阅读说明：本技术 可变光学透射率装置以及相关联的控制方法 (Variable optical transmissivity apparatus and associated control method ) 是由 M·佩卢克斯 于 2019-02-05 设计创作，主要内容包括：一种可变光学透射率装置(2),包括：-能够在初始透射率值(T<Sub>v</Sub>(t<Sub>i</Sub>))与目标透射率值(T<Sub>v target</Sub>)之间改变光学透射率的可变透射率光学器件(4a,4b),以及-被配置用于控制该可变透射率光学器件的透射率参数的控制单元(5),其中,该控制单元(5)被配置用于根据该初始透射率值(T<Sub>v</Sub>(t<Sub>i</Sub>))和该目标透射率值(T<Sub>v target</Sub>)来控制该可变透射率光学器件的响应持续时间。(A variable optical transmissivity apparatus (2) comprising: -capable of being set at an initial transmission value (T) v (t i ) And target transmittance value (T) v target ) A variable transmittance optical device (4a, 4b) for varying an optical transmittance therebetween, and-a control unit (5) configured for controlling a transmittance parameter of the variable transmittance optical device, wherein the control unit (5) is configured for controlling the transmittance parameter in dependence of the initial transmittance value (T;) according to the initial transmittance value (T;) v (t i ) And the target transmittance value (T) v target ) To control the response duration of the variable transmittance optical device.)

1. A variable optical transmissivity apparatus (2) comprising:

-capable of being at an initial transmission value (τ)_v(t_i) And target transmittance value (τ)_v,target) Variable transmittance optical device (4a, 4b) that changes optical transmittance therebetween, and

-a control unit (5) configured for controlling a transmittance parameter of the variable transmittance optical device, wherein the control unit (5) is configured for controlling the transmittance parameter as a function of the initial transmittance value (τ)_v(t_i) And the target transmittance value (τ)_v,target) To control the response of the variable transmittance optical deviceShould be of a duration.

2. The variable optical transmittance device according to claim 1, wherein the response duration is selected according to the preference of a wearer or a group of wearers.

3. Variable optical transmittance device (2) according to any one of claims 1 or 2, wherein said control unit (5) is configured for depending on said initial transmittance value (τ)_v(t_i) With said target transmittance value (τ)_v,target) The sign of the difference controls the response duration, wherein the control unit is configured to control:

omicron for deriving the optical transmittance of the variable transmittance optic from an initial transmittance value (τ)_v(t_i) Decrease to a target transmittance value (τ)_v,target) First response duration (Δ t)_Dn) And an

O for deriving the optical transmission from the initial transmission value (τ)_v(t_i) Increase to the target transmittance value (τ)_v,target) Second response duration (Δ t)_Bl)，

The first response duration (Δ)_Dn) And the second response duration (Δ t)_Bl) Different.

4. A variable optical transmittance device (2) according to any one of claims 1 to 3, wherein the variable optical transmittance device further comprises an ambient light sensor configured for periodically measuring illuminance and detecting a change in illuminance, wherein:

-detecting the change in illuminance when the measured illuminance is different from a reference illuminance during a predetermined hold-off duration,

-the control unit (5) is configured for controlling a transmittance parameter of the variable transmittance optical device when detecting the illumination change after the predetermined hold-off duration, and

-the response duration comprises the predetermined hold-off duration.

5. A variable optical transmittance device (2) according to any one of claims 1 to 4, wherein the variable transmittance optics (4a, 4b) is selected between electrochromic optics and one of liquid crystal optics, and the transmittance parameter of the variable transmittance optics is the optical transmittance of the variable transmittance optics.

6. The variable optical transmittance device (2) according to claim 5, wherein the control unit is configured for controlling the optical transmittance value such that the optical transmittance value varies according to the following equation:

wherein (tau)_v(t_i) Is at time t ═ t)_iThe initial value of the transmission at the time of the exposure,

τ_v(t_i+ t) is at time t_iThe current transmission value at + t,

and isIs dependent on the initial transmittance value τ_v(t_i) And said target transmittance value τ_v,targetA transition function defined such that:

the transition function has a value of 0, 95(τ) of transmittance achieved by the transition function_V，target-τ_V(t_i) A total transition duration defined by the duration of the time interval, and

wherein the response duration comprises the total transition duration.

7. The variable optical transmittance device (2) according to claim 6, wherein the total transition duration is selected to be greater than or equal to 300 milliseconds and less than or equal to 10500 milliseconds.

8. The variable optical transmittance device according to any one of claims 6 or 7,

-when the optical transmittance decreases from a first initial transmittance value to a first target transmittance value, the optical transmittance varies according to a first transition function having a first total transition duration, and

-when the optical transmittance increases from a second initial transmittance value to a second target transmittance value, the optical transmittance varies according to a second transition function having a second total transition duration, and

the second total transition duration is different from the first total transition duration.

9. The variable optical transmittance device according to claim 8, wherein the first initial transmittance value is equal to the second target transmittance value and the first target transmittance value is equal to the second initial transmittance value.

10. The variable optical transmittance device (2) according to any one of claims 1 to 4, wherein said variable transmittance optical device is a photochromic optical device, said variable transmittance device further comprising a transparent heating element, said control unit being configured for controlling said variable transmittance device by setting a predetermined heating duration (Δ t)_heat；Δt_heat,Dn，Δt_heat,Bl) During a predetermined temperature (Temp; temp_Dn，Temp_Bl) To control the duration of the response of the photochromic optical device, the predetermined temperature (Temp; temp_Dn，Temp_Bl) And duration of heating (Δ t)_heat；Δt_heat,Dn，Δt_heat,Bl) Is based on said initial transmittance value (τ)_v(t_i) And the target transmittance value (τ)_v,target) And (4) determining.

11. A variable optical transmissivity apparatus according to any of the preceding claims, wherein the variable transmissivity apparatus further comprises:

-a remote configuration unit configured for sending to the control unit:

-at least a first response duration and a second response duration,

the configuration unit is intended for testing a wearer of the variable transmittance device for different first response durations, second response durations, or for configuring the variable transmittance device to have a first response duration and a second response duration according to the preferences of the wearer.

12. A method for controlling a variable optical transmissivity apparatus, comprising:

-controlling a transmittance parameter of a variable transmittance optic of the variable transmittance device (S200),

wherein the method further comprises:

-according to the initial transmission value (τ)_v(t_i) And target transmittance value (τ)_v,target) To control the duration of the response of the variable transmittance optical device.

13. A method for controlling a variable optical transmittance device according to claim 12, wherein the response duration is selected according to the preference of the wearer.

14. A method for controlling a variable optical transmissivity apparatus according to any one of claims 12 or 13, wherein the method comprises:

-according to said initial transmittance value (τ)_v(t_i) With said target transmittance value (τ)_v,target) Sign of the difference to control the response durationWhich comprises the following steps:

-controlling the optical transmittance for said variable transmittance optical device from an initial transmittance value (τ)_v(t_i) Decrease to a target transmittance value (τ)_v,target) First response duration (Δ t)_Dn) And an

-controlling the optical transmission from an initial transmission value (τ)_v(t_i) Increase to a target transmittance value (τ)_v,target) Second response duration (Δ t)_Bl)，

The first response duration (Δ t)_Dn) And the second response duration (Δ t)_Bl) Different.

15. A computer program comprising one or more stored sequences of instructions that are accessible to a processor and which, when executed by the processor, causes the processor to carry out the steps of the method according to any one of claims 12 to 14.

Technical Field

The present invention relates to variable transmittance optical devices.

Background

In the variable transmittance optical device, the optical transmittance may be automatically changed according to the light emitting environment of the wearer or according to the demand.

The variable transmittance optical device may be used in ophthalmic lenses, sunglasses, ski helmets, or even in building windows, doors or walls. In the case of ophthalmic lenses, sunglasses, ski helmets, or building windows, the optical transmittance may be automatically changed according to the lighting environment or according to the demand. In the case of doors or walls, the optical transmission may be reduced as required to provide some privacy to the people in the room.

The variable transmittance optical device may include, for example, an electrochromic component, a liquid crystal component, or a photochromic component.

It is well known that the duration of response of a variable transmittance lens affects the comfort of the wearer. When the optical transmittance of the lens changes too slowly when using, for example, photochromic lenses, the wearer still feels discomfort due to the change in the luminosity of his environment. Conversely, when the optical transmittance of the lens changes too rapidly, for example when using a liquid crystal lens, the change in the luminosity experienced by the wearer is too abrupt, also resulting in discomfort.

In photochromic lenses, the duration of response depends on the composition and concentration of the photochromic component and may not be adaptable to the wearer's preferences. In electrochromic and liquid crystal lenses, the duration of the response is automatically set by the control unit of the lens and may also not be in accordance with the wearer's preferences.

There is therefore a need to improve the comfort of the wearer of a variable transmittance lens, or more generally the user of a variable transmittance optic, and to improve the adaptation of the response duration to the wearer's preferences.

Disclosure of Invention

In view of the above, it is an object of the present invention to mitigate at least some of the inconveniences of the prior art.

In particular, it is an object of the present invention to improve the comfort of the wearer of a variable transmittance optical device.

It is another object of the invention to improve the adaptation of the duration of the response to the preferences of the wearer. To this end, according to a first aspect, a variable optical transmissivity apparatus is proposed, comprising:

-a variable transmittance optical device capable of varying the optical transmittance between an initial transmittance value and a target transmittance value, an

-a control unit configured for controlling a transmittance parameter of the variable transmittance optical device, wherein the control unit is configured for controlling a response duration of the variable transmittance optical device in dependence of the initial transmittance value and the target transmittance value.

In an embodiment, the variable transmittance device may further comprise one or a combination of the following features:

-selecting the duration of response according to the preferences of a wearer or a group of wearers,

-the control unit is configured for controlling the response duration depending on the sign of the difference between the initial transmittance value and the target transmittance value, wherein the control unit is configured for controlling:

a first response duration for lowering the optical transmittance of the variable transmittance optic from an initial transmittance value to a target transmittance value, and

a second response duration for increasing the optical transmittance from the initial transmittance value to the target transmittance value,

the first response duration is different from the second response duration,

-the variable optical transmittance device further comprises an ambient light sensor configured for periodically measuring illuminance and detecting a change in illuminance, wherein:

detecting the illuminance change when an illuminance measured during a predetermined persistence duration (persistence duration) is different from a reference illuminance,

the control unit is configured to control a transmittance parameter of the variable transmittance optical device when the illuminance change is detected after the predetermined lingering duration, and

the response duration comprises the predetermined linger duration.

-the predetermined lag is defined as a function of the initial transmittance value and the target transmittance value,

-the reference illuminance comprises a first reference illuminance and a second reference illuminance, and the predetermined hold-off duration comprises a first hold-off duration and a second hold-off duration, the illuminance change being detected when the measured illuminance during the first hold-off duration is greater than the first reference illuminance and the measured illuminance during the second hold-off duration is less than the second reference illuminance,

-the first hold-off duration is different from the second hold-off duration,

-the first and second linger durations are dependent on the sign of the difference between the initial and target transmittance values,

-the variable transmittance device further comprises:

-a remote configuration unit configured to send to the control unit:

■ for testing a wearer of the variable transmittance device for different first response durations, second response durations, or for configuring the variable transmittance device to have first and second response durations according to the wearer's preferences.

According to an embodiment, the variable transmittance optical device is selected between one of the liquid crystal optical devices and the electrochromic optical period, and the transmittance parameter of the variable transmittance optical device is an optical transmittance of the variable transmittance optical device.

According to this embodiment, the variable transmittance device may further comprise one or a combination of the following features:

-the control unit is configured for controlling the optical transmittance value such that the optical transmittance value varies according to:

wherein tau is_v(t_i) Is at time t ═ t_iThe initial value of the transmission at the time of the exposure,

τ_v(t_i+ t) is at time t_iA current transmittance value at + t, and

is dependent on the initial transmittance value τ_v(t_i) And said target transmittance value τ_v,targetA transition function defined such that:

is at t ═ t_iIn the case where no change in illuminance is detected thereafter,

in addition, the transition function has a value of 0, 95(τ) reached by the transition function_V，target-τ_V(t_i) A total transition duration defined by a time interval during which the transmittance value lasts, and the response duration comprising the total transition duration,

-the total transition duration is selected to be greater than or equal to 300 milliseconds and less than or equal to 10500 milliseconds,

-the total transition duration is defined in dependence of the initial transmittance value and the target transmittance value,

-said optical transmittance is dependent on having a first total transition duration at when said optical transmittance decreases from a first initial transmittance value to a first target transmittance value_trans,DnIs varied by means of the first transition function of,

when the optical transmittance is increased from the second initial transmittance valueUp to a second target transmittance value, the optical transmittance is determined according to having a second total transition duration Δ t_trans,BlIs varied by a second transition function, and

the second total transition duration is different from the first total transition duration,

-0.2<Δt_trans,Dn/Δt_trans,Bl<0.8，

-the optical transmittance is varied according to a first transition function having a first total transition duration when the optical transmittance is decreased from a first initial transmittance value to a first target transmittance value,

when the optical transmittance increases from a second initial transmittance value to a second target transmittance value, the optical transmittance varies according to a second transition function having a second total transition duration, and when the first initial transmittance value equals the second target transmittance value and the first target transmittance value equals the second initial transmittance value,

the second total transition duration is different from the first total transition duration.

According to another embodiment, the variable transmittance optical device is a photochromic optical device, the variable transmittance apparatus further comprising a transparent heating element, the control unit being configured for controlling a duration of response of the photochromic optical device by setting a predetermined temperature during a predetermined heating duration, the predetermined temperature and heating duration being determined as a function of the initial transmittance value and the target transmittance value.

According to a second aspect, there is also presented a method for controlling the transmittance of a variable transmittance device, the method comprising:

-controlling a transmittance parameter of a variable transmittance optic of the variable transmittance device, wherein the method further comprises:

-controlling a response duration of the variable transmittance optical device as a function of an initial transmittance value and a target transmittance value.

In an embodiment, the method may further comprise one or a combination of the following features:

-selecting the response duration according to the wearer's preference,

-the method comprises:

-controlling the response duration according to the sign of the difference between the initial and target transmittance values, comprising:

■ controls a first response duration for decreasing the optical transmittance of the variable transmittance optical device from an initial transmittance value to a target transmittance value, an

■ controls a second response duration for increasing the optical transmittance from an initial transmittance value to a target transmittance value,

-the first response duration is different from the second response duration,

-the method comprises:

periodically measuring illuminance using an ambient light sensor,

detecting a change in the measured illuminance when the measured illuminance differs from the reference illuminance during the predetermined hold-off duration,

control a transmittance parameter of the variable transmittance optic when the change in illuminance is detected after the predetermined hold-off duration,

-the method comprises:

periodically measuring illuminance using an ambient light sensor,

detect a change in illuminance when the measured illuminance is greater than a predefined range during a first hold-off duration and when the measured illuminance is less than the predefined range during a second hold-off duration, wherein the first hold-off duration is different from the second hold-off duration, and

the control unit controls a transmittance parameter of the variable transmittance optical device when the illuminance variation is detected,

according to a third aspect, there is also presented a computer program, for example a non-transitory computer program, comprising one or more stored sequences of instructions that are accessible to a processor and which, when executed by the processor, causes the processor to carry out the steps of the method described before.

A storage medium, such as a non-transitory storage medium, is also proposed for storing the aforementioned computer program.

Drawings

Further details, aspects and embodiments of the proposed solution will be described, by way of example only, with reference to the accompanying drawings.

Figure 1 shows eyewear including a variable transmittance device according to an embodiment,

figure 2 shows a control unit according to an embodiment,

figure 3 shows a method that may be performed by a control unit for controlling a variable transmittance device in an automatic mode according to an embodiment,

figure 3A illustrates an example of the illuminance measured by a sensor,

figure 3B schematically shows transmittance values of the variable transmittance device as controlled by the control unit according to one embodiment,

figure 3C illustrates transmittance values sent by the command signal of the control unit according to one embodiment,

figure 4 illustrates an example of parameters preferred for a group of users with respect to the first and second response durations,

Detailed Description

Fig. 1 shows a system, here spectacles 1, comprising a variable transmittance device 2 and a frame 3. The variable transmittance device 2 comprises two variable transmittance optics 4a, 4b (here ophthalmic lenses) and at least one control unit 5. In embodiments described herein, the variable transmittance optical device may be an electrochromic lens or a liquid crystal lens. Each variable transmittance optical device 4a, 4b is controlled by a control unit 5 configured for controlling a transmittance parameter of the variable transmittance optical device, here the optical transmittance of an electrochromic or a liquid crystal lens.

The system, i.e. the spectacles 1, may comprise an ambient light sensor 8, placed for example on the frame 3, between the two ophthalmic lenses 4a, 4 b. The ambient light sensor 8 may be configured to detect a change in illuminance in the external environment and/or to transmit the measured illuminance to the control unit 5. Thus, the variable transmittance device 2 is controlled in the "auto mode".

Optionally, the variable transmittance device 2 may comprise a control element 9, which may be used to switch between an automatic mode and a manual mode. In the automatic mode, the user may use the graphical user interface to indicate the control configuration to be used, which includes the target transmittance value to be reached by the variable transmittance optics 4a, 4b, and the parameters that may be used to set a particular response duration to reach that target transmittance value. The control element 9 may be, for example, a tactile slider, a switch with different positions, or a smartphone.

The electrochromic mirror (or more generally the optical device) comprises two transparent layers, for example two plates made of organic or mineral glass, on which at least two electrodes are placed. The inner surfaces of the two transparent layers define cells which are filled with an electrochromic mixture comprising electrochromic compounds. These electrochromic compounds have a characteristic of reversibly changing their color when a voltage is applied due to oxidation and reduction reactions. Thus, by applying an electric field between the at least two electrodes, the optical transmittance of the cell, and thus of the optical device, may be varied. The electrodes should transmit sufficient visible light to allow the wearer to see through the lens without darkening.

Liquid crystal lenses (or more generally optical devices) have a similar structure and comprise two transparent layers on which electrodes are deposited. The cells defined by the inner surfaces of the transparent layers are filled with liquid crystal structures. When an electric field is applied to the electrodes, the liquid crystal changes its orientation and thus modifies the path of light through the liquid crystal cell. The intensity of light passing through the liquid crystal lens or the optical device can be varied by applying different voltages to the electrodes. The electrodes should transmit sufficient visible light to allow the wearer to see through the lens without darkening. Different types of liquid crystal optics may be considered. For example, nematic liquid crystals placed between two crossed polarizers may be considered. Guest-host liquid crystals may also be considered. The guest-host liquid crystal includes a nematic liquid crystal associated with a dichroic dye. When an electric field is applied between the two electrodes, the dichroic dye is aligned in the same direction as the nematic liquid crystal, and the overall transmittance of the liquid crystal optical device depends on the applied electric field. Thus, the guest-host liquid crystal exhibits a transmittance value of greater than 50% due to the absence of crossed polarizers.

Thus, the optical transmittance of an electrochromic or liquid crystal lens or optical device can be controlled by applying different voltage functions to the electrodes of the electrochromic or liquid crystal cell.

In order to control the optical transmittance of the electrochromic or liquid crystal lens or the optical device, the system further comprises a voltage driver 7 configured for receiving command signals from the control unit 5 and outputting voltage signals intended to be applied to the electrodes of the variable transmittance optical device.

The system further includes a source of electrical energy, such as a battery 6, mounted on the temple 3a of the frame 3, as shown in fig. 1. The battery powers the control unit 5 and other electrically powered components such as the sensor 8, the control element 9, and/or the voltage driver 7.

The system may also comprise a visualization unit 10, for example a Light Emitting Diode (LED), which may inform the wearer of the glasses of a malfunction, for example when the batteries are empty or when the ambient light sensor is not functioning properly.

The system may also include a closure detection element 11 located on one temple of the frame 3 (e.g., temple 3 b). The off detection element is configured to detect when the temple 3b is opened or closed and to communicate with the control unit 5 to turn the control unit 5 on or off. The off detection element 11 may be, for example, a magneto-resistive effect element associated with a magnet on the frame between the temple 3b and the variable transmittance optic 4 a.

Fig. 2 shows a control unit 5 according to an embodiment, wherein the variable transmittance device 2 is operated in an automatic mode. The control unit 5 may comprise a processor PROC, a clock TIM, a memory MEM, respective input and output interfaces IN and OUT, and a communication interface COMM. The input interface IN receives the signal sent by the ambient light sensor 8 and sends it to the processor PROC. The processor PROC calculates, from input data received from the signals sent by the ambient light sensor 8, one or more command signals representative of the transmittance values of the variable transmittance optical device, said command signals being intended to be transmitted to the voltage driver 7 via the output interface OUT. The voltage driver 7 generates a corresponding voltage signal which is applied to the electrodes CELL ELECTR of the electrochromic or liquid crystal cells contained within the electrochromic or liquid crystal lenses 4a, 4 b. The processor PROC may also configure the sensors via the output interface OUT. To calculate the command signals, the processor PROC retrieves instructions from the memory MEM. The memory MEM may also contain different variables which are used by the processor PROC when calculating different command signals. The processor PROC may also save or update some variables in the memory MEM if necessary.

The clock TIM is used to time the processor PROC and is a time reference for sending and receiving different signals. The voltage driver 7 and the sensor 8 may be integrated in the control unit 5. The communication interface COMM is configured for establishing a communication between the processor PROC and the remote configuration unit RCU.

The remote configuration unit RCU communicates with the processor PROC of the control unit 5 to configure the control unit 5. The remote configuration unit RCU may for example be a smart phone comprising a dedicated application for configuring the control unit. In particular, the configuration unit may update or load instructions to be executed by the processor PROC and/or may save various variables or parameters on the memory MEM. The remote configuration unit RCU can use Bluetooth via the communication interface^TMThe protocol communicates with the control unit 5.

The remote configuration unit RCU can also be used to test different parameters for the user of the variable transmittance device to adapt the duration of the response of the variable transmittance lens or optic to its preferences. In particular, the remote configuration unit RCU may be used to test different response durations depending on whether the transmittance of the variable transmittance device is decreasing or increasing, or depending on the initial transmittance value and the target transmittance value.

Optionally, the variable transmittance device 2 comprises a control element 9 which the user can use to switch between the automatic mode and the manual mode. The control element 9 may also be used to select a specific control configuration comprising a target transmittance value to be reached and parameters that may be used to set a specific response duration to reach the target transmittance value. According to an embodiment, the control unit is configured for controlling a response duration determined from the target transmittance value and the initial transmittance value. Different response durations may be used depending on the target transmittance value to be achieved and the initial transmittance value of the variable transmittance optical device. The duration of the response may also be selected depending on whether the optical transmittance is decreased or increased to reach the target transmittance value.

The duration of the response of the variable transmittance optical device is controlled by the control unit. The response duration corresponds to a time interval during which the optical transmittance changes from the initial transmittance value to the target transmittance value in response to a change in the lighting environment when the variable transmittance optic is controlled in the automatic mode, or in response to activation of the control element when the variable transmittance optic is controlled in the manual mode. The target transmittance value corresponds to the static transmittance value achieved by the optic at the end of the response duration.

In the case of electrochromic or liquid crystal optics, the target transmittance value may be selected based on the current illumination measured by the ambient light sensor.

The duration of the response can be controlled in a number of different ways, which are shown in the rest of the description.

The variable transmittance device 2 may for example be operated in an automatic mode. In the automatic mode, the ambient light sensor 8 periodically measures the illuminance of the external environment and indicates when a change in illuminance has occurred in the external environment. The ambient light sensor 8 may also provide an indication of the current measured illumination. The processor PROC of the control unit 5 may use the value of the currently measured illuminance to calculate the target transmittance value. The processor PROC then generates one or more command signals that cause the optical transmittance to vary between the initial transmittance value and the target transmittance value, which are sent to the voltage driver 7. The voltage driver 7 generates a corresponding voltage signal which is applied to the command electrodes of the electrochromic or liquid crystal mirrors 4a, 4 b. The voltage signal may be, for example, a Pulse Width Modulation (PWM) signal that may vary a duty cycle to control the optical transmittance of the liquid crystal lens or optic. The optical transmittance may also be varied, for example, by applying a voltage signal having a magnitude corresponding to a predetermined optical transmittance of the electrochromic or liquid crystal lens or optical device, or by applying a voltage signal having a varying frequency.

Fig. 3 illustrates a method for controlling a variable transmittance device including an electrochromic or liquid crystal optic in an automatic mode according to an embodiment. The methods described herein enable control of the response duration of a variable optical transmittance device.

The method includes an initialization step S000, a step S100 of detecting a change in illuminance, and a step S200 of controlling an optical transmittance of the variable optical transmittance device.

The initialization step S000 includes: the memory MEM of the control unit 5 is loaded with instructions and parameters intended to be used by the processor PROC to calculate command signals to control the response duration and the optical transmittance. Further, the initializing step S000 comprises measuring the current illuminance and setting the first transmittance value by sending a command signal representing the transmittance value to be reached.

During step S100, the ambient light sensor 8 periodically measures illuminance and detects whether or not a change in illuminance has occurred. If the ambient light sensor 8 detects an illuminance change, the ambient light sensor indicates to the control unit that the illuminance change has occurred and transmits the current measured illuminance to the processor PROC of the control unit to start step S200.

In step S200, the processor PROC calculates a target transmittance value of the variable optical transmittance device using the current measured illuminance. The processor PROC then generates one or more command signals for controlling the transmittance parameters of the variable optical transmittance device.

The response duration may be varied in a number of ways.

In step S100, a hold-off Δ t may be applied before the sensor 8 indicates a change in illuminance to the processor PROC of the control unit 5_tempo. In this case, when the predetermined hold-off duration Δ t is reached_tempoMeanwhile, when the measured illuminance is different from the reference illuminance, a change in illuminance is detected.

In step S200, the optical transmittance may be varied between the initial transmittance value and the target transmittance value using a transition function having a predetermined duration. The optical transmittance value at a given time t is determined according to:

wherein tau is_v(t_i) Is at time t ═ t_iAn initial transmittance value when, in the automatic mode, corresponding to a transmittance value of the variable transmittance optical device when a change in illumination is detected,

τ_v(t_i+ t) is at time t_iThe current transmission value at + t,

and is

Is dependent on the initial transmission value tau_v(t_i) And target transmittance value τ_v,targetA transition function defined such that:

is at t ═ t_iAnd then no change in illuminance is detected.

In addition, the transition function has a value of 0, 95(τ) of transmittance achieved by the transition function_V，target-τ_V(t_i) ) total transition duration Δ t defined by the duration of the time interval in which they are to be continued_trans。

Thus, in the case of electrochromic or liquid crystal lenses, the response duration comprises the duration of the hold-off and/or the duration of the transition function (referred to as the total transition duration).

According to further illustrated embodiments with reference to fig. 3A, 3B, 3C, the method is described in the context of a variable optical transmittance device as described with reference to fig. 1 and 2.

Fig. 3A, 3B, and 3C illustrate the following embodiments: wherein for different illumination ranges P1, P2, P3, … Pn and two different hold-off durations Δ t_tempo,BlAnd Δ t_tempo,DnTo detect the change in illumination. In this embodiment, the optical transmittance value is varied between the initial transmittance value and the target transmittance value according to a transition function having a total transition duration, which transition function depends on the considered initial transmittance value and target transmittance value. For purposes of illustration, the transition function is represented as a linear transition function. Other forms of transition functions may be considered, as described later.

Fig. 3A shows an example of illuminance measured by the ambient light sensor 8. Fig. 3B schematically represents transmittance values of the variable transmittance device as controlled by the control unit, and fig. 3C illustrates an example of transmittance values sent to the voltage transitioner by a command signal of the control unit.

In this embodiment, the control unit 5 may define a plurality of illuminance ranges, for example four illuminance ranges P1, P2, P3, P4, which are stored in the memory MEM of the control unit 5. Each illumination range comprises a minimum illumination value and a maximum illumination value Imin,1 and Imax,1 respectively; imin,2, Imax, 2; imin,3, Imax, 3. These illumination ranges may be adjacent to each other, i.e. Imax,1 ═ Imin,2, max,2 ═ Imin,3, Imax,3 ═ Imin,4 (as shown in fig. 3A), or may partially overlap, as further described in WO 2017/009544. For clarity, illumination ranges adjacent to each other are further considered herein, but the same reasoning may apply to overlapping ranges. In this embodiment, the transmittance value is determined according to the illuminance range corresponding to the illuminance measured when the illuminance change is detected.

In particular, in the embodiments described herein, the following parameters may be used:

-for a range of illumination P1: [ Imin, 1; imax,1 ═ 0; 1000lx and τ v,1 ═ 0.9.

-for an illuminance range P2, [ Imin, 2; imax,2 ═ 1000 lx; 3000lx ] and τ v,2 ═ 0.55.

-for an illuminance range P3, [ Imin, 3; imax,3 ═ 3000 lx; 10000lx ] and τ v,3 ═ 0.25.

-for an illuminance range P4, [ Imin,4 ═ 10000 lx; imax,4] and τ v,4 ═ 0.1.

-Δt_tempo,Bl1.6s and Δ t_tempo,Dn＝1.2s。

The values defining the illumination range may be adapted to the conditions of use. By associating a single target transmittance value for each illumination range, the electrical consumption of the variable transmittance optic may be reduced. In the alternative, the target transmittance value may be determined from the current measured illumination transmitted by the sensor to the processor.

The method for controlling an electrochromic or liquid crystal optical device is as follows.

During an initialization phase S000, an initial illuminance value is measured and transmitted via the input interface IN to the processor PROC of the control unit 5. The processor PROC determines an illumination range for which the initial illumination value is comprised between a minimum illumination value and a maximum illumination value of one of the predefined illumination ranges. The corresponding minimum and maximum illumination values for the current illumination range are then sent to the memory of the sensor 8. The processor of the control unit 5 also sends the first hold-off duration Δ t via the output interface OUT of the control unit 5_tempo,DnAnd a second hold-off duration Δ t_tempo,BlThe value of (c).

During step S100, the sensor 8 (also including an integrated microprocessor) periodically measures the illuminance to provide a first hold-off duration Δ t_tempo,DnDuring which the currently measured illuminance is greater than the maximum illuminance value of the current illuminance range, or for a second hold-off duration at_tempo,BlDuring which a change in illumination is detected when the currently measured illumination is less than the minimum illumination value of the current illumination range. When the illumination change is detected, the current measured illumination isI.e. the value of the latest measured illuminance, is sent to the processor PROC of the control unit 5 via the input interface IN.

During step S200, the processor determines which illumination range corresponds to the measured illumination and determines a target transmittance value corresponding to the illumination range. Next, the processor generates one or more command signals for varying the optical transmittance between an initial transmittance value before the change in illumination is detected and a target transmittance value, the transmittance value varying according to (1), wherein the transition function is a linear transition function. The processor sends the updated values of the minimum and maximum illuminance of the actual illuminance range to the sensor 8, and the sensor periodically measures the illuminance as described in step S100 until another illuminance change is detected.

Fig. 3A shows an example of illuminance periodically measured by the ambient light sensor 8. The illuminance is first contained within the range P2, and then decreases to be contained within the range P1 and further increases to be within the range P3. Initially, the transmittance value of the variable transmittance lens is set to have a value τ v,2 because the measured luminance value is within the range P2, as can be seen in fig. 3B.

When the measured illumination intensity is greater than t ═ t₀-Δt_tempo,BlAnd t ═ t₀Second hold-off duration at in between_tempo,BlWhen less than Imin,2 in the time interval, the sensor 8 detects the first illumination change. The sensor 8 will then be at, for example, t ═ t₀The measured illuminance value (within the illuminance range P1) is sent to the processor of the control unit 5. The processor generates a signal for rendering the transmittance dependent on having a total transition duration Δ t_trans[τv2,τv1]Is varied between τ v,2 and τ v,1, which are sent to the voltage driver 7. The processor also sends a signal comprising the minimum illuminance value Imin,1 and the maximum illuminance value Imax,1 of the illuminance range P1 to the sensor 8 via the input interface IN.

Then when the measured illumination is greater than t, t 1-delta t_tempo,DnFirst delay duration Δ t between t and t1_tempo,DnIs greater than Imax,1 over a time interval, the sensor 8 detects a secondThe illumination intensity changes. Next, the sensor 8 transmits the current measured illuminance value (within the illuminance range P3) measured when, for example, t is t1 to the processor of the control unit 5. The processor generates a signal for rendering the transmittance dependent on having a total transition duration Δ t_trans[τv(t1),τv3]Is varied between τ v (t1) and τ v,3, which are sent to the voltage driver 7. The processor also sends a signal comprising the minimum illuminance value Imin,3 and the maximum illuminance value Imax,3 of the illuminance range P3 to the sensor 8 via the input interface IN.

In the embodiments described herein, each response duration Δ t_Bl、Δt_DnRespectively including a hold-off duration deltat_tempo,Bl、Δt_tempo,DnAnd the total transition duration at of the transition function used_trans[τv2,τv1]、Δt_trans[τv(t1),τv3]。

In the embodiments described herein, the first hold-off duration Δ t_tempo,DnAnd a second hold-off duration Δ t_tempo,BlDifferent and dependent on the sign of the difference between the initial transmittance value and the target transmittance value. In other words, if the target transmittance value is greater than the initial transmittance value, for example, when τ v,1 is greater than τ v (t0) ═ τ v,2, the hold-off duration Δ t is applied_tempo,BlAnd if the target transmittance value is less than the initial transmittance value, for example when τ v,3 is less than τ v (t1), the lingering duration Δ t is applied_tempo,Dn。

According to another embodiment, the first and second hold-off durations may be determined according to an illuminance outside a current illuminance range for detection measured shortly after the illuminance has changed.

Preferably, the total transition duration Δ t_transHere, is Deltat_trans[τv2,τv1]And Δ t_trans[τv(t1),τv3]Is selected to be greater than or equal to 300 milliseconds and less than or equal to 10500 milliseconds. These values have been tested on wearers of spectacles comprising variable transmittance devices and the wearers have recognised that visual comfort is improved.

In the alternative, the first hold-off duration Δ t_tempo,DnAnd a firstTwo hold-off duration Δ t_tempo,BlMay be equal to each other or equal to zero. When the first drag delay duration is Δ t_tempo,DnAnd a second hold-off duration Δ t_tempo,BlEqual to zero, the response duration corresponding to the transition function

Total transition duration at_trans。

As described previously, the total transition duration Δ t_transIs dependent on the initial transmittance value and the target transmittance value. Total transition duration Δ t_transMay depend on the absolute value of the difference between the initial transmittance value and the target transmittance value and/or the value of the total transition duration may depend on the sign of the difference between the initial transmittance value and the target transmittance value.

According to embodiments, the value of the total transition duration may be different depending on whether the transmittance is increasing or decreasing. The total transition duration Δ t may be applied when the transmittance is reduced, i.e. when the variable transmittance optical device is dimmed_trans,Dn. The total transition duration Δ t may be applied when the transmittance increases, i.e. when the variable transmittance optical device becomes bright_trans,Bl。

According to a variant, the total transition duration Δ t_trans,Dn、Δt_trans,BlIs constant, and Δ t_trans,DnAnd Δ t_trans,BlDifferent. The value of the total transition duration to be selected depends only on the sign of the difference between the initial transmittance value and the target transmittance value.

According to another variant, the total transition duration Δ t_trans,Dn、Δt_trans,BlMay vary. The value of the total transition duration to be selected depends on both the sign and the absolute value of the difference between the initial transmittance value and the target transmittance value. Accordingly, different transition durations Δ t may be used, for example, when optical transmittance increases from τ v,3 to τ v,2 and from τ v,3 to τ v,1_trans,Bl. In addition, the total transition duration Δ t used to reduce the transmission, for example, from τ v,2 to τ v,3_trans,DnAnd increasing the transmission from τ v,3Total transition duration Δ t used up to τ v,2_trans,BlDifferent.

As shown in fig. 3C, the control unit 5 may send a plurality of command signals representing transmittance values to be reached by the electrochromic or liquid crystal optical device. The plurality of command signals may include, for example, a plurality of command signals representing a plurality of values included in the initial transmittance value τ_v(t_i) τ v,2 with target transmittance value τ_v,targetA plurality of command signals of intermediate horizontal transmittance values between τ v,1, and may include a plurality of command signals representing target transmittance values τ v in the case of a linear transition function_{v, target}The command signal of (2). Each intermediate horizontal transmission value may have a different duration controlled by the control unit 5 and may preferably be imperceptible to the wearer, i.e. the intermediate horizontal transmission value varies with a frequency less than the persistence of vision, typically of the order of 30 Hz. As can be seen in fig. 3C, the intermediate transmittance value varies substantially according to equation (1).

Transition function

Can be any transition function defined such that:

according to an embodiment, a transition functionMay be an exponential function defined as:

wherein tau is_v(t_i) Is at time t ═ t_iThe initial value of the transmission at the time of the exposure,

τ_v,targetis the value of the target transmittance and,

t is the current time, an

Is the time constant of the transition function.

The time constant of the exponential transition function may be determined from the initial transmittance value and the target transmittance valueThus, when the transition function is an exponential function, the transition functionTotal transition duration at_transIs equal to the time constant

Three times that of the original.

According to an embodiment, the time constant, and thus the total transition duration, may depend on the initial transmittance value τ_v,(t_i) With target transmittance value tau_v,targetThe sign of the difference such that:

when in useAnd is

When in use

Thus, T_DnAnd t_BlDifferently, such that the exponential transition function has a different time constant depending on whether the transmittance is increasing or decreasingRegardless of the initial transmittance value and the target transmittance value considered.

In addition, T may be_DnAnd T_BlPreferably greater than 100 milliseconds and less than 3500 milliseconds. These values have been tested on wearers of spectacles comprising variable transmittance devices and the wearers have recognised that visual comfort is improved. According to another embodiment, may depend onWhether the optical transmittance value decreases or increases, i.e. depending on the sign of the difference between the initial transmittance value and the target transmittance value, different transition functions are used.

Fig. 4 shows the results of an experiment performed on a wearer of spectacles comprising liquid crystal lenses. By using a remote configuration unit, the control unit 5 is configured with a first and a second exponential transition function, wherein the time constant T is_DnAnd T_BlAre different and are set by a group of users. Fig. 4 shows the value (T) that provides the best visual comfort for each user_DnAnd T_Bl) A graph of (a). As can be seen from the graph, for different Ts_Dn、T_BlThe user can obtain the best visual comfort, each pair (T)_Dn，T_Bl) Different for each user. It also follows that for some wearers or a particular group of wearers, the duration of the response (depending on T) applied when the transmittance of the spectacles increases, i.e. when the variable transmittance optics brightens_Bl) And the duration of the response (dependent on T) applied when the transmission of the spectacles decreases, i.e. when the variable transmission optics darkens_Dn) At different times, visual comfort is improved. As can be seen in FIG. 4, these pairs (T)_Dn，T_Bl) Not on a linear function with a slope of 1.

It will be appreciated that visual comfort for the user may also be improved by varying the total transition duration of the transition functions used, and/or varying the lingering duration.

Thus, different total transition durations, and/or different lingering durations, and/or different transition functions may be tested for a wearer or different groups of wearers using the remote configuration unit. Depending on the results of the test, a specific transition function, and/or a specific lingering duration, and/or a specific total transition duration may be presented to the wearer according to the preferences of the wearer who has performed the test or the preferences of a group of wearers.

In the embodiments described herein, the variable transmittance optics are electrochromic or liquid crystal lenses, and the response duration is controlled in an automatic mode by controlling the optical transmittance of the variable transmittance optics.

In the alternative, the control unit may be controlled in a manual mode. The user can use the control element 9 to set a target transmittance value to be achieved by the variable transmittance optics 4a, 4 b. The parameters that can be used to set a specific response duration to reach the target transmittance value can be preset using a remote control unit, which may optionally include a dedicated user interface.

In another embodiment, the variable transmittance optical device may be a photochromic lens. In this case, the target transmittance value corresponds to the static transmittance value achieved by the optical device once the photochromic reaction is completed after the change in the lighting environment.

The duration of the response can be controlled by controlling the speed at which the photochromic lens is heated such that the optical transmittance changes.

Photochromic lenses or optical devices include photochromic compounds embedded in a polymer layer or within the lens or optical device. The change in optical transmittance of the lens or optic produces a chemical reaction that is initiated by the light absorbed by the photochromic compound. The speed at which the optical transmission changes depends on the composition and concentration of the photochromic compound. The speed of the change in optical transmittance of the photochromic lens or optic can also be controlled by heating the photochromic compound embedded in the polymeric layer or within the lens or optic, for example as disclosed in document WO 2014/071179.

Thus, the duration of the response of the photochromic lens or optic can be controlled by applying a predetermined temperature during a predetermined duration. To this end, the photochromic lens or optic can include a transparent heater that is placed in contact with the polymeric layer containing the photochromic compound or in contact with the photochromic lens or optic. The transparent heater may be a layer of conductive material having a given resistivity and transmitting sufficient UV light to cause the photochromic element to darken or lighten and sufficient visible light for the wearer to see through the lens without darkening. The transparent heater comprises two electrodes connected to a voltage source. Therefore, when a current flows through the conductive material layer forming the transparent heater, the nearby material containing the photochromic compound is heated due to the joule effect. An example of a suitable conductive material is Indium Tin Oxide (ITO). The photochromic compound can also be embedded within a conductive polymer, and/or a conductive polymer with conductive nanoparticles. Thus, two conductive electrodes having a low resistivity are placed on both sides of the conductive polymer comprising the photochromic compound and optionally the conductive nanoparticles. In this case, heat is generated directly into the layer by the joule effect.

In the case of photochromic lenses, the duration of the response of the variable transmittance is controlled by applying a predetermined temperature during a predetermined duration. The response duration may be determined based on the initial transmittance value and the target transmittance value. The initial transmittance value may be measured by a sensor configured to measure a transmittance value of the lens or optic. The target transmittance value may be inferred from the illuminance measurement measured by the ambient light sensor. Depending on the value of the difference between the initial transmittance value and the target transmittance value, the duration of the response, and more particularly the temperature Temp, and the duration of heating Δ t may be determined_heat. The temperature Temp and the duration of heating Δ t are set by command signals sent by the controller, and more particularly by the control unit, to the voltage driver 7_heat. The temperature Temp intended to be applied to the photochromic lens is set by applying a corresponding voltage between the two electrodes of the transparent heater.

According to another embodiment, the value of the response duration, and more particularly the temperature and the heating duration, are determined according to the sign of the difference between the initial transmittance value and the target transmittance value. In this case, the value of the response duration is determined only depending on whether the optical transmittance of the photochromic decreases or increases, i.e., depending on whether the photochromic optic darkens or lightens.

Thus, if the target transmittance value is less than the initial transmittance value,the first temperature Temp may be set by the controller_BlAnd a first heating duration Δ t_heat,BlAnd if the target transmittance value is greater than the initial transmittance value, the second temperature Temp is set by the controller_DnAnd a second heating duration Deltat_heat,Dn. The heating duration can be fine tuned by controlling the current transmittance of the lens or optic using a closed control loop. As previously described, an ambient light sensor may be used to detect changes in the illumination of the lighting environment surrounding the variable transmittance optical device according to one of the previously described methods.

As also described before, according to another embodiment, a hold-off may be applied before the sensor 8 indicates a change in illuminance to the processor PROC of the control unit 5.

According to other embodiments, the variable transmittance device may be incorporated in other types of glasses, such as sunglasses, ski helmets or virtual display glasses, and more generally head-mounted displays. Thus, the variable transmittance optic may be formed from one or two ophthalmic lenses, depending on the type of spectacles, which may not be specifically designed to correct the wearer's ametropia (if correction is not required). The variable transmittance device may also be incorporated into a building window, door or wall. In this case, the variable transmittance optical device is formed of a plexiglas or mineral glass planar substrate mounted on a rectangular frame.