Display types: Difference between revisions

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==Backlit flat-panel displays==
==Backlit flat-panel displays==
<!--
<!--
We may call them LCD, but that was an early generation
LCD and TFT and various other acronyms are all the same idea, with different refinements on how the pixels work exactly.
LCD and TFT and various other acronyms are all the same idea, with different refinements on how the pixels work exactly.
There are roughly two parts of such monitors you can care about: How the backlight works, and how the pixels work.


But almost all of them come down to
But almost all of them come down to
* put bright lights on the side of the screen and put effort into making that an even backlight evenly
* pixels will block light, or less so.
* put a bright lights behind those
: in practice, they are on the side, and there is some trickery to try to reflect that as uniformly as possible
 
 
There are a lot of acronyms pointing tou
: TN and IPS is more about the crystals (and you mostly care about that if you care about viewing angle),
: TFT is more about the electronics, but the two aren't really separable,
: and then there are a lot of experiments (with their own acronyms) that  


* pixels block or don't block light
https://en.wikipedia.org/wiki/TFT_LCD
-->


There are roughly two parts of such monitors you can care about: How the backlight works, and how the pixels work.
TFT, UFB, TFD, STN


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https://nl.wikipedia.org/wiki/CCFL
https://nl.wikipedia.org/wiki/CCFL


===LCD/TFT/similar===
==Self-lit==
 
===OLED===
<!--
<!--


TFT, UFB, TFD, STN
While OLED is also a thing in lighting, OLED ''usually'' comes up in the context of OLED displays.
-->
 
It is mainly contrasted with backlit displays (because it is hard to get those to block all light).
OLEDs being off just emit no light at all. So the blacks are blacker, you could go brighter at the same time,
There are some other technical details why they tend to look a little crisper.


==Self-lit==
Viewing angles are also better, ''roughly'' because the light source is closer to the surface.


===OLED===
<!--


OLED are organic LEDs, which in itself party just a practical production detail, but really just LEDs.
OLED are organic LEDs, which in itself party just a practical production detail, and really just LEDs.
(...though you can get fancy in the production process, e.g. see-through display may be OLED with substate trickery{{verify}})
{{comment|(...though you can get fancy in the production process, e.g. pricy see-through displays are often OLED with substate trickery{{verify}})}}




While OLED is also a thing in lighting, OLED ''usually'' comes up in the context of OLED displays,
a variant of monitors where the display pixels themself emits light,
rather than a backlight (most monitors are still backlit, which previously were side-lit with CCFL, and now commonly side-lit with LED).


One of the largest upsides of such monitors is that you can get a pixel that produces no no light,  
PMOLED versus AMOLED makes no difference to the light emission,  
in contrast with older screens that would block the backlight, but only ''mostly'' manage that.
just to the way we access them, but it can mean lower power, higher speed, and more options along that scale{{verify}},
So the blacks are blacker. There are some other details why they tend to look crisper.
all of which makes them interesting for mobile uses. It also scales better to larger monitors.


POLED (and confusingly, pOLED is a trademark) uses a polymer instead of the glass,
so is less likely to break but has other potential issues


Viewing angles are also better, ''roughly'' because the light source is closer to the surface.




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'''Confusion'''
'''Confusion'''


"Phones use OLED"


Fancier, pricier ones do, yes.
"Isn't LED screen the same as OLED?"
Cheaper ones do not, because the display alone will be a hundred bucks.{{verify}}


No.
Marketers will be happy if you confuse "we used a LED backlight instead of a CCFL" (which we've been doing for ''ages'')
with "one of those new hip crisp OLED thingies", while not technically lying,
so they may be fuzzy about what they mean with "LED display".


"Doesn't LED screen mean OLED?"
You'll know when you have an OLED monitor, because it will cost ten times as much - a thousand USD/EUR, more at TV sizes.
The cost-benefit for people without a bunch of disposable income isn't really there.


No. "LED display" means LEDs were involved somehow. It can easily mean "we used a LED backlight instead of a CCFL" -- and the days, almost all LCD monitors are LED in this sense.


Marketing people ''really don't mind'' if you assume it's the same thing as OLED.


You'll know when you have OLED, because it will cost ten times as much - two thousand USD/EUR, more at TV sizes.
"I heard al phones use OLED now?"
The cost-benefit for the non-rich isn't there.


Fancier, pricier ones do, yes.
Cheaper ones do not, because the display alone might cost on the order of a hundred bucks.{{verify}}


[[Image:OLED.jpg|thumb|300px|right|Monochrome OLED]]
[[Image:Not OLED.jpg|thumb|400px|right|Not OLED (clearly backlit)]]
Also, while there are small, often-monochrome OLED (or PLED) displays, the the ebays and aliexpresses sellers of the world will happily call any small screen OLED if it means they sell more.




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===QLED===
===QLED===
<!--
<!--
It's quantum, so it's buzzword compatible.  
It's quantum, so it's buzzword compatible. How is it quantum? Who knows!
 
How is it quantum? Who knows!




It's brighter, but they're still working on details like decent contrast.
It may surprise you that this is LCD-style, not OLED-style,
but is brighter than most LCD style,


they're still working on details like decent contrast.




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-->
-->


===Matrix dislays===
===Matrix displays===
 
 
===(near-)monochrome===
 
 
====SSD1306====


OLED, 128x64@4 colors{{vierfy}}


https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf


====SH1107====
OLED,
https://datasheetspdf.com/pdf-file/1481276/SINOWEALTH/SH1107/1


===Small LCD/TFTs / OLEDs===
===Small LCD/TFTs / OLEDs===
{{stub}}
{{stub}}


Small as in order of an inch.
Small as in order of an inch or two (because the controllers are designed for a limited resolution?{{verify}}).




{{zzz|Note that, like with monitors, marketers really don't mind if you confuse backlit LCD with OLED,
and some of the ebays and aliexpresses sellers of the world will happily 'accidentally'
call any small screen OLED if it means they sell more.


One ones with more colors are often '''backlit LCD style''' {{comment|(and them sometimes incorrectly referred to OLED. When buying off ebay and aliexpress, maybe double check the specs)}}
This is further made more confusing by the fact that there are
* few-color OLEDs (2 to 8 colors or so, great for high contrast but ''only'' high cotnrast),
* [[high color]] OLEDs (65K),
...so you sometimes need to dig into the tech specs to see the difference between high color LCD and high color OLED.
}}


<!--
[[Image:OLED.jpg|thumb|300px|right|Monochrome OLED]]
[[Image:OLED.jpg|thumb|300px|right|High color OLED]]
[[Image:Not OLED.jpg|thumb|400px|right|Not OLED (clearly backlit)]]
-->


There are also '''OLED style''' displays.
Many cheap OLEDs are single-color, and no shades, so while they are high contrast, they are ''only'' high contrast.


When all pixels are off they give zero light pollution (unlike most LCDs) which might be nice in the dark.
When all pixels are off they give zero light pollution (unlike most LCDs) which might be nice in the dark.
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'''Video or not?'''
'''Can it do video or not?'''


These often don't connect video cables, but have their own controller.
If it ''does'' speak e.g. MIPI it's basically just a monitor, probably capable of decent-speed updates, but also the things you ''can'' connect to will (on the scale of microcontroller to mini-PC) be moderately powerful, e.g. a raspberry.


Displaying video on them is doable on some, but more finicky to do.
But the list below don't connect PC video cables.  


The SPI interface should work anywhere, but is more limited in what it can do and how fast it can do it.
Still, they have their own controller, and can hold their pixel state one way or the other, but connect something more command-like - so you can update a moderate amount of pixels with via an interface that is much less speedy or complex.


Note that features are a precarous balance, in the sense that if it ''does'' speak MIPI it's basically just a monitor,
You might get reasonable results over SPI / I2C for a lot of e.g. basic interfaces and guages.
but you need something with the controller (though having a controller-side framebuffer is easily a few hundred kilobytes).
By the time you try to display video you have to think about your design more.
If it speaks something similar, you might need to bit bang it, and  
doing that at the speeds required for something you might call ''video'' will be a challenge from a lot of hardware.


For a large part because amount of pixels to update times the rate of frames per second has to fit through the communication (...also the display's capabilities).
There is a semi-standard parallel interface that might make video-speed things feasible.
This interface is faster than the SPI/I2C option, though not always ''that'' much, depending on hardware details.


That said, something like the {{imagesearch|tinycircuits tinytv|TinyTV}} runs a 216x135 65Kcolor display from a from a [[RP2040]], with specifically converted video.


Even if the specs of the screen can do it in theory, you also have to have the video ready to send.
If you're running it from an RP2040 or ESP32, don't expect to libav/ffmpeg.
Say, something like the {{imagesearch|tinycircuits tinytv|TinyTV}} runs a 216x135 65Kcolor display from a from a [[RP2040]].
Also note that such hardware won't be doing decoding and rescaling arbitrary video files.
They will use specifically pre-converted video.
In your choices, also consider libraries.
Things like [https://github.com/Bodmer/TFT_eSPI TFT_eSPI] has a compatibility list you will care about.
====Interfaces====
{{stub}}
<!--
* 4-line SPI
* 3-line SPI ([[half duplex]], basically)
* I2C
* 6800-series parallel
* 8080-series parallel interface
The last two are 8-bit parallel interfaces. ''In theory'' these can be multiples faster,
though notice that in some practice you are instead limited by the display's controller,
your own ability to speak out data that fast, and the difference may not even be twice
(and note that [[bit-banging]] that parallel may take a lot more CPU than dedicated SPI would).
The numbers aren't about capability, they seem to purely references then Intel versus Motorola origins of their specs{{verify}})
They are apparently very similar - the main differences being the read/write and enable, and in some timing.
: If they support both, 8080 seems preferable, in part because some only support that?{{verify}}
There are others that aren't quite ''generic'' high speed moniutor interfaces yet,
but too fast for slower hardware (e.g. CSI, MDDI)
https://forum.arduino.cc/t/is-arduino-6800-series-or-8080-series/201241/2
-->


====ST7735====
====ST7735====
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====HX8352C====
====HX8352C====
LCD
<!--
240(RGB)x480, 16-bit
-->
https://www.ramtex.dk/display-controller-driver/rgb/hx8352.htm
https://www.ramtex.dk/display-controller-driver/rgb/hx8352.htm


====HX8357C====
====R61581====
<!--
240x320
-->


====ILI9163====
====ILI9163====
LCD
LCD, 162x132@16-bit RGB


http://www.hpinfotech.ro/ILI9163.pdf
http://www.hpinfotech.ro/ILI9163.pdf


====ILI9341====
====ILI9341====
<!--
240RGBx320, 16-bit
-->
https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf
https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf


====ILI9486====
====ILI9486====
LCD  
LCD, 480x320@16-bit RGB


https://www.hpinfotech.ro/ILI9486.pdf
https://www.hpinfotech.ro/ILI9486.pdf
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====ILI9488====
====ILI9488====
LCD  
LCD  
<!--
320(RGB) x 480
-->


https://www.hpinfotech.ro/ILI9488.pdf
https://www.hpinfotech.ro/ILI9488.pdf


====PCF8833====
====PCF8833====
LCD
LCD, 132×132 16-bit RGB


https://www.olimex.com/Products/Modules/LCD/MOD-LCD6610/resources/PCF8833.pdf
https://www.olimex.com/Products/Modules/LCD/MOD-LCD6610/resources/PCF8833.pdf
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https://vfdclock.jimdofree.com/app/download/7279155568/SEPS225.pdf
https://vfdclock.jimdofree.com/app/download/7279155568/SEPS225.pdf


===(near-)monochrome===


====RM68140====
LCD
<!--
320 RGB x 480
-->


====SSD1306====
https://www.melt.com.ru/docs/RM68140_datasheet_V0.3_20120605.pdf
 
OLED
 
https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
 
====SH1107====
 
OLED,
 
https://datasheetspdf.com/pdf-file/1481276/SINOWEALTH/SH1107/1


===Round===
====GC9A01 (round)====
====GC9A01====


backlit LCD, 65K colors, SPI
LCD, 65K colors, SPI


https://www.buydisplay.com/download/ic/GC9A01A.pdf
https://www.buydisplay.com/download/ic/GC9A01A.pdf

Revision as of 19:42, 24 March 2024

Backlit flat-panel displays

CCFL or LED backlight

https://nl.wikipedia.org/wiki/CCFL

Self-lit

OLED

QLED

On image persistence / burn-in

VFD

  • larger segments

    larger segments

  • dot matrix VFD

    dot matrix VFD

Vacuum Fluorescent Displays are vacuum tubes applied in a specific way - see Lightbulb_notes#VFDs for more details.


Lighting

Nixie tubes


Mechanical

Mechanical counter

https://en.wikipedia.org/wiki/Mechanical_counter

Split-flap

https://en.wikipedia.org/wiki/Split-flap_display


LED segments

7-segment and others

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.
7-segment, 9-segment display, 14-segment, and 16-segment display. If meant for numbers will be a dot next to each (also common in general), if meant for time there will be a colon in one position.


These are really just separate lights that happen to be arranged in a useful shape.

Very typically LEDs (with a common cathode or anode), though similar ideas are sometimes implemented in other display types - notably the electromechanical one, also sometimes VFD.


Even the simplest, 7-segment LED involves a bunch of connectors so are

  • often driven multiplexed, so only one of them is on at a time.
  • often done via a controller that handles that multiplexing for you


Seven segments are the minimal and classical case, good enough to display numbers and so e.g. times, but not really for characters.

More-than-7-segment displays are preferred for that.


https://en.wikipedia.org/wiki/Seven-segment_display

DIY

LCD character dislays

Character displays are basically those with predefined (and occasionally rewritable) fonts.


Classical interface

The more barebones interface is often a 16 pin line with a pinout like

  • Ground
  • Vcc
  • Contrast
usually there's a (trim)pot from Vcc, or a resistor if it's fixed


  • RS: Register Select (character or instruction)
in instruction mode, it receives commands like 'clear display', 'move cursor',
in character mode,
  • RW: Read/Write
tied to ground is write, which is usually the only thing you do
  • ENable / clk (for writing)
  • 8 data lines, but you can do most things over 4 of them


  • backlight Vcc
  • Backlight gnd


The minimal, write-only setup is:

  • tie RW to ground
  • connect RS, EN, D7, D6, D5, and D4 to digital outs


I2C and other

Matrix displays

(near-)monochrome

SSD1306

OLED, 128x64@4 colorsTemplate:Vierfy

https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf

SH1107

OLED,

https://datasheetspdf.com/pdf-file/1481276/SINOWEALTH/SH1107/1

Small LCD/TFTs / OLEDs

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.

Small as in order of an inch or two (because the controllers are designed for a limited resolution?(verify)).


💤 Note that, like with monitors, marketers really don't mind if you confuse backlit LCD with OLED,

and some of the ebays and aliexpresses sellers of the world will happily 'accidentally' call any small screen OLED if it means they sell more.

This is further made more confusing by the fact that there are

  • few-color OLEDs (2 to 8 colors or so, great for high contrast but only high cotnrast),
  • high color OLEDs (65K),

...so you sometimes need to dig into the tech specs to see the difference between high color LCD and high color OLED.



When all pixels are off they give zero light pollution (unlike most LCDs) which might be nice in the dark. These seem to appear in smaller sizes than small LCDs, so are great as compact indicators.


Can it do video or not?

If it does speak e.g. MIPI it's basically just a monitor, probably capable of decent-speed updates, but also the things you can connect to will (on the scale of microcontroller to mini-PC) be moderately powerful, e.g. a raspberry.

But the list below don't connect PC video cables.

Still, they have their own controller, and can hold their pixel state one way or the other, but connect something more command-like - so you can update a moderate amount of pixels with via an interface that is much less speedy or complex.

You might get reasonable results over SPI / I2C for a lot of e.g. basic interfaces and guages. By the time you try to display video you have to think about your design more.

For a large part because amount of pixels to update times the rate of frames per second has to fit through the communication (...also the display's capabilities). There is a semi-standard parallel interface that might make video-speed things feasible. This interface is faster than the SPI/I2C option, though not always that much, depending on hardware details.


Even if the specs of the screen can do it in theory, you also have to have the video ready to send. If you're running it from an RP2040 or ESP32, don't expect to libav/ffmpeg.

Say, something like the TinyTV runs a 216x135 65Kcolor display from a from a RP2040.

Also note that such hardware won't be doing decoding and rescaling arbitrary video files. They will use specifically pre-converted video.


In your choices, also consider libraries. Things like TFT_eSPI has a compatibility list you will care about.



Interfaces

✎ This article/section is a stub — some half-sorted notes, not necessarily checked, not necessarily correct. Feel free to ignore, or tell me about it.


ST7735

LCD, 132x162@16bits RGB


ST7789

LCD, 240x320@16bits RGB

https://www.waveshare.com/w/upload/a/ae/ST7789_Datasheet.pdf

SSD1331

OLED, 16bits RGB https://cdn-shop.adafruit.com/datasheets/SSD1331_1.2.pdf

SSD1351

OLED, 65K color

https://newhavendisplay.com/content/app_notes/SSD1351.pdf

HX8352C

LCD https://www.ramtex.dk/display-controller-driver/rgb/hx8352.htm


HX8357C

R61581

ILI9163

LCD, 162x132@16-bit RGB

http://www.hpinfotech.ro/ILI9163.pdf

ILI9341

https://cdn-shop.adafruit.com/datasheets/ILI9341.pdf

ILI9486

LCD, 480x320@16-bit RGB

https://www.hpinfotech.ro/ILI9486.pdf

ILI9488

LCD

https://www.hpinfotech.ro/ILI9488.pdf

PCF8833

LCD, 132×132 16-bit RGB

https://www.olimex.com/Products/Modules/LCD/MOD-LCD6610/resources/PCF8833.pdf

SEPS225

LCD

https://vfdclock.jimdofree.com/app/download/7279155568/SEPS225.pdf


RM68140

LCD

https://www.melt.com.ru/docs/RM68140_datasheet_V0.3_20120605.pdf

GC9A01 (round)

LCD, 65K colors, SPI

https://www.buydisplay.com/download/ic/GC9A01A.pdf

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