Projector Illuminator With Vibrating Lens Array for Speckle Reduction
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Solution Overview
Problem
Existing projectors using laser light sources struggle with insufficient speckle noise reduction, despite configurations like combining three color laser beams and passing through a transmissive diffuser plate.
Innovation Solution
An illuminator design incorporating a first and second light source with different wavelength bands, a light combining member, a diffuser, a light collector, a collimator, a light homogenizer with integrated lens array surfaces, a vibration generator, and a superimposing lens to reduce speckle noise by vibrating the lens array surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If three color laser beams are combined and passed through a transmissive diffuser plate, then speckle noise is reduced, but the reduction is insufficient
Solution Approach 1:
The patent segments the illumination light into multiple wavelength bands using separate laser light sources (e.g., red, green, blue lasers) instead of using a single broad-spectrum source. Each wavelength band is independently controlled and combined, allowing for more effective speckle noise reduction through the segmented approach to light generation.
Solution Approach 2:
The patent introduces a vibration generator that dynamically vibrates the diffuser plate at specific frequencies. This dynamic vibration changes the diffuser plate's position and orientation over time, which modulates the speckle pattern and reduces the perceived speckle noise in the projection image.
2Object-affected harmful factors
If a diffuser plate is used to reduce speckle noise, then some noise reduction is achieved, but image quality may be degraded
Solution Approach 1:
The patent changes the physical parameters of the diffuser plate by vibrating it at controlled frequencies and amplitudes. This dynamic parameter change allows the system to optimize the balance between speckle noise reduction and image quality maintenance, as the vibration modifies the light diffusion characteristics without permanently degrading the image.
Solution Approach 2:
The vibration generator applies periodic vibration to the diffuser plate, creating time-varying speckle patterns that average out over time. This periodic action reduces the static speckle noise while maintaining image quality, as the human eye perceives the time-averaged pattern rather than individual speckle realizations.
3Illumination intensity
If laser light sources with wide color gamut are used, then projector performance is enhanced, but speckle noise generation increases
Solution Approach 1:
The patent segments the wide color gamut illumination into distinct laser wavelength bands (red, green, blue) that are independently generated and combined. This segmentation allows each laser to operate at its optimal wavelength for maximum efficiency and color purity, while the separate control of each band enables targeted speckle reduction strategies.
Solution Approach 2:
The patent uses dynamic vibration of the diffuser plate to counteract the speckle noise inherently generated by the coherent laser light sources. The vibration modulates the speckle pattern in real-time, allowing the system to maintain the high color gamut benefits of laser sources while reducing their speckle noise drawback.
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 design effectively reduces speckle noise in projection images by vibrating the lens array surfaces, ensuring uniform illumination and high-quality image projection without degrading image quality.
Implementation Method 1
a diffuser including a substrate having a diffuser surface that diffuses the combined light incident thereon and outputs the diffused combined light
Implementation Method 2
a vibration generator that vibrates the light homogenizer
Implementation Method 3
a light collector that is disposed between the light combining member and the diffuser, collects the combined light, and directs collected combined light toward the diffuser
Implementation Method 4
a collimator that parallelizes the combined light outputted from the diffuser
Data Source
AI summary
An illuminator includes a first light source that outputs first light having a first wavelength band, a second light source that outputs second light having a second wavelength band different from the first wavelength band, a light combining member that combines the first light and the second light with each other and outputs combined light, a diffuser that diffuses the combined light incident thereon, a light collector that collects the combined light and directs collected combined light toward the diffuser, a collimator that parallelizes the combined light outputted from the diffuser, a light homogenizer having a first lens array surface on which the combined light outputted from the collimator is incident and a second lens array surface integrated with the first lens array surface, a vibration generator that vibrates the light homogenizer, and a superimposing lens that superimposes light fluxes outputted from the light homogenizer on one another.