Virtual Image Display Device Bonding Strength
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual image display devices face challenges in increasing display size and effective pupil diameter due to the use of small light guide optical systems, leading to blind areas and insufficient see-through capabilities.
Innovation Solution
A virtual image display device with a light guide member and a semi-transmissive reflecting film on a partial area of the junction surface, bonded to a light transmitting member with a nonsmooth surface, enhancing bonding strength and allowing for increased display size and see-through capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light guide optical system with an emission opening smaller than the pupil is used to realize see-through property, then the see-through capability is improved, but the display size of virtual image and effective pupil diameter cannot be increased
Solution Approach 1:
The optical system is divided into multiple light guide members (first light guide member and second light guide member) with different functions. The first light guide member handles virtual image light with a larger emission opening to increase display size, while the second light guide member handles external light with a smaller emission opening to maintain see-through capability. This segmentation allows both requirements to be satisfied simultaneously.
2Ease of manufacture
If a light guide optical system with an emission opening smaller than the pupil is used, then see-through property is achieved, but effective pupil diameter cannot be increased to correspond to individual human pupil distance
Solution Approach 1:
The system separates the pupil accommodation function into the second light guide member, which has an emission opening sized to match individual pupil distances. This member can be independently adjusted or replaced to accommodate different users, while the first light guide member provides the larger display size.
3Volume of moving object
If the emission opening and housing of the light guide optical system are arranged in the physical vicinity of the pupil, then compact design is achieved, but a blind area is caused and perfect see-through state cannot be realized
Solution Approach 1:
The system uses two separate light guide members positioned at different locations. The first light guide member is positioned for virtual image display while the second light guide member is positioned to provide an unobstructed view of external light. This eliminates the blind area problem while maintaining compact overall design.
4Ease of manufacture
If a half mirror is attached to the light guide member and a prism-like member is attached to bury the half mirror inside, then the system is modified into a see-through light guide device, but strong force is applied to the bonding part and exfoliation may occur if bonding strength is insufficient
Solution Approach 1:
Instead of attaching multiple components (half mirror and prism-like member) to a single light guide member, the invention divides the system into two separate light guide members that are integrated from the beginning. This eliminates the bonding interfaces that would be subject to strong forces, as the members work together as a unified optical system.
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 solution increases the bonding strength between the light guide and transmitting members, improving the display size and see-through properties by ensuring sufficient attachment force and minimizing light disturbance, while maintaining accurate observation of external light.
Implementation Method 1
a light guide section adapted to guide the image light taken in from the light entrance section using total reflection by a first surface and a second surface opposed to each other
Implementation Method 2
bonded to the first junction surface with an adhesive in at least the exceptional area
Data Source
AI summary
A virtual image display device has a light guide device in which the half mirror layer (the semi-transmissive reflecting film) of the light guide member is formed on the partial area of the first junction surface, and the second junction surface of the light transmitting member is bonded to the first junction surface in at least the exceptional area. Therefore, it is possible to increase the bonding strength of the first junction surface and the second junction surface, namely the strength of the light guide device composed of the light guide member and the light transmitting member combined with each other even in the case in which the attachment force of the half mirror layer (the semi-transmissive reflecting film) with respect to the first junction surface is not sufficiently strong.