WO2015001174A1 - A method to accomplish a broadband, even and efficient led-light - Google Patents
A method to accomplish a broadband, even and efficient led-light Download PDFInfo
- Publication number
- WO2015001174A1 WO2015001174A1 PCT/FI2014/000015 FI2014000015W WO2015001174A1 WO 2015001174 A1 WO2015001174 A1 WO 2015001174A1 FI 2014000015 W FI2014000015 W FI 2014000015W WO 2015001174 A1 WO2015001174 A1 WO 2015001174A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- leds
- light
- spectrum
- method based
- light source
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/255—Details, e.g. use of specially adapted sources, lighting or optical systems
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
- G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
- G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
- G02B19/0061—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED
- G02B19/0066—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source the light source comprising a LED in the form of an LED array
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/20—Filters
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0005—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type
- G02B6/0006—Coupling light into the fibre
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/04—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings formed by bundles of fibres
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L25/00—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof
- H01L25/03—Assemblies consisting of a plurality of individual semiconductor or other solid state devices ; Multistep manufacturing processes thereof all the devices being of a type provided for in the same subgroup of groups H01L27/00 - H01L33/00, or in a single subclass of H10K, H10N, e.g. assemblies of rectifier diodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L33/00—Semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4298—Coupling light guides with opto-electronic elements coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
- H01L2924/0001—Technical content checked by a classifier
- H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
Definitions
- a method to accomplish a broadband, even and efficient LED-light is a method to accomplish a broadband, even and efficient LED-light.
- the object of this innovation is a technology used to produce broadband, even and efficient LED-light with a LED light source that comprises of several LEDs in which the spectrum is being shaped by filtering.
- Single LED light sources only produce light at a very narrow wave length range.
- the range is wide, but it typically includes two intensity peaks and a drop between them. Thus as such they do not come even close to being able to produce a Wide Band (WB) light equivalent to a halogen light source needed for example for demanding measurement purposes over the whole commonly used measurement range of 350 nm - 750 nm.
- WB Wide Band
- the commonly used solution is a broad band halogen lamp based on filament, where the desired part of the spectrum suited for the measurement in question is
- the required light output at the measuring wave length is higher than when measuring less absorbing or moderately scattering samples. This easily leads to high lamp outputs and low efficiency, when the majority of the light generated by the lamp has to be filtered out as unnecessary for the measurement.
- the advantage of light sources based on filament is a relatively even wide spectrum.
- the drawbacks are a fairly high power consumption and the heating factor as well as the especially limited life span.
- the measurement instrument When replacing a halogen lamp the measurement instrument usually needs to be recalibrated due to different output of light and also possible double work when unfinished and interrupted long term measurements have to be done over again.
- LED based lighting techniques are also being used in measurements today.
- the advantage of the LEDs is good energy efficiency, life span and controllable spectrum.
- the area creating light in a LED is usually relatively small in size, hence the light is optically easily controlled when using individual LEDs.
- the white LEDs have an uneven spectrum. Typically the white LED has a blue LED at the 430-450 run wave length and an earth metal or quantum point phosphorus, which is used to produce light for the 500-700 nm range.
- the problem with the white LEDs in regards to broadband measurements is a clear drop in intensity at the 470- 510 nm range and missing light Output at the 350-420 nm range.
- LEDs Another drawback of the LEDs is the variability of the intensity and wave length and/or distribution of the spectrum along with the current and temperature.
- a stable source of light is needed for different light based measurements for absorbance and scattering.
- the light source needs to be stable both regarding brightness and distribution of the spectrum, so that the measurement results will be comparable with each other.
- the stability and its means of control are important factors.
- Optical fibers are used in the instrument, where the structure of these fibers consists of bundles of thinner optical fibers.
- the quantities of optical fibers within the bundles vary, hence allowing more light to be collected from a weaker LED to achieve the desired spectrum.
- Light is collected from each needed LED to its own bundle of fiber with an optical arrangement as shown in the figures attached, which maximizes the transmission efficiency from each chosen LED to the top end of each fiber bundle.
- the fiber bundles of single LEDs are combined to a measurement optical fiber bundle ("main bundle of fiber"). To enable the use of this light in the real measurements, it needs to be homogeneous in order to provide reliable results. Due to this the individual optical fibers from each single LED bundle is then mixed together in the main bundle of fiber, in order to achieve this
- Fig. 1 shows the cut from the LED light source from figure 2 along the line A-A
- Fig. 2 shows the LED light source as seen from the side
- Fig. 3 shows the lens and filtering unit
- the chosen LEDs (101) have been attached to a temperature controlled circuit board (102).
- the temperature of the circuit board has been stabilized with for example a Peltier element (103) to standardize the operating temperature of the LEDs.
- the light of the LEDs is collected with the lenses (104) into bundles of optical fibers (150). It is noticeable that the distances of the lenses from both the LEDs and the tops of the fiber bundles have been set to collect the maximum amount of light by taking into account the effective focal length of the lenses at the wave length and the optical structure of the LEDs.
- the multichannel and adjustable power supply supplies the power set to the LEDs so that the spectrum of the light source reaches the desired distribution of brightness.
- the current can either be set based on a measurement done at production or a measurement feature can be integrated into the light source.
- the bundles of fibers (150) are combined by careful mixing into a single bundle (201), after which the light is mixed and filtered by using lenses (202) and filters (203) to create the final spectrum in the final optical fiber bundle (204).
- This invention also applies to an instrument where the light source described is used for measuring the absorption of a sample or for measuring the scattering caused by a sample.
Abstract
This invention pertains to a method for accomplishing broadband, even and efficient LED light using a LED light source comprising of several LEDs (101) and in which the spectrum is modified using filters. The combination of light from the LEDs together with the LEDs and filters (203) is used to create a desired distribution of spectrum. The light from the LEDs is being channeled with lenses (104, 202) to separate bundles of optical fiber (150, 201) which subsequently are joined together into one final bundle (204).
Description
A method to accomplish a broadband, even and efficient LED-light.
The object of this innovation is a technology used to produce broadband, even and efficient LED-light with a LED light source that comprises of several LEDs in which the spectrum is being shaped by filtering.
Single LED light sources only produce light at a very narrow wave length range. On the other hand, in the so called white LEDs which usually are based on utilizing phosphorizing substances, the range is wide, but it typically includes two intensity peaks and a drop between them. Thus as such they do not come even close to being able to produce a Wide Band (WB) light equivalent to a halogen light source needed for example for demanding measurement purposes over the whole commonly used measurement range of 350 nm - 750 nm.
Inter alia the following challenges occur when trying to create broadband WB light with LEDs for measurement purposes requiring a very narrow beam.of light:
As there is no spot-like light source (like for example filament) in the LEDs and since their relative intensity especially at certain wave lengths is small (compared with halogen light for example), it is very difficult to accumulate at even a moderate efficiency level and enough light to focus it on a small area like the top of an optical fiber.
To achieve the desired spectrum and level of intensity in the WB, the use of several LEDs complementing each other is required for the reasons mentioned above. To be able to get such light from many different light points homogeneously into one narrow beam for measurement technical purposes for example, is especially demanding.
The previously used solutions and their drawbacks
The commonly used solution is a broad band halogen lamp based on filament, where the desired part of the spectrum suited for the measurement in question is
defined with a filter. If measuring heavily absorbing solutions or a poorly scattering sample indirectly, the required light output at the measuring wave length is higher than when measuring less absorbing or moderately scattering samples. This easily leads to high lamp outputs and low efficiency, when the majority of the light generated by the lamp has to be filtered out as unnecessary for the measurement.
The advantage of light sources based on filament is a relatively even wide spectrum. The drawbacks are a fairly high power consumption and the heating factor as well as the especially limited life span. When replacing a halogen lamp the measurement instrument usually needs to be recalibrated due to different output of light and also possible double work when unfinished and interrupted long term measurements have to be done over again.
Several LED based lighting techniques are also being used in measurements today.
The advantage of the LEDs is good energy efficiency, life span and controllable spectrum. The area creating light in a LED is usually relatively small in size, hence the light is optically easily controlled when using individual LEDs.
The problem of monochromatic LEDs is the restricted availability of specific wave lengths, as LEDs are not being produced for all the wave lengths used in
measurements. Also, for some wave lengths there are no high efficient LEDs available at all and hence the output may be very restricted.
For some wave lengths only very inefficient LEDs are available, which means that it is of great importance to get their light as efficiently as possible to the measured object. On the other hand there are very powerful LEDs available for other wave lengths, which means that their proportion of the optical operating efficiency can be left smaller and be compensated with greater luminosity generated.
The white LEDs have an uneven spectrum. Typically the white LED has a blue LED at the 430-450 run wave length and an earth metal or quantum point phosphorus, which is used to produce light for the 500-700 nm range. The problem with the white LEDs in regards to broadband measurements is a clear drop in intensity at the 470- 510 nm range and missing light Output at the 350-420 nm range.
Another drawback of the LEDs is the variability of the intensity and wave length and/or distribution of the spectrum along with the current and temperature.
In case a very stable distribution of the spectrum and brightness is required (when aiming for example at 0.0001 OD measurement accuracy at longer time span), the temperature and control current of the LEDs need to be stabilized.
The intended use of the innovation
A stable source of light is needed for different light based measurements for absorbance and scattering. The light source needs to be stable both regarding brightness and distribution of the spectrum, so that the measurement results will be comparable with each other. Especially in long term automatic measurements the stability and its means of control are important factors.
The method on which this innovation is based on is characterized by the joint effect of the light coming from the LEDs and the effect of the filter/s together create the desired distribution of the spectrum. Different forms of implementing this innovation have been presented in the non-independent patent requirements further below.
The solution offered by the innovation
Optical fibers are used in the instrument, where the structure of these fibers consists of bundles of thinner optical fibers. The quantities of optical fibers within the bundles vary, hence allowing more light to be collected from a weaker LED to achieve the desired spectrum.
Light is collected from each needed LED to its own bundle of fiber with an optical arrangement as shown in the figures attached, which maximizes the transmission efficiency from each chosen LED to the top end of each fiber
bundle. By choosing the appropriate types of LEDs and the correct amount of them, it is possible to create light with high and even intensity in the 350 nm - 750 nm range that as such can replace i.a. a halogen light source in this kind of applications.
The fiber bundles of single LEDs are combined to a measurement optical fiber bundle ("main bundle of fiber"). To enable the use of this light in the real measurements, it needs to be homogeneous in order to provide reliable results. Due to this the individual optical fibers from each single LED bundle is then mixed together in the main bundle of fiber, in order to achieve this
requirement of homogenization.
The advantages of this innovation
Significantly longer life span than with the traditional halogen light sources.
Creation of desired shaped spectrum with the LEDs.
Very stable distribution of the spectrum.
Very stable brightness.
Possibility of utilizing efficiently LEDs of very different power output.
This invention is here explained by examples with references to the attached drawings where
Fig. 1 shows the cut from the LED light source from figure 2 along the line A-A
Fig. 2 shows the LED light source as seen from the side
Fig. 3 shows the lens and filtering unit
The chosen LEDs (101) have been attached to a temperature controlled circuit board (102). The temperature of the circuit board has been stabilized with for example a Peltier element (103) to standardize the operating temperature of the LEDs. The light of the LEDs is collected with the lenses (104) into bundles of optical fibers (150). It is noticeable that the distances of the lenses from both the LEDs and the tops of the fiber bundles have been set to collect the maximum amount of light by taking into account the effective focal length of the lenses at the wave length and the optical structure of the LEDs.
The multichannel and adjustable power supply supplies the power set to the LEDs so that the spectrum of the light source reaches the desired distribution of brightness. The current can either be set based on a measurement done at production or a measurement feature can be integrated into the light source.
The bundles of fibers (150) are combined by careful mixing into a single bundle (201), after which the light is mixed and filtered by using lenses (202) and filters (203) to create the final spectrum in the final optical fiber bundle (204). By
appropriately adjusting the distances of the lenses it is possible to avoid the formation of an image of any single fiber in the final fiber, which otherwise could lead to an uneven distribution of light.
This invention also applies to an instrument where the light source described is used for measuring the absorption of a sample or for measuring the scattering caused by a sample.
Claims
1. Method to accomplish a broadband and even, efficient LED light using a LED light source comprising of several LEDs (101) in which the spectrum is modified by filtering and in which a desired distribution of the spectrum is created by mixing the light produced by the several LEDs and filter(s), characterized by the light of the LEDs being channeled with lenses (104, 202) into separate bundles of optical fibers (150, 201), which subsequently are joined together into one final bundle (204).
2. Method based on Claim 1, characterized by adjusting electrically the relative intensity of the LEDs in order to produce a desired distribution of the spectrum.
3. Method based on Claim 1 or Claim 2, characterized by stabilizing the temperature of the LEDs eg. by means of a Peltier-element (103) in order to stabilize the spectrum and the intensity of the light.
4. Method based on any of the above Claims, characterized by stabilizing the temperature of the LEDs (101) at a temperature above the ambient, thus utilizing the heat produced by the LEDs and operating the Peltier-element (103) in a more efficient temperature range.
5. Method based on any of the above Claims, characterized by synchronized chopping of the light from the LEDs (101).
6. Method based on any of the above Claims, characterized by chopping the light of individual LEDs at different frequencies, thereby making it possible to distinguish between the light produced by individual LEDs during the measurement.
7. An instrument utilizing optical fibers and implementing the methods described in any of the above Claims, characterized by the structure of the optical fiber bundle comprising thinner bundles of optical fibers (150) with varying numbers of fibers thus enabling the collection of more light from weaker LEDs and thus creating the desired distribution of spectrum.
8. An instrument based on Claim 7, characterized by the light source being used to measure the absorption of a sample.
9. An instrument based on Claim 7, characterized by the light source being used to measure the scattering of the sample.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI20130195 | 2013-07-03 | ||
| FI20130195A FI20130195L (en) | 2013-07-03 | 2013-07-03 | A method to achieve broadband and uniform efficient LED light |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| WO2015001174A1 true WO2015001174A1 (en) | 2015-01-08 |
Family
ID=52143158
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/FI2014/000015 WO2015001174A1 (en) | 2013-07-03 | 2014-07-02 | A method to accomplish a broadband, even and efficient led-light |
Country Status (2)
| Country | Link |
|---|---|
| FI (1) | FI20130195L (en) |
| WO (1) | WO2015001174A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0522548A1 (en) * | 1991-07-10 | 1993-01-13 | Eaton Corporation | Color sensor employing optical fiber bundles with varied diameters |
| US20030058450A1 (en) * | 2001-09-25 | 2003-03-27 | Mosley R. Matthew | Instrument and method for testing fluid characteristics |
| US20030147254A1 (en) * | 2001-12-04 | 2003-08-07 | Kenji Yoneda | Light radiation device, light source device, light radiation unit, and light connection mechanism |
| US20050047172A1 (en) * | 2003-08-28 | 2005-03-03 | Ulrich Sander | Light-emitting diode illumination system for an optical observation device, in particular a stereomicroscope or stereo surgical microscope |
| US20070265532A1 (en) * | 2002-04-04 | 2007-11-15 | Maynard John D | Determination of a Measure of a Glycation End-Product or Disease State Using a Flexible Probe to Determine Tissue Fluorescence of Various Sites |
| CN102778439A (en) * | 2012-06-28 | 2012-11-14 | 中国科学院合肥物质科学研究院 | Multiple-light-emitting-diode (LED) combined wideband light source device applied to difference absorption spectrum system |
-
2013
- 2013-07-03 FI FI20130195A patent/FI20130195L/en not_active Application Discontinuation
-
2014
- 2014-07-02 WO PCT/FI2014/000015 patent/WO2015001174A1/en active Application Filing
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0522548A1 (en) * | 1991-07-10 | 1993-01-13 | Eaton Corporation | Color sensor employing optical fiber bundles with varied diameters |
| US20030058450A1 (en) * | 2001-09-25 | 2003-03-27 | Mosley R. Matthew | Instrument and method for testing fluid characteristics |
| US20030147254A1 (en) * | 2001-12-04 | 2003-08-07 | Kenji Yoneda | Light radiation device, light source device, light radiation unit, and light connection mechanism |
| US20070265532A1 (en) * | 2002-04-04 | 2007-11-15 | Maynard John D | Determination of a Measure of a Glycation End-Product or Disease State Using a Flexible Probe to Determine Tissue Fluorescence of Various Sites |
| US20050047172A1 (en) * | 2003-08-28 | 2005-03-03 | Ulrich Sander | Light-emitting diode illumination system for an optical observation device, in particular a stereomicroscope or stereo surgical microscope |
| CN102778439A (en) * | 2012-06-28 | 2012-11-14 | 中国科学院合肥物质科学研究院 | Multiple-light-emitting-diode (LED) combined wideband light source device applied to difference absorption spectrum system |
Also Published As
| Publication number | Publication date |
|---|---|
| FI20130195L (en) | 2015-01-04 |
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