Device for lighting a high-pressure discharge lamp by supplying alternating current

1. A high-pressure discharge lamp lighting device comprising:

a lighting circuit supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling unit varying a frequency of the alternating current without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp, wherein

the frequency controlling unit performs any one of the following controls (i)-(iv) during a predetermined period without dependency on the operating data;

(i) to vary the frequency in a regular manner, and to repeat the predetermined period consecutively;

(ii) to vary the frequency in a regular manner, and to repeat the predetermined period intermittently;

(iii) to vary the frequency in an irregular manner, and to repeat the predetermined period consecutively; and

(iv) to vary the frequency in an irregular manner, to repeat the predetermined period intermittently.

2. The high-pressure discharge lamp lighting device of claim 1 , wherein the frequency controlling unit varies the frequency continuously during the predetermined period.

3. The high-pressure discharge lamp lighting device of claim 1 , wherein

the frequency controlling unit switches the frequency intermittently among two or more values during the predetermined period.

4. The high-pressure discharge lamp lighting device of claim 1 , wherein

the predetermined period includes one or more variable periods during which the frequency is varied continuously and one or more fixed periods during which the frequency is fixed.

5. The high-pressure discharge lamp lighting device of claim 2 , wherein

the frequency controlling unit alternates a variable period and a fixed period, varying the frequency continuously during the variable period without dependency on the operating data, and fixing the frequency during the fixed period.

6. A high-pressure discharge lamp lighting device comprising:

a lighting circuit supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling unit varying a frequency of the alternating current without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp, wherein

the frequency controlling unit performs one of the following controls (i) and (ii) without dependency on the operating data;

(i) to constantly vary the frequency in a regular manner; and

(ii) to constantly vary the frequency in an irregular manner.

7. A high-pressure discharge lamp lighting device comprising:

a lighting circuit for supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling unit for performing any one of the following controls (i)-(iv) during a predetermined period without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp;

(i) to vary the frequency in a regular manner, and to repeat the predetermined period consecutively;

(ii) to vary the frequency in a regular manner, and to repeat the predetermined period intermittently;

(iii) to vary the frequency in an irregular manner, and to repeat the predetermined period consecutively; and

(iv) to vary the frequency in an irregular manner, to repeat the predetermined period intermittently.

8. The high-pressure discharge lamp lighting device of claim 7 , wherein

the frequency controlling unit varies the frequency continuously during the predetermined period.

9. The high-pressure discharge lamp lighting device of claim 7 , wherein

the frequency controlling unit switches the frequency intermittently among two or more values during the predetermined period.

10. The high-pressure discharge lamp lighting device of claim 7 , wherein

the predetermined period includes one or more variable periods during which the frequency is varied continuously and one or more fixed periods during which the frequency is fixed.

11. A high-pressure lamp lighting method comprising:

a lighting step of supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling step of varying a frequency of the alternating current without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp, wherein

in the frequency controlling step, any one of the following controls (i)-(iv) is performed during a predetermined period without dependency on the operating data;

(i) to vary the frequency in a regular manner, and to repeat the predetermined period consecutively;

(ii) to vary the frequency in a regular manner, and to repeat the predetermined period intermittently;

(iii) to vary the frequency in an irregular manner, and to repeat the predetermined period consecutively; and

(iv) to vary the frequency in an irregular manner, to repeat the predetermined period intermittently.

12. A high pressure discharge lamp lighting method comprising:

a lighting step of supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling step of varying a frequency of the alternating current without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp, wherein

in the frequency controlling step, a variable period and a fixed period are alternated, the frequency being varied continuously during the variable period without dependency on the operating data, and being fixed during the fixed period.

13. A high-pressure discharge lamp lighting method comprising:

a lighting step of supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling step of varying a frequency of the alternating current without dependency on operating data that varies with an elapsed lighting time of the high-pressure discharge lamp, wherein

in the frequency controlling step, one of the following controls (i) and (ii) is performed without dependency on the operating data;

(i) to constantly vary the frequency in a regular manner; and

(ii) to constantly vary the frequency in an irregular manner.

14. A high-pressure discharge lamp lighting method comprising:

a lighting step of supplying an alternating current to a high-pressure discharge lamp to cause lighting, the high-pressure discharge lamp having an arc tube in which a halogen material is enclosed and a pair of electrodes is disposed, and each electrode having a protuberance at a tip thereof; and

a frequency controlling step performs any one of the following controls (i)-(iv) during a predetermined period without dependency on the operating data;

(i) to vary the frequency in a regular manner, and to repeat the predetermined period consecutively;

(ii) to vary the frequency in a regular manner, and to repeat the predetermined period intermittently;

(iii) to vary the frequency in an irregular manner, and to repeat the predetermined period consecutively; and

(iv) to vary the frequency in an irregular manner, to repeat the predetermined period intermittently.