PWM Display Dimming: what it is, how it works and what it does

Definition

PWM display dimming uses pulse-width modulation to regulate a display's perceived brightness. Rather than describing only continuous light emission at a lower intensity, this approach controls a signal through on-and-off cycles.

Operating principle

With PWM, the signal is arranged into repeating pulses. Brightness is controlled by varying the proportion of time that the signal remains active within each cycle; this proportion is commonly called the duty cycle.

The PWM frequency indicates how many modulation cycles occur per second and is expressed in hertz (Hz). It is a dimming parameter, not a general label for screen resolution or size.

Relationship to refresh rate

Refresh rate and PWM frequency describe different parameters. The former concerns the rate at which the image is updated; the latter concerns the rate of brightness modulation. They can therefore appear together in display specifications without referring to the same function.

Available data

The supplied evidence states 120 Hz, 4320 Hz PWM (claim_id: 1528). In that record, 120 Hz is presented as the refresh rate and 4320 Hz PWM as the modulation frequency used for dimming.

The evidence does not identify a product, a brightness mode, a luminance level, or the measurement conditions associated with these figures.

How to interpret this feature in a product

• A reference to 4320 Hz PWM reports the stated frequency for brightness modulation.
• A reference to 120 Hz should be interpreted separately as the refresh rate.
• Assessing a particular implementation requires additional information about the product and the conditions in which PWM is applied.

Scope and limitations of the information

Based on the supplied evidence, the two stated figures can be reported, but they cannot be assigned to a specific model or used to infer behavior at every brightness level. The panel architecture, display modes, and other brightness-control methods are not specified.