Odd-Phase Stepped Diffraction Grating for Laser TV Sparkle Noise
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Solution Overview
Problem
Existing diffraction gratings for reducing sparkle noise in laser TVs require multiple gratings with different grating periods for various wavelengths, increasing complexity and manufacturing costs, and are prone to intensity loss.
Innovation Solution
A single diffraction grating with a stepped structure and odd phase configuration, where each step's height is determined to induce a π phase difference between zero-order diffraction patterns of red, green, and blue light beams, minimizing sparkle noise by controlling spatial coherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multiple diffraction gratings with different grating periods are used for different wavelengths, then sparkle noise reduction is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple diffraction gratings with different grating periods into a single integrated diffraction grating structure. This single grating contains multiple grating periods that can simultaneously handle different wavelengths (red, green, and blue lasers), thereby reducing the number of separate components while maintaining the ability to reduce sparkle noise across all wavelengths.
Solution Approach 2:
The single diffraction grating is designed to perform multiple functions by accommodating different grating periods within its structure. It can simultaneously diffract and control multiple wavelengths of light (red, green, and blue), making it a universal component that replaces what would traditionally require multiple specialized gratings, thus reducing device complexity while maintaining sparkle noise reduction effectiveness.
2Object-affected harmful factors
If multiple diffraction gratings with different grating periods are used, then sparkle noise reduction is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple diffraction grating functions into a single manufactured component. By integrating multiple grating periods into one structure, the manufacturing process is simplified compared to producing and assembling multiple separate gratings, thereby reducing manufacturing cost while maintaining the capability to reduce sparkle noise for different wavelengths.
3Object-affected harmful factors
If multiple diffraction gratings are used, then sparkle noise reduction is improved, but optical axis alignment complexity increases
Solution Approach 1:
The patent combines multiple diffraction gratings into a single integrated structure, which eliminates the need for complex optical axis alignment between multiple separate components. The single grating structure maintains a fixed geometric relationship between its different grating periods, thereby simplifying optical alignment while preserving the ability to reduce sparkle noise across multiple wavelengths.
4Object-affected harmful factors
If ground glass plates are used to reduce sparkle noise, then sparkle noise is reduced, but light beam intensity is lost
Solution Approach 1:
The patent uses a diffraction grating as an intermediary component between the laser beam and the display screen. The grating selectively diffracts light to reduce coherence-related sparkle noise while maintaining higher transmissivity compared to ground glass plates, thereby reducing sparkle noise without causing significant intensity loss of the coherent light beams.
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 approach effectively reduces sparkle noise in laser TVs by minimizing intensity loss and simplifying manufacturing, while maintaining high transmissivity for coherent light beams, thereby improving productivity and throughput.
Implementation Method 1
a diffraction grating having a structure to control a sparkling phenomenon occurring in an image-reproducing apparatus due to a laser source
Implementation Method 2
each step's height is determined to induce a π phase difference between zero-order diffraction patterns of red, green, and blue light beams
Data Source
AI summary
A diffraction grating including a substrate, and a grating member formed on the substrate, the grating member having a stepped structure including steps, the number of which corresponds to an odd number greater than or equal to three to provide an odd phase structure. The heights of the steps of the grating member are determined such that the light beams diffracted by their corresponding steps substantially have a phase difference of π with reference to a diffracted light beam of a reference wavelength.