A phase-only spatial light modulator is a highly efficient component for the filter plane of a real-time correlator. Implementation using flexure-beam micromechanical devices offers many advantages, such as high reflectivity and a high frame rate. However, extra effort is required to ensure high optical efficiency and low parasitic noise. This paper reports on the Texas Instruments implementation of a limited-addressability flexure-beam device that has a fill factor up to 74.3% and provides a dc shield for the analog signal on the mirror. It requires 30 V to modulate the 2π phase modulation of a 633-nm wavelength using an optical-bench setup. The rise and fall times are approximately 3.5 and 2.5 μs, respectively, at π modulation of 546 nm using an interlerometric microscope.