LED Array Brightness Control via Single Sensor Current Compensation
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Solution Overview
Problem
Existing display devices with light-emitting diode arrays require numerous current sensors to detect operating current values, leading to high costs and reduced accuracy in brightness adjustment, as using a common sensor for multiple diodes results in only whole light-emitting area control rather than individual diode control.
Innovation Solution
A method that calculates operating current values for each light-emitting diode using a common current sensor, obtaining compensation signals to adjust pulse signals, allowing for precise brightness control by establishing light-emitting time intervals and performing compensation operations based on sensed overall current values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensor is provided for each light-emitting diode to detect operating current values, then measurement precision of individual diode current is improved, but device complexity and cost increase due to the large number of sensors required
Solution Approach 1:
The patent merges multiple current sensing functions into a single current sensor that detects the total current of the entire light-emitting diode array. By combining individual diode current information with emission timing data, the system reconstructs individual diode current values through calculation rather than direct measurement, thereby reducing sensor quantity while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary calculation process that acts as a mediator between the single current sensor and individual diode control. The controller uses the total current measurement combined with emission timing information to calculate individual diode current values, serving as an intermediary mechanism that enables precise individual control without requiring individual sensors for each diode.
2Device complexity
If a common current sensor is used for multiple light-emitting diodes to reduce the number of sensors, then device complexity is reduced, but measurement precision deteriorates because only the sum of operating current values can be detected
Solution Approach 1:
The patent segments the current detection process into two parts: (1) a single sensor measures the total current of the entire array, and (2) the controller segments this total current into individual diode contributions by utilizing emission timing information. This segmentation approach allows the system to obtain individual diode current values from a collective measurement, maintaining precision while reducing hardware complexity.
Solution Approach 2:
The patent applies preliminary action by having light-emitting diodes emit light in a predetermined sequential order with known timing relationships. This pre-established emission sequence allows the controller to correlate total current measurements with specific diode activation times, enabling backward calculation of individual diode current values without requiring individual sensors.
3Device complexity
If light-emitting diodes are controlled as a whole light-emitting area using a common current sensor, then device complexity is reduced, but manufacturing precision of brightness adjustment deteriorates
Solution Approach 1:
The patent introduces dynamic control by sequentially activating individual light-emitting diodes in a predetermined order rather than controlling them simultaneously as a static whole. The controller dynamically processes current measurements based on which diodes are currently emitting, enabling precise brightness adjustment for each diode individually while using a single current sensor, thus achieving both simplicity and precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the number of current sensors needed, lowers costs, and enables accurate brightness adjustment of individual light-emitting diodes within a display device by using compensation signals to adjust pulse signals.
Implementation Method 1
n number of light-emitting diode columns (e.g., L1 ̃Ln), each of the light-emitting diode columns includes m number of light-emitting diodes (e.g., LED1 ̃LEDm)... sequentially providing operating pulse signals to the m number of light-emitting diodes... sequentially enabling (i.e., generally lighting on) the m number of light-emitting diodes
Implementation Method 2
sensing a plurality of overall current values flowing the m number of light-emitting diodes at different timings
Data Source
AI summary
A light-emitting adjustment method and a display device are provided. The display device includes a voltage source, a light-emitting diode array, a pulse width modulator, a current sensor and a light-emitting adjuster. The voltage source provides an operating voltage. The pulse width modulator provides operating pulse signals to multiple light-emitting diodes arranged in column in order. The current sensor senses a plurality of overall current values of the light-emitting diodes at different timings during the light-emitting diodes are sequentially enabled. The light-emitting adjuster computes an operating current value of each of the light-emitting diodes according to the overall current values and performs a compensation operation based on the operating current value to obtain and output a compensation signal.