Holographic Projector Feedback Control for Brightness Consistency

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Solution Overview

Problem

Current holographic projection systems face challenges in maintaining consistent brightness and color balance due to the diffractive nature of holographic processes, which can lead to visible changes in image quality during dynamic content display.

Innovation Solution

The implementation of a holographic projection system that uses a secondary image region for feedback control, allowing for closed-loop adjustments of optical power and color balance, ensuring consistent brightness and color balance in the primary image region through detection and feedback mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If holographic projection systems use diffractive processes to display dynamic content, then image content versatility is improved, but brightness consistency and color balance deteriorate

Engineering Contradiction:
Improveimage content versatilityVSAvoidbrightness consistency
Core Design Contradiction:
Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The patent implements a feedback control mechanism where a detector measures the actual brightness and color balance of the holographic image, and this measurement is fed back to a controller that adjusts the optical power and color balance in real-time to compensate for variations caused by dynamic content display

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically changes optical parameters (optical power and color balance) based on feedback measurements, allowing the holographic projection system to maintain consistent brightness and color balance while displaying different dynamic content

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If holographic projection systems use diffractive processes to display dynamic content, then image content versatility is improved, but color balance stability deteriorates

Engineering Contradiction:
Improveimage content versatilityVSAvoidcolor balance stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The detector measures color balance characteristics of the holographic image and feeds this information back to the controller, which adjusts color balance parameters in real-time to maintain stability despite dynamic content changes

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts color balance parameters based on feedback measurements, enabling stable color reproduction while displaying versatile dynamic content

Inventive Principle:
Principle #35Parameter changes

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 maintains consistent brightness and color balance in the primary image region, enhancing the overall quality and stability of the holographic projection, even with dynamic changes in content, by adjusting optical power and color balance in real-time based on feedback from the secondary image region.

Implementation Method 1

Each pixel of the spatial light modulator is individually addressable to independently modulate a corresponding portion of the incident light to form a computer-generated hologram

Methodology Applied
Scientific EffectPhase modulation: Phase Modulation

Implementation Method 2

Light scattered from an object contains both amplitude and phase information. This amplitude and phase information can be captured on, for example, a photosensitive plate by well-known interference techniques to form a holographic recording

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

The hologram may be reconstructed by illumination with suitable light to form a two-dimensional (replay image) or three-dimensional holographic reconstruction representative of the original object

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP3408709B1Holographic projector
Publication Date: 2024.06.05 DUALITAS LTD
  • EP3408709B1 patent drawingFigure 1
  • EP3408709B1 patent drawingFigure 2A
  • EP3408709B1 patent drawingFigure 2B

AI summary

There is provided a holographic projection system comprising a light receiving surface (125), a light source (110), a spatial light modulator (140) and a detector. The light source is arranged to output light. The spatial light modulator is arranged to receive the light from the light source and output spatially modulated light in accordance with a computer generated hologram addressed to the spatial light modulator to form an image on the light receiving surface, wherein the image (700) comprises a primary image region (710) comprising the information for a user and a secondary image region (720). The detector is arranged to detect the optical power of light travelling to or from the secondary image region of the image, wherein an active light detecting area of the detector and the secondary image region have a corresponding shape. In embodiments, the system allows optical alignment of the holographic reconstruction.