Projection Display Illumination Optical System Light Density Management
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Solution Overview
Problem
The illumination optical systems in projection type display apparatuses using liquid-crystal display elements face issues with the longevity of optical components when employing light sources like light emitting diodes, as the high light density and energy from these sources can lead to premature wear and reduced light transmission, affecting the overall life of the display apparatus.
Innovation Solution
The design incorporates a light source with a solid emitting element, such as a light emitting diode or laser, combined with a polarization conversion integrator featuring a specific arrangement of polarized beam splitters and half-wave plates, and a diffusion layer to optimize light distribution and reduce light density on the polarization conversion element, ensuring uniform illumination and extending the life of optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a light emitting diode or laser is used as a light source, then light emission efficiency is improved, but the high light density and energy cause premature wear of optical components
Solution Approach 1:
A polarization conversion integrator is introduced as an intermediary component between the light source and the display element. This integrator includes a polarization conversion element with beam splitters and half-wave plates that diffuses and redistributes the light from the light emitting diode or laser, reducing the light density on any single point of the downstream optical components while maintaining overall illumination efficiency
Solution Approach 2:
The patent changes the polarization state of light multiple times through the use of beam splitters and half-wave plates arranged in specific configurations. By converting light between s-polarized and p-polarized states, the system redistributes light intensity and reduces concentration on specific optical components, thereby extending their lifespan
2Productivity
If the distance between array lenses is reduced to improve light transmission ratio, then illumination efficiency is improved, but the high energy density accelerates deterioration of the polarization conversion element
Solution Approach 1:
The polarization conversion integrator is segmented into multiple functional units including beam splitters and half-wave plates arranged in arrays. This segmentation allows the light to be processed through multiple stages, with each stage reducing the energy density on individual components while collectively maintaining high transmission efficiency
Solution Approach 2:
The patent uses a matrix arrangement of beam splitters and half-wave plates that processes light in multiple dimensions. By organizing the polarization conversion elements in a two-dimensional array rather than a single line, the light energy is distributed across more components, reducing the stress on each individual element
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 enhances the longevity of the illumination optical system by reducing light density on the polarization conversion element, thereby prolonging the life of organic members and maintaining high light utilization efficiency.
Implementation Method 1
a light source which includes a light emitting diode or a laser
Implementation Method 2
a polarization conversion integrator featuring a specific arrangement of polarized beam splitters and half-wave plates
Implementation Method 3
a diffusion layer to optimize light distribution and reduce light density on the polarization conversion element
Data Source
AI summary
A projection type display apparatus including a light source, a display element, an illumination optical system and a projection lens to project a magnified image of the optical image. The illumination optical system includes a first array lens and a second array lens, each includes a plurality of lens elements arranged in a matrix, each of the lens elements having a rectangular opening, and a polarization conversion element having polarization conversion function by use of a plurality of polarized beam splitters and a plurality of half-wave phase plates, arranged in an array and opposing to the lens elements of the second array lens, to emit predetermined polarized light. The light source includes a light emitting plane of a rectangle or an ellipse shape, a longitudinal direction of the light emitting plane being parallel to a longitudinal direction of each opening of the polarization conversion element.