[0001] The present invention relates to a lighted
status indicator for electric, electronic and similar equipment.
[0002] A lighted
status indicator has the function of making a user aware of the state of electric or electronic equipment:
for example, a green light may indicate a correct operation, a red light a failure,
etc.. Lighted indicators of the type in reference are present on household appliances,
such as refrigerators and vacuum cleaners, on light switches, on personal computers.
[0003] It is known that in lighted
status indicator a first type of light source may consist of microlamps of a 3-6 mm diameter which
contain a gas and in which an electric discharge takes place.
[0004] These microlamps are connected in an alternating-current circuit the supply voltage
of which, included between standard values of 110V and 380V at 50 Hz, is reduced to
the necessary flashover voltage of said microlamps, usually of about 90V, by an appropriate
resistor having a resistance of a value approximately included between 48 and 270Kohm.
[0005] Practically, said microlamps are able to supply a light intensity of about 8-13 millicandles
(mcd) and have an average lifetime of about 15 thousand hours.
[0006] The above mentioned prior art has some drawbacks.
[0007] In fact, first of all, it allows light sources to be made available that are characterized
by a limited range of colours, i.e. generally only red, green, more seldom blue, since
other colours would involve use of expensive gases capable of greatly increasing the
microlamp costs to such an extend that they would be no longer competitive.
[0008] In particular, it is to be pointed out that it is not possible to obtain a white
light but only a light of a colour tending to yellow.
[0009] In addition, the average lifetime of said microlamps can be inappropriate for some
applications, also because brightness of same has a tendency to be reduced with use,
due to formation of deposits on the inner surface of the small transparent bulbs forming
the lamp bodies, and to lose steadiness due to arising of flickering phenomena.
[0010] In order to overcome at least some of the drawbacks of the microlamps briefly described
above, utilisation of a second type of light source is also known which is based on
use of LEDs, i.e. light-emitting diodes, of the type capable of supplying a light
intensity of about 10mcd.
[0011] These LEDs not only offer availability of a wide range of colours among which white,
but also have an average lifetime of about 50 thousand hours, i.e. a lifetime that
is more than three times higher than the lifetime of gas-discharge microlamps, while
maintaining a steady light with a constant intensity.
[0012] One of such light-emitting diodes is known from document US6543904B1 which discloses
an illuminating element for vehicles provided with an intermediate element containing
the activation electronics for activating the LED. The illuminating element is mounted
on a printed circuit board by means of a contact socket.
[0013] However said LEDs too have some drawbacks.
[0014] First of all, there is a need for a rather complicated feeding circuit to enable
them to be connected with an electric network having the standardized line voltages,
varying between 110 and 230V at 50Hz.
[0015] In the above mentioned feeding circuit in fact, in addition to a first diode disposed
in series with the LED itself, the presence of a capacitor and a first resistor disposed
in parallel, and of a second resistor and a second diode suitably interposed between
the other components is provided.
[0016] The capacitor and first resistor perform the function of reducing voltage and current
to the values required by the LED, 2V and 20mA (milliampere) for example, whereas
the second resistor and second diode discharge possible voltage peaks present in the
network.
[0017] Practically, the necessary presence of said feeding circuit made up of many components
increases the cost of the LED alone to be used as the light source, to a rather important
extent.
[0018] It will be also recognised that the sizes of the feeding circuit associated with
the LED make it impossible to use the same in
status indicators the maximum diameter of which must not overcome 7 mm.
[0019] Finally, it is also to be pointed out that, specifically, the feeding circuit of
the gas-discharge lamp, due to the presence of the resistor, produces heat to an important
amount and therefore gives rise to useless high temperatures, in addition to energy
losses.
[0020] It is also known, from document US2002/0140379A1, a LED lighting device comprising several extra LEDs such that, as the LEDs of the lighting
device degrade over time, more LEDs can be turned on thus allowing a constant luminosity
to be maintained. Such LEDs are of the super bright type and are used at full current
for a fractional time.
[0021] Under this situation, the technical task underlying the present invention is to devise
a lighted
status indicator for electric, electronic and similar equipment that is capable of substantially obviating
the mentioned drawbacks.
[0022] Within the scope of this technical task, it is an important aim of the invention
to devise a lighted
status indicator that, in addition to enabling a constantly steady light emission devoid of flickering
phenomena, which can be of any colour and therefore also white, is of very high useful
lifetime too, much higher than that obtainable with standard LEDs, but at much more
reduced production costs as compared with those of said LEDs.
[0023] The technical task mentioned and the aims specified are substantially achieved by
a lighted
status indicators according to one or more of the appended claims.
[0024] Description of two preferred but not exclusive embodiments of a lighted
status indicators in accordance with the invention is now given hereinafter with the aid of the accompanying
drawings, in which:
- Fig. 1 diagrammatically shows a first embodiment of a lighted status indicator in accordance with the invention;
- Fig. 2 is a perspective view of a second embodiment of the lighted status indicator; and
- Fig. 3 shows the wiring diagram of the feeding circuit of the status indicator seen in Figs. 1 and 2.
[0025] With reference to the drawings, the lighted
status indicator in accordance with the invention is generally identified with reference numeral 1.
[0026] It comprises at least one LED 2 of the
super bright type, also called "high-efficiency LED", that, as known, is able to ensure an average
duration of about three hundred thousand hours.
[0027] LED 2 can be selected from the LEDs of the above mentioned type with a diameter of
3 to 5 mm and characterised by a maximum light emission included between 50 and 16000
mcd when said LEDs are passed through by a standard current intensity of about 20mA.
[0028] In an original manner, LED 2 is submitted to passage of a current therethrough which
has an operating intensity equal to a fraction of said standard intensity obtained
by a simple feeding circuit 3. Corresponding to this operating current intensity is
a light intensity that is reduced to few units or some tens of millicandles adapted
for use in the indicators being the object of the invention.
[0029] The feeding circuit comprises a resistor 4 and a diode 5 set in series with respect
to LED 2 and consisting of components
provided with rheophores (see Fig. 2) or disposed internally of an integrated circuit (see Fig. 1) and consisting
of components suitable for surface mounting.
[0030] For example, should the feeding circuit 3 be connected with an alternating-current
network with a voltage included between 110 and 230V at 50 Hz, resistor 4 may have
a resistance included between 50 and 200Kohm, preferably of about 120kohm.
[0031] LED 2, preferably selected from LEDs with a 3 mm diameter and capable of approximately
supplying a 340mcd current with 20mA, is in this case passed through by an operating
current intensity of few milliamperes. For instance, the current intensity is included
between 0.2 and 5mA. Preferably, the current intensity is of about 1mA to which, just
as an indication, a light emission of 17mcd corresponds, which value is adequate for
a standard
status indicator.
[0032] The invention achieves important advantages.
[0033] In fact, first of all, the
status indicator in accordance with the invention has a very high operating lifetime, without any
reduction in light emission, not only higher than that of indicators with gas-discharge
microlamps, but also higher than when light sources formed of LEDs of standard type
are used, which LEDs in any case cannot be used for said
status indicators due to their sizes.
[0034] In addition, it is to be pointed out that the
status indicator in accordance with the invention comprises a very simple feeding circuit, only formed
of one diode and one resistor. This structural simplicity is made possible by the
fact that operation of said LED takes place with a much lower current intensity than
that considered as the standard operating current and therefore under operating conditions
that do not require additional components to protect the LED from possible voltage
and current peaks present in the network, and this practically results in very reduced
and competitive production costs as compared with other types of
status indicators.
[0035] Furthermore, these
status indicators have a tendency to heat up to a very reduced extent.
[0036] Finally, it will be appreciated that the
status indicators in accordance with the invention can be such produced that they give rise to light
emissions of any colour.
1. A lighted status indicator for electric, electronic and similar equipment, comprising
at least one LED (2) and a feeding circuit (3), characterised in that said at least one LED (2) is of the super bright type selected from the LEDs having
a light emission included between 50 and 16000mcd with a standard current intensity
of about 20mA and the feeding circuit (3) is adapted to submit said LED (2) to passage
therethrough of a current having an operating intensity included between 0.2 and 5mA.
2. A lighted status indicator as claimed in claim 1, characterised in that said feeding circuit (3) comprises a resistor (4) and a diode (5) disposed in series
with respect to said LED (2).
3. A lighted status indicator as claimed in claim 2, characterised in that said resistor (4) and diode (5) consist of components provided with rheophores.
4. A lighted status indicator as claimed in claim 2, characterised in that said resistor (4) and diode (5) consist of components suitable for surface mounting.
5. A lighted status indicator as claimed in claim 2, characterised in that said resistor (4) and diode (5) are inserted internally of an integrated circuit.
6. A lighted status indicator as claimed in claim 1, characterised in that the operating current intensity to which said LED is submitted is of 1mA.
7. A lighted status indicator as claimed in claim 2, characterised in that said resistor (4) has a resistance included between 50 and 200Kohm and preferably
of 120Kohm.
8. Use of a LED (2) and a feeding circuit (3) according to claims 1 to 7 as a lighted
status indicator for household appliances, light switches or personal computers.
1. Zustandsleuchtanzeiger für elektrische, elektronische und ähnliche Geräte, umfassend
mindestens eine LED (2) und eine Speiseschaltung (3), dadurch
gekennzeichnet, dass die mindestens eine LED (2) nach der Art mit hoher Lichtausstrahlung ist, gewählt
unter den LED, die eine Lichtausstrahlung zwischen 50 und 16000 mcd mit einer Standardstromstärke
von etwa 20 mA aufweisen und die Speiseschaltung (3) fähig ist, die LED (2) einem
Stromdurchfluss auszusetzen, der eine Stromstärke zwischen 0,2 und 5 mA aufweist.
2. Zustandsleuchtanzeiger nach Anspruch 1, dadurch gekennzeichnet, dass die Speiseschaltung (3) einen Widerstand (4) und eine Diode (5) umfasst, die gegenüber
der LED (2) in Reihe geschaltet sind.
3. Zustandsleuchtanzeiger nach Anspruch 2, dadurch gekennzeichnet, dass der Widerstand (4) und die Diode (5) aus Bestandteilen mit Leitungen besteht.
4. Zustandsleuchtanzeiger nach Anspruch 2, dadurch gekennzeichnet, dass der Widerstand (4) und die Diode (5) aus Bestandteilen bestehen, die für die Montage
an der Oberfläche geeignet sind.
5. Zustandsleuchtanzeiger nach Anspruch 2, dadurch gekennzeichnet, dass der Widerstand (4) und die Diode (5) innerhalb einer Leiterplatte eingebaut sind.
6. Zustandsleuchtanzeiger nach Anspruch 1, dadurch gekennzeichnet, dass die Stromstärke, der die LED selbst ausgesetzt ist, gleich 1 mA ist.
7. Zustandsleuchtanzeiger nach Anspruch 2, dadurch gekennzeichnet, dass der Widerstand (4) einen Widerstandswert zwischen 50 und 200 Kohm, bevorzugter Weise
gleich 120 Kohm aufweist.
8. Verwendung eines LED (2) und einer Speiseschaltung (3) nach Anspruch 1 bis 7, als
Zustandsleuchtanzeiger für Haushaltsgeräte, Lichtschalter, Personalcomputer.
1. Indicateur lumineux d'état de fonctionnement pour appareil électrique, électronique
et similaire, comprenant au moins une diode électroluminescente (LED) (2) et un circuit
d'alimentation (3), caractérisé en ce qu'au moins une LED (2) est du type à émission lumineuse supérieure choisi parmi les
diodes électroluminescentes ayant une émission lumineuse comprise entre 50 et 1600
mcd avec une intensité de courant standard d'environ 20 mA et le circuit d'alimentation
(3) est apte à soumettre ladite diode électroluminescente (2) au passage d'un courant
ayant une intensité de fonctionnement comprise entre 0,2 et 5 mA.
2. Indicateur lumineux d'état de fonctionnement selon la revendication 1, caractérisé en ce que le circuit d'alimentation (3) comporte une résistance (4) et une diode (5) disposées
en série par rapport à ladite diode électroluminescente.
3. Indicateur lumineux d'état de fonctionnement selon la revendication 2, caractérisé en ce que lesdites résistance (4) et diode (5) consistent en éléments composants munis des
connexions d'électrodes.
4. Indicateur lumineux d'état de fonctionnement selon la revendication 2, caractérisé en ce que lesdites résistance (4) et diode (5) consistent en éléments composants aptes au montage
de surface.
5. Indicateur lumineux d'état de fonctionnement selon la revendication 2, caractérisé en ce que lesdites résistance (4) et diode (5) sont insérées à l'intérieur d'un circuit intégré.
6. Indicateur lumineux d'état de fonctionnement selon la revendication 1, caractérisé en ce que l'intensité de fonctionnement du courant auquel ladite diode électroluminescente
est soumise est de 1 mA.
7. Indicateur lumineux d'état de fonctionnement selon la revendication 2, caractérisé en ce que ladite résistance (4) a une résistance comprise entre 50 et 2000 Kohm et de préférence
de 120 Kohm.
8. Usage d'une diode électroluminescente (2) et d'un circuit d'alimentation (3) selon
les revendications 1 à 7, comme indicateur lumineux d'état de fonctionnement pour
appareils ménagers, interrupteurs d'éclairage ou ordinateurs personnels.