EP0786799A1 - Lampe à incandescence avec réflecteur à spectre d'émission semblable à celui du soleil - Google Patents

Lampe à incandescence avec réflecteur à spectre d'émission semblable à celui du soleil Download PDF

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Publication number
EP0786799A1
EP0786799A1 EP97300451A EP97300451A EP0786799A1 EP 0786799 A1 EP0786799 A1 EP 0786799A1 EP 97300451 A EP97300451 A EP 97300451A EP 97300451 A EP97300451 A EP 97300451A EP 0786799 A1 EP0786799 A1 EP 0786799A1
Authority
EP
European Patent Office
Prior art keywords
lamp
dichroic filter
light
reflector
light source
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.)
Granted
Application number
EP97300451A
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German (de)
English (en)
Other versions
EP0786799B1 (fr
Inventor
Wilmert Cyriel Stefaan De Bosscher
Joseph Guido Marie Gielen
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.)
Flowil International Lighting Holding BV
Original Assignee
Flowil International Lighting Holding BV
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Filing date
Publication date
Application filed by Flowil International Lighting Holding BV filed Critical Flowil International Lighting Holding BV
Publication of EP0786799A1 publication Critical patent/EP0786799A1/fr
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01K—ELECTRIC INCANDESCENT LAMPS
    • H01K1/00—Details
    • H01K1/26—Screens; Filters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V9/00—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters
    • F21V9/02—Elements for modifying spectral properties, polarisation or intensity of the light emitted, e.g. filters for simulating daylight

Definitions

  • the present invention relates to an incandescent reflector lamp which emits light with a spectral output that substantially simulates sunlight, at least over the visible range of the electromagnetic spectrum.
  • Incandescent daylight lamps having a blue coating are also known.
  • the blue coating results in a partial filtering of the red portion of the spectrum from the light source.
  • the spectral output has no real correlation with the spectrum of sunlight.
  • Another lamp is known from DE-A-3931950.
  • This lamp uses an incandescent halogen burner as the light source and incorporates a cold light reflector on its parabolic surface behind the light source.
  • the lamp further includes a separate filter, which is preferably a daylight filter made from a dichroic material, which provides a colour temperature of approximately 5600K. Although this lamp is said to produce an agreeable cool light, the filter is just a standard dichroic filter.
  • Reflector lamps are lamps which have an integral coating on the generally parabolic surface located behind the light source, usually a dichroic coating, in order to reflect light back past the light source and through the front glass.
  • the known daylight filters generally reduce the proportion of the yellow and red light being transmitted.
  • these filters are formed as dichroic coatings, they do not absorb but reflect the unwanted radiation back to the parabolic reflector, whereupon the light is reflected back again towards the front glass.
  • These secondary and multiple reflections will increase the relative amount of yellow and red light hitting the dichroic coating of the filter, which also increases the amount of yellow and red light being transmitted. To correct this, the transmission of yellow and red light must be significantly lower than the theoretical value.
  • the present invention provides a reflector lamp having a halogen light source and a front glass though which light is transmitted, the front glass having a dichroic filter to convert the light from the light source to light having colour coordinates approximately those of sunlight, characterised in that the transmission properties of the dichroic filter have been tuned to take account of secondary and multiple reflections from the reflector so that the lamp has a spectral emission substantially the same as sunlight, at least over the visible range.
  • the lamp allows a reflector to be used whilst producing a light that more closely resembles sunlight.
  • the spectral emission has a coefficient of correlation with the spectrum of sunlight over the visible region of between 0.7 and 1.0, preferably between 0.8 and 1.0, and most preferably between 0.85 and 1.0. In existing products, generally no correlation exists and in many cases the opposite tendency is found producing negative values for the correlation coefficient.
  • the transmission of light through the filter of the front glass between the range of 400 and 480nm is higher, and between 580 and 700nm is lower, than the predicted values for a lamp not having a reflector. This therefore reduces the relative amount of yellow and red light being emitted and produces light from a reflector lamp whose spectral emission is closer to that of sunlight.
  • the transmission of light through the front glass of the lamp over the range 400 to 480nm is greater than 90%.
  • the filter produces a transmission curve that has a single broad peak with no minima between 400 and 580 nm, most preferably between 400 and 480nm.
  • the transmission of light over the range 580 to 760nm is below 25%.
  • the present invention provides a reflector lamp having a halogen light source and a front glass through which light is transmitted, the front glass having a dichroic filter to convert the light from the light source to light having colour coordinates approximately those of sunlight, characterised in that the transmission curve of the dichroic filter has a single broad peak which extends between 400 and 480 nm.
  • the transmission curve exhibits a minimum between 400 and 480nm, usually at around 430nm.
  • the spectral emission curve of the lamp closely resembles that of sunlight over the visible region having a single peak in the region between 430 and 530nm, preferably the width of the peak is narrower than that of the sunlight spectrum.
  • Medical tests have shown that the human eye can focus more easily on single peaked spectral light distributions, resulting in better vision for contrast and detail. By decreasing the width of the single peak, this effect can be increased whilst maintaining a good colour rendering index (CRI).
  • CRI colour rendering index
  • the lamp has a CRI of greater than 90%.
  • the CRI is greater than 93% and in a most preferred embodiment the CRI is equal to or greater than 95%.
  • a preferred range for the CRI is between 93 and 97%.
  • the present invention provides a reflector lamp having a halogen light source and a front glass through which light is transmitted, the front glass having a dichroic filter to convert the light from the light source to light having colour coordinates approximately those of sunlight, characterised in that the lamp produces an emission spectrum having a single peaked curve, the peak laying between 450 and 580 nm.
  • the peak is at 480 nm as this correlates well with the peak of the sunlight spectrum.
  • just having a single peaked spectrum provides advantages in its own right, because of the increase in ease with which the eye can focus.
  • the dichroic filter comprises alternating layers of ZnS and SiO 2 .
  • the filter consists of the following 8 layers:
  • the dichroic filter is a coating which is integral with the front glass of the lamp, preferably coated on the inside of the front glass.
  • the present invention provides a reflector lamp having a halogen light source and a front glass through which light is transmitted, the front glass having a dichroic filter to convert the light from the light source to light having colour coordinates approximately those of sunlight, characterised in that the dichroic filter is a coating applied to the inside surface of the front glass and in that it consists of alternating layers of ZnS and SiO 2 .
  • This coating is preferably applied by the molybdenum boat thermal evaporation process using ZnS and SiO as evaporation materials.
  • the SiO is evaporated in a partial oxygen atmosphere to form SiO 2 layers.
  • This method is advantageous because it is considerably cheaper to use than other evaporation processes, such as the electron beam gun evaporation process, with SiO 2 and TiO 2 as evaporation materials, used by Balzers in the production of their above mentioned "TL60" filter.
  • the reflector may be a standard reflector material which reflects substantially all of the visible light incident on it back into the lamp, or it may be designed to reflect only selected wavelengths, for example, a cold light reflector which may allow infrared light to pass through.
  • the preferred light source is an incandescent halogen capsule or burner with a colour temperature of between 2700 and 3200K, for example, a 100W high volt halogen lamp or at least a 50W low volt lamp.
  • a colour temperature of between 2700 and 3200K for example, a 100W high volt halogen lamp or at least a 50W low volt lamp.
  • the emission from the lamp itself prefferably has a colour temperature higher than 5000K, while maintaining the smallest possible deviation from the block body locus of a chromaticity diagram.
  • the lamp has an emission with a colour temperature of greater than 6000K, preferably as high as 6500K, since this provides a person using the light with better conditions for reading due to improved contrast and vision.
  • the soothing properties and the improved contrast and vision can be achieved by the single peaked distribution without having such a high colour temperature, for example, 4000K.
  • a colour temperature may be produced by a high volt 50W lamp, which may be more appropriate for existing desk top fixtures which usually only allow up to a maximum of 60W.
  • the single peak of the emission curve would be at approximately 580 nm, rather than 480 nm for the 6500K version.
  • a dichroic filter is coated directly onto the light source capsule itself.
  • the present invention provides an incandescent halogen light source for a lamp wherein the light source is coated with a dichroic filter to emit light having colour coordinates and a spectral emission substantially the same as sunlight.
  • the light source is incorporated in a reflector lamp.
  • the preferred illuminance level for the lamp is between 1100 and 1700 lx, preferably between 1200 and 1650 lx, and most preferably at 1350 lx.
  • a homogeneous illumination of the work space by the lamp is important, especially if the lamp is to maximise its soothing and its improved contrast and vision properties.
  • the reflector should therefore have a large beam angle, for example, 50° or more, preferably 60° or greater for desk top applications, in order to spread the beam of desired illuminance over a reasonable area, rather than just a small spot.
  • FIG. 1 there is shown an embodiment of a preferred reflector lamp.
  • the lamp comprises a front glass 1, a reflector 2, an incandescent light source 3, often referred to as a "burner", and a socket 4.
  • the lamp has a dichroic filter 5 coated on the inside of the front glass 1.
  • the coating may be applied by any suitable technique, the preferred technique being a standard molybdenum boat thermal evaporation process using ZnS and SiO as evaporation materials.
  • the SiO is evaporated in an oxygen enriched atmosphere to form SiO 2 layers.
  • Other techniques, such as electron beam gun evaporation, may also be used although tend to be more expensive.
  • the transmission properties of the dichroic filter are tuned so that the spectral emission of the lamp is substantially the same as sunlight.
  • the lamp consists of a high voltage hard glass incandescent halogen burner 3, focused inside a parabolic reflector 2 with a rim diameter of 95mm.
  • the reflector consists of a moulded parabolic glass portion of the lamp envelope inside which a standard semi durable cold light mirror material is coated. The coating reflects visible light but is transparent to infrared.
  • a front glass 1 is glued to the reflector 2 to prevent dust and other pollutants from entering the lamp, as well as providing protection in the event of the burner 3 exploding and a UV-stop filter.
  • the front glass 1 has a coating 5 applied to its inside surface which converts the light emitted from the high voltage burner into a single peaked spectrum with a colour temperature of at least 6000K.
  • the coating 5 consists of 8 layers of alternating ZnS and SiO 2 with the following thicknesses: Layer Nr. Material Thickness (nm) 1 ZnS 76.73 2 SiO 2 110.74 3 ZnS 65.04 4 SiO 2 103.86 5 ZnS 71.59 6 SiO 2 118.81 7 ZnS 102.94 8 SiO 2 80.38
  • the transmission properties of this coating 5 are shown in Figure 6.
  • the coating 5 in this example achieves a colour temperature conversion of 2800K to between 6000 to 6500K when used with a 100W, high volt light source or at least a 50W low volt light source.
  • the spectral outputs of the different curves when compared to that of the sun correlate as follows: light source correlation coefficient sun 1.00 preferred embodiment of the present invention 0.86 halogen lamp -0.51 neodymium containing lamp -0.42 blue coated incandescent daylight lamp -0.53 fluorescent daylight lamp 0.40
  • Figure 3 in addition to clearly showing that the single peaked spectral emission of the preferred lamp closely matches that of sunlight, also shows that there is improved kurtosis, ie. sharpness of the peak. This allows for easier focusing of the human eye whilst maintaining the high colour rendering index.
  • the filters exhibit transmission minima between approximately 420 to 430nm.
  • the preferred filter has a transmission curve that exhibits a single broad peak in the blue region that spans between about 400 and 500nm.
  • the preferred filter also shows lower transmission in the yellow and red region of the spectrum compared to the Balzer's "TL60" daylight filter shown in Figure 4.
  • the reflector 2 may be of any type, eg. smooth, faceted etc, and its transmission properties may be dictated by the heat resisting properties of the socket 4 and/or the light fitting (not shown).
  • the lamp may, for example, be a 75W lamp with a 25° spread angle for ceiling mount applications, or perhaps a 50W lamp with a 50° spread angle or a 50mm diameter, 50W lamp with a 60° spread angle for desk lamp applications. In all these cases, it may be necessary to adjust the coating or filter in order to compensate for the different colour temperatures of the burners and for the different secondary and multiple reflections of the various reflector types.
  • a lamp which does not require a complex construction or extra parts to hold a filter; which in its most preferred embodiment has improved daylight reproducing abilities; and which can provide a soothing light that enables optimal contrast and homogeneous illumination of a reading surface.

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Optical Filters (AREA)
EP19970300451 1996-01-24 1997-01-24 Lampe à incandescence avec réflecteur à spectre d'émission semblable à celui du soleil Expired - Lifetime EP0786799B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GBGB9601402.2A GB9601402D0 (en) 1996-01-24 1996-01-24 Incandescent reflector lamp with sun-like spectral output
GB9601402 1996-01-24

Publications (2)

Publication Number Publication Date
EP0786799A1 true EP0786799A1 (fr) 1997-07-30
EP0786799B1 EP0786799B1 (fr) 2002-04-10

Family

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Application Number Title Priority Date Filing Date
EP19970300451 Expired - Lifetime EP0786799B1 (fr) 1996-01-24 1997-01-24 Lampe à incandescence avec réflecteur à spectre d'émission semblable à celui du soleil

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EP (1) EP0786799B1 (fr)
DE (1) DE69711734T2 (fr)
GB (1) GB9601402D0 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0883889A1 (fr) * 1996-02-27 1998-12-16 Tailored Lighting Inc. Nouvelle lampe lumiere du jour
EP1399941A2 (fr) * 2001-06-07 2004-03-24 McGuire, Kevin P. Lampe subaquatique
CN102352970A (zh) * 2011-08-09 2012-02-15 中山大学 一种新型led光源及其照明装置

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102012009581A1 (de) 2011-05-15 2012-11-15 Julia von Chamier Verfahren und Vorrichtung zur Beleuchtung von Räumen

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2831966A (en) * 1954-04-19 1958-04-22 Analite Corp Lighting fixtures
US4125775A (en) * 1977-10-05 1978-11-14 Corning Glass Works Solar simulator
SU1008170A1 (ru) * 1981-10-12 1983-03-30 Государственный научно-исследовательский институт стекла Стекло дл светофильтров
DE3931950A1 (de) * 1989-09-25 1991-04-04 Alexander Kaiser Leuchte
JPH0821785A (ja) * 1994-07-08 1996-01-23 Mitsubishi Heavy Ind Ltd 日射装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2831966A (en) * 1954-04-19 1958-04-22 Analite Corp Lighting fixtures
US4125775A (en) * 1977-10-05 1978-11-14 Corning Glass Works Solar simulator
SU1008170A1 (ru) * 1981-10-12 1983-03-30 Государственный научно-исследовательский институт стекла Стекло дл светофильтров
DE3931950A1 (de) * 1989-09-25 1991-04-04 Alexander Kaiser Leuchte
JPH0821785A (ja) * 1994-07-08 1996-01-23 Mitsubishi Heavy Ind Ltd 日射装置

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 8406, Derwent World Patents Index; Class L01, AN 84-035659, XP002029718 *
PATENT ABSTRACTS OF JAPAN vol. 096, no. 005 31 May 1996 (1996-05-31) *

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0883889A1 (fr) * 1996-02-27 1998-12-16 Tailored Lighting Inc. Nouvelle lampe lumiere du jour
EP0883889B1 (fr) * 1996-02-27 2001-01-10 Tailored Lighting Inc. Nouvelle lampe lumiere du jour
EP1399941A2 (fr) * 2001-06-07 2004-03-24 McGuire, Kevin P. Lampe subaquatique
EP1399941A4 (fr) * 2001-06-07 2006-06-21 Kevin P Mcguire Lampe subaquatique
CN102352970A (zh) * 2011-08-09 2012-02-15 中山大学 一种新型led光源及其照明装置
CN102352970B (zh) * 2011-08-09 2015-07-22 中山大学 一种led光源及其照明装置

Also Published As

Publication number Publication date
GB9601402D0 (en) 1996-03-27
DE69711734T2 (de) 2002-11-14
EP0786799B1 (fr) 2002-04-10
DE69711734D1 (de) 2002-05-16

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