Angle Distribution Conversion Sheet for Display Position Detection
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Solution Overview
Problem
Existing display devices face challenges in accurately reading position information patterns, especially when the electronic pen is tilted, due to reduced transmittance of light through prism sheets, leading to decreased contrast and difficulty in detecting position coordinates.
Innovation Solution
Incorporating an angle distribution conversion sheet between the prism sheets and the display panel, which alters the angle distribution of light incident on the display surface, ensuring that 20% or more of the light passes through specific conversion regions, thereby increasing transmittance and maintaining accurate position coordinate detection even when the pen is tilted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a prism sheet is used to provide directivity to light from the surface light source section, then light emission directivity is improved, but transmittance of light incident at angles between 40° and 60° deteriorates
Solution Approach 1:
An angle distribution conversion sheet is introduced as an intermediary component between the light source and the prism sheet. This conversion sheet modifies the angular distribution of light before it reaches the prism sheet, ensuring that light arrives at the prism sheet at optimal angles for high transmittance while still achieving the desired directivity in the final emitted light.
Solution Approach 2:
The patent changes the angular distribution parameter of incident light by using the angle distribution conversion sheet. By controlling the incident angle distribution, the system ensures that light passes through the prism sheet at angles where transmittance is maximized, thereby resolving the contradiction between directivity and transmittance.
2Illumination intensity
If the transmittance of the prism sheet is low for light incident at angles between 40° and 60°, then position information pattern reading accuracy deteriorates, but light directivity is maintained
Solution Approach 1:
The angle distribution conversion sheet serves as a mediator that transforms the angular distribution of light before it reaches the prism sheet. This ensures that light intended for reading position information patterns arrives at the prism sheet at angles with high transmittance, thereby maintaining both directivity and reading accuracy.
Solution Approach 2:
The angle distribution conversion sheet performs preliminary action by pre-adjusting the angular distribution of light before it encounters the prism sheet. This preliminary adjustment ensures that light is oriented at optimal angles for both high transmittance and accurate position information pattern reading.
3Measurement precision
If an angle distribution conversion sheet is added to improve light transmittance and reading accuracy, then position information detection accuracy is improved, but device complexity increases
Solution Approach 1:
The angle distribution conversion sheet is implemented as a thin film component that can be integrated into the existing backlight unit structure. This minimizes the increase in device complexity while achieving the desired improvement in light transmittance and position information detection accuracy.
Solution Approach 2:
The angle distribution conversion sheet performs multiple functions: it adjusts angular distribution to improve transmittance through the prism sheet, maintains light directivity, and enhances position information pattern reading accuracy. By consolidating these functions into a single component, the increase in device complexity is minimized.
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 accuracy of position information reading by maintaining high contrast images of position information patterns, allowing for precise detection of coordinates regardless of pen inclination.
Implementation Method 1
at least one prism sheet configured to cause light emitted from the surface light source section to have directivity
Implementation Method 2
The angle distribution conversion sheet has a conversion region that causes light incident on a front surface thereof at the determined angle as an incident angle with respect to a sheet surface of the angle distribution conversion sheet to be emitted from a back surface thereof at an emission angle of not larger than 40° or not smaller than 60°
Data Source
AI summary
The display device includes: a display panel; and a surface light source section. A transmittance of light transmitted from a front surface of a prism sheet of the surface light source section is lowest when an incident angle thereof is a determined angle. An angle distribution conversion sheet of the surface light source section has a conversion region that causes light incident on a front surface thereof at the determined incident angle to be emitted from a back surface thereof at an emission angle of not larger than 40° or not smaller than 60°, in a cross-sectional view in a direction perpendicular to an extension direction of prisms. When light is applied to the front surface of the angle distribution conversion sheet at the determined incident angle and in the direction in a front view, 20% or more of the light passes through the conversion region.