Classifications

• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
  • G02B23/12—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices with means for image conversion or intensification
  • G02B23/125—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices with means for image conversion or intensification head-mounted
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F1/00—Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00
  • G06F1/26—Power supply means, e.g. regulation thereof
  • G06F1/32—Means for saving power
  • G06F1/3203—Power management, i.e. event-based initiation of a power-saving mode
  • G06F1/3206—Monitoring of events, devices or parameters that trigger a change in power modality
  • G06F1/3231—Monitoring the presence, absence or movement of users
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F41—WEAPONS
  • F41G—WEAPON SIGHTS; AIMING
  • F41G1/00—Sighting devices
  • F41G1/32—Night sights, e.g. luminescent

Definitions

• the present invention relates to electronic binoculars.
• the invention is part of electronic binoculars equipped with a microscreen, particularly when used at night.
• binoculars are, for example, light intensifying night vision binoculars or thermal binoculars.
• the microscreen makes it possible to display, in the range of wavelengths visible to the human eye, the image of the optical flow captured by the binoculars' video detector.
• the light emitted by the microscreen is easily visible, particularly when the user moves the binoculars closer to or further from their eyes and this light reflects on their face.
• a first solution consists of turning off the microscreen by pressing a button on the binoculars. This solution is functional, but not automatic.
• Another solution consists of detecting the presence of a user by measuring a pressure difference between the inside and outside of the windshield.
• this involves creating a difference in pressure between the inside and outside of the windshield, which impacts the autonomy and discretion of the binoculars.
• Yet another solution consists of using a mechanical device allowing the diaphragms to be opened by pressing on the eyepiece cups. However, this involves constantly resting the binoculars on the eye sockets. In addition, this solution does not offer the possibility of increasing autonomy by cutting off the microscreen.
• Yet another solution consists of detecting the presence of a user by a vibration and movement sensor. However, this is not compatible with observation on a resting tripod or observation from height downwards (tower or helicopter towards the ground).
• the present description relates to electronic binoculars comprising: an assembly for capturing an optical flow coming from a scene,
• the detection assembly comprising:
• a capacitive sensor positioned so that its capacity fluctuates when a user approaches or moves away from it, said capacity being the sum of a surrounding capacity and a possible capacity relating to the proximity of the user
• a calibration block capable of updating the detection threshold so as to compensate for variations in surrounding capacitance, the calibration block being capable of carrying out the update only in the absence of proximity detected by the detection assembly so that the detection threshold is frozen at its last value during proximity detection, and an assembly for controlling the display of the microscreen as a function of the optical flow captured by the sensing assembly and the detection carried out by the detection assembly so that the microscreen is activated only during proximity detected by the detection assembly.
• electronic binoculars include one or more of the following characteristics, taken in isolation or in all technically possible combinations:
• each eyepiece is formed of a metal body, the capacitive sensor being the metal body of the or at least one of the eyepieces;
• the detection block is capable of detecting proximity as a function of phase variations of a signal internal to the detection block and of the detection threshold, the phase variations being a function of the capacity of the capacitive sensor;
• the detection block includes:
• an oscillator capable of generating a clock signal, called internal signal
• a phase shifter capable of phase shifting the internal signal according to the capacity of the capacitive sensor, to obtain a detection signal
• phase shifter capable of shifting the internal signal in an adjustable manner, to obtain a sampling signal, the reference phase shifter being adjusted as a function of the detection threshold
• a sampler capable of sampling the detection signal from the sampling signal to obtain an output signal, the output signal being capable of taking two states such as:
• the sampler is capable of sampling the detection signal on both fronts of the sampling signal
• the detection block further comprises a double time constant filter capable of validating the output signal indicating detection or not of proximity, only following obtaining a predetermined number of consecutive samplings of the detection signal detection giving an output signal in the same state;
• the detection block comprises a protection module between the capacitive sensor and the detection phase shifter, the protection module being able to filter high frequency radiation and/or to form protection against electrostatic discharges;
• the detection threshold is formed by the sum of a sliding average of the surrounding capacity in the absence of detection and a sensitivity difference
• the sensitivity difference is adjustable by a user so as to adjust the distance from which the detection block detects proximity;
• the calibration block is capable of updating the detection threshold at a predetermined frequency
• - electronic binoculars are light intensifying binoculars or thermal binoculars.
• Figure 1 a schematic representation of an example of electronic binoculars comprising a sensing assembly, a restitution assembly, a detection assembly and a control assembly,
• FIG 2 a schematic representation of an example of an embodiment of the electronic binoculars of Figure 1
• FIG 3 a schematic representation of another example of an embodiment of the electronic binoculars of Figure 1
• Figure 4 a schematic representation of an exemplary embodiment of the detection assembly of Figure 1
• Figure 5 a schematic representation of an example of the detection threshold updated by the calibration block depending on whether or not a proximity is detected.
• the electronic binoculars 10 are, for example, light intensifying binoculars or thermal binoculars.
• Electronic binoculars 10 are any type of binoculars, including monocular binoculars, bioocular binoculars, binocular binoculars or even panoramic binoculars (4-way intensified).
• the binoculars 10 comprise a collection assembly 12, a restitution assembly 14, a detection assembly 16 and a control assembly 18.
• the collection assembly 12, the restitution assembly 14 and the The detection assembly 16 are all three connected to the control assembly 18 to exchange information with this control assembly 18.
• the capture assembly 12 is capable of capturing an optical flow coming from a scene.
• the capture assembly 12 comprises at least one objective 30 and a sensor 32.
• the objective 30 is capable of focusing an optical flow, coming from the observed scene, on the sensor 32.
• the sensor 32 is sensitive to the range of wavelengths observed (visible, infrared).
• the restitution assembly 14 is capable of restoring the optical flow captured in a range of wavelengths visible to a user.
• the restitution assembly 14 includes a microscreen 34 and at least one eyepiece 36.
• the microscreen 34 is capable of displaying an image as a function of the optical flow captured, the displayed image being in a range of wavelengths visible to the user (visible). Each eyepiece 36 allows the user to view the image displayed by the microscreen 34.
• the restitution assembly 14 comprises two eyepieces 36.
• Each eyepiece 36 is, for example, associated with a combination of optics 38 making it possible to return the image projected by the microscreen 34 on the eyepiece 36. This is particularly the case in the examples of Figures 2 and 3.
• the restitution assembly 14 comprises a single eyepiece 36.
• the image of the microscreen 34 is, for example, projected directly onto the eyepiece 36.
• each eyepiece 36 comprises optics contained in a metal body, such as a metal tube.
• the metal body is insulated from the binoculars 10 EMC (electromagnetic compatibility) shielding.
• the binoculars 10 also include a portable power source 40 and a user interface 42.
• the portable power source 40 is, for example, a battery or a rechargeable cell.
• the user interface 42 allows a user to make choices among the software menus of the binoculars 10.
• the user interface 42 includes, for example, one or more push buttons and/or a joystick.
• the detection assembly 16 is capable of detecting the proximity of a user in relation to at least one of the eyepieces 36 (the proximity is counted in relation to the eyepieces 36, because it is they which transmit the light from the microscreen and involuntarily illuminate the user's face).
• the detection assembly 16 is capable of detecting the proximity of an element (user) located at a distance less than a predetermined distance from or at least one of the eyepieces 36.
• the predetermined distance is, for example example, equal to zero, which means that proximity is detected when the user has his face against the eyepieces 36.
• the predetermined distance is, for example, equal to a few centimeters (for example 10 centimeters), which means that proximity is detected as soon as the user has his face close to the eyepieces 36.
• the predetermined distance depends on a predetermined sensitivity difference (offset), and is possibly adjustable by a user.
• the detection assembly 16 includes a capacitive sensor 50, a detection block 52 and a calibration block 54.
• the capacitive sensor 50 is a proximity sensor.
• the capacitive sensor 50 comprises a metallic element forming a capacitor with the user (the human body being a conductor). At least one measuring electrode makes it possible to measure the capacitance of the capacitor thus formed.
• the capacitive sensor 50 operates at low frequency where the EMC radiation constraints are very low (less than 100kHz, but greater than 20kHz to avoid any audible noise by piezoelectric effect).
• the capacitive sensor 50 thus presents multiple advantages:
• the capacitive sensor 50 is positioned in the electronic binoculars 10 so that its capacitance fluctuates when a user approaches or moves away from it (in particular approaches or moves away from an eyepiece 36). More precisely, the capacity of the capacitive sensor 50 is the sum of a surrounding capacity (relative to its environment), and a possible capacity relating to the proximity between a user and this sensor 50.
• the capacitive sensor 50 is the metal body of the or at least one of the eyepieces 36. This avoids adding a specific sensor on the rear face, which simplifies the mechanical design of the binoculars 10.
• This example corresponds in particular to the embodiment of Figure 2.
• the metal body has been isolated from the EMC (electromagnetic compatibility) shielding of the binoculars 10.
• the capacitive sensor 50 is a dedicated sensor, different from the eyepieces 36.
• the capacitive sensor 50 is, for example, an armored metal plate. This variant corresponds in particular to the embodiment of Figure 3.
• the detection block 52 is capable of detecting the proximity of a user to at least one of the eyepieces 36, depending on the capacity of the capacitive sensor 50 and a detection threshold.
• the detection block 52 is capable of detecting the proximity of a user as a function of phase variations of a signal internal to the detection block 52 and of the detection threshold. Phase variations are a function of the sensor capacity capacitive 50. Taking into account phase variations of an internal signal makes detection robust to EMC attacks. Indeed, an external, and therefore independent, signal cannot have exactly the same phase as an internal signal.
• the detection block 52 comprises an oscillator 60, a first phase shifter, called detection phase shifter 62, a second phase shifter, called reference phase shifter 64, and a sampler 66.
• Oscillator 60 is capable of generating a clock signal, called internal signal CLK.
• Oscillator 60 operates at low frequency where EMC radiation constraints are very low (less than 100kHz, but greater than 20kHz to avoid any audible noise by piezoelectric effect).
• the frequency of the oscillator is, for example, equal to 30 kHz.
• the detection phase shifter 62 is able to phase shift the internal signal CLK as a function of the capacity of the capacitive sensor 50, to obtain a detection signal SENSE.
• the phase shift of the signal coming from the detection phase shifter 62 increases when the capacity sensed by the capacitive sensor 50 increases (and therefore increases when the user approaches the sensor).
• the detection phase shifter 62 is formed from the capacitance of the capacitive sensor 50, a series resistor and a reshaping stage (reshaping of the signal).
• the reference phase shifter 64 is able to phase shift the internal signal CLK in an adjustable manner, to obtain a sampling signal DCLK.
• the adjustment of the reference phase shifter 64 is carried out in particular as a function of the detection threshold.
• the reference phase shifter 64 is formed of a capacitor, a series resistor and a signal reshaping stage. At least one of these elements is variable, for example the resistance (so that the reference phase shifter 64 is adjustable).
• the reference phase shifter 64 is adjusted so that the phase of the sampling signal DLCK is slightly greater than that of the detection signal SENSE, outside of user proximity.
• the phase difference between the two is a sensitivity offset for proximity detection.
• the sensitivity offset thus fixes the predetermined distance between the user and the eyepieces 36, from which proximity detection is carried out.
• the phase shift of the detection signal SENSE increases until it exceeds that of the sampling signal DLCK (see timing diagram in Figure 4, period P2).
• the phase shift variation of the SENSE detection signal increases until it exceeds the sensitivity offset.
• the sampler 66 is capable of sampling the detection signal SENSE from the sampling signal DCLK, to obtain an output signal Q.
• the output signal Q is capable of taking two states such as:
• the output signal Q is in a second state, indicating proximity detection.
• the sampler 66 is made with at least one D flip-flop.
• the sampler 66 is capable of sampling the detection signal SENSE on the two fronts (at 0° and 180°) of the sampling signal DCLK.
• the detection block 52 further comprises a filter 68 with a double time constant.
• the filter 68 is capable of validating the output signal Q of the detection block 52 indicating detection or not of proximity, only following obtaining an output signal Q in the same state over a predetermined duration, which corresponds to a predetermined number of consecutive samplings, carried out by the sampler 66, in the same state.
• proximity detection is validated only if several consecutive samples of the detection signal SENSE, corresponding to the output signal Q in the second state, are obtained.
• the detection signal SENSE indeed comes from the internal signal CLK of the oscillator 60
• the signals SENSE and DCLK have the same frequency and the two samplings in phase opposition of the sampler 66 always have complementary logic levels. If, on the contrary, the SENSE detection signal is disturbed by an EMC attack seeking to simulate the presence of the user, the two samplings in phase opposition cannot remain at complementary levels in the long term, because the EMC attack is external to the system and cannot be correlated with the phase of oscillator 60.
• the filter 68 with double time constant makes it possible to confirm the detection, in particular after a large number of sampling pairs (07180°) in the same state and consecutively.
• the consecutive aspect is obtained, on the one hand, thanks to the constant of “large” time which makes it possible to achieve the large number of samplings in the same state, and, on the other hand, thanks to the “small” time constant which makes it possible to reset the state of the filter 68 as soon as a sampling pair 07180° does not present complementary logic levels.
• the “large” time constant is chosen to be both large compared to the period of oscillator 60, and at the same time small enough not to introduce any significant delay on a human scale when the user brings his face closer to the capacitive sensor. 50.
• the “large” time constant is, for example, equal to 1000 periods of oscillator 60, or 30 ms.
• the detection block 52 also includes a protection module 70 between the capacitive sensor 50 and the detection phase shifter 62.
• the protection module 70 is capable of filtering high frequency radiation (both internal and external) and/or or to form protection against electrostatic discharge (ESD protection). ESD protection is useful since the capacitive sensor 50 is a conductive part accessible outside the binoculars 10 and electrically connected to the inside of the binoculars 10.
• the calibration block 54 is capable of updating the detection threshold so as to compensate for variations in surrounding capacitance.
• the variations in surrounding capacitance are, for example, due to variations in the dielectric permittivity of the air as a function of pressure, temperature and humidity, but also to variations in the mechanical dimension of the materials of the eyepieces 36 and of the body of binoculars 10 due to dilation.
• the calibration block 54 is capable of carrying out the update only in the absence of proximity detected by the detection assembly 16 so that the detection threshold is frozen at its last value during a proximity detection.
• the calibration block 54 takes proximity detections into account to stop the calibrations and not compensate for a variation in capacity by proximity. This is made possible because variations in surrounding capacitance are very small during normal viewing times through binoculars.
• the detection threshold is therefore adjusted, by the calibration block 54, as a function of the surrounding capacitance and in the absence of a user near the eyepiece 36. This makes it possible to compensate for variations in surrounding capacitance.
• the calibration block 54 uses a calibration algorithm which measures the surrounding capacitance and forms the detection threshold by the sum of a sliding average of this surrounding capacitance (in the absence of detection) and a sensitivity offset (concept mentioned above in the context of the example of realization of the detection block 52).
• the sensitivity offset is, for example, adjustable by a user so as to adjust the distance from which the detection block 52 detects proximity.
• the calibration block 54 is capable of updating the detection threshold, not continuously, but at a predetermined frequency.
• the predetermined frequency is chosen so as to constitute an activation rate of the calibration algorithm much faster than the variations in surrounding capacitance and, thus, at each iteration, the quantity of variation in surrounding capacitance to be compensated is very small.
• the predetermined frequency can , for example, be chosen once every 10s.
• the maximum temperature variation at each iteration of the calibration algorithm is 0.5°C, or 1.07 LSB (Least Significant Bit) of the range to be compensated. It is therefore possible, for example, to limit the compensations of the calibration algorithm to 2 LSB maximum at each iteration.
• the calibration block 54 is clocked by a sequencer which activates the calibration algorithm at the desired rate.
• This algorithm makes it possible to form the detection threshold by following long-term variations of the capacitive signal (typically T2: slow variation of the surrounding capacitance over several tens of minutes).
• the detection sensitivity is configured by the offset introduced between the capacitive signal, excluding user proximity detections, and the detection threshold.
• the calibration algorithm takes proximity detections into account (T 1: short proximity, a few seconds; T3: long proximity, a few minutes) and, in this case, stops the calibrations so as not to compensate for a variation in capacitance by proximity, which implies a detection threshold locked at its last value.
• the detection threshold corresponds to the setting of the reference phase shifter 64.
• the calibration block 54 uses the internal signal CLK of the oscillator 60 to synchronize the application of corrections to the reference phase shifter 64, as well as the output signal Q of the sampler 66 to determine whether to increase or decrease the phase shift of the reference phase shifter 64 during the calibration phases.
• the calibration block 54 is capable of communicating with the control assembly 18 (main electronics of the binoculars 10) via a control/command link (typically a serial link).
• a control/command link typically a serial link.
• This link makes it possible to exchange information relating to the calibration, and makes it possible to configure the sensitivity of the detection block 52.
• the proximity information of the user's face can, for its part, be sent to the control assembly. 18 either by this serial link, or by a specific interrupt signal.
• the control assembly 18 is capable of controlling the display of the microscreen 34 as a function of the optical flow captured by the sensing assembly 12 and the detection carried out by the detection assembly 16.
• the control assembly 18 is capable of activating the microscreen 34 (the lighting of the microscreen 34) only when proximity detection has been carried out by the detection assembly 16.
• the detection assembly 16 provides the proximity information of the user's face to the control assembly 18 (main electronics of the binoculars 10).
• the control assembly 18 uses or not this information to control the lighting of the microscreen 34 depending on the software configuration.
• control assembly 18 is also capable of carrying out the formatting of the information coming from the image sensor 32, the video processing and the execution of the software of the binoculars 10, as well as the formatting of video information to the microscreen 34.
• the capacity of the capacitive sensor 50 results only from the environment.
• the detection signals SENSE and reference signals DCLK are out of phase so that the phase of the detection signal SENSE is less than the phase of the sampling signal DCLK.
• the phase shift of the SENSE detection signal is in this case only due to surrounding capacity.
• the sampling of the detection signal SENSE by the sampling signal DCLK is such that the output signal Q of the sampler 66 is in the first state. This is particularly visible in the chronogram in Figure 4 (period P1, the first state corresponds to the high state).
• This absence of proximity detection is communicated by the detection assembly 16 to the control assembly 18, thus allowing the control assembly 18 to keep the microscreen 34 inactive, or to deactivate it if it was on.
• the phase of the detection signal SENSE is greater than the phase of the sampling signal DCLK. Indeed, the phase shift of the SENSE detection signal is in this case due to the surrounding capacitance and in addition to an added capacitance due to the presence of the user.
• the sampling of the detection signal SENSE by the sampling signal DCLK is such that the output signal Q of the sampler 66 is in the second state. This is particularly visible in the chronogram in Figure 4 (period P2, the second state corresponds to the low state).
• the change of state is validated by filter 68 with double time constant (OUT signal) only after a period of time P3.
• the period P3 is, for example, equal to 30 ms.
• This proximity detection is communicated by the detection assembly 16 to the control assembly 18, thus allowing the control assembly 18 to activate the microscreen 34 or to continue to keep it active.
• the detection assembly 16 makes it possible to detect the proximity of a user in relation to one of the eyepieces 36 of the binoculars 10. This allows the control assembly 18 to automatically turn off the microscreen 34 of the binoculars 10 as soon as that the user moves his face away from the binoculars 10 (or his eyes from the eyepieces 36), so that the light from the microscreen 34 is not reflected on his face, which would make him very easy to spot in the middle of the night. Such a function also makes it possible to optimize the consumption of the binoculars 10 by eliminating that of the microscreen 34 each time the user moves his eyes away.
• Freezing the detection threshold at its last value once a proximity is detected allows detection of both long proximities and short proximities, without detection error at the start or end of these proximities.
• Capacitive proximity detection also has the advantage of being discreet: no visible, near infrared (PIR) or infrared radiation, and very low electromagnetic radiation.
• PIR near infrared
• Capacitive proximity detection also has the advantage of being discreet: no visible, near infrared (PIR) or infrared radiation, and very low electromagnetic radiation.

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• General Engineering & Computer Science (AREA)
• Astronomy & Astrophysics (AREA)
• Optics & Photonics (AREA)
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• 2022
  • 2022-12-30 FR FR2214699A patent/FR3144673A1/fr active Pending
• 2023
  • 2023-12-28 WO PCT/EP2023/087906 patent/WO2024141591A1/fr not_active Ceased
  • 2023-12-28 EP EP23838141.2A patent/EP4643170A1/de active Pending

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