Problem with bleeding backlight from a 1.77" 128x160 TFT

I bought two graphical TFT displays for a project:

The first one (1.8"): 1.8 inch Spi TFT Display ST7735 with 128 x 160 pixels – AZ-Delivery

The second one (1.77"): 1.77 inch Spi TFT Display 128x160 Pixel ST7735 2.7V - 3.3V – AZ-Delivery

I connected them to an Arduino Duemilanove, loaded up the "Adafruit SD7735 and SD7789 library", and the graphicstest example sketch. The 1.8" inch display works perfectly, but the 1.77" is giving me trouble. The sketch runs fine, and the display shows what the sketch is sending, but there seems to be a light bleeding out of the top of the display and the colors show less contrast especially in the top. Also, there are pale vertical lines going from the top of the display to the bottom whenever something is displayed.

My first thought was that I have a faulty display. But I don't think that is the case because when the sketch gets to the loop() part where the screen is inverted every 500ms while the media buttons are displayed, the bleeding light from the top disappears and the contrast becomes perfect. But the bleeding returns when something new is drawn on the screen.

I tried looping only that part of the sketch where the "Lorum ipsum..." text is sent:

while (true)
{
  // after this block of code the text is shown with bleeding from the top
  tft.fillScreen(ST77XX_BLACK);
  testdrawtext("Lorem ipsum ...", ST77XX_WHITE);
  delay(1000);
  
  // after this the bleeding disappears and the contrast is perfect
  tft.invertDisplay(true);
  delay(20);	// this must be at least 20ms for this "trick" to work reliably
  tft.invertDisplay(false);
  delay(1000);
  
  // the circle is drawn and the bleeding returns
  tft.drawCircle(30, 30, 30, ST77XX_WHITE);
  delay(1000);
}

Does anyone have any ideas?

bump+same issue

HEYA
just connect tft to 5v....error solved

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.