US-12625392-B2 - Dynamic control of transmission value

US12625392B2US 12625392 B2US12625392 B2US 12625392B2US-12625392-B2

Abstract

The disclosure relates to methods, controlling units, eyeglasses, computer programs and computer-readable storage media for controlling an optical transmission of a variable transmission ophthalmic lens. The method includes receiving from a light sensor a measured illuminance of the environment of a wearer, computing a change of illuminance measured during a predetermined time interval, comparing the computed change of illuminance with a first threshold, when the computed change of illuminance is greater than the first threshold, implementing first command configured for varying the transmission of the variable transmission ophthalmic lens from initial transmission value corresponding to a current transmission value to a first target transmission value, according to a first variation profile comprising a first phase during which the transmission overshoots the first target transmission value, and a second phase during which the transmission returns to the first target transmission value.

Inventors

Bruno Fermigier
Cédric GILBERT
Alexandre Gourraud
Marius Peloux
Vincent Roptin

Assignees

ESSILOR INTERNATIONAL

Dates

Publication Date: 20260512
Application Date: 20211014
Priority Date: 20201016

Claims (11)

1 . A method for controlling an optical transmission of a variable transmission ophthalmic lens, the method being implemented by control circuitry and comprising: receiving, from an ambient light sensor, values of a measured parameter related to an illuminance of an environment of a wearer; computing a change of illuminance from the values of the measured parameter during a predetermined time interval; comparing the computed change of illuminance with a first threshold; and when the computed change of illuminance is greater than the first threshold, implementing a first command configured to vary the transmission of the variable transmission ophthalmic lens from an initial transmission value corresponding to a current transmission value to a first target transmission value, the first command being varied according to a first variation profile including a first phase during which the transmission overshoots the first target transmission value, and a second phase during which the transmission returns to the first target transmission value, wherein the method further comprises, when the absolute value of the computed change of illuminance is smaller than, or equal to, the absolute value of the first threshold, implementing a second command configured to vary the transmission of the variable transmission ophthalmic lens according to a monotonic variation profile.
2 . The method according to claim 1 , wherein the first command includes instructions for varying the transmission of the variable transmission ophthalmic lens over time according to a sum of a standard function and of an overshoot function, the standard function defining a monotonous variation of transmission from the initial transmission value to the first target transmission value, and the overshoot function defining the transmission overshoot value, a duration of an overshoot phase and a duration of a decay phase.
3 . The method according to claim 1 , wherein the first command includes instructions for varying the transmission of the variable transmission ophthalmic lens over time according to a sum of a standard function and of an overshoot function, the standard function defining a monotonous variation of transmission from the initial transmission value to the first target transmission value, and the overshoot function defining the transmission overshoot value, a duration of an overshoot phase and a duration of a decay phase, wherein the second command comprises instructions for varying the transmission of the variable transmission ophthalmic lens over time according to the standard function.
4 . The method according to claim 2 , wherein a different overshoot function is used depending on whether the sign of the computed change of illuminance ΔE1 is positive or negative.
5 . The method according to claim 1 , wherein the first target transmission value Tf1 is determined as a function of an illuminance.
6 . The method according to claim 1 , wherein the transmission overshoot value is determined as a function of a difference between the computed change of illuminance and the first threshold.
7 . The method according to claim 1 , further comprising, after implementing the first command, the transmission function of the variable transmission ophthalmic lens having a temporary value, based on the received measurements, computing a further change of illuminance during a further time interval, comparing the computed further change of illuminance with the first threshold, when the absolute value of the computed further change of illuminance is greater than the absolute value of the first threshold, interrupting the transmission variation resulting of the first command and implementing a third command for varying the transmission of the variable transmission ophthalmic lens from a temporary transmission value to a third target transmission value, and when the absolute value of the computed further change of illuminance is smaller than, or equal to, the absolute value of the first threshold, proceeding with the transmission variation resulting of the first command.
8 . The method according to claim 1 , wherein the first threshold is based on a physiological parameter of the wearer.
9 . An apparatus comprising: control circuitry configured to control an optical transmission of a variable transmission ophthalmic lens by being configured to: receive, from an ambient light sensor, values of a measured parameter related to an illuminance of an environment of a wearer, compute a change of illuminance from the values of the measured parameter during a predetermined time interval, compare the computed change of illuminance with a first threshold, when the computed change of illuminance is greater than the first threshold, implement a first command configured to vary the transmission of the variable transmission ophthalmic lens from an initial transmission value corresponding to a current transmission value to a first target transmission value, the first command being varied according to a first variation profile including a first phase during which the transmission overshoots the first target transmission value, and a second phase during which the transmission returns to the first target transmission, and when the absolute value of the computed change of illuminance is smaller than, or equal to, the absolute value of the first threshold, implement a second command configured to vary the transmission of the variable transmission ophthalmic lens according to a monotonic variation profile.
10 . A pair of eyeglasses intended to be worn by a wearer, the pair of eyeglasses comprising: at least one variable transmission ophthalmic lens; an ambient light sensor configured to measure values of a parameter related to an illuminance of an environment; and control circuitry coupled to the variable transmission ophthalmic lens and to the ambient light sensor, the control circuitry being further configured to control circuitry configured to control an optical transmission of a variable transmission ophthalmic lens by being configured to: receive, from an ambient light sensor, values of a measured parameter related to an illuminance of the environment of the wearer, compute a change of illuminance from the values of the measured parameter during a predetermined time interval, compare the computed change of illuminance with a first threshold, when the computed change of illuminance is greater than the first threshold, implement a first command configured to vary the transmission of the variable transmission ophthalmic lens from an initial transmission value corresponding to a current transmission value to a first target transmission value, the first command being varied according to a first variation profile including a first phase during which the transmission overshoots the first target transmission value, and a second phase during which the transmission returns to the first target transmission, and when the absolute value of the computed change of illuminance is smaller than, or equal to, the absolute value of the first threshold, implement a second command configured to vary the transmission of the variable transmission ophthalmic lens according to a monotonic variation profile.
11 . A non-transitory computer-readable storage medium, storing a computer program that when executed by the computer causes the computer to implement the method according to claim 1 .

Description

FIELD OF THE INVENTION The present invention relates to a method for controlling the optical transmission of variable transmission ophthalmic lenses. BACKGROUND OF THE INVENTION As known from the person skilled in the art, variable transmission ophthalmic lenses enable to limit the glare discomfort while preserving vision performance. Variable transmission ophthalmic lenses may comprise, for example, a layer of electrochromics, or a layer of liquid crystals, controlled to modify the optical transmission of the lens upon detection of variations of the light environment of the wearer. Typically, the brighter the environment (E, in lux for instance) becomes, the darker the lenses should be tinted, i.e. the less optical transmission they have, and conversely. Variable transmission lenses are typically controlled to adapt their transmission when a change of illuminance of the environment has been detected and the transmission set is determined as a function of the illuminance measured after the detection of the change of illuminance. Practically, light environment can vary from some lux decades (rather dark inside) to some k.lux decades (bright outside)—not mentioning condition that would correspond to night vision. That means that a ratio around 1000 in some extreme cases, and some ratio of more than 100 ordinarily will characterize the light environment variations experienced by wearers. Considering electrochromic lenses, their transmission may vary between 90% and 10% for class 3 eyewear and between 90% and 4% for class 4 eyewear. The corresponding attenuation factor is thus respectively of 9 (90/10) and 22.5 (90/4). It is thus not possible to sufficiently attenuate the variations of the luminous environment of the wearer to keep a substantially constant level of light perceived by the wearer during those variations. This might result in a discomfort of the wearer while the transmission of the variable transmission lens varies. In view of the above, there is a need to alleviate at least part of the inconveniences of the prior art. In particular, there is a need to provide a method for controlling variable transmission ophthalmic lenses which enhances the comfort of the wearer when the ambient light varies abruptly. PRESENTATION OF THE INVENTION To this end, the present disclosure describes a method for controlling an optical transmission of a variable transmission ophthalmic lens, the method being implemented by a controlling unit and comprising: receiving, from an ambient light sensor, values of a measured parameter related to an illuminance of the environment of the wearer,computing a change of illuminance from the values of the measured parameter during a predetermined time interval,comparing the computed change of illuminance with a first threshold,when the computed change of illuminance is greater than the first threshold, implementing a first command configured for varying the transmission of the variable transmission ophthalmic lens from an initial transmission value corresponding to a current transmission value to a first target transmission value, according to a first variation profile comprising a first phase during which the transmission overshoots the first target transmission value, and a second phase during which the transmission returns to the first target transmission value. By ambient light sensor is understood any sensor that is sensitive to light, such as visible light, IR light or UV light, and that can measure an amount of said light. By “parameter related to an illuminance of the environment of the wearer” is understood a level of light in a wavelength range that the ambient light sensor is sensitive to. The illuminance of the environment of the wearer may be derived, or calculated, from the measured values of said parameter, for example by using a model of light emission spectrum related to a given source of light, for example a model of light emission spectrum of the sun. By first threshold may be understood for example: an absolute threshold, in other words the variation over time of a value of illuminance may be compared to an absolute value, ora relative threshold, in other words the variation over time of a value of illuminance may be divided by a value of an initial illuminance and the obtained ratio may be compared to an absolute value, ora variable threshold being a result of a function of an initial illuminance, in other words, the variable threshold may have a different value whether the ambient light is initially dim or bright. It is considered that the initial transmission value of the ophthalmic lens is the transmission value at an initial instant at which the computed change of illuminance is compared to the first threshold. It is considered that overshooting means exceeding the target, therefore, if the transmission is to increase up to the first target transmission value, then the transmission overshooting the first target transmission value means reaching a higher trans