JP2023008330A - Holography reproduction illumination light irradiation device and holographic display - Google Patents

Abstract

To provide a holography reproduction illumination irradiation device and display that make it possible for a plurality persons to view a reproduction image of hologram simultaneously, and can solve a problem of a conventional art like a vision area is narrow.SOLUTION: The present holographic display 10 comprises a vertical emission type Optical Phased Array (OPA) 13 that: causes light from a light source 11 to be incident laterally, and causes zero-order light of the incident light 12 to propagate laterally on a reverse side while causing the zero-order light thereof be iteratively reflected internally on a front and rear face; and emits, to an external air layer, light to be used as reproduction light 16 of light incident upon an interface between a space light modulation element (SLM) 14 and the front face or rear face in accordance with a hologram pattern to be displayed on the SLM 14 to be disposed in close contact with the front face or rear face. The vertical emission type OPA 13 has a grating structure that extends in a propagation direction of the zero-order light and diffracts and emits the incident light in both of the front and rear directions.SELECTED DRAWING: Figure 1

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a holographic reconstruction illumination light irradiation device and a holographic display having a compact reconstruction illumination optical system.

Holography is a three-dimensional image technology that can reproduce the state of an observed object as it is. When recording a hologram that stores three-dimensional image information, light from a light source is divided into two systems, one of which is applied to an object as object light, and the other is used as reference light, both of which are made incident on a recording medium. The object beam and the reference beam are caused to interfere with each other, and the generated interference fringes are recorded as a hologram in the recording medium. When reproducing the hologram, the object light (reconstruction light: wavefront from the object) is reproduced by causing the reference light used during recording to enter the hologram as reconstruction illumination light.

Conventionally, the above-mentioned holographic display has a problem that the reproducing illumination optical system is large, and it is difficult to reduce the size and thickness of the device. In order to solve this problem, a technique has been proposed in which a holographic optical element using a volume hologram is used in the reconstruction illumination optical system.
In this method, light incident from the side of the display surface is diffracted by a holographic optical element, and the light emitted as plane waves is used as reproduction illumination light. By doing so, it is possible to reduce the size and thickness of the holographic display.

Furthermore, recently, by using an optical waveguide grating, the incident light from the side of the holographic display is taken out in the vertical direction, and the light is used as the reconstruction illumination light for the hologram. It is known that displays can be constructed.
On the other hand, this system uses an amplitude-modulation spatial light modulator with sparse pixel spacing, and there is a problem that the range (viewing zone) in which 3D images can be properly viewed is narrow. , To solve that problem, this system is equipped with a field lens and applies viewpoint tracking technology. That is, by detecting the vicinity of the position of the observer's eyes using viewpoint tracking technology and generating hologram data in real time so that a 3D image can be viewed from that position, the problem of a narrow viewing zone is solved to some extent. there is
In addition, since the amplitude modulation type spatial light modulator is used, the 0th order light that is transmitted without being modulated is always generated. are adjusted so that the 0th-order light does not enter the eye (see Non-Patent Document 1 below).

J. An et al., “Slim-panel holographic video display,” Nature Communications 11, 5568 (2020).

However, in the method described in Non-Patent Document 1, a viewpoint tracking technique is used, and it is not possible to detect the viewpoint position of one person's eye and focus the reproduced light on that one point. However, since it is difficult to detect the viewpoint positions of the eyes of a plurality of people and focus the reproduced light on the viewpoint position of each person, the holographic display is limited to one person. there were.
In addition, in the method described in Non-Patent Document 1, the above-described viewpoint tracking technology is used, and hologram data is generated in real time. Since it is easy to deviate from the reproducible range, the problem of a narrow viewing zone still exists.

The present invention has been devised in view of the above circumstances, and provides a holographic reproduction illumination light irradiation apparatus that enables a plurality of people to view a reproduced image of a hologram at the same time and solves the problem of the prior art that the viewing zone is narrow. The object is to provide a holographic display.

That is, in the reproduction illumination light irradiation device for holography of the present invention,
a light source;
The light from the light source is incident from the side, and the 0th order light of the incident light is repeatedly internally reflected on the front surface and the back surface and propagated to the side opposite to the incident side of the light, According to the hologram pattern displayed on the spatial light modulation element arranged in close contact with the front surface or the back surface, the light that is used as the reproduction light from the light incident on the interface with the spatial light modulation element from the inside is selected. , and an optical phased array that emits to an air layer outside the surface side,
The optical phased array has a grating structure extending in the propagation direction of the 0th order light, and is configured to diffract the light incident on the optical phased array at a predetermined angle in the front surface direction and the back surface direction. It is characterized by having
Moreover, it is preferable that the grating period of the grating structure satisfies the following formula (A).
|n _e −λ/Λ|>1 (A)
is the wavelength of the incident light, _.LAMBDA . is the grating period, and ne is the effective refractive index of the grating.

Next, the holographic display of the present invention is
The present invention is characterized by comprising any one of the reproduction illumination light irradiation devices for holography described above and the spatial light modulation element.
In this holographic display, the spatial light modulating element can be a transmissive spatial light modulating element in close contact with the surface side of the optical phased array. In this case, out of the diffracted light from the optical phased array side, the 0th order light incident from the inside on the interface between the optical phased array and the transmissive spatial light modulator is totally reflected at the interface. On the other hand, the light that enters the interface from the inside and is used as the reproduction light is configured to pass through the spatial light modulator and exit to the air layer on the surface side of the optical phased array. is preferred.

Moreover, in the holographic display of the present invention, the spatial light modulation element can be a reflective spatial light modulation element in close contact with the back side of the optical phased array. In this case, out of the diffracted light from the optical phased array side, the 0th order light incident from the inside on the interface between the optical phased array and the reflective spatial light modulator is totally reflected at the interface. On the other hand, the light that enters the interface from the inside and is used as the reproduction light is reflected by the spatial light modulator and emitted from the surface side of the optical phased array to the air layer. is preferred.

Also, in the holographic display of the present invention, the optical phased array is either passive or active.

According to the reproduction illumination light irradiation device for holography and the holographic display of the present invention, the 0-order light irradiated on the inner surface of the light phased array is set to be irradiated to the inner surface at an incident angle such that the light is totally reflected. Therefore, it is possible to prevent the zero-order light from entering the observer's eyes, so it is not necessary to use the viewpoint tracking technique as in the prior art.
Therefore, it is possible to solve the problems that many people cannot observe and that the viewing area is narrow, which are problems in the case of using the viewpoint tracking technology. That is, it is possible to allow a plurality of people to visually recognize the reproduced image of the hologram at the same time, and to prevent the occurrence of the problem that even if the observer moves left or right at a rapid timing, the reproduced image of the hologram is deviated from the possible range of the reproduced image of the hologram. can be done.

BRIEF DESCRIPTION OF THE DRAWINGS It is a conceptual diagram (A) for demonstrating the structure which becomes the premise of the holographic display which concerns on embodiment of this invention, and an enlarged view (B) which shows notionally the vertical emission type OPA of them. 1 is a schematic diagram for explaining the main parts of a holographic display (when a transmissive SLM is used) according to a first embodiment; FIG. FIG. 4 is a conceptual diagram for explaining the effects of the holographic display according to this embodiment; FIG. 10 is a schematic diagram for explaining the main parts of a holographic display (when a reflective SLM is used) according to a second embodiment; 1 is a block diagram showing a schematic configuration of a holographic display using a passive reproduction illumination optical system according to Application Example 1 of the present invention; FIG. FIG. 11 is a block diagram showing a schematic configuration of a holographic display calibration device using a passive reproduction illumination optical system according to Application Example 2 of the present invention; FIG. 11 is a block diagram showing a schematic configuration of a holographic display using an active reproduction illumination optical system according to Application Example 3 of the present invention; FIG. 11 is a block diagram showing a schematic configuration of a holographic display calibration device using an active reproduction illumination optical system 1 according to Application Example 4 of the present invention; FIG. 11 is a block diagram showing a schematic configuration of a holographic display calibration device using an active reproduction illumination optical system 2 according to Application Example 5 of the present invention; FIG. 4 is a schematic diagram of a prior art holographic display used for explanation in contrast to the embodiment of the holographic display shown in FIG. 3;

A holographic display according to an embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram showing the prerequisite configuration of the holographic display according to this embodiment, and FIG. 2 is a schematic diagram for explaining the configuration of the main part of the holographic display according to this embodiment. 3 is a conceptual diagram for explaining the effects of the holographic display according to this embodiment.

As shown in FIG. 1(A), a holographic display 10 according to the present embodiment has a light source 11 such as a laser light source, and light (incident light) 12 from the light source 11. The light 12 is emitted in a vertical direction. (surface direction), only the diffracted light that becomes the reproduction illumination light 15 is emitted into the spatial light modulator (SLM: the same shall apply hereinafter) 14, and the 0th order light as unnecessary light is subjected to repeated internal total reflections to the side. A vertical emission type OPA 13 propagating in the direction of light and the spatial light modulator 14 are provided.

Here, the spatial light modulator 14 is composed of, for example, a liquid crystal display device or the like, and a hologram is displayed based on the input hologram data. and emits the reproduction light 16 . A three-dimensional reconstructed image 17 of the subject is reconstructed by the emitted reconstructed light 16 .
The light source 11 and the vertical emission type OPA 13 constitute the holographic reproduction illumination light irradiation device according to the embodiment of the present invention, and the holography reproduction illumination light irradiation device and the spatial light modulator 14 constitute the holographic reproduction light irradiation device according to the embodiment. A display is configured.

As shown in FIG. 1B, the vertical emission type OPA 13 is configured as an n-channel (e.g., 8-channel) optical waveguide type optical deflection device. That is, this vertical emission type OPA 13 includes an optical splitter 22 that splits the incident light 12 into n-channel waveguides, a phase shifter 23 that controls the phase of the light in each channel, and the light from each phase shifter 23. A grating 24 is provided which diffracts the light in the direction of the surface to produce the emitted light 15 . 2, each part of a lower clad 52, a core 53 and an upper clad 55 is laminated on the substrate 51 in the thickness direction.

Further, as shown in FIG. 2, the light diffracted in both the vertical direction by the grating 54 is hologram-modulated on the spatial light modulator 14a at the interface between the upper clad 55 of the vertical emission type OPA 13a and the spatial light modulator 14a. The light is modulated by the pattern and separated into the reproduced light 16a which is the original data of the three-dimensional image and the 0th order light 18 which is totally reflected at the interface.

Electrodes (not shown) are arranged above and below each phase shifter 23, and by changing the voltage between both electrodes, the light emitted from the grating 54 of each waveguide is controlled by the EO effect. The phase of a certain reproduction light 16a can be controlled. In the holographic display calibration device, which will be described later, the phase of the reproduced light 16a is controlled in this way. It is also possible to control the phase using the TO effect or the like instead of the EO effect.

Next, the motion of light in the grating portion 54a, which is the point of this embodiment, will be described in detail with reference to FIGS. 2 and 3. FIG. In the specification of the present application, the term "grating section" refers not only to the grating 54 formed in the core 53, but also to the lower clad 52 and the upper clad 55 located in the region corresponding to the grating 54, and further to the upper clad 55 and the space. A region portion including an interface between the optical modulators 14a is referred to.

As shown in FIG. 2, the incident light 12a propagating through the optical waveguide and entering the grating portion 54a from the left side of the drawing along the core 53 is diffracted by the grating 54 in both the vertical direction.

In general, the reconstruction illumination light, which is the emitted light from the vertical emission type OPA 13a and is irradiated to the spatial light modulator 14a, is modulated by the hologram pattern displayed on the spatial light modulator 14a and becomes the original data of the three-dimensional image. 16a and zero-order light, which is unnecessary light that passes through the spatial light modulator 14a as it is without being modulated by the hologram pattern.
However, when the 0-th order light, which is unnecessary light, is emitted to the air layer 85, it is necessary to prevent it from entering the observer's eyes. It has become necessary to mount a system (member) related to this in a holographic display.

Therefore, in the present embodiment, by setting the configuration so as to satisfy the following formula (A), the light from the grating portion 54a is not emitted to the air layer 85, but is propagated rightward in the drawing by total reflection. is set to
That is, the output angle _θc of the light from the grating 54 in the claddings 52 and 55 is
sin θ _c =(n _e −λ/Λ)/n _c
satisfies the following equation. is the wavelength of light, _.LAMBDA . is the period of the grating 54, _n.sub.e is the effective refractive index of the grating 54, and .n.
According to Snell's law, the emission angle θ of light from the grating portion 54a to the air layer 85 is
sin θ=n _c sin θ _c =n _e −λ/Λ
By satisfying the following formula (A), total reflection occurs at the interface between the upper clad 55 and the air layer 85 , and no light is emitted to the air layer 85 .
|n _e −λ/Λ|>1 (A)

The above description is for light diffracted upward from one point on the grating 54, while light diffracted downward from one point on the grating 54 is reflected by the substrate 51 of the vertical emission OPA 13a. After that, it goes obliquely upward and is incident on the spatial light modulator 14a. These incident light beams are modulated by the hologram pattern displayed on the spatial light modulator 14a to form the reconstructed light beam 16a which is the original of the three-dimensional image, and the zero-order light beam 18 which is transmitted without being modulated.
When the total reflection condition (A) described above is satisfied, total reflection occurs at the interface between the spatial light modulator 14a and the air layer 85, and the zero-order light is not emitted to the air layer. Incident light to the spatial light modulator 14a) is set to a value that satisfies the total reflection condition (A).

Although FIG. 2 shows only light in the vertical direction from one point of the grating 54, in reality, the above phenomenon occurs for each diffracted light from each point (lattice point) of the grating 54. .
As a result, only the reproduced light 16a that is modulated by the hologram pattern displayed on the spatial light modulator 14a and becomes the original data of the three-dimensional image is emitted to the air layer 85, and the zero-order light that is unnecessary light is emitted to the air layer 85. The light is propagated laterally while being totally reflected by the upper and lower inner surfaces of the vertical emission type OPA 13a.

Therefore, unlike the prior art, there is no need to provide a system (member) or the like related to viewpoint tracking technology for zero-order light, which is unnecessary light emitted from the spatial light modulator 14a to the air layer 85, and the device size and cost are reduced. It is advantageous in terms of Also, a large number of people can observe the hologram reproduction image at the same time.

In the conventional holographic display, as shown in FIG. 10, the incident light 812a is incident from the side, and the diffracted light 840 is diffracted and emitted in the vertical direction. ) 840 is used as a backlight to illuminate the spatial light modulator 814a displaying the hologram. Some 0th order light 818 is emitted into the air layer.

The reproduced light 816a and the 0th order light 818, which is unnecessary light, are set to converge on one point after passing through the field lens 819 respectively. Based on this detection, hologram data is generated in real time so that the reconstructed light 816a is focused on the position of the eye and the 0th order light 818 is focused on a position other than the eye. ing.

However, when using the field lens 819 and viewpoint tracking technology as shown in FIG. 10, first, the viewpoint position of the observer's 820 eyes is detected, and hologram data is generated so that a three-dimensional image can be viewed from that position. However, even if the viewpoint position of one person's eye can be detected and the reproduced light can be focused, the viewpoint position of each eye of a plurality of people is detected and the reproduced light is focused on each viewpoint position. Since it is difficult to generate hologram data in terms of time, there is a problem that the holographic display is limited to one-person use.
In addition, in the conventional technology described above, since the viewpoint tracking technology is used and the hologram data is generated in real time, if the observer moves to the left or right at a rapid timing, it is likely to go out of the reproduction range of the stereoscopic image. In some cases, the problem of a narrow viewing zone arises.

On the other hand, in the holographic display of the present embodiment, as shown in FIG. 3, the grating section 54a for diffracting the incident light 12a incident from the side and emitting the diffracted light in the vertical direction is a spatial light modulator. 0th order light 18a, which is unmodulated unnecessary light out of the light incident on 14a, is repeatedly totally reflected and propagated to the side of this grating section 54a. , so that it does not reach the observer 20 . As a result, the light emitted from the spatial light modulator 14a to the air layer (85) does not contain the 0-order light 18a, and only the reproduced light 16a reaches the observer 20. Therefore, the viewpoint tracking technique is used. Therefore, a plurality of observers 20 can visually recognize a clear holographic three-dimensional image at the same time.
In addition, since the viewpoint tracking technology is not used, even if the observer moves to the left or right at a rapid timing, the viewing area can be expanded without going out of the reproduction range of the stereoscopic image.

In the above embodiment, the transmission type SLM is used as shown in FIG. 2, but instead of this, a reflection type SLM as shown in FIG. 4 may be used.
That is, the incident light 112a propagating through the optical waveguide, which enters the grating portion 154a from the left side of the drawing along the core 153, is diffracted in both the vertical direction by the grating 154. FIG.

The diffracted light is applied to the spatial light modulator 114a as reconstruction illumination light, is modulated by the hologram pattern displayed on the spatial light modulator 114a, and is emitted as reconstruction light 116a serving as original data for a three-dimensional image. On the other hand, the zero-order light, which is unnecessary light, also satisfies the condition (A') of being totally reflected at the interface between the upper clad 155 and the air layer 185 in the embodiment shown in FIG.

That is, the configuration is set so as to satisfy the following formula (A').
|n _e −λ/Λ|>1 (A′)
is the wavelength of light, _.LAMBDA . is the grating period, and ne is the effective refractive index of the grating. The output angle θ _c ′ of the light from the grating portion 154 a within the clads 152 and 155 can be expressed by the following formula, where n _c is the refractive index of the clads 152 and 155 .
sin θ _c ′=(n _e −λ/Λ)/n _c
According to Snell's law, the emission angle θ' of light from the grating portion 154a to the air layer 185 is
sin θ′=n _c sin θ _c ′=n _e −λ/Λ
By satisfying the condition (A′), total reflection of light occurs at the interface between the clads 152 and 155 and the air layer 185 , and no light is emitted to the air layer 185 .
The 0th-order light 118a repeats total reflection at the interface between the upper clad 155 and the air layer 185 and is incident on the spatial light modulator 114a while being propagated rightward in the drawing. The exit angle θ _c ' within the claddings 152, 155 is preserved. The incident angle θ _{1 ' from the upper clad 155 to the air layer 185 and the incident angle θ 2 '} from the lower clad 152 to the spatial light modulator 114a are set to be equal, θ ₁ '=θ ₂ '. =θ _c ' is satisfied.

That is, the light diffracted downward from one point of the grating 154 is incident on the spatial light modulator 114a. On the other hand, the light diffracted upward from one point of the grating 154 is totally reflected at the interface between the upper clad 155 and the air layer 185, and then directed downward to enter the spatial light modulator 114a.
Thereafter, the reflection angle of the 0-order light that repeats total reflection on the upper and lower inner surfaces of the vertical emission type OPA 113a is propagated while being preserved.

Although FIG. 4 also shows only light in the vertical direction from one point of the grating 154 as in the case of FIG. The above phenomenon occurs for each diffracted light.
As a result, only the reproduced light 116a that is modulated by the hologram pattern displayed on the spatial light modulator 114a and becomes the original data of the three-dimensional image is emitted to the air layer 185, and the zero-order light that is unnecessary light is emitted to the air layer 185. The light is propagated laterally (to the right in FIG. 4) while being totally reflected between the upper and lower inner surfaces of the vertical emission type OPA 113a.

Configurations of application examples of the holographic display and the holographic display calibration apparatus using the principle of the holographic display according to the above embodiment will be briefly described below with reference to the block diagrams of FIGS.
FIG. 5 is a block diagram showing a schematic configuration of a holographic display using the passive reconstruction illumination optical system according to Application Example 1, and FIG. A block diagram showing a schematic configuration of a holographic display calibration device used, FIG. 7 is a block diagram showing a schematic configuration of a holographic display using an active reproduction illumination optical system according to Application Example 3, A block diagram showing a schematic configuration of a holographic display calibration apparatus using the active reconstruction illumination optical system 1 according to Example 4, and FIG. 9 is a holographic display using the active reconstruction illumination optical system 2 according to Application Example 5. 1 is a block diagram showing a schematic configuration of a calibration device; FIG.

Since these application examples are similar in usage mode and basic configuration of the present embodiment, only application examples 1 and 2 will be described with respect to the overall configuration in order to avoid duplication of explanation. As for application examples, blocks having functions similar to those of application examples 1 and 2 are omitted by aligning the last two digits of the symbols with those of application examples 1 and 2, and the application Only the configuration specific to the example will be described.

<Application example 1>
First, application example 1 will be described with reference to FIG. As described above, this holographic display uses a passive reproduction illumination optical system, and includes a light source 211, a light input section 230 into which light from the light source 211 is incident, and this incident light 212 is incident, It has an optical splitter 222 that splits light into a predetermined number of channels (a natural number n may be sufficient), and a grating section 224 that guides the split light 226 . Here, the optical input section 230, the optical splitter 222, and the grating section 224 constitute a vertical emission type OPA 213. FIG. In addition, the grating unit 224 irradiates the spatial light modulator 214 with the emitted light 215 that functions as the reproduction illumination light of the spatial light modulator 214, and the zero-order light that is unnecessary light that has not been modulated by the spatial light modulator 214 is discharged laterally.

A hologram image is displayed on the spatial light modulator 214 by the following signal processing. That is, based on the 3DCG data and the reference beam data 227 from the data holding unit 231, the hologram data 228 is output from the hologram generation unit 232, and the drive signal 229 from the spatial light modulator control unit 233 based on this hologram data 228, Each pixel of spatial light modulator 214 is driven, and a hologram image is displayed on spatial light modulator 214 .
The spatial light modulator 214 on which the hologram image is thus displayed is irradiated with the reconstruction illumination light. The emitted light can be only the effective reproduction light 216 that does not contain unnecessary 0th order light, and a reproduced image 217 with excellent S/N can be obtained.

<Application example 2>
Next, application example 2 will be described with reference to FIG. As described above, this apparatus is a calibration apparatus using a passive type reproduction illumination optical system. It has an optical splitter 322 that splits light into a predetermined number of channels, and a grating section 324 that guides the split light. In addition, a distributor 321 for branching the measurement light 365 from the incident light 312 from the optical input section 330, a measurement phase shifter 343 for receiving the measurement light and emitting the phase-modulated light, and a phase-modulated It is equipped with a measuring optical waveguide 344 that receives light 366 and emits emitted light 367 to the camera 341 . Here, the optical input section 330 , the optical splitter 322 , the grating section 324 , the distributor 321 , the measurement phase shifter 343 and the measurement optical waveguide 344 constitute the vertical emission type OPA 313 .

Moreover, the grating unit 324 irradiates the spatial light modulator 314 with the emitted light 315 that functions as the reproduction illumination light of the spatial light modulator 314, and directs the zero-order light that has not been modulated by the spatial light modulator 314 to the air layer. Limit emanations.
A hologram image is displayed on the spatial light modulator 314 by the following signal processing. That is, the measurement pattern 364 is sent from the camera control/wavefront analysis unit 342, and each pixel of the spatial light modulator 314 is driven by the driving signal 329 from the spatial light modulator control unit 333 to which the measurement pattern 364 is input. A hologram image is displayed.

The spatial light modulator 314 on which the hologram image is displayed is irradiated with the reconstruction illumination light, and the light emitted from the spatial light modulator 314 is only effective reconstruction light that does not contain unnecessary 0th order light. This allows the camera 341 to pick up a three-dimensional reconstructed image formed by the reproduced light 316 emitted from the spatial light modulator 314 .

The hologram image captured by the camera 341 in this way is input to the camera control/wavefront control unit 342 as an image 361. On the other hand, the drive signal 362 for instructing the imaging timing of the camera 341 is input to the camera control/wavefront control unit 342. is input to the camera 341 from . The camera control/wavefront control unit 342 evaluates the wavefront of the input image data, and sends a driving signal 368 to the measurement phase shifter 343 so as to improve the evaluation, thereby adjusting the phase of the light for measurement. is controlled and the reference light data 363 when controlled is output to the data holding unit 331 .

The image picked up by the camera 341 is sent to the camera control/wavefront analysis unit 342. On the other hand, the camera control/wavefront analysis is performed in synchronization with the drive signal sent from the spatial light modulator control unit 333 to the drive signal 329. A drive signal is sent from the analysis unit 342 to the camera 341 .
Thus, in the calibration device according to Application Example 2 as well, the reconstruction illumination light from the spatial light modulator 314 displaying the hologram image is irradiated, and the light emitted from the spatial light modulator 314 is unnecessary light. Only the effective reproduction light that does not contain the next light can be used.

<Application example 3>
Next, application example 3 will be described with reference to FIG. As described above, this holographic display uses the active reconstruction illumination optical system, and is only partially different from the passive reconstruction illumination optical system of Application Example 1 shown in FIG. Therefore, the different parts will be described, and the other similar configurations will be given reference numerals by adding 200 to the reference numerals given in FIG. 5, and description thereof will be omitted.

That is, in the holographic display using the active reproduction illumination optical system according to the application example 3, each path of the light 426 split by the light splitter 422 is provided with phase shifters 1 to n (471-1) for modulating the phase of light. 471-n), and grating sections 1 to n (424-1 to 424-n) are provided behind the respective phase shifters 1 to n (471-1 to 471-n). That is, in the holographic display according to the application example 3, the vertical emission type OPA 413, in addition to the light input unit 430, the light splitter 422, and the grating units 424-1 to 424-n, adjusts the phase of light for each path. An adjustable phase shifter 471 is provided. In this phase shifter 471, the phase of light is adjusted by a driving signal 470 output from the phase shifter control section 445 based on the calibration data and the optical deflection control data 469 from the data holding section 431, thereby forming an active type. A configuration is formed.
In the holographic display according to this application example 3 as well, the reconstruction illumination light of the spatial light modulator 414 displaying the hologram image is irradiated, and the light emitted from the spatial light modulator 414 is also zero-order light, which is unnecessary light. It can be only effective reproduction light that does not contain light.

<Application example 4>
Next, application example 4 will be described with reference to FIG. As described above, this apparatus is a calibration apparatus using the active reconstruction illumination optical system 1, and the calibration apparatus using the passive reconstruction illumination optical system of Application Example 2 shown in FIG. are different, the different parts will be described, and other similar configurations will be given reference numerals by adding 200 to the reference numerals given in FIG. 6, and description thereof will be omitted.
That is, the calibration apparatus using the active type reproduction illumination optical system according to the application example 4 has phase shifters 1 to n (571-1) for modulating the phase of the light in each path of the light 526 split by the light splitter 522. 571-n), and grating sections 1 to n (524-1 to 524-n) are provided after the respective phase shifters 1 to n (571-1 to 571-n). That is, in the calibration device according to Application Example 4, the vertical emission type OPA 513 includes the optical input section 530, the optical splitter 522, the grating sections 524-1 to 524-n, the distributor 521, the measuring phase shifter 543, and the measuring In addition to the optical waveguide 544, each path has a phase shifter 571 capable of adjusting the phase of light.

In the calibration device according to Application Example 4 as well, the spatial light modulator 514 displaying the hologram image is irradiated with the reconstruction illumination light, and unnecessary zero-order light that has not been modulated by the spatial light modulator 514 reaches the air layer. Since no light is emitted, the light emitted from the spatial light modulator 514 can be only effective reproduced light that does not contain unnecessary 0th order light.

<Application example 5>
Next, application example 5 will be described with reference to FIG. As described above, this apparatus is a calibration apparatus using the active reconstruction illumination optical system 2, and has substantially the same configuration as the calibration apparatus using the active reconstruction illumination optical system 1 of Application Example 4. However, in Application Example 4, the light for measurement is split by the splitter 521 to separately form a path for measurement, whereas in Application Example 5, the optical splitter 622 splits the light. It differs in that one of the light paths (eg the nth channel) is assigned to the light path for measurement. Therefore, in FIG. 9, reference numerals obtained by adding 100 to the reference numerals given in FIG. 8 are assigned to members corresponding to application example 4 and application example 5, and description thereof is omitted.

In the calibration apparatus according to Application Example 5 as well, the spatial light modulator 614 displaying the hologram image is irradiated with the reconstruction illumination light, and unnecessary zero-order light that has not been modulated by the spatial light modulator 614 enters the air layer. Since no light is emitted, the light emitted from the spatial light modulator 614 can be only effective reproduced light that does not contain unnecessary 0th order light.

The reproduction illumination light irradiation device for holography and the holographic display of the present invention are not limited to the above-described embodiments, and other various modifications are possible. For example, the type of vertical emission type OPA is not limited to the channel type shown in FIG. It is also possible to
Further, in the above embodiments, a liquid crystal display element is used as the spatial light modulator, but for example, a DMD (digital mirror device) or the like can be used as the reflective spatial light modulator shown in FIG. is.

10 holographic display 11, 211, 311, 411, 511, 611 laser light source 12, 12a, 112a, 212, 312, 412, 512, 612, 812a incident light 13, 13a, 113a, 213, 313, 413, 513, 613 vertical emission type OPA
14, 14a, 114a, 214, 314, 414, 514, 614, 814a Spatial Light Modulators (SLM)
15, 215, 315, 415, 515, 615 Emitted light (reproduction illumination light)
16, 16a, 116a, 216, 316, 416, 516, 616, 816a Reproduced light 17, 217, 417, 850 Three-dimensional video (reproduced image)
18, 18a, 118a, 818 Zero order light 20, 820 Observer 22, 222, 322, 422, 522, 622 Optical splitter 23, 471, 471-1 to 471-n, 571, 571-1 to 571-n, 671, 671-1 to 671-n phase shifter 24, 54, 154 grating 51 substrate 52, 152 lower clad 53, 153 core 55, 155 upper clad 54a, 154a, 224, 324, 424-1 to 424-n, 524 -1 to 524-n, 624-1 to 624-n, 854 Grating part 215, 367, 415, 567, 615 Emitted light 226, 326, 426, 526, 626 Split light 227 3DCG data, reference light data 228 , 428 hologram data 229, 329, 362, 368, 429, 470, 529, 562, 568, 629, 662, 668, drive signal 230, 330, 430, 530, 630 light input section 231, 331, 431, 531, 631 data holding unit 232, 432 hologram generation unit 233, 333, 433, 533, 633 spatial light modulator control unit 321, 521 distributor 327, 527 light to be measured 341, 541, 641 camera 342, 542, 642 camera control Wavefront controllers 343, 543 Phase shifters for measurement 344, 544 Optical waveguides for measurement 361, 561, 661 Image 363 Reference light data 364, 564, 664 Pattern for measurement 365, 565 Light for measurement 366, 466, 566, 666 Phase-modulated light 469 calibration data, optical deflection control data 427 3DCG data, reference light data, calibration data 445 phase shifter controller 563, 663 reference light data, calibration data 819 field lens 840 diffracted light from optical waveguide grating

Claims (8)

a light source;
The light from the light source is incident from the side, and the 0th order light of the incident light is repeatedly internally reflected on the front surface and the back surface and propagated to the side opposite to the incident side of the light, According to the hologram pattern displayed on the spatial light modulation element arranged in close contact with the front surface or the back surface, the light that is used as the reproduction light from the light incident on the interface with the spatial light modulation element from the inside is selected. , and an optical phased array that emits to an air layer outside the surface side,
The optical phased array has a grating structure extending in the propagation direction of the 0th order light, and is configured to diffract the light incident on the optical phased array at a predetermined angle in the front surface direction and the back surface direction. A reproduction illumination light irradiation device for holography, characterized in that: 2. The holographic reconstruction illumination light irradiation device according to claim 1, wherein the grating period of the grating structure satisfies the following formula (A).
|n _e −λ/Λ|>1 (A)
is the wavelength of the incident light, _.LAMBDA . is the grating period, and ne is the effective refractive index of the grating. 3. A holographic display comprising the reproduction illumination light irradiation device for holography according to claim 1, and the spatial light modulation element. 4. A holographic display according to claim 3, wherein said spatial light modulating element is a transmissive spatial light modulating element that is in close contact with said surface of said optical phased array. Of the diffracted light from the optical phased array side, the 0th order light incident on the interface between the optical phased array and the transmissive spatial light modulation element from the inside is totally reflected at the interface. light used as reproduction light that enters from the inside passes through the spatial light modulation element and is emitted to the air layer on the surface side of the optical phased array. 5. The holographic display of claim 4. 4. A holographic display according to claim 3, wherein said spatial light modulating element is a reflective spatial light modulating element closely attached to said back surface of said optical phased array. Of the diffracted light from the optical phased array side, the 0th order light incident on the interface between the optical phased array and the reflective spatial light modulator from the inside is totally reflected at the interface. light used as reproduction light that enters from the inside of the optical phased array is reflected by the spatial light modulation element and emitted from the surface side of the optical phased array to the air layer. 7. The holographic display of claim 6. A holographic display as claimed in any one of claims 3 to 7, characterized in that the optical phased array is either passive or active.

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