Where can I find displays similar to Peugeot console LCD's?

[VinzC]

Hi.

My car includes an LCD display which I like very much as it is clearly visible in the bright sun as well as in pitch black night. It's an LCD display with orange writings and the background is black — I'm not sure "background" is really appropriate.

When the Sun shines on it the display looks as if you had a punched, black cardboard over an orange sheet, which makes you sort of wonder if it's electronics at all (just to illustrate what I'm writing, of course). Anyway the black surrounding turns totally opaque and the orange reading is perfectly visible, no squint needed. Here's what it looks like in moderate light:



I'm curious how they're made and what peculiarity makes them so visible in plain, bright light for I hold LCD not very bright-light-friendly. Then I'd also like to know if LCD displays (matrix or digit) are available with that technology, possibly in other colours too.

Thanks in advance

[CJay]

Same tech as the Vauxhall MID and TID modules I think.

But!

The later Vauxhalls and Fords also have full colour graphics displays that are impressively visible in bright daylight too.

[VinzC]

@CJay do you have any reference I can look for? I know nothing of those displays in fact... (shame, I know.)

[mikeselectricstuff]

Don't know for sure but I'd guess these may be monochrome TFT's

I'm sure an LCD manufacturer would make some for you with a MOQ of maybe 10K and a few K tooling.

[helius]

Sunlight readable LCDs are "transflective" types. transflective + amber should give you enough hits to find some displays.

[VinzC]

Don't know for sure but I'd guess these may be monochrome TFT's

I'm sure an LCD manufacturer would make some for you with a MOQ of maybe 10K and a few K tooling.

Well, alas our production quantity won't ever be as big, mostly a few units a year.

[amyk]

Could it be a VFD with an orange filter in front of it?

[Buriedcode]

Theres a number of techniques used over the years to improve both the contrast and 'readability' of negative STN/TN displays in bright conditions/sunlight. 

These include DSTN, FSTN, black mask between pixels (instead of just relying on the crossed polarizers), LC doping to match backlight colour, lambertian/antiglare surface treatment and circular polarizing filters. 

I too have noticed some cars that still have the monochrome displays can be rather impressive, very much like a modern high contrast (>400:1) TFT but even better in sunlight and I'm sure that these employ some, if not many of the above techniques.

I'm unsure if these displays are in fact transflective in terms of any partially reflective backing film, or given the lack of space restrictions they simply rely on the dyed liquid crystal and a large white plastic (hollow) blacklight reflector/housing.  That would mean any incident light would be scattered by the anti-glare surface, through the display, scattered again randomly around the backlight housing and back out the display, again through the active pixels - it would mean even in bright conditions it can maintain its contrast, even though the incident light is far brighter than the backlight, where most standard FSTN negative displays completely wash out.

If you're just 'tinkering' out of curiosity  it can be quite fun buying some cheap monochrome displays and hacking backlights.  Another 'trick' is to use a circular polarizer over the top: light exiting the display, already polarised, gets twisted, say left handed.  Any incident light going into the display is also twisted left, but when reflected off the various layers of glass, becomes right handed, and so blocked - these filters only let light through 'one way', any that has been reflected is blocked.  You can check this out in a mirror by putting the film over one eye - you can see through it to see your reflection, but in the reflection it appears black. https://drj11.files.wordpress.com/2010/10/img_1774.jpg

Sorry, displays are my thing :/

[matkar]

I think you give too much credit to this LCD. In a car LCD is never directly exposed to sunlight since it is always mounted deeper in the dashboard. With direct sunlight you wouldn't be able to read from this LCD. Negative type LCDs are not recommended for outdoor use. Generally you want reflective or transflective type for direct sun exposure.

[VinzC]

Sorry, displays are my thing :/

Why be sorry? I always enjoy a nice and detailed information like this. Thanks again.

I think you give too much credit to this LCD. In a car LCD is never directly exposed to sunlight since it is always mounted deeper in the dashboard. With direct sunlight you wouldn't be able to read from this LCD.

Buahahahahaha... So I shouldn't believe what I actually *saw* myself with my naked eye, right?

Good trolling.

[matkar]

Ad why should I believe you? Attach a picture with sun shining directly on the screen please.

[Cerebus]

Sorry, displays are my thing :/

Why be sorry? I always enjoy a nice and detailed information like this. Thanks again.

I think you give too much credit to this LCD. In a car LCD is never directly exposed to sunlight since it is always mounted deeper in the dashboard. With direct sunlight you wouldn't be able to read from this LCD.

Buahahahahaha... So I shouldn't believe what I actually *saw* myself with my naked eye, right?

Good trolling.

You can't always trust your eyes; especially when it comes to judging colour or illumination levels from relative contrast, cf:  https://en.wikipedia.org/wiki/Checker_shadow_illusion. Or when it comes to Gorillas joining in basketball games, http://www.theinvisiblegorilla.com/videos.html.

[TheBay]

I tend to agree with VinzC's observations.

I have noticed this myself in a few vehicles, my BMW heater control panel and Dashboard display is the same, it's always very visible with lovely contrast and a few previous cars have been similar.
One thing that will throw the perception and location theory out the window is whenever I have replaced a factory fitted radio with a off the shelf one, the display on any of the off the shelf models are awful in sunlight, regardless of being TFT/OLED/Traditional LCD. Same with any PDA/Phone used in the same location.

I do wonder if it's to do with the filters, LCD technology or polarization, as I wear polarized sunglasses when I drive and any of the factory fitted LCD panels will go complete black with the sunglasses on.
Other LCD displays have a rainbow effect or just fade slightly.

Something also looks different about the automotive LCD's, they almost have a blurry appearance to them. On one of my cars as it warmed up the display got less legible, it wasn't a connector or electrical fault it was something to do with the chemical used in the display.

[Buriedcode]

That is most likely the fact that LC displays have limited temperature ranges.  This range is further reduced when compensation films are used (FSTN), so in colder conditions the compensation actually makes it worse.

The 'fuzzy' appearance could well be the anti-reflective coating/face plate.  I have some extremely old (and terrible contrast) G2446 LCD's that are pretty much matte.  Despite a contrast of a measley '5' I can still read it when angled to reflect a bright window - the backlight makes little difference here, but even (non anti-reflective) TFT's wash out under those conditions.

If you've ever worked on a dashboard you'll notice many of the built int displays don't use the standard flat light-pipe backlight but rather a hollow plastic housing.  There's no need to make it thin, so they use the space for a large white reflector with however many LED's/bulbs they need.  This generally means the backlight can be much brighter and has a wider viewing angle, also much more even as its not restricted to an etched slab of acrylic to distribute light.  Perhaps I am going OTT here, there still don't have the contrast of a good TFT, but I, like the OP, am still impressed at how visible and clear they are.  Of course they have to be for safety reasons.

After market or 3rd party stereos probably use an OEM LCD module with a built in lightpipe (flat) backlight.  There's only so much room to put LED's in those so it limits the total brightness.  Not only that but they probably use cheaper STN displays too with limited viewing angle - standard consumer grade stuff.

The fact the display is black when you wear glasses is just bad luck that the plane of polarisation of the display is the same as your glasses It could well be the cheaper displays are just standard linearly polarised (like *all* LCD's) but without a quarter waveplate to turn that into circular.  And if your glasses are also linearly polarised.. it gets complicated dealing with circular polarisation, because of the way circular polarisers work. Check out this demonstration - it still twists my melon.

http://physics.stackexchange.com/questions/70384/are-these-sunglass-lenses-linearly-polarized-or-what

[cs.dk]

If you can guess the displaytype just from pictures, i've got an defective one from a Peugeot 307 i can tear apart. The display is completely black, when the 3 1,2W bulbs are missing, so it is not a reflective display.

[Pjotr]

Ad why should I believe you? Attach a picture with sun shining directly on the screen please.

It is not a reason but a hint: I noticed the same as Vinzc and wondered how they archive such a high contrast at normal back lighting as well with direct incident sunlight.

My Peugeot has a bit different display than shown, with hard symbols and 14-segment characters (not dot-matrix). Late at day the sun can be directly at the display at almost 90 deg. The black is still inky black and the symbols look like cut out with a white opaque sheet some mm behind. However the amber colour fades to near white / light brown. So it appears the opaque back sheet is white and lighted amber from behind.

[SL4P]

How about a circula polarising filter in front?
Apart from the filters within the display, this wil help reduce reflected glare off the glass.

[VinzC]

My Peugeot has a bit different display than shown, with hard symbols and 14-segment characters (not dot-matrix). Late at day the sun can be directly at the display at almost 90 deg. The black is still inky black and the symbols look like cut out with a white opaque sheet some mm behind. However the amber colour fades to near white / light brown. So it appears the opaque back sheet is white and lighted amber from behind.

You've described in better words than I would have chosen exactly what I have observed. Just that I never had/took the opportunity to tear one down so I was curious if devices with similar characteristics exist outside the automotive world and are globally available. I found some sunlight-readable displays I'd like to try. They don't necessarily have to behave like the one in my car so if they produce an acceptable result, well...

[Buriedcode]

I think you should be careful not to confuse LCD segments with symbols etched out of plastic, with white plastic moulding and a single LED per 'symbol' - pretty much how seven-segment displays work.

The photo in the first post is clearly an LCD, where-as many lights/inidicators in vehicles are just moulded panel indicators with LED's or filament bulbs behind each one.  There's a thick black mask over it all to increase the contrast, but in full sunlight these segments  - which are just diffuse epoxy poured into moulds - can glow making it appear like they're all lit.  This is where circular polarisers work extremely well, light that enters is strongly attenuated when it leaves, where-as light that originates from the display can leave, albeit with 50% loss (<10% loss if using 3M's polarising reflector film, great stuff!).

Sadly I've made my own using moulds to make the white plastic housing (the white plastic is a lambertian surface, scattering light making it much more even) filled with diffuse epoxy.  The walls separate the symbols so there's no bleed between them and a blank PCB just with SMD LED's does the job.  Its a hell of a lot of work and of course not very flexible, but for static symbols it can look rather nice.  Wasn't for a job, purely curiosity and bordom 

An example, aside form the obvious 7-seg displays and bargraphs are things like these: https://selectronic.co.uk/wp-content/uploads/2015/03/small-led-display-set-top-box-600x600.jpg?779920
with each segment being its own chamber and diffusing epoxy poured in.  Light from almost any angle shone on the underside makes the entire segment light up because it is scattered so well.

Sure high contrast TFT's are the most versatile, but there's still a place for these LED glyphs, wider temperature range, simple and intuitive, no software drivers or variable LCD drive to go wrong.  Its just for small runs its far too expensive to go custom.  Its probably why VFD's are still about, a bastard to drive but excellent viewing angle and contrast.


In terms of finding a display module with a very high contrast (and without resorting to a TFT) these look pretty good: http://www.data-modul.com/us/news/current-news-overview/current-news-content/items/high-contrast-lcd-displays-for-industrial-applications-467.html

I am currently using the cheaper version of this for a project: https://www.adafruit.com/product/2088  Its a TFT, so 'cheating', but I am thoroughly impressed with its contrast and how readable it is in bright light.  Not great in sunlight, but I'm running the backlight at 10mA.  I have another 20 on order for a small panel, with each display having its own symbol. Not bad for £3 a pop.

[ivan747]

Kias from the 2010 period seem to use a diagonal polarization.


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[Zero999]

Perhaps the windscreen has a polarising filter opposite to the LCD's filter?

[LazyJack]

Perhaps the windscreen has a polarising filter opposite to the LCD's filter?

Most likely. The same display is used in Citren cars, but with bright background. See: http://www.autorevue.cz/obrazky/2005/11listopad/c4vtr/int26.jpg

BTW. The Citroen C4 has a central LCD display, which not only has backlight, but also translucent from the back, so you can see it in any brightness.

 

This is a quite smart solution.