Variable Rate Backlight Brightness Control
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Solution Overview
Problem
Existing display technologies abruptly adjust backlight brightness in response to ambient light changes, causing distracting or disturbing user experiences due to sudden changes in illumination levels.
Innovation Solution
Implementing dynamic backlight brightness control that adjusts rates based on the direction and magnitude of ambient light changes, using multiple filters with varying sampling periods to customize brightness adjustments for different lighting scenarios, and incorporating hysteresis delays to prevent abrupt changes in low-light environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the backlight brightness is immediately adjusted to the target level in response to ambient light changes, then the system responds quickly to lighting changes, but the abrupt brightness changes cause distracting or disturbing user experiences
Solution Approach 1:
The patent applies dynamics by making the backlight adjustment rate variable rather than fixed. The system dynamically adjusts the brightness change rate based on the direction of ambient light change (increasing or decreasing) and the current brightness level, creating a non-linear adjustment curve that is faster in brightening scenarios and slower in darkening scenarios to match human visual adaptation characteristics
Solution Approach 2:
The patent implements beforehand cushioning by introducing a hysteresis delay mechanism that prevents immediate brightness adjustments. A delay counter is used to postpone brightness changes until the ambient light level has consistently exceeded or remained below thresholds for a predetermined number of sampling periods, cushioning against premature or erratic brightness changes that would distract users
2Object-affected harmful factors
If the backlight brightness is adjusted slowly to avoid abrupt changes, then user experience is improved, but the system response to lighting changes becomes too slow
Solution Approach 1:
The system dynamically adjusts the brightness change rate based on the direction of ambient light change. When ambient light is increasing, the brightness adjusts at a faster rate; when ambient light is decreasing, the brightness adjusts at a slower rate. This dynamic adjustment strategy matches human visual adaptation characteristics and resolves the contradiction between speed and smoothness
3Adaptability or versatility
If the system uses a fixed brightness adjustment rate, then the control logic is simple, but the system cannot optimize for different lighting scenarios
Solution Approach 1:
The patent changes the parameter of brightness adjustment rate from a fixed value to a variable that depends on ambient light conditions. The system defines different brightness change rates for different ambient light ranges and directions of change, allowing optimization for specific lighting scenarios while managing complexity through predefined thresholds and ranges
Data Source
AI summary
An electronic device includes a display including an emission unit, a light sensor configured to generate a signal indicative of ambient light level, a memory in which filtering instructions and emission control instructions are stored, and a processor configured to implement the filtering instructions to generate at least one filtered representation of the ambient light level in accordance with the signal. The processor is further configured to implement the emission control instructions to determine whether the ambient light level is increasing or decreasing, and to generate a control signal that, based on the at least one filtered representation, increases a brightness level of the emission unit at a first rate if the ambient light level is increasing and that decreases the brightness level at a second rate if the ambient light level is decreasing. The first rate is greater than the second rate.