JP6818149B2 - Fluorescent wheels, light source devices, and projection devices - Google Patents

Description

The present invention relates to a fluorescence wheel, a light source device, and a projection device capable of suppressing a decrease in luminous efficiency.

The image displayed by a projection device such as a projector is easily affected by external light, and high illuminance is required to obtain a high-quality display. In order to project with high illuminance, it is necessary to increase the amount of light from the light source, and a light source that combines high energy density excitation light such as laser light and a phosphor is beginning to be used.

In Patent Document 1, it has a plurality of segment regions arranged in the circumferential direction, at least one of the plurality of segment regions is a reflection portion, and fluorescence that receives excitation light in the reflection portion and emits light in a predetermined wavelength band. A disk-shaped light emitting plate technique is disclosed in which a body layer is formed and at least one of a plurality of segment regions is a transmitting portion through which light is transmitted.

Japanese Patent No. 5655211

However, it may not be possible to obtain the desired fluorescence emission intensity (brightness) simply by causing the phosphor to emit light using high energy density excitation light such as laser light in an optical device or a projection device. This is because the emission efficiency is lower than that in the case of emitting light with low energy density excitation light due to the excitation energy density dependence of the phosphor. In the technique described in Patent Document 1, the energy excitation density of the phosphor is not taken into consideration.

One embodiment of the present invention has been made in view of such circumstances, and reduces the luminous efficiency by changing the concentration of the emission center element of the phosphor in the portion where the energy density of the excitation light is high and the portion where the energy density is low. It is an object of the present invention to provide a fluorescent wheel that can be suppressed.

In order to achieve the above object, one embodiment of the present invention has taken the following measures. That is, the fluorescent wheel of the embodiment of the present invention is a disk-shaped fluorescent wheel having a region that receives excitation light and fluoresces, and is arranged on the wheel substrate and the wheel substrate and has a predetermined emission center element. A first phosphor layer containing a fluorescent substance having a concentration and a second phosphor layer arranged on the wheel substrate and containing a phosphor having a concentration of a luminescent center element different from that of the phosphor contained in the first phosphor layer. The first fluorescent layer and the second fluorescent layer are arranged adjacent to each other or partially overlapped with each other, and the first fluorescent layer and the second fluorescent layer are arranged. The boundary of the surface of the phosphor layer is at least a part of the circumference.

According to one embodiment of the present invention, in the phosphor layer of the fluorescent wheel, the decrease in luminous efficiency is suppressed by changing the emission center element concentration of the phosphor in the portion where the energy density of the excitation light is high and the portion where the energy density of the excitation light is low. Can be done.

It is a schematic diagram of the fluorescent wheel which concerns on 1st Embodiment. It is a schematic diagram which enlarged the cross section of the phosphor layer part of the fluorescent wheel which concerns on 1st Embodiment. It is a schematic diagram which shows the cross section in the state which the fluorescent wheel which concerns on 1st Embodiment is fixed to the rotating shaft of a wheel motor. It is a figure which shows the crystal structure of YAG (Y ₃ Al ₅ O ₁₂ ). It is a schematic diagram which shows an example of the fluorescent wheel which concerns on 1st Embodiment. It is a schematic diagram which shows the cross section in the state which the fluorescent wheel which concerns on 1st Embodiment is fixed to the rotating shaft of a wheel motor. It is a graph which shows the example of the temperature dependence of the external luminous efficiency of a phosphor. It is a graph which shows the example of the intensity distribution of a Gaussian beam. It is a schematic diagram which shows an example of the fluorescent wheel which concerns on 2nd Embodiment. It is a schematic diagram which shows the cross section in the state which the fluorescent wheel which concerns on 2nd Embodiment is fixed to the rotating shaft of a wheel motor. It is a schematic diagram which shows the modification of the fluorescent wheel which concerns on 2nd Embodiment. It is a schematic diagram which shows the modification of the fluorescent wheel which concerns on 2nd Embodiment. It is a schematic diagram which enlarged and represented the cross section of the part provided with the fluorescent substance layer which represents an example of the fluorescent wheel which concerns on 3rd Embodiment. It is a figure which shows the relationship between the schematic diagram of FIG. 12 and the graph which shows the amount in the cross-sectional direction of each phosphor having a different concentration of a central element of light emission. It is a schematic diagram which enlarged the cross section of the part provided with the phosphor layer of the modification of the fluorescent wheel which concerns on 3rd Embodiment. It is a schematic diagram which shows the light source apparatus which concerns on 4th Embodiment. It is a conceptual diagram which shows the projection apparatus which concerns on 4th Embodiment. It is a conceptual diagram which shows the projection apparatus which concerns on 5th Embodiment.

The present inventors have found that a decrease in luminous efficiency can be suppressed by changing the concentration of the luminous center element of the phosphor in a portion where the energy density of the excitation light is high and a portion where the energy density is low, and have reached the present invention.

As a result, the present inventors have made it possible to obtain a desired fluorescence emission intensity (brightness) when the phosphor is emitted by using high energy density excitation light such as laser light. Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In order to facilitate understanding of the description, the same reference number is assigned to the same component in each drawing, and duplicate description is omitted.

[First Embodiment]
[Fluorescent wheel configuration]
FIG. 1 is a schematic view of a fluorescent wheel 100 according to this embodiment. As shown in FIG. 1, the fluorescent wheel 100 according to the present embodiment includes a wheel substrate 110 and a phosphor layer 130.

The wheel substrate 110 is formed in a disk shape and has a phosphor layer 130 on its surface. The wheel substrate 110 can be made of a metal such as aluminum, copper, or iron when it is of the reflective type, depending on the design of the light source device 200 using the wheel substrate 110. At this time, it is preferable that the surface of the wheel substrate 110 is coated with a highly reflective film such as silver. Further, the wheel substrate 110 may be formed of a material that does not consider the reflection of excitation light and fluorescence, and only the surface irradiated with the excitation light may be formed of a reflective material.

When the wheel substrate 110 is of the transmission type, it can be formed of an inorganic material such as sapphire or glass that transmits excitation light. Further, since the fluorescence emitted by the phosphor is radiated in all directions, it is preferable to reflect the fluorescence while transmitting the excitation light when the transmission type is used. Further, regardless of whether the wheel substrate 110 is a reflective type or a transmissive type, it is preferable that the wheel substrate 110 has a high thermal conductivity in order to suppress temperature quenching of the phosphor. Therefore, the wheel substrate 110 is preferably made of aluminum or sapphire. Further, the wheel substrate 110 may be a combination of a reflective type and a transmissive type.

FIG. 2 is a schematic view of an enlarged cross section of the phosphor layer portion of the fluorescent wheel according to the present embodiment. The phosphor layer 130 includes phosphor particles 120 and a binder 125, and the phosphor particles 120 are dispersed in the binder 125. The phosphor particles 120 absorb a predetermined excitation light and emit light in a predetermined wavelength band. Further, the phosphor particles 120 are phosphors that emit light in the same wavelength band with respect to the same excitation light, and a plurality of phosphors having different emission center element concentrations (described later) are used. A plurality of phosphor layers containing phosphors having different luminescence center element concentrations are provided on the surface of the wheel substrate 110 according to the illuminance of each irradiated portion in the portion irradiated with the excitation light (excitation light spot). Be done.

At this time, phosphors having different luminescence center element concentrations may be included, and adjacent phosphor layers may be partially overlapped. Further, the boundary between the fluorescent layer layers having different concentrations of the emission center elements that are adjacent to each other or partially overlap each other forms a surface, but the boundary (boundary line) appearing on the surface of the phosphor layer is at least a part of the circumference. The circumference referred to here is a circumference centered on the center of rotation of the wheel substrate 110. By doing so, depending on the illuminance of each irradiated portion of the excitation light, the surface of the phosphor layer having different emission center element concentrations provided on the surface of the wheel substrate 110 so as to be adjacent or partially overlapped. The boundary can be the same boundary with respect to the portion irradiated with the excitation light even if the fluorescence wheel 100 is rotated.

For example, a case where two types of phosphors having different luminescence center element concentrations are used will be described. As shown in FIG. 2, the first phosphor layer 131 and the second phosphor layer 132 containing the first phosphor 121 and the second phosphor 122 having different emission center element concentrations are the surfaces of the wheel substrate 110. Provided on top. FIG. 3 is a schematic view showing a cross section of the fluorescent wheel 100 according to the present embodiment in a state of being fixed to the rotating shaft 225 of the drive device (wheel motor) 220 by using the wheel fixture 230. As shown in FIGS. 1 and 3, the boundary between the surfaces of the first phosphor layer 131 and the second phosphor layer 132 provided so as to be adjacent to each other or partially overlap is at least a part of the circumference. There is. Therefore, the distance from the center of rotation to the boundary is constant, and even if the fluorescent wheel 100 is rotated, the boundary is the same with respect to the portion irradiated with the excitation light.

The phosphor is composed of a garnet-based material using alumina as a base material. As the garnet-based material, YAG: Ce (yellow luminescent phosphor), LuAG: Ce (green luminescent phosphor) and the like can be used. Phosphor is composed of the general formula _{(RE 1-x} Ce _x) substance represented by ₃ Al _{5 O 12,} RE preferably contains at least one element selected from rare earth element group. The concentration x of the luminescence center element Ce with respect to the rare earth RE is called the luminescence center concentration. As the phosphor, SiAlON, Zn ₂ SiO ₄ : Mn, (Y, Gd) BO ₃ : Tb, (Y, Gd) BO ₃ : Eu, YPVO ₄ : Eu and the like can be used. The above is an example, and the phosphor used in the fluorescent wheel 100 of the present invention is not limited to the above example.

(Notation of luminescence center element concentration)
In the present invention, phosphors generally abbreviated as YAG and LuAG are exemplified, but the notation of the concentration of the luminescent center element contained in those materials is defined as follows.

In the yellow luminescent phosphor YAG: Ce, the four basic constituent elements are yttrium (Y), aluminum (Al), oxygen (O), and cerium (Ce). The yellow-green luminescent phosphor LuAG: Ce is obtained by replacing all Y of YAG: Ce with lutetium (Lu). For the purpose of intentionally changing the emission color, a part of Y is replaced with another rare earth element or the like, and a part of Al is replaced with a similar element such as Ga. Furthermore, in addition to Ce, which is the central element of light emission, an appropriate amount is often introduced into the crystal as a co-activator, for example, for the purpose of improving luminous efficiency.

FIG. 4 is a diagram showing a crystal structure of YAG (Y ₃ Al ₅ O ₁₂ ). YAG is a crystal having a garnet structure as shown in FIG. 4, and is represented by a chemical formula of Y ₃ Al ₅ O ₁₂ . It is said that Y is most stable when it is in the 8-coordinated position and Al is in both the 4-coordinated and 6-coordinated positions. The luminescence center element Ce replaces a part of Y having the closest size.

When the concentration x of the luminescence center element Ce is considered as the amount of substitution with Y, the YAG phosphor activated by Ce is represented by the general formula (Y _1-x Ce _x ) ₃ Al ₅ O ₁₂ . In the present invention, for example, when x = 0.030, the ratio of Ce to the site occupied by Y and Ce is defined as "3.0 mol%".

Also as with YAG case of LuAG, when represented by the general formula _{(Lu 1-y Ce y)} 3 Al 5 O 12, as the ratio of Ce to the site occupied by the Lu and Ce, and "· · · mol%" It will be defined.

FIG. 5 is a schematic view showing an example of the fluorescent wheel 100 according to the present embodiment. Further, FIG. 6 is a schematic view showing a cross section of the fluorescent wheel 100 fixed to the rotating shaft 225 of the wheel motor 220. In the following description, the fluorescence wheel 100 including two types of phosphor layers, a phosphor layer 133 using a phosphor having a low emission center element concentration and a phosphor layer 134 using a phosphor having a high emission center element concentration. As will be described, there may be three or more types of phosphor layers using phosphors having different luminescence center element concentrations. The phosphor layer 133 using a phosphor having a low emission center element concentration is the emission center element concentration of the phosphor layer 133 having a low emission center element concentration, and the phosphor layer 134 using a phosphor having a high emission center element concentration. Is represented as a high phosphor layer 134.

It is known that the temperature characteristics of a phosphor change depending on the concentration of the luminescent center element. FIG. 7 is a graph showing an example of the temperature dependence of the external luminous efficiency of YAG: Ce. In general, at low temperatures, a phosphor having a high concentration of a central element of light emission has a high luminous efficiency, and a fluorescent substance having a low concentration of a central element of light emission has a lower luminous efficiency. However, since the luminous efficiency of a fluorescent substance having a low concentration of a central element of light emission is gradually reduced even at a high temperature, the luminous efficiency of a fluorescent substance having a low concentration of a central element of light emission may be higher at a high temperature.

When the phosphor is irradiated with excitation light, a part of it is converted into heat energy together with fluorescence emission, so that the higher the illuminance of the excitation light, the higher the temperature. Therefore, the phosphor layer 133 having a low emission center element concentration is provided in the irradiated portion where the illuminance of the excitation light is high, and the phosphor layer 134 having a high emission center element concentration is provided in the irradiation portion where the illuminance of the excitation light is low. By arranging in this way, the part that tends to become hot due to the irradiation of excitation light emits light while suppressing the decrease in luminous efficiency at high temperature, and the part that does not become so high due to irradiation with excitation light is high at low temperature. It emits light with luminous efficiency. As a result, it is possible to suppress a decrease in the overall luminous efficiency.

FIG. 8 is a graph showing an example of the intensity distribution of the Gaussian beam. As represented by the Gaussian beam, the intensity distribution of the laser beam on the plane orthogonal to the propagation direction of the beam is not uniform, the beam center is strong, and the beam edge is weak. Therefore, it is preferable to provide a phosphor layer 133 having a low emission center element concentration in a portion through which the beam center portion passes, and to provide a phosphor layer 134 having a high emission center element concentration in a portion through which the beam edge portion passes. ..

Therefore, as shown in FIGS. 5 and 6, the emission center element concentration is located on the side near the center (rotation center) and the side far from the center of the wheel substrate 110 with respect to the phosphor layer 133 having a low emission center element concentration. It is preferable to provide the phosphor layer 134 having a high concentration. By arranging in this way, when the fluorescent wheel is rotated, the phosphor layer 133 having a low emission center element concentration is arranged in the portion through which the beam center portion passes, and in the portion through which the beam edge portion passes. , The phosphor layer 134 having a high concentration of the luminescent center element will be arranged.

The fluorescent wheel according to the present embodiment can change the temperature characteristics of the phosphor according to the illuminance of each irradiated portion of the excitation light, and can suppress a decrease in luminous efficiency. Further, in the irradiated portion where the illuminance is high and the temperature tends to be high near the center of the excitation light, a phosphor whose temperature characteristics are unlikely to deteriorate even at a high temperature can be arranged, and a decrease in luminous efficiency can be suppressed.

[Second Embodiment]
[Fluorescent wheel configuration]
In the first embodiment, the phosphor layer 130 is provided in the entire circumferential direction of the wheel substrate 110, but in the present embodiment, the wheel substrate 110 has a plurality of segment regions, and at least one of them is provided. The segment region is provided with phosphor layers having different concentrations of emission center elements, and each of the segment regions can extract light having a different wavelength when the same excitation light is received.

Further, one or more of the plurality of segment regions may be a region in which the phosphor layer 130 is not provided and the excitation light is transmitted or reflected. As a result, the excitation light can be used as it is, and for example, the blue excitation light can be extracted as it is as blue light.

Further, at least two segment regions of the wheel substrate 110 include a phosphor layer 130 each containing a phosphor that emits light in different wavelength bands when receiving the same excitation light. As a result, light having a different wavelength can be extracted using the same excitation light. Of these phosphor layers 130, only one segment region may be provided with phosphor layers having different emission center element concentrations. This is because it is possible to suppress a decrease in luminous efficiency at least in that region.

FIG. 9 is a schematic view of an example of the fluorescent wheel 100 according to the present embodiment. Further, FIG. 10 is a schematic view showing a cross section of the fluorescent wheel 100 fixed to the rotating shaft 225 of the wheel motor 220. As shown in FIG. 9, the fluorescent wheel 100 according to the present embodiment includes a wheel substrate 110 and phosphor layers 130 and 140, and the wheel substrate 110 has a plurality of fan-shaped segment regions, and one segment region is The transmission portion 160 that transmits the excitation light is used.

The phosphor layer 130 and the phosphor layer 140 shown in FIG. 9 include phosphors that emit light in different wavelength bands when they receive the same excitation light. As a result, light having a different wavelength can be extracted using the same excitation light. Further, in the example shown in FIG. 9, only the phosphor layer 130 includes a phosphor layer having a different emission center element concentration (a phosphor layer 133 having a low emission center element concentration and a phosphor layer 134 having a high emission center element concentration). However, it is also possible to provide phosphor layers having different emission center element concentrations for the phosphor layers in two or more segment regions. Since the transmitting portion 160 transmits the excitation light, the excitation light can be used as it is.

11A and 11B are schematic views showing a fluorescent wheel 100 of a modified example of this embodiment. As shown in FIG. 11A, the regions divided in the circumferential direction are defined as a segment having phosphor layers 130 and 140 including phosphors emitting two different wavelength band lights and a transmission portion 160, respectively, and the phosphor layer 130. Both of the 140 may be configured to include phosphor layers having different emission center element concentrations. In FIG. 11A, the phosphor layer 133 and the phosphor layer 143 have a low emission center element concentration, and the phosphor layer 134 and the phosphor layer 144 have a high emission center element concentration. Further, as shown in FIG. 11B, the segments are a segment including phosphor layers 130, 140, and 150 containing phosphors that emit light in three different wavelength bands and a transmission unit 160, and all the phosphor layers emit light. It may be configured to include phosphor layers having different central element concentrations. In FIG. 11B, the phosphor layer 133, the phosphor layer 143, and the phosphor layer 153 have a low emission center element concentration, and the phosphor layer 134, the phosphor layer 144, and the phosphor layer 154 have a high emission center element concentration. Further, depending on the design of the light source device 200 and the projection device 300 using the fluorescent wheel 100, the transmission unit 160 may be a reflection unit or may not be a transmission unit 160.

In the fluorescent wheel according to the present embodiment, a plurality of light emission having different wavelengths can be obtained with one wheel, and in a segment including a first phosphor layer and a second phosphor layer, each portion irradiated with excitation light The temperature characteristics of the phosphor can be changed according to the illuminance of the above, and the decrease in luminous efficiency can be suppressed.

[Third Embodiment]
[Fluorescent wheel configuration]
In the present embodiment, in the first embodiment or the second embodiment, the portion including the phosphor layers having different emission center element concentrations is partially overlapped with the adjacent phosphor layers having different emission center element concentrations. It is provided. Then, at least a part of the overlapping portion is formed by being laminated so that the thickness of at least one of the phosphor layers in the stacking direction is inclined.

FIG. 12 is a schematic view showing an enlarged cross section of a portion of the fluorescent wheel 100 according to the present embodiment provided with the phosphor layer 130. As shown in FIG. 12, the fluorescent wheel 100 according to the present embodiment includes a wheel substrate 110 and a phosphor layer 130, and further has a portion that partially overlaps the adjacent phosphor layers having different emission center element concentrations. , The thickness of both phosphor layers in the overlapping portion in the stacking direction is laminated so as to be inclined. In FIG. 12, the phosphor layer 133 has a low emission center element concentration, and the phosphor layer 134 has a high emission center element concentration.

FIG. 13 is a diagram showing the relationship between the schematic view of FIG. 12 and the graph showing the amount in the cross-sectional direction of each phosphor having a different concentration of the luminescent center element. As can be seen from the graph of FIG. 13, by laminating the phosphor layers 133 and 134 having different emission center element concentrations so that the thickness in at least one stacking direction is inclined, the emission center element concentration can be increased. The abundance of different phosphors in the cross-sectional direction is inclined, and the main types of phosphors that contribute to light emission are gradually switched along the in-plane inclination direction. As a result, the change in the external quantum yield with respect to the temperature change depending on the energy density of the excitation light becomes more gradual, and the change in brightness in the excitation light spot can be reduced.

FIG. 14 is a schematic view showing an enlarged cross section of a portion of the fluorescent wheel 100 of the modified example of the present embodiment provided with the phosphor layer 130. As shown in FIG. 14, in the fluorescent wheel 100 according to the present embodiment, various laminated shapes can be considered, and at least one of the overlapping portions of the phosphor layers having different emission center element concentrations has an inclination in the thickness in the laminated direction. It may be laminated so as to be attached. Further, the number of phosphor layers having different luminescence center element concentrations may be three or more.

In the fluorescent wheel according to the present embodiment, the abundance of phosphors having different emission center element concentrations in the cross-sectional direction is inclined, and the types of the main phosphors contributing to light emission are gradually switched along the in-plane inclination direction. .. As a result, the change in the external quantum yield with respect to the temperature change depending on the energy density of the excitation light becomes more gradual, and the change in brightness in the excitation light spot can be reduced.

[Fourth Embodiment]
[Configuration of light source device]
This embodiment is an embodiment of a light source device using a fluorescent wheel according to the first to third embodiments, and a projection device using the light source device. FIG. 15 is a schematic view showing the light source device 200 according to the present embodiment. The light source device 200 according to the present embodiment includes an excitation light source 210, a fluorescence wheel 100, and a drive device 220. In addition to the above, FIG. 15 includes a lens and a mirror, which may not be provided depending on the design of the light source device 200. Further, the lens and the mirror may be integrated with the light guide optical system 310 (described later) of the projection device 300.

The excitation light source 210 irradiates the fluorescence wheel 100 with a predetermined wavelength band light (excitation light). The wavelength band of the excitation light emitted by the excitation light source 210 can use various ranges depending on the design of the light source device 200. For example, a blue light source can be used as the excitation light source for exciting phosphor particles such as YAG and LuAG, and a blue laser diode (LD) is preferable.

The fluorescence wheel 100 absorbs the excitation light emitted from the excitation light source 210, emits light in a predetermined wavelength band, or emits the excitation light as it is. The fluorescent wheel 100 is the fluorescent wheel 100 according to the first to third embodiments.

The drive device (wheel motor) 220 is controlled by an electric signal to rotate (rotate and stop) the fluorescent wheel 100 through the rotation shaft 225 of the drive device 220. As a result, the position of the phosphor layer 130 of the fluorescent wheel 100 irradiated with the excitation light changes, the phosphor layer 130 is prevented from being excessively heated, and the temperature quenching of the phosphor can be suppressed. Further, in the case of the phosphor layer 130, the transmitting portion 160, or the fluorescent wheel 100 including the reflecting portion, which emits different light when the same excitation light is received, different colors can be extracted.

The wheel fixture 230 fixes the fluorescent wheel 100 to the rotating shaft 225 of the drive device 220. The wheel fixture 230 is fixed by sandwiching the hole-side peripheral edge of the fluorescent wheel 100 in the thickness direction. The rotating shaft 225 is rotated around the central axis by the driving force of the driving device 220 to rotate the fluorescent wheel 100. The wheel fixture 230 is preferably made of metal. Any method may be used to fix the fluorescent wheel 100 to the rotating shaft 225. Further, in the above embodiment, as shown in FIGS. 3, 6 and 10, the fluorescent wheel 100 is fixed to the rotating shaft 225 by using the wheel fixture 230, but the fluorescent wheel 100 is fixed to the rotating shaft 225 by an adhesive or the like. It may be fixed to the rotating shaft 225 so that the wheel fixture 230 is not used.

[Projection device configuration]
FIG. 16 is a conceptual diagram showing the projection device 300 according to the present embodiment. The projection device 300 according to the present embodiment includes a light source device 200, a light guide optical system 310, a display element 320, a projection optical system 330, an input unit 340, and a control unit 350. The light source device 200 is the light source device 200 according to the above embodiment.

The light guide optical system 310 guides the light emitted from the light source device 200 to the display element 320. The light guide optical system 310 includes a plurality of mirrors 311 or a dichroic mirror 312, and a plurality of lenses (not shown in FIG. 16). In FIG. 16, the dichroic mirror 312 is also an element constituting the light source device 200.

The display element 320 displays using the light guided by the light guide optical system 310. The display element 320 is controlled by the control unit 350 and displays an image based on the data received by the input unit 340. As the display element 320, for example, a DMD (Digital Micromirror Device), a liquid crystal light valve, or the like can be used.

The projection optical system 330 projects the display of the display element 320 to the outside of the projection device 300. The projection optical system 330 is composed of a plurality of lenses (not described). In the projection optical system 330, a part of the lens is movable by a motor or the like, and the control unit 350 controls the lens to adjust the zoom, focus, and the like. The conceptual diagram showing the projection device 300 in FIG. 16 is an example, and the light guide optical system 310 and the projection optical system 330 are changed to various forms according to the design of the fluorescence wheel 100, the light source device 200, and the projection device 300. Will be done.

The input unit 340 receives the input of the data of the image to be projected, and delivers the input data to the control unit 350. The input unit 340 may receive data from a device other than the projection device 300. Further, the input unit 340 may be connected to the Internet or the like and receive data by communication. Further, the input unit 340 accepts an operation by the user and delivers the input operation data to the control unit 350.

The control unit 350 controls the light source device 200, the display element 320, and the projection optical system 330 in order to project an image based on the data received by the input unit 340. The light guide optical system 310 may be fixed, but may be configured to be controlled by the control unit 350.

The light source device according to the present embodiment can be a highly efficient light source device because the temperature characteristics of the phosphor can be changed according to the illuminance of each irradiated portion of the excitation light and the decrease in luminous efficiency can be suppressed. Further, the projection device according to the present embodiment can maintain a high projection illuminance by using a high-efficiency light source device, and can obtain a good projection image even in an environment with external light.

[Fifth Embodiment]
[Projection device configuration]
FIG. 17 is a conceptual diagram showing the projection device 300 according to the present embodiment. The projection device 300 according to the present embodiment includes a light source device 200, a light guide optical system 310, a display element 320, a projection optical system 330, a sensor 360, an input unit 340, and a control unit 350.

The light source device 200 includes an excitation light source 210, a fluorescence wheel 100 according to a second embodiment, and a drive device 220. These configurations are similar to the second and fourth embodiments.

The configuration of the light guide optical system 310, the display element 320, the projection optical system 330, and the input unit 340 is the same as that of the fourth embodiment.

The sensor 360 acquires information on the rotational position of the fluorescent wheel 100 of the light source device 200. The sensor 360 notifies the control unit 350 of the acquired position information.

The control unit 350 controls the light source device 200, the display element 320, the light guide optical system 310, and the projection optical system 330 in order to project an image based on the data received by the input unit 340. Further, the control unit 350 controls the output of the excitation light source 210 according to the gradation of the color and brightness of the projected image to be output and the position information of the fluorescence wheel 100 acquired by the sensor 360.

The projection device according to the present embodiment can suppress deterioration of the excitation light source and the fluorescence wheel by controlling the output of the excitation light according to the gradation of color and brightness. Further, since it is not necessary to attenuate unnecessary light, heat generation inside the projection device can be suppressed.

[Manufacturing method of fluorescent wheel]
Next, a method of manufacturing the fluorescent wheel will be described. First, a disc-shaped wheel substrate is prepared. The wheel substrate may be integrally formed of one material, or may be formed by combining a plurality of materials. Next, a plurality of phosphor pastes in which phosphors having different luminescence center element concentrations are dispersed in an organic binder or an inorganic binder are prepared.

Then, a phosphor paste having different emission center element concentrations is applied to the portion of the wheel substrate that is irradiated with the excitation light so that at least the surface boundary of the adjacent or overlapping paste is a part of the circumference. Any method may be used for applying the phosphor paste, and for example, a drawing method using a liquid quantitative discharge device, a screen printing method, a spray method, an inkjet method, or the like can be used. When manufacturing the fluorescent wheel according to the third embodiment, if a drawing method using a liquid quantitative discharge device is used, the thickness of the overlapping portion of the fluorescent substance layers having different emission center element concentrations can be easily inclined in the stacking direction. It is preferable because it can be laminated so as to be attached.

Then, the wheel substrate coated with the paste is fired or dried to prepare a phosphor layer. In this way, it is possible to manufacture a phosphor wheel in which the temperature characteristics of the phosphor are changed according to the brightness of each irradiated portion of the excitation light.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

One embodiment of the present invention can adopt the following configuration. That is, (1) the fluorescent wheel of the embodiment of the present invention is a disk-shaped fluorescent wheel having a region that receives excitation light and fluoresces, and is arranged on a wheel substrate and the wheel substrate to emit a predetermined light. It contains a first phosphor layer containing a phosphor having a central element concentration, and a phosphor arranged on the wheel substrate and having a different emission central element concentration from the phosphor contained in the first phosphor layer. A second fluorescent layer is provided, and the first fluorescent layer and the second fluorescent layer are arranged adjacent to each other or partially overlapped, and the first fluorescent layer and the second fluorescence are arranged adjacent to each other or partially overlapped. The boundary of the surface of the phosphor layer of the body layer is at least a part of the circumference.

As a result, the temperature characteristics of the phosphor can be changed according to the illuminance of each irradiated portion of the excitation light, and the decrease in luminous efficiency can be suppressed.

(2) Further, in the fluorescent wheel according to the embodiment of the present invention, the second phosphor layer is located on the side near the center and the side far from the center of the wheel substrate with respect to the first phosphor layer, respectively. The emission center element concentration of the phosphor formed and contained in the first phosphor layer is lower than the emission center element concentration of the phosphor contained in the second phosphor layer.

As a result, a phosphor whose temperature characteristics are unlikely to deteriorate even at a high temperature can be arranged in the irradiated portion where the illuminance is high and the temperature tends to be high near the center of the excitation light, and the decrease in luminous efficiency can be suppressed.

(3) Further, in the fluorescent wheel according to the embodiment of the present invention, the wheel substrate has a plurality of segment regions arranged in the circumferential direction, and the first phosphor layer is provided in at least one segment region. And the second phosphor layer is provided, and light having a different wavelength can be extracted from each of the segment regions when the same excitation light is received.

As a result, light emission having different wavelengths can be obtained with one wheel, and in the segment provided with the first phosphor layer and the second phosphor layer, the phosphor is charged according to the illuminance of each irradiated portion of the excitation light. The temperature characteristics can be changed, and the decrease in luminous efficiency can be suppressed.

(4) Further, in the fluorescence wheel according to the embodiment of the present invention, at least a part of the portion where the first phosphor layer and the second phosphor layer overlap is the first phosphor layer and the said. At least one of the second phosphor layers is laminated so that the thickness in the stacking direction is inclined.

As a result, the abundance of phosphors having different luminescence center element concentrations in the cross-sectional direction is inclined, and the types of main phosphors contributing to light emission are gradually switched along the in-plane inclination direction. As a result, the change in the external quantum yield with respect to the temperature change depending on the energy density of the excitation light becomes more gradual, and the change in brightness in the excitation light spot can be reduced.

(5) Further, the light source device according to the embodiment of the present invention includes an excitation light source that irradiates excitation light and a fluorescent wheel according to any one of (1) to (4) above that receives the irradiated excitation light. , A drive device for rotating the fluorescent wheel.

As a result, the temperature characteristics of the phosphor can be changed according to the illuminance of each irradiated portion of the excitation light, and the decrease in luminous efficiency can be suppressed. As a result, a highly efficient light source device can be configured.

(6) Further, the projection device according to the embodiment of the present invention is based on the light source device according to (5) above, a light guide optical system that guides light emitted from the light source device, and the light guide optical system. A display element that displays using the guided light, a projection optical system that projects the display to the outside, an input unit that receives input of data of the projected image, the light source device, the display element, and each of the optics. It includes a control unit that controls the system.

As a result, it is possible to maintain a high projected illuminance by using a highly efficient light source device, and it is possible to obtain a good projected image even in an environment with external light.

(7) Further, the projection device according to the embodiment of the present invention includes an excitation light source that irradiates excitation light, the fluorescent wheel according to (3) above that receives the irradiated excitation light, and a drive that rotates the fluorescent wheel. A light source device including a device, a light guide optical system that guides light emitted from the light source device, a display element that displays using the light guided by the light guide optical system, and the display. Acquires a projection optical system for projecting to the outside, an input unit for receiving input of image data to be projected, a control unit for controlling the light source device, the display element, and each optical system, and a rotational position of the fluorescent wheel. The control unit includes a sensor, and the control unit controls the output of the excitation light source according to the gradation of the color and brightness of the projected image to be output and the position information of the fluorescent wheel acquired by the sensor.

As a result, deterioration of the excitation light source and the fluorescence wheel can be suppressed by controlling the output of the excitation light according to the gradation of color and brightness. Further, since it is not necessary to attenuate unnecessary light, heat generation inside the projection device can be suppressed.

This international application claims priority based on Japanese Patent Application No. 2017-144649 filed on July 26, 2017, and includes the entire contents of Japanese Patent Application No. 2017-144649. Incorporate for international applications.

100 Fluorescent wheel 110 Wheel substrate 120 Fluorescent particle 121 First phosphor 122 Second phosphor 125 Binder 130, 140, 150 Fluorescent layer 131 First fluorescent layer 132 Second fluorescent layer 133, 143, 153 Fluorescent layer with low concentration of luminescent center element 134, 144, 154 Fluorescent layer with high concentration of luminescent center element 160 Transmitter 200 Light source device 210 Excitation light source 220 Drive device 225 Rotating shaft 230 Wheel fixture 300 Projection device 310 Guide optics System 311 Mirror 312 Dycroic Mirror 320 Display element 330 Projection optical system 340 Input unit 350 Control unit 360 Sensor

Claims (7)

A disk-shaped fluorescent wheel having a region that fluoresces in response to excitation light.
With the wheel board
A first phosphor layer, which is arranged on the wheel substrate and contains a phosphor having a first emission center element concentration,
A second phosphor layer, which is arranged on the wheel substrate and contains a phosphor having a second emission center element concentration, is provided.
The first phosphor layer and the second phosphor layer are arranged adjacent to each other or partially overlapped with each other.
The boundary between the surface of the first phosphor layer and the surface of the phosphor layer of the second phosphor layer is at least a part of the circumference.
A fluorescent wheel in which the concentration of the first emission center element and the concentration of the second emission center element are different . A disk-shaped fluorescent wheel having a region that fluoresces in response to excitation light.
With the wheel board
A first phosphor layer arranged on the wheel substrate and containing a phosphor having a predetermined emission center element concentration,
A second phosphor layer, which is arranged on the wheel substrate and contains a phosphor having a concentration of a emission center element different from that of the phosphor contained in the first phosphor layer, is provided.
The first phosphor layer and the second phosphor layer are arranged adjacent to each other or partially overlapped with each other.
The boundary between the surface of the first phosphor layer and the surface of the phosphor layer of the second phosphor layer is at least a part of the circumference.
The second phosphor layer is formed on the side near the center and the side far from the center of the wheel substrate with respect to the first phosphor layer, respectively.
A fluorescent wheel in which the concentration of the emission center element of the phosphor contained in the first phosphor layer is lower than the concentration of the emission center element of the phosphor contained in the second phosphor layer. A disk-shaped fluorescent wheel having a region that fluoresces in response to excitation light.
With the wheel board
A first phosphor layer arranged on the wheel substrate and containing a phosphor having a predetermined emission center element concentration,
A second phosphor layer, which is arranged on the wheel substrate and contains a phosphor having a concentration of a emission center element different from that of the phosphor contained in the first phosphor layer, is provided.
The first phosphor layer and the second phosphor layer are arranged adjacent to each other or partially overlapped with each other.
The boundary between the surface of the first phosphor layer and the surface of the phosphor layer of the second phosphor layer is at least a part of the circumference.
At least a part of the portion where the first fluorescent layer and the second fluorescent layer overlap is the stacking direction of at least one of the first fluorescent layer and the second fluorescent layer. Fluorescent wheel that is laminated and formed so that the thickness of the wheel is inclined. The wheel substrate has a plurality of segment regions arranged in the circumferential direction.
The first fluorescent layer and the second fluorescent layer are provided in at least one segment region.
The fluorescent wheel according to any one of claims 1 to 3, wherein different lights can be extracted from each of the segment regions when the same excitation light is received. An excitation light source that irradiates excitation light,
The fluorescent wheel according to any one of claims 1 to 4, which receives the irradiated excitation light.
A light source device including a drive device for rotating the fluorescent wheel. The light source device according to claim 5 and
A light guide optical system that guides the light emitted from the light source device, and
An input section that accepts input of projected image data,
A display element that displays an image of data input to the input unit using light guided by the light guide optical system, and a display element.
A projection optical system that projects the display to the outside,
A projection device including the light source device, the display element, and a control unit that controls each of the optical systems. A light source device including an excitation light source that irradiates excitation light, a fluorescence wheel according to claim 4 that receives the irradiated excitation light, and a drive device that rotates the fluorescence wheel.
A light guide optical system that guides the light emitted from the light source device, and
An input section that accepts input of projected image data,
A display element that displays an image of data input to the input unit using light guided by the light guide optical system, and a display element.
A projection optical system that projects the display to the outside,
A control unit that controls the light source device, the display element, and each optical system,
A sensor for acquiring the rotational position of the fluorescent wheel is provided.
The control unit is a projection device that controls the output of the excitation light source according to the gradation of the color and brightness of the projected image to be output and the position information of the fluorescent wheel acquired by the sensor.

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