FR2740573A1 - PHOTOSENSITIVE DEVICE FOR THE INSTALLATION OF ROOM LIGHTING LEVEL CONTROLS - Google Patents

Abstract

The photosensor device comprises a photosensitive element (6) mounted on a base (7) with its sensitive surface facing upwards. The sensor is covered by a conical screen (8) forming an optical integrator. The optical transmission through the conical screen varies according to the angle at which light enters with respect to the vertical. A transmission mask (9) is applied to the outside surface of the cone, between two angles (theta-1, theta-2). This is intended to attenuate the sensitivity of the sensor when light is incident between two specified angles (aCmin, aCmax).

Description

1 2740573

  The subject of the invention is a photosensitive device

  for the installation of light level controls-

  ment of a room provided with at least one opening allows

  both the entry of natural light, this device being intended to be placed within easy reach of the user to deliver a quantity sufficiently representative of the overall level of brightness at

  inside the whole room.

  The patents FR 91 06 160 and FR 91 08 331 describe systems ensuring the management of light comfort inside a room comprising at least one opening allowing the entry of light and equipped with concealment means and / or artificial lighting. These means

  of occulation or lighting are electrically maneuverable

  only by means of a remote control device

  portable, usually placed on the work surface or

  on the bedside table. They include a light sensor

  thinness intended to transmit the state of the illumination to a logical processing unit which following the given illumination instruction will send orders by means

  of concealment and illumination for more or less illumination.

  These lighting management systems do not, however, take into account the fact that most of the concealment means have a non-diffusing effect. This translates, in direct sunlight conditions, into the appearance of violently lit areas30 and obscured areas. Such areas appear, for example, in the case of facade blinds, screens or Venetian blinds. The resulting effect in the room can, despite these shadows and violent lighting, be considered satisfactory from the point of view of

  the occupant, the latter being more sensitive to the overall level of illumination than to its spatial distribution.

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  Given its small dimensions, the sensor will be, in such a situation, either in an area

  brightly lit directly, either in a uni-

  enlightened by diffusion of all the sur-

  faces. The illumination of a directly lit surface

  by the sun being several hundred times greater than

  higher than the illumination of the same surface subjected to the luminance of the other surfaces of the room, an elementary sensor will give extremely different values in the two locations a few centimeters apart while the overall level of illumination is

the same.

  In the case of an operation of a facade blind, a shadow can move and reach the sensor while the measurement given by the latter of too much light will have caused a closing command. The sensor is then suddenly subjected to a very strong reduction in brightness, which logically leads to an opening operation. An oscillating movement

  the concealment means is therefore difficult to avoid.

  The solution, which so far has been given to this pro-

  problem, is to place the light sensors on the ceiling of the premises so that they are not

  reached by direct sunlight. However, it is legal

  heavens to associate the light sensor with the means

  of the concealment means which must

  be accessible by the occupant. It is also advantageous for the sensor to be sensitive to the level of illumination close to the user: its plane of

work, his bedside table.

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  The problem to be solved thus posed, in particular in its contradictory aspects, the aim of the invention is to produce a sensor of small dimensions allowing

to provide a practical solution.

  This object is achieved by the photosensitive device

  lon the invention characterized in that it comprises at

  minus a photosensitive element associated with an op-

  weighted integrating tick with attenuated sensitivity in a range between two values of conical angles aCmin and aCmax such that aCmin is less than aSmin and that aCmax is greater than caSmax, aC representing the conical angle of a cone with vertex l photosensitive element and the spherical angles aSmin and aSmax representing the limits of the portion of sphere, centered on the photosensitive element, in

  which the photosensitive element can be illuminated di-

directly by the sun.

  Because the weighted optical system has an attenuated sensitivity in the areas where the sensor is likely to be directly lit by the sun, the luminance of the direct sun rays perceived by the sensor is much lower. The sensor is therefore less sensitive to direct sunlight and reacts

  exclusively at the overall level of illumination.

  Preferably, the integrating optical system is made of injected material and the photosensitive element is embedded in the material of the system

integrative optics.

  The invention will be explained more explicitly with the aid of exemplary embodiments represented in the appended drawings, in which: FIGS. 1 and 2 represent the different

  effects of direct solar radiation to which a collector placed on a work surface in a room lit by a bay is subjected.

  Figures 3 to 6 are schematic representations

  the volume of use of a device according to the invention-10 tion in different premises subject to different effects of direct solar radiation.

  Figure 7 illustrates the description of the device according to

  the invention.15 Figures 7a, 7b and 7c are diagrams

  representing different laws of sensitivities in the light of a device according to the invention.

  Figure 8 is a schematic view of a first embodiment of the device according to the invention.

  Figure 9 is a schematic view of a second embodiment of the device according to the invention.25 Figure 10 is a schematic view of a third

  embodiment of the device according to the invention.

  Figure 11 is a schematic view of a fourth

  embodiment of the device according to the invention.

  Figure 12 is a schematic view of a fifth

  embodiment of the device according to the invention.

  Figure 13 is a schematic view of a variant of the fifth embodiment of the device according to the invention.

  In the following description all the angle values

  for which nothing is specified are given with respect to the vertical. Figures 1 and 2 show a room 1 in which

  a photosensitive device 2 is placed on a table 10 3.

  The device 2 can perceive direct lighting of the

  sun between an angle aSl and an angle aS2 determined either by the heights HB min and HB max of the bay15 (figure 1), or by the extreme values of the solar height (figure 2) or the combination of the two.

  These angles aSl and aS2 are bounded by angles aSmin and aSmax, aSmin designating the extreme value of closing the angle aS1 and aSmax designating the extreme value of opening the angle aS2 when the element

  photosensitive is moved inside the room.

  Depending on the room, the volume of use of the device according to the invention is different. This volume is such that in each of its points aSmin remains greater than

  aCmin and aSmax remains lower than aCmax.

  In figures 3 and 4, this volume of use is determined for a weighted integrating optical system whose surface with attenuated sensitivity is delimited by the angles aCmin = 20 and aCmax = 80 and for a sun whose rays can be perceived between 0 and 90. To determine the volume of use of the device, it is sufficient to draw, on the vertical section of the room, a straight line 4 of inclination aCmin with respect to the vertical and pressing against the upper part of the bay and a straight line 5 of inclination cCmax with respect to the vertical and pressing against the5 lower part of the bay. If the device is located to the left of line 4 or above line 5, rays of sunshine directly illuminate a part of the surface of the device whose sensitivity is not attenuated. These two lines therefore determine the volume in which a given device can be used. A device with the values aCmin and aCmax

  cited above has a fairly low volume of use Vi in the room of FIG. 3. On the other hand, in the room according to FIG. 4, this volume15 of use V1 is already greater.

  In fact, the zenith height of the sun is determined by the latitude of the place and in the majority of cases (urban or hilly area), the height of the sun on the horizon-is greater than 200. For a device with the same characteristics of angles than that of Figures 3

  and 4, the configuration of the room and its bays will therefore no longer matter in such places as to the risk for the sensor to be lit by the sun at the zenith25 or on the horizon.

  In FIG. 5, the volume of use of a device having these same characteristics is shown for a room of the same type as that of FIG. 330 but situated at a latitude such that the sun at noon always remains at more than 20 of the vertical and in a

  environment such as the sun never appears less than 20 above the horizon. In such a case, the device can be placed anywhere in the room.

  In Figure 6, the volume of use of the same device

  is represented for the same type of local, under the same environmental conditions, but at a latitude closer to the equator, such that the sun can be less than 20 from the vertical. The volume of use V2 is in this case limited.

  The device according to the invention must best satisfy the following compromise: 10 - present a narrow attenuated sensitivity zone so that the photosensitive element provides information as representative as possible of the overall illumination of the room, at the risk of limiting the volume in which the device can be used without risk of direct exposure of the photosensitive element

to solar radiation.

  - present a fairly wide attenuated sensitivity area so that the device can be placed at any point in the room, without the risk of direct exposure of the photosensitive element to solar radiation. FIG. 7 schematically represents a sensor satisfying the above conditions. This sensor comprises a photosensitive element 6, placed on a base 7 containing the electronics of the sensor, associated with a weighted integrating optical system 8. This sensor has an attenuated sensitivity in a range 9 between two values of angles Qi and 02. 01 (respectively 02) is chosen according to the optical characteristics of the weighted integrator system 8 and the conical angle cCmax (respectively

aCmin) wanted.

  The integrator's sensitivity law can present

  a sudden change, as shown in Figure 7a.

  The sensitivity can be, for example, equal to 0.01 for the surfaces lying between the conical angles aCmin and aCmax and equal to 1 for the remaining surfaces. The sensitivity law can also have a gradually varying profile as shown in FIG. 7b and have a more or less pronounced slope when passing from the sensitive zone of the device to the less sensitive zone.

  The luminance of the rising / setting sun being weaker

  ble than that of the zenithal sun, the slope in the vicinity of the conical angle aCmax may be less pronounced than that in the vicinity of the angle aCmin as this is

shown in Figure 7c.

  Between 0 and aCmin the sensitivity will be normal to allow the integration of the illumination, for example from the ceiling, just as between aCmax and a chosen angle of 120, to allow the integration of the illumination,

  for example, the worktop and the floor.

  This angle of 120 can be changed, depending on the opening

of the normal integration zone.

  FIGS. 8 to 11 represent several preferred embodiments of the method according to the invention, in which a value of 20 is assigned to the angle aCmin and a value of 80 to the angle caCmax, these values corresponding to a compromise for an urban premises of

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  industrialized country at latitude 45.

  The different embodiments of the device according to the invention shown have sensitivity curves as a function of the different angle of illumination due to their different geometric shape, the sensitivity of certain angular sectors can also be modified by depositing an attenuating mask. 10 For the sake of clarity of the figures, the connection between

  the photosensitive element and its electronics have not been shown.

  FIG. 8 schematically represents a first embodiment of the device according to the invention. This device comprises a photosensitive element 10 on its upper horizontal face and its lower horizontal face. This photosensitive element 10 is placed in the center of a spherical integrating optical system 11 resting on a base 12 containing the electronics of the

  device. A transmission mask 13 is affixed to the surface of the integrating optical system between the conical angles 03 and 64. In this particular embodiment, the angle 03 (respectively 84) is merged with the angle aCmin (respectively aCmax).

  The light rays of angle between 0 and aCmin and between aCmax and 120 reach directly the photosensitive element 10 after diffraction during penetration into the integrating optical system 11. The light rays inciting with an angle between aCmin and aCmax also after diffraction with the photosensitive element, but with intensity

  greatly reduced due to the transmission mask 13.

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  FIG. 9 schematically represents a second embodiment of the device according to the invention. This device comprises a photosensitive element 14 on its upper horizontal face and its lower horizontal face5 and located at the center of an integrating optical system 15 in the form of an ellipsoid, resting on a base 16 containing the electronics of the device. This optical system 15 is covered with a transmission mask 17 between the conical angles 35 and 06. As in the previous embodiment, the light rays of angle between 0 and aCmin and between aCmax and 120 reach directly at the photosensitive element 14 after diffraction upon penetration into the integrating optical system 15. Those inciding with an angle between aCmin and aCmax are

  first attenuated in their intensity by the transmission mask 17.

  A third embodiment of the device according to the invention is shown diagrammatically in FIG. 10. This device comprises a photosensitive element 18 on its two upper and lower horizontal faces, located at the center of an integrating optical system 19 fixed to a base 20 containing the electronics of the device. The optical system 19 consists of two ellipsoidal parts 19a, 19b symmetrical with respect to the horizontal plane passing through the photosensitive element 18 and connected together by a cylindrical part 19c. The upper ellipsoidal part 19a is covered between the conical angles

  97 and 98 of a transmission mask 21.

  The light rays of angle between 0 and Cmin and il 2740573 between aCmax and 120 reach the element directly

  photosensitive 18 after diffraction upon penetration into the optical device. Those of angle between aCmin and oCmax are attenuated in their intensity when passing through the transmission mask 21.

  FIG. 11 represents a fourth embodiment of the device according to the invention. The device here comprises a photosensitive element 22 on its upper horizontal face and an integrating optical system 23

  resting on a base 24 containing the electronics of the device.

  This integrating optical device 23 has an outer surface and an inner surface of different shapes, symmetrical with respect to a vertical axis. The upper part 23a of its outer surface has the form of a hearth paraboloid F1 extended by a vertical cylindrical part 23b, itself extended by a toric part 23c. This toric part is formed by the revolution of a circle of center F2 around the vertical axis of symmetry of the

system 23.

  The inner surface has a hemispherical upper part with center F1 23d extended by a ring 23e formed by the revolution of a focal point dish F2 around the vertical axis of symmetry of the optical system 23. It is dimensioned in such a way that it is located above the hearth F1 of the paraboloid 23a.

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  The O-ring part 23c of the outer surface and the ring 23e of the inner surface meet on

the base 24.

  The photosensitive element 22 is located at the focus F1 of the

dish 23a.

  A transmission mask 25 is affixed to the paraboloid 23a between the conical angle 09 and the edge of the paraboloid and to the cylindrical part 23b of the

  outer surface of the integrating optical system 23.

  A transmission mask 26 is affixed to the interior surface of the integrating optical system on the ring

23rd.

  The light rays of angle between 0 and aCmin reach the photosensitive element 22 directly after diffraction when penetrating into the

integrating optical system 23.

  The light rays of angle between aCmax and 120 reach the photosensitive element 22 after two reflections, one on the reflecting surface formed by the ring 23e of the interior surface of the optical system 23 and the other on the surface reflective formed by the part of the paraboloid 23a covered with a transmission mask 25 along trajectories

  between trajectories 27 and 28.

  Figure 12 shows a fifth embodiment of the device of the invention. This device comprises a photosensitive element 29 and an integrating optical system 30 fixed on a base 31. The optical system 30 is symmetrical with respect to a vertical axis passing through the center of the photosensitive element. It comprises an upper part of conical or pyramidal shape extended by a convex ring fixed at its base to the base 31 and is made of diffusing plastic. A transmission mask 32 is applied to the outside of the integrating optical system

  between the conical angles 810 and 811.

  A variant of the embodiment of Figure 12 is shown in Figure 13. This variant comprises a photosensitive element 33, a weighted integrating optical system 34 and a base 35 similar to those of the previous embodiment. It further comprises a transmission mask 36 placed inside the optical system 34 around the photosensitive element 33. This mask 36 is intended to attenuate the intensity of the incident light rays with an angle between the horizontal and the conical angle 812. It has a cylindrical shape of axis the axis of symmetry of the optical system 34, a circular section if the optical system has a conical shape, or square if the optical system 34 has a pyramidal shape. The optical system 34 is further provided on its inner surface with a reflecting plate 37 arranged in such a way that the light rays inciting with an angle greater than

  013 are focused towards the photosensitive element 33.

  According to the characteristics of the place where the device according to the invention is intended to be used, the transmission mask can have a transmission coefficient

zero or nonzero.

Claims (10)

  1. Photosensitive device for installation for controlling the level of illumination of a room provided with at least one opening allowing the entry of natural light, this device being intended to be placed at the place to be lit to deliver a quantity representative of the lighting at this location, characterized in that it comprises at least one photosensitive element (10; 14; 18; 22) associated with a weighted integrating optical system (11; 15; 19; 23) having a sensitivity attenuated in a range between two conical angle values aCmin and aCmax such that aCmin is less than aSmin and that aCmax is greater than aSmax, aC representing the conical angle of a cone with the photosensitive element and the angles at the top spherical aSmin and aSmax representing the limits of the portion of sphere, centered on the photosensitive element, in which the photosensitive element can be directly lit by the sun.   2. Device according to claim 1, characterized in that it comprises a photosensitive element (10) on its upper and lower horizontal faces, arranged in the center of an integrating optical system (11) in the form of a sphere resting on a base ( 12) containing the electronics of the device and that a transmission mask (13) is affixed to the exterior surface of the integrating optical system (11) between two angles conical 83 and 04.   3. Device according to claim 1, characterized in that it comprises a photosensitive element (14) on its upper and lower horizontal faces, disposed in the center of an integrating optical system (15) in the form of an ellipsoid resting on a base. (15) containing the electronics of the device and that a transmission mask (17) is affixed to the exterior surface of the integrating optical system (15) between two conical angles 05 and 06. 4. Device according to claim 1, characterized in that it comprises an element (18) photosensitive on its upper and lower horizontal faces, located in the center of an integrating optical system (19) fixed to a base (20) containing l electronics of the device, and consisting of two ellipsoidal parts (19a, 19b) symmetrical with respect to the horizontal plane passing through the photosensitive element (18) and connected together by a cylindrical part (19c), and that the upper ellipsoidal part ( 19a) is covered between the   angles 07, 08 of a transmission mask (21).   5. Device according to claim 1, characterized in that it comprises a photosensitive element (22) on its upper horizontal face and an integrating optical system (23) symmetrical with respect to a vertical axis and resting on a base (24) containing the electronics of the device, the upper part (23a) of the external surface of the optical system (23) having the form of a paraboloid of focus F1, this paraboloid (23a) being extended by a cylindrical part (23b), even extended by a toric part (23c) formed by the revolution of a circle of center F2 around the vertical axis of symmetry of the optical system (23), the inner surface of the optical system (23) having an upper part (23d ) hemispherical center F1 extended by a ring (23e) formed by the revolution of a focal point dish F2 around the vertical axis of symmetry of the optical system (23), the toric part (23c) of the external surface and l '' ring (23rd) of the inner surface joining on the base (24), that a transmission mask5 (25) reflecting is affixed on the paraboloide (23a) between an angle 09 and the edge of the   paraboloid and on the cylindrical part (23b) of the exterior surface of the optical system (23) and that a reflecting transmission mask (26) is affixed to the ring (23e) of the interior surface of the optical system (23).   6. Device according to claim 1, characterized in that it comprises a photosensitive element (29; 33) fixed on a base (31; 35) and an integrating optical system (30; 34) symmetrical with respect to a passing vertical axis through the center of the photosensitive element, that the integrating optical system has a conical or pyramidal shape in its upper part 20 and that this conical or pyramidal part is extended by a convex ring fixed at its base on the base (31;). 7. Device according to claim 6, characterized in that a transmission mask (32) is arranged outside the integrating optical system (30) between the conical angles 910 and 011.   8. Device according to claim 6, characterized in that a transmission mask (36) is placed inside the integrating optical system (34) around the photosensitive element (33), this transmission mask (36) being dimensioned so as to attenuate the intensity of the incident light rays with an angle between 012 and the horizontal after their passage through the optical system (34) and that a plate   reflecting (37) intended to focus towards the photosensitive element the light rays of incidence greater than a conical angle 013 is arranged on the interior surface of the integrating optical system (34).   9. Device according to one of claims 2 to 4, characterized in that the integrating optical system   weighted (11; 15; 19) is made of injected material and that the photosensitive element (10; 14; 18) is embedded in the material of the optical system (11; 15; 19).   10. Device according to one of claims 6 to 8, characterized in that the optical system is made of material diffusing plastic.