LED Wavelength Specification Document - Technical Data Sheet - English

1. Product Overview

This technical document provides comprehensive specifications and analysis for a series of LED components. The primary focus of the provided data is on the lifecycle management and key optical parameter, specifically the wavelength. The document indicates a standardized revision control process, ensuring the technical data is current and maintained. The core information revolves around the defined wavelength parameters, which are critical for applications requiring precise spectral output. The target market for such components includes industries utilizing optoelectronic devices for signaling, illumination, sensing, and display technologies where specific wavelength emission is paramount.

2. In-Depth Technical Parameter Interpretation

The provided data snippet highlights several key technical and administrative parameters essential for component identification and lifecycle tracking.

2.1 Lifecycle and Administrative Data

The document consistently lists LifecyclePhase: Revision 2. This indicates the component is in a revision state, specifically the second revision of its technical documentation or design. This is crucial for engineers to ensure they are referencing the correct version of the specifications. The Expired Period: Forever denotes that this revision of the document does not have a planned obsolescence date and is intended to be the authoritative reference indefinitely, or until a new revision is issued. The Release Date: 2013-10-07 11:50:32.0 provides a precise timestamp for when this revision was formally released, allowing for traceability and version control.

2.2 Photometric and Optical Characteristics

The central technical parameter extracted is the wavelength. Two specific notations are present:

• Wavelength λ(nm): This denotes the dominant or peak wavelength of the LED emission, measured in nanometers (nm). This is the wavelength at which the spectral power distribution reaches its maximum intensity. It is the primary descriptor of the LED's color for monochromatic devices.
• Wavelength λp(nm): The 'p' subscript typically stands for 'peak'. In many contexts, λ and λp are used interchangeably to mean peak wavelength. However, in some detailed specifications, λp might be used to specify a particular point on the spectrum, but given the data, it is interpreted here as the peak emission wavelength. The exact value in nanometers is not provided in the snippet, indicating this is a placeholder or header for a data field that would be populated in a full datasheet.

The absence of specific numerical values for these wavelengths in the provided content suggests the document structure includes tables or charts where these values are listed for different product bins or models.

3. Binning System Explanation

Based on the structure mentioning wavelength parameters, a standard practice for LED manufacturing is the implementation of a binning system. LEDs are sorted (binned) after production based on measured characteristics to ensure consistency.

3.1 Wavelength / Color Binning

This is the most critical binning parameter for color LEDs. Due to inherent variations in the semiconductor epitaxial growth process, the peak wavelength of LEDs from the same production batch can vary. Manufacturers measure each LED and group them into specific wavelength ranges (bins). For example, a blue LED might be binned into ranges like 465-470nm, 470-475nm, etc. This allows customers to select LEDs with the precise color required for their application, ensuring color uniformity in a final product like a display or signage.

4. Performance Curve Analysis

While specific curves are not provided in the text, a complete datasheet would include graphical representations critical for design.

4.1 Spectral Distribution Curve

This graph plots relative intensity against wavelength. It visually shows the peak wavelength (λp) and the spectral bandwidth (Full Width at Half Maximum - FWHM), which indicates how pure or monochromatic the light is. A narrower FWHM means a more pure color. This curve is essential for applications in spectroscopy, medical devices, or precise color matching.

4.2 Forward Current vs. Forward Voltage (I-V) Curve

This fundamental electrical characteristic shows the relationship between the current flowing through the LED and the voltage drop across it. LEDs are current-driven devices. The curve typically shows an exponential rise, with a defined forward voltage (Vf) at a specified test current. Understanding this curve is vital for designing the correct current-limiting driver circuit to ensure proper operation and longevity.

4.3 Temperature Dependence Characteristics

LED performance is highly temperature-sensitive. Key parameters that shift with junction temperature include:

• Forward Voltage (Vf): Generally decreases as temperature increases.
• Luminous Intensity / Flux: Decreases as temperature increases.
• Peak Wavelength (λp): Typically shifts slightly (usually to longer wavelengths) as temperature increases. This is crucial for color-critical applications.

Datasheets often include graphs showing normalized intensity vs. junction temperature or wavelength shift vs. temperature.

5. Mechanical and Packaging Information

The provided content does not include mechanical details. A full specification would contain this section with:

• Package Dimensions: Detailed mechanical drawing with all critical dimensions (length, width, height, lead spacing) in millimeters.
• Pad Layout / Footprint: Recommended solder pad pattern for PCB design, crucial for reliable soldering and thermal management.
• Polarity Identification: Clear marking of the anode and cathode, often indicated by a notch, a flat edge, a longer lead, or a marked dot on the package.
• Package Material: Information on the lens material (e.g., silicone, epoxy) and body material, which affects light extraction and reliability.

6. Soldering and Assembly Guidelines

Proper handling is essential for LED reliability. This section would cover:

6.1 Reflow Soldering Profile

A recommended temperature vs. time profile for surface-mount assembly. This includes preheat, soak, reflow (peak temperature), and cooling stages. Exceeding the maximum package temperature or thermal shock can damage the LED or its internal bonds.

6.2 Handling and Storage Precautions

LEDs are sensitive to electrostatic discharge (ESD). Guidelines for ESD-safe handling (wrist straps, conductive foam) should be followed. Recommended storage conditions (temperature, humidity) to prevent moisture absorption (which can cause "popcorning" during reflow) would also be specified.

7. Packaging and Ordering Information

This section details how the components are supplied and how to order them.

7.1 Packaging Specification

Describes the carrier medium, such as tape-and-reel (standard for SMD parts), tube, or tray. It includes specifications like reel diameter, tape width, pocket spacing, and quantity per reel.

7.2 Model Numbering / Part Numbering Rule

Explains the structure of the part number. Typically, a part number encodes key attributes like package type, color (wavelength bin), brightness bin, forward voltage bin, and sometimes special features. For example, a part number might be structured as: [Series][Package][WavelengthBin][FluxBin][VfBin]. Understanding this rule allows engineers to decode a part number and select the exact variant needed.

8. Application Recommendations

8.1 Typical Application Scenarios

LEDs characterized by specific wavelength parameters find use in diverse fields:

• Indicators and Panel Lights: Status indicators on consumer electronics, appliances, and industrial equipment.
• Backlighting: For LCD displays in devices like smartphones, monitors, and TVs, often using blue LEDs with phosphor for white light or specific colors for RGB systems.
• General Lighting: White LEDs (blue chip + phosphor) or color LEDs for architectural, decorative, and mood lighting.
• Automotive Lighting: Signal lights (brake, turn), interior lighting, and increasingly, headlights.
• Sensing and Optical Communication: Infrared (IR) LEDs for remote controls, proximity sensors, and optical data links. Specific wavelength LEDs are used in medical sensors (e.g., pulse oximetry).
• Horticulture: LEDs with specific wavelengths (e.g., deep red, blue) are used to optimize plant growth in indoor farming.

8.2 Design Considerations

• Drive Current: Always drive LEDs with a constant current source, not a constant voltage, to maintain stable light output and prevent thermal runaway. The datasheet will specify the absolute maximum ratings and typical operating current.
• Thermal Management:** The single greatest factor affecting LED lifespan and performance. Adequate heat sinking must be designed to keep the LED junction temperature within specified limits. This involves PCB thermal design (copper pours, thermal vias) and possibly external heat sinks.
• Optical Design: The choice of secondary optics (lenses, diffusers) depends on the desired beam angle and distribution. The LED's native viewing angle (specified in the datasheet) is the starting point.
• Binning Selection: For applications requiring color consistency (e.g., video walls, lighting fixtures), specifying a tight wavelength bin and possibly a tight flux bin is necessary, though it may increase cost.

9. Technical Comparison and Differentiation

While a direct comparison with other products isn't possible from the snippet, key differentiators for LEDs generally include:

• Luminous Efficacy (lm/W): The amount of light output per electrical watt input. Higher efficacy means less energy consumption and heat generation for the same light output.
• Color Rendering Index (CRI): For white LEDs, how accurately they render colors compared to a natural light source. High CRI (>90) is needed for retail, museum, and high-quality residential lighting.
• Reliability and Lifetime (L70, L90): The number of hours before the LED's light output depreciates to 70% or 90% of its initial value under specified conditions. A longer lifetime reduces maintenance costs.
• Color Consistency and Binning Tightness: The range of variation within a bin. Tighter bins provide better uniformity.

10. Frequently Asked Questions (Based on Technical Parameters)

10.1 What does "LifecyclePhase: Revision 2" mean for my design?

It means you are using the second revision of the component's specification. You should verify that any previous designs using Revision 1 are still valid or if there are critical changes (e.g., in dimensions, electrical parameters, or materials) that require a design update. Always reference the latest revision for new designs.

10.2 The wavelength value is not a single number but a bin (e.g., 465-470nm). Which value should I use in my optical simulations?

For rigorous simulation, it is prudent to consider the extremes of the bin. Perform simulations at both the lower and upper limits of the wavelength range to ensure your design (e.g., filter performance, sensor response) works across the entire bin. For a conservative estimate, using the midpoint is common, but understanding the system's sensitivity to wavelength shift is key.

10.3 How critical is thermal management for this component?

Extremely critical for all power LEDs. Excessive junction temperature leads to accelerated lumen depreciation (dimming), color shift (wavelength drift), and ultimately, catastrophic failure. The datasheet's derating curves, which show maximum allowable current vs. ambient temperature, must be strictly followed. Proper PCB layout with thermal pads and vias is not optional for reliable operation.

11. Practical Application Case Studies

11.1 Case Study: Designing a Uniform Backlight Unit

Challenge: Create a backlight for a 10-inch display with perfectly uniform white color and brightness.
Solution Approach:

1. Binning: Select white LEDs from the same flux bin and correlated color temperature (CCT) bin. For even tighter control, use LEDs from the same production lot.
2. Thermal Design: Implement a metal-core PCB (MCPCB) to efficiently spread heat from the LED array, preventing hot spots that cause local color shift and brightness variation.
3. Electrical Design: Use a multi-channel constant current driver that can adjust current to small groups of LEDs to fine-tune brightness uniformity.
4. Optical Design: Use a light guide plate (LGP) and diffuser films optimized for the LED's spatial radiation pattern to achieve even light distribution across the surface.

This case highlights the interdependence of electrical, thermal, optical, and component selection (binning) in a successful LED-based design.

12. Principle of Operation Introduction

Light Emitting Diodes (LEDs) are semiconductor devices that emit light through a process called electroluminescence. When a forward voltage is applied across the p-n junction of the semiconductor material (commonly based on gallium arsenide, gallium phosphide, or indium gallium nitride), electrons from the n-type region recombine with holes from the p-type region in the active layer. This recombination event releases energy. In a standard diode, this energy is released as heat. In an LED, the semiconductor material is chosen so that this energy is released primarily in the form of photons (light particles). The specific wavelength (color) of the emitted light is determined by the bandgap energy of the semiconductor material used in the active region. A larger bandgap results in shorter wavelength (bluer) light, while a smaller bandgap results in longer wavelength (redder) light.

13. Technology Trends and Developments

The LED industry continues to evolve rapidly. Key objective trends include:

• Increased Efficiency and Lumen Output: Ongoing improvements in internal quantum efficiency, light extraction techniques, and phosphor technology continue to push luminous efficacy higher, reducing energy consumption for lighting.
• Miniaturization and High-Density Packaging: The development of smaller package sizes (e.g., micro-LEDs, chip-scale packages) enables higher resolution displays and more compact lighting solutions.
• Improved Color Quality and Consistency: Advances in phosphor materials and binning algorithms are delivering white LEDs with higher Color Rendering Index (CRI) and more consistent color points across production batches.
• Expansion into New Wavelength Ranges: Research into new semiconductor materials (e.g., aluminum gallium nitride for deep UV, various compounds for specific IR wavelengths) is opening new applications in sterilization, sensing, and optical communications.
• Integration and Smart Lighting: LEDs are increasingly being integrated with drivers, sensors, and communication chips (Li-Fi, IoT) to create intelligent, connected lighting systems.
• Reliability and Lifetime: Focus on materials science (e.g., more robust encapsulants, better thermal interfaces) continues to extend the operational lifetime of LED systems, reducing total cost of ownership.

These trends are driven by fundamental material science research and manufacturing process improvements, leading to more capable, efficient, and versatile optoelectronic components.