Image Display Apparatus Optical Path for HMD Frame Integration
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Solution Overview
Problem
Existing head-mounted displays (HMDs) face limitations in design flexibility and risk of image displacement when viewing horizontally located objects, as the image display apparatus is typically positioned below the observer's line of sight, restricting tilt angles and freedom of movement, which can lead to the image being moved away from the eyes during vertical pivoting.
Innovation Solution
The central light beam intersects the XY plane at an angle other than 0 degrees, allowing for a higher degree of freedom in attaching the image display apparatus to a frame-shaped glasses and enabling pivotal attachment with a virtual straight line connecting the eyeballs as a pivot axis, thereby preventing image displacement during vertical movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the image display apparatus is positioned below the observer's line of sight, then the apparatus can be attached to frame-shaped glasses, but the tilt angle is restricted and design freedom is limited
Solution Approach 1:
The patent changes the optical path orientation from the conventional horizontal plane to a vertical plane by making the central light beam intersect the XY plane at an angle other than 0 degrees. This dimensional change allows the image display apparatus to be positioned in front of the observer's line of sight rather than below it, thereby increasing design freedom and tilt angle while maintaining attachability to frame-shaped glasses.
2Reliability
If the image display apparatus is positioned below the line of sight, then it can be attached to glasses, but the image may be moved away from the eyes during vertical pivoting
Solution Approach 1:
By reorienting the optical path to intersect the XY plane at an angle other than 0 degrees, the patent positions the image display apparatus in front of the observer's line of sight. This configuration ensures that during vertical pivoting movements, the image remains stable within the observer's field of view while allowing greater freedom of movement, resolving the contradiction between image stability and adaptability.
3Adaptability or versatility
If the central light beam intersects the XY plane at an angle other than 0 degrees, then design flexibility is enhanced, but the optical system becomes more complex
Solution Approach 1:
The patent changes the angular parameter of the central light beam intersection with the XY plane from 0 degrees to an angle other than 0 degrees. This parameter change enhances design flexibility and allows the image display apparatus to be positioned in front of the observer's line of sight. The optical system complexity is managed by using standard optical components arranged in this new configuration, demonstrating that parameter changes can achieve design goals without necessarily increasing overall system 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
This configuration enhances design flexibility and maintains the image within the observer's field of view, reducing the risk of image displacement and allowing for a wider range of attachment angles without obstructing the horizontal line of sight.
Implementation Method 1
a collimating optical system which converts light emitted from the image forming device into parallel light
Implementation Method 2
the parallel light is incident on and is emitted from a first surface of the light guide plate. The parallel light propagates in the light guide plate by total reflection
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
An image display apparatus includes: an image forming device; an optical system converting light emitted from the image forming device into parallel light; and an optical device to which the light beams converted into the parallel light by the optical system enter, in which the light beams are guided, and from which the light beams are emitted, wherein a central light beam emitted from the center of the image forming device, passing through the nodal point of the optical system and entering the optical device at an optical device center point intersects an XY plane defined by an X axis that passes through the optical device center point, and is parallel to the axis direction of the optical device and a Y axis that passes through the optical device center point, and coincides with the normal axis of the optical device at angles other than 0 degree.