Optical Expander Device Uniform Light Intensity Distribution
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Solution Overview
Problem
Existing optical expander devices suffer from uneven light intensity distribution and limited field of view due to the diffraction process, resulting in reduced image quality, especially in the corner regions of the output beam.
Innovation Solution
The expander device employs a waveguide plate with multiple diffraction elements and retrieval units to propagate light through different paths, ensuring that the output light is uniformly distributed across the waveguide region, thereby increasing the field of view and improving color uniformity by superimposing light from various paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the propagation path length is increased to expand the beam width, then the output beam width is improved, but the light intensity in corner regions decreases
Solution Approach 1:
The waveguide plate is divided into multiple propagation paths (first and second paths) with different lengths. The shorter first path delivers higher intensity light to corner regions, while the longer second path provides sufficient beam expansion. By segmenting the propagation paths, the patent simultaneously achieves wide beam output and uniform corner intensity distribution.
2Area of moving object
If multiple diffraction elements are used to expand the beam, then the beam expansion ratio is improved, but the light intensity is reduced
Solution Approach 1:
The beam expansion function is segmented across two separate propagation paths. The first path uses fewer diffraction elements for partial expansion, while the second path provides additional expansion. This segmentation allows the system to achieve high overall expansion ratio while maintaining higher light intensity by avoiding excessive diffraction losses in a single path.
Solution Approach 2:
The patent changes the parameter of propagation path length to optimize performance. By providing both shorter and longer propagation paths, the system can select appropriate path lengths for different regions, achieving optimal balance between beam expansion ratio and light intensity preservation.
3Device complexity
If a single guided channel is used to simplify the structure, then the device complexity is reduced, but the field of view is limited
Solution Approach 1:
The optical system is segmented into multiple guided channels (first and second propagation paths) within the waveguide plate. Each channel provides different viewing angles and field of view coverage. By superimposing the optical outputs of these segmented channels, the patent achieves a wider overall field of view without requiring complex external optical systems.
4Area of moving object
If the propagation path length is increased to improve beam expansion, then the beam width is improved, but the spatial intensity distribution becomes uneven
Solution Approach 1:
The patent segments the optical propagation into multiple paths with different lengths. The shorter first path compensates for the intensity loss in the longer second path by delivering higher intensity light to corner regions. This segmentation approach achieves uniform spatial intensity distribution across the entire output beam width without requiring complex intensity correction mechanisms.
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 solution enhances the uniformity of the output light intensity and expands the field of view, ensuring better image quality and reduced waveguide region requirements.
Implementation Method 1
an in-coupling element (1) to form the first guided light (B1), the second guided light (B2), and the first reverse guided light (B-1) and the second reverse guided light (B-2) by diffracting the input light (IN1)
Implementation Method 2
an expander element (2) to form the third guided light (B3) by diffracting the first guided light (B1)
Implementation Method 3
a first retrieval unit (2a) and a second retrieval unit (3a) to form the first retrieval light (B1a) and the second retrieval light (B2a) by diffracting the first reverse guided light (B-1) and the second reverse guided light (B-2)
Implementation Method 4
an out-coupling element (4) to form the first output light (OB4) by diffracting the third guided light (B3) and fourth guided light (B4) to the same direction DIR0'
Data Source
AI summary
This invention relates to an optical expander device with its display device, and a method of light output and image display, including a waveguide plate, the first optical diffractive in-coupling element, the first retrieval unit, the second retrieval unit, the second optical diffractive expander element, the third optical diffractive expander element, and the fourth optical diffractive out-coupling element. The fourth optical diffractive out-coupling element forms part of the first output light (OB4), by diffracting guided light, the third retrieval light (B3a), and the fourth retrieval light (B4a) to the same direction; simultaneously, the fourth optical diffractive out-coupling element diffracts the first direct-through light (B1b) and the second direct-through light (B2b) to the same direction, forming the other part of the first output light (OB4). This device of the present disclosure may greatly improve the uniformity of the intensity distribution of the output light.