Electrowetting Lens Array for Windshield Display Brightness

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Solution Overview

Problem

Existing windshield displays, such as those using fluorescent films, OLEDs, and LCDs, struggle to maintain visibility in bright sunlight due to insufficient brightness, and previous solutions like microlens arrays cause undesirable distortion.

Innovation Solution

An array of electrowetting lenses is overlayed on a transparent display, allowing lenses to switch between flat and shaped states to enhance light directionality and visibility, with electrowetting lenses adjacent to the display used to outline images against the background, thereby increasing apparent brightness and reducing distortion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a transparent display is applied to a windshield, then information can be displayed to the operator, but the display becomes difficult to see in bright sunlight

Engineering Contradiction:
Improveapparent brightness of displayVSAvoidambient light interference
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent employs electrowetting lenses that can dynamically change their shape between a flat state (for normal vision) and a shaped state (for enhancing display brightness). This dynamic adjustment allows the system to adapt to different viewing conditions, specifically increasing the apparent brightness of the display when needed while maintaining normal windshield visibility otherwise.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The electrowetting lenses change their optical parameters (shape, curvature) in response to electrical signals. When switched to the shaped state, the lenses alter their refractive properties to direct and concentrate light from the transparent display, thereby increasing its apparent brightness against the background of bright sunlight.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If microlens arrays are used to increase display brightness, then apparent brightness improves, but undesirable distortion is introduced

Engineering Contradiction:
Improveapparent brightness of displayVSAvoidvisual distortion
Core Design Contradiction:
Illumination intensityVSShape

Solution Approach 1:

Unlike fixed microlens arrays, the electrowetting lenses can dynamically switch between flat and shaped states. This dynamic capability allows the system to enhance display brightness when needed while maintaining a flat, distortion-free appearance during normal operation, thus avoiding the permanent distortion associated with fixed microlens arrays.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent extracts the lensing function from a fixed structure and implements it through controllable electrowetting elements. This allows the lensing effect to be applied only when necessary (during display operation) while removing the distortion problem associated with continuous lensing structures.

Inventive Principle:
Principle #2Taking out (Extraction)

3Illumination intensity

If electrowetting lenses are operated to increase display brightness, then apparent brightness improves, but device complexity increases

Engineering Contradiction:
Improveapparent brightness of displayVSAvoidlens array control system
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The electrowetting lenses are designed to respond automatically to electrical signals from the display control system. Once triggered, the lenses self-adjust their shape to the appropriate configuration without requiring manual intervention or complex mechanical control mechanisms, thereby reducing overall system complexity despite the advanced material technology used.

Inventive Principle:
Principle #25Self-service

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 effectively enhances the visibility of windshield displays in bright sunlight conditions while maintaining clear vision through the windshield, allowing operators to easily discern displayed information without distortion.

Implementation Method 1

an array of electrowetting lenses overlays the transparent display. Each lens of the array is operable to a flat-state where light passes through the lens substantially undistorted. Each lens of the array is also operable to a shaped-state where emitted light from an underlying portion of the transparent display is directed

Methodology Applied
Scientific EffectElectrowetting: Electrowetting

Implementation Method 2

The transparent display includes a fluorescent film layer configured to fluoresce where illuminated with suitable light effective to display an image on the fluorescent film layer

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP2607940B1Windshield display system using electrowetting lenses.
Publication Date: 2014.08.27 DELPHI TECHNOLOGIES INC
  • EP2607940B1 patent drawingFigure 1
  • EP2607940B1 patent drawingFigure 2

AI summary

A windshield display system for installation into a vehicle that includes a windshield (16), a transparent display (18) overlaying the windshield (16), and an array (24) of electrowetting lenses (26A, 26B) overlaying the transparent display (18). Each lens of the array (24) is operable to a flat-state where light (28B) passes through the lens (26B) substantially undistorted, and a shaped-state where emitted light (28A) from an underlying portion (30) of the transparent display (18) is directed in order to increase an apparent brightness of the emitted light (28A). The array (24) selectively magnifies pixels or portions of the transparent display (18), while maintaining vision clarity for the operator in regions of the windshield (16) where images are not being displayed. The array (24) may also outline or highlight images being displayed with a region of distortion of surrounding the image to distort the view of the scene outside the vehicle to help the operator discern the image when the outside lighting conditions are less than ideal.