| 摘要 |
PROBLEM TO BE SOLVED: To easily provide a desired white color or intermediate color by arranging a wavelength converting layer on a reflecting film, arranged adjacently to a light source and provided on the reverse side of a surface light guide plate optically connected thereto in such a manner as to be replaceable. SOLUTION: A wavelength converting material as a fluorescent material, which emits fluorescence by excitation of ultraviolet ray of a light source such as YGA is laid into a solution state by use of a solvent together with a resin component, such as acryl and applied onto a reflecting film 3 arranged so as to cover the reverse side of a light guide plate 2, whereby a wavelength converting layer 4 is formed. When a blue LED is used as the light source 1, the ultraviolet ray is wavelength-converted to form fluorescence. When a white light is desired, for example, a mixture of red and green fluorescent pigments is used as the fluorescent material to emit yellow light, whereby the yellow reflected light is mixed with the blue light of the LED within the light guide plate 2 to provide the white light. The fluorescent material layer 4 and the wavelength of the light source are properly selected, whereby not only white but also subtle intermediate colors can be emitted. |
