Light source unit and projector

A light source unit includes a blue laser diode of an excitation light shining device for emitting light in a first wavelength range, a red light source of a red light source device for emitting light in a second wavelength range, a luminescent wheel including a wavelength transforming area for transforming the light in the first wavelength range into light in a third wavelength range differing in wavelength range from the light in the first wavelength range and the light in the second wavelength range and emitting the light in the third wavelength range and a transmitting area for emitting the light in the first wavelength range, the wavelength transforming area and the transmitting area being provided end to end in a circumferential direction, and a dichroic mirror configured to transmit one of the lights in the first and second wavelength ranges and reflect a remaining light.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a light source unit and a projector including this light source unit.

Description of the Related Art

There have conventionally been disclosed projectors that include a blue light source device for emitting light having a wavelength in the blue wavelength range or simply light in the blue wavelength range, a luminescent wheel including a luminescent light emitting area configured to receive light from the blue light source device as excitation light to thereby emit light having a wavelength in the green wavelength range or simply light in the green wavelength range and a diffuse transmitting area, and a red light source device for emitting light having a wavelength in the red wavelength range or simply light in the red wavelength range. For example, in Japanese Patent Laid-Open No. 2018-159835 (JP-A-2018-159835), light in the green wavelength range, which is luminescent light, is emitted to a front side of a luminescent wheel. Light in the blue wavelength range, which is light emitted from a blue light source device, is transmitted through a diffuse transmitting area on the luminescent wheel while being diffused and is then guided onto the same optical path as those of light in the green wavelength range and light in the red wavelength range by way of multiple reflection mirrors and collective lenses after it emerges from a back side of the luminescent wheel.

As in a luminescent wheel device of the projector disclosed in JP-A-2018-159835, when the blue light source device for emitting light in the blue wavelength range is used as a light source for excitation light which is used in the luminescent wheel, which is configured to emit luminescent light from the front side thereof, optical elements need to be disposed for guiding light in the blue wavelength range accordingly from the back side of the luminescent wheel, which sometimes results in enlargement in size of the projector.

SUMMARY OF THE INVENTION

The present invention has been made in view of the situations described above, and an object of the present invention is to provide a small light source unit and a projector which is made small in size by including the light source unit.

According to a first aspect of the present invention, there is provided a light source unit including a first light source for emitting light in a first wavelength range, a second light source for emitting light in a second wavelength range which differs in wavelength range from the light in the first wavelength range, a wheel including a wavelength transforming area configured to receive the light in the first wavelength range that is incident thereon from a first surface side to thereby transform the light in the first wavelength range into light in a third wavelength range which differs in wavelength range from the light in the first wavelength range and the light in the second wavelength range and emit the light in the third wavelength range from a second surface side and a transmitting area for emitting the light in the first wavelength range that is incident thereon from the first surface side from the second surface side, the wavelength transforming area and the transmitting area being provided end to end in a circumferential direction, and a dichroic mirror configured to transmit one of the light in the first wavelength range and the light in the second wavelength range and to reflect a remaining light.

According to a second aspect of the present invention, there is provided a projector including the light source unit described above, a display device onto which light source light from the light source unit is shined to thereby form image light, a projection optical system for projecting the image light emitted from the display device onto a screen, and a projection control unit for controlling the display device and the light source unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

First Embodiment

Hereinafter, a first embodiment of the present invention will be described.FIG. 1is a block diagram showing functional circuitries of a projector control unit of a projector10. The projector control unit is configured of CPU including an image transforming section23and a processor38, a front-end unit including an input/output interface22, and a formatter unit including a display encoder24and a display drive section26.

The processor38governs the control of operations of individual circuitries inside the projector10and is configured of CPU, ROM that stores fixedly operation programs such as various settings or the like, RAM that is used as a work memory, and the like.

Then, with this control means, image signals of various standards which are input from an input/output connector section21are sent to the image transforming section23via the input/output interface22and a system bus (SB), and the image signals so sent are then transformed so as to be unified into an image signal of a predetermined format which is suitable for display in the image transforming section23. Thereafter, the unified image signal is output to the display encoder24.

Additionally, the display encoder24deploys the image signal input thereinto on a video RAM25for storage therein and generates a video signal from the contents of the video RAM25stored therein, outputting the video signal so generated to the display drive section26.

The display drive section26functions as a display device control means and drives a display device51, which is a spatial optical modulator (SOM), at an appropriate frame rate in response to the image signal output from the display encoder24.

Then, in this projector10, a pencil of light emitted from a light source unit60is shined onto the display device50via an optical system, whereby an optical image is formed with light reflected by the display device50, and the image so formed is then projected onto a projection target member such as a screen, not shown, via a projection optical system for display on the screen. A movable lens group235of the projection optical system can be driven by a lens motor45for zooming and focusing.

An image compression/expansion section31performs a recording process in which a luminance signal and a color difference signal of the image signal are data compressed through processing such as Adaptive Discrete Cosine Transform (ADCT), Huffman effect and the like, and the compressed data is sequentially written on a memory card32, which is a detachable recording medium.

Further, with the projector10set in a reproducing mode, the image compression/expansion section31performs a process in which the image compression/expansion section31reads out the image data recorded in the memory card32and expands the individual image data that makes up a series of dynamic images frame by frame, outputting the image data to the display encoder24by way of the image transforming section23, whereby dynamic images or the like can be displayed based on the image data stored in the memory card32.

A keys/indicators section37is configured of main keys, indicators, and the like which are provided on a casing of the projector10, and operation signals of the keys/indicators section37are sent out directly to the processor38. Key operation signals from a remote controller are received by an IR reception section35and are then demodulated into a code signal in an Ir processing section36for output to the processor38.

The processor38is connected with an audio processing section47byway of the system bus (SB). This audio processing section47includes a circuitry for a sound source such as a PCM sound source. With the projector10set in a projection mode and the reproducing mode, the audio processing section47converts audio data into analog signals and drives a speaker48to output loudly sound or voice based on the audio data.

The processor38controls a light source control circuit41, which acts as a light source control unit. This light source control circuit41controls separately light emitting operations of a red light source device, a green light source device, and a blue light source device of the light source unit60in such a manner that lights in predetermined wavelength ranges required in generating an image are emitted from the light source unit60.

Further, the processor38causes a cooling fan drive control circuit43to detect temperatures using multiple temperature sensors which are provided in the light source unit60and the like so as to control revolution speeds of cooling fans based on the results of the temperature detections. In addition, the processor38also causes the cooling fan drive control circuit43to keep the cooling fans revolving by use of a timer or the like even after a power supply to a main body of the projector10is switched off. Alternatively, the processor38causes the cooling fan drive control circuit43to switch off the power supply to the main body of the projector10depending upon the results of the temperature detections by the temperature sensors.

Next, an internal structure of the projector10will be described.FIG. 2is a schematic plan view showing the internal structure of the projector10. Here, the casing of the projector10has a substantially box-like shape and includes an upper surface and a lower surface, a front panel12, a back panel13, a right panel14, and a left panel15. In the following description, when directions are referred to in relation to the projector10, left and right refer, respectively, to left and right directions with respect to a projecting direction, and front and rear refer, respectively, to front and rear directions with respect to a direction of the projector10directed towards a screen and a traveling direction of a pencil of light.

The projector10includes a control circuit board241in the vicinity of the right panel14. This control circuit board241includes a power supply circuitry block, a light source control block, and the like. In addition, the projector10includes the light source unit60provided at a side of the control circuit board241, that is, at a substantially central portion of the casing of the projector10. Further, the projector10includes a light source-side optical system170and a projection optical system220, which are disposed between the light source unit60and the left panel15.

The light source unit60includes an excitation light shining device700, which constitutes not only a light source for light having a wavelength in the blue wavelength range or simply light in the blue wavelength range (light in a first wavelength range) but also an excitation light source, a red light source device120, which constitutes a light source for light having a wavelength in the red wavelength range or simply light in the red wavelength range (light in a second wavelength range), and a green light source device80, which constitutes a light source for light having a wavelength in the green wavelength range or simply light in the green wavelength range (light in a third wavelength range). The green light source device80is configured of the excitation light shining device700and a luminescent wheel device100. In addition, in the light source unit60, a light guiding optical system140is disposed which is configured to guide light in the blue wavelength range, light in the green wavelength range, and light in the red wavelength range. The light guiding optical system140includes a dichroic mirror146and a reflecting mirror147(a total reflecting mirror) and collects lights in the blue, green and red wavelength ranges which are emitted from the excitation light shining device700, the green light source device80, and the red light source device120, respectively, to an incident port of a light tunnel175.

The excitation light shining device700, which constitutes a light source device, is disposed at a substantially central portion in the casing of the projector10in a left-right direction thereof. In the excitation light shining device700, multiple blue diodes71(a first light source), which are a total of eight semiconductor light emitting elements arranged in a matrix configuration of two rows and four columns, are held in place on a holding member730. Collimator lenses73are disposed individually on respective optical axes of the blue laser diodes71to convert lights emitted from the blue laser diodes71into parallel lights so as to enhance the directivity thereof. The excitation light shining device700is disposed in such a manner that light emitted therefrom travels in the direction of the front panel12.

A heat sink81is provided for the excitation light shining device700, and this heat sink81is thermally connected with the holding member73by way of a heat pipe, not shown, or the like. A cooling fan261is disposed between the heat sink81and the back panel13, so that the blue laser diodes71are cooled by the cooling fan261and the heat sink81. A cooling fan261is also disposed between the excitation light shining device700and the back panel13.

The luminescent wheel device100of the green light source device80includes a luminescent wheel101, a motor110, a collective lens group111, and a collective lens115. The luminescent wheel101is disposed in such a manner as to be parallel to the right panel14, that is, in such a manner as to intersect at right angles to an axis of light in the blue wavelength range which is reflected by the dichroic mirror146to act as excitation light. The collective lens group111collects excitation light so as to be shined onto the luminescent wheel101, while the collective lens115collects a pencil of light which is emitted from the luminescent wheel101in the direction of the left panel15.

As shown inFIG. 3, the luminescent wheel101is formed of a plate-like metallic base101ahaving a circular disk shape. A motor shaft112of the motor110is connected to a center of the luminescent wheel101, whereby the luminescent wheel101is rotationally driven by the motor110. A luminescent light emitting area102(a wavelength transforming area), a diffuse transmitting area103a, and a transmitting area103bare provided end to end on the metallic base101aof the luminescent wheel101(a wheel). The luminescent light emitting area102is formed over an angular range of about 200 degrees, the diffuse transmitting area103ais formed over an angular range of about 60 degrees, and the transmitting area103bis formed over an angular range of about 100 degrees. The luminescent light emitting area102, the diffuse transmitting area103a, and the transmitting area101bare individually fitted in the metallic base101a.

The luminescent light emitting area102is formed of a transmitting luminescent body of a circular arc-shaped plate. In this transmitting luminescent body, excitation light is incident thereon from one surface or a first surface side, and luminescent light excited by the excitation light is emitted from the other surface or a second surface side thereof. The transmitting luminescent body can be formed, for example, by dispersing a luminescent material in a binder of an organic family or a binder of an inorganic family such as a silicone resin, an epoxy resin, or the like for solidification or as a sintered body of a powder mixture of a glass powder and a luminescent material powder. Alternatively, the transmitting luminescent body can also be formed by laying a luminescent material on one surface or a first surface, or the other surface or a second surface of a light transmitting glass which is formed into an arc-shaped plate.

Luminescent light emitted from the luminescent material of the transmitting luminescent body is emitted in every direction. Consequently, a filter configured to transmit or reflect predetermined light is provided on a one surface or first surface side, or the other surface or a second surface side of the transmitting luminescent body. For example, in the case that the filter is provided on the first surface side (in this first embodiment, a front surface side of the luminescent wheel101) on which excitation light is incident, the filter is configured to transmit excitation light (light in the blue wavelength range) and reflect luminescent light (ling in the green wavelength range). On the other hand, in the case that the filter is provided on the second surface side (in this first embodiment, a back surface side of the luminescent wheel101) which is opposite to the side on which excitation light is incident, the filter is configured to reflect excitation light and transmit luminescent light.

The diffuse transmitting area103ais formed as an area on which light in the blue wavelength range from the excitation light shining device700, which is laser light, is incident and which is configured to transmit the laser light while diffusing it. For example, the diffuse transmitting area103ais formed of a diffuse plate in the form of an arc-shaped plate. On the other hand, the transmitting area103bis formed as an area which is configured to transmit light in the red wavelength range from the red light source device120without diffusing it. For example, the transmitting area103bis formed of a glass plate in the form of an arc-shaped plate. Thus, the diffuse transmitting area103aand the transmitting area103bmake up the transmitting area103which emits light which is incident thereon from one surface or a first surface side from the other surface or a second surface side thereof.

The red light source device120includes a red light source121disposed in such a manner as to emit light in the direction of the left panel15and a collective lens group125for collecting light emitted from the red light source121. This red light source121is a red light emitting diode (a second light source) which is a semiconductor light emitting element for emitting light in the red wavelength range. The red light source device120includes a heat sink130which is disposed at a side of the red light source121which faces the right panel14. A cooling fan261is disposed on a side of the heat sink130which faces the right panel14to cool the heat sink130, which then cools the red light source121.

The dichroic mirror146is disposed in a position where light emitted from the red light source device120and light emitted from the excitation light shining device700intersect. The dichroic mirror146transmits light in the red wavelength range and reflects light in the blue wavelength range. As a result, light in the red wavelength range emitted from the red light source device120passes through the dichroic mirror146and is then incident on the collective lens group111. On the other hand, an axis of light in the blue wavelength range emitted from the excitation light shining device700is changed in direction through 90 degrees to be reflected towards the left panel15and is eventually incident on the collective lens group111.

The reflecting mirror147is disposed on a side of the collective lens115which faces the left panel15. The reflecting mirror147changes the direction of an axis of light emitted from the collective lens115through 90 degrees to reflect the light towards the back panel13, causing the light to be incident on a collective lens173of the light source-side optical system170. A configuration may be adopted in which light emitted from the collective lens115is caused to be incident directly on the collective lens173without providing the reflecting mirror147.

The light source-side optical system170includes the collective lens173, the light tunnel175, a collective lens178, a light axis changing mirror181, a collective lens183, a shining mirror185, and a condenser lens915. The condenser lens195emits image light emitted from the display device51, which is disposed on a side of the condenser lens195which faces the back panel13, towards the projection optical system220, and therefore, the condenser lens195is included in the projection optical system220as a part thereof.

The collective lens173is disposed in the vicinity of the light tunnel175to collect light source light to the incident port of the light tunnel175. As a result, light in the red wavelength range, light in the green wavelength range, and light in the blue wavelength range, which are reflected by the reflecting mirror147, are collected by the collective lens173to be incident on the light tunnel175. A pencil of light incident on the light tunnel175is transformed into a pencil of light whose intensity is distributed more uniformly by the light tunnel175.

The light axis changing mirror181is disposed by way of the collective lens178on an optical axis of the light tunnel175at a side of the light tunnel175which faces the back panel13. A pencil of light emerging from an emerging port of the light tunnel175is collected by the collective lens178, whereafter an axis of the pencil of light so collected is then changed in direction towards the left side panel15by the light axis changing mirror181.

The pencil of light reflected by the light axis changing mirror181is collected by the collective lens183and is then shined onto the display device51at a predetermined angle by way of the condenser lens195by the shining mirror185. In the first embodiment, the display device51is the digital micromirror device or DMD, and a heat sink190is provided at a side of the display device51which faces the back panel13, whereby the display device51is cooled by this heat sink190.

The pencil of light, which is light source light, shined onto an image forming plane of the display device51by the light source-side optical system170is reflected by the image forming plane of the display device51and is then projected onto a screen by way of the projection optical system220as projected light. Here, the projection optical system220includes the condenser lens195, the movable lens group235and a fixed lens group225. The movable lens group235can be moved by a lens motor. The movable lens group235and the fixed lens group225are incorporated in a fixed lens barrel. As a result, the fixed lens barrel incorporating therein the movable lens group235is made into a variable-focus lens and is configured so as to enable zooming and focusing.

With the projector10configured as described heretofore, the excitation light shining device700and the red light source device120are selectively driven by the light source control circuit41in accordance with an image signal inputted by way of the input/output interface22. As a result, lights are emitted at different timings from the excitation light shining device700and the red light source device120. Then, lights in the red, green, and blue wavelength ranges which are emitted from the excitation light shining device700, which constitutes the blue light source, the green light source device80, and the red light source device120, respectively, are sequentially incident on the collective lens173and the light tunnel175by way of the light guiding optical system140and are then incident on the display device51by way of the light source-side optical system170, whereby DMD, which is the display device51of the projector10, displays the blue, green and red lights in accordance with the data in a time dividing fashion, thereby making it possible for a color image to be projected onto the screen.

Second Embodiment

Next, a second embodiment of the present invention will be described based onFIG. 4. A projector10A according to this second embodiment differs from the projector10according to the first embodiment in that the arrangement of the excitation light shining device700of the first embodiment is changed. In this second embodiment, an excitation light shining device700is disposed in such a manner that light emitted therefrom becomes parallel to light emitted from a red light source device120. As a result, in relation to shining spots formed on a luminescent wheel101, a shining spot is formed on which light in the blue wavelength range from the excitation light shining device700is shined, in addition to a shining spot on which light in the red wavelength range from the red light source device120is shined.

The two shining spots can be set in arbitrary circumferential positions of the luminescent wheel101. In association with this, in addition to a collective lens group111configured to collect light in the red wavelength range from the red light source device120and a collective lens115configured to collect light in the red wavelength range which passes through a transmitting area103bon the luminescent wheel101, a collective lens group111aconfigured to collect light in the blue wavelength range from the excitation light shining device700and a collective lens115aconfigured to collect light in the green wavelength range are disposed on a luminescent wheel device100, the light in the green wavelength range being luminescent light which is emitted from a back surface side of the luminescent wheel101as a result of a luminescent material being excited when light in the blue wavelength range from the excitation light shining device700is shined on a luminescent light emitting area102as excitation light.

A dichroic mirror146A is disposed on a side of the collective lens115awhich faces a left panel15. The dichroic mirror146A reflects light in the blue wavelength range and light in the green wavelength range and transmits light in the red wavelength range.

Consequently, the dichroic mirror146A reflects light in the blue wavelength range which passes through the diffuse transmitting area103aof the luminescent wheel101while being diffused and which is then emitted from the collective lens115aand light in the green wavelength range which is emitted from the collective lens115aas a result of a luminescent material in the luminescent light emitting area102being excited towards the back panel13, causing them to be incident on the collective lens173. Then, light in the red wavelength range emitted from the collective lens115is reflected towards the back panel13by the reflecting mirror147, passes through the dichroic mirror146A and is eventually incident on the collective lens173. In this way, the light in the red wavelength range, the light in the green wavelength range, and the light in the blue wavelength range are combined together on the same optical path at the collective lens173.

Third Embodiment

Next, a third embodiment of the present invention will be described based onFIG. 5. A projector10B according to this third embodiment differs from the projector10A according to the second embodiment in that the arrangement of the red light source device120shown inFIG. 4is changed. That is, a red right source device120according to this third embodiment is disposed in such a manner that light emitted therefrom does not pass through a luminescent wheel101and becomes substantially at right angles to light emitted from an excitation light shining device700.

As a result, the configuration of a luminescent wheel device100becomes the same as the configuration of the luminescent wheel device100according to the first embodiment shown inFIG. 2. That is, the luminescent wheel device100does not need the collective lens group111for collecting light in the red wavelength range from the red light source device120and the collective lens115for collecting light in the red wavelength range that passes through the transmitting area103bof the luminescent wheel101as shown inFIG. 4.

However, a collective lens group111afor collecting light in the blue wavelength range from an excitation light shining device700and a collecting lens115afor collecting light in the blue wavelength range and light in the green wavelength range which is luminescent light emitted from a back surface side of the luminescent wheel101as a result of a luminescent material in a luminescent light emitting area102being excited by the light in the blue wavelength range are arranged similarly to the arrangement in the second embodiment shown inFIG. 4.

Further, a dichroic mirror146A, which is configured to reflect light in the blue wavelength range and light in the green wavelength range and transmit light in the red wavelength range, is arranged similarly to the arrangement in the second embodiment shown inFIG. 4, that is, on a side of the collective lens115awhich faces a left panel115.

As a result of the configuration described above, when compared with the second embodiment shown inFIG. 4, the collective lens group111and the collective lens115become unnecessary. In addition, a reflecting mirror147for reflecting light in the red wavelength range like the reflecting mirror147provided in the first embodiment shown inFIG. 2and the second embodiment shown inFIG. 4also becomes unnecessary. As a result, the number of component parts can be reduced, whereby the projector can be made smaller in size.

While the embodiments of the present invention have been described heretofore, the present invention is not limited in any way by the embodiments, and hence, various modifications can be made thereto. For example, in the embodiments described heretofore, the red light emitting diode is used as the red light source121of the red light source device120; however, a red laser diode may be used. In this case, the transmitting area103of the luminescent wheel101can be formed of a diffuse plate (in other words, the transmitting area103can be formed only of the diffuse transmitting area103a). Then, since a laser beam can be shined on the transmitting area103which moves in the circumferential direction by rotationally driving the luminescent wheel101for a period of time during which light emitted from the red laser diode and light emitted from the blue laser diodes71are shined on the transmitting area103, speckle noise can be reduced. In addition, since both light in the red wavelength range and light in the blue wavelength range pass through the transmitting area103of the luminescent wheel101, the bright laser light sources can be made use of without disposing any exclusive diffuse plate for the excitation light shining device700or the red light source device120.

The luminescent light emitting area102of the luminescent wheel101may be a luminescent light emitting area102formed of a luminescent material configured to be excited by excitation light to thereby emit light in the red wavelength range. In this case, a green light source device including a green laser diode or a green light emitting diode can replace the red light source device120.

Thus, according to the embodiments of the present invention that have been described heretofore, the luminescent wheel101(a wheel) includes the luminescent light emitting area102(a wavelength transforming area) configured to receive light in the blue wavelength range which is emitted from the excitation light shining device700and is incident thereon from the front surface side, which is the first surface side, as excitation light, transform the light in the blue wavelength range so received into luminescent light and emit the luminescent light so transformed from the back surface side, which is the second surface side, and the transmitting area103configured to emit the light in the blue wavelength range which is incident thereon from the front surface side or light in the red wavelength range from the red light source device120from the back surface side, the luminescent light emitting area102and the transmitting area103being provided end to end in the circumferential direction. Then, the dichroic mirrors146,146A transmit one of light in the blue wavelength range and light in the red wavelength range and reflect the other.

As a result, since light can be configured so as to enter from the front surface side to be emitted towards the back surface side, compared with the configuration in which luminescent light is emitted to the front surface side and light source light, which also acts as excitation light, is emitted to the back surface side, the number of component parts of the optical element can be reduced, whereby the miniaturization of the light source unit60can be realized.

The transmitting area103includes the transmitting area103bconfigured to transmit light without diffusing it and the diffuse transmitting area103aconfigured to emit light while diffusing it, which are provided end to end in the circumferential direction. As a result, a configuration can be adopted in which one light source (for example, the red light source device120) is configured of a red light emitting diode so that light in the red wavelength range emitted therefrom passes through the transmitting area103b, and the other light source (for example, the excitation light shining device700) is configured of blue laser diodes71so that light in the blue wavelength range emitted therefrom passes through the diffuse transmitting area103awhile being diffused.

The transmitting area103may be made up of a diffuse transmitting area configured to transmit light while diffusing it. As a result, even in the case that a red laser diode for emitting laser light is also used for the red light source device120, a diffuse plate does not have to be prepared for each light source of laser light.

The dichroic mirror146is disposed on the front surface side, which is the first surface side, of the luminescent wheel101which faces the reflecting mirror147. As a result, providing a configuration will be sufficient in which the dichroic mirror146is disposed in the position where lights emitted from the excitation light shining device700and the red light source device120intersect each other and one set of optical elements such as a collective lens group111configured to shine light on the luminescent wheel101, a collective lens115configured to collect light emitted from the back surface side of the luminescent wheel101, and the like is prepared.

The dichroic mirror146A is disposed on the second surface side of the luminescent wheel101. As a result, the excitation light shining device700and the red light source device120can be disposed in such a manner that lights emitted from both the devices become parallel to each other.

The dichroic mirrors146,146A are configured to reflect light in the blue wavelength range and transmit light in the red wavelength range. As a result, the degree of freedom in laying out the excitation light shining device70for emitting light in the blue wavelength range and the red light source deice120for emitting light in the red wavelength range can be enhanced.

The reflecting mirror147(the total reflecting mirror) can be disposed on the second surface side of the luminescent wheel. As a result, the direction of the axis of light emitted from the luminescent wheel101can be changed.

The luminescent wheel101includes the luminescent light emitting area102configured to emit luminescent light. As a result, bright luminescent light can be made use of as a light source.

The filter, which is configured to transmit light in the blue wavelength range and reflect luminescent light, is provided on the first surface side of the luminescent light emitting area102. As a result, the efficiency of excitation of luminescent light by excitation light can be enhanced.

The projectors10,10A include the light source unit60, the display device51, the projection optical system220, and the projector control unit. As a result, it is possible to provide the projectors10,10A which are made small in size.

In the embodiments that have been described heretofore, the luminescent light emitting area employing the luminescent material is described as constituting the wavelength transforming area; however, the present invention is not limited to this configuration. A configuration may be adopted in which a wavelength transforming material, a wavelength transforming film, or the like is used in place of the luminescent material.

While the embodiments of the present invention have been described heretofore, the embodiments are presented as examples, and hence, there is no intention to limit the scope of the present invention by the embodiments. The novel embodiments can be carried out in other various forms, and various omissions, replacements and modifications can be made thereto without departing from the spirit and scope of the present invention. Those resulting embodiments and their modifications are included in the scope and gist of the present invention and are also included in the scope of inventions claimed for patent under claims below and their equivalents.