Electro-optical device, electronic apparatus, and transistor

An electro-optical device comprising:

• a substrate;
• and
• a transistor that includes:
• a gate electrode;
• a semiconductor film that includes a first source and a first drain;
• and
• a channel region that is formed between the first source and the first drain, at least a part of a light-shielding film overlapping with the semiconductor film, the light-shielding film having:
• a first portion that extends along a first direction;
• a second portion that protrudes from the first potion along a second direction intersecting the first direction;
• and
• a third portion that protrudes from the first portion along a third direction intersecting the first direction,
• the first portion having a first width along the second direction,
• the second portion having a second width along the first direction,
• the third portion having a third width along the first direction,
• the second portion and the third portion being formed such that the second width is smaller than the third width, and
• the semiconductor film having a first part,
• at least a part of the second portion overlapping with the first part,
• the first part having a fourth width along the first direction,
• the channel region having a fifth width along the first direction, and
• the fourth width being greater than the fifth width.