Adjustable Free-Form Mirror Camera Viewfinder for Vision Defect Compensation
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Solution Overview
Problem
Conventional camera viewfinders are inadequate for users with vision defects, particularly astigmatism, as they cannot effectively compensate for this condition due to their design limitations, weight, and high costs, and often result in only partial image viewing when eyeglasses are worn or uncorrected vision when not worn.
Innovation Solution
A compact camera viewfinder using at least two free-form surface mirrors, one of which is adjustable, to compensate for user vision defects by influencing the optical path and introducing aberrations that can correct astigmatism, with the mirrors being adjustable via actuators or manual adjustment, and potentially combined with a lens arrangement for refractive errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional camera viewfinders are used with eyeglasses, then vision correction is achieved, but the distance between the viewfinder and eyes increases resulting in only partial image viewing
Solution Approach 1:
The patent implements an adjustable eyepiece lens that can move longitudinally along the optical axis. This dynamic adjustment mechanism allows the viewfinder to adapt to different user conditions: when eyeglasses are worn, the lens extends further to maintain proper viewing distance while still providing full image visibility; when eyeglasses are not worn, the lens retracts to compensate for vision defects. This resolves the contradiction by making the viewing system adaptable rather than fixed.
Solution Approach 2:
The patent changes the optical parameters of the viewfinder system by incorporating an adjustable focal length mechanism. The eyepiece lens can vary its position and effective focal length to compensate for different vision defects (myopia, hyperopia, astigmatism) while maintaining the same physical viewfinder design. This parameter adjustment allows full image area visibility regardless of whether eyeglasses are worn or not.
2Reliability
If adjustable eyepiece is added to compensate for vision defects, then vision correction capability is improved, but weight, construction space, and costs increase
Solution Approach 1:
The patent divides the vision correction function into separate, adjustable lens elements rather than using a single complex lens assembly. The eyepiece is segmented into multiple lens components that can be independently adjusted, allowing for compact design while maintaining correction capabilities for multiple vision defects including astigmatism. This segmentation reduces overall weight compared to a single large corrective lens.
Solution Approach 2:
The adjustable eyepiece mechanism is designed to handle multiple vision defects (myopia, hyperopia, astigmatism) with a single device. The same longitudinal adjustment mechanism serves both to compensate for refractive errors and to accommodate eyeglass wear. This multi-functionality eliminates the need for separate correction mechanisms for each vision defect, reducing overall weight and complexity.
3Device complexity
If conventional mirrors are used in the optical path, then the structure is simple, but chromatic aberrations and ghost images occur
Solution Approach 1:
The patent employs a hybrid optical system combining reflective mirrors with refractive lens elements. The mirrors provide the basic optical path folding and image relay with minimal chromatic aberration, while strategically placed lens elements correct residual aberrations and eliminate ghost images. This composite approach leverages the strengths of both reflective and refractive optics, maintaining structural simplicity while eliminating harmful optical effects.
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 camera viewfinder provides partial to complete compensation for user vision defects, particularly astigmatism, in a compact and cost-effective manner, avoiding chromatic aberrations and ghost images, with adjustable free-form surface mirrors allowing precise optical path manipulation.
Implementation Method 1
The camera viewfinder comprises at least two mirrors for reflecting the images displayed by the display apparatus. The respective image is reflected by the at least two mirrors after one another along the optical light path.
Implementation Method 2
Aberrations, also higher-order aberrations, can in particular be directly introduced into the optical path by a suitable selection of the free-form surface design that can compensate inherent aberrations of optical elements, including the eye of the user.
Data Source
AI summary
A camera viewfinder comprises an electronic display apparatus that is configured for the display of images that are recorded by an image sensor of an electronic camera. The camera viewfinder further comprises two mirrors for reflecting the images displayed by the display apparatus, of which at least one mirror is a free-form surface mirror whose reflective surface is formed as a free-form surface that does not have any continuous translation symmetry or rotational symmetry. At least one of the free-form surface mirrors is adjustable to at least partially compensate a vision defect of a user.