LCOS Beam Modulator for Laser TV Brightness and Size
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Solution Overview
Problem
Existing laser TV projection systems face challenges in achieving miniaturization, low cost, and high brightness due to limitations in light source technology and light valve design, resulting in issues such as low display brightness, high cost, and the laser speckle effect.
Innovation Solution
A beam modulation apparatus using a polarizing beam splitter (PBS) prism and liquid crystal on silicon (LCOS) assemblies to modulate input light fields with different polarization states, combined with a light source apparatus that includes fluorescence plates and dichroic filters to generate white light fields, effectively reducing the number of lens elements and improving brightness and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-piece light valve is used to load RGB signals by time division, then the device complexity is reduced, but the display brightness and image quality deteriorate
Solution Approach 1:
The patent divides the single light valve into three separate light valves, each dedicated to a specific color channel (R, G, or B). This segmentation allows each light valve to be optimized for its specific wavelength, improving overall display brightness and image quality while maintaining manageable system complexity through specialized design.
2Illumination intensity
If the size of the light valve is increased to improve display brightness, then the brightness is improved, but the size of the projection lens and overall system becomes larger
Solution Approach 1:
The patent employs a folded optical path design that redirects light through multiple reflections and bends, effectively packing a longer optical path into a more compact spatial arrangement. This allows the use of smaller light valves while maintaining the required brightness, thereby reducing the overall system size without sacrificing display performance.
3Illumination intensity
If a three-piece light valve is used to respectively load RGB signals, then the display brightness and image quality are improved, but the number of lens elements increases and the projection lens becomes larger
Solution Approach 1:
The patent combines multiple optical functions into fewer optical elements. By using a folded optical path design, the system merges relay optics, beam steering, and image formation functions into a more integrated structure, reducing the total number of lens elements and simplifying the overall optical train despite using three separate light valves.
4Manufacturing precision
If green and red semiconductor laser diodes are used in a three-color pure laser source, then the image quality is improved, but the cost increases due to the limited availability and price of these laser diodes
Solution Approach 1:
The patent uses a single blue laser diode to generate all three color channels by exciting different phosphor materials. This approach creates optical copies of the laser light at different wavelengths (green and red) through phosphorescence, eliminating the need for expensive green and red laser diodes while maintaining high image quality and color accuracy.
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 solution enables a compact, cost-effective laser TV projection system with improved brightness and image quality by efficiently modulating light fields and reducing the number of lens elements, addressing the limitations of existing systems.
Implementation Method 1
The PBS prism is provided with an optical incident surface allowing the input light field to enter therethrough and an optical exit surface allowing the output light field to exit therefrom, and the interface of the PBS prism is configured to selectively allow a P-polarized incoming light to transmit therethrough and an S-polarized incoming light to reflect thereby.
Implementation Method 2
The LCOS assembly includes a first LCOS panel and a second LCOS panel. Each of the first LCOS panel and the second LCOS panel comprises a plurality of pixels over a reflective surface thereof, wherein each of the plurality of pixels is configured to be controllably switched on or off such that a polarity state of a light beam reflected by a portion of the reflective surface corresponding thereto is changed or remains unchanged.
Implementation Method 3
combined with a light source apparatus that includes fluorescence plates and dichroic filters to generate white light fields
Implementation Method 4
combined with a light source apparatus that includes fluorescence plates and dichroic filters to generate white light fields
Data Source
AI summary
Provided include a beam modulation apparatus for modulating an input light field and a projection system containing the apparatus. The input light field has a first light field and a second light field, having a difference of 90° in their polarization states. The apparatus includes a PBS prism, a first LCOS panel and a second LCOS panel. The first and the second LCOS panel are respectively over a side surface of the PBS prism opposing to an optical incident surface and an optical exit surface. Each LCOS panel comprises a plurality of pixels over a reflective surface thereof, with each pixel controllably switched on or off such that a polarity state of a light beam reflected by a portion of the reflective surface corresponding thereto is changed or remains unchanged. This beam modulation apparatus can be applied in a projection system, such as a laser TV projection system.