Computer indexing device

An indexing device, comprising:

• a first sensing unit, generating a first move detection signal;
• a second sensing unit, generating a second move detection signal;
• a control unit, coupled with the first sensing unit and the second sensing unit;
• and
• a positioning member;
• wherein the control unit operates to generate a cursor control signal in response to a variance of the first move detection signal and/or the second move detection signal;
• wherein one of the first sensing unit and second sensing unit comprises:
• a sliding member, disposed on a casing of the device,
• an opening member formed on the sliding member, and
• a sensing module, slidably disposed on the sliding member;
• wherein the sensing module outputs a light signal through the opening member for detecting a movement of the casing;
• wherein the sensing module comprises:
• a substrate;
• a lens set, disposed on the substrate, directed toward the opening member;
• a sensor chip, disposed on the substrate, adjacent to the lens set;
• and
• a sliding board, connected with the substrate, slidably connected with the sliding member;
• wherein the sensor chip outputs the light signal through the lens set to the opening member;
• wherein the sliding board comprises:
• a containing member for containing the substrate, the lens set, and the sensor chip, adjacent to the positioning member;
• and
• a shelter member, extending to the outside of the containing member and contacted with the casing, for sheltering the opening member between the containing member and the casing;
• wherein the containing member has a perforating member directed toward the opening member and is formed corresponding to the lens set;
• and
• wherein the positioning member is disposed at one side of the sliding member for positioning the sensing module on the sliding member.