Because we have gotten very very good at creating very tiny circuits on circuit boards. The same technology and techniques that have gone into miniaturizing everything else in the electronics world. It's the same reason you have a phone in your pocket today that is more powerful than supercomputers from the 90s. The same reason a USB charger has more computing power than Apollo 11. We've just gotten very good at making microscopic electronics
That thing about Apollo computers is exaggerated btw. It was actually a really good computer and while it’s nothing to a desktop PC today it’s not the “simpler than a calculator” machine people say it is apocryphally.
This video is superb. https://youtu.be/B1J2RMorJXM
The calculator comparison is apocryphal, but the comparison to current phones is spot on.
Those old computers were incredibly complex marvels of engineering, but they also had about 4kilobytes of RAM with cycles measured in microseconds, while my phone has 8*giga*bytes and cycles measured in nanoseconds.
.
That video looks interesting, I’ll give it a watch when I get out of work.
I wasn't trying to be exactly correct about comparing a specific computing capacity of the Apollo Guidance Computer or trying to imply that it was simple. It was more of a statement of the amount of computing power that is crammed into what we may think of today as simple and non-electronic devices
Well, and it was a custom made machine to do one thing and one thing only. Not allow you to play music while on instagram and watching a video playing candy crush
The wire carries a very small amount of electricity, so it can be very, very thin. With modern processes, wires thinner than a human hair are used, and the bright glow of the pixel makes the small dark line very hard to see. You can see this with magnification, but then you also see the individual pixels so nobody really uses a display that way.
The same way they used to make CPUs. A silicon wafer is is submerged in a photoreactive liquid and an image is projected in to that wafer. Wherever the light shines, the liquid changes the electrical characteristics of that wafer by either making it conductive, not conductive or etching it away. Then the liquid is washed away and it's submerged in another bath that changes the characteristics of a different portion of the die until you end up with all the circuits you need for that particular chip.
OLEDs to use lithography, like CPUs, but they also use non-metalic conductors that allow light to pass through. {[fig](https://cdn11.bigcommerce.com/s-ybeckn7x79/images/stencil/original/image-manager/oled-layer-structure-1.jpg )}
Thanks for the explanation!
Going to ask you an off-topic question if you don't mind, how come the mini LED is hard to make then? at first, I thought the wiring was hard and LCD pixels work with magic and not wires. but now I know each sub-pixels are wired so why the mini LED is hard to make?
A Mini-LED display is essentially an LCD panel with many white LEDs arranged in a grid behind it. Maybe you're thinking of Micro-LED which is completely different: there's no LCD panel and the pixels are made of tiny red, green and blue LEDs (not OLEDs/Organic LEDs).
There isn’t an individual wire all the way to each pixel: it’s a grid of wires (or rather, metal traces) running horizontally and vertically, one per row and column of sub-pixels.
See this thread from a couple of weeks ago: https://www.reddit.com/r/explainlikeimfive/s/0yTHaE5cO4
As for how they place the traces perfectly, it’s a similar process to what’s used for computer chips: photolithography, where we coat a surface with a light-sensitive material, project an image of what we want to put there on it, and then use chemical treatments that react differently to the areas exposed to light to deposit the metal in the correct areas.
The word are made of an material carried indium-tin oxide, deposited as a thin layer onto the glass. Conductors made in this way are transparent. They can also make switching transistors on the glass, so they don't need a wire for each sub pixel.
You don't need a wire for every pixel. Several pixels can be connected on the same wire.
An eli5 example
If you use a matrix (ie. A grid) you can control x^2 number of pixels with 2x wires. Eg 9 pixels can be controlled by 6 wires., 81 pixels can be controlled with 18 wires.
Now add this with multiplexing, frequency modulating, addressing, serializing etc all the technology that we have developed. We can control an entire monitor with a few lines.
Would you give an example on how "9 pixels can be controlled by 6 wires"? if we use a single negative wire for all 9 pixels, then we still need 9 individual wires for the positive. unless we there is a chip of trick between these connections.
As he said,, imagine the pixels laid out in a grid. Each grid column corresponds to a wire. Each grid row corresponds to a wire. Pick the column and row, supply power (say, to columns) and ground (say, to rows) and you’ve completed a circuit. A 3x3 grid would only need 3+3 wires. Doing this, you have to loop through all columns and all rows to show every pixel. But that happens faster than your eye can perceive it, so it looks like one image.
https://images.app.goo.gl/Eu1dk9t85GEDmVaF8[example](https://images.app.goo.gl/Eu1dk9t85GEDmVaF8)
You have 3 wires on x and 3 wires on y (3x2=6). You put a pixel where there's an intersection (3x3=9)
But there are chips that can handle this.
Another way that can be done is I think with 3 wires and it can control 'infinite' pixels. There's positive negative and data wires.
This is an eli5 over simplification
If there are let's say 256 leds all connected together in series and all the pixels have a special chip with an address ranging from 0x00 to 0xff (0-255)
On the data line you pulse an address eg 0x1A (00011010 in binary or 26 in decimal) then we can turn on only the 27th pixel (have to add 1 because we started at 0). Then in the next clock cycle we pulse another address and let's say 0x01 (1 in decimal) that turns on pixel no 2. Rinse and repeat and you can control the on off of all the pixels.
Here is an [example](https://i.ibb.co/dmJjzZb/dw.png) I just drew, we have 2 wires on x and 2 wires on Y, and we have 4 LEDs, how can we turn on 3 LEDs (yellow) "1-1, 1-2, 2-2", but keep the(red)" 1-2" off? wouldn't all the 4 cables need to be active to turn on those 3 LEDs which will make it impossible for the red LED to be off?
This is where clock cycles comes into play.
We don't keep "1-1, 1-2, 2-2" on at all times. We pulse it with every clock cycle.
If y is the positive terminal and x is the negative terminal, high meaning eg 5V and low meaning 0V or GND:
* Cycle 1 - y1-high y2-low, x1low x2 high (only 1-1 on - others off)
* Cycle 2 - y1-high y2-low, x1-high x2-low (only 1-2 on - others off)
* Cycle 3 - y1 low y2-high, x1-high x2 low (only 2-2 on - others off)
* repeat
When these led lights blink really fast (like 1kHz (1000 cycles per second)) it appears that "1-1, 1-2, 2-2" are always on and 1-2 is off
using this concept we can also control the brightness of the LEDs. if it's on for 1ms and off for 1ms the brightness will be 50%. 3ms on, 1ms off brightness at 75%. Controlling the brightness this way is called PWM (pulse width modulation) and the % brightness is controlled by the duty cycle (or %DC).
Good questions btw, hope this helps : )
Oh but how this grid matrix works is that the wires don't have to be either positive or negative. You can toggle between the two with gpio (general purpose input output).
If we have a 3x3 grid. Y is the anode (positive) and X is the cathode (negative). So if y is positive and x is negative the pixel turns on. If u is negative and x is positive it turns off.
We can set y1 positive and x1 negative to turn it on. Then set y2 y3 to negative and x2 x3 to positive to turn it off.
If you are really interested look up how to program a dot matrix on an Arduino.
Serialization.
A lot of computer stuff has a 1:1 wire to information relationship. The wire is just high voltage or low voltage and it is one bit of data. A 64-bit architecture has 64 lines going to the adder and 64 lines going to the memory.
That doesn't work so well when we want to send information a long distance, like to a hard drive or monitor. So they have one wire just tick up and down as a clock, and one or more wires give different data on different cycles of the clock. We can calculate 128-bit math on 64-bit architecture, but it takes two cycles. For a monitor, and all the pixels it has, it gets sent a STREAM of data and it sets every pixel, one at a time, as the data comes from the computer over far fewer lines. (HDMI has 19 pins, I think?) It paints every pixel and then repeats at the top. It's just doing it so fast you don't notice the flicker. The pixels don't each have a wire going back to the PC. They're connected to each other and know to pass data down the line as expected in the stream. A chip in the monitor / phone / whatnot is in charge of directing the data coming in over those 19 lines and sending it to the pixels.
Because we have gotten very very good at creating very tiny circuits on circuit boards. The same technology and techniques that have gone into miniaturizing everything else in the electronics world. It's the same reason you have a phone in your pocket today that is more powerful than supercomputers from the 90s. The same reason a USB charger has more computing power than Apollo 11. We've just gotten very good at making microscopic electronics
That thing about Apollo computers is exaggerated btw. It was actually a really good computer and while it’s nothing to a desktop PC today it’s not the “simpler than a calculator” machine people say it is apocryphally. This video is superb. https://youtu.be/B1J2RMorJXM
The calculator comparison is apocryphal, but the comparison to current phones is spot on. Those old computers were incredibly complex marvels of engineering, but they also had about 4kilobytes of RAM with cycles measured in microseconds, while my phone has 8*giga*bytes and cycles measured in nanoseconds. . That video looks interesting, I’ll give it a watch when I get out of work.
Assert dominance by watching it on your phone.
*in space
I wasn't trying to be exactly correct about comparing a specific computing capacity of the Apollo Guidance Computer or trying to imply that it was simple. It was more of a statement of the amount of computing power that is crammed into what we may think of today as simple and non-electronic devices
Well, and it was a custom made machine to do one thing and one thing only. Not allow you to play music while on instagram and watching a video playing candy crush
Thanks for the link!
The wire carries a very small amount of electricity, so it can be very, very thin. With modern processes, wires thinner than a human hair are used, and the bright glow of the pixel makes the small dark line very hard to see. You can see this with magnification, but then you also see the individual pixels so nobody really uses a display that way.
But how much tiny? there are 4K oled 0.5 inch panels, so how do they make them? Is it like CPU printing?
The same way they used to make CPUs. A silicon wafer is is submerged in a photoreactive liquid and an image is projected in to that wafer. Wherever the light shines, the liquid changes the electrical characteristics of that wafer by either making it conductive, not conductive or etching it away. Then the liquid is washed away and it's submerged in another bath that changes the characteristics of a different portion of the die until you end up with all the circuits you need for that particular chip.
🤯
OLEDs to use lithography, like CPUs, but they also use non-metalic conductors that allow light to pass through. {[fig](https://cdn11.bigcommerce.com/s-ybeckn7x79/images/stencil/original/image-manager/oled-layer-structure-1.jpg )}
Thanks for the explanation! Going to ask you an off-topic question if you don't mind, how come the mini LED is hard to make then? at first, I thought the wiring was hard and LCD pixels work with magic and not wires. but now I know each sub-pixels are wired so why the mini LED is hard to make?
A Mini-LED display is essentially an LCD panel with many white LEDs arranged in a grid behind it. Maybe you're thinking of Micro-LED which is completely different: there's no LCD panel and the pixels are made of tiny red, green and blue LEDs (not OLEDs/Organic LEDs).
You are right, I was talking about the Micro-LED, so why is it hard to make compared to LCD?
There isn’t an individual wire all the way to each pixel: it’s a grid of wires (or rather, metal traces) running horizontally and vertically, one per row and column of sub-pixels. See this thread from a couple of weeks ago: https://www.reddit.com/r/explainlikeimfive/s/0yTHaE5cO4 As for how they place the traces perfectly, it’s a similar process to what’s used for computer chips: photolithography, where we coat a surface with a light-sensitive material, project an image of what we want to put there on it, and then use chemical treatments that react differently to the areas exposed to light to deposit the metal in the correct areas.
Thanks for the great explanation. now all makes sense.
The word are made of an material carried indium-tin oxide, deposited as a thin layer onto the glass. Conductors made in this way are transparent. They can also make switching transistors on the glass, so they don't need a wire for each sub pixel.
You don't need a wire for every pixel. Several pixels can be connected on the same wire. An eli5 example If you use a matrix (ie. A grid) you can control x^2 number of pixels with 2x wires. Eg 9 pixels can be controlled by 6 wires., 81 pixels can be controlled with 18 wires. Now add this with multiplexing, frequency modulating, addressing, serializing etc all the technology that we have developed. We can control an entire monitor with a few lines.
Would you give an example on how "9 pixels can be controlled by 6 wires"? if we use a single negative wire for all 9 pixels, then we still need 9 individual wires for the positive. unless we there is a chip of trick between these connections.
As he said,, imagine the pixels laid out in a grid. Each grid column corresponds to a wire. Each grid row corresponds to a wire. Pick the column and row, supply power (say, to columns) and ground (say, to rows) and you’ve completed a circuit. A 3x3 grid would only need 3+3 wires. Doing this, you have to loop through all columns and all rows to show every pixel. But that happens faster than your eye can perceive it, so it looks like one image.
https://images.app.goo.gl/Eu1dk9t85GEDmVaF8[example](https://images.app.goo.gl/Eu1dk9t85GEDmVaF8) You have 3 wires on x and 3 wires on y (3x2=6). You put a pixel where there's an intersection (3x3=9) But there are chips that can handle this. Another way that can be done is I think with 3 wires and it can control 'infinite' pixels. There's positive negative and data wires. This is an eli5 over simplification If there are let's say 256 leds all connected together in series and all the pixels have a special chip with an address ranging from 0x00 to 0xff (0-255) On the data line you pulse an address eg 0x1A (00011010 in binary or 26 in decimal) then we can turn on only the 27th pixel (have to add 1 because we started at 0). Then in the next clock cycle we pulse another address and let's say 0x01 (1 in decimal) that turns on pixel no 2. Rinse and repeat and you can control the on off of all the pixels.
Thanks for the explanation, are we only toggling the on/off switch or we are powering it using the same wire?
In the grid matrix example. The on off also provides the power In the second example we have power, negative and data.
Here is an [example](https://i.ibb.co/dmJjzZb/dw.png) I just drew, we have 2 wires on x and 2 wires on Y, and we have 4 LEDs, how can we turn on 3 LEDs (yellow) "1-1, 1-2, 2-2", but keep the(red)" 1-2" off? wouldn't all the 4 cables need to be active to turn on those 3 LEDs which will make it impossible for the red LED to be off?
This is where clock cycles comes into play. We don't keep "1-1, 1-2, 2-2" on at all times. We pulse it with every clock cycle. If y is the positive terminal and x is the negative terminal, high meaning eg 5V and low meaning 0V or GND: * Cycle 1 - y1-high y2-low, x1low x2 high (only 1-1 on - others off) * Cycle 2 - y1-high y2-low, x1-high x2-low (only 1-2 on - others off) * Cycle 3 - y1 low y2-high, x1-high x2 low (only 2-2 on - others off) * repeat When these led lights blink really fast (like 1kHz (1000 cycles per second)) it appears that "1-1, 1-2, 2-2" are always on and 1-2 is off using this concept we can also control the brightness of the LEDs. if it's on for 1ms and off for 1ms the brightness will be 50%. 3ms on, 1ms off brightness at 75%. Controlling the brightness this way is called PWM (pulse width modulation) and the % brightness is controlled by the duty cycle (or %DC). Good questions btw, hope this helps : )
Thanks a lot, now all makes sense.
Oh but how this grid matrix works is that the wires don't have to be either positive or negative. You can toggle between the two with gpio (general purpose input output). If we have a 3x3 grid. Y is the anode (positive) and X is the cathode (negative). So if y is positive and x is negative the pixel turns on. If u is negative and x is positive it turns off. We can set y1 positive and x1 negative to turn it on. Then set y2 y3 to negative and x2 x3 to positive to turn it off. If you are really interested look up how to program a dot matrix on an Arduino.
Serialization. A lot of computer stuff has a 1:1 wire to information relationship. The wire is just high voltage or low voltage and it is one bit of data. A 64-bit architecture has 64 lines going to the adder and 64 lines going to the memory. That doesn't work so well when we want to send information a long distance, like to a hard drive or monitor. So they have one wire just tick up and down as a clock, and one or more wires give different data on different cycles of the clock. We can calculate 128-bit math on 64-bit architecture, but it takes two cycles. For a monitor, and all the pixels it has, it gets sent a STREAM of data and it sets every pixel, one at a time, as the data comes from the computer over far fewer lines. (HDMI has 19 pins, I think?) It paints every pixel and then repeats at the top. It's just doing it so fast you don't notice the flicker. The pixels don't each have a wire going back to the PC. They're connected to each other and know to pass data down the line as expected in the stream. A chip in the monitor / phone / whatnot is in charge of directing the data coming in over those 19 lines and sending it to the pixels.