Light Guide Plate Positioning via Mechanical Interlock
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Solution Overview
Problem
Existing light-guide type display devices face challenges in maintaining image quality due to temperature-induced expansion or contraction of the light guide plate, particularly when using buffers with low elastic modulus, which can lead to complex equipment and longer processing times, as well as difficulties in conforming to shape changes.
Innovation Solution
A light-guide type display device with a light guide plate featuring a first opening section and a second opening section of different shapes, aligned parallel to each other, and supported by fixing members on a support member, allowing for secure positioning without adhesives, enabling expansion and contraction while maintaining image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a buffer with low elastic modulus is used to fix the light guide plate to the support member, then the light guide plate can conform to expansion and contraction due to temperature change, but the bonding process becomes complex and takt time increases
Solution Approach 1:
The invention extracts and eliminates the buffer (adhesive) component from the bonding process. By using a mechanical fixation structure with protrusions fitting into recesses, the patent removes the need for complex adhesive application processes, curing equipment, and associated process controls, thereby simplifying the bonding process while maintaining the ability to accommodate thermal expansion
Solution Approach 2:
The invention replaces the chemical bonding mechanism (adhesive) with a mechanical bonding mechanism (protrusions and recesses). This substitution eliminates the need for adhesive application equipment, curing processes, and quality control for adhesive bonding, significantly simplifying the overall bonding process and reducing takt time
2Stress or pressure
If a soft buffer is used to reduce stress on the light guide plate during temperature change, then stress is reduced, but the buffer has low viscosity before curing and is likely to squeeze out, making the bonding process difficult
Solution Approach 1:
The invention removes the buffer material entirely from the system, replacing it with a mechanical interlocking structure. This eliminates the conflicting requirements of needing both low viscosity (for application) and high viscosity (to prevent squeezing out), as well as the need for curing processes
Solution Approach 2:
The protrusions and recesses provide a permanent, reusable mechanical connection that does not rely on consumable materials like adhesive. The structure itself serves as the bonding mechanism, eliminating the need for separate bonding materials
3Strength
If a rigid support member is used to support the light guide plate, then structural support is provided, but the difference in linear expansion coefficient between the rigid support member and the light guide plate makes it difficult to conform to shape changes
Solution Approach 1:
The invention segments the connection interface into discrete protrusions and recesses rather than using a continuous rigid connection. This segmentation allows localized movement and deformation at the interface while maintaining overall structural support, enabling the system to accommodate differential thermal expansion between the rigid support member and the light guide plate
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 solution simplifies the bonding process, reduces takt time, and enhances reliability in maintaining image quality by allowing the light guide plate to expand or contract without deflection, thus addressing the degradation issues associated with temperature changes.
Implementation Method 1
if the light guide plate as described above expands or contracts due to a temperature change
Data Source
AI summary
A light-guide type display device that includes a light guide plate that optically guides an image to a pupil of a viewer, and a support member that supports the light guide plate and is provided with two fixing members. The light guide plate includes a first opening section that has a first opening having a long axis and a short axis, and a second opening section that has a second opening having a shape different from that of the first opening and located on a line that passes through the first opening section and that is parallel to a long-axis direction of the first opening section. Each of the two fixing members is inserted into a corresponding one of the first opening section and the second opening section.