Naturalistic illumination system

• US 5,343,121 A
• Filed: 05/22/1990
• Issued: 08/30/1994
• Est. Priority Date: 10/09/1986
• Status: Expired due to Fees

• Current Assignee: Bill Perlman, Michael Terman, Stephen Fairhurst
• Original Assignee: Bill Perlman, Michael Terman, Stephen Fairhurst
• Inventors: Terman, Michael, Fairhurst, Stephen, Perlman, Bill
• Primary Examiner(s): LaRoche, Eugene R.
• Assistant Examiner(s): ZARABIAN, AMIR
• Application Number:
  US07/526,784
• Time in Patent Office: 1,561 Days
• Field of Search: 315/158, 315/157, 315/159, 315/160, 315/155, 315/151, 315/156, 315/307, 315/149, 315/194, 315/291, 315/360, 250/200-204
• US Class Current: 315/158
• CPC Class Codes: H05B 39/042 by measuring the incident light
• CPC Class Codes: H05B 41/3922 and measurement of the incident light
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]

Abstract

Apparatus for adjusting the circadian rhythm of a subject in a space by producing a variable light intensity level on a continuous basis in which there is a light source and the light output from the source made available to the subject in the space is controlled in response to a control signal which varies in a manner corresponding to the solar and lunar altitude of a predetermined geographical location and the passage of time over a selected time interval of the day at predetermined geographical location.

Claims

1. A naturalistic illumination system for a space for producing a changing total illumination level in the space corresponding to a predetermined portion of a day-night light cycle to adjust the circadian rhythm of a subject in the space comprising

light source means;

control means for controlling the amount of light produced by said light source means to be received by the subject in the space;

photosensitive means for measuring the current level of light produced by said light source means;

feedback means for providing data of light measurement from said photosensitive means to said control means; and

reference means for providing on a continuously changing basis for a predetermined time period changing data for said selected predetermined time period of an estimated momentary light level data which is continuously changing corresponding to repeatedly calculated momentary solar and lunar altitude and light levels for a particular latitude based on empirical constants and time and continuously advancing said changing data with respect to a given time reference of said selected predetermined time period, said reference means also providing the sum of said solar and lunar light levels, and providing the sum thereof to said control means as said continuously changing estimated momentary light level;

said control means repeatedly determining the difference between said estimated momentary light level and said current level of light and, if there is a difference therebetween, adjusting the amount of light produced by said light source means such that new current level of light will be produced which will substantially equal said estimated momentary level of light.

2. A naturalistic illumination system, as recited in claim 1, wherein said reference generating means additionally calculates momentary lunar altitude and light levels, sums said solar and lunar light levels and provides the sum thereof to said control means as said estimated momentary light level, said reference generating means providing estimates of momentary light levels across a 24-hour day, including twilight transition periods, the light emitted during said twilight transition periods closely mimicking corresponding natural twilight illumination.

3. A naturalistic illumination system, as recited in claim 1, wherein said reference generating means estimates the momentary proportions of a light emitting body being above versus being below the horizon and calculates light emitted from said body as a function of said proportion.

4. A naturalistic illumination system, as recited in claim 2, wherein said estimated lunar light levels are calculated as a function of an estimated phase of the moon.

5. A naturalistic illumination system, as recited in claim 1, wherein said estimated momentary light level is calculated as a function of atmospheric conditions.

6. A naturalistic illumination system, as recited in claim 1, further comprising light attentuation means associated with said light source, said light source emitting a substantially constant amount of light, said control means adjusting said light attentuation means for controlling the amount of light reaching said photosensitive means.

7. A naturalistic illumination system, as recited in claim 1, wherein said reference generating means maintains a clock for calculating estimated momentary light levels.

8. A naturalistic illumination system, as recited in claim 3, wherein said reference generating means maintains a clock for calculating estimated momentary light levels.

9. A naturalistic illumination system, as recited in claim 2, wherein said date is incremented by one at the end of each 24-hour period.

10. A naturalistic illumination system, as recited in claim 8, wherein said reference generating means provides estimates of momentary light levels for substantially all geographic latitudes.

11. A naturalistic illumination system, as recited in claim 1 further comprising a movable frame said light source and said control means being located on said frame, said photosensitive means being positionable within an area to be illuminated.

20. The apparatus according to claim 1, further comprising input means for supplying latitude, date and time data to said reference means.

12. A process for naturalistically illuminating a space with a continuously changing total natural illumination level corresponding to a predetermined portion of a day-night light cycle to adjust the circadian rhythm of a subject in the space, comprising the steps of repeatedly:

(a) measuring in the space the current level of light produced by an artificial light source means for receipt by the subject in the space whose light output can be controllably adjusted;

(b) providing the current light level measured in step (a) as feedback data to a control means;

(c) calculating an estimated natural light level changing over a selected predetermined portion of the day-night light cycle for a particular latitude on the surface of the earth by calculating momentary solar and lunar altitude and light levels based on empirical constants and date and time data with the time data and the light level corresponding thereto being continuously incremented with respect to a given time reference and summing said solar and lunar light levels; and

(d) determining the difference between said estimated momentary light level and said current level of light and, if there is a difference therebetween, adjusting the amount of light produced by said light source means such that a new current level of light will be produced which will substantially equal said estimated momentary level of light.

13. The process according to claim 12, wherein said process is repeated for at least two consecutive 24-hour periods, the estimated light values for which are determined as a function of the same date.

18. The process according to claim 12, wherein the process is repeated periodically during a 24-hour period with said time data incrementing according to 24-hour clock time.

19. The process according to claim 12, wherein said process is repeated for a period such that said time data varies by more than 24-hours and said date data is incremented by one at the end of a 24-hour period.

23. A process according to any of claims 12, 13, 18 or 19 wherein step (c) further comprises the steps of calculating momentary lunar altitude and light levels and summing said solar and lunar light levels to calculate the estimated momentary light level.

14. A naturalistic illumination system for a space for producing a changing total illumination level in the space corresponding to a selected predetermined portion of a day-night light cycle to adjust the circadian rhythm cycle of a subject in the space comprising:

light source means;

control means for continuously controlling the amount of light produced by from said light source means for receipt by the subject in the space to be substantially equal to a continuously varying estimated light level; and

reference generating means adapted to repeatedly and continuously (a) calculate over the predetermined portion of 24-hour day-night light cycle an estimated momentary light level for a selected given location on the surface of the earth wherein said reference generating means calculated momentary solar and lunar altitude and light levels based on latitude, date and time data and empirical constants with the time data and the light levels corresponding thereto being continuously updated relative to a changing reference time, (b) sum said solar and lunar light levels, and (c) provide the sum thereof to said control means as said estimated natural momentary light level for determining the amount of light to be produced by said light source means, the light level produced by said light source means varying over the selected predetermined portion of the 24-hour period updated to said estimated momentary light level and spanning approximating twilight transition light levels.

15. A naturalistic illumination system, as recited in claim 14, wherein said reference generating means estimates the momentary proportions of a light emitting body being above versus being below the horizon and calculates light emitted from said body as a function of said proportion.

16. A naturalistic illumination system, as recited in claim 15, wherein said estimated lunar light levels are calculated as a function of the estimated phase of the moon.

17. A naturalistic illumination system, as recited in claim 16, wherein said estimated momentary light level is calculated as a function of atmospheric conditions.

21. The apparatus according to claim 14, further comprising input means for supplying latitude, date and time data to said reference generating means.

22. A naturalistic illumination system for a subject, comprising:

a source for producing light, means to control the total amount of light to be received by the subject, means for measuring the actual level of light produced from said source, means for producing a calculated light level value corresponding to the altitude of a heavenly body and light levels for a selected earth related geographical location which value varies corresponding to the time of day at said location, said control means being responsive to the difference between said calculated light level value and said measured light level value to cause said source to produce light at said calculated light level value which is to be the total amount of light received by the subject.