A hearing device utilizes the effect of forming combination tones from two different tones within the ear based on non-linear transmission characteristics of the ear. The lid member is usable with a system for dispensing the paint component from its original container into a paint receptacle according to a paint formula to form a liquid paint mixture. The ferroelectric liquid crystal, when no electric field is applied to it, goes into a planer state in which a helical axis becomes perpendicular to or almost perpendicular to the substrates, selectively reflecting light of specific wavelengths in a visible region. However, such a slow response is unsuitable for applications requiring overvoltage protection. The processing continues by comparing the first measured signal strength with the second measured signal strength to determine whether the filter has attenuated the second signal by a desired attenuation value with respect to the first signal. The gist of the present invention is to structurally separate the optical signal propagating waveguide from another optical waveguide which serves as a lasing optical cavity for optical amplification in such a manner that the two optical waveguides are formed in the same plane but not parallel to each other.