Film thickness measuring method and measuring apparatus for organic thin film for use in organic electroluminesce device

#This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-086992, filed Mar. 26, 2002, the entire contents of which are incorporated herein by reference.

#1. Field of the Invention

#The present invention relates to a film thickness measuring method and a film thickness measuring apparatus using fluorescence which is applicable to measurement of the film thickness of an organic electroluminescence device (hereinafter referred to as an organic EL device).

#FIG. 1 is a diagram showing a cross section configuration of an organic EL device;

#FIG. 2 is a conceptual diagram of a fluorescence film thickness measuring apparatus in a first embodiment of this invention;

#FIG. 3 is a conceptual diagram of the fluorescence film thickness measuring apparatus in a second embodiment of this invention;

#The present invention will hereinafter be described in detail in accordance with specific embodiments shown in the accompanying drawings. In the description of the embodiments below and the illustration in the drawings, like reference numerals indicate like elements.

#FIG. 2 shows a first embodiment of this invention, and there are provided a pin hole 15 disposed between an ultraviolet light source 11 disposed under an organic EL device 16 and the organic EL device 16, and a photodetector 12 disposed above the organic EL device 16. The pin hole 15 may be disposed between the organic EL device 16 and the photodetector 12. An ultraviolet light protection filter 18 may be provided between the organic EL device 16 and the photodetector 12 as needed.

#As the ultraviolet light source 11, it is possible to use a light source capable of releasing an ultraviolet light, such as a fluorescent test light, xenon lamp, deuterium lamp or nitrogen laser, having a wavelength to excite organic materials constituting the organic EL device 16, preferably a wavelength of 200 nm to 380 nm. For the photodetector 12, a photodiode, a phototransistor, a multichannel spectroscope and a CCD sensor are available, for example. By disposing the organic EL device on an XY movable stage 22, it is possible to readily measure a film thickness distribution within a surface. For example, an interference filter having a plurality of transparent dielectric thin film layers with different refractive indices optical thickness of which is on a level of the wavelength can be used for the ultraviolet light protection filter 18. In this case, it is possible to use a long wavelength pass light filter for shutting off the irradiated ultraviolet light, or a band pass light filter for mainly allowing only excitation light inherent in each organic material to pass.