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LCD with large active area versus outer dimensions

Started by Klaus Kragelund August 23, 2012
Hi

We have been getting some information on a FSTN LCD display we need, rarthe=
r small, 20mm x 30mm. It is for an industrial product with 10years lifetime

The problem is when we specify a resolution of 64x64 pixels, the Y pixels a=
re access by the LCD controller by routing on either side of the display do=
ts (on the left and right side). But, this routing occupies space, so havin=
g a display of 20mm outer dimension (x) actually only have an active area (=
visible dots) of 12mm

So, I am trying to see if this is real or just from the manufactor we have =
contacted. Anyone have worked with LCD and specs that can verify this? (tha=
t the active area is reduced that much). We could reduce the number of y pi=
xels, that will cause less routing and larger active area, but then the dis=
play looks crude....

Also, maybe another alternative display?

Sofar we have gotten the feedback, that TFT is to expensive (and have probl=
ems of availability due to sourcing to the mobile industry), CSTN (Color ST=
N) is old tech and is obsolete shortly, OLED has very low lifetime (3 years=
).

Thanks

Klaus
On a sunny day (Thu, 23 Aug 2012 15:26:16 -0700 (PDT)) it happened Klaus
Kragelund <klauskvik@hotmail.com> wrote in
<b831d001-5fca-4f8b-8eab-4cebab174c5f@googlegroups.com>:

>Hi > >We have been getting some information on a FSTN LCD display we need, rarthe= >r small, 20mm x 30mm. It is for an industrial product with 10years lifetime > >The problem is when we specify a resolution of 64x64 pixels, the Y pixels a= >re access by the LCD controller by routing on either side of the display do= >ts (on the left and right side). But, this routing occupies space, so havin= >g a display of 20mm outer dimension (x) actually only have an active area (= >visible dots) of 12mm
It happens quite often, there is a large empty area before the pixels start in many (most?) LCDs.
>So, I am trying to see if this is real or just from the manufactor we have = >contacted. Anyone have worked with LCD and specs that can verify this? (tha= >t the active area is reduced that much). We could reduce the number of y pi= >xels, that will cause less routing and larger active area, but then the dis= >play looks crude.... > >Also, maybe another alternative display?
There usually is a lot of drive electronics, and the besel (edge) too, so you will have to hide that too. Then why not use a bigger display and hode the part that has no data?
>Sofar we have gotten the feedback, that TFT is to expensive (and have probl= >ems of availability due to sourcing to the mobile industry), CSTN (Color ST= >N) is old tech and is obsolete shortly, OLED has very low lifetime (3 years= >). > >Thanks > >Klaus >
CTRTs last a very long time, old ones had phosphor all the way to the edge :-)
Jan Panteltje wrote:
> > CTRTs last a very long time, old ones had phosphor all the way to the edge :-)
Some CRTs had it wrap around the edges for an inch or more, which was interesting on overscanned applications. ;-)
It seems that this thread is living in 1980s technology.

LCD panels with a large metal holder has a zebra strip connection for 
the glass to the pcb. That strip need to be compressed to get a connection.

Look at COG displays and you will find a larger active area.

hamilton
On a sunny day (Fri, 24 Aug 2012 09:34:44 -0400) it happened "Michael A.
Terrell" <mike.terrell@earthlink.net> wrote in
<UpmdnZUZKrBgH6rNnZ2dnUVZ_g-dnZ2d@earthlink.com>:

> >Jan Panteltje wrote: >> >> CTRTs last a very long time, old ones had phosphor all the way to the edge :-) > > > Some CRTs had it wrap around the edges for an inch or more, which was >interesting on overscanned applications. ;-)
Used this in an a homebuild scope long time ago, DG7-32: http://www.r-type.org/exhib/aar0022.htm
Den fredag den 24. august 2012 15.57.12 UTC+2 skrev Jan Panteltje:
> On a sunny day (Fri, 24 Aug 2012 09:34:44 -0400) it happened "Michael A. > > Terrell" <mike.terrell@earthlink.net> wrote in > > <UpmdnZUZKrBgH6rNnZ2dnUVZ_g-dnZ2d@earthlink.com>: > > > > > > > >Jan Panteltje wrote: > > >> > > >> CTRTs last a very long time, old ones had phosphor all the way to the edge :-) > > > > > > > > > Some CRTs had it wrap around the edges for an inch or more, which was > > >interesting on overscanned applications. ;-) > > > > Used this in an a homebuild scope long time ago, DG7-32: > > http://www.r-type.org/exhib/aar0022.htm
Looks nice, but it has to fit in a 20mm times 30mm box. Don't think CRTs come that small and with only 3V supply :-)
On a sunny day (Mon, 27 Aug 2012 01:14:01 -0700 (PDT)) it happened Klaus
Kragelund <klauskvik@hotmail.com> wrote in
<fb3ce417-5720-45d7-b6e0-83040a534876@googlegroups.com>:

>Den fredag den 24. august 2012 15.57.12 UTC+2 skrev Jan Panteltje: >> On a sunny day (Fri, 24 Aug 2012 09:34:44 -0400) it happened "Michael A. >> >> Terrell" <mike.terrell@earthlink.net> wrote in >> >> <UpmdnZUZKrBgH6rNnZ2dnUVZ_g-dnZ2d@earthlink.com>: >> >> >> >> > >> >> >Jan Panteltje wrote: >> >> >> >> >> >> CTRTs last a very long time, old ones had phosphor all the way to the edge :-) >> >> > >> >> > >> >> > Some CRTs had it wrap around the edges for an inch or more, which was >> >> >interesting on overscanned applications. ;-) >> >> >> >> Used this in an a homebuild scope long time ago, DG7-32: >> >> http://www.r-type.org/exhib/aar0022.htm > >Looks nice, but it has to fit in a 20mm times 30mm box. Don't think CRTs come that small and with only 3V supply :-)
The supply voltage can be fixed wit ha converter :-) How about one of those cellphone displays, ebay has them I have seen them.
On Mon, 27 Aug 2012 09:33:14 GMT, Jan Panteltje
<pNaonStpealmtje@yahoo.com> wrote:

>On a sunny day (Mon, 27 Aug 2012 01:14:01 -0700 (PDT)) it happened Klaus >Kragelund <klauskvik@hotmail.com> wrote in ><fb3ce417-5720-45d7-b6e0-83040a534876@googlegroups.com>: > >>Den fredag den 24. august 2012 15.57.12 UTC+2 skrev Jan Panteltje: >>> On a sunny day (Fri, 24 Aug 2012 09:34:44 -0400) it happened "Michael A. >>> >>> Terrell" <mike.terrell@earthlink.net> wrote in >>> >>> <UpmdnZUZKrBgH6rNnZ2dnUVZ_g-dnZ2d@earthlink.com>: >>> >>> >>> >>> > >>> >>> >Jan Panteltje wrote: >>> >>> >> >>> >>> >> CTRTs last a very long time, old ones had phosphor all the way to the edge :-) >>> >>> > >>> >>> > >>> >>> > Some CRTs had it wrap around the edges for an inch or more, which was >>> >>> >interesting on overscanned applications. ;-) >>> >>> >>> >>> Used this in an a homebuild scope long time ago, DG7-32: >>> >>> http://www.r-type.org/exhib/aar0022.htm >> >>Looks nice, but it has to fit in a 20mm times 30mm box. Don't think CRTs come that small and with only 3V supply :-) > >The supply voltage can be fixed wit ha converter :-) > >How about one of those cellphone displays, ebay has them I have seen them.
There are also some small OLED displays- TI (nee Luminary) uses them on some of their dev boards. SPI interface, so not many wires.