Vehicle Display Dual Concave Mirror Optical Extension

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Solution Overview

Problem

Conventional electronic rearview mirrors are bulky and prone to distortion, obstructing the field of view and requiring a compact design that minimizes visibility issues while maintaining image quality.

Innovation Solution

A vehicle display system incorporating a pair of concave mirrors and a display, where the display surface is positioned within the composite focal length of both mirrors, extending the virtual image distance for the driver and optimizing curvature and incidence angles to suppress distortion and allow downsizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electronic mirror is disposed in the upper middle portion at the front of the vehicle interior, then it can display the rear view video, but it blocks the field of view on the front side

Engineering Contradiction:
Improverear view display functionVSAvoidfield of view blocking
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The optical system is segmented into multiple components: a display unit, a first concave mirror, and a second concave mirror. This segmentation allows the light path to be folded and the virtual image to be formed at an extended distance, reducing the physical footprint of the device and minimizing obstruction of the driver's field of view while maintaining the rear view display function.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the electronic mirror is downsized, then it reduces field of view blocking, but it increases the occurrence of distortion

Engineering Contradiction:
Improvedevice sizeVSAvoidimage distortion
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent employs two concave mirrors with specifically designed curved reflecting surfaces. The first concave mirror has a curvature radius R1, and the second concave mirror has a curvature radius R2 where 0.95 ≤ R2/R1 ≤ 1.05. This spherical curvature design allows the mirrors to focus and redirect light rays while maintaining image quality and suppressing distortion, even in a compact configuration.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent optimizes the ratio of curvature radii between the two concave mirrors (R2/R1 within 0.95-1.05) and positions the display surface within the composite focal length of both mirrors. By carefully controlling these optical parameters, the system achieves a balance between compact size and minimal image distortion.

Inventive Principle:
Principle #35Parameter changes

3Volume of stationary object

If a compact configuration is achieved, then device size is reduced, but image quality and distortion control become more difficult

Engineering Contradiction:
Improvehousing sizeVSAvoidoptical alignment precision
Core Design Contradiction:
Volume of stationary objectVSManufacturing precision

Solution Approach 1:

The patent combines the display unit and the dual concave mirror optical system into an integrated electronic mirror assembly. The display surface is positioned within the composite focal length of both mirrors, merging the light source and optical elements into a compact unit. This integration reduces the overall housing volume while maintaining precise optical relationships through careful design of the mirror curvatures and their relative positioning.

Inventive Principle:
Principle #5Merging (Combining)

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 a compact configuration with reduced distortion, enhancing visibility and allowing for a smaller housing size without compromising image quality.

Implementation Method 1

a first concave mirror (6) having a reflecting surface formed in a concave shape and configured to reflect the video displayed in the display (5)

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a second concave mirror (7) having a reflecting surface formed in a concave shape and configured to reflect the video reflected on the first mirror (6)

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 3

a distance from eye point of occupant of vehicle to a reflecting image formed by the second mirror is optically extended such that it becomes longer than a distance from the eye point of the occupant to a display surface of the display

Methodology Applied
Scientific EffectOptical extension: Reflection

Data Source

PatentEP3683096B1Display apparatus for vehicle and display system for vehicle
Publication Date: 2022.05.04 JVC KENWOOD CORP
  • EP3683096B1 patent drawingFigure 1
  • EP3683096B1 patent drawingFigure 2
  • EP3683096B1 patent drawingFigure 3~4

AI summary

A vehicle display device (4) includes a display (5) configured to display a video; a first mirror (6) configured to reflect the video displayed in the display (5); and a second mirror (7) configured to reflect the video reflected on the first mirror (6), wherein a distance from eye point of occupant of vehicle to a reflecting image formed by the second mirror (7) is optically extended such that it becomes longer than a distance from the eye point of the occupant to a display surface (51) of the display (5) .