Automotive LED Lighting Unit with Multi-Reflection Lens for Thin Profile
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Solution Overview
Problem
Conventional linear light source units with LED and plate-like lens bodies face challenges in achieving weight reduction and efficiency while maintaining light usage efficiency, often requiring increased lens thickness for better light emission, which complicates layout design and weight savings.
Innovation Solution
A lighting unit design that reduces lens thickness by utilizing a first optical system with lens sections, air layers, and total reflection surfaces to direct light toward the front and rear surfaces, allowing for efficient light usage and parallel light emission with uniform intensity, and aligning the optical axes of the LED and lens for easier layout.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the LED light source is placed to face a side surface of the lens body to form a linear light source, then the light emission efficiency is improved, but the lens body thickness must be increased to increase the light incident surface area
Solution Approach 1:
The patent transitions from a conventional single-pass light path to a multi-pass optical system by introducing rear-side light incident surfaces. Light that would normally exit the front surface is redirected through total internal reflection to enter the lens body again from the rear side, creating a second optical path dimension. This allows increased light interaction with the lens material without increasing thickness.
Solution Approach 2:
The patent makes light interaction with the lens body continuous by enabling light to pass through the lens multiple times. The rear-side light incident surfaces capture light that would otherwise be lost and redirect it through the lens body again, ensuring continuous useful optical action rather than single-pass transmission. This multi-pass system maintains or enhances light efficiency while keeping thickness minimal.
2Productivity
If the lens body thickness is increased to enhance light usage efficiency, then the light incident surface area is increased, but the weight of the lens body increases
Solution Approach 1:
Instead of increasing thickness in the vertical dimension, the patent utilizes the rear-side surface dimension to create additional optical paths. By positioning light incident surfaces on the rear side of the lens body, the system achieves enhanced light interaction through spatial rearrangement rather than material accumulation, thereby avoiding weight increase.
Solution Approach 2:
The patent ensures continuous light usage efficiency through multiple passes of light through the lens body without requiring increased thickness. The rear-side light incident surfaces continuously redirect light back through the lens, maximizing the utilization of existing lens material and maintaining minimal weight.
3Shape
If optical axes of the lens body and LED light source are arranged to cross at right angles, then the light exiting surface can form a linear light source, but the layout design of the lamp becomes difficult
Solution Approach 1:
The patent segments the optical path into distinct functional zones: front-side light incident surfaces for initial light entry, rear-side light incident surfaces for light redirection, and designated light exiting surfaces. This segmentation allows the optical axes to be aligned collinearly for ease of manufacture while still achieving linear light source formation through the segmented optical paths and total internal reflection mechanisms.
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 enables a lighter and thinner lens body that maintains or exceeds the light efficiency of conventional designs, allows for parallel light emission, and simplifies layout alignment, while using 100% reflectance surfaces for enhanced light usage compared to traditional reflective surfaces.
Implementation Method 1
a lens body (30) including a first optical system (31)... allowing the ray of light to travel toward the front and rear surfaces of the lens body to enter the lens body again
Implementation Method 2
first total reflection surfaces (31c), second total reflection surfaces (31d)... using 100% reflectance surfaces for enhanced light usage
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
A lighting unit (10) can utilize a lens body (30) which is smaller in thickness and lighter in weight than a conventional lens body (30), and which can achieve efficiency of use of light comparable to or higher than efficiency achieved by the conventional lens body (30). The lighting unit (10) can include an LED light source (20), and a lens body (30) with a first side surface (30a) functioning as a light exiting surface having a substantially rectangular shape greater in width than in thickness, and a second side surface (30b) opposite the first side surface (30a). The LED light source (20) can be arranged to face the second side surface (30b) such that a ray of light emitted in a wide angle direction with respect to an optical axis (AX) of the LED light source (20) travels toward the front and rear surfaces of the lens body (30), and that a ray of light emitted in a narrow angle direction with respect to the optical axis (AX) enters the lens body (30) through the second side surface (30b). The lens body (30) can include a first optical system (31), a second optical system (32), and a third optical system (33). The first optical system (31) can include: a lens section (31a) formed on the front or rear surface of the lens body (30); a first light incident surface (31b) arranged in an optical path of the ray of light collected by the lens section (31a); a first total reflection surface (31c) arranged in an optical path of the ray of light having entered the lens body (30) through the first light incident surface (31b); and a second total reflection surface (31d) arranged in an optical surface of the reflected ray of light having reflected totally off the first total reflection surface (31c). The second optical system (32) can include: a second light incident surface (32a) formed on the second side surface (30b); a third total reflection surface (32b) arranged in an optical path of the ray of light collected by the second light incident surface (32a) and having entered the lens body (30); and a fourth total reflection surface (32c) arranged in an optical path of the ray of light having reflected totally off the third total reflection surface (32b). The third optical system (33) can include a third light incident surface (33a) for causing a ray of light emitted from the LED light source (20) in a wide angle direction with respect to the optical axis (AX) and in the direction of the width of the lens body (30) to enter the lens body (30), and a fifth total reflection surface (33b) for causing the ray of light having entered the lens body (30) through the third light incident surface (33a) to reflect totally to exit as a ray of light substantially parallel to the optical axis (AX) through an intermediate region between the central region (31e1) and the outermost region (31e2) of the first side surface (30a) functioning as the light exiting surface. An air layer for causing the ray of light collected by the lens section (31a) to pass therethrough is formed between the lens section and the first light incident surface (31b).