View Angle Control Sheet with Trapezoidal Lens and Wedge Structure
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Solution Overview
Problem
Conventional louver type view angle control sheets block screen image light in oblique directions, leading to reduced screen brightness and contrast due to outside light interference, while failing to prevent ghost image generation.
Innovation Solution
A view angle control sheet with trapezoidal lens portions and wedge-shaped sections, where the wedge-shaped portions have a refractive index lower than the lens portions, are arranged to control light angles between 3 to 15 degrees, utilizing diffuse light effectively and incorporating light-absorbing particles to suppress brightness decrease and ghost generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a louver type view angle control sheet is used to block outside light beams, then contrast is enhanced, but screen brightness decreases due to blocking of screen image light in oblique directions
Solution Approach 1:
The patent changes the geometric parameters of the view angle control sheet by using trapezoidal lens portions with specific width ratios and wedge-shaped portions with controlled angles (θ between 3-15 degrees). This parameter optimization allows the structure to selectively block oblique outside light while transmitting more direct screen image light, thereby improving contrast without excessive brightness loss
Solution Approach 2:
The patent employs composite material structure combining lens portions made of one material with wedge-shaped portions filled with different materials (having different refractive indices). This composite approach enables precise control of light transmission and reflection characteristics, allowing the sheet to differentiate between screen image light and outside light paths, thus enhancing contrast while maintaining brightness
2Ease of operation
If a louver type view angle control sheet blocks oblique light, then view angle control is improved, but ghost images are generated
Solution Approach 1:
The patent applies local quality by creating distinct regions with different optical properties: trapezoidal lens portions for primary light control and wedge-shaped portions with specific angle ranges (3-15 degrees) for secondary control. This localized structural differentiation enables precise control of light paths to prevent ghost image formation while maintaining view angle control
Solution Approach 2:
The patent converts the potentially harmful effect of light reflection that causes ghost images into a beneficial control mechanism. By carefully designing the wedge-shaped portions with specific angles, the structure redirects reflected light away from the observer's line of sight, transforming what would be ghost-causing reflections into controlled light paths that enhance the primary image
3Object-generated harmful factors
If the wedge-shaped portion angle θ is less than 3 degrees, then ghost prevention is improved, but brightness improvement effect is lost because diffuse light does not reach the observer
Solution Approach 1:
The patent identifies and optimizes the critical parameter θ (angle of the wedge-shaped portion) by establishing the optimal range of 3-15 degrees. This parameter optimization ensures that diffuse light from the screen is properly redirected to reach the observer while maintaining sufficient angle to prevent ghost image formation, thus simultaneously achieving both brightness improvement and ghost prevention
4Illumination intensity
If the wedge-shaped portion angle θ exceeds 15 degrees, then brightness improvement is enhanced, but ghost images are generated
Solution Approach 1:
The patent establishes the upper bound of the angle parameter θ at 15 degrees through optimization. This parameter constraint ensures that while sufficient brightness improvement is achieved by redirecting diffuse light to the observer, the angle remains small enough to prevent the formation of ghost images by controlling reflected light paths
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 screen brightness and contrast by effectively utilizing diffuse light, preventing ghost images, and improving the view angle control, resulting in a high-quality view angle control sheet with improved optical characteristics.
Implementation Method 1
the wedge-shaped portion has a refractive index lower than the lens portions, are arranged to control light angles between 3 to 15 degrees
Implementation Method 2
incorporating light-absorbing particles to suppress brightness decrease and ghost generation
Data Source
AI summary
A view angle control sheet having a wide view angle, in which diffuse light from a screen image source is effectively utilized to suppress a decrease in screen brightness while a decrease in image contrast caused by an outside light beam is suppressed to prevent generation of a ghost to improve contrast. The lens portions have trapezoidal shapes in section arranged at predetermined intervals. A wedge-shaped portion between the lens portions has a bottom surface on a screen image source side while having a leading end on an observer side, and the following relationships hold: Nx £ Ny and −0.01<Dn−cos q<0.002, where Nx is a refractive index of a material constituting at least a slope portion of the wedge-shaped portion, Ny is a refractive index of a material constituting the lens portion, and Dn is a ratio (Nx/Ny).