JP2623095B2 - Cold cathode discharge lamp device - Google Patents

Description

The present invention relates to a discharge lamp device, and more particularly to a cold cathode discharge lamp device.

(Prior Art) A mercury lamp is known as a cold cathode discharge lamp device. At the same time as the cathode of the mercury lamp is switched on in the cold cathode state, glow discharge starts and, after a few minutes, transitions to arc discharge, whereby the state changes from the cold cathode state to the hot cathode state to emit thermionic emission. Do.

The cathode of such a mercury lamp mixes heat-resistant oxides of alkaline earth metal oxides to create an electron-emitting substance, fills the storage part of the coil-type electrode, and heats it. Made by.

(Problems to be Solved by the Invention) However, when the electrode of a mercury lamp becomes a complete hot cathode as described above and the lamp is stabilized, the electron emitting substance in the storage part of the electrode causes a chemical reaction due to heat. It changes to a substance that evaporates easily and adheres to the tube wall of the arc tube during prolonged operation, causing blackening of the arc tube, deteriorating the luminous flux of the lamp, and shortening the life of the lamp. And other problems arise.

As described above, the prior art has a problem in that the substance on the electrode surface undergoes a chemical change due to heat, causing blackening of the arc tube and shortening of the life.

Further, in this type of lamp, the shorter the time required for the transition from the glow discharge to the arc discharge is better, and it is desired to reduce the time.

The present invention has been made in order to solve the above problems, and its object is to prevent blackening of the tube wall of an arc tube, to prolong the service life, and to shorten the time required for transition from glow discharge to arc discharge. It is an object of the present invention to provide a cold-cathode discharge lamp device which can achieve the following.

[Configuration of the Invention] (Means for Solving the Problems) To achieve the above object, the present invention provides a discharge lamp tube,
The discharge lamp tube comprises an electrode formed of semiconductor porcelain and a cathode having a discharge portion. The discharge portion of the cathode has a higher resistance than the electrode portion. The cold-cathode discharge lamp device is configured such that the resistance of the cold cathode type discharge lamp becomes higher toward the tip of the discharge part.

(Operation) Since the present invention has the above-described configuration, it operates as follows.

That is, since the semiconductor porcelain is used without using the electron emitting material for the cathode, no chemical change occurs due to heating, blackening of the arc tube can be prevented, and the life can be extended. In addition, the resistance of the discharge part of the cathode is made higher than the resistance of the electrode part, and the resistance of the discharge part becomes higher toward the tip of the discharge part. Discharge becomes easy, and the time to shift to arc discharge can be greatly reduced. Furthermore, the arc discharge starting voltage can be reduced.

(Example) Hereinafter, a first example of the present invention will be described in detail with reference to FIG.

The electrode for a discharge lamp shown in FIG. 1 includes a tube 1 for a discharge lamp, a cathode 2 using semiconductor porcelain disposed in the tube 1,
The cathode 2 is connected to a sealing support portion 3 for sealing and supporting the inside of the tubular body 1 and near the end 1a of the tubular body 1 and the cathode 2,
And a lead wire 4 extending to the outside via the sealing support 3.

The cathode 2 has a columnar shape. It comprises an electrode part 2a and a discharge part 2b formed by semiconductor porcelain. This cathode 2
The electrode portion is controlled by controlling the composition of the semiconductor porcelain.
The composition of the discharge portion 2a and the discharge portion 2b is changed so that the resistance increases stepwise or gradually from the base 2d of the electrode portion 2a to the tip of the discharge portion 2b.

The sealing support 3 has a lead wire 4 disposed through the end 1a of the tube 1 and sealed and supported by the end 1a. Connect the end 4a to the electrode
By winding the cathode 2 around the outer periphery of the base 2d of the base 2a, the cathode 2 is supported in the tube 1 so as to be vertically arranged with the end 1a,
The other end 4b of the lead wire 4 projects outward from the end 1a of the tube 1.

Here, the semiconductor porcelain as the material of the cathode 2 will be described in detail.

As this semiconductor porcelain, for example, a valence compensation type semiconductor porcelain can be mentioned. A typical example of the valence-compensating semiconductor porcelain is one using barium titanate.

As is well known, valence compensation means adding a metal ion having a valence different from the constituent metal ion of the metal oxide by ± 1 as an impurity and increasing or decreasing the amount of charge caused by the introduction of the impurity. It is to compensate by the valence of the constituent metal ions.

As the semiconductor agent for valence compensation, Y, Dy, Hf, Ce, P
r, Nd, Sm, Gd, Ho, Er, Tb, Sb, Nb, W, Yb, Sc, Ta, etc. can be added, and these can be added in combination. The amount of the additive is 0.01 to 0.8 mol%, especially 0.1 to 0.5 mol%.
l% is desirable.

On the other hand, the material constituting the cathode 2 composed of the semiconductor porcelain of the present embodiment is preferably a titanate-based material, and in addition to the barium titanate, a strontium titanate-based, calcium titanate-based, or lanthanum titanate-based material is used. You may.
Further, a composite of them may be used. Further, the titanic acid of the titanate may be replaced with one or more of zirconic acid, silicic acid and stannic acid.

In addition, a forced reduction semiconductor porcelain may be used as the discharge electrode semiconductor porcelain of the present invention. This can be obtained by a method of reducing the semiconductor porcelain for the cathode electrode as described above, or by a method of reducing the amount without adding a semiconducting agent if sufficient reducing conditions are given. The reduction in this case is performed in a reducing atmosphere such as N ₂ or H ₂ , and preferably
It can be carried out under a temperature condition of 700 ° C. or more, optimally about 1200 to 1450 ° C.

Further, an electrode can be formed by using a combination of a valence compensation type and a forced reduction type. As an embodiment of this combination, (a). By adding a semiconducting agent, a molded body of a valence-compensating semiconductor porcelain is made.

(B). The compact obtained in (a) is directly reduced and fired, or the sintered porcelain fired in the air is further reduced and fired to obtain a semiconductor porcelain using both a valence compensation type and a forced reduction type.

The cathode 2 of this embodiment uses the above-described semiconductor porcelain, and controls the composition of the semiconductor porcelain to form an electrode portion.
The composition of the discharge part 2a and the discharge part 2b is changed so that the resistance increases gradually or gradually from the base 2d of the electrode part 2a to the tip of the discharge part 2b.

By making the resistance of the discharge part 2b of the cathode 2 higher than the resistance of the electrode part 2a and increasing the resistance toward the tip, the discharge part 2b quickly generates heat during glow discharge, facilitating thermionic emission. Thus, the time required for transition to arc discharge is greatly reduced. Further, the arc discharge starting voltage can be reduced.

Next, various modifications of the discharge lamp device will be sequentially described.

 FIG. 2 shows a discharge lamp device according to a second embodiment.

The difference between this embodiment and the first embodiment is that the cathode 2 '
Instead of changing the composition of the semiconductor porcelain that constitutes
Instead, the tip 2c 'of the discharge part 2b' is formed in a conical shape, thereby making the resistance of the discharge part 2b 'higher than the resistance of the electrode 2a', and increasing the resistance toward the tip.
Other points are the same as in the first embodiment.

 FIG. 3 shows a discharge lamp device according to a third embodiment.

This embodiment is a combination of the first embodiment and the second embodiment. The cathode 12 of this embodiment is formed by controlling the composition of the semiconductor porcelain so that the composition of the electrode portion 12a and the discharge portion 12b is controlled. And the resistance is gradually or gradually increased from the base 12d of the electrode portion 12a to the tip of the discharge portion 12b, and the tip 12c of the discharge portion 12b is formed in a conical shape. .

 FIG. 4 shows a discharge lamp device according to a fourth embodiment.

In this embodiment, a tube 21 for a discharge lamp having a narrowed end 21a is used.
A discharge part 22b is arranged in the tube 21, and a cathode 22 using semiconductor porcelain in which a disk-shaped electrode part 22a seals an end 21a of the tube 21, Cathode 22 as shown
An electrode for external connection 26 made of a conductive cap fitted to the protruding portion 22d of the electrode portion 22a, and a lead wire 24 connected to the external connection electrode 26, and the lead wire 24 is connected to a power source (not shown). Thus, current is supplied.

In the cathode 22 of the present embodiment, the composition of the electrode portion 22a and the discharge portion 22b is changed by controlling the composition of the semiconductor porcelain, and the resistance increases from the base 22d of the electrode portion 22a to the tip of the discharge portion 22b. It is formed so as to increase gradually or gradually.

 FIG. 5 shows a discharge lamp device according to a fifth embodiment.

This embodiment differs from the fourth embodiment in that the tip 32c of the discharge portion 32b is formed in a conical shape instead of changing the composition of the semiconductor porcelain constituting the cathode 32. Make the resistance of 32b higher than the resistance of the electrode part 32a,
In addition, the resistance is increased toward the tip, and the other points are the same as in the fourth embodiment.

 FIG. 6 shows a discharge lamp device according to a sixth embodiment.

This embodiment differs from the fifth embodiment in that the overall shape of the cathode discharge portion 42b is formed in a conical shape, whereby the resistance of the discharge portion 42b is higher than the resistance of the electrode portion 42a, and goes to the tip. The resistance is increased in accordance with the above, and the other points remain unchanged.

 FIG. 7 shows a discharge lamp device according to a seventh embodiment.

This embodiment is a combination of the fourth embodiment and the fifth embodiment. The cathode 52 of the present embodiment is formed by controlling the composition of the semiconductor porcelain so that the composition of the electrode portion 52a and the discharge portion 52b is controlled. Is formed such that the resistance gradually or gradually increases from the base 52d of the electrode portion 52a to the tip of the discharge portion 52b, and the tip 52c of the discharge portion 52b is formed in a conical shape. is there.

 FIG. 8 shows a discharge lamp device according to an eighth embodiment.

This embodiment is a combination of the fourth embodiment and the sixth embodiment. The cathode 62 of this embodiment is formed by controlling the composition of the semiconductor porcelain so that the composition of the electrode portion 62a and the discharge portion 62b is controlled. From the base 62d of the electrode portion 62a to the tip 6 of the discharge portion 62b.
The resistance is gradually or gradually increased toward 2c, and the entire shape of the discharge portion 62b is formed in a conical shape.

Here, an example of a method of increasing the resistance of only the discharge portion of the cathode will be described. First, a 0.0001 molar solution of Mn (NO ₃ ) ₂ is prepared. Next, the resistance is increased by immersing the rod-shaped tip portion of the molded body serving as the cathode in the solution. At this time, first soak and dry the second time, soak to the middle part and dry so that the concentration of Mn (NO ₃ ) _{2 in} the part where the solution is soaked is high, Soak and dry. In this case, a discharge portion is obtained in which the resistance at the tip portion is the highest and the resistance gradually decreases stepwise. What is necessary is just to bake what was obtained in this way, and to measure a specific resistance.

Actually, a fluorescent tube according to the present invention was made, and the discharge starting voltage was compared with that of a conventional fluorescent tube. FIG. 10 illustrates three types of compositions of the cathode part (No. 1 to No. 3), and FIG. 11 shows a shape equivalent to the discharge starting voltage when the shape and composition of the cathode of the fluorescent tube according to the present invention are changed. 3 shows the discharge starting voltage of a conventional fluorescent tube (FL15W). The first
The electrode part, intermediate part, and discharge part in FIG.
In the figure, it means an intermediate part of the electrode part and the discharge part, and a tip part thereof. Further, the discharge starting voltage described here is a voltage at the start of discharging when an AC voltage is gradually applied in a cold cathode state without flowing a residual heat current.

In this experiment, the composition of the cathode was changed to eight types (Figs. 1 to 8) while the composition of the cathode was No. 1 in Fig. 10, and the composition was changed to three points (Fig. 1 to Fig. 8). The discharge starting voltage was measured for the fluorescent tubes in which No. 1 to No. 3 in FIG. 10 were changed. Further, for each cathode, the discharge part has a resistivity twice as large as that of the electrode part.

As is apparent from FIG. 11, the cathode of the present invention has a lower discharge starting voltage than the conventional one. Further, among the cathodes according to the present invention, the discharge start voltage is lower in the conical one than in the flat one in the discharge part. Also, the discharge starting voltage tends to be lower when the resistance of the discharge portion is increased due to the manufacturing method than when only the shape is used.

Next, in order to evaluate the life of the cathode according to the present invention, a flicker test was performed on each of the five fluorescent tubes according to the present invention and the conventional fluorescent tube under the test conditions shown in FIG. The results are as shown in FIG. 13, in which the conventional fluorescent tube breaks at an average of 65,100 times and becomes a point, whereas the fluorescent tube according to the present invention does not show any points even after 100,000 tests. Was. It can be seen that even in such a life, the cathode according to the present invention is superior to the conventional cathode.

In this discharge experiment, when a commercially available fluorescent tube was actually used, the discharge starting voltage was low due to the flow of the residual heat current.However, the comparison was made under the same conditions, and the residual heat current was determined in order to clarify the difference in the discharge start voltage. The test was performed without flowing.

According to the above results, it is understood that the cathode according to the present invention is used for a discharge electrode and has a discharge characteristic equal to or higher than that of a conventional discharge electrode in which an electron emitting material is applied to a tungsten filament.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and it goes without saying that the present invention can be appropriately modified and implemented within the scope of the present invention.

[Effects of the Invention] As described above in detail, according to the present invention, since a semiconductor porcelain is used without using a cathode electrode electron emitting material, there is no chemical change due to heating, and blackening of an arc tube is achieved. The phenomenon can be prevented, and the life of the discharge lamp device can be extended.

In addition, the resistance of the discharge part of the cathode is higher than the resistance of the electrode part, and the resistance of the discharge part is higher toward the tip of the discharge part. , And the time to shift to arc discharge can be greatly reduced. Furthermore, the arc discharge starting voltage can be reduced.

Moreover, since semiconductor porcelain is inexpensive, the cost of the apparatus can be reduced. Further, since the shape of the semiconductor porcelain can be arbitrarily formed, it can be formed into a shape according to the intended use and a shape capable of obtaining desired characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view of a principal part showing a first embodiment of the discharge lamp device of the present invention, FIG. 2 is a sectional view of a principal part showing a second embodiment of the discharge lamp device of the present invention, and FIG. FIG. 4 is a sectional view of a principal part showing a third embodiment of the discharge lamp device, FIG. 4 is a sectional view of a principal part showing a fourth embodiment of the discharge lamp device of the present invention, and FIG. FIG. 6 is a cross-sectional view of a main part showing a sixth embodiment of the discharge lamp device of the present invention. FIG. 7 is a cross-sectional view showing a seventh embodiment of the discharge lamp device of the present invention. FIG. 8 is a partial sectional view showing an eighth experimental example of the discharge lamp device of the present invention, FIG. 9 is a partially enlarged sectional view of FIG. 4, and FIGS. FIG. 10 is a view for explaining test results, FIG. 10 shows a composition example of a test sample, FIG. 11 shows a discharge characteristic diagram, FIG. 12 shows a life test condition, and FIG. 13 shows a life characteristic. 1,21… Discharge lamp tube, 2,12,22,32,42,52,62 …… Cathode, 2a, 12a, 22a, 32a, 42a, 52a, 62a …… Electrode part, 2b, 12b, 22b, 32b, 42b, 52b, 62b ... discharge part.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Haruo Taguchi 1-13-1 Nihonbashi, Chuo-ku, Tokyo Inside TDK Corporation (56) References: JP-B 26-3596 (JP, B1) JP-B-6 −103627 (JP, B2)

Claims (9)

(57) [Claims] 1. A discharge lamp tube, and a cathode attached to the discharge lamp tube and having an electrode portion formed by semiconductor porcelain and a discharge portion, wherein the resistance of the discharge portion of the cathode is reduced. A cold-cathode discharge lamp device wherein the resistance of the discharge part is higher than the resistance of the electrode part, and the resistance of the discharge part is higher toward the tip of the discharge part. 2. The cold cathode discharge lamp device according to claim 1, wherein said cathode is formed by changing the composition of a semiconductor porcelain. 3. The cold cathode discharger according to claim 1, wherein said semiconductor porcelain comprises a valence compensation type semiconductor porcelain, a forced reduction type semiconductor porcelain, or a semiconductor porcelain using both of them. Lighting device. 4. The semiconductor device comprises titanium as a main component,
3. The cold-cathode discharge lamp device according to claim 1, comprising one or more of oxides of barium, strontium, calcium, lanthanum, zircon, and tin. 5. The semiconductor porcelain according to claim 1, wherein Y, Dy, Hf, Ce, Pr, Nd, Sm,
Claim 1 wherein one or more of a semiconductor agent for valence compensation of Gd, Ho, Er, Tb, Sb, Nb, W, Yb, Sc, Ta is added.
Item 3. The cold cathode discharge lamp device according to item 2 or 2. 6. The cathode is formed by winding an end inside a tube of a lead wire penetrating an end of the tube and sealing the lead wire around the end around a cathode electrode portion. The cold-cathode discharge lamp device according to claim 1 or 2, wherein the cold-cathode discharge lamp device is used. 7. The cold-cathode discharge lamp device according to claim 1, wherein the discharge section of the cathode has a substantially cylindrical shape and a tip thereof is formed in a conical shape. 8. The cold-cathode discharge lamp device according to claim 1, wherein said discharge section of said cathode is formed in a conical shape as a whole. 9. The electrode portion of the cathode is formed in a disk shape,
3. The cold-cathode discharge lamp device according to claim 1, wherein said electrode portion seals an end of said tube.