LIGHT SOURCE DEVICE, PROJECTION DISPLAY UNIT, AND DISPLAY SYSTEM

A light source device (10) of the invention includes: a light source (11) that emits a light beam in a first wavelength region; an optical path splitting element (12) that splits an optical path of the light beam in the first wavelength region emitted from the light source into a first optical path and a second optical path; a first fluorescent body (131a) that is disposed on the first optical path, and emits a light beam in a second wavelength region by undergoing excitation by the light beam in the first wavelength region, the second wavelength region differing from the first wavelength region; a second fluorescent body (131b) that is disposed on the second optical path, and emits a light beam in a third wavelength region by undergoing excitation by the light beam in the first wavelength region, the third wavelength region differing from the first and second wavelength regions; and an optical path synthesizing element (12) that synthesizes the light beam in the second wavelength region emitted from the first fluorescent body and the light beam in the third wavelength region emitted from the second fluorescent body.

TECHNICAL FIELD

The disclosure relates to: a light source device to be used as, for example an illumination in a projection display unit; a projection display unit; and a display system.

BACKGROUND ART

In recent years, a projector (projection display unit) uses a light source device (illumination device) that irradiates a fluorescent body with light from an individual light source, such as a laser, to output fluorescence light as illumination light. Further, by adopting a so-called reflective configuration in which a fluorescent body is formed on a metal or other reflective material, it becomes possible to obtain a high output.

Meanwhile, in the field of user interfaces (UIs), invisible light such as infrared light in addition to visible light may be used, in some cases, in an electronic apparatus that includes a projection display unit as described above. For example, PTL 1 suggests a light source device using a fluorescent body, in which a near infrared light source (LED) is disposed, in addition to a light source (blue laser) for excitation of the fluorescent body.

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

However, the light source device disclosed in PTL 1 may involve an increased number (or types) of light sources. In addition, there has been a demand that a cooling mechanism should be provided for each light source. For this reason, it is difficult to allow the entire device to have a smaller size.

It is therefore desirable to provide: a light source device that makes it possible to achieve a simple and compact configuration in which a fluorescent body is used; and a projection display unit and a display system, each of which uses such a light source device.

A light source device according to an embodiment of the disclosure includes: a light source that emits a light beam in a first wavelength region; an optical path splitting element that splits an optical path of the light beam in the first wavelength region emitted from the light source into a first optical path and a second optical path; a first fluorescent body that is disposed on the first optical path, and emits a light beam in a second wavelength region by undergoing excitation by the light beam in the first wavelength region, the second wavelength region differing from the first wavelength region; a second fluorescent body that is disposed on the second optical path, and emits a light beam in a third wavelength region by undergoing excitation by the light beam in the first wavelength region, the third wavelength region differing from the first and second wavelength regions; and an optical path synthesizing element that synthesizes the light beam in the second wavelength region emitted from the first fluorescent body and the light beam in the third wavelength region emitted from the second fluorescent body.

A projection display unit according to an embodiment of the disclosure includes the above-described light source device according to the embodiment of the disclosure.

A display system according to an embodiment of the disclosure includes the above-described projection display unit according to the embodiment of the disclosure.

In the light source device, the projection display unit, and the display system according to the embodiments of the disclosure, the light source emits the light beam in the first wavelength region, and then the optical path splitting element splits the light beam into first and second optical paths. On the first optical path, the first fluorescent body generates fluorescence (emits fluorescence light) using the light beam in the first wavelength region as an excitation light beam, thereby emitting the light beam in the second wavelength region. On the second optical path, the second fluorescent body generates fluorescence using the light beam in the first wavelength region as an excitation light beam, thereby emitting the light beam in the third wavelength region. Then, the optical path synthesizing element synthesizes the light beams in the second and third wavelength regions that have been emitted to the respective optical paths, and outputs the synthesized light beam.

According to the light source device, the projection display unit, and the display system according to the embodiments of the disclosure, the light source emits the light beam in the first wavelength region, and then the optical path splitting element splits the light beam into first and second optical paths. On the first optical path, the first fluorescent body is used to emit the light beam in the second wavelength region. On the second optical path, the second fluorescent body is used to emit the light beam in the third wavelength region. Then, the optical path synthesizing element synthesizes the light beams in the second and third wavelength regions, and outputs the synthesized light beam. In this way, it is possible to output light beams in a plurality of wavelength regions by using a light source in a single wavelength region. It is possible to reduce the number (types) of light sources compared to a case where light sources for a plurality of different wavelength regions are arranged, thus allowing for reduction of cooling mechanisms. Consequently, it is possible to achieve a simple and compact device configuration in which a fluorescent body is used.

It is to noted that mere examples of the disclosure are described above. Effects of the disclosure are not limited to those described above, and may be other effects, or may further include other effects.

MODES FOR CARRYING OUT THE INVENTION

Some embodiments of the disclosure are described below in detail with reference to the accompanying drawings. It is to be noted that the description is given in the following order.

1. First embodiment (an example of a light source device in which an optical path of a light beam emitted from a light source unit is split into multiple optical paths, then the wavelengths of the light beams on the respective optical paths are converted, after which the light beams are synthesized and outputted)

2. Second embodiment (an example of a light source device in which an optical path of a light beam emitted from a light source unit is split into multiple optical paths with the use of polarization, then the wavelengths of the light beams on the respective optical paths are converted, after which the optical paths are synthesized and outputted)

3. Modification Example 1 (an example in which two types of fluorescent bodies are held by a single rotating body)

4. Modification Example 2 (an example of a case where transmission type wavelength converters are used)

5. Modification Example 3 (an example of a case where a transmission type wavelength converter is used)

6. Application Example 1 (an example of a projection display unit)

7. Application Examples 2 and 3 (an example of a display system)

FIG. 1illustrates a configuration example of a light source device (a light source device10) according to a first embodiment of the disclosure. The light source device10is used as, for example, an illumination in a projection display unit (a projector) described later.

The light source device10includes: a light source unit11A that includes a light source11; an optical path splitting/synthesizing element12; and wavelength converters13A and13B, for example. Lenses121and122are disposed in the light source unit11A. A lens123is disposed between the optical path splitting/synthesizing element12and the wavelength converter13A. A lens124is disposed between the optical path splitting/synthesizing element12and the wavelength converter13B.

The light source11is a light source that emits a light beam in a wavelength region W1(a first wavelength region). For example, the light source11may include a semiconductor laser (LD) or a light-emitting diode (LED). The light source11is an excitation light source for respective fluorescent bodies (fluorescent bodies131aand131bdescribed later) in the wavelength converters13A and13B. The light source11emits a light beam in the wavelength region W1, such as a light beam in a blue light region, namely, a blue light beam. It is to be noted that the light beam in the wavelength region W1as used herein refers to a light beam having an emission intensity peak in the wavelength region W1.

The optical path splitting/synthesizing element12is an element that splits an optical path of a light beam (L1) in the wavelength region W1emitted from the light source unit11A by transmitting a portion of the light beam L1and reflecting the remaining portion, and synthesizes light beams with converted wavelengths (a light beam L2in a wavelength region W2and a light beam L3in a wavelength region W3). The optical path splitting/synthesizing element12is configured by a dichroic mirror, for example, and is positioned with its plane of incidence or reflection forming an angle of 45 degrees with its incident optical path, for example. It is to be noted that the optical path splitting/synthesizing element12may be an element that has the functions of both an “optical path splitting element” and an “optical path synthesizing element” of the disclosure. In other words, in this configuration example, the “optical path splitting element” also serves as the “optical path synthesizing element”. Further, the optical path splitting/synthesizing element12is not limited to the dichroic mirror. Alternatively, the optical path splitting/synthesizing element12may be configured by a dichroic prism.

In the present embodiment, for example, the optical path splitting/synthesizing element12is configured to split the optical path of the incoming light beam L1into an optical path (first optical path) extending in a travel direction of the light beam L1(negative direction of the X axis) and an optical path (second optical path) extending in a direction perpendicular to the travel direction of the light beam L1(positive direction of the Y axis). InFIG. 1, a light beam of the light beam L1which passes through the optical path splitting/synthesizing element12(light traveling in the negative direction of the X axis) is depicted as a light beam L11. A light beam of the light beam L1which is reflected by the optical path splitting/synthesizing element12(light traveling in the positive direction of the Y axis) is depicted as a light beam L12. Furthermore, the optical path splitting/synthesizing element12is configured to synthesize the light beam L2in the wavelength region W2and the light beam L3in the wavelength region W3and to emit the synthesized light beam (in the same direction). The synthesized light beam of these light beams L2and L3constitutes an output of the light source device10.

FIG. 2illustrates examples of wavelength regions W1to W3. As illustrated, for example, the wavelength region W1is a blue light region; the wavelength region W2is a wavelength region covering a green light region and a red light region, namely, a yellow wavelength region; and the wavelength region W3is an infrared region or a near infrared region. In this case, a blue laser is used as the light source11, and the emission intensity of the light beam L1has a peak in the wavelength region W1. The wavelength region W1ranges from 430 nm to 480 nm, for example. The wavelength region W2ranges from 480 nm to 700 nm, for example. The wavelength region W3ranges from 700 nm to 2000 nm, for example.

An example of a combination of the wavelength regions W1to W3is described below in Table 1. It is to be noted that Example 1 in Table 1 corresponds to the combination of the wavelength regions W1to W3in the present embodiment.

As in Example 2 in Table 1, the wavelength region W1of the light beam, i.e., the excitation light beam, emitted from the light source11is not limited to the blue light region, and may be an ultraviolet region, such as a wavelength region ranging from 300 nm to 430 nm. In this case, for example, an ultraviolet (UV) laser may be used as the light source11. As in Examples 3 and 4, the wavelength region W2may be a green light region, such as a wavelength region ranging from 480 nm to 590 nm, and the wavelength region W3may be a red light region, such as a wavelength region ranging from 580 nm to 700 nm. Further, as in Example 5, the wavelength region W1may be an ultraviolet region, the wavelength region W2may be a wavelength region covering a green light region and a red light region, and the wavelength region W3may be a blue light region. In addition, as in Example 6, the wavelength region W1may be a blue light region, the wavelength region W2may be a wavelength region covering a green light region and a red light region, and the wavelength region W3may be a red light region.

As described above, the combination of the wavelength regions W1to W3is not especially limiting, and may take various forms of combination depending on applications. As in Examples 1 and 2, for example, the wavelength region W3is set to be an infrared region for special displaying applications, such as a night vision device or applications other than displaying, such as sensing. As in Examples 3 to 6, alternatively, each of the wavelength regions W2and W3may be set to be a combination of wavelength regions within a visible region for applications in which a color purity of illumination light is enhanced or a shade is added to illumination light.

FIG. 3illustrates an example of optical characteristics of the optical path splitting/synthesizing element12, i.e., transmittances in the wavelength regions W1to W3. The optical path splitting/synthesizing element12is designed such that its transmittances (reflectances) in wavelength regions W1to W3, as described above, differ from one another. For example, the optical path splitting/synthesizing element12is designed such that: its transmittance (reflectance) in the wavelength region W1becomes a % (100−a) %; its transmittance (reflectance) in the wavelength region W2becomes substantially 0% (substantially 100%); and its transmittance (reflectance) in the wavelength region W3becomes substantially 100% (substantially 0%). By adjusting transmittance “a” in the wavelength region W1, it is possible to: flexibly set a ratio of a transmission amount to a reflection amount of the optical path splitting/synthesizing element12(a split or distribution ratio of the light beam L11to the light beam L12of the light beam L1), i.e., an intensity ratio of light beam L2in the wavelength region W2to the light beam L3in the wavelength region W3, depending on applications. In some layouts of the optical system, the transmittance in the wavelength region W2is set to substantially 100%, and the transmittance in the wavelength region W3is set to substantially 0%. In other words, the optical path splitting/synthesizing element12may transmit one of the light beams in the wavelength regions W2and W3, and reflect the other.

Each of the wavelength converters13A and13B is an element that has a function of converting the wavelength region W1of an incoming light beam into the wavelength region W2or W3. In the present embodiment, both of the wavelength converters13A and13B employ a so-called reflective type which reflects fluorescent beams generated in response to entry of excitation light beams to output the reflected fluorescent beams.

The wavelength converter13A is provided with the fluorescent body131athat uses the light beam L11in the wavelength region W1as its excitation light and generates a fluorescent beam in the wavelength region W2. The fluorescent body131ais held by a rotating body132(wheel) that has a disc shape, for example, and is disposed so as to at least partly face the optical path of the light beam L11, i.e., the first optical path. For example, the fluorescent body131ain powder, glass, or crystalline form may be used. The rotating body132is coupled to a motor133(driver), and is rotatable around an axis A1by means of driving power from the motor133. In the rotating body132, the fluorescent body131ais held over a reflective member (plane of reflection). For example, the fluorescent body131ais formed, on the rotating body132, into a ring, arc, or disc shape, for example, with the axis A1as the center. In this configuration, the motor133drives the rotating body132to rotate, thus causing the light beam L11to be partly incident on the fluorescent body131ain a circulating manner. It is to be noted that the wavelength converter13A may be provided with an unillustrated cooling mechanism.

The wavelength converter13B is provided with the fluorescent body131bthat uses the light beam L12in the wavelength region W1as its excitation light and generates a fluorescent beam in the wavelength region W3. The fluorescent body131bis held by a rotating body132and disposed so as to at least partially face the optical path of the light beam L12, i.e., the second optical path. For example, the fluorescent body131bin powder, glass, or crystalline form may be used. The rotating body132is rotatable around an axis A2by means of driving power from a motor133. In the rotating body132, the fluorescent body131bis held over a reflective member. The fluorescent body131bis formed, on the rotating body132, in a ring, arc, or disc shape, for example, with the axis A2as the center. In this configuration, the motor133drives the rotating body132to rotate, thus causing the light beam L12to be partly incident on the fluorescent body131bin a circulating manner. It is to be noted that the wavelength converter13B may be provided with an unillustrated cooling mechanism.

It is to be noted that, in this example, the fluorescent bodies131aand131bare held by the respective rotating bodies132in the wavelength converters13A and13B. However, depending on exciting energy for the fluorescent bodies131aand131b,the rotating body132does not necessarily have to be provided. In other words, the fluorescent bodies131aand131bdoes not necessarily have to be rotated. In this case, the fluorescent bodies131aand131bmay be simply disposed on the optical paths of the light beams L11and L12, respectively.

The lenses121and122constitute a lens group that focuses the light beam L1emitted from the light source11and causes the light beam L1to be incident on the optical path splitting/synthesizing element12. In this case, the two lenses121and122in the light source unit11A are depicted. However, alternatively, a single lens or three or more lenses may be used. These lenses121and122guide the light beams L2and L3emitted, respectively, from the fluorescent bodies131aand131bto the optical path splitting/synthesizing element12.

The lens123focuses light, i.e., the light beam L11, emitted from the optical path splitting/synthesizing element12and causes the light beam L11to be incident on the fluorescent body131a.In addition, the lens123guides light, i.e., the light beam L2with a converted wavelength emitted from the fluorescent body131ato the optical path splitting/synthesizing element12. The lens124focuses light, i.e., the light beam L12, emitted from the optical path splitting/synthesizing element12and causes the light beam L12to be incident on the fluorescent body131b. In addition, the lens124guides light, i.e., the light beam L3with a converted wavelength, emitted from the fluorescent body131bto the optical path splitting/synthesizing element12.

In the light source device10in the present embodiment, when the light source11is driven and the light source unit11A emits the light beam L1in the wavelength region W1, this light beam L1is incident on the optical path splitting/synthesizing element12. Due to the optical characteristics illustrated inFIG. 3, the optical path splitting/synthesizing element12transmits a portion (light beam L11) of the light beam L1in the wavelength region W1, and reflects the remaining portion (light beam L12. In this way, the optical path of the light beam L1in the wavelength region W1is split into the optical paths of the light beams L11and L12.

After having passed through the optical path splitting/synthesizing element12, the light beam L11is focused, by the lens123, on the fluorescent body131ain the wavelength converter13A. As a result, the fluorescent body131ais excited by the light beam L11in the blue light region, for example, to generate fluorescence of the light beam L2in the wavelength region W2covering the green and red light regions, for example. This light beam L2with a converted wavelength is reflected on the rotating body132, and enters the lens123again. Then, the light beam L2is converted by the lens123into a parallel light beam, and is incident on the optical path splitting/synthesizing element12.

After having been reflected by the optical path splitting/synthesizing element12, the light beam L12is focused, by the lens124, on the fluorescent body131bin the wavelength converter13B. As a result, the fluorescent body131bis excited by the light beam L12in the blue light region, for example, thus generating fluorescence of the light beam L3in the wavelength region W3, such as the infrared region. This light beam L3with a converted wavelength is reflected by the rotating body132, and enters the lens124again. Then, the light beam L3is converted by the lens124into a parallel light beam and is incident on the optical path splitting/synthesizing element12.

Due to the optical characteristics as illustrated inFIG. 3, when both the light beam L2in the wavelength region W2and the light beam L3in the wavelength region W3are incident on the optical path splitting/synthesizing element12, the optical path splitting/synthesizing element12reflects the light beam L2and transmits the light beam L3. As a result, the optical paths of the light beams L2and L3are synthesized. In other words, the colors of the light beams L2and L3are synthesized. The synthesized light beam of the light beams L2and L3constitutes an output of the light source device10.

Here,FIG. 4illustrates an example of a light source device that uses a fluorescent body, as a comparative example (Comparative Example 1) of the present embodiment. The light source device in Comparative Example 1 includes: a light source101that emits a light beam (a light beam L101) in the wavelength region W1; a dichroic mirror102; a lens103; and a wavelength converter104. The dichroic mirror102is designed so as to, for example, reflect the wavelength region W2, while transmitting the wavelength region W1. The wavelength converter104includes a fluorescent body1041, a rotating body1042, and a motor1043. In Comparative Example 1, the light beam L101emitted from the light source101passes through the dichroic mirror102, and then is focused on the fluorescent body1041by the lens103. The fluorescent body1041is excited by the light beam L101, thus generating fluorescence of a light beam L102in the wavelength region W2, which is reflected to the lens103. The light beam L102passes through the lens103, and is incident on the dichroic mirror102. The light beam L102in the wavelength region W2is reflected by the dichroic mirror102.

Further,FIG. 5illustrates another example of the light source device that uses the fluorescent body, as a comparative example (Comparative Example 2) of the present embodiment. As in Comparative Example 1 described above, the light source device in Comparative Example 2 includes the light source101, the dichroic mirror102, the lens103, and the wavelength converter104. In Comparative Example 2, however, the light source device further includes a light source105that emits a light beam in the wavelength region W3, such as infrared light. A lens106is disposed between the light source105and the dichroic mirror102. Further, the dichroic mirror102is designed so as to, for example, reflect the wavelength region W2, while transmitting the wavelength regions W1and W3. In this configuration, in Comparative Example 2, the light beam L101emitted from the light source101passes through the dichroic mirror102, and then is focused on the fluorescent body1041, as in Comparative Example 1 described above. The fluorescent body1041is thereby excited by the light beam L101, thus generating fluorescence of the light beam L102in the wavelength region W2. This light beam L102is incident on the dichroic mirror102again through the lens103, and is reflected by this dichroic mirror102. A light beam L103in the wavelength region W3emitted from the light source105is incident on the dichroic mirror102through the lens106, and passes through the dichroic mirror102. In this way, the light beam L102in the wavelength region W2and the light beam L103in the wavelength region W3are synthesized and outputted from the light source device10.

In each of Comparative Examples 1 and 2, the dichroic mirror102ideally transmits 100% of the light beam L101in the wavelength region W1. In fact, however, it is difficult to maintain a characteristic of transmitting (or reflecting) 100% of light, because a transmission characteristic of the dichroic mirror102exhibits incident angle dependency and because a design is restricted by a manufacturing process. As illustrated inFIG. 6, for example, the transmittance of the dichroic mirror102at a wavelength varies depending on an incident angle. It is appreciated that the transmission characteristic acquired when light enters the plane of incidence or reflection of the dichroic mirror102at an angle of 45 degrees is different from that acquired when light enters the plane of incidence or reflection at an angle of (45+12) or (45−12) degrees. In this way, in fact, the light beam L101in the wavelength region W1that is to enter the dichroic mirror102includes light (leaked light X1) that does not pass through the dichroic mirror102but is reflected thereby. This results in lowered efficiency of light utilization.

In Comparative Example 2, this leaked light X1enters the light source105such as an LED, thereby possibly damaging and degrading the light source105. This may also cause an increase in temperature of the light source105, thereby lowering its light emission efficiency. Furthermore, in a case of outputting light beams in a plurality of wavelength regions, including an infrared region, as in Comparative Example 2, when two or more types of light sources101and105are used, it is desirable that a cooling mechanism be provided for each light source due to increased number (or types) of light sources. Therefore, it is difficult to allow the entire device to have a smaller size.

In contrast, in the present embodiment, the optical path splitting/synthesizing element12splits the optical path of the light beam L1in the wavelength region W1emitted from the light source11(light source unit11A). On the first optical path, which is one of the split optical paths, the fluorescent body131auses the light beam L1in the wavelength region W1as an excitation light beam to generate fluorescence (generate fluorescence emission), thus emitting the light beam L2in the wavelength region W2. On the second optical path, which is the other of the split optical paths, the fluorescent body131buses the light beam L1in the wavelength region W1as an excitation light beam to generate fluorescence, thus emitting the light beam L3in the wavelength region W3. The optical path splitting/synthesizing element12synthesizes the light beam L2in the wavelength region W2and the light beam L3in the wavelength region W3that have been emitted to the respective paths, and the light source device10outputs the synthesized light beam to its outside. In other words, it is possible to use the light source11that emits the light beam L1in a single wavelength region (wavelength region W1) to synthesize light beams in a plurality of wavelength regions (wavelength regions W2and W3) and output the synthesized light beam.

The foregoing embodiment makes it possible to use the light source11that emits the light beam L1in the single wavelength region W1to generate light beams in a plurality of wavelength regions (wavelength regions W2and W3). It is possible to reduce the number of light sources compared to a case where (a plurality of types of) light sources for a plurality of different wavelength regions are arranged (as in Comparative Example 2), thus allowing for reduction of cooling mechanisms. Consequently, it is possible to achieve a simple and compact device configuration in which a fluorescent body is used.

Further, by adjusting a ratio of the transmittance (to the reflectance) of the optical path splitting/synthesizing element12, it is possible to efficiently utilize not only transmitted light but also reflected light. This makes it possible to reduce an optical loss that is caused by the leaked light X1, unlike Comparative Examples 1 and 2, thereby controlling lowering of efficiency of light utilization. In addition, allowing for reduction of the number (or types) of light sources also leads to cost reduction.

Furthermore, by controlling the transmittance in the wavelength region W1in the optical path splitting/synthesizing element12, it is possible to adjust a distribution ratio between the wavelength regions W2and W3. This enables various combinations of the wavelength regions W1to W3to be selected depending on applications. For example, it is possible to output rays having a color balance in accordance with a display image, as illumination light. In this case, by controlling the transmittance of the optical path splitting/synthesizing element12, it is possible to set an appropriate color balance, thereby making it unnecessary to perform a gray-scale adjustment of an output of a display device. This makes unwanted rays less likely to enter the display device, thereby controlling a temperature rise of the display device (panel) and thus improving its reliability. The light source device10is also applicable to a night vision application in which the percentage of infrared light is larger than that of visible light.

Next, description is given of some embodiments and modification examples that are different from the foregoing first embodiment. In the following, same components as those of the foregoing first embodiment are provided with the same reference numerals as those of the foregoing first embodiment, and description thereof is omitted as appropriate.

Second Embodiment

FIG. 7illustrates a configuration example of a light source device (a light source device20) according to a second embodiment of the disclosure. Similarly to the light source device10in the foregoing first embodiment, the light source device20is used as an illumination in a projection display unit described later. This light source device20includes: a light source unit11A that includes a light source11; a wave plate14(polarization rotating element); an optical path splitting/synthesizing element15; wavelength converters13A and13B; and lenses123and124, for example.

The light source unit11A includes the light source11(which is not illustrated inFIG. 7) that emits a light beam in the wavelength region W1(first wavelength region), and lenses121and122, similarly to the foregoing first embodiment. In the present embodiment, however, as the light source11, a light source is used that exhibits a linearly polarized light characteristic (emits a linearly polarized light beam), such as that of a semiconductor laser. It is to be noted that, in the light source unit11A, the light source11may be disposed so as to be rotatable around its optical axis. In this case, it is possible to cause the light source11to emit a light beam with its polarization direction of the light beam L1rotating without disposing the wave plate14described later.

The wave plate14alters or rotates a polarization direction of the light beam L1, which is a linearly polarized light beam, emitted from the light source unit11A. The wave plate14includes a half-wave plate, for example. This wave plate14is disposed with its optical axis (slow axis or fast axis) inclined at a predetermined angle with respect to the polarization direction of the light beam L1in a YZ plane. Specifically, the wave plate14is disposed such that the polarization direction of the light beam L1to be incident on the optical path splitting/synthesizing element15is inclined at a predetermined angle, such as 45 degrees, with respect to a Z axis. Using the wave plate14makes it possible to adjust an inclination angle of the polarization direction of the light beam L1, thereby appropriately setting a ratio (splitting ratio) of the transmission amount of an s polarization component to the reflection amount of a p polarization component in the optical path splitting/synthesizing element15. A drive mechanism that rotates the wave plate14around the optical axis may be provided. This drive mechanism may be used to automatically or manually control an orientation of the light beam L1in the polarization direction. It is also possible to further provide a function of manually or automatically varying the splitting ratio of the p polarization component to the s polarization component in the optical path splitting/synthesizing element15(in accordance with an image to be displayed or projected, for example).

Similar to the optical path splitting/synthesizing element12in the foregoing first embodiment, the optical path splitting/synthesizing element15is an element that splits the optical path of the light beam L1in the wavelength region W1emitted from the light source unit11A, and synthesizes light beams with converted wavelengths, i.e., the light beam L2in the wavelength region W2and the light beam L3in the wavelength region W3. The optical path splitting/synthesizing element15is configured by a dichroic mirror, for example, and is disposed with its plane of incidence or reflection forming an angle of 45 degrees with respect to an X axis, for example. It is to be noted that the optical path splitting/synthesizing element15is not limited to a dichroic mirror. Alternatively, the optical path splitting/synthesizing element15may be configured by a dichroic prism or a polarization beam splitter (PBS).

In the present embodiment, however, the optical path splitting/synthesizing element15has a configuration in which a transmission characteristic (or reflection characteristic) varies in accordance with a polarization component. InFIG. 7, a first polarization component, such as a p polarization component, of the light beam L1which passes through the optical path splitting/synthesizing element15is depicted as a light beam L11p,and a second polarization component, such as an s polarization component, of the light beam L1which is reflected by the optical path splitting/synthesizing element15is depicted as a light beam L12s.In addition, the optical path splitting/synthesizing element15is configured to synthesize the light beam L2pin the wavelength region W2and the light beam L3sin the wavelength region W3and to emit the synthesized light beam (in the same direction). The synthesized light beam of the light beams L2pand L3sconstitutes an output of the light source device20.

FIG. 8illustrates an example of optical characteristics (transmittances for s and p polarization components in each of the wavelength regions W1to W3) of the optical path splitting/synthesizing element15. The optical path splitting/synthesizing element15is designed such that its transmittance (reflectance) for a p polarization component (solid line) and for an s polarization component (broken line) vary in the wavelength regions W1to W3. For example, the transmittance for the p polarization component becomes substantially 100% (reflectance becomes substantially 0%) at least in a wavelength region corresponding to the light beam L1of the wavelength region W1. In contrast, the transmittance for the s polarization component becomes substantially 0% (reflectance becomes substantially 100%). By adjusting an inclination angle of the polarization direction of the light beam L1to be incident on the optical path splitting/synthesizing element15that exhibits the above characteristic, it is possible to appropriately set a ratio of a transmission amount for an s polarization component to a reflection amount for a p polarization component. For example, in a case where the polarization direction of the incident light beam L1is inclined at an angle of 45 degrees with respect to the Z axis, the transmission amount for an s polarization component in the light beam L1and the reflection amount for a p polarization component in the light beam L1are both set to a half (substantially 50% each).

Meanwhile, the transmittances for the p and s polarization components each become substantially 0% (reflectances become substantially 100%) in the wavelength region W2. The transmittances for the p and s polarization components each become substantially 100% (reflectances become substantially 0%) in the wavelength region W3. In this way, by setting the optical path splitting/synthesizing element15such that its transmittance in the wavelength region W1varies in accordance with a polarization component, it is possible to split the optical path of the light beam L1in the wavelength region W1.

In the light source device20in the present embodiment, the light source unit11A emits the light beam L1in the wavelength region W1, which is a linearly polarized light beam, and then the light beam L1enters the wave plate14. This wave plate14rotates the polarization direction of the light beam L1so that the polarization direction is inclined at a predetermined angle, and then outputs the light beam L1. The light beam L1having been emitted from the wave plate14is incident on the optical path splitting/synthesizing element15, and the p polarization component, namely, the light beam L11pin the light beam L1passes through the optical path splitting/synthesizing element15, whereas the s polarization component, namely, the light beam L12sin the light beam L1is reflected by the optical path splitting/synthesizing element15. In this way, the optical path of the light beam L1is split.

When the light beam L11p,i.e., a p polarization, having passed through the optical path splitting/synthesizing element15is focused, by the lens123, on a fluorescent body131aof a wavelength converter13A, the light beam L2p,i.e., a p polarization, in the wavelength region W2is generated due to fluorescent emission. This light beam L2pwith a converted wavelength is reflected on a rotating body132, and is incident on the optical path splitting/synthesizing element15through the lens123.

Meanwhile, when the light beam L12s,i.e., an s polarization having been reflected by the optical path splitting/synthesizing element15is focused, by the lens124, on a fluorescent body131bof the wavelength converter13B, the light beam L3s,i.e., an s polarization, in the wavelength region W3is generated due to fluorescent emission. This light beam L3swith a converted wavelength is reflected on a rotating body132, and is incident on the optical path splitting/synthesizing element15through the lens124.

In this way, when the light beams L2pand L3sare incident on the optical path splitting/synthesizing element15, the light beam L2p,i.e., the p polarization, in the wavelength region W2is reflected by the optical path splitting/synthesizing element15, whereas the light beam L3s,i.e., the s polarization, in the wavelength region W3passes through the optical path splitting/synthesizing element15, due to the optical characteristics illustrated inFIG. 8. As a result, the optical paths of the light beams L2pand L3sare synthesized. In other words, the colors of the light beams L2pand L3sare synthesized. The synthesized light beam of the light beams L2pand L3sconstitutes an output of the light source device20.

As described above, the light source device20in the present embodiment also makes it possible to use the light source11(light source unit11A) which emits the light beam L1in a single wavelength region, i.e., the wavelength region W1, to synthesize light beams in a plurality of wavelength regions (wavelength regions W2and W3) and output the synthesized light beam. Consequently, it is possible to achieve effects similar to those of the foregoing first embodiment.

Modification Example 1

FIG. 9illustrates a configuration example of a light source device (a light source device10A) according to Modification Example 1. The light source device10A includes a light source unit11A, an optical path splitting/synthesizing element12, a wavelength converter13C, lenses123and124, and an optical path changing element125, for example. In the wavelength converter13C of the present modification example, a fluorescent body131athat converts from the wavelength region W1to the wavelength region W2and a fluorescent body131bthat converts from the wavelength region W1to the wavelength region W3are held by the same rotating body (a rotating body134).

The wavelength converter13C is an element that has a function of converting the wavelength region W1of an incident light beam into the wavelength regions W2and W3, similarly to the wavelength converters13A and13B in the foregoing first embodiment. However, the wavelength converter13C of the present modification example holds both the fluorescent bodies131aand131bon the rotating body134(wheel), with the plane of reflection therebetween.

The fluorescent bodies131aand131bare each formed, on the rotating body134, into a ring shape, for example, with an axis A3as each center, and are disposed concentrically. Each of the fluorescent bodies131aand131bare. The fluorescent body131ais disposed so as to at least partly face an optical path (first optical path) of a light beam L11while being held by the rotating body134. The fluorescent body131bis disposed so as to at least partly face an optical path (second optical path) of a light beam L12while being held by the rotating body134. The rotating body134is coupled to a motor135(driver), and thus is rotatable around the axis A3by means of driving power from the motor135. In this configuration, the motor135drives the rotating body134to rotate, thus causing the light beam L11to be partly incident on the fluorescent body131ain a circulating manner, whereas light beam L12is partly incident on the fluorescent body131bin a circulating manner. It is to be noted that an unillustrated cooling mechanism may be disposed on the wavelength converter13C.

The optical path changing element125is configured by a mirror, for example, and converts an optical path of the split light beam L12reflected (split) by the optical path splitting/synthesizing element12and causes the light beam L12to be incident on the fluorescent body131bof the wavelength converter13C.

Also in the present modification example, similarly to the foregoing first embodiment, a portion (light beam L11) of the light beam L1in the wavelength region W1emitted from the light source unit11A passes through the optical path splitting/synthesizing element12, whereas the remaining portion (light beam L12) is reflected by the optical path splitting/synthesizing element12, so that the optical path is split. When the light beam L11having passed through the optical path splitting/synthesizing element12is focused, by the lens123, on the fluorescent body131ain the wavelength converter13C, the light beam L2in the wavelength region W2is generated due to fluorescent emission. The light beam L2with a converted wavelength is reflected on the rotating body134, and is incident on the optical path splitting/synthesizing element12through the lens123. In contrast, after the light beam L12reflected by the optical path splitting/synthesizing element12undergoes an optical path change by the optical path changing element125, the light beam L12is focused, by the lens124, on the fluorescent body131bin the wavelength converter13C, thus generating the light beam L3in the wavelength region W3due to fluorescent emission. This light beam L3with a converted wavelength is reflected on the rotating body134, and then is incident on the optical path splitting/synthesizing element12through the lens124and the optical path changing element125. The light beam L2in the wavelength region W2is reflected by the optical path splitting/synthesizing element12, whereas the light beam L3in the wavelength region W3passes through the optical path splitting/synthesizing element12, similarly to in the foregoing first embodiment. As a result, the optical paths of the light beams L2and L3are synthesized. In other words, the colors of the light beams L2and L3are synthesized. The synthesized light beam of the light beams L2and L3constitutes an output of the light source device10A.

In this way, also in the present modification example, it is possible to use the light source11(light source unit11A) which emits the light beam L1in a single wavelength region, i.e., in the wavelength region W1, to synthesize light beams in a plurality of wavelength regions, i.e., in the wavelength regions W2and W3, and output the synthesized light beam. Consequently, it is possible to achieve effects similar to those of the foregoing first embodiment.

Modification Example 2

FIG. 10illustrates a configuration example of a light source device (a light source device10B) according to Modification Example 2. The light source device10B includes a light source unit11A, an optical path splitting element16A, wavelength converters17A and17B, lenses123and124, optical path changing elements126aand126b,and an optical path synthesizing element16B, for example. In the present modification example, unlike the foregoing first embodiment, both of the wavelength converters17A and17B employ the so-called transmission type which transmits fluorescent beams generated in response to the entry of excitation light beams to output the transmitted fluorescent beams. In the foregoing first embodiment, the optical path splitting/synthesizing element12has both functions of splitting an optical path and synthesizing the optical paths. In the present modification example, however, the optical path splitting element16A and the optical path synthesizing element16B are disposed at different locations as separate members.

The optical path splitting element16A is an element that splits an optical path of the light beam L1in the wavelength region W1emitted from the light source unit11A. The optical path splitting element16A transmits a portion of the light beam L1in the wavelength region W1, and reflects the remaining portion, similarly to the optical path splitting/synthesizing element12in the foregoing first embodiment. The optical path splitting element16A is configured by a dichroic mirror, for example, and is disposed with its plane of incidence or reflection forming an angle of 45 degrees with respect to an X axis, for example. It is to be noted that the optical path splitting/synthesizing element15is not limited to a dichroic mirror, and may be configured by a dichroic prism. InFIG. 10, a light beam of the light beam L1which passes through the optical path splitting element16A (light beam traveling in the negative direction of a Y axis) is depicted as a light beam L11. A light beam of the light beam L1which is reflected by the optical path splitting element16A (light beam traveling in the negative direction of the X axis) is depicted as a light beam L12.

The wavelength converter17A is an element that has a function of converting the wavelength region W1of the incident light beam into the wavelength region W2, similarly to the wavelength converter13A in the foregoing first embodiment. In the wavelength converter17A, a rotating body172holds a fluorescent body171athereon, and the fluorescent body171agenerates a fluorescent beam, which then passes through the rotating body172. The fluorescent body171ais formed into a ring, arc, or disc shape, for example, around an axis A4, similarly to the fluorescent body131ain the foregoing first embodiment. Further, the fluorescent body171ais disposed so as to at least partly face an optical path of the light beam L11(first optical path) while being held by the rotating body172. For example, a fluorescent body in powder, glass, or crystalline form may be used as the fluorescent body171a.The rotating body172is coupled to a motor173(driver), and thus is rotatable around the axis A4by means of driving power from the motor173. In this configuration, the motor173drives the rotating body172to rotate, thus causing the light beam L11to be partly incident on the fluorescent body171ain a circulating manner. It is to be noted that an unillustrated cooling mechanism may be disposed on the wavelength converter17A.

The wavelength converter17B is an element that has a function of converting the wavelength region W1of an incident light beam into the wavelength region W3, similarly to the wavelength converter13B in the foregoing first embodiment. In the wavelength converter17B, the rotating body172holds a fluorescent body171bthereon, and the fluorescent body171bgenerates a fluorescent beam, which then passes through the rotating body172. The fluorescent body171bis formed into a ring, arc, or disc shape around an axis A5, similarly to the fluorescent body131bin the foregoing first embodiment. Further, the fluorescent body171bis disposed so as to at least partly face an optical path (second optical path) of the light beam L12while being held by the rotating body172. For example, a fluorescent body in powder, glass, or crystalline form may be used as the fluorescent body171b.The rotating body172is rotatable around the axis A5by means of driving power from the motor173. In this configuration, the motor173drives the rotating body172to rotate, thus causing the light beam L12to be partly incident on the fluorescent body171bin a circulating manner. It is to be noted that an unillustrated cooling mechanism may be disposed on the wavelength converter17B.

Each of the optical path changing elements126aand126bis configured by a mirror, for example. The optical path changing element126achanges an optical path of the light beam L2(with a converted wavelength) which has passed through the wavelength converter17A, and then causes the light beam L2to be incident on the optical path synthesizing element16B. The optical path changing element126bconverts an optical path of the light beam L3(with a converted wavelength) which has passed through the wavelength converter17B, and then causes the light beam L3to be incident on the optical path synthesizing element16B.

The optical path synthesizing element16B synthesizes the optical paths of the light beams L2and L3in the respective wavelength regions W2and W3which have undergone an optical path change by the optical path changing elements126aand126b.In other words, the optical path synthesizing element16B synthesizes the colors of the light beams L2and L3. The optical path synthesizing element16B is configured by a dichroic mirror, for example. It is to be noted that the optical path synthesizing element16B may be configured by a dichroic prism.

Also in the present modification example, similarly to the foregoing first embodiment, a portion (light beam L11) of the light beam L1in the wavelength region W1emitted from the light source unit11A passes through the optical path splitting element16A, whereas the remaining portion (light beam L12) is reflected by the optical path splitting element16A, so that the optical path is split. When the light beam L11having passed through the optical path splitting element16A is focused, by the lens123, on the fluorescent body171ain the wavelength converter17A, the light beam L2in the wavelength region W2is generated due to fluorescent emission. The light beam L2with a converted wavelength passes through the rotating body172, undergoes an optical path change by the optical path changing elements126a,and is then incident on the optical path synthesizing element16B. In contrast, when the light beam L12reflected by the optical path splitting element16A is focused, by the lens124, on the fluorescent body171bof the wavelength converter17B, the light beam L3in the wavelength region W3is generated due to fluorescent emission. This light beam L3with a converted wavelength passes through the rotating body172, undergoes an optical path change by the optical path changing elements126b,and is then incident on the optical path synthesizing element16B. The light beam L2in the wavelength region W2passes through the optical path synthesizing element16B, whereas the light beam L3in the wavelength region W3is reflected by the optical path synthesizing element16B. As a result, the optical paths of the light beams L2and L3are synthesized. In other words, the colors of the light beams L2and L3are synthesized. The synthesized light beam of the light beams L2and L3constitutes an output of the light source device10B.

As in the present modification example, the optical path splitting element16A and the optical path synthesizing element16B may be separate members, and the wavelength converters17A and17B may each employ a transmission type. This configuration also makes it possible to use the light source11(light source unit11A) which emits the light beam L1in a single wavelength region, i.e., the wavelength region W1, to synthesize light beams in a plurality of wavelength regions, i.e., in the wavelength regions W2and W3, and output the synthesized light beam. Consequently, it is possible to achieve effects similar to those of the foregoing first embodiment.

Modification Example 3

FIG. 11illustrates a configuration example of a light source device (light source device10C) according to Modification Example 3. The light source device10C includes a light source unit11A, a wavelength converter17A, a lens123, a light source11B, and an optical path synthesizing element18, for example. The light source11B is a light source that emits the light beam L3in a wavelength region W3, for example, and is configured by an LED or the semiconductor laser, for example. The optical path synthesizing element18synthesizes optical paths of the light beams L2and L3in the respective wavelength regions W2and W3. In other words, the optical path synthesizing element18synthesizes the colors of the light beams L2and L3. The optical path synthesizing element18is configured by a dichroic mirror, for example.

In the present modification example, the light beam L1in the wavelength region W1emitted by the light source unit11A is focused, by the lens123, on the fluorescent body171aof the wavelength converter17A, thus generating the light beam L2in the wavelength region W2. This light beam L2with a converted wavelength passes through the rotating body172, and is incident on the optical path synthesizing element18along a Y axis ofFIG. 11. In contrast, the light beam L3in the wavelength region W3emitted by the light source11B is incident on the optical path synthesizing element18along an X axis ofFIG. 11. The light beam L2in the wavelength region W2is reflected by the optical path synthesizing element18, whereas the light beam L3in the wavelength region W3passes through the optical path synthesizing element18. As a result, the optical paths of the light beams L2and L3are synthesized. In other words, the colors of the light beams L2and L3are synthesized. The synthesized color of the light beams L2and L3constitutes an output of the light source device10C.

As in the present modification example, the configuration may be adopted in which the light-transmission type wavelength converter17A and the light source11B are used.

Next, description is given of some application examples of the light source device in the foregoing embodiments and modification examples. It is to be noted that the light source device10in the foregoing first embodiment is used for the following illustration and description. However, application examples are applicable to each of the light source devices in the foregoing second embodiment and Modification Examples 1 to 3.

Application Example 1

FIG. 12is a functional block diagram illustrating an overall configuration of a projection display unit (projection display unit1) according to Application Example 1. This projection display unit1is a display unit that projects an image onto a screen110(projection surface). The projection display unit1is coupled, via an interface (I/F), to an external image supply unit, such as a computer, e.g., a personal computer (PC), and various image players, all of which are not illustrated. In addition, the projection display unit1performs projection onto the screen110on the basis of an image signal inputted to the interface.

The projection display unit1includes a light source driver31, the light source device10, a light modulating device32, a projection optical system33, an image processor34, a frame memory35, a panel driver36, a projection optical system driver37, and a controller30, for example.

The light source driver31outputs a pulse signal that controls a light emission timing of the light source11disposed in the light source device10. For example, this light source driver31includes a PWM setting unit, a PWM signal generator, and a limiter, all of which are not illustrated. The light source driver31controls a light source driver in the light source device10and PWM-controls the light source11under control of the controller30, thereby turning on and off the light source11or adjusting luminance of the light source11.

In addition to the components described in the foregoing first embodiment, the light source device10includes the light source driver that drives the light source11and a current value setting section that sets a current value when the light source11is driven, for example, both of which are not illustrated. The light source driver may generate a pulse current having a current value set by the current value setting section, on the basis of a power source supplied from an unillustrated power supply circuit and in synchronization with a pulse signal inputted from the light source driver31. The generated pulse current is supplied to the light source11.

The light modulating device32modulates light, i.e., illumination light, outputted from the light source device10on the basis of the image signal, thereby generating image light beams. For example, the light modulating device32includes three transmission or reflective light valves corresponding to respective colors, such as R, G, and B. Examples of these light valves include a liquid crystal panel that modulates blue light (B), a liquid crystal panel that modulates red light (R), and a liquid crystal panel that modulates green light (G). For example, a liquid crystal element, such as liquid crystal on silicon (LCOS), may be used as a reflective liquid crystal panel. However, the light modulating device32is not limited to the liquid crystal element. Alternatively, other optical conversion elements, such as a digital micromirror device (DMD), may be used. The R, G, and B color light beams that have been modulated by the light modulating device32are synthesized by an unillustrated cross dichroic prism, for example, and then the synthesized color light beam is guided to the projection optical system33.

The projection optical system33includes, for example, a lens group that projects the light beams modulated by the light modulating device32onto the screen110, thereby forming an image thereon.

The image processor34acquires the image signal received from the outside to, for example, determine the size and resolution of an image and to identify whether the image is a still image or a moving image. In a case where the image is a moving image, the image processor34also determines attributes, such as a frame rate, of the image data, for example. Further, in a case where the resolution of the image signal acquired is different from the display resolution of each of the liquid crystal panels in the light modulating device32, the image processor34performs a resolution conversion process. The image processor34expands the processed images for each frame in the frame memory35, and outputs the images for each frame expanded in the frame memory35to the panel driver36as display signals.

The panel driver36drives the liquid crystal panels in the light modulating device32. This driving operation of the panel driver36causes optical transmittances of the pixels arranged in each liquid crystal panel to be varied, thereby forming an image.

The projection optical system driver37includes a motor that drives lenses disposed in the projection optical system33. This projection optical system driver37drives, for example, the projection optical system33under control of the controller30, thereby adjusting zooming, focusing, and a diaphragm, for example.

The controller30controls the light source driver31, the image processor34, the panel driver36, and the projection optical system driver37.

By providing the projection display unit1with the above-described light source device10, it is possible to achieve a simple and compact configuration of an entire device.

Application Example 2

FIG. 13schematically illustrates a configuration of a display system according to Application Example 2.FIG. 14illustrates a functional configuration of the display system according to Application Example 2. This display system includes a wristband type terminal (wristband type information processor)2and a smartphone (external unit)3.

For example, the smartphone3is an information processor that operates in cooperation with the wristband type terminal2. The smartphone3has a function of transmitting an image to be projected or displayed to the wristband type terminal2and receiving information indicating a user's operation from the wristband type terminal2. More specifically, the smartphone3transmits an image of a graphical user interface (GUI) to the wristband type terminal2, and receives a signal indicating a user's operation of the GUI. Then, the smartphone3performs a process in accordance with the received user's operation, and transmits an image of the GUI updated with this process to the wristband type terminal2.

It is to be noted that an external unit that operates in cooperation with the wristband type terminal2is not limited to a smartphone; the external unit may be another information processor, examples of which include a digital still camera, a digital video camera, a personal digital assistant (PDA), a personal computer (PC), a notebook personal computer (PC), a tablet terminal, a portable phone terminal, a portable music player, a portable image processor, and a portable gaming machine.

The wristband type terminal2includes, for example a display section210and the projection display unit1provided with a light source device, such as the light source device10, in one of the foregoing embodiments and modification examples. The wristband type terminal2is used while being attached to a user's wrist, for example, by a band section2a.The band section2ais made of leather, metal, fabric, or rubber, for example, similarly to a watch band.

As illustrated inFIG. 14, for example, the wristband type terminal2further includes a controller220, a communication section230, an imaging section240, an operating section250, and a sensor260. The wristband type terminal2is coupled to the smartphone3through wireless communication and operates in cooperation with the smartphone3. For example, the wristband type terminal2may receive an image from the smartphone3placed in a pocket of user's clothes, and may display the image in the display section210or project the image onto a user's palm through the projection display unit1.

The display section210displays an image, such as a still or moving image, under control of the controller220. For example, the display section210includes a liquid crystal display (LCD) or an organic light-emitting diode (OLED). For example, the display section210is integrated with the operating section250, and function as the so-called touch panel.

The communication section230transmits and receives a signal, such as an image signal or a user operation signal, to and from the smartphone3. Examples of the communication scheme include wireless communication, Bluetooth (registered trademark), wireless high definition (WiHD), a wireless local area network (WLAN), wireless fidelity (Wi-Fi (registered trademark)), near field communication (NFC), and infrared communication. Furthermore, communication using 3G/LTE (long term evolution) or a radio wave in a millimeter band may be conducted.

For example, the imaging section240includes: a lens section that includes, for example, an imaging lens, a diaphragm, a zoom lens, and a focus lens; a driver that drives the lens section to perform a focusing or zooming operation; and a solid-state imaging device that generates an imaging signal on the basis of imaging light acquired through the lens section. For example, the solid-state imaging device is configured by a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) image sensor. The imaging section240outputs data on a captured image as a digital signal to the controller220.

The operating section250has a function of receiving an input signal, i.e., the user operation signal, from the user. For example, the operating section250is configured by buttons, a touch sensor, or a trackball. In this case, the operating section250is integrated with the display section210, thereby functioning as a touch panel. This operating section250outputs the inputted user control signal to the controller220.

The sensor260has a function of acquiring information regarding a user's motion or state. For example, the sensor260is provided with a camera that is intended to capture an image of a user's face or eye, or the hand to which the wristband type terminal2is attached. In addition, for example, the sensor260may include a camera with a depth detecting function, a microphone, a GPS, an infrared sensor, a ray sensor, a myoelectric sensor, a nerve sensor, a sphygmus sensor, a body heat sensor, a gyroscope sensor, an acceleration sensor, and a touch sensor. Among these, the myoelectric sensor, the nerve sensor, the sphygmus sensor, and the body heat sensor may be provided in the band section2a.This configuration enables the sensor260to perform a sensing operation near the user's hand, thereby allowing for accurate detection of the motion of the hand. The sensor260senses a user's motion or state and then outputs information indicating the sensing result to the controller220.

The controller220functions as a processor and a controller, and controls an overall operation of the wristband type terminal2in accordance with various programs. The controller220is configured by a central processing unit (CPU) or a microphone processor, for example. This controller220may include a read only memory (ROM) that stores, for example, programs or arithmetic parameters to be used and a random access memory (RAM) that temporarily stores, for example, parameters varying as appropriate.

The controller220includes a recognizer221and a detector222, for example, which allow for gesture input. The recognizer221has a function of recognizing the motion of the user's hand to which the band section2ais attached. Specifically, the recognizer221recognizes the motion of the hand through, for example image and motion recognition using an image (e.g., image of captured user's hand) inputted from the sensor260. The controller220performs various processes, such as a screen transition, on the basis of the recognition result from the recognizer221. The detector222has a function of detecting a user's operation on an image Y1projected by the projection display unit1. For example, the detector222detect a user's operation on the projected image, such as a flick or a touch, of the projected image. The controller220transmits information indicating the user's operation detected by the detector222to the smartphone3. Then, the smartphone3performs a process in accordance with the user's operation. This enables the wristband type terminal2to perform, in the display section210or on the user's hand, a function, such as the image transition, that is similar to a function to be performed in a case where the user performs an operation, such as a flick or a touch, of the touch panel of the smartphone3. For example, when the user flicks the projected image Y1vertically, the wristband type terminal2performs a function of scrolling the projected image Y1.

It is to be noted that, in the example ofFIG. 13, a map image generated in the smartphone3using a global positioning system (GPS) function is displayed in the map image in the display section210, and is projected as the projected image Y1as well. The display section210has a limitation on its physical size, because the wristband type terminal2is intended to achieve portability. In some cases, it is difficult for the user to see an image displayed in the display section210. In such cases, the projection display unit1is used to project the image onto the hand in an enlarged manner, for example, to an inch size similar to that of the smartphone3, thus making it possible to enhances the visibility of the image. Furthermore, it is possible for the user to see an image, on his or her hand, which is received from the smartphone3being still placed in a pocket or a bag, thus leading to improvement of the usability.

In a display system as described above, in a case of adjusting the color balance of illumination light from the light source device10, or in a case of utilizing infrared light in the sensor260, for example, it is possible to suitably use the light source device, such as the light source device10, in the foregoing embodiments and modification examples.

Application Example 3

FIG. 15schematically illustrates a configuration of a display system according to Application Example 3. This display system includes: the projection display unit1provided with the light source device, such as the light source device10, in the foregoing embodiments and modification examples; a laser pointer4; and a PC5that outputs a content to be projected to the projection display unit1. Examples of the content to be projected includes a diagram, a text, any other various graphic image, a map, and a website.

The laser pointer4has a function of emitting an invisible or visible laser light beam in accordance with a user's pressing operation of an operation button20a.The user may use the laser pointer4to irradiate an image projected onto a screen110with the laser light beam. This enables the user to, for example, make a presentation while pointing out a referenced area with an irradiated point P.

The PC5generates image data to be projected. Further, the PC5transmits this image data to the projection display unit1in a wired or wireless manner, and controls the projection. InFIG. 15, a notebook PC is depicted as an example of the PC5; however, the PC5is not limited to the notebook PC. The PC5may be a desktop PC or a server on a network (cloud).

In this application example, the projection display unit1has an imaging section that projects an image received from the PC5onto the screen110, and recognizes the irradiation of the projected image with the laser pointer4. The imaging section enables detection using the invisible or visible laser light beam with which the screen110is irradiated. This imaging section may be mounted either inside or outside the projection display unit1. By using the light source device, such as the light source device10, in the foregoing embodiments and modification examples in the projection display unit1, it is possible to output synthesized light beams in a plurality of wavelengths by using a single light source, as described above. This makes it possible to achieve a simple and compact configuration of an entire device without having to separately provide light sources used for projection and imaging.

Description has been given heretofore using some embodiments and modification examples. However, the disclosure is not limited to these embodiments and modification examples, and may be modified in a variety of ways. For example, the arrangement and the number of optical components (including one or more light source units, optical path splitting elements, lenses, optical path synthesizing elements, and optical path changing elements) exemplified in the embodiments and modification example are mere examples. Therefore, all of the components do not necessarily have to be provided, or another component may be further provided.

In the examples of the foregoing embodiments and modification examples, one or two types of fluorescent bodies convert a first wavelength region emitted from a light source (excitation light source). However, three or more types of the fluorescent bodies may also be used. Further, the number of light sources is not limited to one; two or more light sources may be disposed depending on applications, provided that it is possible to achieve a configuration in which the optical path of a light beam emitted from a single light source is split, then the light beams are guided to two or more types of fluorescent bodies, and the optical paths or colors of converted wavelengths are synthesized.

Furthermore, the projection display unit and the display system that have been described as application examples of the light source device in the foregoing embodiments and modification examples may be examples, and application examples are not limited to those described above. For example, the light source device of the disclosure is also applicable to a night vision device (night vision system) that use infrared light. It is to be noted that the effects described herein are mere examples and not limitative, and may further include other effects.

The disclosure may have the following configurations.

A light source device including:a light source that emits a light beam in a first wavelength region;an optical path splitting element that splits an optical path of the light beam in the first wavelength region emitted from the light source into a first optical path and a second optical path;a first fluorescent body that is disposed on the first optical path, and emits a light beam in a second wavelength region by undergoing excitation by the light beam in the first wavelength region, the second wavelength region differing from the first wavelength region;a second fluorescent body that is disposed on the second optical path, and emits a light beam in a third wavelength region by undergoing excitation by the light beam in the first wavelength region, the third wavelength region differing from the first and second wavelength regions; andan optical path synthesizing element that synthesizes the light beam in the second wavelength region emitted from the first fluorescent body and the light beam in the third wavelength region emitted from the second fluorescent body.
(2)

The light source device according to (1), in which the optical path splitting element serves also as the optical path synthesizing element.

The light source device according to (1) or (2), in which the optical path splitting element transmits, along the first optical path, a portion of the light beam in the first wavelength region emitted from the light source, and reflects, along the second optical path, another portion of the light beam in the first wavelength region emitted from the light source.

The light source device according to (2), in which the optical path splitting element transmits one of the light beam in the second wavelength region and the light beam in the third wavelength region, and reflects the other of the light beam in the second wavelength region and the light beam in the third wavelength region.

The light source device according to any one of (1) to (4), further including:a first wavelength converter; anda second wavelength converter,the first wavelength converter including the first fluorescent body, a rotating body that holds the first fluorescent body, and a driver that drives the rotating body,the second wavelength converter including the second fluorescent body, a rotating body that holds the second fluorescent body, and a driver that drives the rotating body.
(6)

The light source device according to any one of (1) to (4), further including a third wavelength converter, the third wavelength converter including the first fluorescent body, the second fluorescent body, a rotating body that holds the first fluorescent body and the second fluorescent body, and a driver that drives the rotating body.

The light source device according to any one of (1) to (6), in which the optical path splitting element includes one of a dichroic mirror and a dichroic prism.

The light source device according to (5), in which each of the first wavelength converter and the second wavelength converter employs a reflective type.

The light source device according to (1) or (2), in whichthe light source includes a light source that emits a linearly polarized light beam as the light beam in the first wavelength region, andthe optical path splitting element transmits a first polarization component of the light beam in the first wavelength region along the first optical path, and reflects a second polarization component of the light beam in the first wavelength region along the second optical path.
(10)

The light source device according to (9), further including a polarization rotating element between the light source and the optical path splitting element.

The light source device according to (9) or (10), in which the optical path splitting element transmits one of the light beam in the second wavelength region and the light beam in the third wavelength region, and reflects the other of the light beam in the second wavelength region and the light beam in the third wavelength region.

The light source device according to any one of (9) to (11), in which the optical path splitting element includes a polarization beam splitter.

The light source device according to any one of (1) to (12), in whichthe first wavelength region is a blue light region,the second wavelength region covers a green light region and a red light region, andthe third wavelength region is an infrared region.
(14)

The light source device according to any one of (1) to (12), in whichthe first wavelength region is an ultraviolet region,the second wavelength region covers a green light region and a red light region, andthe third wavelength region is an infrared region.
(15)

The light source device according to any one of (1) to (12), in whichthe first wavelength region is a blue light region,the second wavelength region is a green light region, andthe third wavelength region is a red light region.
(16)

The light source device according to any one of (1) to (12), in whichthe first wavelength region is an ultraviolet region,the second wavelength region covers a green light region, andthe third wavelength region is a red light region.
(17)

The light source device according to any one of (1) to (12), in whichthe first wavelength region is an ultraviolet region,the second wavelength region covers a green light region and a red light region, andthe third wavelength region is a blue light region.
(18)

The light source device according to any one of (1) to (12), in whichthe first wavelength region is a blue light region,the second wavelength region covers a green light region and a red light region, andthe third wavelength region is a red light region.
(19)

A projection display unit provided with a light source device, the light source device including:a light source that emits a light beam in a first wavelength region;an optical path splitting element that splits an optical path of the light beam in the first wavelength region emitted from the light source into a first optical path and a second optical path;a first fluorescent body that is disposed on the first optical path, and emits a light beam in a second wavelength region by undergoing excitation by the light beam in the first wavelength region, the second wavelength region differing from the first wavelength region;a second fluorescent body that is disposed on the second optical path, and emits a light beam in a third wavelength region by undergoing excitation by the light beam in the first wavelength region, the third wavelength region differing from the first and second wavelength regions; andan optical path synthesizing element that synthesizes the light beam in the second wavelength region emitted from the first fluorescent body and the light beam in the third wavelength region emitted from the second fluorescent body.
(20)

A display system having a projection display unit, the projection display unit provided with a light source device, the light source device including:a light source that emits a light beam in a first wavelength region;an optical path splitting element that splits an optical path of the light beam in the first wavelength region emitted from the light source into a first optical path and a second optical path;a first fluorescent body that is disposed on the first optical path, and emits a light beam in a second wavelength region by undergoing excitation by the light beam in the first wavelength region, the second wavelength region differing from the first wavelength region;a second fluorescent body that is disposed on the second optical path, and emits a light beam in a third wavelength region by undergoing excitation by the light beam in the first wavelength region, the third wavelength region differing from the first and second wavelength regions; andan optical path synthesizing element that synthesizes the light beam in the second wavelength region emitted from the first fluorescent body and the light beam in the third wavelength region emitted from the second fluorescent body.

This application is based upon and claims the benefit of priority of the Japanese Patent Application No. 2015-085782 filed with the Japan Patent Office on Apr. 20, 2015, the entire contents of which are incorporated herein by reference.

It should be understood that those skilled in the art can contemplate various modifications, combinations, sub-combinations, and variations on the basis of design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.