Newhaven Display Forum

Newhaven Products => Graphic LCDs => Topic started by: GoldenMask on April 04, 2016, 05:22:40 AM

Title: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: GoldenMask on April 04, 2016, 05:22:40 AM
Hello,
recently I decided to use NHD-C12864WO-B1TFH#-M and he has a problem with sunlight, LCD becomes very dark. I bought 100 pieces. and all have this problem. Until now I instead use BTHQ128064AVO-FETF-06-LEDWHITE02-COG and I never had such problems.
Please tell me where I'm wrong. https://www.youtube.com/watch?v=eD-o3xmkUT8

Wiring diagram.
(http://s9.postimg.org/i1ey4cvgf/lcd.jpg) (http://postimg.org/image/dsa826s6z/full/)
screen capture tool (http://postimage.org/app.php)

Title: Re: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: Saurabh_B on April 04, 2016, 05:22:48 PM
Hi,

Would it be possible to provide the date code on these displays.
Title: Re: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: GoldenMask on April 05, 2016, 04:11:25 AM
Hi,
I used BTHQ128064AVO-FETF-06-LEDWHITE02-COG
http://www.farnell.com/datasheets/1536571.pdf
for over an year

Now I have bought a quantity of 100 pcs of:
NHD-C12864WO-B1TFH#-M
http://www.newhavendisplay.com/nhdc12864wob1tfhm-p-2950.html

but it seems they have a problem fading to black when exposed to moderate to intensive sunlight. How can I resolve my problem? Is it a problem with the displays, or there is a crucial incompatibility between both LCDs? I intend to buy much bigger quantity of these displays (NewHaven) in very near future. Should I return the quantity of 100 pcs NewHaven displays to mouser.com and look for another supplier?
More:
I used Batron displays and they were able to implement 64 grades of contrast, but Newhaven displays were not able to implement any. Also if you need me to send you the initialization code that my software does to the NewHaven Displays, I will provide it.
Here I give you my colleague's Skype ID, in order to communicate with him faster and eventually resolve the problem. it is kostaki12301 (Skype).
Best regards,
and hope you are able to discuss and resolve the issue very soon.
Title: Re: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: Saurabh_B on April 05, 2016, 12:21:51 PM
Hi,

Could you please send the initialization sequence you are using for the display.
I will conduct a test here as well.

Do you by any chance have any light sensitive components on your PCB?

Could you take a picture of the back of these displays as well?

Thanks
Title: Re: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: GoldenMask on April 06, 2016, 10:19:48 AM
Hi,

Here are the photos of the back of the displays:
(http://s16.postimg.org/e4uq5vy75/20160406_174331.jpg) (http://postimg.org/image/e4uq5vy75/)

(http://s16.postimg.org/kfzxmazfl/20160406_174410.jpg) (http://postimg.org/image/kfzxmazfl/)

(http://s16.postimg.org/vgv2rbroh/20160406_174425.jpg) (http://postimg.org/image/vgv2rbroh/)

----------------------------------------------------
This device has no photo-sensitive and no photo-emitting parts (besides the backlight of the LCD screen). The PCB of the device is located behind the LCD and they both are glued to each other. There is no light entering to the back of the LCD. The only sunlight that enters is through the front panel's window: here is a photo of the front panel of the device: http://www.goldenmaskdetectors.com/detector_details.php?id=7&lang=en

----------------------------------------------------
Here is the LCD initialization procedure:
Init_LCD:
        cbi     PORTE,2         ;Reset LCD Low
        call    wait_20ms
        sbi     PORTE,2         ;Reset LCD High
        call    wait_20ms

        putcmd  $40
        putcmd  $a0
        putcmd  $a6
        putcmd  $a4
        putcmd  $a3 ; (a2) LCD Bias Set    a2=1/9 bias, a3 = 1/7 bias (ST7565)

        putcmd  $2f
        putcmd  $27

        putcmd  $81
        putcmd  $3A

        putcmd  $af
        rcall   wait_20ms
RET

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PLEASE NOTE:

There were no such problems with the previous LCD model that we were using for more than one year: (BTHQ128064AVO-FETF-06-LEDWHITE02-COG)
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Since I got some deadlines and engagements to keep I really hope you could resolve my problem and give me a solution A.S.A.P !
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Title: Re: NHD-C12864WO-B1TFH#-M problem with sunlight
Post by: Saurabh_B on April 06, 2016, 04:14:38 PM
Hello,

For the time being I would contact Mouser to set up an RMA for the displays that have the contrast fluctuations. Since you are located in Europe this would be the easiest option. Mouser will then work with us to send the displays back for analysis.

In the meantime  I will test a few samples of these displays to see if we have the same issue on our end. Testing these displays with direct sunlight will have to wait until we have better weather here.

I was wondering if you could make 2 adjustments on your initialization process:
1. Change putcmd(A3) to A2 for 1/9th bias.
2. Use a smaller value for the contrast value, 3A is almost maxed out.

On the schematic there are a few differences for the the voltage booster portion as well.

- Pin 18 is C1-
- Pin 19 is C1+
- Pin 30 should not be connected to anything.
- Pin 27 needs a voltage input, this would be set by a potentiometer. Please refer to the schematic on page 4 of the display specification (http://www.newhavendisplay.com/specs/NHD-C12864WO-B1TFH-M.pdf)
- I would also replace the 1 F capacitors with 2.2 F capacitors.

Please let me know the results of those modifications.