Friends who work as display terminals have probably encountered such soul questioning:

The customer wants a 1000 nits high brightness screen, and the backlight LED has already been added to the top, so there are no more beads to fit in;

The PCB board heats up to the point of being hot to the touch, and the heat sink becomes thicker and thicker, resulting in excessive thickness of the entire machine;

The power consumption skyrocketed, and the battery life collapsed directly

The road of adding LED becomes narrower as we walk.

What can we do? In fact, there are already two mature technological paths in the industry:APF (Advanced Polarization Film) and DBEF (Dual Brightness Enhancement Film),All of them are schemes that recover light energy through reflection polarization.

They do not rely on "brute force" to add light beads, but on "ingenuity" to "snatch" light back from waste. Today's article will explain it thoroughly, and after reading it, you will know which project to choose.

1、 How is light wasted?

The light emitted by the backlight module of the LCD display screen is originally unpolarized light(Mixed light)It contains polarization components in various directions.

Only polarized light that is aligned with the transmission axis direction of the lower polarizer can be utilized by the liquid crystal panel, while polarized light that is orthogonal to it is basically directly absorbed when it reaches the polarizer.

That is to say, some of the light emitted by the backlight is not recognized by the LCD panel and was originally destined to be directly discarded by the polarizer.

What APF and DBEF do is to block the light before it is thrown away, reflect it back into the backlight cavity, and "redo it".

Some of the light that is reflected back has changed its polarization state inside the cavity, becoming light recognized by the panel and then transmitted out again.

It's like installing a light recycling bin for the backlight system, not wasting every beam of light, picking up the energy that should have been thrown away and reusing it.

The core principles of APF and DBEF are the same,The main difference lies in the installation method:

DBEFIt is an independent film inserted inside the backlight module

APFIt is directly attached to the LCD glass

2、 DBEF: Light recycling bin in backlight module

DBEF stands for Dual Brightness Enhancement Film, which is an independent reflective polarizing film,Placed inside the backlight module, usually above the light guide plate.

Its working mode is very direct: the light with the desired polarization state passes through directly, and the light with orthogonal polarization state reflects back into the backlight cavity and repeatedly "goes back to the furnace", with some of it returning to the desired polarization state and then transmitted out.

Industry tests have shown that DBEF can improve backlight efficiency by up tomore than 30%The specific gain depends on the backlight design and matching scheme, and the effect is better when stacked with BEF prism film.

More importantly, energy conservation.After adopting DBEF, the brightness can be significantly improved under the same power consumption, and the backlight power consumption can be significantly reduced under the same brightness.

For laptops and tabletsThis type of terminal, which is sensitive to battery life, means a solid selling point.

Typical application scenarios of DBEF: large displays, tablets, IoT devices, laptops.Taking DBEF-D200 as an example, with a thickness of only 200 μ m, it is particularly suitable for the LCD panel of high brightness laptops.

3、 APF: Advanced players directly pasted on glass

APF stands for Advanced Polarizing Film,The principle is the same as DBEF, which is reflective polarization. But the core difference lies in:APF is a reflective polarizing film directly laminated on LCD glass.

This brings several key differences:

① Thinner thickness

APF is directly attached to the LCD panel, which can partially replace the stacked structure of BEF/DBEF, simplify the optical architecture, and make the whole machine thinner and lighter. Taking APF-V3 as an example, the thickness is only 26 μ m.

② Better perspective performance

APF has better wide-angle brightness retention ability than DBEF, and the brightness attenuation is smaller when viewed off axis.

③ Higher environmental reliability

APF is directly attached to glass, with a more stable structure, lower thermal load, and better durability than independent reflective films. There is also a hard coating on the surface, which can resist scratches and pressure marks.

In terms of brightness gain, the technical specifications show that APF can achieve improved backlight efficiencyAbout 30%And the brightness remains better under a large viewing angle.

Typical application scenarios of APF: smartphones, tablets, laptops, VR headsets, IoT devices.If your project pursues extreme thinness, narrow borders, wide viewing angles, and high reliability, APF is the better solution.

Simple and crude conclusion

The project pursues high brightness and cost-effectiveness → on DBEF

DBEF is an independent membrane with moderate cost, and the brightness gain can usually reach over 30%. Combining with BEF yields better results. Suitable for large-sized displays and cost sensitive designs in traditional backlight structures.

The project pursues lightweight, narrow bezels, wide viewing angles, and high reliability → Go to APF

APF is directly attached to glass, with an extremely thin thickness, providing better viewing angle performance and reliability. Suitable for products such as smartphones, tablets, laptops, VR, etc. that pursue extreme thinness and narrow bezels.

Do you want both?

APF and DBEF can be combined and used according to specific needs, and combined with BEF and other films to achieve higher brightness gain.

The specific plan needs to be comprehensively evaluated based on the terminal scenario, thickness requirements, power consumption budget, and cost targets.

As a manufacturer of LCD display modules, we are very clear about:The same backlight power consumption, different optical schemes may result in twice the brightness difference.

We provide a full range of brightness enhancement solutions from APF to DBEF, and help you select the optimal solution based on your terminal scenario, thickness requirements, power budget, and cost goals.

We have mature mass production cases for laptop screens, display panels, car terminals, and various display devices.

Is the screen brightness insufficient? No need to add LED anymore, choose the right film and double the brightness. Welcome to send messages or leave messages to discuss your project requirements, and Saishida will customize an enhanced brightness solution for you.

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