Vehicle Projection Light Timing for Smooth Sequential Road Images

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Solution Overview

Problem

Existing projection systems for vehicles face limitations in creating a visual effect with sequential images due to restricted image divisions and cost/space constraints, making it difficult to effectively convey directional intentions to pedestrians and drivers.

Innovation Solution

A projection apparatus for vehicles that projects individual images sequentially, controlled by a timing signal, using multiple light sources and a control unit to synchronize lighting and projection periods, ensuring a smooth visual flow despite limited image divisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a head-up display is implemented in a motor vehicle, then driving safety and comfort are improved, but the device complexity and cost increase

Engineering Contradiction:
Improvedriving safetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the head-up display functionality with the existing vehicle headlight assembly, integrating the projection device into the headlight housing. This merging approach allows the head-up display to be implemented without adding separate, complex mounting structures, thereby improving driving safety while minimizing the increase in device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The headlight assembly is designed to serve multiple functions: traditional illumination and head-up display projection. By making the headlight assembly universal, the patent avoids adding dedicated hardware solely for head-up display purposes, thus improving safety information delivery while controlling device complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If the projection device is integrated into the headlight assembly, then the number of components is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvenumber of componentsVSAvoidalignment precision
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent incorporates alignment marks and positioning features directly into the mold tooling during the manufacturing process. This preliminary action ensures that the projection device is pre-aligned with the optical axis before final assembly, reducing the need for complex post-assembly adjustments and maintaining manufacturing precision while keeping the component count low

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent specifies precise geometric parameters and tolerances for the integration of the projection device into the headlight assembly. By controlling key parameters such as the position of the projection lens relative to the reflector and the alignment of optical axes through defined tolerances, the patent achieves the required manufacturing precision within standard manufacturing capabilities

Inventive Principle:
Principle #35Parameter changes

3Loss of information

If the projection device projects images onto the windshield, then driving information is improved, but the image quality may be affected by windshield curvature and position variations

Engineering Contradiction:
Improvedriving informationVSAvoidimage quality consistency
Core Design Contradiction:
Loss of informationVSManufacturing precision

Solution Approach 1:

The patent projects information onto a specific local area of the windshield (the lower central region within the driver's field of view) rather than attempting to cover the entire surface. This localized projection approach allows for optimized image quality in the critical viewing area while tolerating variations in other regions, thereby improving driving information delivery while maintaining consistent image quality

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent incorporates sensors to detect the position and curvature of the windshield, using this feedback information to dynamically adjust the projection parameters. This feedback mechanism compensates for variations in windshield position and curvature, ensuring consistent image quality and effective driving information delivery across different vehicle configurations

Inventive Principle:
Principle #23Feedback

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 effectively conveys directional intentions by smoothly projecting sequential images, enhancing visibility and recognition even with a limited number of images, improving safety by clearly indicating vehicle maneuvers.

Implementation Method 1

a light guide unit having a light incident surface on which light from the light source is incident and a side surface extending in a direction crossing the light incident surface, and redirecting the light from the light incident surface toward a direction away from the light source by total internal reflection at the side surface

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a projection device for a vehicle including a light source, a condenser lens, a reflection mirror, a light guide unit, and a projection lens

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP4349652B1Projection device for vehicle, method of operating same, and light fixture for vehicle
Publication Date: 2026.04.08 ICHIKOH IND LTD
  • EP4349652B1 patent drawingFigure 1
  • EP4349652B1 patent drawingFigure 2~3(c)
  • EP4349652B1 patent drawingFigure 4~5

AI summary

The present invention addresses the problem that the road surface area allowed for projecting an image is limited, there is a restriction on the number of parts into which the image can be divided, and it is hard to achieve an intended visual effect even if individual images are sequentially projected. A control unit (31) controls three light sources (21a to 21c) so that, among three individual images (5a to 5c), projection of an image (5b) to be projected second is started at a time point (t4) later than a time point (t3) at which a period of 250/3 milliseconds has elapsed from a projection start time point (t1) for an image (5a) to be projected first. Consequently, the visual effect of sequential projection of individual images is more easily achieved than when the projection of the second individual image (5b) is started at the time (t3).