How Do Touch Screens...Touch?
Summary
TLDRThe video explains how touchscreens work, contrasting the technology used in phones versus kiosks. It breaks down the layers of a phone's touchscreen - strong Gorilla glass on top, then a grid that stores electric charge, detecting disruption when touched. It notes how gloves and wet fingers interfere with this system. Finally, it explains how screens display color via pixels containing red, green and blue light emitters, which combine to form millions of colors across the high resolution display.
Takeaways
- ๐ฒ Touch screens work by detecting changes in electric charge distribution caused by touch
- ๐จโ๐ฌ Gorilla glass makes touch screens durable
- ๐ McDonald's kiosks use pressure-sensitive touch screens with less precision
- ๐ฑ Smartphones use capacitive touch screens that detect finer changes
- ๐ The capacitive grid holds electric charge like a capacitor
- ๐ง The processor detects changes in charge distribution when touched
- ๐ก Fingers conduct electricity to alter charge while gloves insulate
- ๐ Wet fingers confuse the screen by activating multiple points
- ๐จ Pixels use RGB colors to create images on the display
- ๐ฐ It costs one subscribe for this smartphone lesson!
Q & A
What are the two main types of touch screens explained in the video?
-The two main types are resistive touch screens, like those used in McDonald's kiosks, and capacitive touch screens, which are used in most personal devices like phones and laptops.
What is gorilla glass and why is it important for touch screens?
-Gorilla glass is a type of very strong, durable glass that is used for the top layer of capacitive touch screens. It provides protection for the sensitive layers below.
How does a resistive touch screen work?
-A resistive touch screen has two plastic layers coated in a conductive material. When pressed, the layers connect to detect the touch. However, it requires more pressure than a capacitive screen.
What are the main layers in a capacitive touch screen?
-The main layers are 1) the top gorilla glass layer, 2) a grid that holds a negative charge, 3) a grid that stores a positive charge when the first grid is near, and 4) a processor that detects changes in charge.
How does a capacitive touch screen detect touch location?
-The positively charged grid has a precise diamond pattern. When a finger touches the screen, it changes the charge at specific diamonds. The processor matches these locations to the display.
Why don't gloves work on capacitive screens?
-Gloves act as an insulator that blocks the electrical interaction between the screen and your finger needed for capacitive sensing.
Why do water drops sometimes cause issues with capacitive screens?
-Water is conductive so it can activate multiple points on the grid at the same time, confusing the processor.
How does a screen display color?
-Each pixel contains red, green and blue subpixels. By controlling the brightness of each one, any color can be produced.
Where does the glass for touch screens come from?
-It starts as high purity silica sand which is melted and molded into glass sheets.
What enables touch sensing in a resistive screen?
-The two plastic layers are coated in a conductive material that allows electricity to pass between them when pressed.
Outlines
๐ฒ How Touchscreens Work
Explains the components and functionality of a touchscreen. A touchscreen is made of strong gorilla glass with a grid of conductive material that creates an electric field. When you touch the screen, it detects the change in charge in that grid section and interprets your touch. There are two main types - less sensitive but more durable plastic/glass screens used in kiosks, and highly sensitive capacitor-based screens used in phones and laptops.
Mindmap
Keywords
๐กGorilla Glass
๐กConductive Material
๐กGrid Pattern
๐กCapacitor
๐กProcessor
๐กPixel
๐กDimmer
๐กInsulator
๐กElectric Field
๐กSubscribe
Highlights
Glass is made by melting high purity silica sand and pouring it into a mold.
Glass is given a chemical treatment to make it very strong, called gorilla glass.
Touch screens have a conductive material in a grid pattern to detect touches.
The grid allows the processor to match touches to what's on the screen.
Some touch screens use pressure while phones use capacitance.
Phone touch screens have 4 layers - glass, 2 grids to hold charge, and an insulator.
The grids act as a capacitor to store charge and detect changes from touches.
Touches change the charge in the grids, detected by the processor.
Bare fingers work by conducting electricity to change the charge.
Gloves don't work because they are insulators that block electricity.
Wet hands confuse the screen by activating multiple points.
Pixels have red, green and blue subpixels to create any color.
Varying the dimming of the subpixels generates different colors.
Millions of pixels together can make any image on the screen.
The touch screen layers and pixels make the displays functional.
Transcripts
how can a piece of glass know you're
touching it what kind of black magic is
this like at one point your phone screen
was literally just sand and using
science and technology that sand became
this Yes actually let me show you how
step one get some glass first melt some
high Purity silica sand and pour it into
a mold sort of thing boom glass but that
glass breaks really easy not good so we
give that glass a chemical manicure and
make it very strong we call this gorilla
glass step two the touch there are two
kinds of touch screens the one your
phone uses and the Annoying kiosk at
McDonald's first let's talk about the
McDonald's kiosk this one has two layers
usually being plastic on top and glass
behind it both pieces are slathered in a
conductive material that means when they
touch it makes electricity so if you put
one just a little bit in front of the
other and attach them to something you
get a touchcreen but wait it knows it's
being touched but how does it know where
it's being touched well you remember
that slathering from earlier it's
actually a very precise slathering where
we slather in a grid pattern so if you
touch right here it will send
electricity to the processor like this
and the processor can match up with
what's on the screen and register if it
does anything pretty cool except it
sucks and you have to put an annoying an
an annoying and you have to put an
annoying amount of pressure for it to
work and it's not reliable but it's more
durable and lasts longer which is why
big companies like McDonald's use it so
they don't have to maintain it as much
the other kind is what your phone laptop
and pretty much any personal device
almost always use es this one has four
layers the top layer is the tough glass
we talked about in step one which
besides being kind of strong there's
really nothing special about this glass
it's just glass but below that glass we
have two clear diamond shaped grids with
a clear insulator in between them but
I'm going to make them colored cuz it's
easier to explain the grids are made
with a material called I which holds
electricity really well and it's
actually the same stuff we slathered on
the McDonald's kiosk but this time it's
just on its own under some glass if we
zoom in on the bottom grid we'll see a
ton of little electrons just chilling
they do this because there's an
insulator in between the two grids so
the electrons are kind of stuck they
really have no choice but to chill and
because these electrons aren't moving
they generate a negative electric field
which causes the top layer to store a
ton of positive charges this my young
Padawan Learners is what we call a
capacitor it build an electric field and
it's used in a ton of stuff so if you
were to put something that inducts
electricity close to this capacitor like
a hot dog it messes up the electric
field this changes the amount of
positive charge on that top layer now
keep in mind your phone knows exactly
how much charge is supposed to be on
each top Diamond so the processor in
your phone does the math and says yo
there's a change in charge on diamond
x50 y 173 then the chip in your phone
will look at what's displayed on x50 y
173 and if clicking there is supposed to
do something meaning if you tap right
here nothing happens but if you tap
right here your phone matches it up with
what's on the screen and subscribes to
this okay but why do touch screens work
with fingers and hot dogs but not gloves
also why does your touchcreen act all
weird when your hands are wet it's
because like I said before your finger
and a hot dog conduct electricity that
means when you put your finger near your
phone screen the electricity from the
capacitor literally runs through your
finger and that's what makes the change
in charge a glove however is an
insulator meaning electricity ignores it
so there's no change in charge then you
might say but what about water water
conducts electricity and that's true the
problem is when your hands are wet the
water activates at multiple points at
the same time and your phone just kind
of gets confused all right so we have
some glass the clear magic electricity
stuff but what about the screen itself
the colors how does that work step three
display everyone thinks they know how
pixels work and they probably do
basically if you zoom in on your screen
really really really really close you'll
see something called a pixel each pixel
is made of of three baby pixels that are
either red green or blue on top of each
baby pixel is a dimmer so if you want
this pixel to be the color red you'd
completely dim green and blue if you
want the color purple you'd dim green
completely and do 50% red 50% blue if
you want white you do them all at 100%
basically these three colors can make
any color and because you have millions
of pixels you can make any image jit
crazy after all eh anyway that's going
to cost you one subscribe and the
McDonald's kiosk is going to ask you a
few questions
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