Multi-Stage Light Homogenizing Assembly for Speckle Reduction
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Solution Overview
Problem
Existing projection devices face challenges in achieving a simple structure with uniform color and effective speckle elimination, often relying on diffusion sheets and dynamic elements that are not ideal in terms of volume and cost, and conventional optical elements like compound eye lenses fail to adequately homogenize light, resulting in color spots and high-time and spatial coherence.
Innovation Solution
A light homogenizing assembly comprising a first light homogenizing member, a light-spot shaping lens group, and a second light homogenizing member, with optional additional components like diffusion sheets and collimating lenses, to sequentially homogenize and shape light, reducing speckle phenomena and improving uniformity through multiple stages of homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a diffusion sheet and dynamic elements are used for light homogenization, then light uniformity is improved, but device volume and cost increase
Solution Approach 1:
The light homogenization function is segmented into multiple stages: the first light homogenizing member performs initial homogenization, the light-spot shaping lens group shapes and redistributes light, and the second light homogenizing member performs final homogenization. This multi-stage segmentation achieves superior light uniformity while maintaining a compact overall structure.
Solution Approach 2:
The patent employs a nested arrangement where the light-spot shaping lens group is positioned between two light homogenizing members, creating a compact nested structure. The focal points of lenses are coincident with the positions of homogenizing members, enabling space-efficient nesting that reduces device volume while maintaining effective light homogenization.
2Device complexity
If conventional compound eye lenses are used for light homogenization, then device structure is simplified, but light homogenization effect deteriorates
Solution Approach 1:
Instead of using a single conventional compound eye lens, the patent segments the light homogenization function into multiple dedicated components: a first light homogenizing member, a light-spot shaping lens group, and a second light homogenizing member. Each component performs a specific function in sequence, achieving superior light homogenization while maintaining reasonable structural complexity.
Solution Approach 2:
The light-spot shaping lens group acts as an intermediary between the two light homogenizing members. It receives homogenized light from the first member, shapes and redistributes the light spots, and directs the shaped light to the second homogenizing member for final homogenization. This intermediary component enables effective light homogenization that conventional single-stage systems cannot achieve.
3Ease of manufacture
If conventional optical elements are used, then device cost is reduced, but speckle elimination effect deteriorates
Solution Approach 1:
The patent segments the speckle elimination process into multiple stages using conventional optical elements. The first light homogenizing member performs initial speckle reduction, the light-spot shaping lens group redistributes light to further reduce speckle, and the second light homogenizing member performs final speckle elimination. This multi-stage approach using conventional elements achieves effective speckle elimination while controlling device cost.
Solution Approach 2:
The light-spot shaping lens group introduces spatial redistribution of light in multiple dimensions. By shaping and redistributing light spots across different spatial positions and angles, it adds dimensional complexity to the light path, effectively reducing speckle phenomena while using conventional optical elements that maintain cost-effectiveness.
Data Source
AI summary
Embodiments of the present disclosure propose a light homogenizing assembly, a projection optical unit and a projection device. The light homogenizing assembly includes a first light homogenizing member, a light-spot shaping lens group and a second light homogenizing member, which are sequentially arranged along an optical path. The first light homogenizing member is configured to homogenize light emitted by a light source. The light-spot shaping lens group includes at least one light-spot shaping lens. The light-spot shaping lens is configured to shape light spots of light emitted by the first light homogenizing member and to emit the light spots to a light incident side of the second light homogenizing member. The second light homogenizing member is configured to homogenize light emitted by the light-spot shaping lens group.