How increase contrast of LCD Volcraft DPS 4005

[asrock70]

I've been using a Voltcraft DPS 4005 power supply for many years and all this time I've been annoyed by the poor LCD visibility.
Today the cup overflowed and I disassembled the miracle of German engineers, which is produced and designed by Chinese comrades.

To begin with, if you look at the LCD from below, the contrast is excellent, not much when viewed from the front, but readable, when viewed from the top you can hardly see anything.

The LCD is soldered to the PCB and the entire LCD is controlled by the Universal LCD driver PCF8576,
VDD in +5V
Vss=0V GND
VLcd=0V according to the PCB and the diagram, there should be some voltage from the divider R1/R2 (0-5V), in real R1 miss and R2 replaced the wire.

Am I correct that I could apply a negative voltage, say -600mV to the VLcd and thereby increase the contrast of the LCD?

 

[FvM]

The observed view angle is caused by a inappropiately orientated polarization filter and can't be changed adjusting control voltage.

 

[carpenter]

You are right, on the other hand, the black level can be influenced by the voltage, and a more pronounced black is more visible even with a bad filter.
With LCD, the contrast cannot really be influenced other than by the excitation voltage

 

[D.A.(Tony)Stewart]

Adjust bias and verify if improved.

The polarization filter is optimized for a Horizontal flat surface in front of you.

 

[FvM]

The polarization filter is optimized for a Horizontal flat surface in front of you.

Most reflective LCD displays that I know are specified with "6 O'clock viewing direction".

 

[D.A.(Tony)Stewart]

Most reflective LCD displays that I know are specified with "6 O'clock viewing direction".

which means the same but with a certain elevation angle.