JP4930071B2 - Display device - Google Patents

Description

  The present invention relates to a display device, and more particularly to a technology of a display device that displays a stereoscopic display using a virtual image.

  Conventionally, a stereoscopic display for performing a three-dimensional stereoscopic display has been proposed. In a head-up display that directly displays a display in the user's field of view, it is possible to perform three-dimensional stereoscopic display by superimposing virtual images at different reproduction positions. For example, when it is difficult to obtain a stereoscopic effect with only a single planar image, it is possible to obtain a stereoscopic effect by superimposing a plurality of planar images. In addition, it is possible to give a sense of depth to an image by superimposing images with different brightness. Conventionally, in order to obtain virtual images at different reproduction positions, a technique using a variable focus lens with a variable focus position has been proposed (see, for example, Patent Document 1). In addition, a technique using a plurality of display plates in a head-up display has been proposed (see, for example, Patent Document 2).

JP-A-9-297282 JP 2004-168230 A

  In the configuration proposed in Patent Document 1, the variable focus lens is used in an eyepiece optical system. In such a configuration, a large varifocal lens is required as a larger angle of view is adopted by increasing the range (eye range) where a virtual image can be seen. A large varifocal lens is difficult to manufacture, and a large varifocal lens is required, which makes it difficult to reduce the size and weight of the display device. When the display of a plurality of display boards is switched as in the technique proposed in Patent Document 2, a larger number of display boards is required as the number of focus positions that can be set is increased. If many display panels are required, the structure of the display device becomes complicated. In addition, since the focal length of the virtual image is fixed by the arrangement of the display board, it is very difficult to continuously change the position of the virtual image. Therefore, according to the conventional technology, there is a problem that it is difficult to perform high-quality stereoscopic display with a simple configuration. The present invention has been made in view of the above-described problems, and an object thereof is to provide a display device that enables high-quality stereoscopic display with a simple configuration.

In order to solve the above-described problems and achieve the object, according to the present invention, an image forming unit that forms an image;
An imaging optical system for reproducing an image formed by the image forming unit as a virtual image;
An imaging position variable unit that is provided on the incident side of the imaging optical system and changes a position of an image reproduced as a virtual image by the imaging optical system;
The imaging position variable unit includes a phase modulation unit which is the image forming unit that forms an image by modulating the phase of coherent light, and the phase modulation unit generates diffracted light according to a phase modulation pattern. While changing the phase of the light, an intermediate image is formed between the phase modulation unit and the imaging optical system, and the positions of the intermediate images sequentially switched by the image forming unit are changed. In addition, it is possible to provide a display device that performs stereoscopic display by changing the positions to be reproduced as a plurality of virtual images corresponding to the plurality of intermediate images by the imaging optical system.
According to still another preferable aspect of the present invention, the phase modulation unit sets in advance a phase modulation pattern for forming the intermediate image at different positions in a device that drives the phase modulation unit. A display device characterized by changing the position can be provided.
According to a preferred aspect of the present invention, it is possible to provide a display device characterized in that the phase modulation unit is a transmissive or reflective display panel including a plurality of liquid crystal elements corresponding to pixels. .
Further, according to a preferred embodiment of the present invention, the zero-order diffracted light and the first-order diffracted light are separated by causing the zero-order diffracted light from the phase modulation unit to travel straight and the first-order diffracted light to travel obliquely, A display device characterized in that the intermediate image is formed using first-order diffracted light can be provided.
Further, according to a preferred embodiment of the present invention, there is provided a prism provided between the phase modulation unit and the imaging optical system, and the zero-order diffracted light from the phase modulation unit is inclined by the refraction action of the prism. It is possible to provide a display device characterized in that the intermediate image is formed using the first-order diffracted light by causing the first-order diffracted light from proceeding in the direction and straightly traveling the first-order diffracted light from the phase modulation unit.

According to the present invention, the imaging position varying unit includes the phase modulation unit that is an image forming unit that forms an image by modulating the phase of the coherent light, and the phase modulation unit includes the diffracted light corresponding to the phase modulation pattern. It is possible to form an intermediate image between the phase modulation unit and the imaging optical system and to change the position of the intermediate image by changing the phase of the light while generating the above. The intermediate image formed by the phase modulation unit is observed as a virtual image through the imaging optical system. By changing the position of the intermediate image by the phase modulation unit, the position of the virtual image can be freely changed with a simple configuration. It is possible to adopt a large angle of view in the image forming optical system and to make the image forming position variable section small. In addition, since a plurality of display panels are not necessary, the display device can be configured simply. Thereby, a display device capable of high-quality stereoscopic display with a simple configuration can be obtained.

  In a preferred aspect of the present invention, the imaging position variable unit includes a relay optical system that forms an intermediate image between the image forming unit and the imaging optical system, and the relay optical system changes the position of the intermediate image. It is desirable to make it. The intermediate image formed by the relay optical system is observed as a virtual image through the imaging optical system. By changing the position of the intermediate image by the relay optical system, the position of the virtual image can be freely changed with a simple configuration.

  As a preferred aspect of the present invention, it is desirable that the relay optical system changes the position of the intermediate image by changing the position of the optical element constituting the relay optical system. By changing the position of the optical element, the position of the virtual image can be easily changed continuously.

  As a preferable aspect of the present invention, the imaging position variable unit includes a phase modulation unit that is an image forming unit that forms an image by modulating the phase of light, and the phase modulation unit corresponds to the phase modulation pattern. It is desirable to form an intermediate image between the phase modulator and the imaging optical system by changing the phase of the light while generating the diffracted light, and to change the position of the intermediate image. The intermediate image formed by the phase modulation unit is observed as a virtual image through the imaging optical system. By changing the position of the intermediate image by the phase modulation unit, the position of the virtual image can be freely changed with a simple configuration.

  Moreover, as a preferable aspect of the present invention, it is desirable to have a light source unit that supplies coherent light to the phase modulation unit. By using coherent light, good diffraction characteristics can be obtained in the phase modulation section.

  Moreover, as a preferable aspect of the present invention, it is desirable to have a partial transmission mirror that transmits part of the light from the imaging optical system and reflects other part of the light. Thereby, it can be set as the structure which can observe simultaneously the space and virtual image of the other side of a partial transmission mirror.

  Moreover, as a preferable aspect of the present invention, it is desirable that the partial transmission mirror has a display unit that is provided on a side different from the side where the imaging optical system is provided and displays an image. Thereby, the image displayed by the display unit and the virtual image can be superimposed and displayed.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a display device 10 according to Embodiment 1 of the present invention. The display panel 11 is an image forming unit that forms an image by modulating light supplied from a backlight, and is a transmissive liquid crystal panel. As the transmissive display panel, for example, a high temperature polysilicon TFT display panel (High Temperature Polysilicon; HTPS) can be used. Light from the display panel 11 enters the relay optical system 12. The relay optical system 12 forms an intermediate image 13 between the display panel 11 and the imaging optical system 14. The relay optical system 12 can be configured to use a condensing lens, for example.

  Light from the relay optical system 12 enters the imaging optical system 14. The imaging optical system 14 forms an image formed by modulation by the display panel 11. By forming the intermediate image 13 at a position closer to the imaging optical system 14 than the front focal point of the imaging optical system 14, the virtual image 16 of the intermediate image 13 is reproduced through the imaging optical system 14. As with the relay optical system 12, the imaging optical system 14 can be configured to use a condensing lens. The light from the imaging optical system 14 enters the partial transmission mirror 15. The partial transmission mirror 15 transmits a part of the light from the imaging optical system 14 and reflects the other part of the light. The partial transmission mirror 15 can be formed by coating a dielectric multilayer film on glass or the like which is a transparent member.

  Of the light from the imaging optical system 14, the light reflected by the partial transmission mirror 15 travels in the direction of the observer. With this configuration, the observer can observe the virtual image 16 of the intermediate image 13 formed by the relay optical system 12. The display by the virtual image 16 is presented at a position where the reflected light from the partial transmission mirror 15 is extended beyond the partial transmission mirror 15. Moreover, the light which permeate | transmitted the partial transmission mirror 15 among the light which injects into the partial transmission mirror 15 from the opposite side to an observer side advances to an observer's direction. With this configuration, the observer can observe the space beyond the partial transmission mirror 15 and the virtual image 16 at the same time.

  The condensing lens which comprises the relay optical system 12 is arrange | positioned so that a movement is possible back and forth about the direction which advances light. The position of the intermediate image 13 is changed by changing the position of the condensing lens that is an optical element constituting the relay optical system 12. The virtual image 16 can be displayed by changing the distance from the front focal point of the imaging optical system 14 to the intermediate image 13 by moving the position of the intermediate image 13 back and forth in the light traveling direction. By changing the distance from the front focal point to the intermediate image 13, the position of the virtual image 16 in the depth direction as viewed from the observer can be changed. The relay optical system 12 is an imaging position variable unit provided on the incident side of the imaging optical system 14 and changes the position of the virtual image 16 formed by the imaging optical system 14. Further, the size of the virtual image 16 can be appropriately set according to the size of the intermediate image 13.

  FIG. 2 explains 3D stereoscopic display by the display device 10. In the three-dimensional stereoscopic display, a plurality of planar images 17 sampled with respect to an object to be stereoscopically displayed are used. Each planar image 17 includes a cross-sectional image 18 of the object. Each cross-sectional image 18 is a cross-sectional image obtained when the object is cut into circles at predetermined intervals in the depth direction. The display panel 11 sequentially switches the plurality of planar images 17 by modulating light.

  The display device 10 sequentially changes the position of the intermediate image 13 by moving the optical elements constituting the relay optical system 12 in synchronization with the switching of the planar image 17 by the display panel 11. By sequentially changing the position of the intermediate image 13, the position of each planar image 17 that is the virtual image 16 is changed. By superimposing the cross-sectional images 18 sampled in advance on the object to be stereoscopically displayed in the depth direction, three-dimensional stereoscopic display becomes possible.

  Even if each of the cross-sectional images 18 of the objects included in each planar image 17 is viewed by itself, it is difficult to obtain a stereoscopic effect. By displaying each cross-sectional image 18 while changing the position by the display device 10, it becomes possible to stereoscopically display the internal configuration of the object. The closer the plane images 17 can be arranged in parallel, the higher the stereoscopic effect and presence. The switching of the planar image 17 by the display panel 11 needs to be performed within a time that allows stereoscopic viewing by the afterimage of each planar image 17. For example, by superimposing the planar images 17 displayed within 1/60 second, it is possible to obtain a high three-dimensional effect and a sense of reality.

  By adopting a configuration in which the reproduction position of the virtual image 16 is changed by the relay optical system 12 provided on the incident side of the imaging optical system 14, a large angle of view is adopted in the imaging optical system 14 and the relay optical system 12. Can be made small. In addition, since a plurality of display panels are not necessary, the display device 10 can have a simple configuration. Thereby, there exists an effect that a high-quality three-dimensional display can be performed with a simple configuration.

  Since the display device 10 of the present invention can display the inside of an object in a state close to a real object, it is useful, for example, when the structure of an object is shown in each field such as medical care and education. The display device 10 may superimpose surface images of objects. For example, it is possible to effectively produce a sense of depth of the object by superimposing the planar image 17 including the surface image having different luminance for each imaging position. As a result, the same display as in the conventional DFD (Depth Fused 3D) method using a plurality of panels can be realized by one display panel 11.

  The relay optical system 12 is not limited to changing the position of the intermediate image 13 in the light traveling direction. The relay optical system 12 may change the position of the intermediate image 13 in a two-dimensional direction substantially orthogonal to the light traveling direction. In this case, the position of the virtual image 16 can be changed in the two-dimensional direction. The relay optical system 12 may be configured to use a variable focus lens in addition to a configuration in which an optical element constituting the relay optical system 12 is moved. The relay optical system 12 can change the position of the virtual image 16 even if the focal length is changed by a variable focus lens. The display device 10 can use a variable focus lens that is small and can be easily formed even when a large angle of view is employed.

  The display device 10 may be configured such that the partial transmission mirror 15 is omitted and the light from the imaging optical system 14 is directly viewed. Furthermore, the display device 10 is not limited to the configuration in which the intermediate image 13 is formed by the relay optical system 12, and the relay optical system 12 may be omitted. When the relay optical system 12 is omitted, for example, the position of the virtual image 16 can be changed by changing the position of the display panel 11. When the position of the display panel 11 is changed, the display panel 11 functions as an imaging position variable unit. The display device 10 is not limited to the case where a transmissive liquid crystal panel is used as the display panel 11. As the display panel 11, a reflective liquid crystal display panel (Liquid Crystal On Silicon; LCOS), DMD (Digital Micromirror Device), or the like may be used. In the case of using an optical scanning type device, the same effect as changing the position of the optical element of the relay optical system 12 can be obtained by arranging a diffuser plate at the position of the intermediate image 13 and moving it. The image forming unit is not limited to one that forms an image by modulating light, and may be any unit that can sequentially switch the formed image.

  FIG. 3 shows a schematic configuration of the display device 20 according to the second embodiment of the present invention. The display device 20 of the present embodiment includes a phase modulation unit 22 that is an imaging position variable unit. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The light source unit 21 is a semiconductor laser that supplies laser light that is coherent light. The light source unit 21 may be configured to use a wavelength conversion element that converts the wavelength of laser light from the semiconductor laser, for example, a second harmonic generation (SHG) element. The light source unit 21 may use a semiconductor laser pumped solid state (DPSS) laser, a solid laser, a liquid laser, a gas laser, or the like instead of the semiconductor laser.

  The laser light from the light source unit 21 enters the phase modulation unit 22 in a parallel state. The phase modulation unit 22 is a transmissive display panel including a plurality of liquid crystal elements (not shown) corresponding to pixels. The phase modulation unit 22 is an image forming unit that forms an image by modulating the phase of the laser light from the light source unit 21, and is an imaging position variable unit provided on the incident side of the imaging optical system 14. is there. The phase modulation unit 22 generates diffracted light according to the phase modulation pattern. Since laser light, which is coherent light, is incident on the phase modulation unit 22, good diffraction characteristics can be obtained in the phase modulation unit 22.

  FIG. 4 shows a cross-sectional configuration of the liquid crystal element 30 provided in the phase modulation section 22 shown in FIG. The liquid crystal element 30 is configured by sealing a liquid crystal layer 42 with a first transparent substrate 31 and a second transparent substrate 34. A first transparent electrode 32 is formed between the first transparent substrate 31 and the liquid crystal layer 42. The 1st transparent electrode 32 can be comprised, for example with ITO and IZO which are metal oxides. A light shielding layer 33 is provided in a partial region between the first transparent electrode 32 and the liquid crystal layer 42. In addition, an alignment film (not shown) subjected to a rubbing process is formed.

  In a partial region on the second transparent substrate 34, a semiconductor layer 35, a gate insulating film 36 formed on the semiconductor layer 35, and a gate electrode 37 formed on the gate insulating film 36 are provided. Such a portion constitutes a thin film transistor (TFT) having a part of the semiconductor layer 35 as a source and a drain. An insulating film 38 made of silicon oxide or the like is formed on the second transparent substrate 34 and the TFT. A signal line 39 is provided on the TFT via an insulating film 38. The signal line 39 is connected to the source of the TFT. A scanning line (not shown) is connected to a gate electrode 37 which is a gate of the TFT.

  A PSG (Phosphosilicate glass) film 40 is formed on the insulating film 38, the signal line 39, and the scanning line. A second transparent electrode 41 is provided on a portion of the PSG film 40 other than the portion corresponding to the TFT. Similar to the first transparent electrode 32, the second transparent electrode 41 can be made of ITO or IZO. The TFT and the second transparent electrode 41 are formed for each pixel. In addition, an alignment film is also formed on the second transparent substrate 34 side. The rubbing direction of the alignment film on the second transparent substrate 34 side is parallel and opposite to the rubbing direction of the alignment film on the first transparent substrate 31 side. Thereby, the liquid crystal element 30 can obtain a uniform alignment state as a whole.

  The liquid crystal element 30 causes the second transparent substrate 34 to emit light that sequentially passes through the first transparent substrate 31, the first transparent electrode 32, the liquid crystal layer 42, and the second transparent electrode 41. The liquid crystal element 30 is disposed so that the polarization direction of the laser light incident on the first transparent substrate 31 matches the alignment direction of the liquid crystal molecules on the first transparent substrate 31 side. Thereby, the laser beam from the light source part 21 (refer FIG. 3) can be efficiently entered into the liquid crystal element 30.

  The phase modulation unit 22 is driven by, for example, an active matrix method. As the liquid crystal element 30, an electric field controlled birefringence mode liquid crystal can be used. By using a liquid crystal having a low molecular weight and a relatively high birefringence, the phase modulation unit 22 can respond at high speed, and sufficient phase modulation can be performed with a low driving voltage.

  Returning to FIG. 3, the phase modulation unit 22 forms the intermediate image 13 by changing the phase of light while generating diffracted light according to the phase modulation pattern. The imaging optical system 14 reproduces the virtual image 16 of the intermediate image 13 formed by the phase modulation unit 22. The phase modulation unit 22 changes the position of the intermediate image 13 by changing the phase of light. The phase modulation unit 22 sequentially switches the plurality of virtual images 16 by modulating the phase, and changes the positions of the plurality of virtual images 16. For example, the phase modulation unit 22 can change the position of the intermediate image 13 by presetting a phase modulation pattern for forming the intermediate image 13 at different positions in a device that drives the phase modulation unit 22. In the case of the present embodiment as well, high-quality stereoscopic display is possible with a simple configuration.

  FIG. 5 shows a schematic configuration of a display device 50 according to the first modification of the present embodiment. The display device 50 according to this modification is characterized in that the intermediate image 13 is formed using the first-order diffracted light from the phase modulation unit 22. The phase modulation unit 22 separates the zero-order diffracted light and the first-order diffracted light by causing the zero-order diffracted light to travel straight as indicated by the broken line arrow and the first-order diffracted light to travel obliquely as indicated by the solid line arrow. The phase modulation unit 22 forms the intermediate image 13 by using the first-order diffracted light traveling obliquely.

  The imaging optical system 14 is provided at a position where the first-order diffracted light from the phase modulation unit 22 is incident and other than the position where the zero-order diffracted light from the phase modulation unit 22 is incident. The phase modulation unit 22 can be configured to cause only the first-order diffracted light to enter the imaging optical system 14 by obtaining a large diffraction angle for the first-order diffracted light. The phase modulation unit 22 can obtain a large diffraction angle for the first-order diffracted light by arranging the liquid crystal elements 30 (see FIG. 4) at a narrow pitch. By forming the intermediate image 13 using the first-order diffracted light, when the amount of zero-order diffracted light is larger than that of the first-order diffracted light, the zero-order diffracted light and the first-order diffracted light overlap so that only a part of the virtual image 16 is present. It becomes possible to prevent brightening. This makes it possible to obtain a virtual image 16 having a good light quantity distribution.

  A display device 60 illustrated in FIG. 6 includes a prism 61 provided between the phase modulation unit 22 and the imaging optical system 14. The prism 61 is a triangular prism formed of a transparent member. The prism 61 advances the zero-order diffracted light from the phase modulation unit 22 in an oblique direction and causes the first-order diffracted light from the phase modulation unit 22 to travel straight by refraction. The prism 61 is a light separation unit that separates the zero-order diffracted light and the first-order diffracted light from the phase modulation unit 22.

  The display device 60 can be configured to linearly travel the first-order diffracted light by using the prism 61. Further, only the first-order diffracted light can be easily advanced in the direction of the imaging optical system 14. The prism 61 may be a prism other than a triangular prism. The light separation unit only needs to be able to separate the zero-order diffracted light and the first-order diffracted light, and an optical element other than the prism 61 may be used. In addition to the configuration in which the first-order diffracted light travels straight, the light separation unit may have a configuration in which the first-order diffracted light travels obliquely. The light separation unit is particularly useful when it is difficult to obtain a large diffraction angle in the phase modulation unit 22.

  FIG. 7 shows a schematic configuration of a display device 70 according to the second modification of the present embodiment. The display device 70 according to this modification includes a phase modulation unit 71 that is a reflective display panel. The phase modulation unit 71 reflects the laser light from the light source unit 21 to generate diffracted light corresponding to the phase modulation pattern. In the case of the display device 70 using the phase modulation unit 71 that generates diffracted light by reflecting laser light, the virtual image 16 can be displayed by changing the imaging position.

  FIG. 8 shows a schematic configuration of a display device 80 according to Embodiment 3 of the present invention. The display device 80 of this embodiment includes a display unit 81. The display unit 81 forms an image by modulating light. As the display unit 81, similarly to the display panel 11, a transmissive liquid crystal panel can be used. The display unit 81 is provided on the side opposite to the side on which the imaging optical system 14 is provided with respect to the partial transmission mirror 15 and in the vicinity of the position of the virtual image 16 formed by the imaging optical system 14.

  Of the light from the display unit 81, the light transmitted through the partial transmission mirror 15 travels in the direction of the observer. With this configuration, the display device 80 can display the virtual image 16 and the image of the display unit 81 in a superimposed manner. The display device 80 can perform display by fixing the image formed by the display unit 81 at the position of the display unit 81 and changing the position of the virtual image 16. For example, by moving the focal position of only the foreground that is the virtual image 16 without changing the focal position of the background displayed by the display unit 81, it is possible to produce a high sense of presence in image display. In addition, stereoscopic display may be performed by superimposing the image formed on the display unit 81 and the virtual image 16.

  The display unit 81 may be configured to use the light source unit 21 and the phase modulation unit 22 (see FIG. 3) described in the second embodiment, in addition to using a transmissive liquid crystal panel. The display unit 81 may use LCOS, DMD, or the like. Moreover, the display part 81 should just be what can display an image, and is not restricted to what forms an image at any time. The display unit 81 may display a fixed specific image. Furthermore, instead of the display unit 81, a display device described in each embodiment may be used. By using a plurality of display devices, it is possible to perform stereoscopic display by superimposing virtual images 16 of the display devices.

  As described above, the display device according to the present invention is useful as a display device that displays a stereoscopic display using a virtual image.

1 is a diagram showing a schematic configuration of a display device according to Embodiment 1 of the present invention. 3A and 3B are diagrams for describing three-dimensional stereoscopic display by a display device. The figure which shows schematic structure of the display apparatus which concerns on Example 2 of this invention. The figure which shows the cross-sectional structure of the liquid crystal element provided in the phase modulation part shown in FIG. FIG. 10 is a diagram illustrating a schematic configuration of a display device according to a first modification of the second embodiment. The figure which shows schematic structure of the display apparatus which has a prism. FIG. 10 is a diagram illustrating a schematic configuration of a display device according to a second modification of the second embodiment. FIG. 6 is a diagram illustrating a schematic configuration of a display device according to a third embodiment of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Display apparatus, 11 Display panel, 12 Relay optical system, 13 Intermediate image, 14 Imaging optical system, 15 Partial transmission mirror, 16 Virtual image, 17 Plane image, 18 Cross-sectional image, 20 Display apparatus, 21 Light source part, 22 Phase modulation Part 30 liquid crystal element 31 first transparent substrate 32 first transparent electrode 33 light shielding layer 34 second transparent substrate 35 semiconductor layer 36 gate insulating film 37 gate electrode 38 insulating film 39 signal line 40 PSG film, 41 second transparent electrode, 42 liquid crystal layer, 50 display device, 60 display device, 61 prism, 70 display device, 71 phase modulation unit, 80 display device, 81 display unit

Claims (7)

An image forming unit for forming an image;
An imaging optical system for reproducing an image formed by the image forming unit as a virtual image;
An imaging position variable unit that is provided on the incident side of the imaging optical system and changes a position of an image reproduced as a virtual image by the imaging optical system;
The imaging position variable unit includes a phase modulation unit which is the image forming unit that forms an image by modulating the phase of coherent light, and the phase modulation unit generates diffracted light according to a phase modulation pattern. While changing the phase of the light, an intermediate image is formed between the phase modulation unit and the imaging optical system, and the positions of the intermediate images sequentially switched by the image forming unit are changed. A display device that performs stereoscopic display by changing positions to be reproduced as a plurality of virtual images corresponding to the plurality of intermediate images by the imaging optical system.
The said phase modulation part changes the position of the said intermediate image by presetting the phase modulation pattern which forms the said intermediate image in a different position to the device which drives the said phase modulation part. The display device according to 1.
The display device according to claim 1, wherein the phase modulation unit is a transmissive or reflective display panel including a plurality of liquid crystal elements corresponding to pixels.
The zero-order diffracted light from the phase modulation unit is caused to travel straight, and the first-order diffracted light travels obliquely to separate the zero-order diffracted light and the first-order diffracted light, and the intermediate image is formed using the first-order diffracted light. The display device according to claim 1, wherein the display device is a display device.
A prism provided between the phase modulation unit and the imaging optical system, and by the refractive action of the prism, zero-order diffracted light from the phase modulation unit is caused to travel in an oblique direction; The display device according to claim 1, wherein the intermediate image is formed by linearly moving a first-order diffracted light and using the first-order diffracted light.
  The display device according to claim 1, further comprising a partial transmission mirror that transmits a part of the light from the imaging optical system and reflects another part of the light.   The display device according to claim 6, further comprising a display unit that is provided on a side different from the side on which the imaging optical system is provided with respect to the partial transmission mirror and displays an image.

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