Input device for computer

1. An input device for a computer, comprising:

a main body unit having a receiving space provided therein:

a button unit provided to a top of the main body unit so as to be clickable;

an elastic unit configured to restore the button unit to its original state when clicking on the button unit is released; and

a switch unit provided within the receiving space and subjected to an ON operation or an OFF operation depending on whether the button unit is clicked on,

wherein the button unit further moves by a given depth in a state in which the switch unit maintains the ON operation after being subjected to the ON operation,

wherein a manipulation bar for ON/OFF operating the switch unit protrudes downward on an inner circumference surface of the button unit,

wherein the switch unit comprises an optical transmitter configured to generate a light beam and a first optical receiver disposed to face the optical transmitter and configured to receive the light beam generated by the optical transmitter, wherein when the button unit is not clicked on, the first optical receiver maintains an OFF state by receiving the light beam generated by the optical transmitter, and when the button unit is clicked on, a lower end of the manipulation bar blocks the light beam so that the OFF state is charged to an ON state,

wherein the switch unit further comprises a second optical receiver disposed on one side of the optical transmitter and configured to receive a light beam of the optical transmitter which is reflected from a surface of the manipulation bar at a moment when the lower end of the manipulation bar changes the OFF state to the ON state by blocking the light beam between the optical transmitter and the first optical receiver when the button unit is clicked on,

wherein the manipulation bar is formed in a wedge shape having a wide top and narrow bottom, and converts, into a given signal, an amount of reflection of a light beam according to reflection distances of the light beam, differently formed depending on a degree to which the manipulation bar is lowered, through a control unit, and

the given signal is used as analog input means within a computer.

2. The input device of claim 1 , wherein:

the main body unit includes an upper casing and a lower casing separated from and assembled to each other, and

the button unit is formed by cutting a part of the upper casing or a separate button member is coupled to an opening of the upper casing.

3. The input device of claim 1 , wherein the elastic unit uses an elastic restoring force of the button unit formed in a cantilever shape.

4. The input device of claim 1 , wherein analog information through the analog input means is used as a drawing tool comprising a pen, a paint brush or a calligraphy brush capable of expressing different thicknesses on a computer display.

5. The input device of claim 1 , wherein at least one of a plurality of button members constituting the button unit comprises:

a mouse wheel rotatably coupled to the at least one button member; and

an encoder configured to sense the rotation of a wheel member,

wherein the button member equipped with the mouse wheel and the encoder are integrally raised or lowered.

6. An input device for a computer, comprising:

a main body unit having a receiving space provided therein;

a button unit provided at a top of the main body unit so as to be clickable;

an elastic unit configured to restore the button unit to its original state when clicking on the button unit is released; and

a switch unit provided within the receiving space and subjected to an ON operation or an OFF operation depending on whether the button unit is clicked on,

wherein the button unit further moves by a given depth in a state in which the switch unit maintains the ON operation after being subjected to the ON operation,

wherein the button unit is formed in a shape whose one side is a fixed stage and another side is a free stage and the switch unit is disposed between the fixed stage of the button unit and the free stage of the button unit, which is a point clicked on with a finger,

wherein the switch unit is a microswitch equipped with a contact type button which comes into contact with a bottom of the button unit when the button unit is clicked on and is downward pressed,

wherein the button unit comprises:

a first section which is an isolated distance between the fixed stage and the contact type button; and

a second section which is an isolated distance between the contact type button and the free stage, and

wherein the second section is formed to be longer than the first section.

7. The input device of claim 6 , wherein given stiffness is imparted to the button unit by applying different thicknesses to the first section and the second section.

8. The input device of claim 6 , wherein the button unit comprises:

a left button;

a right button disposed on a right side of the left button in parallel thereto; and

a middle wheel button disposed between the left button and the right button in parallel thereto.

9. The input device of claim 8 , wherein the middle wheel button comprises:

a wheel member installed to be rotatable through a rotation shaft within an installation hole formed near the free stage and having a plurality of optical slits radially formed around the rotation shaft and penetrating the wheel member;

an optical transmitter installed at a bottom of the middle wheel button, disposed on one side of the wheel member so as to be isolated from the wheel member, and configured to generate a light beam; and

an optical receiver installed at the bottom of the middle wheel button, disposed on another side of the wheel member so as to face the optical transmitter, and configured to receive a light beam passing through the optical slits after being generated by the optical transmitter.

10. The input device of claim 8 , wherein the first section of the middle wheel button has a thickness greater than those of the left button and the right button in order to have stiffness greater than those of the left button and the right button.