Optical Module Barrel Positioning for HMD Alignment
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Solution Overview
Problem
Existing head-mounted display apparatuses that allow observation of virtual images face challenges in maintaining accurate alignment between prisms, leading to position shifts and potential degradation of optical performance.
Innovation Solution
The optical module includes an image element, a first reflection member with an incident, emission, and reflection portion, a second reflection member that reflects image light towards a pupil position, and a supporting member with limiting and positioning portions to accurately position the first reflection member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If protrusions and recesses are used for coupling prisms, then assembly alignment is facilitated, but gaps are formed causing position shift and reduced manufacturing precision
Solution Approach 1:
A supporting member is introduced as an intermediary component between the first and second prisms. This supporting member includes positioning portions that contact specific surfaces of both prisms, mediating their relative positioning. The supporting member acts as a mediator that eliminates the need for direct prism-to-prism coupling via protrusions and recesses, thereby preventing gap formation while maintaining assembly facilitation.
Solution Approach 2:
The invention replaces the mechanical protrusion-recess coupling system with a surface-contact positioning system. Instead of using interlocking mechanical features that create gaps, the supporting member uses flat surface contacts (first and second positioning portions) to establish precise positional relationships. This substitution of the mechanical coupling mechanism eliminates the gap problem while maintaining ease of assembly.
2Stability of the object's composition
If multiple coupling portions are used to suppress position shift, then assembly stability is improved, but the complexity of the assembly structure increases
Solution Approach 1:
The supporting member merges multiple positioning functions into a single integrated component. Instead of having separate coupling portions on each prism, the supporting member combines the functions of positioning the first prism, positioning the second prism, and maintaining their relative alignment all in one structure. This merging reduces the number of discrete coupling features needed while maintaining assembly stability.
Solution Approach 2:
The supporting member serves multiple functions simultaneously: it supports the weight of the prisms, positions them accurately in three-dimensional space, maintains their relative alignment, and facilitates assembly. This multi-functionality reduces the need for separate specialized coupling mechanisms, thereby reducing overall structural complexity while improving stability.
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 minimizes position shifts and maintains high optical performance by precisely aligning the optical components, ensuring accurate image projection and reduced aberrations.
Implementation Method 1
a first reflection member that includes: an incident portion on which the image light is incident, an emission portion that emits the image light, and a reflection portion that reflects the image light from the incident portion toward the emission portion
Implementation Method 2
a second reflection member that reflects the image light from the first reflection member toward a pupil position
Data Source
AI summary
An optical module includes: an image element; a prism mirror that reflects image light emitted from the image element at an inner reflection portion; a combiner that reflects the image light from the prism mirror toward a pupil position; and a barrel that is disposed between the prism mirror and the combiner and that positions the prism mirror. The barrel includes a first positioning surface brought into contact with the prism mirror in a second direction perpendicular to a first imaginary plane and parallel to a normal line of a second imaginary plane on which the image light emitted from an emission portion of the prism mirror is incident, and a second positioning portions brought into contact with the prism mirror in a third direction perpendicular to the first direction and intersecting the second direction.