Field Sequential Color Display Driving With Delta-Sigma Modulation
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Solution Overview
Problem
Current display technologies, such as OLEDs and LCDs, face challenges in energy efficiency, manufacturing complexity, color uniformity, and power consumption, particularly in emissive and non-emissive displays, which hinder their ability to produce bright, clear, and colorful images while minimizing energy usage.
Innovation Solution
The implementation of a Field Sequential Color (FSC) system using Delta Sigma (ΔΣ) Pulse Density Modulation (PDM) in display drivers, which converts incoming video/images into sequential mono-colored frames perceived as a full color frame by the human eye, reducing power consumption and improving contrast and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If OLEDs are used for display, then deep black level and high contrast are achieved, but manufacturing complexity and difficulty increase significantly
Solution Approach 1:
The patent replaces the emissive OLED mechanism with a non-emissive LCD system using Field Sequential Color (FSC) technology. Instead of using complex organic light-emitting diodes with multiple thin film stacks, the invention uses a simplified LCD structure with a single color filter that sequentially displays red, green, and blue frames. This substitution eliminates the need for complex vacuum deposition processes and multiple organic layers while maintaining high contrast and deep black levels through the liquid crystal shuttering effect.
Solution Approach 2:
The patent implements Field Sequential Color (FSC) technology that periodically displays monochromatic frames in sequence (red, green, blue) at high frame rates. The liquid crystal layer acts as a shutter that opens and closes periodically for each color channel, allowing the backlight to illuminate only during the appropriate color phase. This periodic action creates the perception of full-color images while using a simplified single-color-filter structure, thereby reducing manufacturing complexity while maintaining OLED-like contrast performance.
2Ease of manufacture
If LCDs are used for display, then ease of manufacture and modularity are improved, but energy efficiency and light utilization deteriorate
Solution Approach 1:
The patent uses Field Sequential Color (FSC) technology that periodically activates the backlight only during the time when liquid crystal pixels are in the on-state for each color channel. By synchronizing the backlight illumination with the liquid crystal switching cycles, the system eliminates continuous backlight operation, thereby significantly reducing power consumption while maintaining the simplicity and manufacturability of LCD structures.
Solution Approach 2:
The patent ensures that the backlight operates continuously only when needed - specifically, during the brief intervals when liquid crystal pixels are switched to the on-state for each color channel. This continuous-but-synchronized operation eliminates wasted illumination during pixel off-states, maximizing light utilization efficiency while maintaining the ease of manufacture and modular architecture inherent in LCD technology.
3Ease of manufacture
If color filters are used in LCDs, then color display is achieved, but light loss and efficiency deteriorate
Solution Approach 1:
The patent segments the color display function into separate temporal channels using Field Sequential Color (FSC) technology. Instead of using a single color filter array that blocks 60% of light, the invention uses a single color filter per subpixel that is activated sequentially for red, green, and blue channels. Each monochromatic frame uses only the corresponding color filter, allowing that specific wavelength to pass through with minimal loss, thereby dramatically improving light efficiency while maintaining full-color display capability.
4Reliability
If TFTs are increased per pixel for stable current control, then device stability is improved, but aperture ratio and light transmission deteriorate
Solution Approach 1:
The patent replaces the OLED current-driven mechanism with a voltage-driven LCD system. Instead of requiring 3-6 thin film transistors per pixel for stable current control in OLEDs, the invention uses a simplified voltage control scheme where liquid crystal pixels respond to voltage changes that orient the crystals to control light transmission. This substitution dramatically reduces the number of TFTs required per pixel, thereby increasing the aperture ratio and improving light transmission while maintaining device stability through voltage-based control.
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 eliminates color breakup, increases color saturation, enhances contrast, and reduces power consumption by up to 7.5 times, while increasing pixel density and brightness, thereby addressing the inefficiencies of traditional display technologies.
Implementation Method 1
The human eye uses temporal integration to blend as shown in FIG. 8
Data Source
AI summary
A device and method of an image processing system where a Field Sequential Color Delta Sigma Pulse Density Modulation is used for digital displays, where the digital displays are non-emissive. The device and method are a digital driving solution using Delta Sigma Encoding where N bit-per-component symbols at F1 frame-rate-per-second are represented using M bits-per-component symbols at F2 frame-rate-per-second, where N≥M and F2≥F1. The F2 frames are sent to a sequential color picker, which outputs frames with one color, followed by the next in a sequential pattern which reduces power consumption, increases color saturation, increases contrast, and increases brightness.