Diffractive Display Device Wavelength Compensation via Conjugate Optics
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Solution Overview
Problem
Existing display devices using diffractive elements for wavelength compensation are insufficient in achieving effective wavelength compensation, leading to degradation of image resolution due to peripheral wavelengths.
Innovation Solution
A display device configuration with specific optical sections and diffractive elements is implemented, where the first intermediate image is formed between the first and third optical sections, and the second intermediate image between the third and fourth optical sections, ensuring a conjugate relation between the diffractive elements to effectively compensate for peripheral wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If two diffractive elements are used for wavelength compensation, then resolution degradation from peripheral wavelengths is prevented, but the conjugate relation between diffractive elements is not achieved, resulting in insufficient wavelength compensation
Solution Approach 1:
The patent introduces a light guide plate as an intermediary component between the first and second diffractive elements. The light guide plate includes a light incident surface and a light extraction surface positioned at different locations, serving as a mediator to establish the conjugate relation between the diffractive elements. The intermediate image is formed at the light extraction surface, enabling proper wavelength compensation while maintaining image quality.
2Device complexity
If the intermediate image is formed at different positions, then the optical path is simplified, but the diffractive elements do not achieve conjugate relation, causing insufficient wavelength compensation
Solution Approach 1:
The light guide plate serves as a mediator that reconciles the contradiction between optical path simplicity and wavelength compensation effectiveness. By positioning the intermediate image at the light extraction surface rather than requiring complex optical components, the system achieves both simplicity and effective wavelength compensation through the conjugate relation established by the light guide plate.
3Volume of moving object
If the first intermediate image is formed between the second optical section and the third optical section, then the optical system is more compact, but wavelength compensation is less sufficient compared to forming it between the first and second optical sections
Solution Approach 1:
The light guide plate acts as an intermediary that enables compact optical system design while maintaining effective wavelength compensation. The intermediate image is formed at the light extraction surface of the light guide plate, which is positioned between the first and second diffractive elements, achieving both compactness and sufficient wavelength compensation.
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
This configuration ensures that the image light is properly compensated, preventing resolution deterioration and maintaining image quality by aligning the diffractive elements for optimal wavelength handling.
Implementation Method 1
a display device for deflecting image light having been emitted from an image light generation device toward the eyes of an observer using a diffractive element
Implementation Method 2
a first optical section having positive power, a second optical section provided with a first diffractive element and having positive power, a third optical section having positive power, and a fourth optical section provided with a second diffractive element and having positive power
Data Source
AI summary
In an optical system, a first optical section having positive power, a second optical section provided with a first diffractive element and having positive power, a third optical section having positive power, and a fourth optical section provided with a second diffractive element and having positive power are disposed along a light path of image light emitted from an image light generation device. A first intermediate image of the image light is formed between the first optical section and the third optical section, a pupil is formed in the vicinity of the third optical section, a second intermediate image of the image light is formed between the third optical section and the fourth optical section, and the fourth optical section collimates the image light to form an exit pupil. The first diffractive element and the second diffractive element are in a conjugate relation or a roughly conjugate relation.