Head-Mounted Display Optical Path Miniaturization
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Solution Overview
Problem
Existing head-mounted display apparatuses are bulky and heavy due to the use of light-guiding plates, leading to discomfort for users as they can apply excessive weight on the nose, causing an unpleasant feeling.
Innovation Solution
A head-mounted display apparatus with an image generating module, first and second deflecting elements, and diffraction elements, including a color synthesizing element with dichroic films, which guides imaging light through a series of optical axes to reduce the size and weight, and incorporates a reflection-type volume hologram for efficient light management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-guiding plate is used to guide imaging light to the observer's eye, then the head-mounted display apparatus can achieve light guidance function, but the apparatus becomes large and heavy
Solution Approach 1:
The patent removes the light-guiding plate from the optical system and replaces it with a combination of reflection surfaces and diffraction elements. This extraction of the bulky light-guiding plate directly reduces the apparatus weight and size while maintaining the light guidance function through the alternative optical path formed by the deflecting elements and diffraction grating.
Solution Approach 2:
The patent substitutes the mechanical light-guiding plate structure with an optical system consisting of reflection surfaces and diffraction elements. This replacement uses optical phenomena (reflection and diffraction) instead of mechanical light guiding, achieving the same function with significantly reduced weight and complexity.
2Reliability
If the light-guiding plate and optical members are designed with certain size and weight parameters, then the light guidance function is achieved, but excessive weight is applied to the user's nose causing unpleasant feeling
Solution Approach 1:
By removing the light-guiding plate and replacing it with lighter reflection surfaces and diffraction elements, the overall apparatus weight is reduced. This directly decreases the pressure applied to the user's nose and eliminates the harmful effect of discomfort while preserving the essential light guidance function.
Solution Approach 2:
The patent changes the optical path parameters by using multiple reflection surfaces at specific angles (45 degrees) and positioning diffraction elements at optimized locations. This reconfiguration allows the optical system to achieve the same light guidance function with a more compact and lighter arrangement, reducing nose pressure and improving user comfort.
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 miniaturizes the display apparatus, reduces pressure on the nose, and enhances user comfort by optimizing the optical path and eliminating the need for a light-guiding plate, allowing for a more compact and lightweight design.
Implementation Method 1
the first deflecting portion is configured to deflect, along a second optical axis intersecting the first optical axis, the imaging light emitted from the image generating module
Implementation Method 2
the second deflecting portion is configured to deflect, along a third optical axis intersecting the second optical axis, the imaging light deflected by the first deflecting portion
Implementation Method 3
a first diffraction element configured to diffract the imaging light deflected by the second deflecting portion
Implementation Method 4
a second diffraction element configured to diffract the imaging light diffracted by the first diffraction element to form an exit pupil
Implementation Method 5
the color synthesizing element includes a first synthesis film and a second synthesis film, which are intersect each other
Data Source
AI summary
A head-mounted display apparatus according to the present disclosure includes an image generating module, a first deflecting element including a first deflecting portion configured to deflect, along a second optical axis intersecting the first optical axis, imaging light from the image generating module, and a second deflecting portion configured to deflect the imaging light along a third optical axis, a first diffraction element configured to diffract the imaging light from the second deflecting portion, and a second diffraction element configured to diffract the imaging light from the first diffraction element. A distance along the first optical axis between the image generating module and the first deflecting portion is longer than a distance along the third optical axis between the first diffraction element and the second deflecting portion.