Miniaturized LED Unit for Endoscopes Using Embedded Conductor
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Solution Overview
Problem
The miniaturization of medical endoscopic instruments is limited by the lateral area of existing LEDs, which is often greater than 0.5 mm^2 due to the need for a base element to support bonding wires for electrical connections, hindering the development of minimally invasive devices.
Innovation Solution
An ultra-miniaturized light-emitting unit with a lateral area of 0.5 mm^2 or less is achieved by using a flexible printed circuit board with an L-shaped insulating element that embeds a conductor, eliminating the need for a bonding wire and allowing the semiconductor element to be p-doped with a reflective metal layer for efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a base element with bonding wires is used to electrically connect the LED chip, then reliable electrical connection is achieved, but the lateral surface area exceeds 0.5 mm²
Solution Approach 1:
The patent merges the electrical connection function and mechanical support function into a single integrated flexible printed circuit board structure. The conductor element embedded in the insulating element provides both electrical connectivity and structural support, eliminating the need for separate bonding wires and base element, thus achieving lateral dimensions that do not exceed the LED chip itself.
Solution Approach 2:
The patent replaces the traditional mechanical bonding wire system with an embedded conductor element in a flexible printed circuit board. This substitution integrates the electrical connection into the structural framework, eliminating protruding bonding wires and reducing the overall lateral footprint to within the chip boundaries.
2Area of stationary object
If the lateral surface area of the LED is reduced to minimize invasiveness, then minimally invasive insertion is improved, but electrical connection becomes more difficult
Solution Approach 1:
The conductor element is pre-embedded in the insulating element during manufacturing, establishing electrical connection pathways before the LED chip is mounted. This preliminary integration of conductors into the structural framework simplifies subsequent assembly and ensures reliable electrical connections even in the miniaturized configuration.
Solution Approach 2:
The flexible printed circuit board acts as an intermediary structure that provides both mechanical support and electrical connectivity. The embedded conductor element serves as the mediator between the power supply terminals and the LED chip, enabling electrical connection within the constrained lateral dimensions without requiring external bonding wires.
3Reliability
If bonding wires are used for electrical connection, then electrical connectivity is achieved, but lateral expansion beyond the chip occurs
Solution Approach 1:
The conductor element is nested within the insulating element of the flexible printed circuit board, with both components contained within the lateral boundaries of the LED chip. This nested configuration provides electrical connectivity without any lateral expansion beyond the chip footprint, as the conductors are hidden within the insulating 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
This design minimizes the lateral expansion of the light-emitting unit, enabling the creation of smaller, more invasive medical endoscopic instruments with improved light emission efficiency and reduced mechanical stress during assembly.
Implementation Method 1
The semiconductor element, acting as a diode, is thus subjected to forward current flow, which essentially corresponds to the main radiation direction. Photons are generated in the transition region between the n-doped and p-doped areas within the semiconductor element and emitted as light.
Implementation Method 2
Light emitted against the main radiation direction can be reflected back towards the main radiation direction by a reflective metal layer on the contact side of the semiconductor element.
Data Source
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AI summary
The invention relates to an ultra-miniaturized light-emitting unit (1) for a medical endoscopic instrument, wherein the light-emitting unit (1) defines a primary emission direction (H), and a semiconductor element (3), extending in a planar manner substantially orthogonally to the primary emission direction (H), having a light emission side (9) facing the primary emission direction (H) and a contact side (21) facing away from the primary emission direction (H) and an insulating element (5). The insulating element (5) has a first section (27) and a second section (29), which is substantially L-shaped and laterally encompasses the semiconductor element (3), such that a part (31) of the L-shaped second section (29) is supported on the light emission side (9) of the semiconductor element (3), wherein a conductor element (25) is embedded in the insulating element (5) and extends from the first section (27) of the insulating element (5) through the second section (29) of the insulating element (5), wherein a first contact region (49) of the conductor element (25) can electrically contact a first connection terminal (13) in the first section (27) of the insulating element (5) and a second contact region (53) of the conductor element (25) electrically contacts the light emission side (9) of the semiconductor element (3) in the second section (29) of the insulating element (5), and wherein the contact side (21) of the semiconductor element (3) can electrically contact a second connection terminal (15).