With the development of autonomous driving technology and the acceleration of automotive intelligence, there is an increasing amount of information that needs to be displayed in vehicles, leading to a growing number of screens. Looking at the new cars released today, the trend of large screens and multiple displays in cars is inevitable.

SAIC Feifan R710.25-inch mini instrument screen, 15.05-inch OLED, 12.3-inch mini co-driver screen

Based on the characteristics of these screens, they can roughly be divided into four types: LCD, OLED, Mini LED, and Micro LED. Among these four types of screens, Mini LED has captured everyone’s attention in the past two years.

1. What is Mini LED?

First, let’s briefly review what Mini LED is. Mini LED, also known as “sub-millimeter light-emitting diode,” refers to LED devices with chip sizes ranging from 50 to 200μm. It is a refined result between small pitch LED and Micro LED. Mini/Micro LED is a product of the fine development of LED displays, and as the technical path becomes clearer, it will become a new blue ocean for LED display applications.

Huiwei Technology’s official website introduction about Mini LED backlight panels

Compared to the current mainstream display technology LCD, Mini LED offers better display effects, a significant improvement in response speed, allows for thinner screens, and greatly reduces power consumption, which can extend battery life.

In comparison with OLED displays, Mini LED has a faster response speed and higher temperature reliability while maintaining excellent display effects and flexibility. The significant feature of Mini LED compared to small pitch LED is its depackaging, primarily targeting the high-end small pitch LED market, allowing for higher resolution and display effects.

2. Distinguishing Backlight and Direct Display from Different Mini LED Solutions

Mini LED as backlight is essentially still LCD, while direct display uses Mini LED to directly display graphics. By controlling the direction of the liquid crystal molecules in the liquid crystal board circuit, the backlight (different colors) is projected onto the display screen.

Mini LED backlight (blue layer)

Mini direct display is a combination of Mini RGB three-color chips, while Mini backlight consists of Mini blue light chips + QD, converted into white light for backlighting behind the liquid crystal.

Introduction to Tianma direct display screen:

2. Comparison of Four Display Technologies

Currently, the aforementioned four display technologies each have their own advantages and disadvantages. Overall, the next generation of displays should theoretically be self-emitting, capable of flexible display shapes, and the development of Micro LED/OLED. However, due to some production issues with the aforementioned two technologies, Mini LED backlight technology has become a hot topic solution. Below is a simple comparative introduction to these four solutions.

1. LCD

The LCD backlight layer usually consists of dozens to hundreds of LED beads larger than 200μm. These LED beads are either fully on or fully off and cannot be controlled individually. All pixel points of the LCD screen share a large backlight layer.

Cross-section diagram of an LCD pixel point

LCD display panels are relatively low in cost, and they have advantages such as small volume, light weight, and low energy consumption. The technology is also relatively mature, with a low failure rate.

2. OLED

QLED (Quantum Light Emitting Diode) has unique optical characteristics and can display different colors based on particle size after being powered. It also has long lifespan, wide color gamut, high brightness, and pure colors.

Compared to LCD, the advantages of OLED screens mainly include the ability to display pure black, no light leakage, near-infinite contrast, short response time, flexibility, low power consumption, and short response time. The disadvantages of OLED screens compared to LCD mainly include short lifespan, screen flicker, and low pixel density.

3. Mini LED

Mini LED miniaturizes the LED beads in the backlight layer of LCD screens, with each LED bead size ranging from 50 to 200μm, allowing for more backlight beads to be packed into the backlight layer, providing better brightness and uniformity. Mini LED divides the backlight layer into small segments and adjusts the light through LED chips, thereby improving the black-and-white contrast issue that LCD has been criticized for, achieving display effects close to OLED while avoiding lifespan issues.

4. Micro LED

Micro LED can be said to integrate all the advantages of LCD and OLED, featuring high picture quality, low energy consumption, and long lifespan, but the manufacturing process is complex and production costs are high.

Cross-section diagram of a Micro LED pixel point

3. Mini LED Backlight Process Flow

The Mini LED process flow is roughly as follows: sorting, printing, testing, die bonding, testing, rework, testing, etc.

Information source: Global Robot Information

The Guangdong Micro Display Industry Technology Innovation Alliance (MiLEDA) is a technology innovation demand-oriented alliance, focusing on technology exchange and cooperation among member enterprises. Under the leadership of Professor Sun Xiaowei, the alliance strives to promote communication between academia and industry and actively become an important platform for industry-academia-research exchange in the field of micro displays in Guangdong.