The Technology Vent and Rant Thread

[Renate]

Sorry, I was speaking of colored panel indicators.
I pick a nice yellow when I only need one color.

For white-ish things I really dislike all this super warm 2000k on displays.
I call that "red".

[Quoth]

I really hate the "fashion" in the last few years to have really bright "power indicators" and especially blue LEDs for things that don't need blue.

The amber, yellow and green are pleasant if not too bright. Red for fault and Green for OK is a bad combo for the most common colour "blindness". Unfortunate for Port and Starboard. Would yellow for OK and blue for fault be better?

Red was the first visible LED (late 1960s? though modern LEDs invented in 1962) and then there was green in the 1970s. Now there are many native colours without a phosphor.

[ratinox]

Originally Posted by Quoth

I really hate the "fashion" in the last few years to have really bright "power indicators" and especially blue LEDs for things that don't need blue.

I hate blue LEDs. They're a pox, a bane on the existence of tech outside of the data center racks where having a different color from the rest of der blinkenlichten is useful.

Fortunately, gaffer tape exists.

[jbjb]

Originally Posted by Quoth

Natively white LEDs don't exist.

They actually do exist, they're just not (yet) mainstream. Monolithic InGaN LEDs with multiple quantum wells can produce white light without the use of phosphors.

[j.p.s]

Do 4 lead, three die (R, G, B) LEDs count as white? They have been around for quite a while.

[jbjb]

Originally Posted by j.p.s

Do 4 lead, three die (R, G, B) LEDs count as white? They have been around for quite a while.

I'd say that counts as 3 LEDs packaged together, not a single LED. The multiple quantum well white LEDs on the other hand are genuinely monolithic - grown on a single substrate.

[Quoth]

Originally Posted by j.p.s

Do 4 lead, three die (R, G, B) LEDs count as white? They have been around for quite a while.

A regular "white" LED is blue or violet with one or more phosphors to give broad spectrum (colour rendition) so they can be used to illuminate.

An RGB LED only has narrow almost monochrome red, green and blue light. The relative red and blue adjusts the apparent colour temperature, but the colour rendition is absolutely terrible. Actually near monochrome yellow, orange, cyan, violets (rather than true magenta which is an illusion as it's a lack of green) etc will be the wrong colour or dark.

White light is obtained by using multiple semiconductors or a layer of light-emitting phosphor on the semiconductor device.

But the non-phosphor method is useless for room or street lights.
https://en.wikipedia.org/wiki/Light-...ode#White_LEDs

See Colour Rendition to understand why all viable commercial LED lights to replace incandescent or CFL etc uses phosphors.

Numerically, the highest possible CIE Ra value is 100 and would only be given to a source whose spectrum is identical to the spectrum of daylight, very close to that of a black body (incandescent lamps are effectively black bodies), dropping to negative values for some light sources. Low-pressure sodium lighting has a negative CRI; fluorescent lights range from about 50 for the basic types, up to about 98 for the best multi-phosphor type. Typical white-color LEDs have a CRI of 80 or more, while some

A tri-colour R G B LED with no phosphors would be near zero CRI
Note that higher CRI (80 to 95) have lower efficiency than low CRI of 50.
https://en.wikipedia.org/wiki/Color_rendering_index

So an R G B LED source can be used for LCD backlights, and projectors onf any kind as those are not room illumination, but playing back a signal created by filtering the image to match the average human eye response to three channels, either R G B or brightness and two chroma channels. As the filterin was done at the camera or scanner, the display can use narrow R G B at approximately the peaks.

Pure R G B sources are terrible for actual general lighting.

[Quoth]

Originally Posted by j.p.s

Do 4 lead, three die (R, G, B) LEDs count as white? They have been around for quite a while.

No they are not really white illumination. Just any colour of indicator, including the same illusion of white as any display screen.

Originally Posted by jbjb

I'd say that counts as 3 LEDs packaged together, not a single LED. The multiple quantum well white LEDs on the other hand are genuinely monolithic - grown on a single substrate.

There are no white LEDs. Just nearly monochrome with phosphors. Blue, Violet or UV.
The filament stick LED lamps have maybe 22 LEDs (minimum) in series on sapphire rod coated in mostly yellow phosphor. Shine UV or a bright blue LED in the dark on one that's off.

Some have better colour rendition by adding a second or third phosphor and even interspersing some other colours of LED. They are more efficient and longer life.
* Each stick might be about 55 V, so the power supply is more efficient than smaller number of chips in a spot lamp etc.
* The LED temperature is lower due to many more chips, so phosphor lasts better.
* The LED temperature is lower due to design and cooling gas fill.
* The light level per sq mm of phosphor is lower so phosphor lasts better.

They also give a more omnidirectional light.

[jbjb]

Originally Posted by Quoth

A tri-colour R G B LED with no phosphors would be near zero CRI
Note that higher CRI (80 to 95) have lower efficiency than low CRI of 50.
https://en.wikipedia.org/wiki/Color_rendering_index

So an R G B LED source can be used for LCD backlights, and projectors onf any kind as those are not room illumination, but playing back a signal created by filtering the image to match the average human eye response to three channels, either R G B or brightness and two chroma channels. As the filterin was done at the camera or scanner, the display can use narrow R G B at approximately the peaks.

Pure R G B sources are terrible for actual general lighting.

The multiple quantum well monolithic white LEDs can get a CRI into the high 80s, which is fine for lighting.

They're still (as far as I know) not ready for commercial use, but they do exist and I suspect it's only a matter of time.

[jbjb]

Originally Posted by Quoth

There are no white LEDs. Just nearly monochrome with phosphors. Blue, Violet or UV.

There *are* white LEDs, as I've explained above. Still experimental technology, but they exist in the lab and look promising for commercial development.

[Quoth]

Originally Posted by jbjb

There *are* white LEDs, as I've explained above. Still experimental technology, but they exist in the lab and look promising for commercial development.

You can't buy them, and they can't be decent colour rendition without a layer on top of the LED.

LEDs work by a band gap* which sets the narrow band colour. If such a lab device really gives broad spectrum light then it's not really an LED.

[* That is defined by the materials, though temperature and current do shift the narrow band emission]

So, no there are currently no actual LEDs that are natively white, and if what ever that is ever leaves the lab to production it will turn out to be not actually an LED.

OLED for example are not "real" LEDs. They are actually diode-like electroluminescent printed dots with phosphors to get the red, green and blue colours. There are some very expensive displays that use real LEDs. Nothing domestic. QLED panels are actually LCD panels with a blue LED backlight and "quantum" dots for the red and green parts of the LCD. These are more efficient than phosphors with also a faster response time. Phosphors are slow.

[JSWolf]

Originally Posted by Quoth

You can't buy them, and they can't be decent colour rendition without a layer on top of the LED.

LEDs work by a band gap* which sets the narrow band colour. If such a lab device really gives broad spectrum light then it's not really an LED.

[* That is defined by the materials, though temperature and current do shift the narrow band emission]

So, no there are currently no actual LEDs that are natively white, and if what ever that is ever leaves the lab to production it will turn out to be not actually an LED.

OLED for example are not "real" LEDs. They are actually diode-like electroluminescent printed dots with phosphors to get the red, green and blue colours. There are some very expensive displays that use real LEDs. Nothing domestic. QLED panels are actually LCD panels with a blue LED backlight and "quantum" dots for the red and green parts of the LCD. These are more efficient than phosphors with also a faster response time. Phosphors are slow.

The new Samsung 115" Micro-LED TV is about $30,000.

[Quoth]

Bubble memory looked promising 50 years ago and was briefly used.

Worm drives and Holgraphic storage looked promising 20 to 30 years ago. We are still waiting for it.

Magneto Optic storage did deliver, but eventually Flash and writeable DVD/BD replaced it.
Optane looked promising, but is gone.

In the 1950s Atomic power promised us almost free electricity. Then later Fusion power was only 10 or 20 years away, 50 years ago.

Things claimed in labs may or may not ever see the light of day.

Beam indexing CRT (no shadow mask or Trinitron grid) was promised for colour TV in 1951. In the late 1990s it was finally working, but never reached the market because colour LCD was dramatically improving.

Electronic TV was outlined in 1905, but it took till 1935 to solve the issues with the camera. The CRT already existed in 1905!

Transistor theory was known in the 1920s but it took till 1948 to demo it (material purity was the issue) and about 1950 for decent production. It 1954 for the first transistor radio and they weren't economic to replace valves till 1958.

Magnetic tape recording was demonstrated in the late 1890s and Fax in 1851. But it was Telefunken in the 1940s that first had viable tape recording.

The liquid hydrogen & oxygen engine for rockets to the moon was demoed in a lab in 1930s.

The first aircraft to take off, fly and land automatically was 1972. But that's not commonplace yet.

[Quoth]

Originally Posted by JSWolf

The new Samsung 115" Micro-LED TV is about $30,000.

Sony had a small $10,000 real LED TV / Video monitor for broadcasters some years ago. They called it Crystal LED because TV makers had already called LED backlit LCD TV, "LED TVs". But crystal might mean something different now. QLED is misleading.

It's HATEFUL the misleading adverts.

I wanted a BT mouse to save a USB port and visited town today. Loads of wireless mouse brands. However EVERY SINGLE ONE used a USB "dongle" and none used BT. So pointless.

Maybe I'll get a real BT mouse online.

Also I want an HDMI splitter. You know feed two screens at same settings from one source. But all the ones I was shown were bidirectional HDMI switches. Either switch between two sources to one screen, or select one source to EITHER screen (not both at the same time).

[Quoth]

Originally Posted by JSWolf

The new Samsung 115" Micro-LED TV is about $30,000.

That's interesting, but given the average "lounge" size and income here, plus likely €37K (Europe pricing and local VAT) it sounds more Corporate than domestic.

I suppose there is a USA domestic market for it if it's 4K. Dynamic range & response time should be good.