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Title:
LED ILLUMINATING DEVICE WITH MULTI-SEGMENT DIRECTIONAL OPTICS
Document Type and Number:
WIPO Patent Application WO/2016/171631
Kind Code:
A1
Abstract:
The object of the invention is a LED illuminating device (1) with multi-segment directional optics (2) that represents a concept of an illuminating device that considerably increases light quality in LED illuminating devices and reaches better efficiency compared to existing methods of light distribution. The solution also results in a low operating temperature of illuminating devices, in a simultaneous increase in efficiency of LEDs, and in an extended lifespan of the illuminating device or its components. A LED illuminating device with multi-segment directional optics of the invention eliminates drawbacks of known solutions by a LED lamp, in which the light of LEDs reflects from multi-segment optics of the illuminating device, which is made from a high-tech reflective material, wherein the multi-segment optics allows for any pre-defined and planned light distribution. Each segment can illuminate an entire or desired area with soft uniform light, wherein the number of segments is in a range from three to fifteen.

Inventors:
PEČAN, Tomaž (Žeje 2, 1000 Ljubljana, SI)
Application Number:
SI2016/000013
Publication Date:
October 27, 2016
Filing Date:
April 18, 2016
Export Citation:
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Assignee:
PEČAN, Tomaž (Žeje 2, 1000 Ljubljana, SI)
VRTAČNIK, Hine, Alex (Vinterca 53, 1000 Ljubljana, SI)
International Classes:
F21V7/04; F21V7/00; F21Y115/10
Domestic Patent References:
WO2000071930A12000-11-30
Foreign References:
US20140226328A12014-08-14
US20120182713A12012-07-19
US20100157607A12010-06-24
EP0942225A21999-09-15
Attorney, Agent or Firm:
PIPAN, Marjan (Kotnikova 5, 1000 Ljubljana, SI)
Download PDF:
Claims:
CLAIMS

1. A LED illuminating device with multi-segment directional optics

characterized in that

a printed circuit board (3) with LEDs is arranged at an angle in the area of multi-segment optics (2), wherein the light reflects from the multi- segment optics (2) in a way that each segment individually illuminates an entire or desired illuminating area with soft uniform light.

2. The LED illuminating device according to claim 1

characterized in that

the multi-segment optics (2) has a minimum of three and a maximum of fifteen segments.

3. The LED illuminating device according to claims 1 and 2

characterized in that

the shape of each segment is calculated in a way that each individual segment provides for individual light distribution and covers a predetermined illuminating area.

4. The LED illuminating device according to claims 2 and 3

characterized in that

the multi-segment optics (2) is made from a high-tech reflective material.

5. The LED illuminating device according to any of preceding claims characterized in that

the arrangement of LEDs on the printed circuit (3) corresponds to a step in the range from 1.2 to 10-times the output area of the LEDs.

6. The LED illuminating device according to any of preceding claims

characterized in that

the leg(s) of the aluminium profile (5), to which the printed circuit board (3) is fastened, lies/lie at an angle that ranges from -40 to 40° relative to the basic illumination direction depending on desired light distribution and construction of the illuminating device.

7. The LED illuminating device according to any of preceding claims

characterized in that

the printed circuit board (3) with LEDs is fastened to a combined aluminium holder (5) that simultaneously discharges heat from the LEDs and a supply circuit (4) to an external housing (1), wherein the power supply can also be arranged outside of the housing (1) of the illuminating device.

8. The LED illuminating device according to any of preceding claims

characterized in that

it comprises one or several light fields, wherein the light field can be in the shape of a square or a circle.

Description:
LED ILLUMINATING DEVICE WITH MULTI-SEGMENT DIRECTIONAL

OPTICS

The object of the invention is a LED illuminating device with multi- segment directional optics that represents a concept of an illuminating device that considerably increases light quality in LED illuminating devices and reaches better efficiency compared to existing methods of light distribution. The solution also results in a low operating temperature of illuminating devices, in a simultaneous increase in efficiency of LEDs, and in an extended lifespan of the illuminating device or its components. The invention belongs to class F 21V 7/04 of the International Patent Classification.

Technical problems that are solved by the present invention are predominantly elimination of an undesired zebra effect of shadows (shown in Figure 1), elimination of spot glare of LEDs, and elimination of high operating temperature of illuminating devices. When LEDs are used in practice, huge problems relating to degradation of light quality and to worsening of working and living conditions appear. Since a LED is a spot light source on a small surface with normally high light intensity, undesired spot glare and zebra effect occur (Figure 1).

Existing solutions solve or rather partly solve a part of problems relating to LED illuminating devices. Predominantly only light distribution and heat discharge are solved. In fact, the zebra effect of shadows and spot light distribution typical of LED illuminating devices remain. The illuminating devices, in which the latter problem is solved, consequently have a considerably worse optical efficiency. This efficiency represents a ratio between emitted light of LEDs and total emitted light of an illuminating device that can be reduced by up to 30%.

Most frequent practical applications of LEDs:

Cob module illuminating device. Because of one multi-chip module a glare level is highest. A solution of this type has poor light distribution. Due to a high power/surface ratio of each individual module, temperature discharge problems occur, which results in a high operating temperature of a COB LED module.

LED illuminating device with a matrix of LEDs. Individual LEDs cause a high level of spot glare, the undesired zebra effect and poor light distribution that is caused by a radiation angle of LEDs. A problem of light distribution is normally solved by lenses that in turn additionally reduce efficiency of the illuminating device due to losses on lenses and range from 8 to 25%.

LED illuminating device in the form of a fluorescent tube. Light distribution is limited only to a radiation angle of LEDs. If a front diffusion glass is used, the zebra effect is reduced or even eliminated. Efficiency is reduced by 15 to 20%. As the LEDs are closed within a tube, heat discharge is not possible and this reduces the lifespan of LEDs.

The invention described in KR20110088377 partly eliminates zebra effect problems. A problem is poorer light distribution and lower optical efficiency, because a concept of this type does not provide for single reflections unlike the present invention. The LEDs get overheated because the design does not allow optimal discharge of heat from the LEDs.

A LED illuminating device with multi-segment directional optics of the invention eliminates drawbacks of known solutions by a LED lamp, in which the light of LEDs reflects from multi-segment optics of the illuminating device, which is made from a high-tech reflective material, wherein the multi-segment optics allow for any pre-defined and planned light distribution. Each segment can illuminate an entire or desired area with soft uniform light, wherein the number of segments is in a range from three to fifteen.

The invention will be explained in more detail by way of an embodiment and the enclosed drawings, in which:

Figure 1 shows an undesired zebra effect of shadows;

Figure 2 shows a light area of the illuminating device of the invention;

Figure 3 shows optics light distribution;

Figure 4 shows arrangement of LEDs on a printed circuit board;

Figure 5 schematically shows an angle of arrangement of LEDs;

Figure 6 shows a cross-section of an assembled illuminating device.

Figure 1 schematically shows a zebra effect of shadows. This is an effect that occurs when a matrix or field of a large number of LEDs is used. An example of a LED field is for instance 15x8, 80x3, line 100x1 , etc. For illustration purposes, an object illuminated by a field of LEDs is taken. An object that is present in front of a LED casts a shadow behind itself. The shadow gets multiplied by the number of LEDs and this means an entire field of shadows behind the object that corresponds to the matrix arrangement. Shadows of this type are very disturbing in practice and reduce realistic perception of a space.

The illuminating device of the invention has LEDs arranged on a printed circuit board 3 that is fastened on an external portion of one or both legs of an aluminium profile 5. A power supply 4 of the illuminating device is arranged within the aluminium profile 5. In case of extremely high temperature requirements the power supply 4 may also be arranged outside of a housing 1 of the illuminating device. LEDs are arranged in one row, wherein a step (S) between LEDs amounts to a value from 1.2 of the output area of a LED (I) to 10-times the output area. Adequate distance is defined on the basis of power of LEDs and required light uniformity. The leg(s) of the aluminium profile 5, to which the printed circuit board 3 is fastened, lies/lie at an adequate angle that ranges from -40 to 40° relative to the basic illumination direction depending on desired light distribution and construction of the illuminating device.

A predominant part of the luminous flux of LEDs reflects with a single reflection from a multi-segment optics 2 to a desired spot of illumination, which is shown in Figure 3. A direct/indirect light ratio must be in favour of the indirect light.

It depends on the angle of the printed circuit board 3 with LEDs or the printed circuit boards 3 relative to an illuminated area 5. The luminous flux reflects from each segment of the segment optics 2 at an angle corresponding to a proportional incident angle of the luminous flux to a predefined and calculated spot of illumination, wherein this spot can cover the entire spot of illumination or only a part thereof. The optimized multi- segment optics 2 makes it possible to reach a broader illuminating area with desired light distribution. A needed number of segments is in the range from three to fifteen. Each individual segment provides for individual light distribution with its shape (wide beam, narrow beam etc.) and covers a pre-determined illuminating area. The shape of each segment is precisely calculated in compliance with light distribution requirements, the calculation being performed by dedicated software. The segments within an illuminating device can be of various types (dispersing, directional) and an optimal result can be achieved accordingly.

The aluminium profile 5 is fastened to the external housing 1 serving as a main heat sink. The heat sink can be flat in case of lower powers but can be corrugated on the external side at higher powers. The heat which is released while the LEDs are operative is transferred through the printed circuit board 3 to the aluminium profile 5 and therethrough to the external housing 1. Part of the heat is also taken over by the segment optics 2 which exploits convection to transfer the heat to the housing and via infrared radiation outside from the illuminating device of the invention. The heat which occurs on the power supply 4 due to losses gets transferred via aluminium profile 5 to the external housing 1.

The LED illuminating device of the invention may be realized as a single-optics variant with a single printed circuit board 3 with LEDs or with several optics with several printed circuit boards 3 with LEDs. The embodiment may be in a square or circular variant. Due to its adequate optics design the LED illuminating device with multi-segment directional optics has a maximized illuminating area as shown in Figure 2. When reflective segment optics 2 made from a hightech material with an adequate level of diffusion is used, minimum losses in reflection are achieved (approx. 3%), which is a very efficient method in comparison with conventional lenses for LEDs (8-25%). Since the LEDs in this method are not covered with conventional lenses such as PPMA, PC... , the temperature around the LED is lower and this still additionally protects the LEDs from early aging.

The technical solution to optical light distribution of the proposed invention provides for a quality soft light directed to a desired spot, wherein the illuminating device has an above-average optical efficiency. Large illuminating area with very good optical efficiency and consequently low UGR factor is very user friendly. If a person (blue-collar worker, driver, pedestrian, sports centre participant...) happens to look at a lamp, the latter does not glare him for a short period of time and when the person looks away, no light imprint remains on his retina like in more harmful mono/multi-point sources and he can continue his activity without any danger. Adequate structure makes also the operating temperature of LEDs and the power supply low.