ES2962478T3 - Optical group for lighting apparatus and lighting apparatus comprising said optical group - Google Patents

Abstract

A light emission device for lighting apparatus configured to optimize the illumination produced both in the near field, allowing the avoidance of rings or unwanted shadow areas or even portions of terrain that are too intensely illuminated, as well as in the far field, producing lighting that has a direct "throw" and sized to optimize the number of lighting fixtures per unit area. The device uses a lens comprising a first luminous flux entry surface, a second internal reflection surface and a third luminous flux exit surface produced. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Optical group for lighting apparatus and lighting apparatus comprising said optical group

field of invention

The field of the present invention relates to lighting fixtures for ground or ground mounting, in particular to lighting fixtures commonly known as "bollards" or "lighting poles" or "lighting bollards", and to lighting fixtures. lighting commonly known as post-tops.

Background of the technique

Floor-mounted lighting fixtures are known in the prior art. These lighting devices include, for example, devices, commonly known as bollards or lighting posts or lighting bollards, characterized by a reduced height and by the emission of a light beam directed towards the ground, and include lighting devices, known as "post-tops" type, configured for mounting on higher supports and adapted to provide illumination with a wider radius in public and private urban areas.

These devices, hereinafter simply referred to as bollards or post-tops, are commonly used, for example, to illuminate paths or pedestrian areas in urban areas. The aforementioned apparatus generally comprises an optical group comprising, in turn, one or more light sources configured to illuminate a predetermined field of surrounding terrain, or a plurality of optical groups comprising one or more light sources configured to illuminate the same area or different areas of the space surrounding the device. These illuminated areas may belong to a part of the terrain immediately adjacent to the base of the lighting fixture (known as near field, particularly important for bollard-type fixtures) or to a part of the terrain distant from the base of the fixture (known as far field, particularly important for post-top type devices).

Patent document US2009/086480 A1 describes an example of a next-generation lamp that includes a lamp shade, a cylindrical-shaped seat, a light guiding element, a reflective layer and a plurality of circuit boards.

In this type of apparatus available in the prior art, the illumination of the surrounding terrain is never optimal and presents significant uniformity problems. In fact, the light emission from these lighting devices usually creates rings on the floor, or unwanted shadow areas or even illuminated floor areas that are too light and therefore annoying for passers-by.

Furthermore, the luminous efficiency of bollard-type lighting devices is always quite low, since adequate protection must be provided for the fraction of light emission that has wide, almost horizontal angles, to avoid possible glare phenomena to passers-by. . This protection necessarily translates into a substantial decrease in the total luminous efficiency of the device. Other prior art lighting devices are known from WO 2011/065705 A2, DE 102015006258 A1, US 2011/267820 A1 and US 7972036 B2.

Therefore, an object of the present invention is to overcome some of the problems and defects of the prior art and introduce a light emission device and an illumination apparatus capable of improving and optimizing light emission both in the near field and in the distant field.

Compendium of invention

The above objective is achieved by a light emitting device according to claim 1 and a lighting apparatus according to claim 11. Preferred embodiments are subject to the dependent claims. The present description relates to an optical assembly (also called an optical unit) for ground-mounted lighting fixtures, for example, of the type commonly known as a bollard or of the type commonly known as a post-top, used for lighting public spaces and private urban areas. The bollards comprise a main support that has an elongated body with the axis substantially perpendicular to the ground and a base provided with means for anchoring to the ground, and an optical group, located at the upper end of the main support, which in turn comprises a plurality of LED lighting sources arranged so as to produce a direct main emission in a substantially radial direction with respect to the axis of the lighting fixture.

The optical unit according to the present description further comprises means for shaping the light emission of said LED lighting sources, adapted to appropriately direct the resulting light flow towards the ground surrounding the bollard.

Said means for shaping the light emission comprise at least one lens, manufactured and sized to collect the emission from the LED lighting sources and divert it towards the ground.

The lens comprises a plurality of surfaces including an entrance surface facing the LED type illumination sources, an internal reflection surface, associated with at least one reflector, and an exit surface, preferably provided with light mixing means. suitable adapted to optimize the extraction of light from the lens and, at the same time, mix the light emission that comes out of the lens randomly on the surface to be illuminated. These light mixing means help prevent light spots from forming on the surface to be illuminated and also ensure that the base of the bollard is uniformly illuminated without the presence of annoying dark rings.

The lens of the optical group according to the present description can be advantageously configured to emit a light flux only at a certain angle. For this purpose, suitable protective inserts can be inserted into the lens profile to hinder the emission of light in undesired directions. Such inserts may be black and opaque or may be provided with a reflective side to reflect light towards the emitting part of the lens. In another embodiment, the lens may be provided with an opaque screen adapted to cover part of the exit surface of the lens, thus limiting the emission in a certain sector and at a certain angle. This screen can also be done using a layer of matte paint.

The optical group according to the present description can find advantageous application, as mentioned, also in lighting devices other than bollards, for example, in devices commonly known as post-tops for urban lighting applications. , allowing to obtain optimized lighting both in the near field, in the vicinity of the ground support, as well as in the far field, corresponding to the extremes of the polar curve of light emission. Using the optical group according to the present description, the optimized illumination obtained in the near field makes it possible to avoid unwanted rings or shadow areas or even parts of the terrain that are too intensely illuminated and, therefore, annoying. On the other hand, in the far field, it is possible to carry out direct "shot" lighting sized to optimize the number of lighting fixtures per unit area.

Brief description of the drawings

Other features and advantages of the invention will become apparent from the following detailed description given by way of example and not by way of limitation, with the aid of the figures shown in the accompanying drawings, in which:

Figure 1 shows a side view of a preferred embodiment of the optical group, associated with a bollard type lighting apparatus;

Figure 2 shows a sectional view of a preferred embodiment of the optical group, associated with a bollard type lighting apparatus;

Figure 3 shows a detail of the section of a preferred embodiment of the optical group, associated with a bollard type lighting apparatus;

Figure 4 shows a side view of a post-top type lighting apparatus, comprising a preferred embodiment of the optical group;

Figure 5 shows a sectional view of a detail of a preferred embodiment of the optical group, with an indication of the path of part of the light emission produced;

Figure 6 shows a diagram relating to the photometric curve of the light emission produced by a preferred embodiment of the optical group;

Figure 7 shows a detail of a preferred embodiment of the optical group, in which protective inserts are present; and

Figure 8 shows a detail of a preferred embodiment of the optical group, in which an opaque screen is provided, adapted to cover part of the exit surface of the lens.

The following description of exemplary embodiments refers to the accompanying drawings. The same reference numbers in the various drawings identify the same or similar elements. The following detailed description does not limit the invention. The scope of the invention is defined by the attached claims.

Detailed description of the invention

Ground-mounted lighting fixtures, comprising, for example, fixtures commonly known as "bollards" and fixtures commonly known as post-tops, are generally used to illuminate paths or areas. pedestrians in urban areas. To do this, they are designed in such a way that they direct the lighting produced towards the surrounding terrain. However, the lighting produced is often not homogeneous and pleasant for users and presents irregularities, light spots, shadow rings or even emission areas oriented towards the horizontal, which can cause unwanted glare. The optical group 10 according to the present description comprises a structure and an optical compartment optimized to solve the above problems. Said optical group 10 has a structure that allows the emission of light in a radial direction with respect to the axis 15 of the lighting apparatus, substantially perpendicular to the ground. The light emission can have a 360° angle but also reduced angles, to favor illumination in preferred directions.

Referring to the attached figures, a first preferred embodiment of the lighting apparatus according to the present description comprises a main support 22, preferably cylindrical, which in turn comprises, at the lower end, means suitable for fixing it to the ground and, at the upper end, an optical group 10 adapted to generate direct light emission in a radial direction with respect to the axis of the apparatus and directed mainly towards the ground. Preferably, the optical group 10 is configured to emit light at 360° with respect to the axis of the device and is protected by a cover 21.

In other preferred embodiments of the apparatus according to the present description, the main support 22 can have different sections, for example, it can have a square or elliptical section, and the structure of said optical group 10 can be developed on an arc delimited by a selected angle. of a group preferably comprising but not exclusively angles of 90°, 180°, 270° and 360°. In other words, said optical group 10 can be configured to generate a direct light flow of 360° around the axis 15 or according to reduced emission angles, for example at 90°, or at 180°, or at 270°.

Referring to the attached Figure 2, the optical group 10 of the lighting apparatus comprises a central support 11 adapted to house a plurality of LED light emission devices 12 arranged so as to orient the main emission in a substantially radial direction with respect to the axis of the apparatus 15 which is, at least in the cases related to the embodiments provided below, substantially orthogonal to the ground. The LEDs 12 of the above-mentioned plurality of LEDs are preferably equally spaced from each other to make the emitted illumination substantially the same in all directions.

The optical group 10 of the bollard lighting apparatus according to the present description further comprises a lens 13, associated with the LEDs 12 of the aforementioned plurality of LEDs. In more detail, the lens 13 comprises a first entrance surface 14, facing the LEDs 12. The entrance surface 14 of the lens 13 can be straight, curved (concave or convex) or have some shape (for example, in the shape of S), and is preferably inclined, with respect to the axis of the apparatus 15, at a certain angle preferably between 0° and 45°. In a preferred embodiment of the bollard apparatus according to the present description, the angle a is equal to 19° ±10%.

The lens 13 comprises a second internal reflection surface 16, which preferably has a curvature with the concavity turned downwards. This second internal reflection surface 16 is covered at least in part by an external reflector 17 adapted to reflect the part of the light flux emitted by the LEDs 12 that passes through the lens body and leaves the lens itself through said internal reflection surface 16.

Said reflector 17 can be made of plastic or metallic reflective material and the reflective surface facing the lens 13 can be smooth or carved if it is desired to favor the mixing of the reflected light.

Said lens 13 further comprises a third exit surface 18, substantially normal to said axis 15, through which the light flow reflected by the internal reflection surface 16 and by the external reflector 17, leaves the lens and is directed towards the base of the device.

According to the invention, the outer reflector 17 and the lens 13 are, at least in part of their extension, slightly separated from each other, so that a small space is formed between said reflector 17 and said lens 13. In this way, when The light beams emitted by the LEDs 12 propagate inside the lens 13 and reach the internal reflection surface 16, with an angle of incidence with respect to the normal greater than the critical angle Ge = aresen (n2/n1) where n1 and n2 are the refractive indices of the two media through which the light propagates, said beams are totally reflected towards said third exit surface 18 and there is a total reflection inside the lens 13.

In the case in which the angle of incidence with respect to the normal is less than the critical angle Ge, then part of the light beam is refracted towards the external reflector 17 to be reflected back towards the lens 13 and therefore towards said third surface. exit 18.

In a preferred embodiment of the invention, said third exit surface 18 is suitably carved or sculpted to optimize the extraction of light from the lens 13 and, at the same time, direct the emission of light exiting the lens 13 in a random manner. on the surface to be illuminated on the ground. The fact that the third exit surface 18 is carved helps prevent light spots from forming on the surface to be illuminated and ensures that the ground surrounding the base of the bollard is uniformly illuminated without the presence of annoying dark rings. The third exit surface 18 may be fully or partially carved. The relationship between carved surface and smooth surface affects the amount of illumination that is "shot" further with respect to the main support 22 of the lighting apparatus and therefore the extent of the photometric curve of the light emission produced. In a preferred embodiment of the invention described herein, said third exit surface 18 of the lens 13 is partially tooled with the untooled surface less than or equal to 10% of the total surface. Finally, the tooled surface may not be uniform. For example, there may be a greater percentage of raw surface in the portion of the surface closest to the axis 15 of the main support 22 of the lighting fixture.

Finally, preferably, the lens 13 has an extension in the radial direction greater than the extension in the radial direction of the main support 22 of the lighting apparatus. This allows, in the case of bollard type devices, to favor the illumination of the terrain immediately surrounding the base of the main support 22 of the device. The radial extension of the lens 13 may be greater than the extension in the radial direction of the main support 22 even by only a few millimeters, for example, it may be greater than 3 mm.

Referring to the attached Figure 7, to configure said optical group 10, to generate a direct light flow according to reduced emission angles (for example at 90°, or at 180°, or at 270°), the LEDs 12 are arranged in the light emission sector and, in addition, at least one protective insert 23 can be inserted in the profile of the lens 13 to hinder the emission of light towards undesired directions. Said inserts 23 can be black and opaque or can be provided with a reflective side to reflect light towards the light emission sector of the optical group.

In another preferred embodiment, the lens may be provided with an opaque screen 24 adapted to cover part of the exit surface of the lens 18, thus limiting the emission in a certain sector and at a certain angle. Said screen 24 can also be made with a layer of matte paint.

In a preferred embodiment, the optical group 10 may further comprise a recess 19 located immediately below the lens 13. The lower surface 20 of this recess, which is preferably connected to the surface of the main support 22 of the lighting apparatus, is adapted to collect part of the light emission exiting the lens 13 and provide an additional opportunity to shape the emitted light flux. In fact, if said lower surface 20 of the recess 19 is made of opaque black material, it is such that it minimizes the emission of light upwards, increasing the visual comfort of the users.

In another preferred embodiment, said lower surface 20 of the recess 19 is made of white or colored material to have a moderate reflective power that directs part of the incident light emission upward.

Finally, in another preferred embodiment, said lower surface 20 of the recess 19 is made of reflective material, possibly machined with finishes such as to increase the reflective capacity thereof, to achieve a significant overall reflective power, and to direct an important part of the incident light emission upwards.

Claims (17)

1. A light emitting device comprising a support (11) having a central axis (15) adapted to house a plurality of LED light emitting devices (12) arranged to direct the emitted light flux in a substantially radial direction with respect to said axis (15); a lens (13) comprising a first entrance surface (14), oriented towards the LEDs (12) and inclined with respect to said axis (15) at an angle between 0° and 45°; a second internal reflection surface (16) having a curvature with the concavity turned downward and covered, at least in part, by a reflector (17); a third exit surface (18), substantially normal to said axis (15), adapted to emit the light flow coming out of the lens (13), characterized in that the reflector (17) and the lens (13) are separated with each other at least in part of their extension, to form a space between said reflector (17) and said lens (13). 2. A device according to the preceding claim, characterized in that said reflector (17) is made of plastic or metal reflective material. 3. A device according to the preceding claim, characterized in that the reflective surface of said reflector (17) comprises processing adapted to mix the reflected light. 4. A device according to one or more of the preceding claims, characterized in that at least part of said third exit surface (18) comprises processing adapted to mix the light emerging therefrom. 5. A device according to the preceding claim, characterized in that part of said third exit surface (18) that comprises a processing adapted to mix the light that exits therefrom, is greater than or equal to 90% of the total. 6. A device according to one or more of claims 4 to 5, characterized in that said processing is not uniform. 7. A device according to one or more of the preceding claims, characterized in that said angle a is equal to 19° ±10%. 8. A device according to one or more of the preceding claims, characterized in that it comprises at least one protective insert (23) inserted in the lens (13) to hinder the emission of light towards undesired directions. 9. A device according to one or more of the preceding claims, characterized in that said lens (13) comprises an opaque screen (24) adapted to cover part of the exit surface (18) of the lens (13), limiting thus the emission of light at a certain angle. 10. A device according to the preceding claim, characterized in that said opaque screen (24) is made by means of a layer of matte paint. 11. A lighting apparatus comprising a support (22) having a central axis (15); ground fixing means associated with the lower end of said support (22); an optical unit (10) associated with the upper end of said support (22) and adapted to generate direct light emission mainly towards the ground, characterized in that said optical unit (10) comprises a light emission device according to one or more of claims 1 to 10. 12. An apparatus according to the preceding claim, characterized in that the structure of said optical unit (10) is developed on an arc delimited by an angle selected from a group comprising angles of 90°, 180°, 270° and 360°. °. 13. An apparatus according to one or more of claims 11 to 12, characterized in that the optical unit (10) comprises a cavity (19) located immediately below the lens (13) and attached to the support surface (22). ), said cavity (19) comprising a lower surface (20) adapted to collect part of the light emission that comes out of the lens (13). 14. An apparatus according to the preceding claim, characterized in that said lower surface (20) of the cavity (19) is made of an opaque black material. 15. An apparatus according to claim 13, characterized in that said lower surface (20) of the cavity (19) is made of a white or colored material. 16. An apparatus according to claim 13, characterized in that said lower surface (20) of the cavity (19) is made of a reflective material. 17. An apparatus according to one or more of claims 11 to 16, characterized in that the lens (13) has an extension in the radial direction, which is greater than the extension, in the radial direction, of the support (22).