How to enhance the brgightness of LCD (ILI9328 based controller)

Hi all,

I am working on STM32 to display some bmp images on a LCD (ILI9328 based controller) and I have an issue regarding the brightness: the quality is not good enough. I am thinking to do some gamma correction and I have found this application note about the ILI9328
https://wenku.baidu.com/view/273a72de5022aaea998f0f89.html
But I didn't understand what does mean "CPT Panel", "CMO Panel", "AUO Panel", "Hitachi Panel",....
soI don't know in which case am I.
Do you have an idea what does mean this stufff "CPT Panel", "CMO Panel", "AUO Panel", "Hitachi Panel",...?
Do you know how to procedure to enhance the LCD brightness quality?
Thanks in advance.

MCU Lüfter

- - - Updated - - -

lowpowermcu said:

Hi all,

I am working on STM32 to display some bmp images on a LCD (ILI9328 based controller) and I have an issue regarding the brightness: the quality is not good enough. I am thinking to do some gamma correction and I have found this application note about the ILI9328
https://wenku.baidu.com/view/273a72de5022aaea998f0f89.html
But I didn't understand what does mean "CPT Panel", "CMO Panel", "AUO Panel", "Hitachi Panel",....
soI don't know in which case am I.
Do you have an idea what does mean this stufff "CPT Panel", "CMO Panel", "AUO Panel", "Hitachi Panel",...?
Do you know how to procedure to enhance the LCD brightness quality?
Thanks in advance.

MCU Lüfter

Click to expand...

I want just to add that the reference of my LCD is "MR028-9325-51P-TP-A"

When you say "brightness" do you actually mean "contrast" ?

Possibly there is a voltage somewhere in your display which needs to be adjusted to get the proper contrast. Some reference voltage ?
I am unable to view the specs sheets, so just guessing here.

cheers!

rohitkhanna said:

When you say "brightness" do you actually mean "contrast" ?

Possibly there is a voltage somewhere in your display which needs to be adjusted to get the proper contrast. Some reference voltage ?
I am unable to view the specs sheets, so just guessing here.

cheers!

Click to expand...

Hi rohitkhanna,

As you can read in page 86 the ILI9328 datasheet:
https://www.adafruit.com/datasheets/ILI9328.pdf
There is three types of adjustement in 10 registers !!!!:
1. Gradient adjustment
2. Amplitude adjustment
3. Fine adjustment
And I don't know which one should I tune to enhance the contrast.
In the datasheet, I didn't find a voltage to adjust the contrast.
Perhaps it is Vci, vregout!!!

Thanks in advance.

MCU Lüfter

lowpowermcu said:

Hi rohitkhanna,

As you can read in page 86 the ILI9328 datasheet:
http://www.adafruit.com/datasheets/ILI9328.pdf
There is three types of adjustement in 10 registers !!!!:
1. Gradient adjustment
2. Amplitude adjustment
3. Fine adjustment
And I don't know which one should I tune to enhance the contrast.
In the datasheet, I didn't find a voltage to adjust the contrast.
Perhaps it is Vci, vregout!!!

Thanks in advance.

MCU Lüfter

Click to expand...

Hi all,

I have some progress and I want to share it with you.
I have downloaded some test images from http://www.lagom.nl/lcd-test/
and I started changing the value of all regissters till I find that Power Control 3 register R18 and Power Control 4 register R19 have impact on LCD contrast. In my case, I find that R18 to 0X0018 and R19 to 0x1000 is the best configuration.
Hope that helps you.
Any suggestion thanks to share.

MCU Lüfter

Checkout Figure 40 Relationship between GRAM Data and Output Level

maybe that's it. Who knows ??? 106 page hi-tech manual. You kiddin' me ?

cheers !!

rohitkhanna said:

Checkout Figure 40 Relationship between GRAM Data and Output Level

maybe that's it. Who knows ??? 106 page hi-tech manual. You kiddin' me ?

cheers !!

Click to expand...

Hi rohitkhanna,

Figure 40 gives the Source Output Levels in function of GRAM data

""106 page hi-tech manual. You kiddin' me ?"" I didn't understand you point.

MCU Lüfter