Light Modulating Device Macropixel Homogenization
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Solution Overview
Problem
Current spatial light modulators (SLMs) for holographic displays have limitations in controlling both amplitude and phase of light waves, leading to reduced resolution and increased noise due to limited quantization steps, which affects the quality of holographic reconstructions, especially when using binary SLMs with few quantization steps.
Innovation Solution
A light modulating device comprising a spatial light modulator (SLM) and a homogenizing element, where groups of adjacent SLM pixels form macropixels, and the homogenizing element ensures that the output light is equivalent to that of a single homogeneous pixel, reducing noise and increasing the usable diffraction angle by mixing the light output from multiple pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If binary SLMs with few quantization steps are used, then device complexity is reduced and switching speed is improved, but manufacturing precision and noise performance deteriorate
Solution Approach 1:
The patent divides each logical pixel into multiple physical sub-pixels (e.g., 2x2 or 3x3 arrangements). Each sub-pixel is independently controlled, allowing the system to achieve higher effective quantization levels by combining different states of sub-pixels. This segmentation enables binary SLMs to simulate multi-level modulation, resolving the contradiction between simple binary control and high precision requirements.
2Reliability
If multiple adjacent pixels are combined to form macropixels, then noise is reduced and diffraction angle is increased, but device complexity increases
Solution Approach 1:
The patent combines multiple adjacent pixels into macropixels that function as integrated optical elements. By merging the optical paths and control signals of individual pixels, the system achieves noise reduction through spatial averaging and increases the effective diffraction angle while maintaining manageable structural complexity through unified macropixel design.
3Manufacturing precision
If homogenizing elements are added to mix light output from multiple pixels, then noise is reduced and image quality is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent introduces homogenizing elements as intermediary optical components between the SLM and the holographic reconstruction space. These elements act as mediators that mix and homogenize light from multiple pixels, reducing noise and improving image quality without requiring fundamental changes to the core SLM architecture, thus managing the trade-off between quality improvement and system 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
This configuration enhances the quality of holographic reconstructions by reducing noise and increasing the diffraction angle, allowing for higher resolution and improved brightness, while also enabling faster switching times and higher frame rates for holographic displays.
Implementation Method 1
The homogenizing element is adapted such that output light of the macropixel is entering the optical input of the homogenizing element and is mixed within the homogenizing element and is output at the optical output of the homogenizing element
Implementation Method 2
The cells modulate the amplitude and/or phase of light by encoding hologram values corresponding to a video-hologram
Implementation Method 3
In order to ensure sufficient temporal coherence, the spectrum of the light emitted by the light source must be limited to an adequately narrow wavelength range, i.e. it must be near-monochromatic
Implementation Method 4
The spectral bandwidth of high-brightness LEDs is sufficiently narrow to ensure temporal coherence for holographic reconstruction
Implementation Method 5
a device for reconstructing three-dimensional scenes by way of diffraction of sufficiently coherent light
Data Source
AI summary
According to the invention, a light modulating device comprises a spatial light modulator (SLM) and a homogenizing element (2). A group of at least two adjacent pixels of the spatial light modulator form a macropixel (1) : The spatial light modulator is of a type such that its pixels comprise a variable content. Each macropixel is used to represent a numerical value which is manifested physically by the states of the pixels of the spatial light modulator which form the macropixel. For each macropixel a homogenizing element is present in the optical path after the macropixel. The homogenizing element comprises an optical input and an optical output. The homogenizing element is adapted such that output light of the macropixel is entering the optical input of the homogenizing element and is mixed within the homogenizing element and is output at the optical output of the homogenizing element. It is intended that the numerical values of all macropixels can be set in such a way as to modulate an incoming light wavefront in a predetermined manner by the use of the physical manifestation of the macropixels.