Emergency lighting device with autonomous battery and with integrated night light function

Abstract

An emergency lighting device with autonomous battery, comprising a case (10), equipped with a light-transparent screen (11), which protects the inside of the case (10), wherein inside the case (10) there are a series of light sources, a lens (12) and a reflector (13) for shaping and diffusing the light beam coming from the light sources, a battery (18) and a printed circuit (14), which includes the electronic components (19) of an electronic circuit operating the device and which is connected to the input cables (15) of the power supply network (AC) and to the battery (18). The light sources are placed directly in front of and below the lens (12) and consist of a first group of white LEDs (20), which perform the illuminance functions and which are powered directly by the power supply network (AC) in the presence of network voltage or from the battery (18) in the event of a network failure or blackout, and by a second group of blue LEDs (21), which perform a night lighting function and which are powered by the power supply network (AC) in the presence of network voltage.

Description

[0001] The present invention relates to an emergency lighting device with autonomous battery and with integrated night-time courtesy light function.

[0002] The invention falls within the technical field of emergency and safety lighting and of functional lighting applied to devices having an autonomous battery.

[0003] In more detail, the aforementioned functions are combined in a new device which meets the regulatory requirements on safety lighting and the functional needs of night lighting (the so-called "courtesy lighting"), as well.

[0004] In particular, the invention makes it possible to obtain a convenient integration of a courtesy light for a soft night lighting in an emergency lighting device; this integration does not alter the general aesthetic appearance of the device and makes it possible to produce the device at a considerably reduced cost, in order to offer a useful additional function, but without a significant increase in the overall price of the product.

[0005] When the emergency lighting devices are in the "AO" (Always-On) mode, they provide the ordinary lighting function, allowing the room to be illuminated in the presence of the building's AC power supply network.

[0006] In most cases, the "AO" function is used to illuminate luminous signs for building evacuation, while, in other cases, the "AO" function is required for the actual lighting of rooms.

[0007] For these functions, the emergency lighting devices must be sized according to the application regulatory requirements that specify the illuminance of rooms, both in the case of ordinary conditions and in the event of a blackout.

[0008] The night-time courtesy lighting function is not regulated by regulatory requirements and, normally, it is intended to provide a minimum illuminance level which facilitates the orientation during short night-time movements inside the building and the identification of the controls for switching on the lights.

[0009] This type of courtesy light has a low light intensity.

[0010] The market offers night lights, but they are devices dedicated only to this function and, in general, they are not devices to be installed; moreover, they do not even integrate the most important emergency lighting functions according to the regulations in force in the event of a blackout.

[0011] The present invention therefore has the objective of providing an emergency lighting device with autonomous battery having the combined features of an emergency lighting function in the event of a blackout ("EO", Emergency Only), an ordinary lighting function in the presence of an AC power supply to illuminate the room or a luminous sign, i.e. a pictogram applied to the device's screen ("AO", Always On) and a blue light night-time courtesy lighting function.

[0012] Another objective of the emergency lighting device with autonomous battery according to the present invention is to integrate the blue light night-time courtesy lighting function, for creating the perception of a "nocturnal" atmosphere, at very low cost, in a lighting device built according to the state of the art of regulatory requirements on safety lighting.

[0013] A further objective of the present invention is to add the night-time courtesy lighting function to emergency lighting devices, using technical solutions that are highly synergistic with the manufacturing solutions currently adopted for such devices and with a very low cost increase. WO 01 / 95692 discloses an emergency lighting device with autonomous battery.

[0014] These and other aims are achieved by an emergency lighting device with autonomous battery according to the attached claim 1; further constructive details are given in the dependent claims.

[0015] The present invention will now be described, by way of non-limiting example, according to its preferred embodiments, and with the aid of the attached figures, wherein: Figure 1 is a schematic sectional representation of an emergency lighting device with autonomous battery, according to the present invention; Figures 2 and 3 show details of a possible embodiment of the lens and of a possible positioning of the lighting LEDs used in the emergency lighting device with autonomous battery, according to a preferred embodiment of the invention; Figure 4 illustrates the electronic circuit for operating the emergency lighting device with autonomous battery, according to the invention; Figure 5 is a schematic detail view of a possible application of control members to the electronic circuit of Figure 4, according to the present invention. With reference to the mentioned figures, the emergency lighting device, which is the object of the present invention, comprises an outer case 10 equipped, on one of its sides, with a light-transparent screen 11 protecting the inside of the case 10 against water and dust entry.

[0016] Inside the case 10 there are a lens 12 for shaping and diffusing the light beam, a reflector 13 which, in combination with the lens 12, shapes the light emitted by the light sources of the device, and a single printed circuit 14 (PCB Printed Circuit Board) which is connected, via a terminal board 16 mounted on the printed circuit 14, to the input cables 15 of the AC power supply network and, via a dedicated cable 17, to a battery 18, for example a lithium battery, housed and fixed inside the case 10 (Fig. 1).

[0017] The printed circuit 14 includes all the electronic components 19 of the electronic circuit operating the device, and the light sources, which consist of two groups of LEDs: a first group of white LEDs 20, which perform the illuminance functions according to the regulatory requirements on safety lighting and which are powered directly by the energy of the AC power supply network in the presence of a network (AO function), in the event that such AO function is activated, or by the energy supplied by the battery 18 in the event of a blackout (EO function); a second group of blue LEDs 21, which perform the night-time courtesy lighting function, powered only by the energy of the AC power supply network in the presence of a network ("night function"), in the event that this "night function" is enabled.

[0018] The two groups of LEDs 20, 21 are positioned under the same lens 12, so that the user perceives the product as a single light source which lights up differently according to the function which is active: blue in case of a night-time courtesy light, at low intensity or white in case of EO or AO, at intensities corresponding to the regulatory requirements.

[0019] The printed circuit 14 is positioned so that the LEDs 20, 21 are directly facing the lens 12 and it is made with technical solutions which minimize the cost of the described functions by means of strong synergies among the various blocks constituting it.

[0020] Figures 2 and 3 show an enlarged constructive detail of a possible embodiment of the lens 12 and of the positioning of the LEDs 20, 21.

[0021] The type of lens 12, shown in Figure 2 and shaped like a "gull wing", widens the beam of light emitted from the LEDs 20, 21 making it possible to gain a greater extension of the illuminated area, for example for positioning the device in long corridors (if the lens 12 is positioned orthogonally to the length of the corridor itself); in this way, even the night-time courtesy light diffuses more widely along the corridor providing a condition of diffused light which, despite the low intensity, allows people to better orient themselves inside the building.

[0022] Figure 4 shows a block diagram of the electronic operating circuit, formed in the printed circuit 14 of the emergency lighting device, according to the present invention.

[0023] At the input there is an AC / DC converter 25, which powers the lighting device from the AC power supply network; the AC / DC converter consists of a capacitive type current limiter (CI) 26 connected upstream a rectifier 25, which supplies, downstream the rectifier itself, a direct current used by the following blocks, all connected in series to each other: battery 18 (charge current), via the connector 22; blue LEDs 21 for the night light; white LEDs 20 for the AO function; one or more LEDs 23 indicating the status of the device.

[0024] Each block is activated by suitable shunt devices driven according to the settings of the device itself and / or the presence or absence of the AC power supply network.

[0025] A BOOST type switching converter 27, which raises the voltage of the battery 18 (preferably consisting of a single lithium cell) to the value necessary to drive the group of white LEDs 20, is used for the EO function.

[0026] The white LEDs 20, by means of simple diode switches, in the event of a blackout, no longer receive current from the AC side, but from the BOOST converter 27 powered by the battery 18; in this way it is advantageously obtained an electronic circuit at very low cost and with high reliability, which performs the described functions.

[0027] In particular, the input AC power supply network powers the capacitor CI, which, thanks to its reactance at the network frequency, limits the current absorbed by the downstream circuits to the desired value.

[0028] The intensity of the current depends on the difference between the input voltage VAC and the voltage across the circuit, downstream the rectifier, comprising the following components in series: battery 18, bicolour signaling LEDs 23, white LEDs 20, blue LEDs 21.

[0029] As mentioned, the battery 18 used is preferably of the single lithium cell type 28 (nominal voltages from 2.4 V for the LTO batteries to 3.2 V for the LiFePO4 batteries to 3.7 V for the lithium-ion batteries). The bicolour signaling LED 23 has a maximum voltage across it of 2-3 V, the white LEDs 20 offer a voltage drop, if on, of 10-12 V, while the blue LEDs 21 add about 3 V, if on.

[0030] So, overall, the series can reach a total of around 20-22 V, if all the LEDs are on, while if the LEDs are all off (short-circuited) the voltage can assume a value of around 6-7 V.

[0031] In respect of the AC network voltage, typically of 200-240 VAC, this voltage variation from 22 V to 6 V is reflected in modest tolerable variations in the current limited by the capacitor CI.

[0032] In fact, if it is examined the variation of the limited current intensity in the two extreme conditions indicated, i.e. with a network voltage VAC of 230 V, the variation is on the order of approximately 5%.

[0033] It should also be noted that usually only one of the two groups of LEDs 20, 21 is on at a time (either just the white LEDs 20 or just the blue LEDs 21) and therefore the possible variations in the current are even smaller between the two actual operating conditions.

[0034] The electronic circuit of Figure 4 thus implements a limited current power supply in a range of values widely acceptable for being applied.

[0035] The circuit schematized in Figure 4 also includes: a network sensor 24 determining, on the basis of a threshold value, whether the input voltage VAC is lower or higher than this threshold value to determine if there is a blackout; the BOOST type switching converter 27, adapted to drive the string of white LEDs 20 which are characterized by a voltage higher than that of the single cell 28 of the battery 18, in blackout conditions (absence of the AC power supply network); the battery 18 containing one or more lithium cells 28 and integrating a PCM (Protection Circuit Module) constructed so as to protect the battery 18 from overvoltages, undervoltages and overcurrents; a circuit Q1 for driving the signaling LEDs 23, so as to turn on a red light if the battery 18 is not connected; a voltage limiter LIM, which makes the current set by CI flow when the cell 28 disconnects, as the cell 28 has reached the maximum permissible voltage during the charge phase.

[0036] The operation of the electronic circuit schematized in Figure 4 is substantially as follows.

[0037] In the presence of a 230VAC power supply, the current regulated by CI charges the cell 28 present in the battery pack 18 if the voltage across the cell 28 is lower than the maximum voltage settled for that type of cell. The cell 28 recharges until the voltage across the cell 28 exceeds the maximum value during the charge phase and, as soon as this value is reached, the PCM turns off Q3 and the charge stops; the input current now flows in the limiter LIM, which can be a Zener diode or a "parallel" feedback voltage regulator.

[0038] When the battery voltage 18 drops below the minimum charge voltage, Q3 turns on again and the charge process restarts.

[0039] In the presence of the power supply network, the current regulated by CI can pass through the blue LEDs 21 (all connected in parallel to each other) if the jumper P1 is open (in which case the LEDs 21 will be on and, vice versa, if the jumper P1 is connected, the blue LEDs 21 will be off).

[0040] By using the jumper P1 it is therefore possible to configure the device during its installation to determine whether the night light function is active or not.

[0041] The jumper P1 can be replaced by a switch that can be remotely managed to control the night function even once the device has been installed.

[0042] The same current regulated by CI, in the presence of the AC power supply network at the input, can pass through the white LEDs 20 if the jumper P2 is open (in which case the white LEDs 20 will be on and, vice versa, if the jumper P2 is connected, the white LEDs 20 will be off).

[0043] By using the jumper P2 it is therefore possible to configure the device during its installation to determine whether the AO function is active or not.

[0044] The jumper P2 can be replaced by a switch that can be remotely managed to control the AO function even once the device has been installed.

[0045] The jumpers P1 and P2 can also be connected in parallel to a remotely controllable two-position switch (DEV1) to drive the two possible operating options by one control, as shown in Figure 5.

[0046] In this case, the AO function is active in position 1 and the night function is active in position 2.

[0047] The combination with jumpers P1 and P2 can also make it possible to enable only one of the two (AO and night) functions during installation.

[0048] Again with reference to the electronic circuit of Figure 4, in absence of the AC power supply network, the sensor 24, identifying this condition, deactivates the output signal which turns on the BOOST converter 27 and the transistor Q2, with the result of imposing the passage of current in the white LEDs 20, turning them on, with the desired intensity, regulated by the BOOST converter 27; in this way the emergency function EO is obtained.

[0049] As evident from the circuit diagram of Figure 4, the diodes D1, D2 and D3 automatically switch the white LEDs 20 from the circuit relating to the AO operation (in the presence of the power supply network) to the EO circuit of the BOOST converter 27 (in the absence of the power supply network).

[0050] Finally, the bicolour (typically red and green) LED 23 signaling the status of the device is driven by the transistor Q1, which is activated if the connector 22 of the (three pole) battery 18 is correctly inserted in the circuit. In this condition, since Q1 is on, the red led is shunted and only the green signaling led remains on; vice versa, if the battery 18 is not connected, the red LED turns on signaling the anomaly and the green LED remains off.

[0051] From the description provided herein, therefore, the characteristics of the emergency lighting device with autonomous battery, object of the present invention, are clear, as well as the advantages thereof are clear.

[0052] Finally, it is clear that numerous other variants can be made to the emergency lighting device in question, without thereby departing from the principles of novelty inherent in the inventive idea expressed in the attached claims, just as it is clear that, in the practical implementation of the invention, the materials, shapes and size of the illustrated details may be any depending on the requirements and they may be replaced with other equivalent ones.

[0053] Where the constructive characteristics and the techniques mentioned in the attached claims are followed by reference signs or numbers, these reference signs have been introduced with the sole aim of increasing the intelligibility of the claims themselves and, consequently, they do not have any limiting effect on the interpretation of each element identified, purely by way of example, by these reference signs.

Claims

1. An emergency lighting device with autonomous battery, comprising a case (10), equipped with a light-transparent screen (11), which protects the inside of the case (10), wherein said case (10) contains a plurality of light sources, a lens (12) and a reflector (13) for shaping and diffusing the light beam coming from said light sources, a battery (18) and a printed circuit (14), which includes the electronic components (19) of an electronic circuit operating the device and which is connected to the input cables (15) of the power supply network (AC) and to said battery (18), wherein said light sources are placed directly in front of and below said lens (12) and consist of two groups of LEDs: - a first group of white LEDs (20), which perform the illuminance functions and are powered directly by said power supply network (AC) in the presence of network voltage, or by said battery (18) in the event of a network voltage failure or blackout; - a second group of blue LEDs (21), which perform a night lighting function and which are powered by said power supply network (AC) in the presence of network voltage.

2. The emergency lighting device as claimed in claim 1, characterized in that said lens (12) is shaped like a gull wing, so as to widen the light beam coming from said light sources.

3. The emergency lighting device as claimed in at least one of the preceding claims, characterized in that said electronic circuit operating the device includes an AC / DC converter (25) which powers the lighting device from said power supply network (AC), said AC / DC converter (25) being constituted by a capacitive type current limiter and by a rectifier (26), so as to supply a direct current to said first and second group of white and blue LEDs (20, 21), to said battery (18) and to one or more LEDs (23) for signaling the status of the device.

4. The emergency lighting device as claimed in at least one of the preceding claims, characterized in that said electronic circuit includes a BOOST type switching converter (27), which raises the voltage of the battery (18) to a value adapted to drive said first group of white LEDs (20).

5. The emergency lighting device as claimed in at least one of the preceding claims, characterized in that said battery (18) is of the single lithium cell type (28).

6. The emergency lighting device as claimed in claim 5, characterized in that said electronic circuit also includes a network sensor (24) which determines if there is a blackout in the power supply network (AC), and characterized in that said battery (18), which contains said single cell (28), integrates a protection module (PCM) adapted to protect said cell (28) from overvoltages, undervoltages and overcurrents.

7. The emergency lighting device as claimed in claim 6, characterized in that said electronic circuit includes a circuit (Q1) for driving said one or more LEDs (23) signaling the connection of said battery (18) and a voltage limiter (LIM) which operates when said battery (18) disconnects said inner cell (28).

8. The emergency lighting device as claimed in at least one of the preceding claims, characterized in that at least one switch element (P1, P2) is configured to activate or deactivate said first and / or second group of white and blue LEDs (20, 21).

9. The emergency lighting device as claimed in claim 8, characterized in that said at least one switch element (P1, P2) is connected in parallel to a remotely controllable two-position switch (DEV1).

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