JP3761834B2 - Image display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an eyeball projection-type image display device that directly projects a transmitted light beam of a video board onto a wearer's retina. The present invention also relates to a portable eyeglass-mounted or head-mounted eyeball projection-type image display device.
[0002]
[Prior art]
As an eyeball projection type image display apparatus, an apparatus including the optical system shown in FIG. 9 has been proposed in, for example, Japanese Patent Laid-Open No. 2-136818. The optical system 30 of this image display device is held in front of the wearer's eye by a frame (not shown), and is a plurality of components arranged toward the wearer's eyeball 31, that is, a point light source 32 and a transmission that is a video board. A liquid crystal panel 33 and an eyepiece 34 are provided. In the image display device having such a configuration, the light emitted from the point light source 32 passes through the liquid crystal panel 33. An image or video formed by the light transmitted through the liquid crystal panel 33 is formed on the pupil 35 by the eyepiece lens 34 and projected onto the retina 37 through the crystalline lens 36. Thus, in this image display apparatus, the point light source 32 is configured to form an image on the pupil 35, and the directivity of the light beam is good. In addition, the image on the liquid crystal panel 33 can be clearly observed regardless of whether the wearer is nearsighted or farsighted. On the other hand, even if the wearer slightly deflects his / her eyes from the optical system 30, the luminous flux is scattered by the iris and the image cannot be observed. For example, in the case of a normal adult, the pupil diameter in a dark place is about 7 mm. Therefore, if the pupil 35 moves about ± 3.5 mm or more, an image cannot be observed. Further, since the pupil diameter is about 4 mm in a bright place, the image cannot be observed when the pupil 35 moves about ± 2 mm.
[0003]
On the other hand, a configuration in which a surface light source is disposed in close contact with a liquid crystal panel has been proposed. In this configuration, light transmitted through the liquid crystal panel is emitted in all directions, and a light beam having no directivity is guided to the pupil. Therefore, the angular component of light passing through the pupil is wide. Therefore, the aberration of the optical system that projects the light beam to the pupil must be corrected, and the configuration of the optical system becomes extremely complicated. Also, the wearer needs to focus the image on the retina with his own crystalline lens. However, since the distance between the liquid crystal panel and the pupil is limited, a person with poor vision needs to wear glasses. Furthermore, even if the wearer turns his / her line of sight from the liquid crystal panel to observe the outside world, the light transmitted through the liquid crystal panel enters the wearer's pupil, and thus the appearance of the outside world cannot be observed well. Furthermore, since it is necessary to illuminate the liquid crystal panel with a light amount that is greater than the light amount necessary for observation, power consumption increases.
[0004]
As another image display device, as shown in FIG. 10, an imaging lens 39 is disposed between the liquid crystal panel 33 and the eyepiece lens 34, and the imaging lens 39 once forms an aerial image on the intermediate imaging surface 40. There has been proposed a relay lens optical system that forms an image on the pupil 35 again with the eyepiece 34. Certainly, if this relay lens optical system is used, the optical length can be increased, so that there is an advantage that a new optical element is disposed between the imaging lens 10 and the eyepiece lens 11 and the angle of view can be easily adjusted. . However, the image display apparatus employing this relay lens optical system cannot solve the above-described problems of the optical system of FIG.
[0005]
[Problems to be solved by the invention]
Therefore, the present invention provides an image display with a simple configuration that allows the wearer to observe a clear image without adjusting the crystalline lens by himself / herself, and allows the wearer to observe the appearance of the outside world well when moving the line of sight. A device is provided.
[0006]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a an image display apparatus for projecting an image of the image plate in the retina of the eye, the image plate which transmits a light source, the light emitted from the light source, the video An imaging lens that forms an intermediate image by imaging the light transmitted through the plate, an eyepiece that forms an image formed by the imaging lens again on the retina of the eyeball, and an image formed by the imaging lens And an image display device configured to project an image emitted from the screen onto the retina of an eyeball by the eyepiece, the screen having light diffusivity only in the horizontal direction. It is characterized by having .
[0007]
In another embodiment of the present invention, when the light transmitted or reflected by the screen is sent to the eyeball by the lens, the light flux projected on the pupil plane of the eyeball is approximately 1 to 2 times the size of the pupil in the horizontal direction. The light diffusibility of the screen and the size of the light source are set so as to have a double size and approximately a pupil size in the vertical direction .
[0008]
The screen may be a transmissive screen or a reflective screen.
[0009]
It is preferable that the light source and the pupil position of the eyeball have a substantially conjugate relationship.
[0010]
The light source is preferably a white LED or a combination of red, green and blue LEDs.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a plurality of embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the member or part which is the same or respond | corresponds in several drawing which displayed several embodiment demonstrated below. In addition, in order to facilitate understanding of the invention, the following description uses terms indicating directions (for example, “up”, “down”, “right”, “left”, and terms including them). The invention described in the scope of the present invention is not limitedly interpreted by the meanings of these terms.
[0015]
Embodiment 1 FIG.
As shown in FIG. 1, an eyeball projection type image display device 1 according to the present invention is a person (image observer or wearer 2) who attaches detachably to the head and observes an image (moving image or still image). An optical unit 3 that projects an image onto the eyeball of the wearer 2 and a head of the wearer 2 to stably support the optical unit 3 in front of the eye. The frame 4 is held in the unit, and a video signal transmission unit 5 that transmits the video signal to the optical unit 3. The video signal transmission unit 5 is built in the frame 4. However, the configuration of the frame 4 and the arrangement of the video signal transmission unit 5 are merely examples, and the present invention is not limited to the configuration illustrated.
[0016]
The internal structure of the optical unit 3 that is the most characteristic feature of the present invention is shown in FIG. As shown in the figure, a light source 8, a transmissive image board 9, an imaging lens 10, and an eyepiece lens are provided on the housing 6 (see FIG. 1) of the optical unit 3 toward the right or left eyeball 7 of the wearer 2. 11 and the image forming lens 10 and the eyepiece 11 constitute a relay lens optical system.
[0017]
Various light emitting devices can be used as the light source 8. In this embodiment, a number of light emitting diodes (LEDs) are two-dimensionally arranged along a plane perpendicular to the optical axis 12 connecting the light source 8 and the eyeball 7. A surface light source arranged in the above is used. As the light emitting diode, a diode emitting ultraviolet light or blue light can be used.
As the transmission type video board 9, a transmission type liquid crystal panel is used. The liquid crystal panel is constituted by a full-color liquid crystal panel or a monochrome liquid crystal panel, and is electrically connected to the video signal transmission unit 5 so as to display an image based on the video signal output from the video signal transmission unit 5. It is.
As the imaging lens 10 and the eyepiece 11, a spherical or aspheric convex lens is usually used. The imaging lens 10 and the eyepiece lens 11 can be configured by a single lens, but may be a combined lens configured by combining a plurality of lenses.
The distance between the imaging lens 10 and the eyepiece lens 11 is determined so that an image transmitted through the imaging lens 10 can be once formed as an aerial image on the intermediate imaging surface 13 between the lenses as shown in the figure. Yes.
[0018]
As shown in the drawing, the light source 8, the transmission type image board 9, the imaging lens 10, and the eyepiece lens 11 are placed between the light source 8 and the wearer while sandwiching the eyepiece lens 11 with the wearer 2 wearing the image display device 1. The two pupils 14 are arranged so as to form a conjugate relationship. Further, as shown in FIG. 3, the size [A] of the light beam 17 at the position of the pupil 14 (pupil plane) [A ≦ A so that the size [A] of the pupil 14 is equal to or twice the size [a]. ≦ 2a], the size of the light source 8, the position of the surface light source 8, the transmission type image board 9, the imaging lens 10, the eyepiece 11 and the eyeball 7 are determined.
[0019]
According to the display device having the above configuration, the light emitted from the light source 8 is transmitted through the image plate 10 and is imaged on the intermediate imaging surface 13 by the imaging lens 10. Further, the image transmitted through the imaging lens 10 is converged to the position (pupil plane) of the pupil 14 of the wearer 2 or the vicinity thereof by the eyepiece lens 11 and projected onto the retina 16 by the crystalline lens 15.
[0020]
As described above, according to the image display device 1 of the present embodiment, the video displayed on the video board 10 is converged on the pupil 14 or the vicinity thereof to be in the Maxwell vision state. Even so, the image can be clearly observed without adjusting the crystalline lens 15 by itself. Naturally, a person who normally wears glasses can clearly observe the image regardless of whether or not the glasses are worn. In addition, the range that can be seen when the line of sight is moved can be accurately limited. Then, when viewing the image with the eyes of the person wearing the image display device 1 while viewing the scenery with the eyes of the person not wearing the image display device 1, it is possible to easily superimpose these views and the images.
[0021]
Further, if the light source 8 is rectangular, in particular, long in the left-right direction of the wearer 2 and short in the vertical direction, as shown in FIG. 4, the light beam 18 that converges at or near the pupil 14 is long in the horizontal direction. The oval shape is short in the vertical direction. Further, as shown in the figure, if the major axis width [B] of the elliptical luminous flux 18 is about twice the pupil diameter [a] and the minor axis width [C] is substantially equal to the pupil diameter [a], the wearing is performed. Even when the person 2 moves his / her line of sight to the left and right, the image can be clearly observed. On the other hand, when the wearer 2 slightly moves his / her line of sight up and down, the pupil 14 is out of the luminous flux and the image cannot be observed. Therefore, as shown in FIG. 1, the wearer 2 can switch to a state in which only the scenery of the outside world is observed by moving the line of sight slightly up and down while observing the image while walking.
[0022]
Furthermore, since the relay lens optical system including the imaging lens 10 and the eyepiece 11 is employed in the first embodiment, the optical path length can be set long, and the angle of view can be adjusted between these lenses. An optical element can be arranged.
[0023]
Furthermore, since the image forming lens 10 forms an image smaller than the image displayed on the liquid crystal panel on the intermediate image forming surface 13, the optical system in front of the eyes (in particular, the eyepiece lens 11) is reduced and mounted. One can secure a wide field of view.
[0024]
In the first embodiment, a transmissive liquid crystal panel is used as the video board 9, but a reflective image display device, a film, or the like can also be used.
[0025]
Embodiment 2. FIG.
In the first embodiment, a surface light source is used as the light source, but a point light source or a surface light source close to a point light source may be used as the light source. In this case, as shown in FIG. 5, a transmissive screen 18 for diffusing light is provided on an intermediate imaging surface between the imaging lens 10 and the eyepiece lens 11, and the light is diffused by the transmissive screen 18. Is preferred. As the transmissive screen 18, a resin plate, ground glass, paper, or the like in which scattering particles such as metal powder are appropriately mixed in a transparent resin can be used.
[0026]
According to the image display device having such a configuration, the light diffused by the transmissive screen 18 is converged on or near the pupil plane and then projected onto the retina 16. Therefore, by controlling the diffusibility of the transmissive screen 18, the size of the light beam formed on the pupil plane can be controlled so that the wearer can recognize the image when he / she wants to see the image, and deliberately looks at the line of sight. The image display device can be designed so that the image cannot be recognized when deviating.
[0027]
Embodiment 3 FIG.
In the image display device according to the second embodiment, the transmissive screen 18 has diffusibility only in the horizontal direction (left and right direction of the wearer) as shown in FIG. 6A, and as shown in FIG. 6B. A screen having no diffusibility in the vertical direction (vertical direction of the wearer) may be used. In this case, the light flux converged on the pupil 14 or its vicinity draws an ellipse that is long in the horizontal direction and short in the vertical direction (see FIG. 4). Therefore, even when the wearer moves his / her line of sight to the left or right, the wearer can observe the image clearly. Also, the wearer can switch to a state in which only the scenery of the outside world is observed by moving the line of sight slightly up and down.
[0028]
Embodiment 4 FIG.
An image display apparatus according to the fourth embodiment is shown in FIG. In this image display device, a reflective screen 19 is used as a screen disposed on the intermediate image plane. The reflective screen 19 can be any material that can scatter light, such as a white resin plate, a plate of resin or glass or metal coated with white or silver paint or fluorescent paint, or ground glass. . A beam splitter 20 is disposed between the imaging lens 10 and the reflective screen 19 so as to form an angle of approximately 45 degrees with the optical axis 12.
[0029]
According to the image display device having such a configuration, the light emitted from the light source 8 passes through the video plate 9, the imaging lens 10, and the beam splitter 20, and then forms an image on the reflective screen 19. The formed image is reflected by the reflective screen 19, then reflected again by the beam splitter 20, passes through the eyepiece lens 11, and re-images on the pupil plane. The re-imaged image is projected onto the retina 16.
[0030]
Therefore, according to the image display device of the present embodiment, a light source having a point light source or a light emitting region close to a point light source is used as the light source 8, and the light emitted from the light source is efficiently applied to the video board 9, An image transmitted through the video plate 9 can be imaged on the reflective screen 19 on the intermediate image plane. Therefore, not only the light use efficiency is increased, but also the size of the light beam on the pupil plane is controlled by controlling the diffusivity of the reflective screen 19 on the intermediate image plane so that the wearer can view the image. The image can be recognized only when desired, and the image cannot be recognized if the line of sight is deliberately deviated.
[0031]
In addition, since the relay lens optical system is used, the setting of the angle of view and the like can be easily changed by setting a long optical path length and arranging necessary optical elements. Further, since an image smaller than the image displayed on the video board 9 is formed on the screen 19 of the intermediate image formation surface, the optical system in front of the eyes (particularly the eyepiece 11) is made small so that the wearer has a wide field of view. Can be secured. Furthermore, by using a reflective screen, the utilization factor of light can be increased compared to a transmissive screen.
[0032]
Embodiment 5. FIG.
FIG. 8 shows an image display apparatus according to the fifth embodiment, which is an improvement of the image display apparatus according to the fourth embodiment. In this image display device, a polarization beam splitter 21 is used as the beam splitter. The transmission polarization direction of the polarization beam splitter 21 is matched with the transmission polarization direction of the liquid crystal panel forming the image plate 9. In addition, a ¼ wavelength plate (λ / 4 wavelength plate) 22 is disposed between the polarization beam splitter 21 and the reflective screen 19 to give a constant optical path difference (phase difference) between the two polarization components. ing.
[0033]
According to the image display device having such a configuration, the transmission polarization direction of the polarization beam splitter 21 and the transmission polarization direction of the liquid crystal panel as the video plate 9 coincide with each other. Loss can be minimized. Further, the quarter wavelength plate 22 can make the polarization direction of the light that is reflected by the reflective screen 19 and incident again on the polarization beam splitter 21 be orthogonal to the polarization direction of the light transmitted through the polarization beam splitter 21. Therefore, the light reflection loss at the polarization beam splitter 21 can be minimized. Therefore, it is possible to realize an image display device having a high light utilization rate.
[0034]
In the image display apparatus described above, the color (wavelength component) emitted by the light source is not particularly limited, but it is preferable to use a light source (for example, a white LED) that emits white light.
The light source is not limited to a single light source that emits a single color (wavelength), but may be a plurality of light sources that emit red, green, and blue colors. In this case, a so-called sequential type liquid crystal panel that can switch the liquid crystal display image in synchronization with the timing of switching the emission color can be used.
[0035]
【The invention's effect】
As is apparent from the above description, the image display device projects the image of the image board onto the retina of the eyeball, and includes a light source, an image board that transmits light emitted from the light source, and light that passes through the image board. And an eyepiece that re-images the image formed by the imaging lens on the retina of the eyeball, and the light beam projected on the pupil plane of the eyeball is, According to what the size of the light source is set so as to have a size of about 1 to 2 times the size of the pupil, it is possible to configure the image to be invisible when the pupil is moved beyond the pupil diameter, An image display device that can be seen when the wearer wants to see an image and disappears when the user deliberately deviates the line of sight can be realized. Further, since the relay lens optical system is used, the optical path length can be set long, the space for arranging the optical elements can be secured, and the setting change of the angle of view and the like can be easily performed. Furthermore, by forming an image smaller than the image on the liquid crystal panel with the imaging lens on the intermediate imaging plane, the optical system in front of the eyes can be reduced, and the wearer can ensure a wide field of view when wearing. .
[0036]
An image display device for projecting an image of a video board onto a retina of an eyeball, wherein an intermediate image is formed by imaging a light source, a video board that transmits light emitted from the light source, and light transmitted through the video board. An imaging lens to be obtained, an eyepiece for re-imaging the image formed by the imaging lens on the retina of the eyeball, and a screen disposed on the intermediate image plane imaged by the imaging lens According to the configuration in which the image projected from the screen is projected onto the retina of the eyeball by the eyepiece lens, an image smaller than the image on the video plate is further formed on the intermediate imaging plane by the imaging lens. Thus, the optical system in front of the eyes can be reduced, and the wearer can ensure a wide field of view when wearing.
[0037]
In addition, the configuration of the image display device using a transmissive screen as the screen can be simplified.
[0038]
Further, in an image display device using a reflective screen as the screen, the light utilization rate can be improved as compared with a transmissive screen.
[0039]
Furthermore, by arranging a polarizing beam splitter and a quarter-wave plate between the imaging lens and the reflective screen, the light utilization rate can be further improved.
[0040]
Furthermore, if the screen is configured to have diffusibility only in one direction, for example, the horizontal direction, the wearer turns his / her eyes up and down, and the image becomes invisible (or the light intensity becomes weak), but the pupil is in the horizontal direction. Since the image can be seen even if it is displaced, it is easy for the wearer to wear (easy to see).
[0041]
When the light transmitted through or reflected by the screen is sent to the eyeball by the lens, the light beam projected on the pupil plane of the eyeball has a size about 1 to 2 times the size of the pupil in the horizontal direction. According to the image display device in which the light diffusibility of the screen and the size of the light source are set so as to have approximately the size of the pupil in the vertical direction, the image can be obtained even if the pupil is moved about the pupil diameter in the horizontal direction. However, if the pupil is moved by about the pupil diameter in the vertical direction, it is possible to make the image invisible, easy for the wearer to wear (horizontal direction), and if the pupil is intentionally deflected, the image cannot be seen and is not in the way (vertical) (Direction) Image display device can be realized.
[0042]
In addition, in a configuration in which the light source and the pupil position of the eyeball are in an approximately conjugate relationship, an image of the approximate light source can be copied to the pupil position, and the range that can be seen when the pupil is moved can be accurately limited.
[0043]
Furthermore, when the light source is a white LED, illumination can be performed with one light source, and the number of components can be reduced.
[0044]
A field sequential type liquid crystal panel can be used by configuring the light source with a combination of red, green and blue LEDs.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a use state of an image display device according to the present invention (FIG. 1A), and a perspective view showing an appearance of the image display device (FIG. 1B).
FIG. 2 is a side view showing a first embodiment of an optical system included in the image display device.
FIG. 3 is a front view showing a circular light beam projected on an eyeball.
FIG. 4 is a front view showing an elliptical light beam projected on an eyeball.
5 is a side view showing a configuration of an optical unit incorporated in an image display apparatus according to Embodiment 2. FIG.
6 is a plan view (FIG. 6A) and a side view [FIG. 6B] showing a configuration of an optical unit incorporated in an image display apparatus according to Embodiment 3. FIG.
7 is a side view showing a configuration of an optical unit incorporated in an image display device according to Embodiment 4. FIG.
8 is a side view showing a configuration of an optical unit incorporated in an image display apparatus according to Embodiment 5. FIG.
FIG. 9 is a front view showing a configuration of an optical system in a conventional image display apparatus.
FIG. 10 is a front view showing a configuration of another optical system in a conventional image display apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1: Image display device 2: Wearer 3: Optical part 7: Eyeball 8: Light source 9: Image board 10: Imaging lens 11: Eyepiece lens 13: Intermediate imaging surface 14: Pupil 17: Light beam 18: Transmission type screen 19 : Reflective screen 20: Beam splitter 21: Polarizing beam splitter 22: 1/4 wavelength plate

Claims (7)

An image display device that projects an image of a video board onto the retina of an eyeball,
A light source;
An image board that transmits light emitted from the light source;
An imaging lens that forms an intermediate image by imaging light transmitted through the image plate;
An eyepiece that re-images the image formed by the imaging lens on the retina of the eyeball ;
A screen disposed on the intermediate image plane imaged by the imaging lens,
In the image display device configured to project the image that has emerged from the screen onto the retina of the eyeball by the eyepiece lens,
An image display device, wherein the screen has light diffusibility only in a horizontal direction . When the light transmitted through or reflected by the screen is sent to the eyeball by the lens, the light beam projected on the pupil plane of the eyeball has a size of about 1 to 2 times the size of the pupil in the horizontal direction, 2. The image display device according to claim 1, wherein the light diffusibility of the screen and the size of the light source are set so as to have a pupil size in the vertical direction . The screen, the transmission type image display apparatus according to claim 1 or 2, characterized in that a screen. The screen, the image display apparatus according to claim 1 or 2 characterized in that it is a reflective screen. 4. The image display device according to claim 1, wherein the light source and the pupil position of the eyeball have a substantially conjugate relationship . 5. 6. The image display device according to claim 1, wherein the light source is a white LED . 6. The image display device according to claim 1, wherein the light source is a combination of red, green, and blue LEDs .

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