Common Light Path Region for Mixed Reality Display Weight Reduction
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Solution Overview
Problem
In mixed reality display devices, achieving desired illumination and image quality is challenging due to the need for differential treatment of illumination and image light, which is difficult to implement in compact, low-weight form factors like head-mounted displays using separate optical paths.
Innovation Solution
A display device with a common light path region using a beam splitter cube, where illumination and image light share the same path and are treated by optical elements within this region to achieve uniform illumination and focused imaging, reducing the need for separate optical channels and minimizing size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate optical paths are used for illumination light and image light, then differential treatment of the two light types can be achieved, but the device size and weight increase
Solution Approach 1:
The patent merges the illumination path and imaging path into a common light path region, allowing both illumination light and image light to share the same optical path. This consolidation eliminates the need for separate optical channels, thereby reducing device size and weight while maintaining the ability to differentially treat the two light types through wavelength-selective optical elements positioned at specific locations within the common path.
Solution Approach 2:
The patent segments the common light path into distinct functional regions: an illumination path portion for transporting illumination light to the spatial light modulator, and an imaging path portion for transporting modulated image light to the eye. By spatially separating these functions within the common path and using wavelength-selective elements to direct different light types to their respective destinations, the system achieves differential treatment without requiring completely separate optical paths.
2Ease of manufacture
If separate optical paths are used for illumination light and image light, then differential treatment of the two light types can be achieved, but the device complexity increases
Solution Approach 1:
The patent consolidates the illumination and imaging paths into a single common light path region, reducing the number of separate optical channels from two to one. This merging simplifies the overall optical architecture by eliminating redundant path separations while maintaining functional differentiation through strategically placed wavelength-selective optical elements that direct different wavelengths to their appropriate destinations within the same physical path.
3Weight of moving object
If compact form factor is achieved by using common light path region, then device size and weight are reduced, but differential treatment of illumination and image light becomes difficult
Solution Approach 1:
The patent applies local quality by positioning wavelength-selective optical elements at specific locations within the common light path region. These elements have localized functions: they selectively reflect or transmit specific wavelength ranges at particular points along the common path, enabling differential treatment of illumination and image light without requiring separate optical channels. This localized functional differentiation allows compact design while maintaining the ability to independently control each light type.
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 approach enables compact and lightweight mixed reality display devices by consolidating illumination and imaging paths, ensuring uniform illumination and suppressing ghost imagery while maintaining image quality.
Implementation Method 1
A display device with a common light path region using a beam splitter cube, where illumination and image light share the same path and are treated by optical elements within this region
Data Source
AI summary
Examples are disclosed that relate to display devices having a common light path region. One example provides a display device comprising a light source configured to emit illumination light along an illumination path, and a spatial light modulator configured to modulate the illumination light and emit the modulated illumination light as image light along an imaging path, wherein at least a portion of the illumination path and at least a portion of the imaging path extend through a common light path region. The display device further comprises one or more optical elements positioned within the common light path region, at least one optical element being configured to guide the illumination light as the illumination light travels through the common light path region toward the spatial light modulator, and shape the image light as the image light travels through the common light path region.