Wearable Display Thermal Insulation via Segmented Air Gaps
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Solution Overview
Problem
Head-Mounted Display (HMD) devices using organic electroluminescence (EL) elements generate significant heat due to current flow, leading to temperature rises that can discomfort users and impair the fit feeling during wear.
Innovation Solution
Incorporating a thermal insulation space filled with air between the display unit and the contact surface, which reduces heat transfer and maintains comfort by preventing temperature rise at the contact surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the display unit is placed close to the contact surface to reduce device size, then the HMD becomes smaller and lighter, but heat generated by the display unit transfers to the contact surface causing temperature rise and discomfort
Solution Approach 1:
The case is divided into multiple walls (first wall, second wall, third wall) creating segmented spaces between them. These spaces are filled with air, which has low thermal conductivity, thereby segmenting the heat transfer path and reducing heat transfer to the contact surface while maintaining compact device size.
Solution Approach 2:
Air spaces filled between the walls serve as thermal insulation intermediaries. The air in the spaces acts as a mediator that blocks heat transfer from the display unit to the contact surface, reducing thermal conduction while allowing the display unit to remain close to the contact surface for compact design.
2Ease of operation
If the display unit is placed close to the contact surface to improve fit feeling, then the HMD provides better comfort, but heat generated by the display unit transfers to the contact surface causing temperature rise and discomfort
Solution Approach 1:
The case structure is segmented into multiple walls with air-filled spaces between them. This segmentation creates thermal insulation barriers that allow the display unit to be positioned close to the contact surface for good fit feeling while preventing heat transfer to the contact surface.
Solution Approach 2:
Air spaces act as thermal insulation intermediaries between the display unit and the contact surface. These air-filled spaces maintain close contact for comfort while blocking heat transfer, thus preserving fit feeling without causing thermal discomfort.
3Temperature
If the case includes multiple walls with air spaces to reduce heat transfer, then thermal insulation is improved, but the device structure becomes more complex
Solution Approach 1:
The multiple walls in the case serve multiple functions simultaneously: they provide structural support for the HMD, create air-filled thermal insulation spaces, and define the overall device geometry. This multi-functionality reduces the need for separate insulation components, thereby limiting the increase in structural complexity.
Solution Approach 2:
The case walls are merged with the insulation function by filling the spaces between walls with air. This combining of structural and insulation functions in a single integrated design avoids the need for additional separate insulation layers or components, thus limiting the increase in device complexity.
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 effectively suppresses discomfort caused by heat generation in HMD devices, ensuring comfort and maintaining a secure fit by minimizing heat transfer to the contact surface.
Implementation Method 1
The space is an area filled with air, and is an excellent thermal insulation area which does not transfer (propagate) heat easily compared to solids or liquids
Implementation Method 2
the organic EL elements generate heat due to the current which flows between the anode and the cathode
Data Source
AI summary
There is provided an electro-optical apparatus which is wearable on a human body, including: a display unit that includes pixels and a drive circuit which drives the pixel; and an case that contains the display unit and includes a contact surface which comes into contact with the human body. The contact surface is arranged to have at least one space from the display unit.