Projection Optical System Chromatic Aberration Correction
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Solution Overview
Problem
Conventional optical systems for display apparatuses suffer from chromatic aberration, leading to deteriorated optical performance, and often require additional components to correct this issue, increasing system complexity.
Innovation Solution
A projection optical system comprising a plurality of lenses and a free-formed surface prism, where the light beam is reflected multiple times within the prism, allowing for chromatic aberration correction by optimizing the refractive powers and positions of the lenses and prism surfaces, thereby ensuring a high-quality image without the need for excessive additional components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an optical element with positive power is disposed between the prism and the display element, then the optical system can guide the light beam, but chromatic aberration occurs and optical performance deteriorates
Solution Approach 1:
The patent changes the optical parameters by using a negative lens instead of a positive lens, and specifically sets the focal length to satisfy -5mm < f < -1mm. This parameter change allows the system to guide light while correcting chromatic aberration, resolving the contradiction between ease of operation and optical performance
Solution Approach 2:
The patent converts the harmful effect of chromatic aberration into a benefit by using a negative lens that intentionally introduces opposite chromatic aberration to cancel out the aberration from the prism. The negative lens's chromatic aberration becomes useful for correcting the overall system aberration
2Reliability
If an optical element is added to correct chromatic aberration between the pupil and the prism, then chromatic aberration is corrected, but the number of parts increases
Solution Approach 1:
The patent merges the chromatic aberration correction function into the existing lens unit between the display element and the prism. By selecting appropriate lens combinations (such as a positive and negative lens), the system achieves chromatic aberration correction without adding separate correction elements, thus reducing device complexity while maintaining reliability
Solution Approach 2:
The lens unit serves multiple functions: it guides the light beam from the display element and simultaneously corrects chromatic aberration. This multi-functionality eliminates the need for separate correction elements, reducing the number of parts while achieving the desired optical performance
3Ease of operation
If two lenses with positive powers are disposed between the display element and the prism, then the optical system can function, but chromatic aberration occurs and the observed image deteriorates
Solution Approach 1:
The patent changes the sign of the optical power from positive to negative for at least one lens in the lens unit. Specifically, it uses a negative lens with focal length satisfying -5mm < f < -1mm, which fundamentally changes the optical parameters and enables chromatic aberration correction while maintaining system functionality
Solution Approach 2:
The patent uses a composite lens unit consisting of multiple lenses with different optical properties (positive and negative lenses with specific focal lengths). This composite structure allows the system to achieve both light guidance and chromatic aberration correction, improving image quality while maintaining optical functionality
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 system effectively corrects chromatic aberration, providing a high-quality image while maintaining a sufficient distance between the display element and optical elements, thus enhancing optical performance and reducing system complexity.
Implementation Method 1
a reflection surface configured to reflect the light beam
Implementation Method 2
A plurality of lenses and an optical element are disposed in series between the display element and the light guiding element
Data Source
AI summary
An optical system guides a light beam from a display element, the optical system comprising a plurality of lenses and an optical element. The optical element includes an entrance surface which the light beam from the plurality of lenses enters, a reflection surface configured to reflect the light beam, and an emission surface from which the light beam is emitted toward an exit pupil. The light beam from the display element enters the optical element via the plurality of lenses, is reflected a plurality of times inside the optical element, and heads for the exit pupil. A predetermined condition is satisfied.