# US 6,294,876 B1 · Electron-beam apparatus and image forming apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,876 B1 - Document ID: US6294876B1 - Status: Granted - Kind: B1 - Application number: 09/512,362 - Filed: 2000-02-24 - Granted: 2001-09-25 - Earliest claimed: 1999-02-24 - Assignees: Canon Kabushiki Kaisha - Inventors: Muneki Ando; Kenji Shino - Web page: https://patentgrep.com/patent/US6294876B1 ## CPC - G09G 3/22: using controlled light sources - G09G 3/2014: {by modulation of the duration of a single pulse during which the logic level remains constant} - G09G 2310/0275: Details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related to handling digital grey scale data or to communication of data to the pixels by means of a current - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract This invention stabilizes the electron emission amount and displays an image on the entire display screen with a luminance faithful to an original image signal, while preventing characteristic degradation and destruction of an electron source. In an apparatus according to this invention, a V/I converter (108) includes n independent constant current sources in correspondence with n column-direction wirings. Each constant current source (108) is made up of an operational amplifier, transistor, and resistor. A voltage limiting circuit (209) uses a diode (D). A limit value setting circuit (110) is constituted by, e.g., a D/A converter and buffer amplifier or a potentiometer and buffer amplifier connected to a power supply. A spike current absorbing means (211) uses a capacitor (C). As the capacitance increases, the wiring voltage rise (ΔVs) decreases. Thus, the necessary capacitance of the capacitor (C) of the spike current absorbing means (211) is desirably 0.1 μF or more. ## Claims ### Claim 1 An electron-beam apparatus comprising: an airtight container having an electron-emitting device, a wiring connected to the electron-emitting device, and an electrode which receives a potential for accelerating an electron emitted by the electron-emitting device; and a current absorbing unit which can be electrically connected to the wiring, said current absorbing unit absorbing a current generated by discharge in said airtight container. ### Claim 2 (depends on 1) The apparatus according to claim 1, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said current absorbing unit includes current absorbing units arranged in correspondence with the respective wirings. ### Claim 3 (depends on 1) The apparatus according to claim 1, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said current absorbing unit corresponds to the plurality of wirings. ### Claim 4 (depends on 1) The apparatus according to claim 1, wherein the wiring is a first wiring, the apparatus further comprises a second wiring, and the electron-emitting device is connected to the first and second wirings. ### Claim 5 (depends on 1) The apparatus according to claim 1, wherein the electron-emitting device is a surface-conduction emission type electron-emitting device. ### Claim 6 (depends on 1) The apparatus according to claim 1, wherein the electron-emitting device is a field emission type electron-emitting device. ### Claim 7 (depends on 1) The apparatus according to claim 1, wherein the electron-emitting device is a metal/insulator/metal type (MIM type) electron-emitting device. ### Claim 8 (depends on 1) An image forming apparatus comprising: the electron-beam apparatus defined in claim 1; and a fluorescent substance for emitting light upon irradiation of an electron emitted by the electron-emitting device. ### Claim 9 (depends on 1) The apparatus according to claim 1, wherein the discharge causes the generation of a spike-shaped voltage on the wiring. ### Claim 10 (depends on 1) The apparatus according to claim 1, wherein the discharge causes the generation of a spike voltage on the wiring. ### Claim 11 An electron-beam apparatus comprising: an airtight container having an electron-emitting device, a wiring connected to the electron-emitting device, and an electrode which receives a potential for accelerating an electron emitted by the electron-emitting device; a bypass which can be electrically connected to the wiring; and a switch for electrically connecting the wiring and said bypass when discharge occurs in said airtight container. ### Claim 12 (depends on 11) The apparatus according to claim 11, wherein said switch operates depending on a potential difference between a wiring-side potential and a bypass-side potential. ### Claim 13 (depends on 12) The apparatus according to claim 12, wherein said switch receives a predetermined potential as the bypass-side potential. ### Claim 14 (depends on 12) The apparatus according to claim 12, wherein said switch is a diode. ### Claim 15 (depends on 11) The apparatus according to claim 11, wherein said bypass comprises absorbing means for absorbing a current generated by discharge. ### Claim 16 (depends on 11) The apparatus according to claim 11, wherein said bypass comprises a capacitor. ### Claim 17 (depends on 11) The apparatus according to claim 11, further comprising a driver for supplying a signal for driving the electron-emitting device to the wiring. ### Claim 18 (depends on 17) The apparatus according to claim 17, wherein said driver is a circuit for generating a current having a predetermined current value. ### Claim 19 (depends on 18) The apparatus according to claim 18, wherein said switch serves as a switch for electrically connecting said bypass and said driver when a potential at an output terminal of said driver for supplying a current to the wiring falls outside a predetermined range. ### Claim 20 (depends on 11) The apparatus according to claim 11, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said bypass includes bypasses arranged in correspondence with the respective wirings. ### Claim 21 (depends on 11) The apparatus according to claim 11, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said bypass corresponds to the plurality of wirings. ### Claim 22 An electron-beam apparatus comprising: an airtight container having an electron-emitting device, a wiring connected to the electron-emitting device, and an electrode which receives a potential for accelerating an electron emitted by the electron-emitting device; a capacitor which can be electrically connected to the wiring; and a switch which is interposed between the wiring and said capacitor and electrically connects the wiring and said capacitor depending on a wiring-side potential, wherein said switch operates depending on a potential difference between the wiring-side potential and a capacitor-side potential. ### Claim 23 (depends on 22) The apparatus according to claim 22, wherein said switch is a diode. ### Claim 24 (depends on 22) The apparatus according to claim 22, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor includes capacitors arranged in correspondence with the respective wirings. ### Claim 25 (depends on 22) The apparatus according to claim 22, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor corresponds to the plurality of wirings. ### Claim 26 (depends on 22) The apparatus according to claim 22, further comprising a driver for supplying to the wiring a signal for driving the electron-emitting device. ### Claim 27 (depends on 26) The apparatus according to claim 26, wherein said driver is a circuit for generating a current having a predetermined current value. ### Claim 28 (depends on 22) The apparatus according to claim 22, wherein said switch receives a predetermined potential as the capacitor-side potential. ### Claim 29 (depends on 28) The apparatus according to claim 28, wherein said switch is a diode. ### Claim 30 (depends on 28) The apparatus according to claim 28, further comprising a driver for supplying to the wiring a signal for driving the electron-emitting device. ### Claim 31 (depends on 30) The apparatus according to claim 30, wherein said driver is a circuit for generating a current having a predetermined current value. ### Claim 32 (depends on 28) The apparatus according to claim 28, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor includes capacitors arranged in correspondence with the respective wirings. ### Claim 33 (depends on 28) The apparatus according to claim 28, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor corresponds to the plurality of wirings. ### Claim 34 An electron-beam apparatus comprising: an airtight container having an electron-emitting device, a wiring connected to the electron-emitting device, and an electrode which receives a potential for accelerating an electron emitted by the electron-emitting device; and a capacitor which can be electrically connected to the wiring, wherein said capacitor has an electrostatic capacitance of not less than 0.1 μF. ### Claim 35 (depends on 34) The apparatus according to claim 34, further comprising a switch which is interposed between the wiring and said capacitor and electrically connects the wiring and said capacitor depending on a wiring-side potential, wherein said switch is a diode. ### Claim 36 (depends on 34) The apparatus according to claim 34, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor includes capacitors arranged in correspondence with the respective wirings. ### Claim 37 (depends on 34) The apparatus according to claim 34, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor corresponds to the plurality of wirings. ### Claim 38 (depends on 34) The apparatus according to claim 34, further comprising a driver for supplying to the wiring a signal for driving the electron-emitting device. ### Claim 39 (depends on 38) The apparatus according to claim 38, wherein said driver is a circuit for generating a current having a predetermined current value. ### Claim 40 An electron-beam apparatus comprising: an airtight container having an electron-emitting device, a wiring connected to the electron-emitting device, and an electrode which receives a potential for accelerating an electron emitted by the electron-emitting device; a capacitor which can be electrically connected to the wiring; a switch, said switch serving as a switch for electrically connecting the wiring and said capacitor; and another switch for electrically connecting a bypass and a driver when a potential at an output terminal of the driver for supplying a current to the wiring falls outside a predetermined range. ### Claim 41 (depends on 40) The apparatus according to claim 40, wherein at least one of said switches is a diode. ### Claim 42 (depends on 40) The apparatus according to claim 40, further comprising a driver for supplying to the wiring a signal for driving the electron-emitting device. ### Claim 43 (depends on 42) The apparatus according to claim 42, wherein said driver is a circuit for generating a current having a predetermined current value. ### Claim 44 (depends on 40) The apparatus according to claim 40, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor includes capacitors arranged in correspondence with the respective wirings. ### Claim 45 (depends on 40) The apparatus according to claim 40, wherein the electron-emitting device includes a plurality of electron-emitting devices, the wiring includes wirings for the respective electron-emitting devices, and said capacitor corresponds to the plurality of wirings. ### Claim 46 An electron-beam apparatus comprising: an airtight container having a plurality of electron-emitting devices, a plurality of wirings which are connected to the electron-emitting devices and arranged in correspondence with the respective electron-emitting devices, and an electrode which receives a potential for accelerating electrons emitted by the electron-emitting devices; one bypass which can be electrically connected to the plurality of wirings; and switches for electrically connecting the wirings and said bypass, wherein at least one of said switches operates depending on a potential difference between the wiring-side potential and a bypass-side potential, and receives a predetermined potential as the bypass-side potential. ### Claim 47 (depends on 46) The apparatus according to claim 46, wherein said switches are arranged for the respective wirings.