EP3239591A1

EP3239591A1 - An illumination device with adjustable light intensity distribution

Info

Publication number: EP3239591A1
Application number: EP16167360.3A
Authority: EP
Inventors: Tobias Schmidt; Stephan MALKMUS
Original assignee: Osram GmbH
Current assignee: Osram GmbH
Priority date: 2016-04-27
Filing date: 2016-04-27
Publication date: 2017-11-01

Abstract

An illumination device comprises a LED light source assembly (1) including a plurality of LED light sources (11), and an optical assembly (2) including at least one optical element (21) which is connected to the LED light source assembly (1) for shaping the intensity distribution of the light emitted from the plurality of LED light sources (11). A means is provided for generating at least a first light intensity distribution pattern and a second light intensity distribution pattern with the same LED light source assembly (1) and the same optical assembly (2).

Description

The present invention relates to an illumination device with adjustable light intensity distribution. In particular, the present invention relates to an illumination device capable of providing different light intensity distribution patterns with the same device components.

BACKGROUND OF THE INVENTION

Illumination devices are used in a variety of lighting applications, including office lighting, task lighting, cabinet lighting, street lighting, down-lighting, etc. Conventionally, an illumination device is configured to provide a particular light intensity distribution for a particular lighting application, for example, some illumination devices are designed for generating a direct light distribution pattern, which has the strongest light intensity in the middle, and the gradually decreased light intensity from the middle to two sides, e.g. cosine light distribution pattern, and some illumination devices are designed for generating a batwing light distribution pattern, which has greater light intensity at both sides than in the middle.
If two or more types of light intensity distributions are required in an application, it is necessary to change optics of the illumination device, such as the reflector or/and the lens to generate different light distribution patterns. Thus, low efficiency and complex structure are resulted in.

SUMMARY OF THE INVENTION

The present invention seeks to provide an illumination device which can realize different light intensity distributions with the same device components. In particular, one object of the present invention is to provide an illumination device which can generate both direct and batwing light intensity distributions with the same optical assembly and the same LED light source assembly.
The illumination device according to the present invention comprises a LED light source assembly having a plurality of LED light sources, and an optical assembly having at least one optical element, which is connected to the LED light source assembly for shaping the light intensity distribution of the light emitted from the plurality of LED light sources. In particular, the optical assembly is adjustable connected with the LED light source assembly. Adjustable connection means that the optical assembly can be positioned or oriented with respect to the LED light source assembly in different ways. A means is provided for generating at least a first light intensity distribution pattern and a second light intensity distribution pattern with the same LED light source assembly and the same optical assembly.
The illumination device is therefore able to generate different light intensity distribution patterns without the need to replace the LED light source assembly, or to replace the optical assembly. In practical applications where different light intensity distribution patterns are required, this kind of illumination device has great advantages because only a simple adjustment on itself is needed to meet diverse demands. Production is more efficient, as the process of manufacturing different LED light source assemblies or optical assemblies is omitted.
Preferably, a distance between the LED light source assembly and the optical assembly along a principal axis of emittance of the light source assembly is constant while generating at least the first light intensity distribution pattern and the second light intensity distribution pattern. The optical element could be a refractive optical element, such as a lens, or a reflective optical element, such as a reflector. Each LED has a light emitting surface. Each point of the light emitting surface of an LED has a certain luminous emittance. The centre of emittance of the LED is defined as the weighted average of all points of the light emitting surface of the LED, where the weight of each point is its corresponding luminous emittance. An LED emits light into a certain range of directions. Each of these directions can be described as a unit vector, having a certain luminous intensity associated with it. The principal emittance direction of the LED is defined as the weighted average of all these vectors, where the weight of each vector is its corresponding luminous intensity. In the special case of a rotationally symmetric intensity distribution, the principal emittance direction points along the axis of symmetry. The principal axis of emittance of an LED is defined as the axis that goes through the centre of emittance of the LED and is aligned with the principal emittance direction of the LED. The midpoint of a lens is defined as its centroid, also called geometric center. These terms are accordingly defined for other light sources or for sets of several LEDs. As the distance between the LED light source assembly and the optical assembly does not need to be changed along the principal axis of emittance of the light source assembly, the illumination device could have a simple and compact structure.
It is preferable that the optical assembly comprises a plurality of optical elements, and each of the optical elements corresponds to one of the LED light sources, respectively. "Correspond" means that each optical element is assigned to a LED light source, so that the light emitted from a LED light source basically reaches the optical element assigned to it. No light or only a very small part of light, e.g. 10%-30%, may reach other optical elements. In this way, the optical assembly and the LED light source assembly may be constructed as a wide range illumination product.
It is further preferable that the means for generating at least the first light intensity distribution pattern and the second light intensity distribution pattern comprises a means of adjusting a distance between a principal axis of emittance of a light source and the midpoint of the optical element corresponding to this light source. Preferably, the adjustment of the position of the midpoint of the optical element with respect to the centre of emittance of the light source has only a small directional component parallel to this axis of emittance, which means that the directional component parallel to this axis of emittance is zero or much shorter than a directional component perpendicular to this axis of emittance. For example the directional component parallel to said principle axis of emittance is smaller than 10% of the component perpendicular to this axis of emittance.
Preferably, the LED light sources are arranged in a first circle C1. More precisely, the centres of emittance of the LED light sources are arranged in the first circle C1. In fact, a certain deviation is allowed, so that centres of emittance of the LED light sources are generally arranged along the circle C1. The optical elements are preferably arranged in a second circle C2. The second circle C2 is more precisely formed by the geometrical centres of the optical elements. Again, a deviation between the geometrical centres of the optical elements and the circle C2 is allowed. The first circle C1 is corresponding to the second circle C2. It means that if the LED light source assembly and the optical assembly are mounted together, the plane of the first circle C1 and the plane of the second circle C2 are parallel and both perpendicular to a central axis X passing through the centers of circle C1 and circle C2. In this configuration, rotation of the optical assembly about the centre axis X results in the lateral shifting of the optical elements with respect to the light sources. Preferably, the distance between the centre of emittance of a LED light source and the geometrical centre of its corresponding optical element is the same as the distances between the centres of emittance of the other LED light sources and the geometrical centres of the optical elements corresponding to these other LED light sources. The first circle C1 and the second circle C2 may have the same radius, so that the centre of emittance of a LED light source and the geometrical centre of its corresponding optical element could be moved relatively to an orientation in which a line X' passing through them is parallel to the central axis X. In this case, the first light intensity distribution could be easily generated. The first circle C1 and the second circle C2 may also have different radii, as long as the smallest distance between the centre of emittance of a LED light source and the geometrical centre of its corresponding optical element is small enough to realize the first light intensity distribution.
The LED light source assembly and/or the optical assembly may be rotatable around the central axis X. Thus an angle θ formed by a first line L1 passing through the center of C1 and the LED light source, as well as a second line L2 which passes through the center of C1 and is parallel to a third line L3 passing through the center of C2 and the optical element corresponding to the light source is adjustable. Therefore, the light distribution pattern is determined by the angle θ, which makes it easy to control. Advantageously, the centres of emittance of the LED light sources may be evenly arranged in a first circle C1 and the geometrical centres of optical elements may be evenly arranged in a second circle C2, so that with the relative rotation between the optical assembly and the LED light source assembly over a certain angle, each LED light source may be corresponding to another optical element but could still generate the same light distribution. In this way, if the rotation angle for generating a particular light distribution pattern is too small to be mechanically realized, other larger rotation angles may also generate the same pattern. The adjustment could be further simplified.
Preferably, the LED light sources are arranged on the LED light source assembly in a fourth line L4 and a fifth line L5 parallel to the fourth line L4. More precisely, the centres of emittance of LED light sources are arranged in the fourth line L4 and the fifth line L5.
Preferably, the optical assembly may comprise a first optical sub-assembly 2a and a second optical sub-assembly 2b. Half of the optical elements, or more precisely, geometrical centres of the half of optical elements are arranged on the first optical sub-assembly 2a in a sixth line L6, and the other half of the optical elements, or more precisely, geometrical centres of the other half of optical elements are arranged on the second optical sub-assembly 2b in a seventh line L7. Thus, if the optical sub-assemblies 2a, 2b are mounted together with the LED light source assembly, each line of optical sources is corresponding to one line of optical elements. "Corresponding" is understood as each optical element is assigned to a LED light source, so that the light emitted from a LED light source basically reaches the optical element assigned to it. No light or only a very small part of light, e.g. 10%-30% may reach other optical elements. While being mounted with the LED light source assembly, the orientations of the two optical sub-assemblies could be changed, which may realize different patterns of light distribution.
The first optical sub-assembly and the second optical sub-assembly may be connected with the LED light source assembly in a first orientation, so that the sixth line L6, the seventh line L7 are both parallel to the fourth line L4 and the fifth line L5, and a first distance is formed between each of the principal axes of emittance of the light sources and the midpoint of the corresponding optical element, which results in the first light intensity distribution pattern.
The first optical sub-assembly and the second optical sub-assembly may also be connected with the LED light source assembly in a second orientation, so that the sixth line L6, the seventh line L7 are both parallel to the fourth line L4 and the fifth line L5, and a second distance larger than the first distance is formed between each of the principal axes of emittance of the light sources and the midpoint of the corresponding optical element, which results in the second light intensity distribution pattern.
It is preferable that the means for generating at least the first light intensity distribution pattern and the second light intensity distribution pattern comprises a means of changing luminous flux of the plurality of LED light sources. Therefore, patterns of light distribution could be electrically controlled.
Preferably, the plurality of LED light sources comprises at least a first group of LED light sources and a second group of LED light sources. The luminous flux of each group could be separately controlled.
Preferably, the first light intensity distribution pattern and the second light intensity distribution pattern are realized by adjusting the luminous flux ratio between the first group of LED light sources and the second group of LED light source. The luminous flux of the first group as a whole may be adjusted to be the same as the luminous flux of the second group as a whole. Thus, the first light intensity distribution could be realized. When the ratio of luminous flux between the first group and the second group is a first value, the first light distribution could also be realized. When the ratio of luminous flux between the two groups of LED light sources is changed to a second value, the second light intensity distribution pattern may be realized. In this way, a structural change of the illumination device is avoided. In a situation that the structure of an illumination device cannot be changed, this kind of illumination devices has great advantages.
The first light intensity distribution pattern may be direct light distribution pattern. The second light intensity pattern may be batwing light distribution pattern. They are two commonly used light distribution patterns. Other patterns for certain applications may also be generated by the illumination device.
Each optical element may comprise a lens or a reflector. The optical assembly may comprise lenses or reflectors or both.
Each LED light source may comprise one LED, or more than one LED. The LEDs could be all kinds of LEDs, such as CoB-LED, SMD-LED. Thus, the illumination device could be widely used.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1: is a perspective view of an illumination device of a first embodiment;
Fig. 2: is a perspective view of a LED light source assembly of the first embodiment;
Fig. 3: is a perspective view of an optical assembly of the first embodiment;
Fig. 4: is a top view of the first embodiment in a first orientation;
Fig. 5: is a polar plot of light intensity distribution realized by the first embodiment in the first orientation;
Fig. 6: is a Cartesian plot of light intensity distribution realized by the first embodiment in the first orientation;
Fig. 7: is a top view of the first embodiment in a second orientation;
Fig. 8: is a polar plot of light intensity distribution realized by the first embodiment in the second orientation;
Fig. 9: is a Cartesian plot of light intensity distribution realized by the first embodiment in the second orientation;
Fig. 10: is a top view of the first embodiment in a third orientation;
Fig. 11: is a polar plot of light intensity distribution realized by the first embodiment in the third orientation;
Fig. 12: is a Cartesian plot of light intensity distribution realized by the first embodiment in the third orientation;
Fig. 13: is a perspective view of a LED light source assembly of another modification of the first embodiment;
Fig. 14: is a top view of the LED light source assembly of the modification of the first embodiment;
Fig. 15: is a perspective view of the illumination device of a second embodiment;
Fig. 16: is a perspective view of a LED light source assembly of the second embodiment;
Fig. 17: is a cross section view of the LED light source assembly of the second embodiment;
Fig. 18: is perspective view of an optical assembly of the second embodiment;
Fig. 19: is a cross section view of the optical assembly of the second embodiment;
Fig. 20: is a top view of the second embodiment in a first orientation;
Fig. 21: is a cross section view of the second embodiment in the first orientation;
Fig. 22: is a polar plot of light intensity distribution realized by the second embodiment in the first orientation;
Fig. 23: is a Cartesian plot of light intensity distribution realized by the second embodiment in the first orientation;
Fig. 24: is a top view of the second embodiment in a second orientation;
Fig. 25: is a cross section view of the second embodiment in the second orientation;
Fig. 26: is a polar plot of light intensity distribution realized by the second embodiment in the second orientation;
Fig. 27: is a Cartesian plot of light intensity distribution realized by the second embodiment in the second orientation;
Fig. 28: is an exploded view of another modification of the second embodiment;
Fig. 29: is an exploded cross section view of the modification of the second embodiment in a first orientation;
Fig. 30: is an exploded cross section view of the modification of the second embodiment in a second orientation;
Fig. 31: is a top view of a third embodiment;
Fig. 32: is a cross section view of the third embodiment;
Fig. 33: is a polar plot of light intensity distribution realized by the third embodiment when only inner LED light sources are switched on;
Fig. 34: is a Cartesian plot of light intensity distribution realized by the third embodiment when only inner LED light sources are switched on;
Fig. 35: is a polar plot of light intensity distribution realized by the third embodiment when only outer LED light sources are switched on;
Fig. 36: is a Cartesian plot of light intensity distribution realized by the third embodiment when only outer LED light sources are switched on.

DETAILED DESCRIPTION OF THE INVENTION

Example embodiments that incorporate one or more aspects of the invention are described and illustrated in the drawings. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. The following detailed description, therefore, is not to be taken in a limiting sense. The same reference numbers are used to refer to the same or like parts or components.
Fig. 1 shows a perspective view of an illumination device 100 of a first embodiment according to the present invention. The illumination device 100 comprises a LED light source assembly 1 and an optical assembly 2 which is connected to the LED light source assembly 1. The LED light source assembly 1 comprises a plurality of LED light sources 11. The optical assembly 2 comprises a plurality of lenses 21, each of which is assigned and corresponds to one LED light source 11. Light emitted from each LED light source 11 exits after passing through its corresponding lens 21.
FIG. 2 is a perspective view of the LED light source assembly 1 of the first embodiment. The LED light source assembly 1 comprises a base plate 1'. In this embodiment, the LED light sources 11 are arranged evenly in a first circle C1 on the base plate 1', or more specifically, the centres of emittance of the LED light sources 11 are arranged evenly in the first circle C1. The centre of emittance of a LED light source is understood as the weighted average of all points of the light emitting surface of the LED, where the weight of each point is its corresponding luminous emittance. An aperture 12 is placed in the center of the first circle C1. A curved groove 13 is formed within the first circle C1. Optionally, the curved groove 13 could also be formed in other places on the base plate 1'.
Fig. 3 is a perspective view of the optical assembly 2 of the first embodiment. The optical assembly 2 is a lenses assembly 2, which is substantially shaped as a disk. A plurality of lenses 21 are arranged evenly on one side of the disk in a second circle C2 (see Fig. 1 ), or more specifically, the geometrical centres of the lenses 21 are arranged evenly in a second circle C2. In addition, two pins 22, 23 are placed on the other side of the disk and extend away from the disk, wherein the pin 22 is located in a position corresponding to the center of the circle C2. Optionally, the lenses assembly 2 could be configured to have other shapes.
When the lenses assembly 2 is assembled together with the base plate 1', the pin 22 is being inserted into the aperture 12, and the pin 23 is being inserted into the curved groove 13. With the sliding of the pin 23 in the curved groove 13, the lenses assembly 2 can be rotated around the pin 22. As shown in Fig. 4 , which illustrates a top view of the first embodiment in a first orientation, when the lenses assembly 2 is rotated to the first position, the geometrical centre of each lens is aligned with the centre of emittance of its corresponding LED light source. Thus, light emitted from the lenses assembly 2 forms a direct light distribution. FIG. 5 shows a polar plot of light intensity distribution realized in the first orientation. Fig. 6 shows a Cartesian plot of light intensity distribution realized in the first orientation. From the polar plot, it can be seen that the direct light distribution is generated in this orientation.
In the first embodiment shown above, the first circle C1 and the second circle C2 have the same radius. However, they may also have different radii, as long as different patterns of light intensity distribution including direct light distribution and Batwing light distribution could be realized with different relative positions between the LED light source assembly 1 and the optical assembly 2.
With further sliding of the pin 23 in the curved groove 13 to a second position, as shown in Fig. 7 , a small spacing is formed between the geometrical centre of each lens 21 and the centre of emittance of its corresponding LED light source 11. Or in other words, a rotation angle θ1 is formed between a radius passing through the center of C1 and the centre of emittance of a LED light source 11, as well as a radius which passes through the center of C1 and is parallel to a radius passing through the center of C2 and the geometrical centre of the lens 21 corresponding to the light source. Detected at the same position, the polar plot of light intensity distribution and the Cartesian plot of light intensity distribution are illustrated in Fig. 8 and Fig. 9 , respectively. The light intensity distribution shown in Fig. 8 is substantially a direct light distribution. However, the FWHM shown in Fig. 9 which is 65 degree, is larger compared with the FWHM shown in Fig. 6 , which is 51 degree.
The pin 23 continues to slide in the curved groove 13 to a third position, which realizes a larger spacing between the geometrical centre of each lens 21 and the centre of emittance of its corresponding LED light source 11. Or in other words, a rotation angle θ2, larger than θ1 is formed. The light intensity distribution detected at the same position is a batwing distribution, which is shown in Fig. 11 . The FWHM shown in Fig. 12 is 82 degree.
For fixing in different positions, clamps or buckles may be provided.
The relative rotation between the optical assembly 2 and the LED light source assembly 1 could be realized by hand or by a motor. The rotation angle for a required light distribution is determined through another angle α. The angle α is formed by the line X' and the line X" (see Fig. 1 ). The line X' is a line passing through the centre of emittance of a LED light source 11 and the geometrical centre of its corresponding lens 21. The line X" also passes through the same centre of emittance and perpendicular to the plane of circle C1 and the plane of circle C2. When α is small enough, direct light intensity distribution could be generated. When α is larger, batwing light intensity distribution could be generated. In this way, whether a desired light distribution could be generated is directly determined by the angle α. However, in practical applications, the distance between the optical assembly 2 and the LED light source assembly 1 in a direction of central axis X is kept unchanged. As a result, it is easy to find out the relationship between the rotation angles and the patterns of light distribution. It is then possible to indirectly determine a light distribution through the rotation angle. Thus, another pattern of light distribution could be easily realized.
In the above example, the LED light sources 11 are evenly arranged in the first circle C1, and the lenses 21 are evenly arranged in the second circle C2, so that each lens 21 may be corresponding to a different LED light source 11. In other words, different rotation angles may realize the same light intensity distribution. For example, as shown in Fig 10 , ten LED light sources 11 are placed on the base plate 1', so the angle between the centres of emittance of two neighboring LED light sources is 36 degree. Thus, if the lenses assembly 2' is rotated over another 36° *m (m is 1, 2...) degree from the third position, the same batwing light distribution could be realized. This characteristic of the first embodiment makes the adjustment more flexible. For instance, if the rotation angle for generating a light distribution pattern is too small to be mechanically realized, other larger rotation angles may generate the same pattern. In addition, the relative rotation between the optical assembly 2 and the LED light source assembly 1 in one direction is enough; the rotation in both directions could be avoided. To realize the flexible adjustment, the curved groove 13 is a long curved groove.
Fig. 13 shows a perspective view of the LED light source assembly 1 of another modification of the first embodiment. Fig. 14 shows a top view of the LED light source assembly 1 from Fig. 13. In this modification, the curved groove 13 formed on the base plate 1' is replaced by two apertures 14 and 15. The pin 22 is in the central aperture. If the pin 23 is inserted into the aperture 14, a direct light intensity distribution is generated, and if the pin 23 is inserted into the aperture 15, a batwing light intensity distribution is generated. As mentioned before, different rotation angles may realize the same light distribution; therefore the apertures 14 and 15 may be formed in other positions on the base plate 1'. Optionally, more apertures could be formed on the base plate 1' to realize other patterns of light distribution.
Fig. 15 shows a perspective view of the illumination device 200 of a second embodiment according to the present invention. In this embodiment, the illumination device 200 comprises a first optical sub-assembly 2a and a second optical sub-assembly 2b. The two optical sub-assemblies are adjustable connected with the LED light source assembly 1.
It can be seen from Fig. 16 , which illustrates a perspective view of the LED light source assembly 1 of the second embodiment, the LED light source assembly 1 comprises a base plate 1' with two elongated recesses. The LED light sources 11, or more precisely, the centres of emittance of the LED light sources 11 are placed in two lines L4, L5 in the two elongated recesses, respectively. A cross section view of the LED light source assembly 1 from Fig. 16 is shown in Fig. 17 . The LED light sources 11 are mounted inwardly offset from the middle of the recesses. The dash lines in Fig. 17 indicate positions of the middle of the two recesses, respectively. The vertical distance between a dash line indicating the middle of a recess and a line (L4 or L5) of centres of emittance of the LED light sources arranged in the aforementioned recess is d/2.
Fig. 18 shows the two optical sub-assemblies 2a, 2b which can be inserted into the two elongated recesses from Fig. 16 . The two optical sub-assemblies 2a, 2b in Fig. 18 are both configured to have a strip shape. The first optical sub-assembly 2a has two long edges A and B. The second optical sub-assembly 2b has two long edges A' and B'. Geometrical centres of half of the lenses 21 are arranged in line L6 on the first optical sub-assembly 2a, and geometrical centres of the other half of the lenses 21 are arranged in line L7 on the second optical sub-assembly 2b. A cross section view of the two optical sub-assemblies from Fig. 18 is shown in Fig. 19 . It can be seen from Fig. 19 that the geometrical centres of lenses 21 are arranged outwardly offset from the middle of the optical sub-assemblies 2a, 2b, in other words, closer to edge A than to edge B or closer to edge A' than to edge B'. The long dash lines in Fig. 19 indicate the positions of the middle of the optical sub-assemblies, and point P and P' in Fig. 19 indicate the positions of the geometrical centres of the lenses 21. The distance from the point P or P' to a corresponding long dash line is d/2.
Fig.20 shows a top view of the illumination device 200 when the optical sub-assemblies are placed in a first orientation. Fig. 21 shows a cross section view of the illumination device from Fig. 20 . It can be seen from Fig. 21 that, the long edges A and A' are placed inwardly on the base plate 1', and the long edges B and B' are placed outwardly on the base plate 1'. Therefore, the two lines of lenses are arranged inwardly on the base plate 1', and the geometrical centre of each lens is aligned with the centre of emittance of its corresponding LED light source.
Fig. 22 is a polar plot of light intensity distribution on a plane parallel to the base plate 1' realized in this first orientation. Fig. 23 is a Cartesian plot of light intensity distribution on the same plane realized in this first orientation. It can be seen from Fig. 22 that direct light distribution is realized.
Fig. 24 shows a top view of the illumination device 200 when the optical sub-assemblies are placed in a second orientation. Fig. 25 shows a cross section view of the illumination device from Fig. 24 . It can be seen from Fig. 25 that, the long edges A and A' are placed outwardly on the base plate 1', and the long edges B and B' are placed inwardly on the base plate 1'. Therefore, the two lines of lenses are arranged outwardly on the base plate 1', and the geometrical centre of each lens is not aligned with the centre of emittance of its corresponding LED light source, but keeps a distance of d away.
Fig. 26 is a polar plot of light intensity distribution on a plane parallel to the base plate 1' realized in this second orientation. Fig. 27 is a Cartesian plot of light intensity distribution at the same position realized in the second orientation. It can be seen from Fig. 26 that batwing light distribution is realized.
The two optical sub-assemblies can also be inserted in to the elongated recesses in other orientations (not shown here), for example, the long edge A and B' are placed inwardly on the base plate 1', or the long edge A' and B are placed inwardly, to realize other patterns of light intensity distribution. In addition, the size of the recesses may be designed larger than the size of the optical sub-assemblies, so that, the sliding of the optical sub-assemblies in the recesses may also result in different patterns of light distribution.
Fig. 28 is an exploded view of another modification of the second embodiment. In this modification, the LED light sources 11, or more precisely, the centre of emittance of the LED light sources 11 are arranged in lines L4 and L5 on the base plate 1', but not in elongated recesses. Four mounting holes 16 are formed on the base plate 1'. Each of the two optical sub-assemblies 2a, 2b comprises two pins 26 extending away from the lower surface which is opposed to the surface arranged with lenses 21. The pins 26 can be inserted into the mounting holes 16 for mounting the two optical sub-assemblies together with the base plate 1'.
A cross section view of the modification from Fig. 28 is shown in Fig. 29 and Fig. 30 . The centre of emittance of LED light sources 11 are placed inwardly offset compared with the geometrical centers of the mounting holes. The geometrical centres of the lenses 21 are also arranged offset compared with the geometrical centers of their corresponding pins. So that, if the two optical sub-assemblies are mounted in a first orientation, the geometrical centre of each lens is aligned with the centre of emittance of its corresponding LED light source, and a direct light intensity distribution is realized. If the two optical sub-assemblies are mounted in a second orientation, the geometrical centres of the lenses are away from the centre of emittances of the LED light sources, respectively, and a batwing light intensity distribution is realized at the same position. Other light distribution patterns may also be realized through different mounting orientations or forming the holes 16 at different positions on the base plate 1'.
In a third embodiment of the illumination device shown in Fig. 31 , the illumination device 300 comprises a LED light source assembly 1 mounted with a plurality of LED light sources 11, and an optical assembly 2 placed above the LED light sources 11. The LED light sources 11 are divided into two groups, which are the inner group comprising four inner LED light sources arranged in a small circle C3, and the outer group comprising 10 LED light sources arranged in a large circle C4 surrounding the small circle C3. Fig. 32 shows a cross section view of the illumination device 300 from the Fig. 31 .
The two groups of LED light sources are controlled separately. For example, the inner four LED light sources are switched on while the outer ten LED light sources are switched off. A polar plot and a Cartesian plot of light intensity distribution realized in this situation are shown in Fig. 33 and Fig. 34 , respectively. From Fig. 33 , it can be seen that a direct light distribution is generated. In contrast, if the inner four LED light sources are switched off, and the outer ten LED light sources are switched on, a batwing light distribution is generated, which can be seen from the polar plot of light intensity distribution shown in Fig. 35 . A Cartesian plot of light intensity distribution is shown in Fig. 36 .
Nevertheless, there is no need to switch off the inner LED light sources or the outer LED light sources to realize the direct light distribution or the batwing light distribution. Certain luminous flux ratios may also realize the different patterns of light distribution. For example, if all the LED light sources are the same kind of LED light sources, then a direct light distribution can be realized when the inner LED light sources are operated to 70% of their maximum luminous flux, and the outer LED light sources are operated to 20% of their maximum luminous flux. A batwing light distribution can be realized when the inner LED light sources are operated to 20% of their maximum luminous flux, and the outer LED light sources are operated to 60% of their maximum luminous flux.
It is not necessary that all the LED light sources are the same LED light sources, certain ratios of the total luminous flux of the inner group and the outer group can also realize different patterns of light distribution.
It is also not necessary that the inner LED light sources are arranged in a small circle, and the outer LED light sources are arranged in a large circle as shown in Fig. 31 . The LED light sources can be arranged in other shapes. It is also not necessary that a group of LED light sources surrounds another group of LED light sources. The LED light sources may also be divided into more than two groups.
One LED light source comprised in the illumination device according to the present invention could comprise one LED or more than one LED. The LED could be all kinds of LED, such as CoB-LED, SMD-LED. They could also be other kinds of LED light sources according to the applications.
It can be noted that, the LED light source assembly 1 is not necessary to comprise a base plate 1' as described above, but could be any kind of LED light source assembly, which can be mounted with LED light sources. It can be also noted that, the optical assembly is not necessary to be a refractive optical assembly which comprises a lens or a plurality of lenses, but could also be a reflective optical assembly which comprises a reflector or a plurality of reflectors. It could even be a composite optical assembly with a refractive part and a reflective part.
The above is merely preferred embodiments of the present invention but not to limit the present invention. For the person skilled in the art, the present invention may have various alterations and changes. Any alterations, equivalent substitutions, improvements, within the spirit and principle of the present invention, should be covered in the protection scope of the present invention.

LIST OF REFERENCE SIGNS

Light source assembly: 1
Base plate: 1'
Optical assembly: 2
Lenses assembly: 2'
First optical sub-assembly: 2a
Second optical sub-assembly: 2b
LED light source: 11
Aperture: 12
Groove: 13
Aperture: 14
Aperture: 15
Mounting hole: 16
Lens: 21
Pin: 22
Pin: 23
Illumination device: 100
Illumination device: 200
Long edge: A
Long edge: A'
Long edge: B
Long edge: B'
First circle: C1
Second circle: C2
Small circle: C3
Large circle: C4
Line: L1
Line: L2
Line: L3
Line: L4
Line: L5
Line: L6
Line: L7
Point: P
Point: P'
Axis: X
Line: X'
Line: X'
Angle: α
Rotation angle: θ1
Rotation angle: θ2

Claims

An illumination device, comprising an LED light source assembly (1) including a plurality of LED light sources (11), and an optical assembly (2) including at least one optical element (21), connected to the LED light source assembly (1) for shaping the intensity distribution of the light emitted from the plurality of LED light sources (11), characterized in that a means is provided for generating at least a first light intensity distribution pattern and a second light intensity distribution pattern with the same LED light source assembly (1) and the same optical assembly (2).
The illumination device according to claim 1, wherein a distance between the LED light source assembly (1) and the optical assembly (2) along a principal axis of emittance of the light source assembly is constant while generating at least the first light intensity distribution pattern and the second light intensity distribution pattern.
The illumination device according to claim 1 or 2, wherein the optical assembly (2) comprises a plurality of optical elements (21), each of which is corresponding to one of the LED light sources (11).
The illumination device according to claim 3, wherein the means for generating at least the first light intensity distribution pattern and the second light intensity distribution pattern comprises a means of adjusting a distance between a principal axis of emittance of a light source (11) and the midpoint of the optical element corresponding to this light source (21).
The illumination device according to claim 3 or 4, wherein the LED light sources (11) are arranged in a first circle (C1).
The illumination device according to claim 5, wherein the optical elements (21) are arranged in a second circle (C2).
The illumination device according to claim 6, wherein the means of adjusting the relative position of a LED light source (11) and its corresponding optical element (21) in a direction perpendicular to the principal axis of emittance of the light source comprises a means of adjusting an angle (θ), which is formed by a first line (L1) passing through the center of C1 and the LED light source (11), and a second line (L2) which passes through the center of C1 and is parallel to a third line (L3) passing through the center of C2 and the optical element (21) corresponding to the light source.
The illumination device according to claim 3 or 4, wherein the LED light sources (11) are arranged on the LED light source assembly (1) in a fourth line (L4) and a fifth line (L5) parallel to the fourth line (L4).
The illumination device according to claim 8, wherein the optical assembly (2) comprises a first optical sub-assembly (2a) and a second optical sub-assembly (2b), and the optical elements (21) are arranged in a sixth line (L6) on the first optical sub-assembly (2a) and in a seventh line (L7) on the second optical sub-assembly (2b), respectively.
The illumination device according to claim 9, wherein the first optical sub-assembly (2a) and the second optical sub-assembly (2b) are adjustable connected with the LED light source assembly (1) in a first orientation, so that the fourth line (L4), the fifth line (L5), the sixth line (L6) and the seventh line (L7) are parallel to each other, and a first distance is formed between each of the principal axes of emittance of the light sources and the midpoint of the corresponding optical element, which results in the first light intensity distribution pattern.
The illumination device according to claim 9, wherein the first optical sub-assembly (2a) and the second optical sub-assembly (2b) are adjustable connected with the LED light source assembly (1) in a second orientation, so that the fourth line (L4), the fifth line (L5), the sixth line (L6) and the seventh line (L7) are parallel to each other, and a second distance larger than the first distance is formed between each of the principal axes of emittance of the light sources and the midpoint of the corresponding optical element, which results in the second light intensity distribution pattern.
The illumination device according to claim 1 or 2, wherein the means for generating at least the first light intensity distribution pattern and the second light intensity distribution pattern comprises a means of changing luminous flux of the plurality of LED light sources.
The illumination device according to claim 12, wherein the plurality of LED light sources (11) comprises at least a first group of LED light sources and a second group of LED light sources.
The illumination device according to claim 13, wherein the first light intensity distribution pattern and the second light intensity distribution pattern are realized by adjusting the luminous flux ratio between the first group of LED light sources and the second group of LED light sources.
The illumination device according to any one of the preceding claims, wherein the first light intensity distribution pattern is a direct light intensity distribution.
The illumination device according to any one of the preceding claims, wherein the second light intensity distribution pattern is a batwing light intensity distribution.
The illumination device according to any one of the preceding claims, wherein an optical element (21) comprises a lens or a reflector.
The illumination device according to any one of the preceding claims, wherein each LED light source (11) comprises one or more LEDs.