JP2011159609A - Light source device and projection type display device - Google Patents

Abstract

A light source device that prevents energy loss of microwaves and efficiently discharges a discharge lamp is provided.
A free end of a discharge lamp and an end portion of the discharge lamp that is insulated and fixed to a central conductor, that is, a portion located at a length L from the free end are each of a standing wave electric field. Since it becomes a belly and becomes a node of an electric field of standing wave at the center of the space (encapsulation) portion 31 of the discharge lamp 35 located at the length L / 2 from the free end 36, the light emitting portion 20 of the discharge lamp 35 Microwave power can be efficiently input, and the discharge lamp 35 can emit light efficiently. Moreover, the discharge lamp 35 can be made shorter than a calculated value, and the light source device 1 reduced in size can be obtained. Further, transmission loss is reduced, and light emitted from the discharge lamp 35 can be emitted more efficiently.
[Selection] Figure 1

Description

  The present invention relates to a light source device having a discharge lamp that emits light when irradiated with microwaves, and a projection display device including the light source device.

  Conventionally, discharge lamps using microwaves have a reflector that reflects light in order to prevent leakage of the microwaves. The microwaves are confined in the reflector chamber, and the discharge lamp is placed in the chamber to generate plasma. A configuration for generating light and extracting light is known (for example, see Patent Document 1).

JP 2008-192392A

  However, in order to transmit microwave energy to the discharge lamp in the reflector, matching using a matching machine or the like is performed in front of the reflector so that energy can be put into the discharge lamp with some degree of efficiency. There is a problem that the matching machine is relatively large for mounting. In addition, when using a small and simple matching machine, the matching range is quite narrow, so the standing wave ratio (SWR) value should be 1.2 or less (loss 1% or less). However, there is a problem that microwave energy is lost.

  The present invention has been made to solve at least a part of the above problems. It can be realized by the following forms or application examples.

  [Application Example 1] A light source device according to this application example includes a microwave generation unit that generates a microwave, a central conductor that is connected to the microwave generation unit and radiates the microwave, and is insulated from the central conductor. A discharge lamp that is fixed and is lit by the microwave, a reflector that is formed of a conductive material that surrounds the discharge lamp and is open at one end, and a space in which a luminescent substance is sealed in the discharge lamp And the center of the space is located at half the length L of the discharge lamp.

  According to this, due to the shortening of the wavelength, the free lamp end and the end of the discharge lamp that is insulated and fixed to the central conductor, that is, the portion located at a length L from the free end, respectively, Become annoyed. And since it becomes a node of the electric field of the standing wave at the center of the space (encapsulation) part of the discharge lamp located at the length L / 2 from the free end, the microwave power is efficiently used in the light emitting part of the discharge lamp. The discharge lamp can emit light efficiently.

  Application Example 2 In the light source device according to the application example, it is preferable that the length L of the discharge lamp is less than λ / 2.

  According to this, since a phase shift caused by plasma generation occurs in the discharge lamp, the discharge lamp can be made shorter than the calculated value, and a miniaturized light source device can be obtained. Further, transmission loss is reduced, and light emitted from the discharge lamp can be emitted more efficiently.

  Application Example 3 In the light source device according to the application example, it is preferable that a high-frequency transmission mode transmitted from the microwave generation unit is a TEM (Transverse Electro Magnetic) mode.

  According to this, the light emission from the discharge lamp can be used more efficiently, and the above-described effects can be achieved.

  Application Example 4 In the light source device according to the application example, it is preferable that the reflector or the inner surface of the reflector is a metal.

  According to this, while exhibiting the above-mentioned effect, it can prevent that a high frequency leaks out of a reflector.

  Application Example 5 In the light source device according to the application example, it is preferable that the reflector includes an optical member that efficiently collects or polarizes light on an optical axis of a light beam emitted from the discharge lamp.

  According to this, by providing an optical member such as an optical lens in the reflector, the light guide distance from the light source to the optical member can be shortened, and the light utilization efficiency can be improved. Since a condensing lens, a collimating lens, or the like can be used as the optical member, the light beam can be condensed or collimated at the light beam exit of the light source device, and the degree of freedom in optical design is increased.

  Application Example 6 A projection display device according to this application example includes a microwave generation unit that generates a microwave, a central conductor that is connected to the microwave generation unit and radiates the microwave, and the central conductor. A discharge lamp that is insulated and fixed and discharge-lighted by the microwave, a reflector that is formed of a conductive material that surrounds the discharge lamp and that is open at one end, and a light-emitting substance is enclosed in the discharge lamp. A light source device whose center is located at half the length L of the discharge lamp, and a light beam emitted from the light source device according to input image information. The gist of the invention is that a light modulation unit that modulates and forms an optical image and a projection unit that projects the optical image formed by the light modulation unit are provided.

  According to this, it is possible to provide a projection display device having a highly efficient light source device capable of adjusting the impedance of the coaxial line and having high light use efficiency. Further, it is not necessary to provide a matching machine separately from the light source device, which can contribute to downsizing of the projection display device.

1 is a schematic cross-sectional view illustrating a schematic configuration of a light source device according to a first embodiment. The block diagram which shows schematic structure of the microwave generation part of 1st Embodiment. The schematic sectional drawing which shows the structure of the light source device of a modification. FIG. 6 is a block diagram illustrating a schematic configuration of a projector according to a second embodiment.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. In the drawings used for the following description, the ratio of dimensions of each member is appropriately changed in order to make each member easily recognizable.

(First embodiment)
FIG. 1 is a schematic cross-sectional view illustrating a schematic configuration of the light source device according to the first embodiment.
The light source device 1 includes a microwave generation unit 10 that generates a microwave and a light-emitting unit 20 that uses the microwave to emit light.
The light emitting unit 20 includes a coaxial tube 50, a discharge lamp 35, and a reflector 40.

The coaxial tube 50 has a connector part 52 and a central conductor 30, and is connected to the microwave generation part 10 at the connector part 52.
The central conductor 30 is formed in a cylindrical shape, extends from the microwave generation unit 10 in the direction of the optical axis P, and is provided so that a quartz tube 32 formed of transparent quartz glass covers the outer periphery of the central conductor 30. . Then, the microwave generated by the microwave generator 10 is radiated.
An outer tube 56 is provided so as to surround the central conductor 30 at an equal distance. The center conductor 30 and the outer tube 56 are made of a conductor formed of a metal such as copper or a dielectric formed of quartz glass or the like. Further, in the connector portion 52, an insulating member 53 such as ceramics or fluorine resin is provided between the central conductor 30 and the outer tube 56 so as not to short-circuit.

  A portion of the quartz tube 32 surrounded by the reflector 40 swells in a substantially spherical shape, and a space portion 31 is formed therein, in which a luminescent material is enclosed. In the space portion 31, a central conductor 30 extending from the inside of the microwave generation portion 10 and a conductor 34 extending from the tip of the quartz tube 32 are arranged at a predetermined distance. The central conductor 30 and the discharge lamp 35 are fixed to be insulated. Thus, the central conductor 30, the quartz tube 32, and the discharge lamp 35 are integrated. The dimension from the center of the space (encapsulation) portion 31 of the discharge lamp 35 to the free end 36 of the discharge lamp 35 is a length L / 2, and the entire length of the discharge lamp 35 is a length L.

  The microwave generated by the microwave generator 10 is radiated to the space 31 through the coaxial tube 50, and the plasma is concentrated in the space 31 by the conductor 34 formed and formed at the tip of the quartz tube 32. Accordingly, the discharge lamp 35 emits light by exciting (and ionizing) the light emitting substance in the space 31 and emitting plasma.

As described above, the coaxial tube 50 having the central conductor 30 as the inner conductor and the outer tube 56 as the outer conductor is formed, and microwaves can be transmitted in the direction of the optical axis P.
As a high-frequency transmission mode transmitted from the microwave generation unit 10, a TEM (Transverse Electro Magnetic) mode in which the electric field component and the magnetic field component are zero in the wave propagation direction is used. For this reason, there is little loss of transmission of microwaves, and efficient microwave propagation is possible.
In general, a conventional frequency as a microwave band is 3 GHz to 30 GHz, but in this embodiment, a 300 MHz to 30 GHz band corresponding to a UHF band to an SHF band is defined as a microwave band.

The reflector 40 is formed in a shape in which light is optically parallel or focused, and has an optical free-form surface. The reflector 40 has one end opened and the other end connected to the coaxial tube 50.
The shape of the reflector 40 is such that a portion close to the coaxial tube 50 is formed in a hemispherical shape and extends from there to the opening 42 in a cylindrical shape.
The reflector 40 is made of a metal such as aluminum, which is a conductor material, and is grounded to the ground. In this way, the electromagnetic wave shielded by the reflector 40 is electrically conducted to the ground.

Moreover, the inner surface 41 of the reflector 40 is formed in the mirror surface from which the reflectance of light becomes 90% or more. The inner surface 41 reflects the microwave and guides the light emitted from the discharge lamp 35 to the outside through the opening 42 of the reflector 40.
Even if the entire reflector 40 is not formed of a metal material, the surface of the reflector 40 facing the discharge lamp 35 may be formed of a metal material and electrically connected to the ground. Thereby, the high frequency does not leak out of the reflector 40.

  The center conductor 30 extends from the coaxial tube 50 into the reflector 40, and the center conductor 30 is provided with a discharge lamp 35. The center conductor 30 further extends from the discharge lamp 35.

If the length L, which is the entire length of the discharge lamp 35, is in the range of L <λ / 2, the discharge lamp can be made to emit light efficiently. In detail, if the wavelength λ is shortened and the length L is in the range of L ≦ nλ / 2−θλ / 2 because the phase shift caused by plasma generation occurs in the space (encapsulation) portion 31, the discharge is performed. The lamp can emit light more efficiently. Θ is a physical property value indicating a phase shift caused by plasma generation in the space (encapsulation) portion 31. Here, the lower limit value of the length L depends on the size of the space portion 31 and is considered to be about 7 mm at the time of filing, but if the size of the space portion 31 is less than 7 mm and can be used, the value is It can be applied as a lower limit.
In this embodiment, the overall length of the discharge lamp 35 is length L = 35 mm, and the dimension from the center of the space (enclosed) portion 31 of the discharge lamp 35 to the free end 36 of the discharge lamp 35 is length L / 2 = 17. In the case of 5 mm, it was confirmed that the value was optimal (brightness efficiency).

A reflector 40 is formed so as to surround the discharge lamp 35, and the discharge lamp 35 is disposed at the optical focal position of the reflector 40.
Thus, since the discharge lamp 35 is arranged at the optical focal position of the reflector 40, the light beam emitted from the discharge lamp 35 is derived while being efficiently reflected by the reflector 40, and the optical loss at the time of reflection is reduced. be able to.

The discharge lamp 35 is formed by encapsulating a light emitting substance that emits light by microwaves in a transparent container formed of quartz glass or transparent ceramics which is a non-conductive material. As the luminescent substance enclosed in the space (encapsulation) part 31, a rare gas such as neon, argon, krypton, or xenon, mercury, a metal halide, or the like is used.
The discharge lamp 35 may have an electrode structure having electrodes or an electrodeless structure.

Next, the configuration of the microwave generator of the first embodiment will be described with reference to the drawings.
FIG. 2 is a block diagram illustrating a schematic configuration of the microwave generation unit. The microwave generation unit 10 includes a high-frequency oscillation unit 11 that outputs a high-frequency signal, and a waveguide unit 12 that radiates the high-frequency signal output from the high-frequency oscillation unit 11 as a microwave.

  The high-frequency oscillating unit 11 includes a power source 13, a surface acoustic wave (SAW) oscillator as a high-frequency oscillator, and an amplifier 14. In this embodiment, a diamond SAW oscillator 15 is employed as the surface acoustic wave oscillator. The waveguide unit 12 includes a center conductor 30 and an isolator 16 as a safety device.

The high frequency oscillator 11 will be described in detail. The power supply 13 supplies power to the diamond SAW oscillator 15 and the amplifier 14. The subsequent stage of the diamond SAW oscillator 15 is connected to the previous stage of the amplifier 14. The high frequency signal output from the diamond SAW oscillator 15 is output after being amplified by the amplifier 14. The high frequency signal output from the amplifier 14 becomes a high frequency signal output from the high frequency oscillating unit 11.
In the present embodiment, the high-frequency signal amplified from the high-frequency oscillation unit 11 to a high-frequency output level that excites and emits light emitted from the light-emitting substance enclosed in the discharge lamp 35 (2.45 GHz in this embodiment, the wavelength λ is about 12 cm). ) Is output.

  Next, the waveguide unit 12 will be described in detail. The waveguide unit 12 guides the high-frequency signal output from the high-frequency oscillation unit 11 and emits it as the microwave 10A, and includes a central conductor 30 that radiates the microwave 10A and an isolator 16 as a countermeasure against reflected waves. ing.

The center conductor 30 is a center conductor that radiates microwaves having unidirectionality. The central conductor 30 can radiate a substantially planar microwave 10A.
The isolator 16 is installed behind the amplifier 14 and between the central conductor 30. Therefore, the reflected wave is prevented from returning to the high-frequency oscillator 11 as a result of radiating the microwave 10 </ b> A from the center conductor 30.

In the light source device 1 having the above configuration, the microwave generation unit 10 generates a high-frequency signal and radiates it as a microwave toward the reflector 40. The emitted microwave is a substantially plane wave and is reflected by the inner surface 41 of the reflector 40, and the reflected microwave converges at the center of the discharge lamp 35. The sealed light emitting material is excited (and ionized) by the microwave focused on the discharge lamp 35 and emits plasma, whereby the discharge lamp 35 emits light.
When the discharge lamp 35 emits light, a light beam is emitted. A part of the emitted light beam reaches the reflector 40 and is reflected. These light beams are led out from the opening 42 while being reflected by the inner surface 41 of the reflector 40.

  According to the present embodiment, the free wave end 36 of the discharge lamp 35 and the end part of the discharge lamp 35 that is insulated and fixed to the center conductor 30, that is, the part located at the length L from the free end 36 are respectively standing waves. Becomes the belly of the electric field. And since it becomes a node of the electric field of the standing wave at the center of the space (encapsulation) part 31 of the discharge lamp 35 located at the length L / 2 from the free end 36, the light emitting part 20 of the discharge lamp 35 is connected to the light emitting part 20. The wave power can be input efficiently, and the discharge lamp 35 can emit light efficiently.

  And since the phase shift resulting from plasma generation | occurrence | production arises in the discharge lamp 35, the discharge lamp 35 can be made shorter than a calculated value, and the light source device 1 reduced in size can be obtained. Further, transmission loss is reduced, and light emitted from the discharge lamp 35 can be emitted more efficiently.

Examples of the present embodiment will be described below.
The example employs the value of the length L or the upper limit value and the lower limit value of the range in the light source device 1 of the first embodiment. In the example, λ is an actual wavelength after shortening the wavelength considering the material around the lamp, and in the example, it is 100 mm. Incidentally, the wavelength before shortening the wavelength was 120 mm.

(Example)
Examples of the present embodiment will be described below.
In the embodiment, the length L that is the entire length of the discharge lamp 35 is 35 mm. The length L / 2 from the center of the space (encapsulation) portion 31 of the discharge lamp 35 to the free end 36 of the discharge lamp 35 is 17.5 mm.

  In Comparative Examples 1 to 5, in the above-described light source device, the length L, the length L / 2, the position of the space (encapsulation) part 31, and the presence / absence of connection between the central conductor 30 and the discharge lamp 35 are changed. . Hereinafter, Comparative Examples 1 to 5 will be described while referring to differences from the examples.

(Comparative Example 1)
Below, the comparative example 1 is demonstrated.
In Comparative Example 1, the length L is L = 30 mm.

(Comparative Example 2)
Below, the comparative example 2 is demonstrated.
In Comparative Example 2, the length L is L = 45 mm.

(Comparative Example 3)
Hereinafter, Comparative Example 3 will be described.
In Comparative Example 3, the length L is L = 35 mm.

  Although the comparative example 3 is L = 35 mm similarly to the embodiment, the difference from the embodiment is that the discharge lamp 35 and the central conductor 30 are connected.

(Comparative Example 4)
Hereinafter, Comparative Example 4 will be described.
In Comparative Example 4, L = 35 mm as in the example, but the difference from the example is that the length from the free end 36 is changed to 10 mm instead of L / 2 = 17.5. That is.

(Comparative Example 5)
Hereinafter, Comparative Example 5 will be described.
In Comparative Example 5, the length L is L = 36 mm. And the length from the free end 36 is not L / 2 = 17.5, but is changed to 25 mm.

  Here, it evaluated by measuring the luminance efficiency about the light source device 1 of the above-mentioned Example, and the light source device of Comparative Examples 1-5.

The above evaluation results are shown in Table 1.
The length L from the center of the space (encapsulation) part 31 of the discharge lamp 35 to the free end 36 of the discharge lamp 35 is L = 35 mm, and the center of the space part is located at ½ of the length L of the discharge lamp. In the embodiment in which the center conductor 30 is insulated and fixed from the discharge lamp 35, the luminance efficiency is as high as 70 Lm / W.

  Compared with this, the light source devices of Comparative Examples 1 to 5 have low luminance efficiency, which is less than 60 Lm / W, which is less than 90% of the luminance efficiency of the example, and is not practical. In particular, the light source device 1 of the example has sufficient luminance efficiency to be employed in the projector as the projection display device of the second embodiment described later, and the light source devices of Comparative Examples 1 to 5 have low luminance efficiency. Not practical.

  Thereby, it has confirmed that there existed the above-mentioned effect.

(Modification)
Next, as a modification of the first embodiment, a modification in which an optical member is provided in the reflector of the light source device will be described. In this modified example, the configuration is the same as that of the first embodiment except for the optical member, and the same reference numerals are given and description thereof is omitted.
FIG. 3 is a schematic cross-sectional view illustrating a configuration of a light source device according to a modification.

As shown in FIG. 3A, the light source device 4 includes optical lenses 61 and 62 in the vicinity of the opening of the reflector 40. The optical lenses 61 and 62 are fixed inside the reflector 40 with a heat-resistant adhesive or the like.
The optical lens 61 is a convex lens, and the optical lens 62 is a concave lens. By combining these lenses, the light beam is condensed or converted into parallel light. The combination of lenses is not limited to this modified example, and can be appropriately changed and combined according to the purpose of use.

  As described above, by providing the reflector 40 with the optical lenses 61 and 62, the light guide distance from the discharge lamp 35 as the light source to the optical lenses 61 and 62 can be shortened, so that the light use efficiency is improved. Further, the light beam can be condensed or collimated at the exit of the light beam, increasing the degree of freedom in optical design.

As another modification, a light source device 5 in which an optical lens unit 70 is attached to the tip of a reflector 40 as illustrated in FIG.
In the optical lens unit 70, optical lenses 71 and 72 are fixed to a cylindrical lens housing 73. The optical lenses 71 and 72 are fixed to the lens housing 73 with an adhesive having heat resistance. Further, a screw is formed at the engaging portion between the lens housing 73 and the reflector 40, so that the optical lens unit 70 can move along the optical axis P.

  As described above, since the optical lens unit 70 is mounted on the reflector 40, if a plurality of optical lens units corresponding to the purpose are prepared, a single light source device can support a plurality of uses.

(Second Embodiment)
Next, a projector as a projection display device that employs the light source device described above will be described with reference to the drawings.
FIG. 4 is a block diagram illustrating a schematic configuration of the projector according to the second embodiment.
The projector 100 includes the light source device 1 and the optical system 110 described above.
The optical system 110 includes an illumination optical system 120, a light modulation unit 130, a color synthesis optical system 140, and a projection unit 150. The light source device 1 includes a microwave generation unit 10 and a light emitting unit 20.

  Next, the operation of the projector 100 will be described. Microwaves are emitted from the microwave generation unit 10, and the light emitting unit 20 emits light by the microwaves emitted from the microwave generation unit 10. Moreover, the illumination optical system 120 equalizes the illuminance of the light beam emitted from the light source device 1 and separates it into each color light.

  The light modulation unit 130 modulates the luminous flux of each color light separated by the illumination optical system 120 according to image information to form an optical image. The color synthesis optical system 140 synthesizes the optical images of the respective color lights separated by the illumination optical system 120 and modulated by the light modulation unit 130, and the projection unit 150 projects the optical image.

  The discharge lamp 35 mounted on the projector 100 is a lamp that uses microwaves. Compared with a projector equipped with a conventional illumination device using a discharge lamp, the light source device 1 has a longer life and the light source device is replaced. Can be reduced and the economic effect can be improved.

  Further, by adopting the light source device 1 described above, it is possible to provide the projector 100 in which the utilization efficiency of the light emitted from the discharge lamp 35 is improved.

  DESCRIPTION OF SYMBOLS 1,4,5 ... Light source device, 10 ... Microwave generation part, 10A ... Microwave, 11 ... High frequency oscillation part, 12 ... Waveguide part, 13 ... Power supply, 14 ... Amplifier, 15 ... Diamond SAW oscillator, 16 ... Isolator , 20 ... light emitting part, 30 ... central conductor, 31 ... space part, 32 ... quartz tube, 34 ... conductor, 35 ... discharge lamp, 40 ... reflector, 41 ... inner surface, 42 ... opening, 50 ... coaxial tube, 52 ... Connector part 53 ... Insulating member 56 ... Outer tube as outer part 61, 62 ... Optical lens as optical member, 70 ... Optical lens unit, 71, 72 ... Optical lens as optical member, 100 ... Projection display Projector as device 110 ... optical system 120 ... illumination optical system 130 ... light modulation unit 140 ... color synthesis optical system 150 ... projection unit P ... optical axis λ ... wavelength of microwave, ... length.

Claims (6)

A microwave generator for generating microwaves;
A central conductor connected to the microwave generator and radiating the microwave;
A discharge lamp that is insulated and fixed to the central conductor and discharge-lighted by the microwave;
A reflector formed of a conductive material surrounding the discharge lamp and having one end opened;
A space part in which a luminescent material is enclosed in the discharge lamp,
The light source device characterized in that the center of the space portion is located at a half of the length L of the discharge lamp. The light source device according to claim 1,
The light source device characterized in that the length L of the discharge lamp is less than λ / 2.   3. The light source device according to claim 1, wherein a high-frequency transmission mode transmitted from the microwave generation unit is a TEM (Transverse Electro Magnetic) mode. In the light source device according to any one of claims 1 to 3,
The light source device characterized in that the reflector or an inner surface of the reflector is a metal. In the light source device according to any one of claims 1 to 4,
The light source device, wherein the reflector includes an optical member that efficiently collects or polarizes light on an optical axis of a light beam emitted from the discharge lamp. A microwave generator for generating microwaves;
A central conductor connected to the microwave generator and radiating the microwave;
A discharge lamp that is insulated and fixed to the central conductor and discharge-lighted by the microwave;
A reflector formed of a conductive material surrounding the discharge lamp and having one end opened;
A space part in which a luminescent material is enclosed in the discharge lamp,
A light source device in which a center of the space portion is located at a half of a length L of the discharge lamp;
A light modulator that modulates the light beam emitted from the light source device according to input image information to form an optical image;
And a projection unit that projects an optical image formed by the light modulation unit.

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