Vision devices that provide night vision and direct vision of the surrounding scene

Abstract

A visual device (100) for installation on the head of a user (100), comprising: a night vision device (110) for forming a first virtual image; an offset component (120) for projecting the first virtual image into the user's field of view; a shutter (140) such that the offset component is located between the shutter and the user's eye and can have an open position and a closed position, in which the shutter allows light to pass through and in which the shutter blocks the light; a conversion component (160) which can have an open position and a closed position, in which the conversion component allows the emission of the first virtual image or transmits the first virtual image to the offset component in the open position and blocks the image emission or transmission in the closed position; and a control device (150) for controlling the shutter and the conversion component according to an open cycle and a closed cycle, so that the shutter (140) is closed for all or part of the time period during which the conversion component (160) is open, and vice versa.

Description

Technical Field

[0001] The invention relates to a field of view device intended to be mounted on the head of a user and capable of providing the user with both a direct view and a view of a virtual image of a surrounding scene. Background Art

[0002] It is known in the prior art that visual devices of the glasses, head mounted assembly or shield type can be mounted on the head of a user to provide the user with both a view of the surrounding scene seen through an at least partially transparent screen and a view of a virtual image. Such devices form an augmented reality visual device. The virtual image is formed at a distance from the eye and then brought to the user's field of view by a partially transparent offset assembly extending in front of the eye.

[0003] One of the ideas underlying the invention consists in adapting this concept to the field of night vision by proposing a vision device intended to be mounted on the head of a user, capable of providing him both a direct vision of the surrounding scene and a view of the same scene in night vision.

[0004] Another object of the invention is to ensure that such a visual device provides good discrimination when used in low lighting conditions. Summary of the invention

[0005] This object is achieved by a visual device for mounting on a user's head, the visual device comprising:

[0006] - a night vision device configured to form an enhanced and / or infrared image of the surrounding scene, referred to as a first virtual image;

[0007] - an offset component, the offset component being at least partially transparent and configured to be positioned in front of an eye of the user and projecting the first virtual image into the user's field of view when in use;

[0008] - a shutter positioned so that the offset assembly is located between the shutter and the eye of the user in use and capable of having an open position in which the shutter has a first transmittance and a closed position in which the shutter has a second transmittance less than the first transmittance;

[0009] a conversion element capable of having an open position, in which the conversion element allows the emission of the first virtual image by the night vision device or the transmission of the first virtual image from the night vision device to the displacement element, and a closed position, in which the conversion element blocks said emission or said transmission; and

[0010] - A control device configured to control the opening and closing of the shutter and the opening and closing of the conversion component, so that the shutter is closed for all or part of the time period during which the conversion component is opened, and the shutter is opened for all or part of the time period during which the conversion component is closed.

[0011] Throughout the text, it is to be understood that the term "period of time" refers to a duration or a time interval.

[0012] The visual device according to the invention is capable of providing the user with both a direct vision of the surrounding scene seen in a transparent manner at least through the offset assembly and a view of the same scene as a night vision corresponding to a first virtual image formed by the night vision device and projected in the user's field of vision.

[0013] The switching assembly according to the invention can alternatively have an open position or a closed position.

[0014] In its open position, the conversion assembly permits the emission of a first virtual image by the night vision device or the transmission of a first virtual image from the night vision device to the offset assembly. Optical radiation from the night vision device may then form parasitic reflections at the offset assembly and / or on the user's eyes and / or on the user's skin in a facial area located near the eyes.

[0015] In its closed position, the conversion assembly blocks the emission of the first virtual image by the night vision device or the transmission of the first virtual image from the night vision device to the offset assembly. In this case, light radiation from the night vision device cannot form parasitic reflections at the offset assembly and / or on the eyes of the user and / or on the skin of the user in a facial area located near the eyes.

[0016] In the same way, the shutter according to the invention can alternatively have an open position or a closed position.

[0017] In its open position, the shutter allows light from the surrounding scene to pass to the eye, thereby providing the user with direct vision of the surrounding scene.

[0018] In its closed position, the shutter blocks light from passing between the surrounding scene and the user's eyes. Thus, the user is prevented from directly observing the surrounding scene. In this position, the shutter also prevents an observer from seeing light radiation from the night vision device reflected in the offset assembly and / or on the user's eyes and / or on the user's skin in the facial area close to the eyes. This blocking of parasitic reflections by the shutter is even more important in low lighting conditions, where the observer can easily detect parasitic reflections.

[0019] The control device according to the invention makes it possible for the shutter to be in the closed position during at least a portion of the time when the conversion assembly is in the open position. Thus, during at least a portion of the time when the light radiation from the night vision device is able to form parasitic reflections at the offset assembly and / or on the eyes of the user and / or on the skin of the user in the facial area near the eyes, the shutter prevents a third observer from seeing such parasitic reflections.

[0020] Symmetrically, the control device according to the invention also makes it possible for the shutter to be in the open position for at least a portion of the time period during which the conversion assembly is in the closed position. Thus, the shutter allows providing the user with direct vision of the surrounding scene during at least a portion of the time during which the light radiation from the night vision device cannot form parasitic reflections at the displacement assembly and / or on the eyes of the user and / or on the skin of the user in the facial area located near the eyes. In other words, the shutter allows providing the user with direct vision of the surrounding scene during at least a portion of the time during which the risk of light radiation from the night vision device cannot be seen by a third observer.

[0021] Thus, the visual device provides both a direct view of the surrounding scene and a view of the same scene in night vision. These two views of the surrounding scene are not provided to the user simultaneously, which makes it possible to ensure good discrimination when using the visual device even in low lighting conditions.

[0022] According to the invention, the control device has an operating mode in which the control device is configured:

[0023] - controlling a first continuous cycle of opening and closing the shutter; and

[0024] - controlling a second continuous cycle of opening and closing the conversion element;

[0025] In each first cycle and each second cycle, the shutter is closed during the entire or partial time period during which the conversion component is opened, and conversely, the shutter is opened during the entire or partial time period during which the conversion component is closed.

[0026] Advantageously, the control means can control the variation of the duty cycle of a first continuous cycle of opening and closing the shutter and / or the variation of the duty cycle of a second continuous cycle of opening and closing the conversion assembly. The duty cycle of the first cycle is equal to the duration of the shutter being in the open position during the first cycle divided by the total duration of the first cycle. The duty cycle of the second cycle is equal to the duration of the conversion assembly being in the open position during the second cycle divided by the total duration of the second cycle.

[0027] It can be considered that the control performed according to the continuous cycle of opening and closing defines a periodic signal, if so, the periodic signal has a duty cycle that varies with time. The periodic signal preferably has a fixed frequency. As a variable, this periodic signal can have a frequency that varies with time.

[0028] The control device may have an operating mode, in which the control device is configured to control the opening and closing of the shutter and the opening and closing of the conversion component, so that the shutter is closed throughout the period during which the conversion component is open, and the shutter is open throughout the period during which the conversion component is closed.

[0029] Further advantageous features of the invention are mentioned in the claims dependent on claim 1 .

[0030] The invention also encompasses a method implemented in a visual device according to the invention, the method comprising the following steps:

[0031] - opening and closing the shutter, the opening and closing being controlled by the control device; and

[0032] - Opening and closing the conversion component, the opening and closing being controlled by the control device;

[0033] The shutter is closed during the whole or part of the time period during which the conversion component is opened, and the shutter is opened during the whole or part of the time period during which the conversion component is closed.

[0034] The method according to the invention comprises the following steps:

[0035] - opening and closing of the shutter, the opening and closing being controlled by the control device and being performed according to a first continuous cycle of opening and closing of the shutter; and

[0036] - opening and closing the conversion element, the opening and closing being controlled by the control device and being performed according to a second continuous cycle of opening and closing the conversion element;

[0037] In each first cycle and each second cycle, the shutter is closed during the entire or partial time period during which the conversion component is opened, and the shutter is opened during the entire or partial time period during which the conversion component is closed.

[0038] Further advantageous features of the method according to the invention are mentioned in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] When reading the description of the embodiments, which is provided for informational purposes only and is in no way limiting, the invention will be better understood with reference to the accompanying drawings, in which:

[0040] Figure 1ADiagrammatically showing a visual device according to the present invention mounted on a user's head;

[0041] Figure 1B Diagrammatically shows a first embodiment of a visual device according to the invention;

[0042] Figure 1C Graphically demonstrate Figure 1B A visual device in a first configuration;

[0043] Figure 1D Graphically demonstrate Figure 1B A visual device in a second configuration;

[0044] Figure 2 Diagrammatically shows a second embodiment of a visual device according to the invention;

[0045] Figure 3 Diagrammatically showing a third embodiment of a visual device according to the invention;

[0046] Figure 4 Diagrammatically showing a fourth embodiment of a visual device according to the invention;

[0047] Figure 5A diagrammatically showing a method implemented in a visual device according to the invention; and

[0048] Figure 5B A fifth embodiment of a visual device according to the invention is diagrammatically shown. DETAILED DESCRIPTION

[0049] Figure 1A The visual device 100 according to the present invention is diagrammatically shown mounted on the head of a user 10. The visual device 100 forms a wearable device that can be mounted on the head of the user 10 by covering at least a portion of the face at eye level. The visual device 100 is in the form of, for example, glasses, a shield or a head-mounted assembly that integrates the components of the visual device 100. When in use, the visual device 100 is fixed relative to the head of the user 10.

[0050] In the following figures, the user's eyes are shown to facilitate understanding of the present invention. Of course, it should be understood that the eyes are not part of the visual device according to the present invention.

[0051] Figure 1B A visual device 100 according to a first embodiment of the present invention is schematically shown. Here, the visual device 100 comprises: a night vision device 110, a shifting component 120, a shutter 140, a conversion component 160 and a control device 150.

[0052] Night vision device 110 refers to an imaging device for improving night vision in low light conditions. Such a device preferably uses techniques based on light enhancement, thermal detection, low illumination detection (particularly using CMOS sensors), or a combination of such techniques. Such a device is configured to acquire an enhanced and / or infrared image of the surrounding scene. Here, an enhanced image refers to an image formed by amplifying the incident light flux or formed using a high sensitivity sensor.

[0053] The night vision device 110 may include an image intensifier tube provided with a photocathode, a member for electron multiplication, and a fluorescent screen. When in operation, the photocathode converts an incident photon flux into an electron flux. This electron flux is accelerated and propagates to the member for multiplication, and the energy of each accelerated incident electron causes several electron emissions at the member for multiplication. Thus, a strong electron flux is generated. The strong electron flux is received by the fluorescent screen and converted by the fluorescent screen into a strong photon flux. This strong photon flux corresponds to the photon flux incident on the photocathode but stronger. Therefore, the night vision device 110 provides an enhanced image of the surrounding scene, which is projected at the output end of the enhancement tube.

[0054] Alternatively, the night vision device 110 may include a sensor matrix that is ultra-sensitive to visible light and / or sensitive to infrared light in order to acquire an image that is then displayed on a display screen. The sensor matrix may include low-light CMOS or CCD sensors, and / or electron impact CMOS or CCD sensors, and / or enhanced CMOS or CCD sensors, and / or photodiodes sensitive to infrared light, etc. The infrared bands of interest are in particular SWIR (short-wave infrared, corresponding to wavelengths in the range of 1.4 μm to 3 μm), MWIR (mid-wave infrared, corresponding to wavelengths in the range of 3 μm to 8 μm) and / or LWIR (long-wave infrared, corresponding to wavelengths in the range of 8 μm to 15 μm), or even near infrared (corresponding to wavelengths in the range of 0.75 μm to 1.4 μm). Thus, the night vision device 110 provides an enhanced and / or infrared image of the surrounding scene that is displayed on a display screen.

[0055] The image provided at the output of the night vision device 110 is called the "first virtual image". This image is formed by light radiation belonging to the visible spectrum (between 400nm and 700nm). In other words, the night vision device 110 captures wavelengths that may belong to infrared light, but renders the image in the visible spectrum.

[0056] The offset assembly 120 extends between the output end of the night vision device 110 and the area located in front of the user's eye 11 when in use. In use, at least a portion of the offset assembly 120 extends in front of the user's eye 11. The offset assembly 120 is configured to project a first virtual image provided as an output from the night vision device 110 into the user's field of view. The offset assembly is at least partially transparent in the visible spectrum so as to prevent interference with direct vision of the surrounding scene. The offset assembly has a transmittance in visible light greater than or equal to 10%, even greater than or equal to 30%.

[0057] Here, the deflection component 120 comprises a planar waveguide configured to receive as input a first virtual image provided by the night vision device 110, so as to guide these images to an extraction zone located in front of the user's eyes 11 when in use and project these images to the user's eyes 11. Two holographic components are advantageously formed on the planar waveguide, one holographic component for acting to deflect the collimated incident radiation at the night vision device 110, and the other holographic component for scattering light at the extraction zone to the user's eyes.

[0058] According to an alternative not shown, the offset assembly 120 may comprise a prism, in particular a thick glass extending at least partially in front of the eye 11 when in use.

[0059] Figure 1B Light radiation from the surrounding scene and propagating to the night vision device 110 is shown in dashed lines, as well as light radiation provided as an output of the night vision device and propagating to the user's eyes by passing through the offset assembly 120 .

[0060] The shutter 140 is configured to extend in front of the user's eye 11 on the side of the offset assembly 120 opposite to the eye 111 in use. The offset assembly 120 is then located between the shutter 140 and the eye 11. The shutter does not necessarily have the same extension as the offset assembly 120. In particular, the shutter 140 extends towards the portion of the offset assembly that is only located opposite the user's eye in use. According to an alternative that is not shown, the shutter can extend laterally beyond the offset assembly, in particular for blocking as much as possible the light reflected on the user's eye and / or the user's skin in the facial area around the eye.

[0061] Here, the visual device is provided with a glasses-type screen 180, or a shielding curtain or head-mounted goggles that is at least partially transparent in visible light. When in use, the offset component 120 extends between the screen 180 and the user's eyes. Here, the shutter 140 is connected to the screen 180 and extends along all or part of the surface of the screen 180. Here, the shutter 140 extends against the screen 180 on the same side of the screen as the offset component 120. According to an alternative that is not shown, the shutter 140 extends against the screen 180 on the opposite side of the screen from the offset component 120. According to another alternative that is not shown, there is no screen separate from the offset component. The shutter 140 can then be connected against the offset component 120 on the opposite side from the user's eyes. In any case, the shutter 140 can extend along a non-planar surface, for example to follow the curvature of the screen 180.

[0062] The shutter 140 can have two positions in an open position, in which the shutter has a first transmittance, and a closed position, in which the shutter has a second transmittance less than the first transmittance. Preferably, the first transmittance or low ratio is less than 1% in visible light, and the second transmittance or high ratio is greater than 30% in visible light. In any case, the second transmittance must be as high as possible, but a ratio of about 30% will not disturb the user, except to give the user the impression of looking through slightly tinted glasses. For simplicity, it is considered next that in the closed position the shutter blocks light, and in the open position the shutter allows light to pass.

[0063] The shutter 140 may be of a matrix type, for example formed by a liquid crystal screen. Alternatively, the shutter may be of an electrochromic type capable of changing color and transmittance in response to the application of an electric charge through a redox phenomenon. This phenomenon is reversible. The shutter may automatically restore its initial transmittance after a predetermined time interval or in response to the application of a very low electric charge. Thus, the shutter may alternate rapidly between these two positions while still having low energy consumption.

[0064] In its closed position, the shutter 140 blocks the passage of light in both directions. Thus, light from the surrounding scene does not reach the user's eyes, so that the user does not directly see the surrounding scene. In addition, the shutter 140 prevents the observer from seeing light radiation that is transmitted through the offset assembly 120 and / or reflected on the user's eyes and / or reflected on the user's skin in the facial area near the eyes, in particular from the night vision device 110. In this position, the user does not have direct vision of the surrounding scene, but the surrounding scene is also barely visible to the observer.

[0065] In its open position, the shutter 140 allows light to pass in both directions. In this position, light from the surrounding scene reaches the eyes of the user, who can therefore directly observe the scene. In addition, the observer can see light radiation that passes through the offset assembly 120 and / or is reflected on the eyes of the user and / or on the skin of the user in the facial area near the eyes, in particular from the night vision device 110. In this position, the user has direct vision of the surrounding scene, but the surrounding scene is also more visible to the observer.

[0066] Advantageously, the shutter 140 is able to alternate rapidly between these two positions, according to a period of a frequency, for example, greater than or equal to 50 Hz, or even greater than or equal to 140 Hz, wherein the duration of one period corresponds to the duration between two consecutive changes to the open position. In any case, the shutter 140 is advantageously able to alternate between these two positions so that the user does not perceive these alternations due to the persistence of the retina and has a continuous vision of the surrounding scene. The shutter 140 must also be of a quality as compatible as possible with a device that can be worn on the head, have low energy consumption, be compatible with the current conditions of use (temperature, pressure, shocks, etc.), and offer a high extinction rate.

[0067] The conversion assembly 160 is disposed upstream of the offset assembly 120 at the output of the night vision device 110 in the direction in which light circulates at the output of the night vision device 110 .

[0068] The conversion component 160 can have two positions in an open position and a closed position, in which the conversion component allows the first virtual image to be emitted by the night vision device 110 or the first virtual image to be transmitted from the night vision device 110 to the offset component 120, and in which the conversion component blocks the emission or the transmission.

[0069] Here, the conversion assembly 160 is formed by a shutter of the liquid crystal screen or electrochromic type, such as described above. The conversion assembly is configured to allow or block, depending on the circumstances, the transmission of a virtual image from the night vision device 110 to the displacement assembly 120. It can be considered that the conversion assembly 160 blocks or allows the passage of light, even if in practice, blocking may simply correspond to a first transmittance and allowing to correspond to a second transmittance higher than the first transmittance.

[0070] According to an alternative not shown, the switching element 160 is configured to control the emission of operating light or to stop the emission of light of the night vision device 110. An image intensifier tube may, for example, be provided with such a switching element, allowing the tube to alternate between an operating position (emitting light) and a stop position (not emitting light) according to a period of duration that may be less than 1 μs, the duration of one period corresponding to the duration between two consecutive changes to the operating position. In the same way, the display screen of the night vision device may be provided with such a switching element, allowing the screen to alternate between an operating position (emitting light) and a stop position (not emitting light).

[0071] In its open position, the conversion assembly 160 permits the first virtual image to be transmitted from the night vision device 110 to the displacement assembly 120 or simply emitted by the night vision device 110. In this position, the user sees the first virtual image projected in the user's field of vision. However, the light radiation emitted by the night vision device 110 forms parasitic reflections within the displacement assembly 120 and / or on the user's eyes 11 and / or on the user's skin in the facial area located near the eyes.

[0072] In its closed position, the conversion assembly 160 blocks the transmission of the first virtual image from the night vision device 110 to the offset assembly 120 or simply blocks the emission of the first virtual image by the night vision device 110. In this position, the user does not see any image from the night vision device. Since radiation from the night vision device does not reach the offset assembly, there are no parasitic reflections associated with such radiation within the offset assembly 120 and / or on the user's eyes 11 and / or on the user's skin in the facial area near the eyes.

[0073] The control device 150 preferably includes a central unit having a processor that implements a program recorded in a memory. The control device is configured to control the position of the conversion assembly 160 and the position of the shutter 140 so that the shutter 140 is closed for all or part of the time period during which the conversion assembly 160 is open, and the shutter 140 is opened for all or part of the time period during which the conversion assembly 160 is closed.

[0074] When the conversion element 160 is open, the visual device according to the invention provides a view of the surrounding scene in night vision. When the shutter 140 is open, the visual device according to the invention provides a direct view of the surrounding scene in a transparent manner at least through the offset element 120. Thus, the visual device according to the invention can provide both a transparent view of the surrounding scene and a view of the same scene in night vision. However, in order to ensure good discrimination, these two views are not presented simultaneously as in the case of the augmented reality visual devices of the prior art, but are at least partially presented alternately.

[0075] The visual device according to the invention may have in particular Figure 1C and Figure 1D Two configurations are shown in Figure 2.

[0076] exist Figure 1C 1, the conversion assembly 160 permits the transmission of the first virtual image from the night vision device 110 to the offset assembly 120, and the shutter 140 is closed. In this position, the user has a view of the surrounding scene in night vision (due to the first virtual image emitted by the night vision device 110 and projected in the user's field of view), but does not have a direct view of the surrounding scene (due to the closed position of the shutter 140). Due to the closed position of the shutter 140, the observer is prevented from seeing parasitic reflections formed by the optical radiation emitted by the night vision device 110.

[0077] exist Figure 1D In the embodiment of the present invention, the conversion assembly 160 is closed so that the transmission of the first virtual image from the night vision device 110 to the offset assembly 120 is blocked, and the shutter 140 is open. In this position, the user has a direct view of the surrounding scene. In this position, the user does not have a view of the surrounding scene in night vision because the first virtual image is not projected in the user's field of view. In this case, the formation of parasitic reflections visible to the observer is blocked by blocking the light radiation emitted by the night vision device 110 at the conversion assembly 160.

[0078] The control device 150 is configured to open and close the shutter 140 according to a first continuous cycle, each of which includes a time period in which the shutter 140 is open and a time period in which the shutter is closed. By ignoring the transition time, each cycle is formed by each of these two time periods. In each cycle, the shutter 140 will continuously block and allow direct vision of the surrounding scene. Preferably, each cycle lasts less than 50ms, more preferably less than 5ms, for example about 1ms. Due to retinal persistence, the user will continuously have direct vision of the surrounding scene. This vision of the surrounding scene is the so-called natural vision without reducing the user's field of view. The duration of the first cycle defines the frequency of opening and closing of the shutter. For each first cycle, a first duty cycle can be defined as equal to the duration of the shutter 140 in the open position divided by the total duration of this first cycle. Advantageously, this first duty cycle varies with time. Then, the value of the first duty cycle is controlled by the control device 150, for example according to instructions received via a human-machine interface or according to instructions defined using brightness measurement results (or illuminance measurement results). (Throughout this article, the word "brightness" refers to illumination.)

[0079] Similarly, the control device 150 is configured to turn on and off the conversion component 160 according to a second continuous cycle, each of which includes a time period when the conversion component 160 is turned on and a time period when the conversion component 160 is turned off. By ignoring the conversion time, each cycle is formed by each of these two time periods. In each cycle, the conversion component 160 will continuously block and allow the view of the surrounding scene in night vision. Preferably, each cycle lasts less than 50ms, more preferably, less than 5ms, such as about 1ms. Due to retinal persistence, the user will continue to have a view of the surrounding scene in night vision. This view of the surrounding scene in night vision is so-called natural vision without reducing the user's field of view. The duration of the second cycle defines the frequency of opening and closing of the conversion component. For each second cycle, a second duty cycle can be defined as equal to the duration of the conversion component in the open position divided by the total duration of this second cycle. Advantageously, this second duty cycle changes over time. The value of the second duty cycle is then controlled by the control device 150, for example according to instructions received via the man-machine interface or according to instructions defined using brightness measurement results (or illuminance measurement results).

[0080] Furthermore, in each first cycle and each second cycle, the shutter 140 is closed for all or part of the time period during which the conversion component 160 is open, and the shutter 140 is opened for all or part of the time period during which the conversion component 160 is closed. In other words, the control device 150 is configured to control the conversion component 160 and the shutter 140 together according to consecutive cycles, each of which includes the visual device having Figure 1C The configured time periods and visual devices have Figure 1D The configured time period.

[0081] Preferably, the frequencies of the first cycle and the second cycle are high enough to provide the user with a sense of continuous and simultaneous vision of the view of the surrounding scene in night vision and in direct vision. Thus, the user can benefit from natural vision of the surrounding scene in color, even though the ambient lighting usually does not allow this, and have good discrimination when used together.

[0082] Preferably, the first cycle and the second cycle are completely inverted. In other words and by ignoring the switching time, in each first cycle and each second cycle, the shutter 140 is closed over the entire time period during which the conversion component 160 is open, and the shutter 140 is opened over the entire time period during which the conversion component 160 is closed. Therefore, the first virtual image is intermittently projected by the offset component only when the shutter 140 is in the closed position and during the entire duration during which the shutter 140 is in the closed position. This allows the visual device according to the present invention to produce maximum discrimination. This operating mode is particularly advantageous under low light conditions (in other words, under low brightness conditions).

[0083] In the remaining figures and for the sake of clarity, the screens, shields, or head-mounted goggles types of the glasses are not shown.

[0084] Figure 2 A second embodiment of a visual device 200 according to the present invention is shown. Figures 1B to 1D The only difference between the device is that it further includes a brightness measurement component 230 or an illumination measurement component 230.

[0085] The brightness measurement assembly 230 makes it possible to measure the ambient brightness (or ambient illumination) relative to the surrounding scene in the visible spectrum. The brightness measurement assembly is configured to obtain, for example, light intensity measurements or illuminance measurements. The brightness measurement assembly can be formed by a simple photodiode sensitive to visible light or by the night vision device itself (see Figure 3 )form.

[0086] The brightness measurement component 230 is connected to the control device 250 to provide the control device with ambient brightness measurement results (or illuminance measurement results).

[0087] The control device 250 is configured to receive the ambient brightness measurement as input, to determine in response a control instruction dependent on the brightness measurement, and to use the control instruction to control the opening or closing of the shutter 240 and the conversion component 260 .

[0088] Advantageously, the control device 250 is capable of controlling the first cycle of opening and closing the shutter 240 and the second cycle of opening and closing the conversion component 260 such as described above, and making each first cycle have a duty cycle that increases when the value of the brightness measurement result increases, and the duty cycle is equal to the duration that the shutter 240 is in the open position during this cycle divided by the total duration of the cycle.

[0089] When the ambient brightness (or ambient light) is strong, such control of the shutter 240 makes it possible to block as much light from the surrounding scene as possible. Therefore, it is possible to make the average amount of light from the surrounding scene that directly reaches the user equal to the average amount of light from the night vision device that reaches the user. Therefore, it is guaranteed that the view is best rendered as a view in night vision as well as in direct vision. When the ambient brightness is low, this control also makes it possible to block as much parasitic reflections as possible associated with the light from the night vision device 210. Since the visibility of such parasitic reflections depends on the light contrast between such parasitic reflections and the surrounding scene, it is guaranteed that the visual device 200 has good discrimination.

[0090] Preferably, the first cycle and the second cycle are completely in opposite phases. Therefore, the higher the ambient brightness, the more conducive to direct vision of the surrounding scene, and the lower the ambient brightness, the more conducive to night vision of the surrounding scene. These two extreme cases correspond to a duty cycle of 0 or 1 (the shutter 240 is continuously closed and the conversion element 260 is continuously opened, or vice versa, the shutter 240 is continuously opened and the conversion element 260 is continuously closed).

[0091] Figure 3 A third embodiment of a visual device 300 according to the present invention is schematically shown. Figure 2 The embodiment shown differs only in that the night vision device 310 also forms a brightness measurement component 330. In this case, the night vision device 310 may include a module for calculating the average brightness of the entire surrounding scene using the measurement results provided by each of the picture elements of the night vision device 310. Alternatively, only a portion of the detection surface of the night vision device 310 is used to form the brightness measurement component 330.

[0092] Figure 4 A fourth embodiment of a visual device 400 according to the present invention is schematically shown. Figure 2 The embodiment shown differs only in that the control device 450 further comprises a memory 470 storing one or more brightness thresholds (or illumination thresholds). These one or more thresholds together define at least two intervals of brightness values.

[0093] The control device 450 also includes a comparator 451 , which is connected as an input to the memory 470 and the brightness measurement component 430 ; and a processing module 452 , which is connected to the output of the comparator 451 .

[0094] The comparator 451 is configured to compare the brightness measurement result provided by the brightness measurement component 430 with one or more thresholds stored in the memory 470 and thereby derive the interval of brightness values ​​to which the brightness measurement result belongs. This interval is provided to the processing module 452 .

[0095] The processing module 452 is configured to associate each interval with a predetermined operating mode of the visual device and then generate a control command according to the operating mode. The control command is provided to the shutter 440 and the conversion component 460.

[0096] The following three operating modes may be defined below:

[0097] When the ambient brightness is high and greater than a first predetermined threshold, the shutter 240 is continuously in the open position and the conversion component 260 is continuously in the closed position;

[0098] When the ambient brightness is low and is lower than a second predetermined threshold which is lower than the first threshold, the shutter 240 is continuously in the closed position and the conversion component 260 is continuously in the open position;

[0099] When the ambient brightness is between these two thresholds, the shutter 240 and the conversion element 260 are each alternately in the open and closed positions in a completely or partially anti-phase manner according to a continuous cycle such as described above.

[0100] Therefore, when the ambient brightness cannot be judged using night vision, only direct vision of the scene is provided to the user. Conversely, when the ambient brightness is very low, only night vision of the scene is provided to the user. In between, these two visions are combined as described above.

[0101] Reference Figure 5A and Figure 5B , describing a fifth embodiment of a visual device 500 according to the present invention, and a particularly complete example of a method implemented in this visual device.

[0102] The visual device 500 includes a night vision device 5101 and an augmented reality vision device 5102 such as those described above.

[0103] The augmented reality visual device 5102 is, for example, connected to supplementary sensors not shown, and is configured to generate and emit a second virtual image including visual indicators representing the measurements provided by such supplementary sensors. Such indicators may be indicators of position, altitude, speed, direction, etc. Such a device may also include at least one camera connected to an image processing component to identify objects of interest on an image acquired by at least one camera, and in response generate a second virtual image in which such objects of interest are revealed. At least one camera may include a thermal camera, a night vision camera, and / or a camera sensitive to visible light, etc. The device may include two cameras, such as a thermal camera and a camera sensitive to visible light; and a processing module for merging images acquired by each of the two cameras.

[0104] Additionally, the offset assembly 520 can project a second virtual image into the user's field of view.

[0105] Two conversion components 5601 and 5602 are respectively arranged at the output end of the night vision device 5101 and the output end of the augmented reality visual device 5102. Each of these conversion components is as described above. In particular, each of these conversion components 5601 and 5602 can be formed by a hardware component of the liquid crystal screen type or by a signal processing module, which is configured to directly control the emission time of the virtual image by the night vision device 5101 and the augmented reality visual device 5102, respectively.

[0106] The control device 550 is similar to Figure 4 The difference is that it also controls the opening and closing of the conversion component 5602 associated with the augmented reality visual device 5102.

[0107] Here, the memory 570 stores three brightness thresholds Vs1, Vs2, and Vs3, where Vs1 is strictly smaller than Vs2, and Vs2 is strictly smaller than Vs3. These three values ​​together define four intervals of brightness values ​​as follows:

[0108] The interval of ultra-low brightness values, where the brightness is between zero and Vs1 (except Vs1),

[0109] The interval of low brightness values, where the brightness is between Vs1 and Vs2 (except Vs2),

[0110] The interval of high brightness values, where the brightness is between Vs2 and Vs3 (except Vs3), and

[0111] An interval of very high brightness values ​​where the brightness is greater than or equal to Vs3.

[0112] For example:

[0113] Vs1 = 700 μlux, the interval of ultra-low brightness values ​​corresponds to night level 5; and

[0114] Vs2=15mlux, the interval of low brightness values ​​corresponds to night levels 3 and 4.

[0115] In a first step 51 , the brightness measurement component 530 obtains an ambient brightness measurement result and sends this measurement result Lm to the comparator 551 of the control device.

[0116] In step 52 , the comparator 551 compares the measurement result Lm with the minimum threshold value Vs1 .

[0117] If Lm is strictly less than Vs1, the comparator deduces that the value Lm is located in the interval of ultra-low brightness values. In the associated operating mode, the control device 550 controls the shutter 540 and the conversion components 5601, 5602 so that the shutter 540 is constantly maintained in the closed position and the conversion components 5601, 5602 are constantly maintained in the open position (step 53). Therefore, the visual device according to the present invention provides good discrimination. The lack of direct vision of the surrounding scene does not have an adverse effect because this scene is not well illuminated enough to provide satisfactory direct vision to the user. Where applicable, it is possible to adjust the contrast and / or brightness parameters at the output end of each imaging device in the imaging devices 5101, 5102 to provide the user with optimal visual comfort. Alternatively, the conversion component 5602 at the output end of the augmented reality visual device 5102 can be maintained in a closed position.

[0118] If Lm is greater than or equal to Vs1, then at step 54, the comparator compares the brightness value Lm with the threshold value Vs2.

[0119] If Lm is strictly less than Vs2, then at step 55, the comparator deduces therefrom that the value Lm is in the interval of low brightness values. In the associated operating mode, the control means 550 preferably controls the shutter 540 and the conversion component 5601 in a completely inverted form according to a continuous cycle of opening and closing such as described above. Preferably, the control means 550 controls the conversion component 5602 in the same way as the conversion component 5601. As explained above, it is thus ensured that the visual device according to the invention has a good discrimination, while still providing the user with a direct vision of the surrounding scene in addition to the vision of the virtual image.

[0120] If Lm is greater than or equal to Vs2, then at step 56, the comparator compares the brightness value Lm with the threshold value Vs3.

[0121] If Lm is strictly less than Vs3, the comparator deduces therefrom that the value Lm is located in the interval of high brightness values. In the associated operating mode, the control device 550 controls the shutter 540 so that the shutter is constantly maintained in the open position (step 57). Preferably, the control device controls the conversion component 5601 associated with the night vision device so that the conversion component is constantly maintained in the closed position. In fact, under such brightness conditions, night vision is of no interest to the user. Preferably, the control device controls the conversion component 5602 associated with the augmented reality vision device so that the conversion component is constantly maintained in the open position. Therefore, according to the principle of augmented reality vision, direct vision of the surrounding scene is provided, and the direct vision is enriched by information from supplementary sensors. Where applicable, it is possible to adapt the contrast and / or light intensity parameters of the virtual image provided by the augmented reality vision device in order to provide the user with optimal visual comfort.

[0122] If Lm is greater than or equal to Vs3, the comparator deduces from this that the value Lm is located in an interval of very high brightness values. In the associated operating mode, the control means 550 control the opening and closing of the shutter 540 according to a continuous cycle of opening and closing so as to limit the blinding of the user by the ambient light (step 58). Preferably, the control means control the conversion component 5601 associated with the night vision device so that the conversion component is constantly maintained in the closed position. In fact, under such brightness conditions, night vision is of no interest to the user. Preferably, the control means control the conversion component 5602 associated with the augmented reality vision device so that the conversion component is constantly maintained in the open position; or control the conversion component 5602 according to a continuous cycle of opening and closing to allow the conversion component 5602 to be in the open position during at least a part of the time interval when the shutter 540 is in the closed position. Thus, the visibility of the virtual image projected to the user is improved by reducing the amount of light reaching the user's eyes when the virtual image is projected in the user's field of vision.

[0123] Advantageously, when the charge of the battery of the visual device 500 falls below a predetermined threshold, the control means 550 can switch to an operating mode associated with intervals of very low brightness values. Thus, the energy consumption of the visual device 500 is limited to the greatest extent possible.

[0124] Many alternatives to this method may be implemented, depending on whether the visual device includes or does not include augmented reality visual means, with or without associated conversion components.

[0125] According to yet other alternatives, the method does not include all of the operating modes described above.

[0126] The invention is not limited to the examples described above, and many alternatives of the visual apparatus and associated methods may be implemented without departing from the scope of the invention.

[0127] For example, in each of the examples shown, the night vision device and the shutter are located on the same side of the offset component, on the opposite side of the eye when in use. Alternatively, where the offset component is disposed between the night vision device and the shutter, the offset component may be partially reflective.

[0128] According to yet other alternatives, the visual device according to the invention does not comprise a screen of glasses, a shielding curtain or a head mounted device goggles type.

[0129] In each of the embodiments in which the control device is connected to the brightness measurement component, the control device may be provided with a switch for switching from automatic control based on brightness measurement results provided by the brightness measurement component to manual control based on instructions provided by a user via a human-machine interface. According to yet other alternatives, the control device is not connected to the brightness measurement component and includes a human-machine interface for manual control only, in particular control of the duty cycle associated with the opening and closing of the shutter and / or the opening and closing of the conversion component.

[0130] The visual device may comprise one or two components, each of which comprises a night vision device, an offset component, a shutter and a conversion component, and each component is assigned to one of the two eyes of the user. For each of the two components, the individual opening and closing cycles of the shutter and the conversion component may be offset in time. This makes it possible to reduce movement artifacts or other inconveniences that may adversely affect the comfort of the user. Where applicable, the shutters each associated with one of the two eyes may be formed together as a single piece. Similarly, the conversion components each associated with one of the two eyes may be formed together as a single piece. According to yet other alternatives, a single component comprising a night vision device, an offset component, a shutter and a conversion component may be assigned to the two eyes of the user.

[0131] It is possible to adapt the light intensity at the output of the night vision device according to the invention as a function of the duty cycle of the corresponding conversion element in order to compensate for the brightness loss associated with the partial extinction of the output of the night vision device. It is also possible to adapt the light intensity at the output of the night vision device as a function of the ambient brightness in order to improve the visibility of the virtual image projected to the user. In particular, it is possible to adjust the gain of the intensifier tube or the brightness of the display screen.

[0132] Where applicable, the shutter can be spatially divided into several zones in order to locally block light according to the spatial distribution of brightness provided, for example, by a night vision device. Thus, it is possible to filter out from the environment uncomfortable or tiring strong light sources that are present in the field of view and that could interfere with the virtual image.

[0133] When the visual device according to the invention comprises both a night vision device and an augmented reality vision device associated with the same eye of the user, the two devices are advantageously associated with the same offset component. However, each of them may have an individual offset component. An individual offset component may be assigned to each of the two devices. Alternatively, the same conversion component is associated with the two devices. Preferably, the same shutter is assigned to each of the two devices.

Claims

1. A visual device (100; 200; 300; 400; 500), which includes: a night vision device (110; 310; 5101) configured to form an enhanced and / or infrared image of a surrounding scene, referred to as a first virtual image; and an offset assembly (120; 520) which is at least partially transparent and is configured to be positioned in front of an eye of the user and project the first virtual image into the user's field of view when in use; a shutter (140; 240; 440; 540) which allows more or less light to pass between the surrounding scene and the eye of the user, and is positioned so that the offset assembly is located between the shutter and the eye of the user when in use, and is capable of having an open position, in which the shutter has a first transmittance, and a closed position, in which the shutter has a second transmittance less than the first transmittance; a conversion component (160; 260; 460; 5601) capable of having an open position and a closed position, wherein the conversion component in its open position permits emission of the first virtual image by the night vision device or transmission of the first virtual image from the night vision device to the offset component, and wherein the conversion component in its closed position blocks said emission or said transmission; and A control device (150; 250; 450; 550) configured to control the opening and closing of the shutter and the opening and closing of the conversion component; Characteristically, the control device (150; 250; 450; 550) has an operating mode as follows: in the operating mode, the control device is configured to: controlling a first continuous cycle of opening and closing the shutter (140; 240; 440; 540); and Controlling a second continuous cycle of opening and closing the conversion component (160; 260; 460; 5601); Wherein in each first cycle and each second cycle, the shutter (140; 240; 440; 540) is closed for all or part of the time period during which the conversion component (160; 260; 460; 5601) is open, and the shutter is opened for all or part of the time period during which the conversion component is closed.

2. A visual device (100; 200; 300; 400; 500) as described in claim 1, wherein the control device (150; 250; 450; 550) has an operating mode as follows: in the operating mode, the control device is configured to control the opening and closing of the shutter and the opening and closing of the conversion component, so that in each first cycle and each second cycle, the shutter (140; 240; 440; 540) is closed for the entire time period during which the conversion component (160; 260; 460; 5601) is opened, and the shutter is opened for the entire time period during which the conversion component is closed.

3. The visual device (200; 300; 400; 500) as claimed in claim 1 or 2, wherein the visual device further comprises a brightness measurement component (230; 330; 430; 530) for obtaining brightness measurement results in an external environment of the visual device, and wherein, The control device (250; 450; 550) has an operating mode in which the control device is configured to receive a brightness measurement result obtained by the brightness measurement component as input, and to control the opening and closing of the shutter and the opening and closing of the conversion component according to the brightness measurement result.

4. The visual device (200; 300; 400; 500) as claimed in claim 3, wherein the control device (250; 450; 550) has an operating mode as follows: in the operating mode, the control device is configured to: controlling a first continuous cycle of opening and closing the shutter (240; 440; 540); and Controlling a second continuous cycle of opening and closing the conversion element (260; 460; 5601); wherein in each first cycle and each second cycle, the shutter (240; 440; 540) is closed during the entire or partial time period during which the conversion component is open, and conversely the shutter is opened during the entire or partial time period during which the conversion component (260; 460; 5601) is closed; And wherein each first period has a duty cycle that increases as the value of the brightness measurement increases, the duty cycle being equal to the duration that the shutter (240; 440; 540) is in an open position during this period divided by the total duration of the period.

5. The visual device (400; 500) as claimed in claim 3, wherein the control device further comprises: a memory (470; 570) storing a plurality of threshold values; and a comparator (451; 551) configured to compare the brightness measurement to at least one of the threshold values; And wherein the control device (450; 550) is configured to operate according to one of a plurality of predetermined operating modes and according to at least one comparison result provided by the comparator (451; 551), wherein the plurality of operating modes differ due to corresponding rules for controlling the shutter (440; 540) and the conversion component (460; 5601).

6. The visual apparatus (200; 400; 500) of claim 3, wherein the brightness measurement component (230; 430; 530) comprises a light sensor separate from the night vision device (110; 310; 5101).

7. The visual apparatus (300) of claim 3, wherein the brightness measurement component (330) is formed by at least a portion of the night vision device.

8. A visual device (500) as described in claim 1 or 2, wherein it further includes an augmented reality visual device (5102), which is configured to generate an image called a second virtual image, and wherein the offset component (520) is configured to further project the second virtual image into the user's field of view.

9. A method implemented in a visual device (100; 200; 300; 400; 500) as claimed in any one of claims 1 to 8, wherein: The method comprises the following steps: Opening and closing the shutter (140; 240; 440; 540), the opening and closing being controlled by the control device and being performed according to a first continuous cycle of opening and closing the shutter; and Opening and closing the conversion component (160; 260; 460; 5601), the opening and closing being controlled by the control device and being performed according to a second continuous cycle of opening and closing the conversion component; Wherein in each first cycle and each second cycle, the shutter (140; 240; 440; 540) is closed for all or part of the time period during which the conversion component (160; 260; 460; 5601) is open, and conversely the shutter is opened for all or part of the time period during which the conversion component is closed.

10. A method as claimed in claim 9, wherein the steps of opening and closing the shutter (240; 440; 640) and the step of opening and closing the conversion component (160; 260; 460; 5601) are implemented so that: the shutter (140; 240; 440; 540) is in the closed position for the entire time period during which the conversion component (160; 260; 460; 5601) is in the open position, and the shutter is in the open position for the entire time period during which the conversion component is in the closed position.

11. The method of claim 9 or 10, wherein the method is implemented in a visual device (200; 300; 400; 500) further comprising a brightness measurement component, and wherein the method comprises the following steps: The brightness measurement component (230; 330; 430; 530) obtains a brightness measurement result in the external environment of the visual device; The control device (250; 450; 550) receives the brightness measurement result; and The shutter (240; 440; 540) is opened or closed and the conversion component (260; 460; 5601) is opened or closed, and the opening or closing of the shutter and the opening or closing of the conversion component are controlled by the control device according to the brightness measurement result.

12. The method of claim 11, comprising the steps of: Opening and closing the shutter (240; 440; 540), the opening and closing being controlled by the control device and being performed according to a first continuous cycle of opening and closing the shutter; and Opening and closing the conversion component (260; 460; 5601), the opening and closing being controlled by the control device and performed according to a second continuous cycle of opening and closing the conversion component; wherein in each first cycle and each second cycle, the shutter (240; 440; 540) is closed during the entire or partial time period during which the conversion component (260; 460; 5601) is open, and the shutter is opened during the entire or partial time period during which the conversion component is closed; And wherein each first period has a duty cycle that increases as the value of the brightness measurement increases, the duty cycle being equal to the duration that the shutter (240; 440; 540) is in an open position during this period divided by the total duration of the period.

13. The method of claim 11, wherein it comprises the following steps: comparing the brightness measurement result (Lm) obtained by the brightness measurement component (430; 530) with a so-called ultra-low threshold value (Vs1); When the brightness measurement result (Lm) is less than the ultra-low threshold value (Vs1), the shutter (440; 540) is maintained in the closed position and the conversion component (5601) is maintained in the open position through the control of the control device (450; 550).

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