Liquid Crystal Display Touch Sensing via Infrared Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices with integrated touch panels face challenges in accurately sensing touch inputs due to variations in external and reflected light conditions, leading to inconsistent touch sensitivity and increased production costs, thickness, and complexity in algorithms for position detection.
Innovation Solution
Incorporating an infrared sensor and filter within the liquid crystal display device, along with a light guiding plate and separate infrared light sources, to sense infrared light reflected upon touch, thereby isolating touch signals from external light and enhancing sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a touch screen panel is adhered onto the liquid crystal display device to enable touch sensing, then touch sensing capability is improved, but production costs increase, yield decreases, and device thickness increases
Solution Approach 1:
The patent merges the touch sensing function with the liquid crystal display panel by integrating the infrared sensor and infrared filter directly into the display panel structure. The infrared sensor is formed in a non-display region of the liquid crystal panel, and the infrared filter is integrated into the color filter layer, eliminating the need for a separate touch screen panel and reducing production complexity
Solution Approach 2:
The liquid crystal display panel is designed to serve multiple functions: displaying visual information and sensing touch inputs. The infrared sensor and infrared filter are incorporated into the display panel structure, enabling the same device to perform both display and touch sensing functions without requiring separate components
2Adaptability or versatility
If photosensors are adhered onto the external surface of the display panel to sense touch, then touch sensing is enabled, but the volume of the display device increases
Solution Approach 1:
The touch sensing components (infrared sensor and infrared filter) are nested within the existing liquid crystal display panel structure. The infrared filter is integrated into the color filter layer, and the infrared sensor is formed in a non-display region, allowing the touch sensing function to be embedded within the display device without increasing its external volume
3Adaptability or versatility
If a touch screen panel is adhered onto the liquid crystal display device, then touch sensing is enabled, but the luminance of the liquid crystal panel deteriorates
Solution Approach 1:
The infrared filter acts as an intermediary that selectively transmits infrared light while blocking visible light. This allows the infrared sensor to detect touch inputs through the color filter layer without interfering with the visible light transmission and luminance performance of the liquid crystal display panel
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 enables stable and accurate touch sensing regardless of external light conditions, reducing device thickness and production costs while improving touch sensitivity and reducing errors.
Implementation Method 1
an infrared sensor arranged on the first substrate, an infrared filter arranged corresponding to the infrared sensor arranged on the second substrate facing the first substrate
Implementation Method 2
sense infrared light reflected upon touch
Implementation Method 3
a light guiding plate arranged under the first substrate
Data Source
AI summary
Disclosed is a liquid crystal display device to realize soft touch and sense touch regardless of illumination of external light or reflected light. The liquid crystal display device includes a liquid crystal panel including a first substrate and a second substrate facing each other, wherein a liquid crystal layer is interposed between the first substrate and the second substrate, an infrared sensor arranged on the first substrate, an infrared filter arranged corresponding to the infrared sensor arranged on the second substrate facing the first substrate, a first polarizing plate adhered to the back surface of the first substrate, a second polarizing plate adhered to the back surface of the second substrate, a light guiding plate arranged under the first polarizing plate, a first light source arranged on one side of the light guiding plate to emit white light, and a second light source arranged on the other side of the light guiding plate to emit infrared light to the light guiding plate.