The **FLM-41-R** is an Electronic Shutter Unit commonly used in high-precision thermal imaging cores, specifically those manufactured by **InfiRay (Raytron)**. Its primary function is to provide internal calibration for Uncooled Focal Plane Array (UFPA) sensors. --- ### 1. Technical Specifications The FLM-41-R acts as a mechanical "Non-Uniformity Correction" (NUC) mechanism. | Feature | Description | | :--- | :--- | | **Component Type** | Electromechanical Solenoid Shutter | | **Compatible Core** | InfiRay Micro II Series (e.g., 384/640 resolutions) | | **Driving Voltage** | Typically 3.3V - 5V DC | | **Function** | Image calibration and sensor protection | | **Control Interface** | Pulse Width Modulation (PWM) or GPIO trigger | --- ### 2. Core Electronic Components The device consists of three main electronic sub-assemblies: #### A. The Electromagnetic Actuator (Solenoid) This is the "motor" of the part. It uses a copper coil that, when energized, creates a magnetic field to move a metal arm. * **Bi-stable design:** It often uses a permanent magnet to hold the shutter in the open or closed position without consuming continuous power. * **Switching Speed:** Designed for millisecond response times to minimize "freeze" time during video feeds. #### B. The Shutter Blade (The Reference Target) While it looks like a simple piece of plastic or metal, it is electronically significant: * **Emissivity Coating:** The surface is coated to provide a uniform thermal signature. * **Temperature Sensor (Thermistor):** Often paired with an onboard NTC thermistor so the camera's CPU knows the exact temperature of the shutter blade to use as a baseline for calibration. #### C. Connector Interface The unit connects to the thermal core's PCB via a flexible flat cable (FFC) or a small 2-pin/4-pin micro-connector. * **Pins 1-2:** Solenoid Drive (Polarity reversal swaps open/closed state). * **Pins 3-4 (Optional):** Feedback loop or thermistor data. --- ### 3. Electronic Working Principle The FLM-41-R operates through a process called **Non-Uniformity Correction (NUC)**: 1. **Trigger:** The camera software detects a drift in pixel voltage (due to heat buildup). 2. **Actuation:** The driver circuit sends a short current pulse to the FLM-41-R coil. 3. **Blocking:** The blade moves in front of the sensor, blocking external IR radiation. 4. **Sampling:** The sensor reads the "flat" thermal profile of the blade. 5. **Reset:** The software offsets every pixel to match this uniform value, and the shutter retracts. --- ### 4. Integration Diagram ```mermaid graph LR A[Main Processor] -- PWM Signal --> B[Motor Driver IC] B -- Current Pulse --> C[FLM-41-R Solenoid] C -- Moves Blade --> D[Optical Path] D -- Feedback --> A ```