Card-Type Lamp Substrate Warpage Control
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Solution Overview
Problem
The substrate sheet for card-type lamp units experiences warpage near the connector portion due to heat treatment, caused by the difference in linear expansion coefficients between the resin card-type light source and the metal heat dissipation member.
Innovation Solution
A substrate sheet design that includes a polygonal substrate body with an external connector insertion portion, a heat dissipation member integrated with the substrate body, and a frame body coupled via coupling end portions, which restricts warpage by integrating the connector forming portion with the frame body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If heat treatment is performed on the substrate sheet to form the metal base substrate, then the heat dissipation performance is improved, but warpage is generated in the vicinity of the connector portion due to difference in linear expansion coefficient between resin and metal
Solution Approach 1:
The frame body is coupled to the substrate sheet via coupling end portions before heat treatment is applied. This preliminary coupling creates a restraining structure that counteracts the warpage-tending forces that will arise during thermal expansion, preventing deformation before it occurs.
Solution Approach 2:
The coupling end portions are strategically positioned at specific locations on the substrate sheet (outer peripheral sides and connector forming sides) rather than uniformly across the entire structure. This localized coupling provides targeted restraint where warpage is most likely to occur during heat treatment.
2Shape
If the coupling end portion is formed between the outer peripheral side of the connector portion and the frame body, then warpage is restricted, but a burr is generated that adversely affects insertion and removal of the connector portion
Solution Approach 1:
The coupling end portion for the frame body is extracted from the outer peripheral side location and repositioned to the connector forming side. This extraction removes the source of the burr problem while maintaining the warpage restriction function through alternative positioning.
Solution Approach 2:
Instead of forming the coupling end portion at the outer peripheral side (conventional approach), the invention inverts the approach by forming it at the connector forming side. This reversal of positioning strategy simultaneously achieves warpage restriction without creating interference burrs.
3Ease of operation
If the coupling end portion is not formed between the connector portion and the frame body, then connector functionality is maintained, but warpage occurs in the vicinity of the connector portion forming portion
Solution Approach 1:
The coupling end portion is positioned on the connector forming side rather than at the outer peripheral side, representing a dimensional repositioning. This spatial reconfiguration allows the coupling to restrain warpage in the connector vicinity without interfering with connector insertion and removal operations.
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 design effectively reduces warpage near the external connector insertion portion, allowing for narrower connector insertion portions and wider connector forming sides, which enhances prevention of warpage and improves connector functionality.
Implementation Method 1
a heat dissipation member (16) which is integrated with the substrate body (10) and has a linear expansion coefficient different from that of the substrate body (10)
Implementation Method 2
a heat dissipation member (16) which is integrated with the substrate body (10) and has a linear expansion coefficient different from that of the substrate body (10)
Data Source
AI summary
A substrate sheet (20) for a card-type lamp unit (5) includes the card-type lamp unit (5) which has a polygonal substrate body (10) having an outer peripheral side (10b to 10d) and a connector forming side (12), an external connector insertion portion (11) formed on the connector forming side (12), a heat dissipation member (16) integrated with the substrate body (10) and having a linear expansion coefficient different from that of the substrate body (10), and a light emitting element light source (6) connected to a control circuit (13) for light ON/OFF and a frame body (23) integrated with the card-type lamp unit (5) via a coupling end portion (10e) formed on the outer peripheral side of the substrate body (10), in which a coupling end portion (21, 22) for the frame body (23) is provided on the connector forming side (12).