Thick films of 200㎛ with the composition of $(Pb_{0.9}La_{0.1})TiO_3$ were fabricated by tape-cating method using a commercial binder, B73210 and the pyroelectric and the dielectric properties at room temperatrure were investigated. The relative densities of the thick films sintered at 1250℃ for over 30 minutes were over 90% of theoretical density. The pyroelectric figure-of-merits of thick films were as good as that of bulk PLT ceramics. Grain size effect was examined. In the case that the grain size was over 2.7㎛, the larger the grain size, the larger the pyroelectric coefficient and the relative dielectric constant. This was explained by the difference in the amount of 90° domain switching by poling and the space charge in the grain boundary and the domain. When the grain size was 1.3㎛, however, the pyroelectric and dielectric properties was anomalously high. This was considered to result from the inhomogeneous internal stress, which was confirmed from the results of FWHM, showing the largest value in the film of 1.3㎛ grain size. Effect of $MnO_2$ addition was also examined. As the amount of $MnO_2$ increased, the grain size decreased, the density increased, the pyroelectric coefficient increased, and the relative dielectric constant decreased. So the pyroelectric figure-of-merit of $MnO_2$-doped $(Pb_{0.9}La_{0.1})TiO_3$ thick films was much better than that of undoped one.
