Lighting method and apparatus for high-pressure discharge lamp, and high-pressure discharge lamp apparatus
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMasahiro Yamamoto, Shunsuke Ono, Minoru Ozasa
Life of this patent
Estimating the term…
Abstract
Disclosed are a lighting method for a high-pressure discharge lamp, a lighting apparatus for a high-pressure discharge lamp, and a high-pressure discharge lamp apparatus each suppresses abnormal blackening of a discharge tube that may occur at an initial stage of operation from a discharge start. According to the lighting method of the present invention, the lamp current is reduced upon detection, by an abnormal discharge detector 5021, of an abnormal discharge that is produced between a tip of one electrode and a root of the other electrode.
Claims26
A lighting method for a high-pressure discharge lamp that is composed of a discharge tube, the discharge tube being filled with mercury, a rare gas and a halogen material, and having a pair of electrodes provided therein, the lighting method comprising:
- a discharge shift detecting step of detecting that a discharge across the pair of electrodes has shifted to an arc discharge after a discharge starts and before the mercury fully evaporates;
- a voltage rise detecting step of detecting that a lamp voltage has risen to exceed a predetermined level after a shift to an arc discharge is detected and before the mercury fully evaporates;
- and
- a current reducing step of reducing a lamp current when the lamp voltage is detected in the voltage rise detecting step to exceed the predetermined level.
A lighting method for a high-pressure discharge lamp that is composed of a discharge tube, the discharge tube being filled with mercury, a rare gas and a halogen material, and having a pair of electrodes provided therein, the lighting method comprising:
- a time-measuring step of measuring a lapse of a first predetermined time period in a transition state, the transition state beginning at a discharge start and ending at full evaporation of the mercury;
- a voltage rise detecting step of detecting, during the first predetermined time period, that a lamp voltage has risen to exceed a predetermined level after a lapse of a second predetermined time period that is shorter than the first predetermined time period, the predetermined level being higher than a lamp voltage belonging to an arc discharge phase;
- and
- a current reducing step of reducing a lamp current when the lamp voltage is detected in the voltage rise detecting step to exceed the predetermined level.
A lighting apparatus for a high-pressure discharge lamp that is composed of a discharge tube, the discharge tube being filled with mercury, a rare gas and a halogen material, and having a pair of electrodes provided therein, the lighting apparatus comprising:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a shift to an arc discharge is detected and before a predetermined time period is elapsed, the predetermined time period being determined based on a transition state that begins at a discharge start and ends at full evaporation of the mercury, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
Alighting apparatus for a high-pressure discharge lamp that is composed of a discharge tube, the discharge tube being filled with mercury, a rare gas and a halogen material, and having a pair of electrodes provided therein, the lighting apparatus comprising:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a lapse of a first predetermined time period and during a second predetermined time period, the first predetermined time period being shorter than the second predetermined time period, the second predetermined time period being determined based on a transition state that continues until the mercury completely evaporates, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
A high-pressure discharge lamp apparatus comprising:
- a socket for detachable attachment of a high-pressure lamp thereto;
- and
- a lighting circuit for lighting a high-pressure discharge lamp being attached to the socket, the high-pressure discharge lamp being composed of a discharge tube that is filled with mercury and a halogen material, and that is provided with a pair of electrodes,
- wherein the lighting circuit includes:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a lapse of a first predetermined time period and during a second predetermined time period, the first predetermined time period being shorter than the second predetermined time period, the second predetermined time period being determined based on a transition state that continues until the mercury completely evaporates, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
A high-pressure discharge lamp apparatus comprising:
- a socket for detachable attachment of a high-pressure lamp thereto;
- and
- a lighting circuit for lighting a high-pressure discharge lamp being attached to the socket, the high-pressure discharge lamp being composed of a discharge tube that is filled with mercury and a halogen material, and that is provided with a pair of electrodes,
- wherein the lighting circuit includes:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a shift to an arc discharge is detected and before a predetermined time period is elapsed, the predetermined time period being determined based on a transition state that begins at a discharge start and ends at full evaporation of the mercury, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
A high-pressure discharge lamp apparatus comprising:
- a high-pressure discharge lamp composed of a discharge tube, the discharge tube being filled with mercury and a halogen material, and having a pair of electrodes provided therein;
- a lighting circuit for lighting the lamp,
- wherein the lighting circuit includes:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a shift to an arc discharge is detected and before a predetermined time period is elapsed, the predetermined time period being determined based on a transition state that begins at a discharge start and ends at full evaporation of the mercury, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
A high-pressure discharge lamp apparatus comprising:
- a high-pressure discharge lamp composed of a discharge tube, the discharge tube being filled with mercury and a halogen material, and having a pair of electrodes provided therein;
- a lighting circuit for lighting the lamp,
- wherein the lighting circuit includes:
- a lamp voltage detector for detecting a lamp voltage, the lamp voltage being a voltage present across the pair of electrodes;
- a lamp current detector for detecting a current flowing across the pair of electrodes;
- and
- a control circuit for reducing the lamp current when the lamp voltage detector detects that the lamp voltage has risen to exceed a threshold after a lapse of a first predetermined time period and during a second predetermined time period, the first predetermined time period being shorter than the second predetermined time period, the second predetermined time period being determined based on a transition state that continues until the mercury completely evaporates, and the threshold being higher than a lamp voltage belonging to an arc discharge phase.
Dependencies are inferred from the claim text.