Semiconductor element, electric circuit, display device and light-emitting device

A semiconductor element comprising:

• a gate electrode contacting with an insulating surface;
• a gate film formed on the insulating surface so as to cover the gate electrode;
• and a semiconductor layer contacting with the gate insulating film,
• the semiconductor layer having a channel forming region and at least three impurity regions,
• the gate electrode and the channel forming region sandwiching the gate insulating film therebetween and overlapping each other, and
• said at least three impurity regions contacting with the channel forming region.

An electric circuit for storing electric current data and outputting electric current in accordance with the electric current data, comprising:

• a writing element for selecting whether it inputs a current data signal to the electric circuit or not;
• and a driving element for outputting electric current in accordance with the current data,
• wherein a semiconductor element is used in at least one of the writing element and the driving element, and
• wherein said driving element operates in a saturable region.

A light-emitting device having a pixel provided with a luminous element, wherein the pixel comprises:

• a writing element for selecting input of a video signal in a form of a current value for the pixel;
• a driving element for controlling the amount of electric current flowing to the luminous element;
• and a capacitance element for keeping the gate voltage of the driving element, and
• wherein a semiconductor element is used in at least one of the writing element and the driving element.

A light-emitting device having a pixel provided with a luminous element, wherein the pixel comprises:

• a writing element for selecting input of a video signal in a form of a current value for the pixel;
• a driving element for controlling the amount of electric current flowing to the luminous element;
• and a capacitance element for keeping the gate voltage of the driving element,
• wherein a semiconductor element is used in at least one of the writing element and the driving element, and
• wherein said driving element operates in a saturable region.

A light-emitting device having a pixel provided with a luminous element, wherein the pixel comprises:

• a writing element for selecting input of a video signal in a form of a current value for the pixel;
• and a driving element for controlling the amount of electric current flowing to the luminous element,
• wherein a semiconductor element is used in the driving element, and
• wherein said driving element operates in a saturable region.

A light-emitting device having a pixel provided with a luminous element, wherein the pixel comprises:

• a writing element for selecting input of a video signal in a form of a current value for the pixel;
• a driving element for controlling the amount of electric current flowing to the luminous element;
• a capacitance element for keeping the gate voltage of the driving element;
• and an initializing element for selecting release of electric charge kept in the capacitance element, and
• wherein a semiconductor element is used in the driving element.

A light-emitting device having a pixel provided with a luminous element, wherein the pixel comprises:

• a writing element for selecting input of a video signal in a form of a current value for the pixel;
• a driving element for controlling the amount of electric current flowing to the luminous element;
• a capacitance element for keeping the gate voltage of the driving element;
• and an initializing element for selecting release of electric charge kept in the capacitance element,
• wherein a semiconductor element is used in the driving element, and
• wherein said driving element operates in a saturable region.

A light-emitting device comprising a pixel provided with a luminous element,

• wherein the pixel comprises:
• a writing element;
• a driving element;
• an initializing element;
• and a capacitance element,
• wherein one of the plural impurity regions included in the writing element is connected to a source signal line, one is connected to either a source region or a drain region of the initializing element and one is connected to a impurity region selected from three impurity regions of the driving element,
• wherein one of the source region and the drain region of the initializing element is connected to a power supply line while the other is connected to a impurity region selected from a plurality of impurity regions included in the writing element, and
• wherein one of the three impurity regions included in the driving element is connected to the power supply line, one is connected to a pixel electrode of the luminous element and one is connected to a impurity region selected from the impurity regions of the writing element.

A light-emitting device comprising a pixel provided with a luminous element,

• wherein the pixel comprises:
• a writing element;
• a driving element;
• an initializing element;
• and a capacitance element,
• wherein one of the plural impurity regions included in the writing element is connected to a source signal line, one is connected to either a source region or a drain region of the initializing element and one is connected to a impurity region selected from three impurity regions of the driving element,
• wherein one of the source region and the drain region of the initializing element is connected to a power supply line while the other is connected to a impurity region selected from a plurality of impurity regions included in the writing element, and
• wherein one of the three impurity regions included in the driving element is connected to the power supply line, one is connected to a pixel electrode of the luminous element and one is connected to a impurity region selected from the impurity regions of the writing element, and
• wherein said driving element operates in a saturable region.