EP1098178A2 - Leuchtdichtenregelung einer beleuchteten Fläche - Google Patents

Leuchtdichtenregelung einer beleuchteten Fläche Download PDF

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Publication number
EP1098178A2
EP1098178A2 EP00660192A EP00660192A EP1098178A2 EP 1098178 A2 EP1098178 A2 EP 1098178A2 EP 00660192 A EP00660192 A EP 00660192A EP 00660192 A EP00660192 A EP 00660192A EP 1098178 A2 EP1098178 A2 EP 1098178A2
Authority
EP
European Patent Office
Prior art keywords
luminance
illuminated surface
brightness
environment
equipment
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.)
Withdrawn
Application number
EP00660192A
Other languages
English (en)
French (fr)
Other versions
EP1098178A3 (de
Inventor
Tapio Nieminen
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.)
Teknoware Oy
Original Assignee
Teknoware Oy
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 Teknoware Oy filed Critical Teknoware Oy
Publication of EP1098178A2 publication Critical patent/EP1098178A2/de
Publication of EP1098178A3 publication Critical patent/EP1098178A3/de
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
    • H05B47/10—Controlling the light source

Definitions

  • the present invention relates to a method and equipment for controlling the luminance of an illuminated surface, the method comprising the step of controlling the luminance of an illuminated surface.
  • the luminance of the surface When illuminating surfaces, such as signs, the luminance of the surface must be above a certain level. This way, the illuminated surface stands out from its environment in all conditions.
  • the illumination of signs and the like was arranged by allowing the illuminating light sources to burn at the brightness achieved by using a constant voltage, for instance, which feeds the light sources. In the beginning, the light sources then produce an unnecessarily high illuminance, since in most cases, even a lower illuminance would suffice to produce the necessary luminance.
  • a LED diode for instance, is a typically used light source. The illuminance of LED diodes decreases with time, and when used as described, the luminance achieved by the light source decreases and finally falls below a predefined level. Exact information on the falling of the luminance below a desired level cannot be obtained, which means that replacing the light sources must be done by estimate or after they have gone out completely.
  • Prior art does not take into consideration the luminance of the illuminated surface produced by external light or the brightness of the environment of the illuminated surface produced by external light.
  • External light such as room lighting or sunlight, may illuminate the environment of the illuminated surface so brightly that the illuminated surface does not stand out clearly enough from its environment. It would then be desirable to increase the illumination of the illuminated surface to a certain limit while the illumination of the environment increases. This way, the service life of the illuminating elements, such as LED diodes, would be increased, because the illuminating element needs not burn at full power all the time.
  • This object is achieved by a method of the invention characterized in that the method also comprises the steps of defining the brightness of the environment of the illuminated surface to achieve a reference brightness and controlling the luminance of the illuminated surface with an illuminating element depending on the level of the reference brightness.
  • the method of the invention is based on the idea that by defining the brightness of the environment of the illuminated surface and by controlling the luminance of the illuminated surface according to this brightness, a desired contrast is achieved between the illuminated surface and its environment.
  • the luminance is then controlled according to the changing brightness properties of the environment so that when the illumination of the environment increases, the illumination of the surface illuminated by an illuminating element is also increased, and correspondingly, when the illumination of the environment decreases, the illumination of the illuminated surface is also decreased.
  • the method provides a considerable advantage in that the contrast between a continuously illuminated surface, such as an exit sign, and its environment is kept within a certain limit. With respect to prior art, this method provides a considerable increase in the service life of the illuminating element, since the element is used at a power which is adequate to produce the required contrast between the illuminated surface and its environment.
  • the invention also relates to equipment for controlling the luminance of the illuminated surface, which equipment comprises an illuminating element which is arranged to illuminate the illuminated surface.
  • the equipment is characterized in that it also comprises an illumination sensor which is arranged to define the brightness of the environment of the illuminated surface, and control equipment which is arranged to control the illuminance produced by the illuminating element in response to the brightness of the environment of the illuminated surface.
  • Figure 1 shows a schematic of an illuminated surface 1 and the components arranged with it to implement the method of the invention.
  • the illuminated surface can be a sign, such as an exit sign or the like, which should stand out from the illumination conditions of the environment.
  • the equipment comprises an illuminating element 5 which is made up of LED diodes, for instance.
  • the purpose of the illuminating element is to illuminate the surface to be illuminated in such a manner that the surface achieves a predefined luminance in relation to the brightness of the environment of the illuminated surface.
  • the equipment of the invention shown in Figure 1 also comprises an illumination sensor 7 which enables the definition of the illumination of the environment of the illuminated surface.
  • the sensor 7 only determines the illumination of the environment and it is arranged so that the light reflecting from the illuminated surface does not reach the sensor detecting external light.
  • the sensor can be encased or located in a suitable manner.
  • the sensor 7 defines the brightness of the environment of the illuminated surface to produce a reference brightness.
  • the reference brightness refers to a reference signal proportional to the brightness of the environment.
  • the amount of light produced by the illuminating element is adjusted in relation to the reference variable defined in this manner. In other words, as the reference brightness increases, the luminance of the illuminated surface is increased to maintain a certain contrast between the surface and its environment.
  • control equipment of the illuminating element must contain listed value for reference brightness, for instance, and values of the illuminating element current corresponding to them or the like, by means of which a desired luminance can be made to correspond to a certain reference brightness.
  • the luminance of the illuminated surface is also defined.
  • An illumination sensor 2 is used to define the luminance.
  • the illumination sensor 2 defines in its entirety the brightness which is formed on the illuminated surface by the illuminating element and possible external light.
  • the luminance of the illuminated surface is defined to achieve a luminance signal, and the luminance of the illuminated surface is controlled with the illuminating element using control equipment 3 depending on the level of the reference brightness and the strength of the luminance signal.
  • the luminance produced by the illuminating element 5 is controlled in direct proportion to the reference brightness, for instance.
  • the brightness 10 of the environment of the illuminated surface increases linearly with time, and the figure shows the control of the luminance of the illuminated surface according to a preferred embodiment of the method.
  • the luminance of the surface is also increased from a first constant value 15 by illuminating it with the illuminating element.
  • the luminance of the surface is adjusted so that a desired contrast is maintained between the surface and the environment.
  • the luminance of the surface is kept lower than the brightness of the environment, but the luminance of the surface can also be higher than the brightness of the environment.
  • the luminance of the illuminated surface is increased linearly, but this can also be done stepwise.
  • the upper limit 12 is reached, and increasing the luminance is stopped using the illuminating element. In spite of the possible increase in the brightness of the environment, the luminance of the illuminated surface is then maintained at a second constant value 14.
  • the upper limit for the luminance produced by the illuminating element can, for instance, be determined in relation to the magnitude of the current of the LED diodes used for illumination in such a manner that an excess current which would unduly load the LED diodes is not allowed through them.
  • Figure 2 shows that when the brightness of the environment is zero or close to zero, the luminance is maintained at a constant level which is the minimum luminance.
  • an alarm signal is produced, if the desired luminance is not achieved.
  • the alarm signal provides advance warning of the fact that the condition of the illuminating element has deteriorated considerably and the element needs to be replaced.
  • the alarm signal can be transmitted to a person responsible for maintenance by visual means, for instance, using an alarm element 4, such as a LED diode or another signal light which can be located with the control equipment 3 controlling the illumination of the illuminated surface.
  • An alarm signal can also be produced if the brightness of the environment of the illuminated surface is so high that it is not possible to produce the desired contrast between the surface and its environment using the illuminating element.
  • Control equipment located with the illuminated surface can in practice control the illuminance by adjusting the current running through the illuminating element. Not only is the current adjustment simple to implement, but at the same time also the magnitude of the current running through the illuminating element will be measured, and the current can be limited to a predefined value.

Landscapes

  • Circuit Arrangement For Electric Light Sources In General (AREA)
  • Illuminated Signs And Luminous Advertising (AREA)
EP00660192A 1999-11-04 2000-10-27 Leuchtdichtenregelung einer beleuchteten Fläche Withdrawn EP1098178A3 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FI992386 1999-11-04
FI992386A FI111302B (fi) 1999-11-04 1999-11-04 Valaistavan pinnan pintakirkkauden säätö

Publications (2)

Publication Number Publication Date
EP1098178A2 true EP1098178A2 (de) 2001-05-09
EP1098178A3 EP1098178A3 (de) 2004-03-17

Family

ID=8555559

Family Applications (1)

Application Number Title Priority Date Filing Date
EP00660192A Withdrawn EP1098178A3 (de) 1999-11-04 2000-10-27 Leuchtdichtenregelung einer beleuchteten Fläche

Country Status (4)

Country Link
EP (1) EP1098178A3 (de)
FI (1) FI111302B (de)
NO (1) NO20005569L (de)
PL (1) PL343658A1 (de)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962600A (en) * 1975-02-14 1976-06-08 Arvin Hong Kong Ltd. Ambient light responsive illumination brightness control circuit
EP0263026A1 (de) * 1986-09-30 1988-04-06 SOCIETE D'ETUDES POUR LE DEVELOPPEMENT DES PRODUCTIONS ELECTRONIQUES société anonyme Elektrische Speiseanordnung einer Lichtquelle mit Halogenlampen
US4760389A (en) * 1985-11-27 1988-07-26 Hosiden Electronics Co. Ltd. Transmitting type display device
WO1997001240A1 (en) * 1995-06-20 1997-01-09 Thomson Consumer Electronics, Inc. Back lit electronic viewfinder
US5930059A (en) * 1998-01-02 1999-07-27 Equestrian Co., Ltd. Reflection mirror equipped with a luminance sensor

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3962600A (en) * 1975-02-14 1976-06-08 Arvin Hong Kong Ltd. Ambient light responsive illumination brightness control circuit
US4760389A (en) * 1985-11-27 1988-07-26 Hosiden Electronics Co. Ltd. Transmitting type display device
EP0263026A1 (de) * 1986-09-30 1988-04-06 SOCIETE D'ETUDES POUR LE DEVELOPPEMENT DES PRODUCTIONS ELECTRONIQUES société anonyme Elektrische Speiseanordnung einer Lichtquelle mit Halogenlampen
WO1997001240A1 (en) * 1995-06-20 1997-01-09 Thomson Consumer Electronics, Inc. Back lit electronic viewfinder
US5930059A (en) * 1998-01-02 1999-07-27 Equestrian Co., Ltd. Reflection mirror equipped with a luminance sensor

Also Published As

Publication number Publication date
PL343658A1 (en) 2001-05-07
FI19992386A (fi) 2001-05-05
FI111302B (fi) 2003-06-30
NO20005569L (no) 2001-05-07
EP1098178A3 (de) 2004-03-17
NO20005569D0 (no) 2000-11-03

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