# US 2014/0191685 A1 · Discharge lamp lighting device, discharge lamp lighting method, and projector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0191685 A1 - Document ID: US20140191685A1 - Status: Published application - Kind: A1 - Application number: 14/134,269 - Filed: 2013-12-19 - Published: 2014-07-10 - Earliest claimed: 2013-01-07 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Yoichi NAKAGOMI; Tetsuo TERASHIMA - Web page: https://patentgrep.com/patent/US20140191685A1 ## CPC - H05B 41/2928: {for protecting the lamp against abnormal operating conditions} - H05B 41/2882: {the control resulting from an action on the static converter} - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A discharge lamp lighting method for controlling lighting of a discharge lamp includes varying an amount of generation (current value) of overshoot and undershoot generated in a waveform of a drive current that is applied when driving the discharge lamp, according to a magnitude of drive power supplied to the discharge lamp and a drive mode. ## Claims ### Claim 1 A discharge lamp lighting device for controlling lighting of a discharge lamp, device comprising: a drive unit that drives the discharge lamp; and a control unit that controls the drive unit; wherein the control unit varies a current value of overshoot and undershoot generated in a waveform of a drive current that is applied when the drive unit drives the discharge lamp, at least according to a magnitude of drive power supplied to the discharge lamp. ### Claim 2 (depends on 1) The discharge lamp lighting device according to claim 1, wherein the control unit causes the current value of overshoot and undershoot to be relatively small when the drive power supplied to the discharge lamp is large, and causes the current value of overshoot and undershoot to be relatively large when the drive power supplied to the discharge lamp is small. ### Claim 3 (depends on 1) The discharge lamp lighting device according to claim 1, wherein the control unit varies the current value of overshoot and undershoot generated in the waveform of the drive current that is applied when the drive unit drives the discharge lamp, according to a drive mode of the discharge lamp. ### Claim 4 (depends on 3) The discharge lamp lighting device according to claim 3, wherein the control unit causes the current value of overshoot and undershoot to be relatively small when an average drive frequency of the discharge lamp is high, and causes the current value of overshoot and undershoot to be relatively large when the average drive frequency of the discharge lamp is low, according to the drive mode of the discharge lamp. ### Claim 5 (depends on 3) The discharge lamp lighting device according to claim 3, wherein the control unit causes the current value of overshoot and undershoot to be relatively large when a range of fluctuation in drive frequency of the discharge lamp is large, according to the drive mode of the discharge lamp. ### Claim 6 (depends on 3) The discharge lamp lighting device according to claim 3, wherein the control unit uses a current value obtained by multiplying the current value of overshoot and undershoot corresponding to the magnitude of the drive power supplied to the discharge lamp by a coefficient corresponding to the drive mode of the discharge lamp. ### Claim 7 (depends on 1) The discharge lamp lighting device according to claim 1, wherein the drive unit has a step-down chopper unit that lowers inputted DC power to a predetermined output voltage and outputs the resulting DC power, and a power conversion unit that converts the DC power supplied from the step-down chopper unit to AC power and outputs the resulting AC power, the step-down chopper unit outputs, based on a control signal from the control unit, DC power that is converted to an output voltage corresponding to a duty ratio of the control signal, and the control unit changes the duty ratio of the control signal during a predetermined period and thus varies the current value of overshoot and undershoot. ### Claim 8 A discharge lamp lighting method for controlling lighting of a discharge lamp, the method comprising: varying a current value of overshoot and undershoot generated in a waveform of a drive current that is applied when driving the discharge lamp, at least according to a magnitude of drive power supplied to the discharge lamp. ### Claim 9 (depends on 8) The discharge lamp lighting method according to claim 8, wherein the current value of overshoot and undershoot is made relatively small when the drive power supplied to the discharge lamp is large, whereas the current value of overshoot and undershoot is made relatively large when the drive power supplied to the discharge lamp is small. ### Claim 10 (depends on 8) The discharge lamp lighting method according to claim 8, wherein according to a drive mode of the discharge lamp, the current value of overshoot and undershoot generated in a waveform of a drive current thereof is varied. ### Claim 11 (depends on 10) The discharge lamp lighting method according to claim 10, wherein according to the drive mode of the discharge lamp, the current value of overshoot and undershoot is made relatively small when an average drive frequency of the discharge lamp is high, whereas the current value of overshoot and undershoot is made relatively large when the average drive frequency of the discharge lamp is low. ### Claim 12 (depends on 10) The discharge lamp lighting method according to claim 10, wherein according to the drive mode of the discharge lamp, the current value of overshoot and undershoot is made relatively large when a range of fluctuation in drive frequency of the discharge lamp is large. ### Claim 13 (depends on 10) The discharge lamp lighting method according to claim 10, wherein a current value obtained by multiplying the current value of overshoot and undershoot corresponding to the magnitude of the drive power supplied to the discharge lamp by a coefficient corresponding to the drive mode of the discharge lamp is used. ### Claim 14 (depends on 1) A projector comprising the discharge lamp lighting device according to claim 1. ### Claim 15 (depends on 2) A projector comprising the discharge lamp lighting device according to claim 2. ### Claim 16 (depends on 3) A projector comprising the discharge lamp lighting device according to claim 3. ### Claim 17 (depends on 4) A projector comprising the discharge lamp lighting device according to claim 4. ### Claim 18 (depends on 5) A projector comprising the discharge lamp lighting device according to claim 5. ### Claim 19 (depends on 6) A projector comprising the discharge lamp lighting device according to claim 6. ### Claim 20 (depends on 7) A projector comprising the discharge lamp lighting device according to claim 7.