CIRCADIAN LIGHTING FOR MODERATE LIGHT LEVELS

Abstract

The invention provides a light generating system (1000) comprising (i) a light generating device (100) configured to generate device light (101) having a controllable radiant flux and a controllable spectral power distribution, and (ii) a control system (300) configured to control the radiant flux and the spectral power distribution of the device light (101); wherein: (A) a ratio B/Y of the device light (101) is defined as a ratio of a radiant flux of the device light (101) in the 450-500 nm wavelength range and of a radiant flux of the device light (101) in the 550-600 nm wavelength range; (B) in a first operational mode of the light generating system (1000) the control system (300) is configured to change from a first device light setting to a second device light setting, different from the first device light setting; (C) the first device light setting and the second device light setting are selected from: (a) a high radiant flux first setting (S.sub.1) wherein the device light (101) is first light with a first radiant flux I.sub.1 and a first B/Y ratio R.sub.1; and (b) a low radiant flux second setting (S.sub.2) wherein the device light (101) is second light with a second radiant flux I.sub.2 and a second B/Y ratio R.sub.2; and (D) I.sub.2<I.sub.1, and R.sub.1<R.sub.2.

Claims

1. A light generating system comprising a light generating device configured to generate device light having a controllable radiant flux and a controllable spectral power distribution, and a control system configured to control the radiant flux and the spectral power distribution of the device light; wherein: a ratio B/Y of the device light is defined as a ratio of a radiant flux of the device light in the 450-500 nm wavelength range and of a radiant flux of the device light in the 550-600 nm wavelength range; in a first operational mode of the light generating system the control system is configured to change from a first device light setting to a second device light setting, different from the first device light setting; the first device light setting and the second device light setting are selected from: (a) a high radiant flux first setting wherein the device light is first light with a first radiant flux I.sub.1 and a first B/Y ratio R.sub.1; and (b) a low radiant flux second setting wherein the device light is second light with a second radiant flux I.sub.2 and a second B/Y ratio R.sub.2; I.sub.2<I.sub.1, and R.sub.1<R.sub.2; in a second operational mode of light generating system the control system is further configured to change from a third device light setting to a fourth device light setting, different from the third device light setting; the third device light setting and the fourth device light setting are selected from: (a) a high radiant flux third setting wherein the device light is third light with a third radiant flux I.sub.3 and a third B/Y ratio R.sub.3; and (b) a low radiant flux fourth setting wherein the device light is fourth light with a fourth radiant flux I.sub.3 and a fourth B/Y ratio R.sub.3; and I.sub.4<I.sub.3, and R.sub.3>R.sub.4.

2. The light generating system according to claim 1, wherein the light generating device is able to generate device light with a maximum radiant flux I.sub.max, wherein I.sub.10.1*I.sub.max and I.sub.20.9*I.sub.max, and wherein I.sub.2/I.sub.10.9.

3. The light generating system according to claim 1, wherein R.sub.20.25 and wherein R.sub.1<0.25.

4. The light generating system according to claim 1, wherein the light generating device is configured to provide in the low radiant flux second setting a beam of device light having a maximum luminous intensity selected from the range of 12-220,000 candela; and wherein the device light in the first device light setting and the second device light setting is white light.

5. The light generating system according to claim 1, wherein R.sub.40.41 and wherein R.sub.30.25.

6. The light generating system according to claim 1, wherein the light generating device is able to generate device light with a maximum radiant flux I.sub.max, wherein I.sub.30.1*I.sub.max and I.sub.40.9*I.sub.max, and wherein I.sub.4/I.sub.30.9; and wherein R.sub.30.25 and wherein R.sub.4<0.25.

7. The light generating system according to claim 1, wherein the light generating device is configured to provide in the low radiant flux fourth setting a beam of device light having a maximum luminous intensity selected from the range of 12-220,000 candela.

8. The light generating system according to claim 1, wherein: in a third operational mode of light generating system the control system is configured to change from the third device light setting to the second device light setting, different from the third device light setting; the third device light setting and the first device light setting are selected from: (a) the high radiant flux setting wherein the device light is third light with the third radiant flux I.sub.3 and the third B/Y ratio R.sub.3; and (b)) the low radiant flux second setting wherein the device light is second light with the second radiant flux I.sub.2 and the second B/Y ratio R.sub.2 according to claim 1; and I.sub.2<I.sub.3, and 0.5R.sub.3/R.sub.20.95.

9. The light generating system according to claim 8, wherein the light generating device is able to generate device light with a maximum radiant flux I.sub.max, wherein I.sub.30.1*I.sub.max and I.sub.20.9*I.sub.max, and wherein I.sub.2/I.sub.30.9.

10. The light generating system according to claim 8, wherein R.sub.20.25.

11. The light generating system according to claim 1, comprising one or more first light sources configured to generate first white light, wherein the first light has a first x color coordinate x.sub.1, and one or more second light sources configured to generate second white light, wherein the second light has a second x color coordinate x.sub.2, wherein x.sub.10.35, wherein the color coordinates are according to CIE 1931, wherein x.sub.20.4, wherein x.sub.1x.sub.20.03, wherein the one or more first light sources together may have a first maximum electrical power W1, wherein the one or more second light sources together may have a second maximum electrical power W2, and wherein 2W1/W2100.

12. The light generating system according to claim 1, wherein the light generating system comprises a parking garage lighting device, a quay lighting device a dock lighting device, road lighting device, a street lighting device, a park lighting device, a square lighting device, an emergency lighting device, a tunnel lighting device, an area lighting device, an office lighting device, an industry lighting devices, a residential lighting device, a hospital lighting device, a patient room lighting device, a retail lighting device, a warehouse lighting device, a stable lighting device, and an animal holding lighting device.

13. A method for controlling a controllable radiant flux and a controllable spectral power distribution of device light wherein: a ratio B/Y of the device light is defined as a ratio of a radiant flux of the device light in the 450-500 nm wavelength range and of a radiant flux of the device light in the 550-600 nm wavelength range; the method comprises changing from a first device light setting to a second device light setting, different from the first device light setting; the first device light setting and the second device light setting are selected from: (a) a high radiant flux first setting wherein the device light is first light with a first radiant flux I.sub.1 and a first B/Y ratio R.sub.1; and (b) a low radiant flux second setting wherein the device light is second light with a second radiant flux I.sub.2 and a second B/Y ratio R.sub.2; I.sub.2<I.sub.1, and R.sub.1<R.sub.2; the method further comprising: changing from a third device light setting to a fourth device light setting, different from the third device light setting; the third device light setting and the fourth device light setting are selected from: (a) a high radiant flux third setting wherein the device light is third light with a third radiant flux I.sub.3 and a third B/Y ratio R.sub.3; and (b) a low radiant flux fourth setting wherein the device light is fourth light with a fourth radiant flux I.sub.3 and a fourth B/Y ratio R.sub.3; and I.sub.4<I.sub.3, and R.sub.3>R.sub.4.

14. The method according to claim 13, the method further comprising: changing from the third device light setting to the second device light setting, different from the third device light setting; the third device light setting and the first device light setting are selected from: (a) the high radiant flux setting wherein the device light is third light with the third radiant flux I.sub.3 and the third B/Y ratio R.sub.3; and (b) the low radiant flux second setting wherein the device light is second light with the second radiant flux I.sub.2 and the second B/Y ratio R.sub.2 according to any one of the preceding claims; and I.sub.2<I.sub.3, and 0.5R.sub.2/R.sub.30.95.

15. A light generating device selected from the group of a lamp, a luminaire, a projector device, a disinfection device, and an optical wireless communication device, comprising the light generating system according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0139] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

[0140] FIGS. 1a-1c schematically depicts some aspects;

[0141] FIG. 2 schematically depicts dimming regions and the effect on melatonin; and

[0142] FIG. 3 schematically depict some (application) embodiments. The schematic drawings are not necessarily to scale.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0143] FIG. 1a schematically depicts an embodiment of a light generating system 1000 comprising (i) a light generating device 100 configured to generate device light 101 having a controllable radiant flux and a controllable spectral power distribution, and (ii) a control system 300 configured to control the radiant flux and the spectral power distribution of the device light 101. Especially, a ratio B/Y of the device light 101 is defined as a ratio of a radiant flux of the device light 101 in the 450-500 nm wavelength range and of a radiant flux of the device light (101) in the 550-600 nm wavelength range. In embodiments, in a first operational mode of the light generating system 1000 the control system 300 is configured to change from a first device light setting to a second device light setting, different from the first device light setting. Further, in embodiments the first device light setting and the second device light setting are selected from: (a) a high radiant flux first setting S.sub.1 wherein the device light 101 is first light with a first radiant flux I.sub.1 and a first B/Y ratio R.sub.1; and (b) a low radiant flux second setting S.sub.2 wherein the device light 101 is second light with a second radiant flux I.sub.2 and a second B/Y ratio R.sub.2. Especially in embodiments I.sub.2<I.sub.1. Further, especially in embodiments R.sub.1<R.sub.2. I.sub.1 and I.sub.2 may be on energy scales, like in Watts.

[0144] In specific embodiments, the light generating device 100 is able to generate device light 101 with a maximum radiant flux I.sub.max, wherein I.sub.10.1*I.sub.max and I.sub.20.9*I.sub.max, and wherein I.sub.2/I.sub.10.9.

[0145] Further, in specific embodiments R.sub.22.

[0146] In embodiments, the control system 300 is configured to control the change from the first device light setting to the second device light setting in dependence of one or more of an input signal of a user interface, a sensor signal, and a timer, wherein the change is a gradual change over a change time, in embodiments selected from the range of 15-120 minutes.

[0147] In further embodiments, in a second operational mode of light generating system 1000 the control system 300 is configured to change from a third device light setting to a fourth device light setting, different from the third device light setting. Especially, in embodiments the third device light setting and the fourth device light setting are selected from: (a) a high radiant flux third setting S.sub.3 wherein the device light 101 is third light with a third radiant flux I.sub.3 and a third B/Y ratio R.sub.3; and (b) a low radiant flux fourth setting S.sub.4 wherein the device light 101 is fourth light with a fourth radiant flux I.sub.3 and a fourth B/Y ratio R.sub.3. Especially, in embodiments I.sub.4<I.sub.3. Further, in specific embodiments R.sub.3>R.sub.4.

[0148] Especially, in embodiments the light generating device 100 is able to generate device light 101 with a maximum radiant flux I.sub.max. Especially in embodiments I.sub.30.1*I.sub.max and I.sub.40.9*I.sub.max. Further, in specific embodiments I.sub.4/I.sub.30.9. Yet further, in embodiments the third light has a third correlated color temperature T.sub.C3, wherein the fourth light has a fourth correlated color temperature T.sub.C4, wherein in specific embodiments T.sub.C34000K, T.sub.C43000 K.

[0149] Yet further, in specific embodiments the control system 300 is configured to control the change from the third device light setting to the fourth device light setting in dependence of one or more of an input signal of a user interface, a sensor signal, and a timer, wherein the change is a gradual change over a change time selected from the range of 15-120 minutes.

[0150] Also in embodiments, in a third operational mode of light generating system 1000 the control system 300 is configured to change from the third device light setting to the second device light setting, different from the third device light setting. Especially, in embodiments the third device light setting and the first device light setting are selected from: (a) the high radiant flux setting S.sub.3 wherein the device light 101 is third light with the third radiant flux I.sub.3 and the third B/Y ratio R.sub.3; and (b) the low radiant flux second setting S.sub.2 wherein the device light 101 is second light with the second radiant flux I.sub.2 and the second B/Y ratio R.sub.2 claims. Further, in embodiments I.sub.2<I.sub.3. Especially, in embodiments 0.5R.sub.2/R.sub.30.95.

[0151] Yet further, in embodiments the light generating device 100 is able to generate device light 101 with a maximum radiant flux I.sub.max, wherein I.sub.30.1*I.sub.max and I.sub.20.9*I.sub.max, and wherein I.sub.2/I.sub.30.9.

[0152] Yet further, in embodiments the control system 300 is configured to control the change from the third device light setting to the second device light setting in dependence of one or more of an input signal of a user interface, a sensor signal, and a timer, wherein the change is a gradual change over a change time selected from the range of 15-120 minutes.

[0153] Hence, the invention also provides a method for controlling a controllable radiant flux and a controllable spectral power distribution of device light 101 wherein: (a) a ratio B/Y of the device light 101 is defined as a ratio of a radiant flux of the device light 101 in the 450-500 nm wavelength range and of a radiant flux of the device light (101) in the 550-600 nm wavelength range; (b) the method comprises changing (in a first operational mode) from a first device light setting to a second device light setting, different from the first device light setting; (c) the first device light setting and the second device light setting are selected from: (i) a high radiant flux first setting S.sub.1 wherein the device light 101 is first light with a first radiant flux I.sub.1 and a first B/Y ratio R.sub.1; and (ii) a low radiant flux second setting S.sub.2 wherein the device light 101 is second light with a second radiant flux I.sub.2 and a second B/Y ratio R.sub.2. Especially, in embodiments I.sub.2<I.sub.1. Further, in embodiments R.sub.1<R.sub.2.

[0154] In specific embodiments, the control system 300 is configured to control the change from the third device light setting to the fourth device light setting in dependence of one or more of an input signal of a user interface, a sensor signal, and a timer, wherein the change is a gradual change over a change time selected from the range of 15-120 minutes.

[0155] The method comprises changing in a second operational mode from a third device light setting to a fourth device light setting, different from the third device light setting. The third device light setting and the fourth device light setting are selected from: (a) a high radiant flux third setting S.sub.3 wherein the device light 101 is third light with a third radiant flux I.sub.3 and a third B/Y ratio R.sub.3; and (b) a low radiant flux fourth setting S.sub.4 wherein the device light 101 is fourth light with a fourth radiant flux I.sub.3 and a fourth B/Y ratio R.sub.3, wherein I.sub.4<I.sub.3 and wherein R.sub.3>R.sub.4.

[0156] Yet further, in specific embodiments the method comprises changing (in a third operational mode) from the third device light setting to the second device light setting, different from the third device light setting. Especially, in embodiments the third device light setting and the first device light setting are selected from: (a) the high radiant flux setting S.sub.3 wherein the device light 101 is third light with the third radiant flux I.sub.3 and the third B/Y ratio R.sub.3; and (b) the low radiant flux second setting S.sub.2 wherein the device light 101 is second light with the second radiant flux I.sub.2 and the second B/Y ratio R.sub.2 according to any one of the preceding claims. Especially, in embodiments I.sub.3<I.sub.2. Further, in specific embodiments 0.5R.sub.2/R.sub.30.95.

[0157] Referring to FIG. 1b, four possible states are indicated, wherein the column NA indicates non-active states and column MS indicate melatonin suppression states (or active states). References IL and IH indicate a low radiant flux light level and high radiant flux light level, respectively. References (1), (2), (3), and (4) indicate the first operational mode, the second operational mode, the third operational mode, and the fourth operational mode, respectively. References 5 and 6, indicate other operational modes, wherein an S2-S4 or S1-S3 transition may take place, respectively.

[0158] Referring to FIG. 1c, schematically some possible changes in intensity between a low radiant flux state and a high radiant flux state are depicted. Note that other changes may also be possible, like an abrupt change. On the y-axis the B/Y ratios (or R value) is indicated, and on the x-axis the intensity, between 0% and 100%.

[0159] FIG. 2 schematically depicts a graph similar to the table of FIG. 1b. On the y-axis, R values are indicated, and exemplary possible correlated color temperature are added as well. On the x-axis the lux on the human eye are indicated, between about 0.05-5000 lux. References S and NS indicated melatonin suppression and no melatonin suppression, respectively. Reference a schematically depicts road light dimming. Reference b indicates home light dimming or patient room dimming, and reference c indicates another example of patient dimming. For instance, in one situation one may not want to disturb the patient sleep but provide for a good visual inspection; while in another situation one may want to promote falling asleep or waking up. Reference d indicates an example of a work-sleep transition. Reference RD indicates regular dimming and reference WD indicates warm dimming. Regular dimming may especially imply that the CCT remains essentially constant while the flux changes and warm dimming may especially imply that the CCT decreases with decreasing flux.

[0160] FIG. 3 schematically depicts some embodiments of such light generating systems, such as light generating devices 1200 selected from the group of a lamp 1, a luminaire 2, a projector device 3, a disinfection device, and an optical wireless communication device, comprising the light generating system 1000 as defined herein. FIG. 3 schematically depicts an embodiment of a luminaire 2 comprising the light generating system 1000 as described above. Reference 301 indicates a user interface which may be functionally coupled with the control system 300 comprised by or functionally coupled to the light generating system 1000. FIG. 3 also schematically depicts an embodiment of lamp 1 comprising the light generating system 1000. Reference 3 indicates a projector device or projector system, which may be used to project images, such as at a wall, which may also comprise the light generating system 1000.

[0161] Referring to FIG. 1a and FIG. 3, the invention may also provide a stationary system, like a system essentially having no controllability of the spectral power distribution (and/or a system having essentially no controllability of the intensity). In aspects, the invention also provides a light generating system 1000 comprising a light generating device 100 configured to provide a beam 115 of device light 101, wherein: (a) the beam 115 of device light 101 has an optical axis O; (b) the light generating system 1000 is configured to provide device light 101 with a intensity selected from the range of 12-220,000 candela on a surface 9 perpendicular to the optical axis at a first distance d1 from the device 100, wherein d1 is 1 m, wherein the device light 101; (c) a ratio B/Y of the device light 101 is defined as a ratio of a radiant flux of the device light 101 in the 450-500 nm wavelength range and of a radiant flux of the device light (101) in the 550-600 nm wavelength range is at least 2. In an Example, a road lighting luminaire, with 2000 lumen at 2300 K, B/Y=0.192 is used. The value of E.sub.eye may be below 30 lux. In early evening rush hour (first hours and last hours of lighted period) alertness matters for road users, a value of B/Y<0.25 may be chosen, which may be achieved using 10 white LEDs (2200 K) powered at a total of 9.75 W.sub.el, producing 6.23 W.sub.opt. During quiet hours of the night: less disturbance of residents and occasional road users, the value of B/Y>0.25, and dimming to 25% of nominal level. The same 10 white LEDs powered at 2.25 W.sub.el, and one additional blue (450 nm) LED, powered with 1.0 W.sub.el, together producing 500 lm (2.20 W.sub.opt) at 3800 K, and a value of B/Y=1.68 may be chosen. To achieve the required shift in B/Y, a ratio of the installed power of the two LED colors in the range e.g. 1%P.sub.Blue/P.sub.White45% may be required.

[0162] In an example, in a living room, during the evening one may desire to study, where 200 lux E.sub.h may be needed for visual performance and comfort, and 100 lux E.sub.eye, 2350 K white light, using 5 W LED lamps, producing 1100 lm, R=0.227 (not suppressing). However, when later at early night, and relaxation is desired (after studying, before going to sleep, no suppression desired) the light may be dimmed to 20 lux E.sub.eye (20%), and adding 0.23 W.sub.el of 6500 K white LED light, to get a flux of 220 lm, of 2850 K, and a value of R=0.49.

[0163] In the above example, many people find 2350 K more uncomfortable (more fatiguing) for high spatial resolution visual tasks (e.g. reading, needle work) compared to higher CCTs. An option is to set illuminance for visually demanding tasks to just below threshold (e.g. E.sub.eye=20 lux, but choose higher CCT and/or R value (e.g. 4200 K, R=1.65). Later in the evening, a cozier atmosphere can be created by changing to a lower CCT (e.g. 2400 K (R can be about 0.23)) but to prevent melatonin suppression, the light level may be slightly increased (the opposite of warm dimming) e.g. to 40 lux E.sub.eye. The high light level can be made using LEDs of 2400 K (9.5 W.sub.el, 2000 lm, R=0.246), dimming these to 48% and adding 1.9 W.sub.el (1.33 W.sub.opt) of 450 nm blue LED, gives a flux of 1000 lm, R=1.65 (CCT=4200 K).

[0164] In an example, in outdoor sports/area/workplace lighting, during hours of high activity (or sports training/match) 100 lux E.sub.hor, which may equal to about 40 lux E.sub.eye may be chosen (high visual performance needed, no melatonin suppression). Light of 2400 K, R=0.23 may be provided. This may be produced using 100 LEDs, consuming 120 W.sub.el, giving 21000 lm. At hours of lower activity, lighting is dimmed to save energy and to reduce melatonin suppression. The light may be dimmed to 8 lux E.sub.eye, a flux of 4000 lm, the value of R=1.0 (about 3000 K) by dimming white LEDs to 18 W and adding 4 W.sub.el (2.8 W.sub.opt) of 480 nm blue LED.

[0165] In an example, e.g. for lighting for animal holdings/housing (e.g. Dairy cattle stable, pigs, chickens, aquaculture, zoo's . . . ), it may be desirable to extend the photoperiod beyond daylight with sufficiently high E.sub.eye, with e.g. >100 lux, to suppress melatonin. A light source of 36,000 lumen, CCT of 4500 K, may be applied, producing E.sub.eye=100 lux. During the extended photoperiod (the hours (typically 2 to 6) in the early night, immediately after sunset, the light source may be set to produce a lower light level e.g. 20 lux with R=0.2 to still have melatonin suppression. During the intended dark phase, a surveillance/observation light may be required. Typical light levels are around 5 lux (E.sub.hor). To prevent melatonin suppression, R may be >0.25, especially >0.4 (for equal visual performance of the farmer, with whiter light (higher R, higher CCT, higher CRI) a lower light level suffices. (e.g. the farmer may better perceive at 3 lux 4000 K CRI 70 than under 5 lux red light). In both cases, these regimes may apply to the first part of the lighted period; thereafter, the CCT may go down, e.g. to below 0.2.

[0166] In an example, e.g. for lighting of a patient room (institutionalized home environments), regular daytime light may be provided, with about 200 lux E.sub.eye (patient may be lying down); melatonin may be suppressed with B/Y about >0.25. For instance, 3500 lm from 15 LEDs, each consuming 2 W, 3000 K, B/Y=0.412 may be applied. Dimming down to observation nightlight, no suppression may be desired, thereby providing 20 lux, with 350 lm light. This may be done by dimming the white LEDs to 2.92 W.sub.el and adding 0.5 W.sub.el Blue led, resulting in a B/Y=1.46 (5200 K).

[0167] In an example, an observation nightlight is provided, where no suppression is desirable, with R>0.25, and E.sub.eye<30 lux. Occasionally, a higher light level can be needed for offering a more detailed viewbut without suppressing melatonin; then E.sub.eye may become >30 lux; therefore R may be reduced to <0.25. The latter may be produced using light sources of 22 W.sub.el LEDs of 2350 K, giving a flux of 5100 lm at R=0.64. Dimming down to 30% and adding 1 W.sub.el (0.7 W.sub.opt) of blue 450 nm LED light, may result in a flux of 1530 lm with R=0.73.

[0168] In an example, e.g. office workplace or indoor workplace, a luminaire of 4000 lm may be applied. High light level E.sub.eye may be >30 lux (e.g. 100 lux). For alertness, melatonin suppression is desirable. E.g. the CCT may be 4400 K, R=1.07; 10 W.sub.opt, 12 W.sub.el may be applied. When dimming to E.sub.eye=10 lux, but melatonin suppression still required R may e.g. be chosen to be 0.238. The lowest dim level may be realized using 2400 K LEDs 6 W.sub.el dimmed to 33%. Highest light output reached by increase to 100% and adding 12 W.sub.el of 6500 K white LEDs, to reach 4000 lm of 4400 K, R=1.07.

[0169] In an example, in a change from a E.sub.eye above 30 lux to one below 30 lux (or vice versa), while maintaining the same level of melatonin suppression (meaning R changes as well across the R=0.25 boundary), e.g. around 20 lux, R may especially be close to 0.25 to prevent an undesirable effect in melatonin suppression. So for any dimming curve going diagonally (see FIG. 2), the dimming curve may be a continuous function, passing through a region given by the boundaries 20E.sub.eye40 lux and/or 0.2R0.3. In other words, when dimming, while the same level of melatonin suppression may desirably be maintained, when E.sub.eye is between 20 and 40 lux, R is desirably close to 0.25, e.g. between 0.2 and 0.3.

[0170] The term plurality refers to two or more.

[0171] The terms substantially or essentially herein, and similar terms, will be understood by the person skilled in the art. The terms substantially or essentially may also include embodiments with entirely, completely, all, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term substantially or the term essentially may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%.

[0172] The term comprise also includes embodiments wherein the term comprises means consists of.

[0173] The term and/or especially relates to one or more of the items mentioned before and after and/or. For instance, a phrase item 1 and/or item 2 and similar phrases may relate to one or more of item 1 and item 2. The term comprising may in an embodiment refer to consisting of but may in another embodiment also refer to containing at least the defined species and optionally one or more other species.

[0174] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0175] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation.

[0176] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims.

[0177] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0178] Use of the verb to comprise and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words comprise, comprising, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of including, but not limited to.

[0179] The article a or an preceding an element does not exclude the presence of a plurality of such elements.

[0180] The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein.

[0181] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system.

[0182] The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and/or shown in the attached drawings.