This paper presents an approach for design a continuous-time interval observer for linear parameter varying (LPV) systems in the presence of disturbances that are considered unknown but bounded. The proposed observer is used for the design of a sensor fault detection scheme using the input to state stability (ISS) approach through a Lyapunov quadratic function. The conditions of stability and positivity are presented by a set of linear matrix inequalities (LMIs). The performance of the proposed method is shown in simulation using a case study based on a single-link flexible joint robotic system.