JP6353583B2 - Light source device and image projection device - Google Patents

Description

  The present invention relates to a light source device and an image projecting device, and more particularly to a light source device used as a light source of a projection type image display device (image projecting device) such as a projector and an image projecting device including the same.

  In recent years, opportunities for using a projection type image display device such as a projector have increased in appreciation of movies at home and presentations at conferences. In such a projector, a discharge lamp such as a high-intensity mercury lamp is generally used as a light source. A projector using a solid-state light-emitting element has also been proposed with the progress of development technology of recent solid-state light-emitting elements (for example, semiconductor lasers, light-emitting diodes) (see, for example, Patent Document 1).

  The projector proposed in Patent Document 1 is a DLP (Digital Light Processing: registered trademark) type projector. This type of projector displays images in full color by displaying light of different colors in a time-sharing manner several thousand times per second. Therefore, in the projector of Patent Document 1, a red light emitting device, a green light emitting device, and a blue light emitting device each using a solid light emitting element are prepared separately, and the light emitted from each light emitting device is time-division controlled and emitted to the outside. To display image light.

  Each light-emitting device used in the projector of Patent Document 1 includes a light-emitting wheel that is driven to rotate, a light-emitting body that is formed on the surface of the light-emitting wheel, absorbs excitation light, and emits light of a predetermined color, and excitation light. And an excitation light source (solid light-emitting element) that emits light. Further, as the excitation light source used for each light emitting device, a light source that emits excitation light in a wavelength band shorter than the wavelength band of light emitted from the light emitter is used.

JP 2010-86815 A

  As described above, a projector that does not use a mercury lamp has been conventionally proposed. With such a projector, a mercury-free projector can be realized, and it is possible to cope with recent environmental problems. Further, when a solid-state light emitting element such as a semiconductor laser or a light emitting diode is used as a light source, there are advantages that it has a longer life than a mercury lamp and a decrease in luminance is small.

  However, the technique proposed in Patent Document 1 is applied only to a light source device (illumination device) that emits a plurality of monochromatic lights having different wavelengths in a time-division manner, such as a DLP (registered trademark) projector. Is possible. For example, the technique proposed in Patent Document 1 may be applied to an application that requires a light source device that emits white light, such as an image display device such as a 3LCD (Liquid Crystal Display) projector. Can not.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a mercury-less light source device that can be applied to various uses such as a 3LCD projector, and an image projection device including the mercury-free light source device. Is to provide.

In order to solve the above problems, a light source device of the present invention includes an excitation light source that emits excitation light including first color light, and at least part of the excitation light as first color light when the excitation light is incident. Is a fluorescent member having a phosphor that converts to a different second color light, a fluorescent member that is provided on the opposite side of the phosphor from the incident side of the excitation light, and light between the excitation light source and the fluorescent member. A first color light that is provided on the road, converts the second polarization component of the first polarization component and the second polarization component in the first color light into the first polarization component, and is converted into the first polarization component and the reflection member. A quarter-wave plate for emitting the reflected second color light . In this specification, “wavelength” means not only a single wavelength but also a predetermined wavelength band.

  Moreover, the image projector of this invention is set as the structure provided with a light source device part and an image projector, and the function of each part is as follows. The light source device section has the same configuration as the light source device of the present invention. The image projection unit generates predetermined image light using the light emitted from the light source device unit, and projects the generated image light to the outside.

  In the present invention, the light source device (light source device unit) includes light having the second wavelength band emitted from the phosphor (second color light) and the first wavelength band reflected by the phosphor and the first reflecting film. Combined light including part of the excitation light having (first color light) is emitted. That is, in the present invention, light having a wavelength band different from that of the excitation light and the emission light (second color light) including the first color light is emitted. Therefore, in the present invention, for example, when the excitation light is blue light and the emitted light is light including both components of red light and green light (for example, yellow light), white light is emitted from the light source device (light source device). Part).

  As described above, the light source device (light source device unit) of the present invention can emit light having a wavelength band different from that of the excitation light including the first color light and the emission light (second color light). By appropriately setting the combination of the first wavelength band and the second wavelength band of the emitted light, for example, light such as white light can be emitted. Therefore, according to the present invention, it is possible to provide a mercury-free light source device that can be applied to various uses such as a 3LCD projector, and an image projection device including the mercury-free light source device.

1 is a schematic block configuration diagram of an image display device according to an embodiment of the present invention. It is a schematic block diagram of the fluorescent member used for the light source device part (illuminating device) which concerns on one Embodiment of this invention. It is a figure which shows the example of 1 structure of the reflecting film used with a fluorescent member. It is a figure which shows the example of a spectral characteristic of the polarizing beam splitter used with the light source device part which concerns on one Embodiment of this invention. It is a figure for demonstrating operation | movement of a polarizing beam splitter. It is the spectrum characteristic of the emitted light of the light source device part (illuminating device) which concerns on one Embodiment of this invention. It is a figure which shows the structural example of the spectroscopy optical system of the modification 1.

Hereinafter, an example of an illumination device (light source device) according to an embodiment of the present invention and an image display device including the illumination device will be described in the following order with reference to the drawings. In the present embodiment, a 3LCD projector (image projection apparatus) is described as an example of the image display apparatus. However, the present invention is not limited to this, and any image display apparatus that requires white light can be used. It can be applied and the same effect can be obtained.
1. 1. Configuration example of image display device 2. Configuration example of light source device section (illumination device) 3. Configuration example of fluorescent member 4. Configuration example of polarization beam splitter 5. Example of operation of light source unit Various modifications

[1. Configuration example of image display apparatus]
FIG. 1 shows a schematic configuration of an image display apparatus according to an embodiment of the present invention. In FIG. 1, for the sake of simplification of description, only main parts that operate when image light is projected to the outside in the image display apparatus 10 of the present embodiment are mainly shown. FIG. 1 shows a configuration example of a 3LCD type projector using a transmissive LCD light modulation element, but the present invention is not limited to this. The present invention can also be applied to a 3LCD projector using a reflective LCD light modulation element.

  The image display device 10 includes a light source device unit 1 (illumination device) and an optical engine unit 2 (image projection unit). The configuration of the light source device unit 1 will be described in detail later.

  The optical engine unit 2 optically processes light emitted from the light source device unit 1 (in this example, white light LW) to generate image light LI, and enlarges and projects the image light LI onto an external screen, for example, To do. The optical engine unit 2 includes, for example, a spectroscopic optical system 20, three LCD light modulation elements (hereinafter referred to as a first LCD panel 21 to a third LCD panel 23, respectively), a prism 24, and a projection optical system 25. In addition, the structure of the optical engine part 2 is not limited to the example shown in FIG. 1, For example, it can change suitably according to a use etc. For example, various optical elements necessary for the optical path between the components in the optical engine unit 2 may be appropriately arranged.

  Moreover, in the optical engine part 2 of this example, both are arrange | positioned so that the light-projection surface of the 1st LCD panel 21 and the light-projection surface of the 3rd LCD panel 23 may oppose, and it is in the direction orthogonal to the opposing direction of both. A second LCD panel 22 is arranged. Then, the prism 24 is disposed in a region surrounded by the light emission surfaces of the first LCD panel 21 to the third LCD panel 23. In this example, the projection optical system 25 is disposed at a position facing the light emitting surface of the second LCD panel 22 with the prism 24 interposed therebetween. The spectroscopic optical system 20 is provided on the light incident side of the first LCD panel 21 to the third LCD panel 23.

  The spectroscopic optical system 20 includes, for example, a dichroic mirror, a reflection mirror, and the like, and splits the white light LW incident from the light source device unit 1 into the blue light LB, the green light LG, and the red light LR, and the light of each wavelength component. To the corresponding LCD panel. In this example, the spectroscopic optical system 20 emits the split blue light LB, green light LG, and red light LR to the first LCD panel 21, the second LCD panel 22, and the third LCD panel 23, respectively. In the present embodiment, in the spectroscopic optical system 20, the polarization direction of each wavelength component is adjusted to be a predetermined direction.

  Each of the first LCD panel 21 to the third LCD panel 23 is composed of a transmissive LCD panel. Each LCD panel changes the arrangement of liquid crystal molecules sealed in a liquid crystal cell (not shown) based on a drive signal from a panel drive unit (not shown), thereby transmitting or blocking incident light in units of liquid crystal cells ( Modulate). Each LCD panel emits modulated light having a predetermined wavelength (modulated light) to the prism 24.

  The prism 24 combines the modulated light of each wavelength component incident from the first LCD panel 21 to the third LCD panel 23 and emits the combined light, that is, the image light LI to the projection optical system 25.

  The projection optical system 25 enlarges and projects the image light incident from the prism 24 onto a display surface such as an external screen.

[2. Configuration example of light source device unit 1]
Next, the internal configuration of the light source device unit 1 of the present embodiment will be described with reference to FIG. The light source unit 1 includes an excitation light source 11, a polarizing beam splitter 12 (spectral optical system), a quarter wavelength plate 13, a condensing optical system 14 (optical system), a fluorescent member 15, and a motor 16 (driving). Part).

  In the light source device unit 1 of the present embodiment, from the fluorescent member 15 side, a reflective film 31 and a phosphor layer 32, a condensing optical system 14, a quarter wavelength plate 13, and a polarizing beam splitter 12 described later of the fluorescent member 15 are described. Are arranged on the optical path of the emitted light from the fluorescent member 15 in this order. The excitation light source 11 is disposed in a direction orthogonal to the optical path of the emitted light from the fluorescent member 15 and at a position facing one light incident surface of the polarization beam splitter 12.

  The excitation light source 11 is composed of a solid light emitting element that emits light of a predetermined wavelength (first wavelength). In this example, a blue laser that emits blue light having a wavelength of 445 nm (excitation light Bs) is used as the excitation light source 11. The excitation light source 11 emits linearly polarized light (S-polarized) excitation light Bs. In the present embodiment, the wavelength of the excitation light is made shorter than the wavelength of light (hereinafter referred to as emitted light) emitted from a phosphor layer 32 described later in the fluorescent member 15.

  When the excitation light source 11 is configured with a blue laser, the excitation light Bs with a predetermined output may be obtained with a single blue laser. However, the excitation light Bs with a predetermined output may be combined by combining light emitted from a plurality of blue lasers. You may make it the structure which obtains light Bs. Furthermore, the wavelength of blue light (excitation light Bs) is not limited to 445 nm, and any wavelength can be used as long as it is within the wavelength band of light called blue light.

  The polarization beam splitter 12 (PBS) separates the excitation light Bs incident from the excitation light source 11 and the outgoing light (combined light) incident from the fluorescent member 15. Specifically, the polarization beam splitter 12 reflects the excitation light Bs incident from the excitation light source 11 and emits the reflected light to the fluorescent member 15 via the condensing optical system 14. The polarizing beam splitter 12 transmits the light emitted from the fluorescent member 15 and emits the transmitted light to the spectroscopic optical system 20 in the optical engine unit 2.

  In the present embodiment, the spectral characteristics of the polarization beam splitter 12 are designed so that the polarization beam splitter 12 realizes the above-described light separation operation. A specific example of the spectral characteristics of the polarization beam splitter 12 will be described in detail later. Further, the configuration of the optical system that separates the excitation light Bs incident from the excitation light source 11 and the light emitted from the fluorescent member 15 is not limited to the polarization beam splitter 12, and enables the above-described light separation operation. Any optical system can be used as long as it is configured.

  The quarter-wave plate 13 is a phase element that generates a phase difference of π / 2 with respect to incident light. When the incident light is linearly polarized light, the linearly polarized light is converted into circularly polarized light, and the incident light is circularly polarized light. In this case, circularly polarized light is converted to linearly polarized light. In the present embodiment, the quarter wavelength plate 13 converts the linearly polarized excitation light emitted from the polarization beam splitter 12 into circularly polarized excitation light, and circularly polarized light included in the combined light emitted from the fluorescent member 15. Is converted into linearly polarized light.

  The condensing optical system 14 condenses the excitation light emitted from the quarter wavelength plate 13 to a predetermined spot diameter, and emits the condensed excitation light (hereinafter referred to as “condensed light”) to the fluorescent member 15. . The condensing optical system 14 converts the combined light emitted from the fluorescent member 15 into parallel light, and emits the parallel light to the quarter-wave plate 13. In addition, the condensing optical system 14 may be configured by, for example, a single collimator lens, or may be configured to convert incident light into parallel light using a plurality of lenses.

  The fluorescent member 15 absorbs a part of the excitation light (blue light) incident through the condensing optical system 14, emits light in a predetermined wavelength band (second wavelength), and transmits the remaining excitation light. reflect. Then, the fluorescent member 15 combines the emitted light and a part of the reflected excitation light, and emits the combined light to the condensing optical system 14.

  In this example, since the light incident on the optical engine unit 2 is white light LW, the fluorescent member 15 emits light in a wavelength band (about 480 to 680 nm) including green light and red light by the excitation light. In this embodiment, emitted light in a wavelength band including green light and red light and a part of excitation light (blue light) reflected by the fluorescent member 15 (a reflective film 31 and a phosphor layer 32 described later) are used. Combine to produce white light. A more detailed configuration of the fluorescent member 15 will be described in detail later.

  Further, since the emitted light emitted from the fluorescent member 15 is light that spreads in a Lambertian (uniform diffusion) shape, if the distance between the condensing optical system 14 and the fluorescent member 15 is long, the condensing optical system 14 The emitted light cannot be sufficiently collected, and the utilization efficiency of the excitation light is reduced. If the spot diameter of the excitation light applied to the fluorescent member 15 is too large, the spread of the emitted light also increases. In this case as well, the utilization efficiency of the excitation light decreases. Therefore, in the present embodiment, the condensing optical system 14 has a configuration such as a lens configuration, a focal length, and an arrangement position, and the condensing optical system 14 and the fluorescent member 15 so that sufficient excitation light utilization efficiency can be obtained. And the distance is set.

  The motor 16 rotationally drives the fluorescent member 15 at a predetermined rotational speed. At this time, the motor 16 drives the fluorescent member 15 so that the fluorescent member 15 rotates in a plane orthogonal to the excitation light irradiation direction (an excitation light irradiation surface of the phosphor layer 32 described later). As a result, the irradiation position of the excitation light in the fluorescent member 15 changes (moves) in time at a speed corresponding to the rotational speed in a plane orthogonal to the irradiation direction of the excitation light.

  As described above, the fluorescent member 15 is rotationally driven by the motor 16 and the irradiation position of the excitation light in the fluorescent member 15 is changed with time, so that the temperature rise at the irradiation position can be suppressed. A decrease in luminous efficiency can be prevented. In addition, it takes some time (for example, several nsec) until the phosphor atoms absorb the excitation light and emit light, and even if the next excitation light is irradiated to the phosphor atoms during the excitation period, It does not emit light. However, by changing the irradiation position of the excitation light in the fluorescent member 15 with time as in the present embodiment, phosphor atoms that are not excited are successively arranged at the irradiation position of the excitation light. The phosphor layer 32 can emit light more efficiently.

  In the present embodiment, an example in which the fluorescent member 15 is rotationally driven by the motor 16 is shown. However, the present invention is not limited to this, and the irradiation position of the excitation light in the fluorescent member 15 may be changed with time. Any configuration can be used. For example, the irradiation position of the excitation light may be changed with time by linearly reciprocating the fluorescent member 15 in a predetermined direction in a plane orthogonal to the irradiation direction of the excitation light. Further, the irradiation position of the excitation light may be changed with time by fixing the fluorescent member 15 and moving the excitation light source 11 and various optical systems relative to the fluorescent member 15.

[3. Configuration example of fluorescent member]
Next, a more detailed configuration of the fluorescent member 15 will be described with reference to FIGS. 2A is a front view of the fluorescent member 15 viewed from the light collecting optical system 14 side, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. 2 (c) is a front view of the fluorescent member 15 viewed from the side opposite to the condensing optical system 14. FIG.

  The fluorescent member 15 includes a disk-shaped substrate 30, a reflective film 31 (first reflective film) and a phosphor layer 32 (phosphor) formed on the surface of one side (excitation light incident side) of the substrate 30. Have

  The substrate 30 is made of a transparent material such as glass or transparent resin. The material for forming the substrate 30 is not limited to a transparent material, and any material can be used as long as it has a predetermined strength. The size such as the thickness of the substrate 30 is appropriately set in consideration of, for example, required strength and weight. The center of the substrate 30 is attached to the rotating shaft 16a of the motor 16, and the substrate 30 is fixed to the rotating shaft 16a by a fixing hub 16b.

  The reflective film 31 is formed in a donut shape on one surface of the substrate 30 as shown in FIG. The reflective film 31 is arranged on the substrate 30 so that the donut-shaped reflective film 31 and the substrate 30 are concentric. The radial width of the reflective film 31 is set to be larger than the spot size of the excitation light (condensed light) collected by the condensing optical system 14.

  The reflective film 31 reflects all light regardless of the wavelength and incident angle of incident light. Therefore, the reflection film 31 not only reflects the light (emitted light) excited by the phosphor layer 32 to the condensing optical system 14 side but also one of the excitation light (blue light) transmitted through the phosphor layer 32. The part is also reflected to the condensing optical system 14 side.

Here, FIG. 3 shows a configuration example of the reflective film 31. The reflective film 31 includes a first dielectric layer 31 a made of, for example, a SiO ₂ layer or a MgF ₂ layer, and a second dielectric layer 31 b made of, for example, a TiO ₂ layer or a Ta ₂ O ₃ layer on the substrate 30. Are alternately stacked. That is, the reflective film 31 can be formed of a dichroic mirror (dichroic film). When the reflective film 31 is configured by a dichroic mirror as shown in FIG. 3, for example, by adjusting the number of dielectric layers stacked, the thickness of each dielectric layer, the formation material of each dielectric layer, etc. The reflection (transmission) characteristic of the reflection film 31 can be set to a predetermined characteristic. In addition, the number of laminated layers of the first dielectric layer 31a and the second dielectric layer 31b is usually several to several tens. Further, the first dielectric layer 31a and the second dielectric layer 31b are formed using a lamination method such as a vapor deposition method or a sputtering method. Note that the configuration of the reflective film 31 is not limited to the example shown in FIG. 3, and may be configured of a metal film such as aluminum.

  The phosphor layer 32 is formed of a layered phosphor, and absorbs a part of the excitation light and emits light in a predetermined wavelength band when the excitation light is incident. Further, the phosphor layer 32 transmits part of the remaining excitation light that is not absorbed and diffuses (reflects) the remaining excitation light. The excitation light component reflected by the phosphor layer 32 becomes non-polarized light.

  In the present embodiment, part of the excitation light reflected by the reflective film 31 and the phosphor layer 32 and the emitted light from the phosphor layer 32 are combined to generate white light. For example, it is made of YAG (Yttrium Aluminum Garnet) fluorescent material. In this case, when blue excitation light is incident, the phosphor layer 32 emits light (yellow light) in a wavelength band of 480 to 680 nm.

  As the phosphor layer 32, any film having any structure and material can be used as long as it emits light in a wavelength band including red light and green light. However, from the viewpoint of light emission efficiency and heat resistance. It is preferable to use a film formed of a YAG phosphor material.

  The phosphor layer 32 is formed by applying a predetermined fluorescent agent mixed with a fluorescent material and a binder on the reflective film 31. In the example shown in FIGS. 2A to 2C, since the phosphor layer 32 is formed over the entire surface of the reflective film 31, the surface shape of the phosphor layer 32 is also a donut shape. In addition, since the fluorescent substance layer 32 should just be formed in the area | region where excitation light is irradiated, the shape of the fluorescent substance layer 32 is not limited to the example shown to Fig.2 (a)-(c), For example, The width of the phosphor layer 32 in the radial direction may be narrower than that of the reflective film 31.

  In addition, the light emission amount and the ratio of the amount of transmitted and reflected light and the amount of reflection (diffusion amount) in the phosphor layer 32 can be adjusted by, for example, the thickness of the phosphor layer 32 and the phosphor density (content). it can. Therefore, in the present embodiment, the thickness of the phosphor layer 32, the phosphor density, and the like are adjusted so that the emitted light from the light source device unit 1 becomes white light.

  In addition, although the fluorescent member 15 of the said embodiment demonstrated the example which provides a layered fluorescent substance (phosphor layer 32) on the board | substrate 30 via the reflecting film 31, this invention is not limited to this. For example, when the phosphor is composed of a plate member having sufficient rigidity, the substrate 30 may not be provided. In this case, the reflection film 31 may be formed directly on one surface of the phosphor made of a plate-like member, or a reflection mirror is prepared separately from the phosphor, and the reflection mirror is used instead of the reflection film 31. You may use for.

[4. Configuration example of polarization beam splitter]
In the light source device unit 1 of the present embodiment, as shown in FIG. 1, the optical path of the excitation light incident on the fluorescent member 15 from the excitation light source 11 via the polarization beam splitter 12, and the fluorescent member 15 to the optical engine unit 2. The optical path of the incident combined light overlaps. Therefore, in this embodiment, as described above, the spectral characteristics of the polarization beam splitter 12 are adjusted as appropriate to separate both lights.

  FIG. 4 shows an example of spectral characteristics of the polarizing beam splitter 12 used in this embodiment. The horizontal axis of the spectral characteristics shown in FIG. 4 is the wavelength, and the vertical axis is the transmittance. Also, a characteristic Tp indicated by a solid line in FIG. 4 is a transmittance characteristic of the polarizing beam splitter 12 with respect to incident light of P-polarized light, and a characteristic Rp indicated by a broken line is the reflectance of the polarizing beam splitter 12 with respect to incident light of P-polarized light. It is a characteristic. Further, a characteristic Ts indicated by a dotted line in FIG. 4 is a transmittance characteristic of the polarization beam splitter 12 with respect to S-polarized incident light, and a characteristic Rs indicated by a one-dot chain line is a reflection of the polarization beam splitter 12 with respect to S-polarized incident light. It is a rate characteristic.

  In the polarizing beam splitter 12 used in the present embodiment, as shown in FIG. 4, the transmittance of the light component in the wavelength band of 480 to 680 nm emitted from the phosphor layer 32 is approximately regardless of the polarization direction. 100% and the reflectance is about 0%. That is, all the light in the wavelength band of 480 to 680 nm (yellow light) is transmitted through the polarization beam splitter 12.

  On the other hand, the transmittance of the polarization beam splitter 12 with respect to the P-polarized blue light is about 100% and the reflectance is about 0%, as shown in FIG. Further, the transmittance of the polarizing beam splitter 12 with respect to S-polarized blue light is about 0%, and the reflectance is about 100%. That is, the polarization beam splitter 12 transmits the light when P-polarized blue light is incident, and reflects the light when S-polarized blue light is incident.

  By setting the spectral characteristics of the polarizing beam splitter 12 to the characteristics shown in FIG. 4, the excitation light incident on the fluorescent member 15 and the outgoing light from the fluorescent member 15 can be separated. Specifically, since the excitation light Bs (blue light) incident from the excitation light source 11 is S-polarized light, it is reflected by the polarization beam splitter 12 and guided to the fluorescent member 15.

  On the other hand, the emitted light component included in the combined light emitted from the fluorescent member 15 is a light component in the wavelength band of 480 to 680 nm, and thus passes through the polarization beam splitter 12. In addition, among the excitation light (blue light) components included in the combined light emitted from the fluorescent member 15, the excitation light component reflected from the reflective film 31 is P-polarized light as will be described later. 12 is transmitted. Further, among the excitation light components included in the combined light emitted from the fluorescent member 15, the excitation light component directly reflected from the phosphor layer 32 is non-polarized, so about half of the excitation light component is a polarized beam. It passes through the splitter 12. That is, a part of the combined light emitted from the fluorescent member 15 is transmitted through the polarization beam splitter 12, and the transmitted combined light is guided to the spectral optical system 20 in the optical engine unit 2 as white light LW.

[5. Example of operation of light source unit]
Next, an example of the operation of the light source device unit of the present embodiment will be specifically described with reference to FIGS. FIG. 5 is a diagram showing the state of spectral operation of the polarizing beam splitter 12 of the present embodiment, in which the circle A1 in FIG. 5 indicates the polarization direction of S-polarized light, and the white arrow A2 is polarization of P-polarized light. Indicates direction. In FIG. 5, the illustration of the non-polarized excitation light component directly reflected from the phosphor layer 32 is omitted to simplify the description.

  First, the excitation light source 11 emits S-polarized excitation light Bs (blue light) to the polarization beam splitter 12. Next, the polarization beam splitter 12 reflects the incident excitation light Bs in a direction toward the fluorescent member 15. Next, the polarization beam splitter 12 emits the reflected excitation light to the condensing optical system 14 via the quarter wavelength plate 13. The condensing optical system 14 condenses the incident excitation light to a predetermined spot diameter and irradiates the fluorescent member 15 with the condensed light.

  Next, when the phosphor layer 32 of the phosphor member 15 is irradiated with excitation light, the phosphor layer 32 absorbs part of the excitation light, and thereby has a wavelength of 480 to 680 nm including red light and green light. It emits light in the band (yellow light). At this time, the phosphor layer 32 diffuses a part of the excitation light that is not absorbed by the phosphor layer 32 and reflects it to the condensing optical system 14 side, and transmits the remaining part of the excitation light that is not absorbed. To the reflective film 31. The reflection film 31 reflects the excitation light transmitted through the phosphor layer 32 toward the condensing optical system 14. At this time, part of the light emitted from the phosphor layer 32 is also reflected by the reflective film 31 toward the condensing optical system 14.

  As a result, the emitted light from the phosphor layer 32 and a part of the excitation light reflected from the phosphor layer 32 and the reflection film 31 are combined in the fluorescent member 15, and the combined light is emitted from the fluorescent member 15. The light is emitted to the condensing optical system 14.

  Next, the condensing optical system 14 converts the combined light emitted from the fluorescent member 15 into parallel light, and emits the parallel light to the polarization beam splitter 12 via the quarter wavelength plate 13.

  At this time, the emitted light component included in the combined light passing through the quarter-wave plate 13, that is, the red light component Rps (broken arrow in FIG. 5) and the green light component Gps (dashed line arrow) are not polarized (P Including both polarization component and S polarization component). Therefore, the red light component Rps and the green light component Gps included in the combined light pass through the quarter-wave plate 13 as they are and enter the polarization beam splitter 12.

  On the other hand, among the excitation light components (blue light components) included in the combined light, the excitation light component reflected from the reflective film 31 is not applied to the quarter wavelength plate 13 until it enters the polarization beam splitter 12. Pass twice. Specifically, the excitation light component reflected from the reflective film 31 is once each in the optical path of excitation light from the excitation light source 11 to the fluorescent member 15 and in the optical path of combined light from the fluorescent member 15 to the polarization beam splitter 12. Pass through the quarter-wave plate 13 one by one. Therefore, the polarization direction of the reflected light component from the reflective film 31 included in the combined light after passing through the quarter-wave plate 13 is rotated by 90 degrees with respect to the excitation light Bs emitted from the excitation light source 11.

  In this embodiment, since the excitation light Bs emitted from the excitation light source 11 is S-polarized light, the excitation light component Bp (blue light) reflected from the reflective film 31 incident on the polarization beam splitter 12 is As shown in FIG. 5, it becomes P-polarized light. On the other hand, since the excitation light component (not shown in FIG. 5) directly reflected from the phosphor layer 32 is non-polarized light, it passes through the quarter-wave plate 13 as it is and enters the polarization beam splitter 12 (FIG. 5). 5 (not shown).

  In this embodiment, since the polarization beam splitter 12 has the spectral characteristics as shown in FIG. 4, the polarization beam splitter 12 passes the red light component Rps and the green light component Gps included in the combined light as they are. Let

  Of the excitation light components incident on the polarizing beam splitter 12, the reflected light component (Bp) from the reflecting film 31 is P-polarized light, so that the polarizing beam splitter 12 reflects the reflected light component from the reflecting film 31. Pass (Bp) as it is. However, since the reflected light component from the phosphor layer 32 among the excitation light components incident on the polarizing beam splitter 12 is non-polarized light, the polarizing beam splitter 12 has the P-polarized light among the reflected light components. Pass only light components. At this time, the proportion of the excitation light component reflected from the phosphor layer 32 that passes through the polarization beam splitter 12 is about 50%. Therefore, in this embodiment, about 70 to 80% of the excitation light component emitted from the fluorescent member 15 passes through the polarization beam splitter 12.

  As a result, the red light component Rps and the green light component Gps, and the excitation light component (blue light component) reflected by the reflective film 31 and the phosphor layer 32 from the exit surface of the polarization beam splitter 12 on the optical engine unit 2 side. , Ie, white light LW is emitted. In the present embodiment, the white light LW is emitted from the light source device unit 1 in this way.

In the light source device unit 1 of the present embodiment configured as described above, the inventor set the parameters of each part of the light source device unit 1 as follows, and examined the spectral characteristics of the light emitted from the light source device unit 1.
Wavelength of excitation light source 11 (blue laser): 445 nm
Condensing diameter of excitation light: 1mm
Incident angle θ of excitation light: 20 degrees or less Spectral characteristics of polarizing beam splitter 12: characteristics shown in FIG. 4 Distance between condensing optical system 14 and phosphor layer 32: 1 mm or less Rotation speed of fluorescent member 15: 3000 rpm
Forming material of phosphor layer 32: YAG-based phosphor Thickness of phosphor layer 32: 50 μm
Width of phosphor layer 32: 5 mm

  FIG. 6 shows the spectral characteristics of the emitted light from the light source unit 1 obtained under the above conditions. In the characteristics shown in FIG. 6, the horizontal axis is the wavelength, and the vertical axis is the intensity (arbitrary unit) of the emitted light. As is apparent from FIG. 6, under the above conditions, the emitted light includes a light component in the vicinity of a wavelength of 445 nm (blue light component) and a light component in a wavelength region extending over about 480 to 680 nm, that is, a red light component and a green light component. It can be seen that a light component including This also shows that white light is emitted from the light source device unit 1 of the present embodiment.

  As described above, in the present embodiment, white light can be emitted from the light source device unit 1 using a solid light emitting element. Therefore, the present embodiment can also be applied to applications that require a light source device that emits white light, such as a 3LCD projector. That is, in the present embodiment, it is possible to provide a mercury-less light source device unit 1 (illumination device) that can be applied to various uses and an image display device 10 including the same.

  Since the light source device unit 1 of this embodiment does not need to use a mercury lamp, it can cope with recent environmental problems. Further, in the present embodiment, it is possible to provide the light source device unit 1 and the image display device 10 that have a longer lifetime and a lower luminance reduction than the mercury lamp. Further, when a solid light emitting element is used as the excitation light source 11 as in the present embodiment, the lighting time can be further shortened as compared with a mercury lamp.

  Further, when a semiconductor laser is used as the excitation light source 11 as in the light source device unit 1 of the present embodiment, light with sufficiently high luminance is emitted even when compared with a solid light source such as an LED (Light Emitting Diode). Therefore, a high-intensity light source can be realized. Further, as in the present embodiment, the configuration in which the phosphor layer 32 is caused to emit light with a blue light laser to generate white light is prepared by separately preparing each solid light source of red light, green light, and blue light. It is simpler and cheaper than the configuration to be generated.

[6. Various modifications]
(1) Modification 1
In the present embodiment, the example in which the polarization beam splitter 12 is used to separate the excitation light incident on the fluorescent member 15 and the white light incident on the optical engine unit 2 has been described, but the present invention is not limited to this. For example, instead of the polarizing beam splitter 12, a reflection mirror configured to reflect blue light in a partial region may be used. An example (Modification 1) is shown in FIG.

  The reflection mirror 40 (spectral optical system) of Modification 1 includes a plate-like transparent substrate 41 (base material) and a reflection film 42 (second reflection film) formed on a part of one surface thereof. Is done. The reflective film 42 is formed with a size that is approximately the spot diameter of the excitation light. In this example, the reflection mirror 40 is disposed in the light source unit 1 so that the reflection film 42 is disposed at the excitation light irradiation position and the surface of the reflection mirror 40 is inclined by about 45 degrees with respect to the excitation light incident direction. To place.

  The transparent substrate 41 is formed of a transparent material such as glass or transparent resin, and the reflection film 42 can be formed of, for example, a dichroic mirror (dichroic film) as shown in FIG. When the reflective film 42 is composed of a dichroic mirror, only the blue light is selectively reflected by adjusting the formation material of each dielectric layer, the thickness of the dielectric layer, the number of stacked layers, and the like. The component can also be permeated. Further, the reflective film 42 may be formed of a metal film such as aluminum.

  When the reflection mirror 40 configured as shown in FIG. 7 is used, the excitation light from the excitation light source 11 is reflected by the reflection film 42 and is incident on the fluorescent member 15. On the other hand, the combined light (white light LW) incident on the reflection mirror 40 from the fluorescent member 15 via the condensing optical system 14 mainly passes through the region where the reflection film 42 is not formed, and the optical engine unit 2. Is incident on. When the reflective film 42 is designed to transmit light in a wavelength band other than blue light, the red light component and the green light component included in the combined light (white light LW) are also formed in the region where the reflective film 42 is formed. Pass through.

  In this example, when a semiconductor laser is used as the excitation light source 11, the spot diameter of the excitation light emitted from the excitation light source 11 is compared with that of the combined light (white light LW) emitted from the condensing optical system 14. Small enough. Therefore, even in the configuration of this example, the white light LW having a sufficiently large intensity can be emitted from the light source device unit 1.

  Further, as in this example, when the reflection mirror 40 is used as a spectroscopic optical system for separating the excitation light incident on the fluorescent member 15 and the combined light incident on the optical engine unit 2, The configuration can be simplified. Further, in the configuration of this example, it is not necessary to consider the polarization direction of the light incident on the reflection mirror 40, so that it is not necessary to provide the quarter wavelength plate 13 as in the above embodiment. Therefore, in this example, the configuration of the light source device unit 1 can be simplified, and the cheaper light source device unit 1 can be provided.

(2) Modification 2
In the above embodiment and the first modification, the spectroscopic optical system (the polarizing beam splitter 12 or the reflection mirror 40) reflects the excitation light emitted from the excitation light source 11 and transmits the combined light emitted from the fluorescent member 15. The example of making it explained was explained. However, the present invention is not limited to this.

  For example, the spectroscopic optical system is configured to transmit the excitation light emitted from the excitation light source 11 and guide it to the fluorescent member 15, and to reflect the combined light emitted from the fluorescent member 15 and guide it to the optical engine unit 2. May be. In this case, the excitation light incident on the polarization beam splitter 12 from the excitation light source 11 is converted to P-polarized light.

(3) Modification 3
In the above embodiment, an example in which the quarter wavelength plate 13 is provided in the light source device unit 1 has been described. However, the present invention is not limited to this, and for example, in applications that do not require high-output white light, The four-wave plate 13 may not be provided.

  When the quarter-wave plate 13 is not provided, S-polarized excitation light is directly incident on the phosphor layer 32 via the polarizing beam splitter 12 and the condensing optical system 14. In this case, part of the excitation light incident on the phosphor layer 32 is diffused in the phosphor layer 32, and the non-polarized excitation light component is reflected by the condensing optical system 14. Of the excitation light components reflected from the phosphor layer 32, only the P-polarized light component is transmitted through the polarization beam splitter 12. Further, since the excitation light component reflected from the reflection film 31 is S-polarized light, the excitation light component does not pass through the polarization beam splitter 12. Therefore, in the configuration of this example, white light including the P-polarized component of the excitation light reflected from the phosphor layer 32 and the emitted light from the phosphor layer 32 is emitted from the light source device unit 1.

  In the configuration of this example, the excitation light component included in the white light (combined light) emitted from the light source device unit 1 is only the P-polarized component reflected from the phosphor layer 32. Therefore, in this example, the intensity of the emitted light and the utilization efficiency of the excitation light are reduced as compared with the above embodiment. However, in the light source device unit 1 of this example, since it is not necessary to provide the quarter wavelength plate 13, the configuration is simpler than that in the above embodiment.

(4) Modification 4
In the above embodiment and Modification 1, an example in which excitation light incident on the fluorescent member 15 and combined light emitted from the fluorescent member 15 are separated using a spectroscopic optical system (the polarizing beam splitter 12 or the reflection mirror 40). However, the present invention is not limited to this. For example, when the excitation light is obliquely incident on the fluorescent member 15 and the combined light emitted from the fluorescent member 15 is collected by an optical path different from the incident optical path of the excitation light, the above-described spectroscopic optical system or 1 The / 4 wavelength plate 13 may not be provided. In this case, the configuration of the light source device unit 1 becomes simpler.

(5) Modification 5
In the above embodiment, the example in which the condensing optical system 14 is provided in the light source device 1 has been described, but the present invention is not limited to this. For example, when the light source device unit 1 of the present embodiment is applied to an application that does not require high output light, the light source device unit 1 may be configured without the condensing optical system 14.

(6) Modification 6
In the above embodiment, the example in which the emitted light of the light source device unit 1 (illumination device) is white light has been described, but the present invention is not limited to this. For example, in applications that require cyan light (or magenta light) as outgoing light, blue light may be used as excitation light, and the phosphor layer 32 may be formed of a fluorescent material that emits only green light (or red light). . That is, a combination of the wavelength of the excitation light and the material for forming the phosphor layer 32 may be appropriately selected according to the required wavelength (color) of the emitted light. In this case, the range of applicable uses can be further expanded.

  DESCRIPTION OF SYMBOLS 1 ... Light source device part, 2 ... Optical engine part, 10 ... Image display apparatus, 11 ... Excitation light source, 12 ... Polarizing beam splitter, 13 ... 1/4 wavelength plate, 14 ... Condensing optical system, 15 ... Fluorescent member, 16 DESCRIPTION OF SYMBOLS ... Motor, 20 ... Spectral optical system, 21 ... 1st LCD panel, 22 ... 2nd LCD panel, 23 ... 3rd LCD panel, 24 ... Prism, 25 ... Projection optical system, 30 ... Substrate, 31, 42 ... Reflective film, 32 ... Phosphor layer, 40 ... reflection mirror, 41 ... transparent substrate

Claims (24)

An excitation light source that emits excitation light including first color light;
A phosphor that converts at least a part of the excitation light into a second color light different from the first color light when the excitation light is incident, and an incident side of the excitation light with respect to the phosphor A fluorescent member having a reflective member provided on the opposite side;
A first polarization component is provided on an optical path between the excitation light source and the fluorescent member, and converts a second polarization component of the first polarization component and the second polarization component in the first color light into a first polarization component. A light source device comprising: the first color light converted into a component; and a quarter-wave plate that emits the second color light reflected by the reflecting member . The light source device according to claim 1 , wherein the ¼ wavelength plate converts a first polarization component in the first color light into a second polarization component by allowing the first color light to pass twice. Wherein the first polarization component is a P-polarized light component, the second polarization component is a light source apparatus according to claim 1 or 2 is S-polarized light component. The excitation light source, the light source device according to any one of claims 1 to 3 for emitting excitation light of the linearly polarized light. The light source device according to claim 4 , wherein the excitation light source emits excitation light of the second polarization component in the first color light as the linearly polarized excitation light. The first color light comprises a blue light component, the light source device according to any one of claims 1 to 5 wherein the second color light comprises a red light component and green light component. The fluorescent member, a light source device according to any one of claims 1 to 6 having a disc shape. A drive unit connected to a position corresponding to the center of the fluorescent member, and a drive unit that rotates the fluorescent member so that the irradiation position of the excitation light on the phosphor moves in the rotation circumferential direction with time; ,
Said drive unit, wherein the fluorescent member, in a state that is rotated in a predetermined direction in the irradiation surface of the excitation light of the phosphor, any one of claims 1 to 7 for irradiating the excitation light to the phosphor The light source device according to 1. Provided on the excitation light incident side of the fluorescent member, and condenses the excitation light emitted from the excitation light source so as to have a predetermined spot diameter on the phosphor, and is emitted by the phosphor to emit the fluorescence. the light source device according to any one of claims 1 to 8 further comprising an optical system, a for converting the emission light emitted from the member substantially parallel light. The reflecting member has a light source device according to any one of claims 1 to 9 for reflecting at least the second color light. The fluorescent member further includes a substrate,
The reflecting member has a light source device according to any one of claims 1 to 10 is disposed on the substrate. The light source device according to claim 11, citing claim 8, wherein the substrate by fixing the hub is fixed to the drive shaft. An excitation light source that emits excitation light including first color light;
A phosphor that converts at least a part of the excitation light into a second color light different from the first color light when the excitation light is incident, and an incident side of the excitation light with respect to the phosphor A fluorescent member having a reflective member provided on the opposite side;
A first polarization component is provided on an optical path between the excitation light source and the fluorescent member, and converts a second polarization component of the first polarization component and the second polarization component in the first color light into a first polarization component. A light source device having a first wavelength light converted into a component and a quarter wavelength plate for emitting the second color light reflected by the reflecting member ;
An image projection apparatus comprising: an image projection unit that generates predetermined image light using light emitted from the light source unit and projects the generated image light to the outside. The image projection device according to claim 13 , wherein the quarter-wave plate converts the first polarization component in the first color light into a second polarization component by allowing the first color light to pass twice. The image projection device according to claim 13, wherein the first polarization component is a P polarization component, and the second polarization component is an S polarization component. The excitation light source, an image projection apparatus according to any one of claims 13 to 15 for emitting the excitation light linearly polarized light. The image projection device according to claim 16 , wherein the excitation light source emits the excitation light of the second polarization component in the first color light as the linearly polarized excitation light. The first color light comprises a blue light component, the image projection apparatus according to any one of claims 13 to 17, wherein the second color light comprises a red light component and green light component. The fluorescent member, the image projection apparatus according to any one of claims 13 to 18 having a disc shape. A drive unit connected to a position corresponding to the center of the fluorescent member, and a drive unit that rotates the fluorescent member so that the irradiation position of the excitation light on the phosphor moves in the rotation circumferential direction with time; ,
Said drive unit, wherein the fluorescent member, in a state that is rotated in a predetermined direction in the irradiation surface of the excitation light of the phosphor, one of claims 13 to 19 for irradiating the excitation light to the phosphor The image projection apparatus described in 1. Provided on the excitation light incident side of the fluorescent member, and condenses the excitation light emitted from the excitation light source so as to have a predetermined spot diameter on the phosphor, and is emitted by the phosphor to emit the fluorescence. the image projection apparatus according to any one of claims 13 to 20 further comprising an optical system, a for converting the emission light emitted from the member substantially parallel light. The reflecting member, an image projection apparatus according to any one of claims 13 to 21 for reflecting at least the second color light. The fluorescent member further includes a substrate,
The reflecting member, an image projection apparatus according to any one of claims 13 to 22 are disposed on the substrate. The image projection apparatus according to claim 23, citing claim 20 wherein the substrate is fixed to the drive shaft by a fixed hub.

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