Projector Light Combining Unit Using Polarization Beam Splitter
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Solution Overview
Problem
Conventional 3D projectors waste more than half of the light energy due to inefficient light combining units, which reflect and transmit light beams, leading to suboptimal energy utilization.
Innovation Solution
The use of inner total reflective prisms in a splitting unit and a combining unit to split and combine light beams, along with modulating elements to control the traveling directions of the beams, ensuring that the energy of the first and second beams is sufficiently utilized by projecting them to specific image positions on a diffusing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional light combining unit is used to combine light beams from two light sources, then the light beams can be combined and projected, but more than half of the light energy is wasted due to reflection and transmission losses
Solution Approach 1:
The patent changes the optical parameters of the light combining unit by using a polarization beam splitter combined with a quarter-wave plate. This configuration transforms the light combination mechanism from conventional reflection/transmission (50% loss each) to a system where polarized light is selectively directed, significantly reducing energy waste while maintaining the beam combining function.
Solution Approach 2:
The light combining unit employs a composite optical system consisting of multiple components: a polarization beam splitter, a quarter-wave plate, and potentially other optical elements. This composite structure leverages the complementary properties of each component to achieve high efficiency light combination, where the polarization beam splitter separates light based on polarization state and the quarter-wave plate converts linear polarization to circular polarization, enabling near-complete light energy utilization.
2Productivity
If conventional beam splitting and combining methods are used, then light beams can be directed to projection, but light energy distribution efficiency is suboptimal
Solution Approach 1:
The patent employs time-sequential activation of light sources combined with polarization modulation. By alternating between first and second light sources and using the polarization beam splitter to direct their output to different screens, the system achieves efficient energy utilization through periodic operation, ensuring that each light source's energy is fully directed to its intended target without interference or loss.
Solution Approach 2:
The polarization beam splitter acts as an intermediary device that mediates between the two light sources and the projection screens. It receives light from either source and directs it to the appropriate screen based on the polarization state, enabling efficient energy distribution without direct interference between the two light paths. The quarter-wave plate further mediates by converting polarization states to enable full utilization of light energy.
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 approach effectively maximizes the use of light energy by projecting beams to precise image positions on a projection screen, enhancing the efficiency of the projector's light energy distribution and reducing waste.
Implementation Method 1
The splitting unit and the combining unit which are composed by inner total reflective prisms to split and combine light beams
Implementation Method 2
The splitting unit and the combining unit which are composed by inner total reflective prisms to split and combine light beams
Implementation Method 3
traveling directions of the light beams are controlled by first and second modulating elements
Implementation Method 4
pass through a first and a second position of the projection lens unit, imaged by a cylinder lens of the rear cylinder lens array, and are projected to a first image position and second image position
Data Source
AI summary
A projector is provided, including a first light source, a second light source, a splitting unit, a first modulating element, a second modulating element, a projection lens unit, a projection screen and a combining unit. The first light source provides a first beam in a first state. The second light source provides a second beam in a second state. The splitting unit receives the first beam and the second beam, splitting the first beam into a first sub-beam and a second sub-beam, and splitting the second beam into a third sub-beam and a fourth sub-beam. The first modulating element receives the first sub-beam and the third sub-beam from the splitting unit. The second modulating element receives the second sub-beam and the fourth sub-beam from the splitting unit. The combining unit respectively combines the first sub-beam and the second sub-beam, and combines the third sub-beam and the fourth sub-beam.