Optical Engine Module Diffusion Elements for Near-Eye Display Color Shift
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Solution Overview
Problem
Near-eye display technologies face challenges in maintaining image quality and light collection efficiency due to color shifts and uneven off-axis color caused by the spectroscopic characteristics of polarizing beam splitting elements, especially when the field of view exceeds certain angles, affecting the performance of optical engine modules in augmented and virtual reality applications.
Innovation Solution
The optical engine module incorporates a light source unit, a first diffusion element, a polarizing beam splitting element, and a second diffusion element with optical surfaces that reflect and diffuse light beams, forming an illumination beam with an optical image matching angle, which is then converted into an image beam by a light valve, and projected using a projection lens, thereby expanding the unit optical divergence angle of sub-beams to satisfy the optical path requirements and reduce diffusion angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarizing beam splitting element is used in the optical engine module, then the light beam can be polarized and directed to the light valve, but color shift and uneven off-axis color occur due to spectroscopic characteristics when the field of view exceeds certain angles
Solution Approach 1:
A diffusion element is introduced as an intermediary component between the light source unit and the polarizing beam splitting element. This diffusion element scatters the light beam to reduce the incident angle, thereby preventing color shift caused by the polarizing beam splitting element's spectroscopic characteristics while maintaining effective light polarization and direction control
2Adaptability or versatility
If the field of view is increased above certain angles to expand the viewing area, then the near-eye display can cover a wider field of view, but light collection efficiency decreases due to large incident angles on the polarizing beam splitting element
Solution Approach 1:
The diffusion element serves as a mediator that transforms the light beam's angular distribution. It allows the optical system to accept light from a wider field of view while converting these wide-angle rays into narrower incident angles that the polarizing beam splitting element can handle efficiently, thus maintaining light collection efficiency across an expanded field of view
3Manufacturing precision
If the incident angle of light beam on the polarizing beam splitting element is reduced to prevent color shift, then color uniformity is improved, but the optical path length and device complexity increase due to additional diffusion elements
Solution Approach 1:
The diffusion element is strategically positioned only at the specific location where light enters the polarizing beam splitting element, affecting only the local angular distribution of light at that interface. This localized intervention corrects color uniformity issues without requiring modification of the entire optical path, thereby minimizing added 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 ensures good image quality and resolution by adjusting the uniformity and optical shape of sub-beams, matching the optical image matching angle with the viewing angle, reducing product costs while maintaining image quality and satisfying the optical path requirements in projection lenses.
Implementation Method 1
a first diffusion element, configured to diffuse the light beam
Implementation Method 2
The at least one optical surface is configured to reflect and diffuse the light beam
Implementation Method 3
The at least one optical surface is configured to reflect and diffuse the light beam
Implementation Method 4
a polarizing beam splitting element, configured to polarize the light beam
Data Source
Figure 1A~1B
Figure 2~3
AI summary
An optical engine module and a projection device are provided. The optical engine module includes a light source unit, a first diffusion element, a polarizing beam splitting element, a second diffusion element, and a light valve. The light source unit emits a light beam. The first diffusion element is disposed on a transmission path of the light beam. The polarizing beam splitting element is disposed on the transmission path of the light beam. The first diffusion element is disposed between the polarizing beam splitting element and the light source unit. The second diffusion element has at least one optical surface to reflect and diffuse the light beam. The light beam forms an illumination beam after passing through the second diffusion element, and the illumination beam has an optical image matching angle. The light valve is disposed on a transmission path of the illumination beam. The light valve converts the illumination beam to an image beam.