JP2005228711A - Optical apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To miniaturize a projector apparatus without producing faults, such as an occurrence of a crack in a sealing portion, disconnection of a power supply line and deterioration of illuminance, by improving a structure of an optical apparatus used in the projector. <P>SOLUTION: The optical apparatus of the present invention comprises a short arc type discharge lamp having a sealing portion formed to be connected with the both ends of a light emission portion having a set of electrodes inside, reflection means for reflecting the light emitted from the discharge lamp to make it pass through an arc luminescent spot, and a condensing reflection mirror for condensing the light from the reflection means on the front side, wherein the sealing portion positioned on the front part of the reflection means is inclined to the side opposite to the side where the reflection means is provided with reference to an optical axis of the condensing reflection mirror. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical device using a short arc type discharge lamp (hereinafter also simply referred to as a discharge lamp), and in particular, a liquid crystal using a short arc type ultra high pressure mercury lamp in which the mercury vapor pressure during lighting reaches 150 atm or higher. The present invention relates to an optical device used as a backlight of a projector device such as a display device or a DLP (digital light processor) using a DMD (digital mirror device).

  In recent years, a projector device capable of displaying an image on a personal computer on a large screen has been attracting attention for applications such as business presentations and academic paper presentations. There are two types of projector devices, one using a liquid crystal panel and the other using a DLP.

  In the method using the liquid crystal panel, after the radiation light from the light source is separated into three colors (RGB), the light corresponding to the image information is transmitted and adjusted in each liquid crystal panel, and then the three colors transmitted through each panel are changed. It is synthesized and projected on the screen. On the other hand, the method using a single plate DLP irradiates the DMD (digital micromirror device) with the radiated light from the light source through a rotary filter in which the RGB region is divided and reflects the specific light with this DMD. To irradiate the screen. DMD is an optical element in which each small mirror corresponds to one dot (pixel) of an image and millions of mirrors are laid out. By controlling the direction of each small mirror, It controls light projection.

  As an optical device used in the projector device, for example, a short arc type ultra-high pressure mercury lamp in which mercury is enclosed in a light emitting unit, and a parabolic reflector for converting light emitted from the lamp into parallel light, What is composed of is known. In such an optical device, it is necessary to efficiently convert light emitted from a lamp as a light source into light parallel to the optical axis and to irradiate an irradiated area of the liquid crystal display panel. In recent years, there has been a strong demand for miniaturization of the projector device so that the projector device can be easily carried in the home and does not occupy excessive space.

FIG. 6 is a side sectional view for explaining the configuration of a conventional optical device. In addition, in the following FIGS. 6-8, although light is radiated | emitted also to the downward direction of a paper surface, only the upward direction is shown for convenience.
The optical device 60 is configured by incorporating a short arc type discharge lamp 64 into a parabolic reflecting mirror 61. In the discharge lamp 64, an anode 67 and a cathode 68 are disposed opposite to each other in a substantially spherical light emitting portion 65, and embedded in sealing portions 66a and 66b formed continuously at both ends of the light emitting portion 65. Connected to the metal foils 69a and 69b are power supply external leads 70a and 70b extending outward from the sealing portions 66a and 66b. In the discharge lamp 64, the arc direction coincides with the optical axis X of the parabolic reflector 61, and the arc bright spot A formed between the anode 67 and the cathode 68 is the focal point F of the parabolic reflector 61. ₁ and one sealing portion 66b is fixed by filling an adhesive 71 into a through hole 63 described later. The parabolic reflecting mirror 61 is provided with a dielectric multilayer film mainly for reflecting visible light on its inner surface, and a front opening 62 provided on the front side (right direction in FIG. 6), It has a through hole 63 formed on the rear side (left direction in FIG. 6) for inserting one sealing portion 66b of the discharge lamp 64.

  In the optical device 60, a virtual straight line C connecting the point B on the front opening edge of the parabolic reflector 61 and the arc bright spot A, the point D on the opening edge of the through hole 63, and the arc bright spot A The parabolic reflecting mirror 61 other than the light radiated toward the region of the angle σ (hereinafter referred to as the light receiving solid angle) formed by the imaginary straight line E connecting the two and the through-hole 63 is used. The light is reflected by the light and becomes parallel light parallel to the optical axis X, and is irradiated on the irradiated region of the liquid crystal display panel.

  In order to reduce the size of the projector, it is conceivable to use an elliptical reflecting mirror with a short focal point instead of the parabolic reflecting mirror 61 shown in FIG. However, when a short-focus elliptical reflecting mirror is used, the light flux condensed by the elliptical reflecting mirror 90 is sealed 66a of the discharge lamp 64 positioned on the front side of the elliptical reflecting mirror 90 as shown in FIG. Furthermore, there is a possibility of hitting the power supply line 72 connected to the external lead 70a extending outward from the sealing portion 66a. In this case, the sealing portion 66a and the power supply line 72 are heated, causing oxidation of the metal foil 69a and the external lead 70a embedded in the sealing portion 66a, generating cracks in the sealing portion 66a, and externally. Problems such as disconnection of the lead 70a and a decrease in illuminance occur.

  In order to avoid the occurrence of the above problems, for example, the following five methods are conceivable. FIG. 8 is a diagram for explaining means for avoiding a problem. The same reference numerals as those in FIGS.

The first to third methods are methods for improving the structure of the discharge lamp 64. As a first method, as shown in FIG. 8A, it is conceivable that a part of the front end side of the sealing portion 66a disposed on the front side of the elliptical reflecting mirror 90 is tapered (Patent Document 1). According to this method, it is possible to avoid the light beam from colliding with the sealing portion 66a,
Oxidation due to heating of the feeder 72 connected to the external lead 70a on the front side cannot be prevented.
As a second method, as shown in FIG. 8B, it is conceivable to shorten the entire length of the sealing portion 66a arranged on the front side of the elliptical reflecting mirror 90. According to this method, however, the sealing portion The temperature drop due to the temperature gradient is reduced. As a result, the temperature of the end face of the sealing portion increases, and the metal foil 69a and the external lead 70a are more easily oxidized.
As a third method, as shown in FIG. 8C, it is conceivable to provide a reflective film on the sealing portion 66a arranged on the front side of the elliptical reflecting mirror 90. According to this method, the sealing portion Although the heat absorption can be reduced by reflecting the light beam that hits 66a, the light beam cannot be reflected 100%, so that the oxidation of the metal foil 69a and the external lead 70a due to the heating of the sealing portion 66a is completely performed. It cannot be prevented.

The fourth and fifth methods are methods for improving the structure of the elliptical reflecting mirror 90. In the fourth method, as shown in FIG. 8D, the diameter of the through hole 63 formed on the rear side of the elliptical reflecting mirror 90 for inserting the sealing portion 66b is increased. According to this method, the light beam that passes through the through hole in the light emitted from the arc bright spot A is increased, that is, the light receiving solid angle is reduced, so that the light beam does not collide with the sealing portion 66a. Therefore, although the trouble due to heating of the sealing portion 66a and the external lead 70a can be avoided, the amount of light captured by the elliptical condensing mirror 90 is reduced, so that the illuminance is remarkably lowered.
Fifth method, as shown in FIG. 8 (e), by using a first focal length f ₁ is larger elliptical reflector 90, disposed discharge lamp 64 as the light emitting portion 65 is positioned more forward side doing. According to this method, although it so that not hit the light beam to the sealing portion 66a without reducing the light receiving solid angle, the front-side opening of the ellipsoidal reflector 90 along with to increase the first focal length f ₁ Since the diameter of 62 also increases, the object of downsizing the projector device cannot be achieved.

As described above, the method of improving the structure of the discharge lamp 64 as in the first to third methods cannot avoid the problem that the sealing portion 66a and the external lead 70a are oxidized by heating. In the method of improving the structure of the elliptical reflecting mirror 90 as in the fourth and fifth methods, it is possible to avoid the problem that the sealing portion 66a and the external lead 70a are oxidized, but the purpose is to reduce the illuminance and further reduce the size. Cannot be achieved. Therefore, in the conventional technology, the projector device cannot be downsized well without causing the above-described problems.
JP 2001-35203 A

  An object of the present invention is to reduce the size of a projector device by improving the configuration of an optical device used in the projector device without causing problems such as cracks in a sealing portion, disconnection of a power supply line, and a decrease in illuminance. For the purpose.

  An optical device according to the present invention includes a short arc discharge lamp having a sealing portion formed continuously at both ends of a light emitting portion having a pair of electrodes therein, and discharge light emitted from the discharge lamp. A reflecting means for reflecting the light so that it passes through the arc bright spot, and a condensing reflector for condensing the emitted light forward so as to overlap the arc bright spot and the focal point. And the sealing portion located on the front side of the discharge lamp is inclined with respect to the optical axis of the condensing reflector to the side opposite to the side where the reflecting portion is provided with respect to the optical axis. It is characterized by that.

  Furthermore, the optical apparatus according to claim 1, wherein the condensing reflector has a substantially halved shape.

  Furthermore, in the optical device according to claim 1, the condensing reflector is a cross section obtained by cutting the condensing reflector from a plane orthogonal to the optical axis at a location where the reflecting portion is provided. An angle formed by a virtual line connecting the opening end of the optical axis and the optical axis and a virtual line connecting the other opening end and the optical axis is 180 ° or less.

  Further, in the optical device according to any one of claims 1 to 3, the reflecting means is a reflecting film provided on an outer surface of the light emitting section.

  Further, in the optical device according to any one of claims 1 to 4, an angle formed by the optical axis of the condenser reflector and the axis of the discharge lamp is 2.65 ° or more.

  According to the optical device of the present invention, the axis of the short arc type discharge lamp incorporated in the elliptical reflecting mirror is inclined with respect to the optical axis of the condensing reflecting mirror. Therefore, even if a condensing reflector with a short focal length is used in order to reduce the size of the projector device, the light flux is applied to the front-side sealing portion or the power supply line that extends outward from the sealing portion and is connected to the external lead. Therefore, the metal foil embedded in the sealing portion and the external lead are not oxidized, and the illuminance is not lowered. Further, the illuminance is not lowered by the shadow of the power supply line connected to the external lead.

  Furthermore, when a half-shaped condensing reflector is used, the following effects can be obtained in addition to the above effects. That is, since the size of the optical device can be reduced to about half compared with the case where a normal condensing reflector is used, the projector device can be further downsized. Moreover, even if a half-shaped condensing reflector is used for downsizing as described above, the light emitted to the upper side of the light emitting part, that is, the side where the condensing reflector is disposed is of course. In addition, since the light radiated downward from the light emitting unit is reflected by the reflective film or the spherical reflecting mirror provided in the vicinity of the light emitting unit so that the light is received by the condensing reflecting mirror, the use efficiency of the emitted light is reduced There is nothing.

Examples of the optical apparatus of the present invention will be described below with reference to FIGS. FIG. 1 is a side sectional view for explaining the configuration of the optical apparatus of the present invention.
The optical device 1 is configured by incorporating a short arc discharge lamp 10 into an elliptical condensing reflecting mirror 20 having a substantially halved shape. The discharge vessel of the short arc type discharge lamp 10 includes a substantially spherical light emitting part 11 and sealing parts 12 a and 12 b formed continuously at both ends of the light emitting part 11. In the light emitting unit 11, an anode 13 and a cathode 14 are arranged to face each other. The sealing portions 12a and 12b are hermetically sealed by embedding metal foils 15a and 15b made of molybdenum, respectively. The metal foil 15a has one end connected to the cathode 14 by, for example, spot welding, and the other end connected to an external lead 16a for power supply extending outward from the sealing portion 12a. Similarly to the metal foil 15a, the metal foil 15b is connected to the anode 13 and the external lead 16b. The external lead 16a is connected to a power supply line 17 connected to a lighting power source (not shown).

The condensing reflecting mirror 20 has a front part 21 and a rear part 22, and is an elliptical reflecting mirror that is substantially halved. The front part 21 is a front opening 62 in FIG. These correspond to the through holes 63 in FIG. In addition, a reflection portion 23 made of a dielectric multilayer film for mainly reflecting visible light is formed on the inner surface of the condenser reflector 20. In the short arc type discharge lamp 10, the arc bright spot A overlaps the first focal point F ₁ of the condensing reflector 20, and the axis Y of the discharge lamp is relative to the optical axis X of the condensing reflector 20. The optical axis X is incorporated in the converging reflector 20 in an inclined state at an angle α formed by the axis Y and the optical axis X toward the side opposite to the side where the reflecting portion 23 is formed.
Thereby, the sealing part 12a located in the front part 21 side inclines toward the opposite side to the side in which the reflection part 23 was formed on the basis of the optical axis X with respect to the optical axis X. . In the discharge lamp 10, the arc luminescent spot A is formed when the lamp is turned on, and is not formed when the lamp is turned off. 13 and so that the intermediate position) and the first focus F ₁ of the cathode 14 is disposed so as substantially to match. In the present invention, the use of the collecting mirror reflector, the second focal point F ₂ of the collecting mirror reflector 20 is generally consistent with the distal end of the integrator lens 100 of the rod-shaped.

The condensing reflection mirror 20 is made of, for example, crystallized glass, and a reflection portion 23 made of a dielectric multilayer film of TiO ₂ and SiO ₂ is formed on the inner surface thereof so as to mainly reflect visible light. ing. The discharge lamp 10 is fixed to the condenser reflector 20 by filling the back part 23 with the adhesive 24 in a state where the sealing part 12b is inserted into the back part 23.

The short arc type discharge lamp 10 is a reflection film 2 on the outer surface of the light emitting portion 11 and on the lower half thereof, that is, on the side opposite to the side where the reflecting portion 20 is formed around the optical axis X of the condensing reflecting mirror 20. Is formed. The reflective film 2 is, for example, a multilayer film of ZrO and SiO ₂ and is coated on the lower half of the light emitting unit 11 by, for example, sputtering. The reason why such a material is used is that the discharge lamp 10 having the numerical examples described later has a high heat resistance because the temperature of the outer surface of the light emitting unit 11 reaches a high temperature of 800 ° C. or higher during lighting. Because. Further, the discharge lamp 10 has a discharge vessel made of quartz glass, and mercury for obtaining emitted light having a visible light wavelength of 400 nm to 750 nm, for example, necessary for the projector device is enclosed in the light emitting unit 11. Yes. Further, in the light emitting unit 11, iodine, bromine, chlorine, or the like is used to prevent blackening of the light emitting unit 11 by performing a halogen cycle with a rare gas such as argon or xenon in order to improve lighting startability. Halogen gas is enclosed.

FIG. 2 is a cross-sectional view obtained by cutting the optical device 1 of the present invention along the YZ plane including the GG ′ line, as viewed from the front side. The GG ′ line is orthogonal to the optical axis X. 1 denote the same parts.
As shown in FIG. 2, the light emitting portion 11 of the discharge lamp 10 is provided with a reflective film 2 in the lower half. The advantage of providing the reflective film 2 below the light emitting part will be described below. The discharge lamp 10 according to the present invention has very severe thermal conditions such that the mercury vapor pressure during lighting in the light emitting unit 11 having a small internal volume reaches 150 atm or more as shown in numerical examples described later. For this reason, the light-emitting portion 11 becomes extremely hot during lighting. In this case, since the temperature above the light emitting unit 11 is higher than that below, the reflective film 2 is less likely to be deteriorated by providing the reflective film 2 on the lower side, which is the low temperature part of the light emitting unit 11.

Numerical examples of the optical device 1 are shown below. The condensing reflector 20 is selected from a range of 40 to 50 mm, for example, if it is a virtual opening circle in which the opening diameter on the front side is not halved, for example 44 mm, and the opening diameter on the rear side is not halved The virtual opening circle is selected from the range of 9 to 12 mm, for example, 11 mm. The thickness of the condenser reflector 20 is selected from the range of 3 to 6 mm, and is 4 mm, for example. Collecting mirror reflector 20, a first focal length _{f 1} is selected from the range of 6 to 12 mm, for example, 8.1 mm, the second focal length _{f 2} is selected from the range of 50 to 300 mm, for example 64 .1 mm.

The short arc type discharge lamp 10 has a total length in the arc direction selected from a range of 45 to 120 mm, for example, 65 mm, and an interelectrode distance between the anode 13 and the cathode 14 is selected from a range of 1 to 2 mm. For example, it is 1.2 mm. The light emitting portion 11 has a maximum outer diameter selected from a range of 9 to 14 mm, for example, 10 mm, and the sealing portion 12 has an outer diameter selected from a range of 5 to 8 mm, for example, 6 mm. The length from the base to the end of the sealing portion is selected from the range of 15 to 50 mm, for example, 25 mm. The reflective film 2 coated on the outer surface of the light emitting unit 11 is selected from the range of 0.6 to 1.2 μm in thickness, for example, 0.9 μm.
An amount of mercury selected from the range of 50 to 200 mg according to the internal volume of the light emitting unit 11 is enclosed in the light emitting unit 11 such that the amount of enclosed mercury is 0.15 mg / mm ³ or more. Moreover, Ar or Xe is enclosed in the light emission part 11 in the range of 10-20 kPa as buffer gas. The amount of enclosure at this time is, for example, 13 kPa. Further, bromine as the halogen gas is selected from the range of 10 ⁻⁷ to 10 ⁻² μmol / mm ³ at the time of sealing, and, for example, 10 ⁻⁵ μmol / mm ^{3 is} sealed in the light emitting unit 11. Such a discharge lamp 10 has a rated voltage selected from a range of 60 to 110V, and is generally lit horizontally at 80V, for example.

As shown in FIG. 1, in the optical device 1, the short arc type discharge lamp 10 has a structure in which the axis Y is inclined with respect to the optical axis X of the condenser reflector 20. An angle formed by the axis Y and the optical axis X is α. Here, when the numerical example of the optical device 1 is as follows, α is preferably 2.65 ° or more so that the light beam does not collide with the sealing portion 12a on the front side.
<Numerical example of the optical apparatus 1>
Maximum outer diameter of the light emitting part 11: 10 mm
Outer diameter of the sealing part 12a: 6 mm
First focal length: 8.1 mm
Second focal length: 64.1 mm
Distance from arc bright spot A to front side end of sealing part 12a: 25 mm

The radiation state of the radiated light in the optical device 1 will be described. The arc bright spot A formed between the anode 13 and the cathode 14 becomes a radiation source. The light beam emitted above the light emitting unit 11 is reflected by the reflecting unit 23 and emitted as light beams I1, I2, I3, and I4 to be collected at the second focal point F2. The light beam radiated to the lower side of the light emitting unit 11 is reflected by the reflecting film 2 and passes through the arc bright spot A, and then is radiated by the reflecting unit 23 as I1, I2, I3, and I4 as described above.
Here, it is preferable that the light emitting portion 11 is completely spherical in the portion where the reflective film 2 is coated. The reason is that the radiation from the arc luminescent spot A, which is considered to be a point ideally, can be returned to the arc luminescent spot A again by the reflective film 2.

  According to such an optical device 1, since the condensing reflecting mirror 20 has a halved shape, there is an advantage that the overall size can be remarkably reduced. For example, a conventional condensing reflector having an opening diameter of 44 mm is half that of 22 mm. That is, even if the dimensions of the light emitting unit 11 are taken into account, the optical device 1 can be sufficiently mounted if the space in the projector device where the optical device is to be mounted is about 35 mm. Further, since the light beam is not radiated to the lower side of the light emitting portion 11 of the discharge lamp 10, there is no fear that the feeder line 17 becomes a shadow as in the conventional optical device shown in FIG. Further, the discharge lamp 10 is arranged with the sealing portion 12a positioned on the front side thereof being inclined with respect to the optical axis of the condensing reflection mirror 20, and the luminous fluxes I1, I2, I3, Since I4 does not hit the sealing portion 12a, the sealing portion 12a and the external lead 16a are not heated, and this is the greatest feature of the present invention without causing a decrease in illuminance.

  The present invention is not limited to the above-described embodiments, and appropriate modifications can be made. Hereinafter, another embodiment of the present invention will be described with reference to FIGS. The same reference numerals as those in FIG.

FIG. 3 shows another embodiment of the optical device of the present invention. FIG. 3 corresponds to FIG. 1 and shows a side sectional view of the optical device. In the above-described embodiments, the “reflecting film” is used as the “reflecting means” in the first embodiment. However, the present invention is not limited to this. As shown in FIG. 3, the short arc type discharge lamp 10 is surrounded by a reflecting mirror 20, a light transmission window 31, a bottom plate 25, and a side plate 26 fixed to the bottom plate 25, and is generally sealed. Then, the spherical reflector 30 for reflecting the light emitted from the lower side of the light emitting unit 11 through the arc bright spot A is supported by the support member 27 attached to the bottom plate 25, and the lower light emitting unit. 11 is arranged in the vicinity. Other methods for fixing the spherical reflector near the light emitting portion include a method in which the spherical reflector 30 is directly attached to the bottom plate 25 and a method in which the spherical reflector 30 is fixed to the sealing portion 12a or the sealing portion 12b. . The bottom plate 25 is formed with a through hole 29 for drawing out the feeder line 17.
In addition, in order to return the light emitted from the lower side of the light emitting unit 11 to the arc bright spot A, not only the spherical focusing mirror but also a reflecting mirror having another structure such as an elliptical focusing mirror can be used. .

  According to the optical device shown in FIG. 3, since the discharge lamp 10 has a substantially sealed structure, the discharge lamp 10 can be isolated as a separate space in the projector apparatus. Thereby, unnecessary interference between the components of the projector apparatus that are crowded in the projector apparatus and the discharge lamp can be prevented, and the optical apparatus 1 can be taken out from the projector apparatus as a whole, so that the discharge lamp 10 can be replaced. In addition, it is possible to prevent the projector apparatus from being damaged due to scattering of glass pieces or the like even if the discharge lamp 10 is broken.

FIG. 4 shows another embodiment of the optical device of the present invention. FIG. 4A corresponds to FIGS. 1 and 3 and shows a side sectional view of the optical device. FIG. 4B corresponds to FIG. 2 and shows a cross-sectional view obtained by cutting the optical device along a YZ plane including the line HH ′. The HH ′ line is orthogonal to the optical axis X.
The collecting / reflecting mirror 20 does not necessarily need to be completely halved. As shown in FIG. 4B, the optical axis X of the collecting / reflecting mirror 20 and the front opening edge of the collecting / reflecting mirror 20 are provided. An angle β formed by a virtual straight line M connecting the point J and a virtual line N connecting the optical axis X and the point K on the front opening edge may be formed in a range of 180 ° or less. In this case, the reflective film 2 may be coated on the outer surface of the light emitting unit 11 in a portion corresponding to the angle β. Also with the optical device of this embodiment, it is possible to condense all the light emitted to the lower side of the light emitting unit 11 at the second focal point F2.

  According to the optical device 1 shown in FIG. 4, since the condensing reflector 20 has the neck portion 32 that can cover the outer periphery of the sealing portion 12b, it is smaller than the optical device 1 shown in FIGS. Although it is inferior in the aspect, there is an advantage that it is easy to fill the adhesive 24 between the sealing portion 12b and the neck portion 32 and the discharge lamp 10 is easily fixed. As a result, the discharge lamp 10 can be reliably fixed at the optimum position with respect to the condenser reflector 20.

FIG. 5 is a side sectional view for explaining another embodiment of the optical apparatus of the present invention. The condensing reflecting mirror 20 is not halved but is the same as the elliptic reflecting mirror 90 shown in FIGS. On the inner surface of the condensing reflecting mirror 20, the upper half, that is, the reflecting portion made of a dielectric multilayer film of TiO ₂ and SiO ₂ , for example, on the portion corresponding to the opposite side of the reflecting film 2 provided on the light emitting portion 11. 23 is formed. Of course, the reflecting portion 23 may be provided on the entire inner surface of the condenser reflector 20. According to the optical apparatus of such an embodiment, the light emitted from the discharge lamp 10 is reflected by the reflecting film 2 and passes through the arc bright spot A, and further reflected by the reflecting portion 23 and is shown in FIG. Similarly flux I1, I2, I3, I4 as will be focused on the second focal point _{F 2} and. In the present embodiment, it is also possible to use a spherical reflecting mirror 30 instead of the reflecting film 2 as in the embodiment shown in FIG.

Such a structure loses the advantage of downsizing the optical device, but has the advantage that the manufacturing process of halving the elliptical reflector is not required, so that only the projector device is required to be downsized. This is effective when miniaturization is not required. Further, since the lower half of the condenser reflector 20 is not optically used, a through hole for drawing out the lead wire 17 and a cooling opening for introducing cooling air into the condenser reflector are formed. You can also.
Furthermore, it has a great advantage as described below. That is, the discharge when the arc radiance spot A of the lamp 10 considered to be ideally point the light reflected by the collecting mirror reflector 20 becomes to converged at the second focus F _2, the real arc point However, there is a light beam that is not condensed at the second focal point F2 because it has a size that dominates a certain space. When condensing light efficiently on a liquid crystal element (LCD) or DLP element that forms an image, the light condensing efficiency becomes higher when the beam diameter of the condensed light beam is smaller, so that the light utilization efficiency is improved.

  Incidentally, according to the optical device shown in the above embodiment, the reflective film 2 is formed by coating below the light emitting portion 11 of the discharge lamp 10, but if a reflective film having excellent thermal characteristics is used, It is also possible to provide a structure in which the reflecting mirror 2 is provided above the light emitting unit 11 and the condensing reflecting mirror 20 is disposed so that the reflected light from the reflecting film can be received.

In addition, the optical apparatus shown in the above embodiment has been described only with respect to an example using a DC lighting type short arc type discharge lamp. However, the present invention is not limited to this, and an AC lighting type discharge lamp may be used. it can.

  Furthermore, as a short arc type discharge lamp used in an optical device, an ultra-high pressure mercury lamp in which the mercury vapor pressure during lighting reaches 150 atm or higher has been described. Instead, a discharge lamp such as a metal halide lamp should be used. Is also possible.

It is a figure for demonstrating the structure of the optical apparatus of this invention. It is a figure for demonstrating the structure of the optical apparatus of this invention. It is a figure for demonstrating the other Example of the optical apparatus of this invention. It is a figure for demonstrating the other Example of the optical apparatus of this invention. It is a figure for demonstrating the other Example of the optical apparatus of this invention. It is a sectional side view for demonstrating the structure of the conventional optical apparatus. It is a figure for demonstrating that a malfunction arises in the conventional optical apparatus. It is a figure for demonstrating the means for malfunction avoidance. It is a figure for demonstrating the means for malfunction avoidance

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Optical apparatus 2 Reflective film 10 Short arc type discharge lamp 11 Light emission part 12 Sealing part 13 Anode 14 Cathode 15 Metal foil 16 External lead 17 Feed line 20 Condensing reflective mirror 21 Front part 22 Back part 23 Reflector 24 Adhesive 25 Bottom plate 26 Side plate 27 Support member 29 Through hole 30 Spherical reflector 31 Light transmission window 32 Neck A Arc bright spot X Optical axis of condensing reflector Y Y axis of discharge lamp

Claims (5)

A short arc type discharge lamp having a sealing portion formed continuously at both ends of a light emitting portion having a pair of electrodes therein, and radiated light emitted from the discharge lamp passes through the arc bright spot of the discharge lamp. An optical system comprising a reflecting means for reflecting the light and a condensing reflecting mirror that is arranged so that the arc bright spot and the focal point overlap each other and has a reflecting portion for condensing the radiated light forward. In the device
In the discharge lamp, a sealing portion positioned on the front side thereof is inclined with respect to the optical axis of the condensing reflecting mirror on the side opposite to the side where the reflecting portion is provided with respect to the optical axis. An optical device. The optical apparatus according to claim 1, wherein the condensing reflector has a substantially halved shape. In the cross section obtained by cutting the light collecting / reflecting mirror by a plane perpendicular to the optical axis at the location where the reflecting portion is provided, the light collecting / reflecting mirror has one opening end and the optical axis. The optical apparatus according to claim 1, wherein an angle formed by a connecting virtual line and a virtual line connecting the other opening end and the optical axis is 180 ° or less. The optical apparatus according to claim 1, wherein the reflection unit is a reflection film provided on an outer surface of the light emitting unit. The optical apparatus according to any one of claims 1 to 4, wherein an angle formed by the optical axis of the condenser reflector and the axis of the discharge lamp is 2.65 ° or more.

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