Vehicle Mirror Backlight Unit with Directional Light Refraction
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Solution Overview
Problem
Conventional backlight units for vehicle outside mirrors face challenges in achieving uniform light distribution and luminous intensity control, leading to potential confusion between Blind Spot Monitoring (BSM) indicator flickering and assist turn signal flickering, especially in areas outside the driver's seat, where luminous intensity needs to be lower to prevent misinterpretation.
Innovation Solution
A backlight unit design incorporating a light source unit, a light processing unit with dispersed light paths and reflecting surfaces, and a light refraction unit with protrusions to refract light towards the driver seat, optimizing luminous intensity between the driver area and light leakage areas by adjusting the angle of the inclined surfaces in the light refraction unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the BSM indicator luminous intensity is increased to improve visibility for the driver, then the driver can clearly see the indicator, but light leakage to areas outside the vehicle increases causing confusion with assist turn signals
Solution Approach 1:
The patent applies local quality by creating different luminous intensity characteristics in different spatial regions. The light guide plate and reflecting plate are designed to direct light preferentially toward the driver area while suppressing light emission in light leakage areas. This is achieved through specific optical path design where the light guide plate has a first surface facing the driver and a second surface facing away, with the reflecting plate positioned to reflect light back toward the driver, creating localized high intensity where needed while maintaining low intensity in other areas.
Solution Approach 2:
The patent utilizes dimensional differentiation by establishing distinct spatial zones with different luminous intensity requirements. The driver area is defined as a first region requiring higher luminous intensity (0.4-0.6 cd), while light leakage areas are defined as second regions requiring lower luminous intensity (≤0.2 cd). This dimensional separation in space allows the indicator to simultaneously satisfy conflicting luminous intensity requirements in different directions.
2Object-generated harmful factors
If the BSM indicator luminous intensity is decreased in light leakage areas to prevent confusion, then assist turn signal misidentification is reduced, but the visibility and stability of the BSM indicator for the driver deteriorates
Solution Approach 1:
The patent implements local quality by designing the optical system to provide differentiated luminous intensity characteristics in different spatial locations. The light guide plate and reflecting plate configuration creates a localized high-intensity zone in the driver area while maintaining low-intensity characteristics in light leakage areas. This spatial differentiation allows the system to simultaneously achieve high visibility for the driver and minimal light leakage to external areas.
3Device complexity
If conventional nonreflecting direct-type or backside reflection-type backlight units are used, then the structure is simple, but favorable uniformity of light cannot be implemented due to light concentration
Solution Approach 1:
The patent applies parameter changes by modifying the optical path parameters and geometric configuration of the light guide plate and reflecting plate. The light guide plate is designed with specific dimensions and surface characteristics, and the reflecting plate is positioned at specific angles and distances to optimize light distribution. These parameter optimizations enable uniform light illumination across the indicator icon while maintaining structural simplicity, avoiding the need for complex multi-component assemblies.
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 solution effectively maintains a higher luminous intensity in the driver area while reducing it in light leakage areas, ensuring clear distinction between BSM indicator flickering and assist turn signal flickering, thereby enhancing driver visibility and safety.
Implementation Method 1
a light refraction unit stacked on a front surface of the light guide plate and configured to refract light illuminated from the front surface of the light guide plate toward a driver seat
Data Source
AI summary
A backlight unit 10 for an outside mirror of a vehicle may comprise: a light source unit 30 including at least one light source 31 disposed therein; a light processing unit 40 having at least one light passage 41 through which light emitted from the light source 31 passes while being diffused, and a reflective surface 42 for reflecting the light having passed through the light passage 41; and a photorefractive means 60 which is disposed at a light exit of the light processing unit and refracts light emitted from the light exit of the light processing unit to be oriented toward a driver's seat.