Recently, microplasmas of sub-millimeter to micrometer scales are of much interest for various applications such as displays, light sources, micro total analytic systems, micromachining tools, and so on. Microplasmas can be operated not only as a sole device but also in one or two dimensional arrays. In addition, those are operated at a higher pressure range, including atmospheric pressure, according to the shrinkage of the sizes. These features make their potential larger for wider applications. If we use gas discharges for the generation of microplasmas, the electrode configuration is categorized as counter, coplanar, and coaxial electrode types. The dielectric barrier discharge (DBD) scheme is also advantageous in their parallel operation in arrays, where electrodes are covered by dielectric materials for preventing the current concentration automatically thanks to the accumulated surface charge. As the first example, several types of microdischarges are introduced which are used in plasma display panels. Experimental results on spatiotemporal behaviors of microplasmas in unit discharge cell are explained, where the excited species have been diagnosed by using a laser absorption spectroscopy method and the electron density by a mm-wave transmission technique. Those results are discussed for the improvement of luminous efficiency. As the second example, a coaxial mesh-type DBD with a microplasma integrated structure is explained as a large area plasma source for the purpose of various surface treatment technologies. The superior performances are explained in a comparison with those of a conventional parallel plate DBD system for the wider parameter ranges of stable operations. As the third example, our new idea of microplasma devices for the control (switching, filtering, etc.) of microwaves will be explained by using the dielectric properties of plasmas. This idea can be expanded towards microplasma photonic crystals.