Projector Optical Layout for Blue Light Valve Durability
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Solution Overview
Problem
Existing projectors face challenges in preventing the deterioration of liquid crystal light valves, particularly those modulating blue light, when increasing light source intensity to enhance brightness.
Innovation Solution
A projector design that includes a separation optical system with a first dichroic mirror to separate light into colored beams, a first light modulation element with a larger effective area than other elements, a reduction optical system to reduce luminous flux width, and a color combining prism to project a composite light beam, with the optical axis of the first light modulation element parallel to the reduction side imaging plane, and the incident direction of the first colored light beam opposite to its exit direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light source intensity is increased to make the projector brighter, then the illumination intensity is improved, but the liquid crystal in the blue light modulation element deteriorates faster
Solution Approach 1:
The patent introduces a reduction optical system that changes the dimensional distribution of light flux. By reducing the luminous flux width in the optical axis direction while maintaining the modulation element's effective area, the system redistributes the light energy density, thereby protecting the liquid crystal from excessive illumination intensity while maintaining projector brightness.
Solution Approach 2:
The patent changes the parameter of luminous flux width through the reduction optical system. By adjusting the luminous flux width parameter in the optical axis direction, the system achieves different illumination intensity distributions, allowing the projector to maintain brightness while reducing the harmful intensity on the liquid crystal molecules.
2Reliability
If the effective area of the blue light modulation element is increased to reduce illuminance, then the liquid crystal deterioration is prevented, but the device complexity increases
Solution Approach 1:
The reduction optical system serves multiple functions simultaneously: it reduces the luminous flux width, protects the liquid crystal from deterioration, and maintains the modulation element's effective area. This multi-functionality reduces the need for additional protective components, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent combines the reduction optical system with the existing optical path, merging the flux reduction function with the color separation and modulation functions. By integrating these functions into a unified optical system rather than adding separate protective devices, the overall device complexity is minimized.
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 design prevents liquid crystal deterioration in the first light modulation element by reducing illuminance and maintaining polarization direction, allowing for brighter projection without compromising the projector's performance.
Implementation Method 1
a first dichroic mirror configured to separate outgoing light emitted from the light source into a first colored light beam in a first wavelength band including blue light and another colored light beam longer in wavelength band than the first colored light beam
Implementation Method 2
a reduction optical system having an expansion side imaging plane on which the first light modulation element is disposed, and configured to reduce a luminous flux width of the first colored light beam on a reduction side imaging plane
Implementation Method 3
a color combining prism configured to emit a composite light beam obtained by combining the first colored light beam a luminous flux width of which is reduced by the reduction optical system, and the other colored light beam modulated by the second light modulation element with each other
Data Source
AI summary
A projector includes a separation optical system including a first dichroic mirror for separating outgoing light into a first colored light beam as a blue light beam and another colored light beam, a first light modulation element for modulating the first colored light beam, a second light modulation element for modulating the other colored light beam, a reflecting mirror for reflecting the first colored light beam from the first dichroic mirror, toward the first light modulation element, a reduction optical system for reducing a luminous flux width of the first colored light beam modulated by the first light modulation element, and a color combining prism. The effective area of the first light modulation element is larger than the effective area of the second light modulation element.