Source Driver Ladder Resistor Circuits for Display Luminance
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Solution Overview
Problem
In large-sized display panels, luminance unevenness occurs due to variations in wiring resistance values of connection lines between semiconductor IC chips and the reference voltage source, causing differences in the level of drive voltage received by each chip.
Innovation Solution
A source driver with a gradation voltage generation circuit that uses multiple reference voltages and ladder resistor circuits to generate and divide voltages, ensuring consistent gradation voltages across the panel, even with varying connection line lengths, by extending the range of reference voltages generated by both first and second ladder resistor circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single reference voltage source is used for multiple semiconductor IC chips, then the device complexity is reduced, but luminance unevenness occurs due to varying connection line lengths and wiring resistance values
Solution Approach 1:
The reference voltage source is segmented into multiple independent reference voltage sources, with each semiconductor IC chip having its own dedicated reference voltage source. This segmentation eliminates the problem of luminance unevenness caused by varying connection line lengths, as each chip receives a stable reference voltage without interference from other chips' wiring resistance variations.
2Area of stationary object
If connection lines are extended to cover large panel areas, then the display size is increased, but wiring resistance variations cause drive voltage level differences across chips
Solution Approach 1:
By dividing the single reference voltage source into multiple separate reference voltage sources distributed across different semiconductor IC chips, the system can cover large panel areas while maintaining drive voltage consistency. Each chip's local reference voltage source eliminates the accumulation of wiring resistance effects over long connection lines.
3Manufacturing precision
If multiple reference voltage sources are provided for each semiconductor IC chip, then luminance uniformity is improved, but the device complexity increases
Solution Approach 1:
The reference voltage source is segmented and integrated into each semiconductor IC chip individually. This approach achieves luminance uniformity by eliminating wiring resistance variations while the integration within each chip minimizes the overall device complexity compared to having separate external reference voltage sources for each chip.
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 solution effectively curbs luminance unevenness by ensuring that gradation voltages corresponding to the same luminance level are generated consistently across the display panel, regardless of connection line length differences, thereby improving image display quality.
Implementation Method 1
a first ladder resistor circuit including a plurality of first resistors connected to each other in series between the first connection point and the second connection point, generating a plurality of first divided voltages by dividing a voltage difference between the first reference voltage and the second reference voltage using the plurality of first resistors
Data Source
AI summary
A first ladder resistor circuit including multiple first resistors connected to each other in series between a first connection point to which a first reference voltage is supplied and a second connection point to which a second reference voltage is supplied, and outputting multiple first divided voltages as the first reference voltages of multiple reference voltages; and a second ladder resistor circuit including multiple second resistors connected to each other in series in at least one of an area between the first connection point and a power supply terminal to which a power supply voltage higher than the first reference voltage is supplied and an area between the second connection point and a grounding terminal to which a ground potential lower than the second reference voltage is supplied, and outputting at least one second divided voltage as the second reference voltage of the plurality of reference voltages are provided.