Image Display Apparatus Dither Signal Generation for Gradation Levels
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Panel-type image display apparatuses, such as LCDs and PDPs, face challenges in achieving enhanced gradation levels without increasing the number of subframes within one frame, as higher operating frequencies lead to excess heat and reduced intensity, making it difficult to meet the demand for multi-gradation.
Innovation Solution
The solution involves a dither signal generating circuit that adds dither signals to pixel data to enhance gradation levels, combined with a subframe generating circuit that divides the frame into subframes, and a column-signal and row-scanning-signal electrode drive circuit with shift registers to manage data transfer and voltage levels, allowing for increased representable gradation levels without increasing the number of subframes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of subframes is increased to achieve multi-gradation, then representable gradation levels are enhanced, but operating frequency increases causing excess heat and reduced intensity
Solution Approach 1:
The invention divides the display panel into multiple groups of pixels (e.g., 4 groups) and assigns different subframe combinations to each group. This segmentation allows the system to achieve higher effective gradation levels (e.g., 320 levels) by combining the output of multiple pixel groups, rather than increasing the number of subframes for the entire panel. Each pixel group uses a subset of subframes, keeping the operating frequency manageable while the combined output provides enhanced gradation precision.
Solution Approach 2:
The invention transitions from a single-dimension approach (increasing subframe count) to a multi-dimensional approach by organizing pixels into multiple groups that are driven by different subframe combinations. The gradation information is distributed across multiple pixel groups and time periods, effectively adding spatial and temporal dimensions to the gradation encoding process. This allows achieving 320 gradation levels through the combination of 4 pixel groups with 80 levels each, without proportionally increasing the subframe count for the entire system.
2Manufacturing precision
If the number of subframes is increased to achieve multi-gradation, then representable gradation levels are enhanced, but operating frequency increases causing design modifications
Solution Approach 1:
The display panel is divided into multiple pixel groups (e.g., 4 groups), each driven by a different combination of subframes. This segmentation allows the use of existing subframe structures without modification, while achieving enhanced gradation through the combination of multiple pixel group outputs. The drive circuits are configured to apply different subframe sequences to different pixel groups, avoiding the need to redesign the basic operating frequency and subframe timing.
Solution Approach 2:
The invention makes the pixel groups serve multiple functions: each pixel group not only displays image data but also contributes to the overall gradation precision when combined with other pixel groups. The same subframe structure and drive circuitry are reused across different pixel groups with different configurations, achieving multi-gradation capability without requiring fundamentally different design elements for each pixel group.
3Manufacturing precision
If the number of subframes is increased to achieve multi-gradation, then representable gradation levels are enhanced, but intensity is reduced
Solution Approach 1:
By dividing the panel into multiple pixel groups that are active during different subframe combinations, the invention ensures that each pixel group operates during sufficient time periods to accumulate adequate light output. The segmentation allows each pixel group to maintain its intensity while the temporal and spatial combination of multiple groups achieves the enhanced gradation precision, avoiding the intensity reduction that would occur if a single set of pixels operated during all subframes.
Solution Approach 2:
The invention adds spatial dimension (multiple pixel groups) to compensate for the temporal distribution of subframes. Instead of relying solely on time-division multiplexing which reduces intensity per pixel, the system uses both time and space dimensions: multiple pixel groups are activated at different times and combined, maintaining adequate intensity contribution from each group while achieving high gradation precision through their combination.
Data Source
AI summary
An image display apparatus that has a display section provided with a first plurality of pixels arranged in a matrix. Sequentially generated are dither signals each formed in a matrix of P rows×Q columns (P and Q being both positive integers and at least either one being 2 or more) corresponding to a second plurality of pixels that are a part of the first plurality of pixels in the display section, in order to enhance the gradation levels of a first image signal. The dither signals are sequentially added to the pixel data of the first image signal, thus a second image signal being output with enhanced gradation levels. One frame of the second image signal is divided into a plurality of subframes, thus a subframe signal being generated. Data per line carried by the subframe signal is sequentially supplied to column-signal electrodes connected to the pixels of the display section. Data per line carried by the subframe signal is sequentially supplied to pixels of rows corresponding to respective lines. The first plurality of pixels of the display section are grouped in the same unit of group as the second plurality of pixels. The display section is driven to display pixel data of each of the second plurality of pixels in each group for each of display periods provided in the same number as the second plurality.