Transparent Image Projection Screen with Surface Irregularities
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Solution Overview
Problem
Existing image projecting structures face challenges in providing high visibility of both projected images and background views, especially with limited viewing angles, which restricts their application in environments requiring wide-angle visibility like windows in rooms.
Innovation Solution
The structure comprises a transparent substrate with a first transparent layer having fine irregularities, a reflective film, and a second transparent layer, where the irregularities on the first layer are designed to provide a wide viewing angle by controlling the transmittance and diffuse reflectance, ensuring high visibility of both the projected image and background.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transmitting type screen is used to display images from the rear side, then light transmission is improved, but the ability to observe the rear side view is lost
Solution Approach 1:
The screen is designed to perform multiple functions: it can display projected images from the rear side while simultaneously allowing observers to see through it to the rear side view, making it adaptable for both image display and transparent window applications
Solution Approach 2:
The screen employs a composite structure with a transparent substrate, irregularities layer, metal film layer, and transparent material layer, combining different materials to achieve both light transmission and rear side visibility functions
2Adaptability or versatility
If a reflective screen with irregularities and metal film is used to observe rear side images, then rear side visibility is improved, but image brightness and visibility are insufficient
Solution Approach 1:
The invention optimizes parameters including the refractive index of the transparent material (1.3-1.6), the thickness of the metal film (5-50 nm), and the characteristics of surface irregularities to achieve optimal balance between image brightness and rear side visibility
Solution Approach 2:
Different layers of the screen structure have specialized functions: the irregularities layer controls light scattering for viewing angle, the metal film layer provides reflectance for image brightness, and the transparent material layer fills irregularities while maintaining optical properties
3Illumination intensity
If regular reflection is used for image projection, then visibility at the reflection position is high, but visibility at the end portions and for multiple observers is limited
Solution Approach 1:
The screen introduces surface irregularities with curved profiles rather than flat surfaces, causing light to reflect in multiple directions rather than a single regular reflection path, thereby expanding the viewing angle for multiple observers
Solution Approach 2:
The invention transitions from one-dimensional regular reflection to three-dimensional diffuse reflection by adding surface irregularities, enabling light to reach observers at various positions and angles simultaneously
4Area of stationary object
If the screen size is increased to cover larger areas, then coverage is improved, but the reflection angle becomes smaller and visibility for observers decreases
Solution Approach 1:
Surface irregularities with curved profiles scatter light in multiple directions, compensating for the reduced reflection angle effect in large-sized screens and maintaining visibility for observers across the entire screen area
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 enhances the visibility of the projected image and background views across a wide range of angles, making it suitable for applications where both image projection and transparent window functionality are needed.
Implementation Method 1
a first transparent layer (21) formed on the transparent substrate (10) and having fine irregularities
Implementation Method 2
a reflective film (30) formed on the surface on which the irregularities are formed, of the first transparent layer (21)
Implementation Method 3
a second transparent layer (22) formed on the reflective film (30)
Data Source
Figure 1~4
Figure 5(A)~6(D)
Figure 7(A)~7(C)
AI summary
To provide an image projecting structure having a wide viewing angle and whereby the visibility of a projected image is high. The image projecting structure comprises a first transparent layer having irregularities formed on its surface, a reflective film formed on the surface on which the irregularities are formed, of the first transparent layer, and a second transparent layer formed on the reflective film, wherein the transmittance of visible light is from 5 to 95%; the value obtained by dividing the haze by the diffuse reflectance of visible light is at least 0.1 and at most 1; the vertical difference Sk in the core section defined by ISO 25178, of the surface on which the irregularities are formed, is at least 0.1 µm; and the value obtained by dividing the shortest autocorrelation length Sal by the vertical difference Sk in the core section is at least 1.2 and at most 190.