Adjustable Viewing Angle Display Device with Voltage-Controlled Diffusion
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Solution Overview
Problem
Conventional anti-peep mechanisms for display devices compromise display quality, optical properties, thickness, and weight to achieve privacy, and fail to effectively reduce light leakage in narrow viewing angle mode.
Innovation Solution
An adjustable viewing angle display device with a pixel array and electrodes on substrates, where the potential difference between electrodes is controlled to minimize light leakage in the narrow viewing angle mode without increasing cost or complexity, using a non-self-luminous display medium layer and electrode configurations that allow for optimal potential differences to reduce light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional anti-peep sheet is installed on the display panel, then privacy protection is achieved, but display quality and optical properties are degraded
Solution Approach 1:
The patent combines the anti-peep function with the display panel itself by integrating a voltage-controlled diffusion sheet into the backlight assembly, rather than installing a separate anti-peep sheet on the display panel. This merging approach eliminates the need for additional optical films that would degrade display quality, while achieving privacy protection through controlled light diffusion.
Solution Approach 2:
The patent introduces a voltage-controlled diffusion sheet as an intermediary component in the backlight assembly. This diffusion sheet acts as a mediator that controls light distribution - when voltage is applied, it maintains collimated light for normal viewing; when voltage is removed, it diffuses light to prevent peeping. This intermediary approach achieves privacy protection without directly affecting the display panel's optical properties.
2Ease of operation
If a voltage-controlled diffusion sheet is used in the backlight source, then switching between wide and narrow viewing angle modes is convenient, but light leakage cannot be reduced to an unidentifiable level
Solution Approach 1:
The patent applies a specific voltage range (0.04V to 1.04V) between the first and second electrodes to precisely control the liquid crystal molecules' orientation. By changing the electrical parameter (voltage) within this specific range, the liquid crystal layer transitions to a state that effectively blocks side-view light leakage while maintaining normal display function, achieving unidentifiable light leakage levels.
Solution Approach 2:
The patent uses a composite structure combining a liquid crystal layer with the backlight assembly. The liquid crystal layer, when subjected to specific voltage, changes its optical properties to block light leakage. This composite approach integrates the light-blocking function into the existing backlight system, achieving effective light leakage reduction while maintaining ease of operation through voltage control.
3Reliability
If a viewing angle control module is added to the display panel, then image quality is preserved in wide viewing angle mode, but device weight and thickness increase significantly
Solution Approach 1:
The patent merges the viewing angle control function with the existing backlight assembly by integrating a voltage-controlled diffusion sheet and liquid crystal layer into the backlight structure. This eliminates the need for a separate viewing angle control module, thereby preserving image quality without increasing device weight and thickness.
Solution Approach 2:
The patent makes the backlight assembly multi-functional by enabling it to perform both illumination and viewing angle control functions. The voltage-controlled diffusion sheet and liquid crystal layer in the backlight assembly provide viewing angle adjustment capabilities, eliminating the need for additional dedicated modules and reducing overall device weight.
4Object-affected harmful factors
If a viewing angle control module is added to the display panel, then narrow viewing angle mode is achieved, but manufacturing cost increases
Solution Approach 1:
The patent combines the viewing angle control function with the existing backlight assembly components, eliminating the need for a separate viewing angle control module. This integration approach reduces part count and assembly complexity, thereby lowering manufacturing costs while achieving effective side view brightness reduction.
Solution Approach 2:
The backlight assembly serves itself by incorporating the viewing angle control functionality directly into its structure. The voltage-controlled diffusion sheet and liquid crystal layer within the backlight assembly provide the viewing angle adjustment capability, eliminating the need for additional dedicated components and reducing overall manufacturing cost.
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 effectively reduces light leakage in the dark state, enhancing contrast in the narrow viewing angle mode without increasing costs or complexity, while maintaining display quality and optical properties.
Implementation Method 1
A backlight source that emits light with high collimation is utilized. The backlight source is equipped with a voltage-controlled diffusion sheet, for example a polymer-dispersed liquid crystal (PDLC) film. When the voltage applied to the diffusion sheet is turned off, the voltage-controlled diffusion sheet diffuses the collimated light and a portion of light is directed towards the side view, so that a wide viewing angle mode is realized. When the voltage applied to the diffusion sheet is turned on, the voltage-controlled diffusion sheet does not cause diffusion of the original collimated radiation, so that a narrow viewing angle mode is achieved.
Data Source
AI summary
Disclosed herein is an adjustable viewing angle display device. The display device includes a display panel composed of a first substrate, a second substrate, a display medium layer interposed therebetween, a first electrode, a second electrode and a third electrode. Pluralities of sub-pixels are defined in the display panel. The first and second electrodes are disposed on the first substrate in the sub-pixels. The first electrode is spaced apart from the second electrode. The third electrode is disposed on the second substrate. When the display device is operated in a narrow viewing angle mode, there exists a non-zero potential difference between the second electrode and the third electrode, and when the sub-pixel is at gray level of zero, the potential difference between the first electrode and the second electrode is not zero. A driving method for driving the display device is disclosed as well.