Plastic Rear View Mirror with Integrated Blind Spot Indicator
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Solution Overview
Problem
Conventional glass rear view mirrors are heavy, difficult to form into complex shapes, prone to shattering, and have issues with reflective coatings on plastic substrates, which tend to craze and fail environmental tests, while existing blind spot indicators do not effectively direct light to the driver's eyes in a cost-efficient manner.
Innovation Solution
A side rear view mirror assembly with a plastic mirror that integrates a blind spot indicator with a light source and light guide into the mirror's second surface, allowing the light to be directed to the driver's eyes, and uses a diffuser or total internal reflection lens to ensure visibility without interference fringes, while maintaining durability and passing automotive tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If glass is used for rear view mirrors, then durability and reflective coating stability are improved, but weight increases and complex shaping becomes difficult
Solution Approach 1:
The patent replaces traditional glass mirrors with plastic mirrors that have a shorter service life but are easier to manufacture and lighter. The plastic substrate is intentionally designed to be replaceable, accepting that it will degrade faster than glass in exchange for weight reduction and manufacturing flexibility.
Solution Approach 2:
The patent uses composite material structures by combining plastic substrate with specialized reflective coatings and protective layers. This creates a multi-layer composite that provides the necessary durability and optical properties while maintaining the weight advantages of plastic.
2Strength
If glass is used for rear view mirrors, then structural strength is improved, but ease of forming complex shapes deteriorates
Solution Approach 1:
The patent changes the material parameter from glass to plastic, which fundamentally alters the manufacturability. Plastic can be injection-molded into complex aspheric shapes directly, eliminating the need for complex grinding and polishing processes required for glass, while maintaining sufficient strength for mirror applications.
Solution Approach 2:
The patent accepts reduced structural strength and shorter service life of plastic compared to glass, in exchange for the ability to easily manufacture complex shapes through injection molding, thereby simplifying the manufacturing process.
3Illumination intensity
If reflective coating is applied to front surface of plastic mirror, then reflectivity is improved, but crazing and environmental test failure increase
Solution Approach 1:
The patent inverts the conventional approach by applying the reflective coating to the rear surface of the plastic mirror instead of the front surface. This protects the coating from environmental exposure and prevents crazing, while the plastic's optical properties direct light appropriately for mirror functionality.
Solution Approach 2:
The patent introduces the plastic substrate as an intermediary layer between the environment and the reflective coating. By placing the coating on the rear surface and using the plastic as a mediator, the coating is protected from direct environmental exposure that would cause crazing and failure.
4Loss of information
If blind spot indicator is added to mirror assembly, then blind spot detection capability is improved, but device complexity increases
Solution Approach 1:
The patent merges the blind spot indicator function with the mirror assembly by integrating the indicator into the mirror housing or mounting structure. This combines multiple functions (mirror reflection and blind spot indication) into a single integrated unit, reducing overall system complexity.
Solution Approach 2:
The patent makes the mirror assembly multi-functional by adding blind spot detection capability to the existing mirror structure. The same assembly that provides rear-view reflection also provides blind spot warning, eliminating the need for separate components and reducing overall system complexity.
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 provides a lightweight, durable plastic mirror assembly that effectively indicates blind spots to the driver, enhancing safety and aesthetics while meeting automotive testing standards, and is designed for easy and cost-efficient production.
Implementation Method 1
uses a diffuser or total internal reflection lens to ensure visibility without interference fringes
Implementation Method 2
uses a diffuser or total internal reflection lens to ensure visibility without interference fringes
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a plastic mirror (54) for automotive use having a shape that fits to a mirror housing (42) of a mirror assembly attached to a vehicle and having a first surface (56) at least coated with reflective material and a second surface with attachment means (52) wherein an optical element (66) is integrally formed in the plastic mirror's second surface (65).