EP1343059B1 - Method and means for illuminating an electronic or an electromechanical device - Google Patents

Method and means for illuminating an electronic or an electromechanical device Download PDF

Info

Publication number
EP1343059B1
EP1343059B1 EP02075879A EP02075879A EP1343059B1 EP 1343059 B1 EP1343059 B1 EP 1343059B1 EP 02075879 A EP02075879 A EP 02075879A EP 02075879 A EP02075879 A EP 02075879A EP 1343059 B1 EP1343059 B1 EP 1343059B1
Authority
EP
European Patent Office
Prior art keywords
light source
lighting
lighting device
light
ambient
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP02075879A
Other languages
German (de)
French (fr)
Other versions
EP1343059A1 (en
Inventor
Romano Cristoni
Gian-Carlo Poli
Joachim Grupp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Asulab AG
Original Assignee
Asulab AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Asulab AG filed Critical Asulab AG
Priority to EP02075879A priority Critical patent/EP1343059B1/en
Publication of EP1343059A1 publication Critical patent/EP1343059A1/en
Application granted granted Critical
Publication of EP1343059B1 publication Critical patent/EP1343059B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G9/00—Visual time or date indication means
    • G04G9/0017—Visual time or date indication means in which the light emitting display elements may be activated at will or are controlled in accordance with the ambient light
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • G—PHYSICS
    • G04—HOROLOGY
    • G04G—ELECTRONIC TIME-PIECES
    • G04G9/00—Visual time or date indication means
    • G04G9/0023—Visual time or date indication means by light valves in general
    • G04G9/0029—Details
    • G04G9/0047—Details electrical, e.g. selection or application of the operating voltage
    • G04G9/0052—Details electrical, e.g. selection or application of the operating voltage using means to adjust the display in accordance with the ambient light, e.g. switching or controlling a supplementary light source
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B44/00—Circuit arrangements for operating electroluminescent light sources

Definitions

  • the present invention relates to a device for providing illumination of a portable electronic device such as a wristwatch to facilitate reading the information provided by this device for a user.
  • the present invention also relates to a method for implementing such a device.
  • Watches whose dial is illuminated with a light source to allow a user to read the time in the dark have been known for many, many years. These watches are distinguished by the intensity of the illumination provided by the light source. For some of them, the light source strongly illuminates the dial of the watch. This may be advantageous in the case where a seller wishes to demonstrate the qualities of his product to a potential buyer and present to the latter the appearance of his watch in case of night use. The user can thus, despite the clarity prevailing in the point of sale, perceive the display of the watch in the illuminated state. On the other hand, if the user of the watch wants to check the time during the night, the high intensity of the lighting may dazzle him.
  • this solution has the significant disadvantage of being a strong energy consumer, which is a serious handicap in the case of portable electronic objects of small dimensions such as a watch whose energy storage capacity is necessarily limited.
  • it has been proposed to illuminate the watches more weakly but still sufficiently, of course, so that the user of such a watch can read hourly or other information in the dark.
  • This second solution has the main merit of being economical from the point of view of electricity consumption.
  • it is practically impossible, unless you retire to a dimly lit place, to demonstrate at the point of sale the qualities of the watch's illumination, because this illumination is too weak to be perceived at all. day.
  • a new step has been taken in the state of the art by proposing, as is done, for example, in the patent US 4,995,016 on behalf of the company Seikosha, to provide the watch with a light sensor capable of detecting the different levels of intensity of the ambient light and to adapt, according to the level of detected brightness, the illumination of the device of display which is provided with the watch.
  • Such a device makes it possible to no longer need to choose, during the construction of the watch, between an intense or weak illumination, for example the display device of the data provided by said watch. So when the ambient illumination is low (in the dark or the penumbra), the illumination of the display device is itself weak, which, from the point of view of the electrical consumption, is very favorable and allows despite everything watch user to consult it at any time, especially in the middle of the night. On the other hand, when the ambient illumination is intense, the light sensor deactivates the lighting means of the watch.
  • a shadow produced, for example, by the sleeve of a shirt distorts the measurement of the degree of ambient brightness.
  • the skilled person has no choice but to increase the detection area. But such a measure greatly affects the aesthetic appearance of the watch and increases the size of it.
  • the object of the present invention is to remedy the drawbacks of the prior art as well as others by providing a lighting device for a portable electronic device which makes it possible to control the illumination of data in a safe and inexpensive manner. displayed by the electronic device according to the intensity of the ambient light.
  • the present invention relates to a lighting device as defined in claim 1.
  • the present invention provides a lighting device whose light source is able both to illuminate the data display device of the apparatus it equips and to detect the degree of intensity of the device. ambient lighting.
  • the present invention therefore makes it possible to no longer have recourse to an independent luminous intensity sensor which is easily understood. very advantageous in that it is thus possible to limit the number of components used, to simplify the construction and thus to limit costs.
  • the reliability of a lighting device according to the invention is improved over that of similar devices known from the prior art.
  • the lighting device according to the invention can advantageously be used in combination with the optical elements used to illuminate the display device such as those described in the application for EP-A-0 860 755 .
  • these optical elements which are used to distribute the light produced by the light source on the surface, for example the dial of a watch, can be used reversibly to collect ambient light under the principle that the paths optics traversed by light are reversible.
  • the use, in combination, of the light source and the elements originally used to diffuse light produced by said light source to collect the ambient light makes it possible to provide the sensor with more reliable information as to the degree of intensity of the light. the ambient brightness than if one used the sensor alone.
  • This sensor comprises, in fact, a limited active surface and the detection signal that it provides can be easily disturbed by a temporary shadow.
  • the light intensity provided by the light source is adapted to the intensity of the measured ambient light.
  • the lighting device if the lighting device is activated while the device that it equips, in particular a timepiece of the wristwatch type, is in full light, said lighting device will provide a strong illumination.
  • a seller of a jewelery will be able to demonstrate the characteristics of the watch to his client and to show him what it will look like when the customer uses his watch for example during the night.
  • the lighting device is activated in a dark place, it will provide less illumination than in daylight. The user will not be dazzled if he consults his watch during the night, and power consumption will be limited, which increases the life of the batteries that power the watch.
  • the time necessary for the human eye to accustom itself to the darkness is taken into account.
  • the lighting device will consider that the user's vision has not yet adapted to the new conditions ambient lighting and will strongly illuminate the display device of the watch.
  • the lighting device will shine weakly.
  • the present invention also relates to a method for illuminating a display device as defined in claim 18.
  • the present invention proceeds from the general inventive idea of using the same light source, not only to illuminate the display device of an electronic or electromechanical device such as a wristwatch, but also as a detector of degree of ambient brightness to match the brightness of the display device illumination to the surrounding conditions.
  • a detector of degree of ambient brightness to match the brightness of the display device illumination to the surrounding conditions.
  • the present invention will be described in connection with an electronic device of the wristwatch type. It goes without saying that the invention is not limited by the type of display device used. It may just as well be a dial above which needles move as a liquid crystal cell. Similarly, the invention is not limited to the horological field and can be applied to any type of portable device such as a measuring device, a wireless phone or laptop or other.
  • the light-emitting diode D3 better known by its English name “Light-Emitting Diode” or "LED”, does not play the role of lighting means but, instead, operates in a mode in which it detects the degree of ambient light.
  • LED Light-Emitting Diode
  • the diode D3, connected to the gate of a transistor T1 thus constitutes with the latter a measuring stage operating in the manner of a current generator whose intensity will depend on the degree of ambient light.
  • This provides a current source controlled by LED D3.
  • the current produced by this current source flows through a resistor R1 which is connected to the drain of the transistor T1 and which makes it possible to create a voltage drop proportional to the current produced by the current generator.
  • a voltage which is a function, on the one hand, of the current produced by the current source controlled by the diode D3, and on the other hand of the value of the resistor R1 itself.
  • the choice of the value of the resistor R1 will allow to set a voltage threshold below which the diode D3, when requested, will produce intense lighting, and beyond beyond which the same diode D3 will produce a limited illumination.
  • interruption means comprising a transistor T2 are connected to the common point between the transistor T1 and the resistor R1.
  • this transistor T2 is always conductive and thus makes it possible to quickly apply the voltage present across said resistor R1 to a capacitor C3.
  • This capacitor C3 is connected in parallel with the resistor R1 via a non-return diode D1 which prevents said capacitor C3 from being discharged through the resistor R1.
  • the capacitor C3 is associated with a resistor R9 with which it constitutes an RC circuit whose constant of time determines the speed at which the capacitor C3 can discharge through the resistor R9.
  • This RC circuit thus constitutes a storage stage which will store a state corresponding to a low or high level of ambient light as a function of the electrical signal produced by the measurement stage. It will be seen later that the value of the time constant of the circuit formed by the capacitor C3 and the resistor R9 is adjusted as a function of the time which is necessary for human vision to adapt to changes in the ambient illumination.
  • the elements described so far thus define two time constants.
  • the first of these constants corresponds to the very short time required to charge the capacitor C3 via the non-return diode D1, the latter having a very low resistance.
  • the second time constant defined by the elements described above corresponds to the time that is necessary for the capacitor C3 to discharge into the resistor R9. This time is longer than the time required to charge the capacitor C3 and is adjusted according to the parameters of human vision as already mentioned. Accordingly, when the device according to the invention is in intense ambient lighting conditions, the current generator that is the LED D3 and the transistor T1 associated with it will charge the capacitor C3 very quickly. If, then, the device according to the invention goes into an environment where the ambient illumination is lower, the capacitor C3 will gradually discharge through the resistor R9.
  • the RC circuit formed by the capacitor C3 and the resistor R9 is connected to the logic input D of a flip-flop 1.
  • This flip-flop 1 constitutes a stage which, when a signal intended to control the ignition of the light source is produced, adapts the intensity of the light supplied by said light source according to the electrical state stored in the storage stage. More precisely, this flip-flop 1 will consider that its input D is at a logic high level "1" or low "0" depending on whether the voltage applied to this input is greater than a first given value, for example 1.7 volts, or less than a second given value, for example 1.2 volts.
  • the flip-flop 1 has the function of applying, without modification, the logic state in which its input D is located at its output Q under the effect of an external bias.
  • this external stress takes the form of a pressure on a push button PB1 which just put t1 (see figure 2 , "start” curve) the output Q of a timing circuit 2 at a high level "1".
  • the output Q of the timer 2 is connected directly to the clock input CLK of the flip-flop 1.
  • the Q output of timer 2 is also connected to the gate of transistor T2.
  • the transistor T2 is conducting throughout the duration of the idle phase of the device according to the invention, and the capacitor C3 is connected to the current generator formed by the light emitting diode D3 and the transistor T1 via the non-return diode D1 and said transistor T2.
  • the storage stage capacitor C3, resistor R9 of the measurement stage must be decoupled immediately. or integration (diode D3, transistor T1, resistor R1) so as not to distort the state of charge of said capacitor C3. This is the role of the signal generated at the output Q of the timer 2 which opens the transistor T2.
  • the transistor T3 controlling the lighting is turned on at time t2 only (see figure 2 curve "LED"), that is to say with a small delay time t1 moment where the push button PB1 is actuated.
  • This delay is introduced by an RC circuit consisting of a capacitor C1 and a resistor R3 arranged between the timer 2 and the transistor T3.
  • This delayed ignition of the diode D3 makes it possible to ensure that the state of the electric charge accumulated in the capacitor C3 is not changed.
  • the logical high or low level of the Q output of flip-flop 1 is represented on the "ligthing" curve of the figure 2 .
  • Two horizontal bold lines indicate the logic state "0" or "1" of the Q output of flip-flop 2.
  • the logic state of output Q is a function of the state of charge of capacitor C3 at time t1 where push button PB1 is pressed. Indeed, as long as the diode D3 functions as a sensor, the voltage across the capacitor C3 fluctuates as a function of the variations in the intensity of the surrounding light (see FIG. figure 2 curve "Vlight").
  • the state of charge of the capacitor C3 freezes and remains substantially the same throughout the duration of the time delay, although the illumination conditions can continue to fluctuate as this is indicated in dashed lines on the "Vlight" curve of the figure 2 . Indeed, because of its time constant, the capacitor C3 slowly discharges in comparison with the duration of the delay signal which corresponds to the duration during which the light emitting diode D3 remains on. At the end of the delay, the capacitor C3 is powered again and quickly regains a charge level corresponding to ambient lighting conditions.
  • the logic high or low level of the Q output of flip-flop 1 is applied to the gate of a transistor T6.
  • the transistor T6 remains open and the diode D3 is supplied with a minimum current through two resistors R4 and R5 connected in series between said diode D3. and said transistor T6.
  • the transistor T6 closes and the diode D3 is then supplied with a maximum current through the single resistor R5. Indeed, when the transistor T6 is conductive, it virtually bypasses the resistance R4 insofar as the value of its internal resistance is very small compared to that of R4.
  • the logic state of the Q output of the timer returns to "0".
  • the transistor T3 opens, causing the extinction of the diode D3.
  • the transistor T2 closes again, so that the capacitor C3 is again connected to the current source stage formed by the diode D3 and the transistor T1 and that its state of charge gradually returns to a level corresponding to the intensity of the ambient light.
  • a second timer 4 resets the logic output Q of the flip-flop 1 (see FIG. figure 2 , "reset" curve).
  • the transistor T3 In the standby state of the device, the transistor T3 is open because the light-emitting diode D3 must not be electrically powered. Conversely, the transistor T2 is closed and thus passing so that the voltage present across the resistor R1 can be applied across the capacitor C3 and thus allows the load of the latter. It is recalled that the voltage across the resistor R1 results from the current flowing through it and which is produced by the light emitting diode D3 and the transistor T1 operating as a current generator controlled by the ambient brightness. It is easy to understand that the state of charge of the capacitor C3 is a function of the potential drop at the common point between the drain of the transistor T1 and the resistor R1.
  • the value of the resistor R1 will determine the value of the voltage applied to the logic input D of the flip-flop 1 and allow it to decide whether its logic input D is at a high level “1” or low “0 ". Depending on whether the logic input D of flip-flop 1 is at "0" or "1” at the moment when the push-button PB1 is actuated, this will determine the intensity of the electric current supplying the diode D3 and therefore the intensity low or high, the illumination produced by said diode D3.
  • the device according to the invention being in the light, suppose that one actuates the push button PB1.
  • the state of charge of the capacitor C3 is at a high level, so that the logic state of the input D of the flip-flop 1 is at its high level "1".
  • the output Q of the timing circuit 2 goes to "1" and controls the transfer of the logic state "1" of the input D of the flip-flop 1 to the Q output of the latter.
  • the timing circuit 2 controls the opening of the transistor T2 so that the state of charge of the capacitor C3 is not distorted by the ignition of the light-emitting diode D3.
  • the timing circuit 2 controls the closing of the transistor T3 so that the diode D3 can be supplied with electric current.
  • the diode D3, however, is energized only briefly after the pusher PB1 has been actuated, this delay being generated by an RC circuit which consists of a capacitor C1 and a resistor R3 and allowing, there also, to ensure that the state of the charge of the capacitor C3 will not be changed by the ignition of the diode D3.
  • the high level "1" of the Q output of the flip-flop 2 is applied to the gate of the transistor T6 to make the latter conductive, so that the current that will feed the diode D3 is limited only by the resistor R5. The lighting of the diode D3 will therefore be maximum.
  • This function is especially useful when a seller of a jewelry store wishes to present to a customer the appearance of the watch when illuminated in dim light. Indeed, despite the clarity that prevails in the point of sale, the diode D3 shine bright enough for the customer to perceive the lighting of said watch.
  • the logic output Q of said timer 2 goes to zero.
  • the transistor T3 opens, causing the extinction of the diode D3, and the transistor T2 closes, so that the capacitor C3 gradually returns to a state of charge corresponding to the ambient brightness.
  • the device according to the invention will be in a situation in which the potential drop created by the resistance R1 which is a function of the degree of intensity of the Ambient brightness will be less than the potential of capacitor C3.
  • the current generator formed by the photoluminescent diode D3 and the transistor T1 can not recharge the capacitor C3 and the latter will begin to gradually discharge through the resistor R9.
  • the rate at which the capacitor C3 discharges is set by the time constant of the circuit constituted by said capacitor C3 and the resistor R9. This is a parameter that can be adjusted according to the values of C3 and R9.
  • the value of the time constant of the circuit C3, R9 will be of the order of a few minutes. It is indeed a duration which corresponds to the average time necessary for the human eye to accustom itself to the darkness when the person comes from a strongly lit environment.
  • the push-button PB1 before the state of charge of the capacitor C3 has reached the value of the potential drop at the common point between the transistor T1 and the resistor R1, the state of the logic input D of flip-flop 1 will be high and diode D3 will shine strongly.
  • the user actuates the pusher PB1 while the capacitor C3 has discharged through the resistor R9 and the voltage at its terminals corresponds to the voltage across the resistor R1, in this case the state the logic input D of the flip-flop 1 will be low and the light-emitting diode D3 will glow weakly.
  • This feature of the invention advantageously allows the user to read the indications provided by his watch in all circumstances. Thus, if the user suddenly switches from lightness to dim light and it operates shortly after the pushbutton PB1, the light-emitting diode D3 will shine strongly to allow him to read the information displayed by his watch because his vision will not be fully accustomed to the darkness.
  • the present invention is not limited to the embodiments that have just been described, and that various modifications and simple variants can be envisaged without departing from the scope of the present invention.
  • the values of the resistors can be programmed by the user in order to adjust the charging and discharging times of the capacitors and thus the adaptation times of the illumination to the day and night vision conditions.
  • Another advantageous embodiment is to use an electronic circuit that pulses a liquid crystal cell to improve the readability and contrast of the display. Indeed, if one measures the contrast of the display of a liquid crystal cell integrated in a watch, there is a beat of this contrast synchronized with the addressing signal of the electrodes of said cell. Thus, if the pulsed illumination is synchronized with the addressing of the liquid crystal cell in an optimized manner, the observer will only perceive the maximum display contrast.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Electric Clocks (AREA)

Description

La présente invention concerne un dispositif destiné à assurer l'éclairage d'un appareil électronique portatif tel qu'une montre-bracelet afin de faciliter la lecture des informations fournies par cet appareil pour un utilisateur. La présente invention concerne également un procédé pour la mise en oeuvre d'un tel dispositif.The present invention relates to a device for providing illumination of a portable electronic device such as a wristwatch to facilitate reading the information provided by this device for a user. The present invention also relates to a method for implementing such a device.

Des montres dont le cadran est illuminé à l'aide d'une source lumineuse pour permettre à un utilisateur de lire l'heure dans l'obscurité sont connues depuis de fort nombreuses années. Ces montres se distinguent entre elles par l'intensité de l'illumination fournie par la source lumineuse. Pour une part d'entre elles, la source lumineuse éclaire fortement le cadran de la montre. Ceci peut s'avérer avantageux dans le cas où un vendeur souhaite démontrer les qualités de son produit à un acheteur potentiel et présenter à ce dernier l'aspect qu'aura sa montre en cas d'utilisation nocturne. L'utilisateur pourra ainsi, malgré la clarté qui règne dans le point de vente, percevoir l'affichage de la montre à l'état éclairé. Par contre, si l'utilisateur de la montre veut consulter l'heure durant la nuit, la forte intensité de l'éclairage risque de l'éblouir. En outre, cette solution présente l'inconvénient notable d'être forte consommatrice d'énergie, ce qui constitue un handicap sérieux dans le cas d'objets électroniques portatifs de faibles dimensions tels qu'une montre dont les capacités de stockage en énergie sont forcément limitées. Pour remédier à cet inconvénient, il a été proposé d'illuminer les montres plus faiblement mais toujours suffisamment, bien entendu, pour que l'utilisateur d'une telle montre puisse lire les informations horaires ou autres dans l'obscurité. Cette seconde solution a comme principal mérite d'être économique du point de vue de la consommation électrique. Par contre, il est pratiquement impossible, à moins de se retirer dans un endroit faiblement éclairé, de faire la démonstration sur le lieu de vente des qualités de l'illumination de la montre, car cette illumination est trop faible pour pouvoir être perçue au grand jour.Watches whose dial is illuminated with a light source to allow a user to read the time in the dark have been known for many, many years. These watches are distinguished by the intensity of the illumination provided by the light source. For some of them, the light source strongly illuminates the dial of the watch. This may be advantageous in the case where a seller wishes to demonstrate the qualities of his product to a potential buyer and present to the latter the appearance of his watch in case of night use. The user can thus, despite the clarity prevailing in the point of sale, perceive the display of the watch in the illuminated state. On the other hand, if the user of the watch wants to check the time during the night, the high intensity of the lighting may dazzle him. In addition, this solution has the significant disadvantage of being a strong energy consumer, which is a serious handicap in the case of portable electronic objects of small dimensions such as a watch whose energy storage capacity is necessarily limited. To remedy this drawback, it has been proposed to illuminate the watches more weakly but still sufficiently, of course, so that the user of such a watch can read hourly or other information in the dark. This second solution has the main merit of being economical from the point of view of electricity consumption. On the other hand, it is practically impossible, unless you retire to a dimly lit place, to demonstrate at the point of sale the qualities of the watch's illumination, because this illumination is too weak to be perceived at all. day.

Un nouveau pas a été franchi dans l'état de la technique en proposant, comme cela est fait, par exemple, dans le brevet US 4,995,016 au nom de la société Seikosha, de munir la montre d'un capteur de lumière capable de détecter les différents niveaux d'intensité de la lumière ambiante et d'adapter, en fonction du niveau de luminosité détecté, l'illumination du dispositif d'affichage dont est munie la montre.A new step has been taken in the state of the art by proposing, as is done, for example, in the patent US 4,995,016 on behalf of the company Seikosha, to provide the watch with a light sensor capable of detecting the different levels of intensity of the ambient light and to adapt, according to the level of detected brightness, the illumination of the device of display which is provided with the watch.

Un tel dispositif permet de ne plus avoir besoin de choisir, lors de la construction de la montre, entre une illumination intense ou faible, par exemple du dispositif d'affichage des données fournies par ladite montre. Ainsi, lorsque l'éclairement ambiant est faible (dans le noir ou la pénombre), l'illumination du dispositif d'affichage est elle-même faible, ce qui, du point de vue de la consommation électrique, est très favorable et permet malgré tout à l'utilisateur de la montre de consulter celle-ci à tout moment, notamment en pleine nuit. Par contre, lorsque l'éclairement ambiant est intense, le capteur de lumière désactive les moyens d'éclairage de la montre. Il est toutefois prévu de munir la montre d'un interrupteur qui, lorsqu'il est activé, permet d'illuminer fortement la montre même en plein jour, par exemple dans une boutique d'horlogerie, afin de permettre au vendeur de démontrer les qualités du produit à un acheteur potentiel et lui présenter l'aspect qu'aura sa montre en cas d'utilisation nocturne. L'ajout d'un composant supplémentaire sous la forme d'un capteur de lumière ne va cependant pas sans poser certains problèmes. Cela représente un coût supplémentaire tant du point de vue du nombre de composants à utiliser que du point de vue du temps de montage et de fabrication, et introduit une source nouvelle de défaillance possible qui peut, à plus au moins long terme, nuire à la fiabilité de l'objet électronique ainsi équipé. De plus, un tel système de détection est directif et ses performances sont fonctions de l'emplacement du capteur. Une ombre produite, par exemple, par la manche d'une chemise fausse la mesure du degré de luminosité ambiante. Pour remédier à ces problèmes, l'homme du métier n'a pas d'autre choix que d'augmenter la surface de détection. Mais une telle mesure nuit considérablement à l'aspect esthétique de la montre et augmente l'encombrement de celle-ci.Such a device makes it possible to no longer need to choose, during the construction of the watch, between an intense or weak illumination, for example the display device of the data provided by said watch. So when the ambient illumination is low (in the dark or the penumbra), the illumination of the display device is itself weak, which, from the point of view of the electrical consumption, is very favorable and allows despite everything watch user to consult it at any time, especially in the middle of the night. On the other hand, when the ambient illumination is intense, the light sensor deactivates the lighting means of the watch. However, it is planned to provide the watch with a switch which, when activated, allows to strongly illuminate the watch even in broad daylight, for example in a watch shop, to allow the seller to demonstrate the qualities of the product to a potential buyer and to present him the appearance that his watch will have in case of night use. The addition of an additional component in the form of a light sensor does not, however, pose certain problems. This represents an additional cost from the point of view of the number of components to be used and from the point of view of the assembly and manufacturing time, and introduces a new source of possible failure which may, in the longer term, affect the reliability of the electronic object thus equipped. In addition, such a detection system is directional and its performance is a function of the location of the sensor. A shadow produced, for example, by the sleeve of a shirt distorts the measurement of the degree of ambient brightness. To remedy these problems, the skilled person has no choice but to increase the detection area. But such a measure greatly affects the aesthetic appearance of the watch and increases the size of it.

Le document WO99/40559 décrit un dispositif d'éclairage pour un appareil électronique ou électromécanique tel qu'une pièce d'horlogerie du type montre-bracelet comprenant un dispositif d'affichage d'une information horaire ou autre, ce dispositif d'éclairage comprenant une source lumineuse pour éclairer le dispositif d'affichage, cette source lumineuse étant également apte à mesurer l'intensité de la lumière ambiante. Dans ce dispositif d'éclairage connu, une unité de contrôle réalise:

  • un étage de mesure agencé pour fournir un signal électrique représentatif des conditions d'éclairement ambiant;
  • un étage de mémorisation agencé pour stocker un état électrique correspondant à un niveau de luminosité faible ou fort en fonction du signal électrique produit par l'étage de mesure, et
  • un étage qui, lorsqu'un signal destiné à commander l'allumage de la source lumineuse est produit, est agencé pour adapter l'intensité de la lumière fournie par ladite source lumineuse en fonction de l'état électrique stocké dans l'étage de mémorisation.
The document WO99 / 40559 discloses a lighting device for an electronic or electromechanical apparatus such as a timepiece of the wristwatch type comprising a device for displaying a time information or the like, this lighting device comprising a light source for illuminating the display device, this light source being also able to measure the intensity of the ambient light. In this known lighting device, a control unit performs:
  • a measurement stage arranged to provide an electrical signal representative of ambient lighting conditions;
  • a storage stage arranged to store an electrical state corresponding to a low or high brightness level depending on the electrical signal produced by the measurement stage, and
  • a stage which, when a signal intended to control the ignition of the light source is produced, is arranged to adapt the intensity of the light supplied by said light source as a function of the electrical state stored in the storage stage .

La présente invention a pour but de remédier aux inconvénients de l'art antérieur ainsi qu'à d'autres encore en procurant un dispositif d'éclairage pour un appareil électronique portatif qui permette de contrôler de façon sûre et peu coûteuse l'illumination des données affichées par l'appareil électronique en fonction de l'intensité de la luminosité ambiante.The object of the present invention is to remedy the drawbacks of the prior art as well as others by providing a lighting device for a portable electronic device which makes it possible to control the illumination of data in a safe and inexpensive manner. displayed by the electronic device according to the intensity of the ambient light.

A cet effet, la présente invention concerne un dispositif d'éclairage tel que défini dans la revendication 1.For this purpose, the present invention relates to a lighting device as defined in claim 1.

Grâce à ces caractéristiques, la présente invention procure un dispositif d'éclairage dont la source lumineuse est capable à la fois d'éclairer le dispositif d'affichage de données de l'appareil qu'elle équipe et de détecter le degré d'intensité de l'éclairage ambiant. La présente invention permet donc de ne plus avoir recours à un capteur d'intensité lumineuse indépendant ce qui est, on le comprendra aisément, fort avantageux dans la mesure où il est ainsi possible de limiter le nombre de composants utilisés, de simplifier la construction et donc de limiter les coûts. En outre, la fiabilité d'un dispositif d'éclairage conforme à l'invention est améliorée par rapport à celle des dispositifs analogues connus de l'art antérieur.Thanks to these features, the present invention provides a lighting device whose light source is able both to illuminate the data display device of the apparatus it equips and to detect the degree of intensity of the device. ambient lighting. The present invention therefore makes it possible to no longer have recourse to an independent luminous intensity sensor which is easily understood. very advantageous in that it is thus possible to limit the number of components used, to simplify the construction and thus to limit costs. In addition, the reliability of a lighting device according to the invention is improved over that of similar devices known from the prior art.

Le dispositif d'éclairage selon l'invention peut être avantageusement utilisé en combinaison avec les éléments optiques servant à éclairer le dispositif d'affichage tels que ceux décrits dans la demande de brevet EP-A-0 860 755 . En effet, ces éléments optiques qui sont utilisés pour répartir la lumière produite par la source lumineuse sur la surface, par exemple du cadran d'une montre, peuvent être utilisés de façon réversible pour collecter la lumière ambiante en vertu du principe selon lequel les chemins optiques parcourus par la lumière sont réversibles. L'utilisation, en combinaison, de la source d'éclairage et des éléments servant originellement à diffuser la lumière produite par ladite source d'éclairage pour collecter la lumière ambiante permet de fournir au capteur une information plus fiable quant au degré d'intensité de la luminosité ambiante que si l'on utilisait le capteur seul. Ce capteur comprend, en effet, une surface active limitée et le signal de détection qu'il fournit peut être facilement perturbé par une ombre passagère.The lighting device according to the invention can advantageously be used in combination with the optical elements used to illuminate the display device such as those described in the application for EP-A-0 860 755 . Indeed, these optical elements which are used to distribute the light produced by the light source on the surface, for example the dial of a watch, can be used reversibly to collect ambient light under the principle that the paths optics traversed by light are reversible. The use, in combination, of the light source and the elements originally used to diffuse light produced by said light source to collect the ambient light makes it possible to provide the sensor with more reliable information as to the degree of intensity of the light. the ambient brightness than if one used the sensor alone. This sensor comprises, in fact, a limited active surface and the detection signal that it provides can be easily disturbed by a temporary shadow.

Selon une autre caractéristique de l'invention, l'intensité lumineuse fournie par la source lumineuse est adaptée à l'intensité de la lumière ambiante mesurée. Ainsi, si le dispositif d'éclairage est activé alors que l'appareil qu'il équipe, en particulier une pièce d'horlogerie du type montre-bracelet, se trouve en pleine lumière, ledit dispositif d'éclairage fournira une illumination forte. De la sorte, un vendeur d'une joaillerie pourra faire la démonstration des caractéristiques de la montre à son client et lui présenter l'aspect qu'aura cette dernière lorsque le client utilisera sa montre par exemple durant la nuit. Au contraire, si le dispositif d'éclairage est activé dans un lieu sombre, il fournira une illumination moins forte qu'en plein jour. L'utilisateur ne sera ainsi pas ébloui s'il consulte sa montre durant la nuit, et la consommation électrique sera limitée, ce qui permet d'augmenter la durée de vie des batteries qui alimentent la montre.According to another characteristic of the invention, the light intensity provided by the light source is adapted to the intensity of the measured ambient light. Thus, if the lighting device is activated while the device that it equips, in particular a timepiece of the wristwatch type, is in full light, said lighting device will provide a strong illumination. In this way, a seller of a jewelery will be able to demonstrate the characteristics of the watch to his client and to show him what it will look like when the customer uses his watch for example during the night. On the contrary, if the lighting device is activated in a dark place, it will provide less illumination than in daylight. The user will not be dazzled if he consults his watch during the night, and power consumption will be limited, which increases the life of the batteries that power the watch.

Selon encore une autre caractéristique de l'invention, on prend en compte le temps nécessaire à l'oeil humain pour s'accoutumer à l'obscurité. Ainsi, si un utilisateur passe rapidement d'un lieu éclairé à un lieu sombre et qu'il veut consulter sa montre immédiatement après, le dispositif d'éclairage considérera que la vision de l'utilisateur ne s'est pas encore adaptée aux nouvelles conditions d'éclairement ambiant et éclairera fortement le dispositif d'affichage de la montre. Par contre, si l'utilisateur veut consulter sa montre après une période plus longue où il sera considéré que la vue dudit utilisateur s'est adaptée aux conditions de vision nocturnes, le dispositif d'éclairage brillera faiblement.According to yet another characteristic of the invention, the time necessary for the human eye to accustom itself to the darkness is taken into account. Thus, if a user passes quickly from a lighted place to a dark place and wants to consult his watch immediately after, the lighting device will consider that the user's vision has not yet adapted to the new conditions ambient lighting and will strongly illuminate the display device of the watch. On the other hand, if the user wants to consult his watch after a longer period where he will be considered that the view of said user has adapted to the night vision conditions, the lighting device will shine weakly.

La présente invention concerne également un procédé pour éclairer un dispositif d'affichage comme défini dans la revendication 18.The present invention also relates to a method for illuminating a display device as defined in claim 18.

D'autres caractéristiques et avantages de la présente invention ressortiront plus clairement de la description détaillée qui suit d'un exemple de réalisation du dispositif d'éclairage selon l'invention, cet exemple étant donné à titre purement illustratif et non limitatif seulement, en liaison avec les dessins annexés sur lesquels :

  • la figure 1 est une représentation du schéma électrique du dispositif d'éclairage selon l'invention, et
  • la figure 2 est un histogramme montrant l'évolution de la tension aux bornes de différents éléments du dispositif d'éclairage selon l'invention.
Other features and advantages of the present invention will emerge more clearly from the following detailed description of an exemplary embodiment of the lighting device according to the invention, this example being given for purely illustrative and non-limiting purposes only, in connection with with the accompanying drawings in which:
  • the figure 1 is a representation of the electrical diagram of the lighting device according to the invention, and
  • the figure 2 is a histogram showing the evolution of the voltage across different elements of the lighting device according to the invention.

La présente invention procède de l'idée générale inventive qui consiste à utiliser une même source d'éclairage, non seulement pour éclairer le dispositif d'affichage d'un appareil électronique ou électromécanique tel qu'une montre-bracelet, mais également comme détecteur du degré de luminosité ambiant pour adapter l'intensité de l'éclairage du dispositif d'affichage aux conditions environnantes. Grâce à cette caractéristique, on limite le nombre de composants à utiliser et on rend ainsi la fabrication d'un tel dispositif d'affichage plus simple et donc plus économique. En outre, un tel dispositif d'affichage présente une meilleure fiabilité.The present invention proceeds from the general inventive idea of using the same light source, not only to illuminate the display device of an electronic or electromechanical device such as a wristwatch, but also as a detector of degree of ambient brightness to match the brightness of the display device illumination to the surrounding conditions. With this feature, it limits the number of components to use and thus makes the manufacture of such a display device simpler and therefore more economical. In addition, such a display device has a better reliability.

La présente invention va être décrite en liaison avec un appareil électronique du type montre-bracelet. Il va de soi que l'invention n'est pas limitée par le type de dispositif d'affichage utilisé. Il peut tout aussi bien s'agir d'un cadran au-dessus duquel se déplacent des aiguilles que d'une cellule à cristal liquide. De même, l'invention n'est pas limitée au domaine horloger et peut être appliquée à tout type d'appareil portatif tel qu'un appareil de mesure, un téléphone sans fil ou portable ou autres.The present invention will be described in connection with an electronic device of the wristwatch type. It goes without saying that the invention is not limited by the type of display device used. It may just as well be a dial above which needles move as a liquid crystal cell. Similarly, the invention is not limited to the horological field and can be applied to any type of portable device such as a measuring device, a wireless phone or laptop or other.

L'illumination d'une montre-bracelet peut se faire à l'aide de différents moyens parmi lesquels on peut citer :

  • les feuilles électroluminescentes sur lesquelles sont imprimés des motifs ou qui sont utilisées en combinaison avec un cadran partiellement transparent;
  • un guide de lumière, par exemple en forme d'anneau, comme décrit dans la demande de brevet EP-A-0 860 755 ;
  • un guide de lumière planaire qui est soit disposé sur le cadran (éclairage réverbère), soit au-dessus de celui-ci lorsque ce cadran est partiellement transparent (rétro-éclairage);
  • les aiguilles de la montre comme cela est décrit, par exemple dans le brevet US 4,995,022 ;
  • l'illumination lampadaire comme décrit dans le brevet US 6,106,127 .
The illumination of a wristwatch can be done using various means among which may be mentioned:
  • electroluminescent sheets on which patterns are printed or which are used in combination with a partially transparent dial;
  • a light guide, for example in the form of a ring, as described in the application for EP-A-0 860 755 ;
  • a planar light guide which is either disposed on the dial (reverberation lighting) or above it when this dial is partially transparent (backlighting);
  • the hands of the watch as described, for example in the US Patent 4,995,022 ;
  • streetlight illumination as described in the US Patent 6,106,127 .

Les méthodes décrites succinctement ci-dessus sont plus particulièrement adaptées pour la mise en oeuvre de l'invention. Bien sûr, ces méthodes restent valables dans le cas où le cadran de la montre est partiellement ou entièrement constitué par une cellule d'affichage à cristaux liquides.The methods described briefly above are more particularly suitable for the implementation of the invention. Of course, these methods remain valid in the case where the dial of the watch is partially or entirely constituted by a liquid crystal display cell.

On se réfère tout d'abord à la figure 1. Pendant la phase veille, la diode électroluminescente D3, mieux connue sous sa dénomination anglo-saxonne "Light-Emitting Diode" ou "LED", ne joue pas le rôle de moyen d'éclairage mais, au contraire, fonctionne dans un mode dans lequel elle détecte le degré de luminosité ambiant. Dans le cadre de la présente invention, on pourra utiliser, par exemple, les diodes commercialisées par la société Agilent sous les références HSMB-190C et HSMC-S690 ou la diode commercialisée par Stanley sous la référence FR1111C. La diode D3, reliée à la grille d'un transistor T1, constitue ainsi avec ce dernier un étage de mesure fonctionnant à la façon d'un générateur de courant dont l'intensité va dépendre du degré de luminosité ambiant. On dispose ainsi d'une source de courant commandée par la LED D3. Le courant produit par cette source de courant traverse une résistance R1 qui est reliée au drain du transistor T1 et qui permet de créer une chute de tension proportionnelle au courant produit par ledit générateur de courant. On dispose ainsi d'une tension qui est fonction, d'une part du courant produit par la source de courant commandée par la diode D3, et d'autre part de la valeur de la résistance R1 proprement dite. Comme on le comprendra mieux dans la suite de la description, le choix de la valeur de la résistance R1 va permettre de fixer un seuil de tension en deçà duquel la diode D3, lorsqu'elle sera sollicitée, produira un éclairage intense, et au-delà duquel la même diode D3 produira un éclairage limité.We first refer to the figure 1 . During the standby phase, the light-emitting diode D3, better known by its English name "Light-Emitting Diode" or "LED", does not play the role of lighting means but, instead, operates in a mode in which it detects the degree of ambient light. In the context of the present invention, it is possible to use, for example, the diodes sold by Agilent under the references HSMB-190C and HSMC-S690 or the diode marketed by Stanley under the reference FR1111C. The diode D3, connected to the gate of a transistor T1, thus constitutes with the latter a measuring stage operating in the manner of a current generator whose intensity will depend on the degree of ambient light. This provides a current source controlled by LED D3. The current produced by this current source flows through a resistor R1 which is connected to the drain of the transistor T1 and which makes it possible to create a voltage drop proportional to the current produced by the current generator. There is thus a voltage which is a function, on the one hand, of the current produced by the current source controlled by the diode D3, and on the other hand of the value of the resistor R1 itself. As will be better understood in the following description, the choice of the value of the resistor R1 will allow to set a voltage threshold below which the diode D3, when requested, will produce intense lighting, and beyond beyond which the same diode D3 will produce a limited illumination.

Comme on peut le voir sur le schéma électrique, des moyens d'interruption comprenant un transistor T2 sont reliés au point commun entre le transistor T1 et la résistance R1. Pendant la phase de veille, ce transistor T2 est toujours conducteur et permet ainsi d'appliquer de manière rapide la tension présente aux bornes de ladite résistance R1 à un condensateur C3. Ce condensateur C3 est monté en parallèle sur la résistance R1 via une diode anti-retour D1 qui empêche ledit condensateur C3 de se décharger au travers de la résistance R1. De même, le condensateur C3 est associé à une résistance R9 avec laquelle il constitue un circuit RC dont la constante de temps détermine la vitesse à laquelle le condensateur C3 peut se décharger au travers de la résistance R9. Ce circuit RC constitue ainsi un étage de mémorisation qui va stocker un état correspondant à un niveau de luminosité ambiante faible ou fort en fonction du signal électrique produit par l'étage de mesure. On verra ultérieurement que la valeur de la constante de temps du circuit formé par le condensateur C3 et la résistance R9 est ajustée en fonction du temps qui est nécessaire à la vision humaine pour s'adapter aux modifications de l'éclairement ambiant.As can be seen in the electrical diagram, interruption means comprising a transistor T2 are connected to the common point between the transistor T1 and the resistor R1. During the standby phase, this transistor T2 is always conductive and thus makes it possible to quickly apply the voltage present across said resistor R1 to a capacitor C3. This capacitor C3 is connected in parallel with the resistor R1 via a non-return diode D1 which prevents said capacitor C3 from being discharged through the resistor R1. Similarly, the capacitor C3 is associated with a resistor R9 with which it constitutes an RC circuit whose constant of time determines the speed at which the capacitor C3 can discharge through the resistor R9. This RC circuit thus constitutes a storage stage which will store a state corresponding to a low or high level of ambient light as a function of the electrical signal produced by the measurement stage. It will be seen later that the value of the time constant of the circuit formed by the capacitor C3 and the resistor R9 is adjusted as a function of the time which is necessary for human vision to adapt to changes in the ambient illumination.

Les éléments décrits jusqu'ici définissent donc deux constantes de temps. La première de ces constantes correspond au temps, très bref, qui est nécessaire pour charger le condensateur C3 via la diode anti-retour D1, cette dernière présentant une résistance très faible. La seconde constante de temps définie par les éléments décrits ci-avant correspond au temps qui est nécessaire au condensateur C3 pour se décharger dans la résistance R9. Ce temps est plus long que le temps nécessaire pour charger le condensateur C3 et est ajusté en fonction des paramètres de la vision humaine comme déjà mentionné. En conséquence, lorsque le dispositif selon l'invention se trouve dans des conditions d'éclairement ambiant intenses, le générateur de courant que constituent la LED D3 et le transistor T1 qui lui est associé va charger très rapidement le condensateur C3. Si, ensuite, le dispositif selon l'invention passe dans un environnement où l'éclairement ambiant est plus faible, le condensateur C3 va se décharger progressivement au travers de la résistance R9. Il faut bien comprendre, en effet, que si le dispositif selon l'invention passe d'un endroit qui est fortement éclairé à un endroit qui l'est moins, on se trouve, à l'instant de cette transition, dans une situation où la chute de potentiel créée par la résistance R1 qui est, rappelons-le, proportionnelle au courant produit par la diode D3, est inférieure au potentiel du condensateur C3. En conséquence, le générateur de courant formé par ladite diode D3 et le transistor T1 ne peut pas recharger le condensateur C3. Cela ne sera à nouveau possible qu'au moment où le condensateur C3 se sera suffisamment déchargé et que son potentiel deviendra inférieur au potentiel présent aux bornes de la résistance R1. Ainsi, les fluctuations de la tension aux bornes du condensateur C3 sont le reflet fidèle des variations de l'intensité de l'éclairage ambiant.The elements described so far thus define two time constants. The first of these constants corresponds to the very short time required to charge the capacitor C3 via the non-return diode D1, the latter having a very low resistance. The second time constant defined by the elements described above corresponds to the time that is necessary for the capacitor C3 to discharge into the resistor R9. This time is longer than the time required to charge the capacitor C3 and is adjusted according to the parameters of human vision as already mentioned. Accordingly, when the device according to the invention is in intense ambient lighting conditions, the current generator that is the LED D3 and the transistor T1 associated with it will charge the capacitor C3 very quickly. If, then, the device according to the invention goes into an environment where the ambient illumination is lower, the capacitor C3 will gradually discharge through the resistor R9. It must be understood, indeed, that if the device according to the invention passes from a place which is strongly lit to a place which is less bright, we are, at the moment of this transition, in a situation where the potential drop created by the resistor R1 which is, remember, proportional to the current produced by the diode D3, is lower than the potential of the capacitor C3. As a result, the current generator formed by said diode D3 and the transistor T1 can not recharge the capacitor C3. This will only be possible again when the capacitor C3 has sufficiently discharged and its potential will fall below the potential present across the resistor R1. Thus, the fluctuations in the voltage across the capacitor C3 are a faithful reflection of the variations in the intensity of the ambient lighting.

Comme on peut le voir sur la figure 1 annexée à la présente demande de brevet, le circuit RC formé par le condensateur C3 et la résistance R9 est relié à l'entrée logique D d'une bascule 1. Cette bascule 1 constitue un étage qui, lorsqu'un signal destiné à commander l'allumage de la source lumineuse est produit, adapte l'intensité de la lumière fournie par ladite source lumineuse en fonction de l'état électrique stocké dans l'étage de mémorisation. Plus précisément, cette bascule 1 va considérer que son entrée D est à un niveau logique haut "1" ou bas "0" selon que la tension appliquée sur cette entrée est supérieure à une première valeur donnée, par exemple 1,7 volts, ou inférieure à une seconde valeur donnée, par exemple 1,2 volts. De façon classique, la bascule 1 a pour fonction d'appliquer sans modification l'état logique dans lequel se trouve son entrée D à sa sortie Q sous l'effet d'une sollicitation extérieure. Dans le cas de la présente invention, cette sollicitation extérieure revêt la forme d'une pression sur un bouton-poussoir PB1 qui vient mettre à l'instant t1 (voir figure 2, courbe "start") la sortie Q d'un circuit de temporisation 2 à un niveau haut "1". Comme on peut le voir sur le schéma électrique, la sortie Q du temporisateur 2 est reliée directement à l'entrée horloge CLK de la bascule 1. Ainsi, lorsqu'on appuie sur le poussoir PB1 à l'instant t1, on enclenche le circuit de temporisation 2, ce qui a pour effet de faire basculer l'état logique dans lequel se trouve l'entrée D de la bascule 1 vers la sortie Q de ce dernier, et de maintenir ladite sortie Q dans cet état pendant une certaine durée après l'actionnement du poussoir PB1. Cette durée est imposée par le temporisateur 2 et correspond à l'intervalle de temps t1-t3 sur la courbe "tempo" de la figure 2. L'état de la sortie Q de la bascule 1 est donc l'image des conditions d'éclairement ambiant au moment où l'on a actionné le bouton-poussoir PB1.As can be seen on the figure 1 attached to the present patent application, the RC circuit formed by the capacitor C3 and the resistor R9 is connected to the logic input D of a flip-flop 1. This flip-flop 1 constitutes a stage which, when a signal intended to control the ignition of the light source is produced, adapts the intensity of the light supplied by said light source according to the electrical state stored in the storage stage. More precisely, this flip-flop 1 will consider that its input D is at a logic high level "1" or low "0" depending on whether the voltage applied to this input is greater than a first given value, for example 1.7 volts, or less than a second given value, for example 1.2 volts. Conventionally, the flip-flop 1 has the function of applying, without modification, the logic state in which its input D is located at its output Q under the effect of an external bias. In the case of the present invention, this external stress takes the form of a pressure on a push button PB1 which just put t1 (see figure 2 , "start" curve) the output Q of a timing circuit 2 at a high level "1". As can be seen in the wiring diagram, the output Q of the timer 2 is connected directly to the clock input CLK of the flip-flop 1. Thus, when the pusher PB1 is pressed at the instant t1, the circuit is switched on. 2, which has the effect of switching the logic state in which the input D of the flip-flop 1 to the Q output of the latter is located, and of keeping said output Q in this state for a certain period of time after the actuation of the pusher PB1. This duration is imposed by the timer 2 and corresponds to the time interval t1-t3 on the curve "tempo" of the figure 2 . The state of the output Q of the flip-flop 1 is therefore the image of the conditions of ambient illumination at the moment when the push-button PB1 was actuated.

La sortie Q du temporisateur 2 est également reliée à la grille du transistor T2. Comme on l'a déjà mentionné précédemment, le transistor T2 est conducteur pendant toute la durée de la phase de veille du dispositif selon l'invention, et le condensateur C3 est relié au générateur de courant formé par la diode électroluminescente D3 et le transistor T1 par l'intermédiaire de la diode anti-retour D1 et dudit transistor T2. Par contre, dès que la diode D3 n'est plus utilisée comme capteur de l'intensité lumineuse environnante mais comme source d'éclairement, il faut immédiatement découpler l'étage de mémorisation (condensateur C3, résistance R9) de l'étage de mesure ou d'intégration (diode D3, transistor T1, résistance R1 ) afin de ne pas fausser l'état de charge dudit condensateur C3. Tel est le rôle du signal généré à la sortie Q du temporisateur 2 qui vient ouvrir le transistor T2.The Q output of timer 2 is also connected to the gate of transistor T2. As already mentioned above, the transistor T2 is conducting throughout the duration of the idle phase of the device according to the invention, and the capacitor C3 is connected to the current generator formed by the light emitting diode D3 and the transistor T1 via the non-return diode D1 and said transistor T2. On the other hand, as soon as the diode D3 is no longer used as a sensor of the surrounding light intensity but as a source of illumination, the storage stage (capacitor C3, resistor R9) of the measurement stage must be decoupled immediately. or integration (diode D3, transistor T1, resistor R1) so as not to distort the state of charge of said capacitor C3. This is the role of the signal generated at the output Q of the timer 2 which opens the transistor T2.

Quand on appuie sur le bouton-poussoir PB1 pour commander l'allumage de la diode électroluminescente D3, ceci a pour effet de mettre à "1" la sortie logique Q du temporisateur 2. Par suite, on transfère l'état logique de l'entrée D de la bascule 1 vers sa sortie Q et on ouvre le transistor T2 afin d'isoler le condensateur C3 du générateur de courant formé par la diode D3 et le transistor T1 et commandé par le degré de luminosité ambiant. En même temps, le niveau haut de la sortie logique Q du temporisateur 2 est appliqué à la grille d'un transistor T3 pour rendre ce dernier conducteur et permettre l'alimentation de la diode D3 en énergie électrique. Toutefois, le transistor T3 qui commande l'éclairage est rendu passant à l'instant t2 seulement (voir figure 2 courbe "LED"), c'est-à-dire avec un petit temps de retard sur l'instant t1 où l'on actionne le bouton-poussoir PB1. Ce retard est introduit par un circuit RC constitué d'un condensateur C1 et d'une résistance R3 disposés entre le temporisateur 2 et le transistor T3. Cet allumage différé de la diode D3 permet de s'assurer que l'on ne vient pas modifier l'état de la charge électrique accumulée dans le condensateur C3.When the push button PB1 is pressed to control the lighting of the LED D3, this has the effect of setting the logic output Q of the timer 2 to "1". As a result, the logic state of the input D of the flip-flop 1 to its Q output and the transistor T2 is opened to isolate the capacitor C3 of the current generator formed by the diode D3 and the transistor T1 and controlled by the degree of ambient brightness. At the same time, the high level of the logic output Q of the timer 2 is applied to the gate of a transistor T3 to make the latter conductive and allow the diode D3 to be supplied with electrical energy. However, the transistor T3 controlling the lighting is turned on at time t2 only (see figure 2 curve "LED"), that is to say with a small delay time t1 moment where the push button PB1 is actuated. This delay is introduced by an RC circuit consisting of a capacitor C1 and a resistor R3 arranged between the timer 2 and the transistor T3. This delayed ignition of the diode D3 makes it possible to ensure that the state of the electric charge accumulated in the capacitor C3 is not changed.

Le niveau logique haut ou bas de la sortie Q de la bascule 1 est représenté sur la courbe "ligthing" de la figure 2. Deux traits gras horizontaux indiquent l'état logique "0" ou "1" de la sortie Q de la bascule 2. L'état logique de la sortie Q est fonction de l'état de charge du condensateur C3 à l'instant t1 où l'on appuie sur le bouton-poussoir PB1. En effet, aussi longtemps que la diode D3 fonctionne comme capteur, la tension aux bornes du condensateur C3 fluctue en fonction des variations de l'intensité de la lumière environnante (voir figure 2, courbe "Vlight"). A l'instant t1 où l'on appuie sur le poussoir PB1, l'état de charge du condensateur C3 se fige et reste sensiblement le même pendant toute la durée de la temporisation, bien que les conditions d'éclairement puissent continuer à fluctuer comme cela est indiqué en pointillés sur la courbe "Vlight" de la figure 2. Effectivement, en raison de sa constante de temps, le condensateur C3 se décharge lentement en comparaison avec la durée du signal de temporisation qui correspond à la durée pendant laquelle la diode électroluminescente D3 reste allumée. A la fin de la temporisation, le condensateur C3 est à nouveau alimenté et retrouve rapidement un niveau de charge correspondant aux conditions d'éclairement ambiant.The logical high or low level of the Q output of flip-flop 1 is represented on the "ligthing" curve of the figure 2 . Two horizontal bold lines indicate the logic state "0" or "1" of the Q output of flip-flop 2. The logic state of output Q is a function of the state of charge of capacitor C3 at time t1 where push button PB1 is pressed. Indeed, as long as the diode D3 functions as a sensor, the voltage across the capacitor C3 fluctuates as a function of the variations in the intensity of the surrounding light (see FIG. figure 2 curve "Vlight"). At time t1 when the pushbutton PB1 is pressed, the state of charge of the capacitor C3 freezes and remains substantially the same throughout the duration of the time delay, although the illumination conditions can continue to fluctuate as this is indicated in dashed lines on the "Vlight" curve of the figure 2 . Indeed, because of its time constant, the capacitor C3 slowly discharges in comparison with the duration of the delay signal which corresponds to the duration during which the light emitting diode D3 remains on. At the end of the delay, the capacitor C3 is powered again and quickly regains a charge level corresponding to ambient lighting conditions.

Le niveau logique haut ou bas de la sortie Q de la bascule 1 est appliqué sur la grille d'un transistor T6. Par suite, si la sortie Q de la bascule 1 est dans l'état logique "0", le transistor T6 reste ouvert et la diode D3 est alimentée avec un courant minimum à travers deux résistances R4 et R5 montées en série entre ladite diode D3 et ledit transistor T6. Par contre, si la sortie Q de la bascule 1 est dans l'état logique "1", le transistor T6 se ferme et la diode D3 est alors alimentée avec un courant maximum à travers la seule résistance R5. En effet, lorsque le transistor T6 est conducteur, il court-circuite pratiquement la résistance R4 dans la mesure où la valeur de sa résistance interne est très faible au regard de celle de R4.The logic high or low level of the Q output of flip-flop 1 is applied to the gate of a transistor T6. As a result, if the Q output of the flip-flop 1 is in logic state "0", the transistor T6 remains open and the diode D3 is supplied with a minimum current through two resistors R4 and R5 connected in series between said diode D3. and said transistor T6. On the other hand, if the output Q of the flip-flop 1 is in the logic state "1", the transistor T6 closes and the diode D3 is then supplied with a maximum current through the single resistor R5. Indeed, when the transistor T6 is conductive, it virtually bypasses the resistance R4 insofar as the value of its internal resistance is very small compared to that of R4.

A la fin de la temporisation, l'état logique de la sortie Q du temporisateur repasse à "0". Aussitôt, le transistor T3 s'ouvre, provoquant l'extinction de la diode D3. De même, le transistor T2 se ferme à nouveau, de sorte que le condensateur C3 est à nouveau relié à l'étage source de courant formé par la diode D3 et le transistor T1 et que son état de charge retrouve progressivement un niveau correspondant à l'intensité de la luminosité ambiante. Enfin, un second timer 4 vient remettre à zéro la sortie logique Q de la bascule 1 (voir figure 2, courbe "reset").At the end of the delay, the logic state of the Q output of the timer returns to "0". Immediately, the transistor T3 opens, causing the extinction of the diode D3. Similarly, the transistor T2 closes again, so that the capacitor C3 is again connected to the current source stage formed by the diode D3 and the transistor T1 and that its state of charge gradually returns to a level corresponding to the intensity of the ambient light. Finally, a second timer 4 resets the logic output Q of the flip-flop 1 (see FIG. figure 2 , "reset" curve).

On va maintenant examiner un cycle de fonctionnement du dispositif selon l'invention. On suppose, pour commencer, que le dispositif se trouve en état de veille, c'est-à-dire dans un état où la diode électroluminescente D3 n'éclaire pas mais est seulement utilisée pour détecter le degré d'intensité de la luminosité ambiante. On suppose par ailleurs qu'au début de ce cycle de fonctionnement, le dispositif se trouve dans la clarté.We will now examine a cycle of operation of the device according to the invention. It is assumed, for a start, that the device is in a standby state, that is to say in a state where the light-emitting diode D3 does not light but is only used to detect the degree of intensity of the ambient light. . It is also assumed that at the beginning of this operating cycle, the device is in clarity.

En état de veille du dispositif, le transistor T3 est ouvert car la diode électroluminescente D3 ne doit pas être alimentée électriquement. A l'inverse, le transistor T2 est fermé et donc passant de façon que la tension présente aux bornes de la résistance R1 puisse être appliquée aux bornes du condensateur C3 et permette ainsi la charge de ce dernier. On rappelle que la tension aux bornes de la résistance R1 résulte du courant qui traverse celle-ci et qui est produit par la diode électroluminescente D3 et le transistor T1 fonctionnant comme un générateur de courant commandé par la luminosité ambiante. On comprend sans peine que l'état de charge du condensateur C3 est fonction de la chute de potentiel au point commun entre le drain du transistor T1 et la résistance R1. Ainsi, la valeur de la résistance R1 va déterminer la valeur de la tension appliquée à l'entrée logique D de la bascule 1 et permettre à cette dernière de décider si son entrée logique D est à un niveau haut "1" ou bas "0". Selon que l'entrée logique D de la bascule 1 se trouvera à "0" ou à "1" au moment où le bouton-poussoir PB1 sera actionné, cela déterminera l'intensité du courant électrique alimentant la diode D3 et donc l'intensité, faible ou élevée, de l'éclairement produit par ladite diode D3.In the standby state of the device, the transistor T3 is open because the light-emitting diode D3 must not be electrically powered. Conversely, the transistor T2 is closed and thus passing so that the voltage present across the resistor R1 can be applied across the capacitor C3 and thus allows the load of the latter. It is recalled that the voltage across the resistor R1 results from the current flowing through it and which is produced by the light emitting diode D3 and the transistor T1 operating as a current generator controlled by the ambient brightness. It is easy to understand that the state of charge of the capacitor C3 is a function of the potential drop at the common point between the drain of the transistor T1 and the resistor R1. Thus, the value of the resistor R1 will determine the value of the voltage applied to the logic input D of the flip-flop 1 and allow it to decide whether its logic input D is at a high level "1" or low "0 ". Depending on whether the logic input D of flip-flop 1 is at "0" or "1" at the moment when the push-button PB1 is actuated, this will determine the intensity of the electric current supplying the diode D3 and therefore the intensity low or high, the illumination produced by said diode D3.

Le dispositif selon l'invention se trouvant dans la clarté, supposons que l'on actionne le bouton-poussoir PB1. L'état de charge du condensateur C3 se trouve à un niveau élevé, de sorte que l'état logique de l'entrée D de la bascule 1 se trouve à son niveau haut "1". Sous l'effet de l'actionnement du bouton-poussoir PB1, la sortie Q du circuit de temporisation 2 passe à "1" et commande le transfert de l'état logique "1" de l'entrée D de la bascule 1 vers la sortie Q de cette dernière. Simultanément, le circuit de temporisation 2 commande l'ouverture du transistor T2 afin que l'état de charge du condensateur C3 ne soit pas faussé par l'allumage de la diode électroluminescente D3. De même, le circuit de temporisation 2 commande la fermeture du transistor T3 afin que la diode D3 puisse être alimentée en courant électrique. La diode D3 n'est cependant alimentée qu'un bref instant après que l'on ait actionné le poussoir PB1, ce retard étant généré par un circuit RC qui se compose d'un condensateur C1 et d'une résistance R3 et permettant, là aussi, de s'assurer que l'état de la charge du condensateur C3 ne va pas être modifié par l'allumage de la diode D3. Enfin, le niveau haut "1" de la sortie Q de la bascule 2 est appliqué à la grille du transistor T6 afin de rendre ce dernier conducteur, de sorte que le courant qui va alimenter la diode D3 est limité seulement par la résistance R5. L'éclairage de la diode D3 va donc être maximum. Cette fonction est surtout utile lorsqu'un vendeur d'un magasin de joaillerie souhaite présenter à un client l'aspect que présente la montre lorsqu'on l'éclaire dans la pénombre. En effet, malgré la clarté qui règne dans le point de vente, la diode D3 brillera suffisamment fort pour que le client puisse percevoir l'éclairage de ladite montre. Au bout d'un certain temps de fonctionnement de la diode D3 qui est déterminé par le circuit de temporisation 2, la sortie logique Q dudit temporisateur 2 passe à zéro. Aussitôt, le transistor T3 s'ouvre, provoquant l'extinction de la diode D3, et le transistor T2 se ferme, de sorte que le condensateur C3 retrouve progressivement un état de charge correspondant à la luminosité ambiante.The device according to the invention being in the light, suppose that one actuates the push button PB1. The state of charge of the capacitor C3 is at a high level, so that the logic state of the input D of the flip-flop 1 is at its high level "1". Under the effect of the actuation of the push button PB1, the output Q of the timing circuit 2 goes to "1" and controls the transfer of the logic state "1" of the input D of the flip-flop 1 to the Q output of the latter. Simultaneously, the timing circuit 2 controls the opening of the transistor T2 so that the state of charge of the capacitor C3 is not distorted by the ignition of the light-emitting diode D3. Similarly, the timing circuit 2 controls the closing of the transistor T3 so that the diode D3 can be supplied with electric current. The diode D3, however, is energized only briefly after the pusher PB1 has been actuated, this delay being generated by an RC circuit which consists of a capacitor C1 and a resistor R3 and allowing, there also, to ensure that the state of the charge of the capacitor C3 will not be changed by the ignition of the diode D3. Finally, the high level "1" of the Q output of the flip-flop 2 is applied to the gate of the transistor T6 to make the latter conductive, so that the current that will feed the diode D3 is limited only by the resistor R5. The lighting of the diode D3 will therefore be maximum. This function is especially useful when a seller of a jewelry store wishes to present to a customer the appearance of the watch when illuminated in dim light. Indeed, despite the clarity that prevails in the point of sale, the diode D3 shine bright enough for the customer to perceive the lighting of said watch. After a certain operating time of the diode D3 which is determined by the timing circuit 2, the logic output Q of said timer 2 goes to zero. Immediately, the transistor T3 opens, causing the extinction of the diode D3, and the transistor T2 closes, so that the capacitor C3 gradually returns to a state of charge corresponding to the ambient brightness.

Supposons maintenant que l'utilisateur passe subitement d'un environnement clair à un environnement où règne la pénombre et qu'il souhaite consulter sa montre. En passant d'un endroit fortement éclairé à un endroit qui l'est moins, le dispositif selon l'invention va se trouver dans une situation dans laquelle la chute de potentiel créée par la résistance R1 qui est fonction du degré d'intensité de la luminosité ambiante va être inférieure au potentiel du condensateur C3. En conséquence, le générateur de courant formé par la diode photoluminescente D3 et le transistor T1 ne peut pas recharger le condensateur C3 et ce dernier va commencer à se décharger progressivement à travers la résistance R9. La vitesse à laquelle le condensateur C3 se décharge est fixée par la constante de temps du circuit constitué par ledit condensateur C3 et la résistance R9. Il s'agit d'un paramètre que l'on peut ajuster en fonction des valeurs de C3 et de R9.Suppose now that the user suddenly switches from a clear environment to a dark environment and wants to see his watch. By passing from a strongly illuminated place to one which is less so, the device according to the invention will be in a situation in which the potential drop created by the resistance R1 which is a function of the degree of intensity of the Ambient brightness will be less than the potential of capacitor C3. As a result, the current generator formed by the photoluminescent diode D3 and the transistor T1 can not recharge the capacitor C3 and the latter will begin to gradually discharge through the resistor R9. The rate at which the capacitor C3 discharges is set by the time constant of the circuit constituted by said capacitor C3 and the resistor R9. This is a parameter that can be adjusted according to the values of C3 and R9.

Conformément à l'invention, la valeur de la constante de temps du circuit C3, R9 sera de l'ordre de quelques minutes. Il s'agit en effet d'une durée qui correspond au temps moyen nécessaire à l'oeil humain pour s'accoutumer à l'obscurité lorsque la personne vient d'un milieu fortement éclairé. Ainsi, si l'utilisateur actionne le bouton-poussoir PB1 avant que l'état de charge du condensateur C3 n'ait atteint la valeur de la chute de potentiel au point commun entre le transistor T1 et la résistance R1, l'état de l'entrée logique D de la bascule 1 sera haut et la diode D3 brillera fortement. Si, au contraire, l'utilisateur actionne le poussoir PB1 alors que le condensateur C3 s'est déchargé à travers la résistance R9 et que la tension à ses bornes correspond à la tension aux bornes de la résistance R1, dans ce cas l'état de l'entrée logique D de la bascule 1 sera bas et la diode électroluminescente D3 brillera faiblement. Cette caractéristique de l'invention permet avantageusement à l'utilisateur de pouvoir lire les indications fournies par sa montre dans toutes les circonstances. Ainsi, si l'utilisateur passe brusquement de la clarté à la pénombre et qu'il actionne peu de temps après le bouton-poussoir PB1, la diode électroluminescente D3 brillera fortement pour lui permettre de lire les informations affichées par sa montre car sa vision ne se sera pas encore accoutumée pleinement à l'obscurité. Par contre, s'il se déroule un temps plus long entre le moment où l'utilisateur pénètre dans l'obscurité et le moment où celui-ci veut consulter sa montre, l'intensité de l'éclairage fourni par la diode D3 sera faible. En effet, les yeux de l'utilisateur auront eu le temps de s'habituer à la vision de nuit et il ne sera donc plus nécessaire d'éclairer fortement la montre. Ceci présent un double avantage; d'une part, l'utilisateur n'est pas ébloui lorsqu'il consulte sa montre, par exemple durant la nuit, et d'autre part on réalise des économies d'énergie substantielles.According to the invention, the value of the time constant of the circuit C3, R9 will be of the order of a few minutes. It is indeed a duration which corresponds to the average time necessary for the human eye to accustom itself to the darkness when the person comes from a strongly lit environment. Thus, if the user actuates the push-button PB1 before the state of charge of the capacitor C3 has reached the value of the potential drop at the common point between the transistor T1 and the resistor R1, the state of the logic input D of flip-flop 1 will be high and diode D3 will shine strongly. If, on the contrary, the user actuates the pusher PB1 while the capacitor C3 has discharged through the resistor R9 and the voltage at its terminals corresponds to the voltage across the resistor R1, in this case the state the logic input D of the flip-flop 1 will be low and the light-emitting diode D3 will glow weakly. This feature of the invention advantageously allows the user to read the indications provided by his watch in all circumstances. Thus, if the user suddenly switches from lightness to dim light and it operates shortly after the pushbutton PB1, the light-emitting diode D3 will shine strongly to allow him to read the information displayed by his watch because his vision will not be fully accustomed to the darkness. On the other hand, if a longer time elapses between the moment when the user enters the darkness and the moment when the user wants to consult his watch, the intensity of the illumination provided by the diode D3 will be weak. . Indeed, the user's eyes have had time to get used to the night vision and it will no longer be necessary to strongly illuminate the watch. This presents a double advantage; on the one hand, the user is not dazzled when consulting his watch, for example during the night, and secondly realizes substantial energy savings.

Il faut enfin examiner le cas où l'on passe rapidement de la pénombre à la lumière. Dans ce dernier cas, le condensateur atteint quasi-instantanément via le transistor T2 un état de charge correspondant à une forte illumination, de sorte que si l'utilisateur actionne le bouton-poussoir PB1, l'entrée logique D de la bascule 1 se trouve à un niveau haut "1" correspondant au cas où la diode électroluminescente D3 procure un éclairement intense.Finally, we must examine the case where we quickly move from darkness to light. In the latter case, the capacitor reaches almost instantaneously via the transistor T2 a charge state corresponding to a strong illumination, so that if the user actuates the push button PB1, the logic input D of the flip-flop 1 is located at a high level "1" corresponding to the case where the light emitting diode D3 provides intense illumination.

Il va de soi que la présente invention n'est pas limitée aux modes de réalisation qui viennent d'être décrits, et que diverses modifications et variantes simples peuvent être envisagées sans sortir du cadre de la présente invention. En particulier, on peut envisager que les valeurs des résistances puissent être programmées par l'utilisateur afin de régler les temps de charge et de décharge des condensateurs et donc les temps d'adaptation de l'éclairage aux conditions de vision diurnes et nocturnes. Un autre mode de réalisation avantageux consiste à utiliser à utiliser un circuit électronique qui illumine une cellule à cristal liquide de façon pulsée pour améliorer la lisibilité et le contraste de l'affichage. En effet, si l'on mesure le contraste de l'affichage d'une cellule à cristal liquide intégrée dans une montre, on constate un battement de ce contraste synchronisé avec le signal d'adressage des électrodes de ladite cellule. Ainsi, si l'on synchronise l'illumination pulsée avec l'adressage de la cellule à cristal liquide de façon optimisée, l'observateur n'apercevra que le contraste d'affichage maximal.It goes without saying that the present invention is not limited to the embodiments that have just been described, and that various modifications and simple variants can be envisaged without departing from the scope of the present invention. In particular, it can be envisaged that the values of the resistors can be programmed by the user in order to adjust the charging and discharging times of the capacitors and thus the adaptation times of the illumination to the day and night vision conditions. Another advantageous embodiment is to use an electronic circuit that pulses a liquid crystal cell to improve the readability and contrast of the display. Indeed, if one measures the contrast of the display of a liquid crystal cell integrated in a watch, there is a beat of this contrast synchronized with the addressing signal of the electrodes of said cell. Thus, if the pulsed illumination is synchronized with the addressing of the liquid crystal cell in an optimized manner, the observer will only perceive the maximum display contrast.

Claims (24)

  1. Lighting device for an electronic or electromechanical apparatus such as a timepiece of the wristwatch type including a display device for time-related or other data, this lighting device including a light source (D3) for lighting the display device, said lighting source (D3) being also able to measure the intensity of the ambient light, said lighting device including:
    - a measurement stage (D3, T1) arranged to provide an electric signal representative of the ambient lighting conditions;
    - a memory stage (C3, R9) arranged to store an electric state corresponding to a low or strong luminosity level as a function of the electric signal generated by the measurement stage, said memory stage including a capacitor (C3) connected in parallel to the terminals of a resistor (R9) so as to form an RC circuit whose time constant value is adjusted as a function of the capacitance values of the capacitor (C3) and the resistor (R9), and
    - a stage (1) which, when a signal (Tempo) ordering the light source to be switched on is produced, is arranged to adapt the intensity of the light provided by said light source (D3) as a function of the electric state stored in the memory stage (C3, R9),
    switching means (T2) being arranged between the measurement stage and the memory stage, these switching means being conductive as long as the light source measures the ambient light intensity, and being non conductive upon reception of said signal ordering the light source (D3) to be switched on in order to avoid disturbing the state of charge of said memory stage.
  2. Lighting device according to claim 1, characterized in that the light intensity provided by the light source is a function of the intensity of the measured ambient light.
  3. Lighting device according to any of claims 1 or 2, characterized in that the light source is able to measure the degree of ambient luminosity intensity during periods in which it is not used for lighting.
  4. Lighting device according to any of claims 1 to 3, characterized in that the measurement stage includes the light source associated with a transistor (T1) so as to form a current generator controlled by the ambient light intensity.
  5. Lighting device according to any of claims 1 to 4, characterized in that the time constant value corresponds to the time necessary for the human eye to become accustomed to the dark.
  6. Lighting device according to any of claims 1 to 5, characterized in that the circuit controlling the switching on of the light source includes a flip flop (1) mounted following the circuit formed by the capacitor (C3) and the resistor (R9), the high or low state of a logic input D of the flip flop (1) being a function of the state of charge of the capacitor (C3), this state being transferred to a logic output Q of the same flip flop (1) upon reception of the control signal ordering the light source to be switched on, the output Q of said flip flop (1) then controlling means capable of powering the light source with a stronger or weaker current depending upon whether the logic state of said output Q is high or low.
  7. Lighting device according to claim 6, characterized in that the means for controlling the intensity of the current powering the light source include at least two series connected resistors (R4, R5), one of which (R4) is capable of being shortcircuited by a transistor (T6) arranged across its terminals when the latter is made conductive.
  8. Lighting device according to any of claims 6 or 7, characterized in that the control signal is generated by a timing circuit (2), this timing circuit (2) ordering closure of switching means for connecting the light source to a power source and determining the time during which said light source will remain switched on.
  9. Lighting device according to claim 8, characterized in that the switching means include a second transistor (T3).
  10. Lighting device according to any of claims 8 or 9, characterized in that the light source is powered with a timing with respect to the transmission of the control signal for switching on said light source.
  11. Lighting device according to claim 10, characterized in that the timing is generated by a second RC circuit including a second capacitor (C1) and a second resistor (R3).
  12. Lighting device according to any of claims 1 to 11, characterized in that the memory stage is separated from the measurement stage by an anti-return diode (D1) preventing the capacitor (C3) from discharging into said measurement stage.
  13. Lighting device according to any of claims 1 to 12, characterized in that the switching means include a third transistor (T2).
  14. Lighting device according to any of claims 6 to 13, characterized in that when the light source is switched off, a second timing circuit (14) resets the logic output Q of the flip flop (1) to zero.
  15. Lighting device according to any of claims 1 to 14, characterized in that the light source is a light emitting diode (D3).
  16. Lighting device according to any of claims 1 to 15, characterized in that the display device includes a liquid crystal cell, a dial or hands or a combination of at least two of these elements.
  17. Lighting device according to any of claims 1 to 16, characterized in that the lighting device can be used in combination with optical elements used to distribute the light produced by the light source over the lighting device assembly.
  18. Lighting method for a device displaying time-related or other information for an electronic or electromechanical apparatus, such as a timepiece of the wristwatch type, including a light source (D3) for lighting the display device, said light source being also used for measuring the intensity of the ambient light, this method including the steps of:
    - measuring the ambient lighting conditions and providing an electric signal representative of these ambient lighting conditions;
    - storing an electric state corresponding to a low or strong luminosity level as a function of the electric signal provided during the measurement step of the ambient lighting conditions by means of a storing stage including a capacitor (C3) connected in parallel to the terminals of a resistor (R9) so as to form an RC circuit whose time constant value is adjusted as a function of the capacitance values of the capacitor (C3) and the resistor (R9), and
    - adapting the intensity of the light provided by said light source (D3) as a function of the electric state stored when a signal (Tempo) intended to order the lighting of the light source is produced,
    the method further comprising the step of keeping conductive switching means (T2) arranged between measurement means (D3, T1) of the ambient lighting conditions and storing means (C3, R9) of the level of ambient lighting as long as the light source measures the ambient light intensity, and to interrupt the connexion between the measuring means (D3, T1) and the storing means (C3, R9) upon reception of said signal ordering the lighting of the light source (D3) in order to avoid disturbing the state of charge of said memory means.
  19. Method according to claim 18, characterized in that the display device is illuminated more or less intensely as a function of the degree of ambient luminosity.
  20. Method according to claim 19, characterized in that the display device is brightly lit if it is in an illuminated environment.
  21. Method according to any of claims 18 to 20, characterized in that, if the apparatus is passed from a brightly lit environment to an environment in semi-darkness or darkness, and one wishes to light the display device before reaching the moment at which the human eye has become accustomed to the darkness, the display device is lit with the same intensity as if it were in a lit environment.
  22. Method according to any of claims 18 to 21, characterized in that, if the apparatus is passed from a brightly lit place to a place in semi-darkness or darkness and one wishes to light the display device after having reached the moment when the human eye has become accustomed to the dark, the display device is weakly lit.
  23. Method according to any of claim 18 to 22, characterized in that the times for adapting the lighting to day and night vision conditions can be programmed.
  24. Method according to any of claims 18 to 23 wherein the display device is a liquid crystal cell, characterized in that illumination is synchronised with the liquid crystal cell display frequency, so as to light said cell at the moment when its contrast is optimum.
EP02075879A 2002-03-05 2002-03-05 Method and means for illuminating an electronic or an electromechanical device Expired - Lifetime EP1343059B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP02075879A EP1343059B1 (en) 2002-03-05 2002-03-05 Method and means for illuminating an electronic or an electromechanical device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP02075879A EP1343059B1 (en) 2002-03-05 2002-03-05 Method and means for illuminating an electronic or an electromechanical device

Publications (2)

Publication Number Publication Date
EP1343059A1 EP1343059A1 (en) 2003-09-10
EP1343059B1 true EP1343059B1 (en) 2011-12-21

Family

ID=27741209

Family Applications (1)

Application Number Title Priority Date Filing Date
EP02075879A Expired - Lifetime EP1343059B1 (en) 2002-03-05 2002-03-05 Method and means for illuminating an electronic or an electromechanical device

Country Status (1)

Country Link
EP (1) EP1343059B1 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107241827B (en) * 2017-06-07 2023-09-12 欧普照明股份有限公司 Switching circuit

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3757511A (en) * 1971-05-17 1973-09-11 Motorola Inc Light emitting diode display for electronic timepiece
JPH02107991A (en) * 1988-10-17 1990-04-19 Seikosha Co Ltd Clock with light-emitting device
FI110211B (en) * 1999-12-31 2002-12-13 Nokia Corp Measurement of lighting conditions

Also Published As

Publication number Publication date
EP1343059A1 (en) 2003-09-10

Similar Documents

Publication Publication Date Title
US7550930B2 (en) Method and device for lighting an electronic or electromechanical apparatus
CH616822B5 (en)
FR2463470A1 (en) LIQUID CRYSTAL DISPLAY UNIT FOR MOTOR VEHICLES
FR2783629A1 (en) Active matrix liquid crystal display (LCD) apparatus has gate driver with shift register that receives at least two voltages and outputs, one of the voltages driving pixels
FR2752070A1 (en) ELECTRONIC WATCH PIECE COMPRISING A GENERATOR DRIVEN BY A SPRING BARREL
EP1875454B1 (en) Circuit and method for controlling a liquid crystal segment display
EP0744675B1 (en) Time measuring instrument particularly electric wrist watch of the analogue type
EP3620866B1 (en) Active lighting device for wearing on the wrist of a person
EP1343059B1 (en) Method and means for illuminating an electronic or an electromechanical device
EP2904927A1 (en) Container interacting with a user with reduced power consumption prior to unpacking
EP2746869A1 (en) Solar electric winding for automatic watch
EP0221363B1 (en) Analogous electronic watch
EP3835890B1 (en) Device for digital display comprising two overlapping display cells
WO1998033098A1 (en) Watch comprising sensing and saving means in case of insufficiency of supply source
CH716362B1 (en) A digital display device comprising two superimposed display cells and a timepiece comprising such a display device.
CH621027B5 (en)
EP0243232A1 (en) Device for driving a mobile
FR2846479A1 (en) Circuit for detecting state of switches, comprises micro-controller linked by digital command to starting entries of state detection unit with sensors connected to communication contacts of switches
CH715296A2 (en) Portable active lighting device on a person's wrist.
FR2553509A3 (en) MEASURING DEVICE COMPRISING A PASSIVE DISPLAY DEVICE
FR2476341A1 (en) Battery-powered alarm clock - has battery connected by controller to gating system and sounds alarm when battery is exhausted
CH712944A2 (en) Two-needle electronic timepiece of the analog type.
CH720364A2 (en) Watch dial comprising an autonomous device for determining a magnetic event
CH715991A2 (en) Electronic timepiece with motion detector.
EP3299906A1 (en) Analogue electronic timepiece with two needles

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

AX Request for extension of the european patent

Extension state: AL LT LV MK RO SI

17P Request for examination filed

Effective date: 20040310

AKX Designation fees paid

Designated state(s): CH DE FR GB LI

RBV Designated contracting states (corrected)

Designated state(s): AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR

RBV Designated contracting states (corrected)

Designated state(s): CH DE FR GB LI

17Q First examination report despatched

Effective date: 20100118

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

RTI1 Title (correction)

Free format text: METHOD AND MEANS FOR ILLUMINATING AN ELECTRONIC OR AN ELECTROMECHANICAL DEVICE

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): CH DE FR GB LI

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: CH

Ref legal event code: NV

Representative=s name: ICB INGENIEURS CONSEILS EN BREVETS SA

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 60241777

Country of ref document: DE

Effective date: 20120308

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed

Effective date: 20120924

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20120321

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 60241777

Country of ref document: DE

Effective date: 20120924

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20120321

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20160218

Year of fee payment: 15

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20160219

Year of fee payment: 15

REG Reference to a national code

Ref country code: DE

Ref legal event code: R119

Ref document number: 60241777

Country of ref document: DE

REG Reference to a national code

Ref country code: CH

Ref legal event code: PFUS

Owner name: THE SWATCH GROUP RESEARCH AND DEVELOPMENT LTD , CH

Free format text: FORMER OWNER: ASULAB S.A., CH

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

Effective date: 20171130

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20171003

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20170331

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: CH

Payment date: 20210219

Year of fee payment: 20

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL