CN101082403A - Light source device - Google Patents

Abstract

An object of the present invention is to provide a light source device comprising a discharge lamp and a concave reflector having a front elliptical reflector portion provided with a light emission port and a rear side continuous to the front elliptical reflector portion. The central spherical reflector part, the light source device prevents the light incident on the central spherical reflector part from reciprocating on the straight line passing through the center of the arc and connecting any two points on the reflective surface of the central spherical reflector part, so as to reduce the light emission of the discharge lamp. The proportion of light absorbed by the part, thereby improving the utilization efficiency of light. The light source device includes: a discharge lamp in which a pair of electrodes are oppositely disposed; and a concave reflector having a front elliptical reflector portion provided with a light emission port and a spherical surface continuous with a rear end of the front elliptical reflector portion In the reflector portion, the discharge lamp is disposed with respect to the concave reflector such that the center of the electrodes thereof is located on the front side of a virtual plane including a boundary between the front elliptical reflector portion and the spherical reflector portion.

Description

Light source device

technical field

The present invention relates to a light source device used as a background light for projection type projection devices such as liquid crystal display devices and DLP (registered trademark) (digital light processor) utilizing DMD (registered trademark) (digital mirror device).

Background technique

In a projection-type projection device, it is required to irradiate an image with uniform and sufficient color reproducibility on a rectangular screen. To meet this demand, a short-arc ultra-high pressure mercury lamp with a mercury vapor pressure of 150 atmospheres or more when lit is used in combination with a concave reflector such as an elliptical reflector as a light source.

In recent years, users of projection devices have strongly demanded that projection devices be easily transported and used in various places instead of being permanently installed in conference rooms and the like. Therefore, the size of projection devices has been gradually reduced compared with conventional ones. Moreover, along with the miniaturization of the projection device, the miniaturization of the concave reflector in the light source device is also gradually carried out.

However, simply reducing the size of the concave reflector reduces the effective reflection area of the concave reflector and reduces the luminous flux emitted from the light source device. In addition, in recent years, in addition to the miniaturization of the above-mentioned light source device, the illuminance of the focal point of the projection device has been required to be higher than before. Therefore, only the miniaturization of the concave mirror cannot meet this requirement.

Here, as a technique for improving the utilization efficiency of light beams without reducing the effective reflection area of the concave reflector, Patent No. 3557988 discloses a light source device having a concave reflector composed of the following reflector parts: front reflector A portion forming a light emission port; a central mirror portion positioned behind the front mirror portion; and a rear mirror portion positioned behind the central mirror portion. Hereinafter, the light source device disclosed in the above publication will be described with reference to FIG. 4 .

FIG. 4 is a cross-sectional view showing a schematic configuration of a conventional light source device.

In FIG. 4 , a light source device 10 is composed of a discharge lamp 1 and a concave reflector 2 . The discharge lamp 1 is a discharge lamp of a direct current lighting method, and an anode 13 and a cathode 14 are provided facing each other inside the arc tube portion 11 . The concave reflector 2 is provided so as to surround the discharge lamp 1 with its optical axis Z in the same direction as the direction of the arc of the discharge lamp 1 (the direction in which the anode 13 and the cathode 14 face each other).

The concave mirror 2 is concave as a whole, and is composed of three mirror parts as follows: a front mirror part 22, which has a light emission port 21 in the front; a central mirror part 24, which is connected to the rear end side of the front mirror part 22 ; and the rear mirror portion 26 is continuous with the rear end side of the central mirror portion 24 .

Moreover, the position of the first focal point of the elliptical mirror in the front mirror portion 22, the center position of the spherical mirror in the central mirror portion 24, and the position of the first focal point of the elliptical mirror in the rear mirror portion 26 are the same, Both substantially coincide with the center of the arc of the discharge lamp 1 . In the discharge lamp shown in FIG. 3, the vicinity of the tip of the cathode 14 is the center of the arc. In addition, the position of the second focal point of the elliptical mirror in the front mirror unit 22 is the same as the position of the second focal point of the elliptical mirror in the rear mirror unit 26 .

In the front reflector part 22, the front end edge forming the light emission port 21 is located at a position that protrudes farther forward than the arc tube part 11 of the discharge lamp 1, and its rear end edge is aligned with the central reflector part 24 at the following position. The front end edge of the discharge lamp 1 is connected to: a little behind the vicinity of the center of the arc in the discharge lamp 1 , and a little ahead of the center between the anode 13 and the cathode 14 . In addition, the rear end edge of the central mirror portion 24 is continuous with the front end edge of the rear mirror portion 26 .

According to the light source device of the above-mentioned structure, the light is emitted from the arc formed near the front end of the cathode 14 of the discharge lamp 1, but as shown in FIG. The light emission port 21 at the front end edge of the front mirror portion 22 radiates forward to collect light at the position of the second focal point of the front mirror portion 22 .

On the other hand, since the center of the central mirror portion 24 which is a spherical surface substantially coincides with the center of the arc, among the lights radiated from the arc, the light incident on the central mirror portion 24 behind the front mirror portion 22 is directed towards the arc. The arc light returns, passes through the arc light, and is radiated toward the front mirror portion 22, and is reflected on the front mirror portion 22 to be focused on the position of the second focal point.

According to the light source device having the concave reflector 2 composed of the above-mentioned three reflector parts, in addition to the light incident on the front reflector part 22 which is an elliptical reflector and the central reflector part 24 which is a spherical reflector, The rear reflector portion 26 which is an elliptical reflector directly collects a part of the light emitted to the rear of the arc, which has not been effectively utilized in the past, directly to the front, so that the use efficiency of light is improved.

However, in the light source device described above, it is difficult to increase the illuminance at the light-converging point of the projection device to a level higher than that required by recent projection devices for the following reasons.

In the shaded area in FIG. 5 , as shown by the dotted arrow, among the lights emitted from the arc formed near the front end of the cathode 14 of the discharge lamp 1, the light emitted in the direction perpendicular to the optical axis Z and the light emitted in the direction perpendicular to the optical axis Z are The light radiated in a direction substantially perpendicular to the optical axis Z enters the spherical mirror portion 24 , returns toward the arc, passes through the arc, and enters the spherical mirror portion 24 again. Thereby, the above-mentioned light indicated by the dotted line arrow repeatedly reciprocates on the straight line connecting the center of the arc and any two points on the spherical reflection surface of the central mirror portion 24, and is absorbed by the arc tube portion 11 shortly thereafter, and does not pass through. The front mirror portion 22 radiates from the light emission port 21 .

Furthermore, if the ratio of the light absorbed by the arc tube unit 11 increases among all the lights radiated from the arc, there is a disadvantageous result that the illuminance at the condensing point of the projection device decreases and fails to meet a desired level.

Contents of the invention

Therefore, it is an object of the present invention to provide a light source device comprising a discharge lamp and a concave reflector having a front elliptical reflector portion provided with a light emission port and a rear end connected to the front elliptical reflector portion. The continuous spherical reflector prevents the light incident on the spherical reflector from reciprocating on a straight line connecting the center of the arc and any two points on the reflective surface of the spherical reflector, reducing absorption by the discharge tube of the discharge lamp. The proportion of the light, thereby improving the light utilization efficiency.

In order to solve the above-mentioned problems, the light source device of the present invention includes: a discharge lamp in which a pair of electrodes are opposed to each other; The rear end of the mirror part is connected to the spherical reflector part, and the above-mentioned light source device is characterized in that:

The discharge lamp is disposed with respect to the concave reflector such that the center between the electrodes is located on the front side of a virtual plane including a boundary between the front elliptical reflector portion and the spherical reflector portion.

Furthermore, the above-mentioned light source device is characterized in that: the above-mentioned light source device satisfies the relationship of 90°<X<100° on a cross-section cut on a plane including its optical axis, and the above-mentioned angle X is formed by the following two straight lines: from the above-mentioned electrodes A straight line drawn from the center between the electrodes to the boundary between the front elliptical mirror portion and the spherical mirror portion, and a straight line extending from the center between the electrodes parallel to the optical axis to the light emission direction.

Furthermore, the above-mentioned light source device is characterized in that the concave reflector has a rear elliptical reflector portion continuing to the rear end of the spherical reflector portion.

Furthermore, the concave reflector of the present invention has: a front elliptical reflector part provided with a light emission port; a spherical reflector part continuous with the rear end of the front elliptical reflector part; and a rear elliptical reflector part connected to the spherical surface The rear end of the reflector portion is continuous, and the above-mentioned concave reflector is characterized in that:

The first focal point of the front ellipsoid mirror portion and the first focus of the rear ellipsoid mirror portion are located in front of a virtual plane including a boundary between the front ellipsoid mirror portion and the spherical mirror portion.

According to the present invention, the light source device is composed of a discharge lamp and a concave reflector, the discharge lamp is provided with a pair of electrodes opposite to each other in the discharge vessel, and the concave reflector has a front elliptical reflector portion provided with a light emission port and a front elliptical reflector. The rear end of the surface reflector is connected to the spherical reflector. In the above-mentioned light source device, the discharge lamp is arranged relative to the concave reflector so that the center between the electrodes is located between the front elliptical reflector and the spherical reflector. The front side of the imaginary plane of the boundary part of the part, so all the light incident on the spherical mirror part in the light radiated from the arc returns toward the arc, so that after passing through the arc and incident on the front elliptical mirror part, it is in the front Reflected by the elliptical mirror portion, the light is radiated in the direction of the light emission port and converged at the position of the second focal point. Therefore, the light incident on the spherical reflector portion of the concave reflector does not reciprocate on a straight line connecting the arc center and any two points on the spherical reflective surface of the spherical reflector portion, so the light utilization efficiency of the light source device is improved. .

Description of drawings

FIG. 1 is a cross-sectional view in the longitudinal direction showing a general configuration of a light source device according to the present invention.

Fig. 2 is an enlarged cross-sectional view of an electrode of a discharge lamp according to the present invention.

Fig. 3 is an explanatory view showing the radiation state of light from the light source device of the present invention.

4 is a cross-sectional view in the longitudinal direction showing a general configuration of a conventional light source device.

FIG. 5 is an explanatory view showing the radiation state of light from a conventional light source device.

Detailed ways

Hereinafter, an example of the light source device of the present invention will be described with reference to FIGS. 1 to 3 . FIG. 1 is a cross-sectional view taken along a plane including an optical axis for explaining a light source device of the present invention. Fig. 2 is an enlarged cross-sectional view of the vicinity of a pair of electrodes according to the present invention. Fig. 3 is an explanatory view showing the radiation state of light from the light source device of the present invention. As shown in FIG. 1 , the light source device 10 is configured such that a sealing portion 12 on one side of the discharge lamp 1 is provided in a hole 29 formed on the rear edge of the concave reflector 2, and the concave reflector 2 and the concave reflector 2 are bonded with an adhesive M. The sealing portion 12 is fixed.

Hereinafter, "front" refers to the light emitting direction, and "rear" refers to the hole direction.

The discharge lamp 1 includes a substantially spherical arc tube portion 11 and cylindrical sealing portions 12 connected to both ends of the arc tube portion 11 , and is made of a light-transmitting material such as quartz glass. The discharge lamp 1 is an AC lighting type discharge lamp, and a pair of electrodes 13 and 14 made of tungsten are provided facing each other in the inner space of the arc tube part 11 . The distal ends of the metal foil 15 for power feeding are bonded to the proximal ends of the electrodes 13 and 14 , and the sealing portion 12 is hermetically sealed by the metal foil 15 . The distal end portion of the external lead 16 is bonded to the proximal end portion of the metal foil 15 , and the proximal end portion of the external lead wire 16 protrudes outward from the sealing portion 12 .

Mercury, a halogen gas, and an inert gas are sealed in the inner space of the arc tube 11 . Mercury as a luminescent substance of 0.2 mg/mm ³ or more is enclosed so that the mercury vapor pressure in the internal space at the time of lighting is 200 atmospheres or more. As for the halogen gas, 10 ^-6 μmol/mm3 to 10 ^-2 μmol/mm3 is enclosed mainly in order to prevent blackening of the inner wall of the arc tube portion 11 due to halogen elements. As for the inert gas, for example, argon gas of about 0.0133 MPa is enclosed in order to improve the starting assist performance.

As shown in Figure 2, the electrode 13 is composed of a large-diameter electrode tip 131 and an electrode core rod 132, the electrode tip 131 is opposite to the electrode tip 141 of the other electrode 14, and the diameter of the electrode core rod 132 is smaller than that of the electrode. The front end portion 131 is connected to the base end portion of the electrode front end portion 131 . The electrode tip portion 131 is constituted by a protruding portion 131A, a large-diameter portion 131B continuous to the protruding portion 131A, and a coil-shaped starting assisting portion 131C continuous to the large-diameter portion 131B.

The protrusion 131A is formed by the front end of the electrode core rod 132 , and is equal to the outer diameter of the electrode core rod 132 , or slightly larger or slightly smaller than the outer diameter of the electrode core rod 132 due to melting. That is, the protrusion 131A is not generated and grows due to the lighting of the ultra-high pressure mercury lamp, but is still formed by the tip of the electrode core rod 132 .

The large-diameter portion 131B, for example, melts a part of the tungsten wire wound in a coil shape on the electrode core rod 132 to form a lump, thereby improving the heat capacity.

The starting assisting portion 131C is formed of a coil-shaped portion that was not melted when the above-mentioned large-diameter portion 131B was formed. When starting the ultra-high pressure mercury lamp, since the starting auxiliary part 131C has a coil shape, the gap between the pitches of the coils is easy to become the starting point of discharge, and because of the coil shape, it is easy to heat, so that it can quickly change from glow discharge to arc discharge. When the ultra-high pressure mercury lamp is turned on stably, since the start assisting part 131C has a coil shape, it has a function of releasing heat due to the uneven effect of the surface and heat capacity.

The other side electrode 14 is formed in the same manner as the one side electrode 13 . That is, it is composed of a large-diameter electrode tip portion 141 and an electrode core rod 142 . The electrode tip portion 141 faces the electrode tip portion 131 of one electrode 13 . , and continue on the base end portion of the electrode front end portion 141 . The electrode tip portion 141 is composed of a protruding portion 141A, a large-diameter portion 141B continuing to the protruding portion 141A, and a coil-shaped starting assisting portion 141C continuing to the large-diameter portion 141B.

The concave reflector 2 forms a light emission port 21 at the front edge of the reflection surface, and is continuously formed with a rear end of the reflection surface with a cylindrical hole 29 extending in the optical axis direction and supporting the discharge lamp, and is embedded in the light emission port 21. Has front glass 3. The purpose of providing the front glass 3 is to prevent fragments of the lamp from flying toward the projection device in case the discharge lamp breaks. A lamp through hole 31 through which the sealing portion 12 of the discharge lamp is passed is formed substantially in the center of the front glass 3 , and a part of the sealing portion 12 protrudes outward from the concave reflector 2 .

The concave reflector 2 includes the following three reflective surfaces: a front elliptical reflector portion 22, which is provided with a light emission port 21; a spherical reflector portion 24, whose front end is continuous with the rear end of the forward elliptical reflector portion 22; The front end of the surface mirror portion 26 is continuous with the rear end of the spherical mirror portion 24 . The front ellipsoidal mirror part 22, the spherical mirror part 24, and the rear ellipsoidal mirror part 26 may be formed integrally, or may be formed by connecting a plurality of independent parts. In the concave mirror 2, the position of the first focal point of the front elliptical mirror part 22 and the position of the first focal point of the rear ellipsoid mirror part 26 are the same, and they are located in the front elliptical mirror part 22 and the spherical mirror part. 24 in front of the imaginary plane of the boundary portion P1. In addition, the position of the second focal point of the front ellipsoid mirror portion 22 is the same as the position of the second focus of the rear ellipsoid mirror portion 26 .

The concave mirror 2 is made of, for example, a glass material such as quartz glass, and a reflective film having a property of reflecting visible light and transmitting infrared light and ultraviolet light is formed on the inner surface by vapor deposition or the like. As the reflective film, for example, a reflective film in which silicon dioxide (SiO ₂ ) and titanium dioxide (TiO ₂ ) are laminated is used.

The material constituting the concave mirror 2 is not limited to glass materials such as quartz glass, and metal materials such as copper, brass, iron, aluminum, silver, or alloys thereof may be used. As the material constituting the concave reflector, when using materials such as copper, brass, iron, etc. that do not have reflective properties, it is necessary to provide the above-mentioned reflective film that has the property of reflecting visible light on the inner surface of the concave reflector 2. .

On the other hand, when a material having reflective properties such as aluminum or silver is used as the material constituting the mirror, it is not necessary to form a reflective film that reflects visible light on the inner surface of the concave mirror 2 . However, at this time, since the concave reflector 2 reflects infrared light as well as visible light, it is necessary to coat the front glass 3 embedded in the light emission port 21 of the concave reflector 2 with a substance that absorbs infrared light. Or outside the concave reflector 2, a unit for absorbing infrared light is provided near the front glass 3. As another unit for absorbing infrared light, if the inner surface of the concave reflector 2 is coated with low thermal expansion glass or the like containing chromium, the infrared light can be absorbed, and the outside of the concave reflector 2 can be cooled. , so that the temperature inside the concave mirror can be avoided from rising too much, so this unit is preferred.

In the light source device 10 according to the present invention, the front end edge of the front elliptical reflector portion 22 is provided at a position protruding farther forward than the arc tube portion 11 of the discharge lamp 1 . In the discharge lamp 1 according to the present invention, since bright spots are formed near the protrusions 131A and 141A, the central position P2 between the electrodes 13 and 14 of the discharge lamp 1 is closely related to the front elliptical reflector portion 22 and the rear elliptical reflector portion. 26 coincides with the first focal point, and coincides with the center position of the spherical mirror portion 24 .

Furthermore, the light source device according to the present invention is characterized in that the center P2 between the electrodes 13, 14 is located on the front side of the rear end edge of the front elliptical reflector part 22 or the front end edge of the spherical reflector part 24, that is, on the front elliptical surface. The front side of the boundary portion P1 between the mirror portion 22 and the spherical mirror portion 24 . Hereinafter, the center P2 between the electrodes 13 and 14 may also be simply referred to as the "inter-electrode center P2", and the boundary P1 between the front elliptical mirror portion 22 and the spherical mirror portion 24 may also be simply referred to as the "boundary portion P1".

As shown in FIG. 3 , according to the light source device described above, the lights L1 and L2 directly incident on the front elliptical mirror portion 22 are focused on the position of the second focal point of the front elliptical mirror portion 22 . The light L3 incident on the spherical mirror portion 24 returns to the arc, passes through the arc, and is reflected by the front ellipsoid mirror portion 22 to be focused on the second focal point of the front ellipsoid mirror portion 22 . The light L4 incident on the rear ellipsoidal mirror 26 is reflected by the rear ellipsoidal mirror portion 26 to be focused on the position of the second focal point.

That is, according to the example shown in FIG. 3 , the center P2 between the electrodes is located on the front side of the boundary portion P1, so that the light emitted in the direction perpendicular to the optical axis Z has become a problem in the conventional light source device shown in FIG. 5 . The light L2 is directly incident on the front elliptical mirror part 22, so that the above-mentioned light L2 does not reciprocate on the straight line connecting the center P2 between the electrodes and any two points on the spherical mirror part 24, so that the light can be condensed. The illuminance at the point is higher than that of the existing light source device.

Here, the center P2 between the electrodes is located on the front side of the boundary portion P1, so as described above, the illuminance at the light-converging point can be increased, but when the center P2 between the electrodes is too close to the front side of the boundary portion P1, the light-condensing point The illuminance at the location may not be increased. That is, in order to increase the illuminance at the condensing point, it is necessary to set the position of the center P2 between the electrodes at an optimum position based on its relationship with the boundary portion P1.

Therefore, in the light source device shown in FIG. 1, it is preferable to determine the position of the discharge lamp 1 relative to the concave reflector 2 so that the angle X satisfies the relationship of 90°<X<100°. The above-mentioned angle X is formed by the following two straight lines: A virtual line A between the boundary portion P1 and the center P2 between the electrodes, and a straight line B extending from the center P2 between the electrodes in parallel to the optical axis Z in the direction of light emission. It is preferable to determine the position of the discharge lamp 1 with respect to the concave reflector 2 so as to satisfy this angular range, and it was confirmed by the following experiments. Hereinafter, an experiment conducted to determine the optimum positional relationship between the boundary portion P1 and the center P2 between the electrodes will be described.

Hereinafter, the angle X formed by the virtual line A connecting the boundary portion P1 and the center P2 between the electrodes and the straight line B extending from the center P2 between the electrodes parallel to the optical axis Z to the light radiation direction may also be referred to as "angle X". ".

Example

Based on the structure shown in FIG. 1 , light source devices according to seven examples were produced according to the following specifications.

(discharge lamp 1)

Total length 50mm, distance between electrodes 1mm, mercury inclusion 0.25mg/mm ³ , rated power 200W

(concave mirror 2)

Front elliptical mirror part (22):

It has an elliptical surface with a major axis of 34.05 mm and a minor axis of 19.29 mm, and the opening diameter of the light emission port (21) is 37.2 mm. The overall length in the optical axis direction can be adjusted to 7 types within the range of 15.72 to 20.57 mm.

Spherical mirror part (24):

It has a spherical surface with a radius of 8-12mm. The overall length in the optical axis direction can be adjusted to 7 types within the range of 2.33 to 4.33 mm.

Rear elliptical mirror part (26):

It has an elliptical surface with a major axis of 35.05 mm and a minor axis of 22.29 mm, and the opening diameter of the hole (29) is 10 mm. The overall length in the optical axis direction can be adjusted to 7 types within the range of 1.2 to 3.96 mm.

Seven types of light source devices having different positional relationships between the center P2 and the boundary portion P1 between electrodes were produced using the above-mentioned discharge lamp and seven types of concave reflectors having different overall lengths in the optical axis direction. These seven kinds of light source devices are used as Examples 1-7. In the light source devices of Examples 1 to 7, the distance T (abbreviated as the separation distance T) separating the center P2 between the electrodes shown in FIG. Specifically, it is shown in Table 1 below.

comparative example

Based on the configuration shown in FIG. 4 , a light source device according to a comparative example was fabricated according to the following specifications.

(discharge lamp 1)

Same as Example.

(concave mirror 2)

Front elliptical mirror part (22):

It has an elliptical surface with a major axis of 34.05 mm and a minor axis of 19.29 mm, and the opening diameter of the light emission port (21) is 37.2 mm. The overall length in the optical axis direction is 18.4 mm.

Spherical mirror part (24):

Has a spherical surface with a radius of 11.4 mm. The overall length in the optical axis direction is 4.16 mm.

Rear elliptical mirror part (26):

It has an elliptical surface with a major axis of 35.05 mm and a minor axis of 22.29 mm, and the opening diameter of the hole (29) is 10 mm. The overall length in the optical axis direction is 3.36 mm.

The relationship between separation distance T and angle X is shown in Table 1 below.

The discharge lamps of the light source devices of Examples 1 to 7 and Comparative Example above were turned on, and the light was irradiated onto a screen of 5.0 mm in length and 3.8 mm in width, and the illuminance on the screen was measured. Table 1 shows the results.

In Table 1, the illuminance values obtained by the light source devices according to Examples 1 to 7 are shown as relative values when the illuminance values obtained by the light source devices according to the comparative example are set to 1. In addition, in Table 1, when the separation distance T is a positive value, it represents the state where the center P2 between the electrodes is separated from the boundary portion P1 to the front of the optical axis Z direction, and when the separation distance T is a negative value, it represents the state of the center P2 between the electrodes. P2 is a state separated from the boundary portion P1 toward the rear in the optical axis Z direction.

Table 1

Separation distance T(mm) Angle X(°) Illuminance Example 1 2.36 105.2 0.988 Example 2 1.75 100.0 0.995

Example 3 1.14 96.5 1.014 Example 4 0.90 95.1 1.022 Example 5 0.66 93.6 1.033 Example 6 0.42 92.3 1.048 Example 7 0.17 90.9 1.01

Comparative example -0.55 87.2 1

From the experimental results shown in Table 1, the following facts were judged.

In the light source device according to Embodiments 3 to 7, the position of the discharge lamp relative to the concave reflector is determined such that the center P2 between the electrodes of the discharge lamp is located in front of an imaginary plane including the boundary portion P1 of the concave reflector, and the angle X is in the In the range of 90°<X<100°, compared with the light source device according to the comparative example, the position of the discharge lamp relative to the concave reflector is determined such that the center P2 between the electrodes of the discharge lamp is located at the boundary portion P1 including the concave reflector Compared with the rear of the imaginary plane and the angle X is 87.2°, the illuminance on the screen is increased by 1 to 4.8%.

In particular, it is judged that the above-mentioned angle X satisfies the range of 92.3°≤X≤95.1° in the light source devices related to Examples 4 to 6. Compared with the light source device related to the comparative example, the illuminance on the screen is increased by 2.2 to 4.8%. The illuminance is higher than that of the light source devices involved in other embodiments.

In addition, as shown in Examples 1 and 2, when the above-mentioned angle X is 100° or more, the illuminance on the screen is lower than that of the light source device related to the comparative example, and it is judged that the center P2 between the electrodes is too close to the front of the boundary portion P1. In the light source device, the illuminance on the screen cannot be increased.

According to the light source devices according to Examples 4 to 6, as described above, the illuminance on the screen is improved by 2.2 to 4.8% compared with the light source devices according to Comparative Examples. Generally speaking, in a projection device equipped with a light source device according to the present invention, if the illuminance at the focal point is increased by 1%, it will have a great beneficial effect on the projected image quality on the screen, so the illuminance is increased by 2.2 to 4.8%. % is very large effect.

Furthermore, in order to increase the illuminance by more than 2%, it is usually necessary to increase the amount of mercury enclosed in the discharge lamp, and to increase the input power to the discharge lamp. However, when this method is adopted, new problems arise. more likely. However, the light source device of the present invention has the advantage that the illuminance can be increased higher than that of the existing light source device without increasing the lighting power, and the lighting power required to obtain the same illuminance as the conventional light source device can be reduced, Therefore, it is advantageous to reduce the environmental load.

The light source device of the present invention is not limited to the above-described embodiments, and various changes can be made.

It is also possible to use a concave mirror that is composed of only the front elliptical mirror part and the spherical mirror part connected to the rear end of the front elliptical mirror part, and has two reflective surfaces connected by curved surfaces with different curvatures. Of course, it is also possible to use a concave reflector having four or more reflective surfaces connected by curved surfaces with different curvatures.

In addition, the light reflected by the front elliptical mirror portion and the rear elliptical mirror portion of the concave reflector may be radiated from the light emitting port along the optical axis Z, or the light reflected only on the front elliptical mirror portion or the rear elliptical mirror portion The light reflected by one of the rear elliptical mirror portions is emitted along the optical axis Z from the light emission port.

In addition, when using the discharge lamp 1 in which the thickness of the arc tube part 11 is relatively large in the light source device 10 according to the present invention, the following situation should be considered: the light emitted from the arc formed between the electrodes 13, 14, or the light emitted by the spherical surface. The light reflected by the mirror portion 24 toward the arc is refracted by the lens effect of the arc tube portion 11 when passing through the arc tube portion 11 . At this time, although the light converging on the second focal point of the front ellipsoidal mirror part 22 and the rear ellipsoidal mirror part 26 will slightly decrease, it is preferable to use a mirror that has a rotational ellipsoidal surface that is not strictly spheroidal, but approximately The reflective surface of the ellipsoid of revolution.

Therefore, the front elliptical surface mirror portion 22 in the present invention is not limited to a reflective mirror whose reflective surface shape is a spheroidal surface, but also includes reflective mirrors whose reflective surface shape is not a spheroidal ellipsoid in the strict sense but approximates a spheroidal ellipsoid. .

For the same reason as above, the spherical mirror unit 24 is not limited to mirrors whose mirror shape is spherical, but also includes mirrors whose reflection surface shape is aspheric in the strict sense but approximates to a spherical surface.

Claims (4)

1. light supply apparatus comprises: discharge lamp, and pair of electrodes is oppositely arranged in discharge vessel; And concave mirror, have the place ahead elliptical mirror portion of being provided with the light emission mouth and with the spherical reflector portion of the backhaul of the place ahead elliptical mirror portion, above-mentioned light supply apparatus is characterised in that:

The above-mentioned relatively concave mirror of above-mentioned discharge lamp is arranged to, and it is interelectrode to be centered close to the front side of the imaginary plane of the boundary portion that comprises above-mentioned the place ahead elliptical mirror portion and above-mentioned spherical reflector portion.

2. light supply apparatus according to claim 1 is characterized in that:

Above-mentioned light supply apparatus, on the cross section of blocking with the plane that comprises its optical axis, satisfy the relation of 90 °＜X＜100 °, above-mentioned angle X is formed by following two straight lines: the straight line of drawing to the boundary portion of above-mentioned the place ahead elliptical mirror portion and above-mentioned spherical reflector portion from above-mentioned interelectrode center and be parallel to the straight line of optical axis ground to the extension of light emission direction from above-mentioned interelectrode center.

3. according to claim 1 or the described light supply apparatus of claim 2, it is characterized in that:

Above-mentioned concave mirror has the rear elliptical mirror portion with the backhaul of above-mentioned spherical reflector portion.

4. concave mirror, have: elliptical mirror portion in the place ahead is provided with the light emission mouth; Spherical reflector portion is with the backhaul of the place ahead elliptical mirror portion; And rear elliptical mirror portion, with the backhaul of spherical reflector portion, above-mentioned concave mirror is characterised in that:

The 1st focus of the 1st focus of above-mentioned the place ahead elliptical mirror portion and above-mentioned rear elliptical mirror portion is positioned at the place ahead of the imaginary plane of the boundary portion that comprises above-mentioned the place ahead elliptical mirror portion and above-mentioned spherical reflector portion.

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