Design of custom LCD glass

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Hi!

I want to design my own LCD glass. That is I want to make a drawing with physical dimensions and all the numeric characters and icons (annunciators) on the LCD.

From the STK502 User Guide there is a schematic of the LCD. I want to make a similiar approach.

In what software do LCD makers design their LCD glasses?

Do you think it's possible to get the actual digital CAD drawing from atmel/Hitech Displays/Acte?

I have mailed them.

Do you know where to get digital cad drawings of other LCD designs?

Kind regards

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You could give these folks a try. You really want the folks that are fabricating the display for you do handle the design of the glass itself. Talk to them about drawing formats they accept. They'll work with you on the design details.

http://www.densitron.com/display...

I googled custom lcd glass design. Here are the results.
http://www.google.com/search?hl=...

Tom

Last Edited: Mon. Jul 17, 2006 - 08:39 AM
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When we've had LCDs or VFDs made for us in the past we've just sent them a black and white image from Corel and the manufacturer has then been able to convert this into their own format. The LCDs were probably made by Seiko-Epson and the VFDs by Futaba I seem to remember.

Cliff

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Ah Densitron - I'd forgotten about them, they made the LCD panel+touch screen that we used in a PDA back in the mid 90's

@OP: I can't help thinking though that unless the volume is huge the amortisation of the NRE for having an LCD panel made will make the per unit cost very high and you may be better off just using a graphic panel in a standard pixel dimension used in some other high volume application (e.g. mobile phones) where the per unit cost has been driven very low.

Cliff

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zoomcityzoom wrote:
You could give these folks a try. You really want the folks that are fabricating the display for you do handle the design of the glass itself. Talk to them about drawing formats they accept. They'll work with you on the design details.

http://www.densitron.com/display...

I googled custom lcd glass design. Here are the results.
http://www.google.com/search?hl=...

Tom

But I want to design it myself with physical dimensions and such. And I tried googling but didnt find much that had to do with the software used.

Well the actual electrical drawings and such things "inside" the LCD the LCD manufacturer have to make. But I want to do the physical dimensions of the LCD digits, icons and the LCD glass like in the drawing in the STK502 User Guide.

That would feel better for me to do the design myself.

Thanks

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i guess that you'll gonna have to consult directly with them and ask what kind of data they want.

There are pointy haired bald people.
Time flies when you have a bad prescaler selected.

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Like Cliff said, I would use Corel Draw or some other drawing program that was compatible with the folks who are making the glass for you. Pick a few vendors/manufacturers from the Google search and find out what format they will accept your drawings in. Talk to their sales reps/engineers and ask questions about the process. Discuss NRE, pricing, lead times, and your your volume requirements. They'll be happy to explain the entire process. If they aren't, pick another manufacturer.

Tom

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At the end of the day you can fax them a hand drawn drawing. They will take it and produce what is called a counter drawing. This is fully dimensioned and shows the plane connections. But beware you will proberbly be charged (they will not tell you this, untill you put the order in) for each iteration. So get it right first time.

You will find it difficult getting any sense unless to get past the suits and talk the the factory. Not that the suits will admit they are a problem rather than a solution

Keep it simple it will not bite as hard

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Believe me, when it comes to getting custom LCDs or VFDs made the last thing that'll be of worry to you is how to get the segment images to the manufacturer. It's all the negotiation over tooling, unit cost and QC acceptance specifications that will be keeping you busy - the actual design is almost incidental!

Cliff

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Quote:
the actual design is almost incidental!

That explains why all custom VFD's in car radios and the such look so apocalyptically awful :D

The Dark Boxes are coming.

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I've used AZ Displays for a few designs.

http://www.azdisplays.com

I send them PDF files containing the critical glass dimensions and segment artwork and they return a counter drawing to match it, usually within a week or two. Things go batter if you let them pick the segment wiring and pin placement. The NRE for a small display (a few square inches and 100 segments) is $1000, which includes 5 samples of the display. Your samples arrive in 4-8 weeks.

Minimum order quantity is usually 500 to 1000 units and pricing depends on glass size and liquid (STN or FSTN). A very small display might cost $1. Under 10 square inches might be $5. Leadtime for production is 6-8 weeks.

If your design doesn't push the technology's limits, the process goes smoothly.

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ScottKroeger wrote:
I've used AZ Displays for a few designs.

http://www.azdisplays.com

I send them PDF files containing the critical glass dimensions and segment artwork and they return a counter drawing to match it, usually within a week or two. Things go batter if you let them pick the segment wiring and pin placement. The NRE for a small display (a few square inches and 100 segments) is $1000, which includes 5 samples of the display. Your samples arrive in 4-8 weeks.

In what software do you draw the segment work? In what format is the counter drawing they make from that? Or is it just a picture, not the actual digital cad drawing.

And when you paint it, do you use actual dimensions and grids so it looks almost perfect? (Ie exact height of icons and numeric characters)

I don't care about the segment wiring really, that can be fixed on the PCB. On the other hand, what do you mean with pin placement? If I want to use elastomeric connecters they must alight the pins correct.

Quote:
Minimum order quantity is usually 500 to 1000 units and pricing depends on glass size and liquid (STN or FSTN). A very small display might cost $1. Under 10 square inches might be $5. Leadtime for production is 6-8 weeks.

If your design doesn't push the technology's limits, the process goes smoothly.

I only need a duty 1/4 max so TN liquid will do. I'm looking into a LCD like in the STK502/Avr Butterfly but:

1. Bigger (about 5 square inches)

2. Different layout and icons

3. Different pin arrangement to make it connect with elastomeric connectors (zebra connectors or similiar).

Thanks

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clawson wrote:
Believe me, when it comes to getting custom LCDs or VFDs made the last thing that'll be of worry to you is how to get the segment images to the manufacturer. It's all the negotiation over tooling, unit cost and QC acceptance specifications that will be keeping you busy - the actual design is almost incidental!

Cliff

Yeah but I thought that would make it a bit cheaper. :idea:

But I guess it's more important to look at the NRE, unit cost and minimum unit order.

Once I'm done with an order, do I get the actual data they produced and charged me for so I could use this drawing at any manufacturer. Or do I need to go through all the design line again.

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I use Adobe Illustrator to draw my designs, but you can use anything that produces a PDF that looks good to you. I use Illustrator because it's a vector drawing program and produces vector PDFs. You could use Corel or AutoCAD too. My designs have had some bitmap content, rendered at 2400DPI. AZ returns the counter drawings in AutoCAD .DWG format.

By pin placement, I mean where the pins (or elastomeric contact pads) go, and how many you have. On large or crowded displays, you may need multiple common pins to ease routing and reduce common drive resistance. The manufacturer will figure this out during design. The mapping of common to segment and the placement and ordering of pins is best left to them. You can specify a pin pitch and a region in which you want pins placed, but beyond that any additional restrictions you put on placement just make life harder for the manufacturer, and the display more expensive for you.

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dynasty_ wrote:
Once I'm done with an order, do I get the actual data they produced and charged me for so I could use this drawing at any manufacturer. Or do I need to go through all the design line again.

But if you go to a second manufacturer they'll also impose an NRE tooling charge and will also have their own minimum order quantity too - so you want to be pretty sure you pick the right one in the first place.

Unless, of course, the second manufacturer is so eager to under-cut their competitor that they will waive any NRE charges - this has been known to happen ;)

Cliff

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Quote:

I can't help thinking though that unless the volume is huge the amortisation of the NRE for having an LCD panel made will make the per unit cost very high ...

Well, I don't know if I totally agree with "huge" and "very high". Especially if a "semi-custom" offshoot of a more-or-less stock design -- adding custom units symbols to a 4-digit, for example -- the NRE isn't too high and the cost/unit isn't bad since you are cutting out the middleman. If the customization is important to the app, a few hundred may be the break-even. Surprisingly, it doesn't need to be many thousands before it makes sense.

Now maybe a "full custom" with weired form factors and pinouts might be different.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Yup, "many thousands" -

Experience seems to show that the majority (though granted, not all) of the posts here tend to be about small projects between 1 (quite a lot of those!) and 1,000 units. Custom LCDs only really start to make sense once you are into higher volumes than this.

Maybe dynasty_ can give an idea of how many units we're talking about here?

Cliff

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I used to make LCD displays many years ago ( early '82 )

used to get in tin oxide glass cut to size, photo tool a film as per PCB industry, shipley chemical liquid photo resist ( positive) vials of liquid crystals, glass fret and araldyte epoxy adhesive.

coat glass with photo resist and make sure coating is uniform.

bake as per chemical suppliers instructions

expose and develop photo resist.

etch glass in mild HCl

strip residual photo resist.

used cling wrap to make a spacer gasket ( about 2 mm wide around periphery of glass) to minimise leakage of fluid during assembly proces.

used glass fret as a plate separator material on large glass plates ( plates for petrol bowsers )

load a plate with liquid crystal

place the other plate on top carefuly

soak up any excess fluid and seal edge of assembly with epoxy

and voila.. large custom display...

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I've done "weird" designs, and ones that were virtually identical to existing units. The NRE was the same for both and the unit price was more or less proportional to glass area. There is NO BENEFIT to making small modifications to an existing design. It's all just artwork, just as with a PCB. You don't get a discount from Olimex because your next board is 99.9% the same as your last one. You send new Gerber files and you pay the full NRE.

If you switch vendors you start over. They all have different front end capture processes, different manufacturing flows and different QC methods. Although they give you the .DWG file for your design, that's only a fraction of what they've done internally to make your display. They've also worked out ITO thickness and dielectric routing, liquid thickness, polarizer direction, panelization, adhesive masking, etc. You won't get that information from them and even if you did, the next manufacturer wouldn't take it from you, as it won't map onto their processes.

If you need only five units of a small, simple display, you can get that for $1000 from AZ, as they generally include 5 samples in the NRE. That's $200/display, but for a commercial project proof-of-concept that's reasonable. They'll make a few more in the prototype run if you pay them. I have done runs of only 25 units this way, at a cost of about $50 display and the economics were acceptable. Of course it is reasonable for them to expect you to do larger quantities for production, so don't ask them to routinely take orders for 10 units. They subsidize the NRE with your eventual production order.

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Ignoramus, If you could make a pseudo tutorial (with pictures!) on how to do this, I'm sure a lot of folks would love you to death. :)

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Quote:
Ignoramus, If you could make a pseudo tutorial (with pictures!) on how to do this, I'm sure a lot of folks would love you to death.

I second that fully, I'm starting with "to death" part right at the moment. I guess pictures may not have survived, but at least a more detailed explanation of the process would be priceless. Not that I'm going to make a custom LCD, these days I would rather try to find out about DIY OLED's (or DIY Nixie tubes) :) But still, I've never thought this is something that can be done at home and I'm very curious.

The Dark Boxes are coming.

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clawson wrote:
Yup, "many thousands" -

Experience seems to show that the majority (though granted, not all) of the posts here tend to be about small projects between 1 (quite a lot of those!) and 1,000 units. Custom LCDs only really start to make sense once you are into higher volumes than this.

Maybe dynasty_ can give an idea of how many units we're talking about here?

Cliff

I'm only need abot 50 units/year at this point, 1000 units is way too much.

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ScottKroeger wrote:
I use Adobe Illustrator to draw my designs, but you can use anything that produces a PDF that looks good to you. I use Illustrator because it's a vector drawing program and produces vector PDFs. You could use Corel or AutoCAD too. My designs have had some bitmap content, rendered at 2400DPI. AZ returns the counter drawings in AutoCAD .DWG format.

Okay, are the drawings at correct size and everything (height of icons and numerics)?

Quote:
By pin placement, I mean where the pins (or elastomeric contact pads) go, and how many you have. On large or crowded displays, you may need multiple common pins to ease routing and reduce common drive resistance.

Well I'm gonna use maximum of four (4) backplanes, the pins comming out of top and bottom of display (Dual inline).

Quote:
The manufacturer will figure this out during design. The mapping of common to segment and the placement and ordering of pins is best left to them. You can specify a pin pitch and a region in which you want pins placed, but beyond that any additional restrictions you put on placement just make life harder for the manufacturer, and the display more expensive for you.

Yes the ordering of the pins they can do, but I want of course choose to have the pins on the top and bottom. That should not be a problem as that is pretty standard (LCD in butterfly).

I guess it's better to design the elastomeric connector after I have the LCD.

Thanks

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ScottKroeger wrote:

If you need only five units of a small, simple display, you can get that for $1000 from AZ, as they generally include 5 samples in the NRE. That's $200/display, but for a commercial project proof-of-concept that's reasonable. They'll make a few more in the prototype run if you pay them. I have done runs of only 25 units this way, at a cost of about $50 display and the economics were acceptable. Of course it is reasonable for them to expect you to do larger quantities for production, so don't ask them to routinely take orders for 10 units. They subsidize the NRE with your eventual production order.

Yes I'm willing to pay more for fewer LCDs as $50/unit so acceptable.
I need to search and quote them all.

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ignoramus wrote:
I used to make LCD displays many years ago ( early '82 )

used to get in tin oxide glass cut to size, photo tool a film as per PCB industry, shipley chemical liquid photo resist ( positive) vials of liquid crystals, glass fret and araldyte epoxy adhesive....

Really, do you have any guide for that? (or any link)

Or could you make one ? Preferrebly with pictures. I have never heard of anyone doing a custom LCD glass theirself!

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Hi,

I worked with RCLDisplay in Hongkong. Everything was fine. --> www.rcldisplay.com
I made my drafts with EAGLE. I think they did their drwings with their own software.

Klaus
********************************
Look at: www.megausb.de (German)
********************************

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svofski wrote:
Quote:
these days I would rather try to find out about DIY OLED's (or DIY Nixie tubes) :) But still, I've never thought this is something that can be done at home and I'm very curious.

How's your Polish, Svofksi? Keep scrolling down here: http://www.fonar.com.pl/audio/inne/pwl/pwl.htm

Neil :shock:

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"Okay, are the drawings at correct size and everything (height of icons and numerics)? "

Yes, do the artwork 1:1, at sufficient resolution to produce the quality you want (if the artwork is vector, the manufacturer will handle resolution, otherwise I recommend 2400dpi for raster artwork). Most LCD manufacturers will take PDF, DXF/DWG. Some will take TIFF or other bitmap formats.

Make sure you include some reference lines and dimensions in your artwork so they've got something to use as a final check.

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@Neil: O.M.G. That's the real thing!

The Dark Boxes are coming.

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Yup. It can only count to three, though (0,1,2) :D

Neil

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MegaUSBFreak wrote:
Hi,

I worked with RCLDisplay in Hongkong. Everything was fine. --> www.rcldisplay.com
I made my drafts with EAGLE. I think they did their drwings with their own software.

was wondering if everyone who gets custom LCD displays, do you always use the LCD AVR's? or the non-LCD AVR's and direct drive the LCD with I/O pins?

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Direct drive displays eat pins fast. A typical 3-1/2 digit multimeter display with decimal points and a few icons would eat 25 -30 pins. Even the 100 segment limit of the 169 seems restrictive, and I've got a design using all 160 segments on a 3290. It seems you never have enough.

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ScottKroeger wrote:
Direct drive displays eat pins fast. A typical 3-1/2 digit multimeter display with decimal points and a few icons would eat 25 -30 pins. Even the 100 segment limit of the 169 seems restrictive, and I've got a design using all 160 segments on a 3290. It seems you never have enough.

sorry, when I was referring to direct drive, I didn't mean static LCD's, I mean creating the mux waveforms via software and the voltages via external resistors and spare I/O pins, see

http://www.zilog.com/docs/z8/app...

You use exactly the same amout of pins as the LCD AVR, it just allows you to use a cheaper and smaller AVR (not a bad thing!) at the cost of some waveform generation software and external resistors

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Quote:

You use exactly the same amout of pins as the LCD AVR, it just allows you to use a cheaper and smaller AVR (not a bad thing!) at the cost of some waveform generation software and external resistors

Huh? If I use exactly the same amount of pins, how does a "smaller" AVR do the job? And why would this "smaller" AVR necessarily be "cheaper"? And would the home-built LCD driving circuit have the sophistication and options and flexibility of the Mega169-family LCD subsystem?

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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Follow-up on "cheaper" AVR:

[price estimates in US$ using DigiKey qty. 100 prices]

While a Mega169 is certainly not in the same "value price" category as a Mega8 or Mega88, it is interesting to note the AVR pricing structure as the new generation of AVRs is being rolled out. The Mega169 is a virtual venerable old-timer, and has pretty much maintained pricing over the past few years.

Mega169 $5.00
Mega329 $4.43
Mega325 $4.00
Mega32 $4.75

and the centipede

Mega3290 $5.03

So, we have an anomaly in the pricing structure with a Mega169. The newer '329 gives twice as much flash (and SRAM and EEPROM) for a much lower price. Or say that the LCD driving system costs $0.43 ('325 vs. '329). Or say that a '3290 gives you 60% more segments than a '169, more I/O, more SRAM & flash & EEPROM, but costs the same as a '169. Or say that a '329 costs less than a Mega32 so Atmel is >>paying you<< to use the built-in LCD subsystem--it is cheaper to use the '329.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
Quote:

Huh? If I use exactly the same amount of pins, how does a "smaller" AVR do the job?

Because AVR's with the LCD driving circuits are not available on smaller cheaper AVR chips (Mega88, for example), so I am forced to buy a bigger AVR to begin with, whether I need the extra functionality or not.

Quote:

And why would this "smaller" AVR necessarily be "cheaper"?

Because, generally speaking, chip cost is proportional to die size and package size, the LCD driver takes up die space, Atmel charges you for that.

Quote:

And would the home-built LCD driving circuit have the sophistication and options and flexibility of the Mega169-family LCD subsystem?

Lee

The homebuilt would be less sophisticated, but flexibility, well you could use any I/O pins you needed, not just the ones assigned in the Mega169 family, and you could assign any pin on any side of the chip as either the COM or SEG, so routing could be easier, so the homebuilt has greater flexibility in some respects.

It all comes down to cost, I need the resources of a Mega88 with an LCD driver, the Mega88 is less then 1/2 price and 1/3 the size of the cheapest/smallest LCD AVR.

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Quote:

Quote:

Huh? If I use exactly the same amount of pins, how does a "smaller" AVR do the job?

Because AVR's with the LCD driving circuits are not available on smaller cheaper AVR chips (Mega88, for example), so I am forced to buy a bigger AVR to begin with, whether I need the extra functionality or not.

Thus the fallacy in your post--if you do your roll-your-own LCD control, how many segments could you control with a Mega88? Not enough to be useful.

So, give me an example of what type of LCD you are referring to, how many segments, how many commons, and how it can be done with a few-legger. Your original claim said the same number of pins.

Lee

You can put lipstick on a pig, but it is still a pig.

I've never met a pig I didn't like, as long as you have some salt and pepper.

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theusch wrote:
Quote:

Quote:

Huh? If I use exactly the same amount of pins, how does a "smaller" AVR do the job?

Because AVR's with the LCD driving circuits are not available on smaller cheaper AVR chips (Mega88, for example), so I am forced to buy a bigger AVR to begin with, whether I need the extra functionality or not.

Thus the fallacy in your post--if you do your roll-your-own LCD control, how many segments could you control with a Mega88? Not enough to be useful.

mega88 has 23 i/o pins, if you used them all at 1/2 bias 1/4 duty, thats 76 segments, but of course you be out of I/O pins, not very useful example unless you building a digial clock

Quote:
So, give me an example of what type of LCD you are referring to, how many segments, how many commons, and how it can be done with a few-legger. Your original claim said the same number of pins.

Lee

Ok, a more reasonable example, the LCD I am using is similar to the type in digital volt meters, 3.5 digits plus 10 or so Icons to indicated various status, is that useful to you? Maybe not, but It is to me.

So 3.5 digits is 22 segments, + 10 icons = 32 total segment total

using 1/2 bias, 1/4 duty, 4 common pins, 8 segment pins( controls 32 total segments by muxing) that uses 12 pins (same as the LCD AVR's), leaving 11 free pins , I use 3 for A/D inputs, a few switches monitors, etc.

perfectly reasonable application, in my opinion, no fallacy

Last Edited: Thu. Jul 20, 2006 - 03:36 AM
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If you really don't need to drive 100-160 segments, then a non LCD-AVR might make sense. A mega168 ($2.33@100) driving a 40 segment display is certainly more cost effective than a 169/329 if the few leftover pins are enough for you.

You won't get the lowest power consumption or adjustable contrast, but those aren't always needed.

And be careful about the display. If it's an off the shelf 3.5 digit unit, it may be set for 2:1 1/3 modulation. So for digits and icons you may need more pins than you've calculated. If you do find a 3.5 digit 4:1 display, let me know ;-)

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I've used Standish for custom LCD's several times---very reasonable prioces & great service.

http://www.hitekelec.com/standis...

Hoyt

When in the dark remember-the future looks brighter than ever.   I look forward to being able to predict the future!