DESCRIPTION

FIELD OF THE INVENTION

The present invention relates to a lighting system with variable aperture, in particular with variable angle of radiation.

STATE OF THE ART

The LEDs (or light emitting diodes) for lighting available on the market offer a wide range of choices in terms of colour, intensity and angle of radiation. The colour as well as the lighting intensity ("Dimmable LEDs") can also be dynamically changed during the operation of the LED ("RGB LED"), while the angle of radiation is chosen at the time of purchase, being determined in invariable manner in the manufacturing phase of the light source.

The angle of radiation can be defined as the solid angle within which the light intensity is maintained above 50% of the maximum value. This lighting engineering parameter is typically very broad, for example around 100-120°.

In fact, optimal angles of radiation are known for various lighting engineering projects, for example between 10° and 20° for accent lighting on specific objects, such as artworks in a museum or products displayed in a showcase; between 30° and 40° for the lighting of commercial environments or restaurants, over 50° for the general lighting of environments, for example in offices and corridors.

It is known to associate a small plastic lens to a LED directly on the LED chip. Professional control systems for this lighting engineering parameter, realised by coupling a motorised zoom with a light source, are further known and marketed. However, these systems, used in particular in the entertainment field, are characterized by considerable dimensions, high energy costs and consumption, as well as by the emission of noise due to the operation of the common gearmotor that moves the optical system.

SUMMARY

In a lighting engineering project, there might be the need to customize the radiation according to the environment in which the light source is installed or to the needs of use of the person living there (which, however, may also vary over time, for example during of the years but also of the hours of the day).

The general object of the present invention is to provide a lighting system, in particular with LED, with variable aperture.

A first more specific object of the present invention is to provide a lighting system, in particular with LED, with a variable angle of radiation.

A second more specific object of the present invention is to provide a lighting system, in particular with LED, with a radiation pattern that can be dynamically modified during operation.

A third more specific object of the present invention is to provide a lighting system, in particular with LED, with overall dimensions similar to those of the light source, consisting in particular of one (or a few) LED(s).

A fourth more specific object of the present invention is to provide a simple and compact lighting system which can assume two or more different angles of radiation based on the number of different zoom positions assumed by a lens of the lighting system.

A fifth more specific object of the present invention is to provide a dynamic lighting system which can assume two or more different operating conditions (corresponding to different angles of radiation) while being noiseless in passing from one operating condition to another.

A sixth more specific object of the present invention is to provide a dynamic lighting system which can assume two or more different operating conditions (corresponding to different angles of radiation), while being at low electrical consumption in relation to the passage from one operating condition to another and to the maintenance of the operating conditions.

This general purpose as well as these and other more specific purposes are achieved thanks to what is expressed in the appended claims which form an integral part of the present description. The object of the present invention is a lighting system having the technical characteristics set out in the appended claim 1. In particular, the lighting system comprises: a light source, an optical assembly having a lens located opposite to the light source and adapted to make a movement at least partially of translation along its optical axis, and a mechanical assembly adapted to cause rotation of a rotor of the optical assembly and consequently translation of the lens.

Advantageously, the mechanical assembly is adapted to cause translations of the lens both towards and away from the light source. The mechanical assembly can be operated repeatedly and cause successive translation steps, which are first with towards- and then away-movement; a translation step can correspond to each actuation. The translation steps according to a first direction can be of the same first entity; the translation steps according to a second direction can be of the same second entity; the second entity is a multiple of the first entity.

Advantageously, the mechanical assembly comprises a slide adapted to run along a guide in a first direction and in a second direction cyclically between two ends of the guide and to cause rotation of the rotor (and hence translation of the lens) only when the slide runs in the first direction and not in the second direction. The slide can be operated by one or two actuator means, in particular at least one electrical and/or elastic linear actuator. Advantageous aspects of the present invention are set out in the appended dependent claims.

As it will be better understood from the following description, the lighting system with variable aperture according to the present invention is particularly advantageous because, among other things, it is suitable for communicating in a unidirectional or bidirectional way with an external electronic device (for example a lighting control point) and/or an external electronic device (for example a home automation system) for changing its radiation pattern.

LIST OF FIGURES

The present invention shall become more readily apparent from the detailed description that follows to be considered together with the accompanying drawings in which:

Fig. 1 shows an exploded view of an example of a lighting system with variable aperture made in accordance with the present invention,

Fig. 2 shows the example of embodiment of Fig. 1 assembled, Fig. 3 shows the base and the mechanical assembly of the example of embodiment of Fig. 1,

Fig. 4 shows the base and the optical assembly of the example of embodiment of Fig. 1,

Fig. 5 shows the example of embodiment of Fig. 1 in a rest phase, Fig. 6 shows the example of embodiment of Fig. 1 in an activation phase,

Fig. 7 shows an example of some phases of the movement of the support and of the rotor partially sectioned of the example of embodiment of Fig. 1.

As can be easily understood, there are various ways of practically implementing the present invention which is defined in its main advantageous aspects in the appended claims and is not limited either to the following detailed description or to the appended drawings.

DETAILED DESCRIPTION

With reference to Figs. 1-7, an example of a lighting system with variable aperture subject-matter of the present invention is generally indicated with the reference number 1000.

With non-limiting reference to Figs. 1-2, the lighting system 1000 comprises: a light source 1100, in particular a LED; an optical assembly 100 having a lens 10 adapted to make a movement at least partly of translation along its optical axis X; - a mechanical assembly 200 adapted to cause the rotation of a rotor 120 of the optical assembly 100; wherein said mechanical assembly (200) comprises: a slide (220) adapted to run along a guide (225) in a first direction and in a second direction (opposite to the first direction) between two ends and to cause rotation of said rotor (120) only when said slide (220) runs in said first direction, and a first actuator means (210), in particular of the linear type, adapted to cause slidings of said slide (220) in said first direction and in said second direction between said two ends.

Typically, the LED 1100 is installed on a support 500, in particular a support made of aluminum which has the function of adequately dissipating the heat generated during operation. Furthermore, this support 500 houses the electrical contacts 310 on which the power supply wires are soldered and is provided with slots or holes for assembly to the rest of the light fixture. In this way the light source is bound, generally by means of screws, to the rest of the light fixture, fixing a direction and a lighting area of the light beam.

As shown in Fig. 1 and 2 the lighting system subject-matter of the present invention is adapted to be installed in a foldable manner on the support 500 of the light source 1100 so as to define a movement at least partially of translation of the lens 10 with respect to the light source 1100.

The optical assembly 100 and the mechanical assembly 200 are mounted on a base 300 which is in turn adapted to be mounted on an electronic board 400 which can, for example, but not necessarily, trace the shapes and holes of the FED support 500 in such a way to make use of the same screws for mounting. Advantageously, suitable spacers are used for mounting the electronic board 400 on the support 500. The electronic board 400 houses the components and circuitry suitable for receiving the commands for activating the mechanical assembly 200 adapted to move the lens. Advantageously, the electronic board 400 is positioned in front of the light source and is provided with at least two contacts 312, adapted to electrically connect the electronic board 400 to the electrical contacts 310 of the light source 1100, so that it is powered by the same line that powers the FED 1100. Typically, the support 500 of the FED 1100 is provided with two power pads for the positive pole and two power pads for the negative pole, while the power wires of the LED 1100 are soldered on a single pad with the positive and on one single pad with the negative, thus leaving the same number of pads free.

In the preferred embodiment, the lighting system 1000 can interface with an electronic system without requiring additional wiring but by exploiting, for example, the pre-existing power supply cables of the LED or by communicating via radio. The communication protocol that will be implemented can be unidirectional, i.e., adapted to receive commands only, or bidirectional, and therefore also adapted, for example, to transmit a confirmation of receipt of the command, information on the position of the lens or on the status of the system.

The base 300 and the electronic board 400 have a hole 301 at the optical axis X of the lens 10 to allow the passage of the light produced by the light source 1100. With reference to Fig. 3, the base 300 also has a guide 225, in particular a linear guide, for moving part of the mechanical assembly 200 and a seat for mounting the optical assembly 100. Preferably the seat for mounting the optical assembly 100 comprises at least two protrusions 304, preferably four, to ensure the alignment of the optical axis X of the lens 10 with the axis of the hole 301.

The mechanical assembly 200 comprises a slide 220, adapted to run along the guide 225, in particular adapted to run between two ends of the guide 225; the slide 220 can run along the guide 225 in a first direction, in which the slide 220 moves from a first end of the guide 225 to a second end of the guide 225, and in a second direction (opposite to the first direction), in which the slide 220 moves from a second end of the guide 225 to a first end of the guide 225.

The mechanical assembly 200 further comprises a first actuator means 210, in particular of the linear or substantially linear type, adapted to cause the sliding of the slide 220 in the first direction along the guide 225. In the preferred embodiment, the actuator means 210 consists of a pre-formed elastic member, typically but not necessarily in the form of a helical spring, made of a shape memory metal alloy (SMA), for example a Ni-Ti, Cu-Zn-Al, Cu-Al-Ni alloy or other alloys. These alloys are characterized in that they recover the previously modelled shape, by means of suitable thermal cycles during manufacturing, when crossed by electric current. The actuator means 210 has a first end connected to the slide 220 and a second end fixed to a suitable anchoring seat obtained on the base 300, in particular on the guide 225.

The mechanical assembly 200 further comprises a second actuator means 215 adapted to cause the sliding of the slide 220 in the second direction opposite to that caused by the first actuator means 210. Preferably the second actuator means 215 is constituted by an elastic member, typically but not necessarily a spring, made of a metallic material, in particular of steel.

The second actuator means 215 has a first end connected to the slide 220, in an opposite position with respect to the connection side of the first end of the actuator means 210, and a second end fixed to a suitable anchoring seat obtained on the base 300, in particular on the guide 225.

With reference to Fig. 4, the optical assembly 100 comprises: a rotor 120, adapted to rotate around the optical axis X and hollow so that light emitted from said light source (1100) can reach said lens (10), a support 110 on which the lens 10 is mounted, adapted to translate in the direction of the optical axis X due to rotation of the rotor 120 and hollow so that light emitted from said light source (1100) can reach said lens (10).

Typically, the support 110 and the rotor 120 have a substantially cylindrical shape and the support 110 is inserted at least partially in the rotor 120. Consequently, the support 110 and the rotor 120 share the same revolution axis, constituted by the optical axis X. In other words, the support 110 and the rotor 120 are coaxial.

In the preferred embodiment, the rotor 120 has a gear 122 on the external cylindrical surface, in particular a gear having oblique teeth, that is the profile of which is shaped like a "saw tooth" in which a first flank of a tooth is shorter in length than a second flank of a tooth. The mechanical assembly 200, in particular the slide 220, acts on the gear 122. The slide 220 is in fact arranged to abut with the gear 122, causing the rotation of the rotor 120. In particular, the slide 220 comprises a first rigid portion adapted to abut with the first flank of a tooth of the gear 122 (the shorter flank) and an elastic portion, connected to the first rigid portion, adapted to deform reversibly so that the first rigid portion is allowed to slide along the second flank of a tooth of the gear 122 (the longer flank), as will be better explained below. The number of teeth that make up the gear 122 is a customizable parameter, bearing in mind that the number of teeth is double with respect to the number of zoom positions assumed by the lens 10 corresponding to as many angles of radiation, i.e., the number of translations performed by the support 110. In the case of two positions, they are reached alternately at each activation of the first actuator means 210; in the case of N positions, with N>2, they are reached in sequence one by one at each activation of the first actuator means 210.

For greater clarity purposes, in Fig. 5 and in Fig. 6 respectively a rest phase and an activation phase of the first actuator means 210 are shown. In the rest phase, the first actuator means 210 is stressed by a traction force caused by the return force of the second actuator means 215, determining a first position of the slide 220 next to the anchoring point of the second actuator means 215, i.e., at the first end of the guide 225.

In the activation phase, the first actuator means 210 is crossed by electrical current through the power supply of the electronic board 400 and recovers the shape memorized during the manufacturing phase; in particular, the first actuator means 210 contracts or shortens, exerting a traction force on the second actuator means 215, causing it to extend. Consequently, the slide 220 moves along the guide 225 in the first direction, reaching a second position located near the anchoring point of the first actuator means 210, that is, at the second end of the guide 225. Once the electrical supply of the first actuator means 210 has been completed, the first actuator means 210 then returns to a rest phase and the slide 220 returns to the first end of the guide 225, near the anchoring point of the second actuator means 215.

It should be noted that when the slide 220 moves along the guide 225 in the first direction, the first rigid portion of the slide 220 abuts with the first flank of a tooth of the gear 122 causing the rotation of the rotor 120, whereas when the slide 220 moves along the guide 225 in the second direction, the first rigid portion of the slide 220 runs along the second flank of a tooth of the gear 122 through the deformation of the elastic portion of the slide 220; this mechanism is commonly known as ratchet device.

In a preferred embodiment, the slide 220 is made of plastic material and the first rigid portion of the slide 220 consists of a protrusion, while the elastic portion of the slide 220 consists of a thinning of the first rigid portion, capable of deforming according to certain operating conditions.

In particular, the first rigid portion and the elastic portion are connected to each other.

Advantageously, the elastic portion is further connected to a second rigid portion of the slide 220 adapted to run along the guide 225 and on which the actuator means 210 and 215 act; in particular, the actuator means 210 and 215 are connected to opposite sides of the second rigid portion, so as to cause the slide 220 to run in a first direction and in a second direction along the guide 225.

Advantageously, the protrusion and the thinning are suitably sized so that, during the activation phase of the first actuator means 210, the protrusion can abut with the first flank of a tooth of the gear 122 and transfer a rotation movement to the rotor 120 while, during the rest phase of the first actuator means 210, the protrusion can slide on the external surface of the rotor 120 without moving it, in particular sliding on the second flank of a tooth of the gear 122, by means of the deformation capacity of the thinning. In Fig. 7 it is shown an example of some phases of the movement of the support and of the rotor partially sectioned in a first preferred embodiment. The support 110 further has a slot 113 defined by a closed path and determining a screw coupling between the support 110 and the rotor 120. The slot 113 therefore extends continuously on the external cylindrical surface of the support 110 facing the rotor 120, comprising at least a first section arranged in an inclined direction with respect to the optical axis X and at least a second section arranged in a direction parallel or substantially parallel with respect to the optical axis X; for example, the first section may have an inclination in a range comprised, for example, between 10° and 50° with respect to the direction of the optical axis X, and the second section may have an inclination in a range comprised, for example, between 0° and 5° with respect to the direction of the optical axis X. Advantageously, an elastic means 111 is connected to a second end of said support 110, in particular a steel spring, adapted to cause a translation of said support 110 in the opposite direction with respect to the translation caused by the mechanical assembly 200. Advantageously, on the same end of the support 110 to which the elastic means 111 is connected, there are at least two protrusions 112, in particular two pegs, developing in the direction of the optical axis X which, by sliding in as many holes 303 present on the base 300, prevent the rotation of the support 110 but leaving it free to translate along the direction of the optical axis X.

The rotor 120 further has at least one protrusion 123, in particular a peg, on the internal cylindrical surface facing the support 110, adapted to slide in the slot 113. By means of the rotation of the rotor 120 caused by the slide 220, the protrusion 123 constrained thereto slides in the slot 113 causing a translation movement of the support 110 along the direction of the optical axis X.

With reference to Fig. 7, according to a preferred embodiment, the translation movement of the support 110 originates from an initial position in which the protrusion 123 occupies the portion of the slot 113 closest to the base. At this portion, the lens 10 is at a maximum distance from the light source 1100. During each actuation of the first actuator means 210, the protrusion 123 progressively runs along the slot 113, in particular it runs for a portion of the first inclined section upon each actuation of the first actuator means 210, assuming a number of positions along the slot 113 determined by the number of teeth of gear 122. Each run portion of the first inclined section causes a translation of the support 110 and progressively decreases the distance between the lens 10 and the light source 1100; in other words, the lens 10 mounted on the support 110 approaches the light source 1100, with a consequent compression of the elastic means 111. Once the lens 10 is at the point of minimum distance from the light source 1100, in other words when the rotor 120 has completed a 360° turn (or a submultiple of 360° if there are more inclined sections) around its optical axis X, the protrusion 123 is located at the second section of the slot 113 arranged in a direction parallel or substantially parallel with respect to the optical axis X and the elastic means 111, previously compressed, is free to extend causing the translation of the lens 10 into the initial position. In a second preferred embodiment, the support 110 may not be connected to any elastic means and the return of the lens 10 to the initial position is ensured by an appropriate conformation of the slot 113 present on the external cylindrical surface of the support 110. In particular, in this embodiment the path of the slot 113 comprises at least a staircase-shaped section which defines at least a position of metastable equilibrium such that, at each actuation phase of the first actuator means 210, the protrusion 123 reaches such position of metastable equilibrium and remains there until the subsequent activation phase of the first actuator means 210; alternatively, the path of the slot comprises at least a ramp-shaped section which could have positions of metastable equilibrium thanks to friction. Advantageously, the slot 113 comprises at least a first ascending section and at least a second descending inclined section, where said first section and said second section form a closed path. Advantageously, at each section of the path, the protrusion 123 can assume at least a position of metastable equilibrium thanks to the friction between slot 113 and protrusion 123, which is maintained until the subsequent actuation phase of the first actuator means 210.

In a further alternative embodiment, the slot 113 extends on the internal cylindrical surface of the rotor 120 facing the support 110 and on the external cylindrical surface of the support 110 facing the rotor 120 there is at least one protrusion 123, in particular a peg, adapted to slide in slot 113. Basically, successive (typically identical between them) actuations of the slide cause axial movements of the optical assembly which lead it to cyclically assume different axial positions with respect to the light source.