JP7128541B2 - Display device - Google Patents

Description

The present invention relates to display devices .

In recent years, in fields such as communication/broadcasting, entertainment, art, and medicine, aerial display technology that can display images in three-dimensional space without using special glasses, etc., using the environment and space has been developed. Attention has been paid. Aerial Imaging by Retro-Reflection (AIRR) using retroreflection is known as one of the methods for displaying an image in a three-dimensional space as described above (see, for example, Non-Patent Document 1). .

A display device 101 shown in FIG. 51 is an example of the configuration of the AIRR, and includes a light source S provided in the display D1 or the like, a half mirror 104, and a retroreflector . Part of the light L101 of the light L1 emitted from the light source S is reflected by the half mirror 104 as reflected light L102. The reflected light L102 enters the retroreflecting portion 106, is reflected by the retroreflecting portion 106 in the same direction as the incident direction, enters the half mirror 104 as reflected light L103, passes through the half mirror 104, and reaches the half mirror 104. On the other hand, an aerial image I is formed at a position Q1 that is plane-symmetrical to the display D1. The user can see the aerial image I displayed in the space A (that is, the space where the user is with respect to the half mirror 104) from the observation direction E0 on the side opposite to the light source S with respect to the half mirror 104. Here, the aerial image I that the user can observe is limited to the range in which the retroreflector 106 can be seen through the half mirror 104 from the user's viewpoint position. Even if the aerial image I is formed, the user can only observe the aerial image within a certain area Z1.

In addition, Patent Document 1 discloses, as an example of a configuration with a reduced number of parts, a beam splitting device placed in the path of light from an object (light source), and light from the object transmitted or reflected by the beam splitting device. A display device is disclosed having retroreflection means placed in the passage of the light. In the display device described in US Pat. No. 5,400,000, beam splitting devices are mounted in openings in an opaque surface.

Japanese Patent Publication No. 9-506717

H. Yamamoto, Y.; Tomiyama, S, Suyama, "Floating aerial LED signage based on aerial imaging by retro-reflection (AIRR)", Optics Express, Vol. 22, No. 22, pp. 26919-26924 (2014).

However, in the display device 101 shown in FIG. 51, part of the lights L105 and L108 out of the light L1 are reflected by the half mirror 104 and then enter the display D as the reflected lights L106 and L109. Does not contribute to formation. That is, in the conventional display device based on AIRR, since the light L1 includes the light 105 that does not form the aerial image I, there is a problem that the angle θ101 at which the aerial image I can be seen becomes small.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a display device that enables an image formed in the air (an aerial image) to be observed from a wider angle.

A display device according to the present invention includes a first light source that emits a first light , and a first light branching section and a second light branching section that are arranged to face each other with the first light source interposed in the first direction. and a retroreflective portion disposed on a side of one of the first optical branching portion and the second optical branching portion opposite to a side facing the other optical branching portion , The light branching part reflects part of the first light from the first light source as the first reflected light, transmits another part of the first light, and is reflected by the other light branching part. A part of the first reflected light is reflected and another part of the first reflected light is transmitted, and the retroreflective section transmits the first light and the first reflected light transmitted through the one light branching section. is retroreflected.

In the display device according to the aspect of the invention , the retroreflective section may be arranged with a predetermined gap from the one light branching section in the first direction.

In the display device according to the present invention, the surface of the one optical branching portion facing the other optical branching portion is inclined with respect to the surface of the other optical branching portion facing the one optical branching portion. may

A display device according to the present invention comprises: a first light source that emits a first light; a second light source that emits a second light; A first light branching portion and a retroreflecting portion are arranged to face each other, and the first light branching portion reflects a part of the first light from the first light source to convert the first light while transmitting another part of the light reflected by the retroreflective part, reflecting part of the second light from the second light source, transmitting another part of the second light, and part of the light reflected by the retroreflection part is transmitted, and the retroreflection part is reflected by the first light, the second light, and the first light branching part retroreflect at least a portion of each of the emitted light.

The display device according to the present invention further includes a second light branching section disposed on a side of the retroreflective section facing the first light branching section in the first direction, wherein the second light branching section Reflecting part of the first light from the first light source and part of the second light from the second light source, and reflecting another part of the first light and another part of the second light and a part of the light reflected by the first light branching section may be reflected and another part of the light reflected by the first light branching section may be transmitted.

In the display device and aerial image display method of the present invention, at least part of the first light emitted from the first light source is reflected as the first reflected light by the first light branching section, and then the first retroreflected light The light can be reflected by the reflecting portion toward the first light branching portion, pass through the first light branching portion, and form an aerial image. That is, since the first reflected light reaches a position where no aerial image is formed in the conventional display device, an aerial image can be formed. Therefore, according to the present invention, it is possible to provide a display device and an aerial image display method that make it possible to observe an aerial image from a wider range of angles.

1 is a schematic diagram showing the configuration of a display device according to a first embodiment of the present invention; FIG. FIG. 4 is a side view showing a first example of the structure of the retroreflective portion used in the display device of the first embodiment according to the invention; FIG. 4B is a side view showing a second example of the structure of the retroreflective portion used in the display device according to the first embodiment of the present invention; It is a schematic diagram showing the configuration of a display device of a second embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device of a third embodiment according to the present invention. It is a schematic diagram showing a configuration of a modification of the display device of the third embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device of a fourth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device according to a fifth embodiment of the present invention. It is a schematic diagram showing the configuration of a display device according to a sixth embodiment of the present invention. FIG. 10 is a plan view of a fourth display of the display device shown in FIG. 9; It is a schematic diagram showing the configuration of a display device that is a first modification of the sixth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device that is a second modification of the sixth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device of a seventh embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device of an eighth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device of a ninth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device that is a first modified example of the ninth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device that is another modification of the ninth embodiment according to the present invention. It is a schematic diagram showing the configuration of a display device that is a second modification of the ninth embodiment according to the present invention. It is a schematic diagram showing the configuration of the display device of the tenth embodiment according to the present invention. It is a schematic diagram showing another configuration of the display device of the tenth embodiment according to the present invention. It is a schematic diagram showing still another configuration of the display device of the tenth embodiment according to the present invention. It is a schematic diagram showing another configuration of the display device of the tenth embodiment according to the present invention. It is a schematic diagram showing still another configuration of the display device of the tenth embodiment according to the present invention. It is a schematic diagram showing the configuration of a first modification of the display device according to the present invention. It is a schematic diagram showing the configuration of a second modification of the display device according to the present invention. 1 is a schematic diagram showing the configuration of a display device according to the present invention housed in a housing; FIG. It is a schematic diagram showing an example of use of the display device according to the present invention. 4 is a photograph of an aerial image displayed by the display device 1A of Example 1 and direct transmitted light from a light source. 10A and 10B are photographs of an aerial image displayed by the display device 1E of Example 2 and direct transmitted light from the light source. 10A and 10B are photographs of an aerial image displayed by the display device 1G of Example 3 and direct transmitted light from the light source. 10A and 10B are photographs of an aerial image displayed by the display device 1G' of Example 3 and direct transmitted light from a light source. 10 is a photograph of an aerial image displayed by the display device 1H of Example 4 and direct transmitted light from the light source. 10 is a photograph of an aerial image displayed by the display device 1K of Example 5 and direct transmitted light from the light source. 11 is a photograph of an aerial image displayed by the display device 1P of Example 6. FIG. 10 is a photograph of an aerial image displayed by the display device 1Q of Example 6. FIG. 10 is an output image of the special color display used in Example 7 and Comparative Example 1. FIG. 4 is a photograph of an aerial image displayed by the display device CT of Comparative Example 1. FIG. 10 is a photograph of an aerial image displayed by the display device 1T(1) of Example 7. FIG. 11 is a photograph of an aerial image displayed by the display device 1T(2) of Example 7. FIG. 13 is a photograph of an aerial image displayed by the display device 1T(3) of Example 7. FIG. 11 is a photograph of an aerial image displayed by the display device 1T(4) of Example 7. FIG. 20 is a photograph of the aerial image displayed by the display device 1T(2) of Example 8 taken on the left side facing the aerial image. FIG. 13 is a photograph of an aerial image displayed by the display device 1T(2) of Example 8 taken in the front facing the aerial image. FIG. 20 is a photograph of the aerial image displayed by the display device 1T(2) of Example 8 taken on the right side facing the aerial image. FIG. 21 is a photograph of another aerial image displayed by the display device 1T(2) of Example 8 taken on the left in a direction directly facing the aerial image; FIG. FIG. 21 is a photograph of another aerial image displayed by the display device 1T(2) of Example 8 taken from the front facing the aerial image. FIG. 20 is a photograph of another aerial image displayed by the display device 1T(2) of Example 8 taken on the right side facing the aerial image. FIG. 11 is a schematic diagram showing the configuration of a display device of Example 9; 10 is a photograph of an aerial image displayed before the wave plate 53 is arranged in the display device of Example 9. FIG. 11 is a photograph of an aerial image displayed when a wave plate 53 is arranged in the display device of Example 9. FIG. 1 is a schematic diagram showing the configuration of a conventional display device; FIG.

Embodiments of a display device and an aerial image display method according to the present invention will be described below with reference to the drawings. Note that the drawings used in the following description are schematic, and the ratios of length, width, thickness, and the like are not necessarily the same as the actual ones, and can be changed as appropriate.

(First embodiment)
As shown in FIG. 1, the display device 1A of the first embodiment includes a first light source S1, a first retroreflection section 2A, a first light branching section 4, and a second retroreflection section 6. there is

The first light source S1 is, for example, an LED, but is not particularly limited. A plurality of first light sources S1 of the display device 1A of the first embodiment are arranged in parallel with the plate surface of the first display D1, and are provided so as to align the light emitting directions with each other. The number and relative arrangement of the first light sources S1 are not particularly limited.

In the present invention, the first retroreflector 2 is arranged at a position P2 on the first emission axis J1 indicating the emission direction E1 of the first light L1 emitted from the first light source S1.
The first retroreflective portion 2A of the first embodiment is arranged in the emitting direction E1 with reference to the first light source S1 on the first emitting axis J1. The first retroreflective portion 2A is preferably arranged near the first display D1 (that is, the position PS1 of the first light source S1) on the first emission axis J1. The first retroreflective portion 2A may be attached to the first display D1 on the emission direction E1 side of the first light source S1, and may be integrated with the first display D1.

The first retroreflective portion 2A has a known retroreflective structure. Examples of the retroreflective structure of the first retroreflective portion 2A include retroreflective structures 3A and 3B having a plurality of unit structures 10 each having at least one reflecting surface 12, as shown in FIGS. .

A surface 3a (that is, a surface on which light is incident) of the retroreflective structure 3A shown in FIG. 2 is formed flat. On the other hand, on the surface 3b of the retroreflective structure 3A, a plurality of triangular shapes forming the unit structures 10 when viewed from the side are formed adjacent to each other along the surface 3b.
The light L10a that has entered the surface 3a is transmitted through the surface 2a and enters the reflecting surface 12a of the unit structure 10 as light L10b. Light L10b is reflected by reflecting surface 12a and travels toward reflecting surface 12c of unit structure 10 as light L10c. In the retroreflective structure 3A, the internal angle formed by the reflective surfaces 12a and 12c of the unit structure 10 is set to a predetermined angle (ie approximately 90°). Therefore, the light L10c incident on the reflecting surface 12c is reflected by the reflecting surface 12c as light L10d in a direction parallel to the light L10b, and emitted from the surface 3a as reflected light L10e.
In FIG. 2, the refraction angles from the light 10a to the light 10b and the refraction angles from the light 10d to the light 10e bordering on the surface 3a are omitted.

On the surfaces 3a and 3b of the retroreflective structure 3B shown in FIG. 3, a plurality of semicircular shapes forming the unit structure 10 when viewed from the side are formed adjacent to each other along the surfaces 3a and 3b. That is, the retroreflective structure 3B is a structure in which a plurality of minute cylindrical bodies or spherical bodies are arranged so as to be adjacent to each other along one direction.
The light L10a incident on the surface 3a is transmitted through the surface 3a, refracted by the surface 3a at a refraction angle corresponding to its curvature, and travels toward the reflecting surface 12a of the unit structure 10 as light L10b. The light L10b incident on the reflecting surface 12a is reflected by the reflecting surface 12a and travels toward the surface 3a as reflected light L10d. Since the surface 3a and the reflecting surface 12a are formed to correspond to each other and form a sphere, the light L10d reflected by the reflecting surface 12a is refracted by the surface 3a in a direction parallel to the light L10a and reflected from the surface 3a. It is emitted as light L10e.

According to the first retroreflective portion 2A having the retroreflective structures 3A and 3B, the incident angle and the outgoing angle are equal, so the light incident on the first retroreflective portion 2A has the refractive index of the material of the retroreflective structure 3A. reflected in the same direction as the incident direction. The first retroreflective portion 2A is arranged so that the surface 3b side of the retroreflective structure 3A or the retroreflective structure 3B faces the first light source S1.

The material of the first retroreflective portion 2A allows the first light L1 to pass therethrough, and retroreflects light incident on the first retroreflective portion 2A from the side of the first light branching portion 4 (that is, the side opposite to the emission direction E1). If possible, it is not particularly limited. If the first light L1 is visible light, it is possible to transmit the first light L1 inside the retroreflective structures 3A and 3B with high efficiency. For example, optical glass, polycarbonate resin (PC), polymethyl methacrylate resin (PMMA) and the like can be mentioned. A reflecting material (not shown) is provided in contact with the surface 3b side, that is, the reflecting surfaces 12a and 12c. The reflective material is capable of transmitting the first light L1 in the emission direction E1 and reflecting light (for example, light L16, etc.) incident on the first retroreflective portion 2A in the direction opposite to the emission direction E1. A material is used, such as a dielectric material.

The structure and material of the first retroreflective portion 2 are not particularly limited as long as the light incident on the first retroreflective portion 2 can be reflected in the same direction as the incident direction.
For example, the first retroreflector 2 may be a full-corner cube, a cat-eye retroreflector, a combination of a lenticular lens and a reflector, or a lens in which single lenses are arranged in contact with each other vertically and horizontally (so-called fly-eye lens, fly-eye lens) and a reflector, a hologram that copies retroreflection performance, a spatial light modulator (SLM), an acousto-optic modulator (AOM), etc. Digital holograms, phase conjugate mirrors, etc., which are possible and programmed with retroreflection functions. As the full-corner cube, for example, a known prism type reflective sheet (see, for example, http://www.yao-sangyo.co.jp/sign/prism_4090.html, etc.) or crystal grade (registered trademark, for example, http:/ /www.carbide.co.jp/jp/viewer/file/product/4c74f1d8ac72dfc26d1e3587c0358529.pdfsurasshu4c74f1d8ac72dfc26d1e3587c0358529.pdf).

The first light branching part 4 reflects part of the first light L1 that has passed through the first retroreflecting part 2A toward the second retroreflecting part 6 as the first reflected light L2. At least part of the reflected first reflected light L2 is transmitted. The first light branching section 4 is arranged at a predetermined position closer to the user's viewing position than the first light source S1 and the first retroreflection section 2A. The first light branching section 4, which is, for example, a half mirror, reflects part of the first light L1 as described above, and at least part of the first reflected light L2 reflected by the first retroreflecting section 2A. It is not particularly limited as long as it can be permeated. As such a first light branching part 4, in addition to the half mirror, for example, a plate-shaped member made of acrylic or glass, a hollow body made of these materials and containing water in the hollow, punching metal, or the like can be used. Examples include a plate having rows of apertures, a wire grid film, a reflective polarizing film, and what is generally called a beam splitter.

The second retroreflective portion 6 is arranged at a position P6 on the second emission axis J2 that indicates the emission direction E2 of the first reflected light L2 reflected by the first light branching portion 4 . The position P6 of the second retroreflector 6 is in the emission direction E2, and considering the position PS1 of the first display D1, the position P2 of the first retroreflector 2A, and the position P4 of the first light splitter 4, It is appropriately set at a position where one reflected light L2 can be incident.

The second retroreflective portion 6 has a known retroreflective structure. That is, the structure and material of the second retroreflective portion 6 include the same structure and material as those of the first retroreflective portion 2 described above, but the light incident on the second retroreflective portion 6 is directed in the same direction as the incident direction. It is not particularly limited as long as it can be reflected to However, since the first reflected light L2 does not need to pass through the second retroreflector 6, for example, when the retroreflection structures 3A and 3B are employed, the reflecting material provided on the surface 3b side, that is, the reflecting surfaces 12a and 12c is In addition to the aforementioned dielectric materials, examples of the material include aluminum, gold, silver, and the like.

In the display device 1A of the first embodiment, part of the light L11 out of the first light L1 emitted from the first light source S1 is reflected by the first light splitter 4 as the reflected light L12 (first reflected light L2). reflected. The reflected light L12 enters the second retroreflection section 6, is reflected by the second retroreflection section 6 in the same direction as the incident direction, and enters the first light branching section 4 as the reflected light L13. It passes through the portion 4 and forms an aerial image I at a position Q1 symmetrical to the first light source S1 with respect to the plate surface (that is, the reflecting surface) of the first light branching portion 4 .
Further, the light L15 of the first light L1 is reflected by the first light branching portion 4, and then enters the first retroreflecting portion 2A as the reflected light L16 (first reflected light L2). It is reflected by the portion 2A in the same direction as the incident direction, passes through the first light branching portion 4, and reaches a position Q1 symmetrical to the first light source S1 with respect to the plate surface (that is, the reflecting surface) of the first light branching portion 4. to form an aerial image I.
For example, the light L18 (first light L1) emitted from the first light source S1 arranged at one end of the first display D1 is reflected by the first light splitter 4, and then the reflected light L19 ( It enters the first retroreflection portion 2A as the first reflected light L2), is reflected by the first retroreflection portion 2A in the same direction as the incident direction, passes through the first light branching portion 4, and passes through the first light branching portion 4. An aerial image I is formed at a position Q2 symmetrical to the first light source S1 with respect to the plate surface (that is, the reflecting surface).

According to the display device 1A of the first embodiment described above, in addition to the certain area Z1 in the space A (that is, the space where the user is present with respect to the first light branching section 4), the conventional display device The aerial image I can be observed even in the area Z2 where the image could not be observed in . Therefore, the user can observe the aerial image I displayed in the areas Z1 and Z2 from the observation direction E0 on the side opposite to the first light source S1 with respect to the first light branching section 4 . This makes it possible to increase the angle θ1A at which the aerial image I can be seen on the display device 1A. Further, as can be seen from FIG. 1, substantially all of the first light L1 emitted from the first light source S1 contributes to the formation of the image I regardless of the position of the first light source S1 on the first display D1. Therefore, the brightness of the aerial image I can be improved.

(Second embodiment)
Next, a display device 1B according to a second embodiment of the invention will be described. In addition, in the components of the display device 1B of the second embodiment shown in FIG. 4, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 4, the display device 1B includes a first light source S1, a first retroreflective portion 2A, a first light branching portion 4 arranged to face the first retroreflective portion 2A, and a first A wave plate 21 , a second wave plate 22 , and a first polarization splitter 25 are provided.
Further, the display device 1B is configured such that the first reflected light L2 is incident on the first retroreflection portion 2A.

The arrangement of the first retroreflector 2A is not particularly limited as long as the user can see the aerial image I formed by the first retroreflector 2A and the first light source S1 (that is, directly transmitted light) as one. not. Specifically, if the distance between the user's eye position and the aerial image I (that is, the observation distance) is V, and the distance between the position PS1 of the light source S1 and the position P2 of the first retroreflector 2A is T, then It is preferred that T<(V/50).

The first wave plate 21 is arranged between the first light source S1 and the first retroreflection section 2 on the first emission axis J1. The second wave plate 22 is arranged in the emission direction E1 of the first light L1 with reference to the first retroreflector on the first emission axis J1.
The first wave plate 21 and the second wave plate 22 are so-called λ/4 plates configured to give a phase difference of (π/2) in the electric field oscillation direction of light incident thereon.

The first polarization splitter 25 is arranged between the first light source S1 and the first wave plate 21 on the first emission axis J1. Therefore, in the display device 1B, along the emission direction E1 of the first light L1, the first display D1 including the first light source S, the first polarization splitter 25, the first wavelength plate 21, the first retroreflector 2A, The second wavelength plate 22 and the first optical splitter 4 are arranged to face each other. Of these, the first display D1, the first polarization splitter 25, the first wave plate 21, the first retroreflector 2A, and the second wave plate 22 are preferably very close to each other and are in contact with each other. It may be integrated.
The first polarization splitter 25 is configured to be able to transmit P-polarized light and reflect S-polarized light, and is, for example, a reflective polarization beam splitter.

In the display device 1B of the second embodiment, of the first light L1 emitted from the first light source S, only the P-polarized first light L1 passes through the first polarization splitter 25 and travels along the emission direction E1. It is emitted, passes through the first wave plate 21, the first retroreflector 2, and the second wave plate 22 in this order, becomes the S-polarized first light L1, and is emitted. A portion of the S-polarized first light L1 emitted from the second wave plate 22 is reflected by the first light splitter 4 as the first reflected light L2. The S-polarized first reflected light L2 is transmitted through the second wavelength plate 22, enters the second retroreflection section 6, is reflected by the second retroreflection section 6 in the same direction as the incident direction, and is reflected by the second wavelength plate again. 22 and enters the first light branching portion 4 as the P-polarized reflected light L3, passes through the first light branching portion 4, and is directed to the plate surface (that is, the reflecting surface) of the first light branching portion 4. to form an aerial image I at a position Q1 symmetrical to the first light source S1.

According to the display device 1B of the second embodiment described above, the user can observe the aerial image I from the observation direction E0 on the side opposite to the first light source S1 with respect to the first light splitter 4. FIG. As a result, the angle θ1B at which the aerial image I can be seen in the display device 1B of the second embodiment extends over the entire area of the first light source S1 arranged on the first display D1, and the angle θ1B can be increased. . Further, as can be seen from FIG. 4, regardless of the position of the first light source S1 on the first display D1, substantially all of the P-polarized first light L1 emitted from the first light source S1 is used to form the aerial image I. can contribute to

Further, according to the display device 1B of the second embodiment, the first retroreflective portion 2 is provided in the emission direction E1 of the first light L1 with respect to the first light source S1 and the first display D1, and the first light branching portion As 4, a reflective polarizing film, a polarizing plate, a half mirror provided with a polarizing film, or the like is used to block direct transmitted light by the first light branching unit 4, so that the user can easily see the first light source S and the first light source S. Display D1 (ie direct transmitted light) is not visible. Therefore, it is possible to prevent deterioration of the visibility of the aerial image I due to the mixture of the aerial image I and the first light source S1.

Further, according to the display device 1B of the second embodiment, the second retroreflection section 6 is omitted, and along the emission direction E1 of the first light L1, the first light source S1, the first polarization splitter 25, the first The wave plate 21, the first retroreflector 2A, the second wave plate 22, and the first light splitter 4 can be arranged, and the overall device can be made compact and space-saving.

(Third embodiment)
Next, a display device 1C according to a third embodiment of the invention will be described. In addition, in the components of the display device 1C of the third embodiment shown in FIG. 5, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 5, the display device 1C includes a first light source S1, a first retroreflective portion 2A, a first light branching portion 4, a first wave plate 21, a second wave plate 22, and a first A polarization splitter 25, a second light source S2, a second retroreflector 7, a second light splitter 5, a third wave plate 23, a fourth wave plate 24, a second polarization splitter 26, It has

The second light source S2 is, for example, an LED like the first light source S1, but is not particularly limited. A plurality of second light sources S2 of the display device 1C of the third embodiment are arranged in parallel with the plate surface of the second display D2, and the light emitting directions are aligned with each other. In addition, the number of the second light sources S2 is not particularly limited. However, the second light source S2 is arranged so as to be able to emit the second light L21 in a direction E3 opposite to the emission direction E2 of the first reflected light L2 (hereinafter referred to as emission direction E3).

The second retroreflection part 7 is arranged at a position P7 on the third emission axis J3 that indicates the emission direction E3 of the second light L21, and is capable of retroreflecting the first reflected light L2 and at least part of the second light L21. is configured to be permeable. The structure and material of the second retroreflective portion 7 may be the same structure and material as those of the first retroreflective portion 2 described above.

The second light branching unit 5 transmits part of the second light L21 that has passed through the second retroreflection unit 7, and converts at least part of the second light L21 that has passed through the second retroreflection unit 7 into second reflected light. Reflect as L22.

The third wave plate 23 is arranged between the second light source S2 and the second retroreflector 7 on the third emission axis J3. The fourth wave plate 24 is arranged at a position in the emission direction E3 of the second light L21 with respect to the second retroreflector 7 on the third emission axis J3.
The third wave plate 23 and the fourth wave plate 24, similarly to the first wave plate 21 and the second wave plate 22, are arranged so as to give a phase difference of (π/2) in the electric field oscillation direction of light incident thereon. It is a so-called λ/4 plate.

The second polarization splitter 26 is arranged between the second light source S2 and the third wave plate 23 on the third emission axis J3. Therefore, in the display device 1C, along the emission direction E3 of the second light L21, the second display D2 including the second light source S2, the second polarization splitter 26, the third wave plate 23, the second retroreflector 7, A fourth wavelength plate 24 and a second light splitter 5 are appropriately arranged. Of these, the second display D2, the second polarization splitter 26, the third wave plate 23, the second retroreflector 7, and the fourth wave plate 24 are preferably very close to each other and are in contact with each other. It may be integrated.
The second polarization splitter 26 is configured to be able to reflect P-polarized light and transmit S-polarized light, and is, for example, a reflective polarization beam splitter.

As can be seen by referring to FIG. 5, the display device 1C of the third embodiment is the display device 1B of the second embodiment, in which the first display D1 including the first light source S1, the first polarization splitter 25, the first wavelength The relative positions of the configuration including the plate 21, the first retroreflector 2A and the second wave plate 22 and the first light branching unit 4 are the first display D1 and the first retroreflector in the display device 1A of the first embodiment. The relative positions of the portion 2A and the first optical branching portion 4 are the same, and similar structures are arranged so as to face these structures.

In the display device 1C of the third embodiment, of the first light L1 emitted from the first light source S1, only the P-polarized first light L1 is transmitted through the first polarization splitter 25 and along the emission direction E1. It is emitted, passes through the first wave plate 21, the first retroreflector 2, and the second wave plate 22 in this order, becomes the S-polarized first light L1, and is emitted. A portion of the S-polarized first light L1 emitted from the second wave plate 22 is reflected by the first light splitter 4 as the first reflected light L2. The S-polarized first reflected light L2 is transmitted through the second wavelength plate 22, enters the second retroreflection section 6, is reflected by the second retroreflection section 6 in the same direction as the incident direction, and is reflected by the second wavelength plate again. 22 and enters the first light branching portion 4 as the P-polarized reflected light L3, passes through the first light branching portion 4, and is directed to the plate surface (that is, the reflecting surface) of the first light branching portion 4. to form an aerial image I1 at a position Q1 symmetrical to the first light source S1.

On the other hand, of the second light L21 emitted from the second light source S2, only the S-polarized second light L21 is transmitted through the second polarization splitter 26 and emitted along the emission direction E3. , the second retroreflector 7, and the fourth wave plate 24 in this order to become the P-polarized first light L21 and exit. A portion of the P-polarized first light L1 emitted from the fourth wave plate 24 is reflected by the second light splitter 5 as the first reflected light L2. The P-polarized first reflected light L2 is transmitted through the fourth wavelength plate 24, enters the second retroreflection section 7, is reflected by the second retroreflection section 7 in the same direction as the incident direction, and is reflected again by the fourth wavelength plate. 24 and enters the second light branching portion 5 as S-polarized reflected light L3, and also passes through the second light branching portion 5 and is directed to the plate surface (that is, the reflecting surface) of the second light branching portion 5. to form an aerial image I2 at a position Q10 symmetrical to the second light source S2.

According to the display device 1C of the third embodiment described above, the user can see the aerial image I1 (for example, the character image "A") can be observed. On the other hand, the user can observe the aerial image I2 (for example, the character image “B”) from the observation direction E10 on the side opposite to the second light source S2 with respect to the second light splitter 5 . As described above, according to the display device 1C of the third embodiment, multi-viewing of the aerial images I1 and I2 can be achieved.
In the above-described arrangement in which the polarization directions of the transmitted light in the first light branching unit 4 and the second light branching unit 5 are orthogonal, the second light source S2 and the second display D2 are behind the aerial image I1 from the observation direction E0. (ie, directly transmitted light) can be observed through the first light splitter 4, and from the viewing direction E10, the first light source S1 and the first display D1 (ie, directly transmitted light) are placed behind the aerial image I10 in the second light splitter. It can be observed through part 5. That is, a two-layered multi-viewing of the aerial image and the direct transmitted light serving as the background is achieved.
On the other hand, when the first light branching section 4 and the second light branching section 5 are arranged so that the polarization directions of the transmitted light are parallel, for example, the second light branching section 5 is arranged so that only the P-polarized component is transmitted. and correspondingly, when the second polarization splitter 26 is also arranged so that only the P-polarized component is transmitted, the first light source S1 and the first display D1 (that is, directly transmitted light) and the second light source S2 and the second display D2 (that is, direct transmitted light) are not observed, only the aerial image I1 is observed in the observation direction E1, and only the aerial image I10 is observed in the observation direction E10 for multi-viewing. .
Although FIG. 5 shows multi-viewing in two directions, multi-viewing in three or more directions is possible by installing the display device 1B so as to face each viewing direction.
The angles at which the aerial images I1 and I2 are visible cover the entire area of the first light source S1 arranged on the first display D1 and the entire area of the second light source S2 arranged on the second display D2. You can make it bigger. Further, regardless of the position of the first light source S1 on the first display D1 or the position of the second light source S2 on the second display D2, the P-polarized first light L1 emitted from the first light source S1 and the second light source S2 Substantially all of the emitted S-polarized second light L21 can contribute to the formation of the aerial images I1 and I2.

Further, according to the display device 1C of the third embodiment, by using a reflective polarizing film, a polarizing plate, or a half mirror provided with a polarizing film as the first light branching unit 4 and the second light branching unit 5, Since the direct transmitted light is blocked by the first light splitter 4 and the second light splitter 5, the user cannot see the first light source S and the first display D1 (that is, the directly transmitted light). Therefore, it is possible to prevent deterioration of the visibility of the aerial image I due to the mixture of the aerial image I and the first light source S1 or the second light source S2.

In a display device 1D that is a modification of the display device 1C of the third embodiment, as shown in FIG. A structure including a wave plate 21 and a second wave plate 22, a first polarization splitter 25, a second light source S2, a second retroreflector 7, a third wave plate 23, a fourth wave plate 24, a second A configuration including the polarization splitter 26 and a configuration in which the polarization splitter 26 is placed close to each other. Therefore, in the display device 1D, the second light splitter 5 is omitted.

According to the display device 1D, which is a modification of the third embodiment, the angle at which the aerial image I can be seen is the first light source S1 arranged on the first display D1 or the second light source S1 arranged on the second display D2. It will span the entire area of S2 and can be large. In addition, by installing the first polarization splitter 25 so that the direct light of the first display D1 passes through the first light splitter 4, the user can From some opposite direction E0, a directly lit background (eg, the letter "U") can be seen behind the aerial image I3 (eg, the letter "O"). Thus, according to the display device 1D, which is a modified example of the third embodiment, it is possible to achieve two layers of the aerial image I and the direct image.

(Fourth embodiment)
Next, a display device 1E according to a fourth embodiment of the invention will be described. In addition, in the components of the display device 1E of the fourth embodiment shown in FIG. 7, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 7, the display device 1E includes a first light source S1, a first retroreflection section 2, a first light branching section 4, a second light source S2, and a second retroreflection section 7. ing. The display device 1E has the configuration of the display device 1A, in which the second retroreflective portion 7 is provided at the position of the second retroreflective portion 6, and the second display D2 is arranged in the emission direction E2 of the second reflected light L2. .

In the display device 1E of the fourth embodiment, part of the first light L1 emitted from the first light source S1 is reflected by the first light splitter 4 as the first reflected light L2. The first reflected light L2 enters the second retroreflection section 6, is reflected by the second retroreflection section 6 in the same direction as the incident direction, and enters the first light branching section 4 as reflected light L3. It passes through the light branching portion 4 and forms an aerial image I1 at a position Q1 symmetrical to the first light source S1 with respect to the plate surface (that is, the reflecting surface) of the first light branching portion 4 .
A portion of the second light L21 emitted from the second light source S2 is also reflected by the first light splitter 4 as the first reflected light L2. The first reflected light L2 enters the second retroreflection section 6, is reflected by the second retroreflection section 6 in the same direction as the incident direction, and enters the first light branching section 4 as reflected light L3. It passes through the light branching portion 4 and forms an aerial image I2 at a position Q10 symmetrical to the second light source S2 with respect to the plate surface (that is, the reflecting surface) of the first light branching portion 4 .

According to the display device 1E of the fourth embodiment described above, the user can see the aerial image I1 and the display D2 from the direction E0 on the side opposite to the first light source S1 with respect to the first light branching unit 4. Both of the second light sources S2 (ie direct transmitted light) are visible. On the other hand, the user can see both the aerial image I2 and the first light source S1 (that is, directly transmitted light) of the display D1 from the observation direction E10 on the side opposite to the second light source S2 with respect to the second light splitter 5. can see As described above, according to the display device 1C of the third embodiment, it is possible to achieve multi-viewing by combining the aerial image I and the displays D1 and D2 (that is, the light sources S1 and S2).
The angle θ1E at which the aerial images I1 and I2 are visible extends over the entire regions of the first light sources S1 and S2 arranged on the first displays D1 and D2, respectively, and becomes large. Further, regardless of the position of the first light source S1 on the first display D1 or the position of the second light source S2 on the second display D2, the first light L1 emitted from the first light source S1 and the light emitted from the second light source S2 Substantially all of the second light L21 can contribute to the formation of the aerial images I1 and I2.

(Fifth embodiment)
Next, a display device 1F according to a fifth embodiment of the invention will be described. In addition, in the components of the display device 1F of the fifth embodiment shown in FIG. 8, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 8, the display device 1F includes a first light source S1, a first retroreflection section 2B, a first light branching section 4, and a second retroreflection section 6. As shown in FIG.

In the display device 1F, the first retroreflector 2B is located opposite the emission direction E1 with respect to the first light source S1 on the first emission axis J1 indicating the emission direction E1 of the first light L1 emitted from the first light source S1. placed on the side.
The second retroreflective portion 6 is arranged so as to connect the outer peripheral edge of the first retroreflective portion 2</b>B and the outer peripheral edge of the first light branching portion 4 .
However, since it is not necessary to transmit the first light L1 or the first reflected light L2 in the first retroreflection part 2B, for example, when the retroreflection structures 3A and 3B are adopted, the surface 3b side, that is, the reflection surfaces 12a and 12c Examples of the reflective material to be provided include aluminum, gold, silver, etc., in addition to the aforementioned dielectric material. That is, the first retroreflective portion 2B and the second retroreflective portion 6 may have similar retroreflective structures.

In the arrangement described above, the first light source S1 is arranged in the space X surrounded by the first retroreflecting portion 2B, the first light branching portion 4, and the second retroreflecting portion 6. As shown in FIG.
In the third display D3 having the first light source S1, that is, the position PS1 of the first light source S1, the non-placement portion NS of the first light source S1 can transmit the first light and the first reflected light L2. Examples of such a third display D3 include what is called a transparent display or a see-through display. Specifically, for example, a liquid crystal display with transparent pixels without a color filter, a part of which is made transparent with an organic EL display, etc. A panel in which the non-arrangement portion NS can be seen through, or a panel (so-called ribbon LED, etc.) made up of a plurality of LEDs arranged in a stripe pattern at intervals can be used.

In the display device 1F of the fifth embodiment, part of the first light L1 emitted from the first light source S1 is reflected by the first light splitter 4 as the first reflected light L2. The first reflected light L2 enters the first retroreflecting portion 2B, is reflected by the first retroreflecting portion 2B in the same direction as the incident direction, partially transmits through the non-arranged portion NS of the third display D3, and reaches the third display D3. While entering one light branching part 4, it passes through the first light branching part 4, and is in the air at a position Q1 symmetrical to the first light source S1 with respect to the plate surface (that is, the reflecting surface) of the first light branching part 4. An image I is formed.
Further, of the first light L1, the first light L18 that has entered the first light branching section 4 at a relatively small angle of incidence is reflected by the first light branching section 4, and then reflected light L28 (first reflected light L2) is incident on the second retroreflective portion 6, reflected by the second retroreflective portion 6 in the same direction as the incident direction, transmitted through the first light branching portion 4, and plate surface of the first light branching portion 4 (that is, , reflecting surface), an aerial image I is formed at a position Q1 symmetrical to the first light source S1.

According to the display device 1F of the fifth embodiment described above, the user can observe the aerial image I from a certain direction E0 on the side opposite to the first light source S1 with respect to the first light splitter 4. FIG. The angle at which the aerial image I can be seen in the display device 1F extends over substantially the entire plate surface of the first light branching unit 4, so it can be made larger than in conventional display devices and the like. Further, as can be seen from FIG. 8, substantially all of the first light L1 emitted from the first light source S1 contributes to the formation of the aerial image I regardless of the position of the first light source S1 on the first display D1. Therefore, the brightness of the aerial image I can be improved.

(Sixth embodiment)
Next, a display device 1G according to a sixth embodiment of the invention will be described. In addition, in the components of the display device 1G of the sixth embodiment shown in FIG. 9, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 9, the display device 1G includes a fourth display D4 having a first light source S1 and a first retroreflective portion 2C, a first light branching portion 4, and a second retroreflective portion 6. I have.
Further, the display device 1G is configured such that the first reflected light L2 is incident on the first retroreflection portion 2C.

In the display device 1G, the fourth display D4 is arranged on the surface 35a of the substrate 35, the first light source S1 and the first light source S1 arranged with a space therebetween (that is, the first light source S1 is not arranged). A first retroreflective portion 2C is arranged in the portion NS). With such a configuration, the first retroreflective portion 2C is arranged at a position P2 on the first emission axis J1 that indicates the emission direction E1 of the first light source S1 and the first light L1 emitted from the first light source S1. It is That is, at the same positions PS1 and P2, as shown in FIG. 10, the plurality of light sources S1 and the first retroreflectors 2C are space-divided.
In addition, since it is not necessary to transmit the first light L1 and the first reflected light L2 in the first retroreflection part 2C, for example, when the retroreflection structures 3A and 3B are adopted, the surface 3b side, that is, the reflection surfaces 12a and 12c Examples of the reflective material to be provided include aluminum, gold, silver, etc., in addition to the aforementioned dielectric material.

In the display device 1G of the sixth embodiment, as shown in FIG. 9, part of the first light L1 emitted from the first light source S1 is reflected by the first light splitter 4 as the first reflected light L2. . The first reflected light L2 incident on the first retroreflecting portion 2C is reflected by the first retroreflecting portion 2C in the same direction as the incident direction, passes through the first light branching portion 4, and reaches the plate of the first light branching portion 4. An aerial image I is formed at a position Q1 symmetrical to the first light source S1 with respect to a surface (that is, a reflecting surface).
Further, of the first light L1, the first light L18 that has entered the first light branching section 4 at a relatively small angle of incidence is reflected by the first light branching section 4, and then reflected light L28 (first reflected light L2) is incident on the second retroreflective portion 6, reflected by the second retroreflective portion 6 in the same direction as the incident direction, transmitted through the first light branching portion 4, and plate surface of the first light branching portion 4 (that is, , reflecting surface), an aerial image I is formed at a position Q1 symmetrical to the first light source S1.

According to the display device 1G of the sixth embodiment described above, the user can observe the aerial image I from a certain direction E0 on the side opposite to the first light source S1 with respect to the first light splitter 4. FIG. The angle at which the aerial image I can be seen in the display device 1G extends over substantially the entire plate surface of the first light branching unit 4, so it can be made larger than in conventional display devices and the like. Further, as can be seen from FIG. 9, substantially all of the first light L1 emitted from the first light source S1 contributes to the formation of the aerial image I regardless of the position of the first light source S1 on the fourth display D4. Therefore, the brightness of the aerial image I can be improved.

In the display device 1H, which is a first modified example of the display device 1G of the sixth embodiment, as shown in FIG. It is arranged so as to be inclined at approximately 45° with respect to the surface of the portion 2C).

According to the display device 1H which is the first modified example of the sixth embodiment, it is possible to obtain the same effect as the display device 1G of the sixth embodiment, and furthermore, the aerial image I is displayed on the surface of the fourth display D4. , can be formed in substantially orthogonal directions.
The angle formed by the surfaces of the first light branching unit 4 and the fourth display D4 is not limited to approximately 45°, and can be set to any angle. It is formed.

A display device 1K, which is a second modification of the display device 1G of the sixth embodiment, includes a polarizing plate 40 in addition to the configuration of the display device 1H, as shown in FIG. However, the first retroreflector 2C maintains a relative relationship in which the space is divided with the first light source S1 in the horizontal direction, and the emission direction of the first light L1 is based on the first light source S1 on the first emission axis J1. It is located at position P2 of E1. The polarizing plate 40 is arranged between the first light source S1 on the first emission axis J1 and the first retroreflective portion 2C.

In the display device 1K, which is the second modified example of the sixth embodiment, only the predetermined polarized light of the first light L1 emitted from the first light source S1 is transmitted through the polarizing plate 40, and the first light transmitted through the polarizing plate 40 is The light L1 is reflected by the first light splitter 4 as the first reflected light L2. The first reflected light L2 incident on the first retroreflecting portion 2C is reflected by the first retroreflecting portion 2C in the same direction as the incident direction, passes through the first light branching portion 4, and reaches the plate of the first light branching portion 4. An aerial image I is formed at a position Q1 symmetrical to the first light source S1 with respect to a surface (that is, a reflecting surface).

According to the display device 1K which is the second modified example of the sixth embodiment, it is possible to obtain the same effect as the display device 1G which is the first modified example of the sixth embodiment. Further, according to the display device 1K which is the second modified example of the sixth embodiment, the polarizing plate 40 is provided, the reflective polarizing film is provided as the first light branching unit 4, the polarizing plate and the half mirror are provided with the polarizing film. Since the direct transmitted light is blocked by the first light splitter 4 by using an object or the like, the user cannot see the first light source S1 (that is, the directly transmitted light) and the fourth display D4. Therefore, it is possible to prevent deterioration of the visibility of the aerial image I due to the mixture of the aerial image I and the first light source S1.
In addition, also in the display device 1G of the sixth embodiment shown in FIG. 9, the first retroreflective portion 2C is positioned at the position P2 in the emission direction E1 of the first light L1 with reference to the first light source S1 on the first emission axis J1. If the polarizing plate 40 is arranged between the first light source S1 and the first retroreflection portion 2C on the first emission axis J1, the direct transmitted light is blocked as described above, and only the aerial image I is visible. Observed.

(Seventh embodiment)
Next, a display device 1V according to a seventh embodiment of the invention will be described. In addition, in the constituent elements of the display device 1V of the seventh embodiment shown in FIG. 13, the constituent elements that are the same as the constituent elements of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 13, the display device 1V includes a first display D1 having a first light source S1, a first light splitter 4, and a first retroreflector 2A.

In the display device 1V, the first retroreflective portion 2A is arranged at a position on the second reflection axis J2 that indicates the emission direction E2 of the first reflected light L2.
Further, the first light branching portion 4 protrudes toward the side opposite to the side on which the first light source S1 and the first retroreflecting portion 2A are arranged with respect to the first light branching portion 4 as it goes from the outer peripheral edge toward the center. curved in shape.

According to the display device 1V of the seventh embodiment described above, similarly to the display device 1A of the first embodiment, the user can enter the space A (that is, the space where the user is with respect to the first light branching section 4). , the aerial image I can be observed. Further, according to the display device 1V of the seventh embodiment, the second retroreflector 6 is not required, and the configuration of the device can be simplified as compared with the display device 1A of the first embodiment. Furthermore, in the display device 1V of the seventh embodiment, it becomes easier to arrange the aerial image I substantially perpendicular to the tangent line passing through the vertex of the curved first light branching portion 4 . This prevents the first light source S1 and the virtual image of the first light source S1 from being seen when the first light source S1 and the first retroreflector 2A are removed from the observation direction E0 and the aerial image I is viewed from the observation direction E0. , the aerial image I can be easily recognized visually.

(Eighth embodiment)
Next, a display device 1W according to an eighth embodiment of the invention will be described. In addition, in the components of the display device 1W of the eighth embodiment shown in FIG. 14, the same components as the components of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 14, the display device 1W includes a first display D1 having a first light source S1, a first wavelength plate 21, a first retroreflector 2A, a first reflector 50A, and a first light It has a branching portion 4 and a second reflector 50B.

In the display device 1W, the first wave plate 21 extends from the side end portion (one side portion of the first light source) e1 of the first display D1 along the first emission axis J1 indicating the emission direction E1 of the first light L1. extended. The first retroreflective portion 2A is provided along the first wave plate 21 on the side of the first wave plate 21 opposite to the side facing the first display D1. The first reflector 50A extends along the first emission axis J1 from the side edge portion (the other side portion of the first light source) e2 of the first display D1. The first reflector 50A corresponds to, for example, a known total reflection mirror, but is not particularly limited as long as it can reflect the first light L1. The first optical splitter 4 is arranged to connect the tip e3 of the first wave plate 21 and the tip e4 of the first reflector 50A.

The second reflecting plate 50B extends in the same direction as the extending direction of the first reflecting plate 50A across the first light branching portion 4 from the tip e4 of the first reflecting plate 50A. are flush with each other. Also, the second reflector 50B reflects at least a portion of the first reflected light L2 reflected by the first retroreflection portion 2A and transmits the rest. The second reflector 50B is, for example, a known half mirror, but is not particularly limited as long as it can reflect the first reflected light L2. The second reflector 50B may be a total reflection mirror that reflects all the first reflected light L2 reflected by the first retroreflector 2A. Moreover, the second reflecting plate 50B only needs to reflect at least part of the first reflected light L2, and may be a transparent plate (such as a desk mat made of glass). For example, when a desk mat is used as the second reflector 50B, the aerial image I appears to float above the wood grain of the desk.

In the display device 1W of the eighth embodiment described above, of the first light L1 emitted from each of the first light sources S1 of the first display D1, the light directed toward the first reflector 50A is the first reflector 50A. , and further reflected toward the first wavelength plate 21 by the first light branching section 4 made up of a reflective polarizing plate or the like. One of the P-polarized light and the S-polarized light of the first light L1 is transmitted through the first wavelength plate 21, retroreflected as the first reflected light L2 by the first retroreflector 2A, and transmitted through the first light splitter 4. . The first reflected light L2 transmitted through the first light branching portion 4 is reflected as retroreflected light (reflected light) L13 by the second reflector 50B, and the first reflected light L2 is directly emitted from the first retroreflecting portion 2A. Together, an aerial image I is formed. Further, as shown in FIG. 14, a virtual image of the first display D1 is generated on the opposite side of the first display D1 with the first reflectors 50A and 50B interposed therebetween.

Therefore, according to the display device 1W of the eighth embodiment, similarly to the display device 1A of the first embodiment, the user can enter the space A (that is, the space where the user is with respect to the first light branching section 4). An aerial image I can be observed. For example, if the first reflecting plate 50A and the second reflecting plate 50B are placed on a base such as a table, an aerial image I that rises substantially vertically from the above-described base can be obtained, making it easier to observe the aerial image I. If a half mirror is used as the second reflector 50B and a transparent base is used, the aerial image I and the virtual image can be observed at the same time.

(Ninth embodiment)
Next, a display device 1P of a ninth embodiment according to the invention will be described. In addition, in the constituent elements of the display device 1P of the ninth embodiment shown in FIG. 15, the constituent elements that are the same as the constituent elements of the display device 1A of the first embodiment shown in FIG. The explanation is omitted.

As shown in FIG. 15, the display device 1P includes a first light source S1, a first light branching section 4A, a second light branching section 4B, and a first retroreflection section 2A.

In the display device 1P, the first light branching section 4A and the second light branching section 4B are arranged so as to face each other with the first light source S1 interposed therebetween. In other words, the first light source S1 is arranged between the first light branching section 4A and the second light branching section 4B which are arranged to face each other. An emission portion (not shown) of the first light source S1 is directed to a space formed between the first light branching portion 4A and the second light branching portion 4B. The first light branching portion 4A and the second light branching portion 4B reflect at least part of the first light L1 as the first reflected light L2, and reflect at least part of the first reflected light L2. A first retroreflective portion 2A is provided on the surface of the second light branching portion (one light branching portion) 4B opposite to the surface (side) facing the first light branching portion 4A.

In the display device 1P of the ninth embodiment, the first light L1 emitted from the first light source S1 passes through the space formed between the first light branching portion 4A and the second light branching portion 4B, It hits the portion 4A or the second light branching portion 4B and passes through. The first light L1 is returned to the first light source S1 side as the retroreflected light 13 in the direction along the surface of the second light branching part 4B when the first retroreflection part 2A is irradiated. As a result, a plurality of aerial images I are formed in a direction substantially orthogonal to the surface of the first light branching portion 1A at positions facing the first light source S1 across the first light branching portion 1A.

A virtual image is formed on a virtual line L113 extending the light L111 reflected by the second light branching portion 4B toward the first retroreflecting portion 2A. That is, a plurality of virtual images are formed at positions facing the first light source S1 with the second light branching portion 1B interposed therebetween.

Therefore, according to the display device 1P of the ninth embodiment, similarly to the display device 1A of the first embodiment, the user can set the space A (that is, the first light branching section 4 to the first light source S1). A plurality of aerial images I can be observed in the space on the side opposite to the side where the object is located. As a result, a multi-stage aerial image I can be easily formed using the display device 1P, and the range of application and development of the display device 1P is widened.

FIG. 16 shows a display device 1Q that is a first modification of the display device 1P of the ninth embodiment. In the display device 1P, the display device 1Q has a second light source S2 spaced apart from the first light source S1 in the space formed between the first light branching portion 4A and the second light branching portion 4B. is. The output portion (not shown) of the second light source S2 is directed toward the space formed between the first light branching portion 4A and the second light branching portion 4B, and the direction in which the output portion of the second light source S2 is directed. is directed in the opposite direction. In other words, the display device 1Q connects the display device 1N to the first light source S1 side of the display device 1P while reversing the direction perpendicular to the surfaces of the first light branching portion 4A and the second light branching portion 4B. It is a thing.

According to the display device 1Q of the first modification of the display device 1P of the ninth embodiment, by using the first light source S1 and the second light source S2, the aerial image I is generated from each light source, and the aerial image I You can easily increase the number. The number of aerial images I can be further increased by utilizing the virtual images of the respective light sources.

In the display device 1P, the first retroreflective portion 2A is in contact with the second light branching portion 4B, but as in the display device 1P' shown in FIG. may be arranged at a predetermined interval with respect to In this manner, the display device 1P has a degree of freedom in arranging the components. Also, in the display device 1P, both sides of one transparent acrylic plate or transparent glass plate can be used as 4A and 4B. For example, if an LED is placed on the sash of the glass window and a curtain of retroreflective sheet is attached to the glass window, the multiplexed aerial image I can be observed from the outside. Furthermore, by arranging another retroreflector at a place where observation of the aerial image I is not hindered on the first light branching section 4A side, it becomes possible to form the aerial image I for the light ray L111 as well.

FIG. 18 shows a display device 1R that is a second modification of the display device 1P of the ninth embodiment. In the display device 1R, the surface of the first light branching portion 4A of the display device 1N is inclined with respect to the direction along the surface of the second light branching portion 4B. In the configuration example shown in FIG. 18, the first light branching portion 4A is separated from the second light branching portion 4B as it progresses from the left side to the right side of the paper surface.

According to the display device 1R of the second modification of the display device 1P of the ninth embodiment, a plurality of real images and virtual images of the first light source S1 are projected on the surfaces of the first light branching portion 4A and the second light branching portion 4B. It is formed on an imaginary circle centered on the imaginary intersection where the extension lines intersect. Although the display device 1R is an example, the position of the aerial image I, that is, the plurality of first light sources S1 can be adjusted by adjusting the opposing arrangement and angle of the first light branching portion 4A and the second light branching portion 4B. The positions at which the real and virtual images are formed can be easily changed. In addition, the display device 1P of the ninth embodiment may be provided with an adjustment section capable of adjusting the arrangement and angle of the first light branching section 4A and the second light branching section 4B.

Further, although not shown, the display device 1P and the display devices 1Q, 1P', and 1R of its modified examples use a light source (for example, a point light source, an LED, or the like) capable of emitting the spot-shaped first light L1. Since a plurality of aerial images I can be formed, it can be applied as a kaleidoscope. Conventionally, in order to realize a kaleidoscope for multiple people, it was necessary to enlarge the kaleidoscope itself to the extent that multiple people can look at it at the same time. However, by arranging the aerial image I like a kaleidoscope pattern using the display device 1P or the like, a kaleidoscope pattern can be formed in the air and can be observed by a plurality of people at the same time.

(Tenth embodiment)
Next, a display device 1T according to a tenth embodiment of the invention will be described. In addition, in the components of the display device 1T of the tenth embodiment shown in FIGS. 20 to 23, the same components as those of the display device 1A of the first embodiment shown in FIG. and description thereof is omitted.
FIG. 19 shows a known display device CT.

The display device 1T of the tenth embodiment includes a backlight 55 having a plurality of first light sources S1, a first liquid crystal panel 51, a first polarizing plate 40A, a first light branching section 4, and a first retroreflection section. 2A and.

In the display device 1T, the backlight 55 is for illuminating the first liquid crystal panel 51 and the second liquid crystal panel 52 from behind the first emission axis J1 indicating the emission direction E1 of the first light L1. In the backlight 55, the first light source S1 is arranged with the emitting portion directed toward the first polarizing plate 40A. However, the number of liquid crystal panels stacked along the first emission axis J1 is not limited to two, and may be three or more. Further, a retardation film may be included between the liquid crystal panels laminated along the first emission axis J1.

The first liquid crystal panel 51 is arranged at a position on the first emission axis J1. The first polarizing plate 40A is arranged between the first display D1 and the first liquid crystal panel 51 on the first output axis J1.

The first light splitter 4 reflects at least part of the first light L1 as the first reflected light L2, and transmits at least part of the retroreflected light L13 retroreflected by the first retroreflector 2A. The first retroreflective portion 2A is arranged at a position on the second emission axis J2 that indicates the emission direction E2 of the first reflected light L2.

As shown in FIG. 19, in the conventional display device CT, in addition to the configuration described above, a second liquid crystal panel 52 is arranged between the first polarizing plate 40A on the first emission axis J1 and the first liquid crystal panel 51. A second polarizing plate 40B is arranged in front of the first liquid crystal panel 51 on the first output axis J1. The second liquid crystal panel 52 is a so-called rear liquid crystal panel. In the display device CT, the first polarizing plate 21 and the second polarizing plate 22 are arranged on the backlight 55 side with respect to the first light branching section 4 . That is, the backlight 55, the first polarizing plate 21, the first liquid crystal panel 51, the second liquid crystal panel 52, and the second polarizing plate 22 constitute multilayer liquid crystal (or laminated liquid crystal). A half mirror can be used for the first light splitter 4 .

In the display device CT, of the first light L1 emitted from the first light source S1 of the first display D1 through the backlight 55, one of the P-polarized light and the S-polarized light is transmitted through the first polarizing plate 40A, and the first liquid crystal The panel 51 and the second liquid crystal panel 52 are illuminated. The first light L1 transmitted through the second polarizing plate 40B and emitted from the first liquid crystal panel 51 is reflected by the first light splitter 4 as the first reflected light L2. The first reflected light L2 is retroreflected as retroreflected light L13 by the first retroreflection portion 2A, passes through the first light branching portion 4, and forms an aerial image I with the first light branching portion 4 interposed therebetween.

In contrast to the display device CT described above, as shown in FIG. 20, in the display device 1T(2) of the tenth embodiment, in the configuration of the display device 1T(2) described above, the first recursive light on the second emission axis J2 A first wave plate 21 is arranged behind the reflecting section 2A. The first wavelength plate 21 is a so-called λ/4 plate, and the first light splitter 4 uses a reflective polarizing plate. The direction of the reflective polarizing plate forming the first light branching portion 4 is parallel to the direction of the first polarizing plate 40A. That is, the first light branching portion 4 and the first polarizing plate 40B are arranged so as to form a parallel Nicols (or parallel Nicols) relationship. With such an arrangement, the first light L1 emitted from the second polarizing plate 40B has a crossed Nicols relationship with the first light branching portion 4, and hardly passes through the first light branching portion 4. It is reflected as the first reflected light L2 by the one-light branching unit 4 . After passing through the first wavelength plate 21 and entering the first retroreflecting portion 2A, the retroreflected light L13 reflected by the first retroreflecting portion 2A has a parallel Nicols relationship with the first light branching portion 4. , and passes through the first optical splitter 4 to form an aerial image I.

As shown in FIG. 21, in a display device 1T(2) that is another example of the tenth embodiment, the second polarizing plate 40B is removed from the configuration of the display device 1T(1) described above, and the first wave plate 21 is parallel to the width direction of the backlight 55 including the first light source S1, that is, along the direction forming an angle of 45 degrees with respect to the polarization direction of the first polarizing plate 40A. there is Therefore, in the display device 1T(2), the first light branching portion 4 and the first polarizing plate 40A are arranged so as to form a parallel Nicols (or parallel Nicols) relationship with each other. The first light L<b>1 emitted from the first liquid crystal panel 51 maintains a parallel Nicols relationship with the first light splitter 4 . The first reflected light L2 reflected by the first light splitter 4 passes through the first wave plate 21 and enters the first retroreflector 2A. After that, the retroreflected light L13 reflected by the first retroreflection portion 2A becomes parallel Nicols again with respect to the first light branching portion 4, passes through the first light branching portion 4, and forms an aerial image I. do.

As shown in FIG. 22, in the display device 1T(3), which is another example of the tenth embodiment, in the configuration of the display device 1T(1) described above, the second polarizing plate 40B on the first emission axis J1 is A first wave plate 21 is arranged in front. A second wave plate 22 is arranged behind the first retroreflection portion 2A on the second emission axis J2. In the configuration example of FIG. 22 , the first wave plate 21 is arranged near the surface of the second polarizing plate 40B on the side of the first light branching section 4 , and the second wave plate 22 is located near the surface of the first light branching section 4 . It is arranged near the surface on the side of the first retroreflective portion 2A. Furthermore, the orientation of the reflective polarizing plate forming the first light branching portion 4 is orthogonal to the orientation of the first polarizing plate 40A. That is, the first light branching portion 4 and the first polarizing plate 40A are arranged so as to form a crossed Nicols (or vertical Nicols) relationship. That is, the optical axes of the first wave plate 21 and the second wave plate 22 are arranged at 45 degrees with respect to the polarization direction of the second polarizing plate 40B.

Therefore, in the display device 1T(3), the first light L1 emitted from the first liquid crystal panel 51 passes through the second polarizing plate 40B, the first wave plate 21, and the second wave plate 22, respectively, and the first light branching A crossed Nicols relationship is formed with respect to the part 4 . The first reflected light L2 reflected by the first light splitter 4 passes through the second wave plate 22 and enters the first retroreflector 2A. After that, the retroreflected light L13 reflected by the first retroreflecting section 2A passes through the second wave plate 22 again, becomes parallel Nicols with respect to the first light branching section 4, and becomes the first light branching section 4. to form an aerial image I.

As shown in FIG. 23, in the display device 1T(4), which is another example of the tenth embodiment, the second polarizing plate 40B is removed from the configuration of the display device 1T(3) described above, and the first emission axis A first wave plate 21 is arranged in front of the first liquid crystal panel 51 on J1. Further, the orientation of the reflective polarizing plate forming the first light branching portion 4 is orthogonal to the orientation of the first polarizing plate 40A, and the first light branching portion 4 and the first polarizing plate 40A are crossed Nicols (or perpendicular to each other). Nicole) are arranged to form a relationship. On the other hand, the first wave plate 21 and the second wave plate 22 are arranged such that the optical axes of the first wave plate 21 and the second wave plate 22 form an angle of 45 degrees with respect to the optical axis of the first liquid crystal panel 51. there is

Therefore, in the display device 1T(4), the first light L1 emitted from the first liquid crystal panel 51 passes through the first wave plate 21 and the second wave plate 22, respectively, and becomes parallel to the first light splitter 4. Make a relationship with Nicole. The first reflected light L2 reflected by the first light splitter 4 passes through the second wave plate 22 and enters the first retroreflector 2A. After that, the retroreflected light L13 reflected by the first retroreflecting section 2A passes through the second wave plate 22 again, becomes parallel Nicols with respect to the first light branching section 4, and becomes the first light branching section 4. to form an aerial image I.

According to the display device 1T of the tenth embodiment described above, similarly to the display device 1A of the first embodiment, the user can enter the space A (that is, the space in which the user is present with respect to the first light branching section 4). , the aerial image I can be observed. Further, in a normal liquid crystal display, a polarizing plate is also arranged on the user side, and part of the light is absorbed by this polarizing plate. In particular, according to the display devices 1T(2) and 1T(4) of the tenth embodiment, the polarizing plate (that is, the second polarizing plate 40B) arranged on the user side in a normal liquid crystal display is removed. can be realized. As a result, the attenuation of light due to absorption by the polarizing plate is eliminated, and the brightness of the aerial image I is improved, so that the user can easily visually recognize the aerial image I. Secure aerial display and multi-layer display are easy on the user's eyes. can be realized.

Further, the method of displaying an aerial image to which the present invention is applied emits the first light L1 from the first light source S, and transmits the first light L1 from the first retroreflector 2 at a position on the first emission axis J1. a step of reflecting at least part of the first light L1 transmitted through the first retroreflecting portion 2 toward the first retroreflecting portion 2 as the first reflected light L2 by the first light branching portion 4; and a step of transmitting at least part of the first reflected light L2 retroreflected by the retroreflecting part 2 through the first light branching part 4 .
According to the aerial image display method described above, the aerial image I can be observed from a wider range of angles.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the scope of the claims. Transformation and change are possible.

For example, the configuration of the display device 1B shown in FIG. 4 may be changed as shown in FIG. That is, the first polarization splitter 25 of the display device 1B may be omitted, and the fifth display D5 may be employed instead of the first display D1. For example, a reflective polarizing film or the like can be used for the first light branching section 4 .

The plane of the fifth display D5 is divided into an S-wave light emitting portion SS1 that emits the S-polarized first light L1 and a P-wave light-emitting portion SP1 that emits the P-polarized first light L1. The S-wave light emitting unit SS1 may be, for example, a combination of an LED light source and a polarizing plate capable of emitting S-polarized light, but is not particularly limited. Also, the P-wave light emitting unit SP1 may be, for example, a combination of an LED light source and a polarizing plate capable of emitting P-polarized light, but is not particularly limited. Further, in the fifth display D5, a controller (not shown) can adjust polarized light (S wave or P wave) emitted for each predetermined area in the plane of the fifth display D5.

According to the display device 1M described above, the polarization of the first light L1 is adjusted by the S wave or the P wave for each predetermined area in the plane of the fifth display D5, and as shown in FIG. A direct image with P-wave polarized light or S-wave polarized light can be seen on the fifth display D5, together with the aerial image I with P-wave polarized light or with P-wave polarized light. Since the aerial image and the direct image are separated pixel by pixel, it is possible to display two layers of images independently while using a single display D5. Therefore, the display device 1M can be applied to DFD (Depth-fused 3D) display in which depth is perceived at positions corresponding to the respective luminance ratios of the S-wave light emitter SS1 and the P-wave light emitter SP1.

Further, as a modified example of the display device 1M, there is a display device 1N shown in FIG. The display device 1N omits the first wave plate 21 and the second wave plate 22 in the configuration of the display device 1M, and instead includes a fifth display D5 (first light source S1) on the first emission axis J1 and a second light source S1. A 3D film 44 is arranged between one retroreflective portion 2A. Examples of the 3D film 44 include a parallax barrier, a parallax barrier, and a lenticular lens.

According to the display device 1N described above, the polarization of the first light L1 is adjusted by the S wave or the P wave for each predetermined area in the plane of the fifth display D5, and as shown in FIG. An aerial image I with one of the wave polarized light and the P wave polarized light can be seen, and the left eye can see an aerial image I with the other of the S wave polarized light and the P wave polarized light. Therefore, the display device 1N can be applied to DFD display in which depth is perceived at a position corresponding to the luminance ratio of each of the S-wave light emitting unit SS1 and the P-wave light emitting unit SP1.

Further, in the display device according to the present invention, an imaging element may be arranged between the first light source S1 and the first retroreflector 2 on the first emission axis J1. Examples of imaging elements include lenticular lenses and fly-eye lenses. A three-dimensional display may be used as the display including the first light source S1 and the second light source S2.

Moreover, the display device according to the present invention may be housed in a housing or the like. FIG. 26 illustrates a configuration in which part of the configuration of the display device 1B according to the present invention is accommodated in the housing 30. As shown in FIG. Specifically, the housing 30 accommodates the first light source S1, the first display D1, the first retroreflective section 2, and the first wave plate 21 of the display device 1B. The first wave plate 21 is provided in contact with the upper surface side of the first retroreflection section 2 . A reflective polarizing plate (or a reflective polarizing sheet or the like) is provided as the first light splitter 4 on the upper surface of the housing 30 .
One of the P-polarized light and the S-polarized light of the first light L1 emitted from the first light source S1 is reflected by the first light branching unit 4, transmitted through the first wave plate 21, and retroreflected by the first retroreflection unit 2. It is reflected and passes through the first wave plate 21 again. At this time, the polarization of the first light L1 is changed, and the first light L1 is incident on and transmitted through the first light splitter 4 as the other of P-polarized light and S-polarized light, forming an aerial image I. Therefore, the user can observe the aerial image I from a certain direction E0. Such a display device is portable, flexibly adaptable to location and installation conditions, and can show an aerial image I to the user.

Further, in the display device according to the present invention, a prism sheet may be arranged in front of the first light source S1 on the first emission axis J1 or the display or the like provided with the light source described above. Here, the prism sheet (not shown) is formed by arranging a plurality of prism structures each having a triangular cross section in a predetermined direction on a base portion (substrate). The prism structure includes, for example, a right-angled triangular cross section in which the right-angled part is in contact with the base material, a right-angled triangular cross-section in which the long side is in contact with the base material, and an isosceles triangular cross-section. It is not particularly limited as long as it can be obtained. Such a prism sheet can be provided in the first light source S1, the second light source S2, the display, or the like so that a plurality of prisms are arranged in a direction orthogonal to the first emission axis J1.

By arranging the prism sheet in front of the first light source S1 on the first emission axis J1 or in front of the display or the like including the light source, the first light L1 is refracted in a predetermined direction on the surface of the prism. Therefore, by appropriately setting the angle of the surface of the prism structure protruding from the base material, light can be collected at the position where the aerial image I is formed, and the brightness of the aerial image I can be improved, compared to the case where no prism sheet is provided. be able to. Further, it is conceivable that the edge portion of the aerial image I is blurred due to the influence of light scattering and diffraction. However, the edges of the aerial image I can also be sharpened by using a prism sheet.

Further, in front of the first light source S1 on the first emission axis J1 or the display equipped with the above-described light source, a plurality of prisms having the same type and pitch of the prism structure, or different ones may be stacked. good. Thereby, the refraction direction of the first light L1 can be finely set.

27, the display device according to the present invention can have a configuration in which the casing 30 is omitted from the display device shown in FIG. If there is f) in FIG. 24, it can be utilized as a contact determination device based on detection of a large amount of scattered light. Conventionally, when attempting to detect scattered light, the camera CC was placed at the position indicated by the broken line in FIG. The contact of any object to the image I can be sensitively detected and determined.

Next, an example that was conducted to prove the effect of the display device of each embodiment according to the present invention will be described. In addition, the present invention is not limited to the following examples.

(Example 1)
In order to configure the display device 1A shown in FIG. 1, an LED that emits visible light was used as the first light source S1. Also, a special display was prepared in which a plurality of first light sources S1 were arranged on the surface of the first display D1. For the first retroreflective portion 2, a retroreflective sheet (product name: high-gloss reflective trim 6160R, manufacturer: 3M) having a unit structure 10 with a size of about 180 μm and made of transparent plastic was used. A half mirror was used for the first light splitter 4 .
In the constructed display device 1A, when the character "A" is displayed on the first display D1, as shown in FIG. 28, it is confirmed that the first light source S1 and the aerial image I of the character "A" are observed. did.

(Example 2)
Two first displays D1 similar to those in Example 1 were used to configure the display device 1E shown in FIG. A retroreflective sheet similar to that used for the first retroreflective section 2 was used for the second retroreflective section 6 .
In the constructed display device 1E, when the first display D1 displays, for example, the letter "A" and the first display D1 displays, for example, the letter "B", as shown in FIG. In this case, the aerial image I of the character "A" and the character "B" by the second light source S2 of the second display D2 can be seen. It was confirmed that "B" was observed by the first light source S1 of the one display D1.

(Example 3)
In order to configure the display device 1G shown in FIG. 9, an LED that emits visible light was used as the first light source S1 as in the first embodiment. A corner cube type retroreflective sheet having a retroreflective structure 3A (product name: retroreflective sheet QR-1 with retardation film, manufacturer: SN Partners Co., Ltd.) was used for the first retroreflective portion 2C. As the first light branching part 4, a reflective polarizing film (product name: SHM-2, manufacturer: SN Partners) pasted on a transparent acrylic plate was used.
In the constructed display device 1G, when the character "T" is displayed on the fourth display D4, as shown in FIG. 30, the first light source S1 and the aerial image I of the character "T" are observed. did.

Further, instead of the retroreflective sheet having the retroreflective structure 3A, a bead-type retroreflective sheet having the retroreflective structure 3B (product name: ultra-high brightness reflective sheet 7610, manufacturer: 3M Co., Ltd.) is used for the display device 1G. ' was constructed.
In the constructed display device 1G', when the character "A" is displayed on the fourth display D4, the first light source S1 and the aerial image I of the character "A" are observed as shown in FIG. confirmed.

(Example 4)
In the display device 1G of Example 3, the first light branching part 4 is inclined at approximately 45° with respect to the surface of the fourth display D4 (that is, the first light source S1 and the first retroreflection part 2C). By arranging them, the display device 1H shown in FIG. 11 was configured.
In the constructed display device 1H, when the character "T" is displayed on the fourth display D4, as shown in FIG. 32, the first light source S1 and the aerial image I of the character "T" are observed. did.

(Example 5)
In the display device 1H of Example 4, the first retroreflective portion 2C is moved to the position P2 in the emission direction E1 of the first light L1 with reference to the first light source S1 on the first emission axis J1, and the first emission axis J1 A display device 1H shown in FIG. 11 was constructed by disposing a polarizing plate 40 between the upper first light source S1 and the first retroreflection portion 2C. A polarizing film (product name: polarizing film HN42, manufacturer: Polaroid) was used for the polarizing plate 40 .
In the constructed display device 1H, when the letter "T" is displayed on the fourth display D4, as shown in FIG. (ie, direct transmitted light) was blocked, so only the aerial image I of the letter "T" was observed.

(Example 6)
In order to configure the display device 1P shown in FIG. 15, an LED that emits visible light was used as the first light source S1 as in the first embodiment. An LED tape was used in which three LEDs were arranged at intervals in the width direction, and a plurality of LEDs were arranged at predetermined intervals in the length direction. A corner cube type retroreflective sheet having a retroreflective structure 3A (product name: Nikkalite Crystal Grade, manufacturer: Nippon Carbide Industry Co., Ltd.) was used for the first retroreflective portion 2C. As the first light branching portion 4, a reflective polarizing film (product name: SHM-2, manufactured by SN Partners Co., Ltd.) was attached to a transparent acrylic plate.
In the constructed display device 1P, as shown in FIG. 34, it was confirmed that an aerial image I composed of a plurality of spotlights corresponding to the LEDs arranged on the LED tape and a virtual image were observed.

Furthermore, as shown in FIG. 16, an LED tape having LEDs arranged on both sides was used to construct a display device 1Q having a first light source S1 and a second light source S2. Such a double-sided LED tape corresponds to one in which the first light source S1 and the second light source S2 shown in FIG. 16 are arranged apart from each other by the thickness dimension of the tape substrate. By arranging the light sources on both sides of the tape in this manner, it was confirmed that the aerial image I and the virtual image were observed from both sides of the LED tape, as shown in FIG.

(Comparative Example 1, Example 7)
In order to configure the display device 1T shown in FIGS. 20 to 23, a special color display (first liquid crystal display 51 and second display 52) provided with a plurality of LEDs emitting visible light was prepared as the first light source S1. Specifically, as the backlight 55, the first liquid crystal display 51, and the second display 52, a high-definition high-brightness LED panel (pitch 4 mm, surface mount package type, product name: P4-LED panel, distributor: WAN Color) , and a disassembled polysilicon TFT liquid crystal panel (product name: LTM10C348S, manufacturer: Toshiba Corporation) were used. A retroreflective sheet (product name: Nikkalite Crystal Grade, manufacturer: Nippon Carbide Industry Co., Ltd.) made of transparent plastic and having a size of the unit structure 10 of about 180 μm was used for the first retroreflective portion 2A. . In the first light branching part 4, a commercially available half mirror (both reflectance and transmittance are about 50%) or a reflective polarizing film (product name: SHM-2, manufacturer: SN Partners Co., Ltd.) is pasted on a transparent acrylic plate. I used what I found. As the first polarizing plate 40A and the second polarizing plate 40B, a polarizing plate obtained by disassembling the above-mentioned polysilicon TFT liquid crystal panel or a commercially available polarizing plate (product name: HN42, manufacturer: Polaroid Co., Ltd.) is used. used. A commercially available λ/4 plate was used for the first wave plate 21 and the second wave plate 22 .

The display device CT shown in FIG. 19 and the display device 1T shown in FIGS. 20 to 23 were respectively constructed using the components described above, and formed from the color image shown in FIG. 36 displayed on the special color display. Each aerial image I is captured by a camera (product name: D5500, manufacturer: Nikon Corporation) and a lens (product name: FS DX NIKKOR 18-140mm f / 3.5-5.6G ED VR, manufacturer: Corporation The image was taken using a Nikon). The F value of the imaging camera was set to 4.8, and the shutter speed during imaging was set to 1/10 (ISO: 400).
Note that both FIGS. 36 and 41 are shown as grayscale images.

In the display device CT constructed as a comparative example, a half mirror was used as the first light splitter 4, and an aerial image I corresponding to the image of the special color display was picked up as shown in FIG.

In the display device 1T(1) constructed as an example, a reflective polarizing plate is used instead of a half mirror as the first light branching unit 4, and the configuration described above is used. An aerial image I brighter than the aerial image I shown in FIG. 37 was captured.

In the constructed display device 1T(2), a reflective polarizing film (product name: SHM-2, manufacturer: SN Partners Co., Ltd.) pasted on a transparent acrylic plate is used as the first polarizing plate 40A. Moreover, by not using the second polarizing plate 40B, the loss of the first light L1 was suppressed, and as shown in FIG. 39, an aerial image I sharper than that in FIG. 38 was captured.

In addition, as shown in FIG. 40, the constructed display device 1T(3) picked up an aerial image I with brightness similar to that of the display device 1T(1) shown in FIG.
Furthermore, in the constructed display device 1T(4), the above-described reflective polarizing film is used as the first polarizing plate 40A, and the second polarizing plate 40B is not used, and the first wave plate 21 and the second wave plate 22 are used. As a result, as shown in FIG. 41, an aerial image I that was brighter than the aerial image I of the display device 1T(3) shown in FIG. 40 but had a slightly lower contrast was captured.

(Example 8)
In the display device 1T(2) constructed in Example 7, the first liquid crystal panel 51 displays an image of the letter "F" in a single color, and the second liquid crystal panel 52 displays a single color "B". An aerial image I was taken when an image of characters was displayed. The F value of the imaging camera was changed to 3.5, and the shutter speed during imaging was kept at 1/10 (ISO: 400).

It was confirmed that the aerial images I shown in FIGS. 42, 43, and 44 were formed as a result of photographing from the left direction, the front direction, and the right direction with respect to the direction facing the aerial image I. The aerial image I taken from the front direction is the brightest and clearest, but it was confirmed that the characters "F" and "B" can be clearly read even when the aerial image I is taken from the left and right directions. did. A parallax corresponding to the distance between the two layers was observed from the left and right, confirming that a deep aerial image I was formed.

In the above configuration, instead of the letters "F" and "B", a belt-shaped single-color dot pattern (drawing) whose density changes continuously in the horizontal direction with respect to the direction facing the aerial image I is displayed. and photographed the formed aerial image I. It was confirmed that the respective aerial images I shown in FIGS. 45, 46, and 47 were formed. Also, the monochromatic dot pattern was observed to have depth in the oblique direction.

(Example 9)
In the display device 1T(4) constructed in Example 7, as shown in FIG. 48, a wave plate 53 can be arranged between the first liquid crystal panel 51 and the second liquid crystal panel 52 on the first emission axis J1. Then, a color correction test was conducted. The wave plate 53 is a so-called λ/2 plate, and provides a phase difference of π in the electric field vibration direction of incident light.

FIG. 49 shows an aerial image I taken before the wavelength plate 53 is arranged, that is, in the display device 1T(4). On the other hand, in FIG. 50, the wavelength plate 53 is arranged between the first liquid crystal panel 51 and the second liquid crystal panel 52 on the first emission axis J1, and the optical axis of the wavelength plate 53 is the width direction of the backlight 55. 4 shows an aerial image I photographed when the wavelength plate 53 is arranged along a direction forming an angle of 45 degrees with respect to . As can be seen from FIG. 50, when the wavelength plate 53 is arranged, the coloring phenomenon due to wavelength dispersion is eliminated, and the color of the portion where the red aerial image I was formed before the wavelength plate 53 is arranged is changed. It's gone. That is, both FIGS. 49 and 50 are grayscale images, but the “colored portion” shown in FIG. 50 is darker than the “colored portion” shown in FIG. , it can be confirmed that the aforementioned coloring phenomenon is eliminated.

As can be seen from the embodiments described above, according to the display device to which the present invention is applied, the aerial image I can be observed from a wider angle, and effects can be obtained in various configurations.

1A, 1B, 1C, 1D, 1E, 1F, 1G, 1H, 1K, 1M, 1N, 1P, 1P', 1Q, 1R, 1T(1), 1T(2), 1T(3), 1T(4) , 1V, 1W... display device 2... first retroreflection section 4... first light branching section 5... second light branching section 6, 7... second retroreflection section 21... first wave plate 22... second wave plate 23 Third wave plate 24 Fourth wave plate 50A First reflector 50B Second reflector E1, E2 Emission direction L1 First light L2 First reflected light L21 Second light S1 First light source S2... Second light source

Claims (4)

a first light source that emits the first light;
a first light branching unit and a second light branching unit arranged to face each other with the first light source interposed in the first direction;
a retroreflective portion disposed on a side of one of the first light branching portion and the second light branching portion opposite to a side facing the other light branching portion;
with
By directing the emission part of the first light source toward the space formed between the first light branching part and the second light branching part,
the first light enters the first optical branching section and the second optical branching section;
The one light branching part reflects a part of the first light from the first light source as the first reflected light and transmits another part of the first light. reflecting part of the first reflected light and transmitting another part of the first reflected light;
The retroreflection section retroreflects the first light and the first reflected light transmitted through the one light branching section,
display device. The retroreflective section is arranged with a predetermined distance from the one light branching section in the first direction,
The display device according to claim 1. A surface of the one optical branching portion facing the other optical branching portion is inclined with respect to a surface of the other optical branching portion facing the one optical branching portion,
The display device according to claim 1 or 2. a first light source that emits the first light;
a second light source that emits a second light;
a first light branching unit and a retroreflecting unit arranged to face each other with both the first light source and the second light source interposed in a first direction;
a second light branching portion disposed on a surface of the retroreflective portion facing the first light branching portion in the first direction;
with
The first light branching part reflects part of the first light from the first light source, transmits another part of the first light, and splits the second light from the second light source. Part of the light is reflected, another part of the second light is transmitted, part of the light reflected by the retroreflection part is reflected, and another part of the light reflected by the retroreflection part through the
The retroreflecting section retroreflects at least part of each of the first light, the second light, and the light reflected by the first light branching section.
display device.

Images