Linear Light-Guiding Unit With Protrusive Reflection Structure
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Solution Overview
Problem
The existing light emitting modules in contact image sensors suffer from reduced light usage near the light emitting diode due to its light emitting angle and field distribution, resulting in darker areas compared to other regions.
Innovation Solution
The proposed light emitting module incorporates a linear light-guiding unit with a step structure adjacent to the light incident surface and an arched light emitting structure, which decreases the distance of incident light to the reflection surface, shortening the reflection path and increasing light usage, while also incorporating a protrusive reflection structure to enhance light reflection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional light-guiding bar with flat bottom surface is used, then the structure is simple, but the light usage is reduced near the LED due to light emitting angle and field distribution
Solution Approach 1:
The bottom surface of the light-guiding bar is segmented into multiple reflective surfaces (first reflective surface, second reflective surface, third reflective surface) at different positions and angles. This segmentation allows light to be reflected at multiple stages, increasing the probability of light extraction and improving overall light usage efficiency.
Solution Approach 2:
Different regions of the light-guiding bar are given different optical properties. The bottom surface has specific reflective surfaces with defined angles, while the side surface has a light-emitting structure with microstructures. This local differentiation optimizes light extraction in different areas, particularly addressing the uneven light distribution near the LED.
2Use of energy by moving object
If the light-guiding bar has a long reflection path, then the structural dimensions are larger, but the light scattering increases and light usage decreases
Solution Approach 1:
The light-guiding bar is designed with pre-calculated reflection angles (first included angle between 15-35 degrees, second included angle between 10-50 degrees) for the reflective surfaces. This preliminary geometric design ensures that light follows an optimized path that minimizes scattering while maximizing extraction efficiency, reducing the need for long reflection paths.
Solution Approach 2:
The light-emitting structure on the side surface incorporates curved or arched configurations with microstructures. This curvature helps to focus and direct light extraction, reducing scattering effects and improving light usage efficiency without requiring excessively long reflection paths.
3Illumination intensity
If the light emitting angle of LED is narrow, then the field distribution is concentrated, but the area near the LED becomes darker compared to other areas
Solution Approach 1:
The light-guiding bar incorporates different optical structures at different locations: reflective surfaces on the bottom surface and a light-emitting structure with microstructures on the side surface. This local differentiation ensures that light is effectively extracted at various positions along the bar, creating more uniform illumination and reducing dark areas near the LED.
Solution Approach 2:
The invention transitions from a conventional single-surface light extraction approach to a multi-dimensional light extraction system. By adding reflective surfaces on the bottom surface and a light-emitting structure on the side surface, light can be extracted in multiple directions and dimensions, improving uniformity and reducing shadow effects near the LED.
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
This design increases light output efficiency, reduces scattering, and decreases total costs by concentrating outgoing light and improving light reflection, thereby addressing the issue of uneven light distribution.
Implementation Method 1
a light emitting unit, disposed on the light incident surface. The light emitting unit is configured to emit a light to enter the linear light-guiding unit through the light incident surface
Implementation Method 2
After the light emitted from the light source enters the light-guiding bar, the light is totally reflected and transmitted to the other end of the light-guiding bar
Implementation Method 3
the light is reflected by the protrusive reflection structure
Implementation Method 4
the light reflected by the protrusive reflection structure emits from the arched light emitting structure
Data Source
AI summary
The disclosure discloses a light emitting module, including: a linear light-guiding unit, including a light incident surface located on a side end thereof and a protrusive reflection structure disposed on a bottom side thereof; and a light emitting unit, disposed on the light incident surface. The light emitting unit is configured to emit a light to enter the linear light-guiding unit through the light incident surface, and the light is reflected by the protrusive reflection structure. On a side view, a first included angle is defined between the protrusive reflection structure and the bottom side, and the first included angle is greater than or equal to 15.0 degrees and equal to or less than 35.0 degrees.