Projection Display Polarization Element Displacement
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Solution Overview
Problem
The polarization converting element in projection display apparatuses deteriorates due to heat from collected light flux, leading to reliability issues, even when cooled by air, as the adhesive used in the PBS prism and half-wave plates degrades through oxidation and photochemical reactions, affecting both polycarbonate and crystal materials.
Innovation Solution
A projection display apparatus is designed with a light source, a first and second lens array to split and refract light, a polarization converting element that splits and conforms polarized light, and a drive mechanism to displace the polarization converting element perpendicular to the polarization split direction, reducing constant illumination on specific areas and thus minimizing heat-induced deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the polarization converting element is cooled by air, then the element can operate continuously, but the adhesive degrades through oxidation and photochemical reactions leading to deterioration
Solution Approach 1:
The patent applies the dynamics principle by making the polarization converting element movable rather than fixed. The element can be displaced in one direction perpendicular to the polarization split direction, allowing it to move between positions that change the distribution of incident light. This dynamic positioning prevents constant illumination of specific areas, thereby reducing heat accumulation and adhesive degradation over time.
Solution Approach 2:
The patent implements periodic action through the displacement mechanism that periodically changes the position of the polarization converting element. By moving the element between different positions, the system creates periodic variations in light distribution, preventing continuous heating at any single location and thereby extending the operational life of the adhesive.
2Ease of manufacture
If half-wave plates are made of polycarbonate, then the element is easy to manufacture, but the plates are easily deteriorated due to heat sensitivity
Solution Approach 1:
The patent uses the dynamics principle to address the heat sensitivity of polycarbonate half-wave plates by making the entire polarization converting element movable. This allows the element to be repositioned to change light distribution patterns, preventing localized heat buildup that would otherwise accelerate the deterioration of heat-sensitive polycarbonate materials.
3Reliability
If the polarization converting element is displaced, then constant illumination on specific areas is reduced, but the device complexity increases due to the drive mechanism
Solution Approach 1:
The patent applies the dynamics principle by introducing a drive mechanism that displaces the polarization converting element in one direction perpendicular to the polarization split direction. This dynamic positioning changes the light distribution pattern, preventing constant illumination of specific areas and thereby reducing heat-induced deterioration of the element.
Solution Approach 2:
The patent implements segmentation by dividing the polarization converting element into functional components (PBS prism and half-wave plates) that can be independently positioned and controlled. This segmentation allows for targeted displacement of specific portions of the element to optimize light distribution while managing the overall complexity through modular design.
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 reduces the deterioration of the polarization converting element by dispersing high luminance areas and minimizing constant light exposure, thereby enhancing the reliability and longevity of the apparatus.
Implementation Method 1
a first lens array in which a plurality of lens cells is two-dimensionally arranged and split light flux emitted from the light source; a second lens array in which a plurality of lens cells corresponding to the plurality of lens cells in the first lens array is two-dimensionally arranged, and on which light emitted from the first lens array is incident
Implementation Method 2
a polarization converting element that splits indefinite polarized light emitted from the second lens array into first polarized light and second polarized light
Implementation Method 3
provided with half-wave plates that convert the first polarized light into the second polarized light, or the second polarized light into the first polarized light
Implementation Method 4
The PBS prism and the half-wave plates are bonded together by use of an adhesive
Implementation Method 5
the adhesive is degraded through an oxidation process and a photochemical reaction process
Implementation Method 6
the adhesive is degraded through an oxidation process and a photochemical reaction process
Implementation Method 7
a drive mechanism that displaces the polarization converting element in one direction perpendicular to a polarization split direction in the polarization converting element
Data Source
AI summary
A first lens array splits light flux emitted from a light source. A second lens array is provided with a plurality of lens cells two-dimensionally arranged, on which light emitted from the first lens array is irradiated. A polarization converting element splits indefinite polarized light emitted from the second lens array into P polarized light and S polarized light, and conforms the split light to either the P polarized light or the S polarized light and emits the conformed light. A drive mechanism displaces the polarization converting element in a direction perpendicular to a polarization split direction along a surface on which the indefinite polarized light from the polarization converting element is incident.