Head-Up Display Sunlight Shielding via Concave Mirror Geometry

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Solution Overview

Problem

Conventional head-up display devices are expensive and large due to the need for shutters or reflection type polarizing films to counteract sunlight, and there is a desire for miniaturization and cost reduction without using these components.

Innovation Solution

The design incorporates a head-up display device with a concave mirror and plane mirror configuration, where shielding plates are extended to the vicinity of the optical path to block sunlight, and the use of high thermal conductivity and heat-resistant materials for the shielding portions to effectively shield external light, along with anti-reflection treatments to prevent light from entering the display unit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shutter is used to block sunlight, then the display unit is protected from damage and sunlight interference, but the device becomes expensive and large

Engineering Contradiction:
Improveprotection from sunlight damageVSAvoiddevice size and cost
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the shutter component entirely from the system. Instead of using a mechanical shutter to block sunlight, the invention relies on the optical properties of the concave mirror and shielding plates to prevent sunlight from reaching the display unit, thereby eliminating the complexity and cost associated with shutters while maintaining protection.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces shielding plates as intermediary elements positioned between the sunlight source and the display unit. These plates, combined with the concave mirror geometry, act as mediators to block harmful sunlight without requiring a mechanical shutter mechanism.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If a reflection type polarizing film is used to prevent sunlight heating, then the display unit temperature is controlled, but the device becomes expensive and large

Engineering Contradiction:
Improvedisplay unit temperature controlVSAvoiddevice size and cost
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent eliminates the reflection type polarizing film from the system. The concave mirror and shielding plate configuration naturally prevents sunlight from reaching the display unit, removing the need for polarizing films and their associated cost and size penalties.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses the concave mirror's optical properties to redirect and concentrate display light effectively while simultaneously using the same mirror geometry combined with shielding plates to block harmful sunlight. The mirror's curvature becomes beneficial for both illumination and protection functions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If shielding plates are extended to the vicinity of the optical path, then sunlight is effectively blocked, but the device structure becomes more complex

Engineering Contradiction:
Improvesunlight blocking effectivenessVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent integrates the shielding plates with the existing housing structure and mirror mounting framework. The shielding plates are positioned to work in conjunction with the concave mirror and plane mirror, merging multiple functions (structural support, light blocking, and optical path definition) into a unified structure rather than adding separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shielding plates serve multiple functions: they block sunlight from reaching the display unit, define the optical path boundaries, and can be integrated with mounting structures. This multi-functionality reduces the need for additional dedicated components, thereby limiting the increase in structural complexity.

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

This configuration allows for effective sunlight shielding without the need for shutters or polarizing films, reducing the size and cost of the device while maintaining high heat resistance and optical performance.

Implementation Method 1

an optical element disposed within the housing and configured to concentrate the image information in a focal plane located in the region of the exit aperture... The optical element may be a concave mirror

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The optical element is designed to concentrate the light bundle in the direction of the exit aperture into a focal plane, so that the light bundle in the region of the exit aperture has an intermediate focus with a minimum extent

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

a mirror element, which is arranged outside the housing and is designed to mirror the image information in an optical path

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 4

the housing may further comprise a first shielding portion and a second shielding portion... capable of shielding external light entering to inside the housing from the outside of the housing and proceeding toward the concave mirror after being reflected by the mirror element

Methodology Applied
Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentEP3220186B1Head up display device
Publication Date: 2022.10.19 NIPPON SEIKI CO LTD
  • EP3220186B1 patent drawingFigure 1
  • EP3220186B1 patent drawingFigure 2
  • EP3220186B1 patent drawingFigure 3

AI summary

The problem addressed by the present invention is to provide a head up display device capable of counteracting sunlight without using a shutter or a reflection type polarizing film. A first concave mirror (14) has a curvature to cause the reflected display light (15) to intersect vertically before reaching a second mirror (16), and a second concave mirror (16) serves to reflect the received display light. A case (20) is provided with a first shield (23) and a second shield (24) extending near an intersecting point (22) to sandwich a light path (21) between the first and second concave mirrors (14, 16). The first and second shields (23, 24) can block external light (25) entering into the case (20) from outside the case (20) and proceeding toward the first concave mirror (14) after being reflected from the second concave mirror (16).