Filter Device Segmentation for Stable Projection Illumination
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Solution Overview
Problem
Current projection devices experience brightness loss due to unstable mixed color light incident on the light valve, caused by the phosphor color wheel's rapid rotation, leading to light spots irradiating different regions simultaneously, resulting in mixed color light and a turn-off state of the micro lens array.
Innovation Solution
An illumination system comprising a blue light source, a red light source, a wavelength conversion device, a first light splitting element, a filter device, and a light uniformizing element, where the blue excitation light beam is converted into an excited light beam, and the red light beam passes through different regions of the filter device in varying time intervals, preventing unstable mixed color light from reaching the light valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a phosphor color wheel is used to convert blue laser light to yellow-green light and a color filter wheel to filter red/green light, then three primary colors (RGB) can be produced for projection, but unstable mixed color light is generated when the light spot irradiates junctions of different regions during rapid rotation, causing the light valve to enter turn-off state and resulting in brightness loss
Solution Approach 1:
The filter device is divided into multiple independent filter regions (first filter region, second filter region, third filter region) with different spectral transmission characteristics. Each region filters specific wavelength bands independently, allowing precise control over which colors reach the light valve at any given time during the rotation cycle, thereby eliminating unstable mixed color light while maintaining color generation capability
Solution Approach 2:
Different regions of the filter device are assigned different optical properties - the first filter region transmits blue light while blocking red and green, the second filter region transmits red light while blocking blue and green, and the third filter region transmits green light while blocking blue and red. This local differentiation ensures that only stable, single-color light reaches the light valve during each time interval, preventing brightness loss
2Reliability
If the phosphor color wheel rotates rapidly to produce colors, then color saturation can be achieved, but the light spot simultaneously irradiates junctions of different regions, generating mixed color light that destabilizes the illumination
Solution Approach 1:
The filter device is segmented into distinct filter regions, each responsible for transmitting a specific color band. This segmentation ensures that during rapid rotation, the light spot passes through well-defined regions rather than ambiguous junctions, maintaining consistent color output and preventing mixed color light generation at region boundaries
Solution Approach 2:
The filter device acts as an intermediary between the broadband light source and the light valve, selectively transmitting only the desired wavelength bands while blocking others. This intermediary function stabilizes the light color by ensuring that only pure spectral bands reach the light valve, eliminating color inconsistency caused by junction irradiation
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 ensures stable light input to the light valve, enhancing the projection brightness by avoiding the turn-off state and improving the usage efficiency of the light valve.
Implementation Method 1
The wavelength conversion device is disposed on a transmission path of the blue excitation light beam for converting the blue excitation light beam into an excited light beam
Implementation Method 2
The first light splitting element is disposed on a transmission path of the blue excitation light beam and the excited light beam, and is configured to allow one of the blue excitation light beam and the excited light beam to pass through and reflect the other
Implementation Method 3
The filter device is disposed on a transmission path of the red light beam, the blue excitation light beam and the excited light beam and includes a filter region
Data Source
AI summary
An illumination system and a projection device using the same are provided. The illumination system provides an illumination light beam and includes a blue light source, a red light source, a wavelength conversion device, a first light splitting element, a filter device, and a light uniformizing element. The blue light source provides a blue excitation light beam. The red light source provides a red light beam. The wavelength conversion device converts the blue excitation light beam into an excited light beam. The filter device includes a filter region. The blue excitation light beam, the excited light beam and the red light beam are sequentially transmitted to the filter device and the light uniformizing element to form the illumination light beam, wherein the excited light beam and the red light beam pass through the filter region in different time interval.