit breaker according to any one of claims 1 to 5, wherein the control circuit (233) is configured to be reset by an external action of an operator in order to allow the controlled switch (231) to be closed again after the controlled switch (231) has been opened.
7. An LED circuit comprising an LED driver (21) and at least one LED light source (22) connected to the LED driver (21), wherein the LED circuit includes an LED circuit breaker (23) according to any one of claims 1 to 6.
8. An iris scanner comprising a central unit (1), wherein the central unit (1) is connected to a camera (3), an illuminator (2), and a user interface (4), the central unit (1) is positioned in front of the camera (3) and controls the illuminator (2) and the camera (3) to capture an identification image of the iris (5) illuminated by the illuminator (2), and the illuminator (2) is an LED circuit according to any one of claims 1 to 6.
9. The iris scanner according to claim 8, wherein the camera (3) is an infrared camera and the LED light source (22) comprises an infrared LED.
10. The iris scanner according to claim 8 or 9, wherein the central unit (1) is connected to the control circuit (233) of the LED circuit breaker (23) through an insulating coupler (240), the LED circuit breaker (233) includes an isolated power supply (241) for supplying power to the components of the LED circuit breaker (23), and the isolated power supply (241) is galvanically independent from the power supplies of the LED driver (21), the central unit (1), and the camera (3).