Microlens HUD Display Array for Wide Viewing Angle and Low Stray Light

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Solution Overview

Problem

Current vehicle-mounted head-up display systems face challenges due to complex structures, large volume, and stray light issues, limiting their wide application, especially with increasing HUD aperture sizes.

Innovation Solution

A display device comprising a display array generation device and a first lens layer with a beam splitting element, which provides collimated light beams parallel to each other, allowing for increased viewing angles and reducing the need for multiple collimating light sources and beam translation elements, thereby enhancing the display's field of view and reducing size and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a refractive-reflective optical system is used to achieve large exit pupil distance, large window size, and large viewing angle, then the viewing angle and field of view are improved, but the structure becomes complex and the volume increases

Engineering Contradiction:
Improveviewing angleVSAvoidstructure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The optical system is segmented into a light source unit, a beam splitting element, and a lens array unit. Each component performs a specific function: the light source generates light, the beam splitting element divides it into multiple beams, and the lens array focuses each beam to form an expanded virtual image. This segmentation simplifies the overall structure while achieving large viewing angles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple collimating light sources and beam translation elements are merged into a single light source and beam splitting element. The beam splitting element generates multiple collimated light beams from one source, and the lens array processes all beams to form the expanded virtual image, reducing system complexity and volume.

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If the HUD aperture size is increased to improve viewing angle, then the field of view is improved, but stray light problems worsen

Engineering Contradiction:
Improvefield of viewVSAvoidstray light
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

Each lens in the lens array has a specific function of focusing a corresponding collimated light beam to form a portion of the expanded virtual image. This localized processing ensures that light is precisely directed to the intended viewing areas, reducing stray light even as the overall aperture and field of view increase.

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If multiple collimating light sources and beam translation elements are used to achieve complete image display, then the image quality is improved, but the device size and weight increase

Engineering Contradiction:
Improveimage qualityVSAvoiddevice weight
Core Design Contradiction:
Manufacturing precisionVSWeight of stationary object

Solution Approach 1:

The beam splitting element serves multiple functions: it divides the light from a single light source into multiple collimated light beams, replacing the need for multiple separate light sources and beam translation elements. The lens array then processes all these beams to form the complete expanded virtual image, reducing device weight while maintaining image quality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution enables a wider viewing angle and complete image display even when the user's pupils are off-center, improving the display's field of view and resolution, making it suitable for head-up display systems and augmented reality applications.

Implementation Method 1

a beam splitting element, which provides collimated light beams parallel to each other

Methodology Applied
Scientific EffectLight splitting: Reflection

Implementation Method 2

the first lens layer includes a plurality of first lenses arranged in array and is configured to receive the plurality of collimated light beams. the plurality of collimated light beams correspond to the plurality of first lenses, so as to realize a plurality of scanning imaging

Methodology Applied
Scientific EffectLens focusing: Lens

Implementation Method 3

irradiating one surface of the photosensitive substrate by light outputted from the point light source, simultaneously, irradiating the other surface of the photosensitive substrate by the parallel light as a reference light, to allow the photosensitive substrate to record an interference pattern of the point light source and the reference light

Methodology Applied
Scientific EffectInterference: Interference

Implementation Method 4

obtaining a hologram including amplitude information and phase information of the point light source

Methodology Applied
Scientific EffectPhotography: Photography

Data Source

PatentEP3770668B1Display device, vehicle-mounted display system, vehicle, and holographic lens manufacturing method
Publication Date: 2024.08.28 BOE TECHNOLOGY GROUP CO LTD
  • EP3770668B1 patent drawingFigure 1A~1B
  • EP3770668B1 patent drawingFigure 2A~2B
  • EP3770668B1 patent drawingFigure 3A~3B

AI summary

A display device (100) and a vehicle (300) including the display device (100), a vehicle-mounted display system (200) and a method of manufacturing a holographic lens are provided. The display device (100) includes a display array generation device (110) and a first lens layer (120). The display array generation device (110) is configured to provide a plurality of collimated light beams (111) parallel to each other and spaced from each other; the first lens layer (120) is arranged at a light exiting side of the display array generation device (110). The first lens layer (120) includes a plurality of first microlenses (121) arranged in array, and is configured to receive a plurality of collimated light beams (111). The plurality of collimated light beams (111) correspond to the plurality of first microlenses (121), to achieve a plurality of scanning imaging, respectively. The display device (100) can be applied to head-up display systems.