FI97935C - Lighting systems - Google Patents

Description

97935

The luminaire arrangement

The invention relates to a lighting arrangement for developing two different light output levels, for example in a vehicle, which arrangement comprises incandescent lamps for developing a higher light output level and light emitting diodes for developing a lower light output level.

Typically, in vehicles such as coaches, normal interior lighting and night lighting 10, respectively, are treated with incandescent lamps. The interior lighting is treated with bright incandescent lamps and the night lighting with blue or green colored lamps. The problem is the relatively short lifespan of the lamps (1000 ... 3000 h), which still drops when the voltage rises from its nominal value, for example 24 V, often to 26 ... 27 V during driving (charging). This short lamp life results in the need to change lamps relatively often, which results in both supplies and labor costs.

It is an object of the present invention to provide a luminaire arrangement in which the lifespan of the lamps is made substantially longer and in which it is simple to provide two different levels of light, i.e. for day and night use. This is achieved by means of the luminaire arrangement according to the invention, which is characterized in that it comprises at least one incandescent lamp and at least one; . ·. elements and means comprising a series of light emitting diodes for connecting a higher or lower voltage level to said elements to develop a higher and lower light power level, respectively.

V * According to a preferred embodiment of the invention, the means for switching either a higher or lower voltage level over said elements comprise a regulator for keeping the supply voltage level acting above said elements at a value corresponding to either a higher or lower light level 2 97935. According to another embodiment, the means for switching either a higher or lower voltage level over said elements comprises switching means for switching said elements either above the parallel supply voltage to generate a higher light output level or as sets of two or more elements to develop above the parallel supply voltage.

In the luminaire arrangement according to the invention, the incandescent lamp 10 acts on the one hand as a series resistor required by the light emitting diode and on the other hand the diode takes part of the supply voltage, so that the incandescent lamp does not reach its full voltage if the supply voltage is rated to match the incandescent lamp voltage.

By using the regulator to set the supply voltage, on the other hand, the desired voltage levels in both operating modes can be accessed and the transition from one level to another can be carried out steplessly if desired.

In a preferred embodiment, the regulator is adapted to regulate a supply voltage level corresponding to a higher light output level to a substantially rated voltage of the incandescent lamp, such as 24 V, and a lower light output level; supply voltage level to less than 50% of said nominal voltage, such as to about 10 V. By adjusting the 4 · · • ·, ·. the voltage level corresponding to the higher light output level to the nominal voltage of the light bulb • f i, a favorable situation is reached in which the light bulb never reaches its full voltage, as a result of which its lifespan is significantly increased. · Ϊ · * 3 0 In night lighting, the series connection of an incandescent lamp and a diode v: on the other hand, for example, a voltage of about 10 V, so that the diode still lights up at about 80% light output due to its threshold voltage, while the incandescent lamp is almost dark.

In the following, the luminaire arrangement li 3 97935 according to the invention will be described in more detail with reference to the accompanying drawing, Fig. 1 shows a schematic circuit diagram for a luminaire-5 arrangement according to a first embodiment of the invention, Fig. 2 shows a schematic circuit diagram for a luminaire arrangement according to a second embodiment of the invention power level and Fig. 3 shows the embodiment of Fig. 2 when adapted to generate a lower light power level.

The exemplary circuit diagram of the luminaire arrangement according to the invention shown in Fig. 1 has a plurality of series connections of an incandescent lamp 1 and a light emitting diode 2, designated elements 4. In the illustrated embodiment, element 4 comprises one incandescent lamp and one light emitting diode. or why not more incandescent bulbs and likewise the number of diodes may vary. For example, a switch with two incandescent bulbs may also be economically advantageous because the price of 12 V incandescent bulbs is substantially lower than the price of 24 V incandescent bulbs.

. According to the invention, the elements 4 are connected in parallel with respect to the supply voltage supplying these elements.

• ·::: This supply voltage can be set to the desired value using regulator 3. If the rated voltage of incandescent lamps is 24 V, as is typically the case on buses, it can be regulated. . ·. by means of the torch 3 the supply voltage for daylight is set to 'Y' '30 Telia to that voltage value of 24 V. In this case, the voltage level acting above the light bulb • · · lamp 1 and the light emitting diode 2 is 24 V. Since the light emitting diode draws from the voltage due to its threshold voltage of about 3 V and burns at full light output, only about 21 V remains above the bulb 1 35. With a nominal lamp voltage of 4,97935 at 24 V, this 3 V voltage drop means that the incandescent lamp is supplied with a voltage slightly below 90% of the nominal voltage, increasing its service life by about three times its nominal value.

In the case of normal indoor lighting, a voltage is supplied to the regulator 3 from the battery / charger of a means of transport, such as a bus, whereby the corresponding voltage levels can be, for example, 24 V and 27 V. However, the regulator 3 can stabilize this voltage at said 10 24 V. When night lighting is required, a control voltage is applied to the regulator 3, which is applied to the terminal marked +24 V Night light in the wiring diagram shown in the figure. From this voltage, a control voltage is generated for the regulator-15 by means of a voltage divider formed by three resistors R1, R2 and R3, which drops the supply voltage of the luminaires to less than 50% of the rated voltage of the incandescent lamps, such as 10 V. In this case, about 15 V if the regulator is 20 such that the voltage difference between its control terminal and the output terminal is regulated, for example, to a value of about 5 V.

When a supply voltage of 3 10 V is applied to the luminaire arrangement in night light operation from the regulator, this voltage. · The volume is divided into 25 parts of the filament lamp 1 and the light emitting diode 2 ·. '··. Even at such a voltage, the light emitting diode • · • ^ · 2 still operates at a light output of about 80% due to its threshold voltage. However, the voltage level received by the incandescent lamp is so low that it glows very dimly or is almost. dark. In this way, by using a lower supply voltage, the lights can be switched to the light power level corresponding to the night lighting at which the light emitting diodes operate. ’In practice as exclusive light sources.

It should be noted that in the connection according to the invention, the incandescent lamp, which is in series with the light emitting diode 35, at the same time also acts as the series resistor provided by the light emitting diode 5 97935 and no separate series resistor is required.

A further advantage of the lighting arrangement according to Fig. 1 can be mentioned that by using the regulator 3, the switching current pulse of the lamps 5 is eliminated. Typically, the beam current of the bus is about 20 A while the switching current pulse is about ten times, i.e. at 200 A. A further advantage of the lighting arrangement according to the invention is that it can be very simply dimmed with conventional dimmers.

Another exemplary embodiment of the invention is shown in Figures 2 and 3. It, like the embodiment of Figure 1, uses elements 4 formed by an incandescent lamp 1 and a light emitting diode 2. In the situation of Figure 2, these elements 4 are connected directly across the positive and negative terminals of the supply voltage. over the element will be affected by the supply voltage between these terminals. In buses, this voltage is typically 24 V, which often drives to 26 ... 27 V during driving and when the charger is 20 in operation. When the nominal voltage of the incandescent lamp 1 is 24 V, the incandescent lamp still does not receive a voltage that exceeds this nominal voltage because the light emitting diode 2 takes part in the supply voltage:. approx. 3 V. In this connection, too, the life of the light bulbs is extended compared to a situation in which the voltage generated by the vehicle battery / charger is supplied directly over the light bulb. In the situation according to Figure 2, both the incandescent lamp and the light emitting diode are fully operational with respect to the diode. . ·. with its luminous intensity and, in the case of an incandescent lamp, with either a full luminous intensity of • · · 30 or a slightly lower luminous intensity, • · · if the supply voltage falls below 27 V.

M »

Figure 2 further shows a switch arrangement 5 by means of which the connection of the elements 4 can be changed. In the case according to Fig. 2, the full supply voltage acts over both elements 4 35. However, in the situation 6 97935 according to Fig. 3, the switch 5 has changed its switching position, whereby the second terminals of the elements 4 are connected directly to each other without being connected to either pole of the supply voltage. In this case, the two elements 4 are connected in series over the supply voltage. In this case, part of both elements receive about half of the supply voltage, i.e. about 12 V in the case of a 24 V supply voltage. In this situation, the light emitting diode still operates at about 80% light output due to its threshold voltage, while the voltage above 10 incandescent lamps is so low. that the light bulb is practically dark.

In the embodiment according to Figures 2 and 3, by means of a very simple switching means provided by the switching means 5, the voltage acting across the elements 4 can be dropped from full value to half value.

This represents a substantial change in the light power level corresponding to the change achieved in connection with the embodiment of Figure 1. These two different light output levels are well suited for the implementation of bus interior lighting and night lighting to-20, respectively.

The luminaire arrangement according to the invention has been described above with the aid of only one exemplary embodiment, and it is to be understood that some modifications may be made to it without departing from the scope defined by the appended claims. Thus, the arrangement by which • · · the filament lamp or lamps and the light-emitting diode

«M

: The voltage across the d or element formed by the diodes is changed to require a higher light output level. from the value to the value required for the lower light output level, there may be a regulator other than the one described or a voltage-reducing * t »• switching change. Other types of means and arrangements for providing two different levels of supply voltage are of course also possible in connection with the luminaire arrangement according to the invention. It should also be noted that the combination of one incandescent lamp and one diode is only an example of the structure of the element used, and two or more incandescent lamps could naturally be placed in the element, taking into account the correct dimensioning, and correspondingly the number of diodes may be greater than 5.

• · • · · »· ·

• · · I

♦ · «• · · ♦ ♦ ♦ ♦« · · • · r · »» • · «» · · ♦ ·· • ♦

Claims (5)

97935 A lighting arrangement for generating two different light output levels, for example in a vehicle, the arrangement comprising incandescent lamps (1) for generating a higher light output level and light emitting diodes (2) for generating a lower light output level, characterized in that it comprises at least one incandescent lamp (1) and at least elements (4) and means (5; 3) comprising a series connection 10 of one light emitting diode (2) for switching either a higher or lower voltage level over said elements (4) to generate a higher and lower light power level, respectively. Luminaire arrangement according to claim 1, characterized in that the means for switching either a higher or lower voltage level over said elements (4) comprise a regulator (3) for maintaining a supply voltage level acting over said elements (4) corresponding to either a higher or lower light output level. value. Luminaire arrangement according to claim 1 or 2, characterized in that said element (4) is as such connected directly over the supply voltage. *. ‘I 25 A luminaire arrangement according to claim 2. ly, characterized in that the regulator (3) is adapted to regulate a supply voltage level corresponding to a higher light output level substantially to the rated voltage of the filament lamp, such as 24 V, and a supply voltage level corresponding to a lower light output level below 50 ° C. to said% II 97935 elements (4) to be connected either as a parallel supply voltage above the voltage to develop a higher light output level or as a series of elements comprising two or more elements (4) to generate a lower light output level above the parallel supply voltage. 1 · • · · 1 1 • · · · 1 ♦ · • M • · · • · · • i * · M I • «· • ·« · · • 97935