LED Device Specification - Revision 3 - Lifecycle Information - Chinese Technical Documentation

1. Product Overview

Mwongozo huu wa Vigezo vya Kiufundi unatoa taarifa kamili kuhusu kifaa maalum cha LED (Light Emitting Diode). Waraka huu upo katika toleo la tatu la marekebisho, linaloonyesha kwamba vipimo vya bidhaa vimekomaa na vimeganda. Hatua ya maisha yake imebainishwa kama "Toleo la Marekebisho", ambayo kwa kawaida inamaanisha bidhaa iko katika hatua ya uzalishaji hai, vigezo vimekamilika, na mabadiliko yoyote yanasimamiwa kupitia mchumo rasmi wa udhibiti wa marekebisho. Tarehe ya kutolewa kwa toleo hili la marekebisho imerekodiwa kuwa Desemba 5, 2014, na kipindi cha kumalizika kimetiwa alama kama "Daima", ikimaanisha kwamba toleo hili la mwongozo wa vigezo litakuwa na uhalali usio na kikomo, isipokuwa litabadilishwa na toleo jipya la marekebisho. Kifaa hiki kimeundwa kwa makusudi ya kufikia uaminifu wa juu na matumizi ya muda mrefu katika matumizi mbalimbali ya elektroniki.

1.1 Core Advantages

Based on its stable revision status, the core advantages of this device include: proven reliability, consistent performance parameters, and mature manufacturing processes. A product in the "Revision" stage with a "Permanent" validity period indicates an extremely high level of design maturity, reducing the risk of unforeseen performance variations. This makes it an ideal choice for application scenarios requiring long-term supply chain stability and predictable performance.

1.2 Target Market

This LED device is suitable for a wide range of fields, including consumer electronics, industrial control, automotive interior lighting, signage, and general lighting. Its mature lifecycle status makes it particularly attractive for products with long development cycles or components that require guaranteed long-term supply.

2. In-depth Analysis of Technical Parameters

Although the provided excerpt focuses on document metadata, a complete LED device specification will include detailed technical parameters. The following section outlines typical parameter categories that are usually subjected to in-depth analysis.

2.1 Photometric and Color Characteristics

Detailed analysis of LED light output is crucial. This includesLuminous flux, measured in lumens (lm), represents the total perceived power of emitted light.Luminous intensity, measured in millicandelas (mcd) at a specified viewing angle, defines the brightness in a particular direction. For white LEDs, theirDominant wavelength或Correlated Color Temperature (CCT)Specifies the color of the emitted light.Color Rendering Index (CRI)，特别是对于白光LED，表示光源相对于自然光揭示物体真实颜色的准确度。高显色指数（例如>80）对于零售照明或美术馆等应用至关重要。

2.2 Electrical Parameters

Electrical characteristics define the operating conditions.Forward Voltage (Vf)It refers to the voltage drop across an LED when it emits light under the specified forward current. This parameter is temperature-dependent.Forward Current (If)It is the recommended operating current, typically given as a continuous DC value. Exceeding the maximum rated forward current will significantly shorten the LED's service life.Reverse Voltage (Vr)It is the maximum voltage that an LED can withstand when biased in the non-conducting direction; exceeding this value may cause immediate and irreversible damage.

2.3 Thermal Characteristics

The performance and lifespan of an LED are greatly affected by temperature.Junction Temperature (Tj)It is the temperature of the semiconductor chip itself. Maintaining the junction temperature below its maximum rating is key to ensuring reliability.Thermal Resistance (Rth_j-a), measured in degrees Celsius per watt (°C/W), indicates the efficiency of heat conduction from the LED junction to the surrounding environment. A lower thermal resistance means better heat dissipation capability, which is crucial for maintaining light output and lifespan, especially in high-power applications.

3. Grading System Description

Subtle variations naturally occur during the LED manufacturing process. Binning is the process of classifying LEDs into groups (bins) based on key parameters to ensure consistency within a production batch.

3.1 Wavelength/Color Temperature Grading

LEDs are binned according to their dominant wavelength (for colored LEDs) or correlated color temperature (for white LEDs). This ensures that LEDs used in the same assembly (such as a light panel or display) have nearly identical color output, preventing visible color differences or uneven illumination.

3.2 Luminous Flux Binning

LEDs are sorted based on their light output (lumens) at a standard test current. This allows designers to select bins that meet the specific brightness requirements of their application, ensuring brightness consistency across multiple devices or batches.

3.3 Forward Voltage Binning

Sorting by forward voltage (Vf) helps design efficient drive circuits. When multiple LEDs are connected in series, using LEDs from the same or similar Vf bins ensures more uniform current distribution, thereby improving overall system efficiency and reliability.

4. Performance Curve Analysis

Graphical data provides deeper insights into LED behavior under different conditions.

4.1 Current-Voltage (I-V) Characteristic Curve

The I-V curve shows the relationship between forward current and forward voltage. It is nonlinear, exhibiting a characteristic "knee" voltage below which the current is minimal. This curve is crucial for designing current-limiting circuits (e.g., resistors or constant current drivers) to ensure stable operation.

4.2 Temperature Dependence

Graphs showing luminous flux or forward voltage versus junction temperature are essential. Luminous flux typically decreases as temperature increases. For most LEDs, forward voltage also decreases with increasing temperature. Understanding these relationships is key to thermal management design.

4.3 Spectral Power Distribution

For white LEDs, this graph shows the intensity of emitted light at each wavelength. It reveals the peak of the blue excitation LED and the broader phosphor emission spectrum, aiding in understanding the color quality and Color Rendering Index of the light source.

5. Mechanical and Packaging Information

The physical dimensions and structure of the LED package are crucial for PCB (Printed Circuit Board) design and assembly.

5.1 Outline Dimension Drawing

Detailed mechanical drawings provide precise dimensions, including length, width, height, and any critical tolerances. These drawings ensure that components can be correctly installed into the designated space on the PCB and within the final product enclosure.

5.2 Pad Layout Design

It provides the recommended PCB pad pattern (footprint), showing the dimensions, shape, and spacing of the copper pads to which the LED will be soldered. Adhering to this design is crucial for achieving reliable solder joint connections and proper alignment.

5.3 Polarity Marking

Clear markings indicate the anode (+) and cathode (-) terminals. Typically shown via diagrams featuring a notch, a dot, a longer lead, or differently shaped pads. Correct polarity is necessary for the LED to function properly.

6. Welding and Assembly Guide

Proper operation and assembly are crucial to prevent damage.

6.1 Reflow Soldering Temperature Profile

It provides the recommended reflow soldering temperature profile, including the rate and duration of the preheating, soaking, reflow (peak temperature), and cooling stages. Following this profile prevents thermal shock, which may cause the LED package to crack or damage the internal chip.

6.2 Precautions and Operating Specifications

The guidelines include warnings against applying mechanical stress, the importance of using ESD (Electrostatic Discharge) protection during handling, and avoiding contamination of the LED lens. They also specify cleaning methods compatible with the packaging materials.

6.3 Storage Conditions

It provides recommended storage temperature and humidity ranges to prevent degradation of LED materials (such as epoxy resin lenses or internal bonds) before use. It may also include Moisture Sensitivity Level (MSL) information, specifying the baking requirements necessary if the packaging is exposed to moisture.

7. Packaging and Ordering Information

This section details how the product is supplied and the method for specifying it when ordering.

7.1 Packaging Specifications

It describes the packaging form, such as tape and reel, tube, or tray. Details including reel dimensions, pocket pitch, and component orientation on the tape are included, which are necessary for automated assembly equipment setup.

7.2 Label Information

It explains the information printed on the packaging label, typically including part number, quantity, lot code, date code, and binning information.

7.3 Part Number Coding System

Analyze the part number structure to show how different digits or letters in the complete part number correspond to specific attributes, such as color, luminous flux bin, voltage bin, packaging type, and special functions.

8. Application Recommendations

8.1 Typical Application Circuit

Provides circuit diagram examples for driving LEDs, such as using a simple series resistor in low-current applications, or a constant current driver in applications requiring higher performance and stability. May also show configurations for series/parallel arrays.

8.2 Key Design Considerations

Key design recommendations include: calculating the appropriate current-limiting resistor, ensuring sufficient heat dissipation (especially for high-power LEDs), considering optical design to achieve the desired beam distribution, and protecting against voltage transients or reverse polarity connections.

9. Technical Comparison

This section will objectively compare key parameters of this LED—such as luminous efficacy (lumens/watt), Color Rendering Index (CRI), thermal resistance, and package size—against typical industry product lines or previous-generation products. Its stable "Revision 3" status itself is a comparative advantage, indicating it is an optimized, reliable product.

10. Frequently Asked Questions (FAQ)

Based on common technical questions regarding LED datasheets.

Q: What does "Lifecycle Stage: Revision" mean?
A: This indicates the product is in the mature stage of its lifecycle. The design is stable and in active production. Changes are managed through formal revision updates to documentation, ensuring traceability.

Q: Why is the "Expiration Date: Permanent"?
A: This means there is no scheduled expiration date for this specific revision of the specification. The information contained will serve as the official specification for this product revision unless explicitly superseded by a new version of the document.

Q: How to understand the absence of specific technical values in the provided excerpt?
A: The provided text is metadata from the document header. The complete datasheet will have separate, detailed sections for optical, electrical, and mechanical specifications. Always refer to the full document for parameters when making critical design decisions.

11. Practical Application Cases

Scenario: Designing a Backlight Unit for an Industrial Display
A designer needed to provide uniform and reliable backlighting for a 7-inch display used in a factory environment. He selected this LED based on its mature revision status to ensure long-term supply for future repairs. He utilized luminous flux binning information to procure LEDs from a single, narrow bin, ensuring consistent brightness across the entire panel. Thermal resistance data was used to design an aluminum heat sink to maintain a low junction temperature, ensuring stable light output and maximizing lifespan in a potentially hot environment. Mechanical drawings ensured the LED could be precisely installed into the light guide plate assembly.

12. Working Principles

An LED is a semiconductor diode. When a forward voltage is applied across its terminals (anode positive relative to the cathode), electrons from the n-type semiconductor material recombine with holes from the p-type material at the junction between them. This recombination releases energy in the form of photons (light). The specific wavelength (color) of the emitted light is determined by the energy band gap of the semiconductor material used (e.g., gallium nitride for blue light, gallium arsenide phosphide for red light). White LEDs are typically made by coating a blue LED chip with yellow phosphor; some of the blue light is converted to yellow light, and the mixture of blue and yellow light is perceived as white by the human eye.

13. Technology Development Trends

LED industry continues to develop. Key trends include continuously improvingluminous efficacy(more lumens per watt), thereby achieving higher energy efficiency. The industry places high emphasis on enhancingcolor quality, high CRI LEDs are becoming more widespread.MiniaturizationContinuous development enables direct-view displays to achieve higher pixel density.UV-C LED(For disinfection) andMicro-LED(For next-generation displays) development represents a significant technological frontier. Furthermore, integrating control electronics directly into the LED package ("smart LED") is simplifying system design for tunable-color and interconnected lighting applications.