EP1315404A1 - Illuminated display device for displaying the operating state of a system, in particular for avionics - Google Patents

Abstract

The device has a set of lights (29) and a detection unit that checks for failure of the lights. Each light has m branches (31) with n serially connected light emitting diodes (32) in each branch. The inputs of the diodes are parallel connected and the outputs are connected to a selector (33). The selector connects the selected branch to the output terminal upon receiving signal from a controller (41). <??>An Independent claim is also included for a process for management of a light signaling device related to the operating state of a system.

Description

TECHNICAL AREA

The present invention relates to a light information device concerning the state of operation of a system and a management method such a device, particularly in the field of avionics.

STATE OF THE PRIOR ART

To simplify the description, we will consider in the following, as an example, a implementation of the invention in the avionics field.

Currently many indicators of signaling type lights, for example electroluminescent diodes, are used in cockpits of planes to inform pilots, possibly maintenance operators, states of the various systems present in these planes.

The loss of information delivered by a such an indicator, mainly in operation operational, can be tricky or even dangerous.

The pilots are therefore led to check regularly the good working order of such indicators via a test command which has the effect of lighting up a pre-determined set of these, for example those of the ceiling panel. The drivers must then change the faulty LEDs to line.

Thus, as illustrated in Figure 1, in a signaling assembly consisting of several LEDs 10 controlled by signals SV1, SV2, SV3, at through diodes 11, a command button 12 causes the simultaneous lighting of all these lights and allows the pilot to easily spot a light that remains off.

• une consommation importante pendant le test, surtout lorsque ces voyants sont des lampes à incandescence,
• une impossibilité de détecter un voyant tombé en panne postérieurement au test,
• une efficacité du test reposant sur la vigilance de l'opérateur.

Such a set has many disadvantages, and in particular:

• a significant consumption during the test, especially when these lights are incandescent lamps,
• an impossibility of detecting a light that has failed after the test,
• an effectiveness of the test based on the vigilance of the operator.

Replacement of incandescent lamps by light-emitting diodes allowed to increase the life of such indicators.

It is also known to use indicators each consisting of several elements light emitter 20 in series / parallel assembly, as shown in Figure 2. The failure of an element 20 then does not cause the LED to fail but a simple drop in brightness. Such a device is not not really fault tolerant but presents a degraded operating mode in case of failure.

The subject of the invention is a device of light information of the operating state a system to overcome the disadvantages devices of the prior art by detecting the breakdowns of signaling indicators and in guaranteeing a good functioning even in the presence of some failures. The invention also relates to a method of managing such a device.

STATEMENT OF THE INVENTION

The present invention relates to a light information device concerning the state of operation of a system comprising at least one indicator light and means for detecting failure of this or these LEDs, characterized in that each LED includes m branches in parallel each consisting of n electroluminescent diodes in series, and means of selection of a branch, m and n being numbers integers such that: m ≥ 2 and n ≥ 1.

• un ensemble émetteur de lumière composé de m branches de n diodes électroluminescentes connectées en série et dans le même sens, les m premières extrémités de chaque branche étant connectées ensemble, leurs secondes extrémités étant connectées aux différentes entrées d'un sélecteur,
• ce sélecteur qui, en fonction d'un ordre de commande, relie une branche sélectionnée vers la sortie.

Advantageously each indicator comprises:

• a light emitting assembly composed of m branches of n light-emitting diodes connected in series and in the same direction, the first m ends of each branch being connected together, their second ends being connected to the different inputs of a selector,
• this selector which, according to a command order, connects a selected branch to the output.

• un générateur de courant qui alimente ce voyant,
• un module de commande qui pilote le sélecteur ainsi qu'un interrupteur,
• cet interrupteur qui est relié entre la sortie du sélecteur et l'entrée du générateur de courant.

This device advantageously comprises the following circuits associated with each indicator:

• a generator of current which feeds this indicator,
• a control module which controls the selector and a switch,
• this switch is connected between the output of the selector and the input of the current generator.

Advantageously, each indicator, its module control and its switch are integrated in a single housing.

The present invention also relates to a method of managing an information device light concerning the operating status of a system, comprising several LEDs each comprising several branches of several luminous elements, in which has a permanent automatic test step of all the lights of the system.

Advantageously, the process comprises a step of dynamic management of the redundancy in case of failure of a branch of a light.

• dans le cas où le voyant est allumé, on vérifie son bon fonctionnement en contrôlant l'intensité consommée et la tension présente à ses bornes,
• dans le cas où ce voyant est éteint, on le sollicite pendant une durée de l'ordre de quelques microsecondes et on mesure à cet instant ses paramètres courant/tension.

During the test step, we have the following steps for each LED:

• in the case where the indicator is lit, its functioning is verified by controlling the intensity consumed and the voltage present at its terminals,
• in the case where this indicator is off, it is solicited for a period of the order of a few microseconds and at this time its current / voltage parameters are measured.

During the dynamic management stage, we alternately illuminate the different branches of each LED with a polling frequency of the order of a few kilohertz, the parameters current / voltage being monitored at each scan. We no longer solicits a branch if a defect is found in this one. However, if all branches are in default, but if there is at least one branch remaining is not open circuit, we can requalify this (these) branch (s) as functional (s)

In the event that a defect is found in at least one branch, the duty cycle other flawless branches is changed to keep the same overall brightness at the LED.

The invention can advantageously be used in the avionics field.

Thus in the process of the invention, performs a permanent self-test of all lights of the cockpit of an airplane and we unload the pilot of this task. Such a continuous test allows to avoid, the non-detection of a hidden failure, by the pilot. In addition, the redundant structure of LEDs, allows immediate dynamic management in case of failure of this first redundancy without visible repercussion at the pilot level, and therefore without work overload for this one.

BRIEF DESCRIPTION OF THE DRAWINGS

Figures 1 and 2 illustrate two devices of the prior art.

Figures 3 and 4 illustrate the device of the invention.

Figure 5 illustrates an embodiment advantageous of the device of the invention.

DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS

• un ensemble 30 émetteur de lumière composé de m branches 31 de n diodes électroluminescentes (DEL) 32 (avec m ≥ 2 et n ≥ 1) les n diodes de chaque branche étant connectées en série et dans le même sens, les m premières extrémités de ces branches 31 étant connectées ensemble à l'entrée E, leurs secondes extrémités étant connectées aux différentes entrées d'un sélecteur 33,
• ce sélecteur 33, qui en fonction d'un ordre de commande C, relie une des branches 31 sélectionnée à la sortie S.

The light information device of the invention comprises at least one indicator 29 such as that shown in FIG. 3, which comprises:

• a light emitter assembly composed of m branches 31 of n light-emitting diodes (LEDs) 32 (with m ≥ 2 and n ≥ 1), the n diodes of each branch being connected in series and in the same direction, the first m ends of these branches 31 being connected together to the input E, their second ends being connected to the different inputs of a selector 33,
• this selector 33, which as a function of a control command C, connects one of the branches 31 selected at the output S.

A voltage measuring device 34 connected between the E input and the S output of the LED allows to know the voltage at the terminals of this indicator. An intensity measuring device 35 connected in output of the indicator 29 makes it possible to know the intensity of the current running through it.

As shown in Figure 4, the light 29 is powered by a current generator 40. A control module 41 driver on the one hand the selector 33 via a line 43 and secondly a switch 42 via a line 44. This control module 41 contains a memory for storing the functional state or not of each branch 31. The control signal of this module 41, conveyed on a command line 45, is a classic order given to a seer (On / off). A line of record 46 allows report the state of this seer 29 to external devices for alarm or maintenance for example.

• dans le cas où un voyant est allumé, il est facile de vérifier son bon état de fonctionnement en contrôlant régulièrement l'intensité consommée et la tension présente à ces bornes.
• dans le cas où un voyant est éteint, on utilise le même principe de mesure en sollicitant brièvement ce voyant. On alimente alors ce voyant durant une durée de l'ordre de quelques microsecondes, non perceptible par l'oeil humain, en respectant les valeurs de commande nominales. On mesure, à cet instant, les paramètres courant/tension de ce voyant.

The method of the invention realizes a dynamic test of all the indicators 29, for example those of an aircraft cockpit, such as:

• in the case where a light is on, it is easy to check that it is in good working order by regularly checking the current consumed and the voltage present at these terminals.
• in the case where a light is off, the same measurement principle is used by briefly soliciting this light. This indicator is then powered for a duration of the order of a few microseconds, not perceptible by the human eye, respecting the nominal control values. At this moment, the current / voltage parameters of this indicator are measured.

The method of the invention also provides a dynamic management of the redundancy of each which consists, using the selector 33, in alternately select the different branches 31 of this indicator with a polling frequency sufficiently high (of the order of a few kHz) for not to be perceived by the human eye.

At each scan, the parameters current / voltage of the indicator are checked. If a defect is found, the defendant branch is no longer requested and the other branches have their report cyclical ignition modified to keep the same overall brightness at the LED.

The method of the invention thus allows to avoid the total loss of the light. Also, even when the indicator light is not lit, the method of the invention continues his dynamic test by performing a brief control of the different branches. Upon the loss of first branch, it is possible to develop a message preventive maintenance without the pilot being informed.

So, if we consider the two states possible of a sight; light off or light on, we have the following operation:

- light off

No order arrives on the line of external control 45. The control module 41 opens and closes the switch 42 so as to power the seeing 29 by pulses sufficiently brief, by example of a duration of the order of a few microseconds, and spaced out so that the LED 29 seems extinct to an observer.

Each pulse is switched successively by the selector 33 on one of the branches 31. It measures the voltage across this branch and the current running through it.

• un courant nul : le circuit est ouvert et la branche ne peut plus fonctionner. Elle est considérée comme non fonctionnelle.
• une tension plus faible que la tension nominale : une diode au moins est en court-circuit. Le fait de considérer ou non la branche comme fonctionnelle dépend du rapport entre le nombre de diodes en bon état et le nombre de diodes de la branche, qui se trouve égal au rapport entre la tension mesurée et la tension nominale. Le fabricant ou l'utilisateur décide à partir de quelle baisse d'efficacité une branche doit être déclarée non fonctionnelle. Un tel mode de fonctionnement "voyant éteint" permet au module de commande 41 de connaítre avant tout ordre d'allumage, les branches fonctionnelles qui pourront être utilisées en mode "voyant allumé".

Two cases of failure can be detected (a light-emitting diode knows only two modes of failure, the short-circuit or the open circuit):

• a zero current: the circuit is open and the branch can no longer function. It is considered non-functional.
• a voltage lower than the nominal voltage: at least one diode is short-circuited. Considering whether or not the branch is functional depends on the ratio between the number of diodes in good condition and the number of diodes in the branch, which is equal to the ratio between the measured voltage and the nominal voltage. The manufacturer or user decides from which efficiency drop a branch must be declared non-functional. Such a mode of operation "indicator off" allows the control module 41 to know before any ignition command, functional branches that can be used in "light on" mode.

- light on

an ignition order has arrived on the line 45. The control module 41 closes the switch 42 so as to power the indicator 29 permanently. Cyclically, the selector 33 controlled by the signal C feeds the branches 31 functional one after the other.

• un courant nul : le circuit est ouvert et la branche ne peut plus fonctionner. Elle est considérée comme non fonctionnelle.
• une tension plus faible que la tension nominale : une diode au moins est en court-circuit. Le fait de considérer ou non la branche comme fonctionnelle dépend du rapport entre le nombre de diodes en bon état et le nombre de diodes de la branche qui se trouve égal au rapport entre la tension mesurée et la tension nominale.

For each branch 31 powered, two failure cases can be detected:

• a zero current: the circuit is open and the branch can no longer function. It is considered non-functional.
• a voltage lower than the nominal voltage: at least one diode is short-circuited. Whether the branch is considered as functional depends on the ratio between the number of good diodes and the number of diodes of the branch which is equal to the ratio between the measured voltage and the nominal voltage.

We can have a mode of operation gradient in which all branches are declared non-functional but in which it remains however at least one branch that is not in circuit open. In this case, the branch (s) in question can (wind) be requalified as functional, the LED emitting less light than when it was nominal operation.

Any failure detection can result in the emission of a signal on the line of report, intended for an operator and / or any maintenance.

In an advantageous embodiment, such as shown in FIG. 5, the indicator light 29, its module control 41 as well as the switch 42 are integrated in a single housing 50, with two lines 51, so as to present the appearance outside of an almost classic sight.

Claims (12)

Light information device relating to the operating state of a system, comprising at least one indicator light and means for detecting failure of this or these indicators, characterized in that each indicator comprises m branches (31) in parallel composed each of n light-emitting diodes (32) in series, and means (33) for selecting a branch, m and n being integers such that m ≥ 2 and n ≥ 1. An apparatus according to claim 1, wherein each indicator comprises: a light emitting assembly (30) composed of m branches (31) of n light-emitting diodes (32) connected in series and in the same direction, the first m ends of these branches being connected together, their second ends being connected to the different inputs a selector (33), this selector (33), which, as a function of a control command (C), makes it possible to connect a branch (31) selected at the output (S). Device according to claim 2, further comprising, for each indicator: a current generator (40) which supplies this indicator (29), a control module (41), which controls the selector (33) and a switch (42), and which contains a memory for storing the state of each branch (31), this switch (42) connected between the output of the selector (33) and the input of the current generator (40). Device according to claim 3, in which each indicator (29), its control module (41) and its switch (42) are integrated in a single housing (50). Use of the device according to one any of claims 1 to 4 in the field avionics. A method for managing a light information device relating to the operating state of a system, comprising a plurality of light indicators each comprising several branches of a plurality of light elements, characterized in that it comprises a step of automatically testing all the system lights. Process according to claim 6, which further includes a step of dynamic management of redundancy in case of failure of a branch of a seeing. The method of claim 6, wherein, during the testing step, the following steps are provided for each indicator: in the case where this indicator is lit, its operation is checked by checking the intensity consumed and the voltage present at its terminals, in the case where this indicator is off, it is solicited for a period of the order of a few microseconds and at this time its current / voltage parameters are measured. Process according to claim 7, in which, during the dynamic management stage, one alternately illuminates the different branches of each LED with a polling frequency of the order of a few kilohertz, the parameters current / voltage being monitored at each scan. Process according to claim 9, in which one no longer solicits a branch if a defect is found in this one. Process according to claim 9, in which if all the branches are in default, but if there is at least one branch that is not in circuit open, we requalify this (these) branch (es) as being Function (s). Process according to claim 9, in which in the case where a defect in at least one branch is found, the duty cycle flawless branches is changed to keep the same overall brightness at the LED.

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