JP5682215B2 - Virtual image display device - Google Patents

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.

  In recent years, as a virtual image display device capable of forming and observing a virtual image, such as a head-mounted display that is mounted on a head and used, a type that guides image light from a display element to an observer's pupil by a light guide plate Various proposals have been made.

  As such a light guide plate for a virtual image display device, for example, image light is guided using total reflection, and a plurality of partial reflection surfaces arranged parallel to each other at a predetermined angle with respect to the main surface of the light guide plate. It is known that the image light is reflected and taken out from the light guide plate so that the image light reaches the retina of the observer (see Patent Document 1). Also, as a similar technique, in order to extract the image light, a sawtooth portion is provided on the back side facing the surface from which the image light is extracted, and a reflective layer for extracting the image light is formed on the sawtooth portion. Is also known (see Patent Document 2).

Special table 2003-536102 gazette JP 2004-157520 A

  When the virtual image display device as described in Patent Documents 1 and 2 is used by being mounted on the head, for example, like a spectacle type, the structure regarding the arrangement and size of each element constituting the device There are various design restrictions from the standpoint of design or design. On the other hand, regarding 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.

  Therefore, an object of the present invention is to provide a virtual image display device that can set an aspect ratio to a desired state with respect to image light that enters a viewer's eyes as a virtual image while satisfying design restrictions.

In order to solve the above problems, a virtual image display device according to the present invention includes (a1) an image display element having an image area for forming image light, and (a2) forming a virtual image of the image area of the image display element and a virtual image. A projection optical system including a toric optical system for converting an aspect ratio; (a) an image forming apparatus; and (b) a plurality of reflections that guide image light formed by the image forming apparatus to the inside and extend in a predetermined direction. A virtual image display device according to a conversion ratio of the aspect ratio of the image light by the toric optical system. The image processing unit further includes an image processing unit that performs conversion processing of an aspect ratio that is a reverse ratio to the conversion ratio for an image signal input to the image display element from the outside.

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. Further, by image processing that compensates for the conversion of the aspect ratio by the toric optical system, the image recognized by the observer can be kept in the original image by the image signal at the time of external input.

  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 based on the aspect ratio in the image area of the image display element. 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 disposed on the ear side of the observer who observes the image light, and (b) the light guide plate emits the image light along the lateral 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 element, each shape of the plurality of pixels arranged in the image region is a rectangle having an aspect ratio opposite to the conversion ratio by the toric optical system, and the converted virtual image The image pixel is a square. 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 element, a plurality of pixels are configured by arranging pixel elements of three segments in a line. In this case, for example, a color image can be formed by configuring three segments with three colors of RGB.

  In still another aspect of the present invention, in the image display element, a plurality of pixels are configured by arranging pixel elements of four segments in two rows and two 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 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 the light incident surface of the light guide plate that takes in the image light therein, The conversion ratio of the aspect ratio of the image light is adjusted by changing the arrangement. 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.

(A) is sectional drawing which shows the virtual image display apparatus which concerns on 1st Embodiment, (B) is a front view of a light-guide plate, (C) is a top view. (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, (C) is a perspective view of one set of cylindrical lenses which comprise an aspect ratio conversion optical system. . (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.

[First Embodiment]
Hereinafter, a virtual image display device according to a first embodiment of the present invention will be described with reference to the drawings.

[A. Structure of light guide plate and virtual image display device]
A virtual image display device 100 according to this embodiment shown in FIG. 1A is applied to a head-mounted display, and includes an image forming device 10 and a light guide plate 20 as a set. 1A corresponds to the AA cross section of the light guide plate 20 shown in FIG.

  The virtual image display device 100 allows an observer to recognize image light based on a virtual image, and allows the observer to observe an external image in a see-through manner. The image forming apparatus 10 and the light guide plate 20 are usually provided one by one corresponding to the right eye and the left eye of the observer, but the right eye and the left eye are symmetrical in the right eye and the right eye here. For the left eye, the illustration is omitted. The virtual image display device 100 as a whole has, for example, an appearance (not shown) like general glasses. In this case, the image forming apparatus 10 is disposed close to the observer's ear.

  The image forming apparatus 10 includes an image display element 11 and a projection optical system 12. The image display element 11 is composed of a transmissive liquid crystal device, for example, and spatially modulates illumination light from a light source (not shown) to form image light to be displayed such as a moving image. The projection optical system 12 includes a collimator lens 13 and an aspect ratio conversion optical system 15, and forms a virtual image by emitting image light toward the light guide plate 20. The material of the lenses constituting the collimating lens 13 and the aspect ratio converting optical system 15 can be either glass or plastic. Among these, the collimating lens 13 converts the image light emitted from each point on the image display element 11 into a light beam in a parallel state. The aspect ratio conversion optical system 15 is a toric optical system composed of a plurality of lenses having toric surfaces with different curvature radii depending on the meridian direction, and the aspect ratio conversion optical system 15 has a curvature radius in the vertical direction and the horizontal direction. By using lenses having different optical surfaces, the aspect ratio can be converted by adjusting the angle of view. Here, as an example, the aspect ratio, that is, the aspect ratio in the image area of the image display element 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 optical system 15 will be described later.

  As shown in FIGS. 1A to 1C, a light guide plate 20 according to this embodiment includes a light guide plate main body 20a, an incident light bending portion 21, and an angle conversion portion 23 that is an image extraction portion. Is provided. The light guide plate 20 emits the image light formed by the image forming apparatus 10 as virtual image light toward the observer's eye EY and recognizes it as an image.

  The overall appearance of the light guide plate 20 is formed by a light guide plate body 20a which is a flat plate extending parallel to the YZ plane in the drawing. In addition, the light guide plate 20 has an angle conversion unit 23 constituted by a large number of micromirrors embedded in the light guide plate body 20a at one end in the longitudinal direction, and extends the light guide plate body 20a at the other end in the longitudinal direction. The prism portion PS formed as described above and the incident light bending portion 21 associated therewith are configured.

  The light guide plate main body 20a is a light incident portion that is formed of a light-transmitting resin material or the like and takes in 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. It has a certain light incident surface IS and a light emitting surface OS which is a light emitting portion for emitting image light toward the observer's eye EY. The light guide plate main 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 21a is formed on the inclined surface RS so as to cover it. . Here, the mirror layer 21a functions as the incident light bending portion 21 inclined with respect to the light incident surface IS by cooperating with the inclined surface RS. The incident light bending section 21 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 plate main body 20a, the angle conversion part 23, 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 plate main body 20a guides the image light incident inside through the incident light bending portion 21 from the incident light bending portion 21 to the back angle conversion portion 23 to the angle conversion portion 23. The light guide 22 is provided.

  The light guide 22 is a main surface of the flat light guide plate main body 20a and is two planes facing each other and extending in parallel to the YZ plane, and totally reflects the image light bent by the incident light bending portion 21, respectively. The first total reflection surface 22a and the second total reflection surface 22b are provided. Here, it is assumed that the first total reflection surface 22 a is on the back side far from the image forming apparatus 10 and the second total reflection surface 22 b is on the front side close to the image forming apparatus 10. In this case, the second total reflection surface 22b is a common surface portion with the light incident surface IS and the light exit surface OS. The image light reflected by the incident light bending portion 21 first enters the second total reflection surface 22b and is totally reflected. Next, the image light enters the first total reflection surface 22a and is totally reflected. Hereinafter, by repeating this operation, the image light is guided to the back side of the light guide plate 20, that is, the + Z side where the angle conversion unit 23 is provided. That is, the light guide plate 20 guides the image light along the lateral direction for the observer.

  The angle conversion unit 23 disposed to face the light exit surface OS of the light guide plate main body 20a is arranged along the extended plane of the first total reflection surface 22a on the back side (+ Z side) of the light guide unit 22. It is formed close to the extension plane. The angle conversion unit 23 reflects the image light incident through the first and second total reflection surfaces 22a and 22b of the light guide unit 22 at a predetermined angle and bends it toward the light exit surface OS. That is, the angle conversion unit 23 converts the angle of the image light. Here, it is assumed that the image light first incident on the angle conversion unit 23 is an extraction target as virtual image light. The detailed structure of the angle conversion unit 23 will be described later with reference to FIG.

  In addition, the refractive index n of the transparent resin material used for the light-guide plate main-body part 20a shall be 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 plate 20, it becomes easier to guide the image light inside the light guide plate 20, and the angle of view of the image light inside the light guide plate 20 is made relatively small. be able to.

  The image light emitted from the image forming apparatus 10 and incident on the light guide plate 20 from the light incident surface IS is uniformly reflected and bent by the incident light bending portion 21, and the first and second light guide portions 22. The total reflection surfaces 22a and 22b are repeatedly totally reflected and proceed in a state of having a constant spread substantially along the optical axis OA, and further, the angle conversion unit 23 is bent at an appropriate angle so that it can be taken out. Finally, the light exits 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.

[B. Optical path of image light in the light guide plate]
Hereinafter, the optical path of the image light in the light guide plate 20 will be described in detail. As shown in FIG. 1A, a component emitted from the central portion of the emission surface 11a indicated by a dotted line in the image light emitted from the emission surface 11a of the image display element 11 is an image light GL1. The component emitted from the right side (-Z side) of the drawing surface 11a indicated by the alternate long and short dash line in the figure is the image light GL2, and the left side (+ Z side) of the periphery of the emission surface 11a indicated by the two-dot chain line in the drawing. ) Is emitted as image light GL3.

The main components of the image lights GL1, GL2, and GL3 that have passed through the projection optical system 12 are incident on the first and second total reflection surfaces 22a and 22b at different angles after entering from the light incident surface IS of the light guide plate 20, respectively. Repeat total reflection. Specifically, among the image lights GL1, GL2, and GL3, the image light GL1 emitted from the central portion of the emission surface 11a of the image display element 11 is reflected by the incident light bending portion 21 as a parallel light flux, The light enters the second total reflection surface 22b of the light guide unit 22 at the standard reflection angle γ ₀ and is totally reflected. Thereafter, the image light GL1 is, while maintaining the standard reflection angle gamma _0, first and second total reflection surface 22a, repeating total reflection at 22b. The image light GL1 is totally reflected N times (N is a natural number) on the first and second total reflection surfaces 22a and 22b, and enters the central portion 23k of the angle conversion unit 23. The image light GL1 is reflected at a predetermined angle at the central portion 23k, and is emitted from the light exit surface OS as a parallel light flux in the optical axis AX direction perpendicular to the YZ plane including the light exit surface OS. The image light GL2 emitted from one end side (−Z side) of the emission surface 11a of the image display element 11 is reflected by the incident light bending portion 21 as a parallel light beam, and then has a maximum reflection angle γ ₊ and the light guide portion 22. Is incident on the second total reflection surface 22b and totally reflected. The image light GL2 is totally reflected, for example, NM times (M is a natural number) on the first and second total reflection surfaces 22a and 22b, and in the peripheral portion 23h on the farthest side (+ Z side) of the angle conversion unit 23. The light is reflected at a predetermined angle and is 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 incident light bending portion 21 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 emission surface 11a of the image display element 11 is reflected by the incident light bending portion 21 as a parallel light beam, and then has a minimum reflection angle γ ₋ and the light guide portion 22. Is incident on the second total reflection surface 22b and totally reflected. The image light GL3 is totally reflected, for example, N + M times at the first and second total reflection surfaces 22a and 22b, and is reflected at a predetermined angle by the peripheral portion 23m on the most entrance side (−Z side) of the angle conversion portion 23. The light is emitted as a parallel light flux from the light exit surface OS in a predetermined angle direction. The exit angle at this time is such that it is away from the incident light bending portion 21 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 incident light bending part 21 and the light guide part 22, when n = 1.5, the value of the critical angle γ _c is γ _c ≈41. .8 ° and n = 1.6, the critical angle γ _c is γ _c ≈38.7 °. Each image light GL1, GL2, reflection angle gamma ₀ of _GL3, γ _+, γ _- reflection angle is the smallest among the gamma _- a by a value larger than the critical angle gamma _c, the light guide portion for the required image light 22 to satisfy the total reflection condition.

[C. (Structure of angle converter and bending of optical path by angle converter)
Hereinafter, the structure of the angle conversion unit 23 and the bending of the optical path of the image light by the angle conversion unit 23 will be described in detail with reference to FIG.

  First, the structure of the angle conversion unit 23 will be described. The angle conversion unit 23 includes a large number of linear reflection units 23c arranged in a stripe shape. That is, as shown in FIGS. 2A to 2C, the angle conversion unit 23 includes a plurality of elongated reflection units 23c extending in the Y direction at a predetermined pitch PT in the direction in which the light guide unit 22 extends, that is, in the Z direction. Is made up of. Each reflection unit 23c is a first reflection surface 23a 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 reflecting surface 23b is provided as a set. Among these, at least the second reflection surface 23b is a partial reflection surface capable of transmitting a part of light, and allows an observer to observe an external image in a see-through manner. Each reflection unit 23c is formed in a V shape or a wedge shape in the XZ sectional view by the adjacent first and second reflection surfaces 23a and 23b. In other words, the first and second reflection surfaces 23a and 23b are inclined at different angles (that is, different angles with respect to the YZ plane) with respect to the first total reflection surface 22a, and each first reflection surface 23a is inclined. Extends along a direction (X direction) substantially perpendicular to the first total reflection surface 22a, and each second reflection surface 23b has a predetermined angle (relative angle) with respect to the corresponding first reflection surface 23a. ) It extends in the direction of α. Here, the relative angle α is assumed to be, for example, 54.7 ° in a specific example.

  In the specific example shown in FIG. 2A and the like, the first reflecting surface 23a is assumed to be substantially perpendicular to the first total reflecting surface 22a, but the direction of the first reflecting surface 23a is guided. Any tilt angle within a range of, for example, 80 ° to 100 ° clockwise with respect to the −Z direction with respect to the first total reflection surface 22a is appropriately adjusted according to the specifications of the optical plate 20. It can be made. Further, the direction of the second reflecting surface 23b makes any inclination angle within a range of, for example, 30 ° to 40 ° clockwise with respect to the −Z direction with respect to the first total reflecting surface 22a. And can. As a result, the second reflecting surface 23b has any relative angle within the range of 40 ° to 70 ° with respect to the first reflecting surface 23a.

  Hereinafter, bending of the optical path of the image light by the angle conversion unit 23 will be described. Here, among the image light, the image light GL2 and the image light GL3 that enter the both ends of the angle conversion unit 23 are shown, and the other optical paths are the same as these, so the illustration and the like are omitted.

First, as shown in FIGS. 2A and 2B, 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 in the angle conversion unit 23. The light is incident on one reflection unit 23c disposed in the peripheral portion 23h on the + Z side farthest from (refer to FIG. 1A), and is first reflected by the first reflection surface 23a on the back side, that is, the + Z side, The light is reflected by the second reflecting surface 23b on the entrance side, that is, the -Z side. The image light GL2 that has passed through the reflection unit 23c is emitted from the light exit surface OS shown in FIG. 1A or the like without passing through the other reflection unit 23c. That is, the image light GL <b> 2 is bent to a desired angle by one pass through the angle conversion unit 23 and extracted to the viewer side.

Also, as shown in FIGS. 2A and 2C, 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) the first reflection surface 23a which is incident on one reflection unit 23c arranged in the peripheral portion 23m on the −Z side closest to the reference) and is first, as in the case of the image light GL2. Then, the light is reflected by the second reflecting surface 23b on the entrance side, that is, the -Z side. The image light GL3 that has passed through the reflection unit 23c is also bent to a desired angle and taken out to the observer side by only one pass through the angle conversion unit 23.

Here, in the case of the two-stage reflection on the first and second reflecting surfaces 23a and 23b as described above, as shown in FIGS. 2B and 2C, 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−α) (R: right angle). That is, the bending angle ψ is constant regardless of the incident angle with respect to the angle conversion unit 23, that is, the values of 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 made incident on the + Z side peripheral portion 23h side of the angle conversion unit 23, and a component having a relatively small total reflection angle is incident on the angle conversion unit. Even when the light beam is incident on the peripheral portion 23m side on the −Z side of the image 23, the image light can be efficiently extracted in an angle state so as to collect the image light as a whole on the eye EY of the observer. Since the configuration is such that the image light is extracted with such an angle relationship, the light guide plate 20 can pass the image light only once without passing through the angle conversion unit 23 a plurality of times, and the image light can be passed through the virtual image with little loss. It can be extracted as light.

In addition, in the optical design such as the shape and refractive index of the light guide 22 and the shape of the reflection unit 23c constituting the angle conversion unit 23, 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 ₂ with respect to the X direction or the optical axis AX of the image light GL2 at one end, the angle theta ₃ with respect 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 ₂ and θ ₃ correspond to the horizontal field angle φ of the virtual image recognized by the observer. Since the angle θ ₂ and the angle θ ₃ are equal, the horizontal half field angle θ (that is, φ = 2θ). ) Is θ = θ ₂ = θ ₃ .

  The specific numerical range of the pitch PT, which is the interval between the reflecting units 23c constituting the angle conversion unit 23, is 0.2 mm or more, and 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 23, and the lattice fringes by the reflection unit 23c can be made inconspicuous for the observer.

[D. Aspect ratio conversion optical system structure and aspect ratio conversion)
Hereinafter, the structure and function of the aspect ratio converting optical system 15 will be described with reference to FIGS. Here, as described above, the aspect ratio or aspect ratio of the image area of the image display element 11 is set to 4: 3, and the aspect ratio or aspect ratio of 16: 9 is obtained by the aspect ratio conversion by the aspect ratio conversion optical system 15. To be recognized by the observer. That is, as conceptually shown in FIG. 4A, a panel corresponding to an image recognized by an observer is provided by arranging an aspect ratio conversion optical system 15 that performs angle conversion of a light beam only in the horizontal direction. The image PP is converted from an aspect ratio of 4: 3 to an aspect ratio of 16: 9. As conceptually shown in FIG. 4B 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 element 11 remains 4: 3.

  3A is a cross-sectional view of the virtual image display device 100 viewed from the Y direction, FIG. 3B 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 that is the horizontal direction of the image display element 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 element 11 perpendicular to the first direction D1 corresponds to the vertical direction E2 of the panel image PP.

  The aspect ratio conversion 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 side opposite to the light source. 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 plate 20 directly or indirectly. Since each cylindrical lens 15a, 15b has the shape and arrangement as described above, a difference in cross-sectional shape may cause a diverging / converging action of light passing through, that is, an expansion / reduction action for image light. There may be no or almost none. In the illustrated cylindrical lenses 15a and 15b, 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. 3A and 3B, 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 with an infinite focal length. And exits while maintaining the parallelism of the incident parallel light flux. That is, 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. 3A, 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. 3B, that is, in the XY plane, the image light GL1 and the like are incident as a parallel light flux and emitted as a substantially parallel light flux. Here, 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. 3A 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 is 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 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. In this case, for example, the component emitted from the peripheral side of the image display element 11 such as the image light GL2 in the image light is symmetric with respect to the one intersecting the optical axis XX. The light is emitted in a direction having an angle component more inclined with respect to the optical axis XX. When more specifically described with reference to FIG. 4 (C), the first, the image light GL2 is, when inclined at the incident angle theta ₀ with respect to the optical axis XX from the -Z side is a peripheral side enters the convex cylindrical lenses 15a The light beam is emitted from the + Z side at an emission angle θ that has a larger inclination than the incident angle θ _{0 with} respect to the optical axis XX by the convex cylindrical lens 15a and the concave cylindrical lens 15b which are afocal systems. The emission angle θ is equal to the value of the horizontal half angle of view θ of the virtual image shown in FIG. Similarly, the image light GL3 is + inclined by an incident angle theta ₀ with respect to the optical axis XX incident on Anamorphic optical system 15 from the Z-side, -Z side large emission angle theta of inclination than the incident angle theta ₀ Is injected from. As described above, as a result of passing through the aspect ratio conversion optical system 15 and the emission angle θ larger than the incident angle θ ₀ in the horizontal direction, that is, the angular magnification is increased, the angle of view at the time of emission of the image light is increased. 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. 3B, 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, image light GLa emitted from the −Y side of the image display element 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 plate 20. Note that, as illustrated in FIG. 3A, 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 unit 22 is narrowed. On the other hand, as shown in FIG. 3B, when neither expansion nor reduction is performed, the width of each parallel light beam passing through the light guide unit 22 does not change.

  Hereinafter, the shape of the pixels constituting the image corresponding to the aspect ratio conversion will be described. First, FIG. 5A 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 element 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 element 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 element 11. On the other hand, FIG. 5B 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. 5B, each picture pixel PE ′ of the panel image PP corresponds to 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. 5A 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. 5B 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 element 11, that is, the shape of the pixel PE is previously set to be vertically long 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. 6 (A) and 6 (B), a set of vertically long pixel elements R1, G1, and B1 of RGB (red, green, and blue) arranged in a horizontal row is used 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. 6C and 6D, pixel elements R1, G1, and B1 of three colors RGB (red, green, and blue) can be arranged in a vertical line. 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, as shown in FIGS. 6E and 6F, for example, three pixel elements of RGB (red, green, blue) are arranged in four rectangular squares to obtain one The pixel PE can also be configured. 6 (E) and 6 (F), for example, R and B are arranged one by one and G is two, that is, the 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. 6F). As shown in FIGS. 6G and 6H, 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.6 (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.

  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 element 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). Thereby, for example, the horizontal width WD of the image forming apparatus 10 including the image display element 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 above embodiment and each modification, the aspect ratio of the display image on the image display element 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.

[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

  7A is a cross-sectional view of the virtual image display device 200 as viewed from the Y direction, and FIG. 7B 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 element 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 which 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 a 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. 7A, 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. 7B, 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. 8 (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 an 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. 8 (B), 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 which 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 illustrated in FIG. 9A, the virtual image display device 400 includes an image processing unit 430 in addition to the image forming device 10 and the light guide plate 20.

  The image processing unit 430 performs image processing on an image signal input to the image display element 11 from the outside. Specifically, the image processing unit 430 performs necessary signal processing of the image signal and, as shown in FIG. 9B, displays the original video P1 corresponding to the image signal input from the outside as an image display element. The horizontal magnification conversion process is performed so that the panel input video P2 matches the shape of the eleven image regions. At this time, the conversion process is performed so that the display video P3 which is the final image recognized by the observer returns to the state of the original video P1. Specifically, for example, the aspect ratio of the original image P1 is 16: 9, the aspect ratio of the panel input image P2, that is, the aspect ratio of the image area of the image display element 11, is 4: 3, and the display image P3 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 P1 so as to be reduced to 3/4 times in the horizontal direction, that is, the longitudinal direction L1, in accordance with the conversion rate in the aspect ratio conversion optical system 15. As a result, as shown in the figure, the video in the panel input video P2 becomes relatively long because it contracts in the longitudinal direction L1 compared to the original video P1, but in the display video P3 that is the final image, the aspect ratio conversion is performed. Therefore, the original image P1 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 P3 recognized by the observer can be left as it is without being expanded and contracted vertically and horizontally with respect to the original video P1 by the video signal at the time of input from the outside.

[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 shown in FIGS. 10A and 10B, 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 plate 20.

  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. 10B, 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. 10A to 10F, 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. In other words, the cylindrical lens 515a can be reciprocated between the first position PT1 shown in FIG. 10A and the second position PT2 shown in FIG. 10B by the driving mechanism 540, 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. In addition, the image processing unit 530 performs image processing on an image signal input to the image display element 11 from the outside. At this time, the image processing unit 530 should perform the image processing based on 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. 10A is the normal on-pattern image processing, and the close contact of FIG. 10B. 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. 10A, 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. 10C, the lenses 515a and 515b have a refractive power and are separated from each other in the cross section parallel to the XZ plane, and the aspect ratio converting optical system 515 is 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. 10D, for the cross section parallel to the XY plane, for example, the image light GLa 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. 10B, when the cylindrical lenses 515a and 515b are at the second positions PT2 and PS2, respectively, 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 element 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. 11 (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. 11B, in the non-normal case in which the final video is kept at the original 4: 3 without performing the 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 element 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. 13A and 13B 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.

[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.

  In addition, the pitch PT of the arrangement of the reflection units 23c constituting the angle conversion unit 23 is not limited to the case where all the first reflection surfaces 23a are the same, and there is a certain difference in the pitch PT. Shall also be included.

  In the above description, a transmissive liquid crystal device is used as an example of the image display element 11. However, the image display element is not limited to a transmissive liquid crystal device, and various other devices can be used. For example, a configuration using a reflective liquid crystal panel is possible, and a digital micromirror device or the like can be used instead of the image display element 11. Further, a configuration using a self-luminous element typified by an LED array, OLED (organic EL), laser diode, or the like is also possible. Furthermore, a configuration using a laser scanner in which a laser light source and a polygon mirror or other scanner are combined is possible.

  In the above description, the virtual image display device 100 is configured to provide the image forming device 10 and the light guide plate 20 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 plate 20 may be provided so that the image is viewed with one eye.

  In the above description, a see-through type virtual image display device is described, but the angle conversion unit 23 can also be applied to a virtual image display device other than the see-through type. When it is not necessary to observe an external image, the light reflectance of both the first and second reflecting surfaces 23a and 23b can be set to approximately 100%.

  In the above description, the light incident surface IS and the light exit surface OS are arranged on the same plane. However, the present invention is not limited to this. For example, the light incident surface IS is the same plane as the first total reflection surface 22a. The light emission surface OS may be disposed on the same plane as the second total reflection surface 22b.

  In the above description, the first direction D1 and the second direction D2 of the image forming apparatus 10 coincide with the Z direction and the Y direction, which are the horizontal direction E1 and the vertical direction E2 on the corresponding viewer side, respectively. Are not necessarily coincident, and the directions D1 and D2 may be directions other than the Z direction and the Y direction.

  In the above description, the mirror layer 21a constituting the incident light bending portion 21 and the inclination angle of the slope RS are not particularly mentioned, but the present invention is not limited to other specifications of the application of the mirror layer 21a and the like with respect to the optical axis OA. Various values can be used depending on the value.

  In the above description, the angle conversion unit 23 forms the first and second reflection surfaces 23a and 23b as reflection surfaces, respectively. However, the angle conversion unit 23 is formed by only one type of conventional reflection surface. The image light may be taken out. In this case, a component extracted after passing through the reflecting surface a plurality of times is present in the image light.

  In the above description, the V-shaped groove formed by the reflection unit 23c is illustrated with the tip sharpened, but the V-shaped tip is cut flat or the tip is rounded. Those which are substantially V-shaped grooves are also included. Further, even when the cut portion is larger and trapezoidal, the reflection unit 23c is configured as long as the first reflection surface 23a and the second reflection surface 23b are tapered. It becomes.

  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 total reflection surfaces 22a and 22b, 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 in the present invention includes reflection formed by forming a mirror coat or a half mirror film on the whole or a part of the first and second total reflection surfaces 22a and 22b. For example, the case where the incident angle of the image light satisfies the total reflection condition and the whole or a part of the total reflection surfaces 22a and 22b is subjected to mirror coating or the like to reflect substantially all the image light is included. . Moreover, as long as image light with sufficient brightness can be obtained, the whole or a part of the total reflection surfaces 22a and 22b may be coated with a somewhat transmissive mirror.

  In addition to the colored pixels such as the pixel elements R1, G1, and B1 described above, white (non-colored) pixel elements for increasing the brightness can be incorporated into the sub-pixels constituting each pixel PE.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Image display element, 12 ... Projection optical system, 13 ... Collimate lens, 15, 215, 315, 515, 615 ... Aspect ratio conversion optical system (toric optical system), 15a, 215a, 515a, 615a ... convex cylindrical lens, 15b, 215b, 515b, 615b ... concave cylindrical lens, 20 ... light guide plate, 20a ... light guide plate body part, 22 ... light guide part, 22a, 22b ... total reflection surface, 23 ... angle conversion part, 23a, 23b ... reflective surface, 23c ... reflective unit, 100 ... virtual image display device, 430 ... image processing unit, 540 ... drive mechanism, PD ... image area, PP ... panel image, PE ... pixel, PE '... video pixel, R1 , G1, B1 ... Pixel elements, EY ... Eye, GL1, GL2, GL3, GLa ... Image light, D1 ... First Direction, D2 ... Second direction

Claims (10)

An image having an image display element having an image area for forming image light, and a projection optical system including a toric optical system that forms a virtual image of the image area of the image display element and converts an aspect ratio of the virtual image A forming device;
A light guide plate that guides the image light formed by the image forming apparatus to the inside and has a plurality of reflection surfaces extending in a predetermined direction, reflects the image light by the plurality of reflection surfaces, and emits the image light to the outside;
Equipped with a,
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 element in accordance with the conversion ratio of the aspect ratio of the image light by the toric optical system. A virtual image display device. The projection optical system has a collimating lens that converts the image light emitted from the image display element into parallel light and emits the parallel light to the toric optical system.
The virtual image display device according to claim 1, wherein the toric optical system includes a plurality of lenses having optical surfaces having different radii of curvature in the vertical direction and the horizontal direction in the toric optical system. 3. The aspect ratio of 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 an aspect ratio in an image region of the image display element . The virtual image display device according to any one of the above. The toric optical system of the reduction conversion in the second direction perpendicular to the decompression conversion and the first direction about the first direction corresponding to the lateral direction in the said observer, performs at least one, in claim 3 The virtual image display device described. The image forming apparatus is disposed on an ear side of an observer who observes the image light,
The light guide plate along the lateral direction in the said observer directs the image light, the virtual image display device according to any one of claims 1 to 4. In the image display element, each shape of the plurality of pixels arranged in the image region is a rectangle having an aspect ratio opposite to the conversion ratio by the toric optical system, and the image pixel of the virtual image after conversion is a square The virtual image display device according to any one of claims 1 to 5, wherein The virtual image display device according to claim 6 , wherein in the image display element, 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 in the image display element, 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 any one of claims 1 to 8, 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 the light incident surface of the light guide plate that takes in the image light therein, and the arrangement of the cylindrical lenses is changed. The virtual image display device according to any one of claims 1 to 9, wherein a conversion ratio of an aspect ratio of the image light is adjusted.

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