Illuminator for plant growth

• US 20030009933A1
• Filed: 08/19/2002
• Published: 01/16/2003
• Est. Priority Date: 02/22/2000
• Status: Active Grant

• Current Assignee: CCS Corporation
• Original Assignee: CCS Corporation
• Inventors: Takahata, Minoru, Hayashi, Takahiro, Yoneda, Kenji
• Granted Patent: US 8,074,397 B2
• Time in Patent Office: Days
• US Class Current: 47/1.01R
• CPC Class Codes: A01G 7/045 with electric lighting
• CPC Class Codes: Y02P 60/14 Measures for saving energy, e.g. in green houses
• CPC Class Codes: Y10S 47/06 Plant growth regulation by control of light thereon

Abstract

To provide an illuminator for plant growth that can illuminate a plant intermittently (pulse illumination) or continuously to cause an effect similar to sunbeam spot phenomenon, thereby accelerating photosynthetic reaction.

Specifically, the illuminator for plant growth includes a light source composed of a semiconductor optical device, a control unit for outputting a turn-on timing signal for the light source, a rhythm signal detecting unit for A/D converting an input rhythm signal, a timing signal modulating unit for modulating the turn-on timing signal with the output signal from the rhythm signal detecting unit, and a pulse drive unit for pulse-modulating a power signal with the modulated turn-on timing signal outputted from the timing signal modulating unit and supplying the pulse-modulated power signal to the light source.

Claims

1. An illuminator for plant growth, wherein the illuminator comprises a light source composed of a semiconductor optical device, modulates light generated by the light source with a rhythm signal produced artificially or a rhythm signal extracted from sound present in nature, and illuminates a plant to be illuminated with the modulated light.

2. The illuminator for plant growth according to claim 1, wherein said rhythm signal produced artificially is a rhythm signal extracted from a musical composition.

3. The illuminator for plant growth according to claim 1 or 2, wherein the illuminator comprises a light source composed of a semiconductor optical device, a control unit for outputting a turn-on timing signal for the light source, a rhythm signal detecting unit for taking in an input rhythm signal, a timing signal modulating unit for modulating said turn-on timing signal with the output signal from the rhythm signal detecting unit, and a pulse drive unit for pulse-modulating a power signal with the modulated turn-on timing signal outputted from the timing signal modulating unit and supplying the pulse-modulated power signal to said light source, whereby the plant to be illuminated is pulse-illuminated while changing a light quantity of the light source in synchronization with said input rhythm signal.

4. The illuminator for plant growth according to claim 3, wherein said timing signal modulating unit modulates the turn-on timing signal with the output signal from said rhythm signal detecting unit so as to change a pulse width or pulse cycle time of the power signal.

5. The illuminator for plant growth according to claim 3, wherein the illuminator further comprises a pulse height modulating unit for modulating an amplitude of the power signal supplied from said pulse drive unit to the light source with the output signal from said rhythm signal detecting unit, and a pulse height of pulsed light generated by the light source is modulated.

6. The illuminator for plant growth according to any one of claims 1 to 5, wherein said light source comprises a plurality of semiconductor optical devices having different emission wavelength regions.

7. The illuminator for plant growth according to claim 6, wherein said control unit generates the turn-on timing signals for each of the semiconductor optical devices having different emission wavelength regions, said timing signal modulating unit modulates said turn-on timing signals with the output signal from said rhythm signal detecting unit for each of the semiconductor optical devices, and said pulse drive unit pulse-drives each semiconductor optical device in the light source according to the respective output signals from the timing signal modulating unit.

8. The illuminator for plant growth according to claim 6 or 7, wherein a semiconductor optical device having a luminescent color of red and a semiconductor optical device having a luminescent color of blue are used for said semiconductor optical devices having different emission wavelength regions.

9. The illuminator for plant growth according to claim 8, wherein, in the luminescent colors of said semiconductor optical devices, a spectral ratio between red (R) and blue (B) (R/B ratio) is set within a range from 1 to 10.

10. The illuminator for plant growth according to any one of claims 1 to 5, wherein a white light emitting diode is used for said semiconductor optical device.

11. The illuminator for plant growth according to any one of claims 1 to 10, wherein said timing signal modulating unit multiplies the output signal from said rhythm signal detecting unit by the turn-on timing signal generated by said control unit to generate a signal synchronized with an amplitude of the rhythm signal, and sums the signal and said turn-on timing signal to modulate said turn-on timing signal.

12. The illuminator for plant growth according to any one of claims 1 to 11, wherein a sensor for monitoring a plant condition including a potential of the plant is provided, and when the plant is to be pulse-illuminated, based on measurement data of the sensor, a dimming pattern for generating said turn-on timing signal is set for optimal activation of the plant, or switching among a plurality of dimming patterns previously stored is performed for optimal activation of the plant.

13. The illuminator for plant growth according to any one of claims 1 to 11, wherein various sensors for measuring environmental factors of the plant including atmospheric temperature, carbon dioxide concentration, and water temperature are provided, and when the plant is to be pulse-illuminated, based on measurement data of the sensors, a dimming pattern for generating said turn-on timing signal is set for optimal activation of the plant, or switching among a plurality of dimming patterns previously stored is performed for optimal activation of the plant.