JP6831987B2 - Holography display device - Google Patents

Description

The present invention relates to a holographic display device that displays a stereoscopic reproduction image using an electronically generated hologram (interference fringe).

Reproduction of holography by an electronic display device The problem with electronic holography is that the resolution of the device is overwhelmingly low compared to classical holograms. As one method to alleviate this problem, we have proposed a method of time-division multiplexing of the reproduced image using a device with a high frame rate. In the proposed method, by switching a laser diode (LD) light source capable of high-speed response, time division multiplexing of the reproduced image is performed without using complicated optical systems and moving parts as in the conventional method, and the resolution is expanded. be able to. In order to confirm the principle of the proposed method, we report a display system (holography display device) that has been prototyped using a spatial light modulator (SLM) and has a resolution that is approximately four times larger. Specifically, as shown in FIG. 4A, the four light sources LD1 to LD4 arranged at intervals in the x-axis (horizontal) direction are sequentially switched to convert the lit light into parallel light by a collimator lens. After that, it is incident on one SLM and spatially light-modulated. A multiplexed Fourier transform image can be obtained by Fourier transforming the spatially light-modulated light with a Fourier lens and arranging them on a Fourier plane (virtual plane for image formation) without gaps. As a result, the viewing angle can be expanded by 4 times and high-quality hologram display can be performed by multiplexing the horizontal resolution by 4 times with a simple configuration that does not use moving parts such as a galvano mirror. (See, for example, Non-Patent Document 1). The distance from the LD light sources LD1 to LD4 to the collimator lens and the distance from the collimator lens to the SLM are f _C, and the distance from the SLM to the Fourier lens and the distance from the Fourier lens to the Fourier surface are f ₁ .

"Light Source Switching Time-Division Holographic Display", Atsushi Matsuda, Kyoji Matsushima, Journal of the Institute of Electronics, Information and Communication Engineers 2013/3 Vol.J96-D No.3 pp.381-388

The inconvenience of the holographic display device of Non-Patent Document 1 will be described with reference to FIGS. 4 (a) and 4 (b). In FIG. 4A, since the four light sources LD1, LD2, LD3, and LD4 are provided at intervals in the x-axis (horizontal) direction, the number of multiplexings is M = 4 in the x-axis (horizontal) direction. The y-axis (vertical) direction N = 1. Further, in FIG. 4A, the light of the light source LD1 irradiates the Fourier plane (virtual plane for image formation) at the position # 1 (the position at the right end when viewed from the light source side), and this is the image to be reproduced. This is the first-order diffracted light. The second-order diffracted light irradiates the Fourier surface (virtual surface for image formation) at the position # 2 (the second position from the right end when viewed from the light source side) adjacent to the Fourier surface on which the first-order diffracted light is irradiated. Will be done. The irradiation of the second-order diffracted light is generated because the pixels of the SLM are rectangular. Similarly, the Fourier plane (virtual plane for image formation) at the position # 3 (the third position from the right end when viewed from the light source side) is irradiated with the third-order diffracted light, and the position # 4 (from the light source side). The Fourier plane (virtual plane for image formation) located at the fourth position from the right end is irradiated with the fourth-order diffracted light. Further, when the other light sources LD2 to LD4 are sequentially turned on, as shown in FIG. 4B, diffracted light other than the primary diffracted light which is an image to be reproduced is irradiated as in the light source LD1. become. For example, in the case of the light source LD2, in addition to the first-order diffracted light, three diffracted lights of -1st-order diffracted light, second-order diffracted light, and third-order diffracted light are irradiated. Further, in the case of the light source LD3, in addition to the primary diffracted light, three diffracted lights of the second-order diffracted light, the -1st-order diffracted light, and the second-order diffracted light are irradiated. Further, in the case of the light source LD4, in addition to the first-order diffracted light, the third-order diffracted light, the second-order diffracted light, and the -1st-order diffracted light are irradiated. In this way, when three diffracted lights are irradiated in addition to the primary diffracted light, the three diffracted lights are superimposed on the primary diffracted light to reproduce the image, so that the reproduced multiplexed image is clear. The inconvenience of not being able to project occurs.

An object of the present invention in view of the above situation is to provide a holographic display device capable of clearly projecting a multiplexed image.

The holographic display device of the present invention is switchable and is arranged so that the polarization direction of the light emitted from one adjacent light source and the polarization direction of the light emitted from the other adjacent light source are different. The light source, a spatial light modulator that spatially photomodulates the light emitted by sequentially switching the plurality of light sources, and a Fourier conversion means that Fourier transforms the spatially light-modulated light by the spatial light modulator. The Fourier transformed means is provided with an image forming virtual surface having a plurality of corresponding regions provided corresponding to each light source in order to irradiate the Fourier transformed light to form a stereoscopic image. It is a polarizing means configured to transmit light so as to irradiate the virtual surface or to block light so as not to irradiate the virtual surface, and includes a plurality of polarization areas provided corresponding to each light source, and each of the polarizations. The area is characterized by comprising a polarizing means configured to transmit light in the polarization direction of the corresponding light source and to block light in a polarization direction different from the polarization direction.

According to the above configuration, the light of the light source that is sequentially turned on by switching is spatially light-modulated by the spatial light modulator. The spatial light-modulated light is Fourier-transformed by the Fourier transform means, the Fourier-transformed light is sequentially irradiated to the virtual surface for image formation, and a plurality of lights corresponding to the number of light sources are superimposed on the virtual surface. By doing so, a multiplexed stereoscopic image is projected. Since the polarization direction of the light emitted from one of the adjacent light sources among the plurality of light sources is different from the polarization direction of the light emitted from the other adjacent light source, the polarization direction thereof is changed. By using the polarization means set accordingly, the light from one light source passes through the polarization area corresponding to the one light source and is applied to the corresponding region, but the polarization adjacent to the polarization area. Areas (eg, polarized areas corresponding to the other light source) are shaded. Similarly, light from the other light source passes through the polarization area corresponding to the other light source and irradiates the corresponding region, but corresponds to the polarization area adjacent to the polarization area (for example, one polarization area). It is shielded from light in the polarized area). Therefore, of the light from each light source, the first-order diffracted light that is the image to be reproduced passes through the polarization area corresponding to the light source and irradiates the corresponding area of the virtual surface, but other light adjacent to this first-order diffracted light. Since the diffracted light is blocked by other adjacent polarizing areas, the other diffracted light adjacent to the primary diffracted light is not superimposed on the virtual surface. Therefore, it is possible to prevent the reproduced image from becoming unclear.

Further, the holographic display device of the present invention includes a plurality of switchable light sources arranged so as to be adjacent to each other, and a spatial light modulator that spatially photomodulates light emitted by sequentially switching the plurality of light sources. A plurality of Fourier conversion means for Fourier-converting space light-modulated light by the spatial light modulator and a plurality of light sources corresponding to the light sources are provided in order to irradiate the Fourier-converted light with the Fourier conversion means to form a stereoscopic image. The virtual surface for image formation having the corresponding corresponding region is different from the polarization direction of the light emitted from one of the plurality of adjacent light sources and the polarization direction of the light emitted from the other light source. It is provided with a first polarization means for polarizing the light from the plurality of light sources, and is configured to transmit the Fourier-transformed light so as to irradiate the virtual surface or to block the light so as not to irradiate the virtual surface. It is a polarization means and includes a plurality of polarization areas provided corresponding to each of the light sources, and each of the polarization areas transmits light in the polarization direction of the corresponding light source and has a polarization direction different from the polarization direction. It is characterized by including a second polarizing means configured to block light.

According to the above configuration, the light of the light source that is sequentially turned on by switching is spatially light-modulated by the spatial light modulator. Spatial light-modulated light is Fourier-transformed by a Fourier transform means, and the Fourier-transformed light is sequentially applied to a virtual surface for image formation, and a plurality of lights corresponding to a light source are superimposed on the virtual surface. A stereoscopic image is projected with. Then, the first polarizing means is configured so that the polarization direction of the light emitted from one of the plurality of adjacent light sources and the polarization direction of the light emitted from the other light source are different. By using the second polarization means set according to the polarization direction, the light from one light source is transmitted through the polarization area corresponding to the one light source and irradiated to the corresponding corresponding region. The polarization area adjacent to the polarization area (for example, the polarization area corresponding to the other light source) is shielded from light. Similarly, light from the other light source passes through the polarization area corresponding to the other light source and irradiates the corresponding region, but corresponds to the polarization area adjacent to the polarization area (for example, one polarization area). It is shielded from light in the polarized area). Therefore, of the light from each light source, the first-order diffracted light that is the image to be reproduced passes through the polarization area corresponding to the light source and irradiates the corresponding area of the virtual surface, but other light adjacent to this first-order diffracted light. Since the diffracted light is blocked by other adjacent polarizing areas, the other diffracted light adjacent to the primary diffracted light is not superimposed on the virtual surface. Therefore, it is possible to prevent the reproduced image from becoming unclear.

Further, in the holographic display device of the present invention, the polarization direction of the light emitted from the one light source and the polarization direction of the light emitted from the other light source are different by 90 degrees, and the adjacent polarized light is obtained. It is preferable that the polarization directions set in the area are set so as to be different by 90 degrees.

As in the above configuration, the polarization direction of the light emitted from one light source and the polarization direction of the light emitted from the other light source are different by 90 degrees, and the polarization set in the adjacent polarization areas. By setting the directions to be different by 90 degrees, it is possible to reliably block the light that the virtual surface does not want to irradiate, and to reliably transmit the light that the virtual surface wants to irradiate.

Further, in the holography display device of the present invention, it is preferable that the plurality of corresponding regions are rectangular and are arranged without gaps along the direction in which the plurality of light sources are arranged.

As in the above configuration, since the plurality of corresponding regions are rectangular and are arranged without gaps along the direction in which the plurality of light sources are arranged, there is no trouble that a part of the image is chipped.

According to the present invention, each polarization area transmits light in the polarization direction of the corresponding light source, and a polarization means (or second polarization means) configured to block light in a polarization direction different from the polarization direction. By providing the device, it is possible to provide a holographic display device capable of clearly projecting superimposed and multiplexed images.

(A) is a schematic view of the holography display device of the present invention, and (b) is an explanatory view showing a display state of a Fourier transform image displayed by the device of FIG. 1 (a). It is the schematic of the holography display device of the 2nd Embodiment. (A) to (h) show other embodiments, (a) is a front view showing the polarization directions of a total of six light sources arranged in two upper and lower stages, and (b) is from the light source of FIG. 3 (a). The front view of the polarization mask for polarizing the irradiated and Fourier-transformed light by the Fourier lens, (c) shows that the lower light source is shifted by one in the horizontal direction with respect to the upper light source of FIG. 3 (a). A front view showing the polarization directions of the six light sources in the state, (d) is a front view of a polarization mask for polarizing the light emitted from the light source of FIG. 3 (c) and Fourier transformed by the Fourier lens, (e). ) Is a front view showing a state in which the polarization direction of the light source of FIG. 3A is tilted by 45 degrees, and FIG. 3F is a polarization of light irradiated from the light source of FIG. 3E and transformed by a Fourier lens. The front view of the polarization mask for the purpose, (g) is a front view showing the polarization directions of 15 light sources arranged so that the number is smaller toward the upper side, and (h) is irradiated from the light source of FIG. 3 (g). It is a front view of the polarization mask for polarized light which was Fourier transformed by a Fourier lens. (A) is a schematic view of a conventional holography display device, and (b) is an explanatory diagram showing a display state of a Fourier transform image displayed by the device of FIG. 4 (a).

FIG. 1A shows a schematic view of a switching type time-division holography display device 1 (hereinafter referred to as a holography display device 1) of the present invention. The holography display device 1 is composed of four switchable LD (laser diode) light sources LD1, LD2, LD3, LD4 arranged at equal intervals on the x-axis and LD light sources LD1, LD2, LD3, LD4. A collimator lens for converting the light from the collimator lens into parallel light, an SLM (Spatial Light Modulator) that is a spatial light modulator that spatially modulates the light from the collimator lens, a Fourier lens that Fourier-converts the light from the SLM, and Fourier. A plurality (4) corresponding regions (not shown, but will be described later) are provided corresponding to each LD light source LD1 or LD2 or LD3 or LD4 in order to irradiate the Fourier-transformed light with a lens to form a stereoscopic image. It includes a virtual surface for image formation (corresponding to the Fourier plane of FIG. 1A) having a first corresponding region to a fourth corresponding region corresponding to four polarization areas. As described above, since the four LD light sources LD1, LD2, LD3, and LD4 are provided so as to be adjacent to each other at equal intervals in the x-axis direction (horizontal direction), the number of multiplexings is in the x-axis direction (horizontal direction). ) M = 4 and the y-axis (vertical) direction N = 1. The distance from the LD light sources LD1 to LD4 to the collimator lens and the distance from the collimator lens to the SLM are f _C, and the distance from the SLM to the Fourier lens and the distance from the Fourier lens to the Fourier surface are f ₁ .

As the light source, an LD light source that emits light having high brightness and high directivity, or an LED light source that irradiates a predetermined range can be used. Although not shown, a switching power supply device for switching each LD light source LD1 or LD2 or LD3 or LD4 is provided so that only one LD light source of the LD light sources LD1, LD2, LD3, LD4 is turned on instantaneously. ing. The order in which these LD light sources LD1, LD2, LD3, and LD4 are turned on may be any order.

A polarizing mask, which is a polarizing means configured to transmit the Fourier-transformed light as described above so as to irradiate the virtual surface or to block light so as not to irradiate the virtual surface, is arranged on the Fourier surface (virtual surface). There is. Each polarization area of the polarization mask is configured to transmit light in the polarization direction of the corresponding LD light source and to block light in a polarization direction different from the polarization direction.

The polarization directions of the four LD light sources LD1, LD2, LD3, and LD4 are set respectively. Specifically, the polarization direction of the first LD light source LD1 located at the right end in the x-axis (horizontal) direction in the drawing is the horizontal (x-axis) direction. Further, in the drawing view, the polarization direction of the second LD light source LD2, which is the second from the right end in the x-axis (horizontal) direction, is the vertical (y-axis) direction in which the angle is 90 degrees different from the horizontal direction (orthogonal to the horizontal direction). Further, the polarization direction of the third LD light source LD3 located third from the right end in the x-axis (horizontal) direction in the drawing is the horizontal (x-axis) direction. Further, the polarization direction of the fourth LD light source LD4 located fourth from the right end in the x-axis (horizontal) direction in the drawing view is the vertical (y-axis) direction in which the angle is 90 degrees different from the horizontal direction (orthogonal to the horizontal direction). In this way, the polarization directions of the LD light sources LD1 and LD2 or LD2 and LD3 or LD3 and LD4 that are adjacent to each other in the x-axis (horizontal) direction are set to be different by 90 degrees.

The polarizing mask is formed in a rectangular shape (horizontally elongated rectangular shape in FIG. 1A) having a size corresponding to a region irradiated from each LD light source LD1 or LD2 or LD3 or LD4 via a Fourier lens. The polarization areas 11, 12, 13, and 14 are arranged side by side in the x-axis (horizontal) direction without any gaps. The polarization directions of these four polarization areas 11, 12, 13, and 14 are set to be 90 degrees different in the polarization areas adjacent to each other. Therefore, each polarization area of the polarization mask is configured to transmit linearly polarized light vibrating in a specific direction and to block linearly polarized light vibrating in a direction 90 degrees different from the specific direction.

In FIG. 1A, the first polarized area 11 at the leftmost position # 1 in the x-axis direction in the drawing view of the four polarized areas 11, 12, 13, and 14 is irradiated from the lit LD light source LD1. It shows the state in which the emitted light is emitted through the collimator lens, SLM, and Fourier lens. This light is the first-order diffracted light that becomes the image to be reproduced, and since the polarization direction of the first polarization area 11 is the same horizontal direction as the polarization direction of the LD light source LD1, the first-order diffracted light passes through the first polarization area 11. Then, the corresponding region (first corresponding region) of the Fourier plane is irradiated. Further, the second polarized light is irradiated to the second polarized area 12 at the position # 2 on the right side of the first polarized area 11 in the x-axis direction, but the polarization direction of the LD light source LD1 is the second polarized area with respect to the horizontal direction. Since the polarization direction of the 12 is a vertical direction (different direction), the second-order diffracted light is blocked by the second polarization area 12. Further, since the third polarization area 13 on the right side of the second polarization area 12 in the x-axis direction is irradiated with the third-order polarized light, the polarization direction of the third polarization area 13 is the same horizontal direction as the polarization direction of the LD light source LD1. The third-order diffracted light passes through the third polarization area 13 and is irradiated to the corresponding region (third corresponding region) of the Fourier plane, and the third-order diffracted light is the first polarized area 11 to which the first-order diffracted light is irradiated. Since the light intensity is weaker than the diffracted light (here, the second-order diffracted light) irradiated to the second polarization area 12 adjacent to the first-order polarized light, even if the third-order diffracted light is superimposed on the first-order diffracted light, the reproduced image becomes unclear. There is no problem. Further, the fourth polarized light is irradiated to the fourth polarized area 14 on the right side of the third polarized area 13 in the x-axis direction, but the polarization direction of the LD light source LD1 is the polarization direction of the fourth polarized area 14 with respect to the horizontal direction. Is in the vertical direction (different directions), so that the fourth-order diffracted light is blocked by the fourth polarization area 14.

Next, when the LD light source LD2 whose polarization direction is the vertical direction is turned on, the light emitted from the turned on LD light source LD2 passes through the collimator lens, SLM, and Fourier lens to the right of the left end in the x-axis direction in the drawing view. Since the second polarization area 12 at position # 2 is irradiated with the primary diffraction light that is the image to be reproduced, and the polarization direction of the second polarization area 12 is the same as the polarization direction of the LD light source LD2, the primary diffraction light is It passes through the second polarization area 12 and irradiates the corresponding region (second corresponding region) of the Fourier plane. The first polarized light area 11 and the third polarized light area 13 adjacent to the second polarized light area 12 are irradiated with the -1st polarized light and the 2nd polarized light, but the polarization direction of the LD light source LD2 is second with respect to the vertical direction. Since the polarization directions of the first polarization area 11 and the third polarization area 13 are horizontal (different directions), the first-order and second-order diffraction light are shielded from light in the first polarization area 11 and the third polarization area 13. .. Further, in the drawing view, the fourth polarized light at the position # 4 at the right end in the x-axis direction is irradiated with the third-order diffracted light, and the third-order diffracted light is adjacent to the second polarized light area 12 to which the first-order diffracted light is irradiated. Since the light intensity is weaker than the diffracted light (here, the -1st-order diffracted light and the 2nd-order diffracted light) irradiated to the 1st and 3rd polarized light areas 11, even if the 3rd-order diffracted light is superimposed on the 1st-order diffracted light, The reproduced image does not become blurry and does not matter.

Next, when the LD light source LD3 whose polarization direction is the horizontal direction is turned on, the light emitted from the turned on LD light source LD3 is the third from the left end in the x-axis direction in the drawing view via the collimator lens, SLM, and Fourier lens. Since the third polarization area 13 at position # 3 is irradiated with the primary diffraction light that is the image to be reproduced and the polarization direction of the third polarization area 13 is the same horizontal direction as the polarization direction of the LD light source LD3, the primary diffraction light is It passes through the third polarization area 13 and is irradiated to the corresponding region (third corresponding region) of the Fourier plane. The second polarized light area 12 and the fourth polarized light area 14 adjacent to each other of the third polarized light area 13 are irradiated with the -1st polarized light and the 2nd polarized light, but the polarization direction of the LD light source LD2 is the second with respect to the horizontal direction. Since the polarization directions of the second polarization area 12 and the fourth polarization area 14 are vertical directions (different directions), the first-order and second-order diffraction light are shielded by the second polarization area 12 and the fourth polarization area 14. .. Further, in the drawing view, the second polarized light is irradiated to the first polarized light area 11 at the left end position # 1 in the x-axis direction, and the second polarized light is the third polarized light area 13 to which the first polarized light is irradiated. Since the light intensity is weaker than the diffracted light (here, the -1st-order diffracted light and the 2nd-order diffracted light) radiated to the adjacent 2nd and 4th polarized light areas 12, the 2nd-order diffracted light is superimposed on the 1st-order diffracted light. However, the reproduced image is not blurred and does not matter.

Next, when the LD light source LD4 is turned on, the light emitted from the turned on LD light source LD4 passes through the collimator lens, the SLM, and the Fourier lens into the fourth polarization area 14 at the right end position # 4 in the x-axis direction in the drawing view. Since the primary diffracted light that is the image to be reproduced is irradiated and the polarization direction of the fourth polarization area 14 is the same as the polarization direction of the LD light source LD3, the first diffracted light passes through the fourth polarization area 14 and Fourier. The corresponding area of the surface (fourth corresponding area) is irradiated. Further, the third polarized light is irradiated to the third polarized area 13 at the position # 3 on the left side of the fourth polarized area 14 in the x-axis direction, but the polarization direction of the LD light source LD4 is the third polarized light with respect to the vertical direction. Since the polarization direction of the area 13 is the horizontal direction (different direction), the -1st-order diffracted light is blocked by the third polarization area 13. Further, since the second polarized light on the left side of the third polarized area 13 is irradiated with the secondary polarized light and the polarization direction of the second polarized area 12 is the same as the polarization direction of the LD light source LD4, − The second-order polarized light passes through the second polarization area 12 and is irradiated to the corresponding region (second corresponding region) of the Fourier plane, and the second-order diffracted light is the fourth polarized area 14 to which the first-order diffracted light is irradiated. Since the light intensity is weaker than the diffracted light (here, the -1st-order diffracted light) irradiated to the third polarized light area 13 adjacent to the first-order polarized light, the reproduced image is unclear even if the second-order diffracted light is superimposed on the first-order diffracted light. It doesn't become a problem. Further, the first polarized light area 11 on the left side in the x-axis direction of the second polarized light area 12 is irradiated with the third-order polarized light, but the polarization direction of the LD light source LD4 is the polarization of the first polarized light area 11 with respect to the vertical direction. Since the directions are horizontal (different directions), the third-order diffracted light is blocked by the first polarization area 11.

As described above, FIG. 1 (b) shows the state of the light (image) irradiated on the Fourier surface when each LD light source LD1 or LD2 or LD3 or LD4 is sequentially turned on. In FIG. 1 (b), the light (image) adjacent to the first-order refracted light is shielded, and the light (image) having a weak light intensity emitted away from the first-order diffracted light, and in the figure, the second-order diffracted light and the third-order diffracted light. However, even if these lights are superimposed on the first-order diffracted light, the reproduced image does not become unclear, which is not a problem. Therefore, by providing a polarizing mask on the Fourier surface, adjacent light (light that makes the image unclear) can be shielded, so that four lights sequentially irradiated on the Fourier surface are superimposed and multiplexed. It can be projected clearly. The image plane for forming an image by irradiating the light from the Fourier plane is omitted. Incidentally, when a high-speed liquid crystal shutter is used instead of the polarizing mask of the present invention in order to remove diffracted light other than the primary diffracted light, a frame within a predetermined range exists around an effective area that operates as a shutter. This is a fatal drawback and cannot be used, especially when the number of multiplexings is increased so that a clearer image is projected.

The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

In the above embodiment, a transmissive SLM using a liquid crystal is used as the spatial light modulator, but in addition to this, a reflective liquid crystal LCOS or a reflective DMD (Digital Micromirror Device) may be used as the SLM. This DMD has a structure in which more than 2 million micromirrors are spread on an integrated circuit, and one mirror corresponds to one pixel. The DMD configured in this way modulates the incident light by changing the inclination of the mirror according to the signal.

Further, in the above-described embodiment, a light source having a fixed polarization direction is used, but as shown in FIG. 2, a first for polarizing the light emitted from the four LD light sources LD1 to LD4 in a desired direction. The first polarization mask, which is one polarization means, may be provided at a position on the collimator lens side from the LD light sources LD1 to LD4. In this case, a second polarization mask, which is a second polarization means, is provided on the Fourier plane. Since the state of the light (image) emitted to the Fourier surface when each LD light source LD1 or LD2 or LD3 or LD4 is turned on is the same as in FIG. 1B, the description thereof will be omitted. Further, the horizontal viewing area angle of the image projected on the image plane 15 may be enlarged by performing the Fourier transform again with the Fourier lens 2 provided behind the Fourier plane in FIG. The distance from the second polarizing mask to the Fourier lens 2 and the distance from the Fourier lens 2 to the image plane 15 are f ₂ . Other configurations not described are the same as those in FIG. 1A, and the description is omitted.

Further, in the above embodiment, a plurality of light sources are provided in one horizontal direction (specifically, four, but may be two, three, or five or more), but a plurality (2) in the vertical direction. (More than one) may be provided, or a plurality (two or more) may be provided in both the horizontal direction and the vertical direction. For example, FIGS. 3 (a), (c), (e), and (g) show four examples. 3 (b), (d), (f), and (h) show a polarizing mask 20 which is a polarizing means for the light source of FIGS. 3 (a), (c), (e), and (g). .. In FIG. 3A, the light sources are arranged in two upper and lower stages, three light sources are arranged in each stage, and a total of six light sources 21, 22, 23, 24, 25, and 26 are arranged. In these light sources 21, 22, 23, 24, 25, and 26, the polarization directions of adjacent light sources in the horizontal direction and the vertical direction are different by 90 degrees. For example, in the drawing, the polarization direction of the upper light source 21 among the light sources 21 and 24 arranged above and below the right end is horizontal (left and right in the figure), and the polarization direction of the lower light source 24 is perpendicular (up and down in the figure). ) It is in the direction. The arrangement of the polarization areas constituting the polarization mask 20 of FIG. 3B is the same as that of the light source of FIG. 3A, but the positions of the polarization areas are symmetrical with respect to the positions of the corresponding light sources. Since the positions are vertically reversed, the polarization directions are set to different directions by 90 degrees as a result. Further, FIG. 3C shows a state in which the lower light sources 24, 25, and 26 are displaced from the upper light sources 21, 22, and 23 by one light source on the left side in the drawing. In this arrangement, the polarization mask 20 in FIG. 3D is arranged in the same arrangement as the light source in FIG. 3C and the polarization direction is also set in the same position because the positions are the same when the positions are symmetrically reversed horizontally and vertically. ing. Further, in FIG. 3E, the arrangement of the light sources is the same as that in FIG. 3A, and the polarization direction is set to the polarization direction inclined by 45 degrees with respect to the vertical direction. The polarization mask 20 of FIG. 3 (f) reverses the arrangement of the light source of FIG. 3 (e) symmetrically and to the upper limit object, and as a result, has the same arrangement as the light source, but the polarization direction is set to a direction different by 90 degrees. Has been done. Further, in FIG. 3 (g), three light sources 21, 22, 23 are arranged in the upper stage, five light sources 24 to 28 are arranged in the middle stage, and seven light sources 29 to 35 are arranged in the lower stage. It is configured in a trapezoidal shape (may be a pyramid type) in which the number of light sources increases toward the lower side. In the polarizing mask 20 of FIG. 3 (h), since the arrangement of the light sources is symmetrical, only the light source of FIG. 3 (g) and the top and bottom are set to be reversed.

1 ... Holography display device, 11, 12, 13, 14 ... Polarized area, 15 ... Image plane, 20 ... Polarized mask (polarizing means), 21-35 ... Light source, LD1 to LD4 ... LD light source

Claims (4)

Switching possible, and, in one of the light sources and the other adjacent and a light source, the one of the light irradiated to the polarization direction of the light emitted from the light source from the other light source polarization direction is different so arranged A plurality of light sources, a spatial light modulator that spatially photomodulates the light emitted by sequentially switching the plurality of light sources, and a Fourier conversion means that Fourier transforms the spatially light-modulated light by the spatial light modulator. And a virtual surface for image formation having a plurality of corresponding regions provided corresponding to each of the light sources in order to irradiate the light Fourier-transformed by the Fourier transform means to form a stereoscopic image.
Transmitted through the Fourier transform light to illuminate the virtual surface, or a configured polarizing means so as to shield so as not irradiated, polarization area provided multiple corresponding to each light source Each of the polarization areas is provided with a polarization means configured to transmit light in the polarization direction of the corresponding light source and to block light in a polarization direction different from the polarization direction. Holography display device. A plurality of switchable light sources arranged so as to be adjacent to each other, a spatial light modulator that spatially photomodulates the light emitted by sequentially switching the plurality of light sources, and a spatial light modulator that spatially photomodulates the light. For image formation having a Fourier conversion means for Fourier-converting the light and a plurality of corresponding regions provided corresponding to each light source in order to irradiate the light Fourier-converted by the Fourier conversion means to form a stereoscopic image. The light from the plurality of light sources is polarized so that the polarization direction of the light emitted from one of the plurality of adjacent light sources and the polarization direction of the light emitted from the other light source are different from the virtual surface. With a first light source,
Transmitted through the Fourier transform light to illuminate the virtual surface, or a configured polarizing means so as to shield so as not irradiated, polarization area provided multiple corresponding to each light source Each of the polarization areas is provided with a second polarization means configured to transmit light in the polarization direction of the corresponding light source and to block light in a polarization direction different from the polarization direction. A holographic display device characterized by. The polarization direction of the light emitted from the one light source and the polarization direction of the light emitted from the other light source are different by 90 degrees, and the polarization area corresponding to the one light source and the other light source. The holographic display device according to claim 1 or 2, wherein the polarization directions set in the polarization area corresponding to the above are set to be different by 90 degrees. The holography display device according to any one of claims 1 to 3, wherein the plurality of corresponding regions are rectangular and are arranged without gaps along the direction in which the plurality of light sources are arranged.

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