JP2002372683A - Optical device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-performance optical device and a display device by a simple means. SOLUTION: When the wave front of the coherent light 110 emitted from a laser light source 101 is controlled by a Fraunhofer diffraction image recorded in a liquid crystal spatial optical modulator 103 and subjected to the Fourier transmission by the cornea 105 and the lens 106 of an observer, the reproduced image is obtained on the retina 107. Therefore, because the spatial optical modulator is only required to be in a size of a pupil, the whole device is made small in size and lightweight. By using the Fraunhofer diffraction image, three- dimensional images can be extremely easily reproduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device and a display device using the same.

[0002]

2. Description of the Related Art In a conventional optical device, as shown in FIG. 6, light 606 from a light source 601 is applied to a display element 603 by an optical system 602.
And the observer 605 observes the reproduced real image.

[0003] Further, as shown in FIG.
Guide the real image reproduced on the display element 603 to the left and right eyes,
A stereoscopic effect was obtained only by binocular parallax.

[0004]

However, the conventional optical device has a problem that the distance from the display device to the observer is long and the display body must be enlarged in order to reproduce a real image. For this reason, there is a problem that the entire optical device must be enlarged.

In addition, the conventional display device has a problem that the stereoscopic effect is unnatural because stereoscopic reproduction is performed without adjusting the thickness of the crystalline lens, and eyes are significantly fatigued when used for a long time.

The present invention has been made to solve the above problems, and has as its object to provide a high-performance optical device and display device by simple means.

[0007]

According to a first optical device of the present invention, a diffraction image is generated in the vicinity of a front focal position of an optical system for forming an image on a retina of an eyeball or on a side closer to the retina than the front focal position. Means is provided.

A second optical device according to the present invention is characterized in that, in the first optical device, a coherent light source and a spatial light modulator are used as means for generating the diffraction image.

A third optical device according to the present invention includes the first, second and third optical devices.
In the above optical device, an afocal optical system is used as a means for generating the diffraction image. According to a fourth optical device of the present invention, in the first to third optical devices, the diffraction image is a Fraunhofer diffraction image.

In a fifth optical device according to the present invention, in the second to fourth optical devices, the spatial light modulator is a phase modulation type.

A sixth optical device according to the present invention is characterized in that, in the second to fourth optical devices, the spatial light modulator is an amplitude phase modulation type.

According to a seventh optical device of the present invention, in the second to sixth optical devices, the spatial light modulator is a liquid crystal spatial light modulator.

The first display device of the present invention is the first display device of the present invention.
The optical device according to any one of (1) to (7) is used.

According to a second display device of the present invention, in the first display device, a means for detecting the direction of the eyeball and a shift of the optical system for forming an image on the retina of the eyeball from the Fourier transform lens are corrected. And means for performing the operation.

[0015]

The present invention will be described below in detail with reference to examples. (Embodiment 1) FIG. 1 shows the configuration of an optical apparatus according to the present invention. The coherent light 110 emitted from the laser light source 101 becomes parallel light by the collimating lens 102. The parallel light is transmitted to the liquid crystal spatial light modulator 10 by a signal from the driving device 104.
3, the wavefront is controlled, and the cornea 105 and the lens 10 of the observer are controlled.
By performing the optical conversion in step 6, a reproduced image is obtained on the retina 107.

The liquid crystal spatial light modulator used in this embodiment will be described. This liquid crystal spatial light modulator is an amplitude phase modulation type. FIG. 2 shows the configuration. An ECB (electric field control birefringence) panel 203 for phase modulation and a TN (twisted nematic) panel 206 for amplitude modulation were connected in an afocal system with microlens arrays 204 and 205 having the same focal length. F in the figure is the focal length of the microlens array. The conjugate image of each pixel of the ECB panel is arranged so as to form an image on the pixel of the TN panel. The polarizing plate 202 on the incident side is aligned with the direction of the director of the ECB panel. The direction of the director on the incident side of the TN panel is matched with the direction of the director of the ECB panel.
The direction of the polarizing plate 207 was adjusted to the direction in which the contrast ratio of the TN panel was maximized. Thereby, the amplitude and phase of light can be modulated independently. Both the TN panel and the ECB panel are of the active matrix drive type, and the pixel pitch is 10
μm × 10 μm.

The data of the Fraunhofer diffraction image is recorded on this liquid crystal spatial light modulator by the signal of the driving device. This driving device includes a driving circuit for a liquid crystal spatial light modulator, a memory for recording data of a Fraunhofer diffraction image, and a control circuit. An optically converted image (Fraunhofer diffraction image) of the image to be reproduced by the eyeball is calculated in advance, and the amplitude and phase data are recorded in the memory of the driving device. This data is read out one after another, a control circuit creates a control signal for the liquid crystal spatial light modulator, and a real-time changing Fraunhofer diffraction image is generated in the liquid crystal spatial light modulator through the drive circuit.

When this Fraunhofer diffraction image is irradiated with coherent light, the amplitude and phase are modulated, and a reproduced image is obtained on the retina. This reconstructed image can be changed in real time. Further, since the light wavefront from the three-dimensional object can be completely reproduced, a three-dimensional image can be easily reproduced.

Unlike the method of recording interference fringes, since the light wavefront is completely controlled, neither zero-order light nor -1st-order light is generated. For this reason, there is no possibility that the zero-order light or the like is burned into the retina.

The focal distance before synthesis by the cornea and lens of the eyeball is about 17 mm. Therefore, in front of the principal point of the eyeball 17
If a liquid crystal spatial light modulator is arranged in the vicinity of mm, an optically converted image close to a Fourier transformed image can be obtained on the retina. In the present embodiment, a Fourier transform that is easy to calculate is used in the data creation of the Fraunhofer diffraction image, and thus a deviation from the Fourier transform is corrected by the correction optical system 109. The correction optical system also performs correction for myopia, astigmatism, and the like as necessary.

The finer the pixel pitch of the spatial light modulator, the larger the reproduced image can be obtained. In this embodiment, 10 μm
m × 10 μm, and a reconstructed image of about 1.3 mm was obtained on the retina. The aperture (pupil) of the iris 108 is at most 8 mm in diameter
And the size of the liquid crystal spatial light modulator 103 is also 8 m.
It may be about m square. Accordingly, the collimating lens 102
Also has a diameter of about 1 cm, and the whole apparatus is very small and lightweight. (Embodiment 2) FIG. 3 shows another configuration of the optical device of the present invention. In this example, the diffraction image displayed on the liquid crystal spatial light modulator was reduced using an afocal system and then entered the eyeball.
In the figure, F indicates the focal length of the Fourier transform lens 301, and f indicates the focal length of 302.

A Fourier transform lens 301 is placed at a position F from the liquid crystal spatial light modulator. From there, the Fourier transform lens 302 is placed at the position (F + f). Then, a conjugate image 303 of the liquid crystal spatial light modulator is obtained at the position of f from the Fourier transform lens 302.

This conjugate image differs from the original image of the liquid crystal spatial light modulator only in the size of the top, bottom, left and right, but has exactly the same amplitude and phase distribution. This conjugate image is 17 mm in front of the principal point of the eyeball.
If placed near, a reconstructed image can be obtained on the retina.

The reduction ratio at this time is determined by the ratio of the focal lengths of the two lenses. In the present embodiment, it is one fifth. The liquid crystal spatial light modulator used in this embodiment has a pixel pitch of 40 μm,
The size is 5 cm square. Therefore, the size of the conjugate image is 1c
The m square and the pixel pitch are 8 μm.

In this embodiment, a liquid crystal spatial light modulator having a coarse pixel pitch can be used by changing the magnification of the afocal system. In addition, since the liquid crystal spatial light modulator does not need to be placed in front of the eyes, the application range of the device is expanded. (Embodiment 3) FIG. 4 shows a configuration of a display device of the present invention. The optical device of the present invention was placed in front of the left and right eyes. The present invention has realized a natural stereoscopic effect by binocular parallax and lens adjustment.

In this embodiment, a Fresnel conversion image is recorded on the liquid crystal spatial light modulator. This can be considered almost as a result of superimposing the lens function on the Fourier transform image.

The reproduced image of the Fourier transform is such that the appearance position is shifted between the right eye and the left eye in accordance with the depth. That is, a stereoscopic effect is first obtained by the binocular parallax.

Further, the focal length of the lens function to be superimposed on each object was changed depending on the position of the object in the depth direction.
As a result, an extremely natural three-dimensional effect with thickness adjustment of the crystalline lens was obtained.

In this embodiment, the displacement of the crystalline lens from the Fourier transform lens is corrected by data recorded in the liquid crystal spatial light modulator.

The correction data corresponding to the movement of the eyeball is stored in the memory 401 in advance.

Light emitted from the light emitting body 402 is reflected by the cornea and enters the optical position sensor 403. The movement of the eyeball is detected from the position of the return light, and the corresponding correction data is called from the memory 401. This correction data was superimposed on the original Fresnel transformed image and recorded in the liquid crystal spatial light modulator. As a result, a clear reproduced image was always obtained regardless of the direction of the line of sight. (Embodiment 4) FIG. 5 shows another configuration of the display device of the present invention. In this embodiment, the optical device of the second embodiment is used.
The liquid crystal spatial light modulator 503 and the lenses 301 and 302 constitute an afocal system. On the way, prisms 504, 505
Bent the light path. In the present embodiment, a kinoform was recorded using a phase modulation type liquid crystal spatial light modulator. The kinoform is obtained by applying a random phase to an original image and performing a Fourier transform to extract only a phase component (for details, see Appl. Opt. 12 (1973) 2328). However, in this embodiment, a lens function corresponding to the depth of the reproduced image is superimposed on the kinoform.

The light from the laser light source 501 is transmitted to the optical fiber 5
The light was guided at 02 and collimated by a collimating lens 102 for use.

In this embodiment, three colors (red, blue,
The laser of (green) was switched in time (every 15 ms) and used. By synchronizing this with data to be recorded in the liquid crystal spatial light modulator, a color three-dimensional moving image was reproduced.

In this embodiment, the response speed is increased by combining the TFT driving method and the nematic liquid crystal.
A ferroelectric liquid crystal may be used.

In this embodiment, a very natural three-dimensional effect was obtained.

Although the embodiment of the present invention has been described above, the present invention can be widely applied to a head-up display, a medical device, and the like.

[0037]

According to the optical apparatus of the present invention, the number of parts can be greatly reduced because the cornea and the crystalline lens of the observer are used as a part of the optical system. In addition, since the size of the spatial light modulator may be about the size of the pupil, the entire device becomes extremely small and lightweight. Moreover, since the spatial light modulator does not need to be enlarged, an effect that a high-definition spatial light modulator can be easily realized is produced. Further, since a Fraunhofer diffraction image is used, reproduction of a three-dimensional image is extremely easy.

Further, in the display device of the present invention, by changing the focal length of the lens function to be superimposed on the Fresnel transformed image of the object, an extremely natural three-dimensional effect with thickness adjustment of the crystalline lens can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration of an optical device according to the present invention.

FIG. 2 is a side view showing a configuration of a liquid crystal spatial light modulator used in an embodiment of the present invention.

FIG. 3 is a side view showing another configuration of the optical device of the present invention.

FIG. 4 is a top view illustrating a configuration of a display device of the present invention.

FIG. 5 is a side view showing another configuration of the display device of the present invention.

FIG. 6 is a side view showing a configuration of a conventional optical device.

FIG. 7 is a top view illustrating a configuration of a conventional display device.

[Explanation of symbols]

 Reference Signs List 101 laser light source 102 collimating lens 103 liquid crystal spatial light modulator 104 driving device 105 cornea 106 crystalline lens 107 retina 108 iris 109 correction optical system 110 coherent light 201 coherent light 202 polarizing plate 203 ECB panel 204 microlens array 205 microlens array 206 TN panel 207 Polarizer 208 Liquid crystal layer 209 Liquid crystal layer 301 Fourier transform lens 302 Fourier transform lens 303 Conjugate image 401 Memory 402 Light emitter 403 Optical position sensor 404 Driving device 501 Laser light source 502 Optical fiber 503 Liquid crystal spatial light modulator 504 Prism 505 Prism 601 Light source 602 optical system 603 display element 604 driving device 605 observer 606 light 701 lens

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] April 30, 2002 (2002.4.3
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

In order to achieve the above object, a first optical apparatus according to the present invention is provided in the vicinity of a front focal position of an optical system for forming an image on a retina of an eyeball or at a position closer to the front focus position. A means for generating a diffraction image on the side closer to the light source, and as a means for reproducing an optical wavefront from the diffraction image, a coherent light source and a phase modulation type spatial light modulator are provided.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

In order to achieve the above object, a second optical apparatus according to the present invention includes a diffractive image near an anterior focal position of an optical system for forming an image on a retina of an eyeball or on a side closer to the retina than that. And a means for generating a light wavefront from the diffraction image, comprising a coherent light source and an amplitude-phase modulation type spatial light modulator.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

In the first and second optical devices, it is preferable to use an afocal optical system as a means for reproducing the light wavefront from the diffraction image. Preferably, the diffraction image is a Fraunhofer diffraction image.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Deleted

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Deleted

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

Further, it is preferable that the spatial modulator is a liquid crystal spatial light modulator.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In order to achieve the above object, a display device of the present invention is characterized by using the above optical device.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014] Further, the apparatus is characterized in that it comprises means for detecting the direction of the eyeball, and means for correcting a shift of the optical system for forming an image on the retina of the eyeball from the Fourier transform lens.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/64 511 H04N 5/64 511A (72) Inventor Tomio Sonehara 3-5-5 Yamato, Suwa City, Nagano Prefecture No. Seiko Epson Corporation F-term (reference) 2H088 EA37 EA47 HA25 HA28 HA30 JA05 JA09 MA01 2H089 HA22 HA29 QA16 RA05 RA07 TA16 TA18 TA20 2H091 FA08X FA08Z FA29X FA29Z FA46Z FD02 HA07 HA09 LA16

Claims (9)

[Claims] 1. An optical apparatus, comprising: means for generating a diffraction image in the vicinity of a front focal position of an optical system for forming an image on a retina of an eyeball or on a side closer to the retina than the front focal position. 2. The optical device according to claim 1, wherein a coherent light source and a spatial light modulator are used as means for generating the diffraction image. 3. The optical device according to claim 1, wherein an afocal optical system is used as a means for generating the diffraction image. 4. The optical device according to claim 1, wherein the diffraction image is a Fraunhofer diffraction image. 5. The optical device according to claim 2, wherein said spatial light modulator is of a phase modulation type. 6. The optical device according to claim 2, wherein said spatial light modulator is of an amplitude phase modulation type. 7. The optical device according to claim 2, wherein the spatial light modulator is a liquid crystal spatial light modulator. 8. A display device using the optical device according to claim 1. 9. The apparatus according to claim 8, further comprising: means for detecting the direction of the eyeball, and means for correcting a deviation of the optical system for forming an image on the retina of the eyeball from the Fourier transform lens. Display device.