Liquid cartridge including fixed plate member having light-shielding region and light-transmissive region

A liquid cartridge attachable to a printer in an attached posture by being moved in a front-rear direction crossing an up-down direction along a gravitational direction, the liquid cartridge comprising:

• a cartridge case defining a liquid storage chamber therein;
• a liquid supply portion protruding frontward from a front surface of the cartridge case and configured to supply liquid stored in the liquid storage chamber to an outside of the liquid storage chamber;
• a circuit board comprising an electrode group comprising at least three electrodes, the at least three electrodes facing upward and being exposed to the outside in the attached posture;
• a residual-amount detecting portion that accommodates an optical access portion accessible by light traveling in a left-right direction crossing the up-down direction and the front-rear direction in the attached posture and configured to change a state of the light according to an amount of the liquid stored in the liquid storage chamber, the optical access portion including a portion positioned above and away from the electrode group by a first distance in the attached posture;
• a base surface, the base surface being positioned above and rearward of the electrode group and facing frontward in the attached posture;
• and
• a plate member, the plate member extending frontward from the base surface in the attached posture, the plate member defining:
• a light-shielding region plate capable of interrupting the light, the light-shielding region plate being positioned rearward of the electrode group and frontward of the residual-amount detecting portion in the attached posture, the light-shielding region plate being positioned above and away from the electrode group by the first distance in the attached posture;
• and
• a light-transmissive region plate having higher light transmittance than the light-shielding region plate, the light-transmissive region plate being positioned rearward of the light-shielding region plate and frontward of the residual-amount detecting portion in the attached posture, the light-transmissive region plate being positioned above and away from the electrode group by the first distance,
• wherein the plate member is immovable relative to the optical access portion.