LED Backlight on an IPS Panel But HOW??

[ChishtyNafi]

Yesterday I bought a lenovo monitor (L22i-30) which was an IPS panel. But on the packaging "LED Backlight" is written. I have always known that LCD and LED are two different technologies: and IPS is a LCD type monitor. So how come there be LED Backlight on an IPS pannel?

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[e22big]

LCD works by having a layer of liquid crystal with backlight shining through to create image - think of a colur spotlight, it's created coloured light by having a light source and a colour film for those light to go through. 

 

Those light sources are typically LED in most monitor, yes even LCD. It's how they get the panel to be so efficient and bright. You will unlikely to find a none-LED backlight on any LCD that wasn't made close to a decade ago. 

 

The LED LCD label is pretty dishonest and confusing in that aspect - it basically just mean ordinary LCD

[ChishtyNafi]

10 minutes ago, e22big said:

LCD works by having a layer of liquid crystal with backlight shining through to create image - think of a colur spotlight, it's created coloured light by having a light source and a colour film for those light to go through. 

 

Those light sources are typically LED in most monitor, yes even LCD. It's how they get the panel to be so efficient and bright. You will unlikely to find a none-LED backlight on any LCD that wasn't made close to a decade ago. 

 

The LED LCD label is pretty dishonest and confusing in that aspect - it basically just mean ordinary LCD

Previously I used a samsung va panel monitor (Samsung C22F390FHW 21.5''). And my current monitor is an IPS panel. But surprisingly the viewing angle of that VA panel was better than this IPS panel. Even the color reproduction looked better to me. How is that even possible?

[mariushm]

LCD panel is basically a panel of  square cells  which can be transparent or semi-transparent or fully opaque depending on the amount of current flowing through the liquid inside the cell. TN, IPS, VA refers to different technologies, that deal how the liquid crystals inside twists/rearranges to become as transparent as possible or as opaque as possible. 

 

Each type has pluses and minuses ... there's compromises.

 

TN is super fast, so you can make monitors with very high frame rates, but the view angles are bad (as you move your head towards the sides of the monitor, the colors shift a bit)

VA is very good at blocking the light, is very opaque, so that means you get very good contrast, darker blacks, and suffers much less from color shifting as you move your head from the "straight in front of you" direction,  but it's SLOW, so it's harder to make monitors with high framerate using VA lcd. 

IPS is faster than VA and have very good view angles but it's a bit worse at contrast (don't get as deep blacks as with VA) and IPS panels often have a characteristic "glow" that can be noticeable in very dark rooms. 

 

On top of these cells you have the color filters (red, green and blue)  then you have light going through the lcd panel and the color filters to form pixels. 

 

The light is white or it could even be blue for higher efficiency, and the color filters change it to read , green and blue..  

 

So basically there's thin strips of leds on the edges of the monitor producing light ... then there's a bunch of filters which spread the light as uniformly as possible across the whole panel and change its direction so it comes out the panel. 

Some monitors have leds all across the back of the panel instead of the edges, you see this more often in HDR monitors, because that's how it's possible to have multiple regions (for example the whole panel surface is virtually split into 96 rectangles and each rectangle's brightness can be adjusted independently, allowing for the panel to increase the brightness in that region as needed for HDR, without increasing the brightness in other places. it also allows to save power and make cheap HDR monitors, because you can have 96 regions that could each consume  up to 10w of power and be super bright, but ship the monitor with a 300w power supply, because you'll never allow all 96 regions to consume 10w, or almost 1000 watts) 

 

In the past we also had CCFL for backlight, or cold cathode fluorescent light ... instead of tiny leds on the edges, think thin long tubes of neon 

 

You can see both technologies in the video below if you're curious: 

 

 

[jaslion]

45 minutes ago, ChishtyNafi said:

Previously I used a samsung va panel monitor (Samsung C22F390FHW 21.5''). And my current monitor is an IPS panel. But surprisingly the viewing angle of that VA panel was better than this IPS panel. Even the color reproduction looked better to me. How is that even possible?

Ips isnt magical. Its just a different kind of lcd. There are plenty craptastic ips panel

[e22big]

1 hour ago, ChishtyNafi said:

Previously I used a samsung va panel monitor (Samsung C22F390FHW 21.5''). And my current monitor is an IPS panel. But surprisingly the viewing angle of that VA panel was better than this IPS panel. Even the color reproduction looked better to me. How is that even possible?

 

Every panels are differnet. Even TN have some model with great viewing angle and likewise, there's IPS with poor viewing angle, especially for the lower end products. While it's true that as a rule, IPS tends to have a much better viewing angle than VA but that's not always a given. 

[Stahlmann]

IPS, TN and VA all are LCD backlit panels. They all need a backlight because the pixels themselves don't produce any light. The only current consumer display tech that doesn't use a backlight is OLED because every pixel can produce it's own light.

[mariushm]

Just now, Stahlmann said:

IPS, TN and VA all are LCD backlit panels. They all need a backlight because the pixels themselves don't produce any light. The only current consumer display tech that doesn't use a backlight is OLED because every pixel can produce it's own light.

Transflective LCDs don't have backlight, they rely on light reflected off them. They're used for smaller size displays, for calculators, watches. This stuff doesn't work well for lots of colors,  backlight is better..

Also, while not actual lcd monitor,  eInk displays also don't have backlight ... it's pigments in the material being moved to create dots