Light-Transmissive Input Device Shielding Layers
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Solution Overview
Problem
Existing light-transmissive input devices face challenges in effectively blocking display light from the rear while maintaining a thin structure, and in preventing erroneous electrostatic capacitance formation between fingers and wiring patterns, which leads to reduced transmittance and increased complexity or weight.
Innovation Solution
The device employs non-light-transmissive conductive shielding layers formed from the same material as the wiring patterns, which vertically overlap the wiring patterns on both surfaces, functioning as effective shields without the need for additional insulating layers, thus enhancing light blocking and reducing the risk of erroneous detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a thick decorative printing layer is formed by alternately overlapping white printing layer and decorative color printing layer to block light from display device, then light-blocking function is improved, but air gap is more likely to be formed between base material and adhesive layer, causing light reflection and reduced transmittance
Solution Approach 1:
The patent combines the decorative function and light-blocking function into a single decorative layer. The decorative layer is formed by printing a decorative pattern on a light-transmissive base material, where the decorative pattern itself provides the light-blocking effect without requiring multiple overlapping layers. This eliminates the air gap problem while maintaining both aesthetics and light-blocking performance.
Solution Approach 2:
The patent applies local quality by making only the necessary portions of the decorative layer opaque for light-blocking purposes. The decorative pattern is designed to block light only in specific areas where wiring patterns are located, while other areas remain light-transmissive. This allows the decorative layer to be thin overall while still providing effective light-blocking where needed.
2Reliability
If wiring pattern is exposed in the periphery of detection area, then electrostatic capacitance is easily formed between finger and wiring pattern causing erroneous detection, but adding shielding layer increases device complexity
Solution Approach 1:
The patent merges the shielding function with the decorative layer. The decorative layer serves dual purposes: providing aesthetic appearance and acting as an electrostatic shield. By forming the decorative layer as a continuous conductive layer that covers the wiring patterns in the peripheral area, the patent eliminates erroneous detection without adding separate shielding layers or insulating layers, thus maintaining simple device structure.
Solution Approach 2:
The decorative layer is designed to perform multiple functions simultaneously: (1) providing decorative appearance, (2) blocking light from the display device, and (3) serving as an electrostatic shield. This multi-functionality eliminates the need for separate components and reduces overall device complexity while improving reliability.
3Ease of manufacture
If shielding layer is formed of same ITO transparent conductive film as electrode pattern, then manufacturing is simplified, but shielding layer remains in wide range requiring insulating layer and increasing thickness
Solution Approach 1:
The patent applies local quality by limiting the shielding function to specific peripheral areas where wiring patterns are located, rather than forming a continuous shielding layer across the entire device. The decorative layer is designed to provide shielding only in the necessary peripheral zones, eliminating the need for additional insulating layers and reducing overall device thickness while maintaining ease of manufacture.
4Reliability
If metal plate shielding member is used to cover wiring pattern disposition area, then erroneous detection is prevented, but thickness and weight of input device increase
Solution Approach 1:
The patent uses a thin-film approach by forming the shielding function within the decorative layer itself, which is a thin printed layer on the base material. This replaces the need for thick metal plate shielding members, significantly reducing the weight and thickness of the input device while maintaining effective electrostatic shielding and preventing erroneous detection.
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 achieves a high light-blocking effect without thickening the decorative layer, prevents erroneous detection, and maintains a thin, lightweight structure by using the same conductive material for shielding and wiring patterns, thereby enhancing the overall performance and design of the input device.
Implementation Method 1
non-light-transmissive conductive shielding layers formed from the same material as the wiring patterns, which vertically overlap the wiring patterns on both surfaces, functioning as effective shields
Implementation Method 2
In the electrostatic capacitive type, a light-transmissive X conductive layer extending in the X direction and a light-transmissive Y conductive layer extending in the Y direction oppose each other in a detection area, and a potential is alternately applied to the X conductive layer and the Y conductive layer. When a finger of a person substantially at a ground potential approaches, an electrostatic capacitance is formed between the X and Y conductive layers and the finger
Data Source
AI summary
A lower surface and an upper surface are provided in a detection panel 2. Lower electrode layers 11a and 11b, a lower wiring pattern 15, and a lower land portion 13 formed on the lower surface are covered with upper shielding layers 28a and 28c of the upper surface, and an upper electrode layer 21, an upper wiring pattern 25, and an upper land portion 23 formed in the upper surface are covered with lower shielding layers 19a and 19b of the lower surface. Therefore, an effect of a decorative area shielding light may be enhanced, and thus an electrical shielding effect may further be exhibited.