| (19) |
 |
|
(11) |
EP 0 254 147 A3 |
| (12) |
EUROPEAN PATENT APPLICATION |
| (88) |
Date of publication A3: |
|
21.03.1990 Bulletin 1990/12 |
| (43) |
Date of publication A2: |
|
27.01.1988 Bulletin 1988/04 |
| (22) |
Date of filing: 09.07.1987 |
|
| (51) |
International Patent Classification (IPC)4: H01J 61/06 |
|
| (84) |
Designated Contracting States: |
|
DE FR GB NL |
| (30) |
Priority: |
15.07.1986 JP 108594/86
15.07.1986 JP 108596/86
|
| (71) |
Applicants: |
|
- TDK Corporation
Chuo-ku,
Tokyo-to 103 (JP)
- MITSUBISHI DENKI KABUSHIKI KAISHA
Tokyo (JP)
|
|
| (72) |
Inventors: |
|
- Iwaya, Shouichi
Chuo-ku Tokyo (JP)
- Masumura, Hitoshi
Chuo-ku Tokyo (JP)
- Hamada, Munemitsu
Chuo-ku Tokyo (JP)
- Adachi, Hiromi
Ohfuna Seisakusho
Mitsubishi Denki
Kamakura-shi
Kanagawa-ken (JP)
|
| (74) |
Representative: Steinmann, Otto C. |
|
Kanzlei Dres. Münich, Neidl-Stippler, Schiller,
Willibaldstr.36/38
D-80689 München
D-80689 München (DE) |
|
| |
|
| (54) |
Hot cathode type discharge lamp apparatus |
(57) Hot cathode type discharge lamp apparatus of the invention is composed of a tube
for discharge lamp, a cathode electrode member in nearly cylindrical form made of
a semiconductor porcelain and arranged within the tube and including a longitudinal
circumferential surface made a discharge surface, and two lead wires connected to
both longitudinal ends of the cathode electrode member and penetrating an end portion
of the tube. In the discharge lamp apparatus, since an electron emission material
is not used in the cathode electrode but the semiconductor porcelain is used, activation
of the electron emission material due to heating is not produced, thereby blackening
phenomenon of the tube wall of the discharge tube can be prevented and the life becomes
long.