Display Driving Circuit Selective Voltage Boosting
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Solution Overview
Problem
Liquid-crystal display apparatuses face challenges in reducing power consumption while maintaining sufficient dynamic range for gradation display and optimizing both white and black luminance, with existing methods like 1H Vcom inversion driving and capacitive coupling driving experiencing issues such as large luminance variations and power consumption.
Innovation Solution
A liquid-crystal display apparatus with a voltage boosting function in the driving circuit that selectively enables or disables voltage boosting based on the gradation level, using a capacitive coupling effect only when necessary, and includes a monitor circuit to detect electric potentials and adjust the common voltage, optimizing the effective pixel electric potential.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If voltage boosting function is always enabled to ensure sufficient dynamic range for gradation display, then the dynamic range is improved, but power consumption increases
Solution Approach 1:
The voltage boosting function is dynamically controlled based on the input signal level. The driving circuit selectively enables voltage boosting only when the input voltage level is insufficient for proper liquid crystal cell operation, rather than continuously enabling it. This dynamic adaptation resolves the contradiction by providing sufficient dynamic range only when necessary, thereby reducing overall power consumption while maintaining gradation display precision.
Solution Approach 2:
The driving circuit changes the voltage parameter adaptively by detecting the input signal level and adjusting whether to apply voltage boosting. When the input voltage is above a threshold level, boosting is disabled; when below the threshold, boosting is enabled. This parameter change strategy ensures adequate dynamic range for gradation display while minimizing power consumption by avoiding unnecessary boosting operations.
2Device complexity
If 1H Vcom inversion driving method is used to simplify the driving scheme, then the device complexity is reduced, but luminance variations occur
Solution Approach 1:
The driving circuit incorporates feedback mechanisms that monitor the liquid crystal cell voltage and adjust the Vcom inversion timing and amplitude accordingly. This feedback control compensates for luminance variations that would otherwise occur with simple 1H Vcom inversion, allowing the system to maintain luminance stability while keeping the driving scheme relatively simple.
Solution Approach 2:
The driving circuit performs preliminary adjustments to the Vcom inversion parameters based on detected signal conditions before the actual display refresh occurs. By pre-adjusting the common voltage inversion characteristics, the system prevents luminance variations from occurring during the display cycle, thereby maintaining stability without requiring complex real-time correction circuits.
3Speed
If capacitive coupling driving is applied to improve response speed, then the speed is improved, but power consumption increases and luminance optimization becomes difficult
Solution Approach 1:
The capacitive coupling effect is applied partially rather than continuously. The driving circuit selectively activates capacitive coupling boosting only for specific voltage transitions or time periods when it provides the most benefit for response speed, rather than applying it excessively throughout the entire frame cycle. This partial application reduces power consumption while still achieving improved response speed where needed.
Solution Approach 2:
The capacitive coupling driving is implemented as a periodic action synchronized with the frame refresh rate and horizontal scan periods. By applying capacitive coupling effects at specific periodic intervals rather than continuously, the system achieves improved liquid crystal response speed during critical transition periods while minimizing overall power consumption during steady-state display periods.
4Use of energy by moving object
If voltage is reduced to lower power consumption, then power consumption is reduced, but dynamic range becomes insufficient for gradation display
Solution Approach 1:
The driving circuit dynamically adjusts the voltage level based on the input signal characteristics. When the input voltage is already sufficient, the circuit operates at reduced voltage to minimize power consumption. When the input voltage is too low to provide adequate dynamic range, the circuit automatically enables voltage boosting to restore sufficient voltage levels for proper gradation display. This dynamic voltage adjustment resolves the contradiction between power consumption and gradation precision.
Solution Approach 2:
The driving circuit changes the voltage parameter adaptively by monitoring input signal levels and selectively applying voltage boosting only when the input voltage falls below a threshold required for sufficient dynamic range. This parameter change strategy allows the system to operate at lower voltages (reducing power consumption) during normal conditions while automatically restoring adequate voltage levels (maintaining gradation precision) when needed.
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
The solution reduces power consumption, stabilizes luminance, and ensures optimal white and black luminance by dynamically adjusting the voltage boosting function and common voltage, addressing the limitations of existing methods.
Implementation Method 1
a voltage driving circuit having a voltage boosting function for carrying out a voltage boosting operation to boost an input voltage having a level with a dynamic range insufficient for a gradation expression
Data Source
AI summary
A display apparatus including: an effective pixel section having a plurality of pixel circuits arranged to form a matrix, each pixel circuit including a switching device through which pixel video data is written into the pixel circuit; a plurality of scan lines each provided for an individual one of rows of the pixel circuits arranged on the effective pixel section to control the conduction states of the switching devices; a plurality of capacitor lines each arranged for individual one of the rows connected to the pixel circuits; a plurality of signal lines each arranged for individual one of columns connected to the pixel circuits to propagate the pixel video data; a first driving circuit configured to selectively drive the scan lines and the capacitor lines; and a second driving circuit configured to drive the signal lines.