OLED vs. LCD: What’s the Difference?

Nowadays, LCD and OLED are the main display technology in HMI applications.

You may hear the conclusion of LCD is better than OLED or OLED is better, which are judged from different perspectives.

In this article, we are trying to give you a complete guide of their comparison, so that you can understand their differences and then choose your suitable display technology.

I. OLED vs. LCD: Market share

LCD occupies the absolute mainstream, OLED breaks through in small and medium-sized consumer products.

According to the data from Frost & Sullivan, in 2020, LCD is the absolute mainstream display panel technology, with shipments accounting for 96% of the global display market share.

Although the overall share of OLED is not large, due to its unique flexible feature, it can meet the needs of curved and foldable screens and is widely used in fashion and emerging electronic products with a small screen, such as mobile, smart wearables, and VR devices.

According to the data from TrendForce, in 2021, the penetration rate of LCD panels in the smartphone industry is 58%, while AMOLED has caught up and reached 42%, as shown in figure 2.

II. OLED vs. LCD: What causes the difference?

The difference between LCD and OLED is largely determined by the product structures and imaging principles.

(1) Structures and imaging principles

● Structures and imaging principles

The full form of OLED is organic light-emitting diode, which is an organic self-luminous material that emits light by itself without the need for a separate backlight or color filter. Each OLED pixel can be assigned three colors red, green, and blue.

The OLED’s organic light-emitting materials are situated between two electrodes.

When the voltage is input, the anode current flows through the device, electron holes are formed. Meanwhile, the cathode injects electrons into the circuit.

When both meet in the organic light-emitting layer, they become excitons and release photons. Consequently, colors are displayed on the screen.

In terms of driving technology, OLEDs can be divided into PMOLED (passive-matrix) and AMOLED (active-matrix).

▪ PMOLED

PMOLED originated from LG.

Its simple structure is beneficial to the production process and cost management in manufacturing. With the fast response feature, It has great development potential in microdevices for simple displays.

However, the PMOLED is still facing the problems of high power consumption and short lifespan. Currently, the common size of the display is limited to around 5-inch.

▪ AMOLED

AMOLED originated from Samsung.

Each pixel is equipped with a TFT (thin-film transistor) switch.

This driving mode is easier to achieve high brightness, high resolution, high color performance, and low energy consumption.

At present, AMOLED is widely used in consumer electronics products and is the main OLED technology on the market application.

LCD (Liquid Crystal Display)

The full name of the LCD is Liquid Crystal Display.

LCD can not emit light by itself, it needs a light source from its backlight layer, the structure is shown in figure 3.

The liquid crystal (LC) is placed between two conductive glasses, when power is applied, the electric field is created between two electrodes.

In the electric field effect, the nematic liquid crystal molecules will twist, which can block the light passing through, to control the transmission or shielding of the light source from the backlight.

The degree of opening (twist) of LC is controlled by adjusting the voltage input. When the opening is large, more light can pass through. Therefore, the amount and brightness of the light are controllable.

After light passes through the color filter, red, green, and blue light is generated.

With the synthesis effect of light, color images are formed and displayed.

{Related article: “How does an LCD Work?”}

After the development of the last three decades, LCD technology is now relatively mature.

To adapt to various requirements in the market, different compensatory technologies keep introduced to the market, such as TFT and IPS.

III. OLED vs. LCD： What are the key differences in features?

With the knowledge of how both display technology work and their structures, the differences in features can be easy to explain.

For your quick knowledge, we have recapped the key differences in figure 5, then illustrate them in detail point by point.

(1) OLED vs. LCD: better anti-vibration and low-temperature resistance, but vulnerable to water damage

Compared with LCD, the OLED screen is a solid-state component, so it can perform better in anti-vibration and low-temperature resistance (normal low operation temperature is -40 ℃).

However, OLEDs are very sensitive to moisture and vulnerable to water damage.

(2) OLED vs. LCD: thinner, and foldable

As shown in the previous structure comparison, due to the existence of the backlight layer and liquid crystal layer, the LCD screen is thicker than the OLED.

For the same reason, the flexibility of LCD is limited, it can only be bent to a certain angle. The curved screens of the desktop are LCDs, which are only bent to a small degree.

In comparison, in addition to light and thin features, OLEDs can be folded almost as freely as origami. The foldable smartphone is supported by OLED technology.

(3) OLED vs. LCD: faster response, low image smear

It takes time for a pixel to change from color A to color B. This time is called the grayscale response time.

If the time takes too long, the pixel will not have time to change from color A to color B when the screen is rapidly sliding. As a result, the image remains and the image smear appears visually.

The high image persistence will significantly affect the visual perception and user experience.

Generally, the response time of LCD is 10ms, while OLED can achieve 0.001ms (1μs).

The OLED screen has almost no smear in normal usage except that the white text will produce the smear on a pure black background.

As to the LCD screen, normally it is hard to eliminate the smear, which is also affected by the temperature. The lower the temperature, the more serious the smear happens.

However, in 2022 SDI Display Week, Meta introduced their new generation VR headset Quest 2, which uses the fast switch LTPS LCD technology. The image persistence is low and almost not noticeable in VR game playing.

In conclusion, it is not an absolute winner as the technology development going ahead.

(4）OLED vs. LCD: higher contrast ratio

As the nature of the liquid crystal layer cannot be fully closed, when the LCD panel displays black, some light will pass through the color layer. The black shown on the LCD screen is gray, a combination of white and black.

Unlike LCD, when OLED displays black, the pixels in the black area can be directly turned off to achieve an almost pure black effect. In another word, In theory, OLEDs have an extreme contrast ratio. （shown in figure 6）

(5) OLED vs. LCD: wider viewing angle

The OLED is self-illuminating, and the viewing angle can be up to 170⁰.

Images on OLED will not be distorted from the sides and can maintain their quality and readability from nearly any angle. While the most common LCDs don’t.

LCD must block light when working, somehow there are natural observation obstacles in LCD.

You may notice when tilting or viewing an LCD monitor from different angles, images become distorted or lose their colors.

However, a new technology In-Plane Switching (IPS) has compensated for the drawback of LCD, the viewing angle of IPS LCD can even reach 170⁰.

{Related article: “Basics knowledge about LCD and TFT LCD you need to know”}

(6) OLED vs. LCD: lower power consumption

Each pixel of OLED work individually, the pixels turn off and consume no power at all when displaying black and consume different energy while displaying different colors in different brightness.

In contrast, no matter what color is displayed on the LCD, the backlight needs to be powered on.

This mean, in general usage, OLED saves more power than LCD.

(7) OLED vs. LCD: burn-in issue, shorter lifespan

However, the individual display character of OLED brings a natural flaw, a burn-in effect after long-time usage.

Because, in the terminal usage, the working frequency of each pixel for different colors is unequal, in consequence, the diminution rate is inconsistent.

In addition, the organic and self-emitting nature of OLED material is sensitive to humidity and oxygen concentration, resulting in some pixels degrading faster (decay period) than LCDs.

Therefore, the burn-in phenomenon inevitably happens on an OLED screen, more obviously on a big screen, and its average service lifespan is shorter than LCD.(shown in figure 8)

For example, on OLED TVs, burn-in happens on the blue pixels due to high frequent lighting. However, the white screen of OLED TVs will also change due to blue’s diminishing. If we compare the white screen every month, yellowish will be noticed.

(8) OLED vs. LCD: lower PPI

We know that pixels make up the screen, the more pixels on the same screen, the clearer the image shows.

However, due to the pixel arrangement of OLED, even if two screens have the same resolution, the clarity of the OLED screen will be lower than LCD.

So in the same resolution, the image shown on OLED is not as clear as on LCD.

For example, if the 1080p LCD screen is replaced with an OLED screen, it is obvious to see the graininesses on the screen. But when the resolution reaches above 2k, this phenomenon is not obvious anymore. (shown in figure 9)

(9) OLED vs. LCD: more expensive, popular in high-end devices

At present, given the technology developed more than 3 decades, LCD technology and supply chain is mature, and new technology and solution are still improving and introduced in the market to keep their advantage.

OLED technology is relatively new and in the developing stage, still has a long way to optimize the technology as well as the production processes and yield rate.

Even though the general cost of OLEDs is almost twice as much as LCD panels, OLED panels are still popular in high-end TVs or flagship mobile phones, while LCD panels have occupied the largest share in the whole display market.

IV. Common issues on OLED and LCD

Both display technology is not flawless, there still are visual problems insuperable.

(1）OLED: flickers appear in low brightness

In screen brightness control, for LCD, it is usual to control the brightness directly by adjusting the voltage of the backlight (DC dimming).

As in OLED, it is PWM (Pulse-Width Modulation) dimming, which means controlling the brightness by continuously switching on and off the screen at a certain high frequency till it is imperceptible by the naked eye.

In fact, in PWM dimming, the screen’s brightness is set and not changed. Instead, the lit time of the screen is changing, for example:

● If the screen brightness is 100%, means to keep the screen on for the whole period.

● If the brightness is 80%, the screen will be turned on 80% of the time, and off 20% of the time in a period.

● If the brightness is 50%, the screen will be turned on and off at the half time of the period.

Hence, in the low brightness status of the OLED, the screen off time is long, the black field interval become obvious, and the screen on and off (flickers) is noticeable by our naked eyes.

The flickers will easily cause discomfort and even dizziness to the eyes. （shown in figure 10）

（2）LCD: light leakage

Given the assembly structure of the backlight layer to the LCD panel, it is a gap between the screen and the frame to a certain degree.

Therefore, light leakage cannot be avoided in the current structure but only be controlled at a tolerance level.

V. OLED vs. LCD: Which is a better option for the eyes?

Both LCD and OLED screens emit a small amount of blue light.

Given the OLED screen is self-illuminating, when watching the screen in a dark environment, the light is strong, which causes more damage to the eyes than the light from LCD.

In addition to the flicker phenomenon, OLEDs will cause more obvious irritation to the eyes and even the migraine after a long-time of watching.

Therefore, in general, LCD screens are more eye-friendly than OLED screens.

VI. OLED vs. LCD: Which is better for your project?

When the question applies to the terminals’ application, the common answer is “it depends”.

Because in a project, except for the technology features, there are still many things that need to be considered, like budget, supply resources, etc.

Given the above analysis and our experience, we will recommend:

● LCDs: projects that require the most cost-effective solution and more flexibility in custom for the main control of the terminal, screen size almost covers all ranges.

● OLEDs: project with a high budget, and display terminal pursuing the best color display quality, thin and lightweight, better on a small screen.