Condensing Lens Parallelizes Light for Curved Half Mirror in Head-Mounted Display
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Solution Overview
Problem
Head-mounted image display devices suffer from blurring due to non-parallel light reflection from curved half mirrors, resulting in deteriorated display quality.
Innovation Solution
Incorporating a condensing lens between the optical scanning section and the half mirror to convert the reflected light into parallel light, ensuring it is properly focused on the observer's retina, along with a design that optimizes the placement of optical components to reduce weight and enhance image clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a curved half mirror is used to reflect light from the scanning optical system, then the light path can be redirected to the observer's eye, but the reflected light becomes non-parallel causing image blurring
Solution Approach 1:
A condensing lens is introduced as an intermediary optical element between the scanning optical system and the curved half mirror. This lens condenses the parallel light from the scanning system before it reaches the curved mirror, and after reflection, converts the non-parallel reflected light back into parallel light, thereby eliminating the blurring effect while preserving the curved mirror's light redirecting function
Solution Approach 2:
The patent changes the optical parameter (parallelism) of the light beam through the condensing lens. By focusing and refocusing the light, the system transforms parallel incident light into a condensed beam that, upon reflection from the curved mirror, becomes parallel again, thus maintaining image clarity despite the curved reflection surface
2Volume of moving object
If optical components are positioned closer to the eye for compact design, then device size is reduced, but weight distribution becomes unbalanced affecting comfort
Solution Approach 1:
The patent redistributes optical components along the longitudinal axis (depth dimension) rather than only laterally. By placing the condensing lens and scanning system further forward on the nose bridge, the design achieves compact lateral profile while balancing weight distribution front-to-back, improving comfort without sacrificing compactness
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 significantly improves image clarity and reduces blurring, enabling a see-through type head-mounted display with enhanced display quality and weight balance.
Implementation Method 1
a condensing lens located on an optical axis between the optical scanning section and the half mirror and condensing the signal light from the optical scanning section between the optical scanning section and the half mirror to convert the signal light reflected by the half mirror into parallel light
Implementation Method 2
a half mirror located on a surface on which the signal light from the optical scanning section of the light transmitting section is made incident and having a curved surface that reflects the signal light from the optical scanning section
Data Source
AI summary
A head mounted image display device includes: a frame including a front section having a nose pad; a light transmitter supported by the front section and allowing visible light to pass therethrough; an optical scanner that receives signal light modulated according to an image signal and made incident thereon and that two-dimensionally scans the incident signal light toward the light transmitter; a half mirror on a surface on which the signal light from the optical scanner is incident and having a curved surface that reflects the signal light; and a condensing lens on an optical axis between the optical scanner and the half mirror and condensing the signal light from the optical scanner between the optical scanner and the half mirror to convert the signal light reflected by the half mirror into parallel light.