Dot-matrix vs segment

[Lillegutt]

I have tried some searches in this forum and 'out there' without getting any straight answers.

Do you know the differences in timeline for when dot-matrix displays were used in different models, and when they started using 7-segment displays?


JHH

[retroleds]

Technically, both types are seven segements, but the segments are made up of a row of dots, versus a singular bar in each type.Specific timelines vary by manufacturer....Pulsar switched over in mid to late 1975.

[LEDluvr]

What about Hughes - when did they switch over from dot matrix to bar segment?

[azimuth_pl]

Hughes switched approx. mid-1975 as the BigBlock from 1974 has dot-matrix and some early 1975 Hughes also have dots.

[TheFordGuy]

Just how small are the dots? I'm trying to figure out if my Compu Chron is a dot or segment display. Under very close eyeballing, it appears as if each segment is made up of dots, but they're incredibly small. The Pulsar dot-matrix displays seem more obvious.

Under closer examination with a magnifying glass, it's still hard to tell...Each short "segment" appears to be made of at least 10 "dots", but they're not clearly defined as dots, but rather look like each segment is "serrated" like the side of a steak knife.

I'm really curious now. Would the segments be smoother looking if that's what it is, or is that how they look?

[retroleds]

Different modules have different dot sizes due to their construction.
Dot type have a strip of gold or copper alloy with 7-10 holes in it, making up each segment. Some have serrations along one side, some have cuts that go all the way across, some a row of dots down the center. It was a time of developement and everyone was trying new things. Pulsar was the first, and had the earliest and largest displays, hence the visible dots. Early N.S. have dots that are visible, then the next wave of them have dots that are barely perceptible, then they just let the entire segment strip be "light" - bar displays. Early Pulsar display segments are 30-40% longer than most later brands of dot segments, so their dots could be spaced farther apart. The technologies are very similar....mainly a interesting design artifact that allows us to say," that's an early one, that's a later one".

[LEDluvr]

Thanks for the history lesson guys!
Q:
I never really had an interest in collecting Texas Instrument's LEDs until recently. But now that I'm paying attention to them I don't think I've ever seen a TI with dot matrix. Do they exist?
Or did TI get into the LED watch market after the bar segment was the norm?

[azimuth_pl]

TI joined the gang as one of the last with their cheaper watches and the first plastic one for less than 20$ (the grey or black plastic ones sold at the movies in 1977 when Star Wars was launched). I think they produced some components for the market before introducing their own final product.

as for the dot-matrix, these should be visible with the naked eye.
if not, they are considered segment type.
below is the 1974 Hughes display from the Bigblock:

[retroleds]

...as for the dot-matrix, these should be visible with the naked eye.
if not, they are considered segment type.

Some of us old farts can't tell the difference without our reading glasses.

[TheFordGuy]

Mine must be a segment style then...The dots in that early Hughes module are distinctly visible, where mine just look like jagged edges along the segments.

[LEDluvr]

TI joined the gang as one of the last with their cheaper watches and the first plastic one for less than 20$ (the grey or black plastic ones sold at the movies in 1977 when Star Wars was launched).

Actually, the Star Wars TI was my first LED watch!
For some odd reason my dad didn't see the logic in buying a 10 yr. old boy a Pulsar LED.

Not that it stopped my from trying!