Illumination system with automatic adaptation to daylight level

• US 8,575,846 B2
• Filed: 07/16/2009
• Issued: 11/05/2013
• Est. Priority Date: 07/23/2008
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Delnoij, Roger Peter Anna
• Primary Examiner(s): VU, JIMMY T
• Application Number:
  US13/054,657
• Publication Number:
  US 20110115386A1
• Time in Patent Office: 1,573 Days
• Field of Search: 315152-158, 315/209.R, 315/291, 315/294, 315/307, 315/308, 315360-363, 340/825.06, 340/825.72
• US Class Current: 315/152
• CPC Class Codes: G01J 1/16 using electric radiation detectors G01J1/20 takes precedence
• CPC Class Codes: G01J 1/32 adapted for automatic variation of the measured or reference value regulation of light intensity G05D25/00
• CPC Class Codes: H04Q 2209/43 using wireless personal area networks [WPAN], e.g. 802.15, 802.15.1, 802.15.4, Bluetooth or ZigBee
• CPC Class Codes: H04Q 2209/826 where the data is sent periodically
• CPC Class Codes: H04Q 2209/883 where the sensing device enters an active or inactive mode
• CPC Class Codes: H04Q 9/02 Automatically-operated arrangements
• CPC Class Codes: H05B 39/042 by measuring the incident light
• CPC Class Codes: H05B 47/10 Controlling the light source
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: H05B 47/17 Operational modes, e.g. switching from manual to automatic mode or prohibiting specific operations
• CPC Class Codes: H05B 47/19 via wireless transmission
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection

Abstract

An illumination system (10) comprises: —a light source (11); —a controller (12) controlling the power output of the light source; —a light sensor (16) wirelessly communicating with the controller. In a normal mode, the controller controls the light source such that the light level remains substantially constant. In a change mode, the controller controls the light source such that the light level is gradually changed with a predetermined change rate (R) such as to decrease a deviation from a target level (L_T). The controller switches from its normal mode to its change mode on the basis of input signals received from the light sensor. The light sensor measures a light level, and decides whether or not to communicate a signal to the controller. The light sensor refrains from transmitting a signal when receiving the signal will not cause the controller to change its control behavior.

Claims

1. An illumination system comprising:

at least one light source;

a controller for controlling the power output of the at least one light source;

a light sensor wirelessly communicating with the controller;

the controller being capable of operating

in a normal mode, in which the controller is configured to control the at least one light source such that a light level remains substantially constant, and

in a change mode, in which the controller is configured to control the at least one light source such that the light level is gradually changed with a predetermined change rate (R) so as to decrease a deviation from a target level (L_T), the controller being configured to switch from the normal mode to the change mode in response to one or more input signals received from the light sensor;

wherein the light sensor comprises a memory containing data defining at least one characteristic of the behaviour of the controller and is configured to intermittently measure the light level, and determine whether or not to communicate a signal to the controller based on the measured light level and the data contained in the memory, the light sensor being configured to refrain from transmitting the signal when receiving the signal does not cause the controller to change the behaviour of the controller,

wherein the sensor has information defining a predetermined upper margin (L_U) higher than the target level (L_T) and defining a predetermined lower margin (L_L) lower than the target level (L_T); and

wherein the sensor in a first mode is designed to refrain from transmission if the measured light level is between the upper margin (L_U) and the lower margin (L_L).

2. The system according to claim 1, wherein the sensor refrains from transmission within a predetermined time interval after a previous transmission.

3. The system according to claim 1, wherein the sensor, if the measured light level is higher than the upper margin (L_U), transmits a signal to the controller and obtains from the memory information defining a shifted target level (L_TS) higher than the target level (L_T), a shifted upper margin (L_US) higher than the shifted target level (L_TS), and a shifted lower margin (L_LS) lower than the shifted target level (L_TS);

wherein the controller, in response to receiving the measuring signal, is designed to gradually decrease the light output of the at least one light source;

wherein the sensor, after having transmitted the signal to the controller, operates in a second mode in which the sensor is adapted to gradually decrease the shifted upper margin (L_US) and the shifted lower margin (L_LS) and, at later measuring moments, to refrain from transmission if the measured light level is between the shifted upper margin (L_US) and the shifted lower margin (L_LS).

4. The system according to claim 3, wherein the sensor is adapted to switch from second mode to first mode when the shifted target level (L_TS) becomes equal to the original target level (L_T).

5. The system according to claim 4, wherein the controller has a memory containing a change rate for the light output of the at least one light source;

wherein the sensor has stored in the memory, data defining a change rate for the shifted target level (L_TS), the shifted upper margin (L_US) and the shifted lower margin (L_LS); and

wherein, if at the first measuring moment after the sensor has switched from second mode to first mode the sensor finds that the measured light level is higher than said upper margin (L_U) or lower than said lower margin (L_L);

the light sensor is designed to transmit the signal to the controller and switches to operating in the second mode;

the controller is designed to adapt the change rate in the memory of the controller;

the sensor is designed to adapt the change rate in the memory of the sensor in a corresponding manner.

6. The system according to claim 1, comprising

a first group of one or more lamps located proximately to an outside light source;

and

a second group of one or more lamps located farther from the outside light source than the first group of one or more lamps;

wherein the controller is designed to control a first dim factor of the first group of lamps and a second dim factor of the second group of lamps as a function of a sunlight level Lz, such that the second dim factor is always higher than or equal to the first dim factor;

wherein dim factor=zero indicates lamp OFF and dim factor=100% indicates lamp fully ON.

7. The system according to claim 6, wherein:

if the sunlight level Lz is between zero and a certain first value L1, the controller is designed to operate in a first mode in which y(61) =y(71) =100%;

if the sunlight level Lz is between the first value L1 and a certain third value L3, the controller is designed to operate in a second mode in which

y (61) =y(71) =100% ×

(L2−

Lz)/(L2−

L1),

L2 being a second value higher than the third value L3;

if the sunlight level Lz is between the third value L3 and the second value L2, the controller is designed to operate in a third mode in which

y(61) =100% ×

(L2−

Lz)/(L2−

L1),

y(71) =y(61)+B×

(Lz−

L3)/(L2−

L3),

B being a predetermined dim factor;

if the sunlight level Lz is between the second value L2 and a fourth value L4, the controller is designed to operate in a fourth mode in which

y(61) =δ

,

y(71) =B×

(L4−

Lz)/(L4−

L2),

if the sunlight level Lz is higher than the fourth value L4, the controller is designed to operate in a fifth mode in which

y(61) =y(71)=δ

.

8. The system according to claim 7, wherein δ

=0.

9. The system according to claim 7, wherein δ

initially is a small value higher than zero, and wherein the controller is designed to set δ

=0 after having operated in the fifth mode for a predetermined duration.

10. The system according to claim 1, wherein the signal transmitted by the sensor is a measuring signal indicating the value of the light level measured.

11. The system according to claim 1, wherein the signal transmitted by the sensor is a signal indicating that the value of the light level measured is higher than an upper margin (L_U) or lower than a lower margin (L_L).

12. An illumination system comprising:

at least one light source;

a controller for controlling the power output of the at least one light source;

a light sensor wirelessly communicating with the controller;

the controller being capable of operating

in a normal mode, in which the controller is configured to control a light source such that a light level remains substantially constant, and

in a change mode, in which the controller is configured to control the at least one light source such that the light level is gradually changed with a predetermined change rate (R) so as to decrease a deviation from a target level (L_T), the controller being configured to switch from the normal mode to the change mode in response to one or more input signals received from the light sensor;

wherein the light sensor comprises a memory containing data defining at least one characteristic of the behaviour of the controller and is configured to intermittently measure the light level, and determine whether or not to communicate a signal to the controller based on the measured light level and the data contained in the memory;

the light sensor being configured to refrain from transmitting the signal when receiving the signal does not cause the controller to change the behaviour of the controller, wherein the signal transmitted by the sensor is a signal indicating that the value of the light level measured is higher than an upper margin (L_U) or lower than a lower margin (L_L).