I. What does SMD Chip LED mean?

1. SMD LED stands for Surface Mounted Device Light Emitting Diode, which is a solid-state semiconductor device that directly converts electrical energy into light.

2. The heart of an LED is a semiconductor chip. One end of the chip is attached to a bracket, with one end being the negative pole and the other end connected to the positive pole of the power supply, encapsulating the entire chip in epoxy resin.

3. The semiconductor chip consists of two parts: one part is the P-type semiconductor, where holes dominate, and the other part is the N-type semiconductor, where electrons dominate.

4. When these two semiconductors are connected, they form a P-N junction.

5. When current passes through the conductor and acts on this chip, electrons are pushed into the P-region. In the P-region, electrons combine with holes, and then energy is emitted in the form of photons. This is the principle of LED light emission.

6. The wavelength of light, which determines its color, is determined by the materials forming the P-N junction.

II. Specifications and Models of SMD Chip LEDs

SMD chips are generally divided into:

1. Front-emitting: 3020, 3528, 5050, 3014, 0402, 0603, 0805, 1206, 3014, 5630, 5730, 7020, etc.

2. Side-emitting light sources: 0603, 0805, 1016, 1024, 4018, etc.

SMD chip power: 0.06W, 0.2W, 0.3W, 0.5W, 1W, etc.

III. Composition of SMD Chip LEDs

All LED emissions are similar, only the appearance of the brackets is different. The composition of SMD chip LEDs includes: brackets, light cores, and ICs.

1. The semiconductor chip consists of two parts: one part is the P-type semiconductor, where holes dominate, and the other part is the N-type semiconductor, where electrons dominate.

2. When these two semiconductors are connected, the holes in the P-type semiconductor will drift towards the N-region and combine with the free electrons there. Similarly, the electrons in the N-type semiconductor will drift towards the P-region and combine with the holes there. Thus, since the P-region loses holes and carries a negative charge, and the N-region loses electrons and carries a positive charge, an electrostatic field is formed, hindering the drift of electrons and holes, forming a "P-N junction" between them.

3. When current passes through the conductor and acts on this chip, electrons are pushed into the P-region. In the P-region, electrons combine with holes, and then energy is emitted in the form of photons. This is the principle of LED light emission.

4. The wavelength of light, which determines its color, is determined by the materials forming the P-N junction. White light-emitting LEDs emit white light because the chip emits blue light, which excites the yellow phosphor applied, resulting in white light (blue + yellow = white).

IV. SMD LED Chip

Surface mount LEDs, also known as SMD LEDs, are a type of LED chip.

LEDs are generally divided into three types:

1. Direct plug-in low power, with various specifications.

2. SMD surface mount.

3. High-power LEDs.

V. Encapsulation of Surface Mount LEDs, LED Encapsulation Process

LED encapsulation process: Steps

1. Cleaning: Use ultrasonic cleaning of PCB or LED brackets, and dry them.

2. Mounting: After applying silver adhesive to the bottom electrodes of the LED chip, expand the chip. Place the expanded chip on the crystal plate, and use a crystal pen under a microscope to install the chip one by one on the corresponding solder pads of the PCB or LED. Then, sinter to solidify the silver adhesive.

3. Welding: Use aluminum wire or gold wire soldering machine to connect the electrode to the LED chip as lead for current injection. LEDs directly mounted on PCBs generally use aluminum wire soldering machines.

4. Encapsulation: Protect the LED chip and solder joints with epoxy through dispensing. Dispensing on the PCB requires strict requirements for the shape of the cured adhesive, which directly affects the brightness of the backlighting product. This process also involves applying phosphors.

5. Soldering: If the backlight source uses SMD-LEDs or other encapsulated LEDs, they need to be soldered to the PCB before assembly.

6. Film cutting: Use a punch press to cut various diffusion films, reflective films, etc., required for the backlight source.

7. Assembly: According to the drawings, manually install various materials of the backlight source in the correct positions.

8. Testing: Check the photometric parameters and uniformity of the backlight source.

9. Packaging: Package the finished products as required and put them into storage.

How are LED chips produced?

The entire production process of LED chips is divided into epitaxial wafer production, chip production, and LED chip encapsulation. The entire process reflects the level of modern electronic industry manufacturing technology. LED manufacturing integrates multiple technologies, making it a high-tech product. Understanding how LED chips are produced is also necessary for knowledge of LED lighting applications.

1. LED epitaxial wafer production process:

LED epitaxial wafer growth technology mainly uses metal organic chemical vapor deposition (MOCVD) to produce synthetic materials with semiconductor properties, which are the raw materials for manufacturing LED chips.

2. LED chip production process:

LED chips are manufactured using epitaxial wafers and are devices that provide LED chip encapsulation, which is the key to LED chip quality.

3. LED chip encapsulation process:

LED chip encapsulation is the process of encapsulating chips on corresponding brackets according to the requirements of LED chip applications, which determines the cost-effectiveness of LED chips and is crucial for the quality of LED lighting products.

VI. How to Use Surface Mount LED Chips

How to Replace Surface Mount LED Chips

Voltage of Surface Mount LED Chips

1. The voltage of red light emitted by LED chips is generally 1.8V-2.2V.

2. The voltage of white light emitted by LED chips is generally 2.8V-3.3V.

3. The voltage of yellow-green light emitted by LED chips is generally 1.8V-2.2V.

4. The voltage of emerald green light emitted by LED chips is generally 2.8V-3.3V.

5. The voltage of orange light emitted by LED chips is generally 1.9V-2.4V.

6. The voltage of blue light emitted by LED chips is generally 3.0V-3.4V.

7. The voltage of purple light emitted by LED chips is generally 3.0V-3.4V.

8. The voltage of pink light emitted by LED chips is generally 3.0V-3.4V.

9. The voltage of infrared LED chips is generally 1.3-1.8V.

VII. Power of Surface Mount LED Chips

1. Hat-shaped, surface mount 3528, etc., with a power of 0.06W and a current of about 20mA. Surface mount 3014 with a power of 0.1W and a current of about 30mA.

2. Hat-shaped, surface mount 2835, 5050, etc., with a power of 0.2W and a current of about 60mA.

3. Surface mount 2835, 5630, 5730, core 5050, etc., with a power of 0.5W and a current of about 150mA.

4. Single 1W, lens-encapsulated 5050, top-emitting encapsulated, etc., with a current of about 350mA.

5. Single 3W with a current of about 1000mA.

6. Single 5W with a current of about 1500mA.

7. The power of LED modules depends on the number of chips and their combination mode (series or parallel).

VIII. Difference Between Surface Mount and LED Chips

Difference between LED Chips and Surface Mount

1. Angle: The angle of LED chips is very small, resulting in concentrated light and a long range but limited illumination area; while surface mount LEDs generally have a larger angle, resulting in scattered light and a wide illumination range but a shorter range.

2. Light emission principle: LED chips use discharge for light emission, while surface mount LEDs use cold light emission.

3. Shock resistance: LED chips have inferior shock resistance compared to surface mount LEDs.

4. Light color: LED chips can emit various colors such as red, orange, yellow, and green, while surface mount LEDs do not have this capability.

5. Environmental protection: LED chips do not contain harmful metals, while in comparison, the environmental protection aspect of surface mount LEDs needs improvement.

IX. Comparison Table of Surface Mount LED Chip Models

Common specifications and parameters of LED surface mount chips: 0603, 0805, 1210, 3528, 5050 are all referring to light-emitting components commonly used on LED light strips.

The size of LEDs (imperial/metric) is named as follows:

For example, 0603 means a length of 0.06 inches and a width of 0.03 inches. However, it should be noted that 3528 and 5050 are in metric units.

Here are detailed descriptions of these specifications:

0603: Equivalent to 1608 in metric, meaning the length of the LED component is 1.6mm and the width is 0.8mm. Industry designation is 1608, and imperial designation is 0603.

0805: Equivalent to 2012 in metric, meaning the length of the LED component is 2.0mm and the width is 1.2mm. Industry designation is 2112, and imperial designation is 0805.

1210: Equivalent to 3528 in metric, meaning the length of the LED component is 3.5mm and the width is 2.8mm. Industry designation is 3528, and imperial designation is 1210.

3528: This is the metric designation, meaning the length of the LED component is 3.5mm and the width is 2.8mm. Industry designation is 3528.

5050: This is the metric designation, meaning the length of the LED component is 5.0mm and the width is 5.0mm. Industry designation is 5050.

Currently, most manufacturers produce surface mount LED strips mainly using 3528, 5050, 3535, and 5630 chips, with many also using these chips in automotive lighting applications.