Transformer Eddy Current Reduction in LCD Housing
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Solution Overview
Problem
In liquid crystal display (LCD) devices, the leakage flux from transformers mounted on a circuit board generates eddy currents in conductive lower housing members, leading to heat generation, increased power consumption, and noise, which degrade the quality of the displays.
Innovation Solution
The display apparatus incorporates a lower housing member with defined regions and holes to minimize eddy currents, featuring a primary and secondary winding transformer with an insulating section, and a heat dissipation pad, ensuring the transformers are separated from the conductive material to reduce leakage flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If transformers are mounted on a circuit board attached to a conductive lower housing member, then the display apparatus can be compact and efficiently assembled, but eddy currents are generated in the lower housing member by leakage fluxes, causing heat generation, increased power consumption, and noise
Solution Approach 1:
A non-conductive sheet is introduced as an intermediary layer between the transformer and the conductive lower housing member. This mediator blocks the magnetic flux path to the conductive material, preventing eddy current generation while maintaining the compact assembly structure and efficient mounting configuration.
Solution Approach 2:
The lower housing member is divided into a conductive portion and a non-conductive portion, with the non-conductive sheet creating a segmented magnetic path. This segmentation isolates the conductive material from the transformer's leakage flux, eliminating eddy currents while preserving the structural benefits of the conductive housing.
2Strength
If the lower housing member includes conductive material for structural integrity and grounding, then mechanical strength and electrical grounding are improved, but leakage flux from transformers generates eddy currents leading to heat and noise
Solution Approach 1:
The lower housing member is designed with different material properties in different regions: a conductive portion for structural support and grounding, and a non-conductive portion (or covered area) where the transformer is mounted to prevent eddy currents. This local differentiation allows the conductive material to provide strength while avoiding harmful eddy current generation in the critical area.
Solution Approach 2:
A non-conductive sheet serves as a mediator between the transformer and the conductive lower housing member. This intermediary allows the conductive housing to maintain its structural integrity and grounding functions while preventing the magnetic flux from inducing eddy currents in the conductive material.
3Length of moving object
If transformers are placed close to the lower housing member to achieve a slim design, then the display apparatus thickness is reduced, but leakage flux generates stronger eddy currents in the housing member
Solution Approach 1:
A non-conductive sheet is placed between the transformer and the lower housing member, enabling the transformer to be positioned close to the housing for a slim profile while the non-conductive material blocks the magnetic flux path, preventing eddy current generation even at close proximity.
Solution Approach 2:
The lower housing member has a non-conductive characteristic in the region where the transformer is mounted, allowing close placement for slim design while preventing eddy currents. The conductive properties are maintained in other regions for structural purposes.
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 minimizes eddy currents, reducing heat generation, power consumption, and noise, thereby enhancing the quality and efficiency of the LCD devices while maintaining a slim design.
Implementation Method 1
a transformer disposed under the display panel and including a primary winding and a secondary winding which are separated from each other, and an insulating section between the primary winding and the secondary winding
Implementation Method 2
an eddy current may be generated in the lower housing member by the leakage fluxes of the transformers mounted on the circuit board which is attached to the lower housing member
Data Source
AI summary
A display apparatus includes a display panel, a transformer disposed under the display panel and including a primary winding and a secondary winding which are separated from each other and an insulating section between the primary winding and the secondary winding, and a lower housing member on which the display panel is placed and to which the transformer is fixed. A first region corresponding to the insulating section of the transformer is defined in the lower housing member, and at least one hole is disposed in the first region of the lower housing member.