WO2017097659A1 - Dispositif capteur et système d'éclairage - Google Patents

Dispositif capteur et système d'éclairage Download PDF

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Publication number
WO2017097659A1
WO2017097659A1 PCT/EP2016/079410 EP2016079410W WO2017097659A1 WO 2017097659 A1 WO2017097659 A1 WO 2017097659A1 EP 2016079410 W EP2016079410 W EP 2016079410W WO 2017097659 A1 WO2017097659 A1 WO 2017097659A1
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WO
WIPO (PCT)
Prior art keywords
light
aperture
etendue
sensor device
sensor
Prior art date
Application number
PCT/EP2016/079410
Other languages
English (en)
Inventor
Fernando MUNOZ FERNANDEZ
Original Assignee
Philips Lighting Holding B.V.
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 Lighting Holding B.V. filed Critical Philips Lighting Holding B.V.
Publication of WO2017097659A1 publication Critical patent/WO2017097659A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4204—Photometry, e.g. photographic exposure meter using electric radiation detectors with determination of ambient light
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/0266—Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G01J1/0407—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings
    • G01J1/0411—Optical elements not provided otherwise, e.g. manifolds, windows, holograms, gratings using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/04—Optical or mechanical part supplementary adjustable parts
    • G01J1/06—Restricting the angle of incident light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
    • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
    • G02B19/0009—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only
    • G02B19/0014—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having refractive surfaces only at least one surface having optical power
    • 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
    • G02B19/0038—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with ambient light
    • 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
    • G02B19/0076—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a detector
    • 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
    • H05B47/105—Controlling the light source in response to determined parameters
    • H05B47/11—Controlling the light source in response to determined parameters by determining the brightness or colour temperature of ambient light
    • 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
    • H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

Definitions

  • the present invention relates to a sensor device comprising a housing comprising an aperture positioned on an optical axis extending through said aperture; and a light sensor disposed in said housing and positioned on the optical axis.
  • the present invention further relates to a lighting system including such a sensor device.
  • indoor lighting systems may tailor their luminous output based on the levels of ambient (natural) light in the area as measured by a sensor device of the lighting system.
  • the lighting system may maintain a constant level of illumination within the area by varying the luminous output of its one or more lighting devices in response to the measured levels of ambient light and/or only engage its one or more lighting devices in case light levels in the area drop below a certain threshold, such that energy can be preserved in case the ambient light levels are sufficiently high in the area.
  • Such lighting systems are sometimes referred to as daylight harvesting systems.
  • the sensor device In order to obtain an accurate determination in a particular area, such as a work area illuminated by a lighting system, it may be necessary for the sensor device to only collect ambient light reflected by the work area, i.e. to exclude ambient light directly incident on the sensor device. This is typically achieved by designing the sensor device such that it has a truncated angular response, i.e. it does not collect light rays having angles of incidence that exceed a cut-off angle. In many daylight harvesting systems, such a cut-off angle is typically chosen about 40°.
  • Such a light sensor has an etendue of n.n.A.sin 2 (6), where n is the index of refraction of the medium through which the light travels, A is the sensor area and ⁇ is the acceptance angle of the light rays entering the light sensor.
  • n the index of refraction of the medium through which the light travels
  • A the sensor area
  • ⁇ the acceptance angle of the light rays entering the light sensor.
  • a daylight harvesting apparatus for controlling an amount of light in an associated work area comprises a sensor assembly for sensing an amount of illumination in a proximity of the apparatus; a controller for receiving a value representing the amount of illumination and for determining an lamp control signal to be provided based on the amount of illumination; and an artificial light source for providing light, corresponding to the lamp control signal, to the work area.
  • the sensor assembly includes an optical telescope to focus incident light on the photodetector in the sensor assembly.
  • such an arrangement does not provide the required cut-off in incident angles of the light rays being collected by the photodetector in this sensor assembly and is therefore unable to distinguish between reflected ambient light and ambient light directly incident on the sensor assembly.
  • the present invention seeks to provide a compact and/or aesthetically pleasing sensor device that can achieve the desired cut-off in incident light ray angles.
  • the present invention further seeks to provide a lighting system comprising such a sensor device.
  • a sensor device comprising a housing comprising an aperture positioned on an optical axis extending through said aperture; a light sensor disposed in said housing and positioned on the optical axis, the light sensor having a smaller area than the aperture; and an etendue-limited lens arrangement in between the aperture and the light sensor, wherein the etendue-limited lens arrangement is dimensioned to exclusively redirect light from a virtual source to the light sensor, the virtual source having a smaller diameter than the aperture and being positioned on the optical axis in between the etendue-limited lens arrangement and the aperture such that incident light rays through the aperture under an angle relative to the optical axis exceeding a defined angle cannot pass through the virtual source.
  • the term "etendue-limited lens” refers to a lens having a design that approaches the thermodynamic limit of concentration. In other words, it refers to a lens that is limited by the etendue because no more energy can be collected over this limit.
  • the term "virtual source” refers to a virtual source of light rays.
  • a virtual source is similar to a virtual object, wherein, instead of being actually emitted from it, light rays are directed to the virtual object and then passing through it.
  • a lens arrangement dimensioned to only project light onto the light sensor if such light passes through, i.e. is generated by, a virtual source in between the lens arrangement and the aperture facilitates the use of having a large aperture than the light sensor, as the effective aperture for the light sensor is defined by the virtual source.
  • the use of a lens that is spatially separated from the light sensor increases the design freedom of the lens as it may be larger than the light sensor and further allows for a straightforward and therefore more cost-effective manufacturing of the sensor device.
  • the etendue-limited lens arrangement is dimensioned to redirect the light generated by the virtual source to the light sensor in accordance with the edge-ray principle.
  • Such a non-imaging lens arrangement therefore preserves the etendue between the virtual source and the light sensor, thus maximising the energy transfer between the virtual source and the light sensor.
  • the etendue-limited lens arrangement may be implemented as a single lens or as a system of lenses.
  • the etendue-limited lens arrangement is implemented by a single lens in order to achieve a particularly compact lens arrangement.
  • the etendue-limited lens arrangement preferably may comprise a rotationally symmetric lens having an aspheric light entry surface and an aspheric light exit surface in order to achieve the desired redirection of the incident light from the virtual light source to the light sensor in accordance with the edge-ray principle.
  • the rotationally symmetric lens may further comprise a side surface extending between the aspheric light entry surface and the aspheric light exit surface. This for instance facilitates handling and mounting of the lens, e.g. in a lens holder.
  • the sensor device further comprises a lens holder holding the etendue-limited lens arrangement, the lens holder comprising a plurality of legs having a defined length, wherein the light sensor is mounted on a carrier comprising a plurality of recesses, each of the legs mating with one of said recesses.
  • the lens arrangement is always placed at the correct distance from the light sensor, thus facilitating straightforward and therefore cost-effective assembly of the sensor device.
  • the etendue-limited lens arrangement comprises an etendue-limited lens having a central lens portion for redirecting a first portion of the incident light rays passing through the virtual source, and a peripheral total internal reflection (TIR) lens portion around the central lens portion for redirecting a second portion of the incident light rays passing through the virtual source.
  • TIR total internal reflection
  • the peripheral TIR lens portion may further act as the lens holder of the central lens portion in the sense that the peripheral TIR lens portion may include a plurality of legs having a defined length as explained above.
  • the defined angle i.e. the acceptance angle of the virtual source, preferably is in the range of 30-50°. More preferably, the defined angle is about 40°, in order to minimize the amount of direct ambient light reaching the light sensor.
  • the aperture of the sensor device may be as small as possible within the chosen manufacturing techniques. For example, the aperture may have a diameter in the range of 1-3 mm although other diameters are equally feasible.
  • the sensor device is a multi-sensor device.
  • the housing further comprises at least one further aperture, wherein each further aperture is positioned on a respective further optical axis extending through said further aperture; and at least one further light sensor disposed in said housing wherein each further light sensor is positioned on a respective one of said further optical axes.
  • the light sensor and the at least one further light sensor are mounted on a planar surface of a single carrier.
  • the sensor device may further comprise at least one further etendue-limited lens arrangement in between a further aperture and a further light sensor, wherein the further etendue-limited lens arrangement is dimensioned to exclusively redirect light from a further virtual source to a further light sensor, the further virtual source having a smaller diameter than the further aperture and being positioned on the further optical axis in between the further etendue-limited lens arrangement and the further aperture such that incident light rays through the further aperture under an angle relative to the further optical axis exceeding a defined further angle cannot pass through the further virtual source.
  • Each of the etendue-limited lens arrangement and at least one further etendue-limited lens arrangement may comprise a respective lens holder holding the lens
  • each lens holder comprising a plurality of legs having a defined length, wherein the legs of different lens holders have different defined lengths; and each of the plurality of legs mate with matching recesses in the single carrier.
  • a lighting system comprising the sensor device of any of the above embodiments; a controller responsive to the sensor device; and at least one lighting device under control of the controller.
  • the controller is adapted to control the at least one lighting device in response to the sensor device such as to compensate for a fluctuation in a daylight contribution to a level of illumination in a target area illuminated by the at least one lighting device.
  • the controller may form part of a daylight harvesting system to minimize the amount of artificial light that has to be generated by the at least one lighting device in order to achieve a desired lighting level in the target area.
  • FIG. 1 schematically depicts a sensor device according to an embodiment
  • FIG. 2 and FIG. 3 schematically depict the effect of changing certain design parameters of such a sensor device on the optical performance of the sensor device;
  • FIG. 4 schematically depicts an example design rule for the lens arrangement of a sensor device according to embodiments of the present invention
  • FIG. 5 schematically depicts a cross-section of a sensor device according to an embodiment
  • FIG. 6 schematically depicts a top view of the sensor device of FIG. 5;
  • FIG. 7 schematically depicts a sensor device according to another embodiment
  • FIG. 8 schematically depicts a sensor device according to yet another embodiment.
  • FIG. 9 schematically depicts a lighting system according to an embodiment.
  • FIG. 1 schematically depicts a cross-section of a sensor device 10 according to an embodiment of the present invention.
  • the sensor device 10 comprises a housing 11 including a lid or top surface 13 including an aperture 15, e.g. a diaphragm or the like, which preferably is a circular aperture.
  • the aperture 15 has a diameter D, which is related to the optical performance of the sensor device 10 as will be explained in more detail below.
  • the aperture 15 may be made as small as is possible in the manufacturing process of the lid or top surface 13, for example the aperture 15 may have a diameter D in the range of 1.0 - 3.0 mm, such as for example a diameter D of about 1.5 mm.
  • the housing 1 1 and its lid or top surface 13 may be made of any suitable material, e.g. a metal or metal alloy, a plastics material or combinations thereof, and may be made using any suitable manufacturing process, e.g. casting, moulding, stamping, and so on.
  • the sensor device 10 comprising at least one light sensor 30 disposed in its housing 1 1.
  • the light sensor 30 may be disposed in the housing 1 1 in any suitable manner, for instance on a carrier such as a PCB. Any suitable light sensor 30 may be used for this purpose.
  • the light sensor 30 is a light sensor having sensitivity in the visible part of the electromagnetic spectrum, i.e. is a visible light sensor.
  • the light sensor 30 for instance may be implemented as a photodetector, e.g. a photo diode.
  • the light sensor 30 typically has a light sensitive area that is substantially smaller than the area of the aperture 15.
  • the light sensor 30 may have an area below 0.1 mm 2 , e.g. an area of 0.01 mm 2 or below.
  • a non-limiting example of a suitable light sensor 30 is the NOA1212 ambient light sensor marketed by the ON Semiconductor company, Phoenix (AZ), USA but it should be understood that many alternative suitable light sensors are readily available.
  • the large area of the aperture 15 compared to the area of the light sensor 30 means that the aperture 15 has a much larger etendue than the light sensor 30. As will be understood from the foregoing, such an arrangement cannot produce the desired sharp cut-off in the angles of incidence of the light rays to be accepted by the light sensor 30 as for such a sharp cut-off the optical system must be near to its thermodynamical limit.
  • the sensor device 10 comprises an etendue-limited lens arrangement, here depicted by a single etendue-limited lens 20, which lens arrangement is designed, i.e. dimensioned, based on a virtual source 25 on the optical axis 17 of the sensor device 10, which virtual source 25 is dimensioned to match the etendue of the light sensor 30 and this positioned on the optical axis 17 in between the etendue-limited lens arrangement, e.g. the etendue-limited lens 20 and the aperture 15 at a distance L from the aperture 15 such that only light rays 28 having an absolute angle of incidence ⁇ or less relative to the optical axis 17 can pass through the virtual source 25.
  • the etendue-limited lens arrangement here depicted by a single etendue-limited lens 20, which lens arrangement is designed, i.e. dimensioned, based on a virtual source 25 on the optical axis 17 of the sensor device 10, which virtual source 25 is dimensioned to match the etendu
  • the etendue-limited lens 20 is a rotationally symmetric lens comprising an aspherical light entry surface 21 and an aspherical light exit surface 23.
  • a side surface 22 extending between the aspheric light entry surface 21 and the aspheric light exit surface 23 preferably also forms part of the rotationally symmetric lens.
  • the side surface 22 may define an edge surface of the etendue-limited lens 20 and may be tapered due to a difference in respective diameters of the aspherical light entry surface 21 and the aspheric light exit surface 23.
  • the side surface 22 may have any suitable shape, e.g. a planar, convex or concave shape.
  • a planar shape may be preferable from a manufacturing perspective as it facilitates straightforward manufacturing of the etendue-limited lens 20.
  • the side surface 22 may be omitted.
  • the etendue-limited lens arrangement e.g. a single etendue-limited lens 20 may be designed in accordance with the edge-ray principle, in which rays of light generated at the respective edges of a light source, here the virtual light source 25, are projected onto the respective edges of a receiver, here the light sensor 30, with rays of light generated in between the respective edges of the light source are projected in between the respective edges of the receiver, such that all light generated by the light source is projected onto the receiver, thereby preserving etendue.
  • a lens arrangement typically is a non-imaging lens arrangement.
  • the edge-ray principle is explained in more detail by H.Ries et al. in "Edge-ray principle of nonimaging optics", J. Opt. Soc.
  • the etendue-limited lens arrangement e.g. the single etendue-limited lens 20
  • the etendue-limited lens arrangement exclusively projects light originating from the virtual source 25 onto the light sensor 30, whilst light rays entering the etendue-limited lens arrangement from outside the virtual source 25 are projected outside the area of the light sensor 30 and as such are not accepted by the light sensor 30.
  • a sensor device 10 in which a sharp cut-off in the light rays accepted by the sensor device 10 is provided despite a mismatch in etendue between the aperture 15 and the light sensor 30. Because the aperture 15 no longer needs to be shaped in a particular manner to achieve the desired cut-off, a simple aperture 15 such as a pinhole or the like may be provided, which may be kept as small as possible in order to improve the aesthetic appearance of the sensor device 10.
  • FIG. 2 schematically depicts the relationship between the diameter of the aperture 15 and the position of the virtual source 25 on the optical axis 17 of the sensor device 10.
  • the diameter D of the aperture 15 has been increased, which results in an increased amount of light rays 29 having an angle of incidence exceeding the desired acceptance angle ⁇ of the sensor device 10 being able to enter the housing 1 1 without passing through the virtual source 25 when kept at original distance L from the aperture 15, i.e. the light rays 28 defining the edge of the cone of light rays passing through the virtual source 25 no longer coincide with the edge of the diaphragm 15.
  • the distance L of the virtual source 25 to the aperture 15 must be increased when increasing the diameter D of the aperture to ensure that the sensor device 10 maintains its desired acceptance angle characteristics, i.e. the light rays 28 defining the edge of the cone of light rays passing through the virtual source 25 coincide with the edge of the diaphragm 15. From this, it may be concluded that the overall size (height) of the sensor device 10 may be minimized by minimizing the area (diameter) of the aperture 15. In the optical limit, the diameter of the diaphragm 15 coincides with the diameter of the virtual source 25 such that no virtual source 25 would be present but instead the diaphragm 15 would become the actual light source of the sensor device 10. However, as previously explained, such small diaphragms 15 cannot be routinely manufactured.
  • optical artefacts e.g. vignetting
  • a practical range of aperture diameters at which substantial artefacts may be avoided whilst achieving a compact sensor device 10 is 1-3 mm.
  • FIG. 4 shows an example design principle for the etendue-limited lens arrangement in the sensor device 10 according to embodiments of the present invention.
  • the etendue-limited lens arrangement is implemented as a single lens 20.
  • the design principle is based on the imposed condition that the etendues from emitter (the virtual source 25) to the lens 20 to be designed and from the lens 20 to the receiver (the light sensor 30) are equal and that the lens 20 may have an edge 22, which may be a thin or thick edge 22 in order to facilitate handling and mounting of the lens 20, the etendue from E1E2 defining the edges of the virtual source 25 to the entrance aperture NM, i.e.
  • points M and Y are chosen as the mirror image of points N and X respectively when mirrored by the optical axis 17, i.e. are chosen on mirror images of the hyperbolae hE and hR respectively.
  • the opposing lens surfaces 21 and 23 meet in these endpoints, in which case the lens 20 may not comprise a side surface 22 extending between these opposing lens surfaces, although such a side surface may be preferable as it facilitates handling of the lens 20 and mounting of the lens 20, e.g. in a lens holder.
  • the points N, X and M, Y define the (optical) boundary conditions of the lens 20, i.e. the boundaries of the incident light to be imaged onto the light sensor 30. Consequently, all light incident on the lens 20 in between these boundaries will be projected onto the light sensor 30 regardless of the shape of the light entry surface 21 and the light exit surface 23 of the lens 20. In other words, the light entry surface 21 and the light exit surface 23 may have any suitable shape within the boundary conditions of the lens.
  • FIG. 5 schematically depicts a cross-section
  • FIG. 6 schematically depicts a top view of a particularly advantageous embodiment of an etendue-limited lens 20.
  • the lens 20 is held in a lens holder 40 comprising a plurality of legs 42, e.g. three or four legs 42, which legs 42 have a defined height H that ensures that when the lens holder 40 is positioned on a receiving surface on which the light sensor 30 is positioned, e.g. a carrier 50 such as a PCB carrying the light sensor 30, the distance between the lens 20 and the light sensor 30 are positioned at the appropriate distance from each other in order to achieve the desired optical performance, i.e. the etendue matching between the virtual source 25 and the light sensor 30 as previously explained.
  • a carrier 50 such as a PCB carrying the light sensor 30
  • the legs 42 may include mating portions 43 for mating with corresponding recesses or holes 51 in the carrier 50, such that the lens holder 40 can be correctly positioned on the optical axis 17 over the light sensor 30 in a straightforward manner. In this manner, the sensor device 10 can be easily assembled in a correct manner without requiring complex alignment procedures for correctly positioning the lens 20 over the light sensor 30.
  • the lens holder 40 may have a body 41 from which the legs 40 extend and in which the lens 20 is held.
  • the lens holder 40 may be a discrete component or may form an integral part of the lens 20.
  • the lens holder 40 is an integral part of the lens 20.
  • Such an integral design may be easily manufactured, in particular when made of an optical grade polymer such as polycarbonate, polyethylene teraphtalate, poly (methyl methacrylate) and so on, in which case the integral design may be manufactured for example using moulding techniques.
  • the lens 20 in any of the embodiments of the present invention may be made of any suitable material capable of implementing the desired optical function, e.g. an optical grade polymer or glass.
  • FIG. 7 schematically depicts a cross-section of a sensor device 10 in which the lens 20 comprises a central lens portion 20' and a peripheral lens portion 20", which typically is a total internal reflection lens portion.
  • the light collected by the central lens portion 20' i.e. a first portion of the incident light rays passing through the virtual source 25, is a subset of the total etendue of the light collected by the whole optical system including the central lens portion 20' and the peripheral TIR lens portion 20".
  • the peripheral lens portion 20" typically collects a second portion of the incident light rays passing through the virtual source 25, with the combined first and second portions corresponding to the total etendue of the light collected by the whole optical system.
  • the subset of the total etendue collected by the central lens portion 20' has the same area extension but a reduced angle extension compared to the total etendue of the light collected by the optical system.
  • the optical system formed by the central lens portion 20' and the peripheral TIR lens portion 20" acts as a total internal reflection lens.
  • Such a lens 20 is particularly advantageous in embodiments where the amount of light not exceeding a particular acceptance angle harvested by the light sensor 30 should be maximized, e.g. to improve the intensity and stability of the sensor signal produced by the light sensor 30 (e.g. reduce noise levels). This increases the etendue of the light sensor 30 as a larger spread of light is accepted by the light sensor 30.
  • the optical performance of the overall optical system i.e. the sensor device 10
  • is to remain unaltered i.e.
  • the diameter D of the diaphragm 15 should be correspondingly increased as can be understood from the relation between the size of the virtual source 25 and the size of the diaphragm 15 as explained in more detail above.
  • the size of the virtual source 25 may be maintained or even reduced, as follows from the expression of etendue as the product of the source area and solid angle.
  • the TIR lens portion 20" further comprises a plurality of legs in analogy with a lens holder 40 in order to position the central lens portion 20' at the desired distance from the light sensor 30.
  • the lens 20 of FIG. 7 may be positioned within the sensor device 10 in any suitable manner, e.g. using a separate lens holder 40 or in any other suitable manner.
  • FIG. 8 schematically depicts a cross-section of another embodiment of the sensor device 10 in which the sensor device 10 comprises a plurality of light sensors, which may be different light sensors, i.e. light sensors sensitive to different parts of the
  • the sensor device 10 may comprise at least two of a visible light sensor, a UV sensor, an IR sensor and so on.
  • a visible light sensor a UV sensor
  • an IR sensor a thermocouple
  • three different light sensors 30, 30' and 30" are shown by way of non-limiting example only.
  • Each of the light sensors is positioned on its respective optical axis opposite a respective aperture 15, 15' and 15", which apertures may be identical or may be different, e.g. have different diameters, depending on the optical requirements of the sensor device 10.
  • the respective light sensors 30, 30' and 30" preferably but not necessarily are mounted on a planar surface of the same carrier 50, e.g. a PCB, which has the advantage that the sensor arrangement may be manufactured or assembled in a straightforward manner without having to provide different carriers and mounting the different carriers within the housing of the sensor device 10.
  • each of the light sensors 30, 30', 30" may receive its incident light rays through a respective etendue-limited lens arrangement, e.g. respective etendue-limited lenses 20, 20' and 20", e.g. to image respective virtual sources onto the respective light sensors 30, 30', 30" as previously explained.
  • the respective etendue-limited lens arrangements may be mounted within the housing of the sensor device 10 in any suitable manner although preferably each of the respective etendue-limited lens arrangements, e.g. respective etendue-limited lenses 20, 20' and 20", are mounted in or form part of the respective lens holders as shown in FIG. 5 and 6 and described in more detail above, in which the respective lens holders may have legs of different heights, i.e.
  • the legs of the lens holder of the etendue-limited lens 20 have height H
  • the legs of the lens holder of the etendue-limited lens 20' have height FT
  • the legs of the lens holder of the etendue-limited lens 20" have height H"
  • H ⁇ H' ⁇ H with the respective heights been chosen such that the respective etendue-limited lens arrangements are correctly positioned relative to their respective light sensors 30, 30' and 30" as previously explained.
  • the legs of each lens holder may comprise a protrusion for mating with a corresponding recess in a carrier 50 of the associated light sensor, e.g. a single carrier 50 to facilitate straightforward positioning of the etendue-limited lens arrangements relative to the corresponding light sensors.
  • FIG. 9 schematically depicts an example embodiment of a lighting system 100 including a sensor device 10 according to one or more of the above described embodiments, a controller 1 10 and at least one lighting device 120.
  • the controller 1 10 is communicatively coupled to the sensor device 10 to receive sensor signals from the one or more light sensors in the sensor device 10.
  • the controller 1 10 is further communicatively coupled to the at least one lighting device 120 in order to control the luminous output of the at least one lighting device 120 in response to the received sensor signals from the sensor device 10.
  • the controller 1 10 may be any suitable controller, e.g. a dedicated microcontroller, a processor programmed to implement the desired control function, and so on.
  • the at least one lighting device 120 may be any suitable lighting device.
  • Lighting devices comprising one or more LEDs are particularly preferred as such lighting devices are energy-efficient, have a long lifetime and can adjust their luminous output particularly quickly in response to the reception of an altered control signal. This is particularly advantageous where the lighting system 100 is expected to retain a relatively constant level of illumination in a target area illuminated by the at least one lighting device 120, as the short response time of such LEDs-based lighting devices minimizes variations in the luminous intensity in the target area, e.g. variations caused by variations in ambient light levels illuminating the target area.
  • Such a lighting system 100 for instance may be designed as an indoor lighting system to provide appropriate illumination levels in work areas or other areas of interest.
  • appropriate illumination levels for example may be illumination levels meeting or exceeding a defined illumination threshold level or may be substantially constant
  • the lighting system 100 may be deployed such that the sensor device 10 is positioned relative to the target area such that light reflected by the target area, i.e. light rays having an angle of incidence not exceeding the acceptance angle of the appropriate light sensor in the sensor device 10, is captured by the appropriate light sensor in the sensor device 10.
  • reflected light may be ambient light in case the at least one lighting device 120 is switched off or a combination of ambient light and artificial light produced by at least one of the lighting devices 120 being switched on.
  • the sensor signal resulting from the detected reflected light levels may be processed by the controller 1 10 in order to generate one or more control signals for the at least one lighting device 120 to compensate for a fluctuation in a daylight contribution to a level of illumination in the target area.
  • the controller 1 10 may generate a control signal to increase a dimming level of one or more of the at least one lighting device 120 or switch off one or more of the at least one lighting device 120, whereas where the sensor device 10 detects an decrease in the levels of light reflected by the target area, the controller 1 10 may generate a control signal to reduce a dimming level of one or more of the at least one lighting device 120 or switch on one or more of the at least one lighting device 120.
  • Other suitable control mechanisms are well-known and will be immediately apparent to the skilled person.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Optics & Photonics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Photometry And Measurement Of Optical Pulse Characteristics (AREA)

Abstract

L'invention concerne un dispositif capteur (10) comprenant un logement (11) comprenant une ouverture (15) positionnée sur un axe optique (17) s'étendant à travers ladite ouverture; un capteur de lumière (30) disposé dans ledit boîtier et positionné sur l'axe optique, le capteur de lumière ayant une surface inférieure à celle de l'ouverture; et un agencement de lentille limité en étendue (20) entre l'ouverture et le capteur de lumière, l'agencement de lentille limité en étendue étant dimensionné pour rediriger la lumière exclusivement d'une source virtuelle (25) vers le capteur de lumière, la source virtuelle ayant un diamètre inférieur à celui de l'ouverture et étant positionnée sur l'axe optique entre l'ensemble lentille limité en étendue et l'ouverture de telle sorte que des rayons de lumière incidents (29) à travers l'ouverture sous un angle par rapport à l'axe optique dépassant un angle défini (Θ) ne peuvent pas traverser la source virtuelle. L'invention concerne également un système d'éclairage comprenant un tel dispositif capteur.
PCT/EP2016/079410 2015-12-08 2016-12-01 Dispositif capteur et système d'éclairage WO2017097659A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP15198319 2015-12-08
EP15198319.4 2015-12-08

Publications (1)

Publication Number Publication Date
WO2017097659A1 true WO2017097659A1 (fr) 2017-06-15

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4040751A (en) * 1976-01-13 1977-08-09 Polaroid Corporation Unicell photometer device
US4105300A (en) * 1977-01-31 1978-08-08 Polaroid Corporation Defocused unicell photometer with aspheric zone
US20040264004A1 (en) * 2003-05-05 2004-12-30 Illumitech Inc. Compact non-imaging light collector
EP1729102A2 (fr) * 2005-05-24 2006-12-06 Yonathan Gerlitz Détecteur avec optique miniature pour le recueil constant de l'énergie à partir de différentes distances
WO2008078253A2 (fr) * 2006-12-22 2008-07-03 Koninklijke Philips Electronics N.V. Dispositif de commande de sources de lumière
EP2117282A1 (fr) * 2007-01-10 2009-11-11 Panasonic Corporation Dispositif de cuisson a induction
US20140145069A1 (en) * 2012-11-28 2014-05-29 Intersil Americas LLC Packaged light detector semiconductor devices with non-imaging optics for ambient light and/or optical proxmity sensing, methods for manufacturing the same, and systems including the same

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4040751A (en) * 1976-01-13 1977-08-09 Polaroid Corporation Unicell photometer device
US4105300A (en) * 1977-01-31 1978-08-08 Polaroid Corporation Defocused unicell photometer with aspheric zone
US20040264004A1 (en) * 2003-05-05 2004-12-30 Illumitech Inc. Compact non-imaging light collector
EP1729102A2 (fr) * 2005-05-24 2006-12-06 Yonathan Gerlitz Détecteur avec optique miniature pour le recueil constant de l'énergie à partir de différentes distances
WO2008078253A2 (fr) * 2006-12-22 2008-07-03 Koninklijke Philips Electronics N.V. Dispositif de commande de sources de lumière
EP2117282A1 (fr) * 2007-01-10 2009-11-11 Panasonic Corporation Dispositif de cuisson a induction
US20140145069A1 (en) * 2012-11-28 2014-05-29 Intersil Americas LLC Packaged light detector semiconductor devices with non-imaging optics for ambient light and/or optical proxmity sensing, methods for manufacturing the same, and systems including the same

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