JP4028520B2 - Discharge lamp and manufacturing method thereof - Google Patents

Description

  The present invention relates to a discharge lamp using diamond as an electron-emitting material that emits electrons, and a method for manufacturing the same, and particularly to a discharge lamp suitable for use in backlights for various illuminations and liquid crystal devices, and a method for manufacturing the same. It is about.

  Conventionally, a hot cathode using thermoelectrons emitted when a substance is heated to a high temperature is used as an electron source of a vacuum tube operating in a vacuum such as an X-ray tube or a high-frequency electron tube. Thus, it is widely used as an electron source of a discharge tube operating in a gas. On the other hand, cold cathodes are used for cold cathode discharge lamps and the like, and consume more power than discharge lamps using hot cathodes, but are used for backlights of liquid crystal televisions because of their long life. When the cathode is used as these electron sources, the voltage drop around the electrodes is large. Therefore, it is desired to reduce the voltage drop at the electrodes in the cold cathode discharge lamp. In the case of using a secondary electron as an electron, an alkali metal is known as an electrode material with good emission efficiency. However, the alkali metal has a problem that the sputtering resistance is low and the melting point is low. For this reason, nickel (Ni) and molybdenum (Mo), which are refractory metals, are generally used as electrode materials. In this case, the cathode loss can be reduced by applying BaO or the like to the cathode, but a short life is a serious problem due to the consumption due to sputtering.

  On the other hand, diamond, which is a carbon material, has excellent electron emission characteristics and sputtering resistance, and is a promising electrode material for solving the above problems. As a cold cathode discharge lamp using such a diamond as an electrode material, there is a barrier type cold cathode discharge lamp 101 as shown in FIG. 10 (see, for example, Patent Document 1). A barrier cold cathode discharge lamp 101 shown in FIG. 10 includes a hollow body 102, a pair of electrodes 103a and 103b partially inserted into the hollow body 102, and a phosphor film provided on the inner surface of the hollow body 102. 106. The electrode 103a has a conductor 104a and a diamond film 105a covering the conductor 104a. Similarly, the electrode 103b has a conductor 104b and a diamond 105b covering the conductor 104b. The hollow body 102 is filled with a rare gas. Thus, by using diamond as an electrode material, high luminous efficiency can be obtained and consumption by sputtering can be suppressed to realize a long-life cold cathode.

JP 2003-132850 A

  However, since the surface of the polycrystalline diamond is usually very uneven, there is a problem that a gap is formed between the polycrystalline diamond and the glass tube when the electrode and the glass tube are joined. In addition, there is a problem that the wettability between the polycrystalline diamond and the glass material is poor, and it is difficult to reliably join without any gap. Therefore, when diamond is used as the electrode material, it is difficult to maintain the hermeticity in the discharge lamp, and a cold cathode discharge lamp equipped with an electrode using polycrystalline diamond as an electron-emitting substance is surely produced. There is a problem that is difficult. Therefore, development of a sealing method capable of realizing high airtightness is desired.

  In addition, although the cold cathode discharge lamp has a higher luminous efficiency as the diameter of the discharge lamp is smaller, there is a problem that heat dissipation of the heat inside the discharge lamp is worsened by making it thinner. At present, a cold cathode discharge lamp with the best heat dissipation efficiency can be produced when the diameter is about 4 mm. However, by efficiently releasing the heat inside the discharge lamp, it is possible to further reduce the diameter of the discharge lamp, and it can be expected that the luminous efficiency is increased. Therefore, there is a demand for a structure that can efficiently release the heat inside the discharge lamp in a cold cathode discharge lamp.

  Also, negative electron affinity (NEA) characteristics known as physical properties of wide baton gap semiconductors are beginning to be reported for diamond. However, when diamond is used as the electrode material for the hot cathode, there is a problem in that the hot cathode discharge lamp has a high driving temperature, so that the diamond is graphitized and the characteristics of NEA cannot be fully utilized. For this reason, a structure capable of efficiently releasing the heat inside the discharge lamp is desired.

  When operating the discharge lamp, a driving voltage is required for both the hot cathode and the cold cathode. Here, the luminance can be increased by increasing the driving voltage, but the temperature inside the discharge lamp increases when the driving voltage is increased. Since the luminous efficiency decreases when the temperature inside the discharge lamp rises, it is desired to develop a structure that efficiently releases the heat inside the discharge lamp in order to control the temperature inside the discharge lamp.

  This invention is made | formed in view of the above, Comprising: It aims at obtaining the discharge lamp which has the high luminous efficiency which used the diamond as an electron emission substance, and its manufacturing method. It is another object of the present invention to provide a high-efficiency discharge lamp having high luminous efficiency and easy temperature management inside the discharge lamp, and a method for manufacturing the same.

In order to solve the above-described problems and achieve the object, a discharge lamp according to the present invention includes an envelope having a light transmission part and containing discharge gas and mercury, and an electron on the surface of the substrate. A diamond layer is formed as an emission material, and a pair of electrodes arranged in a state where a part is accommodated in the envelope at the end of the envelope, a bonding layer provided on the diamond layer of the electrode, A sealing material layer made of borosilicate glass provided on the bonding layer, and a phosphor provided on the inner surface of the envelope, wherein the bonding layer includes boron , which is a constituent element of the sealing material layer. In addition, the envelope and the electrode are bonded via a bonding layer and a sealing material layer. In addition, an envelope having a light transmission part and containing discharge gas and mercury and sealed, and a diamond layer as an electron emission material is formed on the surface of the substrate, and a part of the envelope is formed at the end of the envelope. A pair of electrodes arranged in a state of being accommodated in an envelope, a bonding layer provided on the diamond layer of the electrode, and a glass containing titanium oxide and silicon oxide provided on the bonding layer And a phosphor provided on the inner surface of the envelope, wherein the bonding layer includes titanium which is a constituent element of the sealing material layer, and the envelope and the electrode include It is characterized by being bonded through a bonding layer and a sealing material layer.

A discharge lamp manufacturing method according to the present invention is a discharge lamp manufacturing method in which an electrode is bonded to an end of an envelope having an inner surface provided with a phosphor, and a diamond layer is formed on the surface of a substrate. a step of forming to form the electrode, and forming a step of forming a bonding material layer to the diamond layer, the sealing material layer made of borosilicate glass in the junction material layer, the enclosure and electrostatic and a pole, a step portion of the envelope of the end portion odor Te electrodes are bonded via an outer junction material layer accommodated state in the envelope and sealing material layer, a contact as mixture layer, and forming a layer containing boron as an element of the sealing material layer. A discharge lamp manufacturing method according to the present invention is a discharge lamp manufacturing method in which an electrode is bonded to an end of an envelope having an inner surface provided with a phosphor, and a diamond layer is formed on the surface of a substrate. Forming an electrode, forming a bonding material layer on the diamond layer, and forming a sealing material layer made of glass containing titanium oxide and silicon oxide on the bonding material layer. A step of joining the envelope and the electrode via the bonding material layer and the sealing material layer in a state where a part of the electrode is accommodated in the envelope at the end of the envelope; And a layer containing titanium which is a constituent element of the sealing material layer is formed as the bonding material layer.

  According to the present invention, a discharge lamp excellent in luminous efficiency is realized by providing a diamond layer as an electron emitting material on the electrode surface.

  Further, according to the present invention, the envelope and the electrode are joined through the joining layer and the sealing material layer to seal the discharge lamp. The surface of the diamond layer has many irregularities. For this reason, even if the envelope and the electrode are simply joined, it is difficult to perform a highly airtight seal due to the unevenness of the surface of the diamond layer. However, in the present invention, the bonding layer is formed on the surface of the diamond layer with severe irregularities to improve the flatness of the bonding surface, and the sealing material layer is provided on the bonding layer. In the bonding layer, an element that is a constituent element of the sealing material and easily reacts with carbon is included. For example, when the sealing material layer is made of borosilicate glass, the bonding layer contains boron (B). When the sealing material layer is made of glass containing titanium oxide and silicon oxide, the bonding layer contains titanium (Ti). As a result, by heat treatment when welding the sealing material layer, boron (or titanium) diffuses into diamond to form a compound, and boron (or titanium) diffuses into glass to enable dense bonding. Become. Therefore, according to this invention, sealing with high airtightness is made | formed by joining an envelope and an electrode via a joining layer and a sealing material layer.

  Further, according to the present invention, since the diamond layer on the electrode surface partially extends outside the envelope, the amount of heat that can be released from the inside of the discharge lamp to the outside increases, and the temperature inside the discharge lamp increases. Management becomes easy.

  According to the present invention, the hermeticity of a discharge lamp using a coated electrode having a diamond layer as an electron emitting material, which has been difficult to manufacture, can be kept high, and high luminous efficiency using diamond as an electron emitting material can be maintained. There is an effect that it is possible to obtain the discharge lamp and the manufacturing method thereof. Further, according to the present invention, the diamond layer formed on the electrode can efficiently release the heat inside the discharge lamp, and has high luminous efficiency and easy temperature management inside the discharge lamp. There exists an effect that an electric lamp and its manufacturing method can be obtained.

  Hereinafter, a discharge lamp and a manufacturing method thereof according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following description, In the range which does not deviate from the summary of this invention, it can change suitably. Moreover, in the figure shown below, the scale may differ depending on each member for convenience of explanation.

(Embodiment)
First, the discharge lamp and the manufacturing method thereof according to the present invention will be described in more detail based on specific embodiments.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a cold cathode discharge lamp to which the present invention is applied. A cold cathode discharge lamp 1 shown in FIG. 1 includes an envelope 2, and a pair of electrodes (cold cathodes) 3a and 3b partially inserted into the envelope 2 at the end of the envelope 2, And a phosphor film 6 provided on the inner surface of the envelope 2. Between the envelope 2 and the pair of electrodes (cold cathodes) 3a and 3b, bonding layers 7a and 7b and sealing material layers 8a and 8b are provided from the side of the electrodes (cold cathodes) 3a and 3b. The electrode (cold cathode) 3a has a conductor 4a and a diamond layer 5a which is an electron emitting material covering the conductor 4a. Similarly, the electrode (cold cathode) 3b has a conductor 4b and a diamond layer 5b which is an electron emitting material covering the conductor 4b. Part of the diamond layers 5 a and 5 b covered with the conductors 4 a and 4 b are exposed to the outside of the envelope 2. That is, the diamond layers 5a and 5b are arranged from the inside of the envelope 2 to the outside similarly to the conductors 4a and 4b. The envelope 2 contains a rare gas of several tens of Torr and several mg of mercury as discharge gases.

  Hereinafter, each component of the cold cathode discharge lamp 1 described above will be described. The envelope 2 is made of a transparent glass tube having a light transmission part, and forms an airtight space therein. The envelope 2 is filled with a rare gas such as neon, and the gas pressure in the envelope 2 is normally set to about 4000 Pa to 40000 Pa. The envelope 2 is generally a tubular body or a flat hollow body, but may have other shapes. The envelope 2 does not need to be transparent as a whole as long as it has a light transmission part. Furthermore, the envelope 2 can be composed of a plurality of parts.

  The electrode (cold cathode) 3a has a conductor 4a serving as a base of the electrode, and a diamond layer 5a which is an electron emission material coated on the surface thereof. Similarly, the electrode (cold cathode) 3b has a conductor 4b serving as a base of the electrode, and a diamond layer 5b which is an electron emission material coated on the surface thereof. In FIG. 1, a set of electrodes (cold cathodes) 3a and 3b is shown, but a plurality of sets of electrodes (cold cathodes) 3a and 3b can also be used.

  As a material for the conductors 4a and 4b, a metal material is usually used. Among them, in order to form the diamond layer, it is preferable to use a material such as molybdenum, tungsten, nickel, iron, or copper as the material of the conductors 4a and 4b. By using such a material as the material of the conductors 4a and 4b, a diamond film can be easily formed on the surfaces of the conductors 4a and 4b by a CVD method or the like. Moreover, there is no restriction | limiting in particular in the shape of the conductors 4a and 4b, The shape of the conductors 4a and 4b can be made into various shapes, such as rod shape, plate shape, cyclic | annular form, a spiral shape, or a comb shape, for example. Moreover, the thickness of the diamond layers 5a and 5b is not particularly limited, and can be set to an arbitrary thickness.

  The phosphor film 6 contains a phosphor such as an ultraviolet-excited phosphor generally used in a cold cathode discharge lamp. The phosphor film 6 is generally formed on the inner surface of the envelope 2 as shown in FIG. 1, but may be provided at other positions within the envelope 2.

  The bonding layers 7a and 7b are provided in order to reliably bond the envelope 2 and the electrodes (cold cathodes) 3a and 3b to achieve high airtight sealing. The bonding layers 7a and 7b contain a metal element or a metalloid element that is a constituent element of the sealing material layers 8a and 8b and easily reacts with carbon. The metal element or metalloid element is preferably an element having good wettability with both diamond and glass and having a low coefficient of thermal expansion. Since the metal element or metalloid element contained in the bonding layers 7a and 7b has good wettability with both the diamond and the glass material, the bonding layers 7a and 7b are the sealing material layers made of the diamond layers 5a and 5b and the glass material. It is possible to reliably and very accurately join both of 8a and 8b. That is, the metal element (or metalloid element) diffuses into diamond by heat treatment during the welding of the glass tube as the envelope 2 to form a compound, and the metal element (or metalloid element) diffuses into the glass. By doing so, a precise sealing becomes possible.

  In the present invention, the bonding layers 7a and 7b include a layer containing a metal element or a metalloid element that is a constituent element of the sealing material layers 8a and 8b and easily reacts with carbon, and the metal element or the semimetal described above. The metal element or metalloid in which the metal element or metalloid element is diffused and contained in a high concentration in the compound layer formed by diffusing the metal element in diamond and the sealing material layers 8a and 8b It includes a portion in the vicinity of the layer containing the element. In addition, when a layer containing a metal element or metalloid element that is a constituent element of the sealing material layers 8a and 8b and easily reacts with carbon does not remain as it is, the metal element or metalloid element described above is used. A compound layer formed by diffusing in the diamond, and a portion in the vicinity of the diamond layers 5a and 5b in which the metal element or metalloid element in the sealing material layers 8a and 8b is diffused and contained at a high concentration Are referred to as bonding layers 7a and 7b.

  Diamond also has a very low coefficient of thermal expansion. For this reason, when the thermal expansion coefficient of the metal element or metalloid element contained in the bonding layers 7a and 7b is large, the thermal shrinkage rates after bonding of the bonding layers 7a and 7b and the diamond layers 5a and 5b are greatly different. Therefore, the bonding layers 7a and 7b and the diamond layers 5a and 5b may not be firmly bonded. Therefore, by using a metal element or metalloid element having a thermal expansion coefficient as small as possible as the metal element or metalloid element contained in the bonding layers 7a and 7b and having a coefficient of thermal expansion close to that of diamond, It is possible to reliably bond the bonding layers 7a and 7b and the diamond layers 5a and 5b with minimal influence of the heat shrinkage rate.

  Thus, the cold cathode discharge lamp 1 includes the bonding layers 7a and 7b and the sealing material layers 8a and 8b, and the envelope 2 is interposed through the bonding layers 7a and 7b and the sealing material layers 8a and 8b. And the electrodes (cold cathodes) 3a and 3b (more specifically, the diamond layers 5a and 5b) are joined. Thereby, in this cold cathode discharge lamp 1, the glass tube which is the envelope 2 and the electrodes (cold cathodes) 3a and 3b (more specifically, the diamond layers 5a and 5b) are reliably in a highly airtight state. It is sealed.

  As the metal element or metalloid element contained in the bonding layers 7a and 7b as described above, for example, boron (B), titanium (Ti), or the like is preferable.

Boron (B) easily reacts with diamond to form a compound (B ₄ C). Therefore, when boron (B) is included in the bonding layers 7a and 7b, boron (B) and diamond react to form a compound (B ₄ C) to form the bonding layers 7a and 7b and the diamond layer 5a, 5b is bonded very densely and firmly. Further, when borosilicate glass having a low melting point and capable of being welded by low-temperature heating is used as the sealing material layers 8a and 8b, welding between the glass tube as the envelope 2 and the sealing material layers 8a and 8b is performed. As the temperature rises, boron (B) and borosilicate glass are dissolved in solid, whereby the joining layers 7a and 7b and the sealing material layers 8a and 8b are joined very densely and firmly. As a result, the envelope 2 and the electrodes (cold cathodes) 3a and 3b can be reliably joined without a gap, and a highly airtight vacuum seal can be performed.

  On the other hand, titanium (Ti) tends to make carbon and titanium carbide (TiC). Therefore, when titanium (Ti) is contained in the bonding layers 7a and 7b, titanium (Ti) and diamond react to form a compound (TiC), thereby forming the bonding layers 7a and 7b and the diamond layers 5a and 5b. Are joined very densely and firmly. When glass (TiO—SiO-based glass) containing titanium oxide and silicon oxide having a small coefficient of thermal expansion is used as the sealing material layers 8a and 8b, Titanium (Ti) reacts with glass containing titanium oxide and silicon oxide (TiO—SiO-based glass) due to the temperature rise at the time of welding with the sealing material layers 8a and 8b, and the bonding layers 7a and 7b The sealing material layers 8a and 8b are joined very densely and firmly. As a result, the envelope 2 and the electrodes (cold cathodes) 3a and 3b can be reliably joined without a gap, and a highly airtight vacuum seal can be performed.

  In the present invention, chromium (Cr), vanadium (V), manganese (Mn), cobalt (Co), nickel (Ni), molybdenum (Mo), niobium (Nb), tantalum having good wettability with diamond. (Ta), tungsten (W), platinum (Pt) or the like may be provided as a first layer on the diamond layers 5a and 5b, and a layer containing boron (B), titanium (Ti), or the like may be provided thereon. good. In this case, the same effect as described above can be obtained.

  Further, the thickness of the bonding layers 7a and 7b is not particularly limited, but the thickness is such that at least the surfaces of the diamond layers 5a and 5b are not exposed and the unevenness of the diamond layers 5a and 5b is hidden. Even when the bonding layers 7a and 7b are provided, if the unevenness of the diamond layers 5a and 5b is not hidden by the bonding layers 7a and 7b, the vacuum sealing with high airtightness due to the unevenness of the diamond layers 5a and 5b is performed. There is a possibility that it cannot be stopped. Therefore, by forming the bonding layers 7a and 7b with the thicknesses as described above, the unevenness of the diamond layers 5a and 5b can be embedded with the bonding layers 7a and 7b, and the flatness of the surfaces of the bonding layers 7a and 7b can be improved. it can. This eliminates the influence of the unevenness of the diamond layers 5a and 5b at the time of bonding, and connects the glass tube as the envelope 2 and the diamond layers 5a and 5b as the surface layers of the electrodes (cold cathodes) 3a and 3b to the bonding layer 7a. 7b and the sealing material layers 8a and 8b can be securely bonded to each other to realize a highly airtight vacuum seal.

  The cold cathode discharge lamp 1 according to the present invention configured as described above is provided with diamond layers 5a and 5b as electron emitting materials on the surfaces of the electrodes 3a and 3b, thereby realizing a cold cathode discharge lamp having excellent luminous efficiency. Has been. This is because diamond has high secondary electron emission characteristics. That is, in this cold cathode discharge lamp 1, since the electrode surfaces are the diamond layers 5a and 5b, the rare gas ions generated by the discharge collide with the diamond layers 5a and 5b and are emitted from the diamond layers 5a and 5b. Secondary electrons are significantly increased compared to the case where the electrode surface is made of other electrode materials such as glass. That is, the secondary electron emission efficiency can be significantly increased. In this case, the discharge current increases rapidly immediately after the start of voltage application, and as a result, the light emission efficiency is greatly improved. Diamond is very high in sputter resistance as an electrode material. Thereby, it is possible to extend the life of the cold cathode discharge lamp.

  In this cold cathode discharge lamp 1, the diamond layers 5a and 5b covered with the conductors 4a and 4b are partially exposed to the outside of the envelope 2, and the diamond layers 5a and 5b are formed on the conductors 4a and 4b. Similar to 4b, the envelope 2 is arranged from the inside to the outside. Diamond is a material having excellent thermal conductivity. With such a configuration, it is possible to obtain an effect that the amount of heat that can be released from the inside of the cold cathode discharge lamp 1 to the outside increases. That is, the heat dissipation to the outside of the heat generated inside the envelope 2 is greatly improved. Thereby, temperature management inside the cold cathode discharge lamp 1 becomes easy, and it becomes possible to effectively suppress a decrease in luminous efficiency due to a temperature rise inside the envelope 2. Therefore, in this cold cathode discharge lamp 1, the cold cathode discharge lamp 1 having excellent light emission characteristics is realized. Moreover, in this cold cathode discharge lamp 1, by providing the diamond layers 5a and 5b on the surface of the electrode, the electrode drop voltage is lowered and discharge can be performed at a low voltage.

  In the cold cathode discharge lamp 1, the envelope 2 and the electrodes 3a and 3b are joined via the joining layers 7a and 7b and the sealing material layers 8a and 8b as described above. Vacuum sealing is performed. The surface of the diamond layers 5a and 5b has many irregularities. For this reason, even if the envelope 2 and the electrodes (cold cathodes) 3a and 3b are simply sealed, it is difficult to perform highly airtight vacuum sealing due to the unevenness of the surfaces of the diamond layers 5a and 5b. Therefore, in the cold cathode discharge lamp 1, the envelope 2 and the electrodes (cold cathodes) 3a and 3b are bonded and sealed via the bonding layers 7a and 7b and the sealing material layers 8a and 8b, It is possible to perform highly airtight vacuum sealing. As a result, a cold cathode discharge lamp using a diamond-coated electrode, which has been difficult to manufacture in the past, has been realized.

  Below, the manufacturing method of the cold cathode discharge lamp 1 mentioned above is demonstrated. 2-7 is process drawing explaining the manufacturing method of the cold cathode discharge lamp 1. FIG. FIG. 8 is a flowchart illustrating a method for manufacturing the cold cathode discharge lamp 1. Hereinafter, the manufacturing method of the cold cathode discharge lamp 1 will be described with reference to FIGS.

  First, conductors 4a and 4b made of, for example, Ni as shown in FIG. 2 are prepared, and polycrystalline diamond is coated on the entire surface of the conductors 4a and 4b to form diamond layers 5a and 5b as shown in FIG. (Step S1). Next, as shown in FIG. 4, metal layers are formed as bonding material layers 7a 'and 7b' on the diamond layers 5a and 5b (step S2). Here, the bonding material layers 7 a ′ and 7 b ′ are formed around a portion to be bonded to the envelope 2 in a later process. Further, the metal layers that are the bonding material layers 7a 'and 7b' contain the metal element or the semimetal element described above. By forming the bonding material layers 7a ′ and 7b ′, the flatness of the bonding surface with the sealing material layers 8a and 8b, which will be described later, is improved and the bonding properties with the sealing material layers 8a and 8b are improved, and there is no gap. The electrodes (cold cathodes) 3a and 3b and the envelope 2 can be welded.

  Next, as shown in FIG. 5, sealing glass to be the sealing material layers 8a and 8b is disposed on the bonding material layers 7a 'and 7b' (step S3). On the other hand, a glass tube which is an envelope 2 in which a phosphor material is applied and a phosphor film 6 is provided is prepared, and preheating is performed on the envelope 2 in advance. Then, as shown in FIG. 6, the sealing material layer 8 a provided on the electrode (cold cathode) 3 a is aligned with one end of the envelope 2, and the vicinity of the joint is formed by, for example, an oxyhydrogen burner 9. Heat to a predetermined temperature and weld one side electrode (cold cathode) 3a (step S4). Then, a rare gas such as neon (Ne) and a slight amount of mercury (Hg) are introduced into the envelope 2 to weld the electrode (cold cathode) 3b and the other end of the envelope 2 (step). S4). The electrode (cold cathode) 3b and the other end of the envelope 2 are welded in the same manner as the electrode (cold cathode) 3a and one end of the envelope 2 are welded. By passing through the above process, as shown in FIG. 7, the cold cathode discharge lamp 1 which was vacuum-sealed and the inside of the cold cathode discharge lamp 1 was kept highly airtight can be produced.

  Next, the present invention will be described in more detail based on specific examples.

Example 1
In Example 1, a glass tube is used for the envelope 2, a boron film is formed as the bonding material layers 7 a ′ and 7 b ′, and a layer made of borosilicate glass is formed as the sealing material layers 8 a and 8 b. An example in which a cathode discharge lamp was produced will be described. First, a cold cathode discharge lamp was manufactured according to the method for manufacturing a cold cathode discharge lamp described above. Here, rods made of nickel (Ni) were used for the conductors 4a and 4b constituting the electrodes 3a and 3b. Further, a boron (B) film as a bonding material layer 7a ', 7b' was deposited by an electron beam vapor deposition method to a film thickness of about 1 .mu.m so as to hide the polycrystalline diamond irregularities of the diamond layers 5a, 5b. Then, borosilicate glass is used as the sealing glass to be the sealing material layers 8a and 8b, and the envelope 2 is filled with neon (Ne) of several tens of Torr and several mg of mercury in the envelope 2. Was vacuum sealed to prepare a cold cathode discharge lamp.

  The airtightness of the cold cathode discharge lamp produced as described above was in a sufficiently good state, and no deterioration of the airtightness due to discharge was observed. This can be said to be an effect of the present invention in which the envelope 2 and the electrodes (cold cathodes) 3a and 3b are joined via the metal layers 7a and 7b and the sealing material layers 8a and 8b.

  FIG. 9 shows the relationship between the driving voltage and the luminance of this cold cathode discharge lamp. FIG. 9 also shows the relationship between the driving voltage and the luminance of a conventional cold cathode discharge lamp that does not have a diamond layer on the surface of the electrode. In FIG. 9, the characteristic curve A shows the relationship between the driving voltage and the luminance of the cold cathode discharge lamp according to this example, and the characteristic curve B shows the relationship between the driving voltage and the luminance of the conventional cold cathode discharge lamp. Is shown. As can be seen from FIG. 9, in the conventional cold cathode discharge lamp, the drive voltage region showing the brightness close to the maximum brightness is narrow. This is because the current increases due to the increase in voltage and the temperature in the cold cathode discharge lamp rises too much, and the optimum drive voltage range is narrowed.

  On the other hand, in the cold cathode discharge lamp according to the present embodiment, the driving voltage region showing the luminance close to the maximum luminance is significantly wider than that of the conventional cold cathode discharge lamp. This is because the diamond layers 5a and 5b are formed on the surfaces of the electrodes (cold cathodes) 3a and 3b, and a part of the diamond layers 5a and 5b is exposed to the outside of the envelope 2 to thereby form the inside of the envelope 2. This shows that heat can be efficiently released to the outside, so that the heat design in the envelope 2 is facilitated, and even when a large current is passed, the luminance is hardly reduced.

  Further, when the cold cathode discharge lamp according to this example is driven at a current of 120% of the rated value of the conventional cold cathode discharge lamp, the luminance does not decrease and good luminance is obtained, and the temperature in the envelope 2 is increased. Degradation of the light emission characteristics due to the rise was not observed. It has also been found that the drive voltage also decreases by 10% or more. Therefore, according to the cold cathode discharge lamp according to this example, it can be said that a cold cathode discharge lamp having high luminous efficiency has been realized.

(Example 2)
In Example 2, a glass tube is used for the envelope 2, titanium films are formed as the bonding material layers 7a 'and 7b', and titanium oxide and silicon oxide are included as the sealing material layers 8a and 8b. An example in which a cold cathode discharge lamp was produced by forming a layer made of glass (TiO—SiO-based glass) will be described. First, a cold cathode discharge lamp was manufactured according to the method for manufacturing a cold cathode discharge lamp described in the above-described embodiment. Here, rods made of nickel (Ni) were used for the conductors 4a and 4b constituting the electrodes 3a and 3b. Further, titanium (Ti) films were deposited as the bonding material layers 7a ′ and 7b ′ by an electron beam evaporation method so as to have a thickness of about 2 μm so that the polycrystalline diamond irregularities of the diamond layers 5a and 5b were hidden. Then, as the sealing glass to be the sealing material layers 8a and 8b, glass containing a titanium oxide and a silicon oxide (TiO—SiO-based glass) is used, and neon (several tens of Torr) is contained in the envelope 2. Ne) and several mg of mercury were enclosed, and the inside of the envelope 2 was vacuum-sealed to produce a cold cathode discharge lamp.

  Also in the cold cathode discharge lamp according to Example 2 manufactured in this way, when driven at a current of 120% of the rating of the conventional cold cathode discharge lamp, the luminance is not lowered and good luminance is obtained. The deterioration of the light emission characteristics due to the temperature rise in the envelope 2 was not recognized. It has also been found that the drive voltage also decreases by 10% or more. Therefore, according to the cold cathode discharge lamp according to the present example, it can be said that a cold cathode discharge lamp having high luminous efficiency can be realized as in the cold cathode discharge lamp of Example 1.

  In the above, the case where the present invention is applied to a cold cathode discharge lamp has been described as an example. However, the present invention is not limited to a cold cathode discharge lamp, and the same effects as described above can be obtained when applied to a hot cathode discharge lamp. It is done. Conventionally, in a hot cathode discharge lamp, since there is an optimum value depending on the temperature inside the envelope during driving, the current that can be passed through the hot cathode has been limited. By applying the present invention to a hot cathode discharge lamp, the temperature inside the envelope can be reduced, and the current that can be passed through the hot cathode can be increased to obtain good luminance. Furthermore, in the hot cathode discharge lamp to which the present invention is applied, since the loss at the electrode portion due to the electrode voltage drop can be reduced, a hot cathode discharge lamp having higher luminous efficiency can be realized. In addition, since the heat in the envelope can be efficiently released to the outside, it is possible to easily perform temperature management in the envelope in order to effectively prevent the diamond from being graphitized by heat.

  In the hot cathode discharge lamp to which the present invention is applied, the electrode (hot cathode) may have any shape as long as it can be easily processed as a metal. Since the inner lead portion is used as an electrode (hot cathode) as an electrode (hot cathode), an electrode having a simple structure and an efficient efficiency can be easily supplied.

  As described above, the discharge lamp according to the present invention is useful for a discharge lamp that requires high luminous efficiency, and in particular, a discharge lamp with a small diameter suitable for use in backlights for various illuminations and liquid crystal devices. Is suitable.

It is sectional drawing which shows the structure of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is a flowchart explaining the manufacturing process of the cold cathode discharge lamp to which this invention is applied. It is a characteristic view which shows the relationship between the drive voltage and the brightness | luminance of the cold cathode discharge lamp to which this invention is applied. It is sectional drawing which shows the structure of the conventional cold cathode discharge lamp.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cold cathode discharge lamp 2 Enclosure 3a, 3b Electrode (cold cathode)
4a, 4b Conductor 5a, 5b Diamond layer 6 Phosphor film 7a, 7b Bonding layer 7a ', 7b' Bonding material layer 8a, 8b Sealing material layer 9 Oxyhydrogen burner 101 Conventional cold cathode discharge lamp 102 Hollow body 103a, 103b Electrode 104a, 104b Conductor 105a, 105b Insulating film 106 Phosphor film

Claims (7)

An envelope having a light transmission part and containing discharge gas and mercury and sealed;
A pair of electrodes disposed in a state where a diamond layer is formed as an electron emitting material on the surface of the substrate and a part of the diamond layer is accommodated in the envelope at an end of the envelope;
A bonding layer provided on the diamond layer of the electrode;
A sealing material layer made of borosilicate glass provided on the bonding layer;
A phosphor provided on the inner surface of the envelope;
With
The bonding layer comprises boron which is a constituent element of the sealing material layer;
The discharge lamp characterized in that the envelope and the electrode are joined via the joining layer and the sealing material layer. An envelope having a light transmission part and containing discharge gas and mercury and sealed;
A pair of electrodes disposed in a state where a diamond layer is formed as an electron emitting material on the surface of the substrate and a part of the diamond layer is accommodated in the envelope at an end of the envelope;
A bonding layer provided on the diamond layer of the electrode;
A sealing material layer made of glass containing an oxide of titanium and an oxide of silicon provided on the bonding layer;
A phosphor provided on the inner surface of the envelope;
With
The bonding layer comprises titanium which is a constituent element of the sealing material layer;
The discharge lamp characterized in that the envelope and the electrode are joined via the joining layer and the sealing material layer. The discharge lamp according to claim 1 or 2 , wherein a part of the diamond layer extends to the outside of the envelope. The discharge lamp according to any one of claims 1 to 3 , wherein the discharge gas includes a rare gas. A method of manufacturing a discharge lamp in which an electrode is joined to an end of an envelope provided with a phosphor on the inner surface,
Forming a diamond layer on the surface of the substrate to form an electrode;
Forming a bonding material layer on the diamond layer;
Forming a sealing material layer made of borosilicate glass on the bonding material layer;
The envelope and the electrode are joined via the bonding material layer and the sealing material layer in a state where a part of the electrode is accommodated in the envelope at an end portion of the envelope. And a process of
Including
A method for producing a discharge lamp, comprising forming a layer containing boron as a constituent element of the sealing material layer as the bonding material layer. A method of manufacturing a discharge lamp in which an electrode is joined to an end of an envelope provided with a phosphor on the inner surface,
Forming a diamond layer on the surface of the substrate to form an electrode;
Forming a bonding material layer on the diamond layer;
Forming a sealing material layer made of glass containing an oxide of titanium and an oxide of silicon on the bonding material layer;
The envelope and the electrode are joined via the bonding material layer and the sealing material layer in a state where a part of the electrode is accommodated in the envelope at an end portion of the envelope. And a process of
Including
A method of manufacturing a discharge lamp, comprising forming a layer containing titanium which is a constituent element of the sealing material layer as the bonding material layer. The discharge lamp manufacturing method according to claim 5 or 6 , wherein a part of the diamond layer is extended to the outside of the envelope to join the envelope and the electrode.

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