Image forming apparatus and image forming method

Claim 2

An image forming apparatus comprising: a plurality of electron-emitting devices arranged in a matrix and including a plurality of first and second wirings; a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices; a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to said first wirings other than the selected first wirings; and a second driving circuit for applying a driving potential corresponding to an image signal to the plurality of second wirings, wherein said first and second driving circuits drive said plurality of electron-emitting devices in accordance with the following condition, Vx<Vy ′ and Vy′>Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 3

The apparatus according to claim 1 , further comprising an offset potential generator arranged to generate the potential Vy′ by adding an offset potential Vb to the driving potential.

Claim 4

The apparatus according to claim 1 , further comprising a reference potential generator arranged to generate a reference voltage for adjusting the potential Vx.

Claim 5

The apparatus according to claim 2 , wherein said light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and offset potentials for each color can be adjusted independently.

Claim 6

The apparatus according to claim 3 , wherein said light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and reference voltages for each color can be adjusted independently.

Claim 7

An image forming apparatus comprising: a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings; a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices; a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to first wirings other than said selected first wirings; a second driving circuit for applying a driving potential corresponding to an image signal to said plurality of second wirings; an offset voltage generating unit for generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset voltage generating unit generates the potential Vy′ in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 8

An image forming apparatus comprising: a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings; a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices; a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to first wirings other than said selected first wirings; a second driving circuit for applying a driving potential corresponding to an image signal to said plurality of second wirings; an offset voltage generating unit for generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset voltage generating unit generates the potential Vy′ in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 9

A driving circuit of an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices, said circuit comprising: a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to said first wirings other than the selected first wirings; and a second driving circuit for applying a driving potential corresponding to an image signal to the plurality of second wirings, wherein said first and second driving circuits drives the plurality of electron-emitting devices in accordance with the following condition, Vx<Vy ′ and Vy′>Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 10

A driving circuit of an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices, said circuit comprising: a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to said first wirings other than the selected first wirings; and a second driving circuit for applying a driving potential corresponding to an image signal to the plurality of second wirings, wherein said first and second driving circuits drives the plurality of electron-emitting devices in accordance with the following condition, Vx<Vy ′ and Vy′>Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 11

The apparatus according to claim 7 , further comprising an offset potential generator arranged to generate the potential Vy′ by adding an offset potential Vb to the driving potential.

Claim 12

The apparatus according to claim 7 , further comprising a reference potential generator arranged to generate a reference voltage for adjusting the potential Vx.

Claim 13

The apparatus according to claim 8 , wherein said light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and the offset potentials for each color can be adjusted independently.

Claim 14

The apparatus according to claim 9 , wherein said light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and the reference voltages for each color can be adjusted independently.

Claim 15

A driving circuit of an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices, said circuit comprising: a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to the first wirings other than the selected first wirings; and a second driving circuit for applying a driving potential corresponding to an image signal to the plurality of second wirings; an offset voltage generating unit for generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset voltage generating unit generates the potential Vy′ in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 16

A driving circuit of an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by said electron-emitting devices, said circuit comprising: a first driving circuit for applying a scanning selection potential to selected first wirings and for applying a non-selection potential to the first wirings other than the selected first wirings; and a second driving circuit for applying a driving potential corresponding to an image signal to the plurality of second wirings; an offset voltage generating unit for generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset voltage generating unit generates the potential Vy′ in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 17

A driving method for driving an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by the electron-emitting devices, said method comprising the steps of: applying a scanning selection potential to selected first wirings and applying a non-selection potential to first wirings other than the selected first wirings; and applying a driving potential corresponding to an image signal to the plurality of second wirings, wherein said applying steps drive the plurality of electron-emitting devices in accordance with the following condition, Vx<Vy ′ and Vy′>Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 18

A driving method for driving an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by the electron-emitting devices, said method comprising the steps of: applying a scanning selection potential to selected first wirings and applying a non-selection potential to first wirings other than the selected first wirings; and applying a driving potential corresponding to an image signal to the plurality of second wirings, wherein said applying steps drive the plurality of electron-emitting devices in accordance with the following condition, Vx<Vy ′ and Vy′>Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 19

The method of claim 13 , further comprising an offset potential generating step of generating the potential Vy′ by adding an offset potential Vb to the driving potential.

Claim 20

The method according to claim 13 , further comprising a reference potential generating step of generating a reference voltage for adjusting the potential Vx.

Claim 21

The method according to claim 14 , wherein the light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and the offset potentials for each color can be adjusted independently.

Claim 22

The method according to claim 15 , wherein the light-emitting substance includes three types of light-emitting substances for emitting light of three colors, and the reference voltages for each color can be adjusted independently.

Claim 23

A driving method for driving an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by the electron-emitting devices, said method comprising the steps of: applying a scanning selection potential to a plurality of first wirings and applying a non-selection potential to the first wirings other than the selected first wirings; applying a driving potential corresponding to an image signal to the plurality of second wirings; and generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset potential Vy′ is generated in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.

Claim 24

A driving method for driving an image forming apparatus having a plurality of electron-emitting devices arranged in a matrix using a plurality of first and second wirings and a light-emitting substance for emitting light by irradiation of electrons emitted by the electron-emitting devices, said method comprising the steps of: applying a scanning selection potential to a plurality of first wirings and applying a non-selection potential to the first wirings other than the selected first wirings; applying a driving potential corresponding to an image signal to the plurality of second wirings; and generating a potential Vy′ by adding an offset potential Vb to said driving potential, wherein said offset potential Vy′ is generated in accordance with the following condition, Vx<Vy ′ and Vy′≈Vth, where Vth represents a threshold voltage to be applied to an electron-emitting device for emitting electrons needed for the light-emitting substance to emit light, Vx represents a potential difference between a maximum potential corresponding to a maximum luminance level and a minimum potential corresponding to a minimum luminance level among driving potentials selectable based on luminance of the image signal, and Vy′ represents a potential difference between the minimum potential and the scanning selection potential.