Variable Light Scattering Glazing with Mirror Layer for Projection
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Solution Overview
Problem
Existing projection screens with variable light scattering systems suffer from low luminance, contrast, and limited angle of view, especially when used as projection screens in reflection mode, and are not suitable for various lighting environments.
Innovation Solution
A glazing with a variable light scattering system and a mirror layer, capable of switching between a mirror state and a scattering state, featuring low light transmission and high light reflection, allowing for improved luminance, contrast, and angle of view, while preventing image visibility through the opposite face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switchable glazing comprising liquid crystals is used as projection screen, then the glazing can switch between transparent and scattering states, but the luminance and contrast of the projected image are weakened due to low diffuse reflection and high light transmission
Solution Approach 1:
The patent combines a variable light scattering system (liquid crystal film) with a semireflecting layer to create a composite glazing structure. This composite structure integrates the switching capability of liquid crystals with the light reflection properties of the semireflecting layer, achieving both adaptability and improved luminance/contr a st for projection screens
Solution Approach 2:
The patent modifies the optical parameters of the glazing by introducing a semireflecting layer with specific reflection and transmission characteristics. This changes the light interaction properties from primarily transmission-based to a balanced combination of reflection and transmission, improving projection quality while maintaining switching functionality
2Illumination intensity
If the light transmission of the glazing is high, then the glazing maintains good transparency in transparent state, but the luminance of the projected image strongly decreases when the angle of observation increases
Solution Approach 1:
The patent adjusts the optical parameters by selecting a semireflecting layer with specific reflection (R) and transmission (T) values where R>T. This parameter adjustment creates a balance between maintaining transparency when needed and providing sufficient diffuse reflection for projection viewing at various angles
3Ease of operation
If the glazing is used in the scattering state for projection, then direct projection is possible, but the quality of image projection is mediocre with low luminance, low contrast, and low angle of view
Solution Approach 1:
The patent creates a composite structure combining the variable light scattering system with a semireflecting layer. This composite enables direct projection in scattering state while significantly improving luminance, contrast, and viewing angle compared to using the liquid crystal film alone
Solution Approach 2:
The semireflecting layer acts as an intermediary between the projector and the liquid crystal film, mediating the light path to enhance diffuse reflection and improve projection quality without interfering with the switching functionality of the liquid crystal system
4Adaptability or versatility
If the glazing combines variable light transmission/absorption system and variable light scattering system, then the glazing can function as back-projection or projection screen, but image projection in reflection still suffers from low luminance, low contrast, and low angle of view
Solution Approach 1:
The patent optimizes the optical parameters by selecting a semireflecting layer where reflection R is greater than transmission T. This parameter change distinguishes the invention from prior art and enables satisfactory reflection projection quality while maintaining multi-functionality
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
The solution enhances the quality of projected images by increasing luminance and contrast, and expanding the angle of view, while maintaining the mirror functionality and confidentiality of the projected image, regardless of the lighting environment.
Implementation Method 1
a variable light scattering system comprising a functional film capable of switching between a transparent state and a scattering state
Implementation Method 2
a coating comprising at least one mirror layer... exhibiting a light transmission LT of less than 20%, a light reflection LR of more than 25%
Data Source
AI summary
The invention relates to a glazing used as projection screen operating in reflection, comprising a front face, onto which the image is projected, and a rear face. The glazing comprises a variable light scattering system comprising a functional film capable of switching between a transparent state and a scattering state and a coating comprising at least one mirror layer, said coating being separated from the front face at least by the functional film.The invention also relates to the use of a glazing as projection screen, to a projection system and to a projection method using said glazing.