High-Resolution VR LCD Spacer Structure for Reduced Mura
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Solution Overview
Problem
Existing high-resolution liquid crystal displays (LCDs) in near-eye displays face issues such as photo spacer mura, screen-door effect, ghosting, and latency, which degrade visual quality and user experience in virtual reality (VR) applications.
Innovation Solution
Implementing smaller photo spacers with larger heights, adjusting the sub-spacer and photo spacer ratio, using liquid crystals with low viscosity and high birefringence, and optimizing backlight timing to reduce mura and ghosting, while increasing pixel per inch (PPI) and refresh rate to mitigate the screen-door effect and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photo spacers are made smaller with larger heights, then mura is reduced, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The spacer structure is divided into two functional parts: a broad base portion for stable mounting on the substrate and a narrower vertical portion for defining the cell gap. This segmentation allows each part to be optimized independently - the base provides manufacturing stability while the vertical portion achieves the desired compact height ratio for reducing mura.
Solution Approach 2:
Different portions of the spacer have different geometric properties tailored to their specific functions. The base portion has larger lateral dimensions for stable attachment and ease of fabrication, while the vertical portion has smaller lateral size to minimize light blocking and reduce mura effects in the display region.
2Manufacturing precision
If pixel per inch (PPI) is increased, then screen-door effect is reduced, but device complexity increases
Solution Approach 1:
The invention optimizes the geometric parameters of the spacer structure (base width, vertical height, lateral dimensions) to achieve the desired cell gap with minimal impact on the overall pixel structure. This parameter optimization enables higher PPI displays without proportionally increasing manufacturing complexity by making the spacer itself more complex.
3Loss of time
If refresh rate is increased, then latency is reduced, but use of energy increases
Solution Approach 1:
The backlight operates in periodic pulses synchronized with the display refresh rate rather than continuously. By optimizing the pulse timing and duration, the system achieves low latency response for motion tracking while reducing overall energy consumption through duty cycling the backlight operation.
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
Enhances visual quality by reducing mura, ghosting, and latency, and improves color gamut, resulting in a more immersive VR experience.
Implementation Method 1
a liquid crystal display (LCD) of a near-eye display may include a first substrate, a second substrate, a plurality of photo spacers formed on the second substrate, a plurality of sub-spacers formed on the first substrate, and a liquid crystal material in regions between the first substrate and the second substrate
Implementation Method 2
Each sub-spacer of the plurality of sub-spacers is configured to support a corresponding photo spacer of the plurality of photo spacers
Data Source
AI summary
A liquid crystal display (LCD) of a near-eye display includes a first substrate, a second substrate, a plurality of photo spacers formed on the second substrate, a plurality of sub-spacers formed on the first substrate, and a liquid crystal material in regions between the first substrate and the second substrate. Each sub-spacer of the plurality of sub-spacers is configured to support a corresponding photo spacer of the plurality of photo spacers. A resolution of the LCD is greater than 800 pixels per inch. Each photo spacer of the plurality of photo spacers has a smaller lateral size and a larger height than the corresponding sub-spacer of the plurality of photo spacers.