Multi-Channel Projection Display for Curved Surfaces

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Solution Overview

Problem

Existing projection systems face challenges in miniaturization due to brightness loss and increased system length when projecting onto curved or tilted surfaces, as they are designed for flat surfaces, leading to difficulties in achieving high-contrast and sharp images with minimal equipment and installation space.

Innovation Solution

A projection display system that generates individual images in a two-dimensional distribution across a non-planar free-form surface, using multi-channel optics to superimpose images in a way that constellations of points differ based on distance, allowing for correction of distances and maintaining image sharpness without increasing structural height or equipment complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If single-channel projection systems are used, then the system structure is simple, but the system length increases proportionally with the projection area, making miniaturization difficult

Engineering Contradiction:
Improvesystem structureVSAvoidsystem length
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The projection system is divided into multiple channels (e.g., three channels for RGB colors), with each channel having its own projection lens and image source. This segmentation allows the total projection area to be covered by multiple smaller projection units working in parallel, reducing the system length while maintaining the ability to project large areas.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from single-channel to multi-channel projection, adding the channel dimension to the system architecture. This allows the projection area to be expanded in the lateral dimension through multiple channels rather than increasing the system length in the optical path direction.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If known projection systems are miniaturized, then the system size is reduced, but brightness is lost in the projected image

Engineering Contradiction:
Improvesystem sizeVSAvoidprojected image brightness
Core Design Contradiction:
Volume of moving objectVSIllumination intensity

Solution Approach 1:

The system uses multiple image sources (one per channel) that can be positioned close to their respective projection lenses, minimizing the object distance. This allows miniaturization while maintaining brightness because each channel's light path is optimized independently with short distances between source and lens.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the object distance parameter by positioning image sources very close to the projection lenses (short object distance). This parameter change enables miniaturization while preserving brightness, as the close proximity compensates for the reduced system size through increased light intensity at the lens aperture.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If projection systems are used with curved or tilted surfaces, then adaptability is improved, but complex tilting mechanisms are required, increasing device complexity and installation space

Engineering Contradiction:
Improveprojection surface adaptabilityVSAvoidtilting mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic adaptability by allowing the image sources to be positioned at different distances from their respective projection lenses. This dynamic adjustment capability enables the system to adapt to tilted and curved surfaces without mechanical tilting mechanisms, as the focus and projection geometry can be optimized independently for each channel based on the actual surface orientation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses parameter changes in the object distance for each channel to adapt to different projection surfaces. By varying the distance between image sources and projection lenses, the system can compensate for tilted and curved surfaces without requiring mechanical tilting or complex adjustment mechanisms.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If increased f-number is used to increase depth of field, then the depth of field is improved, but light intensity decreases, causing brightness loss and hindering miniaturization

Engineering Contradiction:
Improvedepth of fieldVSAvoidlight intensity
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The patent changes the object distance parameter to a very small value, positioning image sources close to the projection lenses. This parameter change creates a situation where a small f-number can provide both sufficient depth of field and high light intensity, enabling miniaturization without the brightness loss that would normally result from using a small f-number.

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

Enables high-quality projection onto curved or tilted surfaces with comparable miniaturization and equipment complexity, maintaining image sharpness and contrast without the need for additional optical components or tilting mechanisms.

Implementation Method 1

a multi-channel optic configured to image one associated individual image or partial area of the image sensor per channel, such that the images of the individual images are at least partially superimposed on a projection surface to form a complete image

Methodology Applied
Scientific EffectOptical imaging: Lens

Implementation Method 2

The étendue, or light transmittance, of a light source is determined by the size of the light source. The étendue is determined by its luminous area A, the half-angle of divergence Θ, and the refractive index n, and remains constant for ideal optical imaging.

Methodology Applied
Scientific EffectLight transmission: Light

Data Source

PatentEP3712700B1Projection display and method for displaying an overall image for free-form projection surfaces or tilted projection surfaces
Publication Date: 2022.12.07 FRAUNHOFER GESELLSCHAFT ZUR FORDERUNG DER ANGEWANDTEN FORSCHUNG EV
  • EP3712700B1 patent drawingFigure 1
  • EP3712700B1 patent drawingFigure 2A~2B
  • EP3712700B1 patent drawingFigure 2C~2D

AI summary

A projection display with an image sensor is described, configured to generate individual images in a distribution, such as a two-dimensional distribution, of sub-areas of an image sensor's imaging plane, and a multi-channel optic configured to image one associated individual image or sub-area of ​​the image sensor per channel, such that the images are at least partially superimposed on a projection surface to form a complete image, the projection surface being a non-planar freeform surface, such as...a curved surface, and/or tilted relative to the imaging plane, and the image sensor is designed such that constellations of points in the partial images, which are superimposed by the multichannel optics at a respective common point in the overall image, differ depending on the distance of the respective common point in the overall image from the multichannel optics. Alternatively, the image sensor and multichannel optics are designed such that the contribution of each channel to the overall image varies spatially across the overall image depending on the distance of the respective common point in the overall image from the multichannel optics.