3D LCD Black Insertion Pattern for Afterimage Uniformity

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Solution Overview

Problem

In time-division type 3D liquid crystal display devices, black insertion methods lead to uneven afterimage production, primarily affecting the left eye images, resulting in noticeable afterimages due to continuous pixel display across frames.

Innovation Solution

An image display method where black insertion is applied to basic regions of a liquid crystal panel with varying patterns, ensuring each pixel is subjected to black insertion equally across multiple frames, uniformly distributing afterimages over space and time to reduce their visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If black images are inserted between left eye and right eye divided images to reduce cross-talk, then cross-talk is reduced, but the frame rate considerably degrades

Engineering Contradiction:
Improvecross-talkVSAvoidframe rate
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent divides the black image into multiple black segments that are distributed across different frame periods. Instead of inserting one complete black frame between left and right eye images, the black image is segmented and inserted in parts during the display periods of divided images, thereby reducing the impact on frame rate while maintaining cross-talk suppression

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies partial black insertion rather than complete black frame insertion. By inserting only portions of black images at specific positions within frame periods, the solution achieves sufficient cross-talk reduction without the excessive action of complete frame-rate degradation

Inventive Principle:
Principle #16Partial or excessive action

2Object-affected harmful factors

If black insertion is applied to reduce cross-talk, then cross-talk is reduced, but uneven afterimages are produced primarily affecting left eye images

Engineering Contradiction:
Improvecross-talkVSAvoidafterimages
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent applies different black insertion patterns to different regions and eye images. Specifically, it controls the number and positioning of black segments differently for left eye and right eye images, ensuring that afterimages are uniformly distributed across both eyes rather than concentrated in one

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent uses asymmetric black insertion strategies for left and right eye images. By recognizing that left eye images suffer more from afterimages, it applies tailored black segment distributions that compensate for this asymmetry, achieving uniform afterimage appearance across both eyes

Inventive Principle:
Principle #4Asymmetry

3Object-affected harmful factors

If the frame rate is increased by dividing images to reduce cross-talk, then cross-talk is reduced, but afterimages become more noticeable due to continuous pixel display

Engineering Contradiction:
Improvecross-talkVSAvoidafterimages
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent implements periodic black segment insertion within the high frame rate structure. By rhythmically inserting black segments at specific intervals and positions within the divided image sequences, it creates periodic resets that prevent continuous pixel display effects, thereby reducing afterimages while maintaining the high frame rate structure

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2642477B1Video display method and liquid-crystal display device employing same
Publication Date: 2017.12.13 EIZO CORP
  • EP2642477B1 patent drawingFigure 1
  • EP2642477B1 patent drawingFigure 2(a)~2(e)
  • EP2642477B1 patent drawingFigure 3

AI summary

It is an objective to uniformize afterimages caused by black insertion to each image when two types of images are alternately displayed. There are provided a left and right image alternate output unit (15), a mask pattern storage unit (18), a mask pattern selection counter (17), and a mask synthesizing unit (16). The left and right image alternate output unit (15) alternately outputs two types of video frames. The mask pattern storage unit (18) stores m mask patterns, wherein basic regions are defined in a pixel region of a liquid crystal panel, the pixel region has m pixels arrayed in a matrix, m is an even number equal to or greater than 4, the m mask patterns have different arrangements of mask pixels in the basic region, and the number of the mask pixels is an even number smaller than m and equal to or greater than 2. The mask pattern selection counter (17) sequentially selects each of the mask patterns. The mask synthesizing unit (16) synthesizes the selected mask pattern on the video frame outputted from the alternate output unit. Each of the pixels in the basic region is replaced by the mask pixel by the same number of times throughout the m mask patterns.