Author Topic: Is there a standard seven segment mechanical dimension drawing?  (Read 2431 times)

0 Members and 1 Guest are viewing this topic.

Offline rcbuckTopic starter

  • Frequent Contributor
  • **
  • Posts: 378
  • Country: us
Is there a standard seven segment mechanical dimension drawing?
« on: January 08, 2023, 02:23:45 am »
Are 7 segment digits standardized for angle and section lengths? I haven't been able to find a data sheet that gives all the dimensions. I did find the attached data sheet but it does not show the angles of the individual segment end points.

I have physically looked at several units of varying sizes that I have on hand. They all seem to be very similar in the angles where the segments meet each other. I have found that the slope of the digit appears to be either 5° or 10° from the vertical axis.
 

Offline floobydust

  • Super Contributor
  • ***
  • Posts: 9069
  • Country: ca
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #1 on: January 08, 2023, 04:52:51 am »
I would say "no". LED displays settled into standard heights and pinouts in the late 1970's. Everything from 0° to 15° tilt is out there.
The tilt (effect) also depends on the height and I fuzzily remember it's about human physiology whereas the brain's visual system has feature detectors (horizontal and vertical) and the tilt bypasses that. But it could be malarkey. Russian 7-seg displays are also quite different so it could be a font thing.
The segment thickness, tilt, interdigit spacing etc. I recall was only delved into in American military ergonomic standards (avionics) where fast readability and some uniformity is required.
Pre-LED era, RCA numitrons were offered with either 0° or 4° tilt. I'm not sure why.
 

Offline Terry Bites

  • Super Contributor
  • ***
  • Posts: 3172
  • Country: gb
  • Recovering Electrical Engineer
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #2 on: January 08, 2023, 03:47:05 pm »
 It very likely that there are EIA/ JDEC standards (pay per view of course).
Industry standard footprints let you second source your parts.
So you usually have to follow rules to compete in the same market.
Vendors want you to persuade you come over to their product line without forcing a redesign on you.

If you look at data sheets for similar sized displays you'll find that they often are identical in footprint and general dimensions.


 

Offline rcbuckTopic starter

  • Frequent Contributor
  • **
  • Posts: 378
  • Country: us
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #3 on: January 08, 2023, 04:47:08 pm »
Thanks for the replies. I suspected that there was no standard for digit mechanical details like there are for footprints. Even footprints sometimes vary according to manufacturer.

I was looking for a data sheet that gives the angles and spacing between segments. I am going to design and 3D print a 5 inch digit to use in a GPS clock I am building. I can buy one for less than I can build one. But that is no fun.

I will use a 2.3 inch digit I have here to take measurements and do the math to scale it to 5 inch size.
 


Offline intabits

  • Frequent Contributor
  • **
  • Posts: 345
  • Country: au
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #5 on: January 13, 2023, 10:39:11 pm »
A had a similar problem a couple of years ago, where I wanted a 7-segment display in a PC program.
I found a freeware component that did the job, but it was very crappy looking.
So I decide to write my own, but like you, could not find any mechanical/dimensional specifications for 7-segment displays.

To get the mechanical specs, I searched the web for the highest quality and resolution image of such a display that I could find, and wrote a program whereby I could "digitize" the coordinates of each corner of each segment by clicking the mouse over the hi-res image.

My final result was a very realistic simulation of a PDP11/34 console:-


which can be seen operating in this video:-



The definitions for the segments that I used in my code are:-
Code: [Select]
// Map of segment vertex coordinates
Const SampleSizeX=1714; SampleSizeY=2638;

      SampleSegVertices: Array[TSegmentID] Of Array[1..6] Of Array[1..2] Of Integer=(
        (( 311,  66),( 375,   1),(1577,   0),(1633,  63),(1376, 302),( 520, 301)),
        ((1650,  96),(1714, 160),(1593,1325),(1451,1321),(1312,1171),(1400, 324)),
        ((1442,1357),(1587,1364),(1474,2495),(1400,2557),(1193,2335),(1277,1504)),
        ((1379,2575),(1311,2638),( 140,2634),(  85,2574),( 329,2350),(1171,2351)),
        ((  64,2545),(   0,2484),( 110,1346),( 253,1353),( 391,1501),( 312,2328)),
        (( 250,1317),( 109,1309),( 215, 155),( 287,  94),( 499, 326),( 420,1162)),
        (( 277,1333),( 434,1188),(1282,1188),(1418,1335),(1258,1484),( 411,1480))
      );
Each row is for one segment, each of which has six corners at the points specified.
SampleSizeX/Y are the width and height of the whole digit.
From those numbers, I think it would be fairly easy to scale those coordinates to whatever size you want.
Hope that helps...
 
 

Offline jbeng

  • Regular Contributor
  • *
  • Posts: 53
  • Country: us
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #6 on: January 13, 2023, 11:47:25 pm »
1983 General Instruments Opto Data book shows the majority of 7-segment displays listed have a 10 degree slant to the right; a few show 8 degrees

1985 Hewlett Packcard Opto Designer Catalog shows the same, with bubble-style multidisplays at 5 degrees

1990 LED and LCD Products databook from "AND" shows the same.  Angles for the LCD products were not shown

1995-96 Quality Technologies Opto Product databook shows mostly the same, with some listed at 5 degrees

The various databooks show a range of segment sizes and shapes for the products that were manufactured at the time; I expect the same is true for currently manufactured displays
« Last Edit: January 13, 2023, 11:49:22 pm by jbeng »
"It's such a fine line between stupid and clever" - David St. Hubbins
 

Offline bidrohini

  • Regular Contributor
  • *
  • Posts: 201
  • Country: bd
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #7 on: January 16, 2023, 09:12:29 am »
Here is a dimension diagram of standard size 7 segment display. https://components101.com/displays/7-segment-display-pinout-working-datasheet
 

Offline Leeima

  • Contributor
  • Posts: 31
  • Country: gb
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #8 on: January 18, 2023, 06:54:23 pm »
To get the mechanical specs, I searched the web for the highest quality and resolution image of such a display that I could find, and wrote a program whereby I could "digitize" the coordinates of each corner of each segment by clicking the mouse over the hi-res image.

I would have just opened the image in MS Paint and looked at the cursor coordinates in the bottom left  :-DD
 
The following users thanked this post: intabits

Offline Nominal Animal

  • Super Contributor
  • ***
  • Posts: 8349
  • Country: fi
    • My home page and email address
Re: Is there a standard seven segment mechanical dimension drawing?
« Reply #9 on: January 18, 2023, 07:06:30 pm »
I'd just use Inkscape.  Examine the SVG <path d="path" .../> elements, and you have the 'pixel' coordinates of the shapes.  The d="path" specification is simple.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf

 

-->