JP2012068440A - Virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device able to extract image light in a satisfactory state by preventing image deterioration due to uneven brightness while restraining a loss in a quantity of light.SOLUTION: In an angle conversion part 23, an upper limit size is provided while a condition required to take an image into an eye EY with regard to the width L of the angle conversion part 23 in the arrangement direction of a reflection unit 23c is obtained taking a lateral angle of view, an eye size, etc., into account. Thereby an excessive loss in a quantity of image light in the angle conversion part 23 is restrained, image deterioration due to uneven brightness, etc., can be prevented, and image light can be extracted in a satisfactory state.

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 that enable formation and observation of virtual images, such as a head-mounted display, have been proposed that guide video light from a display element to an observer's pupil using a light guide plate. As a light guide plate for such a virtual image display device, a plurality of partial reflection surfaces arranged to be parallel to each other at a predetermined angle with respect to the main surface of the light guide plate while guiding image light using total reflection. There is known a technique in which image light is reflected and taken out from a light guide plate to allow the image light to reach an observer's retina (see Patent Document 1). Also, as a similar technique, in order to extract image light, a sawtooth portion is provided adjacent to the back surface opposite to the front surface from which image light is extracted, and the angle of the image light is changed in the sawtooth portion. There is also known one that forms a reflective layer for the purpose (see Patent Document 2).

Special table 2003-536102 gazette JP 2004-157520 A

  However, in the light guide plate used in Patent Documents 1 and 2, for example, a part of the image light is taken out in the direction of the eye after passing through the plurality of partial reflection surfaces a plurality of times, so that the position along the direction in which the image light is guided Differences in the number of reflections occur, and uneven brightness tends to occur. In particular, when the number of times of passage through the partial reflection surface increases, brightness unevenness becomes remarkable and light quantity loss may increase.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a virtual image display device capable of taking out image light in a good state while preventing image deterioration due to brightness unevenness while suppressing light amount loss.

  In order to solve the above-described problems, a first virtual image display device according to the present invention includes (a) an image forming apparatus that forms image light, and (b1) a light incident that takes in image light formed by the image forming apparatus. And (b2) a light guide unit that has first and second total reflection surfaces extending opposite to each other and guides image light taken from the light incident unit by total reflection on the first and second total reflection surfaces And (b3) an angle at which image light having a plurality of reflection surfaces arranged in a predetermined arrangement direction and incident through the light guide is converted by the reflection by the plurality of reflection surfaces and taken out to the outside. A virtual image display device comprising: a conversion unit; and (b4) a light guide plate that includes (b4) a light emission unit that emits image light that has passed through the angle conversion unit to the outside, and (c) the angle conversion unit includes: With respect to a predetermined arrangement direction of a plurality of reflecting surfaces, the basic horizontal width corresponding to the set horizontal angle of view is set by the observer. Has twice less width of the pupil effect partial modification width obtained is increased by at least the influence of magnitude, of the pupil of the size and motion. Here, the predetermined arrangement direction means a direction in which a plurality of reflection surfaces are arranged, for example, a direction perpendicular to the longitudinal direction when elongated reflection surfaces are arranged adjacent to each other in the longitudinal direction. Further, the set horizontal angle of view refers to an angle of view set corresponding to the horizontal direction for the observer due to the specifications of the virtual image display device. The size of the pupil means the size of the iris. The iris adjusts the light entering the retina by adjusting the size of the pupil located in front of the lens. In the above description, “horizontal” refers to a direction determined in relation to the predetermined arrangement direction, and does not necessarily match the horizontal and vertical directions with respect to the observer.

  In the virtual image display device, the angle conversion unit corrects the pupil influence by correcting the basic horizontal width corresponding to the horizontal angle of view at least by the influence of the pupil size with respect to a predetermined arrangement direction of the plurality of reflecting surfaces. It has a width less than twice the width. In this case, an upper limit size is set for the angle conversion unit while ensuring the necessary conditions for capturing an image into the eye in consideration of the horizontal angle of view and the size of the pupil with respect to the predetermined arrangement direction. By doing so, it is possible to suppress an excessive light amount loss of the image light in the angle conversion unit, prevent deterioration of the image due to occurrence of uneven brightness and the like, and extract the image light in a good state. In addition, by setting the upper limit size to a width that is twice or less, there are various uses such as when there are individual differences in the observer's eyes and their movements, or when the wearing state of the virtual image display device is deviated. It becomes possible to respond to the situation.

の式で与えられる。この場合、角度変換部の上記所定の配列方向に関する幅に上限サイズを設けることで、明るさムラ等の発生による画像の劣化を防ぐことができ、かつ、下限サイズを設けることで、画像を取り込むのに十分な幅を有するものにして画像欠けの発生を防止することができる。 In a specific aspect of the present invention, the width of the angle conversion unit in a predetermined arrangement direction is a coefficient k of 1 or more and 2 or less, the standard value of the size of the observer's pupil is A, and the observation is performed from the angle conversion unit. The distance to the person's eyes is S, and the horizontal half angle of view, which is half the horizontal angle of view, is θ.

Is given by In this case, by providing an upper limit size for the width of the angle conversion unit in the predetermined arrangement direction, it is possible to prevent image deterioration due to occurrence of brightness unevenness and the like, and by providing a lower limit size, an image is captured. Therefore, it is possible to prevent the occurrence of missing images by making the width sufficiently large.

  In still another aspect of the present invention, the width of the angle conversion unit in the predetermined arrangement direction is tan θ of the horizontal half angle of view θ that is a half value of the horizontal angle of view with respect to the distance from the angle conversion unit to the eyes of the observer. Is a value equal to or less than a value obtained by adding the maximum value of the size of the observer's pupil and the maximum value of the amount of movement of the eye of the observer to the value multiplied by 2 and multiplied. In this case, by limiting the width of the angle conversion unit in the predetermined arrangement direction to the minimum necessary, it is possible to reliably suppress the occurrence of brightness unevenness due to excessive increase in the width. Note that by adding the size of the observer's pupil and the amount of eye movement, it is possible to prevent image loss even if there are individual differences in the observer's eyes and their movement.

  In still another aspect of the present invention, the angle conversion unit includes, as a plurality of reflection surfaces, one set of a first reflection surface portion and a second reflection surface portion that forms a predetermined angle with respect to the first reflection surface portion. A plurality of reflection units, each of which reflects image light incident through the light guide portion by the first reflection surface portion and is reflected by the first reflection surface portion by the second reflection surface portion. The reflected image light is further reflected and taken out to the outside. In this case, the image light can be extracted by two-stage reflection between the first reflecting surface portion and the second reflecting surface portion.

  In still another aspect of the present invention, the width of the angle conversion unit in the predetermined arrangement direction is 20 mm or more when the horizontal angle of view is 35 ° or more. In this case, an image with a high angle of view can be formed.

  In order to solve the above-described problems, a second virtual image display device according to the present invention includes (a) an image forming apparatus that forms image light, and (b1) a light incident that captures image light formed by the image forming apparatus. And (b2) a light guide unit that has first and second total reflection surfaces extending opposite to each other and guides image light taken from the light incident unit by total reflection on the first and second total reflection surfaces And (b3) an angle at which image light having a plurality of reflection surfaces arranged in a predetermined arrangement direction and incident through the light guide is converted by the reflection by the plurality of reflection surfaces and taken out to the outside. A virtual image display device comprising: a conversion unit; and (b4) a light guide plate that includes (b4) a light emission unit that emits image light that has passed through the angle conversion unit to the outside, and (c) the angle conversion unit includes: The light incident side on the light guide plate with respect to the optical axis of the luminous flux of the image light emitted from the light emitting portion and entering the pupil of the observer In this case, the product of the distance from the angle conversion unit to the observer's eyes and the tan θ of the horizontal half angle of view θ that is a half value of the set horizontal angle of view is the size of the pupil of the observer observing the image light. And a width equal to or smaller than a value obtained by adding the maximum value of the height and the maximum value of the movement amount of the eye of the observer.

の関係を満たしていればよい。 In the virtual image display device, the angle conversion unit includes a distance from the angle conversion unit to the observer's eyes and a horizontal half on the light incident side of the light guide plate with respect to the light beam optical axis of the image light incident on the observer's pupil. It has a width equal to or smaller than the width obtained by adding the maximum value of the size of the observer's pupil and the maximum value of the amount of movement of the viewer's eyes to the product of the tangent of the angle of view. In this case, with respect to the light incident side portion of the light guide plate in the angle conversion unit, the upper limit size is ensured while ensuring the necessary conditions for capturing an image into the eye in consideration of the horizontal angle of view, the size of the pupil, etc. By suppressing the excessive light amount loss of the image light in the angle conversion unit, it is possible to prevent deterioration of the image due to occurrence of brightness unevenness and the like, and to extract the image light in a good state. Further, by adding the maximum size of the observer's pupil size and the amount of eye movement, it is possible to prevent image loss even if there are individual differences in the eyes and movement of the observer. In this case, the distance from the angle conversion unit to the observer's eyes is S, the horizontal half angle of view is θ, and the maximum width of the observer's pupil that observes the image light is A _max. The maximum value of the amount of eye movement of the observer is B _max , and the width Lm of the angle conversion unit on the light incident side from the light beam optical axis of the image light on the light guide plate is

As long as the relationship is satisfied.

(A) is sectional drawing which shows the virtual image display apparatus which concerns on 1st Embodiment, (B) and (C) are the front views and top views of a light-guide plate. (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 a figure for demonstrating the horizontal width of an angle conversion part, (B) and (C) are figures shown about the eye of the state which moved to the maximum. (A) is a figure explaining the virtual image display apparatus which concerns on 2nd Embodiment, and is a figure which shows the mode of reflection in the back | inner side of an angle conversion part, (B) is the entrance side of an angle conversion part. It is a figure which shows the mode of reflection of.

[First Embodiment]
The virtual image display device according to the first embodiment of the present invention will be described below.

[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.

  The image forming apparatus 10 includes a liquid crystal device 11 that is an image display element, and a collimating lens 12 for forming a light beam. The liquid crystal device 11 spatially modulates illumination light from a light source (not shown) to form image light to be a display target such as a moving image. The collimating lens 12 converts the image light emitted from each point on the liquid crystal device 11 into a light beam in a parallel state. The lens material of the collimating lens 12 can be either glass or plastic.

  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 arranged in an inclined state with respect to the light incident surface IS by cooperating with the inclined surface RS. Further, in the light guide plate main body 20a, an angle conversion unit 23 having a fine structure is formed along a plane on the back side of the light exit surface OS.

  The incident light bending portion 21 as the mirror layer 21a disposed to be inclined and opposed to the light incident surface IS of the light guide plate main body portion 20a is formed by depositing aluminum vapor deposition or the like on the inclined surface RS of the light guide plate main body portion 20a. It is formed by applying, and functions as a reflection surface for reflecting incident light and bending the optical path in a predetermined direction close to a substantially orthogonal direction. That is, the incident light bending portion 21 guides the image light by bending the image light incident from the light incident surface IS and traveling in the −X direction as a whole so as to be directed in the + Z direction biased in the + X direction as a whole. It couple | bonds reliably in the optical plate main-body part 20a.

  In addition, the light guide plate main body 20 a receives image light incident on the inside through the incident light bending portion 21 from the incident light bending portion 21 on the entrance side to the angle conversion portion 23 on the back side. It has a light guide 22 for guiding.

  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.

  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.

  Since the light guide plate 20 has the above-described structure, 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 by the incident light bending portion 21 and bent. The first and second total reflection surfaces 22a and 22b of the light guide unit 22 are repeatedly totally reflected and travel in a state of having a certain spread substantially along the optical axis OA. By being bent at an angle, it can be taken out and finally emitted from the light exit surface OS. The image light emitted to the outside 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)
Hereinafter, the optical path of the image light 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 liquid crystal device 11 is referred to as image light GL1. The component emitted from the right side (-Z side) of the drawing surface 11a indicated by the middle one-dot chain line 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. Let the component emitted from the image light GL3. In the drawing, the side where the prism PS having the light incident surface IS on which the image light is incident (the right side in FIG. 1A) in the Z direction of the light guide plate 20 is called the light incident side. The side on which no is arranged (the left side in FIG. 1A) is called the anti-light incident side.

The main components of the image lights GL1, GL2, and GL3 that have passed through the collimating lens 12 are all incident at different angles on the first and second total reflection surfaces 22a and 22b after entering from the light incident surface IS of the light guide plate 20, respectively. Repeat 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 liquid crystal device 11 is reflected by the incident light bending portion 21 as a parallel light flux, and then is standardized. The light enters the second total reflection surface 22b of the light guide unit 22 at the 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 as a parallel light flux from the light exit surface OS to the optical axis AX direction that is a light flux optical axis perpendicular to the YZ plane including the light exit surface OS. The The image light GL2 emitted from one end side (−Z side) of the emission surface 11a of the liquid crystal device 11 crosses the image light GL1 in the collimator lens 12 and enters the + Z side of the light incident surface IS as a parallel light beam and enters the incident light. After being reflected by the bent portion 21, it is incident on the second total reflection surface 22 b of the light guide portion 22 at the maximum reflection angle γ ₊ and is 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 is predetermined in the peripheral portion 23h on the back side (+ Z side) of the angle conversion unit 23. 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 liquid crystal device 11 crosses the image light GL1 in the collimator lens 12 and enters the -Z side of the light incident surface IS as a parallel light flux. After being reflected by the light bent portion 21, the light is incident on the second total reflection surface 22 b of the light guide portion 22 at the minimum reflection angle γ ₋ and is 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 at the peripheral portion 23m on the entrance side (−Z side) of the angle conversion unit 23, The light exits from the light exit surface OS in a predetermined angular direction as a parallel light flux. 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. In addition, since the reflection efficiency of light by the total reflection at the first and second total reflection surfaces 22a and 22b is very high, the number of reflections differs between the image lights GL1, GL2, and GL3 as described above. However, this hardly causes luminance unevenness, and does not feel the influence of image unevenness or the like on visual recognition. Further, the image light GL1, GL2, and GL3 are described on behalf of a part of the entire light beam of the image light. However, light beam components constituting other image light are guided in the same manner as the image light GL1 and the like. Since these are emitted from the light exit surface OS, illustration and description thereof are omitted.

Here, the reflection angle γ ₊ of the image light GL2 has a maximum value in the light guide plate 20 specification, and the reflection angle γ ₋ of the image light GL3 has a minimum value in the light guide plate 20 specification. Therefore, the total reflection angle of propagation of other effective image light within the light guide plate 20 is a value between these reflection angles γ ₊ and γ ₋ . The difference between the reflection angle range, that is, the maximum reflection angle γ ₊ and the minimum reflection angle γ ₋ corresponds to the horizontal angle of view on the optical design on the image forming apparatus 10 side, that is, the angle of view in the Z direction. ing. The image lights GL2 and GL3 are slightly refracted when passing through the light exit surface OS, but are oppositely refracted when passing through the light incident surface IS. However, the influence of the refractive action as a whole is substantially cancelled.

As an example of the value of the refractive index n of the transparent resin material used for the incident light bending portion 21 and the light guide portion 22, when n = 1.5, the value of the critical angle γ _c is γ _c ≈41.8 °. When n = 1.6, the critical angle γ _{c has} a value of γ _c ≈38.7 °. The minimum reflection angle γ ₋ of the reflection angles γ ₀ , γ ₊ , γ ₋ of each of the image lights GL1, GL2, and GL3 is set to a value larger than the critical angle γ _c , thereby guiding the necessary image light. The total reflection condition in the portion 22 can be satisfied.

[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. Here, the direction in which these reflection units 23c are arranged, that is, the Z direction is taken as the arrangement direction. Each reflecting unit 23c is a first reflecting surface 23a that is one reflecting surface portion disposed on the back side, that is, the light incident side, and another one reflecting surface portion that is disposed on the entrance side, that is, the light incident 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. More specifically, the first and second reflection surfaces 23a and 23b are parallel to the first total reflection surface 22a shown in FIG. 1A and the like and are arranged in the Z direction in which the reflection units 23c are arranged. A direction extending perpendicularly to the longitudinal direction, that is, the Y direction, is linearly extended. Further, 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 with the longitudinal direction as an axis. Yes. As a result, the first reflecting surfaces 23a are periodically and repeatedly arranged and extend in parallel with each other, and the second reflecting surfaces 23b are also periodically and repeatedly arranged and extend in parallel with each other. In the specific example shown in FIG. 2A and the like, each first reflection surface 23a is assumed to extend along a direction (X direction) substantially perpendicular to the first total reflection surface 22a. Each second reflecting surface 23b extends in a direction that forms a predetermined angle (relative angle) α counterclockwise with respect to the corresponding first reflecting surface 23a. 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, the bending of the optical path of the image light by the angle conversion unit 23 will be described in detail. 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 or more reflection units 23c arranged in the peripheral portion 23h on the + Z side farthest from (see FIG. 1A). In the reflection unit 23c, the image light GL2 is first reflected by the first reflection surface 23a on the back side, that is, the + Z side, and then reflected by the second reflection 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. The light is incident on one or more reflecting units 23c arranged in the peripheral portion 23m on the -Z side closest to (see A). In the reflection unit 23c, as in the case of the image light GL2, the image light GL3 is first reflected by the first reflection surface 23a on the back side, that is, the + Z side, and then the second light on the entrance side, that is, the −Z side. Is reflected by the reflecting surface 23b. The image light GL3 that has passed through the reflection unit 23c is bent to a desired angle by one pass through the angle conversion unit 23 without passing through the other reflection unit 23c, and is taken out to the viewer side.

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 FIG. 2, the direction when each image light is incident and the direction when it is emitted The bending angle ψ which is an angle formed 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. That is, the image light is emitted to the eye EY in a symmetric state about the optical axis AX. Here, as described above, the angle of the bending angle ψ in the angle conversion unit 23 is the same for all image lights. Therefore, the angle conversion unit 23, without affecting the magnitude of the lateral angle of the magnitude of the angle a combination of the angle theta ₂ and theta ₃ of the image light GL3 of the image light GL2 or image light entering the eye EY The difference between the maximum reflection angle γ ₊ and the minimum reflection angle γ _−, that is, the horizontal angle of view of the image light determined by the optical design on the image forming apparatus 10 side in FIG. the angle theta ₂ and the angle theta ₃ becomes to be reflected as the transverse angle of the image light by that.

  As already described, the first reflecting surface 23a or the second reflecting surface 23b constituting the group of reflecting units 23c have a constant pitch and are parallel to each other. Thereby, the image light which is the virtual image light incident on the eye EY of the observer can be made uniform, and the deterioration of the quality of the observed image can be suppressed. A specific numerical range of the pitch PT that is an interval between the reflection units 23c constituting the angle conversion unit 23 is 0.2 mm or more, and more preferably 0.2 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. Optical specifications of angle conversion unit)
Hereinafter, referring to FIG. 3A, the optical specification of the angle conversion unit 23, specifically, the conversion unit width that is the specific width of the entire reflection unit 23c of the angle conversion unit 23 with respect to the arrangement direction of the reflection units 23c. The relationship between L and the numerical value related to this will be described in detail.

で表される。ここで、観察者の眼ＥＹの瞳ＰＵの大きさ即ち虹彩の大きさは、Ｚ方向についてある程度の幅を有する。ここでは、人種等による違いを考慮して、瞳ＰＵのＺ方向の大きさについては、最大の幅Ａ_ｍａｘをとるものとする。また、眼ＥＹは、矢印ＡＲに示すように動く結果、最大限で図３（Ｂ）や図３（Ｃ）に示す状態となり得る。従って、角度変換部２３が実際に有する変換部幅Ｌは、上記基準横幅Ｌ_０に対して、幅Ａ_ｍａｘと、瞳ＰＵの動く量即ち眼ＥＹの動き量の最大値Ｂｍ，Ｂｈの合計である幅Ｂ_ｍａｘとを加算したものとする。つまり、これらの幅Ａ_ｍａｘ，Ｂ_ｍａｘによる影響分だけ加味するように必須の幅である基準横幅Ｌ_０を増加させた値を角度変換部２３の具体的な変換部幅Ｌとする。従って、変換部幅Ｌは、

で表される。この場合、角度変換部２３は、幅Ｌについて、基準横幅Ｌ_０を確保することで、画像を確実に取り込むのに最低限必要な幅を有する状態即ちＺ方向について光軸ＡＸに垂直な方向から観た画像に実質的な画像欠けのない状態にできる。さらに、瞳ＰＵの大きさや動きについて最大値である幅Ａ_ｍａｘ，Ｂ_ｍａｘを加算することで、眼ＥＹのサイズ等に個人差があっても実質的な画像欠けや減光を生じさせないものにできる。一方、幅Ｌに余剰な長さを持たせず必要最小限とすることで、角度変換部２３において意図しない画像光の角度変換を回避し明るさムラ等の発生による画像の劣化を防ぐことができるものとなっている。なお、この場合、画像光の有効成分が角度変換部２３において１回だけ反射するという条件も確保している。 First, as described above, the difference between the maximum reflection angle γ ₊ and the minimum reflection angle γ ₋ shown in FIG. 1A or the like is the horizontal field angle of the image light emitted from the image forming apparatus 10 in the Z direction. (That is, a horizontal field angle that is an angle of view with respect to the Z direction that is the arrangement direction of the reflection units 23c). As a result, the image light is emitted with the sum of the angle θ ₂ and the angle θ ₃ as the maximum angle. Here, by assuming that the angle θ ₂ and the angle θ ₃ are equal and symmetrical with respect to the optical axis AX, the angle θ ₂ and the angle θ ₃ are set to horizontal values that are half the horizontal angle of view. Half angle of view. That is, the angle θ ₂ and the angle θ ₃ correspond to the horizontal half angle of view θ, and θ ₂ = θ ₃ = θ. The horizontal field angle is 2θ. In this case, as shown in FIG. 3A, the X direction from the reflected light exit surface AS, which is the back surface of the angle conversion unit 23, to the vertex PK, which is the point closest to the light guide plate 20 among the eyes EY of the observer. When the distance S is defined as the distance S, the reference width L, which is an essential basic width in relation to the distance S in order to secure an image having the horizontal half angle of view θ, is first determined in determining the conversion width L of the angle conversion section 23. ₀ is

It is represented by Here, the size of the pupil PU of the observer's eye EY, that is, the size of the iris, has a certain width in the Z direction. Here, in consideration of the difference due to race or the like, the maximum width A _max is assumed for the size of the pupil PU in the Z direction. Further, as a result of the movement of the eye EY as indicated by the arrow AR, the state shown in FIG. 3B or FIG. Accordingly, the conversion unit width L actually included in the angle conversion unit 23 is the sum of the width A _max and the maximum amount Bm, Bh of the movement amount of the pupil PU, that is, the movement amount of the eye EY, with respect to the reference lateral width L ₀ . It is assumed that a certain width B _max is added. That is, a value obtained by increasing the reference width L ₀ which is an essential width so as to take into account the influences of these widths A _max and B _max is set as a specific conversion portion width L of the angle conversion portion 23. Therefore, the conversion part width L is

It is represented by In this case, the angle conversion unit 23 secures the reference lateral width L ₀ for the width L, so that the angle conversion unit 23 has a minimum necessary width for reliably capturing an image, that is, from the direction perpendicular to the optical axis AX in the Z direction. The viewed image can be made substantially free of image defects. Further, by adding the _maximum widths A _max and B _max for the size and movement of the pupil PU, even if there are individual differences in the size of the eye EY, etc., no substantial image loss or dimming occurs. it can. On the other hand, the width L does not have an excessive length and is minimized so that the angle conversion unit 23 avoids unintended angle conversion of image light and prevents image deterioration due to occurrence of uneven brightness. It is possible. In this case, the condition that the effective component of the image light is reflected only once by the angle conversion unit 23 is also secured.

In the above equation (2), the width L is defined on the basis of the size of the pupil PU and the maximum value of the movement amount of the eye EY. If a sufficient width can be ensured so as not to occur, the value of the converter width L may be equal to or less than the value on the right side of the equation (2). For example, instead of the maximum width _Amax , the size of the pupil PU can be set to, for example, the standard iris size (standard value) of a general adult.

で表される。この場合、係数ｋを１以上２以下の範囲で適宜定めることにより、例えば図中点線で示す眼ＥＹの動き量即ち瞳ＰＵが動く量を加味して幅Ｌを規定することができ、観察者の眼ＥＹの瞳ＰＵが動く場合にも実質的な画像欠けを生じさせることなく画像を問題なく視認できるようにできる。また、観察者の眼ＥＹが特殊である場合にも対処することができる。さらに、虚像表示装置１００の装着状態が多少ずれた場合にも対処することができる。なお、ここで、上式中辺又は右辺のカッコ内に示す値、つまり基準横幅Ｌ_０に幅Ａを加算した値を、基準横幅Ｌ_０を修正した瞳影響分修正横幅とすると、幅Ｌは、観察者の瞳ＰＵの大きさ及び眼ＥＹの動きのうち少なくとも瞳ＰＵの大きさの影響分だけ増加させた瞳影響分修正横幅の２倍以下の範囲にあることになる。なお、より確実にマージンを確保する観点からは、眼ＥＹの標準的な動き量をＢとして、

とすることが望ましい。 For the range allowed for the conversion unit width L, for example, the standard value of the size of the pupil PU in the Z direction is set as the width A, and this is added to the reference lateral width L ₀ to take a value of 1 or more and 2 or less. It may be specified using a value obtained by multiplying k. Specifically, the width L is determined by the width A, the reference lateral width L ₀ and the coefficient k.

It is represented by In this case, by appropriately determining the coefficient k in the range of 1 or more and 2 or less, for example, the width L can be defined in consideration of the amount of movement of the eye EY, that is, the amount of movement of the pupil PU indicated by the dotted line in the figure. Even when the pupil PU of the eye EY moves, the image can be viewed without any problem without causing substantial image loss. In addition, it is possible to cope with the case where the observer's eye EY is special. Furthermore, it is possible to cope with a case where the mounting state of the virtual image display device 100 is slightly deviated. Here, values shown in the above equation edge or in parentheses on the right side, that is, the value obtained by adding the reference width L ₀ in the width A, when a pupil effect partial modifications width that fix reference width L _0, the width L Thus, the pupil influence amount is increased by at least the effect of the size of the pupil PU among the size of the observer's pupil PU and the movement of the eye EY. In addition, from the viewpoint of securing a margin more reliably, the standard amount of movement of the eye EY is set as B,

Is desirable.

Here, the conversion part width L that satisfies the condition of the above expression (2) can be considered to satisfy the condition of the above expression (3). That is, the range of the condition of the expression (3) is wider than that of the expression (2). Since A _{max on} the right side of equation (2) is the maximum value and is larger than the value of A on the right side of equation (3), which is a standard value, when coefficient k is 1, which is the minimum, right side of equation (3) Is smaller than the value on the right side of equation (2). However, in equation (3), if the coefficient k is 2, which is the maximum, even if the value of A _max + B _{max in} equation (2) is considered, the value on the right side of equation (3) is the right side of equation (2). It becomes more than the value of. That is, the coefficient k in which the right side of the expression (3) is equal to the right side of the expression (2) exists in the range of 1 to 2, and the condition of the expression (2) is included in the condition of the expression (3). It can be said. If k = 1 and A = 0, the expression (3) includes the right side of the expression (1).

  As described above, in the case of the present embodiment, the angle conversion unit 23 considers the horizontal angle of view, the size of the pupil, and the like, and the eye EY relates to the width L of the angle conversion unit 23 in the arrangement direction of the reflection units 23c. By providing the upper limit size while ensuring the necessary conditions for capturing images, it is possible to suppress excessive light loss of image light in the angle conversion unit 23 and prevent deterioration of the image due to occurrence of uneven brightness, etc. In this state, the image light can be taken out.

It is assumed that the maximum pupil size is about 7 mm and the maximum eye movement amount is about 4 mm. Considering this value, the widths A _max and B _max and the width L are determined as described above, so that even if there are individual differences among observers, substantial image omission and dimming can be prevented.

  In the above description, the horizontal half angle of view θ is set to θ = 17.5 °, for example, that is, the horizontal angle of view is set to 35 °. An image equivalent to forming a 62-inch image IM 5 m ahead can be viewed. In this case, the width L of the angle conversion unit 23 is about 20 mm. In addition, by setting the width L of the angle conversion unit 23 to 20 mm or more, it is possible to form a high angle of view image with a horizontal half angle of view θ = 17.5 ° or more.

  Further, as another aspect of the above embodiment, focusing on only the light incident side, ie, the −Z side, from the optical axis AX within the light guide plate 20 in the width of the angle conversion unit 23 in the arrangement direction of the reflection units 23c. The optical specifications of the angle conversion unit 23 can also be considered. That is, only the condition that the width Lm on the −Z side from the optical axis AX should satisfy in the angle conversion unit 23 in the drawing.

の関係が満たされていればよいものとできる。この関係が満たされていれば、少なくとも導光板２０の光入射側から導かれた画像光が角度変換部２３のうち光入射側の部分即ち入口側の周辺部２３ｍ付近で不要な通過をすることを回避でき、画像光の過度の光量ロスを抑制できるので、明るさムラ等の発生を防止できる。 Hereinafter, the above case will be considered. First, when there is symmetry about the optical axis AX as described above, the width Lm may be less than or equal to half the maximum width of the entire width L. That is, for example, referring to the right side of equation (2) above,

As long as the relationship is satisfied, it can be done. If this relationship is satisfied, at least the image light guided from the light incident side of the light guide plate 20 may pass unnecessarily in the light incident side portion of the angle conversion unit 23, that is, in the vicinity of the peripheral portion 23m on the entrance side. Can be avoided and excessive light loss of image light can be suppressed, so that occurrence of uneven brightness can be prevented.

  Further, when the angle conversion unit 23 is made longer, that is, wider in width while satisfying the above-described conditions, the angle conversion unit 23 can be extended to the light incident side, that is, the + Z side. Even in such a case, it is necessary to extend the angle conversion unit 23 within a range that satisfies other structural requirements such as ensuring that the image light is only reflected once. Is done.

としてもよい。 In addition, with respect to the width Lm described above, the pupil PU size and the amount of movement of the eye EY may not be halved with respect to the entire width L, and the maximum value may be adopted as it is when a sufficient margin is required. Good. That is, by replacing the values related to the size of the pupil PU and the amount of movement of the eye EY for the right side of the above equation (4), the condition of the width Lm is changed.

It is good.

[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 according to the present embodiment is a modification of the virtual image display device 100 according to the first embodiment, and only the angle conversion unit 123 and its periphery are shown, and description and illustration of other structures are omitted. . Further, the same reference numerals as those of the virtual image display device 100 of the first embodiment have the same functions unless otherwise described.

  Hereinafter, the detailed structure of the angle conversion part 123 which comprises the virtual image display apparatus 200 which concerns on this embodiment is demonstrated. As shown in FIG. 4A and the like, the angle conversion unit 123 includes a large number of image light reflection surfaces 123a, and each image light reflection surface 123a is in the Z direction in which the image light reflection surfaces 123a are arranged. It extends in the direction extending vertically, that is, in the Y direction. The multiple image light reflecting surfaces 123a are parallel to each other, have the same angle with respect to the first total reflecting surface 22a, respectively, and partially reflect the light components of the image light and reflect the rest. It has become. The image light reflecting surfaces 123a are connected by a boundary portion 123b that does not have a function as a reflecting surface or the like for extracting image light. As a result, the image light reflecting surfaces 123a are arranged periodically and repeatedly along the Z direction and extend in parallel with each other.

Hereinafter, the image light GLa and the image light GLb that enter the both ends of the angle conversion unit 123 among the components of the image light will be described with reference to FIGS. 4 (A) and 4 (B). The other optical path components are the same as those described above, and are not shown. As a premise, the image light including the image lights GLa and GLb is incident on the light guide plate 20 shown in FIGS. 1A and 1B from the light incident surface IS, reflected by the incident light bending portion 21, and entirely. As described above, the light guide unit 22 travels in the + Z direction biased in the + X direction, and is repeatedly guided by the first and second total reflection surfaces 22a and 22b of the light guide unit 22 to be transmitted to the angle conversion unit 123. It arrives. First, as shown in FIG. 4A, the image light GLa totally reflected by the first and second total reflection surfaces 22a and 22b of the light guide section 22 at the minimum reflection angle γ ₋ After passing N times (N is a natural number greater than 1), it reaches the peripheral part 23h on the back side (+ Z side) of the angle conversion part 123, which is a position where it can enter the eye EY of the observer, and is reflected at the peripheral part 23h. Accordingly, it emitted as a parallel light beam toward the eye EY from the light exit surface OS at an angle theta ₂ with respect to the central axis AX of the eye EY. The emission angle at this time is an obtuse angle with respect to the + Z axis.

On the other hand, as shown in FIG. 4B, the image light GLb totally reflected by the first and second total reflection surfaces 22a and 22b of the light guide unit 22 at the maximum reflection angle γ ₊ is the eye EY of the observer. reaches the peripheral portion 23m of the inlet side of the angle conversion unit 123 is a position that can be incident (-Z side) by reflection at the peripheral portion 23m, the light exit plane at an angle theta ₃ with respect to the central axis AX of the eye EY It is emitted as a parallel light beam from the OS toward the eye EY. The emission angle at this time is an acute angle with respect to the + Z axis.

Here, with respect to the magnitude of the angle θ ₂ of the image light GL ₂ and the angle θ ₃ of the image light GL ₃ , that is, the angle of the image light entering the eye EY, the maximum reflection angle γ ₊ and the minimum reflection angle γ _- the equivalent to the difference between. Here, it is assumed that the angle θ ₂ and the angle θ ₃ are equal and symmetrical with respect to the optical axis AX, and the angles θ ₂ and θ ₃ correspond to the horizontal half angle of view.

を満たしている。または、角度変換部１２３のうち光軸ＡＸから光入射側についての幅Ｌｍが、例えば上記（４）式や（５）式の

を満たしている。これにより、画像を取り込むのに十分な幅を有して実質的な画像欠けや減光を抑制することが可能となる。また、明るさムラ等の発生による画像の劣化を防ぐことも可能となる。 Here, also in the present embodiment, as in the case of the first embodiment, the angle conversion unit 123 satisfies a certain condition for the horizontal width, that is, the conversion unit width L with respect to the Z direction that is the arrangement direction of the image light reflection surfaces 123a. It has become a thing. For example, the width L is a reference width L ₀ that is an essential width in relation to the distance S in order to secure the horizontal half angle of view θ, and a width A _max that is the maximum value of the size of the pupil PU in the Z direction. And the total amount of movement of the eye EY in relation to the width _Bmax , the above formulas (2), (3), or (3) ′

Meet. Alternatively, the width Lm from the optical axis AX to the light incident side of the angle conversion unit 123 is, for example, the expression (4) or (5)

Meet. As a result, it is possible to suppress substantial image loss and dimming with a sufficient width for capturing an image. It is also possible to prevent image deterioration due to occurrence of brightness unevenness or the like.

  In the case of the present embodiment, among the remaining components after the image light GLa has been transmitted through the angle conversion unit 123 a plurality of times, the component reflected by the peripheral portion 23h is emitted from the light emission surface OS. On the other hand, in the image light GLb, the component reflected by the peripheral portion 23m of the angle conversion unit 123 is emitted from the light emission surface OS without passing through the angle conversion unit 123 a plurality of times. Therefore, by performing precise adjustment of the amount of reflected / transmitted light in the angle conversion unit 123, the projected virtual image light corresponds to the number of passes from the entrance side (−Z side) toward the back side (+ Z side). Therefore, the number of times image light passes through the peripheral portion 23m on the light incident side, that is, the entrance side (−Z side) of the angle conversion unit 123 must be suppressed. It is particularly important not to increase the value more than specified. Therefore, the position of the edge EG that is the end on the peripheral portion 23m side of the angle conversion unit 123 is set without being shifted according to the design of the image light GLa, GLb, etc., and unintentional image light does not pass through. I am doing so. 4A and 4B, the position of the edge EG is shifted to the −Z side from the position where it should be, and the excessive angle conversion portion EP exists at an unintended position. Assuming that it is in a state, there is a possibility that the image light GLa and GLb pass through the excessive angle conversion part EP, causing an unintended light amount loss and causing uneven brightness.

  In the case of the present embodiment, the number of times the image light passes is not increased by satisfying the above-described conditions regarding the lateral width of the angle conversion unit 123 and adjusting the position of the edge EG of the angle conversion unit 123. It is possible to suppress an excessive light amount loss of image light, prevent deterioration of the image due to occurrence of brightness unevenness and the like, and extract image light in a good state. Also in the present embodiment, when the angle conversion unit 123 is longer, that is, wider in width, the angle conversion unit 123 can be extended to the light incident side, that is, the + Z side. In the case of this embodiment, unlike the first embodiment, the condition that each image light is reflected only once by the angle conversion unit 23 is not imposed, but in general, the amount of light loss increases toward the anti-light incident side and becomes darker. Since it is easy, it can be extended to the reflected light incident side as long as it has a light quantity within the range allowed for the image.

[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, the transmissive liquid crystal device 11 is used as the image display element. However, the image display element is not limited to the transmissive liquid crystal device, and various 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 liquid crystal device 11. Moreover, the structure using the self-light-emitting element represented by LED array, OLED (organic EL), etc. 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 made 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 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 V-shaped groove formed by the reflection unit 23c is illustrated with the tip sharpened. However, the shape of the V-shaped groove is not limited to this, and the tip is cut flat. It may be one that has an R (roundness) at the tip.

  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.

DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus 11 ... Liquid crystal device 20, 120 ... Light guide plate, 20a ... Light guide plate main-body part, 21 ... Incident light bending part, 22 ... Light guide part, 22a, 22b ... Total reflection surface, 23,123 ... Angle converter, 23a, 23b ... Reflecting surface, 23c ... Reflecting unit, 100 ... Virtual image display device, IS ... Light entrance surface (light entrance portion), OS ... Light exit surface (light exit portion), EY ... Eye, PU ... pupil, PT ... pitch, RS ... slope, GL1, GL2, GL3 ... image light, S ... distance, θ ... horizontal half angle of view, 2θ ... horizontal angle of view, α ... angle, AX ... optical axis (light beam optical axis) , L: conversion section width, A, B, A _max , B _max ... width (pupil size, pupil movement amount), L ₀ ... reference lateral width, Lm ... width (light incident from optical axis AX of optical path conversion section) Side width), k ... coefficient, n ... refractive index

Claims (6)

An image forming apparatus for forming image light;
A light incident part for taking in the image light formed by the image forming apparatus; and first and second total reflection surfaces extending opposite to each other; and the image light taken in from the light incident part. A light guide part guided by total reflection at the first and second total reflection surfaces; and a plurality of reflection surfaces arranged in a predetermined arrangement direction, and the image light incident through the light guide part is reflected by the plurality of reflections. A light guide plate having an angle conversion unit that converts an angle by reflection on a surface and can be extracted and a light emission unit that emits the image light that has passed through the angle conversion unit;
A virtual image display device comprising:
The angle conversion unit calculates a basic horizontal width corresponding to a set horizontal angle of view with respect to the predetermined arrangement direction of the plurality of reflecting surfaces, and determines an influence of at least the pupil size among the size and movement of the observer's pupil. A virtual image display device having a width equal to or less than twice the lateral width corrected for pupil influence obtained by increasing the amount of A width of the angle conversion unit in the predetermined arrangement direction is a coefficient k of 1 or more and 2 or less, a standard value of the size of the pupil of the observer is A, and from the angle conversion unit to the eye of the observer And the horizontal half angle of view, which is half the horizontal angle of view, as θ,

The virtual image display device according to claim 1, which is given by:   The width of the angle conversion unit in the predetermined arrangement direction is 2 by multiplying the distance from the angle conversion unit to the eyes of the observer by tan θ of the horizontal half field angle θ that is a half value of the horizontal field angle. The virtual image display device according to claim 2, wherein the virtual image display device has a value equal to or less than a value obtained by adding a maximum value of a size of the observer's pupil and a maximum value of a movement amount of the eye of the observer to the multiplied value.   The angle conversion unit includes a plurality of reflections each having a first reflection surface portion and a second reflection surface portion forming a predetermined angle with respect to the first reflection surface portion as the plurality of reflection surfaces. Each of the reflection units reflects the image light incident through the light guide portion by the first reflection surface portion and is reflected by the first reflection surface portion by the second reflection surface portion. The virtual image display device according to any one of claims 1 to 3, wherein the image light is further reflected and extracted to the outside.   The virtual image according to any one of claims 1 to 4, wherein a width of the angle conversion unit in the predetermined arrangement direction is 20 mm or more when the horizontal angle of view is 35 ° or more. Display device. An image forming apparatus for forming image light;
A light incident part for taking in the image light formed by the image forming apparatus; and first and second total reflection surfaces extending opposite to each other; and the image light taken in from the light incident part. A light guide part guided by total reflection at the first and second total reflection surfaces; and a plurality of reflection surfaces arranged in a predetermined arrangement direction, and the image light incident through the light guide part is reflected by the plurality of reflections. A light guide plate having an angle conversion unit that converts an angle by reflection on a surface and can be extracted and a light emission unit that emits the image light that has passed through the angle conversion unit;
A virtual image display device comprising:
The angle conversion unit is configured so that, on the light incident side of the light guide plate with respect to the light beam optical axis of the image light emitted from the light emitting unit and entering the observer's pupil, the angle conversion unit and the observer's eyes Is the product of the tan θ of the horizontal half angle of view θ, which is a half value of the set horizontal angle of view, and the maximum value of the pupil size of the observer observing the image light and the eyes of the observer A virtual image display device having a width equal to or less than a value obtained by adding the maximum value of the movement amount.

Images