Vehicle Projection Unit Layout for Compact Mirror Integration

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Solution Overview

Problem

Conventional projection units for vehicles require more constructional space than available in vehicle parts like side mirrors, leading to integration challenges and image distortion when oriented parallel or perpendicular to the longitudinal vehicle axis.

Innovation Solution

A projection unit design with a reflective microdisplay rotated at an angle, combined with a reflector and lens units, allowing the projection unit to fit within limited space while maintaining image orientation and quality by ensuring even light distribution and polarization alignment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional projection unit is integrated into a vehicle part with limited space, then the available space is insufficient, but integration is prevented

Engineering Contradiction:
Improveconstructional spaceVSAvoidintegration capability
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent applies dimensional change by rotating the reflective microdisplay by 45 degrees relative to the light axis, transforming the optical path from a linear arrangement to a folded configuration. This allows the projection unit to fit into compact vehicle parts like side mirrors by utilizing angular space rather than linear space, effectively reducing the volume requirement while maintaining integration capability

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements nesting by integrating the projection unit within the housing of existing vehicle parts such as side mirrors. The optical components (light source, lenses, reflective microdisplay) are arranged in a compact nested configuration where each component is positioned within the limited space of the vehicle part housing, with the rotated microdisplay enabling efficient space utilization

Inventive Principle:
Principle #7Nested doll (Nesting)

2Device complexity

If the projection unit is oriented parallel or perpendicular to the longitudinal vehicle axis, then the construction is simplified, but image distortion occurs

Engineering Contradiction:
Improveconstructional arrangementVSAvoidimage orientation accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent resolves the contradiction by introducing a 45-degree rotation of the reflective microdisplay, which changes the orientation dimension of the optical system. This angular transformation allows the projection unit to be mounted in various orientations while maintaining correct image alignment, eliminating distortion without requiring complex additional optical elements or adjustment mechanisms

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent applies asymmetry by rotating the reflective microdisplay at a specific 45-degree angle rather than using symmetric parallel or perpendicular orientations. This asymmetric arrangement optimizes the optical path for compact mounting while preserving image quality, achieving a balance between simplified construction and precise image orientation

Inventive Principle:
Principle #4Asymmetry

3Volume of moving object

If the reflective microdisplay is rotated by an angle, then the available space is reduced, but image orientation and quality are maintained

Engineering Contradiction:
Improveconstructional spaceVSAvoidimage orientation
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The 45-degree rotation of the reflective microdisplay transforms the optical path into a folded configuration that fits within reduced volume while maintaining image orientation. The rotation angle is specifically chosen to optimize space utilization without compromising the alignment of projected images relative to the vehicle axis

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the orientation parameter of the reflective microdisplay from 0 or 90 degrees (parallel/perpendicular to light axis) to 45 degrees. This parameter change optimizes both the spatial configuration and optical performance, enabling compact integration while preserving image quality and correct orientation on the projection surface

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

Enables integration of the projection unit into vehicle parts without compromising image orientation or quality, achieving sharp, aligned projections relative to the vehicle axis.

Implementation Method 1

a first lens unit (14) for collecting the light emitted by the light source (12) along a first axis (A1)

Methodology Applied
Scientific EffectLight collection: Lens

Implementation Method 2

a reflector (28) for directing the light collected by the first lens unit (14) to the reflective microdisplay (32) along a second axis (A2)

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

a reflective microdisplay (32) for reflecting the light emitted by the light source (12)

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 4

a second lens unit (38) for collecting the light reflected by the reflective microdisplay (32) and for directing the collected light to a projection surface (42)

Methodology Applied
Scientific EffectLight collection and projection: Lens

Data Source

PatentEP4488752B1Projection unit of or for a vehicle, vehicle part and vehicle comprising such a projection unit
Publication Date: 2026.03.11 HELLA SATURNUS SLOVENIJA PROIZVODNJA SVETLOBNE OPREME ZA MOTORNA IN DRUGA VOZILA D O O
  • EP4488752B1 patent drawingFigure 1A~1B
  • EP4488752B1 patent drawingFigure 1C~2B
  • EP4488752B1 patent drawingFigure 2C~2D

AI summary

The present invention relates to a projection unit (491, 492, 493) of or for a vehicle (48), comprising a light source (12), a reflective microdisplay (32) for reflecting the light emitted by the light source (12), a first lens unit (14) for collecting the light emitted by the light source (12) along a first axis (A1), a reflector (28) for directing the light collected by the first lens unit (14) to the reflective microdisplay (32) along a second axis (A2), a second lens unit (38) for collecting the light reflected by the reflective microdisplay (32) and for directing the collected light to a projection surface (42), wherein the reflective microdisplay (32) is arranged inside the projection unit (491, 492, 493) rotated by a rotation angle (α) such that the row direction (DR) and/or the column direction (DC) are inclined to the first axis (A1. Further, the present invention is drawn to a vehicle part (44) and/or a vehicle (48) comprising such a projection unit (491, 492, 493).