Virtual-Image Display Device Light Transmitting Structure
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Solution Overview
Problem
The existing virtual-image display devices face challenges in securing strong bonding between the coupling member and the light guiding unit due to the use of photocurable-type adhesives, especially when the coupling member is made of metal and shadows are created during curing, leading to incomplete curing.
Innovation Solution
A virtual-image display device is designed with a penetration-type fitting structure and a photocurable-type adhesive material placed between the attaching section and the support portion, where a light transmitting structure is formed to ensure sufficient curing of the adhesive.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photocurable-type adhesive is used to fix the coupling member and light guiding unit, then the number of processes is reduced and manufacturing flexibility is improved, but the adhesive remains in a half-cured or uncured state when the coupling member is made of metal and shadows are created for the curing light, leading to insufficient bonding strength
Solution Approach 1:
The attaching section is divided into multiple regions with different light transmissivity. A light transmitting structure (through-hole or slit) is formed in a specific region to allow curing light to reach the adhesive material in shadowed areas, while other regions maintain structural integrity. This segmentation enables complete curing of the adhesive without compromising the mechanical strength of the coupling member.
Solution Approach 2:
Different regions of the attaching section are assigned different optical properties. The light transmitting structure is strategically positioned to provide UV light transmission only where needed (in shadowed areas), while other areas maintain their metal properties for structural support. This local differentiation ensures complete adhesive curing in critical areas while preserving overall structural strength.
2Strength
If the coupling member is made of metal for structural strength, then the mechanical strength and rigidity are improved, but shadows are created during adhesive curing that prevent complete curing of the adhesive material
Solution Approach 1:
The metal attaching section is segmented to include a light transmitting structure (through-hole or slit) that allows UV curing light to penetrate through the metal to reach the adhesive material in shadowed areas. This segmentation enables the metal structure to maintain its strength while allowing complete adhesive curing.
Solution Approach 2:
The light transmitting structure acts as an intermediary element that bridges the gap between the UV light source and the adhesive material in shadowed areas. It allows UV light to pass through the metal coupling member to cure the adhesive, effectively mediating between the structural requirements of the metal and the curing requirements of the adhesive.
3Adaptability or versatility
If adhesive is used to fix the coupling member and light guiding unit, then adjustment flexibility is improved compared to screw fixing, but the adhesive may remain in a half-cured or uncured state leading to bonding strength issues
Solution Approach 1:
The attaching section is segmented with a light transmitting structure that enables complete curing of the adhesive material. This ensures that the adhesive achieves full bonding strength while maintaining the adjustment flexibility inherent in adhesive-based fixation, eliminating the trade-off between flexibility and strength.
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
The light transmitting structure allows for complete curing of the adhesive, enhancing the bonding strength between the coupling member and the light guiding unit, thereby improving the overall structural integrity and adjustment flexibility of the display device.
Implementation Method 1
a photocurable-type adhesive material put in between the attaching section and the support portion
Data Source
AI summary
A virtual-image display device includes: a first display unit including a first image element, a first projection optical system, and a first mirror; a second display unit including a second image element, a second projection optical system, and a second mirror; a coupling member configured to couple the first display unit and the second display unit; a penetration-type fitting structure formed at an attaching section and at a support portion, the attaching section being formed at the first display unit, the support portion being provided at the coupling member; and a photocurable-type adhesive material held between the attaching section and the support portion, in which an additional light transmitting structure is formed at one of the attaching section and the support portion, and the light transmitting structure is configured to cause light to reach a boundary region between the attaching section and the support portion.