Virtual Image Display Device with Polarization Separation Lens
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing virtual image display devices face challenges in increasing the angle of view while maintaining a compact size, as thicker beam splitters are required to achieve wider fields of view, leading to larger optical systems.
Innovation Solution
The virtual image display device incorporates a light shielding member, a polarizing plate, an image selection conversion member with a wavelength plate, and a polarization separation liquid crystal lens to regulate and change the polarization direction of image light, allowing for a larger angle of view without significantly increasing the device's size by using a polarization separation liquid crystal lens with adjustable refractive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the beam splitter is increased in thickness to increase the angle of view, then the angle of view is improved, but the optical system size increases
Solution Approach 1:
The patent changes the optical parameters by introducing a polarization separation lens element with specific refractive power that acts selectively on s-polarized light. This allows the beam splitter to be made thinner while still achieving the desired angle of view, as the polarization separation mechanism compensates for the reduced thickness. The wavelength plate also changes the polarization state of light to enable this selective refraction approach.
Solution Approach 2:
The patent replaces the traditional mechanical approach of increasing beam splitter thickness with an optical mechanism involving polarization separation. Instead of relying on geometric thickness to control the angle of view, the system uses the interaction between polarized light and the polarization separation lens element to achieve the same effect with a thinner component.
2Adaptability or versatility
If a polarization separation lens element with selective refractive power is used, then the angle of view is increased without increasing size, but the optical system complexity increases
Solution Approach 1:
The polarization separation lens element serves multiple functions: it acts as a refractive element to increase the angle of view, simultaneously functions as a polarization-dependent optical element to control light paths, and works in conjunction with the wavelength plate to manage polarization states. This multi-functionality reduces the need for separate components, thereby limiting the increase in overall system complexity.
Solution Approach 2:
The wavelength plate acts as an intermediary element that modifies the polarization state of incident light before it reaches the polarization separation lens element. This intermediary function enables the lens element to selectively refract only s-polarized light, achieving the desired angle of view expansion without requiring additional complex optical components.
3Adaptability or versatility
If external light is allowed to pass through for see-through display, then external image recognition is improved, but image display quality deteriorates due to light interference
Solution Approach 1:
The patent applies different optical properties to different polarization states of light. External light (unpolarized or differently polarized) passes through the system with minimal interference, while the displayed image light (specifically s-polarized) is selectively refracted by the polarization separation lens element. This local differentiation of optical treatment maintains both see-through capability and image display quality.
Solution Approach 2:
The wavelength plate changes the polarization state of the displayed image light, effectively 'coloring' it with a specific polarization property. This polarization 'color' distinguishes the image light from external light, allowing the optical system to treat them differently - the image light is refracted to form a clear display, while external light passes through for see-through functionality.
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 enables an increased angle of view while maintaining a compact form factor, allowing for the formation of virtual images with reduced chipping and enabling display on large screens with a small-sized optical system, while also allowing for see-through recognition of external images.
Implementation Method 1
a polarizing plate being arranged on a face side of the image display device and being configured to limit transmitted light to a predetermined polarization direction
Implementation Method 2
an image selection conversion member being arranged on a face side of the polarizing plate and including a wavelength plate for selectively changing a polarization direction of image light
Implementation Method 3
a polarization separation lens element being arranged on a face side of the image selection conversion member and having refractive power selectively acting on polarization of the image light
Data Source
AI summary
A virtual image display device includes an image display device including a pixel display region for displaying an image and a light transmitting region for causing an external to be visually recognizable, a light shielding member being arranged on an external side of the image display device and being configured to suppress incidence of external light on the pixel display region, a polarizing plate being arranged on a face side of the image display device and being configured to limit transmitted light to a predetermined polarization direction, an image selection conversion member being arranged on a face side of the polarizing plate and including a wavelength plate for selectively changing a polarization direction of image light according to the pixel display region, and a polarization separation lens element being arranged on a face side of the image selection conversion member.