A user's phone does not respond to touch. A technician inspects the phone but does not see any evidence of physical damage. The technician restarts…

The digitizer is the component of a touch screen assembly responsible for sensing and converting physical touch into a digital signal. When a phone's screen displays an image correctly but does not respond to touch, it indicates a failure in this specific layer. Since a restart did not resolve the issue, a software glitch is less likely, and the next logical step is to suspect a hardware failure of the digitizer itself. The digitizer is often fused with the display screen but is a distinct functional component.

A. A faulty battery would cause power-related issues, such as the device not turning on or shutting down, not a non-responsive touch screen.

B. The screen (e.g., LCD/OLED panel) is responsible for displaying the image. The user did not report a display issue, only a touch issue.

C. A stylus is an external input device. Its failure would not prevent the screen from responding to a finger touch.

1. Layton, J., & Valdes, R. (2006). How the iPhone Works. HowStuffWorks. Updated by C. Lampton. Section: "iPhone Touch Screen". "The screen is a capacitive touch screen... The layer that does the sensing is the digitizer." This principle applies to modern smartphones.

2. Samsung Electronics. (2019). Galaxy S10 Service Manual (SM-G973F). Section 4: "Disassembly and Reassembly," p. 4-15. The manual identifies the "Front OCTA (On-Cell Touch AMOLED)" as a single assembly containing the display and touch sensor (digitizer), which must be replaced for touch failures.

3. Walker, G. R. (2012). A review of technologies for sensing contact location on the surface of a display. Journal of the Society for Information Display, 20(8), 413-440. (DOI: 10.1002/jsid.100). This academic review details the function of various digitizer technologies (e.g., capacitive, resistive) used in touch screens.