JP2008053117A - Fluorescent lamp, light source device, display device, and lighting method of fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve luminous efficiency in a fluorescent lamp. <P>SOLUTION: In the fluorescent lamp 1, the outer diameter of a glass tube 2 is set to 5.0 mm or less, and the adhesion area to which an emissive material is adhered of a core wire of a spiral coil part 4a is set to 1 mm<SP>2</SP>or more and less than 50 mm<SP>2</SP>. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fluorescent lamp, a light source device including the fluorescent lamp, a display device including the light source device, and a fluorescent lamp lighting method.

In a display device called a so-called flat panel display such as a liquid crystal display, an optical element (such as a liquid crystal element) that contributes to light output is not a self-luminous element but a passive type that modulates light applied from the outside. Since it is an element, a light source device for illumination is provided separately from the optical element.
This light source device generally has a direct method, which is advantageous for high brightness, high efficiency, and large size, and an edge light (side light), which is advantageous for miniaturization, thinning, and low power consumption. There are two types of systems.

The direct type has a structure in which a light source device using a plurality of lamps is provided on the back surface (back surface) facing the display surface (front surface). For this reason, the light from the light source device can be used more directly, but on the other hand, it is difficult to reduce the thickness and the power consumption is large.
On the other hand, in the edge light system, for example, an acrylic plate-shaped light guide (light guide) is disposed on the back surface facing the display surface, and a light source device is provided at the end of the light guide (on the side of the display). Have a structured. Since light is diffused in the light guide unit, the thickness and power consumption can be reduced, but the weight of the light guide unit and the like increases as the screen size increases. In addition, this edge light system further includes a backlight type in which the position of the light source device is on the back side, and reflected light generated by reflection or semi-transmission (hybrid of reflection and transmission) in the optical element on the surface side of the light source device. It is classified into the front light type that uses the.

Incidentally, in recent years, not only small display devices such as mobile phones but also large display devices tend to be thinner. Since the cold cathode fluorescent lamp has a low luminous efficiency, when incorporated in a large display device, not only an increase in power consumption becomes a problem, but also a high lighting voltage makes it difficult to increase the tube length.
For this reason, hot cathode fluorescent lamps are attracting attention because of their high luminous efficiency (low power consumption) and longer tube lengths compared to cold cathode types.

However, it has been pointed out that a hot cathode fluorescent lamp has a short life. For this reason, various proposals have been made for the purpose of extending the life.
For example, by increasing the inner diameter of the fluorescent tube (glass tube of the fluorescent lamp) (for example, 9.6 mm) and increasing the surface area of the electron emitting material (for example, 50 mm ^{2 to} 200 mm ² ), the electrode can be lit without preheating. There has been proposed a technique that enables this and extends the life (see, for example, Patent Document 1). In addition, for example, an alkaline earth metal tantalate is used as the electron emission material, and the lifetime is extended by a lighting method in which a preheating current is supplied to the filament so that the temperature of the cathode bright spot (hot spot) is 1100 ° C. to 1300 ° C. A technique for achieving this has also been proposed (see, for example, Patent Document 2).

However, although these methods are possible with relatively large fluorescent lamps, they may not be suitable for smaller fluorescent tubes, for example when the outer diameter of the glass tube is 5.0 mm or less. is there.
For example, based on the technique described in Patent Document 1, when the outer diameter of the fluorescent tube is 5.0 mm or less and the surface area of the electron emitting material is to be 50 mm ² or more, the length of the electrode (the tube of the glass tube) The longitudinal dimension along the axis) must be increased. Since the electrode itself is a so-called ineffective light emitting portion that does not emit light, for example, if the electrode becomes larger than the width of a frame (narrow frame) around the display surface, the area of the display surface is substantially reduced. Further, for example, in the case of the method described in Patent Document 2, the shape of the electrode is not a tube axis (not the tube axis), but is a uniaxial coil shape with the tube diameter as the longitudinal direction. It is considered that the outer diameter and the lamp current must be 15 mm or more and 200 mA or more, respectively.

On the other hand, there has also been proposed a method that considers lighting with a relatively low lamp current (for example, 100 mA or less) in a smaller fluorescent tube (for example, an outer diameter of 5.0 mm or less) (see, for example, Patent Document 3).
However, in such a fluorescent tube, when the preheating current is set to an appropriate value as in the method described in Patent Document 2, no cathode bright spot is generated. This is because when the lamp current is large, the number of thermionic electrons emitted from the electrode is insufficient, so that the electrode is subjected to ion bombardment, and the lamp current is supplemented by secondary electrons. This is because the location where the temperature rises is observed as a cathode bright spot. That is, the technique described in Patent Document 2 optimizes the bright spot temperature to minimize both the electron bombardment and the evaporation of the electron-emitting substance due to the temperature rise.

On the other hand, in the case of lighting with a relatively low lamp current in a smaller fluorescent tube, it is considered that no cathodic luminescent spot is generated because all the lamp current can be covered by thermionic radiation from the electrodes above a certain preheating current. . In other words, in the case of lighting with a relatively low lamp current (for example, 100 mA or less) in a smaller fluorescent tube (for example, an outer diameter of 5.0 mm or less), it is possible to extend the life from another viewpoint, not to generate a cathode bright spot. It is necessary to plan for optimization. In particular, in a smaller fluorescent tube, the current density per unit area of the coil (filament) constituting the fluorescent lamp tends to be high, which may lead to a shortened life. In addition, the allowable current density varies depending on the shape of the electrode.
JP-A-1-35848 Japanese Patent Laid-Open No. 6-111762 JP 2005-235749

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a fluorescent lamp that has a longer fluorescent lamp life while having a smaller fluorescent tube, and a light source device including the fluorescent lamp, It is an object of the present invention to provide a display device including the light source device and a fluorescent lamp lighting method capable of extending the life.

The fluorescent lamp according to the present invention is a fluorescent lamp in which an inert gas and mercury are enclosed in a glass tube, and electrodes provided at both ends of the glass tube are arranged in the longitudinal direction of the tube axis of the glass tube The electron emission material is deposited on at least a part of the core wire, the outer diameter of the glass tube is 5.0 mm or less, and the electron emission of the core wire is The deposition area on which the substance is deposited is 1 mm ² or more and less than 50 mm ² .

A light source device according to the present invention is a light source device including a fluorescent lamp, wherein the fluorescent lamp is a fluorescent lamp in which an inert gas and mercury are sealed inside a glass tube, and both end portions of the glass tube The electrode provided on the electrode has a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, an electron-emitting substance is deposited on at least a part of the core wire, and the outer diameter of the glass tube is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting material is deposited is 1 mm ² or more and less than 50 mm ² .

A display device according to the present invention is a display device including a fluorescent lamp, wherein the fluorescent lamp is a fluorescent lamp in which an inert gas and mercury are sealed inside a glass tube, and both end portions of the glass tube The electrode provided on the electrode has a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, an electron-emitting substance is deposited on at least a part of the core wire, and the outer diameter of the glass tube is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting material is deposited is 1 mm ² or more and less than 50 mm ² .

A fluorescent lamp lighting method according to the present invention is a fluorescent lamp lighting method in which an inert gas and mercury are sealed inside a glass tube, and the fluorescent lamp has electrodes provided at both ends of the glass tube. The glass tube has a core wire arranged in a spiral shape with the tube axis as a longitudinal direction, an electron emitting material is deposited on at least a part of the core wire, and the outer diameter of the glass tube is 5.0 mm or less. The area of the core wire on which the electron-emitting substance is applied is 1 mm ² or more and less than 50 mm ² , and the fluorescent lamp is turned on continuously with respect to the electrodes by a high-frequency inverter. After flowing, the lamp current starts at 100 mA or less.

According to the fluorescent lamp according to the present invention, the outer diameter of the glass tube is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting material is deposited is 1 mm ² or more and less than 50 mm ^2. Therefore, the luminous efficiency is improved.

According to the light source device of the present invention, the outer diameter of the glass tube of the fluorescent lamp is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting substance is deposited is 1 mm ² or more and less than 50 mm ² . Therefore, at least one of high luminance and power saving can be achieved by improving the luminous efficiency of the fluorescent lamp.

According to the display device of the present invention, the outer diameter of the glass tube of the fluorescent lamp is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting substance is deposited is 1 mm ² or more and less than 50 mm ^2. Therefore, at least one of high brightness and power saving can be achieved by improving the luminous efficiency of the fluorescent lamp.

According to the lighting method of the fluorescent lamp according to the present invention, the outer diameter of the glass tube of the fluorescent lamp is 5.0 mm or less, and the deposition area of the core wire on which the electron-emitting substance is deposited is 1 mm ² or more and 50 mm. It is less than ² , and after the preheating current is continuously supplied to the electrode by the high frequency inverter, the lighting of the fluorescent lamp is started at a lamp current of 100 mA or less, thereby extending the life of the fluorescent lamp.

  Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment of fluorescent lamp and embodiment of lighting method of fluorescent lamp>
First, an embodiment of a fluorescent lamp and an embodiment of a lighting method of the fluorescent lamp according to the present invention will be described.
1A and 1B are a schematic cross-sectional view of a fluorescent lamp according to the present embodiment and a schematic cross-sectional view of a main part of the fluorescent lamp, respectively.

As shown in FIG. 1A, the fluorescent lamp 1 according to the present embodiment is a hot cathode fluorescent lamp, and electrodes 3 are provided at both ends of an elongated glass tube 2 having a cylindrical cross section.
In the present embodiment, a glass tube 2 having an outer diameter of 5.0 mm or less is used as a thickness that can cope with the above-described thinning of the display device. In addition, since it is necessary to provide the electrode 3 (especially coil part) inside, an outer diameter shall be at least 1.4 mm or more.
The phosphor 2a is applied to the inner surface of the glass tube 2 in a predetermined range, and the inside of the glass tube 2 emits an inert gas (rare gas) such as argon (Ar) or neon (Ne) and light emission. The substance mercury (Hg) is enclosed.

As shown in FIG. 1B, the electrode 3 includes a heater 4 including a coil portion 4a and a first lead portion 4b and a second lead portion 4c connected to the coil portion 4a.
In the present embodiment, the heater 4 has a core wire including at least one of tungsten (W) and rhenium-tungsten alloy (Re-W). Among these, a core wire mainly composed of rhenium-tungsten is particularly preferable because it has excellent strength during heating.

Moreover, as an example of the electron emission material 3a covering the heater 4, a ternary alkaline earth metal oxide composed of barium (Ba), strontium (Sr), and calcium (Ca) can be cited. The electron emitting material 3a may be a binary barium oxide. Alternatively, as is generally known as an electron emitting material for a hot cathode fluorescent lamp, about 1 to 5% by weight of zirconium oxide may be added to the alkaline earth metal oxide described above.
In addition, in this embodiment whose outer diameter of the glass tube 2 is 5.0 mm or less, it is preferable that the deposition area of the core wire to which the electron-emitting substance is deposited is 1 mm ² or more and 50 mm ² or less. It is larger than 50 mm ^2, while it is difficult to fit the width of the narrow frame for necessary to increase the length of the electrode (the length of the coil portion 4a) as described above occurs, 1 mm ² less than In some cases, the current density becomes extremely high, leading to a shortened life.

  FIG. 2A and FIG. 2B are a perspective view seen from the front end side and a perspective view seen from the rear end side, respectively, showing the configuration of the electrode 3 of the fluorescent lamp 1 according to this embodiment. FIG. 2C is a schematic configuration diagram of the heater 4 (coil 4 a) provided on the electrode 3.

In the fluorescent lamp 1 according to the present embodiment, the electrode 3 includes a first heater tab 5a and a second heater tab 5b that support the heater 4, as shown in FIG. 2A. The first heater tab 5a is a first connecting member, and the rear end side of the first lead portion 4b of the heater 4 is connected by welding. The second heater tab 5b is a second connecting member, and the rear end side of the second lead portion 4c is connected by welding.
The first heater tab 5a and the second heater tab 5b are plate materials made of, for example, stainless steel (SUS304). As will be described later with reference to the manufacturing method, when the electrode 3 is manufactured, the first heater tab 5a and the second heater tab 5b function as a connection reinforcing member as a single body and are separated during the manufacturing process.

As shown in FIG. 2B, the electrode 3 is connected to the first introduction line 6a and the second introduction line 6b (see FIG. 1B) via the first heater tab 5a and the second heater tab 5b. The first introduction line 6a and the second introduction line 6b are provided at both ends of the glass tube 2, are substantially parallel to each other, and penetrate the end of the glass tube 2 from the outside to the inside.
The first heater tab 5a is connected by welding to the tip side of the portion of the first introduction line 6a that extends into the glass tube 2, and the portion of the second introduction line 6b that extends into the glass tube 2 is welded. The second heater tab 5b is connected to the distal end side by welding.

Thus, the electrode 3 supported by the first introduction line 6a and the second introduction line 6b is arranged such that the coil portion 4a of the heater 4 has the tube axis of the glass tube 2 as the longitudinal direction. For this reason, the ions generated by the discharge mainly collide with the tip of the coil part 4a, and the side surface of the coil part 4a has a configuration in which the scattering of the electron-emitting material 3a due to the collision of ions is difficult to occur.
In addition, since the heater 3 is supported on the lead-in wire by the two lead portions extending from the rear end side of the coil portion 4a, the electrode 3 has a configuration in which no tension is applied to the heater 4, and a disconnection is hardly generated. .

Furthermore, in this embodiment, the electrode 3 is provided with the sleeve 7 to prevent the electron emitting material 3a from being scattered or evaporated. The sleeve 7 is an example of a scattering prevention member and is made of nickel (Ni), molybdenum (Mo) or the like, and has a cylindrical shape with both ends opened.
The sleeve 7 is inserted inside in such a direction that the coil portion 4 a of the heater 4 is substantially parallel, and is attached to the first heater tab 5 a by the sleeve lead 8. Thereby, the sleeve 7 covers the circumference | surroundings of the coil part 4a in the form which open | released the front end side and the rear end side of the coil part 4a.
The sleeve lead 8 is made of, for example, stainless steel (SUS304) in the same manner as the first heater tab 5a and the second heater tab 5b. In this example, the sleeve lead 8 is fixed to the first heater tab 5a. However, the sleeve lead 8 may be fixed to the second heater tab 5b.

Here, the inner diameter of the sleeve 7 is larger than the outer diameter of the coil portion 4 a of the heater 4, and when the coil portion 4 a of the heater 4 is inserted inside the sleeve 7 in a substantially parallel orientation, the coil portion 4 a Configured not to touch.
The outer diameter of the sleeve 7 is smaller than the inner diameter of the glass tube 2 and is configured so that the sleeve 7 and the glass tube 2 do not contact each other.

  Further, the mounting position of the sleeve 7 is set so that the distal end portion of the coil portion 4a does not protrude from the opening end surface 7a of the sleeve 7. In addition, the positional relationship between the sleeve 7 and the heater 4 is preferably a positional relationship in which the tip end portion of the coil portion 4a enters inside from the opening end surface 7a of the sleeve 7, but the opening end surface 7a of the sleeve 7 and the tip portion of the coil portion 4a are desirable. May be located on the same plane.

Further, the length of the sleeve 7 is made longer than the length of the coil portion 4 a, and the entire side surface of the coil portion 4 a is covered with the sleeve 7.
The application range of the phosphor 2 a on the inner surface of the glass tube 2 described above is set to a position slightly outside the opening end surface 7 a of the sleeve 7 of the electrode 3. A range where the phosphor 2 a is applied becomes a light emitting portion of the fluorescent lamp 1.

In the present embodiment, as shown in FIG. 2C, for example, the core wire constituting the heater 4 has a configuration in which finer spiral structures are arranged in a spiral shape as a whole while being in non-contact with each other.
In other words, in the present embodiment, the coil portion 4a of the heater 4 is roughly formed as a substantially cylindrical coil portion 4a by a double spiral (so-called double helical shape) core wire. As shown in FIG. 2B, two lead portions 4b and 4c extend outward from the rear end of the coil portion 4a.
Thus, if the coil part 4a is made into a double helix shape, since the substantial full length of the core wire which forms the coil part 4a becomes long, the surface area of the coil part 4a can be increased. Thereby, the quantity of the electron emission substance 3a apply | coated to the coil part 4a can be increased.

Although not shown, the coil part 4a may have a so-called triple helical shape having a triple helical shape. Moreover, the coil part 4a may be a single helical shape in which a core wire is simply spirally wound. However, if the heater 4 has a triple spiral shape, the diameter of the coil portion 4a increases, so that in order to reduce the diameter of the glass tube 2 and ensure the substantial length of the coil portion 4a, the heater 4 is A double spiral shape is desirable.
In any of the spiral shapes, the overall shape of the core wire (that is, the overall shape of the coil portion 4a) is the longitudinal direction of the tube axis of the glass tube 2 so that the longitudinal direction in FIG. Arranged as.

As a specific configuration example of such a fluorescent lamp 1, a phosphor excited by ultraviolet rays is applied to the inner wall of a glass tube 2 having an outer diameter of 2.0 mm and an inner diameter of 1.6 mm, and an electron is applied to both ends of the glass tube 2. By sealing the coil-shaped electrode 3 made of a core of Re-W coated with the emission material 3a, the inert gas and mercury are supplied at a predetermined pressure (for example, 25 to 40 Torr) and an amount (for example, 2 to 3 mg). ) Can be given as an example.
Further, as a specific configuration example of the electrode 3, with respect to the core wire by Re-W, the core wire diameter is 0.017 mm, the primary mandrel diameter (a in FIG. 2C) is 0.08 mm, the primary turn number is 170 turns, and the secondary mandrel. Diameter (b in FIG. 2C) 0.4 mm, primary pitch (c in FIG. 2C) 0.04 mm, secondary pitch (d in FIG. 2C) 0.6 mm, outer diameter 0.65 mm, total length 1 The structure which has a coil part 4a of .9 mm can be mentioned. In this configuration, the electron-emitting material 3a is dipped and sprayed onto at least a part of the core wire, thereby forming a double helical coil portion 4a having an outer diameter of 0.9 mm.

FIG. 3 is an explanatory diagram showing the temperature dependence of the electron emission capability measured with an example of the fluorescent lamp according to the present embodiment. In this measurement, the surface area of the electron emitting material was 4.6 mm ² .
From the results of FIG. 3, when this fluorescent lamp is used at a lamp current of 10 mArms, the average current density at the electrode is 0.12 A / cm ^2. To obtain this, the electron emission capability at 600 ° C. is required. It became clear that it was necessary.

  FIG. 4 is an explanatory diagram showing the relationship between Rh / Rc and the core temperature according to the material change of the coil core wire in an example of the fluorescent lamp according to the present embodiment. Rh represents the resistance value of the coil when a preheating current is passed through the coil, and Rc represents the resistance value of the coil at room temperature. In both the core wire of tungsten (W) and the core wire of rhenium-tungsten alloy (Re-W), the resistance value increases as the temperature rises.

Therefore, in the case of the electrode shape and the lamp current in the example in which the measurement of FIG. 3 is performed, for example, in a rhenium-tungsten alloy, if Rh / Rc is set to 2.7 or more as a preheating condition, the temperature can be set to 600 ° C. or more. The lamp current can be covered by thermionic electrons.
On the other hand, the electron-emitting material is generally composed of a ternary eutectic oxide of BaO—SrO—CaO. However, since this electron-emitting material becomes extremely hot and BaO evaporates over time, it is depleted. It becomes a factor of the conversion. Therefore, a practically acceptable range is 800 ° C. or lower, and Rh / Rc is 3.3 or lower.

Therefore, when the core wire contains an alloy of rhenium and tungsten, it is considered preferable to select a preheating current value in a range of 2.7 ≦ (Rh / Rc) ≦ 3.3.
Similar to the case where the core wire includes an alloy of rhenium and tungsten, the preheating current value in the range of 3.8 ≦ (Rh / Rc) ≦ 4.8 in the case where the core wire includes a single tungsten. It is considered preferable to select.

Next, an embodiment of a fluorescent lamp lighting method according to the present invention will be described.
In the present embodiment, description will be given by taking as an example the case of using the fluorescent lamp 1 according to the above-described embodiment.

First, the basic operation of the fluorescent lamp 1 according to this embodiment will be described.
As an operation, first, in order to apply a voltage between the lead portions 4b and 4c of the heater 4 constituting each electrode 3, for example, a voltage of about 5V between the first introduction line 6a and the second introduction line 6b. And the electron emission material 3a is heated by a preheating current. Thereby, thermoelectrons are emitted from the electron emission material 3a. After heating, a voltage of about 300 V, for example, is applied between the electrodes 3 at a high frequency using an inverter. If the tube diameter (outer diameter) is 5.0 or less, the luminance is saturated even if the lamp current is 100 mA or more, and therefore the lamp current is 100 mA or less.

By applying a voltage, electrons are emitted from the electron emitting material 3 a and arc discharge occurs between the electrodes 3. In addition, after an arc discharge is generated between the electrodes 3, a preheating current is continuously applied by applying a voltage of about 100V between the electrodes 3 and applying a voltage of about 2V to each electrode 3, for example. Shed.
Electrons emitted from the electron emitting material 3a are accelerated by arc discharge, collide with mercury atoms, and excite mercury atoms. Excited mercury atoms emit ultraviolet light. The ultraviolet lamp is converted into visible light by the phosphor 2a, whereby the fluorescent lamp 1 emits light.

  In addition, although the ion which generate | occur | produced during discharge collides with the electrode 3 and becomes a factor which scatters the electron emission substance 3a, since the coil part 4a is arrange | positioned by making the direction along the tube axis of the glass tube 2 into a longitudinal direction, Ions mainly collide with the tip of the coil portion 4a. For this reason, scattering of the electron-emitting material 3a is suppressed in most of the side surfaces of the coil portion 4a. On the other hand, since the coil portion 4a is inserted into the sleeve 7 and the open end surface 7a of the sleeve 7 protrudes from the tip portion of the coil portion 4a, collision of ions with the tip portion of the coil portion 4a is also reduced. Thereby, depletion of the electron emission material 3a can be suppressed over a long period of time. Therefore, the electrode 3 can emit electrons over a long period of time, and the life of the fluorescent lamp 1 can be extended.

  The electron emitting material 3 a evaporates due to the heating of the heater 4, but if the sleeve 7 is not provided, the evaporated electron emitting material 3 a is deposited on the inner surface of the glass tube 2. On the other hand, when the coil portion 4 a is inserted into the sleeve 7, the electron emission material 3 a evaporated from the heater 4 is vapor deposited on the inner surface of the sleeve 7. When the heater 4 is heated, the sleeve 7 is also heated, and electrons are emitted from the electron-emitting material 3a adhering to the sleeve 7, so that the life of the fluorescent lamp 1 is extended by extending the life of the electrode 3. Can be planned.

  Further, since the heater 4 is inserted into the sleeve 7, it is possible to generate heat radiation, so that the heater 4 can be heated to a desired temperature at a low voltage. For example, the voltage applied during preheating can be lowered from, for example, about 5V to, for example, about 3V. In addition, when the coil part 4a and the sleeve 7 are contacting, since the temperature fall of the heater 4a may be caused, the structure which makes the coil part 4a and the sleeve 7 non-contact is more preferable.

Next, based on the basic operation described above, a specific lighting method of the fluorescent lamp 1 according to the present embodiment will be described.
FIG. 5 is a block diagram showing an example of a fluorescent lamp lighting circuit for explaining the lighting method of the fluorescent lamp according to the present embodiment.

In the present embodiment, the fluorescent lamp lighting circuit 14 includes a fluorescent lamp 1, a fluorescent tube lighting circuit 15, a lighting switch 16, and a filament preheating circuit 17.
The lighting switch 15 is a switch of a lighting device, and a DC voltage is output by operation. The filament preheating circuit 17 is connected to the coils (filaments) at both ends of the fluorescent lamp 1 and is operated by the lighting switch 16 to generate an alternating voltage (Vf). The preheating current (If) is applied to each coil (filament). ).

FIG. 6 is an explanatory diagram showing the relationship between the lamp current and Rh / Rc according to the change in the preheating current in the fluorescent lamp according to the present embodiment.
In the case of the electrode shape in the example of the measurement shown in FIG. 3 described above, when Rc = 21.4Ω and the lamp current is 10 mArms, when the lamp is turned on, as a preheating condition, an AC voltage (Vf) of 3.6 V is applied by a high frequency inverter. It was confirmed that the preheating current (If) flows 58 mA. Accordingly, since Rh is 62Ω, Rh / Rc is 2.9. The value of Rh / Rc corresponds to 665 ° C. from the result of FIG.

As described above, the fluorescent lamp 1 is turned on by continuously supplying a preheating current to the electrodes by the high-frequency inverter, and then turning on at a lamp current of 100 mA or less, thereby realizing a long life.
According to these (Rh / Rc), in this example, a preheating current of 52 to 64 mA can be obtained as an appropriate preheating current.

  Here, the manufacturing method of the fluorescent lamp 1 mentioned above is demonstrated with reference to FIGS.

First, as a first winding step, as shown in FIG. 7A, for example, a rhenium-tungsten core wire (wire) 9 is wound around a molybdenum core wire 10 to obtain a fine spiral structure. Subsequently, as a second winding step, as shown in FIG. 7B, a core wire 10 around which a core wire 9 is wound is wound in a spiral shape larger than the fine spiral structure described above, thereby forming a substantially cylindrical shape with a double spiral. The coil portion 4a is formed, and the two lead portions 4b and 4c extend from the rear end of the coil portion 4a.
Here, in the coil part 4a, it is set as the shape which the adjacent core wires 9 do not contact. In these winding steps, the heater 4 whose shape is held by the core wire 10 is created. Note that this winding step may include a step of removing distortion of the core wire 9 by heat treatment.

Thereafter, a heater tab welding process is performed. In this step, as shown in FIG. 7C, the heater 4 is welded to the heater tab 5 of the connection reinforcing member, which includes the first and second heater tabs 5a and 5b.
Here, each of the first heater tab 5a and the second heater tab 5b has an L-shaped cross-sectional shape, the L-shaped short side is connected by a connecting portion 5c, and the first heater tab 5a and the second heater tab 5b are connected to each other. It is united. In addition, a separation groove is provided between the first heater tab 5a and the second heater tab 5b, but this separation is not complete until it is cut later, and therefore the first heater tab 5a. And the second heater tab 5b are partially connected.

In this heater tab welding process, the rear end side of the first lead portion 4b of the heater 4 is welded to the first heater tab 5a of the heater tab 5 integrated. Further, the rear end side of the second lead portion 4c of the heater 4 is welded to the second heater tab 5b.
Thereby, the heater assembly 11 in which the heater 4 and the heater tab 5 are integrated is created. In this heater tab welding process, since the shape of the heater 4 is held by the core wire 10, the shape is not lost.

After the heater tab welding process, a melting process is performed.
In this step, as shown in FIG. 7D, the molybdenum core wire 10 around which the rhenium-tungsten core wire 9 is wound is melted. For example, the heater assembly 11 is immersed in a mixed acid solution of sulfuric acid and nitric acid to dissolve the molybdenum core wire 10. Here, since rhenium-tungsten and stainless steel are not dissolved in the mixed acid solution, the heater 4 and the heater tab 5 remain as they are.
The heater 4 is weakened against the external force by melting the molybdenum core wire 10. However, the heater 4 has the first lead portion 4 b and the second lead portion 4 c supported by the integrally structured heater tab 5. As a result, the heater assembly 11 as a whole has a sufficient strength and does not lose its shape during work.

A coating process is performed after a dissolution process.
In this step, as shown in FIG. 8A, the electron emitting material 3a is applied to the heater 4. In this example, ternary barium oxide (Ba, Sr, Ca) CO ₃ is applied to the heater 4.
The electron emission material 3a can be applied by, for example, a spraying method. In the spraying method, for example, the electron emitting material 3a can be applied to the inside of the coil portion 4a with a uniform density by spraying the electron emitting material 3a onto the heater 4 while rotating the heater assembly 11.

Further, the application of the electron emitting material 3a may be a dip method. That is, the electron emission material 3a can be applied to the coil portion 4a by immersing the heater 4 of the heater assembly 11 in a tank containing the electron emission material 3a.
Here, (Ba, Sr, Ca) CO ₃ applied to the heater 4 changes to (Ba, Sr, Ca) O by heating during the manufacturing process. In addition, as for the film thickness of the electron emission material 3a apply | coated to the coil part 4a, about 30-60 micrometers is desirable.

A sleeve welding process is performed after an application | coating process.
In this step, first, the sleeve lead 8 is welded to the sleeve 7 as shown in FIG. 8B. Thereby, the sleeve assembly 12 in which the sleeve 7 and the sleeve lead 8 are integrated is created. A process of removing heat and dirt from the sleeve assembly 12 by heat treatment may be added.
Subsequently, as shown in FIG. 8C, the heater assembly 11 and the sleeve assembly 12 after the application of the electron-emitting material 3a are connected. Specifically, first, the coil portion 4 a of the heater 4 is inserted into the sleeve 7. At this time, in a state where the sleeve lead 8 is aligned with the first heater tab 5 a, alignment is performed so that the side surface of the coil portion 4 a does not contact the inner surface of the sleeve 7. Further, alignment is performed so that the tip of the coil portion 4 a is inside the opening end surface 7 a of the sleeve 7. Then, the sleeve lead 8 is connected to the first heater tab 5a by welding. Thereby, the heater assembly 11 and the sleeve assembly 12 are united.

The lead wire welding process is performed after the sleeve welding process.
In this step, as shown in FIG. 9A, the heater assembly 11 that has been completed up to the attachment of the sleeve assembly 12 is connected to the first introduction line 6a and the second introduction line 6b.
Specifically, first, the first introduction line 6 a and the second introduction line 6 b are integrated by the stem glass 13. The first introduction line 6a and the second introduction line 6b are supported by the stem glass 13 at a predetermined interval so as not to contact each other. Then, the first introduction line 6a and the first heater tab 5a are connected by welding, and the second introduction line 6b and the second heater tab 5b are connected by welding.

By the way, if the distance between the first lead portion 4b and the second lead portion 4c of the heater 4 and the distance between the first lead wire 6a and the second lead wire 6b supported by the stem glass 13 are different, the lead If the part and the lead-in wire are to be directly connected, bending is required.
On the other hand, a bending process becomes unnecessary by connecting a lead part and an introductory line via the 1st heater tab 5a and the 2nd heater tab 5b. In addition, the alignment is facilitated by welding the lead portion and the lead-in wire to the plate-like heater tab. Further, the connection strength is improved.

After the lead wire welding process, a cutting process is performed.
In this step, the connecting portion 5c of the heater tab 5 described above is cut with a laser or the like. Since the heater tab 5 has a separation groove formed in advance between the first heater tab 5a and the second heater tab 5b, the first heater tab 5a and the second heater tab 5b are cut when the connecting portion remaining before cutting is cut. A gap is formed between the two, and they are electrically independent.
Through the above steps, the electrode 3 is completed as shown in FIG. 9B.

<Embodiments of light source device and display device>
Embodiments of a light source device and a display device according to the present invention will be described.
In the present embodiment, a case where a light source device including a fluorescent lamp constitutes a display device as a backlight will be described as an example.

FIG. 10 shows a schematic configuration diagram of a display device having the light source device according to the present embodiment.
The display device 21 according to this embodiment includes a light source device 22 and an optical device 23.

In the present embodiment, the light source device 22 is a direct-type backlight device provided on the back surface of the optical device 23 having a liquid crystal device.
In the light source device 22, the above-described fluorescent lamp 1 is provided in the resin light guide 26.
In the present embodiment, a diffusion sheet 29 is provided at the closest portion of the light source device 22 facing the optical device 23. The diffusion sheet 29 uniformly guides light from the blue light source and each phosphor to the optical device 23 side in a planar shape. A reflector 24 is provided on the back side of the light source device 22. Further, if necessary, a reflector 25 similar to the reflector 24 is also provided on the side surface of the light guide unit 26.
In the light source device 22 according to the present embodiment, the resin constituting the light guide unit 26 can use various transparent resins in addition to epoxy, silicone, and urethane. Further, the shape of the blue light source constituting the light emitter 6 can be appropriately selected from various types such as a side emitter type and a shell type.

On the other hand, in the present embodiment, the optical device 23 is a liquid crystal device that outputs predetermined output light by modulating light from the light source device 22.
In this optical device 23, from the side close to the light source device 22, the deflection plate 30, the glass substrate 31 for TFT (Thin Film Transistor) and the dot-like electrode 32 on the surface, the liquid crystal layer 33 and the front and back thereof. The deposited alignment film 34, electrodes 35, a plurality of black matrices 36 on the electrodes 35, and first (red) color filters 37a and second (green) corresponding to pixels provided between the black matrices 36. A color substrate 37 and a third color filter 37c, a glass substrate 38 provided apart from the black matrix 36 and the color filters 37a to 37c, and a deflection plate 39 are arranged in this order.
Here, the deflecting plates 30 and 39 form light that vibrates in a specific direction. The TFT glass substrate 31, the dot electrode 32, and the electrode 35 are provided for switching the liquid crystal layer 33 that transmits only light oscillating in a specific direction, and an alignment film 34 is also provided. Thus, the inclination of the liquid crystal molecules in the liquid crystal layer 33 is aligned in a certain direction. Further, since the black matrix 36 is provided, the contrast of light output from the color filters 37a to 37c corresponding to the respective colors is improved. The black matrix 36 and the color filters 37a and 37c are attached to the glass substrate 38.

In the light source device 22, the display device 21 according to the present embodiment can achieve at least one of high luminance and power saving by improving the light emission efficiency of the fluorescent lamp.
In the display device 21 according to the present embodiment, the coil portion of the fluorescent lamp 1 is arranged in a spiral shape with the tube axis of the glass tube as the longitudinal direction, so that the diameter of the glass tube 2 can be reduced. Therefore, even when the fluorescent lamp 1 is used for a direct type backlight, the display of the display device 21 can be thinned. In addition, since the coil portion 4a can secure a length that allows a sufficient amount of the electron emitting material 3a to be applied, the life can be extended even if the diameter of the glass tube 2 is reduced.

As described above, according to the fluorescent lamp according to the present embodiment, the luminous efficiency of the fluorescent lamp can be improved and the life can be extended.
In addition, according to the light source device, the display device, and the fluorescent lamp lighting method according to the present embodiment, at least one of high luminance and low power consumption can be achieved by increasing the luminous efficiency of the fluorescent lamp.

In the above-described embodiment, an example of the direct type has been described. However, an edge light type light source device and a display device are advantageous in terms of thinning, and thus are used for a display for a personal computer (for example, a notebook type). On the other hand, the number of fluorescent lamps provided is extremely small compared to the direct type.
Therefore, in the edge light type light source device and display device, when the fluorescent lamp according to the present embodiment is provided, it is particularly effective because the performance improvement of this small fluorescent lamp directly leads to the performance improvement of the entire device. Conceivable.

  Although the embodiments of the present invention have been described above, the materials used in the description and the numerical conditions such as the amount, processing time, and dimensions are only suitable examples, and the dimensional shape and arrangement in each drawing used for the description. The relationship is also schematic. That is, the present invention is not limited to this embodiment.

  For example, in the above-described embodiment, the case of the direct method is described as an example. However, the light source device and the display device according to the present embodiment are not limited to this, and an edge light method may be used. The edge light method may be a backlight type in which the position of the light source device is on the back side, or the position of the light source device is on the surface side, and reflection or semi-transmission in the optical element (hybrid of reflection and transmission) It may be a front light type using reflected light generated by the above.

  Further, for example, in the present embodiment, the case where the light source device and the display device are configured by the fluorescent lamp has been described as an example. However, the fluorescent lamp according to the present embodiment may include other fluorescent lamps such as a scanner. The present invention can be variously modified and changed such that an electronic device can be configured.

A and B are a schematic cross-sectional view and a schematic cross-sectional view of the main part, showing the configuration of an example of a fluorescent lamp according to the present invention. AC is a perspective view viewed from the front end side, a perspective view viewed from the rear end side, and a schematic configuration diagram of a coil provided on this electrode, each showing a configuration of an example of an electrode of a fluorescent lamp according to the present invention. is there. It is explanatory drawing which shows the temperature dependence of the electron emission capability in an example of the fluorescent lamp which concerns on this invention. It is explanatory drawing which shows the relationship between Rh / Rc and core wire temperature according to the change of coil core wire quality in an example of the fluorescent lamp which concerns on this invention. It is a block diagram of a fluorescent lamp lighting circuit for explaining an example of a lighting method of a fluorescent lamp according to the present invention. It is explanatory drawing which shows the relationship between a lamp current and Rh / Rc according to the change of the preheating current in an example of the fluorescent lamp which concerns on this invention. AD is process drawing (the 1) with which it uses for description of an example of the manufacturing method of the fluorescent lamp which concerns on this invention. AC is process drawing (the 2) with which it uses for description of an example of the manufacturing method of the fluorescent lamp which concerns on this invention. FIGS. 3A and 3B are process diagrams (part 3) for explaining an example of the manufacturing method of the fluorescent lamp according to the present invention. FIGS. It is a schematic block diagram which shows the structure of an example of the light source device and display apparatus which concern on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fluorescent lamp, 2 ... Glass tube, 2a ... Phosphor screen, 3 ... Electrode, 3a ... Electron emission substance, 4 ... Heater, 4a ... Coil part, 4b ..First lead portion, 4c ... second lead portion, 5 ... heater tab, 5a ... first heater tab, 5b ... second heater tab, 6a ... first introduction 6b ... second lead wire, 7 ... sleeve, 7a ... open end face, 8 ... sleeve lead, 9 ... core wire (wire), 10 ... core wire, 11 ... Heater assembly, 12 ... sleeve assembly, 13 ... stem glass, 14 ... fluorescent lamp lighting circuit, 15 ... fluorescent tube lighting circuit, 16 ... lighting switch, 17 ... filament preheating circuit , 21 ... display device, 22 ... light source device, 23 ... optical device, 2 ... Reflector, 25 ... Reflector, 26 ... Light guide, 29 ... Diffusion sheet, 30 ... Deflecting plate, 31 ... TFT glass substrate, 32 ... Dot electrode, 33. ..Liquid crystal layer, 34... Alignment film, 35... Electrode, 36... Black matrix, 37 a... First color filter, 37 b. Filter, 38 ... glass substrate, 39 ... deflecting plate

Claims (8)

A fluorescent lamp in which an inert gas and mercury are enclosed in a glass tube,
The electrodes provided on both ends of the glass tube have a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, and an electron-emitting substance is deposited on at least a part of the core wire,
The outer diameter of the glass tube is 5.0 mm or less,
The fluorescent lamp, wherein an area of the core wire on which the electron-emitting substance is applied is 1 mm ² or more and less than 50 mm ² . The fluorescent lamp according to claim 1, wherein the core wire constitutes the spiral arrangement by a spiral structure finer than the spiral shape. The fluorescent lamp according to claim 1, wherein the core wire includes an alloy of rhenium (Re) and tungsten (W). A light source device comprising a fluorescent lamp,
The fluorescent lamp is
A fluorescent lamp in which an inert gas and mercury are enclosed in a glass tube,
The electrodes provided on both ends of the glass tube have a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, and an electron-emitting substance is deposited on at least a part of the core wire,
The outer diameter of the glass tube is 5.0 mm or less,
The light source device, wherein a deposition area of the core wire on which the electron-emitting substance is deposited is 1 mm ² or more and less than 50 mm ² . A display device comprising a fluorescent lamp,
The fluorescent lamp is
A fluorescent lamp in which an inert gas and mercury are enclosed in a glass tube,
The electrodes provided on both ends of the glass tube have a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, and an electron-emitting substance is deposited on at least a part of the core wire,
The outer diameter of the glass tube is 5.0 mm or less,
A display device, wherein the core wire has a deposition area on which the electron-emitting substance is deposited of 1 mm ² or more and less than 50 mm ² . A method for lighting a fluorescent lamp in which an inert gas and mercury are enclosed in a glass tube,
In the fluorescent lamp, electrodes provided at both ends of the glass tube have a core wire arranged in a spiral shape with the tube axis of the glass tube as a longitudinal direction, and an electron-emitting substance is formed on at least a part of the core wire. Be deposited,
The outer diameter of the glass tube is 5.0 mm or less,
An area of the core wire where the electron-emitting substance is applied is 1 mm ² or more and less than 50 mm ² ;
The fluorescent lamp lighting method, wherein after the preheating current is continuously supplied to the electrode by a high-frequency inverter, the fluorescent lamp is started at a lamp current of 100 mA or less. The core includes tungsten;
The fluorescent lamp lighting method according to claim 6, wherein the value of the preheating current is selected in a range of 3.8 ≦ (Rh / Rc) ≦ 4.8.
(However, Rh is the resistance value of the coil when a preheating current is passed through the coil, and Rc is the resistance value of the coil at room temperature.) The core wire includes an alloy of rhenium and tungsten,
The fluorescent lamp lighting method according to claim 6, wherein the value of the preheating current is selected in a range of 2.7 ≦ (Rh / Rc) ≦ 3.3.

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