Head-Mounted Display Pancake Optics for Reduced Polarization Loss
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Solution Overview
Problem
Head-mounted display devices suffer from low light efficiency due to the use of polarizers, which absorb a significant portion of the emitted light.
Innovation Solution
The device incorporates a reflective polarizer in the optical system and a display panel, along with a pancake lens, and includes an open portion in the absorptive polarizer to allow light recycling without absorption, utilizing retarders to change polarized light types and a beam splitter to enhance light transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If an absorptive polarizer is used in the head-mounted display device, then polarization control is achieved, but light efficiency deteriorates due to absorption of a significant portion of emitted light
Solution Approach 1:
The patent removes the absorptive polarizer from the optical path entirely, extracting the harmful light-absorbing component while retaining polarization control functionality through reflective polarizers and retarders that do not absorb light
Solution Approach 2:
The patent converts the harmful light absorption mechanism into a beneficial reflective mechanism, where polarizers reflect rather than absorb light, thereby maintaining polarization control while eliminating energy loss through absorption
2Reliability
If polarizers are used to control light in the head-mounted display device, then polarization management is improved, but power consumption increases due to reduced light efficiency
Solution Approach 1:
The patent transforms the energy-wasting absorptive polarization mechanism into an energy-efficient reflective polarization mechanism, maintaining reliable polarization control while converting what was previously a harmful energy loss into a beneficial non-absorptive light management approach
Solution Approach 2:
The patent changes the fundamental operating parameter of the polarizer from absorptive to reflective mode, altering how polarization is achieved from a process that consumes light energy to one that preserves and redirects it
3Illumination intensity
If a reflective polarizer is used instead of an absorptive polarizer, then light efficiency is improved by reducing absorption loss, but device complexity increases due to additional optical components
Solution Approach 1:
The patent merges the reflective polarizer with the existing display panel structure and integrates it with retarders and curved lenses as a unified optical system, reducing overall complexity despite the change from absorptive to reflective polarization
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 significantly improves light efficiency, allowing for brighter images with reduced power consumption and extended battery life in head-mounted displays.
Implementation Method 1
the retarder may have a first delay axis, and delay light in a direction of the first delay axis by λ/4 to change linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light
Implementation Method 2
the reflective polarizer of the display panel may have a first reflection axis, and reflects polarized light of the first reflection axis, and transmit polarized light perpendicular to the first reflection axis
Implementation Method 3
the absorptive polarizer of the display panel may have a light absorption axis, and absorbs polarized light of the light absorption axis, and transmit polarized light perpendicular to the light absorption axis
Implementation Method 4
a beam splitter positioned on an outer surface
Data Source
AI summary
A head-mounted display device includes a display panel and an optical system positioned on a front surface of the display panel, wherein the display panel sequentially includes a light emitting element unit, a retarder positioned on a front surface of the light emitting element unit, a reflective polarizer, and an absorptive polarizer, wherein the optical system includes a first curved lens configured to include a first retarder positioned on an inner surface and a beam splitter positioned on an outer surface and a second curved lens configured to include a second retarder positioned on an inner surface and a reflective polarizer positioned on an outer surface, wherein the first curved lens is positioned on the display panel, and the second curved lens is positioned on the first curved lens, and wherein the absorptive polarizer of the display panel includes an open portion from which the absorptive polarizer is removed.