HUD Light Source Array Eye-Tracking Illumination

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Solution Overview

Problem

Existing head-up displays suffer from luminance uniformity issues and power wastage due to the way light beams are distributed, as they illuminate the entire eye-box regardless of the driver's eye position, leading to inefficient use of light sources.

Innovation Solution

A head-up display system with a plurality of light source elements, a transmission type display element, an optical member, and a viewpoint detector, where the light source elements are arranged in an array to output light beams that are deflected to illuminate a specific region of the display element, and the controller adjusts light intensity based on the observer's eye position, optimizing light distribution and reducing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If light source elements illuminate the entire eye-box region, then the driver can view the virtual image from any position, but power is wasted by illuminating regions where the driver's eyes are not located

Engineering Contradiction:
Improveviewing position flexibilityVSAvoidpower consumption
Core Design Contradiction:
Adaptability or versatilityVSUse of energy by moving object

Solution Approach 1:

The light source array is divided into multiple independently controllable light source elements arranged in an array shape. Each light source element corresponds to a specific region in the eye-box, allowing selective illumination of only the regions where the driver's eyes are currently positioned, thereby reducing power consumption while maintaining viewing flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the eye-box receive light from specific light source elements based on the detected eye position. The system provides localized illumination quality tailored to the driver's actual viewing position rather than uniform illumination across the entire eye-box, optimizing energy efficiency.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If all light source elements are activated, then sufficient luminance is provided across the entire eye-box, but luminance uniformity deteriorates due to inefficient light distribution

Engineering Contradiction:
ImproveluminanceVSAvoidluminance uniformity
Core Design Contradiction:
Illumination intensityVSStability of the object's composition

Solution Approach 1:

The viewpoint detector detects the driver's eye position in advance, and the controller pre-selects which light source elements to activate based on the detected position. This preliminary action ensures that only the necessary light source elements are activated to provide sufficient luminance uniformly across the region where the driver's eyes are actually located.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller dynamically changes the operational parameters (on/off state) of individual light source elements based on the detected eye position. By adjusting which light source elements are active, the system maintains optimal luminance uniformity across the relevant eye-box region while avoiding the luminance non-uniformity that would result from activating all light source elements.

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

The system achieves even luminance distribution within the eye-box, allowing the driver to recognize virtual images without luminance changes, while power is saved by selectively illuminating only the necessary regions, thereby improving efficiency and reducing energy usage.

Implementation Method 1

an optical member, wherein the plurality of light source elements output light beams, the transmission type display element displays an image, and the optical member deflects the light beams

Methodology Applied
Scientific EffectLight deflection: Reflection

Data Source

PatentEP3287834B1Head-up display and moving body comprising head-up display
Publication Date: 2019.08.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3287834B1 patent drawingFigure 1
  • EP3287834B1 patent drawingFigure 2
  • EP3287834B1 patent drawingFigure 3A

AI summary

A head-up display projects an image onto an eye-box of an observer. The head-up display includes a plurality of light source elements, liquid crystal panel (115), first lens (112), viewpoint detector (800), and controller (700). The plurality of light source elements are arranged into an array shape to output light beams. Liquid crystal panel (115) displays the image, and first lens (112) deflects the light beams emitted from the plurality of light source elements such that an identical region in an incident plane of liquid crystal panel (115) is illuminated with the light beams. Viewpoint detector (800) detects a viewpoint position of the observer. Controller (700) controls light intensity of the light source elements according to the viewpoint position detected by viewpoint detector (800).