JP2003315728A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device capable of natural stereoscopic representation even when a modulation frequency of wavefront curvature is slower than a video rate. <P>SOLUTION: When a vertical synchronizing signal turns 'ON' in timing T0, laser light with wavefront curvature (a) is made incident on a vertical scanning system through a wavefront curvature modulating means and a horizontal scanning system until timing T2 to draw one image. The wavefront curvature modulating means is so driven from the T2 to T3 so that the modulated laser light has wavefront curvature (b). During this period, no laser light is emitted. Further, operation similar to that from the timing T0 to T3 is repeated from the timing T3 to T6, but an image with the wavefront curvature (b) is drawn in this case. Similarly, the operation from the timing T0 to T6 is repeated. Images with the wavefront curvature (a) and wavefront curvature (b) are alternately projected on the retina of an observer and put together through an after-image phenomenon, so that they are observed as an image in which perspective is represented. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device which scans a light beam and directly projects an image on the retina of an eye.

[0002]

2. Description of the Related Art In recent years, a so-called retinal scanning display in which a weak light beam emitted from a light source such as a laser or an LED is scanned by a two-dimensional optical scanning device and introduced into a pupil of an observer to directly draw on a retina. A so-called device is known (for example, refer to Patent Document 1). This retinal scanning type display is configured to be used by being worn on the head of an observer like eyeglasses, and can provide an image with high definition and a large angle of view. Such a retinal scanning type display is provided with a wavefront curvature modulating means for modulating the wavefront curvature of the generated light flux as a means for expressing the depth of an image incident on the observer's eye.

Here, the wavefront curvature will be described. The light emitted from the light source propagates as a wave of light traveling at a constant velocity and in phase in all directions centered on the light source, a so-called equipotential spherical wave. The spherical wave depends on the distance between the light source and the observer. Has different radius of curvature. If the light source is near, the image has a small radius of curvature, and if the light source is far, the image has a large radius of curvature. The observer can recognize the deviation of the radius of curvature through the focusing operation and feel a perspective. The wavefront curvature modulating means can enter the observer's eye as if the light source were present at an arbitrary distance, thus enabling natural stereoscopic vision.

[0004]

[Patent Document 1] Japanese Patent No. 2874208

[0005]

However, in the conventional image display device, the modulation frequency of the wavefront curvature by the wavefront curvature modulating means is compared with the frequency at which each pixel is modulated to form an image, that is, a so-called video rate. It was rather slow, and it was not possible to express the focus fluctuation in stereoscopic vision naturally. Therefore, an image display device capable of expressing natural stereoscopic vision has been desired.

The present invention has been made to solve the above problems, and realizes an image display device capable of expressing a natural stereoscopic view even when the modulation frequency of the wavefront curvature is slower than the video rate. With the goal.

[0007]

In order to achieve the above object, an image display device according to a first aspect of the present invention is an image display device, wherein at least one light source and a light beam emitted from the light source are intensity-modulated according to an image signal. Modulating means, an optical means for making the light beam modulated by the modulating means enter the pupil of the observer, and a light beam made incident by the optical means in a first direction and a direction substantially perpendicular to the first direction. In an image display device that forms a frame while scanning in a second direction and displays an image on the retina of the observer, a wavefront curvature modulating unit that modulates a wavefront curvature of the light flux is provided, and the wavefront curvature modulating unit includes: The wavefront curvature of the light flux is modulated during scanning in at least one of the first direction and the second direction.

In the image display device having this structure, the modulation means intensity-modulates the luminous flux emitted from at least one light source in response to the image signal, and the optical means impinges the modulated luminous flux on the observer's pupil. Since the wavefront curvature modulating means modulates the wavefront curvature of the incident light beam during scanning in at least one of the first direction and the second direction substantially perpendicular to the first direction, Form a frame while scanning the light flux in the first direction and the second direction,
An image can be displayed on the retina of the observer.

According to another aspect of the image display device of the present invention, at least one light source, modulation means for intensity-modulating the luminous flux emitted from the light source in accordance with an image signal, and the modulation means. An optical unit for making the light beam enter the pupil of the observer, and a frame formed by scanning the light beam made incident by the optical unit in the first direction and the second direction substantially perpendicular to the first direction. In the image display device for displaying an image on the retina of the observer by switching the frames with time, a wavefront curvature modulating means for modulating the wavefront curvature of the light flux is provided, and the wavefront curvature modulating means is at least the same. In the frame, the wavefront curvatures of the light beams are made substantially the same, and the wavefront curvatures of the light beams are modulated only when the frames are switched. Going on.

In the image display device having this structure, the modulation means intensity-modulates the luminous flux emitted from at least one light source according to the image signal, and the optical means impinges the modulated luminous flux on the pupil of the observer. , The wavefront curvature modulating means scans the incident light beam in the first direction and the second direction substantially perpendicular to the first direction, at least in the same frame of the frames formed, The wavefront curvature of the light flux is modulated only when the frame is switched so that the wavefront curvature of the light flux is substantially equalized. Therefore, by switching the frames formed by this light flux over time, an image is displayed on the retina of the observer. can do.

Further, in the image display apparatus according to a third aspect of the present invention, in addition to the configuration of the second aspect of the invention, the wavefront curvature modulating means modulates the wavefront curvature of the light beam each time the frame is switched. It is characterized by that.

In the image display device having this structure, in addition to the operation of the invention according to claim 2, the wavefront curvature modulating means can modulate the wavefront curvature of the light beam each time the frame is switched.

Further, in the image display device according to a fourth aspect of the present invention, in addition to the configuration of the invention according to any one of the first to third aspects, the wavefront curvature modulating means is provided in the first direction or the second direction. The wavefront curvature is modulated in synchronization with a synchronization signal that starts scanning in the direction.

In the image display device having this structure, in addition to the operation of the invention according to any one of claims 1 to 3, the wavefront curvature modulating means outputs a synchronizing signal for starting scanning in the first direction or the second direction. The wavefront curvature can be modulated in synchronization.

Further, in the image display apparatus according to a fifth aspect of the present invention, in addition to the structure of the fourth aspect of the invention, the wavefront curvature modulating means scans in the first direction and the second direction. Among them, the wavefront curvature of the light flux is made substantially the same during scanning in the direction of high scanning frequency, and the wavefront curvature is modulated in synchronization with a synchronization signal for starting scanning in the direction of low scanning frequency. ing.

In the image display device having this structure, in addition to the operation of the invention according to claim 4, the wavefront curvature modulating means performs the scanning in the direction having the higher scanning frequency among the scanning in the first direction and the second direction. In, the wavefront curvature of the light flux can be made substantially the same, and the wavefront curvature can be modulated in synchronization with a synchronization signal that starts scanning in the direction in which the scanning frequency is low.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an image display device according to the present invention will be described below with reference to the drawings. First, the configuration of the retinal scanning display 1 according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an overall configuration diagram showing the overall configuration of the retinal scanning display 1. FIG. 2 is a configuration diagram showing the configuration of the wavefront curvature modulating means 100.

As shown in FIG. 1, the retinal scanning display 1 is provided with a light source unit 2 for processing a video signal supplied from the outside. The light source unit 2 is provided with a video signal supply circuit 3 which receives a video signal from the outside and generates each signal serving as an element for synthesizing an image based on the video signal.
Output a video signal 4, a horizontal synchronizing signal 5, a vertical synchronizing signal 6, and a depth signal 7. In addition, the light source unit 2
R lasers 13 and G for emitting red (R), green (G), and blue (B) video signals respectively transmitted from the video signal supply circuit 3 as video signals 4 respectively. An R laser driver 10, a G laser driver 9, and a B laser driver 8 for driving the laser 12 and the B laser 11, respectively are provided. Further, a first collimating optical system 14 provided so as to collimate the laser light emitted from each laser into parallel light, and a dichroic mirror 15 for combining the collimated laser light,
A coupling optical system 16 for guiding the combined laser light to the optical fiber 17 is provided. A semiconductor laser such as a laser diode or a solid-state laser may be used as the R laser 13, the G laser 12, and the B laser 11. Further, the R laser 13, the G laser 12, and the B laser 11 are the light source in the present invention, and the light source unit section 2 is the modulating means in the present invention.

The retina scanning display 1 further includes a second collimating optical system 18 for collimating the laser light propagated from the light source unit 2 into parallel light again, and a wavefront curvature for modulating the collimated laser light. Modulation means 1
00, a horizontal scanning system 19 that horizontally scans the modulated laser light using the polygon mirror 19a, and laser light that is scanned by the horizontal scanning system 19 and is incident through the first relay optical system 20. A vertical scanning system 21 that scans in the vertical direction using the galvano mirror 21a is provided, and a second relay optical system 22 is provided so that the laser light scanned by the vertical scanning system 21 enters the pupil 24 of the observer. Has been.
The first relay optical system 20 includes a laser beam formed on the polygon mirror 19a of the horizontal scanning system 19 and a vertical scanning system 21.
The second relay optical system 22 makes the laser light imaged on the galvanometer mirror 21a conjugate with the laser light imaged on the galvanometer mirror 21a and the position of the pupil 24 of the observer. They are provided so as to be conjugated with the laser light imaged in. The second relay optical system 22
Is the optical means in the present invention.

Further, the drive circuit 23 is provided to drive the wavefront curvature modulating means 100 based on the depth signal 7 output from the video signal supply circuit 3. The horizontal scanning system 19 and the vertical scanning system 21 are respectively connected to the video signal supply circuit 3, and scan the laser light in synchronization with the horizontal synchronizing signal 5 and the vertical synchronizing signal 6 output from the video signal supplying circuit 3, respectively. It is configured.

Further, as shown in FIG. 2, the wavefront curvature modulating means 100 includes a beam splitter 101 for separating the incident laser light into a transmitted light and a reflected light reflected in a direction perpendicular to the transmitted light, and a beam splitter. A convex lens 102 having a focal length f that converges the laser light reflected by 101, and reflects the laser light converged by the convex lens 102 in the incident direction.
The movable mirror 103 is movable. The beam splitter 101 has a cube-like shape in which two right-angled prisms each having a dielectric multi-layered film on its slope are stuck together, and about 50% of the amount of incident light is reflected in the right-angle direction on the slope 101a. However, about 50% is transmitted.

The movable mirror 103 is composed of, for example, a mirror 104 having a reflecting surface 104a in which the surface of a transparent plate material such as glass is mirror-coated with a metal film, and a piezoelectric actuator 105 in which, for example, piezoelectric type piezo elements are laminated. The piezoelectric actuator 105 includes the drive circuit 23 (see FIG.
Driven by application of a drive voltage from the reference lens), the positional relationship between the mirror 104 fixed to the piezoelectric actuator 105 and the convex lens 102 is changed. The movable mirror 103 is movable in a direction perpendicular to the mirror surface of the mirror 104 (the X-axis direction in the figure), and the optical axes of the laser beams passing through the beam splitter 101 and the convex lens 102 are linearly aligned. There is.

Next, the process of the retinal scanning type display 1 according to the present invention from receiving an image signal from the outside to projecting an image on the retina of the observer will be described with reference to FIG. .

As shown in FIG. 1, in the retinal scanning display 1, when the video signal supply circuit 3 provided in the light source unit section 2 is supplied with a video signal from the outside, the video signal supply circuit 3 becomes red. , A video signal 4 composed of an R video signal, a G video signal, and a B video signal for outputting laser lights of respective colors of green, blue, a horizontal synchronizing signal 5, and a vertical synchronizing signal 6
And the depth signal 7 are output. R laser driver 1
0, G laser driver 9 and B laser driver 8 output respective drive signals to R laser 13, G laser 12, and B laser 11 based on the input R video signal, G video signal, and B video signal, respectively. To do. Based on this drive signal, the R laser 13, the G laser 12, and the B laser 11 each generate a laser beam, and each emits a laser beam.
Output to 4. The laser light generated from the point light source is collimated into parallel light by the first collimating optical system 14, and is further incident on the dichroic mirror 15 to be combined into one light beam, and then combined with the coupling optical system 16. Is guided to be incident on the optical fiber 17.

The laser light propagated by the optical fiber 17 is collimated again by the second collimating optical system 18 when it is emitted from the optical fiber 17, and is incident on the wavefront curvature modulating means 100. The wavefront curvature modulating means 100 that realizes the modulation of the wavefront curvature will be described later.

The laser light emitted from the wavefront curvature modulating means 100 is incident on the deflection surface 19b of the polygon mirror 19a of the horizontal scanning system 19. The polygon mirror 19a is a BD (Beam Detecto) output by an optical sensor (not shown).
The rotation speed is calculated based on the r) signal, and the uniform rotation speed is adjusted based on the BD signal so as to synchronize with the horizontal synchronization signal 5 output from the video signal supply circuit 3. The laser light incident on the deflecting surface 19b of the polygon mirror 19a is horizontally scanned and emitted through the first relay optical system 20 to the deflecting surface 21b of the galvano mirror 21a of the vertical scanning system 21. In the first relay optical system 20, the image formed on the deflection surface 19b of the polygon mirror 19a and the image formed on the deflection surface 21b of the galvano mirror 21a are adjusted so as to have a conjugate relationship, and the polygon Mirror 19
The trouble of a is corrected. Galvano mirror 21a
Like the polygon mirror 19a, in synchronization with the vertical synchronizing signal 6, the deflecting surface 21b reciprocally vibrates so as to reflect the incident light in the vertical direction.
The laser light is scanned in the vertical direction by a. The laser beam two-dimensionally scanned in the horizontal direction and the vertical direction by the horizontal scanning system 19 and the vertical scanning system 21 is a galvano mirror 2
1a and the image formed on the deflection surface 21b of the observer and the pupil 2 of the observer.
The second relay optical system 22 provided so as to have a conjugate relationship with the image formed at the position of 4 makes it enter from the pupil 24 of the observer and is projected on the retina. The observer can recognize the image by the laser light that is two-dimensionally scanned and is incident on the eye.

Next, a method of modulating the wavefront curvature in the retinal scanning display 1 will be described with reference to FIGS. FIG. 3 is a schematic diagram showing a mode in which the laser light is modulated by the wavefront curvature modulating means 100.

As shown in FIG. 2, the wavefront curvature modulating means 10
The laser beam collimated into parallel light by the second collimating optical system 18 (see FIG. 1) enters the 0 beam splitter 101 from the + Y direction as incident light. About 50% of the incident laser light amount is the slope 101a.
And is incident on the convex lens 102 provided in the reflection direction (-X direction). By the way, when the drive voltage applied to the piezoelectric actuator 105 from the drive circuit 23 shown in FIG. 1 is 0 or a predetermined reference value (reference state), the reflecting surface 104 a of the mirror 104 of the movable mirror 103 is the main surface of the convex lens 102. It is adjusted in advance so that the distance to the point is the same as the focal length of the convex lens 102. In this reference state, the laser light incident on the convex lens 102 is refracted and converged by the convex lens 102, and is focused on the reflecting surface 104a. In this case, the laser light is reflected by the reflecting surface 104a in the same axial direction as the incident light (+ X direction), and the laser light that was a convergent light upon entering the mirror 104 becomes a diffused light after the reflection. The light enters the convex lens 102 again.

The diffused light reflected by the reflecting surface 104a in the + X direction and incident on the convex lens 102 has the same divergence angle as the convergent angle of the convergent light converged by the convex lens 102 before being reflected by the reflecting surface 104a. Since it passes through the same optical path in the same optical system as when it converges, this diffused light is refracted at the same angle as when it converged and collimated into parallel light when it passes through the convex lens 102. The laser light collimated into parallel light is re-incident on the beam splitter 101, and about 50% of the light quantity is incident on the slope 101a.
Through the second collimating optical system 18 and in a direction (+ X direction) forming a right angle with the incident light from the second collimating optical system 18,
It is emitted as emitted light from 0.

Further, as shown in FIG. 3, the drive circuit 23
When a predetermined drive voltage from (see FIG. 1) is applied, the piezoelectric actuator 105 is driven, and the drive causes the movable mirror 103 to move a distance d in the + X direction from the position in the reference state. In this case, the distance between the reflecting surface 104a of the mirror 104 and the principal point of the convex lens 102 is changed to fd.
About 50% of the laser light, which is incident light that is incident as parallel light from the + Y direction from the second collimating optical system 18, is reflected by the inclined surface 101a of the beam splitter 101 in the −X direction, It is incident on the convex lens 102. The convex lens 102 emits the laser light incident from the + X direction in the −X direction so as to refract and converge the laser light, but the reflecting surface 104 a of the mirror 104 of the movable mirror 103.
Has been moved to a position closer to the convex lens 102 by a distance d than the focal length f of the convex lens 102, so that the laser light is not converged on the reflecting surface 104a. The laser light is reflected in the + X direction by the reflecting surface 104a, then is focused at a position advanced by a distance d, that is, a position of a distance f-2d, and is incident on the convex lens 102 again.

The convex lens 102 receives the incident laser beam,
The convex lens 1 refracts the light so that its spread converges.
Since the refractive index of 02 itself does not change, the convex lens 102 that collimates the light emitted from the position of the focal length f into the parallel light cannot collimate the light emitted from the position of the distance f-2d into the parallel light. . Therefore, the laser light focused at the distance f-2d is incident on the convex lens 102, but the spread angle thereof becomes smaller, but the parallel laser light is not collimated and passes through the convex lens 102 and spreads after passing through the convex lens 102. The beam enters the beam splitter 101 while maintaining the angle. Beam splitter 101
Approximately 50% of the laser light incident on the laser beam passes through the slope 101a and is emitted in the + X direction while maintaining the spread angle, that is, as diffused light. Therefore, the wavefront curvature modulating means 100 emits laser light having a predetermined spread angle as emitted light, that is, laser light having a large wavefront curvature unlike parallel light.

The wavefront curvature on the deflecting surface 19b of the laser light emitted from the wavefront curvature modulating means 100 as diffused light and entering the deflecting surface 19b of the polygon mirror 19a of the horizontal scanning system 19 shown in FIG. , Apparent emission point 12
The wavefront curvature is equivalent to that of the light emitted from No. 5. Further, the wavefront curvature of the parallel light emitted when the distance between the reflecting surface 104a and the principal point of the convex lens 102 is f, on the deflecting surface 19b of the polygon mirror 19a, is the same as that of the light emitted from infinity. It becomes a curvature. Here, the first relay optical system 20
The image formed on the deflecting surface 19b of the polygon mirror 19a and the image formed on the deflecting surface 21b of the galvano mirror 21a by the second relay optical system 22 are also deflected by the second relay optical system 22. Since each relay optical system is provided so that the image formed above and the image formed at the position of the observer's pupil 24 have a conjugate relationship, the deflecting surface 19b of the polygon mirror 19a. The image formed above and the image formed at the position of the pupil 24 of the observer have a conjugate relationship. Therefore, the polygon mirror 19
The wavefront curvature of the laser light on the deflection surface 19b of a becomes the same as the wavefront curvature at the position of the pupil 24 of the observer.

When the observer focuses the apparent emission point 125 of the laser light incident on the eye from the pupil 24, the laser light is imaged on the retina of the observer. by the way,
Since the observer can identify the difference in the wavefront curvature of the laser light by the focusing operation (so-called adjusting action), the observer can recognize the perspective based on the difference in the wavefront curvature of the laser light. That is, it is felt that the laser light having a large wavefront curvature is emitted from a near position, and the laser light having a small wavefront curvature is emitted from a distant position. Therefore, in this case, the observer has an apparent emission point 125.
Then, it is recognized that the emission point of the laser beam exists at a position corresponding to the distance to the deflection surface 19b that is conjugate to the position of the pupil 24.

Convex lens 102 of wavefront curvature modulating means 100
Assuming that the focal length of 4 is 4 mm, the wavefront curvature modulation means 100 can express a perspective of about 30 cm to infinity only by moving the movable mirror 103 by about 30 μm. In addition, the focal length of the convex lens 102 is 2
In the case of mm, the movable mirror 103 only moves about 10 μm, and the wavefront curvature modulating means 100 has about 30 c.
You can express a sense of perspective from m to infinity. For example, when a laser beam having a substantially parallel light flux with a small wavefront curvature is scanned and enters the eye, an observer can recognize it as an image presented on a screen several tens of meters away, and a laser with a large wavefront curvature. When the light is scanned and enters the eye, the observer is tens of c
It can be recognized as an image presented on the screen m ahead.

Next, the image is projected on the retina of the observer, which is changed according to the relationship between the period of modulation of the wavefront curvature by the wavefront curvature modulating means 100 and the period of generation of the horizontal synchronizing signal 5 and the vertical synchronizing signal 6. The perspective expressed in the displayed image will be described. First, the retinal scanning display 1 according to the first embodiment will be described with reference to FIGS. 1 and 4 to 7. In FIG. 4, the period of modulation of the wavefront curvature of the wavefront curvature modulating means 100 in the first embodiment is the vertical synchronization signal 6
2 is a timing chart in the case where the cycle is twice as long as the occurrence cycle of. FIG. 5 is a diagram showing frames formed when the frames whose wavefront curvatures are modulated by the wavefront curvature modulating means 100 are alternately formed. FIG. 6 shows the wavefront curvature a,
It is a figure which shows the image 32 which two frames of wavefront curvature b were synthesize | combined. FIG. 7 is a diagram showing an arrangement in the depth direction of each element that constitutes the image 32 in which two frames having the wavefront curvature a and the wavefront curvature b are combined.

The wavefront curvature a and the wavefront curvature b shown in FIGS. 4 and 5 are assumed to be such that the wavefront curvature a is smaller than the wavefront curvature b. In this case, the radius of curvature of the light beam having the wavefront curvature a is larger than the radius of curvature of the light beam having the wavefront curvature b. Therefore,
When the radius of curvature of the light flux having the wavefront curvature a is infinite, the frame 30 having the wavefront curvature a is drawn as an image recognized to exist at a far position in front of the observer, that is, a long-distance image, and When the radius of curvature of the light flux is 1 m, the frame 31 having the wavefront curvature b is drawn as an image that is considered to exist 1 m in front of the observer, that is, an image at a short distance.

The image projected on the retina of the observer is, for example, a screen for one frame made up of a plurality of pixels of 640 dots in the vertical direction and 480 dots in the horizontal direction, that is, one frame is 60 sheets per second continuously. It is formed by drawing a pattern. A polygon mirror 19a of a horizontal scanning system 19 shown in FIG. 1 horizontally scans the modulated laser light incident from the wavefront curvature modulating means 100. Horizontal scanning system 1
Every time the horizontal synchronizing signal 5 is input to the display device 9, for example, in the case of the hexagonal polygon mirror 19a, one-sixth rotation is performed, and in the meantime, one vertical dot and 480 horizontal dots, that is, one line of pixels is displayed. Laser beam is scanned. next,
The laser beam scanned in the horizontal direction is scanned in the vertical direction by the vertical scanning system 21. Each time the vertical synchronizing signal 6 is input to the vertical scanning system 21, the galvano mirror 21a makes one reciprocating motion in the vertical direction, and during the deflection in one direction, the vertical 6
The scanning of 40 dots, that is, 640 lines by the horizontal scanning system 19 is performed. When one frame is drawn in 1/60 seconds, the observer may see 640 × 4 due to the afterimage phenomenon.
This frame can be recognized as one screen on which 80 dots, that is, about 300,000 pixels are simultaneously displayed. For example, an image of a video game or the like is 60 frames / second, an image of a television or a video is 30 frames / second (NTSC system), and an image projected by a projector has a drawing speed of 24 frames / second. Therefore, even at such a drawing speed, it can be said that a substantially sufficient effect as an image can be obtained. As described above, in the retinal scanning display 1, one frame is formed by the series of scanning with the laser light, and redrawing of the frame is repeated 60 times per second.

When the modulation cycle of the wavefront curvature of the wavefront curvature modulating means 100 is set to be twice the generation cycle of the vertical synchronization signal 6, one image is drawn for each cycle of the vertical synchronization signal 6. Since it is performed, the modulation of the wavefront curvature of the laser light is performed for one cycle every time two images of the retinal scanning display 1 are drawn.

As shown in FIG. 4, when the vertical synchronizing signal 6 turns "ON" at the timing T0, the galvano mirror 21a of the vertical scanning system 21 starts scanning the laser light in the vertical direction. At this time, the wavefront curvature modulating means 100
It is driven so that the wavefront curvature of the modulated laser light becomes a, and the vertical scanning system 2 via the wavefront curvature modulating means 100 and the horizontal scanning system 19 during the timings T0, T1 and T2.
The wavefront curvature of the laser light entering 1 is a. Then, one scan of the vertical scanning system 21 started at the T0 timing ends at the T2 timing, and the drawing of one frame ends. In this way, the frame having the wavefront curvature a, that is, the frame 30 (long-distance image) having the wavefront curvature a illustrated in FIG. 5 is formed. When an observer views this frame, the object 30a drawn on the frame is observed as being present at infinity of the observer, for example. Further, the vertical synchronization signal 6 becomes "OFF" at the timing T1.

Next, from the T2 timing to the T3 timing, the laser light modulated by the wavefront curvature modulating means 100 is
The wavefront curvature modulating means 100 is driven so that the wavefront curvature which was a until then becomes b. The formation of one frame is completed by the T2 timing, and no laser light is generated from the T2 timing to the T3 timing.

Further, at timings T3, T4, T5 and T6, the same operation as that at the timings T0, T1, T2 and T3 is repeated, but at this time, the wavefront curvature of the laser light incident between the timings T4 and T5. The wavefront curvature modulating means 100 is driven so as to modulate the wavefront into b. And
The laser beam scanned by the horizontal scanning system 19 and the vertical scanning system 21 completes the formation of the frame 31 (short-distance image) having the wavefront curvature b illustrated in FIG. 5 at the timing T5. When an observer views this image, the object 31a drawn in the frame is observed as being present 1 m in front of the observer, for example. Further, the vertical synchronization signal 6 becomes "OFF" at the timing T4.

Thereafter, similarly, in the retina scanning display 1, the operation between the timings T0 to T6 is repeated. For example, when the vertical synchronization signal 6 is 60 times per second, "ON", "O"
When FF ”is repeated, retina scanning type display 1
Will repeat the operation at timings T0 to T6 30 times per second. An image projected on the retina of the observer such that a frame 30 having a wavefront curvature a drawn 30 sheets per second and a frame 31 having a wavefront curvature b drawn 30 sheets per second are alternately overlapped, Due to the afterimage phenomenon, the observer recognizes it as an image projected by superimposing the frame 30 and the frame 31. That is, the observer is
As shown in, the long distance object 30a and the short distance object 31
A combined image 32 in which a and a are displayed in one image
Observe as.

Further, as shown in FIG. 7, the combined image 32 is recognized by the observer as an image as viewed from the direction A of the arrow. The observer observes the objects 31a and 30a from the position of 0 in the depth direction, and the object 31a is on the plane orthogonal to the depth direction of the position 1 / b on the plane orthogonal to the depth direction of the position 1 / b. It feels like there is an object 30a. As described above, the reciprocal of the wavefront curvature is the radius of curvature.

Next, the retinal scanning display 1 according to the second embodiment will be described with reference to FIGS. 1 and 8 to 10. FIG. 8 is a timing chart when the wavefront curvature modulation period of the wavefront curvature modulation means 100 in the second embodiment is the same as the generation period of the vertical synchronization signal 6. FIG. 9 is a diagram showing a combined image 33 having different wavefront curvatures in the vertical direction. FIG. 10 is a diagram showing the arrangement in the depth direction of the respective elements that form the image 33 that is synthesized by having different wavefront curvatures in the vertical direction.

When the operating period of the wavefront curvature modulating means 100 is equal to or shorter than the operating period of the vertical scanning system 21, an image having a different wavefront curvature depending on the operation is formed according to the operation of the vertical scanning system 21. can do. When the operation cycle of the wavefront curvature modulating means 100 is equal to the operation cycle of the vertical scanning system 21, 1 is set for each cycle of the vertical synchronizing signal 6.
Since the frame is drawn, the modulation of the wavefront curvature of the laser light is performed for one cycle every time one frame of the retinal scanning display 1 is drawn.

As shown in FIG. 8, when the vertical synchronizing signal 6 is turned "ON" at the timing T0, the scanning of the laser beam in the vertical direction by the galvano mirror 21a of the vertical scanning system 21 is started. At this time, the wavefront curvature modulating means 100
It is driven so that the wavefront curvature of the modulated laser light becomes a, and it is driven so that the wavefront curvature is trigonometrically changed to b during the timings T0, T1, and T2. That is, the wavefront curvature of the laser light incident on the vertical scanning system 21 via the wavefront curvature modulating means 100 and the horizontal scanning system 19 changes from a to b in accordance with one scan by the vertical scanning system 21. Then, one scan of the vertical scanning system 21 started at the T0 timing ends at the T2 timing, and the drawing of one frame ends. Further, the vertical synchronization signal 6 becomes "OFF" at the timing T1.

Next, from the timing T2 to the timing T3, the wavefront curvature modulating means 100 is driven so that the wavefront curvature of the laser light becomes a in preparation for the next operation cycle of the wavefront curvature modulating means 100. The formation of one frame is completed by the T2 timing, and no laser light is generated from the T2 timing to the T3 timing.

Further, at timings T3, T4, T5 and T6, operations similar to those at the timings T0, T1, T2 and T3 are repeated.

Thereafter, similarly, in the retina scanning display 1, the operation between the timings T0 to T3 is repeated. For example, when the vertical synchronization signal 6 is 60 times per second, "ON", "O"
When FF ”is repeated, retina scanning type display 1
Would repeat the operation at timings T0 to T3 60 times per second. In one frame formed in this way, for example, when the scanning of the galvano mirror 21a is performed from the top to the bottom of the screen, the combined image 33 incident on the observer's eyes shown in FIG. From the lower side to the upper side, the lower side is displayed as a short distance and the upper side is displayed as a long distance. Therefore,
The observer observes that the object 31a displayed below the image is in the front and the object 30a displayed above the image is in the distance.

Further, as shown in FIG. 10, the combined image 33 is recognized by the observer as an image as viewed from the direction B of the arrow. The observer observes the objects 31a and 30a from the position of 0 in the depth direction, and the combined image 33
It is felt that the object 31a and the object 30a are present on the slope 33a whose depth fluctuates from 1 / b to 1 / a in a trigonometric manner from below to above.

Next, the retinal scanning display 1 according to the third embodiment will be described with reference to FIGS. 1 and 11 to 14. FIG. 11 is a timing chart showing the relationship between the modulation cycle of the wavefront curvature of the wavefront curvature modulating means 100 and the generation cycle of the vertical synchronizing signal 6 in the third embodiment. FIG. 12 is a timing chart showing the relationship between the change in the wavefront curvature near the T1a timing in FIG. 11 and the generation cycle of the horizontal synchronization signal 5. Figure 13
It is a figure which shows the image 34 which has a different wavefront curvature in the up-down direction and the left-right direction, and was synthesize | combined. FIG. 14 shows an image 34 synthesized with different wavefront curvatures in the vertical and horizontal directions.
It is a figure which shows arrangement | positioning in the depth direction of each element which comprises.

When the operating period of the wavefront curvature modulating means 100 is equal to or shorter than the operating period of the horizontal scanning system 19, it varies depending on the part in accordance with the respective operations of the horizontal scanning system 19 and the vertical scanning system 21. Images with wavefront curvature can be formed. When the modulation cycle of the wavefront curvature of the wavefront curvature modulating means 100 is set to be the same as the generation cycle of the horizontal synchronizing signal 5, the modulation of the wavefront curvature of the laser light is performed by drawing one line in the horizontal direction. Each time it is performed, one period of modulation is performed. Then, in each generation cycle of the vertical synchronizing signal 6, the horizontal scanning system 19 scans by the number of horizontal scanning lines of one image, and one image is drawn.

The timing chart shown in FIG.
As shown in FIG. 13, a long-distance object 30a is displayed above, and a short-distance object 31a is displayed below, and the short-distance object 31a is displayed.
In order to express that the central part of a is located closer than the left and right ends, the waveform is such that it is superimposed on the vertical modulation to perform horizontal modulation. In this timing chart, the wavefront curvature a corresponds to an infinite distance, and the wavefront curvature b corresponds to a value at the shortest distance point in a short distance image. Further, in the short-distance image, the wavefront curvature fluctuates in the left-right direction between b ′ and b.

As shown in FIG. 11, at T0 timing,
When the vertical synchronizing signal 6 is turned “ON”, the scanning of the laser beam in the vertical direction by the galvano mirror 21a of the vertical scanning system 21 is started. At this time, the wavefront curvature modulating means 100
Is driven so that the wavefront curvature of the modulated laser light is a, and is driven so that the wavefront curvature is trigonometrically changed to b during T0, T1, and T2 timings. That is, the wavefront curvature of the laser light incident on the vertical scanning system 21 via the wavefront curvature modulating means 100 and the horizontal scanning system 19 varies between a and b in accordance with one scan by the vertical scanning system 21. Then, one scan of the vertical scanning system 21 started at the T0 timing ends at the T2 timing, and the drawing of one frame ends. Further, the vertical synchronization signal 6 becomes "OFF" at the timing T1.

During this T0, T1, T2 timing, as shown in FIG. 12, the horizontal synchronizing signal 5 is also periodically generated, and "ON" and "OFF" are repeated. Then, the wavefront curvature modulating means 100 is driven so that the fluctuation for one cycle is performed in accordance with one scan of the horizontal scanning system 19. Horizontal sync signal 5 is "ON" at the timing of T0 '
Then, the scanning of the laser light in the horizontal direction by the polygon mirror 19a of the horizontal scanning system 19 is started. At this time, the wavefront curvature modulating means 100 is driven so that the wavefront curvature of the modulated laser light becomes b ′, and T0 ′, T0.
During the 1 ′ and T2 ′ timings, the wavefront curvature is trigonometrically changed to b, and the wavefront curvature is driven so as to be similarly changed to b ′. That is, the wavefront curvature of the laser light incident on the horizontal scanning system 19 from the wavefront curvature modulating means 100 changes from b ′ to b in accordance with one scan of the horizontal scanning system 19, and b ′ has a so-called sin curve-like shape. Make a periodic fluctuation. Then, one scan of the horizontal scanning system 19 started at the T0 ′ timing is finished at the T2 ′ timing, and the drawing of one line is finished. Further, the horizontal synchronization signal 5 turns “OFF” at the timing T1 ′.

Further, at T2 ', T3' and T4 'timings, the same operation as at T0', T1 'and T2' timings is repeated. After that, similarly, the periodical modulation of the wavefront curvature is performed in synchronization with the horizontal synchronizing signal 5. Note that the wavefront curvature b ′ takes a value that fluctuates arbitrarily within the range of the wavefront curvature a and the wavefront curvature b, and the wavefront curvature b ′ at both ends takes a value that is smaller than the wavefront curvature b, so it is drawn in one scan. It is displayed as one horizontal scanning line in which the sense of perspective changes trigonometrically, with both ends being a long distance and the center being a short distance from both ends to the center on one line. Of course, since the example of FIG. 12 is an example near the timing T1a of FIG. 11, when the maximum value of the wavefront curvature does not become b at other timings (for example, the long-distance image portion in the frame is drawn). If you have.)

Next, from the timing T2 to the timing T3 shown in FIG. 11, the wavefront curvature modulating means 100 is set so that the wavefront curvature of the laser light becomes a in preparation for the next operation cycle of the wavefront curvature modulating means 100. Is driven. The formation of one image is completed by the T2 timing, and the laser light is not generated from the T2 timing to the T3 timing.

Further, at timings T3, T4, T5 and T6, operations similar to those at the timings T0, T1, T2 and T3 are repeated.

In the example of the combined image 34, the far-field object 30a displayed above has almost no change in the wavefront curvature in the left-right direction, and therefore the wavefront curvature modulation synchronized with the horizontal scanning is performed above the image. Is not done or very few.

Thereafter, similarly, in the retina scanning display 1, the operation between the timings T0 to T3 is repeated. For example, when the vertical synchronization signal 6 is 60 times per second, "ON", "O"
When FF ”is repeated, retina scanning type display 1
Would repeat the operation at timings T0 to T3 60 times per second. In the image formed in this way, for example, when the scanning of the galvano mirror 21a is performed from the upper side to the lower side of the image, the combined image 34 incident on the observer's eye shown in FIG. From the upper part to the upper part, the lower part is displayed as a short distance and the upper part is displayed as a long distance. Further, in the lower part of the image, the central part is displayed closer than the left and right ends, and is displayed as an image expressing the perspective. Therefore, in the retinal scanning display 1, the observer observes that the object 31a displayed below the image is in the front, and the object 30a displayed above the image is in the distance. It is possible to express a feeling and a partial stereoscopic effect in which the central portions of the objects 30a and 31a are observed closer than the left and right end portions.

Further, as shown in FIG. 14, the combined image 34 is recognized by the observer as an image as viewed from the direction C of the arrow. The observer observes the objects 31a and 30a from the position of 0 in the depth direction, and the synthesized image 34
From the bottom to the top, the depth fluctuates trigonometrically from 1 / b to 1 / a, and the object 30a and the object 31a are formed on the slope 34a having a stereoscopic effect in the depth direction from the left and right end portions to the central portion. I feel like I exist.

As described above, in the retina scanning type display 1 of the present embodiment, the horizontal synchronizing signal 5 and the vertical synchronizing signal 6 which are the reference of the driving timing of the horizontal scanning system 19 and the vertical scanning system 21 are tuned. Wavefront curvature modulating means 10
0 is operated, and the wavefront curvature of the laser light is modulated. First
In the retinal scanning display 1 of the above embodiment, an image having a far / near binary wavefront curvature is formed, and the positional perspective of the objects 30a and 31a expressed in the image can be expressed. In addition, in the retinal scanning display 1 of the second embodiment, an image in which the sense of perspective is smoothly changed in the vertical direction of the image is formed, and the objects 30a and 31a represented in the image are arranged in the vertical direction. Different perspectives can be expressed depending on the position. Further, in the retinal scanning display 1 according to the third embodiment, an image with a smooth perspective change in the vertical direction of the image is formed, and a smooth stereoscopic change in the horizontal direction of the image occurs. The formed image is formed, and different perspective and stereoscopic effects can be expressed depending on the arrangement positions of the objects 30a and 31a expressed in the image.

Further, by making the change of the wavefront curvature by the horizontal scanning system and the vertical scanning system trigonometrical, the operation load of the piezoelectric actuator 105 of the wavefront curvature modulating means 100 can be reduced, so that one frame is drawn. Even when the wavefront curvature modulating means 100 cannot obtain a sufficient modulation speed with respect to the speed, that is, even when the driving frequency of the piezoelectric actuator 105 is small, it is possible to prevent the image from being disturbed in the vicinity of the scanning line, which causes a feeling of strangeness. It is possible to draw a natural stereoscopic image. Further, by synchronizing the switching timing of the driving cycle of the piezoelectric actuator 105 with the horizontal synchronizing signal 5 or the vertical synchronizing signal 6, the driving of the piezoelectric actuator 105 is synchronized with the timing of starting scanning of one line or drawing of one frame. Therefore, it is possible to prevent the stereoscopic image to be drawn from being displaced or flickering.

The retinal scanning display 1 of the present invention
The present invention is not limited to the first, second and third embodiments, and various modifications are possible. For example, in the present embodiment, a long distance is expressed in the upper direction of the image and a short distance is expressed in the lower direction. However, the perspective based on the vertical direction can be arbitrarily expressed, for example, when looking into a tunnel. You can Further, in the third embodiment, the central portion below the image is represented as an image in which the distance is shorter than both end portions, but the stereoscopic effect based on the left-right direction may be represented arbitrarily. Also, the stereoscopic effect may be expressed in the left-right direction even at the upper side.

Further, in this embodiment, the polygon mirror 19a is assumed to be, for example, a hexagon, and its deflecting surface 19b is formed.
However, the number is not limited to this, and may be any number, for example, 4, 12, or 48.

[0066]

As described above, in the image display device according to the first aspect of the present invention, the modulating means intensity-modulates the luminous flux emitted from at least one light source in accordance with the image signal, and the optical means comprises: The modulated light flux is incident on the pupil of the observer, and the wavefront curvature modulating means scans the incident light flux in at least one of the first direction and the second direction substantially perpendicular to the first direction. Since the wavefront curvature of the light flux is modulated therein, a frame can be formed while scanning this light flux in the first direction and the second direction, and an image can be displayed on the retina of the observer. Therefore, if the observer gazes at an arbitrary place on the frame, it is possible to focus on that place by the focus adjusting action of the observer's eye, and it is possible to realize a natural stereoscopic view centered on that place. it can.
Further, stereoscopic vision can be realized even with only one eye of the observer.

In the image display device according to the second aspect of the present invention, the modulating means intensity-modulates the luminous flux emitted from at least one light source according to the image signal, and the optical means observes the modulated luminous flux. At least the same frame formed by scanning the incident light flux in the first direction and the second direction substantially perpendicular to the first direction, the light flux being incident on the pupil of the person and being incident on the wavefront curvature modulating means. In this case, the wavefront curvature of the light flux is modulated to be substantially the same, and the wavefront curvature of the light flux is modulated only when the frames are switched. Therefore, by switching the frames formed by this light flux with time, Images can be displayed on the retina of. Therefore, if the observer pays attention to an arbitrary image among the images displayed on the frame to be switched, the image can be focused by the focus adjusting function of the observer's eyes, and the natural place centered on the place can be focused. It is possible to realize stereoscopic vision. Further, stereoscopic vision can be realized even with only one eye of the observer.

Further, in the image display device according to the third aspect of the invention, in addition to the effect of the second aspect of the invention, the wavefront curvature modulating means can modulate the wavefront curvature of the light beam each time the frame is switched. Therefore, it is possible to prevent the displacement and flicker of the stereoscopic image.

Further, in the image display device of the invention according to claim 4, in addition to the effect of the invention according to any one of claims 1 to 3, the wavefront curvature modulating means scans in the first direction or the second direction. The wavefront curvature can be modulated in synchronization with the synchronization signal that starts Therefore, the shift of the stereoscopic image can be prevented.

According to the image display device of the fifth aspect of the present invention, in addition to the effect of the fourth aspect of the invention, the wavefront curvature modulating means has a scanning frequency of scanning in the first direction and the second direction. It is possible to make the wavefront curvature of the light flux substantially the same during scanning in the high direction, and to modulate the wavefront curvature in synchronization with a synchronization signal that starts scanning in the low scanning frequency direction. Therefore, the frequency of the wavefront curvature modulation can be set as low as possible, and it is possible to prevent the image disturbance that occurs near the scanning line.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an overall configuration of a retina scanning display 1.

FIG. 2 is a configuration diagram showing a configuration of a wavefront curvature modulating means 100.

FIG. 3 is a schematic diagram showing a mode in which laser light is modulated by the wavefront curvature modulating means 100.

FIG. 4 is a timing chart when the cycle of modulation of the wavefront curvature of the wavefront curvature modulating means 100 in the first embodiment is twice the cycle of generation of the vertical synchronization signal 6.

FIG. 5 is a diagram showing a frame to be formed in the case of alternately forming frames in which the wavefront curvature is modulated by the wavefront curvature modulating means 100.

FIG. 6 is a diagram showing an image 32 in which two frames having a wavefront curvature a and a wavefront curvature b are combined.

FIG. 7 is a diagram showing an arrangement in the depth direction of each element that constitutes an image 32 in which two frames having a wavefront curvature a and a wavefront curvature b are combined.

FIG. 8 is a timing chart in the case where the modulation cycle of the wavefront curvature of the wavefront curvature modulating means 100 in the second embodiment is the same as the generation cycle of the vertical synchronization signal 6.

FIG. 9 is a diagram showing an image 33 having different wavefront curvatures in the vertical direction and combined.

FIG. 10 is a diagram showing an arrangement in the depth direction of each element that constitutes the image 33 that is synthesized by having different wavefront curvatures in the vertical direction.

FIG. 11 is a timing chart showing the relationship between the modulation cycle of the wavefront curvature of the wavefront curvature modulation means 100 and the generation cycle of the vertical synchronization signal 6 in the third embodiment.

12 is a timing chart showing the relationship between the change in wavefront curvature near the timing T1a in FIG. 11 and the generation cycle of the horizontal synchronizing signal 5.

FIG. 13 is a diagram showing an image 34 synthesized with different wavefront curvatures in the vertical direction and the horizontal direction.

FIG. 14 is a diagram showing the arrangement in the depth direction of each element that constitutes the image 34 that is synthesized with different wavefront curvatures in the vertical direction and the horizontal direction.

[Explanation of symbols]

1 Retina scanning display 2 Light source unit 4 video signals 5 Horizontal sync signal 6 Vertical sync signal 7 Depth signal 19 Horizontal scanning system 20 1st relay optical system 21 Vertical scanning system 22 Second relay optical system 24 pupil 30, 31 frames 32-34 images

Claims (5)

[Claims] 1. At least one light source, a modulation means for intensity-modulating a light flux emitted from the light source according to an image signal, and an optical means for making the light flux modulated by the modulation means enter an observer's pupil. Means and an image for displaying an image on the retina of the observer while scanning the light flux incident by the optical means in the first direction and the second direction substantially perpendicular to the first direction and forming a frame. The display device includes a wavefront curvature modulating unit that modulates a wavefront curvature of the light flux, wherein the wavefront curvature modulating unit includes the first direction and the second direction.
During scanning in at least one of the directions
An image display device, wherein the wavefront curvature of the light flux is modulated. 2. At least one light source, a modulation means for intensity-modulating a light beam emitted from the light source in accordance with an image signal, and optics for making the light beam modulated by the modulation means enter an observer's pupil. Means and a light beam incident by the optical means in a first direction and a second direction substantially perpendicular to the first direction to form a frame, and the frame is changed over time to perform the observation. In an image display device for displaying an image on the retina of a person, a wavefront curvature modulating unit that modulates a wavefront curvature of the light flux is provided, and the wavefront curvature modulating unit substantially reduces the wavefront curvature of the light flux in at least the same frame. The image display device is characterized in that the wavefront curvature of the light flux is modulated only when the frames are switched. 3. The image display device according to claim 2, wherein the wavefront curvature modulating means modulates the wavefront curvature of the light flux every time the frame is switched. 4. The wavefront curvature modulating means modulates the wavefront curvature in synchronism with a synchronization signal for starting scanning in the first direction or the second direction. The image display device according to any one of claims. 5. The wavefront curvature modulating means makes the wavefront curvatures of the light beams substantially the same during the scanning in the higher scanning frequency direction among the scanning in the first direction and the second direction, and the scanning frequency is The image display device according to claim 4, wherein the wavefront curvature is modulated in synchronization with a synchronization signal for starting scanning in the lower direction.