Holographic Projector Focus Depth Adjustment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing projectors using laser light sources face challenges in balancing focusing freedom with speckle noise reduction, as previous methods either prioritize noise reduction or focusing freedom but not both effectively.
Innovation Solution
A projector design incorporating a holographic recording medium, a condensing optical system, a light modulation element, and a focus depth adjustment unit that adjusts the projection numerical aperture by inserting or removing a magnifying or reduction optical system, or using a scanning optical system, to achieve both reduced speckle noise and enhanced focusing freedom without vignetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If laser light is used as the light source for a projector, then focusing freedom is greatly enhanced with very large focusing depth, but speckle noise occurs which exerts a negative influence upon the projected image
Solution Approach 1:
The patent makes the projection numerical aperture variable by dynamically adjusting the diameter of the laser light ray bundle incident on the holographic recording medium. A magnifying optical system can be inserted or removed from the optical path to change the ray bundle diameter, thereby adjusting the projection numerical aperture. This dynamic adjustment allows the system to switch between deep focus mode (small numerical aperture) and speckle noise reduction mode (large numerical aperture), resolving the contradiction between focusing freedom and speckle noise.
2Object-generated harmful factors
If the diameter of the laser light ray bundle is increased to enlarge the projection numerical aperture, then speckle noise is reduced, but freedom in focusing is compromised
Solution Approach 1:
The system employs a variable projection numerical aperture that can be dynamically adjusted. When speckle noise reduction is prioritized, the magnifying optical system is inserted to increase the ray bundle diameter and enlarge the projection numerical aperture. When focusing freedom is prioritized, the magnifying system is removed to maintain a small projection numerical aperture and deep focus. This dynamic configurability resolves the contradiction by allowing optimal settings for different usage scenarios.
3Object-generated harmful factors
If a magnifying optical system is inserted to increase the ray bundle diameter and reduce speckle noise, then device complexity increases
Solution Approach 1:
The patent introduces a magnifying optical system that can be inserted into or removed from the optical path between the condensing optical system and the holographic recording medium. This dynamic insertion/removal mechanism allows the system to adjust the ray bundle diameter and projection numerical aperture as needed. While this adds some complexity, it enables the system to achieve both deep focus capability and speckle noise reduction by configuring the optical path according to different usage requirements.
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
The solution allows for seamless switching between low speckle noise and deep focus modes, ensuring high-quality projection with adjustable focus depth and reduced noise, accommodating various usage environments and screen types.
Implementation Method 1
a holographic recording medium that, when laser light for reproduction is incident thereupon, emits a reproduced holographic optical image on the basis of a holographic image
Implementation Method 2
a condensing optical system that collimates the laser light
Implementation Method 3
a light modulation element that modulates the reproduced holographic image and emits the result to a projection optical system as an optical image for projection
Data Source
AI summary
A projector includes: a laser light source that emits laser light; a condensing optical system that collimates the laser light; a holographic recording medium that, when laser light for reproduction is incident thereupon, emits a reproduced holographic optical image on the basis of a holographic image; a light modulation element that modulates the reproduced holographic optical image and emits the result to a projection optical system as an optical image for projection; a projection optical system that projects the optical image for projection; and a focal depth adjustment unit that adjusts a focus depth of the ray bundle projected by the projection optical system.