JP7700670B2 - Display device and display method - Google Patents

Description

The present invention relates to a display device and a display method.

As a display device for stereoscopic images, a configuration has been proposed in which quantum dot blocks are combined three-dimensionally and ultraviolet light is irradiated from two directions (see, for example, Patent Document 1).

JP 2015-165611 A

The above-mentioned prior art does not mention controlling the irradiation position of the ultraviolet light irradiated onto the quantum dot block. If the irradiation position is shifted, the intended three-dimensional image cannot be displayed with high accuracy.

The present invention was made in consideration of the above circumstances, and aims to provide a technology that improves the display accuracy of stereoscopic images.

A display device according to one embodiment of the present invention includes a display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are laminated, an irradiation unit that irradiates the display body with excitation light that is incident on the display body and excites the first phosphor and the second phosphor by changing the focusing position of the excitation light within the display body, an optical sensor that measures the light intensity for each wavelength of light emitted from the display body, and a control unit that controls the focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor.

Another aspect of the present invention is a display method. This method includes the steps of irradiating an excitation light incident on a display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are stacked, and exciting the first phosphor and the second phosphor, while changing the focusing position of the excitation light within the display body, measuring the intensity of the light by wavelength emitted from the display body with an optical sensor, and controlling the focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor.

In addition, any combination of the above components or mutual substitution of the components or expressions of the present invention between methods, devices, systems, etc. are also valid aspects of the present invention.

The present invention can improve the display accuracy of stereoscopic images.

1 is a diagram illustrating a schematic configuration of a display device according to a first embodiment. 13 is a graph illustrating an example of a light intensity distribution of a second excitation light. 1 is a graph showing a schematic relationship between excitation light intensity and emission intensity of a phosphor. FIG. 11 is a diagram illustrating a schematic configuration of a display device according to a second embodiment. FIG. 13 is a diagram illustrating a configuration of a display device according to a third embodiment. FIG. 13 is a diagram illustrating a configuration of a display according to a fourth embodiment. FIG. 13 is a diagram illustrating a configuration of an optical sensor according to a fourth embodiment. FIG. 13 is a diagram illustrating a configuration of a display device according to a fifth embodiment. FIG. 13 is a diagram illustrating a configuration of a display device according to a sixth embodiment.

The following describes an embodiment of the present invention with reference to the drawings. The specific numerical values and the like shown in the embodiment are merely examples to facilitate understanding of the invention, and do not limit the present invention unless otherwise specified. In the drawings, elements that are not directly related to the present invention are omitted. To facilitate understanding of the description, the dimensional ratios of the components in each drawing do not necessarily match the actual dimensional ratios.

First Embodiment
1 is a diagram illustrating a schematic configuration of a display device 10 according to a first embodiment. The display device 10 includes a display body 12, a first irradiating unit 14, a second irradiating unit 16, and a control unit 18. The display device 10 is a so-called volume display, and is configured to render a three-dimensional image S inside the display body 12.

The display body 12 has a first surface 26 and a second surface 28, and includes a plurality of laminates 30 laminated in the z direction from the first surface 26 to the second surface 28. Each of the plurality of laminates 30 has a first fluorescent layer 31, a second fluorescent layer 32, and a third fluorescent layer 33. The display body 12 has a structure in which a plurality of fluorescent layers are laminated in order, such as the first fluorescent layer 31, the second fluorescent layer 32, the third fluorescent layer 33, the first fluorescent layer 31, the second fluorescent layer 32, the third fluorescent layer 33, ... For example, the plurality of second fluorescent layers 32 are alternately arranged with the plurality of first fluorescent layers 31, and the plurality of third fluorescent layers 33 are alternately arranged with the plurality of first fluorescent layers 31 and the plurality of second fluorescent layers 32.

The first fluorescent layer 31 is a fluorescent layer containing a first phosphor having an emission wavelength in the visible range, and for example, contains a first phosphor having an emission color of red (R). The second fluorescent layer 32 is a fluorescent layer containing a second phosphor having an emission wavelength in the visible range different from that of the first phosphor, and for example, contains a second phosphor having an emission color of green (G). The third fluorescent layer 33 is a fluorescent layer containing a third phosphor having an emission wavelength in the visible range different from that of the first phosphor and the second phosphor, and for example, contains a third phosphor having an emission color of blue (B).

The materials of the first phosphor, the second phosphor, and the third phosphor are not particularly limited, but for example, quantum dot phosphors can be used. By using quantum dot phosphors, the excitation wavelengths of the first phosphor, the second phosphor, and the third phosphor can be made common, and the emission wavelengths (i.e., emission colors) of the first phosphor, the second phosphor, and the third phosphor can be made different. As an example of a phosphor, nanocrystalline particles of cesium lead halide perovskite (CsPbX ₃ , X is a halogen, and either Cl, Br, or I, or a mixture of these) can be used, and the excitation wavelength is set to ultraviolet light of 300 nm to 400 nm, and RGB emission wavelengths can be obtained.

The base material of the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 is made of a material that is transparent to visible light, such as a resin material or a glass material. By mixing a phosphor into the transparent base material, the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 can be formed, and the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 can be stacked in order to form the display body 12.

The display body 12 is configured so that the entire body has a solid columnar shape, and is configured so that the shape is a cylinder, a polygonal column, or a rectangular parallelepiped. The display body 12 is configured so that the surface of the display body 12 has a mirror finish so that the inside of the display body 12 can be seen from the outside. The display body 12 is formed so that the multiple fluorescent layers 31, 32, and 33 are integrated together so that the interfaces between the multiple fluorescent layers 31, 32, and 33 are invisible or difficult to see.

The size of the display body 12 is not particularly limited, but for example, the size in the stacking direction (z direction) can be about 100 mm to 1000 mm, and the size in the directions perpendicular to the stacking direction (x direction and y direction) can be about 100 mm to 1000 mm. The thickness of each of the multiple fluorescent layers 31, 32, 33 can be, for example, about 10 μm to 10 mm. As an example, the size of the display body 12 in the x, y, and z directions can be 200 mm, and the thickness of each of the multiple fluorescent layers 31, 32, 33 can be 200 μm.

The first irradiation unit 14 irradiates the display body 12 with first excitation light 20 that excites the phosphor. The first excitation light 20 is incident on the first surface 26 of the display body 12, and is irradiated onto the display body 12 such that the focusing position 24 of the first excitation light 20 changes over time inside the display body 12. The first irradiation unit 14 includes a light source 40, a focusing lens 42, a lens driving mechanism 44, a mirror 46, and a mirror driving mechanism 48.

The light source 40 generates the first excitation light 20 for exciting the first phosphor, the second phosphor, and the third phosphor. The light source 40 generates ultraviolet light having a central wavelength in the range of 300 nm to 400 nm as the first excitation light 20. Any type of light source 40 can be used, but for example, a gallium nitride (GaN)-based semiconductor laser or a semiconductor LED (Light Emitting Diode) can be used as the light source 40.

The focusing lens 42 focuses the first excitation light 20 generated by the light source 40 toward the inside of the display body 12. The lens driving mechanism 44 is configured to change the position of the focusing lens 42 in the optical axis direction A. The lens driving mechanism 44 changes the focusing position 24 of the first excitation light 20 by changing the position of the focusing lens 42. The lens driving mechanism 44 makes the focusing position 24 in the irradiation direction of the first excitation light 20 variable, and makes the focusing position 24 in the direction intersecting the first surface 26 variable. Note that a variable focus lens may be used instead of the focusing lens 42 and the lens driving mechanism 44 to make the focusing position 24 in the direction intersecting the first surface 26 variable.

The mirror 46 reflects the first excitation light 20 that has passed through the focusing lens 42 toward the display 12. The mirror 46 reflects the first excitation light 20 so that the first excitation light 20 is incident on the first surface 26. The mirror drive mechanism 48 is configured to change the orientation of the mirror 46. The mirror drive mechanism 48 is configured to change the orientation of the mirror 46 on two axes, and changes the focusing position 24 of the first excitation light 20 reflected by the mirror 46 in the directions along the first surface 26 (x direction and y direction). In the illustrated example, one mirror 46 is used, but a first mirror for scanning in the x direction and a second mirror for scanning in the y direction may be combined.

The second irradiating unit 16 irradiates the display body 12 with second excitation light 22 for exciting the phosphor. The second excitation light 22 is incident on the second surface 28 of the display body 12 and is irradiated to the display body 12 from the side opposite to the first excitation light 20. The second irradiating unit 16 is a surface-emitting light source configured to irradiate the second excitation light 22 to the entire second surface 28 of the display body 12. The second excitation light 22 may have the same wavelength as the first excitation light 20, or may be ultraviolet light with a central wavelength in the range of 300 nm to 400 nm.

The second excitation light 22 has a role of assisting the excitation of the phosphor by the first excitation light 20. The intensity of the first excitation light 20 incident on the first surface 26 of the display body 12 attenuates as it passes through the display body 12. In addition, when the focusing position 24 of the first excitation light 20 is changed by the position of one focusing lens 42 as shown in FIG. 1, the spot diameter of the first excitation light 20 becomes larger as the focusing position 24 approaches the second surface 28, and the focusing intensity of the first excitation light 20 becomes smaller. Therefore, when the output intensity of the light source 40 is constant, the focusing intensity of the first excitation light 20 becomes stronger as the focusing position 24 is closer to the first surface 26, and becomes weaker as the focusing position 24 is closer to the second surface 28. On the other hand, the light intensity of the second excitation light 22 becomes stronger as it is closer to the second surface 28, and becomes weaker as it is closer to the first surface 26. By irradiating the display 12 with such second excitation light 22, excitation at the focusing position 24 is assisted, and the variation in the total light intensity of the first excitation light 20 and the second excitation light 22 at the focusing position 24 caused by changes in the position of the focusing position 24 can be reduced.

2 is a graph showing an example of the light intensity distribution of the second excitation light 22. The second irradiation unit 16 may irradiate the second excitation light 22 having a uniform light intensity on the second surface 28, as shown by the solid line C in FIG. 2. The second irradiation unit 16 may irradiate the second excitation light 22 having an intensity distribution according to the position on the second surface 28. The second irradiation unit 16 may irradiate the second excitation light 22 having an intensity distribution in which the light intensity is relatively low in the center of the second surface 28 and relatively high in the peripheral portion of the second surface 28, as shown by the dashed line D in FIG. 2. The central portion of the display body 12 is relatively short from the mirror 46 that reflects the first excitation light 20, so the collected light intensity of the first excitation light 20 is larger than that of the peripheral portion that is far from the mirror 46. On the other hand, the peripheral portion of the display body 12 is relatively long from the mirror 46, so the collected light intensity of the first excitation light 20 is relatively small. Therefore, by lowering the light intensity in the center of the second excitation light 22 and increasing the light intensity in the peripheral portion of the second excitation light 22, it is possible to reduce the variation in the total light intensity of the first excitation light 20 and the second excitation light 22 at the focusing position 24 caused by the change in the position of the focusing position 24.

The light intensity of the second excitation light 22 is set so as not to exceed the threshold of the amplified spontaneous emission (ASE) of the phosphor contained in the display 12. On the other hand, the sum of the light intensities of the first excitation light 20 and the second excitation light 22 at the focusing position 24 is set so as to be equal to or greater than the threshold of the amplified spontaneous emission (ASE threshold). The amplified spontaneous emission (ASE) is also called superluminescence, and refers to a phenomenon in which a population inversion is generated in the phosphor by the excitation light, amplifying the luminescence intensity of the phosphor. The threshold of the amplified spontaneous emission (ASE threshold) corresponds to the minimum light intensity of the excitation light required to generate ASE.

3 is a graph showing a schematic relationship between the excitation light intensity and the emission intensity of a phosphor, and shows an example in which the phosphor is a nanocrystal of cesium lead halide perovskite. When the light intensity of the excitation light irradiated to the phosphor is equal to or greater than the ASE threshold (0.45 mJ/cm ² in FIG. 3), the ratio (slope) of the emission intensity to the excitation light intensity increases. By making the excitation light intensity at the focusing position 24 equal to or greater than the ASE threshold, the emission intensity of the phosphor at the focusing position 24 can be further increased. On the other hand, by making the excitation light intensity at a position other than the focusing position 24 less than the ASE threshold, the emission intensity of the phosphor at a position other than the focusing position 24 can be reduced, and the contrast ratio with the focusing position 24 can be increased.

Returning to FIG. 1, the control unit 18 controls the operation of the first irradiation unit 14 and the second irradiation unit 16. In terms of hardware, the control unit 18 can be realized by elements and mechanical devices such as a computer's CPU and memory, and in terms of software, it is realized by a computer program, etc. The various functions provided by the control unit 18 can be realized by the cooperation of hardware and software.

The control unit 18 controls the focusing position 24 of the first excitation light 20 in three dimensions (x direction, y direction, and z direction) by controlling the operation of the lens driving mechanism 44 and the mirror driving mechanism 48. The control unit 18, for example, periodically operates the lens driving mechanism 44 and the mirror driving mechanism 48 so that the focusing position 24 of the first excitation light 20 is scanned three-dimensionally inside the display body 12.

The control unit 18 controls the on/off of the light source 40 according to, for example, the focusing position 24 of the first excitation light 20. The control unit 18 turns on the light source when the focusing position 24 of the first excitation light 20 is a location inside the display body 12 where drawing should be performed. The control unit 18 turns off the light source when the focusing position 24 of the first excitation light 20 is a location inside the display body 12 where drawing should not be performed.

The control unit 18 controls the on/off of the light source 40 and the light emission intensity of the light source 40 based on, for example, three-dimensional contour image data generated from three-dimensional image data. The three-dimensional contour image data is data that specifies the three-dimensional position and display color of the contour of the three-dimensional image S to be drawn on the display body 12. The control unit 18 controls the display color by controlling the light intensity of the first excitation light 20 that is irradiated to each of the adjacent first fluorescent layer 31, second fluorescent layer 32, and third fluorescent layer 33. Specifically, by controlling the amount of red light emitted from the first fluorescent layer 31, the amount of green light emitted from the second fluorescent layer 32, and the amount of blue light emitted from the third fluorescent layer 33, the light emission color resulting from the mixture of red, green, and blue at the light emission position is controlled in full color.

The control unit 18 may change the light intensity of the second excitation light 22 according to the focusing position 24 of the first excitation light 20 by controlling the operation of the second irradiation unit 16. For example, the light intensity of the second excitation light 22 may be increased as the focusing position 24 of the first excitation light 20 is closer to the second surface 28, that is, as it is farther from the first surface 26. This may allow the sum of the light intensities of the first excitation light 20 and the second excitation light 22 at the focusing position 24 to be equal to or greater than the ASE threshold.

The display device 10 may further include an image sensor 50. The image sensor 50 is a two-dimensional photodetector such as a CCD sensor or a CMOS sensor, and is provided to measure the spot size of the first excitation light 20. The image sensor 50 is disposed adjacent to the display body 12 at a position corresponding to the first surface 26. The image sensor 50 may be provided at a position different from that shown in the figure, as long as the first excitation light 20 can be incident on the image sensor 50.

The control unit 18 operates the lens driving mechanism 44 and the mirror driving mechanism 48 so that the first excitation light 20 is incident on the image sensor 50. The control unit 18 measures the size of the first excitation light 20 on the image sensor 50 while changing the position of the focusing lens 42, thereby identifying the position of the focusing lens 42 at which the spot size of the first excitation light 20 is smallest. The identified position of the focusing lens 42 can be used as a reference for positioning in the z direction to match the focusing position 24 of the first excitation light 20 with the first surface 26. The control unit 18 can calibrate the focusing position 24 of the first excitation light 20 based on the measurement result of the image sensor 50.

Next, the operation of the display device 10 will be described. The control unit 18 acquires the three-dimensional contour image data and operates the first irradiation unit 14 based on the three-dimensional contour image data. The control unit 18 controls the operation of the lens driving mechanism 44 and the mirror driving mechanism 48 to perform three-dimensional scanning of the focusing position 24 of the first excitation light 20 inside the display body 12. The control unit 18 controls the output intensity of the light source 40 according to the focusing position 24 of the first excitation light 20 so that the display color specified for each drawing position by the three-dimensional contour image data is realized. The control unit 18 operates the second irradiation unit 16 to irradiate the display body 12 with the second excitation light 22 to supplement the excitation by the first excitation light 20. This allows a three-dimensional image S corresponding to the three-dimensional contour image data to be drawn inside the display body 12.

The control unit 18 may obtain three-dimensional contour image data corresponding to each frame of the video data, and may render a different three-dimensional image S for each frame. This may allow the three-dimensional image S to be displayed as a video.

The control unit 18 may calibrate the focusing position 24 of the first excitation light 20 based on the measurement results of the image sensor 50. The control unit 18 may calibrate the focusing position 24 before starting to draw the three-dimensional image S based on the measurement results of the image sensor 50. The control unit 18 may calibrate the focusing position 24 during drawing of the three-dimensional image S or at the timing between drawing each frame of the three-dimensional image S that becomes a video based on the measurement results of the image sensor 50.

According to this embodiment, by setting the light intensity of the second excitation light 22 below the ASE threshold, it is possible to prevent the entire display 12 from emitting bright light. On the other hand, by setting the sum of the light intensities of the first excitation light 20 and the second excitation light 22 at the focusing position 24 to be equal to or greater than the ASE threshold, it is possible to obtain strong ASE emission at the focusing position 24, and to increase the contrast ratio with the emission (background light) at a location other than the focusing position 24.

Second Embodiment
4 is a diagram showing a schematic configuration of a display device 10A according to a second embodiment. The second embodiment differs from the first embodiment in that the first irradiation unit 14A further includes a collimator lens 41. Hereinafter, the second embodiment will be described with a focus on the differences from the first embodiment, and the points in common with the first embodiment will be omitted as appropriate.

The display device 10A includes a display body 12, a first irradiation unit 14A, a second irradiation unit 16, and a control unit 18. The display body 12, the second irradiation unit 16, and the control unit 18 are configured in the same manner as in the first embodiment.

The first irradiation unit 14A includes a light source 40, a collimator lens 41, a condenser lens 42, a lens driving mechanism 44, a mirror 46, and a mirror driving mechanism 48. The light source 40, the condenser lens 42, the lens driving mechanism 44, the mirror 46, and the mirror driving mechanism 48 are configured in the same manner as in the first embodiment.

The collimating lens 41 collimates the first excitation light 20 generated by the light source 40. The focusing lens 42 focuses the first excitation light 20 collimated by the collimating lens 41 toward the inside of the display body 12. The lens driving mechanism 44 changes the position of the focusing lens 42 to change the focusing position 24 of the first excitation light 20.

According to this embodiment, by using the collimator lens 41, it is possible to suppress the change in the spot diameter of the first excitation light 20 according to the focusing position 24 of the first excitation light 20. This makes it possible to reduce the fluctuation in the light intensity of the first excitation light 20 at the focusing position 24 caused by the change in the focusing position 24. As a result, compared to the first embodiment, the proportion of assistance by the second excitation light 22 can be reduced, and the proportion of the change in the light intensity of the second excitation light 22 according to the focusing position 24 can be reduced. By reducing the proportion of assistance by the second excitation light 22, it is possible to reduce the intensity of the emission (background light) at a location other than the focusing position 24. In addition, by reducing the proportion of the change in the light intensity of the second excitation light 22 according to the focusing position 24, it is possible to reduce the variation in the intensity of the emission (background light) at a location other than the focusing position 24.

Third Embodiment
5 is a diagram illustrating a schematic configuration of a display device 10B according to a third embodiment. The third embodiment differs from the first embodiment in that the display device 10B further includes a light sensor 52. Hereinafter, the third embodiment will be described with a focus on the differences from the first embodiment, and the points in common with the first embodiment will be omitted as appropriate.

The display device 10B includes a display body 12, a first irradiation unit 14, a control unit 18, and an optical sensor 52. The display device 10B may or may not include a second irradiation unit 16. The display device 10B may or may not include an image sensor 50. The display body 12, the first irradiation unit 14, the second irradiation unit 16, the control unit 18, and the image sensor 50 are configured in the same manner as in the first embodiment.

The optical sensor 52 is configured to be able to measure the light intensity for each wavelength. The optical sensor 52 is configured to be able to measure, for example, the light intensity of the first emission color (e.g., red) of the first phosphor, the light intensity of the second emission color (e.g., green) of the second phosphor, and the light intensity of the third emission color (e.g., blue) of the third phosphor. The optical sensor 52 includes, for example, a first sensor 54 having a first filter that selectively transmits red light, a second sensor 56 having a second filter that selectively transmits green light, and a third sensor 58 having a third filter that selectively transmits blue light. The optical sensor 52 is disposed, for example, on the second surface 28 of the display body 12. The optical sensor 52 may be disposed at a position different from the position shown in the figure, as long as the position is capable of detecting the emission generated by the display body 12.

The control unit 18 operates the lens drive mechanism 44 to change the position of the focusing lens 42, while acquiring the light intensity of each of the first emission color, the second emission color, and the third emission color measured by the optical sensor 52. By changing the focusing position 24 of the first excitation light 20, the first excitation light 20 is strongly focused on the first fluorescent layer 31, the second fluorescent layer 32, or the third fluorescent layer 33, which changes the light intensity of each of the first emission color, the second emission color, and the third emission color. For example, the position of the focusing lens 42 at which the light intensity of the first emission color measured by the optical sensor 52 is maximum (or maximum) can be used as a reference for positioning in the z direction to match the focusing position 24 of the first excitation light 20 with the first fluorescent layer 31.

The control unit 18 can calibrate the focusing position 24 of the first excitation light 20 based on the measurement result of the optical sensor 52. The control unit 18 may calibrate the focusing position 24 before starting to draw the stereoscopic image S based on the measurement result of the optical sensor 52. The control unit 18 may calibrate the focusing position 24 during drawing of the stereoscopic image S or at the timing between drawing each frame of the stereoscopic image S that becomes a video based on the measurement result of the optical sensor 52. According to this embodiment, by calibrating the focusing position 24 of the first excitation light 20 based on the measurement result of the optical sensor 52, the positional accuracy of drawing the stereoscopic image S can be improved, and the display accuracy of the stereoscopic image S can be improved.

Fourth Embodiment
In the fourth embodiment, a part of the fluorescent layer included in the display contains an infrared phosphor having an emission wavelength in the infrared range. The infrared phosphor is excited by the first excitation light 20 to emit infrared light. The light intensity of the infrared light generated from the infrared phosphor is detected by an optical sensor and used to determine in which fluorescent layer the focusing position 24 of the first excitation light 20 is located.

As the infrared phosphor, multiple types of infrared phosphors having different emission wavelengths in the infrared range can be used. For example, a first infrared phosphor having an emission wavelength of 800 nm, a second infrared phosphor having an emission wavelength of 900 nm, a third infrared phosphor having an emission wavelength of 1000 nm, a fourth infrared phosphor having an emission wavelength of 1100 nm, a fifth infrared phosphor having an emission wavelength of 1200 nm, and a sixth infrared phosphor having an emission wavelength of 1300 nm can be used. By varying the type of infrared phosphor contained in the fluorescent layer, it is possible to determine in which fluorescent layer the focusing position 24 of the first excitation light 20 is located, based on the wavelength of the infrared light detected by the optical sensor.

The following describes the fourth embodiment, focusing on the differences from the above-mentioned third embodiment, and omitting commonalities with the third embodiment as appropriate. The display device according to the fourth embodiment has a similar configuration to the display device 10 according to the third embodiment, but the configurations of the display body 12 and the optical sensor 52 are different.

Figure 6 is a diagram showing a schematic configuration of a display body 12C according to the fourth embodiment. The display body 12C includes a plurality of laminates 30a, 30b, 30c, 30d, 30e, 30f, 30g, 30h, 30i, and 30j that are laminated in the z direction.

The laminates 30a to 30f each have a first fluorescent layer 31a to 31f containing a first phosphor and an infrared phosphor, a second fluorescent layer 32 containing a second phosphor and not containing an infrared phosphor, and a third fluorescent layer 33 containing a third phosphor and not containing an infrared phosphor. The first fluorescent layer 31a contained in the first laminate 30a contains a first phosphor and a first infrared phosphor (e.g., having an emission wavelength of 800 nm). The first fluorescent layer 31b contained in the second laminate 30b contains a first phosphor and a second infrared phosphor (e.g., having an emission wavelength of 900 nm). The first fluorescent layer 31c contained in the third laminate 30c contains a first phosphor and a third infrared phosphor (e.g., having an emission wavelength of 1000 nm). The first fluorescent layer 31d included in the fourth stack 30d contains a first phosphor and a fourth infrared phosphor (e.g., having an emission wavelength of 1100 nm). The first fluorescent layer 31e included in the fifth stack 30e contains a first phosphor and a fifth infrared phosphor (e.g., having an emission wavelength of 1200 nm). The first fluorescent layer 31f included in the sixth stack 30f contains a first phosphor and a sixth infrared phosphor (e.g., having an emission wavelength of 1300 nm).

The laminates 30g and 30h have a first fluorescent layer 31 that contains a first phosphor but does not contain an infrared phosphor, a second fluorescent layer 32a, 32b that contains a second phosphor and an infrared phosphor, and a third fluorescent layer 33 that contains a third phosphor but does not contain an infrared phosphor. The second fluorescent layer 32a included in the seventh laminate 30g contains a second phosphor and a first infrared phosphor (e.g., having an emission wavelength of 800 nm). The second fluorescent layer 32b included in the eighth laminate 30h contains a second phosphor and a second infrared phosphor (e.g., having an emission wavelength of 900 nm). The second fluorescent layer included in the laminate not shown in the figure may contain the second phosphor and any one of the third infrared phosphor, the fourth infrared phosphor, the fifth infrared phosphor, and the sixth infrared phosphor.

The laminates 30i and 30j have a first fluorescent layer 31 that contains a first phosphor but does not contain an infrared phosphor, a second fluorescent layer 32 that contains a second phosphor but does not contain an infrared phosphor, and third fluorescent layers 33a and 33b that contain a third phosphor and an infrared phosphor. The third fluorescent layer 33a included in the ninth laminate 30i contains a third phosphor and a first infrared phosphor (e.g., having an emission wavelength of 800 nm). The third fluorescent layer 33b included in the tenth laminate 30j contains a third phosphor and a second infrared phosphor (e.g., having an emission wavelength of 900 nm). The third fluorescent layer included in a laminate not shown in the figure may contain the third phosphor and any one of the third infrared phosphor, the fourth infrared phosphor, the fifth infrared phosphor, and the sixth infrared phosphor.

Figure 7 is a schematic diagram showing the configuration of an optical sensor 52C according to the fourth embodiment. The optical sensor 52C has multiple sensors 54, 56, 58, 60a, 60b, 60c, 60d, 60e, and 60f that can detect different wavelengths. The first sensor 54, the second sensor 56, and the third sensor 58 are configured in the same manner as in the third embodiment, and are configured to measure the light intensity of red, green, and blue, for example.

The optical sensor 52C has a plurality of infrared sensors 60a to 60f. The first infrared sensor 60a is configured to measure the light intensity of the emission wavelength of the first infrared phosphor, and has a filter that selectively transmits, for example, 800 nm infrared light. The second infrared sensor 60b is configured to measure the light intensity of the emission wavelength of the second infrared phosphor, and has a filter that selectively transmits, for example, 900 nm infrared light. The third infrared sensor 60c is configured to measure the light intensity of the emission wavelength of the third infrared phosphor, and has a filter that selectively transmits, for example, 1000 nm infrared light. The fourth infrared sensor 60d is configured to measure the light intensity of the emission wavelength of the fourth infrared phosphor, and has a filter that selectively transmits, for example, 1100 nm infrared light. The fifth infrared sensor 60e is configured to measure the light intensity of the emission wavelength of the fifth infrared phosphor, and has a filter that selectively transmits, for example, 1200 nm infrared light. The sixth infrared sensor 60f is configured to measure the light intensity of the emission wavelength of the sixth infrared phosphor, and has a filter that selectively transmits, for example, infrared light of 1300 nm.

The control unit 18 operates the lens drive mechanism 44 to change the position of the focusing lens 42, while acquiring the light intensity for each wavelength measured by the optical sensor 52C. Based on the light intensity for each wavelength measured by the optical sensor 52C, the control unit 18 determines in which of the multiple types of infrared phosphors the focusing position 24 of the first excitation light 20 is located. For example, when the light intensity of the emission wavelength (red) of the first phosphor is maximum (or maximal) and the light intensity of the emission wavelength (800 nm) of the first infrared phosphor is maximum (or maximal), it can be determined that the focusing position 24 is located in the first fluorescent layer 31a containing the first phosphor and the first infrared phosphor.

In the example of FIG. 6, the case where each of the successive laminates 30a to 30h contains an infrared phosphor is shown. In a modified example, laminates containing an infrared phosphor and laminates not containing an infrared phosphor may be alternately laminated. For example, a plurality of (e.g., nine) laminates 30 not containing an infrared phosphor may be laminated on a first laminate 30a containing a first infrared phosphor, and a second laminate 30b containing a second infrared phosphor may be laminated on top of the first laminate. For example, a fluorescent layer containing an infrared phosphor as a reference for positioning may be provided for every ten laminates. This allows the reference for positioning to be set with appropriate intervals when the display body 12C has a large number of laminates 30.

In the example of FIG. 6, one fluorescent layer contains one type of infrared phosphor. In a further modified example, one fluorescent layer may contain two or more types of infrared phosphor. For example, one fluorescent layer may contain a first infrared phosphor and a second infrared phosphor, or a first infrared phosphor, a second infrared phosphor, and a third infrared phosphor. In addition, the combination of infrared phosphors contained may be different depending on the fluorescent layer that serves as the reference for positioning. By combining two or more types of infrared phosphors, the number of patterns for identifying the fluorescent layer can be increased using a limited number of types of infrared phosphors. As a result, when the number of layers of the laminate 30 of the display body 12C is large, the position of the fluorescent layer can be grasped more precisely, and the display accuracy of the three-dimensional image S can be improved.

Fifth Embodiment
8 is a diagram showing a schematic configuration of a display device 10D according to a fifth embodiment. The fifth embodiment differs from the first embodiment in that a power source 70 that applies a voltage between the first surface 26 and the second surface 28 of the display body 12 is provided instead of the second irradiation unit 16. Hereinafter, the fifth embodiment will be described with a focus on the differences from the first embodiment, and the points in common with the first embodiment will be omitted as appropriate.

The display device 10D includes a display 12D, a first irradiation unit 14, a control unit 18, a first electrode 66, a second electrode 68, and a power source 70. The first irradiation unit 14 and the control unit 18 are configured in the same manner as in the first embodiment.

The display body 12D is configured in the same manner as the display body 12 according to the first embodiment, but differs from the first embodiment in that it has electrical conductivity. Each of the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 included in the multiple laminates 30 of the display body 12D is configured to have electrical conductivity. For example, the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 can be configured to have electrical conductivity by using a conductive polymer such as polyacetylene or polythiophene as the base material. In addition, the first fluorescent layer 31, the second fluorescent layer 32, and the third fluorescent layer 33 may be made electrically conductive by containing conductive particles.

The first electrode 66 is provided on the first surface 26 of the display body 12D. The first electrode 66 is a transparent electrode that transmits the first excitation light 20, and is made of a conductive oxide material such as indium tin oxide (ITO). The second electrode 68 is provided on the second surface 28 of the display body 12D. The second electrode 68 is preferably a transparent electrode like the first electrode 66, but does not have to be a transparent electrode.

The power supply 70 applies a voltage between the first electrode 66 and the second electrode 68. The power supply 70 electrically excites the phosphor contained in the display body 12D by applying a voltage to the display body 12D. The power supply 70 applies an auxiliary voltage to the entire display body 12D to auxiliary excite the phosphor contained in the display body 12D. When electrically exciting the phosphor, the amount of light emitted by the phosphor depends on the current density, and the amount of light emitted increases as the current density increases. The power supply 70 controls the current flowing between the first electrode 66 and the second electrode 68 so that the current density is such that the phosphor does not generate ASE when the first excitation light 20 is not irradiated. In other words, the current density flowing between the first electrode 66 and the second electrode 68 is controlled to be less than the "threshold current density of amplified spontaneous emission light," which is the current density required to generate ASE. The power supply 70 may have a constant current circuit.

When an auxiliary voltage is applied by the power supply 70, the first irradiation unit 14 irradiates the first excitation light 20 having a light intensity that enables the phosphor to generate ASE at the focusing position 24 of the first excitation light 20. The first irradiation unit 14 causes the phosphor to generate ASE at the focusing position 24 by the sum of the contribution of the first excitation light 20 at the focusing position 24 and the contribution of the electrical excitation by the power supply 70.

The control unit 18 may change the current density of the current flowing through the display body 12D according to the focusing position 24 of the first excitation light 20 by controlling the operation of the power supply 70. For example, the amount of current (or current density) flowing through the display body 12D may be increased as the focusing position 24 of the first excitation light 20 is closer to the second surface 28, that is, as it is farther from the first surface 26. This may cause the phosphor to generate ASE at the focusing position 24 while suppressing the variation in the total contribution of the first excitation light 20 at the focusing position 24 and the contribution of the electrical excitation by the power supply 70.

Sixth Embodiment
9 is a diagram showing a schematic configuration of a display device 10E according to a sixth embodiment. The sixth embodiment differs from the fifth embodiment in that separate power sources 70a and 70b are connected to the center and peripheral portions of a display body 12D. Hereinafter, the sixth embodiment will be described with a focus on the differences from the fifth embodiment, and the points in common with the fifth embodiment will be omitted as appropriate.

The display device 10E includes a display body 12D, a first irradiation unit 14, a control unit 18, a first electrode 66, a second electrode 68, and a power source 70. The display body 12D, the first irradiation unit 14, and the control unit 18 are configured in the same manner as in the fifth embodiment.

The second electrode 68 has a central electrode 68a provided in the center of the second surface 28 of the display body 12, and a peripheral electrode 68b provided in the peripheral portion of the second surface 28. The power supply 70 has a first power supply 70a connected between the first electrode 66 and the central electrode 68a, and a second power supply 70b connected between the first electrode 66 and the peripheral electrode 68b.

The first power source 70a is configured to pass a current of a first current density through the center of the display body 12D. The second power source 70b is configured to pass a current of a second current density, which is greater than the first current density, through the peripheral portion of the display body 12D. The peripheral portion of the display body 12D is relatively far from the mirror 46, and therefore the focusing intensity of the first excitation light 20 is relatively small compared to the central portion of the display body 12D. Therefore, by making the current density of the central portion of the display body 12D relatively low and the current density of the peripheral portion of the display body 12D relatively high, the variation in the total contribution of the first excitation light 20 and the electrical excitation at the focusing position 24 due to the change in the position of the focusing position 24 can be reduced.

The example in FIG. 9 shows a case where two electrodes 68a, 68b are provided on the second surface 28. In a further modified example, three or more electrodes may be provided concentrically on the second surface 28, and each of the three or more electrodes may be connected to a separate power source. In this case, a voltage may be applied so that the current density is smaller in the center of the display body 12D and larger in the peripheral portion of the display body 12D.

The present invention has been described above with reference to the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, and appropriate combinations or substitutions of the configurations shown in each display example are also included in the present invention.

In the third and fourth embodiments, the second irradiation unit 16 may not be used, and the power supply 70 for applying the auxiliary voltage in the fifth or sixth embodiment may be used instead of the second irradiation unit 16. In addition, in the third to sixth embodiments, the first irradiation unit 14A including the collimator lens 41 in the second embodiment may be used.

Several aspects of the invention are described below.

[Aspect 1]
A display body in which a plurality of fluorescent layers containing a phosphor are laminated from a first surface to a second surface;
a first irradiating unit that irradiates first excitation light, which is incident on the first surface and excites the phosphor, while changing a focusing position of the first excitation light within the display;
a second irradiating unit that irradiates second excitation light that is incident on the second surface and excites the phosphor,
the light intensity of the second excitation light is less than a threshold of the amplified spontaneous emission light of the phosphor;
A display device, wherein a sum of the light intensities of the first excitation light and the second excitation light is equal to or greater than a threshold value of amplified spontaneous emission light of the phosphor.
[Aspect 2]
The display device according to aspect 1, wherein the second irradiator changes a light intensity of the second excitation light in accordance with the focused position of the first excitation light.
[Aspect 3]
The display device according to aspect 1 or 2, wherein the second irradiating section irradiates the second excitation light onto the entire second surface.
[Aspect 4]
The display device according to aspect 3, wherein the second irradiating section irradiates the second excitation light having an intensity distribution in which a light intensity is higher in a peripheral portion of the second surface than in a central portion of the second surface.
[Aspect 5]
a step of irradiating a first excitation light, which is incident on a first surface of a display body in which a plurality of fluorescent layers containing a phosphor are laminated from a first surface to a second surface and excites the phosphor, while changing a focusing position of the first excitation light within the display body;
and irradiating the second surface with second excitation light that is incident on the second surface and excites the phosphor.
the light intensity of the second excitation light is less than a threshold of the amplified spontaneous emission light of the phosphor;
A display method, wherein a sum of the light intensities of the first excitation light and the second excitation light is equal to or greater than a threshold value of amplified spontaneous emission light of the phosphor.

[Aspect 6]
A display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are laminated;
an irradiation unit that irradiates the display body with excitation light that is incident on the display body and excites the first phosphor and the second phosphor while changing a focusing position of the excitation light within the display body;
an optical sensor that measures the light intensity of light emitted from the display body for each wavelength;
a control unit that controls the focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor.
[Aspect 7]
The display includes a fluorescent layer containing an infrared phosphor having an emission wavelength in the infrared range,
7. The display device according to aspect 6, wherein the control unit controls a focusing position of the excitation light further based on a light intensity of an emission wavelength of the infrared phosphor measured by the optical sensor.
[Aspect 8]
The display includes a fluorescent layer containing a first infrared phosphor having an emission wavelength in an infrared range, and a fluorescent layer containing a second infrared phosphor having an emission wavelength in an infrared range different from that of the first infrared phosphor,
The display device of aspect 7, wherein the control unit controls the focusing position of the excitation light further based on the light intensity of the emission wavelength of the first infrared phosphor and the light intensity of the emission wavelength of the second infrared phosphor measured by the optical sensor.
[Aspect 9]
The display includes a fluorescent layer containing two or more of a plurality of types of infrared phosphors having different emission wavelengths in the infrared range,
10. The display device according to aspect 8 or 9, wherein the control unit controls a focusing position of the excitation light further based on the light intensity of each of the emission wavelengths of the plurality of types of infrared phosphors measured by the optical sensor.
[Aspect 10]
a step of irradiating an excitation light incident on a display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are laminated, the excitation light exciting the first phosphor and the second phosphor, while changing a focusing position of the excitation light in the display body;
measuring the intensity of light emitted from the display by wavelength using an optical sensor;
and controlling a focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor.

[Aspect 11]
A display body in which a plurality of fluorescent layers containing a phosphor are laminated from a first surface to a second surface;
A first electrode provided on the first surface;
a second electrode provided on the second surface;
a power source that applies a voltage between the first electrode and the second electrode;
an irradiation unit that irradiates the display body with excitation light that is incident on the display body and excites the phosphor, while changing a focusing position of the excitation light within the display body.
[Aspect 12]
12. The display device according to aspect 11, wherein the power supply changes an amount of current flowing between the first electrode and the second electrode in accordance with the focused position of the excitation light.
[Aspect 13]
the power supply is configured to pass a current between the first electrode and the second electrode that is less than a threshold current density for amplified spontaneous emission at which the phosphor can generate amplified spontaneous emission;
13. The display device according to aspect 11 or 12, wherein the irradiating unit irradiates the excitation light having a light intensity that enables the phosphor to generate amplified spontaneous emission light.
[Aspect 14]
the second electrode includes a central electrode provided in a central portion of the second surface and a peripheral electrode provided in a peripheral portion of the second surface,
A display device described in any one of aspects 11 to 13, wherein the power supply has a first power supply for passing a current of a first current density between the first electrode and the central electrode, and a second power supply for passing a current of a second current density greater than the first current density between the first electrode and the peripheral electrode.
[Aspect 15]
A display device in which a plurality of phosphor layers containing phosphors are laminated from a first surface to a second surface, the display device comprising a first electrode provided on the first surface and a second electrode provided on the second surface;
irradiating the display body with excitation light that is incident on the display body and excites the phosphor while changing a focusing position of the excitation light within the display body.

10...display device, 12...display body, 14...first irradiation section, 16...second irradiation section, 18...control section, 20...first excitation light, 22...second excitation light, 24...focusing position, 26...first surface, 28...second surface, 30...laminated body, 31...first fluorescent layer, 32...second fluorescent layer, 33...third fluorescent layer, 40...light source, 41...collimating lens, 42...focusing lens, 44...lens driving mechanism, 46...mirror, 48...mirror driving mechanism, 50...image sensor, 52...optical sensor, 66...first electrode, 68...second electrode, 70...power source.

Claims (5)

A display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are laminated;
an irradiation unit that irradiates the display body with excitation light that is incident on the display body and excites the first phosphor and the second phosphor while changing a focusing position of the excitation light within the display body;
an optical sensor that measures the light intensity of light emitted from the display body for each wavelength;
a control unit that controls the focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor. The display includes a fluorescent layer containing an infrared phosphor having an emission wavelength in the infrared range,
The display device according to claim 1 , wherein the control unit controls a focusing position of the excitation light further based on a light intensity of an emission wavelength of the infrared phosphor measured by the optical sensor. The display includes a fluorescent layer containing a first infrared phosphor having an emission wavelength in an infrared range, and a fluorescent layer containing a second infrared phosphor having an emission wavelength in an infrared range different from that of the first infrared phosphor,
3. The display device according to claim 2, wherein the control unit controls a focusing position of the excitation light further based on the light intensity of the emission wavelength of the first infrared phosphor and the light intensity of the emission wavelength of the second infrared phosphor measured by the optical sensor. The display includes a fluorescent layer containing two or more of a plurality of types of infrared phosphors having different emission wavelengths in the infrared range,
The display device according to claim 2 , wherein the control unit controls a focusing position of the excitation light further based on the light intensity of each of the emission wavelengths of the plurality of types of infrared phosphors measured by the optical sensor. a step of irradiating an excitation light incident on a display body in which a plurality of first fluorescent layers containing a first phosphor and a plurality of second fluorescent layers containing a second phosphor having an emission wavelength different from that of the first phosphor are laminated, the excitation light exciting the first phosphor and the second phosphor, while changing a focusing position of the excitation light in the display body;
measuring the intensity of light emitted from the display by wavelength using an optical sensor;
and controlling a focusing position of the excitation light based on at least one of the light intensity of the emission wavelength of the first phosphor and the light intensity of the emission wavelength of the second phosphor measured by the optical sensor.

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