EP2381244A1 - Light source - Google Patents

Light source Download PDF

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Publication number
EP2381244A1
EP2381244A1 EP10160812A EP10160812A EP2381244A1 EP 2381244 A1 EP2381244 A1 EP 2381244A1 EP 10160812 A EP10160812 A EP 10160812A EP 10160812 A EP10160812 A EP 10160812A EP 2381244 A1 EP2381244 A1 EP 2381244A1
Authority
EP
European Patent Office
Prior art keywords
light source
light
illuminant
laser
red
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP10160812A
Other languages
German (de)
French (fr)
Inventor
designation of the inventor has not yet been filed The
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Philips Intellectual Property and Standards GmbH
Koninklijke Philips NV
Original Assignee
Philips Intellectual Property and Standards GmbH
Koninklijke Philips Electronics NV
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Philips Intellectual Property and Standards GmbH, Koninklijke Philips Electronics NV filed Critical Philips Intellectual Property and Standards GmbH
Priority to EP10160812A priority Critical patent/EP2381244A1/en
Priority to PCT/IB2011/051694 priority patent/WO2011132146A1/en
Publication of EP2381244A1 publication Critical patent/EP2381244A1/en
Ceased legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21K—NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
    • F21K9/00—Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/10—Light-emitting diodes [LED]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21Y—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED
    • F21Y2115/00—Light-generating elements of semiconductor light sources
    • F21Y2115/30—Semiconductor lasers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J61/00—Gas-discharge or vapour-discharge lamps
    • H01J61/02—Details
    • H01J61/12—Selection of substances for gas fillings; Specified operating pressure or temperature
    • H01J61/18—Selection of substances for gas fillings; Specified operating pressure or temperature having a metallic vapour as the principal constituent

Definitions

  • the invention relates to a light source.
  • the invention relates to a lamp including the light source.
  • the invention targets in improving the ability to realize details. It is an object of the invention to provide a light source addressing said target.
  • a light source comprises an illuminant emitting radiation with wavelengths of 500nm to 550nm and/or of 585nm to 640nm.
  • the illuminant emits radiation with wavelength of 515nm to 535nm and/or of 600nm to 620nm. That is, the illuminant may emit radiation with wavelength of about 525nm, which may be between 523nm and 527nm, and/or of about 610nm, which may be between 608nm and 612nm.
  • wavelengths in the green spectrum of visible light 500nm to 550nm
  • wavelengths in the red spectrum of visible light 585nm to 640nm
  • the contrast or at least the comfort in utilizing such a light source may also be enhanced by a combination of the mentioned spectra.
  • an illuminant emitting radiation with wavelengths of the green spectrum and of the red spectrum, simultaneously, will provide for a better contrast.
  • the light source comprises a light emitting diode (LED).
  • a light source may comprise a plurality of LEDs to have a better brightness.
  • a number of red LEDs may be combined with a number of green LEDs in one light source or lamp.
  • the light emitting diode may include an element out of the group consisting of an AlInGaP-LED and an InGaN-LED.
  • the light source comprises a discharge tube.
  • the emitting medium it is possible to emit radiation with a spectrum of green and/or red light.
  • Green light wavelengths may be achieved by the use of Chrome or Copper.
  • Red light wavelengths may be achieved by the use of Lithium or Calcium.
  • the LEDs or discharge light source may be provided with selective filters to narrow down the emission spectrum of the light source.
  • the light source comprises a laser.
  • a laser may comprise a diode pumped Nd-YAG element which frequency is subsequently doubled and/or a red diode laser.
  • the light sources in accordance with the invention may be utilized as a lamp for elder people, as a lamp for a microscope, as street lighting or as automobile front light, wherein the lamp includes a light source as described above.
  • a light source according to the invention is capable of enhancing the contrast of something visible
  • the processing of light by an eye will be described in a first step.
  • Fig. 1 is a schematically illustration of light processing in an eye.
  • the retina of an eye comprises neurons of the ganglion 10, cross-linked neurons 20, cone-cells 30, and rod-cells 40.
  • An incidence of light 100 onto the retina will trigger an activity of the neurons and cells so as to send pulses to the visual nerve by the nervus opticus 50.
  • a retina comprises three receptors for color vision, i.e. cones which are sensitive for red light, cones which are sensitive for green light, and cones which are sensitive for blue light.
  • red, green and blue are substantially relevant for the brightness V( ⁇ ).
  • red-green vision r( ⁇ )-g( ⁇ ) is relevant. This may be gathered from the fact that the most red and green cones can be found in the area of the yellow spot or macula of the retina.
  • the absorption spectra in fig.3 show peaks of the respective cones in the blue B, green G and red R spectra.
  • the dotted line indicates the absorption of the rods which are relevant for the black-and-white vision.
  • FIG. 4 Another illustration of the different sensitivity of the different cones, may be seen in fig. 4 , showing peaks of a green-red-cell (G-R), a red-green-cell (R-G), and of a blue-yellow-cell (B-Y) and a yellow-blue-cell (Y-B).
  • G-R green-red-cell
  • R-G red-green-cell
  • B-Y blue-yellow-cell
  • Y-B yellow-blue-cell
  • lamps having an illuminant emitting light within the ranges stated above.
  • a lamp comprises a laser 200 which usually provides for a selective and small band emission.
  • a laser emitting a green beam 210 may be realized on the basis of a diode pumped NdY-AG laser with subsequent frequency doubling. Such a laser may have a wavelength of 532nm of its radiation.
  • a lamp 300 comprises two different LEDs with emission wavelengths of about 525nm (310) and 610nm (320), respectively.
  • LEDs on the basis of AlInGaP- and InGaN-LEDs have such emission wavelength.
  • a lamp 400 comprises a plurality of discharge light sources, which have collectively emission wavelengths of about 525nm and about 610nm.
  • discharge light sources with at least one element out of the following group are usable.
  • Thallium (Tl) 535,1nm Chromium (Cr) 520,5nm and 520,8nm
  • a discharge light source may comprise mercury and/or a noble gas as start gas or buffer gas.
  • the above mentioned elements may also be provided as compound like halogenide, oxide and chalkogenide.
  • a lamp comprises a combination of at least one type of LEDs and at least one discharge light source.

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optics & Photonics (AREA)
  • General Engineering & Computer Science (AREA)
  • Led Device Packages (AREA)
  • Non-Portable Lighting Devices Or Systems Thereof (AREA)

Abstract

The application targets in improving the ability to realize details. In general, a light source according to the invention comprises an illuminant emitting radiation with wavelengths of 500nm to 550nm and/or of 585nm to 640nm. The light source may comprise a light emitting diode (LED), a discharge tube and/or a laser. Such a light source may be utilized in a lamp for elder people, in a lamp for a microscope, in street lighting or in automobile front light.

Description

    FIELD OF THE INVENTION
  • The invention relates to a light source. In particular, the invention relates to a lamp including the light source.
    • BACKGROUND OF THE INVENTION
  • In some applications it is important to recognize things or aspects of things. The ability of realizing details may depend on the possibility to see something with a good contrast, for example, if elder people want to read something, if scientists want to differentiate structures with a microscope, or if movable objects on a street have to be recognized to avoid an accident.
    • SUMMARY OF THE INVENTION
  • The invention targets in improving the ability to realize details. It is an object of the invention to provide a light source addressing said target.
  • This is achieved by the subject matter of each of the independent claims. Further embodiments of the invention are described in the dependent claims.
  • In general, a light source according to the invention comprises an illuminant emitting radiation with wavelengths of 500nm to 550nm and/or of 585nm to 640nm. Preferably, the illuminant emits radiation with wavelength of 515nm to 535nm and/or of 600nm to 620nm. That is, the illuminant may emit radiation with wavelength of about 525nm, which may be between 523nm and 527nm, and/or of about 610nm, which may be between 608nm and 612nm.
  • It is noted that either the wavelengths in the green spectrum of visible light (500nm to 550nm) or the wavelengths in the red spectrum of visible light (585nm to 640nm) are suitable to achieve the intended effect of providing a better contrast.
  • The contrast or at least the comfort in utilizing such a light source, may also be enhanced by a combination of the mentioned spectra. In other words, an illuminant emitting radiation with wavelengths of the green spectrum and of the red spectrum, simultaneously, will provide for a better contrast.
  • According to a first embodiment of the invention, the light source comprises a light emitting diode (LED). It will be understood, that a light source may comprise a plurality of LEDs to have a better brightness. For a light source emitting green light together with red light, a number of red LEDs may be combined with a number of green LEDs in one light source or lamp.
  • For example, the light emitting diode may include an element out of the group consisting of an AlInGaP-LED and an InGaN-LED.
  • According to a second embodiment of the invention, the light source comprises a discharge tube. With an appropriate choice of the emitting medium, it is possible to emit radiation with a spectrum of green and/or red light. Green light wavelengths may be achieved by the use of Chrome or Copper. Red light wavelengths may be achieved by the use of Lithium or Calcium.
  • Furthermore, the LEDs or discharge light source may be provided with selective filters to narrow down the emission spectrum of the light source.
  • According to a third embodiment of the invention, the light source comprises a laser. Such a laser may comprise a diode pumped Nd-YAG element which frequency is subsequently doubled and/or a red diode laser.
  • The light sources in accordance with the invention may be utilized as a lamp for elder people, as a lamp for a microscope, as street lighting or as automobile front light, wherein the lamp includes a light source as described above.
  • It has to be noted that a person skilled in the art will gather from the above and the following description that, unless other notified, in addition to any combination of features belonging to one embodiment also any combination between features relating to another embodiment is considered to be disclosed with this application.
  • The aspects defined above and further aspects, features and advantages of the present invention can also be derived from the examples of the embodiments to be described herein after and are explained with reference to examples of embodiments also shown in the figures, but to which the invention is not limited.
    • BRIEF DESCRIPTION OF THE DRAWINGS
    • Fig. 1 is a schematically illustration of light processing in an eye.
    • Fig. 2 illustrates the processing of different colors.
    • Fig. 3 shows an absorption spectrum of blue, red and green cones.
    • Fig. 4 is a diagram showing a spectral sensitivity of green/red-cells and of blue/yellow-cells.
    • Fig. 5 shows an exemplary embodiment of a laser-based lamp.
    • Fig. 6 shows an exemplary embodiment of a LED-based lamp.
    • Fig. 7 shows an exemplary embodiment of a discharge-based lamp.
    DETAILED DESCRIPTION OF EMBODIMENTS
  • As an explanation of why a light source according to the invention is capable of enhancing the contrast of something visible, the processing of light by an eye will be described in a first step.
  • Fig. 1 is a schematically illustration of light processing in an eye. The retina of an eye comprises neurons of the ganglion 10, cross-linked neurons 20, cone-cells 30, and rod-cells 40. An incidence of light 100 onto the retina will trigger an activity of the neurons and cells so as to send pulses to the visual nerve by the nervus opticus 50.
  • A retina comprises three receptors for color vision, i.e. cones which are sensitive for red light, cones which are sensitive for green light, and cones which are sensitive for blue light.
  • An important aspect is that the information of these three different receptors will be processed by the retina, immediately, for example by the cross-linked neurons 20.
  • From fig. 2, it may be gathered that the information of the red, green and blue cones (R, G, B) are processed such that firstly a difference of red and green is generated. Secondly a difference of yellow and blue is generated, wherein yellow is an addition of red and green. Thirdly an addition of red, green and blue is generated.
  • It is noted that the result of the addition of red, green and blue is substantially relevant for the brightness V(λ). For especially visualization with a high contrast of small structures, the red-green vision r(λ)-g(λ) is relevant. This may be gathered from the fact that the most red and green cones can be found in the area of the yellow spot or macula of the retina.
  • Consequently, the absorption spectra in fig.3 show peaks of the respective cones in the blue B, green G and red R spectra. The dotted line indicates the absorption of the rods which are relevant for the black-and-white vision.
  • Another illustration of the different sensitivity of the different cones, may be seen in fig. 4, showing peaks of a green-red-cell (G-R), a red-green-cell (R-G), and of a blue-yellow-cell (B-Y) and a yellow-blue-cell (Y-B).
  • According to fig.4, there exists a cell which is especially sensitive for radiation with 525nm, and further a cell which is especially sensitive for radiation with 610nm.
  • In the following, exemplary embodiments of lamps are described, having an illuminant emitting light within the ranges stated above.
  • According to a first embodiment, shown in fig. 5, a lamp comprises a laser 200 which usually provides for a selective and small band emission. A laser emitting a green beam 210 may be realized on the basis of a diode pumped NdY-AG laser with subsequent frequency doubling. Such a laser may have a wavelength of 532nm of its radiation.
  • According to a second embodiment, shown in fig. 6, a lamp 300 comprises two different LEDs with emission wavelengths of about 525nm (310) and 610nm (320), respectively. For example, LEDs on the basis of AlInGaP- and InGaN-LEDs have such emission wavelength.
  • According to a third embodiment, a lamp 400 comprises a plurality of discharge light sources, which have collectively emission wavelengths of about 525nm and about 610nm. For example, discharge light sources with at least one element out of the following group are usable.
    Sodium (Na) 589,0nm and 589,5nm
    Barium (Ba) 553,5nm
    Magnesium (Mg) 518,4nm, 517,3nm and 516,7nm
    Thallium (Tl) 535,1nm
    Chromium (Cr) 520,5nm and 520,8nm
    Lithium (Li) 610,4nm and 670,0nm
    Copper (Cu) 521,8nm, 522,0nm, 515,3nm and 510,5nm
    Mercury (Hg) 546,1nm
    Calcium (Ca) 610,2nm, 612,2nm and 616,2nm
  • Additionally, a discharge light source may comprise mercury and/or a noble gas as start gas or buffer gas. The above mentioned elements may also be provided as compound like halogenide, oxide and chalkogenide.
  • According to a fourth embodiment, a lamp comprises a combination of at least one type of LEDs and at least one discharge light source.
  • While the invention has been illustrated and described in detail in the drawings and afore-going description, such illustrations and descriptions are to be considered illustrative or exemplary and not restrictive, the invention is not limited to the disclosed embodiments.
  • Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure and the appended claims. In the claims, the word 'comprising' does not exclude other elements, and the indefinite article 'a' or 'an' does not exclude a plurality.
  • The mere fact that certain measures are recited and mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope.
    • LIST OF REFERENCE SIGNS:
    • 10
    neurons of the ganglion
    20
    cross-linked neurons
    30
    cone-cells
    40
    rod-cells
    50
    nervus opticus
    100
    light
    200
    laser
    210
    laser beam
    300
    LED lamp
    310
    first LED
    320
    second LED
    400
    discharge lamp
    R
    red
    G
    green
    B
    blue
    Y
    yellow

Claims (12)

  1. A light source, comprising:
    an illuminant emitting light with wavelengths of 500nm to 550nm and/or of 585nm to 640nm.
  2. The light source of claim 1,
    wherein the illuminant emits light with wavelength of 515nm to 535nm and/or of 600nm to 620nm.
  3. The light source of claim 1,
    wherein the illuminant emits light with wavelength of 523nm to 527nm and/or of 608nm to 612nm.
  4. The light source of claim 1,
    wherein the illuminant comprises a light emitting diode (LED)(310, 320).
  5. The light source of claim 1 or 4,
    wherein the illuminant comprises a discharge tube.
  6. The light source of claim 1,
    wherein the illuminant comprises a laser.
  7. The light source of claim 4,
    wherein the light emitting diode (310, 320) includes an element out of the group consisting of an AlInGaP-LED and an InGaN-LED.
  8. The light source of claim 5,
    wherein the discharge tube includes at least one element out of the group consisting of Sodium, Barium, Magnesium, Thallium, Chromium, Copper, Lithium, Mercury and Calcium.
  9. The light source of claims 7 or 8,
    wherein the light source further comprises a filter for selectively narrowing down the emission spectrum of the illuminant.
  10. The light source of claim 6,
    wherein the laser comprises a diode pumped Nd-YAG element which frequency is subsequently doubled.
  11. The light source of claim 6,
    wherein the laser comprises a red diode laser.
  12. A lamp (200, 300, 400) having
    a light source according to any one of claims 1 to 11.
EP10160812A 2010-04-23 2010-04-23 Light source Ceased EP2381244A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP10160812A EP2381244A1 (en) 2010-04-23 2010-04-23 Light source
PCT/IB2011/051694 WO2011132146A1 (en) 2010-04-23 2011-04-19 Light source

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP10160812A EP2381244A1 (en) 2010-04-23 2010-04-23 Light source

Publications (1)

Publication Number Publication Date
EP2381244A1 true EP2381244A1 (en) 2011-10-26

Family

ID=42782276

Family Applications (1)

Application Number Title Priority Date Filing Date
EP10160812A Ceased EP2381244A1 (en) 2010-04-23 2010-04-23 Light source

Country Status (2)

Country Link
EP (1) EP2381244A1 (en)
WO (1) WO2011132146A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020071287A1 (en) * 2000-12-13 2002-06-13 3M Innovative Properties Company Laser pointer with multiple color beams
US20040021420A1 (en) * 2002-03-06 2004-02-05 Toshiaki Tsuda Lamp unit and infrared night-vision system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20020071287A1 (en) * 2000-12-13 2002-06-13 3M Innovative Properties Company Laser pointer with multiple color beams
US20040021420A1 (en) * 2002-03-06 2004-02-05 Toshiaki Tsuda Lamp unit and infrared night-vision system

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
ANONYMOUS: "Lamp Assembly comprising LED and a Sodium Discharge Lamp", IP.COM JOURNAL, IP.COM INC., WEST HENRIETTA, NY, US, 21 January 2005 (2005-01-21), XP013022922, ISSN: 1533-0001 *
G. SCHRÖDER, H. TREIBER: "Technische Optik", 2007, VOGEL BUCHVERLAG, Würzburg, Germany, ISBN: 978-3-8343-3086-4, pages: 131 - 150, XP002603206 *
SHANG PING YING ET AL: "Charaterizing LEDs for Mixture of Colored LED light sources", ELECTRONIC MATERIALS AND PACKAGING, 2006. EMAP 2006. INTERNATIONAL CON FERENCE ON, IEEE, PI, 1 December 2006 (2006-12-01), pages 1 - 5, XP031202576, ISBN: 978-1-4244-0833-7 *
XIAOHUI QU ET AL: "Temperature Measurement Technique for Stabilizing the Light Output of RGB LED Lamps", IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT, IEEE SERVICE CENTER, PISCATAWAY, NJ, US LNKD- DOI:10.1109/TIM.2009.2025983, vol. 59, no. 3, 1 March 2010 (2010-03-01), pages 661 - 670, XP011283111, ISSN: 0018-9456 *

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