Tilt sensor

A tilt sensor comprising:

• a mount board;
• a cover plate spaced from the mount board;
• a light emitting element and a pair of light receiving elements arranged on an obverse surface of the mount board;
• a case arranged between the mount board and the cover plate for accommodating the light emitting element and the light receiving elements, the case being formed with an inner rolling space surrounded by the light emitting element and the light receiving elements, the light emitting element and the light receiving elements being located entirely outside the inner rolling space when viewed in a direction perpendicular to the obverse surface of the mount board;
• and
• a rolling member movably accommodated in the inner rolling space to take any one of a complete light shielding position, a partial light shielding position and a light unshielding position, the complete light shielding position being a position at which the rolling member blocks light emitted from the light emitting element so that the light does not reach neither of the paired light receiving elements, the partial light shielding position being a position at which the rolling member blocks the light emitted from the light emitting element so that the light reaches only one of the paired light receiving elements, the light unshielding position being a position at which the rolling member fails to block the light emitted from the light emitting element so that the light reaches both of the paired light receiving elements;
• wherein the rolling member overlaps the light emitting element and the light receiving elements when viewed in a direction parallel to the obverse surface of the mount board.