Translucent Screen with Switchable Light Control Films
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Solution Overview
Problem
Existing image projection systems face challenges in maintaining high contrast and usability in bright environments due to external light interference, particularly when using translucent screens for displaying projected images.
Innovation Solution
The system incorporates a translucent screen with a first light control film switchable between transmissive and diffusion states and a second light control film with adjustable transmittance, controlled by a controller to optimize image projection modes, including a transparent mode, image projection mode, and light blocking mode, reducing external light reflection and enhancing contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a translucent screen is used for image projection, then the screen allows light transmission and can be viewed from both sides, but external light reflection reduces image contrast in bright environments
Solution Approach 1:
The patent applies a light control film that can dynamically switch between different states (transmissive, reflective, and intermediate states) based on the projection mode. This dynamic adjustment allows the screen to adapt to different lighting conditions and projection requirements, resolving the contradiction between maintaining light transmission capability and reducing external light reflection that harms image contrast.
Solution Approach 2:
The light control film changes its optical parameters (transmittance and reflectance) by applying or removing voltage. In transmission mode, the film has high transmittance for viewing from both sides; in projection mode, it switches to high reflectance to enhance image contrast by reducing external light reflection. This parameter change resolves the contradiction between the two opposing requirements.
2Illumination intensity
If the screen transmittance is increased for better visibility in bright environments, then external light interference increases, but image contrast deteriorates
Solution Approach 1:
The light control film provides dynamic control over transmittance, allowing the system to adjust the balance between screen visibility and external light interference based on projection mode. This resolves the contradiction by making transmittance adjustable rather than fixed.
Solution Approach 2:
The patent changes the optical parameter of transmittance by applying voltage to the light control film. In projection mode, transmittance is reduced to minimize external light interference; in viewing mode, transmittance is increased for better visibility. This parameter change directly resolves the contradiction between illumination intensity and external light interference.
3Object-affected harmful factors
If the screen is set to block external light for high contrast projection, then image contrast improves, but the screen loses transparency and cannot be viewed from both sides
Solution Approach 1:
The light control film dynamically switches between reflective state (for high contrast projection) and transmissive state (for bidirectional viewing). This dynamic switching allows the screen to alternate between the two opposing functions based on projection mode, resolving the contradiction.
Solution Approach 2:
The patent changes the reflectance parameter of the light control film by applying voltage. In projection mode, reflectance is increased to block external light and improve contrast; in viewing mode, reflectance is decreased to maintain transparency and bidirectional viewing capability. This parameter change resolves the contradiction between external light interference and adaptability.
4Device complexity
If a single light control film is used, then the structure is simple, but the screen cannot simultaneously achieve high contrast projection and bidirectional viewing
Solution Approach 1:
The single light control film performs multiple functions by switching between different states. It provides both high contrast projection (by reflecting projection light) and bidirectional viewing (by transmitting ambient light) capabilities within one component, eliminating the need for separate structures for each function while maintaining adaptability.
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 effectively increases the contrast of projected images by managing transmittance and diffusion states, allowing for high-contrast image display even in bright environments and improving user usability by automatically adjusting the screen's mode based on image projection status.
Implementation Method 1
a first light control film configured to be switchable between a transmissive state for transmitting incident light therethrough and a diffusion state for diffusing incident light
Implementation Method 2
a second light control film configured such that the transmittance thereof with respect to incident light is changed
Data Source
AI summary
An image projection system includes a translucent screen, a projector that projects image light to the translucent screen, and a controller that controls the projector and the translucent screen. The translucent screen includes a first light control film configured to be switchable between a transmissive state for transmitting incident light therethrough and a diffusion state for diffusing incident light, and a second light control film configured such that the transmittance thereof with respect to incident light can be changed. The controller has: a first mode in which, in the state where the projector does not project image light, the first light control film is in the transmissive state and the second light control film is in the state of having transmittance for transmitting incident light therethrough; and a second mode in which, in the state where the projector projects image light, the first light control film is in the diffusion state and the second light control film is in the state of having transmittance lower than the transmittance in the first mode. The controller is settable to the first mode or the second mode.