When you are a project manager or integrator and need to purchase RGB or other products containing RGB LED in bulk, you may be confused about it: How do they work, and how can you choose the parameters for them? This article will give you the answer.
The Working Principle of RGB Color Mixing
Light Emission Principle of RGB LEDs
An RGB LED is composed of three light-emitting diodes: red (R), green (G), and blue (B). Each RGB can emit light of a different wavelength in a single color. By proportionally blending the light intensities of these three colors, any color can be obtained, and this is the principle behind the display’s ability to show different images.
Brightness Control Principle of RGB LEDs
The brightness adjustment of RGB is also the brightness adjustment of the display screen. Its common principles are as follows:
- PWM Dimming: The RGB LED controls the brightness by rapidly and periodically turning the screen on and off. However, PWM dimming may cause flickering, which can lead to visual fatigue and even headaches. It is used in most LED screens.
- DC dimming: It changes the constant brightness of the light bulbs by adjusting the size of the current or voltage passing through the RGB chips. In the DC dimming mode, the light is more stable, less prone to flickering, and causes less visual fatigue, making it suitable for most LCD backlight screens.
Effects of Common Cathode and Common Anode on Displays
Common cathode connection means that the cathodes of the R, G, and B chips are all connected to the GND of the circuit, and when the anodes are applied with positive voltage, the circuit lights up. Since the voltage of each color channel can be independently and precisely controlled, it ensures that red, green, and blue can all emit the preset and accurate light at different brightness levels.
While common anode connection means that the anodes of the R, G, and B chips are all connected to the positive pole of the circuit, and the cathodes are grounded to separately control the lighting of each color. Compared with the common cathode, the common anode connection often does not present various colors. However, it has lower costs and is suitable for scenarios that have low requirements for visual effects, such as advertising screens.
The Role of RGB in Displays
Since each RGB LED can display different colors, by integrating and controlling RGB, different images and texts can be presented on the LED screen. That is to say, the color accuracy of RGB determines whether a screen can display accurate images.
Not only the image presentation, but also the color gamut, refresh rate, and the color consistency of the image are largely determined by the type and quality of RGB LEDs. B. Therefore, when you are choosing an LED screen, it is important to select RGB LEDs of high quality.
Different Package Sizes of RGB LEDs
The package size of RGB is usually expressed in a four-digit form for its length and width. For instance, the 3528 package indicates that the size of the lamp beads is 3.5mm × 2.8mm. Different sizes of LED beads typically bring out different brightness. Common package sizes include 3528, 5050, 2121, and so on.
Different package sizes each have their own advantages. Generally speaking, the larger the size, the higher the RGB power, which is more suitable for outdoor LED screens. While a smaller bead size can achieve a smaller pixel pitch, which allows the screen’s clarity to be higher.
Typical RGB Configurations
According to the degree of integration, RGB can be classified into the following three categories:
Discrete RGB
In the discrete RGB integration mode, the r, g, and b light-emitting diodes are independent, and they are rather than encapsulated in the same housing. The color consistency of discrete RGB is poor, and it does not support small pitch. It has gradually been replaced in the field of display screens. Currently, only a few status indicator lights or screens used for symbol display adopt discrete RGB technology.
Integrated RGB
Integrated RGB refers to the installation method in which R, G, and B chips are packaged in the same LED. The RGB in a lamp bead is uniformly controlled by the module. Currently, non-addressable integrated RGB is always chosen by LED and LCD displays. It brings out high color consistency, clarity, and fast response time.
Addressable Smart RGB
Ordinary integrated RGB can only be uniformly controlled by modules or display driver ICs and cannot be addressed separately. While in addressable integrated mode, each LED bead has an independent address, and the color and brightness can be controlled individually. It is often used in those screens with interactivity requirements or strong creativity, such as stage lighting.
Practical Applications of RGB
LED Displays and LED Video Walls
RGB with different indices can form LED displays and LED video walls with different indices to meet your various needs. For example, small-sized RGB in SMD packaging can be made into most indoor LED displays; high-brightness and high-protection-level RGB can be used for outdoor displays.
Stage Lighting
Stage lighting often needs to output multiple colors within a short time, and bulbs with RGB can meet this requirement. RGB is often used in stage headlights, moving head lights, and spotlights.
Backlighting and Ambient LED Applications
Apart from the LED screens, you can also find RGB in many backlights and ambient lighting, such as display backlighting, keyboard lighting effects, indoor ambient lighting, and architectural and landscape lighting.
Vehicle Interior and Exterior Illumination
The application of RGB in the automotive field is also very common. It is often used for ambient lights, status indicator lights, outline lights, and welcome lights in the storage room, but RGB is generally not used for lighting.
How to Choose RGB for Your LED Display Project?
STEP 1: Clarify Project Requirements
As an integrator or project manager, before making a purchase, you need to pre-confirm these requirements for the display screen:
- Does it need to be placed outdoors?
- Does it need to run all day long?
- How far is the viewing distance?
- How high display performance do you need?
After confirming these core requirements, you can then select the RGB type.
STEP 2: Choose Essential Parameters of RGB LEDs
When choosing RGB, the factors you need to consider include:
- Encapsulation form: If you need a small-pitch display, it is best to use a small-sized RGB in SMD packaging; if you need high-brightness outdoor displays, large-sized DIP and SMD packages are ideal choices.
- Wavelength: A large wavelength deviation can cause obvious color differences on the screen. The wavelength of RGB should be stabilized at around ±2 to 3nm.
- Brightness: Generally, the higher the brightness of RGB, the higher the overall screen brightness. Moreover, to avoid uneven brightness, you should also pay attention to the consistency of brightness.
- Half-Peak angle: The half-peak Angle determines the divergence range of the light beam and the viewing Angle of the screen. A closer viewing distance requires a wider half-peak Angle, generally greater than 120 degrees.
- BIN: BIN is the grade identifier of RGB, and parameters classify it. When making a purchase, it is best for you to ask the supplier to define the BIN range and batch consistency clearly.
- Durability and IP rating: Durability determines the lifespan of RGB chips under extreme conditions, and it decides whether your display can last for several years; The protection level determines the LED’s ability to protect against dust and water. If your display screen will work in an environment with high humidityand a lot of dust, it is best to use an IP rating higher than IP65.
STEP 3: Opt High-Quality RGB LED Brands
The essential services of a reliable RGB supplier include: rich project experience, reliable test reports, strong technical support and after-sales service. Before cooperating with them, you need to ask if they can provide these, and then consider the cost-effectiveness.
FAQs
How to Deal with Different Batch Colors Variations in RGB LEDs?
You can guarantee the batch consistency of RGB by:
- Ask the supplier to provide BIN classification certificates for parameters such as wavelength, brightness, and VF.
- Use a colorimeter or spectrometer to detect the color difference of each module.
- Use a tuner drive and color correction software to reduce screen color difference.
How to Choose the Protection Rating for RGB LEDs?
The last two digits of the IP rating respectively represent the dust-proof rating and the water-proof rating. The higher the value, the stronger the protection capability.
In a dry indoor environment, IP20 is ideal; For outdoor exposed screens, the IP rating within the range of IP54 to IP67 should be selected based on different degrees. For screens with low maintenance frequency, the IP level should also be appropriately increased.
What Are the Color Gamut and Color Temperature of RGB LEDs?
Color gamut refers to the range of colors that RGB can display. The wider the color gamut, the richer the colors that RGB can display. Normal LED screens can cover the sRGB color gamut, and some high-end screens can also cover most of the DCI-93 color gamut.
Color temperature refers to the degree of warmth or coldness of white light. High color temperature leans towards cool white, while low color temperature leans towards warm white.
Can the BIN Accuracy of Outdoor Screens be Reduced?
Yes. The viewing distance of outdoor advertising screens is usually several dozen meters, and the viewers can hardly distinguish the subtle difference of LED beads. Therefore, for screens viewed from a distance, the BIN accuracy can indeed be appropriately reduced.
Final Thoughts
Most of the uses of RGB are for making LED displays. When you need to select RGB for display or other purposes, be sure to pay close attention to their parameters and consistency.
If you want to customise LED displays with high-quality RGB LED, JINGYLED will be your ideal choice. We can provide LED screens for various uses and pixel pitches, which can meet your diverse needs.
If you have any further questions, feel free to contact us!
