JP2007103797A - Resistor with lead and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resistor with a lead which is located in a glass tube of a mercury vapor lamp and whose amount of produced gas is sufficiently little, even when its temperature rises at high temperature of approximate 400°C in lighting of the mercury vapor lamp. <P>SOLUTION: A conductive film 13 is formed on a surface of a ceramic substrate 12, and electrode caps 15 are fitted on the both ends of the ceramic substrate, and the resistor 11 with a lead is constructed in a manner such that a lead wire 16 is welded to an electrode cap. The resistor is heated at 350°C to 500°C, and is kept for 40 minutes to 5 hours. The process of heating the resistor 11 with a lead proceeds in inert atmosphere. The conductive film 13 of the resistor 11 with leads is exposed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a leaded resistor in which a conductive film such as a carbon film is formed on the surface of a ceramic substrate, electrode caps are fitted to both ends of the ceramic substrate, and lead wires are welded to the electrode caps, In particular, the present invention relates to a leaded resistor that can be used in a mercury lamp and a method for manufacturing the same.

  Conventionally, a leaded resistor is used in a lighting circuit arranged in a glass tube of a mercury lamp. The glass tube of the mercury lamp reaches a high temperature of about 400 ° C. during lighting, and gas is generated from the leaded resistor by energizing the resistor. When the amount of gas generated is large, the normal lighting state is hindered, such as fogging in the glass tube and adverse effects on the lighting circuit.

By the way, a heat aging step of heating at 100 ° C. to 200 ° C. for 10 hours or more after a step of cutting a part of the carbon film on a leaded carbon film resistor used in an extremely poor environment of high temperature and high humidity. It is known to add (Patent Document 1). According to this patent document, due to the thermal aging, it is possible to suppress a change in resistance value due to weakening of the bonding force of carbon atoms in the cutting part, and to reduce the change in resistance value, and weather resistance reliability is improved. It is described that it improves.
JP-A-2-73601

  However, in the thermal aging described above, the leaded resistor disposed in the glass tube of the mercury lamp reaches a high temperature of about 400 ° C. during the lighting of the mercury lamp, and thus is not necessarily sufficient in terms of suppressing the generated gas.

  The present invention has been made in view of the above-described circumstances, and even when a leaded resistor is disposed in a glass tube of a mercury lamp and the temperature of the mercury lamp becomes high at about 400 ° C., a sufficient amount of gas is generated. An object of the present invention is to provide a small leaded resistor and a method of manufacturing the same.

  In order to solve the above-described problems, a method for manufacturing a resistor with a lead according to the present invention includes forming a conductive film on the surface of a ceramic substrate, fitting electrode caps on both ends of the ceramic substrate, and welding lead wires to the electrode caps. A resistor is constituted, and this resistor is heated in a range of 350 ° C. to 500 ° C. and held for 40 minutes to 5 hours. The step of heating the resistor is preferably performed in an inert atmosphere. In this leaded resistor, the conductive film is preferably exposed.

According to the present invention, sufficient degassing treatment can be performed by heat-treating the leaded resistor at a temperature substantially equal to or higher than the temperature when the mercury lamp is lit. For this reason, in the heat-treated product, the amount of gas generated when kept at a temperature of 400 ° C. for 1 hour is 1 × 10 ⁻³ hPaL or less, and the amount of gas generated can be significantly reduced. As a result, a leaded resistor that can prevent or suppress problems such as fogging in the glass tube of the mercury lamp can be provided, and can contribute to improving the reliability of the mercury lamp.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an embodiment of a resistor with leads according to the present invention.

  In the leaded resistor 11, a conductive film 13 made of a carbon film is formed on the surface of a cylindrical ceramic substrate 12. The conductive film 13 is provided with a kerf 14 for trimming. Electrode caps 15 are fitted on both ends of the ceramic substrate 12 and are electrically connected to the conductive film 13. A lead wire 16 is fixed to the electrode cap 15 by a welded portion 17. Here, the electrode cap 15 is formed by forming a copper plating film and a nickel plating film on the iron surface processed into the shape of the cap. The lead wire 16 is formed by forming a copper plating film on an iron wire.

  As shown in the figure, the leaded resistor 11 does not include an exterior insulating resin layer that covers the conductive film 13 included in a normal resistor, and the conductive film is exposed. This is because the interior of the glass tube of the mercury lamp has a nitrogen atmosphere in which nitrogen gas is sealed, so that the exterior insulating resin layer is essentially unnecessary and gas generation from the exterior insulating resin layer is prevented.

The leaded resistor 11 is formed by forming a conductive film 13 on the surface of the ceramic substrate 12, fitting electrode caps 15 on both ends of the ceramic substrate, welding lead wires 16 to the electrode caps, and forming a resistor. The vessel is formed by heating in a nitrogen gas atmosphere to a range of 350 ° C. to 500 ° C., holding for 40 minutes to 5 hours, and degassing (heat treatment). By this high-temperature degassing treatment, the amount of gas generated when kept at a temperature of 400 ° C. for 1 hour is 1 × 10 ⁻³ hPaL or less, and the amount of gas generated in a high-temperature environment is extremely low. An attached resistor is obtained.

  As an example of the heating temperature of the heat treatment, the pattern shown in FIG. 2 is preferably used. First, it is heated at about 50 ° C. for about 30 minutes, and then heated from 50 ° C. to about 400 ° C. over about 1 hour and 20 minutes, and kept in this state for 1 hour. Then, it waits for temperature to fall to 50 degreeC over about 3 hours, and a heat processing process is completed.

  It is preferable to heat the maximum heating temperature so as to match the conditions actually used (about 400 ° C. with a mercury lamp) or to be harsher conditions. The contained gas cannot be removed at too low a temperature. Further, heating at 500 ° C. or higher is not appropriate considering the influence on the product characteristics. Therefore, it is considered appropriate to remove the contained gas within the range of 350 ° C to 500 ° C.

  Since the gas contained in the resistor cannot be removed sufficiently in a short time, it is preferable to set the time in view of the progress of the gas removal. In this embodiment, the time is about 1 hour. However, if it is about 5 hours at the longest, it is considered that the gas contained therein can be sufficiently removed. Therefore, it is considered appropriate to keep the time in the range of 40 minutes to 5 hours.

  The atmosphere for the heat treatment is an inert atmosphere. This is to prevent oxidation of the lead wire. In this embodiment, the heat treatment is performed in a nitrogen atmosphere. However, if oxidation can be prevented, the heat treatment can be performed in an inert atmosphere other than the nitrogen atmosphere. As another reason, it may be desirable to heat-treat the leaded resistor in the same state as that used in the glass tube of the mercury lamp (used in a nitrogen atmosphere).

  With respect to the resistor subjected to the heat treatment and the resistor not subjected to the heat treatment, an analysis relating to gas generation was performed. As a result, the results shown in Table 1 were obtained. “No heat treatment” in Table 1 means that a resistor in which an electrode cap is fitted on a ceramic substrate on which a carbon film is formed and a lead wire is welded is heated to 400 ° C. in a nitrogen atmosphere without performing the heat treatment. It is the component and the amount of gas generated when kept for 1 hour. “With heat treatment” in Table 1 shows that the resistor in which the electrode cap is fitted and the lead wire is welded to the ceramic substrate on which the carbon film is formed is heat-treated (degassed) according to the pattern shown in FIG. This is the component and amount of gas generated when heated to 400 ° C. in a nitrogen atmosphere and kept in this state for 1 hour.

The amount of gas generated is preferably as close to 0 as possible, but the amount of gas generated when heated to 400 ° C. by heat treatment (degassing treatment) and kept in this state for 1 hour is 1 × 10 ⁻³ hPaL. The goal was to: When the amount of gas generated under the above conditions was confirmed, the above results were obtained.
Not heat-treated = 3.10 × 10 ⁻³ hPaL
Heat treated = 0.66 × 10 ⁻³ hPaL
As described above, it can be seen that the amount of gas generated is reduced to about 1/5 by the heat treatment, and the above target is achieved.

  Table 2 shows the same conditions as the analysis in Table 1 for each part of the resistor, that is, without performing the above heat treatment on each of the ceramic substrate on which the carbon film is formed, the lead wire, and the electrode cap. Then, the components of the gas and the generation amount are examined.

  In addition, although the above analysis heated at 400 degreeC, when heated at about 100 degreeC, generation | occurrence | production of gas was not recognized especially. That is, for example, in the conventional heat treatment method of Patent Document 1, it is understood that the resistor disposed in the glass tube of the mercury lamp is not sufficient as a degassing process.

From each table, the main components of the generated gas were found. Further, it was found from Table 1 that a large amount of CO ₂ was generated. Table 2 shows that gas generation from the electrode cap is large. These gas components are considered to be unavoidable components that are contained in the plating layer by the electrode cap pressing process and the electrode cap and lead wire plating process. Moreover, since the amount of generation for each component is different between Table 1 and Table 2 (for example, H ₂ is reduced in the finished product and CO ₂ is increased in the finished product), lead wire welding, etc. It is considered that the process involving the heating of the gas greatly affects the adhesion of the gas.

Since the generation of gas is recognized in each of the ceramic substrate, lead wire, and electrode cap on which the conductive film is formed, heat treatment is performed individually or collectively at the stage of each component before assembling them into a finished product. It is also effective. Further, from Table 2, since the amount of gas generated from the electrode cap is particularly high as 2.10 × 10 ⁻³ hPaL, it is effective to heat treat only the electrode cap. Furthermore, after heat-treating all or any of the ceramic substrate, lead wire, and electrode cap in advance, each is assembled into a finished product, and the finished product is further heat treated to remove the entire leaded resistor from the finished product. Contributes to reducing gas generation. As the heat treatment conditions described here, the same conditions as those already described can be applied.

Next, a method for manufacturing a resistor with leads according to an embodiment of the present invention will be described with reference to FIG.
(Step 1) Conductive film formation In a vacuum high-temperature furnace containing a ceramic substrate, hydrocarbons are pyrolyzed to deposit a carbon film on the surface of the ceramic substrate.
(Step 2) Assembling An electrode cap is pressed into both ends of the ceramic substrate. Wash the electrode cap.
(Process 3) Selection by resistance value At this stage, the resistance values of individual products vary widely, and therefore, in order to improve the efficiency of the next resistance value adjustment process, products are classified into several types according to the resistance value. .
(Step 4) Resistance Value Adjustment While measuring the resistance value, a spiral cut is made on the surface of the ceramic substrate using a cutter to remove the carbon film, and the resistance value is adjusted. A cut may be made by a laser trimmer.

(Step 5) Cleaning An electrode cap is press-fitted to clean the ceramic substrate whose resistance value has been adjusted, and the residue and the like attached to the resistor surface in the previous step is removed.
(Step 6) Lead wire welding The lead wire is welded to the electrode cap by welding. So-called resistance welding (a large current is applied to the welded joint, heated by resistance heat generated here, and joined by applying pressure) is suitable.
(Step 7) Heat treatment (degassing treatment)
Heat in a nitrogen furnace. The heat treatment is performed in a nitrogen atmosphere and heated in the range of 350 ° C. to 500 ° C. and kept for 40 minutes to 5 hours. By this step, the gas contained in the entire resistor is removed.
(Step 8) Voltage treatment A voltage pulse of about 5 times the rated voltage is applied to stabilize the resistance value.
(Process 9) Inspection, taping, packaging

  Through the above steps, the degassed leaded resistor is completed. As described above, this resistor contributes to the improvement of the reliability of the mercury lamp because it is disposed in the glass tube of the mercury lamp and hardly generates gas even when exposed to a high temperature of about 400 ° C.

  In addition, although the above description demonstrated the example of the carbon film resistor, it can apply similarly also to the resistor with a lead provided with other conductive films, such as a metal film resistor and a metal oxide film resistor. It is.

  Although one embodiment of the present invention has been described so far, it is needless to say that the present invention is not limited to the above-described embodiment, and may be implemented in various forms within the scope of the technical idea.

It is a front view showing one embodiment of a resistor with a lead concerning the present invention, and the left end part of a ceramic base is a sectional view showing a longitudinal section. It is a figure which shows the pattern of the heating temperature of heat processing (degassing process), a horizontal axis shows progress of time, and a vertical axis | shaft shows heating temperature. It is a flowchart which shows one Embodiment of the manufacturing process of the resistor with a lead concerning this invention.

Explanation of symbols

11 Resistor with Lead 12 Ceramic Substrate 13 Conductive Film 14 Groove 15 Electrode Cap 16 Lead Wire 17 Welded Portion

Claims (8)

Form a conductive film on the surface of the ceramic substrate,
Fit electrode caps at both ends of the ceramic substrate,
A resistor is constructed by welding a lead wire to the electrode cap,
A method for manufacturing a leaded resistor, wherein the resistor is heated to a range of 350 ° C. to 500 ° C. and held for 40 minutes to 5 hours.   The method for manufacturing a resistor with leads according to claim 1, wherein the step of heating the resistor is performed in an inert atmosphere.   The method for manufacturing a resistor with leads according to claim 1, wherein the conductive resistor film is exposed in the resistor with leads.   The method for manufacturing a resistor with a lead according to claim 1, wherein the conductive film is a carbon film.   2. The method of manufacturing a resistor with a lead according to claim 1, wherein the electrode cap is formed by forming a copper plating film and a nickel plating film on an iron surface processed into a cap shape. .   2. The method for manufacturing a leaded resistor according to claim 1, wherein the lead wire is formed by forming a copper plating film on a wire made of iron. A leaded resistor comprising: a ceramic substrate having a conductive film formed on a surface thereof; an electrode cap fitted to both ends of the ceramic substrate; and a lead wire welded to both ends of the electrode cap;
A resistor with leads, wherein the amount of gas generated when kept in a state heated to 400 ° C. for 1 hour is 1 × 10 ⁻³ hPaL or less.   The resistor with leads according to claim 7, wherein the conductive film is exposed in the resistor with leads.

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