Comparing the lens displacement profile data by using the sequential approach for selecting alternative suppliers

The lens module is a critical part of the camera module. The quality of the lens module significantly influences the auto-focus and image stability functions of the camera module. A new approach that uses sequential tests is proposed to select the alternative suppliers that provide the qualified parts as the current supplier under the linear profile data. Having several qualified alternative suppliers can reduce the dependency on one supplier, improve bargaining power, and reduce capacity risk. The lens displacement that has a linear relationship with current is the quality characteristic for evaluating the lens module suppliers. To select the qualified alternative suppliers, the proposed sequential approach tests the profile difference between the current supplier and the investigated suppliers. The simulation results show that the power of the sequential approach is higher than the simultaneous confidence bands method in differentiating profiles. Last, the proposed approach is effectively applied to select the qualified alternative lens module suppliers for the camera module manufacturer. Procuring the lens module from the selected suppliers can maintain production quality and flexibility for the camera module manufacturer in practice.