JP2019057493A - Illumination device and projection type image display device - Google Patents

Abstract

To provide a phosphor wheel device capable of achieving high reliability that does not cause peeling destruction even when a fluorescence substance is subjected to powerful excitation energy.SOLUTION: A phosphor wheel device 118 used for a fluorescent illumination device as an illumination device includes: a blue-color laser diode unit which is an excitation light source; a fluorescence substance 119 that receives an excitation light from the excitation light source and emits a light; a spreader 121 made of a material having high thermal conductivity; and a reflection layer 120 provided between the fluorescence substance and the spreader, which has characteristics to reflect a light of fluorescent wavelength of the fluorescence substance. The fluorescence substance is composed of a plurality of fluorescence substance pieces 119a-119h of the same characteristics arranged adjacent to each other on the spreader.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to an illumination device using a phosphor and a projection display apparatus using the same as a light source.

  Japanese Patent Application Laid-Open No. 2004-228561 discloses that the divided phosphors are shielded by a light absorbing material and control the directionality of light emission as a control specification. However, assuming the emission intensity assumed for lighting or the like, heat generation of the light absorbing material is disclosed. Becomes remarkable, and is not realistic due to the temperature quenching characteristics of the phosphor. Patent Document 2 discloses a technique in which a more aggressive wall is provided at the interface between phosphors, and this wall is configured as a metal reflecting surface. This was also characterized by the interface between adjacent phosphors. In addition, the presence of metals with different thermal expansions at the interface makes it unstable in terms of reliability.

  In both cases, different materials are interposed between the phosphors, and the excitation light incident thereon is wasted, resulting in a clear reduction in efficiency.

JP 2012-129135 A JP 2013-102078 A

  Provided is a lighting device capable of realizing high reliability that does not cause delamination even when a phosphor receives strong excitation energy.

  An illumination device according to the present disclosure is provided between an excitation light source, a phosphor that receives excitation light from the excitation light source and emits fluorescent light, a spreader that supports the phosphor, and the phosphor and the spreader. A reflective layer that reflects. The phosphor is configured by arranging a plurality of phosphor pieces having the same characteristics adjacent to each other.

  The illumination device of the present disclosure can realize high reliability that does not cause delamination even when the phosphor receives strong excitation energy.

The figure which shows the projection type video display apparatus of Embodiment 1 using a fluorescent substance wheel apparatus. Diagram showing phosphor wheel device The figure which shows the projection type video display apparatus of Embodiment 2 using a fixed fluorescent substance apparatus. Diagram showing fixed phosphor device

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, the first embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a projection display apparatus 10 using a phosphor illumination device 100 having a phosphor wheel device 118 as a light source. 2A and 2B are diagrams showing the phosphor wheel device 118. FIG. 2A is a front view of the phosphor wheel device 118, and FIG. 2B is a side view of the phosphor wheel device 118. FIG. The hatching in FIG. 2 is given for understanding the configuration and does not indicate a cross section.

  In FIG. 1, the blue laser diode units 101a and 101b for the light source are composed of a plurality of blue laser diodes and collimating lenses arranged on the emission surface side corresponding to the respective lasers, and suppress the spread of the laser light. Can be output. Here, the blue laser diode units 101a and 101b are an example of an excitation light source.

  The blue laser light emitted from the blue laser diode unit 101a is incident on the mirror 102 having a partial opening. By entering here, a part of the light is emitted in the + X direction through the opening of the mirror 102 having a partial opening, and the light incident on the reflecting portion is reflected in the + Y direction. The light emitted from the blue laser diode unit 101b also enters the mirror 102 having a partial opening. Similarly, by entering the light beam, a part of the light passes through the opening of the mirror 102 having a partial opening and is emitted in the + Y direction, and the light incident on the reflecting portion is reflected in the + X direction. Of the light emitted from the blue laser diode units 101a and 101b, the aperture shape of the mirror 102 having a partial aperture is designed so that the ratio of the light traveling in the + X direction and the light traveling in the + Y direction is higher. Yes.

  The blue light emitted in the + X direction is collected by the lens 103, reflected by the mirror 104, and then collected near the diffusion plate 105. The light incident on the condenser lens 106 becomes substantially parallel light and enters the dichroic mirror 107. Since the dichroic mirror 107 has a characteristic of transmitting blue light and reflecting other color lights, and the blue laser light is blue light, the blue laser light is transmitted therethrough. The transmitted blue laser light passes through the lens 108, the mirror 109, and the lens 110 and is condensed on the incident surface of the rod integrator 111 having a rectangular opening.

  The light traveling in the + Y direction through the mirror 102 having a partial aperture is converged by the lens 112 and the lens 113 constituting the afocal system with the mirror 114 interposed therebetween, and is incident on the diffusion plate 115. The blue laser light incident on the diffusion plate 115 is diffused here and then passes through the dichroic mirror 107 and enters the condenser lenses 116 and 117. The blue laser light incident here enters the phosphor 119 of the phosphor wheel device 118 as excitation light.

  As shown in FIG. 2, the phosphor 119 of the phosphor wheel device 118 has phosphor sections 119a to 119h having the same characteristics, but their sections (surfaces perpendicular to the paper surface) abut each other, They are arranged in close proximity. These phosphor pieces are ceramic phosphors made of YAG phosphors, and have the property of emitting yellow light when receiving excitation light. A reflection layer 120 having a characteristic of reflecting light having a wavelength of fluorescent light (fluorescence wavelength) is formed on the surface of the phosphor piece opposite to the excitation light incident surface. The reflective layer 120 is formed on the surface of a spreader 121 made of a material having excellent thermal conductivity, and is fixed by a light-transmitting adhesive layer 122 provided between the reflective layer 120 and the spreader 121.

  The spreader 121 is generally called a heat spreader, and the spreader 121 of the present embodiment has a disk shape, and a plurality of phosphor pieces 119a to 119h are annular in the circumferential direction on the surface of the reflective layer formed on the spreader. A motor 123 is provided adjacent to each other so as to form a shape, and the spreader is rotatable at the center of the spreader.

  The blue laser light is converted into yellow light by entering the phosphor, is reflected by the reflective layer on the back surface, and is emitted to the condenser lens 117 side. The yellow light that has passed through the condenser lens 117 passes through the condenser lens 116 and is incident on the dichroic mirror 107. Similar to the blue laser light (blue light) reflected here and transmitted through the dichroic mirror 107, the yellow light passes through the lens 108, the mirror 109, and the lens 110 and is condensed on the incident surface of the rod integrator 111 having a rectangular opening. Here, the blue light of the laser light source and the yellow light of the fluorescent light are superimposed to form white light.

  The light emitted from the rod integrator 111 is reflected by the folding mirror 126 via the relay lenses 124 and 125, and then enters the total reflection prism 128 via the field lens 127. The total reflection prism 128 is formed by fixing a first prism 129 and a second prism 130 while maintaining a slight gap. The light incident on the total reflection prism 128 is totally reflected by the surface 131 and then enters the color prism unit 133 via the surface 132.

  The color prism unit 133 includes a first prism 135 having a dichroic mirror surface 134 having a characteristic of reflecting blue light, and a second prism having a dichroic mirror surface 136 having a characteristic of reflecting red light. 137 and a third prism 138 are bonded and fixed. As shown in FIG. 1, DMDs (digital micromirror devices) 139R, 139G, and 139B are provided on the end faces of the prisms. In these DMDs, minute mirrors corresponding to pixels are two-dimensionally arranged, and the tilting direction is controlled in two directions according to the video signal from the outside. Reflected light returns to the color prism unit 133 at an incident angle of 0 ° at the tilt angle at the ON signal, and is incident again at a large angle at the OFF signal. DMD 139B is for blue light modulation, DMD 139R is for red light modulation, and DMD 139G is for green light modulation. As described above, the DMD is an example of an image display element that generates image light by modulating the light emitted from the phosphor illumination device 100 with the image signal.

  In each pixel of DMD 139R, 139G, and 139B, the color light corresponding to the ON signal returns to color prism unit 133 again, passes through first prism 129 and second prism 130 of total reflection prism 128, and passes through projection lens 140. The projection lens enlarges and projects the image light generated by the DMD onto a screen (not shown) to realize color display.

  There is a possibility that a slight gap is formed at the abutting portion between the phosphor pieces 119a to 119h, but the surface of the phosphor 119 on which the spot pattern of the excitation light is formed and the screen surface on which the image light is projected are conjugate. Since it is not related, the gap shape is not projected. However, since it is impossible to deny the possibility of slight deterioration in the output of the fluorescent light, if it is not acceptable, the phosphor wheel device is provided with a rotation detection sensor 141 for detecting the rotational position of the disk-shaped spreader, or the motor itself. By providing a rotation position detection function and synchronizing the rotation timing of the spreader with the output of the excitation light or the control by the video signal, a slight luminance change can be corrected.

  As described above, the rotation detection sensor 141 is an example of a detection unit that detects a rotation position of a butt portion of a plurality of phosphor pieces on a disk-shaped spreader. In the phosphor illumination device 100, the incident position of excitation light is fluorescent. It has a function of changing the output of the image display and suppressing the luminance change at the timing to reach the butting part of the body piece. In order to suppress the luminance change of the image light by changing the output of the image display, for example, the excitation light output is raised to the fluorescent light at the timing when the incident position of the excitation light reaches the butt portion of the phosphor piece. The output of yellow light may be corrected, or control for emphasizing yellow in video signal control may be performed.

Here, the light incident on the phosphor pieces 119a to 119h has high energy. On the other hand, since the conversion efficiency of the phosphor is about 50%, half of the incident energy becomes heat. The thermal expansion coefficient of the YAG phosphor is 4 × 10 ⁻⁶ / ° C., and when the spreader is made of an aluminum material, the thermal expansion coefficient is 24.5 × 10 ⁻⁶ / ° C. There is a concern that distortion occurs between the phosphor and the spreader, which may cause peeling. By configuring the phosphor with a plurality of phosphor pieces 119a to 119h as in this embodiment, even if the temperature rises, the space between the phosphor pieces 119a to 119h is slightly opened, and the stress is released here. It will not lead to destruction. The number of divisions of the phosphor pieces is desirably determined from the temperature rise and the difference in thermal expansion coefficient of the material. In addition, the gap between the phosphor pieces slightly reduces the conversion efficiency of incident light, but the excitation light incident on the phosphor is a spot light having a certain area and does not affect the final image. .

  In the above configuration, the phosphor pieces 119a to 119h are fixed to the spreader 121 via the adhesive layer 122. In practice, the thermal conductivity is often inferior at the adhesive layer portion. Since it is not expected that the adhesive layer has a function of absorbing stress, the adhesive layer can be made very thin. Here, a reflective layer is provided on the phosphor side, and the order is the adhesive layer and the spreader. However, if the adhesive layer is made of a light-transmitting material and is transparent, the order of the reflective layer and the adhesive layer can be switched. In the case where the adhesive layer has reflection characteristics, it is not necessary to provide a reflection layer separately. Therefore, an adhesive layer having reflection characteristics formed by adding a reflective material to a light-transmitting adhesive may be used without separately providing the reflective layer and the adhesive layer.

  Further, although the spreader 121 is made of an aluminum material here, it is also possible to use a metal having a high thermal conductivity, such as a copper material, and having excellent thermal conductivity.

  Furthermore, it is desirable that the spreader 121 is made of ceramic (silicon carbide or silicon nitride) which is a material having a thermal expansion coefficient close to that of a phosphor and excellent in thermal conductivity. In either case, the thermal expansion coefficient is the same level as that of the phosphor, but the thermal conductivity is more desirable because silicon carbide is a numerical value close to that of aluminum. According to these, since the generation of stress due to the difference in thermal expansion between the spreader and the phosphor can be suppressed, the thickness of the adhesive layer 122 for adhering the phosphor piece to the spreader can be suppressed. This leads to a reduction in temperature rise of the phosphor irradiated with the excitation light. Further, depending on the operating temperature range, processing can be performed by means such as diffusion bonding that does not require an adhesive layer. Since diffusion bonding is performed by diffusion of atoms of materials at pressure and temperature, there is no adverse effect on thermal conductivity as in the case of using an adhesive, and a more excellent heat dissipation structure can be realized. Needless to say, if the phosphor can be formed directly on the ceramic spreader even if it is an inorganic material, the phosphor can be constructed without using bonding or bonding means such as diffusion bonding. In this way, the phosphor pieces can be fixed by diffusion bonding with the reflection layer sandwiched between the spreaders.

  In the case of bonding, it is possible to fix phosphor pieces by soldering or silver brazing, which is not an adhesive, and cannot be expected to have a stress releasing effect.

  The phosphor lighting device 100 can be configured as a lighting device, and can obtain white light. Therefore, the phosphor lighting device 100 can be used not only for a projection display apparatus but also for general lighting. The phosphor lighting device 100 is particularly characterized by the configuration of the phosphor wheel device 118, and is not limited to the configuration of the optical path of excitation light or the configuration from the phosphor wheel device to the rod integrator.

  Here, the phosphor 119 is configured by arranging a plurality of phosphor pieces having the same characteristics on a disc-shaped spreader 121. However, for example, in the case of a projection-type image display device that displays color of image light in a time division manner, It is possible to arrange two or three kinds of phosphors that emit different colored lights on the spreader 121. In this case, the same effect as described above can be obtained by configuring the phosphors of the respective color lights as an aggregate of a plurality of phosphor pieces in the same manner as described above.

  In order to obtain higher output light, it is possible to configure an illuminating device that is equipped with two phosphor wheel devices and disperses the thermal load to optically synthesize fluorescent light. As described above, when excitation light is incident on the abutting portion of the phosphor piece, the possibility that the output of the fluorescent light slightly decreases cannot be denied. When using a plurality of phosphor wheel devices each having a disk-shaped spreader in which a plurality of phosphor pieces are arranged in an annular shape, the timing at which excitation light enters the abutting portions of the phosphor pieces of the plurality of phosphor wheel devices Thus, by controlling the rotation of the spreader, it is possible to make it difficult to detect a decrease in the output of fluorescent light.

(Embodiment 2)
Hereinafter, the second embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a diagram showing a projection display apparatus 20 using a phosphor illumination device 200 having a fixed phosphor device 201. 4A and 4B are diagrams showing the fixed phosphor device 201. FIG. 4A is a front view of the fixed phosphor device 201, and FIG. 4B is a side view of the fixed phosphor device 201. FIG. . The hatching in FIGS. 3 and 4 is provided for understanding the configuration and does not indicate a cross section.

  FIG. 3 is obtained by replacing the phosphor wheel device 118 in FIG. 1 with a fixed phosphor device 201, and thus description of the optical configuration other than the fixed phosphor device is omitted.

  As shown in FIG. 4, the phosphor 202 of the fixed phosphor device 201 is configured such that phosphor sections 202 a to 202 d having the same characteristics are arranged close to each other in cross section (surface perpendicular to the paper surface). In the second embodiment, four substantially square-shaped phosphor pieces are adjacently arranged in two dimensions (vertical and horizontal directions) to form a substantially square-shaped phosphor 202. These phosphor pieces are ceramic phosphors that are ceramic plates made of an inorganic material. A reflection layer 203 that reflects light having a wavelength of fluorescent light is formed on the surface of the phosphor 202 opposite to the excitation light incident surface. The reflective layer 203 is fixed via a spreader 204 having excellent thermal conductivity and an adhesive layer 205. A heat sink 206 is in close contact with the surface of the spreader 204 opposite to the surface on which the phosphor pieces are fixed. In addition, a configuration in which heat can be radiated by a cooling means (not shown) may be disposed in a portion other than the portion where the phosphor 202 of the fixed phosphor device 201 is equipped.

  The spot size of the excitation light formed by the condenser lenses 116 and 117 needs to be formed within the range of the phosphor pieces 202a to 202d, but when the excitation light is irradiated only near the center of the phosphor 202. Since temperature nonuniformity occurs in each phosphor piece, it is most desirable that the excitation light spot is inscribed in the range of the phosphor. The shape of the phosphor formed by arranging a plurality of phosphor pieces adjacent to each other may be configured to be, for example, a rectangular shape or a circular shape other than a square shape according to the spot shape of the excitation light.

  The fluorescent light generated by the fixed phosphor device 201 is also reflected by the reflective layer 203 on the back surface and emitted to the condenser lens 117 side. The subsequent operation is the same as that of the phosphor illuminating device 100 of the first embodiment, and the description thereof is omitted.

  By configuring the fixed phosphor device in this manner, there is no rotating parts (excluding the cooling fan), reliability and noise reduction can be obtained, and the size can be reduced by the configuration of the cooling means. Further, the cost can be reduced by the simplification of the configuration.

  In addition, the phosphor pieces 202a to 202d are fixed to the spreader 204 through the adhesive layer 205. In practice, the thermal conductivity is often inferior at this portion, but as described above, it is a small piece that is easy to release stress strain. In the case of a structure of a certain phosphor piece aggregate, the adhesive layer is not expected to have a function of absorbing stress, and thus the adhesive layer can be made extremely thin.

  Furthermore, it is desirable that the spreader 204 is made of ceramic (silicon carbide or silicon nitride) which is a material having a thermal expansion coefficient close to that of a phosphor and excellent in thermal conductivity. In either case, the thermal expansion coefficient is the same level as that of the phosphor, but the thermal conductivity is more desirable because silicon carbide is a numerical value close to that of aluminum. According to these, since the generation of stress due to the difference in thermal expansion between the spreader and the phosphor can be suppressed, the thickness of the adhesive layer 205 for adhering the phosphor piece to the spreader can be suppressed. This leads to a reduction in temperature rise of the phosphor irradiated with the excitation light. Further, depending on the operating temperature range, processing can be performed by means such as diffusion bonding that does not require an adhesive layer. Since diffusion bonding is performed by diffusion of atoms of materials at pressure and temperature, there is no adverse effect on thermal conductivity as in the case of using an adhesive, and a more excellent heat dissipation structure can be realized. Needless to say, if the phosphor can be formed directly on the ceramic spreader even if it is an inorganic material, the phosphor can be constructed without using bonding or bonding means such as diffusion bonding.

  Further, it is possible to replace the adhesive layer with solder or silver brazing as in the first embodiment. Further, the characteristics of the adhesive layer, such as providing the adhesive layer with a reflection characteristic, and forming the adhesive layer with a light-transmitting material, the positions of the adhesive layer and the reflective surface, and the related matters are the same as in the first embodiment. It can be changed.

  Note that the phosphor lighting device 200 can be configured as a lighting device and can obtain white light, so that it can be used not only for a projection display but also for general lighting. The phosphor illumination device 200 is particularly characterized by the configuration of the fixed phosphor device 201 and is not limited to the optical path of excitation light or the configuration from the fixed phosphor device to the rod integrator.

  In the above-described configuration, the spreader 204 and the heat sink 206 are separately configured. However, a cooling unit may be provided inside the spreader 204 and configured as a single component. In this case, the thermal resistance at the contact surface is eliminated, which is advantageous for cooling.

  Further, the cooling means here is a heat sink, but is not limited to this. If the heat receiving part of the heat pipe or the liquid cooling device is replaced with the above-described spreader 204, it is possible to cope with larger input energy.

  Up to this point, the cooling has been performed on the surface opposite to the phosphor piece fixing surface of the spreader 204. However, the phosphor piece periphery on the surface on which the phosphor piece is fixed or the phosphor piece is directly cooled by another cooling means. May be.

  As described above, the embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments that have been changed, replaced, added, omitted, and the like. Moreover, it is also possible to combine each component demonstrated in the said embodiment and it can also be set as a new embodiment.

  The present disclosure can be applied to an illumination device and a projection display apparatus using a ceramic phosphor.

10, 20 Projection-type image display device 100, 200 Phosphor illuminating device 101a, 101b Blue laser diode unit 102 Mirror 103, 108, 110, 112, 113 Lens 104, 109, 114, 126 Mirror 105, 115 Diffuser 106, 116 117 condenser lens 107 dichroic mirror 111 rod integrator 118 phosphor wheel device 119, 202 phosphor 119a, 119b, 119c, 119d, 119e, 119f, 119g, 119h, 202a, 202b, 202c, 202d phosphor piece 120, 203 reflection Layer 121, 204 Spreader 122, 205 Adhesive layer 123 Motor 124, 125 Relay lens 127 Field lens 128 Total reflection prism 129 Total reflection prism First prism 130 second prism 131, 132 surface 133 color prism unit 134, 136 dichroic mirror surface 135 first prism 137 color prism second prism 138 third color prism Prism 139R, 139G, 139B DMD
140 Projection Lens 141 Rotation Detection Sensor 201 Fixed Phosphor Device 206 Heat Sink

Claims (16)

An excitation light source;
A phosphor that emits fluorescent light in response to excitation light from the excitation light source;
A spreader for supporting the phosphor;
A reflection layer provided between the phosphor and the spreader and reflecting the fluorescent light; and
The said fluorescent substance is an illuminating device comprised by arrange | positioning the several fluorescent substance piece of the same characteristic adjacently. The spreader has a disk shape,
The plurality of phosphor pieces are arranged in a circumferential direction of the spreader to form an annular shape,
A motor is provided at the center of the spreader so that the spreader can rotate.
The lighting device according to claim 1.   The lighting device according to claim 1, wherein the reflective layer is formed on a surface of the phosphor, and an adhesive layer is provided between the reflective layer and the spreader.   The lighting device according to claim 1, wherein the reflection layer is formed on the surface of the spreader, and a light-transmitting adhesive layer is provided between the phosphor and the reflection layer.   The lighting device according to claim 1, wherein the reflective layer is formed by adding a reflective material to a light-transmitting adhesive.   The lighting device according to claim 1, wherein the phosphor is made of an inorganic material.   The lighting device according to claim 6, wherein the phosphor is a ceramic plate made of an inorganic material.   The lighting device according to claim 1, wherein the spreader is made of an aluminum material.   The lighting device according to claim 1, wherein the spreader is made of a copper material.   The lighting device according to claim 1, wherein the spreader is made of silicon carbide. The excitation light source is a blue laser;
The phosphor receives the light of the blue laser as the excitation light and emits yellow light.
The lighting device according to claim 1.   The lighting device according to claim 1, wherein the phosphor is fixed to the spreader by diffusion bonding with the reflective layer interposed therebetween.   The lighting device according to claim 1, wherein the spreader is fixed and has a cooling unit on a surface other than a portion where the phosphor is equipped or on the inside of the spreader. A lighting device according to claim 1;
An image display element for generating image light by modulating light emitted from the illumination device with an image signal;
A projection lens for enlarging and projecting the image light generated by the image display element,
Projection display device. A lighting device according to claim 2;
Detecting means for detecting a rotational position of a butting portion formed between the plurality of phosphor pieces adjacent to each other;
An image display element for generating image light by modulating light emitted from the illumination device with an image signal;
A projection lens for enlarging and projecting the image light generated by the image display element,
Based on the rotation position of the abutting portion detected by the detecting means, the output of the image display is changed at the timing when the excitation light incident position reaches the abutting portion, thereby suppressing the luminance change of the video light. Projection-type image display device. A lighting device according to claim 2;
Detecting means for detecting a rotational position of a butting portion formed between the plurality of phosphor pieces adjacent to each other;
An image display element for generating image light by modulating light emitted from the illumination device with an image signal;
A projection lens for enlarging and projecting the image light generated by the image display element,
The lighting device has a plurality of the spreaders,
Based on the rotational position of the butting portion detected by the detecting means, the timing at which the excitation light reaches the butting portion of the phosphor is controlled so as to be different in each of a plurality of spreaders. Video display device.

Images