Projection Display Unit Transmittance Adjuster for Detection Accuracy
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Solution Overview
Problem
Projection display units with detection functions face issues of uneven signal intensity due to the application of invisible light, leading to degraded detection accuracy.
Innovation Solution
A projection display unit configuration that includes a projection optical system, a polarization separation device, and a detection optical system with a transmittance adjuster, such as a blocking plate or partially-transmitting mask, to adjust the transmittance of light rays and reduce unevenness in signal intensity on the imaging device's light reception surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single projection lens is used for both image projection and detection invisible light reception, then the configuration is simple and accurate object detection is achieved without calibration, but signal intensity becomes uneven in the light reception surface leading to degraded detection accuracy
Solution Approach 1:
The patent divides the optical system into separate projection and detection paths. The projection lens handles image projection while the detection optical system handles invisible light reception. This segmentation allows each subsystem to be optimized independently, resolving the contradiction between simple configuration and detection accuracy.
Solution Approach 2:
The patent introduces a transmittance adjuster as an intermediary component in the detection optical path. This adjuster compensates for uneven signal intensity by modifying the light transmission characteristics, thereby improving detection accuracy without complicating the overall system configuration.
2Measurement precision
If the imaging device is positioned optically conjugate with the light valve for accurate detection, then object detection accuracy improves, but signal intensity unevenness persists due to invisible light application distribution
Solution Approach 1:
The transmittance adjuster applies local corrections to different regions of the optical path. By varying the transmittance characteristics across the light reception surface, it compensates for the uneven invisible light application distribution while maintaining the optically conjugate positioning for accurate detection.
3Device complexity
If no transmittance adjustment is made, then the system configuration remains simple, but signal intensity unevenness degrades detection accuracy
Solution Approach 1:
The transmittance adjuster serves as a minimal intermediary component that provides the necessary signal intensity correction. It is positioned in the detection optical path between the polarization separation device and the imaging device, offering a simple yet effective solution to improve detection accuracy without significantly complicating the system.
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 improves detection accuracy by ensuring even signal intensity across the light reception surface, enhancing the ability to accurately detect objects without the need for complex calibration processes.
Implementation Method 1
The polarization separation device separates entering light into a first polarized component and a second polarized component
Implementation Method 2
The light valve modulates illumination light supplied from the illuminator on the basis of an image signal
Implementation Method 3
a projection lens, and a light valve that modulates illumination light supplied from the illuminator on the basis of an image signal, and outputs the modulated illumination light toward the projection lens
Implementation Method 4
The imaging device receives, via the projection lens and the polarization separation device, light based on detection invisible light
Data Source
AI summary
A projection display unit includes a projection optical system, a polarization separation device, and a detection optical system. The projection optical system includes an illuminator, a projection lens, and a light valve that modulates illumination light supplied from the illuminator, and outputs the modulated illumination light toward the projection lens. The polarization separation device separates entering light into a first polarized component and a second polarized component, and outputs the first polarized component and the second polarized component in respective directions that are different from each other. The detection optical system includes an imaging device and a reduction optical system. The imaging device receives, via the projection lens and the polarization separation device, light based on detection invisible light. A transmittance adjuster provided between the polarization separation device and the imaging device adjusts transmittance of at least part of a bundle of passing light rays derived from the invisible light.