JP2013037095A - Virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device capable of setting an aspect ratio to a desired state with respect to image light that enters eyes of an observer as a virtual image while satisfying limitations on design.SOLUTION: By extending conversion in an aspect ratio converting optical system, an aspect ratio of a virtual image formed can be converted to an aspect ratio of 16:9 wider than an original aspect ratio of 4:3 of an image region of an image display device. Accordingly, for example, even when a lateral width of an image forming device including the image display device with respect an entire virtual image display device is limited by design and an aspect ratio of the image region cannot be set to a relatively wider aspect ratio, for example 16:9, required for video and becomes an aspect ratio close to that of a square, for example aspect ratio of 4:3, an aspect ratio of image light recognized by eyes of an observer as the virtual image can be adjusted to a desired state, for example the aspect ratio of 16:9, by aspect ratio conversion by means of a cylindrical lens.

Description

  The present invention relates to a virtual image display device such as a head mounted display that is used by being mounted on a head.

  2. Description of the Related Art In recent years, various types of virtual image display devices capable of forming and observing virtual images such as a head-mounted display have been proposed that guide image light from a display element to an observer's pupil using a light guide plate.

  In such a virtual image display device, a see-through optical system has been proposed to superimpose image light and external light (see Patent Documents 1 and 2).

  However, as in the above-mentioned Patent Documents 1 and 2, when the virtual image display device is used by being worn on the head, for example, in the shape of glasses, the arrangement and size of the elements constituting the device Various design limitations occur from a structural or design standpoint. On the other hand, as for the aspect ratio (aspect ratio) of the projected image, in recent years, for example, 16: 9 has increased in the direction in which the eyes of the observer are aligned, that is, in the horizontal direction. However, due to the above design limitations, it is not always easy to meet the demand for displaying images with various aspect ratios typified by this type of horizontally long image.

JP 2006-3879 A JP 2010-224473 A

  The present invention has been made in view of the problems of the background art described above, and provides a virtual image display that can set the aspect ratio to a desired state for image light that enters the observer's eyes as a virtual image while satisfying design limitations. An object is to provide an apparatus.

  In order to solve the above problems, a virtual image display device according to the present invention includes (a) an image display device that forms image light, and (b) a projection optical system that forms a virtual image by image light emitted from the image display device. (C) The light incident part that takes in the image light that has passed through the projection optical system and the image light taken in from the light incident part are guided by total reflection on the first and second total reflection surfaces that extend opposite to each other. A light guide device having a light guide unit and a light emitting unit for extracting image light that has passed through the light guide unit to the outside, and (d) the projection optical system has an aspect ratio of a virtual image in an image area of the image display device Includes toric optical system for adjustment.

  In the virtual image display device, the toric optical system can convert the aspect ratio of the virtual image observed by the observer with reference to the image area of the image display element. Thereby, for example, due to design limitations such as arrangement and size, even if the aspect ratio of the image area of the image display element does not match the aspect ratio (aspect ratio) required for the video, By converting the aspect ratio by the toric optical system, the observer can recognize a virtual image having a desired aspect ratio.

  In a specific aspect of the present invention, the toric optical system converts the aspect ratio of the virtual image so as to increase the ratio in the horizontal direction for the observer with reference to the aspect ratio of the display in the image display device. In this case, by increasing the horizontal ratio for the observer, the image recognized by the observer can be longer in the direction in which the eyes of the observer are arranged, that is, in the horizontal direction.

  In yet another aspect of the present invention, the toric optical system performs at least one of expansion conversion in a first direction corresponding to a lateral direction for the observer and reduction conversion in a second direction perpendicular to the first direction. Do. In this case, the image recognized by the viewer can be made to have a relatively horizontally long desired aspect ratio by expansion conversion in the first direction, reduction conversion in the second direction, or both conversions.

  In still another aspect of the present invention, (a) the image forming apparatus is arranged on the ear side of the observer who observes the image light, and (b) the light guide apparatus is arranged along the horizontal direction for the observer. Lead. In this case, for example, the virtual image display device can be made relatively small like a glasses type.

  In still another aspect of the present invention, in the image display device, the aspect ratio of each shape of the plurality of pixels arranged in the image region is opposite to the conversion ratio by the toric optical system. In this case, even if no special image processing is performed, the viewer can recognize the original image in the state in which the aspect ratio is maintained as it is.

  In still another aspect of the present invention, in the image display device, a plurality of pixels are configured by arranging pixel elements of three segments in a line. In this case, a color image can be formed.

  In still another aspect of the present invention, the three-segment pixel elements are three colors of RGB, and are arranged in a line in the horizontal direction for the observer. In this case, a color image can be formed by forming three segments by three colors of RGB, and by arranging in a row in the horizontal direction, it is more efficient when an active matrix type liquid crystal is adopted in the image display device. Light can be used.

  In still another aspect of the present invention, in the image display device, a plurality of pixels are configured by arranging pixel elements of 4 segments in 2 rows and 2 columns. In this case, the amount of light can be increased and the color reproducibility can be improved by the four-segment color scheme.

  In still another aspect of the present invention, the four-segment pixel elements are composed of three colors of RGB. In this case, by increasing one of the three colors more than the other colors, it is possible to balance the amount of light between the colors or to secure the amount of light necessary for the entire pixel according to the characteristics of the light source. Can do.

  In still another aspect of the present invention, the four-segment pixel elements are configured by four colors obtained by adding other colors to three colors of RGB. In this case, by adding other colors, it becomes possible to increase the amount of light or improve the color reproducibility.

  In still another aspect of the present invention, the virtual image display device is configured to convert the conversion ratio and the inverse ratio for an image signal input from the outside to the image display device in accordance with the conversion ratio of the aspect ratio of the image light by the toric optical system. The image processing unit further performs an aspect ratio conversion process. In this case, the image recognized by the observer can be kept as the original image by the image signal at the time of input from the outside by image processing that compensates the conversion of the aspect ratio by the toric optical system.

  In still another aspect of the present invention, the virtual image display device further includes a drive mechanism that moves the toric optical system on the optical path of the image light. In this case, the drive mechanism can be switched on / off or the like for the conversion of the aspect ratio by the toric optical system.

  In still another aspect of the present invention, the toric optical system has a pair of concave and convex cylindrical lenses arranged in a direction facing a light incident surface of a light guide device that takes in image light therein, and the cylindrical lenses The conversion ratio of the aspect ratio of the image light is adjusted by changing the arrangement of. In this case, the conversion ratio of the aspect ratio of the image light can be appropriately set by changing the arrangement of the one set of concave and convex cylindrical lenses.

  In still another aspect of the present invention, (a) the light guide unit has a first reflection surface and a second reflection surface that are arranged in parallel to each other and enable light guide by total reflection, and (b) light incidence. The portion has a third reflecting surface that makes a predetermined angle with respect to the first reflecting surface, and (c) the light emitting portion has a fourth reflecting surface that makes a predetermined angle with respect to the first reflecting surface. In this case, the image light reflected by the third reflecting surface of the light incident portion is propagated while being totally reflected by the first and second reflecting surfaces of the light guide portion, and is reflected by the fourth reflecting surface of the light emitting portion. Thus, it is possible to form a virtual image for entering the observer's eyes.

  In still another aspect of the present invention, the light guide device includes a hologram element on at least one of the third reflection surface and the fourth reflection surface. In this case, the optical path of image light can be adjusted using a hologram element, and light can be taken in with high efficiency.

  In still another aspect of the present invention, the light guide device has a plurality of reflection surfaces extending in a predetermined direction, and the image light guided by the total reflection at the first and second total reflection surfaces of the light guide unit. An angle conversion unit that bends toward the light emitting unit side by a plurality of reflecting surfaces is further provided. In this case, the angle conversion unit can cause the observer to recognize the image by bending the image light toward the light emitting unit and emitting the light.

It is a perspective view which shows the virtual image display apparatus of embodiment. (A) is a top view of the main-body part of the 1st display apparatus which comprises a virtual image display apparatus, (B) is a front view of a main-body part. (A) is the conceptual diagram which expand | deployed the optical path regarding the vertical 1st direction, (B) is the conceptual diagram which expand | deployed the optical path regarding the horizontal 2nd direction. It is a top view explaining the optical path in the optical system of a virtual image display apparatus concretely. (A) shows the display surface of a liquid crystal display device, (B) is a figure explaining notionally the virtual image of the liquid crystal display device which an observer can see, (C) and (D) comprise a virtual image It is a figure explaining the partial image to do. (A) is sectional drawing which shows the structure of a virtual image display apparatus typically, (B) is a side view, (C) is a perspective view of a set of cylindrical lenses which comprise an aspect ratio conversion optical system. FIG. (A) is a schematic diagram showing a panel image corresponding to a virtual image recognized by an observer, (B) is a diagram of a comparative example, and (C) is an optical path in an aspect ratio conversion optical system. It is a schematic diagram for demonstrating. (A) is a figure which shows the pixel of the panel image which reflects the pixel of the image area | region of an image display element, (B) is a figure which shows the state of the pixel of the panel image in which the aspect ratio was converted. (A) is a figure which shows the state before conversion of the aspect ratio of the RGB pixel arranged in the vertical line, (B) is a figure which shows the state after conversion of an aspect ratio, (C) is It is a figure which shows the state before conversion of the aspect ratio of the RGB pixel arranged in a horizontal row, (D) is a figure which shows the state after conversion of an aspect ratio, (E) is square 4 squares It is a figure which shows the state before conversion of the aspect ratio of the arranged RGB pixel, (F) is a figure which shows the state after conversion of an aspect ratio, (G) is arranged in four square squares It is a figure which shows the state before conversion of the aspect ratio of a 4 color pixel, (H) is a figure which shows the state after conversion of an aspect ratio. (A) is sectional drawing which shows the virtual image display apparatus which concerns on 2nd Embodiment, (B) is a side view. (A) is sectional drawing which shows the virtual image display apparatus which concerns on 3rd Embodiment, (B) is a side view. (A) is a figure explaining the virtual image display apparatus which concerns on 4th Embodiment, (B) is a figure which shows the mode of an image process. (A) is a figure explaining the virtual image display apparatus which concerns on 5th Embodiment, (B) is a figure for demonstrating operation | movement of a virtual image display apparatus, (C) is the state at the time of lens separation. FIG. 4D is a diagram for explaining the optical path in the horizontal direction, FIG. 4D is a diagram for explaining the optical path in the vertical direction, and FIG. 4E is a diagram for explaining the optical path in the lateral direction when the lens is in close contact. (F) is a figure explaining the optical path about the vertical direction. (A) is a figure which shows the state of the pixel after conversion of the aspect ratio at the time of lens separation, (B) is a figure which shows the state of the pixel after conversion of the aspect ratio at the time of lens contact | adherence. It is a flowchart for demonstrating the image process in a virtual image display apparatus. (A) is sectional drawing explaining the modification of the virtual image display apparatus which concerns on 5th Embodiment, (B) is a side view. (A) is sectional drawing which shows the virtual image display apparatus which concerns on 6th Embodiment, (B) is a front view of a light guide member, (C) is a top view of a light guide member. (A) is a schematic diagram for demonstrating the structure of an angle conversion part, and the optical path of the image light in an angle conversion part, (B) is a figure which shows the mode of the reflection in the back | inner side of an angle conversion part. (C) is a figure which shows the mode of reflection in the entrance side of an angle conversion part. (A) is sectional drawing which shows the structure of a virtual image display apparatus, (B) is a side view. It is a figure for demonstrating an example of another virtual image display apparatus. It is a figure for demonstrating an example of another virtual image display apparatus. (A) is a figure which shows the example of a display of the image for demonstrating another virtual image display apparatus, (B) is an example of the image after conversion of an aspect ratio, (C) is an aspect ratio. It is another example of the image after conversion of (D), (D) is a figure of a comparative example.

  Hereinafter, a virtual image display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[A. Appearance of virtual image display device)
A virtual image display device 100 according to the embodiment shown in FIG. 1 is a head-mounted display having an appearance like glasses, and allows an observer wearing the virtual image display device 100 to recognize image light due to a virtual image. It is possible to make the observer observe the external image with see-through. The virtual image display device 100 includes an optical panel 110 that covers the eyes of the observer, a frame 121 that supports the optical panel 110, and hinges (not shown) that extend from both sides of the frame 121 in front of the eyes and fold the frame 121. ) (Front cover) 141, 142 occupying the front side of the first and second drive parts 131, 132 added to the parts (temple) 151, 152 occupying from the rear stage to the part covering the ear from the hinge. Prepare. Here, the optical panel 110 has a first panel portion 111 and a second panel portion 112, and both the panel portions 111 and 112 are plate-like parts integrally connected at the center. The first display device 100A in which the first panel portion 111 on the right side and the first drive unit 131 are combined in the drawing is in the right half range from the center of the entire virtual image display device 100 surrounded by a broken line in the figure, It is a part that forms a virtual image for the right eye, and functions alone as a virtual image display device. Further, the second display device 100B in which the second panel portion 112 on the left side and the second drive unit 132 in the drawing are combined is in the range of the left half from the center of the entire virtual image display device 100, and is a virtual image for the left eye. Even if used alone, it functions as a virtual image display device. In this case, the image forming apparatus 10 is disposed close to the observer's ear.

[B. Display device structure]
As shown in FIG. 2A and the like, the first display device 100A includes an image forming device 10 and a light guide device 20. Here, the image forming apparatus 10 corresponds to the first drive unit 131 within the range surrounded by the broken line in FIG. 1, and the light guide device 20 corresponds to the first panel portion 111 in FIG. Note that the second display device 100B shown in FIG. 1 has the same structure as the first display device 100A and is simply flipped left and right, and thus detailed description of the second display device 100B is omitted.

  The image forming apparatus 10 includes an image display device 11 and a projection optical system 12. Among these, the image display device 11 operates the illumination device 31 that emits the two-dimensional illumination light SL, the liquid crystal display device 32 that is a transmissive spatial light modulation device, and the operations of the illumination device 31 and the liquid crystal display device 32. And a drive control unit 34 for controlling.

  The illumination device 31 includes a light source 31a that generates light including three colors of red, green, and blue, and a backlight light guide unit that diffuses light from the light source 31a into a light beam having a two-dimensional expansion of a rectangular cross section. 31b. The liquid crystal display device 32 spatially modulates the illumination light SL from the illumination device 31 to form image light to be a display target such as a moving image. The drive control unit 34 includes a light source drive circuit 34a and a liquid crystal drive circuit 34b. The light source driving circuit 34a supplies electric power to the light source 31a of the lighting device 31 to emit the illumination light SL having a stable luminance. The liquid crystal driving circuit 34b outputs an image signal or a driving signal to the liquid crystal display device 32, thereby forming color image light that is a source of a moving image or a still image as a transmittance pattern. The liquid crystal driving circuit 34b can have an image processing function, but an external control circuit can also have an image processing function.

  In the liquid crystal display device 32, the first direction D1 is a direction in which a longitudinal section including a first optical axis AX1 passing through the projection optical system 12 and a specific line parallel to a third reflecting surface 21c of the light guide member 21 described later extends. The second direction D2 corresponds to a direction in which a transverse section including the first optical axis AX1 and the normal line of the third reflecting surface 21c extends. That is, at the position of the liquid crystal display device 32, the first direction D1 corresponds to the vertical Y direction, and the second direction D2 corresponds to the horizontal Z direction.

  The projection optical system 12 adjusts the collimating lens 13 that converts the image light emitted from each point on the liquid crystal display device 32 into a parallel light beam, and the spread state of the image light that is converted into a parallel light beam by the collimating lens 13. Thus, the lens group includes the aspect ratio conversion optical system 15 that is a toric optical system that adjusts the aspect ratio of the virtual image to be displayed.

  The light guide device 20 is formed by joining a light guide member 21 and a light transmission member 23, and constitutes a flat plate-like optical member that extends parallel to the YZ plane as a whole.

  In the light guide device 20, the light guide member 21 is a trapezoidal prism-like member in plan view, and includes, as side surfaces, a first reflection surface 21 a, a second reflection surface 21 b, a third reflection surface 21 c, and a fourth reflection surface. A reflective surface 21d. The light guide member 21 includes an upper surface 21e and a lower surface 21f that are adjacent to the first, second, third, and fourth reflecting surfaces 21a, 21b, 21c, and 21d and that face each other. Here, the first and second reflecting surfaces 21 a and 21 b extend along the YZ plane and are separated by a thickness t of the light guide member 21. The third reflecting surface 21c is inclined at an acute angle α of 45 ° or less with respect to the YZ plane, and the fourth reflecting surface 21d is inclined at an acute angle β of 45 ° or less with respect to the XY surface. . The first optical axis AX1 passing through the third reflecting surface 21c and the second optical axis AX2 passing through the fourth reflecting surface 21d are arranged in parallel and separated by a distance D. An end surface 21h is provided between the first reflecting surface 21a and the third reflecting surface 21c so as to remove a ridge. The light guide member 21 has a polyhedral outer shape with seven surfaces including the end surface 21h.

  The light guide member 21 performs light guide using total reflection by the first and second reflection surfaces 21a and 21b, and is a direction that is folded by reflection when light is guided and a direction that is not folded by reflection when light is guided. There is. When an image guided by the light guide member 21 is considered, the lateral direction that propagates while being folded back by a plurality of reflections during light guide, that is, the confinement direction is perpendicular to the first and second reflecting surfaces 21a and 21b (X axis). And parallel to the light source side, and corresponds to the second direction D2 of the liquid crystal display device 32. On the other hand, the longitudinal direction, that is, the non-confined direction that propagates without being folded back by reflection during light guiding is parallel to the first and second reflecting surfaces 21a, 21b and the third reflecting surface 21c (parallel to the Y axis), as will be described later. Corresponds to the first direction D <b> 1 of the liquid crystal display device 32. In the light guide member 21, the main light direction in which the propagated constraint is directed as a whole is the + Z direction.

  The light guide member 21 is formed of a resin material that exhibits high light transmittance in the visible range. The light guide member 21 is a block-like member that is integrally molded by injection molding, and is formed, for example, by injecting a heat or photopolymerization type resin material into a molding die and thermosetting or photocuring. . Thus, although the light guide member 21 is an integrally formed product, it can be functionally divided into the light incident part B1, the light guide part B2, and the light emitting part B3.

  The light incident part B1 is a triangular prism-shaped part, and includes a light incident surface IS that is a part of the first reflective surface 21a and a third reflective surface 21c that faces the light incident surface IS. The light incident surface IS is a flat surface on the back side or the viewer side for taking in the image light GL from the image forming apparatus 10 and extends perpendicularly to the first optical axis AX1 facing the projection optical system 12. The third reflection surface 21c has a rectangular outline, and has a total reflection mirror layer for reflecting and guiding the image light GL that has passed through the light incident surface IS into the light guide B2 over the entire rectangular area. The total reflection mirror layer is formed by forming a film on the inclined surface RS of the light guide member 21 by vapor deposition of aluminum or the like. The third reflecting surface 21c is inclined with respect to the first optical axis AX1 or the XY plane of the projection optical system 12, for example, at an acute angle α = 25 ° to 27 °, and is incident from the light incident surface IS as a whole in the −X direction. The image light GL heading toward the center is bent so as to be directed toward the + Z direction closer to the + X direction as a whole, so that the image light GL is reliably coupled into the light guide B2.

  The light guide part B2 has a first reflecting surface 21a and a second reflecting surface 21b that totally reflect the image light bent by the light incident part B1 as two planes that face each other and extend parallel to the YZ plane. Yes. The distance between the first and second reflecting surfaces 21a and 21b, that is, the thickness t of the light guide member 21 is, for example, about 9 mm. Here, it is assumed that the first reflecting surface 21a is on the back side or the viewer side close to the image forming apparatus 10, and the second reflecting surface 21b is on the front side or the outside side far from the image forming apparatus 10. In this case, the first reflecting surface 21a is a surface portion common to the above-described light incident surface IS and a light emitting surface OS described later. The first and second reflection surfaces 21a and 21b are total reflection surfaces using a difference in refractive index, and the surface thereof is not provided with a reflection coating such as a mirror layer, but the surface is prevented from being damaged and the image is displayed. In order to prevent a decrease in resolution, it is covered with a hard coat layer. The hard coat layer is formed by depositing a coating material containing a resin or the like on the light guide member 21 by dipping or spray coating.

  The image light GL reflected by the third reflecting surface 21c of the light incident part B1 first enters the first reflecting surface 21a and is totally reflected. Next, the image light GL enters the second reflecting surface 21b and is totally reflected. By repeating this operation thereafter, the image light is guided to the leading light direction on the back side of the light guide device 20 as a whole, that is, to the + Z side where the light emitting part B3 is provided. In addition, since the 1st and 2nd reflective surfaces 21a and 21b are not provided with the reflective coating, the external light or the external light incident on the second reflective surface 21b from the external side passes through the light guide B2 with high transmittance. pass. In other words, the light guide B2 is a see-through type that allows the external image to be seen through.

  The light emission part B3 is a triangular prism-shaped part, and has a light emission surface OS that is a part of the first reflection surface 21a and a fourth reflection surface 21d that faces the light emission surface OS. The light emission surface OS is a front surface plane for emitting the image light GL toward the observer's eye EY, and is a part of the first reflection surface 21a, like the light incident surface IS. It extends perpendicular to the optical axis AX2. The distance D between the second optical axis AX2 passing through the light emitting part B3 and the first optical axis AX1 passing through the light incident part B1 is set to, for example, 50 mm in consideration of the width of the observer's head. The fourth reflecting surface 21d is a rectangular flat surface for reflecting the image light GL that has entered through the first and second reflecting surfaces 21a and 21b to be emitted outside the light emitting portion B3. A half mirror layer 28 is attached to the fourth reflecting surface 21d. The half mirror layer 28 is a light-transmissive reflective film (that is, a semi-transmissive reflective film). The half mirror layer (semi-transmissive reflective film) 28 is formed by forming a metal reflective film or a dielectric multilayer film on the inclined surface RS constituting the fourth reflective surface 21 d of the light guide member 21. The reflectance of the half mirror layer 28 with respect to the image light GL is set to 10% to 50% in the assumed incident angle range of the image light GL from the viewpoint of facilitating observation of the external light GL ′ by see-through. The reflectance of the half mirror layer 28 of the specific embodiment with respect to the image light GL is set to 20%, for example, and the transmittance with respect to the image light GL is set to 80%, for example.

  The fourth reflecting surface 21d is inclined at an acute angle α = 25 ° to 27 °, for example, with respect to the second optical axis AX2 or YZ plane perpendicular to the first reflecting surface 21a, and is guided by the half mirror layer 28. The image light GL incident through the first and second reflecting surfaces 21a and 21b of the portion B2 is partially reflected and bent so as to be directed in the + X direction as a whole, thereby allowing the light exit surface OS to pass therethrough. The component of the image light transmitted through the fourth reflecting surface 21d is incident on the light transmitting member 23 and is not used for forming an image.

  The light transmission member 23 has the same refractive index as that of the main body of the light guide member 21, and includes a first surface 23a, a second surface 23b, and a third surface 23c. The first and second surfaces 23a and 23b extend along the YZ plane. The third surface 23c is inclined with respect to the YZ plane, and is disposed in parallel to face the fourth reflecting surface 21d of the light guide member 21. That is, the light transmission member 23 is a member having a wedge-shaped member sandwiched between the second surface 23b and the third surface 23c. Similar to the light guide member 21, the light transmissive member 23 is formed of a resin material exhibiting high light transmittance in the visible region. The light transmitting member 23 is a block-like member that is integrally molded by injection molding, and is formed, for example, by injecting a thermopolymerization resin material into a molding die and thermosetting it.

  In the light transmission member 23, the first surface 23 a is disposed on the extended plane of the first reflecting surface 21 a provided on the light guide member 21, is on the back side close to the observer's eye EY, and the second surface 23 b is guided. It is arranged on the extended plane of the second reflecting surface 21b provided on the optical member 21, and is on the front side far from the observer's eye EY. The third surface 23c is a rectangular light transmission surface joined to the fourth reflection surface 21d of the light guide member 21 by an adhesive. The angle formed by the first surface 23a and the third surface 23c is equal to the angle ε formed by the second reflective surface 21b and the fourth reflective surface 21d of the light guide member 21, and the second surface 23b and the third surface 23c are the same. The angle formed with the surface 23 c is equal to the angle β formed between the first reflecting surface 21 a and the third reflecting surface 21 c of the light guide member 21.

  The light transmission member 23 and the light guide member 21 constitute a see-through portion B4 at the joint portion between them and the vicinity thereof. That is, since the first and second surfaces 23a and 23b are not provided with a reflective coating such as a mirror layer, the external light GL ′ is transmitted with a high transmittance similarly to the light guide part B2 of the light guide member 21. . The third surface 23c can also transmit the external light GL ′ with high transmittance, but since the fourth reflecting surface 21d of the light guide member 21 has the half mirror layer 28, the third surface 23c passes through the third surface 23c. The ambient light GL ′ to be attenuated by, for example, 20% in the half mirror layer 28. That is, the observer observes the image light GL that has been reduced to 20% and the external light GL ′ that has been reduced to 80% through the half mirror layer 28.

[C. Overview of optical path of image light)
FIG. 3A is a view for explaining an optical path in the first direction D1 corresponding to the longitudinal section CS1 of the liquid crystal display device 32. FIG. In the longitudinal section along the first direction D1, that is, the YZ plane (the unfolded X′Y ′ plane), of the image light emitted from the liquid crystal display device 32, the upper end side of the display area 32b indicated by the alternate long and short dash line in FIG. The component emitted from the (+ Y side) is referred to as image light GLa, and the component emitted from the lower end side (−Y side) of the display area 32b indicated by the two-dot chain line in the drawing is referred to as image light GLb.

The upper image light GLa is converted into a parallel light beam by the projection optical system 12 including the aspect ratio conversion optical system 15, and along the developed optical axis AX ′, the light incident part B <b> 1 and the light guide part B <b> 2 of the light guide member 21. , and it passes through the light emission unit B3, a parallel light beam state with respect to the observer's eye EY, incident inclined from above of the angle phi _1. On the other hand, the lower image light GLb is converted into a parallel light flux by the projection optical system 12, and along the developed optical axis AX ′, the light incident part B <b> 1, the light guide part B <b> 2, and the light emission part of the light guide member 21. The light passes through B3 and is incident on the observer's eye EY in a state of parallel light flux with an inclination from below the angle φ ₂ (| φ ₂ | = | φ ₁ |). The above angles φ ₁ and φ ₂ correspond to the upper and lower half angles of view, and are set to, for example, 6.5 °.

  FIG. 3B is a diagram illustrating an optical path in the second direction (confinement direction or synthesis direction) D2 corresponding to the cross section CS2 of the liquid crystal display device 32. Of the image light emitted from the liquid crystal display device 32 in the cross-section CS2 along the second direction D2 (confinement direction or synthesis direction), that is, the XZ plane (the X′Z ′ plane after development), The component emitted from the first display point P1 on the right end side (+ Z side) toward the display region 32b shown is the image light GLc, and the left end side (−Z side) toward the display region 32b shown by the two-dot chain line in the figure. The component emitted from the second display point P2 is image light GLd. In FIG. 3B, for reference, image light GLe emitted from the inner right side and image light GLf emitted from the inner left side are added.

The image light GLc from the first display point P1 on the right side is converted into a parallel light flux by the projection optical system 12, and along the developed optical axis AX ′, the light incident portion B1 and the light guide portion of the light guide member 21. B2, and through the light exit portion B3, a parallel light beam state with respect to the observer's eye EY, incident inclined from right angles theta _1. On the other hand, the image light GLd from the second display point P2 on the left side is converted into a parallel light flux by the projection optical system 12, and along the developed optical axis AX ′, the light incident portion B1 of the light guide member 21, The light passes through the light part B2 and the light emission part B3, and enters the observer's eye EY in a state of parallel light flux, tilted from the left direction at an angle θ ₂ (| θ ₂ | = | θ ₁ |). The above angles θ ₁ and θ ₂ correspond to the left and right half angles of view, and are set to 10 °, for example.

Note that, in the horizontal direction of the second direction D2, the image lights GLc and GLd are folded back by reflection in the light guide member 21 and the number of reflections is different, so that each image light GLc and GLd is in the light guide member 21. It is expressed discontinuously. In addition, regarding the observer's eye EY, the viewing direction is upside down compared to the case of FIG. As a result, the screen is horizontally reversed as a whole in the horizontal direction, but the right half image of the liquid crystal display device 32 and the liquid crystal display device can be obtained by processing the light guide member 21 with high accuracy as will be described in detail later. The images on the left half of 32 are continuously joined without any gap. In consideration of the fact that the number of reflections of the image light GLc and GLd in the light guide member 21 is different from each other, the emission angle θ ₁ ′ of the right image light GLc and the emission angle θ ₂ ′ of the left image light GLd. Is set to something different.

  As described above, the image lights GLa, GLb, GLc, and GLd incident on the observer's eye EY are virtual images from infinity, and the image formed on the liquid crystal display device 32 is correct in the first vertical direction D1. The image formed on the liquid crystal display device 32 is reversed with respect to the second horizontal direction D2.

[D. (The optical path of image light in the horizontal direction)
FIG. 4 is a cross-sectional view illustrating a specific optical path in the second horizontal direction D2 in the first display device 100A. As described above, the projection optical system 12 includes the collimating lens 13 including a plurality of lenses (not shown) and the aspect ratio conversion optical system 15 for converting the aspect ratio of the virtual image in the image area. doing. The aspect ratio conversion optical system 15 includes a pair of cylindrical lenses 15a and 15b. The aspect ratio conversion optical system 15 uses a pair of cylindrical lenses 15a and 15b having optical surfaces having different curvature radii in the vertical direction and the horizontal direction, so that the parallel state of the image light converted into a parallel beam by the collimating lens 13 is used. The angle of incidence can be changed by adjusting the angle of view by changing the angle of incidence on the eye EY of the observer while maintaining the above. Here, as an example, the aspect ratio, that is, the aspect ratio in the image area of the image display device 11 is set to 4: 3, and the ratio is converted so that the aspect ratio is 16: 9 when the observer recognizes this as a virtual image. Is going. Details of the aspect ratio conversion operation by the aspect ratio conversion optical system 15 will be described later.

  The image lights GL11 and GL12 from the first display point P1 on the right side of the liquid crystal display device 32 pass through the collimating lens 13 of the projection optical system 12 to be converted into parallel light fluxes. Further, the image light GL11 and GL12 pass through the aspect ratio conversion optical system 15 of the projection optical system 12, so that the optical path direction is adjusted with respect to the horizontal direction for the aspect ratio conversion while maintaining the parallel light flux state. The In other words, the aspect ratio conversion optical system 15 adjusts the angle of view in the image area of the liquid crystal display device 32 by adjusting the angle of view in the horizontal direction for the projected image.

The image lights GL11 and GL12 that have passed through the projection optical system 12 enter the light incident surface IS of the light guide member 21. The image lights GL11 and GL12 guided into the light guide member 21 repeat total reflection at the same angle on the first and second reflection surfaces 21a and 21b, and are finally emitted as a parallel light flux from the light exit surface OS. . Specifically, the image lights GL11 and GL12 are reflected by the third reflection surface 21c of the light guide member 21 as parallel light beams, and then enter the first reflection surface 21a of the light guide member 21 at the first reflection angle γ1. , Total reflection (first total reflection). Thereafter, the image lights GL11 and GL12 are incident on the second reflecting surface 21b and totally reflected (second total reflection) while maintaining the first reflection angle γ1, and then incident on the first reflecting surface 21a again. And is totally reflected (third total reflection). As a result, the image lights GL11 and GL12 are totally reflected three times on the first and second reflecting surfaces 21a and 21b, and enter the fourth reflecting surface 21d. The image lights GL11 and GL12 are reflected by the fourth reflection surface 21d at the same angle as the third reflection surface 21c, and are angled from the light emission surface OS to the second optical axis AX2 direction perpendicular to the light emission surface OS. It is emitted as a parallel light beam by theta ₁ slope.

The image lights GL21 and GL22 from the second display point P2 on the left side of the liquid crystal display device 32 are converted into parallel beams by passing through the collimating lens 13 of the projection optical system 12, and are parallel beams when passing through the aspect ratio converting optical system 15. The optical path is adjusted while maintaining the converted state, and enters the light incident surface IS of the light guide member 21. The image lights GL21 and GL22 guided into the light guide member 21 repeat total reflection at equal angles on the first and second reflection surfaces 21a and 21b, and are finally emitted from the light exit surface OS as parallel light beams. . Specifically, the image lights GL21 and GL22 are reflected by the third reflecting surface 21c of the light guide member 21 as a parallel light beam, and then the first reflection of the light guide member 21 at the second reflection angle γ2 (γ2 <γ1). The light enters the surface 21a and is totally reflected (first total reflection). Thereafter, the image lights GL21 and GL22 enter the second reflection surface 21b and are totally reflected (second total reflection) while maintaining the second reflection angle γ2, and then enter the first reflection surface 21a again. Are totally reflected (third total reflection), are incident again on the second reflecting surface 21b and totally reflected (fourth total reflection), and are again incident on the first reflecting surface 21a and totally reflected. (5th total reflection). As a result, the image lights GL21 and GL22 are totally reflected five times on the first and second reflecting surfaces 21a and 21b and enter the fourth reflecting surface 21d. The image lights GL21 and GL22 are reflected by the fourth reflecting surface 21d at the same angle as the third reflecting surface 21c, and are angled from the light emitting surface OS to the second optical axis AX2 direction perpendicular to the light emitting surface OS. It is emitted as a parallel light beam by theta ₂ gradient.

  In FIG. 4, when the light guide member 21 is developed, a virtual first surface 121a corresponding to the first reflection surface 21a, and when the light guide member 21 is deployed, a virtual first surface 121b corresponding to the second reflection surface 21b. The 2nd surface 121b is drawn. By developing in this way, the image lights GL11 and GL12 from the first display point P1 pass through the first surface 121a twice after passing through the incident equivalent surface IS ′ corresponding to the light incident surface IS. It can be seen that the light passes through the surface 121b once, is emitted from the light exit surface OS, and enters the observer's eye EY, and the image lights GL21 and GL22 from the second display point P2 are incident corresponding to the light entrance surface IS. After passing through the equivalent surface IS ″, it can be seen that it passes through the first surface 121a three times, passes through the second surface 121b twice, is emitted from the light exit surface OS, and enters the observer's eye EY. In other words, the observer observes the lens 15b of the projection optical system 12 existing in the vicinity of the incident equivalent surfaces IS ′ and IS ″ at two different positions.

  FIG. 5A is a diagram for conceptually explaining the display surface of the liquid crystal display device 32, and FIG. 5B is a diagram for conceptually explaining a virtual image of the liquid crystal display device 32 that can be seen by an observer. FIGS. 5C and 5D are diagrams illustrating partial images constituting a virtual image. A rectangular image forming area AD provided in the liquid crystal display device 32 shown in FIG. 5A is observed as a virtual image display area AI shown in FIG. On the left side of the virtual image display area AI, a first projection image IM1 corresponding to a portion from the center to the right side of the image forming area AD of the liquid crystal display device 32 is formed. This first projection image IM1 is shown in FIG. ) As shown in FIG. Further, on the right side of the virtual image display area AI, a projection image IM2 corresponding to a portion from the center to the left side of the image formation area AD of the liquid crystal display device 32 is formed as a virtual image. This second projection image IM2 is shown in FIG. As shown in (D), the left half is a partial image.

  The first partial region A10 that forms only the first projection image (virtual image) IM1 in the liquid crystal display device 32 illustrated in FIG. 5A includes the first display point P1 at the right end of the liquid crystal display device 32, for example. The image lights GL11 and GL12 that are totally reflected three times in total in the light guide portion B2 of the light guide member 21 are emitted. The second partial area A20 that forms only the second projection image (virtual image) IM2 in the liquid crystal display device 32 includes, for example, the second display point P2 at the left end of the liquid crystal display device 32, and the light guide member 21 guides the light. The image light GL21 and GL22 that are totally reflected five times in the portion B2 are emitted. The image light from the band SA extending vertically and sandwiched between the first and second partial areas A10 and A20 near the center of the image forming area AD of the liquid crystal display device 32 forms an overlapping image SI shown in FIG. doing. That is, the image light from the band SA of the liquid crystal display device 32 is a total of 5 in the first projection image IM1 formed by the image light GL11 and GL12 totally reflected three times in the light guide B2, and in the light guide B2. The second projected image IM2 formed by the image lights GL11 and GL12 that are totally reflected once is superimposed on the virtual image display area AI. If the light guide member 21 is precisely processed and a light beam accurately collimated by the projection optical system 12 is formed, the overlapping image SI is prevented from being displaced or blurred due to the superimposition of the two projection images IM1 and IM2. be able to.

  In the above, the total number of reflections of the image light GL11 and GL12 emitted from the first partial area A10 including the first display point P1 on the right side of the liquid crystal display device 32 by the first and second reflecting surfaces 21a and 21b is three times in total. Thus, the total number of reflections of the image light GL21 and GL22 emitted from the second partial area A20 including the second display point P2 on the left side of the liquid crystal display device 32 by the first and second reflecting surfaces 21a and 21b is five times in total. However, the total number of reflections can be changed as appropriate. That is, by adjusting the outer shape (that is, thickness t, distance D, acute angles α, β) of the light guide member 21, the total number of reflections of the image light GL11, GL12 is set to five times, and the total reflection number of the image light GL21, GL22 is A total of seven times can be used. In the above description, the total number of reflections of the image lights GL11, GL12, GL21, and GL22 is an odd number. However, if the light incident surface IS and the light exit surface OS are arranged on the opposite side, that is, the light guide member 21. Is a parallelogram type in plan view, the total number of reflections of the image lights GL11, GL12, GL21, and GL22 is an even number.

  Here, referring back to FIG. 4, the adjustment of the optical paths of the image light GL11, GL12, GL21, and GL22 by the aspect ratio conversion optical system 15 of the projection optical system 12 will be described. In the image formation as described above, the aspect ratio conversion optical system 15 adjusts the optical path so that the optical path of the image light GL11, GL12, GL21, and GL22 has a wider angle than a normal case. The aspect ratio is converted. Specifically, as indicated by a broken line in the figure, if the aspect ratio conversion optical system 15 is not provided, the virtual optical path GLM becomes the optical path of the image light. This virtual optical path GLM is incident on the light guide member 21 and the like at an angle narrower than the optical path of the actual image light GL11, GL12, GL21, GL22. In this case, the state in the image region of the image display device 11 Thus, an image with an aspect ratio of 4: 3 is formed. On the other hand, in the present embodiment, the optical path of the image light is adjusted by the aspect ratio conversion optical system 15. Thereby, on the image display apparatus 11 side, even if the image area has an aspect ratio of 4: 3, the observer can recognize it as a video having a more horizontally long aspect ratio of 16: 9. The aspect ratio conversion optical system 15 is positioned behind the collimating lens 13 in the projection optical system 12 so as to convert the aspect ratio as described above with respect to the image light in the state of being converted into a parallel light flux. It is designed to stretch in the lateral direction. For this reason, it is possible to maintain the state in which the component of the image light is converted into a parallel light beam when passing through the aspect ratio converting optical system 15.

[D. (Aspect ratio conversion optical system structure and aspect ratio conversion by this)
Hereinafter, the structure and function of the aspect ratio conversion optical system 15 will be described in more detail with reference to FIGS. 6 (A) to 6 (C) and 7 (A) to 7 (C). 6A and 6B, other mechanisms, optical paths, and the like are schematically shown in order to give priority to the description of the aspect ratio conversion optical system 15. Here, as conceptually illustrated in FIG. 7A, the aspect ratio conversion optical system 15 shown in FIG. 6A and the like performs angle conversion of the light beam only in the horizontal direction, thereby allowing the observer to The panel image PP corresponding to the recognized image is converted from the original aspect ratio of 4: 3 to the aspect ratio of 16: 9. As conceptually shown in FIG. 7B as a comparative example, if the aspect ratio conversion optical system 15 is not arranged, the aspect ratio conversion as described above is not performed, and the panel image PP is the original image. The aspect ratio of the screen of the display device 11 remains 4: 3.

  6A is a cross-sectional view of the virtual image display device 100 viewed from the Y direction, FIG. 6B is a side view of the virtual image display device 100 viewed from the Z direction, and FIG. 2 is a perspective view of a pair of cylindrical lenses 15a and 15b constituting the aspect ratio converting optical system 15. FIG. In the illustrated virtual image display device 100, the first direction D1, which is the horizontal direction of the image display device 11, corresponds to the horizontal direction of the observer, that is, the horizontal direction E1 of the panel image PP, as shown in FIG. . A second direction D2 that is the vertical direction of the image display device 11 perpendicular to the first direction D1 corresponds to the vertical direction E2 of the panel image PP.

  The aspect ratio converting optical system 15 includes a convex cylindrical lens 15a disposed on the upstream side of the optical path, that is, on the light source side, and a concave cylindrical lens 15b disposed on the downstream side of the optical path, that is, on the opposite light source side. The convex cylindrical lens 15a and the concave cylindrical lens 15b are both arranged so that the generatrix extends in the Y direction, and have a circular arc shape that gives positive and negative refractive powers in a cross section parallel to the XZ plane, and parallel to the XY plane. The cylindrical optical system has an overall appearance as shown in a perspective view in FIG. Each cylindrical lens 15a, 15b is disposed so as to face the light incident surface IS of the light guide member 21 directly or indirectly. Since each cylindrical lens 15a, 15b has the shape and arrangement as described above, the divergence / convergence effect of light passing through, that is, the direction in which expansion / reduction effect on the image light occurs due to the difference in cross-sectional shape. There are orientations that do not or rarely occur. In the case of the cylindrical lenses 15a and 15b illustrated in FIG. 6A and the like, the surfaces HSa and HSb on the downstream side of the optical path are curved surfaces, and the surfaces TSa and TSb on the upstream side of the optical path are flat surfaces.

  As shown in FIGS. 6A and 6B, the image light incident on the aspect ratio converting optical system 15 is collimated in advance by the collimating lens 13. The aspect ratio conversion optical system 15 is an afocal system that converts in an XZ section corresponding to the first direction D1 so as to widen the angle of view while maintaining the parallelism of the light beams of each image light, that is, an optical system having an infinite focal length. And exits while maintaining the parallelism of the incident parallel light flux. On the other hand, the aspect ratio conversion optical system 15 is a non-acting optical system that maintains the angle of view while maintaining the parallelism of the light beams of the respective image lights in the XY cross section corresponding to the second direction D2. Accordingly, in FIG. 6A, that is, in the XZ plane, the image light GL1 and the like are incident as a parallel light flux and emitted as a parallel light flux although the emission angle changes. In FIG. 6B, that is, in the XY plane, the image light GL1 and the like enter as a parallel light flux and are emitted as a substantially parallel light flux. Here, the expansion / reduction in the first direction D1 of the light beam cross section of the image light by the aspect ratio conversion optical system 15, that is, the horizontal direction corresponds to increase / decrease of the emission angle, and constitutes the aspect ratio conversion optical system 15. It is determined by the refractive power and the distance between the cylindrical lenses 15a and 15b. In the case of the arrangement of the lenses 15a and 15b shown in FIG. 6A and the like, the horizontal view angle φ = 2θ is expanded in the Z direction as compared with the case where the lenses 15a and 15b, that is, the aspect ratio conversion optical system 15 are not provided, and the image light. Stretch. On the other hand, the second direction D2, that is, the vertical direction, is neither expanded nor contracted.

Hereinafter, the optical path adjustment of the image light in the first direction D1, that is, the lateral direction on the image forming apparatus 10 side will be described with reference to FIG. Here, in order to describe the aspect ratio conversion by adjusting the optical path in the aspect ratio conversion optical system 15, the image light from the peripheral side of the image display device 11 like the image lights GL2 and GL3 shown in FIG. Consider a component that is emitted by being inclined by an incident angle θ ₀ and intersects the optical axis XX. First, when such a component is incident on the convex cylindrical lens 15a, the incident angle θ having a larger inclination than the incident angle θ _{0 with} respect to the optical axis XX is caused by the convex cylindrical lens 15a and the concave cylindrical lens 15b which are afocal systems. Injected from + Z side or -Z side. The emission angle θ is equal to the value of the horizontal half angle of view θ of the virtual image shown in FIG. As described above, as a result of passing through the aspect ratio conversion optical system 15 and the emission angle θ being larger than the incident angle θ ₀ in the horizontal direction, that is, the angular magnification is increased, the angle of view when the image light is emitted is More spread out. That is, the virtual image by the image light is expanded in the horizontal direction as compared with the case where the aspect ratio conversion optical system 15 is not provided.

In the above, by appropriately determining the positional relationship between the convex cylindrical lens 15a and the concave cylindrical lens 15b and the ratio of their focal lengths, the magnitude of the exit angle θ with respect to the incident angle θ ₀ is set to a desired value. The aspect ratio of the virtual image to be recognized by the observer can be adjusted to a desired ratio. In this case, as an example, the expansion conversion is 4/3 times in the horizontal direction.

Hereinafter, returning to FIG. 6B, the optical path of the image light in the second direction D2, that is, the vertical direction on the image forming apparatus 10 side will be described. In this case, each of the cylindrical lenses 15a and 15b does not have a refractive power and is equivalent to a parallel plate. Therefore, among the image light, for example, the image light GLY emitted from the −Y side of the image display device 11 is used. In addition, neither the component emitted from the peripheral side nor the component on the center side is almost affected by the angle change by the aspect ratio conversion optical system 15. That is, the image light is emitted as it is without being expanded and contracted as compared with the case where the incident angle θ ₀ is set as the emission angle θ _{0 as} it is and the aspect ratio conversion optical system 15 is not provided. Form.

  As a result of the above, the aspect ratio conversion optical system 15 expands in the horizontal direction and hardly changes in the vertical direction, as compared with the case where the aspect ratio conversion optical system 15 is not provided, for the virtual image by the passing image light. It has been converted. That is, conversion is performed at a different ratio between the horizontal direction and the vertical direction. In this case, as described above, the expansion amount in the horizontal direction is set to 4/3 times, so that the conversion from the aspect ratio of 4: 3 to 16: 9 is performed only by the horizontal expansion. By the conversion as described above, image light capable of forming a virtual image having an aspect ratio of 16: 9 can be incident on the light incident surface IS of the light guide member 21. As shown in FIG. 6A, when the virtual image is expanded in the horizontal direction by widening the angle of view, the width of each parallel light beam passing through the light guide member 21 becomes narrow. On the other hand, as shown in FIG. 6B, when neither expansion nor reduction is performed, the width of each parallel light beam passing through the light guide member 21 does not change.

  Hereinafter, the shape of the pixels constituting the image corresponding to the aspect ratio conversion will be described. First, FIG. 8A schematically shows a panel image PP in a state where there is no effect by aspect ratio conversion, corresponding to the screen of the image display device 11. In this case, the shape of the panel image PP is a rectangular shape with an aspect ratio of 4: 3 that directly reflects the shape of the image area PD of the image display device 11. Therefore, the large number of pixels PE arranged in a matrix on the panel image PP can be regarded as indicating the arrangement and shape of the pixels in the image area PD in the image display device 11. On the other hand, FIG. 8B schematically shows the panel image PP in a state where the aspect ratio is converted to 16: 9 by the action of the aspect ratio conversion of the aspect ratio conversion optical system 15. In FIG. 8B, each video pixel PE ′ of the panel image PP has a one-to-one correspondence with each pixel PE in FIG. Here, as described above, the aspect ratio conversion by the aspect ratio conversion optical system 15 is set to be 4/3 times in the horizontal direction. Corresponding to this, each shape of the pixel PE of the panel image PP in FIG. 8A is a vertically long rectangular shape having an aspect ratio opposite to the conversion ratio by the aspect ratio conversion optical system 15. That is, the aspect ratio m: n of each pixel PE is long in the vertical direction, that is, the Y direction, and m: n = 3: 4. Accordingly, each shape of each video pixel PE ′ of the panel image PP shown in FIG. 8B is expanded and converted by the aspect ratio conversion optical system 15 at a conversion ratio of 4/3 times in the horizontal direction, thereby the aspect ratio. It is recognized by the observer as being in a 1: 1 square state. As described above, the shape of the pixel of the image display device 11, that is, the shape of the pixel PE is set in advance in advance corresponding to the aspect ratio conversion in the aspect ratio conversion optical system 15, so that the aspect ratio is converted and the observer is converted. The video that reaches the eye EY is the original video in its natural form without any image processing or the like.

  Hereinafter, pixel elements in the case where each pixel PE is composed of three segments will be described. For example, as shown in FIGS. 9 (A) and 9 (B), a set of vertically arranged pixel elements R1, G1, and B1 of RGB (red, green, and blue) colors arranged in a horizontal row as one set. The pixel PE may be formed. In this case, in each pixel PE ′ after the aspect ratio conversion, each pixel element R1 ′, G1 ′, B1 ′ is expanded in the horizontal direction. Therefore, the pixel elements R1, G1, and B1 before conversion are made to be vertically long in advance, so that the pixel elements R1 ′, G1 ′, and B1 ′ after conversion can have the best shape. Further, as shown in FIGS. 9C and 9D, pixel elements R1, G1, and B1 of three colors RGB (red, green, and blue) can be arranged in a vertical row. In addition to the vertical or horizontal stripe arrangement as described above, for example, an arrangement method such as a delta arrangement or a mosaic arrangement can also be applied. For example, a vertical line can be easily seen or suitable for graphic display by each arrangement method. A suitable one can be selected from various arrangement methods according to the required characteristics.

  In addition to this, for example, as shown in FIGS. 9E and 9F, three pixel elements of RGB (red, green, blue) are arranged in four rectangular squares to obtain one The pixel PE can also be configured. 9 (E) and 9 (F), as an example, R and B are arranged one by one and G is two, that is, pixel elements R1, G1, G2, and B1 are arranged in two rows and two columns, These are converted into pixel elements R1 ′, G1 ′, G2 ′, B1 ′ to form a square pixel PE ′ (see FIG. 9F). Further, as shown in FIGS. 9G and 9H, for example, four-segment pixel elements R1, G1, B1, and Y1 of four colors obtained by adding Y (yellow) to RGB (red, green, and blue). One pixel PE is formed, and each of the arranged pixel elements R1, G1, B1, Y1 is converted into pixel elements R1 ′, G1 ′, B1 ′, Y1 ′ by aspect ratio conversion to form a square pixel PE ′. It is good also as what to do (refer FIG.9 (H)). In the case of four segments, it is possible to increase the amount of light and further improve the color reproducibility by increasing green or adding yellow as described above. Further, the fourth color is not limited to Y (yellow), but may be W (white), for example.

  As described above, the virtual image display device 100 according to the present embodiment has the aspect ratio of the image region PD of the original image display device 11 with respect to the aspect ratio of the virtual image formed by the expansion conversion in the aspect ratio conversion optical system 15. The aspect ratio (16: 9) can be converted to a longer aspect ratio than (4: 3). Accordingly, for example, the width WD of the image forming apparatus 10 including the image display apparatus 11 with respect to the entire virtual image display apparatus 100 is limited by design, and a relatively long aspect ratio (for example, 16: 9) required for the image region PD as an image. Even if the ratio is close to a square (for example, an aspect ratio of 4: 3), the aspect ratio of the image light recognized as a virtual image by the observer's eyes is changed by the cylindrical lenses 15a and 15b. Can be adjusted to a desired state (for example, an aspect ratio of 16: 9).

  In the aspect ratio conversion optical system 15 and the like of the embodiment and each modification, the aspect ratio of the display image on the image display device 11 side is 4: 3, and the aspect ratio of the virtual image by the image light recognized by the observer is Although the conversion is performed so that the ratio is 16: 9, the aspect ratio is not limited to this, and various types are assumed before and after the conversion. The conversion ratio of the aspect ratio can be adjusted, for example, by changing the arrangement of a pair of concave and convex cylindrical lenses 15a and 15b constituting the aspect ratio conversion optical system 15.

  In the virtual image display device 100 of the embodiment described above, the image light GL reflected by the third reflecting surface 21c of the light incident part B1 is totally reflected by the first and second reflecting surfaces 21a and 21b of the light guide part. And is reflected by the fourth reflecting surface 21d of the light emitting part B3 and enters the observer's eye EY as a virtual image. At this time, the number of reflections of the first image light GL11 and GL12 emitted from the first display point P1 of the image display device 11 at the light guide and the second image emitted from the second display point P2 of the image display device 11 are described. Since the number of reflections of the light GL21 and GL22 in the light guide B2 is different, the angle width of the emission angle of the image light GL emitted from the light emission part B3 can be widened. That is, the image light GL from the different partial areas A10 and A20 in the image display device 11 can be taken in with a relatively wide viewing angle, and a large display size of the virtual image observed through the light emitting part B3 is ensured. be able to. In this way, by adopting a structure that takes out the image light GL with different number of reflections, the light emission part B3 can be enlarged so as to cover the pupil without making the light guide part B2 too thick, so the light emission part B3 It is no longer necessary to divide the pupil close to the pupil, a large eye ring diameter can be secured, and good see-through observation is also possible.

[Second Embodiment]
Hereinafter, the virtual image display apparatus according to the second embodiment will be described with reference to FIG. The virtual image display device 200 according to the present embodiment is a modification of the virtual image display device 100 of the first embodiment, and the same reference numerals as those of the virtual image display device 100 of the first embodiment are the same unless otherwise specified. It shall have the function of

  10A is a cross-sectional view of the virtual image display device 200 as viewed from the Y direction, and FIG. 10B is a side view of the virtual image display device 200 as viewed from the Z direction. The virtual image display apparatus 200 according to the present embodiment performs a reduction conversion in a second direction D2 (Y direction) perpendicular to the first direction D1 (Z direction) in the aspect ratio conversion optical system 215, so that a virtual image to be observed. Is converted into the desired aspect ratio. Here, as an example, the aspect ratio of the display image on the image display device 11, that is, the aspect ratio is set to 4: 3, and the image with the aspect ratio of 16: 9 is converted by the reduction conversion that is the aspect ratio conversion by the aspect ratio conversion optical system 215. It shall be recognized by the observer.

  The aspect ratio conversion optical system 215 arranges the concave cylindrical lens 215a on the upstream side of the optical path, that is, the light source side, and arranges the convex cylindrical lens 215b on the downstream side of the optical path, that is, on the opposite light source side, in order to perform reduction conversion in the second direction D2, that is, the vertical direction. It is arranged. More specifically, each of the cylindrical lenses 215a and 215b is arranged so that the generatrix extends in the Z direction, and has a linear shape that gives no refractive power to a cross section parallel to the XZ plane. The cross section parallel to the surface is a cylindrical optical system having an arc shape that gives positive and negative refractive powers. As a result, the aspect ratio conversion optical system 215 is equivalent to a parallel plate with respect to the XZ plane and hardly changes the luminous flux. On the other hand, with respect to the XY plane, while maintaining the parallelism of the luminous flux of the image light, It functions as an afocal system that converts to narrow the corners.

  From the above, first, as shown in FIG. 10A, the optical path of the image light in the first direction D1, that is, the Z direction is hardly affected by the angle change by the aspect ratio conversion optical system 215. That is, the image light is emitted while maintaining its state without being expanded or contracted, as compared with the case where the aspect ratio conversion optical system 215 is not provided.

  On the other hand, as shown in FIG. 10 (B), the optical path of the image light in the second direction D2, that is, the Y direction is set to have an angle of view at the time of emission larger than that at the time of incidence by the aspect ratio conversion optical system 215 that is an afocal system. It changes to narrow. That is, the virtual image by the image light is reduced in the vertical direction as compared with the case where the aspect ratio conversion optical system 215 is not provided.

  As a result, the aspect ratio conversion optical system 215 performs the vertical reduction conversion so that the light beam cross-sectional shape of the entire image light passing therethrough is hardly changed in the horizontal direction and is reduced in the vertical direction. Thus, by converting at a different ratio between the horizontal direction and the vertical direction, for example, conversion from an aspect ratio of 4: 3 to 16: 9 can be performed. In this case, in order to achieve the above-described conversion, the reduction conversion is set to a reduction amount of 3/4 times in the vertical direction.

[Third Embodiment]
Hereinafter, the virtual image display apparatus according to the third embodiment will be described with reference to FIG. The virtual image display device 300 according to the present embodiment is a modification of the virtual image display device 100 of the first embodiment, and the same reference numerals as those of the virtual image display device 100 of the first embodiment are the same unless otherwise specified. It shall have the function of

  In the aspect ratio conversion optical system 315, the virtual image display device 300 performs extension conversion on the first direction D1 (Z direction) corresponding to the horizontal direction for the observer, and the second direction D2 (Y direction perpendicular to the first direction D1). Both the conversion with the reduction conversion with respect to) is performed as the aspect ratio conversion.

  The aspect ratio conversion optical system 315 performs extension conversion in the first direction D1, that is, the horizontal direction, and performs reduction conversion in the second direction D2, that is, the vertical direction. 315a and 315b are arranged. In other words, each toric lens 315a, 315b has an arc shape for both the cross section parallel to the XZ plane and the cross section parallel to the XY plane, but the toric shape differs depending on the cross sectional direction. It has become.

  First, as shown in FIG. 11 (A), the optical path of the image light in the first direction D1, that is, the Z direction is set so that the angle of view at the time of emission is larger than that at the time of incidence by the aspect ratio conversion optical system 315 that is an afocal system. It changes to spread. That is, the virtual image by the image light is expanded in the horizontal direction as compared with the case where the aspect ratio conversion optical system 315 is not provided.

  On the other hand, as shown in FIG. 11B, the optical path of the image light in the second direction D2, that is, the Y direction is set so that the angle of view at the time of emission is larger than that at the time of incidence by the aspect ratio conversion optical system 315 that is an afocal system. It changes to narrow. That is, the virtual image by the image light is reduced in the vertical direction as compared with the case where the aspect ratio conversion optical system 315 is not provided.

  As a result, for the aspect ratio conversion optical system 315, the horizontal expansion amount and the vertical reduction amount are appropriately adjusted, and conversion is performed at different ratios in the horizontal direction and the vertical direction, for example, from an aspect ratio of 4: 3 to 16: 9. Conversion to can be done. In this case, since the amount of change can be made relatively small by appropriately distributing the horizontal expansion amount and the vertical reduction amount, the aspect ratio converting optical system 315 can be more easily manufactured.

[Fourth Embodiment]
Hereinafter, the virtual image display device according to the fourth embodiment will be described with reference to FIG. The virtual image display device 400 according to the present embodiment is a modification of the virtual image display device 100 of the first embodiment, and the same reference numerals as those of the virtual image display device 100 of the first embodiment are the same unless otherwise described. It shall have the function of

  As shown in FIG. 12A, the virtual image display device 400 includes an image processing unit 430 in addition to the image forming device 10 and the light guide device 20.

  The image processing unit 430 performs image processing on an image signal input to the image display device 11 from the outside. Specifically, the image processing unit 430 performs necessary signal processing of the image signal and, as shown in FIG. 12B, displays an original video PP1 corresponding to an image signal input from the outside as an image display device. The horizontal magnification conversion process is performed so that the panel input video PP2 conforms to the shape of the eleven image regions. At this time, the conversion process is performed so that the display image PP3, which is the final image recognized by the observer, returns to the state of the original image PP1. Specifically, for example, the aspect ratio of the original video PP1 is 16: 9, the aspect ratio of the panel input video PP2, that is, the aspect ratio of the image area of the image display device 11, is 4: 3, and the display video PP3 is 16 : 9 Further, it is assumed that the aspect ratio conversion optical system 15 is set to expansion conversion with an expansion amount that is 4/3 times in the horizontal direction. In this case, the image processing unit 430 converts the original video PP1 so as to be reduced to 3/4 times in the horizontal direction, that is, the longitudinal direction L1, in accordance with the conversion ratio in the aspect ratio conversion optical system 15. As a result, as shown in the figure, the video in the panel input video PP2 becomes relatively long because it contracts in the longitudinal direction L1 compared to the original video PP1, but in the display video PP3 which is the final image, the aspect ratio conversion is performed. Therefore, the original image PP1 is restored.

  As described above, in the case of the present embodiment, the image processing unit 430 performs an image processing from the outside in order to compensate for the conversion ratio of the aspect ratio of the image light by the aspect ratio conversion optical system 15 by image processing. An aspect ratio conversion process is performed on the image signal so that the ratio is opposite to the conversion ratio. As a result, the video PP3 recognized by the observer can be left as it is without being expanded or contracted vertically or horizontally with respect to the original video PP1 by the video signal at the time of external input.

[Fifth Embodiment]
Hereinafter, the virtual image display device according to the fifth embodiment will be described with reference to FIG. Note that the virtual image display device 500 according to the present embodiment is a modification of the virtual image display device 100 and the like of the first embodiment, and those having the same reference numerals as the virtual image display device 100 and the like of the first embodiment are not particularly described. As long as it has the same function.

  As illustrated in FIGS. 13A and 13B, the virtual image display device 500 includes an image processing unit 530 and a drive mechanism 540 in addition to the image forming device 510 and the light guide member 21.

  In the image forming apparatus 510, the aspect ratio conversion optical system 515 includes a collimating lens 13 and an aspect ratio conversion optical system 515, and the aspect ratio conversion optical system 515 includes a convex cylindrical lens 515a and a concave cylindrical lens 515b. Composed. Regarding the convex cylindrical lens 515a on the upstream side of the optical path, the surface HSa on the downstream side of the optical path is a cylindrical surface, and the surface TSa on the upstream side of the optical path is a flat surface. On the other hand, for the concave cylindrical lens 515b on the downstream side of the optical path, the surface TSb on the upstream side of the optical path is a cylindrical surface, and the surface HSb on the downstream side of the optical path is a flat surface. Furthermore, the surface HSa and the surface TSb have a pair of corresponding shapes. As shown in FIG. 13B, when the convex cylindrical lens 515a and the concave cylindrical lens 515b are joined, they are in close contact with each other with almost no gap. It has become a thing. As a result, the virtual image display device 500 can be switched between an ON pattern in which aspect ratio conversion is performed and an OFF pattern in which aspect ratio conversion is not performed.

  The drive mechanism 540 supports the cylindrical lenses 515a and 515b constituting the aspect ratio conversion optical system 515, and allows them to slide in the X direction, which is the direction along the optical axis XX. That is, as shown in FIGS. 13A to 13F, the drive mechanism 540 causes the cylindrical lenses 515a and 515b to be separated from each other by a predetermined distance or closely contact each other. That is, the driving mechanism 540 allows the cylindrical lens 515a to reciprocate between the first position PT1 shown in FIG. 13A and the second position PT2 shown in FIG. 13B, and the cylindrical lens 515b. Is capable of reciprocating between the first position PS1 and the second position PS2 in conjunction with the cylindrical lens 515a. The image processing unit 530 performs image processing on an image signal input to the image display device 11 from the outside. At this time, the image processing unit 530 should perform the image processing based on the positional information of the cylindrical lenses 515a and 515b obtained from the drive mechanism 540. Image processing is set. Here, the image processing in the case of performing the aspect ratio conversion by the aspect ratio conversion optical system 515 in the separated state of FIG. 13A is the normal on-pattern image processing, and the close contact of FIG. The image processing when the aspect ratio conversion optical system 515 does not perform the aspect ratio conversion in this state is treated as an image processing of a non-normal off pattern.

  Hereinafter, the aspect ratio conversion operation in the virtual image display device 500 will be described. First, as shown in FIG. 13A, when the cylindrical lenses 515a and 515b are at the first positions PT1 and PS1 and are separated from each other, the cylindrical lenses 515a and 515b have an aspect ratio. Perform conversion. Specifically, as shown in FIG. 13C, both lenses 515a and 515b have a refractive power and are separated from each other with respect to the cross section parallel to the XZ plane. Functions as a focal system. In this case, by arranging a convex lens on the upstream side of the optical path and a concave lens on the downstream side of the optical path, the image light GL2 from the peripheral side can be expanded in the lateral direction by widening the angle. . On the other hand, as shown in FIG. 13D, for the cross section parallel to the XY plane, for example, the image light GLY from the peripheral side is not subjected to angle conversion and is not expanded or contracted by the aspect ratio conversion optical system 515. It is injected while maintaining the state.

  Next, as shown in FIG. 13B, when the cylindrical lenses 515a and 515b are respectively in the second positions PT2 and PS2 and are in close contact with each other, FIGS. As shown in F), the cylindrical lenses 515a and 515b are the same as one integrated parallel plate. In this case, the aspect ratio conversion optical system 515 does not perform ratio conversion both in the horizontal direction and in the vertical direction. That is, the aspect ratio in the image display device 11 is maintained as it is and is recognized by the observer.

  As described above, by the drive mechanism 540, the cylindrical lenses 515a and 515b constituting the aspect ratio conversion optical system 515 are moved on the optical path of the image light and the positions thereof are switched, whereby the conversion by the aspect ratio conversion optical system 515 is performed. The ratio can be switched. Thus, for example, as shown in FIG. 14 (A), in the normal case where the aspect ratio is converted by separating both cylindrical lenses 515a and 515b and the final image is set to 16: 9, one post-conversion One video pixel EE is formed by using the video pixel PE ′ as one block pixel, and the shape of each image video element can be a 1: 1 square. On the other hand, for example, as shown in FIG. 14B, in the non-normal case in which the final image is kept at the original 4: 3 without performing aspect ratio conversion by bringing both cylindrical lenses 515a and 515b into close contact, One video pixel EE is formed by using two video pixels PE ′ as one block pixel, and a higher definition image can be obtained. The image processing unit 530 determines whether to perform image processing for an aspect ratio of 16: 9 or to perform image processing for an aspect ratio of 4: 3 based on a signal from the drive mechanism 540, and the image display device 11. To make appropriate image formation.

  Image processing according to the presence or absence of aspect ratio conversion in the above case will be described with reference to the flowchart of FIG. First, when the virtual image display device 500 is activated, the image processing unit 530 reads position information of each of the cylindrical lenses 515a and 515b from the drive mechanism 540 (step S1). If it is determined from the information that the cylindrical lenses 515a and 515b are at the positions PT1 and PS1, respectively (step S2: Yes), the image processing unit 530 is a normal on-pattern that performs the aspect ratio conversion by the aspect ratio conversion optical system 515. The image processing is performed (step S3). That is, for example, image processing corresponding to the case of FIG. On the other hand, if it is determined from the position information read in step S1 that the cylindrical lenses 515a and 515b are at the positions PT2 and PS2 (step S2: No), the aspect ratio conversion by the aspect ratio conversion optical system 515 is not performed. Image processing according to the pattern is performed (step S4). That is, for example, image processing corresponding to the case of FIG. Note that the image processing unit 530 performs either the image processing with the normal pattern in step S3 or the image processing with the non-normal off pattern in step S4 until the video display operation of the virtual image display device 500 ends. In accordance with the change of the position information read out in step S1, it is continued while switching on and off as appropriate (step S5).

  Further, as a modification of the present embodiment, an aspect ratio conversion optical system 615 configured by cylindrical lenses 615a and 615b as in a virtual image display device 600 shown in FIGS. 16A and 16B is not shown. The drive mechanism may be capable of moving back and forth on the optical path. In this case, for example, the sensor 650 provided in the image forming apparatus 610 transmits information on whether or not the aspect ratio conversion optical system 615 is on the optical path to the image processing unit 630, and the image processing unit 630 By performing image processing in accordance with the presence / absence of the aspect ratio conversion optical system 615, the aspect ratio conversion ratio can be switched on / off as in the case of the virtual image display device 500 shown in FIG. It becomes.

  In the case of this embodiment, in the virtual image display devices 500 and 600, the aspect ratio conversion optical systems 515 and 615 are moved by the drive mechanism 540 or the like, and the conversion ratio of the aspect ratio can be switched on and off, thereby converting the conversion ratio. And the aspect ratio can be set to a desired state.

  In the above description, switching can be performed in two stages, on and off. However, in the virtual image display devices 500 and 600, the aspect ratio conversion optical systems 515 and 615 are configured by an afocal zoom lens, thereby continuously. A magnification conversion may be performed.

[Sixth Embodiment]
Hereinafter, the virtual image display device according to the sixth embodiment will be described with reference to FIG. The virtual image display device 700 according to the present embodiment is a modification of the virtual image display device 100 of the first embodiment, and the same reference numerals as those of the virtual image display device 100 of the first embodiment are the same unless otherwise described. It shall have the function of Accordingly, only the portion corresponding to the first display device for the right eye in the virtual image display device 700 is shown, and the other portions are omitted.

  As shown in FIG. 17A, the virtual image display device 700 includes the image forming device 10 and a light guide device 720 as a set. The light guide device 720 includes a light guide member 721. The light guide member 721 includes a light guide member main body 20a and an angle conversion unit 723 that is an image extraction unit. Note that FIG. 17A corresponds to the AA cross section of the light guide member 721 shown in FIG.

  The overall appearance of the light guide member 721 is formed by a light guide member main body 20a which is a flat plate extending in parallel with the YZ plane in the drawing. Moreover, the light guide member 721 has the 1st reflective surface 21a, the 2nd reflective surface 21b, and the 3rd reflective surface 21c as a side surface. The light guide member 721 includes an upper surface 21e and a lower surface 21f that are adjacent to the first, second, and third reflecting surfaces 21a, 21b, and 21c and that face each other. Furthermore, the light guide member 721 has an angle conversion unit 723 configured by a large number of micromirrors embedded in the light guide member main body 20a at one end in the longitudinal direction, and the light guide member main body at the other end in the longitudinal direction. It has a structure having a prism portion PS formed so as to extend 20a and a third reflecting surface 21c associated therewith.

  The light guide member main body 20a is formed of a light-transmitting resin material or the like, and is a light incident portion that captures image light from the image forming apparatus 10 on a front side plane that is parallel to the YZ plane and faces the image forming apparatus 10. And a light emission surface OS that is a light emission part that emits image light toward the eye EY of the observer. The light guide member body 20a has a rectangular inclined surface RS in addition to the light incident surface IS as a side surface of the prism portion PS, and a mirror layer 25 is formed on the inclined surface RS so as to cover it. Yes. Here, the mirror layer 25 functions as the third reflecting surface 21c which is an incident light bending portion inclined with respect to the light incident surface IS by cooperating with the inclined surface RS. The third reflecting surface 21c bends the image light that is incident from the light incident surface IS and travels in the −X direction as a whole so as to be directed in the + Z direction that is biased in the + X direction as a whole. The main body 20a is securely coupled. Further, in the light guide member main body 20a, the angle conversion part 723, which is a fine structure, is formed in a thin layer along the plane on the back side of the light exit surface OS. The light guide member main body 20a guides image light incident on the inside through the third reflecting surface 21c from the third reflecting surface 21c on the entrance side to the angle converting unit 723 on the back side.

  The first and second reflecting surfaces 21a and 21b of the light guide member 721 are the main surfaces of the flat light guide member main body 20a and are opposite to each other and extend in parallel with the YZ surface as a third reflecting surface. Each of the image lights bent at 21c is totally reflected. The image light reflected by the third reflecting surface 21 c is repeatedly totally reflected by the first and second reflecting surfaces 21 a and 21 b and guided to the back side of the light guide member 721, that is, the + Z side provided with the angle conversion unit 723.

  The angle conversion unit 723 arranged to face the light exit surface OS of the light guide member body 20a is extended along the extension plane of the second reflection surface 21b on the back side (+ Z side) of the light guide member 721. It is formed close to a plane. The angle conversion unit 723 reflects the image light incident through the first and second reflection surfaces 21a and 21b of the light guide member 721 at a predetermined angle and bends it toward the light exit surface OS. That is, the angle conversion unit 723 converts the angle of the image light. Here, it is assumed that the image light that first enters the angle conversion unit 723 is an extraction target as virtual image light. A detailed structure of the angle conversion unit 723 will be described later with reference to FIG.

  In addition, the refractive index n of the transparent resin material used for the light guide member main body 20a is a high refractive index material of 1.5 or more. By using a transparent resin material having a relatively high refractive index for the light guide member 721, it becomes easier to guide the image light inside the light guide member 721, and the angle of view of the image light inside the light guide member 721 is compared. Can be made smaller.

  The image light emitted from the image forming apparatus 10 and incident on the light guide member 721 from the light incident surface IS is uniformly reflected and bent by the third reflecting surface 21c, and the first and second light guide members 721 are bent. The reflection surfaces 21a and 21b are repeatedly totally reflected and proceed in a state of having a certain spread substantially along the optical axis OA. Further, the angle conversion unit 723 is bent at an appropriate angle so that it can be taken out. Is emitted from the light exit surface OS. The image light emitted from the light exit surface OS enters the observer's eye EY as virtual image light. By forming the virtual image light on the retina of the observer, the observer can recognize image light such as video light by the virtual image.

  Hereinafter, the optical path of the image light in the light guide member 721 will be described in detail. As shown in FIG. 17 (A), a component emitted from the central portion of the image display device 11 indicated by a dotted line in the image among the image light emitted from the image display device 11 is an image light GL1, and an alternate long and short dash line in the drawing. The component emitted from the right side (-Z side) of the image display device 11 shown in FIG. 4 is image light GL2, and the left side (+ Z side) of the image display device 11 shown by the two-dot chain line in the drawing. Let the emitted component be image light GL3.

The main components of the image lights GL1, GL2, and GL3 that have passed through the projection optical system 12 are all incident at different angles on the first and second reflecting surfaces 21a and 21b after entering from the light incident surface IS of the light guide member 721, respectively. Repeat reflection. Specifically, of the image lights GL1, GL2, and GL3, the image light GL1 emitted from the central portion of the image display device 11 is reflected by the third reflecting surface 21c as a parallel light flux, and then the standard reflection angle γ _0. Then, the light enters the first reflecting surface 21a of the light guide member 721 and is totally reflected. Thereafter, the image light GL1 is, while maintaining the standard reflection angle gamma _0, the first and second reflecting surfaces 21a, repeating total reflection at 21b. The image light GL1 is totally reflected N times (N is a natural number) on the first and second reflection surfaces 21a and 21b, and enters the central portion 723k of the angle conversion unit 723. The image light GL1 is reflected at a predetermined angle at the central portion 723k and is emitted from the light exit surface OS as a parallel light flux in the direction of the optical axis AX perpendicular to the YZ plane including the light exit surface OS. The image light GL2 emitted from one end side (−Z side) of the image display device 11 is reflected by the third reflecting surface 21c as a parallel light beam, and then has the maximum reflection angle γ ₊ and the first reflecting surface of the light guide member 721. It is incident on 21a and totally reflected. The image light GL2 is totally reflected, for example, NM times (M is a natural number) on the first and second reflection surfaces 21a and 21b, and is predetermined in the peripheral portion 723h on the innermost side (+ Z side) of the angle conversion unit 723. The light is reflected at an angle and emitted from the light exit surface OS as a parallel light beam in a predetermined angle direction. The exit angle at this time is such that it is returned to the third reflecting surface 21c side and becomes an obtuse angle with respect to the + Z axis. The image light GL3 emitted from the other end side (+ Z side) of the image display device 11 is reflected by the third reflecting surface 21c as a parallel light beam, and then has the minimum reflection angle γ ₋ and the first reflecting surface of the light guide member 721. It is incident on 21a and totally reflected. The image light GL3 is totally reflected, for example, N + M times at the first and second reflecting surfaces 21a and 21b, and is reflected at a predetermined angle by the peripheral portion 723m closest to the entrance side (−Z side) of the angle conversion portion 723, The light is emitted as a parallel light beam from the emission surface OS in a predetermined angular direction. The exit angle at this time is such that it is away from the third reflecting surface 21c side, and is an acute angle with respect to the + Z axis. Since the light beam components constituting the image light other than the image light GL1, GL2, and GL3 are similarly guided and emitted from the light exit surface OS, illustration and description thereof are omitted.

Here, as an example of the value of the refractive index n of the transparent resin material used for the light guide member 721, when n = 1.5, the critical angle γ _c is γ _c ≈41.8 °, and n = Assuming 1.6, the value of the critical angle γ _c is γ _c ≈38.7 °. The light guide member for the necessary image light by setting the minimum reflection angle γ ₋ of the reflection angles γ ₀ , γ ₊ , γ ₋ of each image light GL 1, GL 2, GL 3 to a value larger than the critical angle γ _c. The total reflection condition in 721 can be satisfied.

  Hereinafter, the structure of the angle conversion unit 723 and the bending of the optical path of the image light by the angle conversion unit 723 will be described in detail with reference to FIG.

  First, the structure of the angle conversion unit 723 will be described. The angle conversion unit 723 includes a large number of linear reflection units 723c arranged in a stripe shape. That is, as shown in FIGS. 18A to 18C, the angle conversion unit 723 includes a plurality of elongated reflection units 723c extending in the Y direction in the extending direction of the light guide member 721, that is, in the Z direction at a predetermined pitch PT. Is made up of. Each reflection unit 723c is a first reflection surface 723a that is one reflection surface portion disposed on the back side, that is, the optical path downstream side, and another one reflection surface portion that is disposed on the entrance side, that is, the optical path upstream side. The second reflection surface 723b is included in one set. Among these, at least the second reflection surface 723b is a partial reflection surface capable of transmitting a part of light, and allows the observer to observe the external image in a see-through manner. Each reflection unit 723c has a V shape or a wedge shape in the XZ sectional view by the adjacent first and second reflection surfaces 723a and 723b. That is, the first and second reflection surfaces 723a and 723b are inclined at different angles (that is, different angles with respect to the YZ plane) with respect to the second reflection surface 21b, and each of the first reflection surfaces 723a is The second reflection surface 723b extends along a direction (X direction) substantially perpendicular to the second reflection surface 21b, and each second reflection surface 723b forms a predetermined angle (relative angle) ζ with respect to the corresponding first reflection surface 723a. Extending in the direction. Here, the relative angle ζ is assumed to be, for example, 54.7 ° in a specific example.

  In the specific example shown in FIG. 18A and the like, the first reflecting surface 723a is substantially perpendicular to the second reflecting surface 21b, but the direction of the first reflecting surface 723a is the light guide member. 721 is appropriately adjusted according to the specification of 721, and makes any inclination angle within a range of, for example, 80 ° to 100 ° clockwise with respect to the second reflecting surface 21b with respect to the −Z direction. And can. In addition, the direction of the second reflecting surface 723b can be any tilt angle within a range of, for example, 30 ° to 40 ° clockwise with respect to the −Z direction with respect to the second reflecting surface 723b. . As a result, the second reflecting surface 723b has any relative angle within the range of 40 ° to 70 ° with respect to the first reflecting surface 723a.

  Hereinafter, bending of the optical path of the image light by the angle conversion unit 723 will be described. Here, of the image light, the image light GL2 and the image light GL3 that enter the both ends of the angle conversion unit 723 are shown, and the other optical paths are the same as these, so illustrations thereof are omitted.

First, as shown in FIGS. 18A and 18B, the image light GL2 guided at the reflection angle γ ₊ having the largest total reflection angle among the image light is the light incident surface IS of the angle conversion unit 723. (Refer to FIG. 17 (A)) is incident on one reflection unit 723c disposed in the peripheral portion 723h farthest from + Z side, and is first reflected by the first reflection surface 723a on the back side, that is, + Z side, The light is reflected by the second reflection surface 723b on the entrance side, that is, the Z side. The image light GL2 that has passed through the reflection unit 723c is emitted from the light exit surface OS shown in FIG. 17A or the like without passing through the other reflection unit 723c. That is, the image light GL <b> 2 is bent to a desired angle by one pass through the angle conversion unit 723 and is taken out to the observer side.

As shown in FIGS. 18A and 18C, the image light GL3 guided at the reflection angle γ ₋ having the smallest total reflection angle is included in the light incident surface IS (see FIG. A) is incident on one reflection unit 723c disposed in the peripheral portion 723m closest to −Z side, and is the first reflection surface 723a on the back side, that is, the + Z side, as in the case of the image light GL2. Then, the light is reflected by the second reflecting surface 723b on the entrance side, that is, the Z side. The image light GL3 that has passed through the reflection unit 723c is also bent to a desired angle and taken out to the viewer side by only one pass through the angle conversion unit 723.

Here, in the case of the two-stage reflection on the first and second reflection surfaces 723a and 723b as described above, as shown in FIGS. 18B and 18C, each image light is incident. The bending angle ψ, which is the angle between the direction and the direction at the time of injection, is ψ = 2 (R−ζ) (R: right angle). That is, the bending angle ψ is constant irrespective of the incident angle with respect to the angle conversion unit 723, that is, the reflection angles γ ₀ , γ ₊ , γ _{− and the} like that are the total reflection angles of the respective image lights. Accordingly, as described above, a component having a relatively large total reflection angle in the image light is incident on the + Z side peripheral portion 723h side of the angle conversion unit 723, and a component having a relatively small total reflection angle is input to the angle conversion unit. Even when the light is incident on the −Z side peripheral portion 723 m of the 723, the image light can be efficiently extracted in an angle state where the image light is collected on the observer's eye EY as a whole. Since the image light is extracted with such an angular relationship, the light guide member 721 can pass the image light only once without passing the image light a plurality of times in the angle conversion unit 723, and the image light can be transmitted with little loss. It can be extracted as virtual image light.

Further, in the optical design such as the shape and refractive index of the light guide member 721 and the shape of the reflection unit 723c constituting the angle conversion unit 723, by appropriately adjusting the angle etc. through which the image light GL2, GL3, etc. are guided, The image light emitted from the light exit surface OS can be incident on the observer's eye EY as virtual image light with the overall symmetry maintained around the basic image light GL1, that is, the optical axis AX. Here, a angle theta ₁₂ relative to the X direction or the optical axis AX of the image light GL2 at one end, and the angle theta ₁₃ relative to the X direction or the optical axis AX of the image light GL3 at the other end, a substantially equal opposite magnitude It shall be. The angles θ ₁₂ and θ ₁₃ correspond to the horizontal field angle φ of the virtual image recognized by the observer. Since the angle θ ₁₂ and the angle θ ₁₃ are equal, the horizontal half field angle θ (that is, φ = 2θ). ) Is θ = θ ₁₂ = θ ₁₃ .

  The specific numerical range of the pitch PT, which is the interval between the reflecting units 723c constituting the angle conversion unit 723, is 0.2 mm or more, more preferably 0.3 mm to 1.3 mm. By being in this range, the image light to be taken out can be prevented from being affected by diffraction in the angle conversion unit 723, and the lattice fringes by the reflection unit 723c can be made inconspicuous for the observer.

  Also in the present embodiment, as shown in FIGS. 19A and 19B, the virtual image display device 700 is desired to have an aspect ratio of 16: 9, for example, by expansion conversion in the aspect ratio conversion optical system 15. It can be adjusted to the state.

[Others]
Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  For example, as shown in FIG. 20, a hologram element 825 may be provided instead of the mirror layer 25 (see FIG. 2A) of the virtual image display device 100. In this case, the image display device 11 has, for example, an LED light source RR that generates light beams of three colors as a light source, and the hologram element 825 has a three-layered hologram layer corresponding to the three colors. Thereby, the hologram element 825 has a function of reflecting each color light from the image display device 11 in a desired direction as a virtual mirror formed in the vicinity of the third reflecting surface 21c. That is, the hologram element 825 can adjust the reflection direction of the image light. With this hologram element 825, image light can be efficiently taken into the light guide member 21. A hologram element can also be formed on the fourth reflecting surface 21d (see FIG. 2A).

  As another example, as shown in FIGS. 21 (A) to 21 (D), the image may be switched so as to rotate 90 ° depending on the use state of the virtual image display device 100. Specifically, as shown in FIG. 21A, when used in a normal state in which an observer is sitting or standing, the virtual image display device 100 moves in the gravity direction G1, that is, in the −Y direction. On the other hand, the horizontal Z direction coincides with the horizontal direction E1 which is the longitudinal direction of the virtual image display device 100, and an image having an aspect ratio of 16: 9 is formed with this direction as the longitudinal direction. On the other hand, as shown in FIG. 21B, when used in an unusual state where an observer is lying on the side, the virtual image display device 100 is in the gravity direction G1, that is, in the −Y direction. The horizontal Z direction coincides with the longitudinal direction E2 which is the short direction of the virtual image display device 100, and an image having an aspect ratio of 16: 9 is formed with this direction as the longitudinal direction. That is, in the state of FIG. 21A, the image forming apparatus forms a horizontally long image having the horizontal direction E1 as the longitudinal direction as shown in FIG. 21C, and in the state of FIG. As shown in FIG. 21 (D), by forming a vertically long image with the vertical direction E2 as the longitudinal direction, the vertical and horizontal directions of the image viewed by the observer are matched with the vertical and horizontal directions of the outside world in any use state. It can be kept in the state. For the formation of such an image, for example, as shown in the fifth embodiment, a virtual image display device 500 (see FIG. 13A, etc.) that can be converted into a plurality of aspect ratios detects a gravity sensor (not shown). This can be achieved by providing That is, first, in accordance with the gravity direction G1 detected by the gravity sensor, it is determined which of the directions E1 and E2 should be the longitudinal direction of the image, and then, according to the determination, the target image is determined. Image processing is performed so that the image can be formed, and the aspect ratio conversion optical system 515 may be appropriately slid by the drive mechanism 540 so that the image can be converted into a corresponding aspect ratio.

  Moreover, in the said embodiment, although each surface is comprised by the plane in the light guide member, it is not restricted to this, A light guide member has a curved surface in part, and forms image light inside once. It may be a relay system configuration. In this case, for example, the entire apparatus can be reduced in size by appropriately adjusting the optical path.

  Further, the aspect ratio conversion or the like may be determined by the content of the image to be projected. For example, when images on the Internet as shown in FIGS. 22 (A), 22 (B), and 22 (C) are projected, a specific homepage image is determined in advance to be suitable for viewing the image. It can be displayed at a vertical and horizontal display magnification. Specifically, in the initial screen shown in FIG. 22A, when an icon ICa for projecting a specific homepage image is selected from a plurality of icon ICs for content selection arranged in a vertically long image, the icon ICa Change the vertical / horizontal display magnification of the image at the same time as is selected. Thus, for example, as shown in FIGS. 22B and 22C, for the images GG1 and GG2 displayed as the homepage image, the display texts A to D of the image GG1 and the images GG2 are displayed. The aspect ratio magnification or the like can be automatically switched so that a horizontally long image having good correspondence with the display contents A to D is displayed. Note that the change shown in FIG. 22B is merely an example in which the aspect ratio is simply replaced with that in FIG. 22A, but the change shown in FIG. This is an example in which conversion is performed at a specific ratio so as to obtain an optimal aspect ratio. As a result of the above changes, for example, as shown in FIG. 22D of the comparative example, the image GG1 and the image GG2 have poor correspondence without being changed from the case of FIG. Can be prevented from being projected. Further, for example, the state shown in FIG. 22B can be a normal horizontally long image, and it is possible to switch from this state to an image in an optimal state for displaying a specific homepage image shown in FIG. In addition, it is possible to perform projection after partially enlarging the content in advance in image processing.

  In addition to automatically changing the vertical / horizontal display magnification of the image, a switch or the like may be provided so that the user manually switches on / off. Further, a mechanism such as a manual dial may be provided to move the lens. For example, this can be realized by providing a manual dial in the drive mechanism 540 shown in FIG.

  In the above embodiment, the illumination light SL from the illumination device 31 is not particularly directed, but the illumination light SL can be provided with directivity corresponding to the position of the liquid crystal display device 32. As a result, the liquid crystal display device 32 can be efficiently illuminated, and luminance unevenness due to the position of the image light GL can be reduced.

  In the above embodiment, the display brightness of the liquid crystal display device 32 is not particularly adjusted, but the display brightness can be adjusted according to the range and overlap of the projection images IM1 and IM2 as shown in FIG. .

  In the above embodiment, the see-through is given priority by setting the reflectance of the half mirror layer 28 provided on the fourth reflecting surface 21d to 20%. However, priority is given to image light by setting the reflectance of the half mirror layer 28 to 50% or more. You can also. When it is not necessary to observe an external image, the light reflectance of the fourth reflecting surface 21d can be made approximately 100%. Moreover, the half mirror layer 28 does not need to be formed on the entire surface of the fourth reflecting surface 21d, and can be formed only in a part of a necessary region. The half mirror layer 28 can also be formed on the third surface 23 c of the light transmission member 23.

  In the above-described embodiment, the transmissive liquid crystal display device 32 or the like is used as the image display device 11. However, the image display device 11 is not limited to the transmissive liquid crystal display device 32, and various devices can be used. . For example, a configuration using a reflective liquid crystal display device is possible, and a digital micromirror device or the like can be used instead of the liquid crystal display device 32. Further, as the image display device 11, a self-luminous element represented by an LED array, an OLED (organic EL), or the like can be used.

  In the virtual image display device 100 of the above-described embodiment, the image forming device 10 and the light guide device 20 are provided one by one corresponding to both the right eye and the left eye, but either the right eye or the left eye. Only the image forming apparatus 10 and the light guide device 20 may be provided only for the monocular type configuration in which an image is viewed with one eye.

  In the above embodiment, the first optical axis AX1 passing through the light incident surface IS and the second optical axis AX2 passing through the light exit surface OS are parallel, but these optical axes AX1 and AX2 are non-parallel. You can also.

  In the above description, the virtual image display device 100 has been specifically described as being a head-mounted display, but the virtual image display device 100 can be modified to a head-up display.

  In the above description, in the first and second reflecting surfaces 21a and 21b, image light is totally reflected and guided by the interface with air without applying a mirror, a half mirror, or the like on the surface. The total reflection includes reflection formed by forming a mirror coat or a half mirror film on the whole or a part of the first and second reflection surfaces 21a and 21b. For example, after the incident angle of the image light satisfies the total reflection condition, the first and second reflection surfaces 21a and 21b are subjected to mirror coating or the like to reflect substantially all the image light. Cases are also included. In addition, as long as image light with sufficient brightness can be obtained, the first and second reflecting surfaces 21a and 21b may be entirely or partially coated with a somewhat transmissive mirror.

  In the above description, the light guide member 21 extends in the horizontal direction in which the eyes EY are arranged. However, the light guide member 21 can be extended in the vertical direction. In this case, the optical panels 110 are arranged in parallel, not in series.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Image display apparatus, 12 ... Projection optical system, 20 ... Light guide apparatus, 21 ... Light guide member, 21a, 21b, 21c, 21d ... 1st-4th reflective surface, 21e ... Upper surface, 21f ... lower surface, 21h, 21i ... end face, 23 ... light transmitting member, 23a, 23b, 23c ... surface, 25 ... mirror layer, 27 ... hard coat layer, 28 ... half mirror layer, 31 ... lighting device, 32 ... liquid crystal display Device 32b Display area 34 Drive control unit 100 Virtual image display device 100A, 100B Display device 110 Optical panel 121 Frame 131, 132 Drive unit 723 Angle conversion unit (Image extraction) Part), 825 ... hologram element, AX1 ... first optical axis, AX2 ... second optical axis, B1 ... light incident part, B2 ... light guide part, B3 ... light emission part, 4 ... fluoroscopic part, EY ... eye, FS ... flat surface, GL ... image light, GL '... external light, GL11, GL12, GL21, GL22 ... image light, IM1, IM2 ... projection image, IS ... light incident surface, L1 , L2, L3 ... lens, OS ... light exit surface, P1 ... first display point, P2 ... second display point, A10 ... first partial region, A20 ... second partial region, SL ... illumination light

Claims (16)

An image display device for forming image light;
A projection optical system for forming a virtual image by the image light emitted from the image display device;
A light incident part that captures the image light that has passed through the projection optical system, and the image light captured from the light incident part are guided by total reflection on the first and second total reflection surfaces that extend opposite to each other. A light guide device comprising: a light guide portion; and a light emitting portion that extracts the image light that has passed through the light guide portion to the outside,
The projection optical system includes a toric optical system that adjusts an aspect ratio of a virtual image in an image area of the image display device.   2. The virtual image according to claim 1, wherein the toric optical system converts the aspect ratio of the virtual image so as to increase a lateral ratio for an observer based on a display aspect ratio of the image display device. Display device.   3. The toric optical system according to claim 2, wherein the toric optical system performs at least one of expansion conversion in a first direction corresponding to a lateral direction for the observer and reduction conversion in a second direction perpendicular to the first direction. The virtual image display device described. The image forming apparatus is disposed on an ear side of an observer who observes the image light,
4. The virtual image display device according to claim 1, wherein the light guide device guides the image light along a lateral direction for the observer. 5.   5. The image display device according to claim 1, wherein an aspect ratio of each shape of a plurality of pixels arranged in the image region is an inverse ratio to a conversion ratio by the toric optical system. The virtual image display device described in 1.   6. The virtual image display device according to claim 5, wherein in the image display device, the plurality of pixels are configured by arranging pixel elements of three segments in a line.   The virtual image display device according to claim 6, wherein the pixel elements of the three segments are three colors of RGB and are arranged in a line in a horizontal direction for an observer.   The virtual image display device according to claim 5, wherein the plurality of pixels are configured by arranging pixel elements of four segments in two rows and two columns.   The virtual image display device according to claim 8, wherein the pixel elements of the four segments are configured by three colors of RGB.   The virtual image display device according to claim 8, wherein the four-segment pixel elements are configured by four colors obtained by adding three colors of RGB to other colors.   An image processing unit that performs conversion processing of an aspect ratio that is an inverse ratio of the conversion ratio of an image signal input from the outside to the image display device in accordance with the conversion ratio of the aspect ratio of the image light by the toric optical system. The virtual image display device according to any one of claims 1 to 10, further comprising:   The virtual image display device according to any one of claims 1 to 11, further comprising a drive mechanism that moves the toric optical system on an optical path of the image light.   The toric optical system has a pair of concave and convex cylindrical lenses arranged in a direction facing a light incident surface of the light guide device that takes in the image light therein, and changes the arrangement of the cylindrical lenses. The virtual image display device according to any one of claims 1 to 12, wherein a conversion ratio of an aspect ratio of the image light is adjusted. The light guide unit has a first reflection surface and a second reflection surface that are arranged in parallel to each other and enable light guide by total reflection,
The light incident portion has a third reflecting surface that forms a predetermined angle with respect to the first reflecting surface;
The virtual image display device according to any one of claims 1 to 13, wherein the light emitting unit includes a fourth reflecting surface that forms a predetermined angle with respect to the first reflecting surface.   The virtual image display device according to claim 14, wherein the light guide device includes a hologram element on at least one of the third reflection surface and the fourth reflection surface.   The light guide device has a plurality of reflection surfaces extending in a predetermined direction, and the image light guided by total reflection at the first and second total reflection surfaces of the light guide unit is reflected by the plurality of reflection surfaces. The virtual image display device according to any one of claims 1 to 13, further comprising an angle conversion unit that bends toward the light emitting unit.

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