FLUORESCENT LAMP PARTICULARLY SUITABLE FOR ILLUMINATING PLANT MATERIAL FOR CULTURE

Abstract: Artificial lighting is used for the culture of plant material in for instance closed climatic rooms. In order to achieve an optimum result a light intensity ratio between red with a wavelength of 635-685 nm and far red with a wavelength of 705-755 nm amounts to at least 1 and the ratio between red with a wavelength of 635-685 nm and blue with a wavelength of approximately 400-500 nm to about 1 for the light spectrum used.

Description: FLUORESCENT LAMP PARTICULARLY SUITABLE FOR ILLUMINATING PLANT MATERIAL FOR CULTURE Artificial lighting is used for the culture of plant material in climatic rooms which may or may not be closed. Different studies have been carried out into the optimum light intensity distribution in the spectrum for enhancing an optimum plant growth. An example of such a study is the article "Fundamental Studies on the Develop¬ ment of New Fluorescent Lamps for Plant Growth" by K. Murakami et al., published in Acta Horticulturae 319, 1992, Transplant Production Systems, pp. 329-332. Up to the present time however, the optimum distri¬ bution of the light intensity over the different components within the spectrum has not yet been determined. The invention has for its object to provide a fluo¬ rescent lamp which has a light intensity over the different constituent components which is optimal for plant growth. According to the invention this is achieved with a fluorescent lamp particularly for illuminating plant material for culture, wherein in the emitted light spectrum the light intensity ratio between red with a wavelength of 635-685 nm and far red with a wavelength of 705-755 nm amounts to at least 1 and the light intensity ratio between red with a wavelength of 635-685 nm and blue with a wavelength of 400-500 nm amounts to about 1. Practical tests have shown that with the light intensity ratio between the different components stated in the foregoing an optimum distribution for the growth of plant material is achieved. Attention is drawn to the fact that the frequency limits of the relevant components such as red, far red and blue can by their very nature not be accurately defined. These are flexible transitions. It has further been found that in order to obtain a practically applicable light spectrum for measuring plant material without daylight in for instance climatic rooms, the light spectrum must possess a determined energy level. According to the invention the proportion of the light intensity of red and blue between respectively 600-700 nm and 400-500 nm in the total light spectrum (400-700 nm) amounts together to 60-70% and the light intensity of blue between 400-500 nm amounts to about 20% of the total light spectrum (400-700 ran) . *****

Claims: CLAIMS 1. Fluorescent lamp, particularly for illuminating plant material for culture, wherein in the emitted light spectrum the light intensity ratio between red with a wavelength of 635-685 nm and far red with a wavelength of 705-755 nm amounts to at least 1 and the light intensity ratio between red with a wavelength of 635-685 nm and blue with a wavelength of 400-500 nm amounts to about 1. 2. Fluorescent lamp as claimed in claim 1, charac¬ terized in that the proportion of the light intensity of red and blue between respectively 600-700 nm and 400-500 nm in the total light spectrum (400-700 nm) amounts together to 60-70% and the light intensity of blue between 400-500 nm amounts to about 20% of the total light spectrum (400- 700 nm) . *****

Inventors: VAN LIEBURG MARIUS JAN, VERBEEK WILLEM, VAN LIEBURG, MARIUS, JAN, VERBEEK, WILLEM
Applicants: FLOWIL INT LIGHTING, FLOWIL INTERNATIONAL LIGHTING (HOLDING) B.V.
Application year: 1995
Main classification: H01J61
IPC codes: A01G7, H01J61