Dielectric Angle Filter for Spatial Light Modulator Diffraction
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Solution Overview
Problem
Existing optical systems, such as spatial light modulators, emit unnecessary light in angles different from the intended direction due to diffraction effects, degrading light quality.
Innovation Solution
An optical apparatus incorporating an angle filter with a dielectric multilayer film where layers of different refractive indices are alternately stacked, allowing control of transmittance and reflectance based on incident angle to selectively extract desired angular components and remove others.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a spatial light modulator is used for phase modulation, then light can be modulated according to pixel patterns, but unnecessary light is emitted in angles different from the intended emitting angle due to diffraction effects
Solution Approach 1:
The patent extracts and removes the harmful angular components (unnecessary light) from the light beam using an angle filter. The filter selectively transmits only the desired angular component while blocking other angles, effectively separating the useful light from the harmful diffraction-induced light.
Solution Approach 2:
The angle filter acts as an intermediary element between the spatial light modulator and the final light output. This mediator selectively allows desired angular components to pass while blocking unwanted ones, resolving the contradiction between maintaining modulation capability and eliminating harmful emissions.
2Object-generated harmful factors
If an angle filter is designed to selectively transmit specific angles, then light quality is improved, but the device complexity increases due to the dielectric multilayer film structure
Solution Approach 1:
The angle filter employs a dielectric multilayer film composed of alternating layers with different refractive indices. This composite structure enables precise control of angular selectivity through the refractive index differences and layer thicknesses, achieving high light quality improvement while managing the inherent complexity through systematic material composition.
Solution Approach 2:
The patent controls the angular transmission characteristics by adjusting parameters of the dielectric multilayer film, including layer thickness, number of stacked layers, and refractive index differences. By optimizing these parameters, the filter achieves desired angular selectivity with controlled complexity.
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 angle filter enhances light quality by selectively transmitting desired angular components and blocking unnecessary ones, improving the output of spatial light modulators.
Implementation Method 1
a transmittance and a reflectance of the dielectric multilayer film change according to an incident angle of light
Implementation Method 2
dielectric layers having a first refractive index and dielectric layers having a second refractive index lower than the first refractive index are alternately stacked
Implementation Method 3
an optical system for outputting parallel light
Data Source
AI summary
An optical apparatus includes an optical system for outputting parallel light, and an angle filter disposed on an optical path of the parallel light output from the optical system. The angle filter includes a dielectric multilayer film in which dielectric layers having a first refractive index n1 and dielectric layers having a second refractive index n2 lower than the first refractive index n1 are alternately stacked.