JP2019194643A - Display unit - Google Patents

Abstract

To improve the degree of transparency in a transparent state and color reproducibility in a non-transparent state of an image display body in which its optical state changes between the transparent state and non-transparent state.SOLUTION: A display unit comprises: an image display body 100 having a display function layer in which its light scattering property is increased upon reception of ultraviolet light and its light scattering property is decreased upon reception of first visible light and a light-emitting layer that emits blue light upon reception of excitation light; a first projector 200 that projects ultraviolet light on the image display body 100; a second projector 300 that projects first visible light on the image display body; a third projector 400 that projects second visible light on the image display body to display an image on the image display body 100; and a fourth projector 500 that projects excitation light on the image display body 100. When displaying an image on the image display body 100, the display unit operates the first projector 200, third projector 400, and fourth projector 500, and when not projecting an image on the image display body 100, operates the second projector 300.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a display device that displays an image.

  In recent years, a technique for displaying an image on a transparent glass such as an automobile windshield or a window glass of a building has been developed.

  In relation to this, the following Patent Document 1 has a screen in which an optical state changes between a transmission state and a scattering state by application of a voltage, and a projector that projects an image light on the screen to display an image. Display devices have been proposed. According to the display device of Patent Document 1, it is possible to display an image on the screen by temporarily making the normally transparent screen temporarily opaque.

Japanese Patent No. 5856284

  However, in the display device of Patent Document 1, a control electrode for applying a voltage is arranged inside the screen. For this reason, the display device of Patent Document 1 has a problem in that the transparency of the screen in the transparent state is low and the color reproducibility in the non-transparent state is poor because there is surface reflection and absorption at the control electrode.

  The present invention solves the above-described problems. Accordingly, an object of the present invention is to provide a display device in which the transparency in the transparent state and the color reproducibility in the non-transparent state of the image display body in which the optical state changes between the transparent state and the non-transparent state are improved. It is.

  The above object of the present invention is achieved by the following means.

  The display device of the present invention emits blue light by receiving a display function layer whose excitation light is increased and a display function layer whose light scattering property is increased by receiving ultraviolet light and light scattering property is reduced by receiving first visible light. An image display having a light emitting layer, an ultraviolet light projector that projects ultraviolet light onto the image display, a first visible light projector that projects first visible light onto the image display, and an image display A second visible light projecting unit that projects the second visible light to display an image on the image display body, and an excitation light projecting unit that projects excitation light onto the image display body. When displaying an image on the display body, the ultraviolet light projector, the second visible light projector, and the excitation light projector are operated. When not displaying an image on the image display, Activate the light section.

  According to the present invention, the transparency in the transparent state and the color reproducibility in the non-transparent state of the image display body whose optical state changes between the transparent state and the non-transparent state are improved.

1 is a perspective view illustrating a schematic configuration of a display device according to Embodiment 1. FIG. 2 is a cross-sectional view illustrating a schematic configuration of an image display body according to Embodiment 1. FIG. It is a figure which shows operation | movement of the display apparatus when making an image display body non-transparent. It is a figure which shows operation | movement of the display apparatus in the case of displaying an image on an image display body. It is a figure which shows operation | movement of the display apparatus in case an image display body is made transparent. 5 is a cross-sectional view illustrating a schematic configuration of an image display body according to Embodiment 2. FIG. 6 is a cross-sectional view illustrating a schematic configuration of an image display body according to Embodiment 3. FIG. FIG. 6 is a cross-sectional view illustrating a schematic configuration of an image display body according to a fourth embodiment. 6 is a perspective view illustrating a schematic configuration of a display device according to Embodiment 5. FIG. FIG. 10 is a diagram illustrating a configuration of an optical system of a third projector according to a fifth embodiment. It is a figure which shows the structure of the optical system of the 3rd projector which concerns on Embodiment 6. FIG. FIG. 10 is a diagram illustrating a schematic configuration of a display device according to a seventh embodiment. It is a figure which shows the structure of the optical system of the 3rd projector which concerns on Embodiment 7. FIG. FIG. 10 is a diagram illustrating a schematic configuration of a display device according to an eighth embodiment. FIG. 10 is a diagram illustrating a configuration of an optical system of a third projector according to an eighth embodiment. FIG. 10 is a cross-sectional view illustrating a schematic configuration of an image display body according to a ninth embodiment. It is sectional drawing which shows schematic structure of the image display body which concerns on Embodiment 10. FIG. It is a figure which shows the optical characteristic of the image display body which concerns on Embodiment 11. FIG. It is a figure which shows schematic structure of the display apparatus which concerns on Embodiment 11. FIG.

  Hereinafter, with reference to the drawings, embodiments of the present invention will be described by dividing them into [Embodiment 1] to [Embodiment 11]. In the drawings, the same reference numerals are used for the same members. In addition, the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may be different from the actual ratios.

[Embodiment 1]
FIG. 1 is a perspective view illustrating a schematic configuration of a display device 10 according to the first embodiment. The display device 10 of the present embodiment includes an image display body 100, a first projector 200, a second projector 300, a third projector 400, a fourth projector 500, and a control unit 600.

  The image display body 100 is a thin plate-like member whose optical state changes between a transparent state and a non-transparent state. The image display body 100 has a front surface 100a facing the fourth projector 500 from the first projector 200 and a side opposite to the front surface 100a. And a back surface 100b. The image display body 100 changes from a transparent state to a non-transparent state by receiving ultraviolet light, and changes from a non-transparent state to a transparent state by receiving first visible light. The image display body 100 is attached to a windshield of an automobile, for example. A detailed description of the image display body 100 will be described later.

  The first projector 200 is a projector that emits ultraviolet light, and is disposed to face the front surface 100 a of the image display body 100. The first projector 200 emits, for example, ultraviolet light having an intermediate wavelength of about 385 nm as an ultraviolet light projector. The first projector 200 projects ultraviolet light onto the front surface 100a of the image display body 100, and changes the ultraviolet light projection area 100c on the image display body 100 from the transparent state to the non-transparent state.

  The second projector 300 is a projector that emits visible light having a specific wavelength, and is disposed to face the front surface 100 a of the image display body 100. For example, the second projector 300 emits first visible light having an intermediate wavelength of about 450 nm as the first visible light projecting unit. The second projector 300 projects the first visible light onto the non-transparent image display body 100, and changes the ultraviolet light projection area 100c on the image display body 100 from the non-transparent state to the transparent state.

  The third projector 400 is a color projector and is disposed to face the front surface 100a of the image display body 100. The third projector 400 has, as the second visible light projector, any one of three colors of blue (intermediate wavelength is around 450 nm), green (intermediate wavelength is around 532 nm), and red (intermediate wavelength is around 640 nm). Or the second visible light which is a combination of two or more colors. The third projector 400 projects the second visible light onto the non-transparent image display body 100 and displays the image 700 on the image display body 100.

  The fourth projector 500 is a projector that emits excitation light, and is disposed to face the front surface 100 a of the image display body 100. For example, the fourth projector 500 emits excitation light having an intermediate wavelength of around 365 nm as an excitation light projector. The fourth projector 500 projects excitation light onto the image display body 100 in a non-transparent state, causes the image display body 100 to emit light in blue, and compensates for the blue color of the image 700.

  Control unit 600 controls operations of first projector 200 to fourth projector 500. The control unit 600 switches light projection / non-light projection of the first projector 200, the second projector 300, and the fourth projector 500 while communicating with a higher-level control device (not shown). In addition, the control unit 600 transmits image information to the third projector 400 while communicating with a host control device.

  Note that the first projector 200 and the third projector 400 are included so that the image 700 displayed on the image display body 100 by the second visible light is included inside the ultraviolet light projection region 100 c on the image display body 100. , And the fourth projector 500 project ultraviolet light, second visible light, and excitation light, respectively. In addition, the second projector 300 projects the first visible light so that the ultraviolet light projection region 100 c is included in the first visible light projection region on the image display body 100.

  Here, the first projector 200 radiates ultraviolet light having an intermediate wavelength of about 385 nm, and the second projector 300 emits first visible light having an intermediate wavelength of about 450 nm. In addition, the third projector 400 is configured to emit light of any one of three colors of blue (intermediate wavelength is around 450 nm), green (intermediate wavelength is around 532 nm), and red (intermediate wavelength is around 640 nm), or two colors. Exemplified is the emission of light combining the above light. Furthermore, the fourth projector 500 has exemplified that the excitation light having an intermediate wavelength of around 365 nm is emitted.

  These illustrated intermediate wavelengths are wavelengths indicating the median of the probability density function of a normal distribution. Therefore, for example, ultraviolet light having an intermediate wavelength of about 385 nm has a wavelength having a median value of a probability density function of the ultraviolet light of about 385 nm, and the ultraviolet light has a normal distribution with the wavelength of about 385 nm as a vertex. It is a curved chevron and is not composed only of light having a median wavelength. The same applies to the first visible light, the second visible light, and the excitation light.

  For example, the ultraviolet light and the excitation light, the ultraviolet light and the first visible light, and the excitation light and the first visible light may overlap each other at the base of the normal distribution curve. In the overlapping wavelength region, the ultraviolet light may act as excitation light, and the excitation light may act as ultraviolet light. The same applies to ultraviolet light and first visible light, and excitation light and first visible light. In general, if the action of one light is ¼ or less of the action of the other light in the overlapping wavelength region, there is no problem in causing the image display body 100 to function.

  Next, the image display body 100 of the display device 10 will be described in detail with reference to FIG.

  FIG. 2 is a cross-sectional view illustrating a schematic configuration of the image display body 100 according to the first embodiment. The image display body 100 according to the present embodiment includes a light emitting layer 110, a display function layer 120, and a transparent substrate 130. The light emitting layer 110 is disposed on the front surface 100a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100b side of the image display body 100. The display functional layer 120 is disposed between the light emitting layer 110 and the transparent substrate 130. The light emitting layer 110 is preferably arranged on the front surface 100a side with respect to the display function layer 120.

  The light emitting layer 110 is a film member having an optical property of emitting blue light by receiving excitation light. The blue light emitted by the light emitting layer 110 compensates for the blue color of the image displayed on the display function layer 120. The light emitting layer 110 of the present embodiment is formed using a light emitting material having a main light emission intensity in a range of about 400 nm to 480 nm which exhibits blue. The light emitting material may be either an inorganic material or an organic material. The light-emitting layer 110 is formed by appropriately dispersing a light-emitting material on a transparent resin or transparent glass such as PMMA (polymethyl methacrylate resin), PET (polyethylene terephthalate), or PC (polycarbonate) so as to be transparent. The thickness is about several μm to 100 μm so that strength can be obtained. The wavelength of the excitation light that excites the light emitting layer 110 is equal to or shorter than the light emission wavelength of the light emitting layer 110.

  The display functional layer 120 is a liquid crystal film member that includes host liquid crystal molecules and azobenzene molecules and whose optical state changes between a transparent state and a non-transparent state. The display function layer 120 has an optical characteristic that the light scattering property increases and becomes clouded by receiving ultraviolet light, and the light scattering property decreases and returns to a transparent state by receiving the first visible light. Specifically, when ultraviolet light is projected onto a transparent display functional layer in which host liquid crystal molecules are arranged substantially perpendicular to the thickness direction of the display functional layer, the azobenzene molecules that have received the ultraviolet light are transformed from the trans form to the cis form. When the structure is changed, the arrangement of the host liquid crystal molecules is disturbed, the light scattering property is increased, and the state is changed to a non-transparent state. Further, when the first visible light is projected onto the non-transparent display function layer, the structure of the azobenzene molecules changes from the cis form to the trans form, so that the host liquid crystal molecules are substantially aligned with respect to the thickness direction of the display function layer. When arranged vertically, the light scattering property decreases and the state changes to a transparent state. The display function layer 120 of this embodiment has an optical characteristic that the scattering reflectance of light in the blue wavelength region is very low (it is easy to absorb light in the blue wavelength region). For this reason, the blue color reproducibility of the image 700 (see FIG. 1) is inferior. In the present embodiment, the blue color reproducibility is compensated by blue light that the light emitting layer 110 emits by itself.

  The transparent substrate 130 is a transparent film substrate, and holds the display function layer 120 on the film substrate surface.

  Next, the operation of the display device 10 that displays an image on the image display body 100 will be described with reference to FIGS.

  FIG. 3 is a diagram illustrating the operation of the display device when the image display body 100 is non-transparent, and FIG. 4 is a diagram illustrating the operation of the display device when the image 700 is displayed on the image display body 100. FIG. 5 is a diagram illustrating the operation of the display device when the image display body 100 is transparent.

  As shown in FIG. 3, when displaying an image on the image display body 100, the first projector 200 first projects ultraviolet light onto the front surface 100 a of the image display body 100. When the ultraviolet light is projected, the display function layer 120 becomes clouded, and the ultraviolet light projection region 100c on the image display body 100 changes from the transparent state to the non-transparent state.

  Next, as shown in FIG. 4, the third projector 400 projects second visible light onto the light projection region 100 c on the image display body 100 in the non-transparent state, and the image 700 is displayed on the image display body 100. Is displayed. At the same time, the fourth projector 500 projects excitation light onto the light projecting region 100c on the image display body 100 to cause the image display body 100 to emit light in blue. Since the light projection region 100c of the image display body 100 has a low blue scattering reflectance, the blue color of the image 700 becomes light. The excitation light projected by the fourth projector 500 compensates for the light blue color, so that the color reproducibility of the image 700 is improved. The excitation light may be projected onto the entire projection area 100c of the image display body 100, but more preferably, the excitation light may be selectively projected onto the blue portion of the image 700. In this case, the fourth projector 500 projects excitation light using the blue image information transmitted from the control unit 600 to the third projector 400.

  In order to prevent the image display body 100 from returning from the non-transparent state to the transparent state by receiving the second visible light while the image 700 is displayed on the image display body 100, the first projector 200 is used. Irradiates the image display body 100 with ultraviolet light. Specifically, when at least one of the second visible light and the excitation light overlaps with the first visible light, the first projector 200 has an action to maintain a white turbid state with ultraviolet light. The ultraviolet light is projected continuously or intermittently with an output that is greater than the action of returning to the transparent state by the second visible light.

Moreover, it is preferable that the wavelength region of ultraviolet light and excitation light does not overlap in the vicinity of the intermediate wavelength. Even if there is an overlap, if the intensity of the blue light of the light emitting layer 110 excited by ultraviolet light is ¼ or less of the intensity of the blue light of the light emitting layer 110 excited by the excitation light, the color of the image 700 There is no effect on reproducibility. Even if the excitation light acts on the display function layer 120 to cause light scattering that promotes the non-transparent state of the display function layer 120, the color reproducibility of the image 700 is not affected. For example, a material (for example, Li _1.11 (Nb _0.6 Ta _0.4 ) _0.89 Ti _0.11 : Tm ³⁺ ) that is excited by excitation light having an intermediate wavelength of 365 nm to output 460 nm blue light. In the case where the light emitting layer 110 is formed, ultraviolet light having an intermediate wavelength of 385 nm which does not cause much excitation of the light emitting layer 110 is used.

  On the other hand, as shown in FIG. 5, when an image is not displayed on the image display body 100 (when the image is erased), first, the first projector 200, the third projector 400, and the fourth projector 500 are made of ultraviolet light, first 2. Stop projecting visible light and excitation light. Then, the second projector 300 projects the first visible light onto the front surface 100a of the image display body 100, and returns the ultraviolet light projection area 100c on the image display body 100 from the non-transparent state to the transparent state.

  As described above, according to the display device 10 of the present embodiment, the transparent state / non-transparent state of the image display body 100 is switched by switching between the projection / non-projection of the ultraviolet light and the first visible light. Further, the second visible light and the excitation light are projected on the non-transparent image display body 100 to display the image 700 on the non-transparent image display body 100. According to such a configuration, the image display body 100 that is normally in a transparent state can be temporarily made non-transparent to display the image 700 on the image display body 100, and the image 700 can be compensated for by compensating the blue color of the image 700. Improves color reproducibility.

  In addition, according to the display device 10 of the present embodiment, since the optical state of the image display body 100 is changed by the ultraviolet light and the first visible light, there is no need to dispose the control electrode inside the image display body 100. The transparency in the transparent state of the image display body 100 can be improved. In addition, since it is not necessary to connect an electric cable or the like to the image display body 100 and it is not necessary to secure a power supply space, the space around the image display body 100 can be saved.

  Furthermore, according to the display device 10 of the present embodiment, the image 700 having excellent color reproducibility can be displayed by superimposing the self-luminous blue light on the blue diffuse reflected light from the image display body 100. Further, in comparison with the case where the output of the blue LED array of the third projector 400 is increased in order to compensate for the blue light having a low diffuse reflectance from the image display body 100, the self-light emission using the excitation light is achieved in the present embodiment. In the case, sufficient blue light can be obtained by the excitation light having lower luminance, which can contribute to energy saving.

  As described above, the described embodiment has the following effects.

  (A) Since an image is displayed using the image display body 100 in which the transparent state and the non-transparent state are switched by switching between the projection / non-projection of the ultraviolet light and the first visible light, no control electrode is required. Therefore, since there is no reflection and absorption at the control electrode, the transparency of the image display body 100 in the transparent state can be improved.

  (B) Since the image 700 displayed on the image display body 100 by the second visible light is projected with ultraviolet light so that it is included in the ultraviolet light projection region 100c on the image display body 100, the image display body An image 700 is displayed in 100 non-transparent areas. Therefore, the image 700 is not displayed in the transparent area of the image display body 100, and the visibility of the image 700 is improved.

  (C) Since the light emitting layer 110 is disposed on the front surface 100a side of the display function layer 120, the image 700 viewed from the image display body 100 is excited by blue diffused reflected light from the image display body 100 by excitation light. It is possible to display an image 700 that is formed by overlapping the self-luminous blue light and has excellent color reproducibility.

[Embodiment 2]
The second embodiment will be described with reference to FIG. The second embodiment is an embodiment in which an ultraviolet light shielding layer is provided on the image display body 100 of the first embodiment.

  FIG. 6 is a cross-sectional view illustrating a schematic configuration of the image display body 100 according to the second embodiment. The image display body 100 of this embodiment includes a light emitting layer 110, a display function layer 120, an ultraviolet light shielding layer 140, and a transparent substrate 130. The light emitting layer 110 is disposed on the front surface 100a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100b side of the image display body 100. Between the light emitting layer 110 and the transparent substrate 130, the display functional layer 120 and the ultraviolet light shielding layer 140 are disposed. The ultraviolet light shielding layer 140 is disposed to prevent ultraviolet light from entering the display function layer 120 from the back surface 100 b of the image display body 100. Therefore, the ultraviolet light shielding layer 140 is disposed on the surface side opposite to the surface side (front side) where the ultraviolet light of the display function layer 120 is projected (front side). In this embodiment, the transparent substrate 130 is arranged on the back surface 100b side of the image display body 100. However, since the transparent substrate 130 functions as a support for other layers, the arrangement position of the transparent substrate 130 is arranged. Is not limited to this. As long as it functions as a support for another layer, the arrangement position of the transparent substrate 130 may be, for example, on the front surface 100a side of the image display body 100, or on the front surface side or the back surface side of another layer. These can be changed as appropriate.

  The ultraviolet light shielding layer 140 is a transparent film member that shields ultraviolet light. The ultraviolet light shielding layer 140 is made of a transparent resin containing an ultraviolet light reflector or an ultraviolet light absorber, and reflects or absorbs light in a wavelength region near the ultraviolet light to shield it.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (D) Since the ultraviolet light shielding layer 140 is provided on the back side of the display function layer 120, it is possible to prevent ultraviolet light from entering from the back side of the display function layer 120. Therefore, for example, when the image display body 100 is attached to a windshield of an automobile, it is possible to prevent the image display body 100 from becoming non-transparent due to sunlight or a headlight, and the transparency of the image display body 100 can be secured.

[Embodiment 3]
Embodiment 3 will be described with reference to FIG. The third embodiment is an embodiment in which a light control layer is provided on the image display body 100 of the first embodiment.

  FIG. 7 is a cross-sectional view illustrating a schematic configuration of the image display body 100 according to the third embodiment. The image display body 100 of this embodiment includes a light emitting layer 110, a display function layer 120, a light control layer 150, and a transparent substrate 130. The light emitting layer 110 is disposed on the front surface 100a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100b side of the image display body 100. The display function layer 120 and the light control layer 150 are disposed between the light emitting layer 110 and the transparent substrate 130. The light control layer 150 is disposed in order to reduce light from the back surface 100 b side of the image display body 100. Therefore, the light control layer 150 is disposed on the surface of the display function layer 120 opposite to the surface on which the ultraviolet light is projected.

  The light control layer 150 is a transparent film member whose light absorbability increases by receiving ultraviolet light. The light control layer 150 is made of a photochromic material, and has an optical characteristic that the light absorption is increased by receiving ultraviolet light and the color is changed from colorless to gray (or black). The light control layer 150 has an optical characteristic in which the light absorption is reduced by receiving blue or yellow visible light without receiving ultraviolet light or returning from gray to colorless.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (E) Since the light control layer 150 is provided on the back surface 100b side of the display function layer 120, a function of absorbing light only in a portion that receives ultraviolet light is exhibited. For this reason, the sunlight and the light of a headlight which enter from the back surface of the display function layer 120 can be absorbed. That is, contrast is maintained even in a bright environment, and visibility is improved.

[Embodiment 4]
A fourth embodiment will be described with reference to FIG. The fourth embodiment is an embodiment in which the image display body 100 of the first embodiment is provided with an ultraviolet light shielding layer and a light control layer.

  FIG. 8 is a cross-sectional view illustrating a schematic configuration of the image display body 100 according to the fourth embodiment. The image display body 100 according to the present embodiment includes a light emitting layer 110, a display function layer 120, a light control layer 150, an ultraviolet light shielding layer 140, and a transparent substrate 130. The light emitting layer 110 is disposed on the front surface 100a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100b side of the image display body 100. Between the light emitting layer 110 and the transparent substrate 130, the display function layer 120, the light control layer 150, and the ultraviolet light shielding layer 140 are disposed. The ultraviolet light shielding layer 140 is disposed to prevent ultraviolet light from entering the display function layer 120 from the back surface 100 b of the image display body 100. The light control layer 150 is disposed in order to reduce light from the back surface 100b side of the image display body 100. Therefore, the light control layer 150 and the ultraviolet light shielding layer 140 are disposed on the surface of the display function layer 120 opposite to the surface on which the ultraviolet light is projected. In addition, the light control layer 150 is arrange | positioned rather than the ultraviolet light shielding layer 140 at the front surface 100a side.

  The configuration of the ultraviolet light shielding layer 140 is the same as that of the second embodiment, and the configuration of the light control layer 150 is the same as that of the third embodiment. For this reason, the image display body 100 of this embodiment increases light scattering and light absorption by receiving ultraviolet light, and decreases light scattering and light absorption by receiving first visible light. .

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (F) Since the light control layer 150 and the ultraviolet light shielding layer 140 are provided on the back surface 100b side of the display function layer 120, it is possible to prevent ultraviolet light from entering from the back surface 100b side of the image display body 100. In addition, the function of absorbing light is exhibited only in the portion that receives ultraviolet light from the front surface 100a side of the image display body 100. For this reason, when the image display body 100 is attached to the windshield of an automobile, sunlight and headlight light incident from the back of the display function layer 120 can be absorbed, and the image display body 100 is made opaque by the sunlight and the headlight. And the transparency of the image display body 100 can be secured. That is, the contrast is maintained even in a bright environment with a lot of ultraviolet rays, and visibility is improved.

[Embodiment 5]
Embodiment 5 will be described with reference to FIGS. 9 and 10. In the fifth embodiment, the second visible light and the excitation light are projected from one projector.

  FIG. 9 is a perspective view illustrating a schematic configuration of the display device 10 according to the fifth embodiment. The display device 10 of this embodiment includes an image display body 100, a first projector 200, a second projector 300, a third projector 400, and a control unit 600. The configuration of the display device 10 according to the present embodiment is the same as that of the embodiment except that the fourth projector 500 is removed and the excitation light and the second visible light are projected from one third projector 400. Since it is the same as that of the form 1, description about the display apparatus 10 is abbreviate | omitted.

  FIG. 10 is a diagram illustrating a configuration of an optical system of the third projector 400 according to the fifth embodiment. As illustrated, the optical system of the third projector 400 includes a blue LED array 410, a green LED array 420, a red LED array 430, dichroic mirrors 415, 425, and 435, and an excitation light LED array 510. The dichroic mirror 415 reflects only blue light and transmits excitation light. The dichroic mirror 425 reflects only green light and transmits excitation light and blue light. The dichroic mirror 435 reflects only red light and transmits excitation light, blue light, and green light. Therefore, the third projector 400 according to the present embodiment is obtained by integrating the fourth projector 500 with the third projector 400 according to the first embodiment.

  The second visible light is projected from three LED arrays, a blue LED array 410, a green LED array 420, and a red LED array 430. Excitation light is projected from the excitation light LED array 510. When the blue LED array 410, the green LED array 420, the red LED array 430, and the excitation light LED array 510 are simultaneously operated, the second visible light and the excitation light are projected from the third projector 400. Since the excitation light is projected to compensate for blue light, the excitation light LED array 510 is preferably operated with the same image information as the blue LED array 410.

  In the display device 10 of the present embodiment, when displaying an image, first, the first projector 200 projects ultraviolet light onto the front surface 100a of the image display body 100. Then, the third projector 400 projects the second visible light and the excitation light on the front surface 100a of the image display body 100 to display the image 700. On the other hand, when the image is not displayed (when the image is deleted), first, the first projector 200 stops the ultraviolet light projection. Then, the second projector 300 projects the first visible light onto the front surface 100a of the image display body 100 to return the image display body 100 from the non-transparent state to the transparent state. According to such a configuration, a projector dedicated to excitation light is omitted, and the device configuration is simplified.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (G) Since one projector projects the second visible light and the excitation light, the device configuration of the display device 10 can be simplified, and the cost of the display device 10 can be reduced.

  (H) Since the number of projectors is reduced, the installation space for the projector can be omitted, and the degree of freedom in layout is improved.

  (I) Since the excitation light and the second visible light can be projected by one projector, it is unnecessary to adjust the projection position of the excitation light and the second visible light to a blue image.

  (J) Since the excitation light may be projected in synchronization with the blue color of the second visible light, the control of the projection becomes easy.

[Embodiment 6]
Embodiment 6 will be described with reference to FIG. In the sixth embodiment, excitation light is used as blue light of the second visible light. The display device 10 of the present embodiment is the same as the present embodiment except that the fourth projector 500 is removed and the excitation light and the second visible light other than blue are projected from one third projector 400. Since the configuration of the display device 10 according to the second embodiment is the same as that of the first embodiment, the description of the display device 10 is omitted.

  FIG. 11 is a diagram illustrating a configuration of an optical system of the third projector 400 according to the sixth embodiment. As illustrated, the optical system of the third projector 400 includes a green LED array 420, a red LED array 430, dichroic mirrors 425 and 435, and an excitation light LED array 510. The dichroic mirror 425 reflects only green light and transmits excitation light. The dichroic mirror 435 reflects only red light and transmits excitation light and green light.

  The second visible light is projected from two LED arrays, a green LED array 420 and a red LED array 430. Excitation light is projected from the excitation light LED array 510. In the case of this embodiment, the intermediate wavelength of the excitation light projected from the excitation light LED array 510 is a wavelength close to the blue intermediate wavelength of the second visible light. For this reason, in the part where the wavelength of excitation light overlaps with the blue wavelength of 2nd visible light, excitation light acts also as blue of 2nd visible light. Therefore, when the green LED array 420, the red LED array 430, and the excitation light LED array 510 are simultaneously operated, the excitation light and the green and red second visible light are projected from the third projector 400, and the second visible light is emitted. Blue can be expressed by the light emitting action of the light emitting layer 110 of the image display body 100.

  The display device 10 of the present embodiment is the same as that of the fifth embodiment when displaying an image and when not displaying an image (when deleting an image).

  As described above, the present embodiment described has the following effects in addition to the effects of the fifth embodiment.

  (K) Since the blue LED array becomes unnecessary, the installation space for the LED array can be further omitted, and the degree of freedom in layout is improved.

  (L) When displaying an image, the excitation light may be projected using the image information of the blue light of the second visible light, so that the control of the projection becomes easy.

  (M) When displaying an image, it is only necessary to project the ultraviolet light in synchronization with the second visible light, so that the control of the projection becomes easy.

[Embodiment 7]
Embodiment 7 will be described with reference to FIGS. 12 and 13. In the seventh embodiment, the second visible light, the excitation light, and the ultraviolet light are projected from one projector.

  FIG. 12 is a perspective view illustrating a schematic configuration of the display device 10 according to the seventh embodiment. The display device 10 of this embodiment includes an image display body 100, a second projector 300, a third projector 400, and a control unit 600. It should be noted that the first projector 200 and the fourth projector 500 are removed, and the second visible light, excitation light, and ultraviolet light are emitted from one third projector 400, according to the present embodiment. Since the configuration of the display device 10 is the same as that of the first embodiment, description of the display device 10 is omitted.

  FIG. 13 is a diagram illustrating a configuration of an optical system of the third projector 400 according to the seventh embodiment. As illustrated, the optical system of the third projector 400 includes an ultraviolet light LED array 210, an excitation light LED array 510, a blue LED array 410, a green LED array 420, and a red LED array 430, dichroic mirrors 515, 415, 425, 435. The dichroic mirror 515 reflects only excitation light and transmits ultraviolet light. The dichroic mirror 415 reflects only blue light and transmits ultraviolet light and excitation light. The dichroic mirror 425 reflects only green light and transmits ultraviolet light, excitation light, and blue light. The dichroic mirror 435 reflects only red light and transmits ultraviolet light, excitation light, blue light, and green light. Therefore, the third projector 400 according to the present embodiment is obtained by integrating the first projector 200 and the fourth projector 500 with the third projector 400 according to the first embodiment.

  The second visible light is projected from three LED arrays, a blue LED array 410, a green LED array 420, and a red LED array 430. The ultraviolet light is projected from the ultraviolet LED array 210. Excitation light is projected from the excitation light LED array 510. When the ultraviolet LED array 210 is operated alone, the third projector 400 emits ultraviolet light. When the blue LED array 410, the green LED array 420, the red LED array 430, and the excitation light LED array 510 are simultaneously operated, the second visible light and the excitation light are projected from the third projector 400. Since the excitation light is projected to compensate for blue light, the excitation light LED array 510 is preferably operated with the same image information as the blue LED array 410.

  In the display device 10 of the present embodiment, when displaying an image, first, the third projector 400 projects ultraviolet light onto the front surface 100a of the image display body 100. Similarly, the third projector 400 projects the second visible light and the excitation light on the front surface 100 a of the image display body 100 to display the image 700. On the other hand, when the image is not displayed (when the image is deleted), first, the third projector 400 stops the projection of the ultraviolet light. Then, the second projector 300 projects the first visible light onto the front surface 100a of the image display body 100 to return the image display body 100 from the non-transparent state to the transparent state. According to such a configuration, a projector dedicated to ultraviolet light and excitation light is omitted, and the device configuration is simplified.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (N) Since one projector projects the second visible light, excitation light, and ultraviolet light, the device configuration of the display device 10 can be simplified, and the cost of the display device 10 can be reduced.

  (O) Since the number of projectors is reduced, the installation space for the projector can be omitted, and the degree of freedom in layout is improved.

  (P) Since the second visible light, excitation light, and ultraviolet light can be projected by a single projector, it is not necessary to adjust the projection positions of the second visible light, excitation light, and ultraviolet light.

  (Q) Since the excitation light may be projected in synchronization with the blue color of the second visible light, the control of the projection becomes easy.

[Embodiment 8]
Embodiment 8 will be described with reference to FIGS. 14 and 15. In the eighth embodiment, the first visible light, the second visible light, the excitation light, and the ultraviolet light are projected from one projector.

  FIG. 14 is a perspective view illustrating a schematic configuration of the display device 10 according to the eighth embodiment. The display device 10 of this embodiment includes an image display body 100, a third projector 400, and a control unit 600. The configuration of the display device 10 according to the present embodiment is implemented except that the first visible light, the second visible light, the excitation light, and the ultraviolet light are projected from one third projector 400. Since it is the same as that of the form 1, description about the display apparatus 10 is abbreviate | omitted.

  FIG. 15 is a diagram illustrating a configuration of an optical system of the third projector 400 according to the eighth embodiment. As illustrated, the optical system of the third projector 400 includes a first visible light LED array 310, an ultraviolet light LED array 210, an excitation light LED array 510, a blue LED array 410, a green LED array 420, and a red LED array 430. Dichroic mirrors 215, 515, 415, 425, 435 are provided. The dichroic mirror 215 reflects only the ultraviolet light and transmits the first visible light. The dichroic mirror 515 reflects only the excitation light and transmits the first visible light and the ultraviolet light. The dichroic mirror 415 reflects only blue light and transmits first visible light, ultraviolet light, and excitation light. The dichroic mirror 425 reflects only green light and transmits first visible light, ultraviolet light, excitation light, and blue light. The dichroic mirror 435 reflects only red light and transmits first visible light, ultraviolet light, excitation light, blue light, and green light. Therefore, the third projector 400 according to the present embodiment is obtained by integrating the first projector 200, the second projector 300, and the fourth projector 500 with the third projector 400 according to the first embodiment.

  The second visible light is projected from three LED arrays, a blue LED array 410, a green LED array 420, and a red LED array 430. Excitation light is projected from the excitation light LED array 510. The ultraviolet light is projected from the ultraviolet LED array 210. The first visible light is projected from the first visible light LED array 310. When the ultraviolet LED array 210 is operated alone, the third projector 400 emits ultraviolet light. Further, when the blue LED array 410, the green LED array 420, the red LED array 430, and the excitation light LED array 510 are simultaneously operated, the second visible light and the excitation light are projected from the third projector 400. When the first visible light LED array 310 is operated alone, the first visible light is projected from the third projector 400. Since the excitation light is projected to compensate for blue light, the excitation light LED array 510 is preferably operated with the same image information as the blue LED array 410.

  In the display device 10 of the present embodiment, when displaying an image, first, the third projector 400 projects ultraviolet light onto the front surface 100a of the image display body 100. Similarly, the third projector 400 projects the second visible light and the excitation light on the front surface 100 a of the image display body 100 to display the image 700. On the other hand, when the image is not displayed (when the image is deleted), first, the third projector 400 stops the projection of the ultraviolet light. Then, the third projector 400 projects the first visible light onto the front surface 100a of the image display body 100 to return the image display body 100 from the non-transparent state to the transparent state. According to such a configuration, the projector dedicated to the first visible light, the ultraviolet light, and the excitation light is omitted, and the device configuration is simplified.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (R) Since one projector projects the first visible light, the second visible light, the excitation light, and the ultraviolet light, the device configuration of the display device 10 can be simplified, and the cost of the display device 10 can be reduced.

  (S) Since the number of projectors is reduced, the installation space for the projector can be omitted, and the degree of freedom in layout is improved.

  (T) Since the first visible light, the second visible light, the excitation light, and the ultraviolet light can be projected by one projector, the projection positions of the first visible light, the second visible light, the excitation light, and the ultraviolet light can be determined. Adjustment to match is unnecessary.

  (U) Since the excitation light may be projected in synchronization with the blue color of the second visible light, the control of the projection becomes easy.

[Embodiment 9]
Embodiment 9 will be described with reference to FIG. The ninth embodiment is an embodiment in which the display functional layer 120 of the image display body 100 also serves as the light emitting layer 110. Therefore, in the present embodiment, the image display body 100 is not provided with the light emitting layer 110 as in the first embodiment.

  FIG. 16 is a cross-sectional view illustrating a schematic configuration of an image display body according to the ninth embodiment. The image display body 100 of this embodiment includes a display functional layer 160 to which a light emitting material is added, and a transparent substrate 130. The display function layer 160 is disposed on the front surface 100a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100b side of the image display body 100.

  The display function layer 160 emits blue light while changing its optical state between a transparent state and a non-transparent state. The blue color emitted by the display function layer 160 compensates for the blue color of the image displayed on the display function layer 160.

The display function layer 160 receives the ultraviolet light and increases its light scattering property and becomes clouded. By receiving the first visible light, the display functional layer 160 returns to the transparent state and receives the excitation light. By doing so, it has an optical characteristic of emitting blue light. The display functional layer 160 of this embodiment is a liquid crystal film containing host liquid crystal molecules and azobenzene molecules, in which a light emitting material having a main light emission intensity in the range of about 400 nm to 480 nm which is blue is added by about 1% by weight. is there. The light emitting material may be either an inorganic material or an organic material. For example, a light emitting material such as Li _1.11 (Nb _0.6 Ta _0.4 ) _0.89 Ti _0.11 : Tm ³⁺ is used. preferable. A liquid crystal film containing host liquid crystal molecules and azobenzene molecules has an optical characteristic that the scattering reflectance of light in the blue wavelength region is very low (it is easy to absorb light in the blue wavelength region). For this reason, in this embodiment, a light emitting material that emits blue light with excitation light is added to this film to compensate for the optical characteristics of the blue wavelength region of the liquid crystal film containing host liquid crystal molecules and azobenzene molecules.

  In addition, although the addition amount of the light emitting material is illustrated as about 1% by weight, the addition amount may be 1% or less. Even if a luminescent material is added, the light-scattering property increases and becomes clouded by receiving ultraviolet light, and the light-scattering property decreases and returns to the transparent state by receiving first visible light. The basic optical characteristics of 160 are not affected.

  In the present embodiment, the image 700 is projected by the display device 10 illustrated in FIG.

  As shown in FIG. 3, when displaying an image on the image display body 100, the first projector 200 first projects ultraviolet light onto the front surface 100 a of the image display body 100. When the ultraviolet light is projected, the display function layer 160 becomes clouded, and the ultraviolet light projection region 100c on the image display body 100 changes from the transparent state to the non-transparent state.

  Next, as shown in FIG. 4, the third projector 400 projects second visible light onto the light projection region 100 c on the image display body 100 in the non-transparent state, and the image 700 is displayed on the image display body 100. Is displayed. At the same time, the fourth projector 500 projects excitation light onto the light projecting region 100c on the image display body 100, and causes the display function layer 160 of the image display body 100 to emit blue light. Since the display functional layer 160 emits blue light, the color reproducibility of the image 700 is improved. The excitation light may be projected onto the entire projection area 100c of the image display body 100, but more preferably, the excitation light may be selectively projected onto the blue portion of the image 700. In this case, the fourth projector 500 projects excitation light using the blue image information transmitted from the control unit 600 to the third projector 400.

  In order to prevent the image display body 100 from returning from the non-transparent state to the transparent state by receiving the second visible light and the excitation light while the image 700 is displayed on the image display body 100, One projector 200 projects ultraviolet light onto the image display body 100 continuously or intermittently.

  On the other hand, as shown in FIG. 5, when an image is not displayed on the image display body 100 (when the image is erased), first, the first projector 200, the third projector 400, and the fourth projector 500 are made of ultraviolet light, first 2. Stop projecting visible light and excitation light. Then, the second projector 300 projects the first visible light onto the front surface 100a of the image display body 100, and returns the ultraviolet light projection area 100c on the image display body 100 from the non-transparent state to the transparent state.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (V) Since the image display body 100 can be configured only by the display function layer 160 to which the light emitting material is added, the layer structure of the image display body 100 is simplified, and the thickness of the image display body 100 can be reduced. it can. Moreover, the manufacturing cost of the image display body 100 can be reduced.

[Embodiment 10]
The tenth embodiment will be described with reference to FIG. The tenth embodiment is an embodiment in which the display function layer 120 is disposed between the transparent substrate 130 and the display function layer 160 of the image display body 100 of the ninth embodiment.

  FIG. 17 is a cross-sectional view illustrating a schematic configuration of the image display body according to the tenth embodiment. The image display body 100 of this embodiment includes a display functional layer 160 to which a light emitting layer is added, a display functional layer 120 to which a light emitting layer is not added, and a transparent substrate 130. The display function layer 160 is disposed on the front surface 100 a side of the image display body 100, and the transparent substrate 130 is disposed on the back surface 100 b side of the image display body 100, and the display function layer 120 is disposed between the display function layer 160 and the transparent substrate 130. Is placed.

  As in the ninth embodiment, the display function layer 160 receives the ultraviolet light to increase the light scattering property and become clouded, and receives the first visible light to reduce the light scattering property and return to the transparent state. Moreover, it has the optical characteristic of emitting blue light by receiving excitation light. Further, as in the first embodiment, the display function layer 120 increases in light scattering by receiving ultraviolet light and becomes white turbid, and by receiving first visible light, the light scattering decreases and becomes transparent. Has returning optical properties.

  The display function layer 160 is disposed on the front surface 100 a side of the display function layer 120. The display function layer 160 is thinner than the display function layer 120. When the display function layer 160 receives excitation light, the added light emitting material emits blue light. However, the excitation light acts on the display functional layer 160 only on the surface portion of the display functional layer 160, and does not extend deeply. For this reason, in the present embodiment, the thickness of the display function layer 160 is reduced so that the action of the excitation light reaches the entire display function layer 160. However, when the thickness of the display function layer 160 is reduced, there is a problem that the original optical characteristics of the display function layer 120 cannot be sufficiently obtained when ultraviolet light or first visible light is received. The display functional layer 120 is provided on the back surface 100 b side of the functional layer 160.

  In the present embodiment, the image 700 is projected by the display device 10 illustrated in FIG. The operation of the display device 10 when displaying an image on the image display body 100 and when not displaying the image is the same as that of the ninth embodiment.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (W) Since the thin display function layer 160 to which the light emitting material is added is provided on the front surface 100 a side of the display function layer 120, the light emitting material to be added to the display function layer 160 can be minimized, and the image display body 100. The manufacturing cost can be reduced.

[Embodiment 11]
The eleventh embodiment will be described with reference to FIGS. Embodiment 11 is an embodiment in which the image display body 100 emits blue light by light in a specific wavelength region.

  The laminated structure of the image display body 100 of this embodiment is the same as the image display body 100 of Embodiment 1 shown in FIG. However, in the present embodiment, the optical characteristics of the light emitting layer 110 of the image display body 100 are different from the optical characteristics of the light emitting layer 110 of the first embodiment.

  FIG. 18 is a diagram illustrating optical characteristics of the image display body 100 according to the eleventh embodiment. Looking at the optical characteristics in this figure, the peak wavelength 439 nm of the excitation wavelength characteristic and the peak wavelength 442 nm of the emission spectrum are very close. When the light emitting layer 110 of the image display body 100 has such optical characteristics, the second visible light (particularly blue light) that displays the image 700 on the image display body 100 works as excitation light. Even without this, the light emitting layer 110 can be excited. As described above, when the optical characteristics of the light emitting layer 110 and the optical characteristics of the light sources are matched, the number of light sources can be reduced.

  Therefore, in the present embodiment, the fourth projector 500 that projects the excitation light, which the display device 10 of the first embodiment has, becomes unnecessary.

  FIG. 19 is a diagram illustrating a schematic configuration of a display device according to the eleventh embodiment. In the present embodiment, since the light emitting layer 110 can be excited by the blue light of the second visible light, the first projector 200 to the third projector 400 are provided. The light projected from the first projector 200 to the third projector 400 onto the image display body 100 is the same as that of the first projector 200 to the third projector 400 of the first embodiment.

  In the present embodiment, the image 700 is projected by the display device 10 of FIG.

  As shown in FIG. 19, when displaying an image on the image display body 100, first, the first projector 200 projects ultraviolet light onto the front surface 100 a of the image display body 100. When the ultraviolet light is projected, the display function layer 160 becomes clouded, and the ultraviolet light projection region 100c on the image display body 100 changes from the transparent state to the non-transparent state.

  Next, the third projector 400 projects the second visible light onto the light projection area 100 c on the image display body 100 in the non-transparent state, and displays the image 700 on the image display body 100. At this time, the blue light contained in the second visible light excites the light emitting layer 110 of the image display body 100 to emit blue light. Since the light emitting layer 110 emits blue light, the color reproducibility of the image 700 is improved.

  In order to prevent the image display body 100 from returning from the non-transparent state to the transparent state by receiving the second visible light while the image 700 is displayed on the image display body 100, the first projector 200 is used. Irradiates the image display body 100 with ultraviolet light continuously or intermittently.

  On the other hand, when an image is not displayed on image display body 100 (when the image is erased), first and third projectors 200 and 400 first stop projecting ultraviolet light and second visible light, respectively. Then, the second projector 300 projects the first visible light onto the front surface 100a of the image display body 100, and returns the ultraviolet light projection area 100c on the image display body 100 from the non-transparent state to the transparent state.

  In the present embodiment, the blue light included in the second visible light is exemplified as the light in the specific wavelength region, but ultraviolet light may be used as long as it matches the optical characteristics of the light emitting layer 110.

  As described above, the described embodiment has the following effects in addition to the effects of the first embodiment.

  (X) Since the light emitting layer 110 of the image display body 100 can be excited by the blue light contained in the second visible light, the number of projectors can be reduced, the installation space for the projectors can be omitted, and the degree of layout freedom is improved. .

  As described above, the display device 10 of the present invention has been described in the first to eleventh embodiments. However, the present invention can be appropriately added, modified, and omitted by those skilled in the art within the scope of the technical idea.

10 display device,
100 image display,
100a front side,
100b back,
100c Projection area,
110 light emitting layer,
120 display functional layer,
130 transparent substrate,
140 UV light shielding layer,
150 light control layer,
160 a display functional layer to which a light emitting material is added,
200 First projector (ultraviolet light projector),
210 UV LED array,
215, 415, 425, 435, 515 dichroic mirror,
300 Second projector (first visible light projector),
310 first visible light LED array,
400 third projector (second visible light projector),
410 blue LED array,
420 green LED array,
430 red LED array,
500 Fourth projector (excitation light projector),
510 excitation light LED array,
600 control unit,
700 images.

Claims (11)

A display function layer that increases light scattering by receiving ultraviolet light and decreases light scattering by receiving first visible light; and a light emitting layer that emits blue light by receiving excitation light. An image display;
An ultraviolet light projector for projecting the ultraviolet light on the image display body;
A first visible light projecting unit that projects the first visible light on the image display body;
A second visible light projector that projects second visible light on the image display and displays an image on the image display;
An excitation light projector for projecting the excitation light on the image display body,
When displaying the image on the image display body, when operating the ultraviolet light projector, the second visible light projector, and the excitation light projector, and not displaying the image on the image display A display device for operating the first visible light projector. The image display body is:
The display device according to claim 1, wherein the light emitting layer is disposed on a surface side on which the excitation light is projected with respect to the display function layer. The image display body is:
The display device according to claim 1, wherein an ultraviolet light shielding layer that shields the ultraviolet light is further disposed on a surface side of the display function layer opposite to a surface on which the ultraviolet light is projected. The image display body is:
The light control layer which light absorption increases by receiving the said ultraviolet light is further arrange | positioned by the surface side on the opposite side to the surface side where the said ultraviolet light is projected of the said display function layer. Or the display apparatus of 3. The image display body is:
The display device according to claim 4, wherein the light scattering property and the light absorption property are increased by receiving the ultraviolet light, and the light scattering property and the light absorption property are decreased by receiving the first visible light.   One or more or all of the excitation light projecting unit, the ultraviolet light projecting unit, the first visible light projecting unit, and the second visible light projecting unit have a single projecting unit. The display device according to claim 1, wherein the display device is integrated as a display device. The second visible light projecting unit is
The display according to claim 6, comprising a green LED array that projects light in a green wavelength region, a red LED array that projects light in a red wavelength region, and an excitation light LED array that projects the excitation light. apparatus. An image display that emits blue light by receiving excitation light and receiving light of ultraviolet light and increasing light scattering and reducing light scattering by receiving first visible light;
An ultraviolet light projector for projecting the ultraviolet light on the image display body;
A first visible light projecting unit that projects the first visible light on the image display body;
A second visible light projector that projects second visible light on the image display and displays an image on the image display;
An excitation light projector for projecting the excitation light on the image display body,
When displaying the image on the image display body, when operating the ultraviolet light projector, the second visible light projector, and the excitation light projector, and not displaying the image on the image display A display device for operating the first visible light projector. The image display body is:
The display device according to claim 8, further comprising: a display function layer to which a light emitting material that emits blue light by receiving the excitation light is added, and the display function layer also serves as a light emitting layer. A display function layer that increases light scattering by receiving ultraviolet light and decreases light scattering by receiving first visible light; a light emitting layer that emits blue light by receiving light in a specific wavelength region; An image display body having
An ultraviolet light projector for projecting the ultraviolet light on the image display body;
A first visible light projecting unit that projects the first visible light on the image display body;
A second visible light projecting unit that projects second visible light including light of a specific wavelength region on the image display body and displays an image on the image display body,
When displaying the image on the image display, the ultraviolet light projector and the second visible light projector are operated, and when not displaying the image on the image display, the first visible light projector. A display device that operates the unit.   The display device according to claim 10, wherein the light in the specific wavelength region is at least one of the ultraviolet light and the second visible light.