Variable Diffractive Structure for Holographic Observer Tracking
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Solution Overview
Problem
Holographic displays face challenges in tracking observer windows due to complex and costly beam tracking devices, limited angular range, and high pixel pitch requirements, making it difficult to achieve efficient and cost-effective observer window tracking.
Innovation Solution
A light modulator device with a diffraction device featuring a variable diffractive structure that alters the light wave field to deflect light beams towards the observer's eye position, allowing for precise tracking of observer windows using a control unit to adjust the diffractive structure and generate defined higher diffraction orders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a holographic display uses a spatial light modulator with a matrix arrangement of pixels to modulate light phase or amplitude, then the display can present two- and/or three-dimensional image content, but the pixel pitch must be relatively large (30-50 μm) to match the observer window size, which limits the angular range and tracking capability
Solution Approach 1:
The invention divides the light modulation function into two separate components: a spatial light modulator with large pixel pitch for presenting image content, and a diffractive optical element with fine periodic structure for angular deflection and tracking. This segmentation allows each component to be optimized independently, resolving the contradiction between large pixel pitch and limited angular range
Solution Approach 2:
The diffractive optical element acts as an intermediary between the spatial light modulator and the observer's eye. It takes the light modulated by the SLM and deflects it to the correct angular position based on observer location, enabling tracking capability without requiring the SLM itself to have fine pixel pitch
2Reliability
If complex beam tracking devices are used to track observer windows in holographic displays, then observer window tracking can be achieved, but the device complexity and cost increase significantly
Solution Approach 1:
The invention replaces complex mechanical beam tracking devices with a passive diffractive optical element that performs tracking through diffraction. The diffractive structure's periodic pattern naturally deflects light to different angular positions based on observer location, eliminating the need for active tracking mechanisms while maintaining reliable observer window tracking
Solution Approach 2:
The diffractive optical element performs tracking automatically based on the observer's position without requiring complex control systems. The diffraction physics inherently provides the tracking function by directing light to the correct angular position, making the system self-tracking
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
Enables efficient and cost-effective tracking of observer windows over a larger angular range with reduced complexity in manufacturing and addressing, allowing for the presentation of two- and three-dimensional image contents without the need for complex beam tracking devices.
Implementation Method 1
a diffraction device (20) with a variable diffractive structure, which diffracts the light wave field, which has been modulated by the light modulator, in a presettable way
Data Source
AI summary
The invention relates to a light modulation device for a display for representing two- and/or three-dimensional image content or image sequences. The light modulation device comprises a light modulator and a controller. The phase and/or the amplitude of a light wave field, which is substantially collimated, can be varied by means of the light modulator depending on the location of the light modulator. The light modulator can be actuated by means of the control device. According to the invention, in the direction of propagation of the light wave field, at least one diffracting unit is arranged downstream of the light modulator. The diffracting unit has a variable diffracting structure. By means of the diffracting structure, the light wave field varied by the light modulator can be diffracted in a variable and predeterminable manner. Further, the present invention relates to a display and a method for producing a light modulation device.