Projector Polarizer Segments Infrared Detection from Visible Image Projection
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Solution Overview
Problem
Existing projectors that project images and detect pointing elements using infrared light face challenges in ensuring a sufficient period for infrared light radiation due to time division methods, which can result in inadequate detection of pointing elements.
Innovation Solution
A projector design that incorporates an illumination system outputting visible and infrared light, an image formation section using liquid crystal display devices and polarizers to adjust polarization, and a detection section that utilizes reflected infrared light for pointing element detection, allowing for simultaneous image projection and infrared light radiation with sufficient intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If time division method is used for image projection and infrared light radiation, then the projector can integrate both functions in a compact design, but the infrared light radiation period becomes insufficient for reliable pointing element detection
Solution Approach 1:
The patent segments the light path into separate visible light and infrared light channels. The visible light passes through the liquid crystal display device for image projection, while the infrared light bypasses the liquid crystal display device and goes directly through the polarizer and projection lens. This segmentation allows both functions to operate simultaneously without time division, resolving the contradiction between compact integration and sufficient infrared radiation duration.
2Adaptability or versatility
If time division method is used for projecting red, green, and blue light, then the projector can form color images, but the infrared light radiation amount becomes insufficient for detection
Solution Approach 1:
The patent separates the color projection path (visible light through liquid crystal display) from the infrared detection path (infrared light bypassing liquid crystal display). This allows color images to be projected while maintaining sufficient infrared light radiation amount for detection, resolving the contradiction between color image capability and infrared light quantity.
Solution Approach 2:
The patent introduces a polarizer as an intermediary element that selectively transmits infrared light while allowing visible light to pass through the liquid crystal display device. The polarizer acts as a mediator that enables both color projection and infrared radiation to coexist without interference, ensuring sufficient infrared light reaches the projection surface for reliable detection.
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
Enables effective detection of pointing elements with a uniform and sufficient infrared light radiation, improving the projector's ability to detect user inputs while maintaining image projection quality.
Implementation Method 1
a liquid crystal display device that adjusts a polarization direction of the illumination light on a pixel basis
Implementation Method 2
a first polarizer that is disposed on a light exiting side of the liquid crystal display device and transmits the illumination light outputted from the liquid crystal display device in accordance with the polarization direction of the outputted illumination light
Implementation Method 3
the first polarizer transmits the infrared light in such a way that the first polarizer transmits the first and second polarization components of the infrared light
Implementation Method 4
a detection section that detects a pointing element with which an instruction is issued on the projection surface based on reflected light formed of the radiated infrared light
Data Source
AI summary
A projector includes an illumination system that outputs illumination light containing white light, which is visible light, and infrared light, an image formation section that forms image light from the illumination light, a projection system that projects the image light on a projection surface and radiates the infrared light onto the projection surface, and a detection section that detects a pointing element based on reflected light formed of the radiated infrared light. The image formation section includes a light-exiting-side polarizer that transmits the visible light in such a way that the light-exiting-side polarizer transmits light formed of one polarization component and blocks light formed of another polarization component, and the light-exiting-side polarizer transmits the infrared light in such a way that the light-exiting-side polarizer transmits the two polarization components of the infrared light.