JPH09219290A - Discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp having a long life. SOLUTION: A front face lens 14 is incorpolated to the front opening portion of a vessel-like reflector 10 so as to partitioning form a lamp room S, an discharge bulb 20 equipped with an arc tube emitting light by arc discharge between electrodes 23, 23 is provided in the lamp room S. By providing two arc tubes 21A, 21B which are connected to a feed line in parallel in the discharge bulb 20 and are alternately lighted, the number of discharge and discharge-stop of the respective arc tube 21A, 21B becomes one half of the number of the discharge and the discharge-stop of a discharge lamp provided with one arc tube so that the longer life of the arc tubes 21A, 21B and longer life of this lamp are achieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-intensity discharge lamp using a discharge bulb equipped with an arc tube that emits light by arc discharge between electrodes as a light source, and is particularly applicable to lighting of stores and general houses. It relates to low wattage or less wattage discharge lamps.

[0002]

2. Description of the Related Art As a conventional technique of this kind, as shown in FIG. 8, a front lens b is engaged and integrated with a front opening of a glass reflector a having a paraboloid of revolution a _1. A lamp chamber S is defined, and an arc tube c, which is a light source main body, is disposed in the lamp chamber S by fixing its rear end portion to the rear top portion of the reflector a.

[0003] arc tube in the closed glass bulb c ₁ of c, the electrode d, e are oppositely arranged, from both ends of the arc tube c, the electrode d, lead f to conduct e, g is derived It is connected to power supply lines h and i.

[0004]

In this type of lamp, since the arc tube c which is the light source main body is less likely to be broken than the filament type light source main body of the incandescent light bulb, the lamp has a long life and emits light against power consumption. Due to its large volume and high efficiency, it is now widely used in large-scale facilities such as stadiums, roads and gymnasiums. It is expected that it will be widely used in stores and general houses in the future, but once this type of lamp is turned off, it takes a few minutes to turn it on again (the lamp must be cooled to a specified temperature). ) Has the drawback. Therefore, in large-scale facilities, there is no danger of repeating lighting and extinguishing frequently, but in lighting for stores and general homes where it is inevitable to repeat lighting and extinguishing, this relighting takes too much time. This was one of the reasons why the points could not spread.

Therefore, recently, by improving the starter circuit, a discharge lamp which is turned on immediately after being turned off has been proposed. However, in a high-intensity discharge lamp, in general, when the arc tube is turned on and off frequently, there is a problem that the life of the arc tube is shortened as shown in FIG. Note that FIG. 9 is a diagram showing the relationship between the number of blinks of the arc tube (the number of discharges per hour) and the life.

When the inventor investigated the starting voltage required to turn on the discharge lamp (discharge the arc tube again) after turning off the discharge lamp (stop discharging the arc tube), the data shown in FIG. was gotten.
That is, once the arc tube stops discharging, the starting voltage required for re-discharging is gradually increased until about 20 seconds after the discharge is stopped, and gradually decreased after 20 seconds, about 300 seconds ( Normal starting voltage (13 to 1)
4KV) was confirmed. Therefore, when two arc tubes having the same structure and the same starting voltage are connected in parallel to the power supply circuit to the arc tube, even if two arc tubes with the same specifications have a small starting voltage. Due to this difference, only one of the two arc tubes having a slightly lower starting voltage is discharged. Then, after the discharge of the arc tube is stabilized, when the power supply to the power supply path is stopped, the discharge of the arc tube is stopped, and when the power is supplied to the power supply path again, only the arc tube that has not been discharged first starts discharge. . This is because the starting voltage of the arc tube immediately after the discharge was stopped (5
For a period of time), the voltage is higher than the starting voltage of the other arc tube (arc tube that did not discharge), and when power is supplied to the power supply line again, the other starting voltage of the other arc tube is low. This is because the arc tube starts discharging.

As described above, according to the present invention, in the case where "two arc tubes are connected in parallel to a power feeding path and the power feeding to the power feeding path and the stop of the power feeding are repeated, the arc tube and other It was made possible under the knowledge of the inventor that the arc tubes can be alternately discharged because of the difference in the starting voltage of the arc tubes. The purpose of the present invention is to provide a discharge lamp in which the life of each arc tube is extended and the life of the arc lamp can be extended by alternately discharging.

[0008]

To achieve the above object, in a discharge lamp according to claim 1, a front lens is attached to a front opening of a container-shaped reflector to define a lamp chamber, and an electrode is provided. In a discharge lamp having a discharge bulb provided with an arc tube that emits light by an arc discharge between the two discharge lamps, the discharge bulb is connected in parallel to a power supply path and alternately lit. Is provided. In the discharge lamp according to claim 2, a front lens is attached to a front opening of a container-shaped reflector to define a lamp chamber, and a discharge bulb equipped with an arc tube that emits light by arc discharge between electrodes is provided in the lamp. In a discharge lamp provided as a light source in a room, the discharge bulb is provided with two arc tubes that are connected in parallel to a power supply line and alternately light, and the arc is formed in the power supply line by linking with a discharge lamp lighting switch. A power supply switching means for alternately switching power supply to the tube is provided. According to a third aspect of the present invention, in the discharge lamp according to the first or second aspect, the discharge bulb is fixedly integrated with a bulb insertion hole formed at a rear top portion of the reflector via an adhesive. In claim 4, claim 1
Or in the discharge lamp according to 2, the discharge bulb is
It is configured to be detachably provided in a valve insertion hole formed at the rear top portion of the reflector. Next, the operation of the present invention will be described. When power is supplied to the power supply paths to the arc tubes connected in parallel, the first arc tube having a slightly lower starting voltage starts discharging. When the power supply is stopped after the discharge is stabilized, the first arc tube stops the discharge, but the starting voltage of the first arc tube is higher than the starting voltage of the second arc tube. In the meantime, when power is supplied to the power supply path to the arc tube again, the starting voltage of the second arc is lower than that of the first arc tube.
The arc tube starts to discharge. When the power supply is stopped after the discharge is stabilized, the discharge of the second arc tube is stopped, but the starting voltage of the second arc tube is higher than the starting voltage of the first arc tube. In the meantime, when power is again supplied to the power supply path to the arc tube, the first arc tube whose starting voltage is lower than that of the second arc tube starts discharging. in this way,
When power feeding and power feeding stop are repeated in the power feeding path to the arc tube, two arc tubes are alternately discharged, and the number of discharges (discharging stop) in each arc tube is
The number of arc tube discharges (discharge stop) is half that of a single discharge lamp. In claim 1, the arc tubes are alternately discharged only when power is supplied within a predetermined time after the discharge of one arc tube is stopped and the starting voltages of the two arc tubes are different from each other. According to the second aspect of the present invention, since the power supply switching means is linked to the discharge lamp lighting switch to switch the power supply to the plurality of arc tubes alternately or sequentially, the arc tubes are always discharged alternately or sequentially. In the third aspect, the discharge bulb is fixed to the reflector and unitized as a discharge lamp, which is easy to handle. According to the fourth aspect, the discharge bulb can be replaced by removing the discharge bulb from the reflector.

[0009]

Next, embodiments of the present invention will be described based on examples. 1 and 2 show the first embodiment of the present invention.
FIG. 1 shows a PAR type discharge lamp that is convenient for in-store lighting, etc., and FIG. 1 is a vertical sectional view of the PAR type discharge lamp.
FIG. 2 is a circuit configuration diagram of a power supply circuit to the arc tube.

In these drawings, reference numeral 10 is a glass-made substantially bowl-shaped reflector having an opening on the front surface, on the inner surface of which a rotary parabolic reflection surface 12 is formed by aluminum vapor deposition. The glass front lens 14 is assembled and integrated in the front opening of the lamp chamber S to define the lamp chamber S. In the lamp chamber S, the electrodes 23 in the sealed glass bulb 22 are formed.
Arc tube 21 that emits light by arc discharge between 23
A discharge bulb 20 having A and 21B is provided.
An adhesive is interposed in the joint between the front lens 14 and the reflector 10, and the engaging portion between the two 14 and 10 is fixed and sealed.

A bulb insertion hole 11 is formed at the rear top of the reflector 10, and a discharge bulb 20 is attached and fixed to the bulb insertion hole 11 so that the arc tube 21A,
21B extends forward in the lamp chamber S, and the respective sealed glass balls 22, 22 are located at predetermined positions near the focal point of the reflecting surface 12. The discharge bulb 20 has a structure in which a pair of arc tubes 21A and 21B extend in parallel in front of the insulating base 30. Each arc tube 21A,
21B is a hermetically sealed glass bulb 2 in which electrodes 23, 23 are provided opposite to each other.
2, the pinch seal portions 24, 24 are formed so as to face each other, and the lead wires 25, 26 leading to the electrodes 23, 23 are led out from the pinch seal portions 24, 24, respectively. The discharge bulb 20 is integrated with the base 30 by inserting and fixing the cylindrical extending portions 27, 27 integrally formed on the rear end side of 21B into the insulating base 30.

The insulating base 30 supporting the arc tubes 21A and 21B has a screw (not shown) having a synthetic resin plug 41 having an arc tube insertion hole 42 formed on the back surface of the ceramic disk 31 having the arc tube insertion hole 32 formed therein. L-shaped in which the front end side lead wire 25 of the arc tube is connected to the continuous lead support insertion holes 33 and 43 provided in the base 30 (disk 31, plug 41). The lead support 34 is fixed through.

Reference numeral 35 denotes a ceramic tube externally fitted to the lead support 34, which is fixed to the ceramic disk 31 by an inorganic adhesive loaded in the hole 33. Reference numeral 38 is an inorganic adhesive loaded in the arc tube insertion hole 32 of the ceramic disk 31, and is for fixing the arc tubes 21A and 21B to the ceramic disk 31.

On the front surface of the ceramic disk 31,
An annular groove 36 with which the rear top of the reflector 10 can be engaged
An inorganic adhesive 37 is loaded between the concave groove 36 and the rear top of the reflector 10, and the ceramic disk 31 is fixedly integrated with the valve insertion hole 11, that is, the valve 20 is fixedly integrated with the reflector 10. Has been converted. Further, at the rear end portion of the synthetic resin plug 41, the power supply side connector 5
A valve-side connector 45 that can be connected to 0 is provided. That is, on the bottom surface of the rear end side recess 47 surrounded by the peripheral wall 46 of the synthetic resin plug 41, the arc tubes 21A, 21
One metal high-voltage side terminal 48 to which the rear end side lead wires 26, 26 extending from B are connected is provided, and the arc tube 21A, 21B is provided on the outer peripheral surface of the base portion of the peripheral wall 46 surrounding the high-voltage side terminal 48. A metal belt-shaped low-voltage side terminal 49 connected to a lead support 34 which is electrically connected to the front end side lead wires 25 of the valve side connector 4 is provided.
5 are configured.

In the arc tubes 21A and 21B of the discharge bulb 20 thus constructed, a starter circuit for applying a high voltage between the electrodes of the arc tube to instantly start discharge and between the electrodes of the arc tube. Power is supplied through a power cord 52 and a power supply side connector 50 extending from a starter / ballast circuit unit integrally accommodating a ballast circuit for continuously performing stable arc discharge, and the battery B and the starter / ballast circuit unit are supplied. By turning on / off a power supply switch SW which is a discharge lamp lighting switch provided in a power supply path between 60, power supply to the discharge bulb (arc tubes 21A, 21B) and power supply stop are performed. .

The two arc tubes 21A and 21B are
It is connected in parallel to the power supply path, and when the power supply switch SW is turned on, power is supplied to the power supply path of the arc tube and the arc tube 21A having a low starting voltage is lit. The two arc tubes 21A and 21B are manufactured to have the same starting voltage by design, but the starting voltages are not exactly the same and are slightly different due to variations. Then, only the arc tube 21A having a slightly lower starting voltage is discharged and the lamp is lit.

After the discharge becomes stable after about 5 minutes or more,
When the power supply switch SW is turned off, the power supply to the power supply path of the arc tube is stopped, the discharge of the arc tube 21A that has been discharged until now is stopped, and the lamp is turned off. After that, while the start voltage of the two arc tubes 21A and 21B is different, if the power supply switch SW is turned on again within, for example, 5 minutes, power is supplied to the power supply path of the arc tube and immediately after the discharge is stopped. Another arc tube 21B that is not the arc tube 21A with a high starting voltage
Discharges and the lamp lights up. That is, for a while after the lamp is extinguished, the starting voltage of the other arc tube 21B is naturally lower than the starting voltage of the arc tube 21A immediately after the discharge is stopped, and only the arc tube 21B having this low starting voltage is discharged. .

After that, when the power supply switch SW is turned off after the discharge of the arc tube 21B is stabilized, the power supply to the power supply path of the arc tube is stopped and the arc tube 2
The discharge of 1B stops and the lamp goes out. After turning off the lamp, if the power supply switch SW is turned on again while the starting voltage of the arc tubes 21A and 21B is different,
The arc tube 21A that has not been discharged immediately before is discharged and the lamp is turned on. In this way, the arc tubes can be alternately discharged within a predetermined time after the discharge lamp is turned off.

The front lens 14 is made of hard glass capable of cutting off the ultraviolet rays in the wavelength range harmful to the human body generated by the light emission of the arc tubes 21A and 21B, and the light emitted from the hermetically sealed glass bulb 22 passes through the front lens 14. Ultraviolet rays in the harmful wavelength range are removed by transmission. In addition, the back surface of the front lens 14 is subjected to a texture treatment by sandblasting or a chemical treatment, and the light emitted from the front lens 14 is diffused and smoothed, whereby the light distribution difference due to the alternating discharge of the arc tube is caused. There are few structures.

3 to 5 show a PAR type discharge lamp according to a second embodiment of the present invention. FIG. 3 is a vertical sectional view of the PAR type discharge lamp, and FIG. 4 is power supply to an arc tube. FIG. 5 is a circuit configuration diagram of a circuit, and FIG. 5 is a diagram showing a time chart of discharge of an arc tube and blinking of a discharge lamp due to stop of discharge. In these figures, the arc tube 21A, 2A is provided at the rear end of the synthetic resin plug 41 of the discharge bulb 20A.
1B is provided with a pair of high-voltage side terminals 48a, 48b to which rear-end side lead wires 26, 26 are respectively connected, and cooperates with the low-voltage side terminal 49 to form a valve-side connector 45.
A is configured, and a high-voltage side power supply path between the starter / ballast circuit unit 60 and the two arc tubes 21A, 21B is connected to the ON / OFF switching operation of the power supply switch SW to switch the power supply path. A relay 62 is provided.

That is, in the power feeding path between the power feeding switch SW and the starter / ballast circuit unit 60, the voltage drop when the power feeding switch SW is turned off is detected,
A control circuit 64 such as a relay sequence or a microcomputer for controlling ON / OFF of the switches Sw ₁ and Sw ₂ of the high voltage relay 62 is provided. FIG. 5 shows a power supply switch S.
When the W is turned on and off, two arc tubes 21A, 2
The time chart which 1B discharges by turns is shown. First, the power supply switch SW is opened (OFF), the relay switch Sw ₁ is closed (ON), and the relay switch Sw is
When the power supply switch SW is closed (ON) when the lamp is turned off when ₂ is open (OFF) (at time t ₁ ),
Power is supplied to the power supply path of the arc tube and the first arc tube 21A is discharged, so that the lamp is turned on.

Thereafter, when the power supply switch SW is opened (OFF) at time t ₂ , the control circuit 64 detects this and is provided in the power supply paths of the first and second arc tubes via the high voltage relay 62. Relay switch Sw ₁ , S
Output w ₂ to open and close. Thereby, the first
The relay switch Sw ₁ provided in the power supply path of the arc tube 21A is opened (OFF), and the relay switch Sw ₂ provided in the power supply path to the second arc tube 21B is closed (ON). However, since the power feeding switch SW is opened (OFF) and power is not being fed to the power feeding path of the arc tube, the second actuating tube 21B is not discharged and the lamp remains off.

Next, when the power supply switch SW is closed (ON) at time t ₃ , power is supplied to the power supply path of the second arc tube 21B, the second arc tube 21B is discharged, and the lamp is discharged. Lights up. After that, when the power supply switch SW is opened (OFF) at time t ₄ , the control circuit 64
Detects this, closes (ON) the relay switch Sw ₁ through the high-voltage relay 62, and relay switch Sw ₂
Open (OFF). However, since the power supply to the power supply path of the arc tube is stopped, the second arc tube 2
The discharge of 1B stops and the lamp goes out.

After that, when the power supply switch SW is closed (ON) at time t ₅ , the relay switch Sw ₁ is in the closed (ON) state, so that the first arc tube 21A supplied with power is discharged, The lamp lights up. Then t ₆
At this point, when the power supply switch SW is opened (OFF),
The control circuit 64 detects this, the relay switch Sw ₁ to open (OFF) via a high-pressure relay 62, a relay switch Sw ₂ is closed (ON). However, since the power supply switch SW is opened (OFF) and power is not being supplied to the power supply path of the arc tube, the arc tube 21B is not discharged and the lamp remains off.

After that, when the power supply switch SW is closed (ON) at time t ₇ , power is supplied to the power supply path of the arc tube and the relay switch Sw ₂ is in the closed (ON) state. 21B is discharged and the lamp is turned on. Thereafter, when the power supply switch SW at t ₈ point is opened (OFF), which was detected by the control circuit 64, a high pressure relay 62 is actuated, the relay switch Sw ₁ closed (ON), and the relay switch Opened Sw ₂ (OF
F). However, the power supply switch SW is opened (OFF)
The arc tube 21A is not discharged because the power is not supplied to the power supply path of the arc tube and the lamp remains off.

As described above, in the discharge lamp of this embodiment, the arc tube 21 is turned on and off by turning on and off the power supply switch SW.
Since A and 21B are alternately lit to light up, the number of times each arc tube 21A and 21B is discharged and stopped is naturally halved compared to the case where there is only one arc tube. As a result, the life of each arc tube is extended (see FIG. 9), and the life of the discharge lamp is extended.

6 and 7 show a PAR type discharge lamp according to a third embodiment of the present invention. FIG. 6 is a longitudinal sectional view of the lamp and FIG. 7 is a perspective view showing a means for attaching and detaching a discharge bulb. It is a figure. In the two embodiments described above, the discharge bulb 20
(20A) was adhered and fixed to the valve insertion hole 11 of the reflector 10 so that it could not be removed.
In the present embodiment, a holder receiver 70 is integrally formed by surrounding and bending the rear end of the reflector so as to surround the valve insertion hole 11.
Cylindrical fixed holder 8 having J-slot 82 capable of engaging with engagement protrusion 72 formed on holder holder 70.
The reflector 1 is provided by a fixing means composed of 0 and
The discharge bulb 20B can be attached to and detached from zero.

That is, the holder receiver 70 is formed in a short cylindrical shape by a metal plate, and is fixedly integrated with the reflector 10 by being externally fitted to the rear top portion of the reflector 10 and adhesively fixed. On the other hand, a J slot 82 is formed on the outer surface of the fixed holder 80 having an opening 81 through which the synthetic resin plug 41 can be inserted.
Engages with the engaging projection 72 on the holder receiving 70 side, and the compression coil spring 84 housed in the fixed holder 80 presses and holds the ceramic disk 31 on the peripheral edge of the valve insertion hole 11, thereby allowing the valve 20B. Is fixed to the valve insertion hole 11.

For this reason, the discharge bulb 20 is so arranged that the ceramic disk 31 is brought into contact with the peripheral portion of the bulb insertion hole 11.
By disposing B, aligning the engaging protrusion 72 of the holder receiver 70 with the J slot 82 of the fixed holder 80, and rotating the fixed holder 80, the discharge bulb 20B can be easily replaced by the bulb of the reflector 10. It can be fixed in the insertion hole 11 and can be easily removed.

On the front surface of the ceramic disc 31,
The base end portion of the cylindrical ultraviolet shielding globe 90 is fixed by an inorganic adhesive, and the ultraviolet shielding globe 90 surrounds the arc tubes 21A and 21B. For this reason, among the light emitted from the arc tubes 21A and 21B, the ultraviolet rays in the wavelength range harmful to the human body are generated by the glove 90.
Is cut when passing through the front lens 14 made of hard glass, and is cut when passing through the front lens 14 made of hard glass, so that only light in a wavelength range harmless to the human body is emitted from the discharge lamp.

The inner surface and / or outer surface of the globe 90 is subjected to a texture treatment so that the transmitted light of the globe 90 is diffused. The structure is such that the difference in the light distribution of the lamp due to the switching of the arc tube is extremely small. The ultraviolet ray shielding globe 90 may be a cap type in which the front end portion is closed, instead of the cylindrical type in which the front end portion is open.

In the above-mentioned two embodiments, the front lens 14 is fixed to the front opening of the reflector 10 with an adhesive, but in this embodiment, the reflector 1
A ring-shaped rubber packing 17 is attached to the outer periphery of the engaging portion between the peripheral edge of the front opening of 0 and the peripheral edge of the front lens 14, and the metal band 16 is wound around the outer side of the packing 17. The front lens 14 is fixedly integrated with the reflector 10.

The other structure of this embodiment is the same as that of the second embodiment, and the description thereof will be omitted by giving the same reference numerals. The discharge bulbs 20A and 20B in the second and third embodiments described above are provided with two arc tubes 21A and 21B, respectively, and the power supply switching means alternately supplies power to the arc tubes 21A and 21B. However, it is also possible to provide three or more arc tubes and sequentially switch the power supply to the arc tubes by the power supply switching means so that the arc tubes are discharged in order.

[0034]

As is clear from the above description, according to the discharge lamp of the first aspect, since the two arc tubes are alternately discharged, the number of times of discharge of one arc tube and stop of discharge is As a result, the life of each arc tube is extended by half the number of times of arc tube discharge and discharge stoppage in a conventional discharge lamp having one arc tube, which in turn guarantees a long-term use of the discharge lamp.
According to claim 2, when there are two arc tubes,
When the arc tubes are surely discharged alternately and the number of arc tubes is 3 or more, the arc tubes are surely discharged in order, so the number of times each arc tube is discharged and stopped is reduced, and each arc tube is discharged. The life of the tube is extended,
As a result, long-term use of the discharge lamp is guaranteed. According to claim 3, since the discharge lamp is unitized as a reflector with a discharge bulb,
Convenient handling of the discharge lamp. According to claim 4,
Replacing only the discharge bulb guarantees a long-term use of the discharge lamp.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a PAR type discharge lamp according to a first embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a power supply circuit for the arc tube.

FIG. 3 is a vertical sectional view of a PAR type discharge lamp according to a second embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a power supply circuit for the arc tube.

FIG. 5 is a diagram showing a time chart of arc tube discharge and discharge stop.

FIG. 6 is a vertical sectional view of a PAR type discharge lamp according to a third embodiment of the present invention.

FIG. 7 is a perspective view showing a discharge bulb attaching / detaching means.

FIG. 8 is a vertical sectional view of a conventional discharge lamp.

FIG. 9 is a diagram showing the relationship between the number of discharges (discharge stop) and the life of the arc tube.

FIG. 10 is a diagram showing a change characteristic of the starting voltage of the arc tube after the discharge is stopped.

[Explanation of symbols]

10 reflector 11 bulb insertion hole 14 front lens 20, 20A, 20B discharge bulb 21A, 21B arc tube 23 electrode 30 insulating base 45, 45A valve side connector 50 power supply side connector 60 starter / ballast circuit unit 62 power supply switching means High-voltage relay 64 Control circuit that is power supply switching means 70 Holder receiver that constitutes discharge valve fixing means 80 Fixed holder that constitutes discharge valve fixing means SW Switch for supplying power to arc tube that is a discharge lamp lighting switch Sw ₁ , Sw ₂ relay Switch S light room

Claims (4)

[Claims] 1. A discharge bulb provided with an arc tube, in which a front lens is attached to a front opening of a container-shaped reflector to define a lamp chamber, and which emits light by arc discharge between electrodes, is provided as a light source in the lamp chamber. In the discharge lamp described above, the discharge bulb is provided with two arc tubes that are connected in parallel to a power supply path and are alternately turned on. 2. A discharge bulb equipped with a front lens is defined in a front opening of a container-shaped reflector to define a lamp chamber, and a discharge bulb having an arc tube for emitting light by arc discharge between electrodes is provided as a light source in the lamp chamber. In this discharge lamp, the discharge bulb is provided with a plurality of arc tubes connected in parallel to a power supply path, and the power supply path alternately supplies power to the arc tubes in association with a discharge lamp lighting switch. A discharge lamp comprising a power supply switching means for switching. 3. The discharge lamp according to claim 1, wherein the discharge bulb is fixedly integrated with a bulb insertion hole formed at a rear top portion of the reflector via an adhesive. 4. The discharge lamp according to claim 1, wherein the discharge bulb is detachably provided in a bulb insertion hole formed in a rear top portion of the reflector.