Head-Mount Vision Testing Device Using Bent Optical Axis
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Solution Overview
Problem
The existing head-mount type vision testing devices are large in size due to the requirement of a large display device to present visual targets over a wide angle, leading to increased size and instability when mounted on a user's head.
Innovation Solution
A vision testing device with a bent display optical system that uses a first lens with high positive refractive power, a mirror, and a second lens group to converge light from the retina onto a small display device, optimizing the optical axis configuration to reduce the device's size and improve weight balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large-sized display device is used to present visual targets over a wide angle, then the visual field coverage is improved, but the device size increases
Solution Approach 1:
The patent bends the optical axis of the display optical system to arrange components in a three-dimensional configuration rather than a linear arrangement. This allows the display device to present visual targets over a wide angle while maintaining a compact form factor by utilizing spatial dimensions efficiently.
Solution Approach 2:
The patent uses a first lens with high positive refractive power to change the optical parameters of the system. This enables the convergence of light from the retina onto a small display device, achieving wide-angle visual field coverage without requiring a large display area.
2Device complexity
If the display device is arranged to face the eyeballs directly, then the optical path is simplified, but the device size increases
Solution Approach 1:
The patent bends the optical axis to arrange the display device and optical components in a compact three-dimensional configuration. This maintains relatively simple light paths while achieving compact device size by utilizing spatial arrangement rather than linear extension.
3Device complexity
If a single lens is used to form images on the retina, then the optical system is simplified, but the device size increases
Solution Approach 1:
The patent employs a first lens with high positive refractive power to change the optical parameters, enabling effective light convergence onto a small display device. This achieves compact device size while maintaining a relatively simple single-lens optical system.
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 results in a smaller, more stable head-mount type vision testing device that effectively presents visual targets over a wide angle without increasing the overall size, maintaining balance and preventing the device from falling off during head movement.
Implementation Method 1
a first lens with high positive refractive power
Implementation Method 2
converge light from the retina onto a small display device
Implementation Method 3
a mirror, and a second lens group to converge light
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
There is provided a small-sized head-mount type vision testing device, which is a head-mount type vision testing device mounted on a testee's head, including: a display device that presents a visual target to an eyeball of the testee; a display optical system that guides a light of the visual target presented on the display device, to a retina of the eyeball; an imaging device that images the eyeball; and an observation optical system that guides an image of the eyeball to the imaging device, the display optical system further comprising a mirror that reflects a light of a specific wavelength and transmits the other light at a point closer to the eyeball side than the display device, wherein an optical axis from a pupil of the eyeball to the mirror in the display optical system and an optical axis from the pupil to the mirror in the observation optical system, coincide with each other, and the optical axis from the pupil of the eyeball to the mirror in the display optical system and an optical axis from the mirror to the display device in the display optical system, are bent through the mirror.