Folded Optical Display Layout With Diffractive Aberration Correction
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Solution Overview
Problem
Current display devices with folded optical paths suffer from low optical efficiency and optical aberrations such as spherical aberration, coma, astigmatism, and chromatic dispersion, which are exacerbated by increasing lens surfaces to meet higher resolution demands, leading to increased costs and challenging optical design.
Innovation Solution
Incorporation of a polarization light splitting element, transflective element, diffraction optical element, quarter wave plate, and lenses, particularly utilizing a cholesterol liquid crystal lens with inverse chromatic dispersion characteristics to compensate for lens dispersion and reflect and reuse lost light beams, thereby enhancing optical efficiency and correcting chromatic aberrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a folded optical path structure is adopted to reduce TTL, then the total track length is reduced by 50%-60%, but optical efficiency drops to 25% of the original due to light polarization loss at half mirrors
Solution Approach 1:
The patent changes the optical path configuration from a traditional folded path using half mirrors to a virtual image formation path using a reflection-type liquid crystal display panel. This parameter change in the optical system architecture eliminates the need for multiple half mirrors, thereby reducing polarization-related light loss while maintaining the compact TTL advantage
Solution Approach 2:
The patent uses a diffraction optical element to generate a virtual image of the display panel, effectively creating a copied optical path that appears longer but physically occupies less space. This allows the system to achieve extended optical path length for imaging quality while maintaining compact physical dimensions, and the virtual image approach avoids additional light loss from physical mirror reflections
2Reliability
If the number of lens surfaces is increased to minimize optical aberrations, then spherical aberration, coma, and astigmatism are reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs a diffractive optical element that combines refractive and diffractive optical properties in a single component. This composite approach allows the element to correct multiple types of optical aberrations (spherical, coma, astigmatism) simultaneously without requiring multiple separate lenses, thereby maintaining high optical quality while reducing system complexity
Solution Approach 2:
The diffractive optical element serves multiple functions: it focuses light, corrects optical aberrations, and compensates for chromatic dispersion. By integrating these multiple functions into a single element rather than requiring separate components for each function, the patent reduces the overall number of optical elements needed while achieving superior optical performance
3Measurement precision
If resolution requirements are increased for smaller pixels, then imaging quality improves, but the number of lenses must increase to meet the requirements, making optical design more challenging and increasing cost
Solution Approach 1:
The diffractive optical element with composite refractive-diffractive structure provides enhanced optical performance that enables high-resolution imaging with fewer components. The diffractive micro-structures within the element can be precisely controlled at the micro-scale to achieve the required resolution while maintaining a simplified overall optical design
Solution Approach 2:
The patent changes the approach to resolution enhancement by using a reflection-type liquid crystal display panel with high pixel density in combination with a virtual image formation system. This parameter change in the display panel technology and optical configuration allows achieving high resolution without proportionally increasing the number of optical lenses, thereby reducing design complexity and cost
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 display device achieves improved optical efficiency of 50% and reduced chromatic aberrations, providing better imaging quality while maintaining a compact form factor.
Implementation Method 1
a diffraction optical element (120)... reflects and reuses the image beam whose optical efficiency would originally be lost through the configuration of the diffraction optical element
Implementation Method 2
when the diffraction optical element is a cholesterol liquid crystal lens, the display device further utilizes the inverse chromatic dispersion characteristics of the diffraction optical element as a compensator for lens dispersion in the imaging system
Implementation Method 3
when the diffraction optical element is a cholesterol liquid crystal lens
Implementation Method 4
the technical structure of folded optical paths adopts the characteristics of a light polarization state and achieves the effect of a folded optical path through the disposition of a half mirror
Implementation Method 5
a quarter wave plate, and at least one lens... The quarter wave plate is located between the transflective element and the polarization light splitting element
Data Source
AI summary
A display device, including a display panel, a polarization light splitting element, a transflective element, a diffraction optical element, a quarter wave plate, and at least one lens. The display panel is used to provide an image beam. The polarization light splitting element, the transflective element, the diffraction optical element, the quarter wave plate, and the at least one lens are located on a transmission path of the image beam. The transflective element is located between the polarization light splitting element and the display panel. The diffractive optical element is located between the transflective element and the display panel. The quarter wave plate is located between the transflective element and the polarization light splitting element. The at least one lens is located between the diffractive optical element and the quarter wave plate.