Edge-Lit Display Light Guide Segmentation for Luminance Uniformity
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Solution Overview
Problem
Display apparatuses with edge-light-type light source devices face challenges in maintaining high image quality and preventing image deterioration due to light intensity variations across different areas of the light guide member, leading to uneven luminance and potential defocused moving images.
Innovation Solution
A display apparatus with a light source device featuring a light guide member divided into areas with light modulation layers that can switch between transmission and scattering states, controlled by a device that applies electric fields to manage light emission based on distance from the light source, ensuring consistent light intensity across areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the light guide member uses a single light source at the edge, then the device structure is simple and power consumption is low, but the light intensity becomes uneven across different areas causing image quality deterioration
Solution Approach 1:
The light guide member is divided into multiple areas with different light modulation layers (first, second, and third light modulation layers) positioned at different distances from the light source. Each area can independently control light scattering, allowing differential light intensity management across the display surface while using a single edge-mounted light source.
Solution Approach 2:
Different light modulation layers are applied to different areas of the light guide member based on their distance from the light source. Areas closer to the light source use light modulation layers with different scattering properties than areas farther away, creating local quality variations that compensate for the natural light intensity gradient and achieve uniform overall illumination.
2Illumination intensity
If the light modulation layer is always in scattering state, then the light intensity is increased, but the power consumption increases and image quality deteriorates due to defocused moving images
Solution Approach 1:
The light modulation layers are controlled to switch between transmission and scattering states in a time-division manner. During specific display periods, certain areas scatter light to enhance brightness, while during other periods, they transmit light to reduce power consumption. This periodic switching allows the system to achieve high light intensity when needed while minimizing overall power consumption.
Solution Approach 2:
The light modulation layers are designed to dynamically change their optical state between transmission and scattering based on display requirements. This dynamic control allows the system to adapt light intensity in real-time without maintaining continuous high-power operation, thereby reducing overall power consumption while preventing image deterioration.
3Illumination intensity
If multiple light sources are used to improve light intensity uniformity, then the light intensity uniformity is improved, but the device complexity and power consumption increase
Solution Approach 1:
Instead of using multiple physical light sources, the system segments the light guide member into multiple areas with different light modulation layers. Each segment can independently modulate light scattering to compensate for position-dependent intensity variations, achieving uniform illumination without adding multiple light source components.
Solution Approach 2:
Light modulation layers serve as intermediary elements between the single light source and the display surface. These layers actively modulate the light path and scattering properties to achieve uniform light distribution, replacing the need for multiple light sources and simplifying the overall device structure.
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 maintains consistent light intensity across the display surface, preventing image deterioration and ensuring high-quality image display by adjusting the scattering state and electric field application periods based on the distance from the light source.
Implementation Method 1
a light modulation layer brought in a transmission state in which the light is transmitted through the light modulation layer or in a scattering state in which the light is scattered in the light modulation layer
Implementation Method 2
a control device that brings the light modulation layers of the areas in the scattering state in respective scattering control periods
Data Source
AI summary
A display apparatus includes an image display panel, a light source device, and a control device. The light source device includes a light source that emits light and a light guide member arranged on the back surface side of the panel as seen from the display surface, receives the light via its side surface with respect to its surface facing the panel, and has divided areas arranged in a direction in which the light travels. Each area includes a light modulation layer brought in a light transmission state or in a light scattering state. The control device brings the layers in the scattering state in respective scattering control periods temporally different from each other. When bringing a light modulation layer in the scattering state, the control device controls the light source device with a drive pattern based on a distance between the side surface and the corresponding area.