JP2006302575A - Lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lamp wherein an electrode acts as a light emitting part to emit light, and a high light output and a long service life are attained at the same time, by heating a pair of electrodes disposed in an arc tube instead of a filament always causing a problem such as disconnection. <P>SOLUTION: In this lamp, a pair of the electrodes 3 are disposed face to face in the arc tube 1, and a rare gas and halogen are filled in the arc tube 1. The electrodes 3 are heated by discharge and act as light emitting parts. Emission from the electrodes 3 is larger than emission of the rare gas. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lamp in which an electrode disposed in an arc tube serves as a light emitting portion to emit light.

Conventionally, it is well known that when an object is heated to high temperature, it emits light with a radiation spectrum that approximates blackbody radiation.
In particular, tungsten, which has a high melting point among metals and has a low vapor pressure, is widely used as a light emitting part of an incandescent lamp in order to make it a thin linear filament, which can be heated to a high temperature and emit light efficiently.

  Such an incandescent lamp becomes brighter as the filament temperature rises and can achieve higher output, but at the same time, the amount of evaporation of tungsten also increases, so that the arc tube becomes black or the filament is thinned and broken.

  In order to solve such a problem, a halogen such as bromine or iodine is sealed in the arc tube. Even if tungsten evaporates from the high-temperature filament, it does not remain attached to the inner surface of the arc tube but can return to the filament and maintain the transparency of the arc tube.

However, tungsten does not accurately return to the original position where it has evaporated from the filament, and the thinned and thinned portion of tungsten becomes hotter than the other portions, and further thinned and eventually disconnected.
In other words, incandescent lamps that heat the filament to a high temperature and use it as the light-emitting part, the filament breaks in a short time when the filament is heated to a high temperature in order to obtain a high light output. There was a problem that I could not.

JP 2003-68253 A

  The present invention has been made in order to solve such a problem, and by replacing a filament in which the problem of disconnection always occurs, a pair of electrodes disposed in the arc tube is heated to a high temperature, so that the electrodes become a light emitting portion. Accordingly, it is an object of the present invention to provide a lamp that emits light and can simultaneously obtain high light output and long service life.

  The lamp according to claim 1 is a lamp in which a pair of electrodes are opposed to each other in an arc tube, and a rare gas and a halogen are enclosed in the arc tube, and the electrode is heated by discharge to form a light emitting portion. It is characterized by.

  The lamp according to claim 2 is the lamp according to claim 1, particularly characterized in that light emission from the electrode is larger than light emission of the rare gas.

The lamp according to claim 3 is the lamp according to claim 2, and in particular, the relationship between the surface area X (mm ² ) of the electrode and the lamp current Y (A) is 0.05 ≦ Y / X ≦. 5.0.

  The lamp according to claim 4 is the lamp according to any one of claims 1 to 3, and in particular, a high melting point member serving as another light emitting portion is disposed between the pair of electrodes. It is characterized by being.

  The lamp according to claim 5 is the lamp according to any one of claims 1 to 4, and in particular, the electrode and the high melting point member are tungsten of 99.99 wt% or more. It is characterized by.

  A lamp according to a sixth aspect is the lamp according to any one of the first to fifth aspects, wherein the electrode is substantially spherical.

  The lamp according to claim 7 is the lamp according to claim 1 or claim 4, wherein the electrode separation distance or the separation distance between the electrode and the high melting point member is 1 mm or less. Features.

  The lamp according to claim 8 is the lamp according to claim 1 or 4, wherein a halogen-resistant protective layer is formed on a part of the electrode and the high melting point member. To do.

  A lamp according to a ninth aspect is the lamp according to any one of the first to eighth aspects, wherein the electrode is lit beyond the melting point.

  According to the lamp of the present invention, the pair of electrodes arranged in the arc tube is heated to a high temperature instead of the filament in which the problem of disconnection always occurs, so that the electrodes are heated to become a light emitting portion and emit light. By maintaining the temperature at a high temperature, a high light output can be obtained and a long service life can be achieved.

The relationship between the surface area X (mm ² ) of the electrode and the lamp current Y (A) is 0.05 ≦ Y / X ≦ 5.0, so that the electrode can be reliably connected without melting and extinguishing instantaneously. Can emit light.

  By disposing a high melting point member to be another light emitting part between the pair of electrodes, the shape of the light emitting part can be changed to an arbitrary shape, and a light source can be designed according to the application.

  Since the electrode and the high-melting point member are high-purity tungsten of 99.99 wt% or more, impurities are not released from the electrode and the high-melting point member during lighting, and the halogen cycle can always function reliably, and light emission The blackening of the tube can be reliably suppressed.

  Since the electrode is almost spherical, even if the electrode temperature is close to the melting point or reaches the melting point during lighting, the electrode maintains a substantially spherical shape by surface tension and suppresses electrode wear. can do.

Since the electrode separation distance between the electrodes or the separation distance between the electrode and the high melting point member is 1 mm or less, the electric power input to the electrode contributes to the heating of the electrode or the high melting point member at a high rate. Can be efficiently heated.
Moreover, since the electrode separation distance or the separation distance between the electrode and the high melting point member is 1 mm or less, the light emitting portion can be made visually continuous.

  Since the halogen-resistant protective layer is formed on the non-light-emitting portion in the low temperature state, which is a part of the electrode and the high melting point member, the non-light-emitting portion is not eroded by the halogen enclosed in the arc tube. .

Even when the electrode is turned on beyond the melting point, the electrode shape can be maintained by the surface tension. Furthermore, since the electrode material returns to the electrode substantially uniformly by the halogen cycle, the electrode shape can be kept constant for a long time.
Further, the power input to the lamp can be maximized, and the luminous efficiency can be increased to the limit.

Hereinafter, the lamp of the present invention will be described with reference to the drawings.
FIG. 1 is an explanatory diagram of the lamp of the present invention.
A pair of tungsten electrode support rods 2 having a diameter of 0.3 mm are sealed in an arc tube 1 made of silica glass, and the tip of the electrode support rod 2 is made of tungsten having a maximum diameter of 0.5 mm. A spherical electrode 3 is formed.

The arc tube 1 has an internal volume of 0.2 cm ³ , and contains 400 torr of argon as a rare gas and 1.3 μmol of bromine as a halogen.

The electrode 3 may be formed in a substantially spherical shape by heating and melting the tip of the electrode support rod 2, or the electrode 3 formed in a substantially spherical shape in advance may be melt bonded to the electrode support rod 2.
The sealing structure between the electrode support rod 2 and the arc tube 1 may be any sealing structure such as a shrink seal or a pinch seal.

The distance between the electrodes of the pair of electrodes 3 is 0.7 mm, and when an electric power of 12 V, 2.5 A, 30 W is applied between the electrodes 3, a discharge occurs between the electrodes 3, and an arc generated by the discharge Further, the electrode 3 itself is heated by the current flowing through the electrode 3, the tungsten atoms constituting the electrode are thermally vibrated, and the energy is emitted as light by the thermal radiation. It will be. The luminous efficiency is 35 lumens / W.
The arc tube 1 is filled with argon, and the argon itself is heated by discharge to emit light.

In the lamp of the present invention, since tungsten is used for the electrode 3, the emissivity, which is the ratio to the black body radiation, is about 0.4. On the other hand, the argon present in the discharge space between the electrodes has a distance between the electrodes of 0.7 mm, and the arc tube during lighting is about 1 atm. Therefore, the argon present between the electrodes is converted into argon plasma. The emissivity is about 0.0001. Further, the temperature of the electrode during lighting is 3300K, the temperature of tungsten is 3300K, and the temperature of the argon plasma existing between the electrodes is 10000K.
When the emission intensity is compared based on the relationship between the emissivity of tungsten and argon plasma and the temperature of tungsten and argon plasma, the emission intensity is proportional to the fourth power of the emissivity and temperature. The emission intensity of 4 × 3300 ⁴ and argon plasma is 0.0001 × 10000 ⁴ , and the emission intensity of tungsten is higher.
As a result, the lamp of the present invention is a lamp that uses light emitted by thermal radiation of the electrode because light emitted from the electrode is larger than light emitted from argon, which is a rare gas sealed in the arc tube.

  Since bromine is sealed in the arc tube 1, even if the electrode 3 becomes hot and tungsten is evaporated, the evaporated tungsten returns to the electrode 3 to prevent the arc tube 1 from being blackened. 1 permeability can be maintained.

  Further, the lamp of the present invention does not emit light by resistance heating in a continuous energization path like a filament of an incandescent lamp, but by discharge between a pair of electrodes 3 in a discontinuous positional relationship through a space. The electrode 3 is heated to emit light. Conventionally, there is no problem specific to an incandescent lamp, such as the filament being disconnected and the current path being cut, and the power input to the lamp is increased to increase the output. In addition, it is possible to achieve a long life.

FIG. 2 is a spectral distribution diagram of light emitted from the lamp of the present invention, which has a continuous spectrum with a large emission intensity on the long wavelength side of wavelength 700 nm or more, and an incandescent lamp having a peak wavelength in the vicinity of 700 nm. It is similar to the spectral distribution of.
This continuous spectrum having a large radiation intensity of 700 nm or more is light emitted from the heated electrode itself when the electrode is heated.

  In the lamp of the present invention, argon is sealed as a rare gas in the discharge space, but this argon does not function as a luminescent material as described above, and is a starting gas for lowering the starting voltage.

A method for investigating whether the emission from the electrode is greater than the emission of the rare gas will be described.
When a lamp that utilizes the discharge phenomenon and uses light emission from the sealed gas or the sealed gas and the sealed metal stops power supply to the lamp, the light emission from the lamp disappears in several hundred microseconds.

On the other hand, the lamp of the present invention heats the electrode itself, and light is emitted from the heated electrode.
In the case of such a lamp, the electrode does not cool immediately after the power supply to the lamp is stopped, and the temperature of the electrode gradually decreases, and light emitted from the electrode gradually decreases.

Using this phenomenon, assuming that the emission intensity during steady lighting is A and the emission intensity after 1 millisecond after stopping the power supply to the lamp is B, the relationship of B / A is B / A> 0. If 5, the light emission from the electrode is determined to be greater than the light emission of the rare gas.
In the case of the lamp shown in FIG. 1, B / A = 0.65, the light emission from the electrode is larger than the light emission of the rare gas, and the electrode using the light emitted from the heated electrode is the light emitting portion. It is a lamp.

Furthermore, a lamp that emits light by thermal radiation has a causal relationship between the surface area of the light emitting portion and the lamp current, and it is necessary to satisfy the following relationship (Equation 1).
The surface area of the electrode is X (mm ² ) and the lamp current is Y (A).
0.05 ≦ Y / X ≦ 5.0 (Formula 1)

When Y / X is less than 0.05, the electrode is not sufficiently heated, and the light emitted from the electrode becomes weak, and a practical lamp cannot be obtained.
On the other hand, if Y / X exceeds 5.0, the temperature of the electrode is excessively increased, and the entire electrode melts instantaneously and does not function as a lamp.
The lamp shown in FIG. 1 of the present invention has a Y / X value of 3.18.

FIG. 3 is a lamp showing another embodiment of the present invention, in which a high melting point member 4 is disposed between a pair of electrodes 3.
The high melting point member 4 has a substantially spherical body with a tip portion 4a having a maximum diameter of 0.5 mm. The tip portion 4a is positioned between the pair of electrodes 3 and is one of the support portions 4b following the tip portion 4a. The portion is embedded in the arc tube 1, and the high melting point member 4 is supported and fixed in the arc tube 1.
The electrode structure other than the high melting point member 4, the arc tube enclosure, the input power amount, and the like are the same as those of the lamp shown in FIG.

  When a voltage is applied between the electrodes 3, the tip portion 4a is also sufficiently heated by the heat generated by the arc and by the current flowing in the tip portion 4a, and the atoms constituting the tip portion thermally vibrate. Energy is emitted as light by thermal radiation, and the tip portion 4a itself becomes a light emitting portion.

  As a result, a plurality of light emitting portions exist in the arc tube 1, and the shape of the light emitting portion can be freely changed by changing the arrangement position and the number of the high melting point members 4, for example, It is possible to obtain a shape of the light emitting part suitable for the application, such as arranging on a straight line, making the light emitting part a polygonal apex, and making the light emitting part flat.

Furthermore, it is preferable that the electrode 3 and the high melting point member 4 are high-purity tungsten of 99.99 wt% or more.
Thus, by using high-purity tungsten for the electrode 3 and the high-melting point member 4, impurities are not released from the electrode and the high-melting point member during lighting, and the halogen cycle can always function reliably and light emission. The blackening of the tube can be reliably suppressed.

  Further, since the electrode 3 has a substantially spherical shape, even when the temperature of the electrode becomes close to the melting point during lighting or the surface of the electrode 3 is melted beyond the melting point, the electrode 3 becomes substantially spherical by its surface tension. Thus, the wear of the electrode 3 can be suppressed, the arc tube 1 can be prevented from being blackened, the variation in the distance between the electrodes can be suppressed, and the variation in the lamp characteristics can be suppressed.

When the electrode separation distance between the electrodes 3 or the separation distance between the electrode 3 and the high melting point member 4 is 1 mm or less, the electric power input to the electrode 3 contributes to the heating of the electrode 3 or the high melting point member 4 at a high rate, The electrode 3 or the high melting point member 4 can be efficiently heated, the electric power supplied to the lamp can be efficiently converted into light, and the lamp efficiency can be increased.
Furthermore, since the electrode separation distance or the separation distance between the electrode 3 and the high melting point member 4 is 1 mm or less, the light emitting portion can be made visually continuous.

  For the sake of convenience, a halogen-resistant protective layer 5 made of a rhenium plating layer having a thickness of 5 μm or more is provided on the surface of the electrode support rod 2, which is a non-light emitting portion indicated by a dotted line in FIG. 3, and the surface of the support portion 4 b of the high melting point member 4. Thus, the non-light emitting portion is not eroded by the halogen enclosed in the arc tube, and the life of the lamp is further promoted.

It is explanatory drawing of the lamp | ramp of this invention. It is explanatory drawing which shows the spectral distribution of the lamp | ramp of this invention. It is explanatory drawing of the lamp | ramp of the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Arc tube 2 Electrode support rod 3 Electrode 4 High melting point member 4a High melting point member tip 4b High melting point member support 5 Halogen resistant protective film

Claims (9)

A lamp in which a pair of electrodes are arranged opposite to each other in an arc tube, and a rare gas and a halogen are enclosed in the arc tube,
The lamp is characterized in that the electrode is heated by discharge to form a light emitting part by heat radiation. The lamp according to claim 1, wherein light emitted from the electrode is larger than light emitted from the rare gas. The lamp according to claim 2, wherein the relationship between the surface area X (mm ² ) of the electrode and the lamp current Y (A) is 0.05 ≦ Y / X ≦ 5.0. The lamp according to any one of claims 1 to 3, wherein a high-melting-point member serving as another light-emitting portion is disposed between the pair of electrodes. The lamp according to any one of claims 1 to 4, wherein the electrode and the high melting point member are tungsten of 99.99 wt% or more. The lamp according to claim 1, wherein the electrode has a substantially spherical shape. The lamp according to claim 1 or 4, wherein a distance between the electrodes or a distance between the electrodes and the high melting point member is 1 mm or less. The lamp according to claim 1 or 4, wherein a halogen-resistant protective layer is formed on a part of the electrode and the high melting point member. The lamp according to any one of claims 1 to 8, wherein the electrode is turned on beyond a melting point.

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