To adjust the brightness to your preferred level on the Toshiba 40E220U, you need to access the Personal settings section of the Picture settings. Press Menu (on the TV or remote). The Menu button is the second button from the bottom of the buttons on the side of the TV. On the remote, it's the button above Eject and to the left and below the left arrow key. Use the Left/Right arrows to select the Picture icon. Press the Up/Down arrows to navigate this sub-menu. To select an item, press Enter. The Picture Settings is the second item from the top in the Picture menu. Once highlighted, press Enter. Then navigate to the Brightness line, press Enter. Use the Left/Right arrow keys to adjust the brightness. (Note: you may need to adjust the contrast as well. That is a separate option.) Use the arrow keys to highlight Done after adjusting the brightness. Then press Enter to save. If you select Reset and press Enter, the TV will return to the previous settings. You may also need to adjust the Mode (one line above Picture Settings) to Preference instead of the Movie or Standard mode.
You can find this information in the manual which is available here: https://support.dynabook.com/support/modelHome?freeText=3259132
. My file history gave the direct link of https://content.us.dynabook.com/content/support/manuals/userguides/su3221447/GMA300011011_CCFL_11Dec08.pdf for the manual. Most of the information is on page 72. However, the use of the TV and remote buttons is described on page 42; this is towards the end of the summary of the Menu layout.
I hope this helps.