Rainbow colours down the screen

If you wish to get some details; check the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.

Degaussing thermistor failed. Replace it. Check and replace the CRT base socket. This could be cause this fault too. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
http://electronicshelponline.blogspot.com/
Type in this key phrase " my service table today " in the search box at the top right of the display window of the home page, to get gathered some pages which has the details of practical experiences to the author of that site.

1. Verify/rule out the graphics card by connecting to an external monitor.

2. Proceed to replace the video cable or LCD. The cable is much cheaper to replace first and is the more likely cause if the screen hasn't suffered physical damage or impacts.

When you say 'rainbow look', do you mean vertical coloured lines on the screen? If so, then you will have a faulty Tcon. Could you get a snapshot of the fault and post it on here please then we can identify the problem more easily.

the light tunnel is collapsing and needs replacement.

you should change the display for your phone

Discoloration of this sort is caused by magnetism. All CRT TVs (like yours) have a de-gaussing coil around the picture tube that de-magnetizes the screen (more specifically the shadow mask) every time you turn it on. It is likely that the circuit that controls this coil is at fault. There is probably a cold solder joint where it connects to the main circuit board.

The other scenario is that someone (small child generally) has run a magnetic object very near to the screen, magnetizing the shadow mask (inside the picture tube) and causing a rainbow effect. This is less likely if the rainbow effect is a nice even circular shape. Generally if it's been magnetized by a magnet as described the discolored areas will appear blotchy.

In short, if you have some electronics skills, get in there with your soldering iron and touch up the connections to the de-gaussing coil. If not, find someone who does.

How can I fix rainbow colour screen and double view?

It could be convergence problem.