AR Waveguide Input Coupling With Telecentric Light Control
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Solution Overview
Problem
Conventional waveguides for augmented reality displays suffer from limited viewing angles, difficulty in making the waveguide thin, and degradation of image quality due to non-uniform light propagation and diffusion.
Innovation Solution
A display device incorporating a telecentric assembly to ensure uniform light incidence into the waveguide, coupled with an input coupler and output couplers to maintain consistent angles and intensity, and a direction-selection diffuser or polarization volume grating to enhance light uniformity and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If free-form surface reflection or multi-mirror reflection is used in waveguide, then structure may be simple and light transmission efficiency may be high, but viewing angle may be limited and it may be difficult to make the waveguide relatively thin
Solution Approach 1:
The patent replaces mechanical reflection systems (free-form surfaces and multi-mirrors) with a diffractive optical element-based waveguide. This substitution enables light to be coupled into the waveguide through diffraction at the input surface, allowing for better control of light propagation angles and enabling the waveguide to achieve both structural simplicity and wide viewing angles simultaneously.
Solution Approach 2:
The patent changes the fundamental parameter of light-matter interaction from reflection to diffraction. By using a diffractive optical element with specific grating patterns, the waveguide can control light propagation through diffraction angles, enabling both thin waveguide structure and wide viewing angle without the limitations of reflective systems.
2Ease of manufacture
If free-form surface reflection or multi-mirror reflection is used in waveguide, then structure may be simple and light transmission efficiency may be high, but it may be difficult to make the waveguide relatively thin
Solution Approach 1:
The patent replaces mechanical reflection systems with a diffractive optical element-based waveguide. This substitution enables light to be coupled into the waveguide through diffraction at the input surface, allowing for better control of light propagation angles and enabling the waveguide to achieve both structural simplicity and wide viewing angles simultaneously.
Solution Approach 2:
The patent changes the fundamental parameter of light-matter interaction from reflection to diffraction. By using a diffractive optical element with specific grating patterns, the waveguide can control light propagation through diffraction angles, enabling both thin waveguide structure and wide viewing angle without the limitations of reflective systems.
3Loss of energy
If conventional waveguide light input methods are used, then light transmission efficiency may be high, but due to the low uniformity of light propagating through the waveguide, image quality may be degraded
Solution Approach 1:
The patent applies local quality by using a diffractive optical element with spatially varying grating patterns across the input surface. Different regions of the input surface have different diffraction characteristics, which locally control the angle and distribution of light entering the waveguide. This ensures uniform light propagation throughout the waveguide while maintaining high transmission efficiency, thereby improving image quality.
Solution Approach 2:
The patent replaces mechanical reflection systems with a diffractive optical element-based waveguide. This substitution enables light to be coupled into the waveguide through diffraction at the input surface, allowing for better control of light propagation angles and enabling the waveguide to achieve both structural simplicity and wide viewing angles simultaneously.
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 ensures consistent image quality and brightness across the viewing area by maintaining uniform light propagation and intensity, enabling high-quality augmented reality displays with improved viewing angles and reduced thickness.
Implementation Method 1
a telecentric assembly provided between the display element and the waveguide, the telecentric assembly being configured to cause incident angles of light beams incident on the input coupler to be same as each other
Implementation Method 2
an input coupler provided on the waveguide and configured to input the light into the waveguide
Implementation Method 3
an output coupler configured to output light propagating in the waveguide to an outside of the waveguide
Implementation Method 4
a waveguide including a first surface to which the light is incident and a second surface opposite the first surface
Data Source
AI summary
A display device includes a display element configured to output light to display an image, a waveguide including a first surface to which the light is incident and a second surface opposite the first surface, an input coupler provided in the waveguide to input the light into the waveguide, a telecentric assembly configured to cause incident angles of light beams incident to the input coupler to be the same as each other, and an output coupler configured to output light propagating in the waveguide to outside of the waveguide.