Abstract: A drive force control part 5 controls a drive force such that a force caused by a change in the drive force to rearwardly tilt a drive source 1 and push a mount member is made smaller than an external force threshold value. In a first region in which the drive force is equal to or above a predetermined lower limit value, the drive force control part 5 limits a change rate per unit time of the drive force to or below a predetermined maximum rate, and in a second region in which the drive force is smaller than the lower limit value, does not limit the change rate per unit time of the drive force to or below the maximum rate.

Abstract: A drive force control part 5 controls a drive force such that a force caused by a change in the drive force to rearwardly tilt a drive source 1 and push a mount member is made smaller than an external force threshold value. In a first region in which the drive force is equal to or above a predetermined lower limit value, the drive force control part 5 limits a change rate per unit time of the drive force to or below a predetermined maximum rate, and in a second region in which the drive force is smaller than the lower limit value, does not limit the change rate per unit time of the drive force to or below the maximum rate.

Abstract: The purpose of the present invention is to provide a retardation film which includes cellulose acetate having a low degree of acyl substitution and, despite this, swells very little when immersed in a saponifying solution and which has satisfactory adhesion to polarizing elements. This retardation film comprises: a cellulose ester which has a total degree of substitution with acyl groups of 2.0-2.55 and in which when log [Mw(a)] obtained through analyses by gel permeation chromatography (GPC), low angle laser light scattering (LALLS), and viscosity measurement, is plotted as abscissa and log [Iv(a)], obtained through the analyses is plotted as ordinate, the plot has a slope of 0.65-0.85; and a glass-transition-temperature lowering agent having an SP value of 9.0-11.0. The retardation film contains a solvent remaining therein in an amount of 700-3,000 mass ppm and has a change in weight through storage at 80° C. and 90% RH of ?0.5 to 0.5%.