Light source device and projector with improved airflow

A light source device, includes: an arc tube which has a light emission portion containing a pair of electrodes disposed along an illumination axis, and a pair of sealing portions extending from both sides of the light emission portion; a reflector which has a reflection portion disposed in the vicinity of one of the sealing portions (the one sealing portion) of the arc tube for reflecting light emitted from the arc tube toward an illumination area; and a rectifying portion disposed between the light emission portion and the reflector for regulating a flow direction of cooling air and transmitting the light from the arc tube.

BACKGROUND

1. Technical Field

The present invention relates to a light source device and a projector including the light source device.

2. Related Art

A projector which forms a light image by modulating light emitted from a light source device and projects the formed light image on a screen or the like is known. The light source device contained in the projector includes an arc tube and a reflector for reflecting light emitted from the arc tube. The arc tube has a light emission portion containing a pair of electrodes, and sealing portions extending from both sides of the light emission portion. A type of the light source device included in the projector has a sub mirror on the arc tube to use light emitted from the arc tube with high efficiency. According to this type of light source device, heat generated by light emission needs to be cooled so as to adjust the temperature of the arc tube to an appropriate temperature.

FIG. 9is a cross-sectional view illustrating the side of a light source unit including a light source device in related art. As described above, a light source device69in the related art includes an arc tube having a light emission portion81and sealing portions82and83, a reflector70, a sub mirror90and other parts. A light source unit8includes the light source device69, a concave lens11for collimating light emitted from the light source device69, a housing9for accommodating the light source device69and the concave lens11, and other components. The housing9has an air intake port9athrough which cooling air W is introduced, and an air discharge port9bthrough which the cooling air W flowing within the housing9is discharged from the housing9. Furthermore, a cooling fan511for delivering the cooling air W, a duct521for guiding the cooling air W toward the air intake port9a, a louver531for controlling the flowing direction of the cooling air W to be introduced from the air intake port9ainto the housing9, and others are provided outside the light source unit8(inside the projector including the light source unit8). Heat generated by light emission from the arc tube80is cooled by the light source unit8, the cooling fan511and others.

According to a technology disclosed in JP-A-2008-216727, a rectifying portion is disposed around the sealing portions of the light source device described above at a position out of the effective optical path particularly for preventing excessive increase in the temperature of the upper area of the arc tube by cooling the light emission portion with high efficiency.

However, when cooling air is supplied to the light source unit8in the related art to cool the heat generated by the arc tube80of the light source device69, the cooling air W tends to flow along the inner surface of the reflector70(a reflection layer73) as indicated by arrows inFIG. 9. In this case, the speed of airflow between the light emission portion81and the reflector70(the reflection layer73) in the direction of an illumination axis L increases. As a result, the flow of the introduced cooling air W to an area A in the upper region of the light emission portion81as an area having a high temperature due to heat convection is limited, and thus the area A cannot be efficiently cooled. When the airflow amount or the airflow speed of the cooling fan511is raised so as to adjust the temperature of the area A in the upper region of the light emission portion81having the high temperature to an appropriate temperature, an area B on the reflector70side of the light emission portion81is excessively cooled. In this case, the temperature difference in the temperature distribution in the direction of the illumination axis L increases. Particularly, in case of the light source device including the sub mirror90and thus having a relatively larger distance between the light emission portion81and the reflector70in the direction of the illumination axis L than the distance of a light source device not including the sub mirror90, the temperature difference becomes more remarkable.

When the excessively cooled condition continues in the area B, the inner wall in the area B of the light emission portion81is blackened. When the air supply is decreased so as to prevent excessive cooling in the area B, the temperature of the area A is raised to a high temperature. As a result, the inner wall in the area A of the light emission portion81is easily whitened. The blackening refers to a phenomenon where evaporated atoms of a base material constituting an electrode (such as tungsten atoms) do not return to the electrode but adhere to the inner wall of the light emission portion81when a halogen cycle of the base material is not normally performed due to the low temperature. The whitening herein refers to a phenomenon which whitens a base material constituting the light emission portion81at the time of recrystallization of the base material caused by the high temperature. When the whitening or blackening is produced, the area corresponding to the whitening or blackening loses transparency in either of the cases and lowers the amount of light emitted from the light source device69.

Therefore, such a light source device and a projector have been demanded which can efficiently cool generated heat, properly control the temperatures of the upper area of the light emission portion and the reflector side of the light emission portion, reduce the temperature difference on the light emission portion, and obtain uniform temperature distribution in the direction of the illumination axis.

SUMMARY

It is an advantage of some aspects of the invention to provide a technology for solving at least a part of the problems described above.

First Aspect

A first aspect of the invention is directed to a light source device which includes: (a) an arc tube which has a light emission portion containing a pair of electrodes disposed along an illumination axis, and a pair of sealing portions extending from both sides of the light emission portion; (b) a reflector which has a reflection portion disposed in the vicinity of one of the sealing portions (the one sealing portion) of the arc tube for reflecting light emitted from the arc tube toward an illumination area; and (c) a rectifying portion disposed between the light emission portion and the reflector for regulating a flow direction of cooling air and transmitting the light from the arc tube.

According to the light source device having this structure, cooling air introduced by the rectifying portion disposed between the light emission portion and the reflector to flow along the reflection portion of the reflector flows along the rectifying portion by the function of the rectifying portion for regulating the flow direction. Since the rectifying portion transmits light emitted from the arc tube and further transmits light reflected by the reflection portion, the light amount from the light source device becomes similar to that from a light source device in related art. In this case, the cooling air easily flows to the upper area of the light emission portion as an area having high temperature, and thus efficiently cools the heat in the upper area of the light emission portion as the area having high temperature. Moreover, even when air is supplied to adjust the temperature of the upper area of the light emission portion to an appropriate temperature, the reflector side of the light emission portion is not excessively cooled. Thus, the upper area of the light emission portion can be efficiently cooled, and the temperatures of the upper area of the light emission portion and the reflector side of the light emission portion can be properly controlled such that the temperature difference between these areas can be reduced. Accordingly, the light source device having uniform temperature distribution in the direction of the illumination axis can be produced.

Second Aspect

A second aspect of the invention is directed to the light source device of the above aspect which further includes a sub mirror disposed in the vicinity of the other sealing portion in such a manner as to cover the outer surface of the light emission portion as the surface facing the illumination area to reflect the light from the arc tube toward the arc tube.

According to the light source device of this aspect including the sub mirror, the temperature of the upper area of the light emission portion increases higher than that of a light source device having no sub mirror. However, the upper area of the light emission portion can be efficiently cooled by the rectifying portion. Moreover, the temperatures of the upper area of the light emission portion and the reflector side of the light emission portion can be properly controlled. Thus, the temperature difference in the temperature distribution of the light source device can be reduced.

Third Aspect

A third aspect of the invention is directed to the light source device of the above aspects, wherein the rectifying portion is fixed to at least either the one sealing portion or the reflector.

According to the light source device of this aspect, the rectifying portion is fixed to at least either the one sealing portion or the reflector. Thus, the rectifying portion can be operated in a stable manner without affected by the effect of flow of the cooling air.

Fourth Aspect

A fourth aspect of the invention is directed to the light source device of the above aspects which further includes a support portion which supports the rectifying portion in the vicinity of the one sealing portion and fixes the rectifying portion to a position around the one sealing portion.

According to the light source device of this aspect, the rectifying portion is securely fixed to the one sealing portion in a proper position with respect to the reflection portion of the reflector and the arc tube. Moreover, the rectifying portion plate can be operated in a stable manner without affected by the effect of flow of the cooling air.

Fifth Aspect

A fifth aspect of the invention is directed to the light source device of the above aspects, wherein the support portion holds the rectifying portion between the support portion and the light emission portion and fixes the rectifying portion.

According to the light source device of this aspect, the support portion holds the rectifying portion between the support portion and the light emission portion and fixes the rectifying portion. Thus, the rectifying portion can be securely fixed and operated in a stable manner without affected by the effect of flow of the cooling air. Moreover, the effect of thermal stress on the one sealing portion can be reduced by avoiding direct fixture of the rectifying portion to the one sealing portion.

Sixth Aspect

A sixth aspect of the invention is directed to the light source device of the above aspects, wherein a notch is formed on the edge of the rectifying portion.

According to the light source device of this aspect, the cooling air is introduced to an area surrounded by the reflector and the rectifying portion through the notch formed on the edge of the rectifying portion. Thus, the heat within the area can be appropriately cooled.

Seventh Aspect

A seventh aspect of the invention is directed to the light source device of the above aspects, wherein: when an adhesive is used for fixing the rectifying portion to the one sealing portion, the adhesive fixes the rectifying portion to a position corresponding to an area out of an electrode connection region of the one sealing portion.

According to the light source device of this aspect, the adhesive is applied to the position corresponding to the area out of the electrode connection region of the one sealing portion. Thus, the effect on the one sealing portion caused by thermal stress can be reduced by avoiding application of the adhesive to the electrode connection region easily affected by thermal stress.

The electrode connection region herein refers to an area where lines contained in the electrode are connected by welding or the like with a metal foil or the like sealed within the sealing portion. The area out of the electrode connection region refers to an area not corresponding to the electrode connection region.

Eighth Aspect

An eighth aspect of the invention is directed to the light source device of the above aspects, wherein the rectifying portion is disposed in such a position as to be substantially orthogonal to the illumination axis.

According to the light source device of this aspect, the rectifying portion is disposed substantially orthogonal to the illumination axis. Thus, even when the condition of the light source device is switched from the normal condition to the suspension condition to use the light source device upside down, the difference between the position of the rectifying portion in the upside-down condition and that position in the normal condition is small. Accordingly, advantages similar to those provided in the normal condition can be offered in the upside-down condition.

Ninth Aspect

A ninth aspect of the invention is directed to the light source device of the above aspects, wherein the rectifying portion has a flat surface or a curved surface through which the light can be transmitted.

According to the light source device of this aspect, the rectifying portion has a flat surface or a curved surface. Thus, highly efficient surfaces of the rectifying portion suited for the respective shapes of the arc tube, the reflector and the like included in the light source device and for the respective ways of flow of the cooling air can be selected with a higher degree of freedom.

Tenth Aspect

A tenth aspect of the invention is directed to the light source device of the above aspects, wherein the rectifying portion has a substantially circular or substantially rectangular flat shape.

According to the light source device of this aspect, the shape of the rectifying portion can be matched with the inner surface shape of the reflection portion when the flat surface shape of the rectifying portion is substantially circular. In this case, the flow of the cooling air can be securely regulated. When the flat surface shape is substantially rectangular, a clearance is produced by the difference between the inner surface shape of the reflection portion and the rectangular shape of the rectifying portion. Thus, the cooling air can be introduced into the area surrounded by the reflection portion and the rectifying portion through the clearance.

Eleventh Aspect

An eleventh aspect of the invention is directed to the light source device of the above aspects, wherein anti-reflection processing is applied to the surface of the rectifying portion.

According to the light source device of this aspect, anti-refection processing is applied to the surface of the rectifying portion. Thus, light emitted from the light emission portion and light reflected by the reflection portion are prevented from being changed in their optical paths due to reflection by the rectifying portion when the lights are passing through the rectifying portion. Accordingly, the efficiency of extracting the light emitted from the light emission portion to the outside of the light source device can be improved.

Twelfth Aspect

A twelfth aspect of the invention is directed to a projector which includes; the light source device of any aspects described above; and an optical modulation device which forms an optical image by modulating light emitted from the light source device according to an image signal.

The projector of this aspect of the invention includes the light source device of any aspects. In this case, the projector can efficiently cool the upper area of the light emission portion, and properly control the temperatures of the upper area of the light emission portion and the reflector side of the light emission portion such that the temperature difference between these areas can be reduced. Thus, the temperature distribution in the direction of the illumination axis becomes uniform, and whitening and blackening of the light emission portion can be reduced. Accordingly, the life of the light source device included in the projector can be increased.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The exemplary embodiments according to the invention are hereinafter described with reference to the drawings.

First Embodiment

FIG. 1illustrates optical systems of a projector according to a first embodiment. The structure and operation of the optical systems of a projector600are now explained with reference toFIG. 1.

In the figures for explaining this embodiment (FIG. 1andFIGS. 2A and 2Breferred to in the following description), an XYZ orthogonal coordinate system is used which indicates an X axis direction as a direction of an illumination axis L of light emitted from a light source device61toward an illumination area, a Y axis direction as a direction orthogonal to the X axis direction and in parallel with the sheet surface ofFIG. 1, and a Z axis direction as a direction orthogonal to the X axis direction and perpendicular to the sheet surface ofFIG. 1. In this case, the light traveling direction corresponds to the +X direction, the left direction with respect to the +X direction corresponds to the +Y direction, and the upper direction with respect to the +X direction corresponds to the +Z direction.

The projector600according to this embodiment has optical systems. The optical systems form an optical image by modulating light emitted from the light source device61according to image signals, and project a projection image to a projection target surface such as a screen S through a projection system50.

As illustrated inFIG. 1, the optical systems of the projector600include an integrator illumination system10, a color separation and light guide system20, an optical modulation device, a color combining system, and the projection system50. The integrator illumination system10is an optical system for equalizing illuminance of light emitted from the light source device61within a plane orthogonal to the illumination axis L. The color separation and light guide system20separates illumination light received from the integrator illumination system10into three color lights in red (R), green (G), and blue (B), and guides the divided color lights to the illumination area.

The optical modulation device is an optical system which modulates each of the three color lights separated by the color separation and light guide system20according to image signals, and includes three liquid crystal devices30R,30G, and30B corresponding to the three color lights in red (R), green (G), and blue (B). The color combining system combines optical images modulated by the optical modulation device (the three liquid crystal devices30R,30G, and30B), and includes a cross dichroic prism40. The projection system50is an optical system which projects an optical image produced by combining the optical images in the respective colors using the color combining system (the cross dichroic prism40) to the projection target surface such as the screen S.

The integrator illumination system10includes the light source device61for emitting illumination light toward the illumination area, a concave lens11for releasing converged light emitted from the light source device61as substantially parallel light, and a first lens array12having a plurality of first small lenses12afor dividing the illumination light released from the concave lens11into a plurality of partial lights.

The integrator illumination system10further includes a second lens array13having a plurality of second small lenses13acorresponding to the plural first small lenses12aof the first lens array12, a polarization converting element14which converts the partial lights released from the second lens array13into substantially one type of linear polarized lights having the same polarization direction and releases the converted lights, and a stacking lens15for stacking the respective partial lights released from the polarization converting element14on the illumination area.

As illustrated inFIG. 1(andFIGS. 2A and 2Bas well), the light source device61includes a reflector70, an arc tube80having the light emission center in the vicinity of a first focus of the reflector70, a sub mirror90for reflecting light emitted from a light emission portion81, and a rectifying portion100for regulating the flow direction of cooling air W1. The light source device61emits light having the illumination axis L as the center axis.

The details of the structure and operation of the light source device61will be described after the explanation of the optical systems of the projector600.

As illustrated inFIG. 1, the concave lens11is disposed on the illumination area of the reflector70. The concave lens11is so designed as to direct the light from the reflector70toward the first lens array12.

The first lens array12functions as a light dividing optical element for dividing light from the concave lens11into plural partial lights, and has the plural first small lenses12adisposed in matrix having plural lines and plural rows within a plane orthogonal to the illumination axis L. Each external shape of the first small lenses12ais similar to each external shape of the image forming areas of the liquid crystal devices30R,30G, and30B.

The second lens array13forms respective images of the first small lenses12aof the first lens array12in the vicinity of the image forming areas of the liquid crystal devices30R,30G, and303in cooperation with the stacking lens15. The second lens array13has a structure substantially similar to that of the first lens array12, containing the plural second small lenses13adisposed in matrix having plural lines and plural rows within a plane orthogonal to the illumination axis L.

The polarization converting element14is a polarizing element which converts the respective partial lights divided by the first lens array12into substantially one type of linear polarized lights having the same polarization direction and releases the converted lights. The polarization converting element14has a polarization dividing layer which transmits one of the linear polarized light components of the polarized light components contained in the light emitted from the light source device61and reflects the other linear polarized light component in a direction perpendicular to the illumination axis L, a reflection layer which reflects the other linear polarized light component reflected by the polarization dividing layer in a direction parallel with the illumination axis L, and a retardation film which converts the one linear polarized light component transmitted by the polarization dividing layer into the other linear polarized light component.

The stacking lens15is an optical element which collects the plural partial lights having passed the first lens array12, the second lens array13, and the polarization converting element14and stacks the collected partial lights in the vicinity of the image forming areas of the liquid crystal devices30R,30G, and30B. The stacking lens15is disposed in such a position that the optical axis of the stacking lens15almost coincides with the illumination axis L of the integrator illumination system10. The stacking lens15may be a compound lens produced by combining plural lenses.

The color separation and light guide system20has dichroic mirrors21and22, reflection mirrors23,24, and25, an entrance side lens26, a relay lens27, and converging lenses28R,28G, and28B. The color separation and light guide system20separates the illumination light released from the stacking lens15into three color lights of red light, green light, and blue light, and guides the respective color lights to the three liquid crystal devices30R,30G, and30B as the illumination targets.

The liquid crystal devices30R,30G, and30B which modulate illumination lights according to image signals are the illumination targets of the integrator illumination system10. Each of the liquid crystal devices30R,30G, and30B has liquid crystals as electro-optic substances sealed between a pair of transparent glass base materials, and modulates the polarization direction of the one type of the linear polarized lights released from entrance side polarization plates described later according to inputted image signals by using polysilicon TFT as switching elements, for example.

The converging lenses28R,28G, and28B for controlling the incident angles are disposed on the optical path before the liquid crystal devices30R,30G, and30B. Though not shown in the figure, the entrance side polarization plates are interposed between the converging lens28R and the liquid crystal device30R, between the converging lens28G and the liquid crystal device30G, and between the converging lens28B and the liquid crystal device30B, and exit side polarization plates are interposed between the liquid crystal device30R and the cross dichroic prism40, between the liquid crystal device30G and the cross dichroic prism40, and between the liquid crystal device30B and the cross dichroic prism40. The respective entering color lights are modulated by the entrance side polarization plates, the liquid crystal devices30R,30G, and30B, and the exit side polarization plates.

The cross dichroic prism40is an optical device which combines the optical images emitted from the exit side polarization plates and modulated for each color light into a color image. The cross dichroic prism40has a substantially square shape in the plan view produced by affixing four rectangular prisms, and dielectric multilayer films are provided on the interfaces of the rectangular prisms affixed to one another in an approximately X shape. The dielectric multilayer film formed on one of the interfaces in the substantially X shape reflects the red light, and the dielectric multilayer film formed on the other interface reflects the blue light. The red light and the blue light are bent by the dielectric multilayer films in the same direction as the traveling direction of the green light such that the three color lights can be combined.

The color image released from the cross dichroic prism40is expanded and projected by the projection system50to form a projection image on the screen S as the projection target surface.

FIGS. 2A and 2Billustrate a light source unit.FIG. 2Ais a cross-sectional view showing the side of the light source unit.FIG. 2Bis a front view showing a connecting area between the light emission portion and one of the sealing portions as viewed from the reflector side, the connecting area containing a condition cut along a plane orthogonal to the illumination axis. The structure and operation of a light source unit1are now described with reference toFIGS. 2A and 2B.

The light source unit1in this embodiment includes the light source device61, the concave lens11, and the housing9for accommodating the light source device61and the concave lens11. A cooling mechanism500for cooling heat generated by the light source device61is further provided in such a position as to face the light source unit1when the light source unit1is accommodated at a predetermined position inside the projector600.

As illustrated inFIG. 2A, the light source device61includes the reflector70, the arc tube80having the light emission center in the vicinity of the first focus of the reflector70, and the sub mirror90for reflecting light emitted from the light emission portion81, and the rectifying portion100for regulating the flow direction of the cooling air W1introduced into the light source device61. The light source device61emits light having the illumination axis L as the center axis.

The reflector70includes a reflector main body71having ellipsoidal concave surfaces71aand71b, and a cylindrical portion72through which an end of a sealing portion (one of sealing portions)82of the arc tube80described later is inserted to be fixed to the cylindrical portion72. The reflector main body71and the cylindrical portion72constituting the reflector70are formed integrally with each other. A reflection layer73(73aand73b) having high reflectance are provided on the concave surfaces71aand71bof the reflector main body71. The details of the concave surfaces71aand71band the reflection layer73(73aand73b) corresponding to the concave surfaces71aand71bwill be described later.

The cylindrical portion72is a cylindrical body provided on the surface opposite to the reflection layer73in such a manner as to extend from the centers of the reflection layer73and the reflector main body71. An opening72ais formed inside the cylindrical portion72such that the end of the sealing portion82of the arc tube80described later can be inserted through the opening72aand fixed thereto. The arc tube80described later is fixed to the cylindrical portion72of the reflector70by inserting the end of the sealing portion through the opening72aand filling the clearance between the opening72aand the sealing portion82with an inorganic adhesive C such as cement.

Preferable examples of the base material for constituting the reflector70(the reflector main body71and the cylindrical portion72) are crystallized glass and alumina (Al2O3). The reflection layer73is formed by dielectric multilayer film made of titanium oxide (TiO2) and silicon oxide (SiO2).

As illustrated inFIGS. 2A and 2B, the arc tube includes the light emission portion81having a spherical shape, and a pair of the columnar sealing portions82and83extending from both sides of the light emission portion81along the illumination axis L. The arc tube80has a pair of electrodes84and85contained in the light emission portion81and disposed close to and opposed to each other along the illumination axis L, a pair of metal foils86and87sealed within the pair of the sealing portions82and83, respectively, and a pair of leads88and89electrically connected with the metal foils86and87, respectively.

The conditions and the like of the elements included in the arc tube80are as follows, for example. The light emission portion81and the sealing portions82and83are made of quartz glass or the like, and mercury, rare gas, and a small amount of metal halogenated material are sealed into the light emission portion81. The electrodes84and85are tungsten electrodes or the like, and the metal foils86and87are molybdenum foils or the like. The leads88and89are made of molybdenum or tungsten, for example. The arc tube80can be formed by various types of arc tube capable of emitting light having high luminance, such as a high-pressure mercury lamp, an extra-high pressure mercury lamp, and a metal halide lamp.

The sub mirror90covering approximately the half of the light emission portion81is a component disposed opposed to the concave surfaces71aand71bof the reflector70to reflect light emitted toward the illumination area from the arc tube80again toward the arc tube80. The sub mirror90includes a sub mirror main body91having a concave surface91a, and a cylindrical portion92having an opening92athrough which the sealing portion (the other sealing portion)83of the arc tube80is inserted to be fixed to the opening92a. The sub mirror main body91and the cylindrical portion92constituting the sub mirror90are formed integrally with each other. A reflection layer93having high reflectance is formed on the concave surface91aof the sub mirror main body91. The light emitted from the arc tube80and reflected by the reflection layer93toward the arc tube80passes through the arc tube80and reaches the reflector70.

The material for constituting the sub mirror90(the sub mirror main body91and the cylindrical portion92) is quartz glass, for example. The reflection layer is formed by dielectric multilayer film made of tantalum oxide (Ta2O3) and silicon oxide (SiO2), for example.

The sub mirror90having this structure is fixed to the sealing portion83of the arc tube80by inserting the sealing portion83of the arc tube80through the opening92aof the cylindrical portion92and filling the clearance between the opening portion92aof the cylindrical portion92and the sealing portion83with the inorganic adhesive C such as cement.

The rectifying portion100is disposed between the one sealing portion82and the reflector70to regulate the flow direction of the cooling air W1introduced into the light source device61. The rectifying portion100transmits light emitted from the arc tube80toward the reflection layer73of the reflector70, and further transmits light in the opposite direction reflected by the reflection layer73toward the illumination area. In this embodiment, the rectifying portion100has a disk-shaped rectifying portion main body101as illustrated inFIG. 2B. The rectifying portion100further has an opening101aat the center.

A support member110as a support portion is a component for supporting the rectifying portion100on the one sealing portion82and fixing the rectifying portion100to the one sealing portion82. The support member110includes a disk-shaped support portion main body111, and a flange112formed on the periphery of the support portion main body111. An opening111ais formed inside the support portion main body111.

According to this embodiment, the rectifying portion100is formed integrally with the support member110by inserting the support portion main body111through the opening101aof the rectifying portion main body101and bringing the rectifying portion100into contact with the surface of the flange112, and then heating the rectifying portion100. The rectifying portion100thus formed is fixed to the sealing portion82by inserting the sealing portion82of the arc tube80through the opening111aof the support portion main body111and filling the clearance between the sealing portion and the opening111aof the support member110with the inorganic adhesive C such as cement. In this condition, substantially no clearance is produced between an outer circumferential end101bof the rectifying portion100and the reflection layer73in this embodiment.

The rectifying portion100fixed to the sealing portion82via the support member110is disposed in such a position as to be substantially orthogonal to the illumination axis L in this embodiment. The rectifying portion main body101has a flat surface to which anti-reflection processing is applied. The materials for constituting the rectifying portion100and the support member110are quartz glass, for example. Alternatively, low thermal expansion glass such as neoceram (registered trademark) and high heat conductive material such as sapphire may be used.

The reflection layer73(73b) of the reflector70receiving the light transmitted through the rectifying portion100has a shape withdrawn from the reflection layer73(73a) of the reflector70receiving light not transmitted through the rectifying portion100. The reflection layer73bcorresponds to the concave surface71b, and the reflection layer73acorresponds to the concave surface71a. The light transmitted through the rectifying portion100has a longer optical path length than that of the light not transmitted through the rectifying portion100. Thus, the optical path length of the light transmitted through the rectifying portion100is corrected by the structure of the reflection layer73(73b).

The housing9made of resin having high heat resistance or the like fixes the reflector70and the concave lens11. The housing9isolates a space C1formed between the reflector70(and the rectifying portion100) and the concave lens11from the surroundings to prevent leakage of unnecessary light emitted from the arc tube80to the outside as stray light. An air intake port9ais formed on the upper wall surface of the housing9in the +Z direction as the side surface of the housing9. Also, an air discharge port9bis formed on the lower wall surface of the housing9in the −Z, direction. Air for cooling (cooling air) is introduced from the outside through the air intake port9a, and air after cooling is discharged through the air discharge port9b.

The cooling mechanism500is a cooling device which cools heat generated by light emission from the light emission portion81of the arc tube80in cooperation with the air intake port9a, the air discharge port9band the like. The cooling mechanism500includes a cooling fan510for delivering cooling air, a duct520for introducing the generated cooling air to the air intake port9aof the housing9, a louver530for controlling the flow direction of the cooling air flowing through the air intake port9atoward the space C1of the housing9(the space C1of the light source unit1), and other parts. A discharge duct (not shown) is further provided inside the projector600in such a position as to face the air discharge port9b. The heated cooling air passing through the air discharge port9bis discharged through the discharge duct to the outside of the projector600.

The flow of the cooling air W1(indicated by broken lines with arrows) introduced through the air intake port9ato the space C1of the light source unit1by operation of the cooling mechanism500is now described.

The cooling air W1having the flowing direction regulated by the louver530of the cooling mechanism500is introduced to the space C1of the housing9through the air intake port9a, and flows toward the reflector70. The cooling air W1having reached the reflector70flows along the reflection layer73of the reflector70.

The cooling air W1flowing along the reflection layer73of the reflector70flows in the direction along the flat surface of the rectifying portion100(−Z direction) by the function of the rectifying portion100for regulating the flow direction. Then, the cooling air W1regulated by the rectifying portion100flows from an area A in the upper region of the light emission portion81to an area B on the reflector70side of the light emission portion81. By the flow of the cooling air W1, the area B as well as the area A are cooled. Then, the cooling air W1flows in the direction along the flat surface of the rectifying portion100(−Z direction), and again flows along the reflection layer73away from the rectifying portion100. Finally, the cooling air W1is discharged through the air discharge port9b.

This embodiment provides the following advantages.

(1) According to the light source device61in this embodiment, the cooling air W1introduced to flow along the reflection layer73of the reflector70flows along the rectifying portion100disposed between the light emission portion81and the reflector70by the function of the rectifying portion100for regulating the flow direction. Since the rectifying portion100transmits light emitted from the arc tube80and further transmits light reflected by the reflection layer73, the light amount from the light source device61becomes similar to that from a light source device in related art. In this case, the cooling air W1easily flows to the area A in the upper region of the light emission portion81as an area having high temperature, and also flows to the area B on the reflector70side of the light emission portion81. Thus, the heat on the area. A in the upper region of the light emission portion81as the area having high temperature can be efficiently cooled. Moreover, even when air is supplied to adjust the temperature of the area A in the upper region of the light emission portion81to an appropriate temperature, the area B on the reflector70side of the light emission portion81is not excessively cooled. Thus, the upper area (area A) of the light emission portion81can be efficiently cooled, and the temperatures of the upper area of the light emission portion81(area A) and the reflector70side of the light emission portion81(area B) can be properly controlled such that the temperature difference between the area A and the area B can be reduced. Accordingly, the light source device61having uniform temperature distribution in the direction of the illumination axis L can be produced.

(2) According to the light source device61in this embodiment, the rectifying portion100can be securely fixed to the one sealing portion82in a proper position for the reflection layer73of the reflector70and the arc tube80by using the support member110, and can be operated in a stable condition without affected by the flow of the cooling air W1.

(3) According to the light source device61in this embodiment, the rectifying portion100is disposed substantially orthogonal to the illumination axis L. Thus, even when the condition of the light source device61is switched from the normal condition to the suspension condition to use the light source device61upside down, the difference between the position of the rectifying portion100in the suspension condition and that position in the normal condition is small. Accordingly, the above advantages of the rectifying portion100can be offered in the suspension condition similarly to the normal condition. In this case, an air discharge port (not shown) on the upper wall surface of the housing9in the +Z direction and an air intake port (not shown) on the lower wall in the −Z direction are added. Also, the duct520of the cooling mechanism500is branched in two directions and connected to the air intake ports in the +Z direction and the −Z direction. In addition, a switching unit (not shown) for switching such that the cooling air W1can always flow toward the air intake port positioned at the upper position in the direction of gravity at the time of switching the position is provided to use the light source device61both in the normal condition and the suspension condition.

(4) According to the light source device61in this embodiment, the rectifying portion100has a flat surface. Thus, the rectifying portion100can be manufactured at low manufacturing cost by forming the rectifying portion100from a plate-shaped material.

(5) According to the light source device61in this embodiment, the rectifying portion100has a substantially circular flat shape. Thus, the shape of the rectifying portion100can be matched with the inner surface shape of the reflection layer73. Accordingly, the flow of the cooling air W1can be securely regulated.

(6) According to the light source device61in this embodiment, anti-refection processing is applied to the surface of the rectifying portion100. Thus, light emitted from the light emission portion81and light reflected by the reflection layer73are prevented from being changed in their optical paths due to reflection by the rectifying portion100when the lights are passing through the rectifying portion100. Accordingly, the efficiency of extracting the light emitted from the light emission portion81to the outside of the light source device61can be improved.

(7) According to the light source device61in this embodiment, the upper area of the light emission portion81(area A) can be efficiently cooled, and the temperatures of the upper area of the light emission portion81and the reflector70side of the light emission portion81can be properly controlled such that the temperature difference between the area A and the area B can be reduced. Thus, the temperature distribution in the direction of the illumination axis L becomes uniform, and whitening and blackening of the light emission portion81can be reduced. Accordingly, problems such as lowering of the light amount caused by loss of transparency of the light emission portion81and corruption of the light emission portion81caused by development of whitening or blackening can be prevented, and the life of the light source device61can be increased.

(8) According to the light source device61in this embodiment capable of providing the above advantages, the number of revolutions of the cooling fan510can be made smaller than that of a cooling fan in related art. Thus, the noise of the projector600can be reduced. Moreover, the power consumption of the cooling fan510during operation can be decreased.

(9) According to this embodiment, the projector600includes the light source device61having a long life. When the light source device61having a long life is incorporated in the projector600or other apparatus, the number of times for replacing the light source device61is lowered. Thus, the amount of produced industrial waste can be reduced.

Second Embodiment

FIGS. 3A and 3Billustrate a light source unit according to a second embodiment.FIG. 3Ais a cross-sectional view showing the side of the light source unit.FIG. 3Bis a front view showing a connecting area between the light emission portion and one of the sealing portions as viewed from the reflector side, the connecting area containing a condition cut along a plane orthogonal to the illumination axis. A rectifying portion120inFIG. 3Ais shown as a cross section taken along a line A-A inFIG. 3Bfor simplifying the explanation. InFIGS. 3A and 3B, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIGS. 3A and 3Bis similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the second embodiment is similar to the projector600in the first embodiment except for that a light source unit2is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit2in the second embodiment are now described with reference toFIGS. 3A and 3B.

The light source unit2in the second embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the second embodiment, the rectifying portion120included in a light source device62is different from the rectifying portion100included in the light source device61in the first embodiment. In the second embodiment, no support portion such as the support member110in the first embodiment is used. The rectifying portion120in the second embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment, and performs operation similar to that of the rectifying portion100in the first embodiment.

In the second embodiment, the rectifying portion120includes a disk-shaped rectifying portion main body121having a flat surface as illustrated inFIG. 3B. The rectifying portion120further has four notches122formed on the edge of the rectifying portion main body121at equal intervals, and four fixing portions123as the remaining edges after removal of the notches122to provide portions to be fixed to the reflector70. An opening121ais further formed at the center of the rectifying portion main body121.

The rectifying portion120is produced by inserting the sealing portion82of the arc tube80through the opening121a, and bringing the fixing portions123of the rectifying portion120into contact with the reflection layer73in a direction substantially orthogonal to the illumination axis L. Then, the ends of the four fixing portions123contacting the reflection layer73are fixed to the reflection layer73by the inorganic adhesive C such as cement. The opening121aof the rectifying portion120is positioned away from the outer circumferential surface of the sealing portion82of the arc tube80. Anti-reflection processing is applied to the surface of the rectifying portion120similarly to the first embodiment, and the material constituting the rectifying portion120is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W2(indicated by broken lines with arrows) introduced through the air intake port9ato a space C2of the light source unit2by operation of the cooling mechanism500is now explained.

The cooling air W2having the flowing direction regulated by the louver530of the cooling mechanism500flows to the space C2of the housing9through the air intake port9a, and flows toward the reflector70. The cooling air W2having reached the reflector70flows along the reflection layer73of the reflector70.

The flow direction of the cooling air W2flowing along the reflection layer73of the reflector70is regulated by the rectifying portion120. More specifically, a part of the cooling air W2flowing along the reflection layer73flows toward a space D2surrounded by the reflector70and the rectifying portion120via the notch122of the rectifying portion120positioned in the +Z direction. Most of the remaining cooling air W2flows in the direction along the flat surface of the rectifying portion120(−Z direction).

The cooling air W2flowing in the direction along the flat surface of the rectifying portion120(−Z direction) flows from the area A in the upper region of the light emission portion81to the area B on the reflector70side of the light emission portion81. By the flow of the cooling air W2, the area B as well as the area A are cooled. Then, the cooling air W2flows in the direction along the flat surface of the rectifying portion120(−Z direction), and again flows along the reflection layer73away from the rectifying portion120. Finally, the cooling air W2is discharged through the air discharge port9b.

On the other hand, the cooling air W2introduced to the space D2surrounded by the reflector70and the rectifying portion120cools the space D2, and again flows out through the notch122positioned in the −Z direction and moves along the reflection layer73. Then, the cooling air W2is discharged through the air discharge port9b.

The light source unit2according to this embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that the support portion is not included and that different structure and fixing method of the rectifying portion120of the light source device62are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device62in the second embodiment, the notches122are formed on the edge of the rectifying portion120. Thus, the cooling air W2can be introduced through the notches122to the space D2surrounded by the reflector70and the rectifying portion120. Accordingly, the heat in the space D2can be properly cooled.

(2) According to the light source device62in the second embodiment, the rectifying portion120is fixed to the reflection layer73of the reflector70. Thus, the effect on the sealing portion82caused by thermal stress produced when the rectifying portion120is fixed to the sealing portion82can be reduced.

Third Embodiment

FIG. 4is a cross-sectional view illustrating the side of a light source unit according to a third embodiment. InFIG. 4, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIG. 4is similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the third embodiment is similar to the projector600in the first embodiment except for that a light source unit3is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit3in the third embodiment are now described with reference toFIG. 4.

The light source unit3in the third embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the third embodiment, a rectifying portion130included in a light source device63and a support member140fixing the rectifying portion130are different from the rectifying portion100and the support member110included in the light source device61in the first embodiment. The rectifying portion130in the third embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment and performs operation similar to that of the rectifying portion100in the first embodiment.

In the third embodiment, the rectifying portion130includes a disk-shaped rectifying portion main body131having a flat surface as illustrated inFIG. 4. An opening131ais further formed at the center of the rectifying portion main body131.

The support member140as the support portion in this embodiment includes a cylindrical support portion main body141, and a flange142formed on the periphery of the support portion main body141. In this embodiment, the rectifying portion130is produced by inserting the sealing portion82through the opening131aof the rectifying portion main body131, and further through the inner surface of the support portion main body141of the support member140. Then, the support member140is shifted along the outer surface of the sealing portion82toward the light emission portion81, and the rectifying portion130is pressed against the surface of the flange142of the support member140and brought into contact with the light emission portion81. By this method, the rectifying portion130is sandwiched between the outer surface of the light emission portion81and the flange142of the support member140to be fixed therebetween.

The support member140is formed by a pipe-shaped metal component, and the support portion main body141has a length sufficient for reaching the inside of the opening72aof the reflector70under the condition in which the rectifying portion130is sandwiched between the light emission portion81and the support member140. Thus, after the rectifying portion130is sandwiched between the light emission portion81and the support portion main body141, the clearance between the opening72aand the ends of the sealing portion82and the support portion main body141inserted through the opening72ais filled with the inorganic adhesive C such as cement to fix the sealing portion82and the support portion main body141.

According to this embodiment, a substantially constant clearance is formed between an outer circumferential end131bof the rectifying portion130and the opposed reflection layer73in this condition. The rectifying portion130sandwiched between the light emission portion81and the support member140and fixed therebetween is disposed substantially orthogonal to the illumination axis L. Anti-reflection processing is applied to the surface of the rectifying portion130similarly to the first embodiment, and the material constituting the rectifying portion130is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W3(indicated by broken lines with arrows) introduced through the air intake port9ato a space C3of the light source unit3by operation of the cooling mechanism500is now explained. The flow of the cooling air W3in this embodiment is substantially similar to the flow of the cooling air W2in the second embodiment.

The cooling air W3flows to the space C3of the housing9through the air intake port9aby the operation of the cooling mechanism500, and moves toward the reflector70. The cooling air W3having reached the reflector70flows along the reflection layer73of the reflector70. A part of the cooling air W3flows toward a space D3surrounded by the reflector70and the rectifying portion130via the clearance between the outer circumferential end131bof the rectifying portion130in the +Z direction and the reflection layer73. Most of the remaining cooling air W3flows in the direction along the flat surface of the rectifying portion130(−Z direction).

The cooling air W3flowing in the direction along the flat surface of the rectifying portion130(−Z direction) flows from the area A in the upper region of the light emission portion81to the area B on the reflector70side of the light emission portion81. By the flow of the cooling air W3, the area B as well as the area A are cooled. Then, the cooling air W3flows in the direction along the flat surface of the rectifying portion130(−Z direction), and again flows along the reflection layer73away from the rectifying portion130. Finally, the cooling air W3is discharged through the air discharge port9b.

On the other hand, the cooling air W3introduced to the space D3surrounded by the reflector70and the rectifying portion130cools the space D3, and again flows out through the clearance between the outer circumferential end131bin the −Z direction and the reflection layer73and moves along the reflection layer73. Then, the cooling air W3is discharged through the air discharge port9b.

The light source unit3according to the third embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that different structure and fixing method of the rectifying portion130of the light source device63and the support member140are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device63in this embodiment, the rectifying portion130is sandwiched between the light emission portion81and the support member140and fixed therebetween. Thus, the rectifying portion130can be securely fixed, and can be operated in a stable condition without affected by the flow of the cooling air W3. Moreover, the effect of thermal stress on the sealing portion82can be reduced by avoiding direct fixture to the sealing portion82by using an adhesive or the like.

Fourth Embodiment

FIG. 5is a cross-sectional view illustrating the side of a light source unit according to a fourth embodiment. InFIG. 5, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIG. 5is similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the fourth embodiment is similar to the projector600in the first embodiment except for that a light source unit4is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit4in the fourth embodiment are now described with reference toFIG. 5.

The light source unit4in the fourth embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the fourth embodiment, a rectifying portion150included in a light source device64is different from the rectifying portion100included in the light source device61in the first embodiment. In the fourth embodiment, no support portion such as the support member110in the first embodiment is used. The rectifying portion150in the fourth embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment and performs operation similar to that of the rectifying portion100in the first embodiment.

In the fourth embodiment, the rectifying portion150includes a disk-shaped rectifying portion main body151having a flat surface. An opening151ais further formed at the center of the rectifying portion main body151. The rectifying portion150is produced by inserting the sealing portion82of the arc tube80through the opening151asuch that the rectifying portion150can be positioned in a direction substantially orthogonal to the illumination axis L. Then, the rectifying portion150is fixed to the sealing portion82by filling the clearance between the opening151aand the sealing portion82with the inorganic adhesive C such as cement. In this embodiment, a substantially constant clearance is produced between an outer circumferential end151bof the rectifying portion150and the opposed reflection layer in this condition. Anti-reflection processing is applied to the surface of the rectifying portion150similarly to the first embodiment, and the material constituting the rectifying portion150is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W4(indicated by broken lines with arrows) introduced through the air intake port9ato a space C4of the light source unit4by operation of the cooling mechanism500is now explained. The flow of the cooling air W4in this embodiment is substantially similar to the flow of the cooling air W2in the second embodiment.

The cooling air W4flows to the space C4of the housing9through the air intake port9aby the operation of the cooling mechanism500, and moves toward the reflector70. The cooling air W4having reached the reflector70flows along the reflection layer73of the reflector70. A part of the cooling air W4flows toward a space D4surrounded by the reflector70and the rectifying portion150via the clearance between the outer circumferential end151bof the rectifying portion150in the +Z direction and the reflection layer73. Most of the remaining cooling air W4flows in the direction along the flat surface of the rectifying portion150(−Z direction).

The cooling air W4flowing in the direction along the flat surface of the rectifying portion150(−Z direction) flows from the area A in the upper region of the light emission portion81to the area B on the reflector70side of the light emission portion81. By the flow of the cooling air W4, the area B as well as the area A are cooled. Then, the cooling air W4flows in the direction along the flat surface of the rectifying portion150(−Z direction), and again flows along the reflection layer73away from the rectifying portion150. Finally, the cooling air W4is discharged through the air discharge port9b.

On the other hand, the cooling air W4introduced to the space D4surrounded by the reflector70and the rectifying portion150cools the space D4, and again flows out through the clearance between the outer circumferential end151bin the −Z direction and the reflection layer73and moves along the reflection layer73. Then, the cooling air W4is discharged through the air discharge port9b.

The light source unit4according to the fourth embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that no support portion is included and that different structure and fixing method of the rectifying portion150of the light source device64are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device64in the fourth embodiment, the rectifying portion150is directly fixed to the sealing portion82. Thus, the structure can be simplified, and the manufacturing cost of the light source device64can be reduced.

Fifth Embodiment

FIG. 6illustrates a light source unit according to a fifth embodiment. More specifically,FIG. 6is a front view showing a connecting area between the light emission portion81and the one sealing portion82as viewed from the reflector70side, the connecting area containing a condition cut along a plane orthogonal to the illumination axis L. InFIG. 6, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIG. 6is similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the fifth embodiment is similar to the projector600in the first embodiment except for the point that a light source unit5is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit5in the fifth embodiment are now described with reference toFIG. 6.

The light source unit5in the fifth embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the fifth embodiment, a rectifying portion160included in a light source device65is different from the rectifying portion100included in the light source device61in the first embodiment. In the fifth embodiment, no support portion such as the support member110in the first embodiment is used. The rectifying portion160in the fifth embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment and performs operation similar to that of the rectifying portion100in the first embodiment.

In the fifth embodiment, the rectifying portion160includes a rectangular rectifying portion main body161having a flat surface. An opening161ais further formed at the center of the rectifying portion main body161. Corners162of the rectifying portion main body161are formed as tapered surfaces corresponding to the shape of the reflection layer73.

The rectifying portion160is produced by inserting the sealing portion82of the arc tube80through the opening161aand bringing the corners162of the rectifying portion160into contact with the reflection layer73in a direction substantially orthogonal to the illumination axis L. Then, the ends of the four corners162contacting the reflection layer73are fixed to the reflection layer73by the inorganic adhesive C such as cement. In this embodiment, clearances are produced between four outer circumferential ends161bof the rectifying portion160and the opposed reflection layer73in this condition. The opening161aof the rectifying portion160is positioned away from the outer circumferential surface of the sealing portion82of the arc tube80. Anti-reflection processing is applied to the surface of the rectifying portion160similarly to the first embodiment, and the material constituting the rectifying portion160is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W5(indicated by broken lines with arrows) introduced through the air intake port9ato a space of the light source unit5by operation of the cooling mechanism500is now explained. The flow of the cooling air W5in this embodiment is substantially similar to the flow of the cooling air W2in the second embodiment. Thus, only the point different from the second embodiment is herein explained.

The different point is that a part of the cooling air W5introduced to the space of the housing9flows to a space surrounded by the reflector70and the rectifying portion160through the clearance between the outer circumferential end161bof the rectangular rectifying portion160positioned in the +Z direction and the reflection layer73. The regulation of the flow direction of the cooling air W5by the rectifying portion160and the operation of the regulated cooling air W5are substantially similar to those in the second embodiment.

The light source unit5according to the fifth embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that no support portion is included and that different structure and fixing method of the rectifying portion160of the light source device65are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device65in the fifth embodiment, the rectifying portion160has a substantially rectangular flat shape. Thus, clearances are produced between the reflection layer73and the outer circumferential ends161bof the rectifying portion160by the difference between the inner surface shape of the reflection layer73and the rectangular shape of the rectifying portion160. Thus, the cooling air W5can be introduced to the space surrounded by the reflection layer73and the rectifying portion160through the clearances thus produced. The rectifying portion160having the substantially rectangular flat shape can be produced by only slight processing for forming the outer shape of the rectifying portion160. Thus, the manufacturing cost of the rectifying portion160can be reduced. Moreover, a larger number of the rectifying portion160having the rectangular flat shape can be produced from a material compared with the case of a circular rectifying portion. Thus, the manufacturing cost can be further reduced. In addition, resources can be efficiently used.

Sixth Embodiment

FIG. 7is a cross-sectional view illustrating the side of a light source unit according to a sixth embodiment. InFIG. 7, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIG. 7is similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the sixth embodiment is similar to the projector600in the first embodiment except for that a light source unit6is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit6in the sixth embodiment are now described with reference toFIG. 7.

The light source unit6in the sixth embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the sixth embodiment, a rectifying portion170included in a light source device66is different from the rectifying portion100included in the light source device61in the first embodiment. In the sixth embodiment, no support portion such as the support member110in the first embodiment is used. The rectifying portion170in the sixth embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment and performs operation similar to that of the rectifying portion100in the first embodiment.

In the sixth embodiment, the rectifying portion170includes a disk-shaped rectifying portion main body171having a curved surface. An opening171ais further formed at the center of the rectifying portion main body171. The rectifying portion170is produced by inserting the sealing portion82of the arc tube80through the opening171asuch that the rectifying portion170can be positioned in a direction substantially orthogonal to the illumination axis L. Then, the rectifying portion170is fixed to the sealing portion82by filling the clearance between the opening171aand the sealing portion82with the inorganic adhesive C such as cement. In this embodiment, a substantially constant clearance is produced between an outer circumferential end171bof the rectifying portion170and the opposed reflection layer73in this condition. Anti-reflection processing is applied to the surface of the rectifying portion170similarly to the first embodiment, and the material constituting the rectifying portion170is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W6(indicated by broken lines with arrows) introduced through the air intake port9ato a space C6of the light source unit6by operation of the cooling mechanism500is now explained. The flow of the cooling air W6in this embodiment is substantially similar to the flow of the cooling air W2in the second embodiment. Thus, only the point different from the second embodiment is herein described.

The different point is that most of the cooling air W6introduced to the space C6of the housing9smoothly flows in the direction along the curved surface of the rectifying portion170(−Z direction). A part of the cooling air W6flows to the space D6surrounded by the reflector70and the rectifying portion170through the clearance between the outer circumferential end171bof the rectifying portion170positioned in the +Z direction and the reflection layer73. The cooling air W6immediately before the air discharge port9balso smoothly flows along the curved surface of the rectifying portion170. The regulation of the flow direction of the cooling air W6by the rectifying portion170and the operation of the regulated cooling air W6are substantially similar to those in the second embodiment.

The light source unit6according to the sixth embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that no support portion is included and that different structure and fixing method of the rectifying portion170of the light source device66are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device66in the sixth embodiment, the rectifying portion170is directly fixed to the sealing portion82. Thus, the structure can be simplified, and the manufacturing cost of the light source device66can be reduced.

(2) According to the light source device66in the sixth embodiment, the rectifying portion170has a curved surface. In this case, the flow direction of the cooling air W6can be regulated while the cooling air W6is smoothly flowing along the curved surface. Thus, the flow of the cooling air W6can be easily controlled.

(3) According to the light source device66in the sixth embodiment, the rectifying portion170has a curved surface. On the other hand, each of the rectifying portions100,120,130,150, and160has a flat surface. Thus, highly efficient surfaces of the rectifying portion suited for the respective shapes of the arc tube, the reflector and the like included in the light source device and for the respective ways of flow of the cooling air can be selected with a higher degree of freedom.

Seventh Embodiment

FIG. 8is a cross-sectional view illustrating the side of a light source unit according to a seventh embodiment. InFIG. 8, similar reference numbers are given to parts similar to those in the first embodiment, and the same explanation is not repeated herein. The XYZ orthogonal coordinate system shown inFIG. 8is similar to the XYZ orthogonal coordinate system shown inFIG. 1and used in the first embodiment. The projector600in the seventh embodiment is similar to the projector600in the first embodiment except for the point that a light source unit7is included in lieu of the light source unit1in the optical systems of the projector600in the first embodiment.

The structure and operation of the light source unit7in the seventh embodiment are now described with reference toFIG. 8.

The light source unit7in the seventh embodiment includes the concave lens11and the housing9similarly to the first embodiment. In the seventh embodiment, a rectifying portion180included in a light source device67is different from the rectifying portion100included in the light source device61in the first embodiment. In the seventh embodiment, no support portion such as the support member110in the first embodiment is used. The rectifying portion180in the seventh embodiment is disposed between the one sealing portion82and the reflector70similarly to the rectifying portion100in the first embodiment and performs operation similar to that of the rectifying portion100in the first embodiment.

In the seventh embodiment, the rectifying portion180includes a disk-shaped rectifying portion main body181having a flat surface. An opening181ais further formed at a position shifted from the center of the rectifying portion main body181. The rectifying portion180is produced by inserting the sealing portion of the arc tube80through the opening181awith inclination to the illumination axis L at a predetermined angle. Then, the rectifying portion180is fixed to the sealing portion82by filling the clearance between the opening181aand the sealing portion82with the inorganic adhesive C such as cement. In this embodiment, the rectifying portion180is fixed with inclination to the illumination axis L at the predetermined angle. More specifically, the rectifying portion180in the +Z direction is fixed with inclination toward the light emission portion81.

In this embodiment, a substantially constant clearance is produced between an outer circumferential end181bof the rectifying portion180and the opposed reflection layer73. Anti-reflection processing is applied to the surface of the rectifying portion180similarly to the first embodiment, and the material constituting the rectifying portion180is similar to that of the rectifying portion100in the first embodiment.

The flow of cooling air W7(indicated by broken lines with arrows) introduced through the air intake port9ato a space C7of the light source unit7by operation of the cooling mechanism500is now explained. The flow of the cooling air W7in this embodiment is substantially similar to the flow of the cooling air W2in the second embodiment. Thus, only the point different from the second embodiment is herein described.

The different point is that most of the cooling air W7introduced to the space C7of the housing9smoothly flows in the direction along the inclined flat surface of the rectifying portion180(−Z direction). A part of the cooling air W7flows to a space D7surrounded by the reflector70and the rectifying portion180through the clearance between the outer circumferential end181bof the rectifying portion180positioned in the +Z direction and the reflection layer73. The regulation of the flow direction of the cooling air W7by the rectifying portion180and the operation of the regulated cooling air W7are substantially similar to those in the second embodiment.

The light source unit7according to the seventh embodiment has structure similar to that of the light source unit1(the light source device61) in the first embodiment except for that no support portion is included and that different structure and fixing method of the rectifying portion180of the light source device67are used. Thus, the following advantages as well as the corresponding ones of the advantages of the light source device61in the first embodiment are provided.

(1) According to the light source device67in the seventh embodiment, the rectifying portion180is directly fixed to the sealing portion82. Thus, the structure can be simplified, and the manufacturing cost of the light source device67can be reduced.

(2) According to the light source device67in the seventh embodiment, the rectifying portion180has a flat surface and is fixed not in the direction orthogonal to the illumination axis L but with inclination thereto. In this case, the flow direction of the cooling air W7can be regulated while the cooling air W7is smoothly flowing along the inclined flat surface. Thus, the flow of the cooling air W7can be easily controlled.

The invention is not limited to the first through seventh embodiments described herein, but may be practiced otherwise without departing from the scope and spirit of the invention. As such, various changes and improvements including the following modifications may be made.

Modified Example 1

While each of the light source devices61through67in the first through seventh embodiments includes the sub mirror90, the invention is applicable to a light source device not having the sub mirror90.

Modified Example 2

According to the light source devices61through in the first through seventh embodiments, the rectifying portions100,120,130,150,160,170, and180, the support members110and140, and others are provided. However, the shapes of the rectifying portions and the support members, the fixing structures and the like may be arbitrarily changed or combined without departing from the scope of the invention.

Modified Example 3

According to the light source devices61,64,66, and67in the first, fourth, sixth, and seventh embodiments, the rectifying portions100,150,170, and180are fixed to the sealing portion82by the inorganic adhesive C as an adhesive. In this case, the rectifying portion may be fixed to the sealing portion82by the adhesive at a position corresponding to an area out of the region where lines included in the electrode84are connected by welding or the like with the metal foil86sealed within the one sealing portion82(electrode connection region). When the rectifying portion is fixed by the adhesive in this manner, the effect caused by thermal stress can be reduced by avoiding the electrode connection region of the sealing portion82as an area easily affected by the effect of thermal stress.

Modified Example 4

According to the light source devices61through65, and67in the first through fifth embodiments and the seventh embodiment, the rectifying portions100,120,130,150,160, and180have flat surfaces. According to the light source device66in the sixth embodiment, however, the rectifying portion170has a curved surface. Thus, a highly efficient surface of the rectifying portion suited for the shapes of the arc tube, the reflector and the like included in the light source device and for the way of flow of the cooling air different from those in the first through seventh embodiments can be selected for producing the rectifying portion.

Modified Example 5

According to the first embodiment, the rectifying portion100and the support member110are separately produced, and then combined as one unit. However, the rectifying portion100and the support member110may be formed integrally with each other from the beginning.

Modified Example 6

According to the second embodiment, the rectifying portion120has the notches122on the edge. However, the shapes of the notches122may be changed such that effective cooling can be provided based on the consideration of the heat distribution inside the light source device62, the way of flow of the cooling air W2, and other conditions.

Modified Example 7

While each of the projectors600according to the first through seventh embodiments includes the lens integrator optical system containing the first lens array12and the second lens array13as the optical system for equalizing the illuminance of emitted light, a rod integrator optical system containing a light guide rod may be used.

Modified Example 8

While each of the projectors600according to the first through seventh embodiments is a front type projector, the invention is applicable to a rear type projector including a screen as a projection target surface in one unit.

Modified Example 9

According to the optical systems of the projectors600in the first through seventh embodiments, the liquid crystal devices30R,30G,30B as the optical modulation devices are transmission type liquid crystal devices. However, reflection type optical modulation devices such as reflection type liquid crystal devices may be used.

Modified Example 10

According to the optical systems of the projectors600in the first through seventh embodiments, the liquid crystal devices30R,30G,30B as the optical modulation devices are used. However, any type of optical modulation device may be employed as long as they can generally modulate entering light according to image signals. For example, micromirror type optical modulation devices may be used. The micromirror type optical modulation devices may be constituted by a DMD (digital micromirror device).

Modified Example 11

According to the optical systems of the projectors600in the first through seventh embodiments, the optical modulation devices are those of so-called three-plate type which includes the three liquid crystal devices30R,30G, and30B in correspondence with the red light, green light, and blue light. However, single-plate type may be employed. Moreover, a liquid crystal device for improving contrast may be added.

The present application claims priority from Japanese Patent Application No. 2009-057512 filed on Mar. 11, 2009, which is hereby incorporated by reference in its entirety.