Electronic binoculars
Patent Information
- Application Number
- EP2023838141
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-12-30
- Filing Date
- 2023-12-28
- Publication Date
- 2025-11-05
AI Technical Summary
Existing electronic binoculars with microscreens, such as night vision or thermal binoculars, face challenges in automatically turning off the microscreen when the user moves the binoculars away from their face, particularly in military contexts, where previous solutions like infrared detection illuminate the user and impact autonomy or require constant resting on the eye sockets.
The implementation of a capacitive sensor integrated into the eyepiece, which detects proximity by fluctuating capacitance, combined with a detection block and calibration block, automatically controls the microscreen activation only when the user is detected close to the eyepiece, using phase variations and adjustable detection thresholds to ensure accurate and discreet operation.
This solution allows for automatic and discreet activation of the microscreen only during user proximity, optimizing power consumption and preventing light reflection on the user's face, enhancing usability and autonomy in military contexts.
Smart Images
Figure 1.1
Abstract
Description
[0001] TITLE: Electronic Binoculars
[0002] The present invention relates to electronic binoculars.
[0003] More specifically, the invention relates to electronic binoculars equipped with a microscreen, particularly for use at night. Such binoculars are, for example, light-intensified night vision binoculars or thermal binoculars. The microscreen makes it possible to display, in the wavelength range visible to the human eye, the image of the optical flow captured by the video detector of the binoculars.
[0004] However, when used at night, the light emitted by the microscreen is easily noticeable, especially when the user moves the binoculars closer to or further from their eyes and this light reflects on their face.
[0005] Various solutions are known from the state of the art for turning off the microscreen when the binoculars are not in use.
[0006] In particular, a first solution is to turn off the microscreen by pressing a button on the binoculars. This solution is functional, but not automatic.
[0007] It is also known to detect the user's presence using an infrared (IR) transmitter and receiver on the binoculars. This allows for automatic control of the binoculars. However, this solution is not usable in military environments because the IR transmitter illuminates the user's face just as much, or even more, than the microscreen.
[0008] Another solution is to detect the presence of a user by measuring a pressure difference between the inside and outside of the lens. However, this involves creating a pressure difference between the inside and outside of the lens, which impacts the autonomy and discretion of the binoculars.
[0009] Yet another solution is to use a mechanical device that allows the diaphragms to be opened by pressing on the eyepiece cups. However, this involves constantly pressing the binoculars against the eye sockets. In addition, this solution does not offer the possibility of increasing the autonomy by turning off the microscreen.
[0010] Yet another solution is to detect the presence of a user by a vibration and movement sensor. However, this is not compatible with observation on a tripod or observation from above (tower or helicopter towards the ground).
[0011] There is therefore a need for a means of automatically turning off the microscreen of electronic binoculars as soon as the user moves the binoculars away from his face, in all circumstances, particularly in a military context, and while being easy to use.
[0012] For this purpose, the present description relates to electronic binoculars comprising: a set for capturing an optical flow coming from a scene,
[0013] - a set for restoring the captured optical flow including:
[0014] • a microscreen capable of displaying an image based on the captured optical flow, and
[0015] • at least one eyepiece for viewing the image displayed by the microscreen,
[0016] - an assembly for detecting the proximity of a user relative to at least one eyepiece, the detection assembly comprising:
[0017] • a capacitive sensor positioned so that its capacitance fluctuates when a user approaches or moves away from it, said capacitance being the sum of a surrounding capacitance and a possible capacitance relative to the proximity of the user,
[0018] • a block for detecting the proximity of a user to at least one eyepiece as a function of the capacity of the capacitive sensor and a detection threshold, the detection threshold being set as a function of the surrounding capacity in the absence of detected proximity, and
[0019] • a calibration block capable of updating the detection threshold so as to compensate for variations in surrounding capacity, 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 fixed at its last value during proximity detection, and a set for controlling the display of the microscreen as a function of the optical flow captured by the capture assembly and the detection carried out by the detection assembly so that the microscreen is activated only during proximity detected by the detection assembly.
[0020] According to particular embodiments, the electronic binoculars comprise one or more of the following characteristics, taken in isolation or in all technically possible combinations:
[0021] - each eyepiece is formed of a metal body, the capacitive sensor being the metal body of the or at least one of the eyepieces;
[0022] - the detection block is capable of detecting proximity as a function of the phase variations of a signal internal to the detection block and of the detection threshold, the phase variations being a function of the capacitance of the capacitive sensor;
[0023] - the detection block includes:
[0024] - an oscillator capable of generating a clock signal, called an internal signal, - a phase shifter, called a detection phase shifter, capable of shifting the internal signal according to the capacitance of the capacitive sensor, to obtain a detection signal,
[0025] - a phase shifter, called a reference phase shifter, capable of shifting the internal signal in an adjustable manner, to obtain a sampling signal, the reference phase shifter being adjusted according to the detection threshold,
[0026] - a sampler suitable for sampling the detection signal from the sampling signal to obtain an output signal, the output signal being suitable for taking two states such that:
[0027] • when the phase of the detection signal is lower than that of the sampling signal, the output signal is in a first state, indicating an absence of detected proximity, and
[0028] • when the phase of the detection signal is greater than that of the sampling signal, the output signal is in a second state, indicating proximity detection;
[0029] - the sampler is suitable for sampling the detection signal on both edges of the sampling signal;
[0030] - the detection block further comprises a double time constant filter suitable for validating the output signal indicating proximity detection or not, only after obtaining a predetermined number of consecutive samples of the detection signal giving an output signal in the same state;
[0031] - the detection block comprises a protection module between the capacitive sensor and the detection phase shifter, the protection module being capable of filtering high-frequency radiation and / or of forming protection against electrostatic discharges;
[0032] - the detection threshold is formed by the sum of a sliding average of the surrounding capacity in the absence of detection and a sensitivity deviation;
[0033] - the sensitivity gap is adjustable by a user so as to adjust the distance from which the detection block detects proximity;
[0034] - the calibration block is capable of updating the detection threshold at a predetermined frequency;
[0035] - electronic binoculars are light-intensifying binoculars or thermal binoculars.
[0036] Other characteristics and advantages of the invention will appear on reading the following description of the embodiments of the invention, given by way of example only and with reference to the drawings which are: Figure 1, a schematic representation of an example of electronic binoculars comprising a capture assembly, a restitution assembly, a detection assembly and a control assembly,
[0037] Figure 2, a schematic representation of an example of an embodiment of the electronic binoculars of Figure 1,
[0038] Figure 3, a schematic representation of another example of an embodiment of the electronic binoculars of Figure 1,
[0039] Figure 4, a schematic representation of an exemplary embodiment of the detection assembly of Figure 1, and
[0040] Figure 5, a schematic representation of an example of the detection threshold updated by the calibration block depending on whether or not proximity is detected.
[0041] An example of electronic binoculars 10 is schematically illustrated in Figure 1. More specific embodiments are illustrated in Figures 2 and 3.
[0042] Electronic binoculars 10 are, for example, light-intensifying binoculars or thermal binoculars. Electronic binoculars 10 are any type of binoculars, including monocular binoculars, biocular binoculars, binocular binoculars or panoramic binoculars (4-way intensified).
[0043] As seen in Figure 1, the binoculars 10 comprise a capture assembly 12, a restitution assembly 14, a detection assembly 16 and a control assembly 18. The capture assembly 12, the restitution assembly 14 and the detection assembly 16 are all three connected to the control assembly 18 to exchange information with this control assembly 18.
[0044] The capture assembly 12 is capable of capturing an optical flow coming from a scene.
[0045] As illustrated by the examples of figures 2 and 3, the capture assembly 12 comprises at least one lens 30 and one sensor 32. The lens 30 is capable of focusing an optical flow, coming from the observed scene, onto the sensor 32. The sensor 32 is sensitive to the range of wavelengths observed (visible, infrared).
[0046] The restitution assembly 14 is capable of restoring the optical flow captured in a range of wavelengths visible to a user.
[0047] The restitution assembly 14 comprises a microscreen 34 and at least one eyepiece 36.
[0048] The microscreen 34 is capable of displaying an image as a function of the captured optical flow, 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.
[0049] In the case of biocular, binocular, or panoramic binoculars, 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 onto the eyepiece 36. This is particularly the case in the examples of figures 2 and 3.
[0050] In the case of a monocular, the restitution assembly 14 comprises a single eyepiece 36. In this case, the image of the microscreen 34 is, for example, projected directly onto the eyepiece 36.
[0051] In one exemplary implementation, each eyepiece 36 includes optics contained within a metal body, such as a metal tube. The metal body is insulated from the EMC (electromagnetic compatibility) shielding of the binoculars 10.
[0052] Preferably, as illustrated by the embodiments of Figures 2 and 3, the binoculars 10 also include a portable power source 40 and a user interface 42.
[0053] The portable power source 40 is, for example, a battery or a rechargeable battery.
[0054] The user interface 42 allows a user to make choices from software menus of the binoculars 10. The user interface 42 includes, for example, one or more push buttons and / or a joystick.
[0055] The detection assembly 16 is capable of detecting the proximity of a user relative to at least one of the eyepieces 36 (the proximity is counted relative to the eyepieces 36, since they are the ones that transmit the light from the microscreen and involuntarily illuminate the user's face). In particular, the detection assembly 16 is capable of detecting a 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, equal to zero, which means that a proximity is detected when the user has his face against the eyepieces 36. Alternatively, the predetermined distance is, for example, equal to a few centimeters (for example 10 centimeters), which means that a proximity is detected as soon as the user has his face close to the eyepieces 36.As will be described in the remainder of the description, the predetermined distance depends on a predetermined sensitivity offset, and is optionally adjustable by a user.
[0056] The detection assembly 16 comprises 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 conductive). At least one measuring electrode makes it possible to measure the capacitance of the capacitor thus formed.
[0057] The 50 capacitive sensor operates at low frequencies where EMC radiation constraints are very low (less than 100kHz, but greater than 20kHz to avoid any audible noise due to piezoelectric effect).
[0058] The 50 capacitive sensor thus presents multiple advantages:
[0059] - an area of application adapted to short distances,
[0060] - great discretion: no visible, near IR (NIR) or IR radiation; very low electromagnetic radiation (this being due to the presence of a variable signal on the capacitive electrodes) limited to Megahertz, considering that the radiation is negligible beyond the 10th harmonic of the operating frequency (to be moderated even more in the examples of figures 2 and 3, by the fact that the position of the sensor 50 makes this radiation directional towards the user during observation),
[0061] - very low consumption, making it possible to optimize the consumption of the binoculars by turning off the microscreen 34.
[0062] The capacitive sensor 50 is positioned in the electronic binoculars 10 such 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 capacitance of the capacitive sensor 50 is the sum of a surrounding capacitance (relating to its environment), and a possible capacitance relating to the proximity between a user and this sensor 50.
[0063] Preferably, 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 FIG. 2. In this case, the metal body has been well isolated from the EMC (electromagnetic compatibility) shielding of the binoculars 10.
[0064] Alternatively, the capacitive sensor 50 is a dedicated sensor, different from the eyepieces 36. The capacitive sensor 50 is, for example, a shielded metal plate. This variant corresponds in particular to the embodiment of FIG. 3.
[0065] The detection block 52 is capable of detecting the proximity of a user relative to at least one of the eyepieces 36, depending on the capacity of the capacitive sensor 50 and a detection threshold.
[0066] Preferably, the detection block 52 is capable of detecting the proximity of a user as a function of the phase variations of a signal internal to the detection block 52 and the detection threshold. The phase variations are a function of the capacitance of the capacitive sensor 50. Taking into account the phase variations of an internal signal makes it possible to make the detection robust to EMC attacks. Indeed, an external, and therefore independent, signal cannot have exactly the same phase as an internal signal.
[0067] In the following, we describe a preferred means of implementing the detection block 52.
[0068] In particular, in an exemplary embodiment illustrated in FIG. 4, the detection block 52 comprises an oscillator 60, a first phase shifter, called the detection phase shifter 62, a second phase shifter, called the reference phase shifter 64, and a sampler 66.
[0069] Oscillator 60 is capable of generating a clock signal, called the internal signal CLK.
[0070] Oscillator 60 operates at low frequencies where EMC radiation constraints are very low (less than 100kHz, but greater than 20kHz to avoid any audible noise due to piezoelectric effect). The oscillator frequency is, for example, equal to 30 kHz.
[0071] The detection phase shifter 62 is capable of phase shifting the internal signal CLK according to the capacitance of the capacitive sensor 50, to obtain a detection signal SENSE. In the embodiment of FIG. 4, the phase shift of the signal from the detection phase shifter 62 increases when the capacitance sensed by the capacitive sensor 50 increases (and therefore increases when the user approaches the sensor).
[0072] In an exemplary implementation, the detection phase shifter 62 is formed from the capacitance of the capacitive sensor 50, a series resistor and a reshaping stage (signal reshaping).
[0073] The reference phase shifter 64 is capable of shifting 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.
[0074] In an exemplary implementation, 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 resistor (so that the reference phase shifter 64 is adjustable).
[0075] The reference phase shifter 64 is adjusted so that the phase of the DLCK sampling signal is slightly greater than that of the SENSE detection signal, outside of user proximities. 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 performed. When the capacitance sensed by the capacitive sensor 50 increases due to a user approaching their face, the phase shift of the SENSE detection signal increases until it exceeds that of the DLCK sampling signal (see timing diagram of FIG. 4, period P2). Or, put another way, when a user approaches their face, the variation in phase shift of the SENSE detection signal increases until it exceeds the sensitivity offset.
[0076] The sampler 66 is suitable for sampling the detection signal SENSE from the sampling signal DCLK, to obtain an output signal Q. The output signal Q is suitable for taking two states such that:
[0077] - when the phase of the detection signal SENSE is lower than that of the sampling signal DCLK, the output signal Q is in a first state, indicating an absence of detected proximity, and
[0078] - when the phase of the SENSE detection signal is greater than that of the DCLK sampling signal, the output signal Q is in a second state, indicating proximity detection.
[0079] For example, sampler 66 is implemented with at least one D flip-flop.
[0080] Preferably, the sampler 66 is capable of sampling the detection signal SENSE on both edges (at 0° and 180°) of the sampling signal DCLK.
[0081] Preferably, 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 a proximity detection or not, only following the obtaining of 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. Thus, a proximity detection is validated only if several consecutive samples of the SENSE detection signal, corresponding to the output signal Q in the second state, are obtained.
[0082] These two aspects ensure robustness to EMC attacks. Indeed, if the SENSE detection signal comes from the internal CLK signal of the oscillator 60, the SENSE and DCLK signals have the same frequency and the two phase-opposed samplings 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 phase-opposed samplings cannot remain at complementary levels in the long term, because the EMC attack is external to the system and cannot be correlated to the phase of the oscillator 60.
[0083] The double time constant filter 68 makes it possible to confirm the detection, in particular after a large number of sampling pairs (07180°) in the same state and consecutive. The consecutive aspect is obtained, on the one hand, thanks to the “large” time constant 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 pair of 07180° samplings does not have complementary logic levels. The “large” time constant is chosen to be both large compared to the period of the oscillator 60, and at the same time sufficiently small so as not to introduce a noticeable delay on a human scale when the user brings his face close to the capacitive sensor 50. The “large” time constant is, for example, equal to 1000 periods of the oscillator 60, or 30 ms.
[0084] Preferably, the detection block 52 also comprises 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 of forming protection against electrostatic discharges (ESD protection). The ESD protection is useful since the capacitive sensor 50 is a conductive part accessible outside the binoculars 10 and electrically connected inside the binoculars 10.
[0085] We will now describe the calibration block 54 in the following.
[0086] 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 variations in the mechanical dimension of the materials of the eyepieces 36 and the body of the binoculars 10 due to expansion.
[0087] The calibration block 54 is capable of performing the update only in the absence of proximity detected by the detection assembly 16 so that the detection threshold is fixed at its last value during a proximity detection. Thus, the calibration block 54 takes into account proximity detections to stop the calibrations and not compensate for a variation in capacity by proximity. This is made possible by the fact that the variations in surrounding capacity are very small during normal observation times through the binoculars.
[0088] The detection threshold is therefore adjusted, by the calibration block 54, according to the surrounding capacity and in the absence of a user near the eyepiece 36. This makes it possible to compensate for variations in surrounding capacity.
[0089] In an exemplary implementation, the calibration block 54 uses a calibration algorithm that 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 (notion mentioned above in the context of the exemplary embodiment 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.
[0090] Preferably, 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 so that, at each iteration, the quantity of variation in surrounding capacitance to be compensated is very low. For example, if one seeks to compensate for variations in surrounding capacitance due to temperature variations at a maximum speed of 3°C / min over a range of + / - 60°C, with a resolution of 8 bits, the predetermined frequency can, for example, be chosen at 1 time every 10s. In this example, and with this choice of predetermined frequency, the maximum variation in temperature 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 a maximum of 2 LSB at each iteration.
[0091] This brings two advantages:
[0092] - on the one hand, this allows for a very short calibration time, which makes it very unlikely that a calibration will start exactly at the same time as a proximity detection,
[0093] - on the other hand, if a calibration starts exactly at the same time as a proximity detection (one and only one calibration since they are then blocked as long as a proximity is detected), the correction made to the detection threshold, due to the application of a calibration while the user is nearby, is very small and does not significantly affect the sensitivity setting. In addition, the delay that the calibration causes while the user wants to use the binoculars is very short and insensitive on a human scale.
[0094] In particular, as visible in Figure 5, 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 the 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 into account proximity detections (T1: brief 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 to its last value.
[0095] In the example embodiment of the detection block 52 detailed previously, the detection threshold corresponds to the setting of the reference phase shifter 64.
[0096] In an exemplary embodiment of the calibration block 54, it 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.
[0097] Preferably, 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). 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 via this serial link or via a specific interrupt signal.
[0098] The control assembly 18 is capable of controlling the display of the microscreen 34 as a function of the optical flow captured by the capture assembly 12 and the detection carried out by the detection assembly 16. In particular, the control assembly 18 is capable of activating the microscreen 34 (the lighting of the microscreen 34) only when a proximity detection has been carried out by the detection assembly 16.
[0099] Thus, 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 this information or not to control the lighting of the microscreen 34 depending on the software configuration.
[0100] In particular, the control assembly 18 is also capable of carrying out the formatting of the information from the image sensor 32, the video processing and the execution of the software of the binoculars 10, as well as the formatting of the video information to the microscreen 34.
[0101] An example of the operation of the binoculars 10 will now be described, particularly in the context of proximity detection.
[0102] In the absence of proximity of a user with respect to the eyepiece 36, the capacitance of the capacitive sensor 50 results only from the environment. As visible in FIG. 4, the detection signals SENSE and reference DCLK are phase-shifted so that the phase of the detection signal SENSE is less than the phase of the sampling signal DCLK. Indeed, the phase shift of the detection signal SENSE is in this case only due to the surrounding capacitance. 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 notably visible on the timing diagram of FIG. 4 (period P1, the first state corresponds to the high state).
[0103] This lack 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.
[0104] During proximity detection, the phase of the SENSE detection signal is greater than the phase of the DCLK sampling signal. In fact, 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 SENSE detection signal by the DCLK sampling signal is such that the output signal Q of the sampler 66 is in the second state. This is particularly visible on the timing diagram of Figure 4 (period P2, the second state corresponds to the low state). The change of state is validated by the filter 68 with double time constant (OUT signal) only after a time period P3. The period P3 is, for example, equal to 30 ms.
[0105] This proximity detection is communicated by the detection assembly 16 to the control assembly 18, thereby enabling the control assembly 18 to activate the microscreen 34 or continue to keep it active.
[0106] Thus, the detection assembly 16 makes it possible to detect the proximity of a user 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 the user moves his face away from the binoculars 10 (or his eyes away from the eyepieces 36), so that the light from the microscreen 34 is not reflected on his face, which would make him very easily spotted 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.
[0107] Freezing the detection threshold at its last value once a proximity has been detected allows detection of both long and short proximities, without detection errors at the start or end of these proximities.
[0108] Capacitive proximity detection also has the advantage of being discreet: no visible, near infrared (NIR) or infrared radiation, and very low electromagnetic radiation. Those skilled in the art will understand that the embodiments and variants previously described can be combined with each other provided that they are technically compatible.
Claims
CLAIMS 1. Electronic binoculars (10) comprising: a collection assembly (12) for capturing an optical flow coming from a scene, - a set (14) for restoring the captured optical flow comprising: • a microscreen (34) capable of displaying an image based on the captured optical flow, and • at least one eyepiece (36) for viewing the image displayed by the microscreen (34), - a detection assembly (16) for detecting the proximity of a user relative to at least one eyepiece (36), the detection assembly (16) comprising: • a capacitive sensor (50) positioned so that its capacitance fluctuates when a user approaches or moves away from it, said capacitance being the sum of a surrounding capacitance and a possible capacitance relating to the proximity of the user, • a detection block (52) for detecting the proximity of a user relative to at least one eyepiece (36) as a function of the capacity of the capacitive sensor (50) and a detection threshold, the detection threshold being set as a function of the surrounding capacity in the absence of detected proximity, and • a calibration block (54) capable of updating the detection threshold so as to compensate for variations in surrounding capacity, the calibration block (54) being capable of carrying out the update only in the absence of proximity detected by the detection assembly (16) so that the detection threshold is fixed at its last value during a proximity detection, and a control assembly (18) for the display of the microscreen (34) as a function of the optical flow captured by the capture assembly (12) and of the detection carried out by the detection assembly (16) so that the microscreen (34) is activated only during a proximity detected by the detection assembly (16).
2. Electronic binoculars (10) according to claim 1, wherein each eyepiece (36) is formed of a metallic body, the capacitive sensor (50) being the metallic body of the or at least one of the eyepieces (36).
3. Electronic binoculars (10) according to claim 1 or 2, in which the detection block (52) is capable of detecting proximity as a function of phase variations. of an internal signal to the detection block (52) and of the detection threshold, the phase variations being a function of the capacitance of the capacitive sensor (50).
4. Electronic binoculars (10) according to any one of claims 1 to 3, in which the detection block (52) comprises: an oscillator (60) capable of generating a clock signal, called internal signal (CLK), - a phase shifter, called a detection phase shifter (62), capable of phase shifting the internal signal (CLK) according to the capacity of the capacitive sensor (50), to obtain a detection signal (SENSE), - a phase shifter, called a reference phase shifter (64), capable of phase shifting the internal signal (CLK) in an adjustable manner, to obtain a sampling signal (DCLK), the reference phase shifter (64) being adjusted according to the detection threshold, - a sampler (66) capable of sampling the detection signal (SENSE) from the sampling signal (DCLK) to obtain an output signal (Q), the output signal (Q) being capable of taking two states such that: • when the phase of the detection signal (SENSE) is lower than that of the sampling signal (DCLK), the output signal (Q) is in a first state, indicating an absence of detected proximity, and • when the phase of the detection signal (SENSE) is greater than that of the sampling signal (DCLK), the output signal (Q) is in a second state, indicating proximity detection.
5. Electronic binoculars (10) according to claim 4, wherein the sampler (66) is capable of sampling the detection signal (SENSE) on both edges of the sampling signal (DCLK).
6. Electronic binoculars (10) according to claim 4 or 5, in which the detection block (52) further comprises a filter (68) with a double time constant capable of validating the output signal (Q) indicating a detection or not of proximity, only following the obtaining of a predetermined number of consecutive samplings of the detection signal (SENSE) giving an output signal (Q) in the same state.
7. Electronic binoculars (10) according to any one of claims 4 to 6, in which the detection block (52) comprises a protection module (70) between the capacitive sensor (50) and the detection phase shifter (62), the protection module (70) being capable of filtering high frequency radiation and / or of forming protection against electrostatic discharges.
8. Electronic binoculars (10) according to any one of claims 1 to 7, in which the detection threshold is formed by the sum of a sliding average of the surrounding capacity in the absence of detection and a sensitivity deviation.
9. Electronic binoculars (10) according to claim 8, wherein the sensitivity gap is adjustable by a user so as to adjust the distance from which the detection block (52) detects proximity.
10. Electronic binoculars (10) according to any one of claims 1 to 9, wherein the calibration block (54) is capable of updating the detection threshold at a predetermined frequency.
11. Electronic binoculars (10) according to any one of claims 1 to 10, wherein the electronic binoculars (10) are light-intensifying binoculars or thermal binoculars.