JP2000019450A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device which is made small in size, light in weight and thin in thickness, improved in mounting stability and designing potential, and has high-quality and stable visual field characteristic. SOLUTION: This device has an optical system effectively folding a light beam including image information from display modules 22a and 22b by using composite prisms 24a and 24b and is constituted by arranging the display modules 22a and 22b and an enlarging optical system in parallel. Thus, an unnecessary projecting part is eliminated and the entire optical system is thinned. Furthermore, the device is thinned and made light in weight by adopting structure to divide visual field by using two display modules 22a and 22b and two composite prisms 24a and 24b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device having a function of displaying an enlarged image by a virtual image for monitoring a moving image or a still image.

[0002]

2. Description of the Related Art Various information devices, especially devices capable of handling visual information by means of liquid crystal or photoelectric image display means, have made remarkable progress.
In addition, information processing machines for personal use, which are so-called mobile devices that can be used anywhere and at any time, have been remarkably developed. The performance required of this mobile device is a compact package with good portable performance, high information processing speed, a large number of processing functions, etc., and more accurate information in a limited space of a small device. There is a need for a means for displaying the information in an easily understandable manner. At present, liquid crystal display means and the like that fill the entire surface of the device are mainstream, but there is no possibility of following the miniaturization of the device.

[0003] As one of the effective display methods, a head-mounted display, a finder display and the like have attracted attention in recent years, and much research and development of devices have been advanced.

[0004] It is a method of enlarging an image such as a moving image or a still image on a display device by a photoelectric device such as a substantially small liquid crystal or plasma as a virtual image, and visually projecting it as an apparently larger screen than an actual display screen. , Device. By enlarging a small display device as a virtual image, there is an advantage that the size of the device can be reduced, the power consumption of the device, and the price can be suppressed, and an apparent display screen can be greatly presented regardless of the size of the device. Today, with the improvement of resolution, contrast, brightness, performance of magnifying optics, and image processing technology of small display devices, high-performance magnified display devices are being used in various devices and scenes. Was.

FIGS. 6 to 10 show an optical system used in a conventional head mount.

First, FIG. 6 is a configuration diagram of an optical system of a conventional display device. FIG. 6 shows a display device of a conventional eyepiece optical system using a refractive lens type. Similar to the monitoring finder optical system of many video camcorders, one or a plurality of lenses are combined to project a virtual image visually with positive refracting power. Although the structure is simple, and it is lightweight as an optical system having a relatively small angle of view, it is widely used in general. However, the structure is slightly larger in the optical axis direction of the optical system. In the figure, a display image (not shown) drawn on a display module 1 composed of a small liquid crystal or the like is converted into a virtual image which is enlarged by the entire lens group 2 having a positive refractive power composed of a plurality of lenses for correcting various aberrations. This is to project the eye 4 in the optical axis 3 direction of the group.

Next, FIG. 7 is a configuration diagram of a conventional concave mirror reflection type display device. A display image (not shown) drawn on the display module 1 in FIG. 7 is first reflected by the half mirror unit 5 and converged by the concave mirror 7 arranged on the optical axis 6, and again the half mirror unit 5 A virtual image of a transmitted and enlarged display image (not shown)
Is projected to the eye 4. By using the concave mirror 7, the configuration of the optical system can be folded, and the overall configuration can be realized compactly. In addition, there are advantages in that the coma aberration and the chromatic aberration of magnification can be suppressed due to the principle of the optical system. Therefore, the viewing angle of view can be generally as large as about 40 degrees, and a relatively wide screen can be observed.

Next, FIG. 8 is a configuration diagram of the display device of FIG. 7 using a half mirror. FIG. 8 shows a structure in which the half mirror shown in FIG. 6 is opposed to the concave mirror, and the optical path reciprocates in the optical axis. This makes it possible to make the optical system more compact. In FIG. 1, a display image (not shown) drawn on the display module 1 is transmitted through a concave mirror 8 made of optically rotatory glass having a semi-transparent polarizing film provided on an incident surface, and then incident on the concave mirror 8. It is possible to project an enlarged virtual image of the displayed image to the eye 4 while being reflected by the half mirror 9 made of a polarizing film having a polarization axis perpendicular to the polarization axis of the polarized light, reflected again by the concave mirror 8 and converged. it can. Further, by disposing the polarizing element in this manner, a direct display image (light ray) from the display module 1 can be removed. According to this method, a wide angle of view of 40 degrees or more can be obtained, and the generation of aberration can be suppressed to a relatively small value.

FIG. 9 is a block diagram of an eccentric concave mirror type display device. In FIG. 9, a virtual image of a display image (not shown) of the display module 1 can be projected to the eyes 4 by a concave mirror 10 having an optical axis decentered from the line of sight disposed in front of the eyes. Further, since a light beam with a wide angle of view can be sent to the eyeball and the optical path can be taken out without using a half mirror unlike the prior art, almost 100% of the light quantity from the display module 1 can be used. Since the display module 1 is simple in configuration and can be arranged on the side of the axis of the line of sight, a compact display device as a whole can be realized.

[0010] An optical system based on this concept and having a prism having an eccentric concave mirror has been disclosed. FIG.
10 is a configuration diagram of the display device of FIG. 9 using a prism. As shown in FIG. 10, the display module 1 is disposed diagonally above the eye, and the light of the display image (not shown) of the display module 1
And is reflected by the first internal reflection surface 12 that satisfies the condition of total reflection, and the same curved surface as the first internal reflection surface 12 while converging the reflection therefrom by the second internal reflection surface 13. Then, an enlarged virtual image of the display image is projected through the exit surface 12 formed by the optical system and is visually recognized by the eye part 4. As described above, since there is no half mirror or blocking member in the middle of the optical path, the display image can be observed with high efficiency, that is, a bright image. Although a chromatic aberration does not occur in principle because a virtual image is created by reflection, the reflecting surface, especially the inner reflecting surface 2, is largely decentered, and thus an eccentric aberration occurs. In order to improve this, a three-dimensional aspherical surface (hereinafter, a free-form surface) which is a non-rotation object is adopted.

Here, the free-form surface will be described a little more. Assuming that the drawing sheet is a generatrix section and a plane perpendicular to the drawing sheet is a sagittal section, the rotationally symmetric spherical and aspherical surfaces have a radius of curvature in the generatrix section and the sagittal section. Are equal, and the focal lengths of both sections are the same. However, in a non-rotationally symmetric free-form surface, the radii of curvature of the generatrix section and the sagittal section are different, and naturally the focal lengths of both sections are also different. By employing a free-form surface having such a property for a plurality of prism surfaces, eccentric aberration can be favorably corrected. In order to match the aspect ratio between the display module 1 and its virtual image, the focal lengths of the meridional section and the sagittal section of each prism surface are appropriately set, and the focal lengths of the whole system and the sagittal section of the free-form surface prism are set. The focal lengths are set to be the same.

[0012]

However, problems to be solved in the above-described virtual image projection type display device will be described.

First, in the case of a refraction lens with a straight axis, the distance in the direction of the optical axis directly defines the size of the display device, so that it is difficult to make the display device compact. Contrary to this, if the size is to be reduced, performance such as the viewing angle and the size of the pupil will be reduced. Further, since the virtual image is projected only by the refraction system, the viewing angle is relatively small and the size of the pupil is also small. This is because coma aberration and chromatic aberration of magnification occur, and the reason why the angle of view is about 20 degrees or more is that the occurrence of these aberrations degrades the peripheral image quality.

Next, in a concave mirror type in which a display module is arranged on a side portion, the same type can reduce the entire configuration as compared with the above-mentioned refractive lens type because the optical path is folded, and the head mount display device is used. Although it is possible to realize a small size and light weight and a good mounting balance, it is necessary to provide a half mirror for extracting a light beam from the reciprocating optical path since the optical path reciprocates. It will be as follows. In order to further widen the angle of view, there is a problem in correcting the curvature of field generated by the concave reflecting mirror, and it is difficult to obtain an observation angle of view of about 40 degrees or more. Further, there is a disadvantage that the entire configuration is suddenly increased in size when the angle of view is widened due to the presence of a half mirror arranged in an inclined manner.

In the type having the same concave mirror and facing the half mirror, although it has a potential to widen the angle of view, an isolator system using a polarizing element is used to cut off a light beam from the image display module directly entering the eyes. The optical system must be assembled, and the optical system becomes complicated, which affects adjustment man-hours and costs. Further, it is difficult to obtain a polarizer having good polarization characteristics and efficiency over the entire use wavelength range, and there is a problem that image quality is reduced and luminance is insufficient.

Finally, with respect to the decentered concave mirror type, including the type using a prism, a compact and efficient optical system capable of obtaining a light quantity of almost 100% can be realized. It is necessary to correct astigmatism, coma, and image plane tilt. Further, if an aspherical optical system is used for these corrections, there is a problem in that design and mirror finishing are difficult.

The present invention solves the above-mentioned problems, and realizes a smaller, lighter, and especially thinner overall configuration of a display device to enhance mounting stability and design potential, and has high quality and stable visual field characteristics. It is an object to provide a display device.

[0018]

In order to achieve the above object, the present invention provides an image display means for displaying an image in a liquid crystal or photoelectric manner, and an optically magnified image by the image display means. A display device comprising an image magnifying means for optically bending the optical path from the image display means to the image magnifying means, wherein the optical prism means is substantially flat with a display screen of the image display device. Opposed in a non-contact manner on the incident surface consisting of, furthermore, after bending the optical path incident on the optical prism means from the image display device on the first internal reflection surface consisting of a flat or curved surface inside the optical prism means, After being bent at the second inner reflection surface made of a substantially flat surface and further bent at the third inner reflection surface made of a flat surface or a curved surface, from the same plane as the incident surface. That is emitted from the optical prism unit by passing through the exit surface, it is made of is projected further said enlarged by the image enlarging means.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to an image display means for displaying an image in a liquid crystal or photoelectric manner, and a method for optically enlarging an image by the image display means for trial inspection. An image enlargement means, and a display device comprising an optical prism means material having a function of bending an optical path from the image display means to the image enlargement means,
The optical prism means is opposed to the display screen of the image display device in a non-contact manner on an incident surface which is substantially flat, and further passes an optical path incident from the image display device into the optical prism means on a plane inside the optical prism means. Or, after bending at the first internal reflection surface having a curved surface, bending at the second internal reflection surface having a substantially flat surface, further bending at the third internal reflection surface having a flat surface or a curved surface, the same as the incident surface The display device is characterized in that the light is emitted from the optical prism means by passing through an emission surface formed within a plane, and is further enlarged and projected by the image enlargement means. This makes it possible to effectively bend light rays from the image display module, and to make the optical system of the display device small and light, In which it is possible to reduce the line-of-sight direction of the height.

According to a second aspect of the present invention, the image enlarging means is made of a dielectric member having a positive refractive power and provided in non-contact with the exit surface of the optical prism means. By having a refractive power of, an enlarged virtual image of the display module can be projected visually. In addition, the focal length and the like can be adjusted independently of the optical prism means, and a stable visual field characteristic can be obtained without any influence on the total reflection condition on the second reflection surface because of non-contact. It is.

According to a third aspect of the present invention, the image enlarging means comprises a convex lens, an aspherical optical system, a Fresnel lens, or a hologram lens. It is possible to provide a refracting power, to embody the invention of claim 2, and to obtain a stable visual field characteristic.

According to a fourth aspect of the present invention, there is provided a dielectric multilayer film in which a part of light from the outside of the optical prism means can be incident on the first internal reflection surface in the optical prism means. , Or a semi-permeable membrane made of a metal film, so that a part of light from the outside of the optical prism means can be taken into the prism, and visual information of the surrounding environment can be obtained within the visual field to be observed. It can be incorporated.

According to a fifth aspect of the present invention, there is provided a concave lens or a Fresnel lens for offsetting a positive refracting power of the image enlarging means on the outside of the first internal reflection surface across the semipermeable membrane. And a liquid crystal for arbitrarily shielding the light transmitted through the semi-permeable membrane, or a mechanical light shielding unit is provided. By doing so, the visual information of the surrounding environment distorted by the positive refracting power of the image enlarging means is corrected, and by providing the shielding means, when the visual information of the surrounding environment is unnecessary, it is cut off. Is what you can do.

According to a sixth aspect of the present invention, in the optical prism means, the second internal reflection surface is substantially a plane which is the same as the incident surface and the exit surface. By doing so, the bending optical system can be effectively configured, and the whole can be compactly configured.

According to a seventh aspect of the present invention, the optical prism means is sandwiched between the optical axis or the center of the line of sight of the image enlarging means, and the two exit surfaces are arranged in parallel and substantially in contact with each other. The two fields of view are each synthesized by one image enlarging means so as to correspond to one field of view. By doing so, the optical prism means is moved in the optical axis direction of the image enlarging means. It can be configured to be small and thin, so that the mounting balance is adjusted and a feeling of mounting that is stable and less fatigued can be realized.

According to an eighth aspect of the present invention, the two optical prism means arranged in parallel are integrally formed of optical glass or transparent resin. With this configuration, it is not necessary to adjust the two optical prism means, and a stable field of view can be secured without being shifted from each other even during use.

According to a ninth aspect of the present invention, the image display means is arranged close to the periphery of the optical axis of the image enlarging means, and each corresponds to the optical prism means. The image display means is arranged at the peripheral edge in this way, so that the whole configuration can be realized compactly. Further, the more the image display means is provided and arranged one by one so as to correspond to the optical prism means, the more stably a wider field of view can be obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a configuration diagram of a display device according to Embodiment 1 of the present invention. In FIG. 1, the display device of the present invention has a shape similar to the shape of eyeglasses for correcting diopter in appearance, and outputs two head portions 21a and 21b by bringing them close to or in contact with both eyes. It is configured to read the displayed enlarged image display. The head unit 21 includes liquid crystal having a function of forming a display image or display modules 22a and 22b made of photoelectric means, an image magnifying lens 23a for optically enlarging an image of the display module, b, compound prisms 24a and 24b having an action of bending an optical path to form a compact head section, and a small circuit section 25 for driving a display module are incorporated.

Further, an ear hook for stably fixing the head portion to the head and a signal cable lead-out portion provided along the ear hook are provided. The signal cable lead-out portion 26 is installed so as to be guided to the rear part of the ear hook so that the signal line at the time of mounting does not become troublesome on the face.
Further, an adjustment mechanism 27 is provided so that the interval between the two heads, that is, the interval between the eyepiece windows can be adjusted at the center portion according to the convergence of the wearer.

Next, the structure and operation of the periphery of the main optical system will be described with reference to FIGS.

FIG. 2 is a structural diagram of the optical system of the display device of FIG. In FIG. 2, power is supplied from a backlight power supply 28 provided outside, and a necessary light beam is emitted from a backlight device 29. Further, an image is formed by the small display module 31 having the function of reproducing the image information signal from the external image processing module 30 as an image. When the light emitted from the backlight 29 passes through the display module 31, a light including image information is formed.

This light beam enters the prism from an incident surface 33 which is a part of the side surface of the compound prism 32 having a substantially triangular pyramid shape, is reflected by a first internal reflection surface 34 and is incident on the destination incident surface 33.
And reaches the second internal reflection surface 33 formed of the same surface. The light ray reflected again by the second internal reflection surface 33 is further reflected by the third internal reflection surface 35, and is combined with the light incident surface 33 and the exit surface 33 formed on the same plane as the second internal reflection surface 33. The light exits the prism 32. The emitted light beam is projected as a visually enlarged virtual image on the screen of the display module 31 by the image magnifying lens 36 mainly composed of a convex lens. The first and third inner reflection surfaces 34 and 35 are coated with a metal such as silver or aluminum to increase the reflectance of light rays, or are coated with a dielectric multilayer film. Has been given.
Further, the above-described incident surface 33, second inner reflection surface 33, and exit surface 33 are not particularly subjected to the above-described coating treatment for increasing the reflectance.

This is because not only is there no need for reflection processing at the time of incidence and emission, but also the angle of incidence of light rays reaching the internal reflection surface with respect to the same surface is as large as approximately 60 degrees, and the total angle defined by Snell's law is large. All rays incident to satisfy the reflection condition are reflected inside the compound prism 32 without leaking outside the compound prism 32. Therefore, a coating process for increasing the reflectance becomes unnecessary. The angle of incidence of the light rays incident on the first and third internal reflection surfaces 34 and 35 on the same surface is as small as 30 degrees, so that the total reflection condition cannot be satisfied. Coating is required. Further, the first inner reflection surface 34 and the third inner reflection surface 35 are subjected to a coating process having different functions. This will be described in more detail with reference to FIG.

In the figure, the first inner reflection surface 34 is mainly subjected to the above-mentioned metal film coating treatment with silver, aluminum, or the like in order to obtain a reflectance as high as possible of 100%. However, the third inner reflection surface 35 is set so that the reflectance is in the range of about 30% to 70%, and the remaining light rays are transmitted to the outside of the compound prism 32. This is an adverse effect for making the image of the display module 31 look bright. However, it is necessary to install a see-through mechanism capable of directly viewing an important external environment as a display device, and to improve safety and work efficiency of a wearer.

Without this see-through mechanism, the user is visually completely separated from the external environment, and cannot respond to changes in the external environment and cannot secure safety. Further, when it is necessary to recognize the external environment at the time of switching work, the display device must be removed each time, which is a problem in terms of work efficiency. For this reason, the third inner reflection surface 35 is not a perfect reflection surface but a half mirror that transmits some light rays to the outside.

Further, the see-through mechanism will be described with reference to FIG. FIG. 3 is an enlarged view of a main part of the display device of FIG. In FIG. 3, a display module (not shown)
From the third prism while propagating inside the compound prism 32.
Are reflected by the inner reflection surface 35 and reach the image magnifying lens 36. Further, as described above, the third internal reflection surface 35 is formed of a half mirror surface and has a function of reflecting a part of the incident light beam and transmitting the remaining light beam, so that a part of the light beam from the outside can be transmitted. As shown in FIG.
Is transmitted through a liquid crystal shutter section 38, a wavefront compensating prism 39, and a third internal reflection surface 35 which is a half mirror, passes through the inside of the composite prism 32, and transmits an image magnifying lens 36.
And reaches the eye (not shown).

Here, the structure and operation of the liquid crystal shutter 38 and the wavefront compensation prism 39 will be described. The liquid crystal shutter 38 simply controls the amount of transmitted light.
A screen from a display module (not shown) is projected, and light rays are increased from the outside as the liquid crystal shutter 38 is opened.
It is possible to present the external situation more clearly. In addition, the wavefront compensation prism 39 having a substantially triangular pyramid shape close to the third internal reflection surface 35 has a normal line inclined by approximately 30 degrees with respect to the line of sight of the third internal reflection surface 35. When direct rays are introduced, the external scene apparently shifts to the right, which is inconvenient for recognition or work. A concave surface 40 having a negative refractive power is provided at the tip to compensate for a wavefront transmitted through the image magnifying lens 36 having a positive refractive power, while having an action of compensating the direction of the line of sight. This is to cancel the refractive power so that the light ray reaches the line of sight as a natural situation.

In the first embodiment of the present invention, the eyeglasses are used. That is, an enlarged virtual image is projected by both the left and right eyes, but a form having a high design potential can be realized even when worn with one eye due to its small size and light weight without necessarily corresponding to both eyes.

(Embodiment 2) Embodiment 2 of the present invention will be described with reference to FIG. FIG. 4 is a configuration diagram of an optical system of a display device according to Embodiment 2 of the present invention.
FIG. 4 shows a top view of a composite prism 41, which is a main part of the display device, and a peripheral portion thereof. FIG. 4 shows a state in which the composite prism 32 in the first embodiment described above is divided into two. And two display modules 4 to accommodate the divided field of view.
2a and 2b are provided. Backlight devices 43a and 43b are installed behind the two display modules 42, respectively, and serve as light sources that propagate images on the display modules 42 as light rays. Further, the propagation structure and operation in each of the two optical paths are the same as in the first embodiment. However, the two internal reflection surfaces 44a and 44b immediately below the display module 42 are formed by applying a metal film such as silver or aluminum or a dielectric multilayer film for increasing the reflectance, and the two internal reflection surfaces immediately below the magnifying optical system. The surfaces 45a and 45b have a half mirror surface set so that the reflectance is in the range of about 30% to 70% and the remaining light rays are transmitted to the outside of the compound prism 41.

In the second embodiment, since the field of view is divided into two, one combined field of view must be realized. Therefore, the two display modules 42a, b
The image (not shown) displayed in 2 is the image to be synthesized.
It is displayed corresponding to the divided image. By combining these, a natural image with no apparent discomfort can be visually projected.

A see-through mechanism having the same structure and operation as the see-through mechanism described in the first embodiment is provided so that an external situation can be directly visually recognized. In the figure, a light beam from the outside of the display device passes through the surfaces 45a and 45b through the liquid crystal shutter 46, the wavefront compensation prism 47, and the two half mirrors, passes through the inside of the composite prism 41, passes through the image magnifying lens 36, and passes through the eye ( (Not shown). Also, two internal reflection surfaces 45a,
The wavefront compensating prism 47 having a substantially triangular pyramid shape approaching b has a shape approaching each of the two internal reflection surfaces 45a and 45b. It has a structure that negates power. As a result, an external natural situation reaches the line of sight.

As described above, by adopting a structure in which the two divided visual fields are combined as in the second embodiment of the present invention, the volume of the compound prism can be reduced by almost half, and the entire optical system can be made thinner. It can be realized as a lightweight, substantially symmetric and well-balanced one.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a configuration diagram of an optical system of a display device according to Embodiment 3 of the present invention.
FIG. 5 shows a top view of the compound prism 49, which is the main part of the display device, and its peripheral part, which is composed of the embodiment of the first embodiment described above. In order to realize the system, the symmetry of the compound prism 49 is broken, and a precision Fresnel lens or a planar optic such as a hologram lens is used for the magnifying lens 50.

By adopting such a configuration, the optical system can be made thinner and lighter, the mounting performance of the display device can be improved, and a high design potential can be realized. The operation of the prism on the image light beam is the same as that of the previous two embodiments, so that the detailed description is omitted.

Next, the structure and operation of the image magnifying lens 50 made of planar optics will be described.
In the figure, a wavefront conversion blade 51 having a sawtooth cross section is formed concentrically (not shown) on an optical axis on a substantially flat plate. As the distance from the center to the peripheral portion increases, the inclination of the normal line of the blade 51 surface to that of the substrate plate surface increases. For this reason, the light rays in the peripheral portion are more greatly bent in the optical axis direction, and those in the vicinity of the center are relatively small. That is, the entire plate has one lens function, and can perform the function corresponding to the magnifying optical system having the positive refractive power shown in the above two embodiments. Since the enlarged virtual image can be visually projected only by inserting the plate, the optical system can be formed without increasing the thickness, and a great effect can be expected in terms of the mounting performance and the degree of freedom of design as described above.

[0046]

As is apparent from the above embodiments, according to the present invention, a compound triangular pyramid prism is used to effectively bend a light beam containing image information from an image display module, thereby making it thinner and more compact. Optics can be realized, and the head portion of the display device can be configured to be small and light, particularly thin. The feeling of wearing and balance on the face is remarkably improved due to the reduction in thickness, and the simplification of the mechanism can be realized for the assist of wearing, and the degree of freedom in design can be increased.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a display device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical system of the display device of FIG. 1;

FIG. 3 is an enlarged view of a main part of the display device of FIG. 1;

FIG. 4 is a configuration diagram of an optical system of a display device according to a second embodiment of the present invention.

FIG. 5 is a configuration diagram of an optical system of a display device according to a third embodiment of the present invention.

FIG. 6 is a configuration diagram of an optical system of a conventional display device.

FIG. 7 is a configuration diagram of a conventional concave mirror reflection type display device.

FIG. 8 is a configuration diagram of the display device of FIG. 7 using a half mirror.

FIG. 9 is a configuration diagram of an eccentric concave mirror type display device.

FIG. 10 is a configuration diagram of the display device of FIG. 9 using a prism.

[Explanation of symbols]

 21a, b Head part 22a, b Display module 23a, b Image magnifying lens 24a, b Composite prism 25a, b Small circuit part 26 Signal cable lead-out part 27 Adjustment mechanism 28 Backlight power supply 29 Backlight device 30 Image processing module 31 Display module 32 Composite prism 33 Incident surface (second internal reflection surface, exit surface) 34 First internal reflection surface 35 Third internal reflection surface 36 Image magnifying lens

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 EA22 HA22 HA23 HA24 HA27 MA07 2H091 FA14X FA15X FB08 LA11 LA19 5C040 GH10 5G435 AA18 BB12 BB15 DD01 DD02 DD03 EE26 FF13 GG01 GG02 GG03 GG05 HH16

Claims (9)

[Claims] 1. An image display means for displaying an image in a liquid crystal or photoelectric manner, an image enlargement means for optically enlarging an image by the image display means for qualification, and the image enlargement means from the image display means. An optical prism means having a function of bending an optical path to the means, wherein the optical prism means faces the display screen of the image display device in a non-contact manner on a substantially flat incident surface, and further displays the image. The optical path incident on the optical prism means from the device is bent at a first internal reflection surface formed of a flat or curved surface inside the optical prism means, and then bent at a second internal reflection surface formed of a substantially flat surface. Alternatively, the optical prism means may be bent at a third internal reflection surface formed of a curved surface, and then pass through an exit surface formed in the same plane as the incident surface. Characterized in that the display device is projected from the device and further enlarged and projected by the image enlarging means. 2. The display apparatus according to claim 1, wherein said image enlarging means is made of a dielectric member having a positive refractive power and disposed in proximity to and out of contact with an exit surface of said optical prism means. 3. The display device according to claim 2, wherein said dielectric member having a positive refractive power comprises a convex lens, an aspheric optical lens, a Fresnel lens, or a hologram lens. 4. A dielectric multilayer film or a semi-permeable film made of a metal film, on which a part of light from the outside of the optical prism means can enter, on the first inner reflection surface of the optical prism means. The display device according to claim 1, wherein the display device is configured. 5. A concave lens for canceling a positive refractive power of said image enlarging means or a negative refractive power of a Fresnel lens on the outside of said first internal reflection surface across said semipermeable membrane. The display according to claim 4, further comprising a refractive power correction prism, and a liquid crystal or a mechanical light shielding unit for arbitrarily shielding light transmitted through the semi-permeable membrane. apparatus. 6. The display device according to claim 1, wherein said second internal reflection surface in said optical prism means is formed in the same plane as said entrance surface and exit surface. 7. An optical axis of the image enlarging means or a center of a line of sight sandwiched between the optical prism means, and two optical prism means are arranged in parallel so that two emission surfaces are substantially in contact with each other. The display device according to claim 1, wherein the visual fields are combined to correspond to one visual field. 8. The display device according to claim 7, wherein said two optical prism means arranged in parallel are integrally formed of optical glass or transparent resin. 9. The image display means is arranged close to the periphery of the optical axis of the image enlargement means, and is provided one for each of the optical prism means. The display device according to claim 1 or 7, wherein: