# US 12,178,171 B2 · System and method for controlling a light source illuminating plants in a greenhouse

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- Number: US 12,178,171 B2
- Document ID: US12178171B2
- Status: Granted
- Kind: B2
- Application number: 18/236,436
- Filed: 2023-08-22
- Published: 2024-02-29
- Granted: 2024-12-31
- Earliest claimed: 2022-08-23
- Assignees: Ledgnd B.V.
- Applicants: Ledgnd B.V.
- Inventors: Maarten Van Bemmel; Ramón Van de Vrie
- Web page: https://patentgrep.com/patent/US12178171B2

## CPC

- A01G 9/249: {Lighting means (with special arrangements for promoting growth A01G7/045)}
- A01G 7/045: {with electric lighting}
- H05B 45/22: using optical feedback
- A01G: HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING (picking of fruits, vegetables, hops or the like A01D46/00; propagating unicellular algae C12N1/12)
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL

## Abstract

A system for controlling a light source illuminating plants in a greenhouse, the system includes: a sensor for detecting a first spectrum of ambient light, the sensor being configured to measure incident intensities in at least two wavelength ranges, and a control unit for adjusting a second spectrum of the light source in dependency of the measured intensities in the at least two wavelength ranges; and a method for operating a system for controlling a light source illuminating plants in a greenhouse, the method includes a measuring step where the sensor detects incident intensities in at least two wavelength ranges, and an adjustment step the second spectrum of the light source is adjusted in dependency of the measured intensities in the at least two wavelength ranges.

## Claims

### Claim 1

A system for controlling a light source illuminating plants in a greenhouse, the system comprises:
a sensor for detecting a first spectrum of ambient light, the sensor comprises eighteen channels or eighteen sensors for detecting eighteen first spectra of the ambient light, wherein one or the eighteen sensors are configured to measure incident intensities in eighteen wavelength ranges; and
a control unit for adjusting a second spectrum of the light source in dependency of the measured incident intensities in the eighteen wavelength ranges, wherein spectral distributions of the eighteen intensities are arranged in an overlapping manner, wherein the control unit is configured to normalize the measured incident intensities.

### Claim 2 (depends on 1)

The system according to claim 1, wherein the sensor is configured to operate over a bandwidth ranging from 385 nm to 1000 nm.

### Claim 3 (depends on 1)

The system according to claim 1, wherein the wavelength ranges are spaced apart by 10 nm to 50 nm steps, or 15 nm to 40 nm steps, or by 20 to 30 nm steps.

### Claim 4 (depends on 1)

The system according to claim 1, wherein each of the eighteen wavelength ranges comprise an interval size of 10 nm, or less than 7 nm, or less than 5 nm.

### Claim 5 (depends on 1)

The system according to claim 1, wherein the system comprises two sensors, wherein a first sensor of the two sensors being arranged at a first altitude below the light source, and a second sensor of the two sensors being arranged at a second altitude above the light source.

### Claim 6 (depends on 1)

The system according to claim 1, wherein the control unit is configured to compare the measured incident intensities in the wavelength ranges with prestored values.

### Claim 7 (depends on 6)

The system according to claim 6, wherein for each plant a growth-promoting second spectrum is prestored.

### Claim 8 (depends on 1)

The system according to claim 1, wherein the control unit is configured to normalize the measured incident intensities to values between 0 and 1 or 0% and 100%.

### Claim 9

A method for operating a system for controlling a light source illuminating plants in a greenhouse, wherein the system comprises,
a sensor for detecting a first spectrum of ambient light, the sensor comprises eighteen channels or eighteen sensors for detecting eighteen first spectra of the ambient light, wherein one or the eighteen sensors being configured to measure incident intensities in eighteen wavelength ranges, and
a control unit for adjusting a second spectrum of the light source in dependency of the measured incident intensities in the eighteen wavelength ranges,
wherein in a measuring step, the sensor detects incident intensities in at least two wavelength ranges, and in an adjustment step, the second spectrum of the light source is adjusted in dependency of the measured incident intensities in the eighteen wavelength ranges, and
wherein spectral distributions of the eighteen intensities are arranged in an overlapping manner, wherein the control unit is configured to normalize the measured incident intensities.

### Claim 10 (depends on 9)

The method according to claim 9, wherein the sensor operates over a bandwidth ranging from 385 nm to 1000 nm.

### Claim 11 (depends on 9)

The method according to claim 9, wherein the sensor measures intensities in wavelength ranges that are spaced apart by 10 nm to 50 nm steps, or 15 nm to 40 nm steps, or by 20 to 30 nm steps.

### Claim 12 (depends on 9)

The method according to claim 9, wherein in a comparison step, that follows the measuring step and precedes the adjustment step, the control unit compares the measured incident intensities in the wavelength ranges with prestored values.

### Claim 13 (depends on 12)

The method according to claim 12, wherein the control unit compares the measured incident intensities with plant-specific prestored values.

### Claim 14 (depends on 9)

The method according to claim 9, wherein in a comparison step, that follows the measuring step and precedes the adjustment step, the control unit normalizes the measured incident intensities.

### Claim 15 (depends on 9)

The method according to claim 9, wherein the control unit is configured to normalize the measured incident intensities to values between 0 and 1 or 0% and 100%.