Touch Bar Backlight Shielding Structure for Light Leakage Control
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Solution Overview
Problem
Conventional touch input devices, particularly those with backlight modules, suffer from light leakage issues due to poor assembly, which affects the functionality and aesthetics.
Innovation Solution
A touch input device design incorporating a circuit board, illuminant elements, a spacer, light guide plates, a shielding sheet, and a top plate, where the shielding sheet and reflective layer extensions cover the light-leaking edges to prevent light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a backlight module is disposed inside the touch bar to illuminate it, then the touch bar can be illuminated, but light leakage may occur in the touch bar due to poor assembly
Solution Approach 1:
The patent introduces a shielding sheet as an intermediary component between the backlight module and the touch bar surface. This shielding sheet includes a light permeable region that allows light to pass through while other regions block light leakage at the edges. The shielding sheet acts as a mediator that separates the illumination function from the light containment function, solving the light leakage problem while maintaining proper illumination.
Solution Approach 2:
The shielding sheet is segmented into different functional regions: a light permeable region that allows light to pass through to illuminate the touch bar, and light blocking regions that prevent light leakage at the edges. This segmentation allows different parts of the same component to perform different functions - illumination and light containment - simultaneously resolving the contradiction between needing light transmission and preventing light leakage.
2Illumination intensity
If the shielding sheet includes a light permeable region corresponding to the light guide plate, then light can pass through to illuminate the touch bar, but the structure becomes more complex
Solution Approach 1:
The patent merges the light shielding function and the light transmission function into a single shielding sheet component. Instead of using separate components for blocking light and transmitting light, the shielding sheet integrates both functions through its design with light permeable and light blocking regions. This merging reduces the overall number of components while still achieving the desired light control, thus managing complexity.
Solution Approach 2:
The shielding sheet serves multiple functions simultaneously: it blocks light leakage at the edges, allows light transmission through the light permeable region, and provides structural support within the touch bar assembly. This multi-functionality reduces the need for additional separate components, thereby managing device complexity while achieving comprehensive light control.
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
Effectively blocks light leakage, ensuring uniform illumination and enhancing the device's aesthetic appeal by preventing light from escaping the edges.
Implementation Method 1
The shielding sheet includes a main section, a first extension section, and a second extension section. The first extension section covers the light-leaking edge of the spacer and the board edge of the circuit board. By covering the light-leaking edge of the spacer and the board side of the circuit board with the first extension section of the shielding sheet, light from the illuminant elements can be blocked to prevent the leakage of light.
Implementation Method 2
The plurality of light guide plates are disposed in the plurality of accommodation holes, respectively. The light guide plates are positioned between the illuminant elements and the top plate, guiding light from the illuminant elements through the accommodation holes to the light-exit regions of the top plate.
Implementation Method 3
The reflective layer includes a main reflective section, a first extension section, and a second extension section. The first extension section of the reflective layer covers the light-leaking edge of the spacer and the sheet edge of the shielding sheet. The reflective layer reflects light to enhance illumination uniformity and prevent light leakage at edges.
Data Source
AI summary
A touch input device includes a circuit board, a plurality of illuminant elements disposed on the circuit board, a spacer disposed over the circuit board, a plurality of light guide plates, a shielding sheet, and a top plate. The circuit board has a board edge and an upper surface having a plurality of sensing regions. The spacer has a light-leaking edge and a plurality of accommodation holes for accommodating the illuminant elements and the light guide plates. The shielding sheet includes a main section covering the spacer, a first extension section covering the light-leaking edge and the board edge, and a second extension section combined with the circuit board. The main section has a plurality of light permeable regions respectively corresponding to the light guide plates. The top plate is disposed on the main section and has a plurality of light-exit regions.