To effectively prevent light emission in a certain direction from affecting viewers, such as the reflections produced by automotive display screens on the front windshield, this paper proposes a polymer-stabilized liquid crystal device that prevents light emission in a specific direction. This unidirectional light-blocking liquid crystal device is based on a twisted nematic (TN) structure. By applying an electric field, the liquid crystal director’s profile in the liquid crystal layer is appropriately controlled. In this state, ultraviolet light is used to cure the polymer monomers dispersed in the liquid crystal, forming a stable polymer network that fixes the orientation of the liquid crystal molecules. When the electric field is removed and the polarizer is adhered to, a unidirectional light-blocking effect is achieved, fulfilling the desired requirement. Experimental results show that the proposed unidirectional light-blocking device can prevent light from passing through at specific angles, with a maximum transmittance of 89% at the normal viewing angle. The double-layer structure significantly reduces light leakage at large angles while maintaining a maximum transmittance of 70% at the normal viewing angle, providing a better unidirectional light-blocking effect. This work demonstrates that polymer-stabilized twisted nematic liquid crystal devices can offer unidirectional light-blocking characteristics while maintaining high transmittance in the forward direction, making them highly suitable for special applications in personal electronic products, vehicle displays, and safety information terminals, thus possessing significant practical value.