Thinkpads Forum

I have a visual disability that leaves me very sensitive to certain types of light and most computer monitors (LED based monitors make me feel sick within seconds). I have a T40 (2373-75U) that I use with dimmed screen, dark background and light text, and can use it for several hours before various neurological symptoms start to arise.

The T40 is starting to show its age. I have a wide-screen T61 which is enough for my needs as far as performance but I can't look at the screen for nearly as long as the T40, so I don't use it.

I'm not sure exactly why I can tolerate the T40 screen for so much longer (screen resolution, lower being better? Something about the CFLs? Another factor?) Whatever the reason, I'd like to upgrade while using the same screen if possible.

1) Is it possible to get a 14" XGA T61 and replace the screen with the 14" XGA screen from my T40?
(Maybe I would get lucky and be able to tolerate an XGA display on a T61, but before I buy one on my limited income, I'd like to know if I have the option of using the T40 screen.)
2) Is a T61 Frankenpad with max RAM and SSD my best option for last-great-thinkpad construction assuming I can use my T40 screen?

Thank you.

A T40 screen will not work in a T61 without soldering a chip and edid flashing. This is because many of the T4* screens (and prior thinkpads) relied on the cable to output images correctly. There are some T43 late model screens that will work without modification, but they are very rare. You cannot use a T4* LCD cable in T6* models.

If it's an LG LP141X14(A1) [FRU 11P8354], it *should* work. It must be XGA (as the XGA displays don't have an EDID chip, apparently). The inverter and cable from the T61 would need to be used.

brchan wrote:A T40 screen will not work in a T61 without soldering a chip and edid flashing. This is because many of the T4* screens (and prior thinkpads) relied on the cable to output images correctly. There are some T43 late model screens that will work without modification, but they are very rare. You cannot use a T4* LCD cable in T6* models.

I'm not entirely sure what you mean when you say 'relied on the cable'. What actually happens is that the higher resolution displays need an EDID chip, and lenovo has some blacklisting in effect. So anything beyond XGA (can) become problematic unless you feel like doing heavy modifications. And of course, the T43s with intel chips couldn't push high resolutions (a limitation of the intel graphics chip).

14.1" T4x/R5x with Intel graphics only supports XGA.
15" T4x/R5x with Intel graphics supports XGA and SXGA.

14.1" T4x/R5x with ATI graphics supports XGA and SXGA+.
15" T4x/R5x with ATI graphics supports XGA, SXGA+, UXGA and QXGA.

All T4x/R5x resolutions need their own cable and inverter.
T6x/R6x use different cables/inverters from T4x/R5x.

All 14.1" and 15" 4:3 T6x/R6x machines (whether Intel/ATI/nVidia) support XGA, SXGA+, UXGA and QXGA

14.1" and 15" XGA screens from T4x/R5x will work in T6x/R6x without screen mods.
Any other T4x/R5x screens will need an EDID chip to work in a T6x/R6x.
T6x and R6x cables can use any resolution, but T6x cables are different from R6x cables.

Complicated?
Yes, but once you know...

micrex22 wrote:I'm not entirely sure what you mean when you say 'relied on the cable'.

On the T4x series, the LCD cables for XGA, SXGA+, and UXGA are all different.
Each type of cable has a different configuration, which the system board detects, and sets the appropriate display resolution.

This is what he meant by 'relied on the cable'.

There's an old thread on the T4x (or R5x) section where the OP managed to modify the cable-- IIRC from XGA to SXGA+.

Have you tried an IPS (flexview) screen?
One property is that a black background really is deep black, in contrast to a TN screen (the technology used in your XGA) where a black background has a sheen. Based on your favoured settings I suspect you'd prefer this even to your T40 XGA. I suggest you first see how you respond to the screen before spending a lot by getting your eyes on either of the following thinkpads with 15.0" screens: A31p, T40/1/2/3p, R50p, T60p.
Maybe you could meet up with a board member who lives in your vicinity or buy one of the old models cheaply.

Where your XGA "beats" the IPS screen is that it has a lower resolution. You would have to test to see the relative importance of character size versus light transmission quality. I'd say the latter is more important to you based on your post. Your 14.1" XGA has 91 dpi (dots per inch), a 15.0" SXGA+ 117 dpi and a 15.0" UXGA 133 dpi. So if your font uses a fixed number of pixels the same character would appear progressively smaller.

If you find the IPS to be a panacea, you have many options given that the T40 has sufficient power for your needs and you don't need to break your piggy bank. At the bottom of the spectrum you could put the appropriate screen in a 15" T60 with integrated graphics.

Obtaining a screen can be tricky, that's the raison d'etre of the sticky thread in this forum, which should be consulted.

You would want to avoid the LED backlit 15.0" IPS screen (there is no chance you'd get this by accident) since it can't be dimmed to the same levels as those with a ccfl.

In response to your question (2):
If you just want to stick with your T40 XGA screen you don't need a T61 "frankenpad", the 14.1" standard screen T61 is all that's required.

unixed wrote:You would want to avoid the LED backlit 15.0" IPS screen (there is no chance you'd get this by accident) since it can't be dimmed to the same levels as those with a ccfl.

Yes you can.
I have done about 70 of those LED-screens and each single one dims (I think it is 15 steps) down to virtually OFF.
That is/was for T60 Frankenpads. See http://theboardroom.info/led_mod.htm

When trying such a LED-screen on the T4x, it only has 7 steps and LED functions only on steps 5-6-7. Any lower and it's OFF.

unixed wrote:Have you tried an IPS (flexview) screen?
One property is that a black background really is deep black, in contrast to a TN screen (the technology used in your XGA) where a black background has a sheen.

...

Where your XGA "beats" the IPS screen is that it has a lower resolution. You would have to test to see the relative importance of character size versus light transmission quality.

I haven't tried an IPS screen but would like to. I found recently when trying a different T61 that it's the light quality and intensity, far more than the screen resolution, that causes me the most problems. I looked at a full brightness 1400x1050 (I think) T61 screen for roughly one minute, with very little reading, and felt ill for a couple of hours after.

So there's something about the quality of the light with my T40 that makes it easier to tolerate. It isn't just related to intensity since I can use a T61 on the dimmest setting, which is darker than the T40, and still feel ill faster.

1) Could this have something to do with CFL dimming/ageing over time?
Or some difference in manufacturing or use of the CFL between the time the T40 and T61's were produced?
2) If it might be related to CFL ageing, could I take the CFL from the T40 and use it in a T61?
3) Does the sheen from a TN screen come from the backlight? If it does, then maybe an old CFL plus a IPS or ASV screen might help to reduce that light and make it more tolerable for me.
4) I've read that some displays use a kind of pixel strobing to simulate more colors than the display can produce. This causes headaches for some people due to the flicker. I'm very sensitive to flicker. More speculation: maybe my T40 doesn't have this strobing but the T61's that I've tried do have it?

Thank you all for the suggestions and comments.

For the A2x/A3x/T4x/R5x/T6x/R6x series ONLY 15" screens were available in IPS from IBM/Lenovo.
There is a Sharp 14.1" UXGA screen, which needs a small cable-mod, but UXGA in 14.1" is really pushing it.
AFAIK only a handful have ever been fitted in a 14.1" T6x.

If a screen is too bright for you, why don't you turn it down a bit?

RealBlackStuff wrote:If a screen is too bright for you, why don't you turn it down a bit?

I already use the T40 at one step up from the lowest brightness setting, with light text on a black background. With the T61's that I've tried even the lowest brightness setting still leaves me feeling ill fairly quickly. This is why I think my problem has something to do with the quality of the light, while the greater intensity just causes my symptoms to worsen more quickly.

The problem is more with your eyes.
Black on a white background is what most people use (such as this line).
White on a black background has never appealed to most people, it goes from ALL to NOTHING.
Turn your background into a dark(ish) grey, such as here on my website: http://theboardroom.info/sata_mods.htm
Notice the pure black column on the left, and the grey background with white text next to it.

RealBlackStuff wrote:The problem is more with your eyes.
Black on a white background is what most people use (such as this line).
White on a black background has never appealed to most people, it goes from ALL to NOTHING.
Turn your background into a dark(ish) grey, such as here on my website: http://theboardroom.info/sata_mods.htm

I've tried many different color schemes on different types of monitor (CRT, LCD, fluorescent and LED backlight etc.) White text on a black background with dimmed screen works best for me (so it's effectively gray text on a black background). My symptoms arise at various rates across different monitors even with an identical color scheme and darkened monitor settings.

The effect is neurological rather than eye related. A neurologist I spoke to about this problem said that he had patients that had to stop using monitors because they couldn't find any medications to relieve their symptoms.

patj wrote: 1) Could this have something to do with CFL dimming/ageing over time?
Or some difference in manufacturing or use of the CFL between the time the T40 and T61's were produced?
2) If it might be related to CFL ageing, could I take the CFL from the T40 and use it in a T61?
3) Does the sheen from a TN screen come from the backlight? If it does, then maybe an old CFL plus a IPS or ASV screen might help to reduce that light and make it more tolerable for me.
4) I've read that some displays use a kind of pixel strobing to simulate more colors than the display can produce. This causes headaches for some people due to the flicker. I'm very sensitive to flicker. More speculation: maybe my T40 doesn't have this strobing but the T61's that I've tried do have it?

The first thing to realise is that you'll have to give up your T43 screen and its backlight eventually, and you'll be better off finding an alternative before that is necessary. All backlights, just like other lights, eventually fail.
Screen construction is more complex than a monolithic "screen" with a backlight. The screen consists of multiple layers, some properties of which can change due to UV light exposure, for example. You've become comfortable with a particular combination of aging backlight and screen. The backlight will fail, it's only a question of when.

So the answer to
(1) is yes,
(2) is yes, you can transplant the ccfl, but it is not easy, you'll probably have to pay someone to do it so that you don't damage it (or practice with a dispensable one first); you probably won't be happy with the results because you want the aged screen layers too; the backlight will fail eventually.

The answers to (3) and (4) require more detailed knowledge of the screen structure, there's plenty of material on the web.
Simply put, you have the backlight shining through a pixel, just like shining a torch through a coloured thin plastic bag. So you can see what happens for colours and whites.
But with blacks it has to block the incoming light.
TN and IPS screens operate differently in general, but of particular interest here, with regard to blacks.

From one of the IPS screens datasheet:
Display mode Normally Black

With a TN screen, polarised light comes in from the backlight, follows the "twisted" (TN : twisted nematic) liquid crystal waveguide and out through the orthogonally polarised front layer. Since all of that happens by default because of the mechanical properties of the two layers adjacent the liquid crystals, a TN screen transmits light by default. To block light, you apply an electric field which disrupts the liquid crystal waveguide.
So, summarising the above, a fictitious TN datasheet would read:
Display mode Normally White

So the answer to
(3) is yes, but the difference with an IPS screen is due to how it functions -- for example, with a TN screen you have to apply an electric field to block light whereas with IPS you apply the field to transmit light.

The answer to
(4) is probably no. You are either referring to how many bits get used for Red, Green or Blue pixel components or how brightness is controlled by switching a backlight off and on at a certain frequency, but the first is the same for the two models and the dimming method is likely to be so too.

In summary, your current setup is not sustainable, but I think you can do better, read my first post.

Stick with your grey text on a black background. It is the sensible thing whether or not you are aligned with the majority -- UNIX, dos, windows command prompt, linux virtual consoles ... not everyone appreciates having a torch shone in their eyes when reading.

patj wrote: I've tried many different color schemes on different types of monitor (CRT, LCD, fluorescent and LED backlight etc.) White text on a black background with dimmed screen works best for me (so it's effectively gray text on a black background).

You don't have to use a severely dimmed white to simulate grey, use grey instead!
For example, if you're using a xterm under linux, you can try
UXTerm*.background: black
UXTerm*.foreground: lightgrey
in your ~/.Xresources file.
Whatever your operating system, there'll be some way of doing that and some place on the web telling you how.

RealBlackStuff wrote: Yes you can.
I have done about 70 of those LED-screens and each single one dims (I think it is 15 steps) down to virtually OFF.
That is/was for T60 Frankenpads.

When the screens are off the IPS is equivalent to the TN.
So what's of interest to the OP is the granularity of control -- for each click up I assumed the led-backlit IPS would get brighter faster than the ccfl-backlit ones, based on the comparative photos on this forum, the characteristics of led's, etc.
Basically if the LED screen is brighter and the levels are discrete the ccfl-backlit IPS screen would give finer-grained control, especially where needed in the dimmer range.

Checking to see how much brighter the LED-lit HV150UX2-100 is compared to the ccfl-lit ones I was surprised to find the datasheets state:

Parameter --- | -------- | Min. | Typ. | Unit
-----------------------------------------------------
Center
Luminance of |1 Point | 170 | 200 | cd/m^2
White

for all models, whether LED or CCFL-backlit.
Some people may be more familiar with "nits" instead of "cd/m^2".
The difference between them shows up here:

Parameter ----------------- | Min. | Typ. |
------------------------------------------------
Luminance Contrast ratio ---- 500:1 (HV150UX1-100)
Luminance Contrast ratio ---- 500:1 (HV150UX1-101)
Luminance Contrast ratio 350 500 (HV150UX1-102)
Luminance Contrast ratio 500 600 (HV150UX2-100)

and here is note (2) referring to Luminance Contrast ratio:

2. Contrast measurements shall be made at viewing angle of = 0 and at the center
of the LCD surface. Luminance shall be measured with all pixels in the view field
set first to white, then to the dark (black) state .
Luminance Contrast Ratio (CR) is defined mathematically as CR = Luminance when
displaying a white raster / Luminance when displaying a black raster.

You can't believe everything that's printed/published.
You'd have to see such a machine "in person" to observe the HUGE differences between CCFL and LED version.
Methinks someone took the CCFL datasheet, made a few minor changes and additions, and saved it as LED.

unixed wrote:The first thing to realise is that you'll have to give up your T43 screen and its backlight eventually, and you'll be better off finding an alternative before that is necessary. All backlights, just like other lights, eventually fail.

I've been looking for alternatives for more than a decade. The T40 is the best I've found, by far. I know its lifespan is limited which is why I try keep trying alternatives. I know for certain that anything that uses LED lighting isn't an option.

Sunlight and incandescent don't cause any problem for me so I'm going to try a desktop LCD with the case and lighting removed, and use a couple of incandescent lights behind it to see how I react.

unixed wrote:From one of the IPS screens datasheet:
Display mode Normally Black

Thank you for the detailed explanation, it was helpful. IPS and ASV are now on my list of screens to try.

unixed wrote:You don't have to use a severely dimmed white to simulate grey, use grey instead!

Dimmed white is better for me than grey with higher brightness. The dimmed screen also reduces colors in icons, photos on web sites etc. so they're easier to tolerate.