how to avoid glare in scrolling message display

[binu.kr]

iam making a 10 character 5*7 scrolling led display using pic 16f877a....but in night it glows with glare ,can u please give me a solution to overcome this problem,glare is in next line onlymeans coming line, iam using shift register to give positive voltage to led,......pls help me to solve this problem


my display loop is



for(p1=0;p1<50;p1++)
{
V2=temp5[P1];
#ASM

BCF PORTC,3...clk to shift register
NOP
NOP

CALL DELAY1
BSF PORTC,3
MOVF V2,0
MOVWF PORTD
CALL DELAY1
#ENDASM

}

OUTPUT_BIT(PIN_C0,0);
#ASM
CALL DELAY1
#ENDASM


iam using asm inside because while iam using c code for display loop more glare is coming


my c loop,spi ptrotocol used to write value 0x01 to shiftregister

for(p1=0;p1<50;p1++)
{

OUTPUT_BIT( PIN_C3,0); shift register clock
DELAY();
OUTPUT_BIT( PIN_C3,1);
output_d(temp5[p1]);
DELAY();
}

OUTPUT_BIT(PIN_C0,0);
DELAY();
thank u ......

[libor]

I suppose your problem is more hardware related. Your LEDs (line drivers) not turning off quickly enough.
Do you use driver FETs ? What is the circuit ? The cause can be, you're not turning off (and on) the FETs fast enough. The gate acts as a capactor and if you do not apply enough inrush current, and discharge current, it results as a slow turn on/off on the output side (LEDs), which can explain the afterglow effect you experience.
You can mitigate the problem with inserting some idle time (with all drivers turned off) when changing rows/columns, though it would result a lower brightness overall.

[Guest]

Thanks for ur valuable reply. Some more problems in my circuit. Please check this glare is happening to the coming led, i can see glare before the actual letter going through the led's, while i am using asm code glare will be minimised.
I am using tip122 darlington transitor. The display is 50 columns connected to tip122. The collector of tip122 is connected to shift register input via 10k resistor, and 15 rows connected to the portb and d, total 750 led's and using 1 amp transformer for driving led's. 500 mamps transfomer for driving poret and other connections. Can u please help me to solve this problem ?