Field Sequential Color Display Pixel Subdivision for Gradation Quality
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Solution Overview
Problem
Field sequential color image display devices face challenges in maintaining high-quality gradation display when increasing the field frequency to reduce color breaking, as the response speed of micromirrors limits the expression of the least significant bit and decreases the number of gradations.
Innovation Solution
The implementation of an image display device that uses pixel combinations formed by multiple pixels as units, allowing individual control of the ON and OFF states of each pixel, combined with pulse-width modulation (PWM) to achieve higher gradation display quality by varying the luminance of pixel combinations and extending subfield intervals, thereby increasing the subfield frequency without being constrained by micromirror response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the subfield frequency is raised to reduce color breaking, then color breaking is reduced, but the micromirror response speed cannot keep up and the least significant bit cannot be expressed
Solution Approach 1:
The patent divides a pixel into multiple subpixels (e.g., 2x2=4 subpixels) that are controlled independently. By segmenting the pixel control into multiple controllable units, the system can achieve finer gradation levels (11 bits or more) even at high subfield frequencies, resolving the contradiction between reducing color breaking and maintaining gradation quality
Solution Approach 2:
The patent dynamically adjusts the control strategy based on the subfield frequency and micromirror response characteristics. By making the pixel control dynamic (switching between different subpixel activation patterns), the system optimizes both color breaking reduction and gradation expression across different operating conditions
2Object-affected harmful factors
If the subfield frequency is raised to reduce color breaking, then color breaking is reduced, but the number of gradations decreases
Solution Approach 1:
By segmenting each pixel into multiple independently controllable subpixels, the patent increases the number of possible ON/OFF combinations. This segmentation enables 11 bits or more of gradation expression (2048 or more levels) even when operating at high subfield frequencies that would normally limit gradation capability
Solution Approach 2:
The patent adds a spatial dimension to the temporal modulation approach by controlling multiple subpixels within each pixel. This dimensional expansion from single-pixel temporal control to multi-subpixel spatial-temporal control enables higher gradation levels without being constrained by micromirror response speed
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 enables the maintenance or improvement of gradation display quality while significantly reducing color breaking, allowing for higher subfield frequencies and increased gradation expression, such as 11 bits or more, even when the field frequency is raised.
Implementation Method 1
The micromirrors are configured such that the angle of each changes in accordance with the drive voltage, the reflection angle differing when a drive voltage that indicates the ON state is supplied and when a drive voltage that indicates the OFF state is supplied
Implementation Method 2
The color wheel has a wheel unit that is provided with a red filter region, a green filter region, and a blue filter region, and is configured such that by rotating this wheel, white light from the light source sequentially irradiates each color filter region to sequentially emit red (R) light, green (G) light, and blue (B) light
Data Source
AI summary
An image display device includes: a light source unit that sequentially supplies light of a plurality of colors; an image formation unit that is provided with a pixel region that is made up of a plurality of pixels, light of a plurality of colors supplied by the light source unit sequentially irradiating the pixel region, and images of a plurality of colors being sequentially formed by the modulation of the incident light by each of the pixels; and a controller that controls the image-forming operation of the image formation unit. The controller causes formation of images of at least one color among the plurality of colors with pixel combinations made up of a plurality of pixels as pixel units and individually controls each pixel that make up the pixel combinations.