Light source device, lighting device, monitoring device, and projector

A light source device includes: a light source unit which supplies light; a support unit which supports the light source unit; a covering unit which covers the light source unit; a wiring unit which connects a current supply section for supplying current to the light source unit and the light source unit; and a blade disposed at a position shifted toward the support unit from the wiring unit and penetrating through the covering unit.

BACKGROUND

1. Technical Field

The present invention relates to a light source device, a lighting device, a monitoring device, and a projector, and more particularly to a technology of a light source device included in a projector.

2. Related Art

Recently, a technology of a laser beam source for supplying laser beam used as a light source device of a projector has been proposed. The light source device using the laser beam source has advantages of high color reproducibility, ability of instantaneous turn-on, and long life compared with a UHP lamp used as a light source device in a projector in related art. However, the laser beam source gives uncomfortable effect to a human body, particularly to human eyes in some cases when the laser beam source emits light with a safety device removed. In case of infrared light, it is difficult to visually recognize the infrared light unlike visible light, and therefore the human body may receive harmful effect without recognizing it. In order to prevent these problems, it is demanded that extraction and bad use of the laser beam source by a person having no knowledge of laser beam source technology or the like is securely avoided. For satisfying this demand, a technology of preventing generation of laser beam from a laser resonator (laser beam source unit) having been removed for replacement or for other reasons (for example, see JP-A-2001-267670).

A safety device such as an interlock mechanism is provided on the laser beam device in the related art only for the purpose of preventing problems caused by carelessness during use. Thus, the technology in the related art is insufficient for preventing use of the laser beam device for purposes other than the original purpose such as the case of the laser resonator unit intentionally taken out from the laser beam device after disassembly for using the laser beam resonator for other purposes.

SUMMARY

It is an advantage of some aspects of the invention to provide a light source device capable of securely preventing problems caused by diverted use or bad use of a light source unit included in the light source device, and a lighting device, a monitoring device, and a projector including the light source device.

A light source device according to a first aspect of the invention includes: a light source unit which supplies light; a support unit which supports the light source unit; a covering unit which covers the light source unit; a wiring unit which connects a current supply section for supplying current to the light source unit and the light source unit; and a blade disposed at a position shifted toward the support unit from the wiring unit and penetrating through the covering unit.

For taking out the light source unit from the lighting device, the covering unit needs to be removed. Since the blade is disposed at the position shifted toward the support unit from the wiring unit and penetrating through the covering unit, the wiring unit is cut by the blade when the covering unit is removed. Power supply to the light source unit is cut off by the cutting of the wiring unit, and therefore problems caused by diverted use or bad use of the light source unit extracted from the light source device can be securely prevented. Thus, prevention of problems caused by diverted use or bad use of the light source unit can be securely achieved. Moreover, the light source device capable of preventing diverted use or bad use of the light source unit can be constructed by a simple structure.

A light source device according to a second aspect of the invention includes: a light source unit which supplies light; a support unit which supports the light source unit; a wiring unit which connects a current supply section for supplying current to the light source unit and the light source unit; and a blade disposed at a position shifted toward the support unit from the wiring unit. The support unit has a concave for accommodating the blade. The length of the blade in the depth direction of the concave is smaller than the depth of the concave. Since the blade is disposed at the position shifted toward the support unit from the wiring unit, the wiring unit can be cut by raising the blade. Moreover, the blade can be securely accommodated within the concave so as to avoid cutting of the wiring unit except for the case when the blade is raised. Thus, the light source device provided according to the second aspect of the invention can securely prevent problems caused by diverted use or bad use of the light source unit. In addition, the light source device capable of preventing diverted use or bad use of the light source unit can be constructed by a simple structure.

It is preferable that the support unit has a concave for accommodating the blade, and that the length of the blade in the depth direction of the concave is smaller than the depth of the concave. According to this structure, the blade can be securely accommodated within the concave. Thus, cutting of the wiring unit by the blade except for the case when the covering unit is removed can be avoided.

It is preferable to further include a spring unit which gives urging force for raising the blade toward the wiring unit. According to this structure, the blade can be securely raised by removing the covering unit. Thus, the wiring unit can be securely cut by removing the covering unit.

It is preferable that the cross section of the blade at one end is different in size from that at the other end. Since the blade is removable, breakage of the light source device at the time of maintenance or manufacture by a person having technical knowledge of the light source device or the like can be avoided. Moreover, since the shape of the cross section at one end is different from that at the other end, the blade is removable only in one direction. Thus, removal or disassembly of the blade by a person having no technical knowledge of the light source device or the like can be prevented. Accordingly, both prevention of problems and removal of the covering unit at the time of maintenance or manufacture can be achieved, and therefore easiness of maintenance can be increased.

It is preferable to further include a covering unit which covers the light source unit. In this case, the blade preferably has a screw structure provided at a portion engaging with the covering unit. Since the blade has the screw structure, only a person who has a driver having a special shape or the like can remove the blade. According to this structure, removal or disassembly of the blade by a person having no technical knowledge of the light source device or the like can be prevented. Accordingly, both prevention of problems and removal of the covering unit at the time of maintenance or manufacture can be achieved, and therefore easiness of maintenance can be increased.

It is preferable to further include a covering unit which covers the light source unit, and a holding member which holds the blade on the support unit side at the time of removal of the covering unit by being pushed to a position shifted toward the wiring unit from the blade. Since the holding member is provided, the covering unit can be removed while the blade is being held on the support unit side. Accordingly, removal of the covering unit at the time of maintenance or manufacture can be achieved, and therefore easiness of maintenance can be increased.

It is preferable to further include a plate member disposed in such a position as to contact one end of the holding member. In this case, the holding member is pushed by uniform push of the plate member through an opening formed on the covering unit. According to this structure, only a person who has a pin having a special structure or the like can remove the covering unit while the blade is being held on the support unit side. Accordingly, prevention of problems can be further securely achieved.

It is preferable that the support unit has a plug-in portion into which the holding member is plugged when the holding member is pushed to the position shifted toward the wiring unit from the blade. The plug-in portion preferably has a stopper mechanism which maintains the plug-in condition of the holding member. Since the stopper mechanism is provided, the condition where the blade is held on the support unit side can be maintained. Accordingly, breakage of the light source device during removal of the covering unit can be securely prevented, and therefore easiness of maintenance can be increased.

It is preferable that the support unit has an extruding mechanism which extrudes the holding member from a position above the blade. Since the extruding mechanism is provided, the holding member can be returned to the original position. Thus, return of the holding member to the original condition prior to the push can be achieved.

A lighting device according to a third aspect of the invention has the light source device described above and lights a light receiving object using light emitted from the light source device. Since the light source device described above is provided, problems caused by diverted use or bad use of the light source unit can be securely prevented. Accordingly, the lighting device provided according to the third aspect of the invention can securely prevent problems caused by diverted use or bad use of the light source unit.

A monitoring device according to a fourth aspect of the invention includes: the lighting device described above; and an image acquiring unit which acquires an image of a subject lighted by the lighting device. Since the lighting device described above is provided, problems caused by diverted use or bad use of the light source unit can be securely prevented. Accordingly, the monitoring device provided according to the fourth aspect of the invention can securely prevent problems caused by diverted use or bad use of the light source unit.

A projector according to a fifth aspect of the invention includes: the lighting device described above; and a spatial light modulating device which modulates light emitted from the lighting device according to an image signal. Since the lighting device described above is provided, problems caused by diverted use or bad use of the light source unit can be securely prevented. Accordingly, the projector provided according to the fifth aspect of the invention can securely prevent problems caused by diverted use or bad use of the light source unit.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Several embodiments according to the invention are hereinafter described in detail with reference to the drawings.

First Embodiment

FIG. 1schematically illustrates a structure of a light source device10according to a first embodiment of the invention. A semiconductor laser array11is a light source unit for supplying laser beam. A support unit12supports the semiconductor laser array11. A flexible substrate13is a current supply unit for supplying current to the semiconductor laser array11. A plurality of bonding wires14are provided between the semiconductor laser array11and the flexible substrate13. The bonding wires14are a wiring unit for connecting the flexible substrate13and the semiconductor laser array11.

A concave15is formed on the support unit12between the semiconductor laser array11and the flexible substrate13. The concave15linearly extends through the entire length of the support unit12below the bonding wires14. The concave15has a rectangular cross section. A light source cover17is formed such that the entire support unit12can be engaged therewith. The light source cover17is a covering unit for covering a part of the flexible substrate13, the semiconductor laser array11, and the bonding wires14.

A light emission unit18is provided on the light source cover17at a position corresponding to the position of the semiconductor laser array11. The light emission unit18is an opening formed on the light source cover17. The light emission unit18releases laser beam generated from the semiconductor laser array11within the light source cover17to the outside of the light source cover17. The light emission unit18may be a covering component made of transparent material. A blade16extends through the interior of the light source cover17in the left-right direction.

The blade16attached to the light source cover17is accommodated in the concave15while the light source cover17is covering the support unit12. In this condition, the blade16is disposed at a position shifted toward the support unit12from the bonding wires14and linearly extends through the light source cover17. The light source device10may use a light source unit constituted by diode pumped solid state (DPSS) laser, solid laser, liquid laser, gas laser, or the like as well as by semiconductor laser.

FIG. 2illustrates the structure of the blade16. The blade16is a bar-shaped component having rectangular cross section structure. Concerning a height HR and a width WR at a right end20of the blade16and a height HL and a width WL at a left end21of the blade16, the relation HL<HR or WL<WR holds. The blade16is so shaped as to have cross sections of the one right end20and the other left end21different from each other in size.

FIG. 3illustrates the cross section structure of the light source device10. When the light source cover17is removed from the support unit12with the blade16attached to the light source cover17, the blade16is raised with the light source cover17from the concave15. By the lift of the blade16from the support unit12, the blade16cuts the bonding wires14provided on the side opposite to the support unit12.

Thus, the blade16cuts the bonding wires14at the time of removal of the light source cover17. By cutting off power supply to the semiconductor laser array11achieved by cutting the bonding wires14, diverted use and bad use of the semiconductor laser array11extracted from the light source device10can be securely prevented. Accordingly, problems caused by diverted use or bad use of the light source unit can be securely prevented. Moreover, the device capable of preventing diverted use or bad use of the light source unit can be provided by a simple structure.

A height H of the blade16shown in the figure indicates the larger one of the height HR at the right end20and the height HL at the left end21. The height His the maximum length of the blade16in the depth direction of the concave15. Concerning the height H of the blade16and a depth h of the concave15, the relation H<h holds. In this structure, the blade16can be securely accommodated in the concave15. Thus, cutting the bonding wires14by the blade16can be avoided except for the case when the light source cover17is removed.

The blade16can be removed from the support unit12and the light source cover17while the light source cover17is being attached to the support unit12. After removal of the blade16, the light source cover17can be taken out without cutting the bonding wires14. Thus, the light source device10is not broken at the time of maintenance or manufacture by a person having technical knowledge of the light source device10, for example.

The blade16having the right end20larger than the left end21can be removed only in the right direction. Since the blade16can be removed only in one direction, removal or disassembly by a person having no technical knowledge of the light source device10or the like can be prevented. Particularly, the structure having the blade16which cannot be easily removed can be produced by slightly changing the size of the right end20from the size of the left end21. This structure prevents problems and allows removal of the light source cover17at the time of maintenance or manufacture, thereby increasing easiness of maintenance.

FIG. 4illustrates a blade in a modified example. A blade25shown inFIG. 4has a cylindrical shape having a circular cross section. A screw structure26is formed on each end of the blade25engaging with the light source cover17. The blade25is fixed to the light source cover17by screwing the screw structures26into the light source cover17.

A groove28is formed at an end surface27of the blade25. The groove28has a special shape unlike plus shape or minus shape used for an ordinary screw, such as a combination of star shapes as illustrated in the figure. A projection29is provided at the center of the groove28. In the condition where the blade25is fixed to the light source cover17, the blade25can be removed only by using a particular driver which fits with the special groove28and the projection29.

Thus, only a person who has a driver having a particular shape can remove the blade25, and removal of the blade25or disassembly of the light source device10by a person having no technical knowledge of the light source device10or the like can be prevented. In this case, removal of the light source cover17at the time of maintenance or manufacture and prevention of problems can be both achieved, and therefore easiness of maintenance can be increased similarly to the above example. The structure of the blade is not limited to those shown in this embodiment, but may be any structures as long as they can prevent removal of the light source device10by a person having no technical knowledge of the light source device10or the like.

Second Embodiment

FIG. 5illustrates a cross-sectional structure of a main part included in a light source device30according to a second embodiment of the invention. The light source device30is characterized by having a spring36and holding members37. Similar reference numbers are given to the components similar to those in the first embodiment, and the same explanation of those is not repeated. The cross section shown inFIG. 5is a cross section taken along a blade35and orthogonal to the bonding wires14. The spring36is a plate spring which gives urging force for pushing up the blade35toward the bonding wires14. The blade35has a deformed portion at a position corresponding to the position of the bonding wires14so as to form a space for accommodating the spring36between the blade35and a support unit32.

FIG. 6is a perspective view illustrating a structure of a light source cover31. A concave34is formed on each of the left and right sides of a light source cover31. The concave34has a rectangular shape substantially the same as the cross-sectional shape of the blade35. The concave34pushes both ends of the blade35against the support unit32while the light source cover31is being attached to the support member32(seeFIG. 5). When the light source cover31is removed from the support unit32, the concave34releases pushing given to the blade35. As a result, the blade35is raised toward the bonding wires14by the urging force of the spring36. Thus, the bonding wires14can be securely cut at the time of removal of the light source cover31by using the urging force of the spring36.

Returning toFIG. 5, the holding members37are provided at two positions above the blade35and close to the light source cover31. Each of the holding members37has a cross-shaped cross section, and is a cylindrical component whose longitudinal direction corresponds to the direction orthogonal to the sheet surface of the figure. As illustrated inFIG. 6, the light source cover31has pin insertion holes33at positions corresponding to the positions of the holding members37. Each of the pin insertion holes33is an opening formed on the light source cover31and has a cross shape substantially the same as the cross section of the holding member37.

FIG. 7illustrates a cross-sectional structure of the part having the holding members37in the structure shown inFIG. 5. Each of the holding members37is disposed within a through hole39. The through hole39formed on the support unit32above the blade35extends therethrough in the direction orthogonal to the blade35. The holding member37is pushed into a position between the blade35and the bonding wires14by a pin38inserted through the pin insertion hole33.

The holding member37pushed into the position shifted toward the bonding wires14from the blade35holds the blade35at a position on the support unit32side at the time of removal of the light source cover31. An air supply hole40is formed on the light source cover31at a position corresponding to the through hole39on the side opposite to the pin insertion hole33. After attachment of the light source cover31, air is supplied through the air supply hole40to shift the holding member37from the position above the blade35toward the position of the pin insertion hole33. The air supply hole40and the through hole39constitute an extruding mechanism for extruding the holding member37from the position above the blade35toward the position of the pin insertion hole33. This mechanism returns the holding member37to the original condition before the holding member37is pushed.

For pushing the holding member37from the position near the pin insertion hole33to the position above the blade35through the through hole39, the pin38having a shape allowing insertion into the pin insertion hole33is needed. Thus, only a person having the pin38can push the blade35, and pushing of the blade35and disassembly of the light source device30by a person having no technical knowledge of the light source device30or the like can be prevented. In this case, removal of the light source cover31at the time of maintenance or manufacture and prevention of problems can be both achieved, and therefore easiness of maintenance can be increased similarly to the above examples.

The cross-sectional shapes of the pin insertion hole33and the holding member37are not limited to those in this embodiment, but may be other shapes as long as the holding member37can be easily pushed by using an object other than the pin38having a shape allowing insertion into the pin insertion hole33. In this case, a more complicated shape is preferable for reducing possibilities of diverted use or bad use of the semiconductor laser array11. The structure of the holding member37is not limited to the mechanism which shifts the holding member37toward the pin insertion hole33by the airflow supplied through the air supply hole40. For example, the holding member37may be extruded toward the pin insertion hole33by insertion of a pin from the air supply hole40side.

FIG. 8illustrates a cross-sectional structure of a main part included in a light source device50in a modified example of this embodiment. The light source device50according to this modified example has a holding member43having a shape different from that of the light source device30in the above example. As can be seen from the cross-sectional view, the holding member43has a rectangular shape. As illustrated in the perspective view of the structure shown inFIG. 9, a pin insertion hole41is formed on a light source cover53at a position corresponding to each of the holding members43. Each of the pin insertion holes41is an opening formed on the light source cover53, and has four circular shapes at positions corresponding to vertexes of a square.

Each ofFIGS. 10A and 10Billustrates a cross-sectional structure of a part having the holding member43in the structure shown inFIG. 8.FIG. 10Ashows the condition where the holding member43is disposed at a position shifted toward the pin insertion hole41from a position above the blade35. A plate member45as a plate-shaped component is provided between the holding member43and the pin insertion hole41. The plate member45contacts one end of the holding member43on the pin insertion hole41side. The plate member45and the holding member43may be provided as one body.

The holding member43has a vane49provided in the vicinity of the center of a bar-shaped member having a rectangular cross section. The vane49has a thin plate shape and is disposed orthogonal to the longitudinal direction of the bar-shaped member. A distal end51of the holding member43on the side opposite to the plate member45has a tapered shape gradually tapered toward the end. A support unit42has a space around the holding member43. A part of the space ranging from the plate member45to the vane49has a width sufficient for the movement of the plate member45. A part of the space ranging from the vane49to the distal end51has a width sufficient for the movement of the vane49. A part of the space ranging from the distal end51to the tip has a width sufficient for receiving the bar-shaped member of the holding member43. A spring44is provided in the part of the space for shifting the vane49. The spring44gives urging force for pushing the vane49toward the pin insertion hole41.

A plug-in portion46is formed on a support unit42on the side opposite to the holding member43as viewed from the blade35. The plug-in portion46has a shape slightly smaller than the shape of the distal end51. A through hole52extends from the plug-in portion46to an air supply hole48.

FIG. 10Bshows a condition where the holding member43is pushed from the position shown inFIG. 10Atoward the position above the blade35. For pushing the holding member43at the position shown inFIG. 10Ato the position above the blade35, the plate member45needs to be uniformly pushed by a pin47having a shape allowing insertion into the pin insertion hole41. The holding member43is pushed by the uniform push of the plate member45via the pin insertion hole41.

The holding member43pushed by the pin47shifts to the position above the blade35while contracting the spring44via the vane49. At the time of removal of the light source cover53, the holding member43is pushed to the position shifted toward the bonding wires14from the blade35to hold the blade35on the support unit42side. When the holding member43is pushed to the position above the blade35, the distal end51is plugged into the plug-in portion46. The plug-in portion46having a shape slightly smaller than that of the distal end51fixes the distal end51under the condition where the distal end51is plugged into the plug-in portion46. Thus, the holding member43remains at the position above the blade35after pushing of the plate member45by the pin47is stopped. Accordingly, the plug-in portion46constitutes a stopper mechanism for maintaining the condition of the distal end51of the holding member43inserted into the plug-in portion46.

The condition where the blade35is retained on the support unit42side can be maintained by the stopper mechanism. Thus, breakage of the light source device50during removal of the light source cover53can be securely avoided, and easiness of maintenance can be further increased. After the light source cover53is attached, air is supplied through the air supply hole48to shift the supporting member43from the position above the blade35to the position on the pin insertion hole41side. The air hole48and the through hole52constitute an extruding mechanism for extruding the holding member43from the position above the blade35.

For uniformly pushing the plate member45, the pin47having a shape allowing insertion into the pin insertion hole41is needed. The structure according to this modified example prevents problems and allows removal of the light source cover53at the time of maintenance or manufacture, thereby increasing easiness of maintenance. The shape of the pin insertion hole41is not limited to that shown in this modified example, but may be other shapes as long as an object other than the pin47allowing insertion into the pin insertion hole41cannot easily push the holding member43. A more complicated shape is preferable for reducing possibilities of diverted use or bad use of the semiconductor laser array11.

The plug-in member46is not limited to the shape slightly smaller than that of the distal end51, but may be other shapes as long as the condition of the holding member43plugged into the plug-in portion46can be retained. For example, the plug-in portion46may have a shape capable of engaging with a part of the holding member43to obtain the function of the stopper mechanism. The structure of the holding member43and the shape of the support unit42in the area for shifting the holding member43are not limited to those shown in this modified example. Appropriate modifications and changes may be made for those structures as long as the same advantages as those in this modified example can be offered.

Third Embodiment

FIG. 11schematically illustrates a structure of a projector60according to a third embodiment of the invention. The projector60is a front-projection-type projector which supplies light to a screen68and obtains reflection light reflected by the screen68as light to be observed as an image. The same explanation as that in the first embodiment is not repeated. The projector60includes a lighting device61R for red (R) light, a lighting device61G for green (G) light, and a lighting device61B for blue (B) light. The projector60displays an image by using lights emitted from the respective lighting devices61R,61G and61B.

The R light lighting device61R is a lighting device which supplies R light. A field lens62collimates the R light emitted from the R light lighting device61R, and supplies the collimated R light to an R light spatial light modulating device63R as a light receiving object. The R light spatial light modulating device63R is a spatial light modulating device which modulates the R light from the R light lighting device61R according to an image signal, and is constituted by a transmission-type liquid crystal display device. The transmission-type liquid crystal display device may be a high temperature polysilicon (HTPS) TFT liquid crystal panel, for example. The R light modulated by the R light spatial light modulating device63R enters a cross dichroic prism64as a color synthesizing optical system.

The G light lighting device61G is a lighting device which supplies G light. The field lens62collimates the G light emitted from the G light lighting device61G, and supplies the collimated G light to a G light spatial light modulating device63G. The G light spatial light modulating device63G is a spatial light modulating device which modulates the G light from the G light lighting device61G according to an image signal, and is constituted by a transmission-type liquid crystal display device. The G light modulated by the G light spatial light modulating device63G enters the cross dichroic prism64from a side different from the side the R light enters.

The B light lighting device61B is a lighting device which supplies B light. The field lens62collimates the B light emitted from the B light lighting device61B, and supplies the collimated B light to a B light spatial light modulating device63B. The B light spatial light modulating device63B is a spatial light modulating device which modulates the B light from the B light lighting device61B according to an image signal, and is constituted by a transmission-type liquid crystal display device. The B light modulated by the B light spatial light modulating device63B enters the cross dichroic prism64from a side different from the sides the R and G lights enter.

The cross dichroic prism64has a pair of dichroic films65and66disposed substantially orthogonal to each other. The first dichroic film65reflects R light and transmits G and B lights. The second dichroic film66reflects B light and transmits R and G lights. The cross dichroic prism64synthesizes the R, G and B lights entering in different directions, and releases the light after synthesis toward a projection lens67. The projection lens67projects the light produced by synthesis of the cross dichroic prism64toward the screen68.

FIG. 12illustrates the structure of the G light lighting device61G as a lighting device. The G light lighting device61G lights the G light spatial light modulating device63G as a light receiving object (seeFIG. 11) by using laser beam supplied from a light source device70. A semiconductor laser array71is covered by a light source cover72. The semiconductor laser array71is a light source unit for supplying laser beam, and supplies laser beam having 1064 nm, for example. The light source device70has the same structure as that of the light source device discussed in the first or second embodiment.

An SHG element73is contained in a jacket74. The SHG element73is a wavelength converting element which converts the wavelength of the laser beam emitted from the semiconductor laser array71. The SHG element73converts the laser beam emitted from the semiconductor laser array71into laser beam having 532 nm which is half of the original wavelength. The SHG element73may be constituted by a nonlinear optical crystal such as periodically poled lithium niobate (LiNbO3) abbreviated as PPLN.

The laser beam converted into laser beam having the desired wavelength by the SHG element73passes a resonant mirror75, and travels toward a diffusing element76. Laser beam having wavelengths other than the desired wavelength is reflected by the resonant mirror75. The laser beam converted into laser beam having the desired wavelength in the area between the semiconductor laser array71and the resonant mirror75passes the resonant mirror75and travels toward the diffusing element76. This structure allows efficient release of the laser beam having the desired wavelength.

The jacket74may be constituted by a material having high heat conductivity such as copper. The jacket74contains a temperature control unit and a temperature measuring unit (both not shown). The temperature control unit keeps the temperature of the SHG element73substantially constant. The temperature control unit may be constituted by a heater or a Peltier element, for example. Heat can be uniformly supplied to the entire SHG element73by using the temperature control unit equipped within the jacket74. The temperature measuring unit measures the temperature of the SHG element73. The temperature of the SHG element73can be controlled with high accuracy by feedback control over the temperature control unit based on the measurement result obtained by the temperature measuring unit. Since the temperature of the SHG element73is kept substantially constant, high wavelength conversion efficiency can be maintained. Accordingly, supply of laser beam can be achieved with high efficiency.

The diffusing element76shapes and enlarges the lighting range, and equalizes light quantity distribution of laser beam. The diffusing element76may be constituted by a computer generated hologram (CGH) as a diffraction optical element, for example. The R light lighting device61R and the B light lighting device61B can be constructed to have the same structure as that of the G light lighting device61G except that the lighting devices61R and61B emit lights different from the light from the lighting device61G.

Problems caused by diverted use or bad use of the light source unit can be securely prevented by using the light source device70which is similar to the light source device used in the first or second embodiment described above. The projector60is not limited to a projector which uses transmission-type liquid crystal display devices as spatial light modulating devices, but may use reflection type liquid crystal display devices (liquid crystals on silicon (LCOS), DMDs (digital micromirror devices), GLV (grating light valves) or the like. The projector60is not limited to a projector having spatial light modulating devices for the respective lights, but may modulate two, three or a larger number of color lights by one spatial light modulating device. The projector may be a so-called rear projector which supplies light to one surface of the screen and obtains light released from the other surface of the screen as light to be observed as an image.

Fourth Embodiment

FIG. 13schematically illustrates a monitoring device80according to a fourth embodiment of the invention. The monitoring device80includes a device main body81and a light guide unit82. The device main body81has the light source device70similarly to the projector60in the third embodiment. The same reference numbers are given to the same parts as those in the third embodiment, and the same explanation is not repeated.

The light guide unit82has two light guides84and85. A diffusing plate86and an image formation lens87are provided at the end of the light guide unit82on a subject (not shown) side. The first light guide84guides light emitted from the light source device70toward the subject. The diffusing plate86is provided on the light emission side of the first light guide84. The light having propagated within the first light guide84passes through the diffusing plate86to be diffused on the subject side. The respective components along the optical path from the light source device70to the diffusing plate86constitute a lighting device for lighting the subject.

The second light guide85guides light coming from the subject toward a camera83. The image formation lens87is provided on the light entrance side of the second light guide85. The image formation lens87converges the light coming from the subject on the light entrance surface of the second light guide85. After entering the second light guide85via the image formation lens87, the light from the subject propagates within the second light guide85and enters the camera83.

The first light guide84and the second light guide85can be formed by combining a number of optical fibers. Laser beam can be supplied to a distant place by using the optical fibers. The camera83is equipped within the device main body81. The camera83is an image acquiring unit which acquires an image of the subject lighted by the respective components disposed along the optical path from the light source device70to the diffusing plate86. The camera83acquires the image of the subject by using the light entering through the second light guide85into the camera83.

Problems caused by diverted use or bad use of the light source unit can be securely prevented by using the light source device70similar to the light source device used in the first or second embodiment described above. The light source device according to the invention is applicable not only to a projector or a monitoring device, but also to an exposing device which uses laser beam, for example. In addition, the light source device according to each of the embodiments of the invention is not limited to the structure using the laser beam source as the light source unit, but may be a structure which employs a lamp such as a solid light source like LED and an extra-high pressure mercury lamp for the light source unit.

Accordingly, the light source device according to each of the embodiments of the invention is appropriately used for a lighting device included in a projector or a monitoring device.

The entire disclosure of Japanese Patent Application No. 20070003096, filed Jan. 11, 2007 is expressly incorporated by reference herein.