Here is link for downloading 用戶手冊.

You can try to download the manual from:

http://manualspace.com/2002-camry-owners-manual.htm

"燈的兩側為正負符號" It is called "Discharge Warning Light".
This light warns that the battery is being discharged. If it comes on while you are driving, there is a problem somewhere in the charging system.
The engine ignition will continue to operate, however, until the battery is discharged.
Turn off the air conditioning, blower, radio, etc., and drive directly to the nearest Toyota dealer or repair shop.

If I were you, I would check the wiring in charging system first to see if they are connected properly and if alternator belt is tight. Another possible cause is the alternator is becoming weak, which requires to be replaced soon.

If the light comes up often, you'd better to have it checked soon.