Projector Light-Shape Adjusting Element for Stray Light Control
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Solution Overview
Problem
Conventional projectors suffer from decreased contrast and light extraction efficiency due to stray light caused by partial overlap of flat-state and on-state light beams, which is exacerbated by the use of shields to prevent stray light from entering the projection lens.
Innovation Solution
The projector incorporates a light-shape adjusting element, such as a biconic surface lens or cylindrical lens, within the light combination assembly to adjust the light beam into an elliptical shape, preventing overlap between useless and useful image beams and thus minimizing stray light, while maintaining high light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shield is disposed in the projector to block stray light, then image contrast is improved, but light extraction efficiency deteriorates
Solution Approach 1:
The light-shape adjusting element performs preliminary shaping of the light beam before it reaches the DMD, adjusting the light shape in advance to prevent stray light formation at the source rather than blocking it later with a shield
Solution Approach 2:
The patent changes the shape parameter of the light beam from circular to elliptical by using a light-shape adjusting element (cylindrical lens or biconic surface lens), which modifies the light distribution parameters to eliminate overlap between flat-state and on-state light beams
2Loss of energy
If the light beam shape is adjusted to elliptical, then stray light is prevented and light extraction efficiency is improved, but device complexity increases
Solution Approach 1:
A light-shape adjusting element (cylindrical lens or biconic surface lens) is introduced as an intermediary component in the light path to transform the light beam shape, serving as a simple optical element that achieves the desired effect without complex mechanisms
Solution Approach 2:
The patent employs a straightforward parameter change approach by using standard optical lenses (cylindrical or biconic) to transform the light beam from circular to elliptical, utilizing well-established optical components rather than inventing complex new 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
This solution effectively prevents stray light from reducing image contrast and enhances light extraction efficiency by ensuring that the pupil diagram of the image beam is adjusted to an elliptical shape, preventing partial overlap and maintaining high brightness and color balance.
Implementation Method 1
The light-shape adjusting element is disposed in the light combination assembly and located at the transmission path of the light beam for adjusting a light shape of the light beam, in which the light shape of the light beam is adjusted to be an elliptical shape
Implementation Method 2
the light-shape adjusting element is a biconic surface lens or a cylindrical lens
Data Source
AI summary
A projector includes at least one light source, a light combination assembly, a light-shape adjusting element, an illuminating assembly, and an imaging assembly. The light source is used for emitting at least one light beam. The light combination assembly is disposed at the transmission path of the light beam for transferring the light beam to an illumination beam. The light-shape adjusting element is disposed in the light combination assembly and located at the transmission path of the light beam for adjusting a light shape of the light beam, in which the light shape of the light beam is adjusted to be an elliptical shape. The imaging assembly is disposed at the transmission path of the illumination beam for transferring the illumination beam to an image beam. The imaging assembly is disposed at the transmission path of the image beam for projecting the image beam.