JP2016100227A - Ceramic metal halide lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for preventing an outer tube from thermally deforming due to high temperature in a high-watt type ceramic metal halide lamp including a cylindrical outer tube.SOLUTION: A ceramic metal halide lamp 100 comprises a discharge container 130 for housing a light-emitting material, and a translucent outer tube 111 for housing the discharge container 130. A sleeve 108 is provided between the discharge container 130 and the outer tube 111. When rated lamp power is P[W], the inner surface radius of the outer tube 111 is R[mm], the distance between an outer surface of the discharge container 130 and an inner surface of the sleeve 108 is t[mm], and the distance between an outer surface of the sleeve 108 and an inner surface of the outer tube 111 is t[mm], the following relational expression is established: (R/P)≤0.06[mm/W],1.0≤(t/t)≤2.0.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to a ceramic metal halide lamp, and more particularly to a high watt type ceramic metal halide lamp having a substantially cylindrical outer tube.

  In recent years, ceramic metal halide lamps using a ceramic discharge vessel have become widespread. A ceramic metal halide lamp typically has a ceramic discharge vessel (light-emitting tube) and a translucent outer tube for housing it. The shape of the outer tube includes a B shape (barrel shape), a G shape (spherical shape), a T shape (cylindrical shape), an R shape (reflection shape), a BT shape (a combined shape of B shape and T shape), and the like. The lighting direction includes a BH type (horizontal lighting type), a BU type (vertical lighting type), and the like. The BH type refers to a lamp installed so that the center axis of the lamp is substantially horizontal, but in reality, the lamp is installed with the center axis of the lamp inclined at an angle of 0 to 75 degrees with respect to the horizontal. May be. The BU type is one that is installed such that the base is on the upper side and the central axis of the lamp is substantially vertical.

  In general, a ceramic metal halide lamp is often used as a vertical lighting type in a high ceiling lighting device such as a factory or a gymnasium, and a horizontal lighting type is often used as an illumination for an outdoor signboard. Here, the high wattage type means a lamp having a rated lamp power of 450 W or more, particularly 500 to 1000 W.

Japanese Patent Laid-Open No. 2014-63623 WO2006 / 001166 (Patent No. 4129279)

  Outer tubes such as B-type, G-type, and BT-type are swollen around the discharge vessel, and the outer diameter is large. Therefore, the distance between the discharge vessel and the outer tube can be made relatively large. However, in a cylindrical outer tube such as the T shape, the discharge vessel and the outer tube approach each other, and the temperature of the outer tube increases. In particular, in a high watt type horizontally lit lamp, the temperature of the outer tube is locally high near the discharge vessel and may be thermally deformed.

  An object of the present invention is to provide a technique for preventing an outer tube from being thermally deformed at a high temperature in a high watt type ceramic metal halide lamp having a cylindrical outer tube.

  The inventor of the present application diligently studied a means for avoiding the outer tube from becoming high temperature in a high watt type horizontally lit ceramic metal halide lamp having a cylindrical outer tube. In order to prevent the outer tube from becoming hot, the distance between the outer tube and the discharge vessel may be increased. However, when the outer tube is cylindrical, the distance between the outer tube and the discharge vessel cannot be increased. Therefore, the inventor of the present application has conceived of providing a sleeve between the outer tube and the discharge vessel. In the BT type outer tube, it is known that the discharge vessel is covered with a sleeve in order to prevent destruction of the outer tube due to the rupture of the discharge vessel. However, in a high watt type ceramic metal halide lamp provided with a cylindrical outer tube, there is no known example in which a sleeve is provided to prevent the outer tube from becoming hot.

  Therefore, the inventor of the present application has conducted a number of experiments and confirmed that the temperature of the outer tube can be prevented by providing a sleeve between the outer tube and the discharge vessel.

According to an embodiment of the present invention, in a ceramic metal halide lamp having a discharge vessel containing a luminescent material and a translucent outer tube containing the discharge vessel,
A sleeve is provided between the discharge vessel and the outer tube, the rated lamp power is P [W], the inner surface radius of the outer tube is R ₃ [mm], and the distance between the outer surface of the discharge vessel and the inner surface of the sleeve Is t ₁ [mm], and the distance between the outer surface of the sleeve and the inner surface of the outer tube is t ₂ [mm], the following relational expression may be satisfied.
(R ₃ /P)≦0.06 [mm / W]
1.0 ≦ (t ₂ / t ₁ ) ≦ 2.0

According to an embodiment of the present invention, the following relational expression may be further satisfied in the ceramic metal halide lamp.
(T ₁ + t ₂ ) /P≦0.037 [mm / W]

  According to an embodiment of the present invention, in the ceramic metal halide lamp according to claim 1, the rated lamp power P may be 500 W or more and a horizontal lighting type.

  According to an embodiment of the present invention, in the ceramic metal halide lamp, an inert gas may be enclosed in the outer tube.

According to an embodiment of the present invention, the following relational expression may be further satisfied in the ceramic metal halide lamp.
t ₁ /P>0.01 [mm / W]

  According to an embodiment of the present invention, in the ceramic metal halide lamp, the sleeve may be made of quartz glass.

  ADVANTAGE OF THE INVENTION According to this invention, in the high watt type ceramic metal halide lamp provided with the cylindrical outer tube | pipe, the technique which prevents that an outer tube | pipe becomes high temperature and thermally deforms can be provided.

FIG. 1A is a diagram illustrating a configuration example of a ceramic metal halide lamp according to the present embodiment. FIG. 1B is a diagram illustrating a configuration example of a ceramic metal halide lamp according to the present embodiment. FIG. 2A is a diagram illustrating a configuration example of a discharge vessel of a ceramic metal halide lamp according to the present embodiment. FIG. 2B is a diagram illustrating dimensions of a configuration example of the discharge vessel of the ceramic metal halide lamp according to the present embodiment. FIG. 2C is a diagram illustrating dimensions of a configuration example of the outer tube, the sleeve, and the discharge vessel of the ceramic metal halide lamp according to the present embodiment. FIG. 3A is a diagram illustrating an example of the shape of a T-shaped lamp. FIG. 3B is a diagram illustrating an example of the shape of a B-shaped lamp. FIG. 3C is a diagram illustrating an example of the shape of a BT lamp. FIG. 4A is a graph showing the relationship between the rated lamp power P, the ratio R ₃ / P of the rated lamp power P, the rated lamp power P, the inner radius R ₃ of the outer tube 111, and the rated lamp power P. FIG. 4B is a graph showing the relationship between the ratio R ₃ / P and the maximum temperature of the outer tube surface, which was obtained by an experiment conducted by the inventors of the present application. FIG. 5A is a graph showing the relationship between the rated lamp power P and the ratio (t ₁ + t ₂ ) / P obtained by an experiment conducted by the inventors of the present application. FIG. 5B is a graph showing the relationship between the ratio (t ₁ + t ₂ ) / P and the maximum temperature on the surface of the outer tube, obtained by experiments conducted by the inventors of the present application. FIG. 6 is a graph showing the relationship between the ratio t ₂ / t ₁ and the maximum temperature of the surface of the outer tube, obtained by an experiment conducted by the inventors of the present application.

  Hereinafter, embodiments of a ceramic metal halide lamp according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  1A and 1B are diagrams illustrating the structure of a high watt type horizontal lighting type (BH type) ceramic metal halide lamp according to the present embodiment. 1A and 1B respectively show the configurations of a ceramic metal halide lamp viewed from two directions orthogonal to the center axis of the lamp and orthogonal to each other. The high wattage type means that the rated lamp power is 450 W or more, particularly 500 to 1000 W, typically about 600 to 700 W. The horizontal lighting type (BH type) refers to a lamp installed so that the center axis of the lamp is substantially horizontal, but in reality, the center axis of the lamp is at an angle of about 0 to 75 degrees with respect to the horizontal. May be inclined.

  The ceramic metal halide lamp 100 includes a translucent outer tube (outer sphere) 111, a ceramic discharge vessel (light emitting tube) 130 disposed therein, and a cylindrical shape provided to cover the discharge vessel 130. It has a translucent sleeve 108 (FIG. 1A). The outer tube 111 has a cylindrical container-shaped top portion 111b, a cylindrical portion 111a, and a neck portion 111c. The outer diameter of the cylindrical portion 111a is substantially constant. The outer diameter of the cylindrical part 111a is larger than the outer diameters of the top part 111b and the neck part 111c. Accordingly, small inclined portions are formed at the boundaries between the cylindrical portion 111a, the top portion 111b, and the neck portion 111c. The outer tube 111 of this embodiment is cylindrical, but is particularly called a TT type. The axial dimension of the cylindrical portion 111 a is sufficiently larger than the axial dimension of the discharge vessel 130 and the sleeve 108.

  A sealing portion (not shown) is formed on the neck portion 111c. A screw-in E-shaped base 112 is mounted so as to cover the sealing portion. The base 112 is joined using a heat-resistant adhesive, or screwed into a spiral thread groove formed by a mold. The flared portion of the stem tube 115 in which a pair of lead-in wires are hermetically sealed is sealed in the sealing portion of the neck portion 111c.

  The stem tube 115 supports a support column 109 made of a metal wire shaped into an inverted U shape. A pair of mount support plates 114 </ b> A and 114 </ b> B are attached to the support column 109. One mount support plate 114 </ b> A is disposed on the top portion 111 b of the outer tube 111, and the other mount support plate 114 </ b> B is disposed on the neck portion 111 c of the outer tube 111. The support column 109 supports the discharge vessel 130 at a predetermined position and simultaneously has a power feeding function for supplying power to the discharge vessel 130.

  The ceramic metal halide lamp 100 further includes a getter 113 and a starter 110. In this embodiment, the getter 113 is mounted on the support column 109 on the top side of the discharge vessel 130 and the starter 110 is mounted on the neck side of the discharge vessel 130, respectively. Note that a wire may be spirally wound around the sleeve 108 in order to prevent the outer tube 111 from being damaged when the discharge vessel 130 is ruptured.

The outer tube 111 is made of translucent hard glass such as borosilicate glass, for example. The sleeve 108 is made of translucent quartz glass. The outer tube 111 may be evacuated or may be filled with an inert gas such as argon (Ar) or nitrogen (N ₂ ). Vacuuming the inside of the outer tube 111 is advantageous for maintaining the temperature of the discharge vessel 130 at a high temperature. By maintaining the temperature of the discharge vessel 130 at a high temperature, the lamp efficiency (light emission efficiency) is increased, and evaporation of the luminescent material having a relatively low vapor pressure enclosed in the discharge vessel 130 can be promoted.

  In the ceramic metal halide lamp 100, a base 112 is mounted on a socket (not shown), and electricity is supplied from a power source through a predetermined lighting circuit device (not shown), thereby discharging between the electrodes in the discharge vessel 130. Is generated. As a result, stable lighting is maintained.

  The structure of the discharge vessel 130 will be described with reference to FIG. 2A. The discharge vessel 130 has a central light emitting portion 130C and narrow tube portions (capillary portions) 130A and 130B on both sides thereof. The discharge vessel 130 of this example is a so-called integrated type in which a light-emitting portion 130C having a substantially spheroid shape and thin tube portions 130A and 130B on both sides thereof are integrally formed. However, the discharge vessel 130 may be formed by connecting separately manufactured narrow tube portions 130A and 130B on both sides of the light emitting portion 130C.

  Electrode systems 120a and 120b are mounted on the thin tube portions 130A and 130B, respectively. The electrode systems 120 a and 120 b include a tungsten electrode 123, a current supply conductor 122, and a lead wire 121. A tungsten coil is attached to the tip of the tungsten electrode 123. The tip of the tungsten electrode 123 is disposed in the light emitting part 130 </ b> C of the discharge vessel 130.

  The current supply conductor 122 includes a halogen-resistant intermediate material 122a and a conductive cermet rod 122b. The tungsten electrode 123, the current supply conductor 122, and the lead wire 121 are connected by butt welding.

  In addition to the inert gas and mercury, an additive that is a luminescent material is enclosed in the light emitting unit 130C of the discharge vessel 130. The amount of mercury added is a maximum of 100 mg, preferably about 85 mg. Additives include alkali metal halides, alkaline earth metal halides, rare earth metal halides, etc. The total amount of these additives is up to 20 mg. The inert gas is, for example, a rare gas, but is argon in this embodiment.

  When the ceramic metal halide lamp is turned on, the mercury and the additive are heated in the light emitting portion 130C, a part of which evaporates and is excited by the discharge to emit light. The remaining part is pooled in a liquid phase state at the bottom of the light emitting unit 130C. A part of the liquid phase evaporates, circulates inside the light emitting unit 130C by convection, and returns to the bottom. Such a cycle is repeated while the lamp is on.

  The dimensions of the discharge vessel 130 and the sleeve 108 of the ceramic metal halide lamp according to the present embodiment will be described with reference to FIG. 2B. The dimension of the discharge vessel 130 in the axial direction is L1, the outer diameter of the light emitting part 130C is D1, and the effective inner diameter of the light emitting part 130C is D. The outer diameter dimension D1 is the maximum outer diameter of the light emitting unit 130C, that is, the outer diameter dimension at the center of the light emitting unit 130C. The effective inner diameter D is the maximum inner diameter of the light emitting unit 130C, that is, the inner diameter dimension at the center of the light emitting unit 130C. The outer diameter of the sleeve 108 is D2, and the axial dimension of the sleeve 108 is L2. The dimension L2 is at least larger than the dimension in the axial direction of the light emitting unit 130C.

  The arc length AL is defined by the distance between the two electrodes 123. That is, the arc length AL is a distance between the tips of the two electrodes 123 in the light emitting unit 130C. The ratio AL / D between the arc length AL of the discharge vessel and the effective inner diameter D is referred to as a shape parameter of the discharge vessel 130. When the light emitting unit 130C is an elongated type, the value of the shape parameter AL / D is large, and when the light emitting unit 130C is a short thick type, the value of the shape parameter AL / D is small.

  The electrode protrusion length L is defined by the length of the electrode 123 protruding into the light emitting unit 130C. That is, the electrode protrusion length L is the distance between the outer end of the transition curved surface Ls formed at the boundary between the light emitting portion 130C and the thin tube portions 130A and 130B and the tip of the electrode 123. When the light emitting unit 130C is cylindrical, the electrode protrusion length L is the distance between the end surface of the light emitting unit 130C and the tip of the electrode 123. The ratio L / D between the electrode protrusion length L and the effective inner diameter D is referred to as an electrode parameter. A wall load is used as a performance parameter of the discharge vessel 130. Here, the wall surface load is defined by a value obtained by dividing the rated lamp power by the total inner area of the light emitting unit 130C.

In the horizontal lighting type ceramic metal halide lamp, the discharge arc 123A (FIG. 2A) generated between the electrodes 123 may float and come close to or in contact with the inner surface of the light emitting portion 130C of the discharge vessel. As a result, the light emitting unit 130C is locally overheated, and the discharge vessel may be cracked. The inventor of the present application conducted a number of experiments and set conditions for avoiding discharge vessel cracking in a high watt type horizontally lit ceramic metal halide lamp with a rated lamp power of 500 to 1000 W as follows. The arc length is AL = 25 to 34 mm, the shape parameter is AL / D = 1.00 to 2.00, where the unit of D is mm, and the electrode parameter is L / D = 0.60 to 1.00. is there. More preferably, the shape parameter is AL / D = 1.20 to 1.60, and the electrode parameter is L / D = 0.70 to 0.90. Furthermore, the wall surface load is 10 to 30 W / cm ² , more preferably 15 to 20 W / cm ² .

With reference to FIG. 2C, the dimensions between the discharge vessel 130, the sleeve 108, and the outer tube 111 of the ceramic metal halide lamp according to the present embodiment will be described. The distance between the outer surface of the light emitting portion 130C of the central axis 130L and the discharge vessel 130 of the discharge vessel 130, i.e., the outer surface radius of the light emitting unit 130C and R _1. Outer surface radius R ₁ of the light emitting portion 130C is a half of the outer diameter D1 of the light emitting portion 130C. The distance between the inner surface of the central axis line 130L and the sleeve 108 of the discharge vessel 130, i.e., the inner surface radius of sleeve 108 and R _2. The distance between the inner surface of the central axis line 130L and the outer tube 111 of the discharge vessel 130, i.e., the inner surface radius of the outer tube 111 and R _3. Further, the distance between the outer surface of the light emitting portion 130C and the inner surface of the sleeve 108 is defined as an inner clearance t ₁ , and the distance between the outer surface of the sleeve 108 and the inner surface of the outer tube 111 is defined as an outer clearance t ₂ .

Emitting portion outer diameter D1 of 130C, an outer diameter D2 of the sleeve 108, the outer surface radius R ₁ of the light emitting portion 130C, the inner surface radius R _2, the inner surface radius R ₃ of the outer tube 111 of the sleeve 108, the inner clearance t ₁ and, The relationship between the outer gaps t ₂ is expressed by the following equation.

R ₃ = R ₂ + Δts + t ₂ = R ₁ + t ₁ + Δts + t ₂
D1 = 2 × R ₁ = 2 × Δtd + D
D2 = 2 × (R ₂ + Δts)
Here, Δts is the thickness of the sleeve 108, Δtd is the thickness of the light emitting portion 130C, and Δtb is the thickness of the outer tube 111.

  An example of the shape of the outer tube of the lamp will be described with reference to FIGS. 3A, 3B, and 3C. The outer tube of the lamp of FIG. 3A is cylindrical and is referred to as T-shaped (Tubular), and the outer tube of the lamp of FIG. 3B is barrel-shaped and is referred to as B-shaped (Bulged). The outer tube of this lamp is a composite shape of a cylindrical shape and a barrel shape and is called a BT shape. The expression method of the lamp format is defined in JIS 7710, and is displayed by combining alphabets and numbers. The alphabet represents the lamp type, and the number is the nominal value (mm) of the outer diameter of the maximum part. For example, “T48” indicates a T shape and a nominal value of the outer diameter of the maximum portion is 48 mm. Incidentally, the outer tube of the lamp shown in FIGS. 1A and 1B is a composite shape of a cylindrical shape and a cylindrical shape, and is called a TT type. In the specification of the present application, the cylindrical outer tube refers to a T shape, a TT shape, or the like, and refers to a tube in which the outer tube is not expanded at least around the discharge vessel.

  As described above, the inventor of the present application diligently studied means for avoiding the outer tube from becoming high temperature in the high watt type horizontal lighting type ceramic metal halide lamp including the cylindrical outer tube. Therefore, the inventor of the present application has conceived of providing a sleeve between the outer tube and the discharge vessel. In general, it is known in the prior art to provide a cylindrical sleeve between a discharge vessel and an outer tube in a ceramic metal halide lamp. However, in the prior art, the sleeve is provided to prevent the outer tube from being destroyed when the discharge vessel is ruptured. Moreover, the sleeve is used in the case of an outer tube having a swollen center like the BT type, and is not used for a cylindrical outer tube like the T type. Therefore, the inventor of the present application has conducted a number of experiments and confirmed that the use of the sleeve can avoid the high temperature of the cylindrical outer tube.

  The inventor of the present application first set the upper limit of the temperature of the outer tube during lighting. The safety standard regarding the temperature of the outer tube made of hard glass is not specified in the case of a ceramic metal halide lamp, but in the case of a high-pressure sodium lamp, it is specified in IEC60662 (2011). According to this, in the case of Japanese specifications, the upper limit of the outer tube surface temperature during a bare lighting test with rated lamp power is 400 ° C. Therefore, the inventor of the present application has made the condition that the maximum temperature of the outer tube at the time of lighting with the rated lamp power is 400 ° C. or less.

  Below, with reference to Table 1, Table 2, and Table 3, the experiment which the inventor of this application performed and embodiment of this invention are demonstrated. Table 1 shows the specifications and results of ceramic metal halide lamps used in the experiments conducted by the inventors of the present application. The inventor of the present application conducted a number of experiments. Here, as shown in the first column of Table 1, Examples 1 to 4, Comparative Examples 1 to 7, and Conventional Examples 1 to 3 will be described. In addition, Examples 1-4 are the experiment which the inventor of this application performed for the first time this time, and Comparative Examples 1-7 and Conventional Examples 1-3 are the experiment which the inventor of this application already performed, and a known experiment. is there.

  As shown in the second column of Table 1, a lamp with a rated lamp power of 660 W was used as an example of the high watt type, and a lamp with a rated lamp power of 250 W and 400 W was used as an example of the medium watt type. As shown in the third column of Table 1, the shape of the outer tube is mainly cylindrical (T-type and TT-type), but the conventional examples 1 and 2 are BT-type. As described above, the lamp format is displayed by combining alphabets and numbers. The alphabet represents the lamp type, and the number is the nominal value (mm) of the outer diameter of the maximum part. For example, “T48” indicates a T shape and a nominal value of the outer diameter of the maximum portion is 48 mm.

  As shown in the fourth column of Table 1, in Examples 1 to 4, the lighting direction of the lamp is a horizontal lighting type (BH type), but in Comparative Examples 5 and 6 and Conventional Example 1, a vertical lighting type (BU type). ). As shown in the fifth column of Table 1, a case where an inert gas was filled in the outer tube and a case where the outer tube was evacuated were prepared.

  As shown in the sixth column of Table 1, ramps with sleeves were prepared in Examples 1 to 4, but lamps without sleeves were also included in the comparative example and the conventional example. Among Examples 1-4, Comparative Examples 1-7, and Conventional Examples 1-3, it is a high watt type and a horizontal lighting type, and the shape of the outer tube is cylindrical (TT type or T type), and The sleeves 108 are provided only in the first and second embodiments, the comparative example 3, and the conventional example 3.

  The seventh column of Table 1 shows the lighting test result, that is, the measurement result of the maximum temperature of the outer tube surface. It is only Examples 1-4, Comparative Examples 4-7, and Conventional Examples 1-3 that the maximum temperature of the outer tube lit at the rated lamp power is 400 ° C. or lower. However, among these examples, the high watt type and the horizontal lighting type, the outer tube is cylindrical (TT type or T type), and the sleeve 108 is provided in the first and second embodiments. And it is the prior art example 3. However, the outer tube shape of Conventional Example 3 is TT120 as shown in the third column of Table 1. This indicates that the outer tube has a cylindrical shape, but its maximum diameter is 120 mm. The outer diameter of the outer tube of the ceramic metal halide lamp of Conventional Example 3 is relatively large, and there is little possibility that the outer tube 111 is thermally deformed due to high temperature. On the other hand, the outer tube shapes of Examples 1 and 2 are TT67 and TT80, and the outer diameter of the maximum portion of the outer tube is about 80 mm at most. The problem of the high temperature of the outer tube is a lamp having a cylindrical outer tube whose outer diameter is at least 100 mm or less, as in Examples 1 and 2. In the embodiment of the present invention, a lamp having a relatively large outer diameter, such as the lamp of the conventional example 3, is not included.

  The presence or absence of gas in the outer tube in the fifth column of Table 1 will be described. As described above, the discharge vessel 130 is kept at a higher temperature than when the outer tube 111 is filled with an inert gas, the evaporation of the luminescent material is promoted, and the lamp efficiency is increased. On the other hand, the temperature of the outer tube 111 is higher when the outer tube 111 is filled with an inert gas than when the outer tube 111 is evacuated. This can be seen, for example, by comparing Comparative Example 1 and Comparative Example 2. In particular, when the outer tube 111 is a horizontal lighting type and the outer tube 111 is filled with an inert gas, the outer tube is heated. However, in the embodiment of the present invention, although it is a horizontal lighting type, the inside of the outer tube 111 is filled with an inert gas. The reason for this is that the deformation of the outer tube at a high temperature is taken into consideration as described below.

  When the inside of the outer tube 111 is vacuum, a pressure due to atmospheric pressure is applied to the outer surface of the outer tube. Therefore, when the outer tube is thermally deformed, the outer tube contracts so as to approach the discharge vessel. When the distance between the outer tube and the light emitting part of the discharge vessel is locally reduced, the outer tube is locally heated to further increase the thermal deformation. On the other hand, when the outer tube 111 is filled with an inert gas, the outer tube is deformed so as to expand outward due to thermal deformation. Therefore, the distance between the outer tube and the light emitting part of the discharge vessel increases, the temperature of the outer tube decreases, and the deformation stops. Therefore, in order to suppress thermal deformation of the outer tube, it is better to fill the outer tube 111 with an inert gas than to evacuate the inside. In the embodiment of the present invention, since the sleeve 108 is provided, the maximum temperature of the outer tube can be suppressed to 400 ° C. or lower. Therefore, even if the outer tube 111 is filled with an inert gas or evacuated, the outer tube is not thermally deformed. However, considering the case where the outer tube is thermally deformed due to an unexpected situation, it is better to fill the outer tube 111 with an inert gas.

Table 2 shows the outer radius R ₁ of the light emitting portion 130C of the ceramic metal halide lamp used in the experiment conducted by the inventors of the present application, the inner radius R ₂ of the sleeve 108, the inner radius R _{3 of} the outer tube 111, and the inner surface of the outer tube 111. The measurement results of the difference R ₃ −R ₁ between the radius and the outer surface radius of the light emitting portion 130C, the inner gap t ₁ , and the outer gap t ₂ are shown.

Table 3 shows a calculation result of a relationship among the inner gap t ₁ , the outer gap t ₂ , and the rated lamp power P in the ceramic metal halide lamp used in the experiment conducted by the inventors of the present application. The second column of Table 3 is the rated lamp power P, the third column is the measurement result of the maximum temperature of the outer tube, the fourth column is the ratio t ₂ / t ₁ between the inner gap t1 and the outer gap t ₂ , and the fifth column is The ratio R ₃ / P between the inner surface radius R ₃ of the outer tube 111 and the rated lamp power P, and the sixth column is the ratio (t ₁ + t ₂ ) / P of the sum of the two gaps and the rated lamp power P. The significance of the ratio R ₃ / P, the ratio (t ₁ + t ₂ ) / P, and the ratio t ₂ / t ₁ will be described later with reference to FIGS. 4A to 6. The seventh and eighth columns of Table 3 show the drawing numbers using these data.

This will be described with reference to FIGS. 4A and 4B. FIG. 4A is a graph showing the relationship between the rated lamp power P, the inner surface radius R ₃ of the outer tube 111 and the ratio R ₃ / P of the rated lamp power P. The horizontal axis represents the rated lamp power P [W], and the vertical axis represents the ratio R ₃ / P [mm / W]. FIG. 4A is a graph of part of the data in the second and fifth columns of Table 3. As shown in the eighth column of Table 3, the circles in this graph are plotted for Examples 1 to 4, the triangles are plotted for Comparative Examples 3, 5, 6, and 7, and square marks Is a plot of Conventional Example 1.

FIG. 4B is a graph showing the relationship between the ratio R ₃ / P and the maximum temperature of the outer tube surface. The horizontal axis represents the ratio R ₃ / P [mm / W], and the vertical axis represents the maximum temperature [° C.] of the outer tube surface. FIG. 4B is a graph of part of the data in the third and fifth columns of Table 3. As shown in the seventh column of Table 3, the circles in this graph are plotted for Examples 1 to 4, the triangles are plotted for Comparative Examples 2 to 5, and the squares are for Conventional Example 1. -3 are plotted.

Here, the significance of the ratio R ₃ / P [mm / W] will be considered. The inventor of the present application focused on the rated lamp power and the outer diameter of the outer tube as factors affecting the surface temperature of the outer tube. When the rated lamp power is constant, it is assumed that the outer tube surface temperature increases as the outer diameter of the outer tube decreases, and the outer tube surface temperature decreases as the outer diameter of the outer tube increases. Conversely, when the outer diameter of the outer tube is constant, it is assumed that the surface temperature of the outer tube increases if the rated lamp power is increased, and the surface temperature of the outer tube decreases if the rated lamp power is decreased. That is, it can be said that the rated lamp power and the outer diameter of the outer tube have a reciprocal influence on the surface temperature of the outer tube. Therefore, the inventors of the present application set the ratio between the two as a parameter. Note that the unit of the ratio [mm / W] does not have any special physical significance.

In FIG. 4A, Examples 1-4 and Comparative Examples 2-5 are compared. As the rated lamp power increases, the ratio R ₃ / P decreases. However, the value of the ratio R ₃ / P in Conventional Example 1 is larger than the value of R ₃ / P in Examples and Comparative Examples. This is because the shape of the outer tube of the lamp of Conventional Example 1 is the BT type, and the outer diameter of the outer tube is relatively large. In FIG. 4B, it can be said that increasing the ratio R ₃ / P tends to lower the surface temperature of the outer tube. This substantially coincides with the above assumption. However, the embodiment of the present invention does not assume a lamp having a relatively large outer diameter. Therefore, it is necessary to set an upper limit of the ratio R ₃ / P, which will be described later.

This will be described with reference to FIGS. 5A and 5B. FIG. 5A is a graph showing the relationship between the rated lamp power P and the ratio (t ₁ + t ₂ ) / P. The horizontal axis is the rated lamp power P [W], and the vertical axis is the ratio (t ₁ + t ₂ ) / P [mm / W]. FIG. 5A is a graph of part of the data in the second and sixth columns of Table 3. As shown in the eighth column of Table 3, the circles in this graph are plotted for Examples 1 to 4, the triangles are plotted for Comparative Examples 3, 5, 6, and 7, and square marks Is a plot of Conventional Example 1.

FIG. 5B is a graph showing the relationship between the ratio (t ₁ + t ₂ ) / P and the maximum temperature of the outer tube surface. The horizontal axis represents the ratio (t ₁ + t ₂ ) / P [mm / W], and the vertical axis represents the maximum temperature [° C.] of the outer tube surface. FIG. 5B is a graph of part of the data in the third and sixth columns of Table 3. As shown in the eighth column of Table 3, the circles in this graph are plotted for Examples 1 to 4, the triangles are plotted for Comparative Examples 3, 5, 6, and 7, and square marks Is a plot of Conventional Example 1.

Here, the significance of the ratio (t ₁ + t ₂ ) / P [mm / W] will be considered. The inventor of the present application paid attention to the size of the gap between the outer tube and the discharge vessel as a factor that affects the temperature of the surface of the outer tube. If the rated lamp power is constant, reducing the size of the gap between the outer tube and the discharge vessel increases the surface temperature of the outer tube, and increasing the size of the gap between the outer tube and the discharge vessel increases the outer tube's surface temperature. It is assumed that the surface temperature will be low. On the contrary, when the size of the gap between the outer tube and the discharge vessel is constant, increasing the rated lamp power will increase the surface temperature of the outer tube, and decreasing the rated lamp power will decrease the surface temperature of the outer tube. It is assumed that That is, it can be said that the rated lamp power and the dimension of the gap between the outer tube and the discharge vessel have a reciprocal influence on the temperature of the surface of the outer tube. Therefore, the inventors of the present application set the ratio between the two as a parameter. Note that the unit of the ratio [mm / W] does not have any special physical significance. The sum (t ₁ + t ₂ ) of the inner gap t ₁ and the outer gap t ₂ is smaller by the thickness Δts of the sleeve 108 than the gap between the outer tube and the light emitting part of the discharge vessel, but both correspond approximately. You can assume that it is.

In FIG. 5A, Examples 1-4 and Comparative Examples 2-5 are compared. Even if the rated lamp power is increased, the ratio (t ₁ + t ₂ ) / P is equal or smaller. However, the ratio (t ₁ + t ₂ ) / P of Conventional Example 1 is larger than the value of (t ₁ + t ₂ ) / P of the example and the comparative example. This is because the shape of the outer tube of the lamp of Conventional Example 1 is the BT type, and the outer diameter of the outer tube is relatively large.

In FIG. 5B, it can be said that the surface temperature of the outer tube tends to decrease when the ratio (t ₁ + t ₂ ) / P is increased. This substantially coincides with the above assumption. However, the embodiment of the present invention does not assume a lamp having a relatively large outer diameter. Therefore, it is necessary to set an upper limit of the ratio (t ₁ + t ₂ ) / P, which will be described later.

This will be described with reference to FIG. FIG. 6 is a graph showing the relationship between the ratio t ₂ / t1 and the maximum temperature of the outer tube surface. The horizontal axis represents the ratio t ₂ / t ₁ , and the vertical axis represents the maximum temperature [° C.] of the outer tube surface. FIG. 6 is a graph of part of the data in the third and sixth columns of Table 3. As shown in the eighth column of Table 3, the circles in this graph are plotted for Examples 1 to 4, the triangles are plotted for Comparative Examples 3, 5, 6, and 7, and square marks Is a plot of Conventional Example 1.

Here, the significance of the ratio t ₂ / t ₁ will be considered. The inventor of the present application further paid attention to the ratio t ₂ / t ₁ between the inner gap t ₁ and the outer gap t ₂ as a factor that affects the surface temperature of the outer tube. Even if the gap between the outer tube and the light emitting part of the discharge vessel is constant, the surface temperature of the outer tube is assumed to be different if the ratio t ₂ / t ₁ is different. The sum (t ₁ + t ₂ ) of the inner gap t ₁ and the outer gap t ₂ is smaller by the thickness Δts of the sleeve 108 than the gap between the outer tube and the light emitting part of the discharge vessel, but substantially corresponds to both. You can assume that it is. Therefore, the inventors of the present application set the ratio t ₂ / t ₁ of the _two as a parameter.

The inventor of the present application has conducted a number of experiments and studied a preferable magnitude relationship between the outer gap t ₂ and the inner gap t ₁ . When the outer gap t ₂ is smaller than the inner gap t ₁ , the sleeve 108 approaches the outer tube 111. In this case, the heat from the sleeve 108 is directly transmitted to the outer tube 111 without being diffused. As a result, it has been found that the outer tube 111 may be thermally deformed. Accordingly, the inventors of the present application have concluded that the outer gap t ₂ needs to be equal to or larger than the inner gap t ₁ . That is, t ₂ ≧ t ₁ or t ₂ / t ₁ ≧ 1.

However, if the outer gap t ₂ is too larger than the inner gap t ₁ , the sleeve 108 approaches the light emitting unit 130C. In this case, the temperature of the sleeve 108 becomes high. As a result, it has been found that the outer tube 111 may be heated and thermally deformed by heat radiation from the outer surface of the sleeve 108. Therefore, it is necessary to set the lower limit of the ratio t ₂ / t ₁ , which will be described later.

From the graphs of Table 3, FIG. 4B, FIG. 5B and FIG. 6, in the high watt type horizontal lighting type ceramic metal halide lamp having a cylindrical outer tube, the outer tube is prevented from being thermally deformed due to high temperature. As conditions necessary for this, values of the ratio R ₃ / P, the ratio (t ₁ + t ₂ ) / P, and the ratio t ₂ / t ₁ are set. First, the upper limit of R ₃ / P will be considered. The embodiment of the present invention assumes a lamp having a cylindrical outer tube having a relatively small outer diameter. Therefore, when the ratio R ₃ / P of Experimental Examples 1 to 4 is taken into consideration, the upper limit of the ratio R ₃ / P is set to 0.06 [mm / W]. In the embodiment of the present invention, the upper limit of the ratio R ₃ / P is 0.06 [mm / W]. The shape of the outer tube is a cylindrical shape such as a T shape or a TT shape, and the BT shape is not included. Next, the lower limit of the ratio R ₃ / P is examined. The rated lamp power is about 600 to 700 W, and may be assumed to be substantially constant. Therefore, taking into consideration the minimum value of the outer diameter of the cylindrical outer tube, the lower limit of the ratio R ₃ / P is at most about 0.010.

Next, consider t ₂ / t ₁ . As described above, the lower limit of the ratio t ₂ / t ₁ has already been set, and t ₂ / t ₁ ≧ 1. Here, an upper limit of the ratio t ₂ / t ₁ is set. As described above, when the value of the ratio t ₂ / t ₁ is too large, the sleeve 108 approaches the light emitting portion of the discharge vessel. Therefore, the upper limit of the ratio t ₂ / t ₁ is set to 2.0.

Next, consider the ratio (t ₁ + t ₂ ) / P. First, the upper limit of the ratio (t ₁ + t ₂ ) / P is examined. In general, the ratio (t ₁ + t ₂ ) / P increases as the outer diameter of the outer tube increases. However, the embodiment of the present invention assumes a cylindrical outer tube having a relatively small outer diameter. Therefore, considering the value of the ratio (t ₁ + t ₂ ) / P in Examples 1 to 4 in Table 3, the upper limit is set to 0.037 [mm / W]. In the embodiment of the present invention, the upper limit of the ratio (t ₁ + t ₂ ) / P is 0.037 [mm / W]. The shape of the outer tube is a cylindrical shape such as a T shape or a TT shape, and the BT shape is not included. Next, the lower limit of the ratio (t ₁ + t ₂ ) / P is examined. Generally, the lower limit is 0.010. This is because if the minimum value of the outer diameter of the cylindrical outer tube is taken into consideration, the lower limit of the ratio (t ₁ + t ₂ ) / P is about 0.010 at most.

The inventor of the present application paid attention to the rated lamp power and the inner clearance t ₁ as factors affecting the surface temperature of the outer tube. If the rated lamp power is constant, by reducing the size of the inner gap t ₁ the surface temperature of the outer tube is high, the surface temperature of the outer tube be lower envisioned by increasing the size of the inner gap t ₁ . On the other hand, when the dimension of the inner gap t ₁ is constant, it is assumed that if the rated lamp power is increased, the surface temperature of the outer tube increases, and if the rated lamp power is decreased, the surface temperature of the outer tube decreases. . That is, it can be said that the dimensions of the rated lamp power and the inner clearance t ₁ have a reciprocal influence on the surface temperature of the outer tube. Therefore, the inventors of the present application set the ratio between the two as a parameter. Note that the unit of the ratio [mm / W] does not have any special physical significance.

When the ratio t ₁ / P in Examples 1 and 2 is calculated from the data in Table 2, the ratio t ₁ / P is about 0.013. Therefore, in a high watt type horizontally lit ceramic metal halide lamp having a cylindrical outer tube, a value of the ratio t ₁ / is necessary as a condition necessary to prevent the outer tube from being thermally deformed due to high temperature. Was t ₁ /P>0.01.

  The ceramic metal halide lamp according to the present embodiment has been described above, but these are examples and do not limit the scope of the present invention. Additions, deletions, changes, improvements, and the like that can be easily made by those skilled in the art with respect to the present embodiment are within the scope of the present invention. The technical scope of the present invention is defined by the appended claims.

  DESCRIPTION OF SYMBOLS 100 ... Ceramic metal halide lamp, 108 ... Sleeve, 109 ... Strut, 110 ... Starter, 111 ... Outer tube, 112 ... Base, 113 ... Getter, 114A, 114B ... Mount support plate, 115 ... Stem tube, 120a, 120b ... Electrode System 121, lead wire 122, current supply conductor 122 a halogen resistant intermediate material 122 b conductive cermet rod 123 123 tungsten electrode 123 A discharge arc 130 discharge vessel 130 A 130 B capillary 130C ... Light emitting unit

Claims (6)

In a ceramic metal halide lamp having a discharge container for storing a luminescent material, and a translucent outer tube for storing the discharge container,
A sleeve is provided between the discharge vessel and the outer tube, the rated lamp power is P [W], the inner surface radius of the outer tube is R ₃ [mm], and the distance between the outer surface of the discharge vessel and the inner surface of the sleeve T ₁ [mm], and the distance between the outer surface of the sleeve and the inner surface of the outer tube is t ₂ [mm], a ceramic metal halide lamp characterized by the following relational expression:
(R ₃ /P)≦0.06 [mm / W]
1.0 ≦ (t ₂ / t ₁ ) ≦ 2.0 2. The ceramic metal halide lamp according to claim 1, further comprising the following relational expression.
(T ₁ + t ₂ ) /P≦0.037 [mm / W] The ceramic metal halide lamp according to claim 1,
The rated lamp power P is 500 W or more, and is a horizontal lighting type, a ceramic metal halide lamp. The ceramic metal halide lamp according to claim 1,
A ceramic metal halide lamp, wherein an inert gas is sealed in the outer tube. 2. The ceramic metal halide lamp according to claim 1, further comprising the following relational expression.
t ₁ /P>0.01 [mm / W] The ceramic metal halide lamp according to claim 1,
A ceramic metal halide lamp, wherein the sleeve is made of quartz glass.

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