Illumination System with Beam Splitting Module for Projection Uniformity
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Solution Overview
Problem
Current optical path architectures for projection devices face challenges in reducing volume and enhancing efficiency due to additional loops required for blue light transmission, leading to issues with excess and uneven energy distribution, particularly with blue light, which affects the uniformity and brightness of projected images.
Innovation Solution
An illumination system integrating red and blue light elements into a single light emitting module, utilizing a beam splitting/combining module with reflective and beam splitting elements to ensure symmetrical speckle distribution on the light entrance surface of the light uniforming element, allowing for parallel transmission of red and blue light beams, thereby enhancing light uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If additional loops are used for blue light transmission paths, then blue light can be transmitted, but the volume of the light combining system increases
Solution Approach 1:
The patent combines red and blue light transmission paths into a single integrated optical path, eliminating the need for separate additional loops for blue light. The light emitting module integrates multiple light sources (red and blue LEDs) that emit light in different directions, which are then combined through a light guide plate to form a unified illumination path, thereby reducing system volume.
Solution Approach 2:
The patent utilizes the directional emission characteristics of different colored LEDs (red LEDs emit in one direction, blue LEDs emit in another direction) and employs a light guide plate with specific optical structures to redirect and combine these light paths in a two-dimensional plane, effectively merging what would traditionally require separate three-dimensional loops into a compact planar structure.
2Adaptability or versatility
If fluorescent powders are used to generate other color lights, then color diversity is achieved, but energy efficiency decreases due to filtering requirements
Solution Approach 1:
The patent extracts and eliminates the filtering step from the traditional fluorescent powder-based color generation process. Instead of using fluorescent powders that require excitation light and subsequent filtering, the invention directly uses LEDs that emit the desired colors in their primary emission directions, removing the energy-wasting filtering component from the system.
Solution Approach 2:
The patent replaces the mechanical/optical filtering system (filter wheels, dichroic mirrors) with a direct directional emission approach using specially oriented LEDs. This substitution eliminates the need for moving or complex optical filtering components, thereby improving energy efficiency while maintaining color diversity.
3Illumination intensity
If blue light with higher energy is used, then brightness is improved, but energy distribution becomes excessive and uneven
Solution Approach 1:
The patent applies different directional emission characteristics to different colored LEDs based on their specific properties. Blue LEDs, which have higher energy and tend to create uneven distribution, are positioned and oriented to emit in specific directions that complement the red LED emission patterns. The light guide plate incorporates local optical structures that redirect blue light to achieve uniform overall energy distribution across the illumination area.
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 configuration achieves symmetrical speckle distribution and improved light uniformity, enabling the integration of light emitting elements into a single module and enhancing the overall brightness and color consistency of projected images.
Implementation Method 1
At least one light beam among the plurality of red light beams and the plurality of blue light beams is reflected by the at least one reflective element and the at least one beam splitting element
Implementation Method 2
The beam splitting/combining module includes at least one beam splitting element and at least one reflective element
Data Source
AI summary
An illumination system and a projection device, including a light emitting module, a light uniforming element, and a beam splitting/combining module, are provided. The light emitting module includes red and blue light elements. The light uniforming element has an optical axis and a light entrance surface. The beam splitting/combining module is disposed on a transmission path of at least one blue light beam, is located between the light emitting module and the light uniforming element, and includes at least one beam splitting element and at least one reflective element. At least one among the red and the blue light beams is reflected by the reflective element and the beam splitting element. The red and blue light beams are transmitted to the light uniforming element in a direction parallel to the optical axis, and a speckle distribution on the light entrance surface is symmetrical with respect to the optical axis.