JP7076995B2 - Display device and head-mounted display - Google Patents

Description

The present invention relates to a display device and a head-mounted display, and more particularly to a display device using a light guide plate.

A display device using a light guide plate is a device that guides the light emitted from the display element to the observer's eyes by the light guide plate and displays an image in the observer's eyes.

Patent Document 1 describes a display device in which light from a display element is confined in a flat substrate, and the light is emitted to the outside by a plurality of extraction mirrors arranged in the flat substrate to display an image in the eyes of an observer. Is disclosed.

Patent Document 2 describes a display device in which light from a display element is confined in a flat substrate and the light is emitted to the outside by a plurality of extraction mirrors arranged under the flat substrate to display an image in the eyes of an observer. Is disclosed.

Patent Document 3 describes a display device in which light from a display element is confined in a flat substrate, and the light is emitted to the outside by a plurality of extraction mirrors arranged on the flat substrate to display an image in the eyes of an observer. Is disclosed.

It should be noted that Patent Document 4 discloses that a mirror having a plurality of regions having different reflectances increases the light flux width of each of the polarized light flux groups.

Special Table 2005-521099 Special Table 2010-533316 Gazette WO2015 / 07633A Special Table 2003-520984 Gazette

In Patent Document 1, since the extraction mirror is arranged from the upper surface to the lower surface in the flat substrate, the extraction mirror receives not only the light totally reflected by the lower surface of the flat substrate but also the light totally reflected by the upper surface of the flat substrate. There is a risk that ghosts will occur due to direct incident.

In Patent Documents 2 and 3, a plurality of extraction mirrors are used, but the light flux width of each of the deflection light flux groups deflected by the plurality of extraction mirrors becomes small, and a large gap is formed between the light flux and the light flux. It had been done. As a result, in the display devices of Patent Documents 2 and 3, the light amount distribution of the polarized luminous flux group becomes uneven, and a high-quality image cannot be displayed.

Therefore, an object of the present invention is to provide a display device capable of displaying a higher image quality image.

The display device as one aspect of the present invention is a display device including a light guide element and an incident optical system for incident light from the display element on the light guide element, and the light guide element is the incident optical. It has a first light guide unit that guides the light from the system in the first direction, and a second light guide unit that guides the light from the first light guide unit in a second direction that intersects the first direction. At least one of the first light guide unit and the second light guide unit is arranged along the first direction or the second direction with the incident surface on which the light is incident, and reflects the light. The mirror group has a mirror group and a reflecting surface facing the mirror group, and each of the mirror group has a plurality of mirrors including a region in which the light is partially reflected, and the plurality of mirrors are the first. It includes one mirror and a second mirror arranged between the first mirror and the incident surface , and the shortest distance between the reflecting surface and the first mirror is the shortest distance between the reflecting surface and the second mirror. It is characterized by being longer than the distance.

Other aspects of the invention will be demonstrated in embodiments described below.

According to the present invention, it is possible to provide a display device capable of displaying a higher image quality image.

It is a figure of the display device of Example 1 to which this invention can apply. It is a figure of the light guide plate of Example 1 to which this invention can apply. It is explanatory drawing of the horizontal light guide part of Example 1 to which this invention can apply. It is explanatory drawing of the horizontal mirror group of Example 1 to which this invention can apply. It is explanatory drawing of the vertical light guide part of Example 1 to which this invention can apply. It is explanatory drawing of the vertical take-out mirror of Example 1 to which this invention can apply. It is explanatory drawing of the horizontal mirror group of Example 1 to which this invention can apply. It is a figure of the display device of Example 2 to which this invention is applied. It is explanatory drawing of the horizontal light guide part of Example 2 to which this invention can apply. It is explanatory drawing of the vertical light guide part of Example 2 to which this invention can apply. It is a figure of the display device of Example 3 to which this invention can apply. It is a figure of the smart glass of Example 4 to which this invention can apply.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The display device of Example 1 to which the present invention can be applied will be described.

FIG. 1 shows a display device to which the present invention can be applied.

The display device 1 includes a light guide plate (light guide element) 2, an incident optical system 3, and a display element 4.

The divergent light flux radiated from the display element 4 is converted into a parallel light beam by the incident optical system 3 and coupled to the incident surface of the light guide plate 2, and the combined light flux propagates inside the light guide plate 2 and then propagates inside the light guide plate 2. It is ejected from the ejection surface of the above and is incident on the observer's eye 5. As described above, the display device 1 of the present embodiment displays an image (including an image) on the observer's eye 5 when the observer places the eye 5 at a predetermined position on the injection surface side of the light guide plate 2. It is a display device that can be used. As the display element 4, a transmissive liquid crystal display (LCD), a reflective liquid crystal display (LCOS), a digital mirror device (DMD), an organic electroluminescence (OLED), a spatial modulator (SLM), or the like can be used.

FIG. 2 shows the light guide plate of this embodiment.

The light guide plate 2 of this embodiment has a horizontal light guide unit 21 in which the light beam propagates inside the light guide plate in the horizontal direction (first direction) and a vertical light guide unit 22 in which the light beam propagates in the vertical direction (second direction). The horizontal light guide unit 21 has a horizontal propagation unit 211 and a horizontal mirror group 212, and the horizontal mirror group 212 is arranged under the horizontal propagation unit 211. Further, the vertical light guide unit 22 has a vertical propagation unit 221 and a vertical mirror group 222, and the vertical mirror group 222 is arranged on the side of the vertical propagation unit 221 where the observer's eye 5 is arranged. Then, the vertical propagation section 221 is arranged under the horizontal mirror group 212, and the horizontal light guide section 21 and the vertical light guide section 22 are connected to form the light guide plate 2.

3 (A) is a top view of the horizontal light guide unit, and FIGS. 3 (B) and 3 (C) are front views of the horizontal light guide unit.

In FIGS. 3A and 3B, the luminous flux passing through the center of the angle of view with respect to the observer's eye (the luminous flux emitted from the light guide plate in parallel with the X direction), that is, the luminous flux at the central angle of view is horizontal. The state of propagating in the light guide section was also shown.

The light flux propagation in the horizontal light guide section will be described with reference to FIGS. 3 (A) and 3 (B).

The horizontal light guide unit 21 includes a horizontal propagation unit 211 and a horizontal mirror group 212, and is configured by joining a part of the lower surface 2114 of the horizontal propagation unit 211 and the upper surface of the horizontal mirror group 212. A transmissive reflective film is arranged between the joint surface, that is, between the horizontal propagation portion 211 and the horizontal mirror group 212, through which a part of the incident light flux is transmitted and a part of the light beam is reflected.

The horizontal propagation portion 211 is a cube having a front surface 2111, a back surface 2112, an upper surface 2113, a lower surface 2114, a left surface 2115, and a right surface 2116, and the length L is the largest when the length L, the height H, and the width W are set. Next, the height H is the largest and the width W is the smallest. The horizontal propagation portion 211 is a cube whose length is long in the horizontal direction (Z-axis direction), and the upper surface 2113 is arranged so as to face the Y direction in which the vertical light guide portion 22 is arranged. Further, the horizontal mirror group 212 is arranged so as to face the upper surface 2113 (first reflecting surface) of the horizontal propagation portion.

The left surface 2115 of the horizontal gene transfer portion is used as an incident surface, and a light flux from an incident optical system (not shown) is incident from the incident surface. Further, the region of the lower surface 2114 (first emission surface) of the horizontal propagation portion that is joined to the horizontal mirror group 212 is set as the emission region, and the light that has passed through at least a part of the horizontal propagation portion is emitted from the emission region. .. Of the incident luminous flux, the luminous flux at the center angle propagates flatly at four angles of ± 26 ° in the XZ cross-sectional direction and ± 32 ° in the YZ cross-sectional direction with respect to the longitudinal axis (major axis) Ax of the horizontal propagation portion 211. It is incident inside the section 211 and becomes a propagating luminous flux inside the horizontal light guide section 21. The reason why the luminous flux at the central angle of view has positive and negative inclinations in the XZ cross-sectional direction and the YZ cross-sectional direction, respectively, and is incident at four angles is as follows using FIGS. 9 (A) and 9 (B) of Example 2. It will be described in detail later. Here, a brief explanation will be given. The connecting portion 32 of the incident optical system 3 connected to the horizontal light guide portion is provided with a flat surface portion (not shown) parallel to the back surface 2112 and the upper surface 2113, respectively. Since a light beam that is internally reflected on the flat surface portion and is incident on the horizontal light guide portion and a light beam that is not internally reflected on the flat surface portion and is incident on the horizontal light guide portion are generated in each of the XZ cross-sectional direction and the YZ cross-sectional direction. It will be incident at four angles. In this embodiment, the incident optical system and the horizontal light guide unit 21 are made of the same material, and even inside the horizontal light guide unit 21, the propagating luminous flux is ± 26 ° in the XZ cross-sectional direction with respect to the long axis Ax and in the YZ cross-sectional direction. It has an angle of ± 32 °. At this time, the angles formed by the propagating luminous flux with respect to the long axis Ax are referred to as XZ propagating angle and YZ propagating angle, respectively, in the XZ cross-sectional direction and the YZ cross-sectional direction.

In FIG. 3A, the propagating light fluxes 511 and 513 are light fluxes having an XZ propagation angle of +26 °, the propagating light fluxs 512 and 514 are light fluxes having an XZ propagation angle of −26 °, and the propagating light fluxes are the front surface 2111. Total internal reflection is repeated on the back surface 2112 to reach the right surface 2116.

In FIG. 3B, the propagating light fluxes 511 and 512 are light fluxes having a YZ propagation angle of + 32 °, the propagating light fluxes 513 and 514 are light fluxes having an XZ propagation angle of −32 °, and the propagating propagating light fluxes are the upper surface 2113. Total internal reflection is repeated at, and reflection is repeated at the lower surface 2114 to reach the right surface 2116.

In this way, the propagating light beam of all angles of view including the light beam of the central angle of view propagates at an angle in the two-dimensional direction (XZ cross-sectional direction and YZ cross-sectional direction) in the horizontal propagating portion 211, and is propagating light beam. Is configured to propagate spirally in the horizontal propagation portion 211.

The propagating light beam propagates horizontally to the right surface 2116 while repeating internal reflection on four surfaces (front surface 2111, back surface 2112, upper surface 2113, lower surface 2114) parallel to the horizontal direction of the horizontal propagation portion 211. The propagating luminous flux that reaches the lower surface 2114 of the horizontal propagating portion is partially reflected and partially transmitted by the transmissive reflection film provided on the joint surface, and the transmitted propagating light flux is incident on the horizontal mirror group 212. In the horizontal mirror group 212, a plurality of horizontal extraction mirrors 2120 having an inclination in the YZ cross section are arranged side by side in the Z-axis direction, and the propagating light beam incident on the horizontal mirror group 212 is reflected by the horizontal extraction mirror 2120. It is deflected in the Y-axis direction and incident on the vertical light guide.

As described above, in this embodiment, the propagation angle has a plus direction and a minus direction in each of the XZ cross-section direction and the YZ cross-section direction for one angle of view, and there are a total of four directions. By arranging in this way, the inside of the horizontal propagating portion 211 can be filled with the propagating light flux, and the light amount distribution of the light flux incident on the observer's eye can be made uniform regardless of the position of the horizontal propagating portion 211 where the propagating light flux is taken out. can do.

Although not shown, with respect to the propagation angle inside the horizontal light guide unit 21, each angle of view light flux has 0 ° to ± 7.7 ° in the XZ cross-sectional direction and 0 ° to ± in the YZ cross-sectional direction with respect to the central angle of view light flux, respectively. It has an angle of 13.5 °. When a light guide plate with a refractive index of N = 1.4 or more and 2.0 or less is ejected into an air layer having a refractive index of N = 1.0 and is incident on the observer's eyes, the angle of view is increased in order to refract at the ejection surface. Is greater than the propagation angle. Since the XZ cross-sectional direction is vertical, the XZ propagation angle is converted to a vertical angle of view from 0 ° to ± 11.6 °, and because the YZ cross-sectional direction is horizontal, the YZ propagation angle is converted to a horizontal angle of view and is 0 ° to ± It is a display device with 20.0 °.

The propagation angle ω in the horizontal propagation portion and the incident angle Ψ on the side surfaces (upper surface, lower surface, front surface, and back surface) of the horizontal propagation portion have a relationship of ω = 90 ° −Ψ. If the propagation angle of the propagating luminous flux in the horizontal propagating portion is set large, a situation may occur in which the light is transmitted on the side surface of the horizontal propagating portion without total reflection depending on the refractive index of the material of the horizontal propagating portion. For example, when the material of the horizontal gene transfer part is synthetic quartz (Nd = 1.45857), the critical angle is 43.28 °, and the horizontal gene transfer angle is ω = 90 ° -43.28 ° = 46.72 ° or more. It penetrates the side surface of the propagation part.

In this embodiment, the propagation is performed in the two-dimensional direction in the horizontal propagation portion, and the incident angle to the side surface of the horizontal propagation portion is larger than that in the case where the incident angle of the composition in the two-dimensional direction is propagated in the one-dimensional direction. can do. The propagation angle ω in the horizontal propagation portion should be within the range of the conditional expression (1).
10 ° ≤ ω ≤ 50 ° ... Conditional expression (1)

When the upper limit is exceeded, the angle of incidence on the side surface of the horizontal gene transfer portion falls below the critical angle depending on the material. Below the lower limit, many voids are generated in the deflection luminous flux group reflected by the horizontal mirror group 212. The latter will be described in detail later with reference to FIG.

In this embodiment, the propagation angle (XZ propagation angle ωxz) in the XZ cross-sectional direction is set to + 18.3 ° to + 33.7 ° and -18.3 ° to -33.7 ° in the horizontal propagation section, and is in the YZ cross-sectional direction. The propagation angle (YZ propagation angle ωyz) was set to + 18.5 ° to + 44.5 ° and -18.5 ° to -44.5 °. In addition, set the XZ propagation angle in the one-dimensional direction or the YZ propagation angle in the one-dimensional direction to "90 ° -critical angle" or more within the range where the propagation angle ω in the two-dimensional direction is less than "90 ° -critical angle". It is also possible to propagate a light beam with a wide angle of view while reducing the amount of light loss.

FIG. 3C shows the propagation of the angle-of-view ray.

Each angle of view luminous flux will be described with reference to FIG. 3 (C).

The angle of view light flux 511 in FIG. 3C propagates in the horizontal propagation section 211 at a YZ propagation angle of + 32 °, the angle of view light flux 523 at a YZ propagation angle of −45 °, and the angle of view light flux 533 at a YZ propagation angle of -19 °. ing. The propagating luminous flux at each angle of view has a propagating angle in the plus direction and a propagating angle in the minus direction, and one of them is shown in FIG. 3C.

The propagating luminous flux 511, 523, and 533 propagate while repeating internal reflection (total reflection) on the upper surface, the lower surface, the front surface, and the back surface of the horizontal propagation unit 211. When the propagating luminous flux reaches the lower surface 2114 coated with the transmitted reflective film, a part of the propagating light flux passes through the lower surface 2114 and enters the horizontal mirror group 212, and the other part is reflected by the lower surface 2114 and is reflected in the horizontal propagating portion. Propagate within 211.

A plurality of extraction mirrors 2120 having an inclination in the YZ cross section are arranged in the horizontal mirror group 212, and the light incident on the horizontal mirror group 212 is reflected by the extraction mirror 2120 to deflect the propagation angle in the YZ cross section direction. , It passes through the lower surface of the horizontal mirror group 212 and is incident on the vertical light guide portion.

At this time, by arranging the horizontal mirror group 212 on the vertical light guide unit 22 side of the horizontal propagation unit 211, the number of reflections when propagating in the horizontal propagation unit 211 can be reduced, and the light amount loss can be reduced.

This will be explained in detail. When the observer looks straight ahead, the light beam emitted from the center of the vertical light guide portion 22 of the light guide plate in the horizontal direction (Z-axis direction) reaches the observer's eyes to display the image. When the observer looks to the left, the luminous flux emitted from the left side of the vertical light guide unit 22 reaches the observer's eyes, and when the observer looks to the right, the light flux emitted from the right side of the vertical light guide unit 22 reaches the observer's eyes. By displaying the image. The angle of view light flux 511 in FIG. 3C has a YZ propagation angle of + 32 °, and the light flux reflected by the horizontal mirror group 212 goes straight down in the YZ cross section and corresponds to a light flux traveling in the center of the angle of view with respect to the eye. .. The angle of view light flux 523 has a YZ propagation angle −45 °, and the light flux reflected by the horizontal mirror group 212 travels in the lower right direction in the YZ cross section and corresponds to a light flux traveling in the left direction of the angle of view with respect to the eye. The angle of view light flux 533 has a YZ propagation angle of -19 °, and the light flux reflected by the horizontal mirror group 212 travels in the lower left direction in the YZ cross section and corresponds to a light flux traveling in the right direction of the angle of view with respect to the eye. Therefore, the angle of view luminous flux 511 becomes an effective luminous flux that enters the observer's eyes when emitted from the vicinity of the center of the horizontal mirror group 212. The angle of view luminous flux 523 is emitted from the left side of the horizontal mirror group 212 (left side 2115 side of the horizontal propagation portion), and the angle of view luminous flux 533 is emitted from the right side of the horizontal mirror group 212 (right surface 2116 side of the horizontal propagation portion) to the observer's eyes. It becomes the effective luminous flux that enters. As described above, the larger the absolute value of the propagation angle is, the more effective the luminous flux is when ejected from the incident surface (left surface 2115) side of the horizontal propagation portion of the horizontal mirror group 212. When the absolute value of the propagation angle is large, the number of reflections inside the horizontal propagation unit 211 with respect to the propagation distance increases, and the number of reflections when propagating to a position where the effective luminous flux is obtained increases, causing a problem of light amount loss. In particular, a transmissive reflective film is installed on the joint surface between the lower surface 2114 of the horizontal propagation portion and the horizontal mirror group, and the reflectance at the joint surface (or the joint region of the lower surface 2114 of the horizontal propagation portion) is about 50%. If this is the case, the amount of light of the propagating light beam decreases according to the number of reflections. This means that the light amount of the propagating luminous flux decreases as the distance from the incident surface 2115 of the horizontal propagating portion increases, but in order to make the light amount distribution uniform at all angles of view, the light amount is adjusted to the place where the light amount is low. Loss becomes a problem.

When the horizontal mirror group 212 is arranged between the horizontal propagation section 211 and the vertical propagation section 221 as in this embodiment, the larger the absolute value of the propagation angle is, the more the incident surface side of the horizontal propagation section of the horizontal mirror group 212 is on the incident surface 2115 side. It can be configured to have an effective light beam when emitted from. As a result, the number of reflections in the horizontal gene transfer portion 211 can be reduced, so that the light amount loss can be reduced.

4 (A), 4 (C), and 4 (D) are explanatory views of the horizontal mirror group 212 in this embodiment, and FIG. 4 (B) is an explanatory diagram of the horizontal mirror group 212 of the comparative example.

The configurations of the plurality of extraction mirrors 2120 of the horizontal mirror group 212 in the present embodiment will be described with reference to FIGS. 4 (A) to 4 (D).

As the horizontal mirror group 212, 43 horizontal take-out mirrors 2120 are arranged in parallel with each other in the Z-axis direction. FIG. 4A schematically shows a part of the horizontal take-out mirror 2120. The normals of the 43 horizontal take-out mirrors 2120 are tilted 61 ° in the YZ direction in the plane including the Y direction and the Z direction. The horizontal extraction mirror 2120 is provided with two types of reflection regions 2121 and 2122 having different reflectances and transmittances. A half mirror having a reflectance of about 45% and a transmittance of about 45% and a reflectance-to-transmittance ratio of about 1: 1 is arranged in the first reflection region 2121 near the horizontal propagation portion of the horizontal take-out mirror 2120. There is. On the other hand, in the second reflection region 2122 far from the horizontal propagation portion of the horizontal extraction mirror 2120, a high reflection mirror having a reflectance of about 85% and a transmittance of 1% or less is arranged. That is, the upper half of the height (Y direction) of the horizontal take-out mirror 2120 was the half mirror 2121, and the lower half was the high reflection mirror 2122. As a result, of the luminous flux from the horizontal propagation portion 211, a part of the incident light flux to the half mirror 2121 is reflected and deflected toward the vertical light guide portion, and the other part of the incident light beam is transmitted to the next. It can be reflected by the high reflection mirror 2122 of the extraction mirror 2120 and deflected toward the vertical light guide unit. That is, when the horizontal extraction mirror 2120 has the first and second mirrors, the light transmitted through the first reflection region of the first mirror is reflected by the second reflection region of the second mirror and incident on the vertical light guide portion, and the second mirror is present. The light reflected in the second reflection region of the 1 mirror directly enters the vertical light guide portion without passing through the second mirror. At this time, the deflected luminous flux group deflected in the direction of the vertical light guide portion by the extraction mirror 2120 has a larger luminous flux width than the propagated luminous flux in the horizontal propagating portion 211. The luminous flux widths of the propagating light flux in the horizontal propagating portion 211 were Wp1, Wp2, and Wp3, but the widths of the deflected luminous flux group after being reflected by the horizontal extraction mirror 2120 are Wr1, Wr2, and Wr3. Wr1> Wp1, Wr2> Wp2, Wr3> Wp3, and the width of the light flux group after being reflected by the horizontal extraction mirror 2120 is always large, and the light flux width reaches the observer's eyes. Has the effect of expanding.

Further, a comparative example is shown in FIG. 4 (B). In the horizontal mirror group of the comparative example, unlike the configuration of the present embodiment, the entire area of the horizontal extraction mirror 2120 is a high reflection mirror. The deflected luminous flux group deflected by the horizontal extraction mirror is also expanded beyond the luminous flux width of the propagating luminous flux as in this embodiment, but many voids (parts where no luminous flux exists) are generated in the deflected luminous flux group, and the deflection occurs. The uniformity of the amount of light in the luminous flux group becomes a problem.

However, when the half mirror 2121 is arranged in a part of the horizontal extraction mirror 2120 as in the present embodiment, the half mirror 2121 separates the reflected light flux and the transmitted light flux, so that when the luminous flux width of the reflected light flux is expanded, the light flux width is expanded. The generated void can be filled with the transmitted luminous flux. Therefore, a high-reflection mirror is arranged on the vertical light guide portion side of the half mirror 2121, and the transmitted light beam of the half mirror 2121 is reflected by the high-reflection mirror 2122 of the adjacent horizontal extraction mirror 2120 to fill the above-mentioned gap. did.

In this way, by separating the luminous flux incident on the horizontal extraction mirror 2120 into two luminous fluxes and deflecting them toward the vertical light guide unit, the luminous flux width of the conventional deflected luminous flux group is expanded and expanded. It also has the effect of making the light amount distribution within the polarized luminous flux group uniform.

The propagating luminous flux totally reflected by the upper surface 2113 of the horizontal propagating portion reaches the horizontal extraction mirror 2120. The first reflection region of the horizontal take-out mirror 2120 is arranged on the upper surface 2113 side of the horizontal propagation portion from the second reflection region, that is, the first reflection region is arranged shorter than the second reflection region from the upper surface 2113 of the horizontal propagation portion. .. By adopting this configuration, it is possible to realize pupil enlargement and uniformity of the amount of light due to the polarized luminous flux group.

In the horizontal take-out mirror 2120 of this embodiment, the half mirror 2121 and the high reflection mirror 2122 are divided into upper and lower halves, and the arrangement ratio is set to 1: 1. However, the arrangement ratio is not limited to this, and the arrangement ratio is 2: 1. Or 3: 1, 4: 1, and so on. Furthermore, all may be half mirrors 2121. Compared to these, when the half mirror 2121 and the high reflection mirror 2122 are arranged 1: 1, the light transmitted through the half mirror 2121 is arranged between the reflected light rays of the half mirror 2121 and the light beam reflected by the high reflection mirror 2122 is arranged. Can be done. This configuration is suitable for expanding the luminous flux width, making the light amount distribution in the expanded luminous flux uniform, and improving the light utilization efficiency. Further, the half mirror 2121 is not limited to a reflectance of 45% and a transmittance of 45%, and may be an amplitude splitting mirror that splits the amplitude. For example, by setting the transmittance to 41% and the transmittance to be higher than the transmittance, the amount of light reflected by the half mirror and the luminous flux transmitted through the half mirror and reflected by the high reflection mirror are almost the same. It becomes possible to correct the light amount distribution in the luminous flux group more uniformly. Further, even if the ratio of the reflectance to the transmittance is 2: 1 or 1: 2, it can be used without any problem in practical use.

Further, among the horizontal extraction mirrors 2120, the last mirror (the mirror farthest from the incident surface 2115) has no mirror after that and has no effective portion. Therefore, both the first region 2121 and the second region 2122 are used as high reflection mirrors. The amount of polarized light is increased.

Further, the distance between the plurality of horizontal extraction mirrors 2120 is preferably smaller than the pupil diameter of 4 mm of the eye 5, and more preferably 2 mm or less, which is sufficiently smaller than the pupil diameter. However, if the distance between the horizontal take-out mirrors 2120 is smaller than 0.5 mm, the numerical aperture becomes small and a problem occurs in the resolution. Therefore, the distance P between the horizontal take-out mirrors is preferably in the following range.
0.5mm ≤ P ≤ 2.0mm ... Conditional expression (2)

As shown in FIG. 1, when the observer looks at the displayed image, the light flux responsible for the angle of view on the left side of the image is emitted from the left side of the light guide plate 2, and the light flux responsible for the angle of view on the right side of the image is emitted from the light guide plate. It is emitted from the right side of 2 and is incident on the observer's eye.

If the horizontal mirror group 212 is arranged between the horizontal propagation section 211 and the vertical light guide section 22 as in the present embodiment, a place where the luminous flux having a large propagation angle is close to the entrance surface (left side of the light guide plate in FIG. 2). A luminous flux with a small propagation angle is required at a location far from the incident surface (on the right side of the light guide plate in FIG. 2).

In the propagation in the horizontal propagation section 211, the front surface 2111, the back surface 2112, and the upper surface 2113 are totally reflected, but the lower surface 2114 has a reflectance lower than 100% due to the reflection by the transmission reflective film, and the propagating light is reflected depending on the number of reflections. The amount of light decreases.

When the horizontal mirror group 212 is arranged between the horizontal propagation section 211 and the vertical light guide section 22 as in this embodiment, the number of reflections at each angle is equalized and the number of reflections on the lower surface 2114 of the horizontal propagation section is reduced. The light utilization efficiency can be improved. In this way, there is an advantage that the propagation angle and the required location can be set in a suitable relationship. Further, unlike the lower surface 2114 of the horizontal propagation portion, the lower surface 2124 of the horizontal mirror group does not need to reflect. Therefore, the region where the light flux emitted from the lower surface 2124 of the horizontal mirror group is emitted and the region where the light flux of the vertical propagation portion 221 is incident can be joined, and the horizontal light guide unit 21 and the vertical light guide unit 22 can be easily integrated. can do. As a result, the positional relationship between the horizontal light guide unit 21 and the vertical light guide unit 22 can be maintained with high accuracy, and a good image can always be displayed.

As described above, the configuration of this embodiment is based on the reduction of the number of reflections by the reflective transmission film as compared with the case where the horizontal mirror group 212 is arranged on the upper surface 2113 side of the horizontal propagation portion 211 as in Patent Document 2 and Patent Document 3. There are merits of improving light utilization efficiency and integrating the light guide plate. Further, the configuration of this embodiment is such that the horizontal mirror group 212 is arranged in the horizontal propagation portion 211 and the light flux finally reflected on the lower surface of the horizontal propagation portion 211 is reflected by the mirror group as in Patent Document 1. There is a similar merit compared to the case of.

In the horizontal mirror group 212 of this embodiment, the distance between the adjacent horizontal take-out mirrors 2120 is always set to be equal to 1 mm, and the height (Y direction) is changed according to the position of the horizontal take-out mirror 2120. The horizontal extraction mirror near the incident surface 2115 of the horizontal propagation portion is high, and the height is set lower as the distance from the incident surface 2115 increases (depending on the distance in the Z direction). Since the propagating luminous flux totally reflected by the upper surface 2113 of the horizontal propagation portion is incident on the horizontal extraction mirror 2120, it is preferable to increase the distance from the upper surface 2113 of the horizontal propagation portion as the distance from the incident surface 2115 of the horizontal propagation portion increases. This is because, as described above, the absolute value of the propagation angle of the propagating luminous flux that becomes the effective luminous flux becomes smaller according to the distance from the incident surface 2115 of the horizontal propagating portion, so that the height of the horizontal extraction mirror 2120 is set to the propagation angle. It is lowered according to the absolute value. The incident surface 2115 side of the horizontal propagating portion is a region where a propagating luminous flux having a large propagating angle of ± 45 ° becomes an effective luminous flux, and is horizontal so that the gap between the luminous fluxes is reduced when this propagating light flux is deflected by the horizontal extraction mirror 2120. The take-out mirror 2120 is set as high as 3.0 mm. The vicinity of the center of the horizontal mirror group 212 is a region where the propagating luminous flux having a median propagation angle of ± 32 ° becomes an effective luminous flux, and the horizontal extraction mirror 2120 is set to a medium height of 1.8 mm. The side opposite to the incident surface of the horizontal mirror group 212 is a region where a small propagation light flux with a propagation angle of ± 19 ° becomes an effective light flux, and the horizontal extraction mirror 2120 is set low to 1.2 mm. In this way, the height of the horizontal extraction mirror 2120 is changed according to the propagation angle of the propagating luminous flux that becomes the effective luminous flux.

In addition, in FIGS. 4A and 4B, the heights of the plurality of horizontal take-out mirrors 2120 are all different to reduce the heights linearly. However, the height may be reduced stepwise by reducing the height every few sheets, or the height may be reduced non-linearly (for example, along a sine curve). Moreover, you may combine them.

4 (C) and 4 (D) are explanatory views of a method of determining the height of the horizontal take-out mirror.

FIG. 4C will explain the upper limit of the height of the horizontal take-out mirror 2120.

In the horizontal extraction mirror 2120 of this embodiment, the first region 2121 is a half mirror, the second region is a high reflection mirror, and the light ray 54 toward the boundary between the first region 2121 and the second region 2122 is a horizontal propagation portion. It is incident on the horizontal mirror group 212 from 211.

In order to limit the number of half mirrors through which the light beam 54 is transmitted to N or less, the height of the horizontal take-out mirror 2120 N before the light beam 54 is specified so as to grab the upper end of the horizontal take-out mirror 2120 on the front side (incident surface side). Then, based on this, the upper limit of the height of the target horizontal extraction mirror 2120 was set. The number of half mirrors parallel to the light beam 54 and transmitted by the light beam reflected in the second region 2122 is preferably 3 or less. Let Lu be the distance in the Z-axis direction from the boundary between the first region 2121 and the second region 2122 of the target horizontal extraction mirror 2120 to the upper end of the horizontal extraction mirror 2120 N before. This distance Lu is half the width of the distance PN between the target horizontal take-out mirror 2120 and the horizontal take-out mirror 2120 N pieces before and the width of the horizontal take-out mirror 2120 N pieces before when the horizontal take-out mirror 2120 is arranged at an angle of θ °. Is required from. It is assumed that the ray 54 having a propagation angle ω is incident on the boundary between the first region 2121 and the second region 2122 of the target horizontal extraction mirror 2120. At that time, at the position of the upper end of the horizontal extraction mirror 2120 N pieces before, the ray 54 sets the height of Lu × tanω from the height of the boundary between the first region 2121 and the second region 2122 of the target horizontal extraction mirror 2120. pass. Here, if the horizontal take-out mirror 2120 N before is set to a height that does not block the light beam 54, the number of transmitted light beams parallel to the light beam 54 and reflected in the second region 2122 can be set to N or less. That is, the height of the horizontal take-out mirror 2120 N pieces before may be set to H / 2 <Lu × tanω. The same applies to the target horizontal take-out mirror 2120.

The lower limit of the height of the horizontal take-out mirror 2120 will be described with reference to FIG. 4 (D).

A ray 55 is incident on the upper end of the horizontal extraction mirror 2120, is reflected by the first region 2121 of the horizontal extraction mirror, and passes between the target horizontal extraction mirror 2120 and the previous horizontal extraction mirror 2120. .. At this time, if the height H of the horizontal extraction mirror 2120 is lower than the pitch P1 of the horizontal extraction mirror 2120, the distance Ll between the previous horizontal extraction mirror 2120 and the reflected light 55 becomes large, and the deflection light flux group becomes There will be a gap. The lower limit of the height of the horizontal extraction mirror 2120 is such that a gap of a predetermined width B or more is not formed in the deflection light flux group of the horizontal extraction mirror 2120. Preferably, the gap of the deflected luminous flux group has a predetermined width B ≦ 0.5 mm. In the figure, Ll1 is the distance in the Z direction of the horizontal extraction mirror 2120, and Ll1 = H / tan θ. Further, Ll2 is the distance that the reflected light of the luminous flux 55 travels in the Z direction from the reflected position to the lower surface 2124 of the horizontal mirror group, and Ll2 = H × tanα. Under such conditions, the height H of the horizontal take-out mirror 2120 should satisfy the relationship of the conditional expression (3).

In the conditional expression (3), N should be 3 or less. In this example, N was set to 2. If the upper limit of the conditional expression is exceeded, the number of transmissions of the half mirror increases, which causes a problem of light loss.

In this embodiment, the height of the horizontal extraction mirror is determined by the conditional expression (3), but the height is not limited to this, and the height of the vertical extraction mirror in the vertical mirror group is determined by the conditional expression (3). May be good.

FIG. 5A shows an XY cross-sectional view of the vertical light guide portion in the display device of this embodiment.

As shown in FIG. 5A, the vertical light guide unit 22 is composed of a vertical propagation unit 221 and a vertical mirror group 222. The vertical propagation portion 221 is a flat plate, and the front surface 2211, the back surface 2212, and the upper surface 2213 are polished surfaces, and the other three surfaces are provided with a light-shielding film (light-shielding portion) that shields unnecessary light. The upper surface 2213 of the vertical propagation portion is an incident surface, and the light flux from the horizontal light guide portion is incident from the incident surface. Further, the region of the front surface 2211 (second ejection surface) of the vertical propagation portion that is joined to the vertical mirror group 222 is defined as an emission region, and light that has passed through at least a part of the vertical propagation portion is emitted from the emission region. .. The propagating luminous flux incident on the vertical propagating portion 221 is propagated in the vertical direction while repeating internal reflection on two or less of the four planes parallel to the vertical direction of the vertical propagating portion 221 (front surface 2211 and back surface 2212). The vertical mirror group 222 is arranged so as to face the back surface 2212 (second reflecting surface) of the vertical propagation portion. The vertical mirror group 222 includes a plurality of vertical take-out mirrors 2220 having a transmission-reflecting surface that transmits a part of the incident light beam and reflects a part of the incident light beam, and tilts the vertical take-out mirrors 2220 in the XY cross section and makes them parallel to each other. They are arranged side by side in the Y-axis direction. The outer shape of the vertical mirror group 222 is a flat plate shape, and the front surface 2221 and the back surface 2222 are polished surfaces. The vertical propagation section 221 and the vertical mirror group 222 are the widest in the horizontal direction (Z-axis direction), then the widest in the vertical direction (Y-axis direction), and the narrowest in the depth direction (X-axis direction). .. The vertical mirror group 222 is arranged on the observer's eye 5 side of the vertical propagation section 221, and the front surface 2211 of the vertical propagation section 221 and the back surface 2222 of the vertical mirror group are joined to form the vertical propagation section 221 and the vertical mirror group 222. It is integrated. A transmissive reflective film is applied to the joint surface between the front surface 2211 of the vertical propagation portion 221 and the back surface 2222 of the vertical mirror group 222, so that a part of the incident light beam is transmitted and a part of the incident light beam is reflected.

The lower surface 2124 of the horizontal mirror group 212 of the horizontal light guide unit 21 shown in FIG. 3 (B) and the upper surface 2213 of the vertical propagation unit 221 of the vertical light guide unit 22 shown in FIG. 5 are joined to join the horizontal light guide unit. 21 and the vertical light guide unit 22 are integrated.

The propagating luminous flux reflected by the horizontal extraction mirror of the horizontal light guide section 21 enters the upper surface 2213 of the vertical propagating section 221 and enters the inside of the vertical propagating section 221 between the front surface 2211 and the back surface 2212 of the vertical propagating section 221. It propagates in the vertical propagation section 221 while repeating the inner surface reflection. The portion of the front surface 2211 of the vertical propagation portion 221 that is joined to the back surface 2222 of the vertical mirror group is incident on the vertical mirror group 222 through a part of the propagating light flux by the transmission reflection film provided on the joint surface. , A part of it is reflected and propagates in the vertical propagation section 221 again.

The vertical mirror group 222 is provided with 28 vertical take-out mirrors 2220 tilted 58 ° in the XY direction with respect to the back surface 2212 and arranged in parallel with each other. Each vertical extraction mirror 2220 reflects a part of the propagating light flux incident on the vertical mirror group 222 and deflects it toward the front surface 2221 of the vertical mirror group, and at the same time, transmits a part of the propagating light beam. The propagating light flux transmitted through the first vertical extraction mirror 2220 is reflected by the next vertical extraction mirror 2220 and deflected toward the front 2221 of the vertical mirror group 222.

The front surface 2221 of the vertical mirror group 222 is parallel to the back surface 2212 of the vertical propagation portion 221. So it is totally reflected. On the other hand, in the propagating light flux deflected by the vertical extraction mirror 2220, the angle of incidence on the front surface 2221 of the vertical mirror group 222 is smaller than the critical angle, and the propagating light flux is from the front surface 2221 of the vertical mirror group 222 to the observer's eye 5. Is ejected in the direction of (third direction side). As a result, the image can be displayed by injecting a light flux into the observer's eye 5. The incident angle is an angle formed by the incident direction of the luminous flux and the normal line of the incident surface.

Similarly to the horizontal light guide unit 21, the vertical light guide unit 22 is configured so that the propagating light flux at one angle is deflected by a plurality of vertical extraction mirrors 2220, so that the luminous flux width of the deflected light beam group is propagated. It is wider than the luminous flux width of.

FIG. 6 is a schematic view of the vertical take-out mirror of this embodiment.

The vertical take-out mirror of this embodiment will be described with reference to FIG.

As the vertical mirror group 222 of this embodiment, 28 vertical take-out mirrors 2220 are used. In this embodiment, the number of horizontal take-out mirrors is larger than the number of vertical take-out mirrors. This sets the horizontal angle of view to be larger than the vertical angle of view among the angles of view for the observer's eyes, and further, the distance between the observer's eyes and the horizontal mirror group is the distance between the observer's eyes and the vertical mirror group. This is because it is larger than the distance. This configuration makes it possible to always provide a good image to the observer.

FIG. 6 shows 6 vertical take-out mirrors 2220 out of 28 vertical take-out mirrors 2220. The vertical extraction mirror 2220 of this embodiment is a rectangular mirror having a long axis in the Z direction. As the vertical extraction mirror 2220 of this embodiment, a polarization beam splitter (PBS), which is a polarization splitting mirror, is used. More specifically, a wire grid polarizing plate which is a kind of structure birefringent type PBS using a sub-wavelength structure (Sub-Wavelength Structure: SWS) is used. The wire grid polarizing plate is formed by arranging a large number of dielectric wires 2226 (metal wires, for example aluminum) on an optical substrate 2225 (for example, a glass substrate) at a pitch of wavelength or less (about 100 nm) in a grid shape. The wire grid polarizing plate has the property of transmitting light (P-polarized light) that vibrates in the electric field in the direction 2227 parallel to the wire grid (metal wire) and reflecting light (S-polarized light) that vibrates the electric field in the direction perpendicular to the wire grid. be. That is, it is a polarization beam splitter that can select the reflection / transmission polarization direction depending on the direction of the wire grid.

In this embodiment, the directions of the wire grids of the vertical extraction mirrors 2220 are alternately rotated by 90 ° and arranged so that the directions of the wire grids of the adjacent vertical extraction mirrors 2220 are orthogonal to each other. Specifically, the first polarization beam splitter, which is one of the vertical extraction mirrors 2220, has the wire grid oriented at 90 ° with respect to the long axis of the vertical extraction mirror, and the second vertical extraction mirror 2220 next to the vertical extraction mirror 2220. The polarization beam splitter set the direction of the wire grid to 0 °. The first incident vertical extraction mirror 2220 splits the propagating light into a reflected light and a transmitted light, deflects the reflected light to the front 2221 of the vertical mirror group, and reflects the transmitted light to the adjacent vertical extraction mirror 2220 to make a vertical mirror. It was configured to deflect to the front 2221 of the group. Since the orientation of the wire grid of the first vertical extraction mirror 2220 and the orientation of the wire grid of the adjacent vertical extraction mirror 2220 are orthogonal to each other, the transmitted light beam of the first vertical extraction mirror 2220 is completely reflected by the adjacent vertical extraction mirror 2220. Orthogonal. The light transmitted through the first polarization beam splitter is reflected by the second polarization beam splitter and emitted from the light guide plate 2, and the light reflected by the first polarization beam splitter is emitted from the light guide plate 2 without passing through the second polarization beam splitter. I'm letting you. Therefore, the reflected light beam and the transmitted light beam are branched 1: 1 by the vertical extraction mirror 2220 in which the propagating light flux is first incident, and the transmitted light beam is reflected by the vertical extraction mirror 2220 incident next, so that one light beam is two. It is ejected from the vertical extraction mirror 2220 toward the observer's eyes. As a result, a polarized luminous flux group is formed, and the luminous flux width of the polarized luminous flux group is expanded beyond the luminous flux width of the propagating luminous flux. When a dielectric multilayer film type PBS is used as the vertical extraction mirror 2220 instead of the structural birefringence type PBS, the P polarization transmitted by the first incident vertical extraction mirror 2220 is transferred to the next incident vertical extraction mirror. Even 2220 can only be configured to be transparent. However, in the structural birefringence type PBS, the polarization direction of the transmitted polarized light and the reflected polarized light can be changed by changing the direction of the wire grid. Therefore, if the structural birefringence type PBS is used as the vertical extraction mirror 2220 as in this embodiment, the P polarization transmitted by the vertically incident vertical extraction mirror 2220 can be reflected by the adjacent vertical extraction mirror 2220. become. In this embodiment, an organic electroluminescence (OLED) panel that emits light having a low degree of polarization is used as the display element 4. However, when a liquid crystal panel or the like that emits light having a high degree of polarization is used as the display element 4, a depolarization plate may be provided in the optical path between the display element 4 and the vertical mirror group 222. Specifically, a depolarization plate may be arranged between the display element 4 and the incident optical system 3, or between the incident optical system 3 and the light guide plate 2.

FIG. 7 shows an explanatory diagram of the vertical take-out mirror of this embodiment.

FIG. 7 shows five vertical take-out mirrors 2220.

A propagating luminous flux having a small propagating angle ω guides the inside of the vertical light guide unit 22, and half of the light amount is reflected by the vertical extraction mirror 2220 that arrives first, and half is transmitted. The reflected propagating light flux is deflected toward the front 2221 of the vertical mirror group and is emitted toward the observer's eye. The transmitted luminous flux is reflected by the next vertical extraction mirror 2220, deflected in the direction of the front 2221 of the vertical mirror group, and is emitted toward the observer's eye.

At this time, the light beam transmitted through the first vertical extraction mirror 2220 and reflected by the next second vertical extraction mirror 2220 and first incident on the second vertical extraction mirror 2220 and reflected by the second vertical extraction mirror 2220. The light beam is arranged side by side. This reduces the gap between the luminous fluxes in the polarized luminous flux group emitted toward the observer's eyes, and realizes a configuration in which the observer can observe each angle of view with a uniform light amount distribution.

At this time, by arranging the height H and the interval P of the vertical extraction mirror 2220 so as to satisfy the conditional equation (4), it is possible to realize an appropriate configuration in which the gap between the luminous fluxes in the polarized luminous flux group is reduced.

If the upper limit is exceeded, the structure passes through three or more polarizing plates, and a gap is generated in the propagating light flux reaching the extraction mirror, and as a result, the gap in the deflection light flux width becomes large, which becomes a problem. If it is less than the lower limit, the distance between the deflected luminous flux and the extraction mirror becomes large, and as a result, the gap of the deflected luminous flux width becomes large, which becomes a problem.

It becomes larger than the average diameter (about 4 mm) of the pupil (pupil) of the observer's eye, and the light amount distribution due to the gap of the reflected light flux becomes conspicuous, which is a problem. If it is less than the lower limit, the width of the reflected light flux becomes too narrow and the resolving power is lowered, which causes a problem.

In addition, the structural birefringence type polarizing plate is characterized in that it can maintain high performance (reflectance, transmittance) in a wide range of incident angle characteristics and wavelength characteristics as compared with the dielectric film multilayer film type polarizing beam splitter. be. The vertical extraction mirror 2220 has a wide incident angle range of 45 ° or more and 70 ° or less, and is used in a wide band with visible light of 400 nm or more and 700 nm or less. You will need it.

In this way, the width of the luminous flux emitted from the light guide plate is expanded, and the light amount distribution in the expanded luminous flux is made uniform. As a result, an EMB (Eye Motion Box) of 15 mm is secured at the position of the observer's eye, and even if the pupil position is moved when observing the peripheral portion of the wide angle of view display image, the observer's eye The luminous flux from the displayed image can always be incident on the pupil, and a high-quality image can be provided.

In FIG. 5B, in addition to the propagating light flux in the vertical light guide unit 22 and the vertical light guide unit 22 shown in FIG. 5A, the light flux incident on the vertical light guide unit 22 from the outside world is shown by a chain line. Indicated.

The luminous flux from the outside world passes through the back surface 2212 of the vertical propagation portion, the front surface 2211, and the back surface 2222 of the vertical mirror group in this order, and further passes through the vertical extraction mirror 2220 and the front surface of the vertical mirror group to reach the observer's eye 5. do. Since the wire grid polarizing plate is used for the vertical extraction mirror 2220 of this embodiment, the polarized light flux in the direction perpendicular to the arrangement direction of the wire grid can pass through the wire grid polarizing plate. As a result, the observer can observe the outside world through the vertical light guide unit 22, and the optical see-through function is exhibited.

Further, since the optical path of the propagating light beam from the display element 4 and the optical path of the light beam from the outside world can be overlapped on the same optical path from the vertical extraction mirror 2220 to the observer's eye 5, the light path from the display element 4 can be overlapped with the outside world. Images can be overlaid and displayed.

As described above, the display device of the present embodiment enables the observer to observe a high-quality display image with a wide angle of view in both the horizontal and vertical directions, and also enables the outside world to be observed by optical see-through, and both are superimposed. Can be observable.

Then, the incident optical system 3 in the display device of the present embodiment XY cross sections of the light from the display element 4 so that the propagating light flux is reflected by the upper surface 2113 of the horizontal propagating portion 211 and the back surface 2212 of the vertical propagating portion 221. It is obliquely incident in two directions, the inside and the YZ cross section. As a result, the width of the luminous flux irradiating the observer's eyes can be expanded in the two-dimensional directions of the horizontal direction and the vertical direction, and the angle of view is widened in the two-dimensional direction.

In the display device of this embodiment, a combination of a half mirror and a mirror is used for the horizontal extraction mirror 2120 of the horizontal light guide unit 21, but the present invention is not limited to this. For the horizontal extraction mirror 2120, only a half mirror or a combination of a plurality of polarizing plates having intersecting wire grid orientations may be used. As the configuration of the horizontal mirror group 212, the configuration of the vertical mirror group described above (a configuration in which the wire grid polarizing plates are alternately rotated and arranged) may be applied.

Further, although a wire grid polarizing plate is used for the vertical extraction mirror 2220 of the vertical light guide unit 22, the present invention is not limited to this, and a half mirror or a combination of a half mirror and a mirror may be used.

Further, in the display device of this embodiment, a configuration is used in which the wire grid polarizing plates are alternately rotated by 90 ° and arranged on the vertical extraction mirror 2220 of the vertical light guide unit 22. However, the adjacent wire grids are not limited to 90 ° rotation, but may be 30 °, 45 °, 60 °, 120 °, 135 °, and 150 ° rotation. In short, it is preferably 30 ° or more and 150 ° or less, but it is sufficient that the adjacent wire grids face different directions.

Further, in the light guide plate of the present embodiment, the light beam is guided in the horizontal direction (Z direction) in the horizontal light guide section, and the light beam is guided in the vertical direction (Y direction) in the vertical light guide section. rice field. However, as described in Patent Document 3, the light beam is guided vertically (Y direction) in the horizontal light guide section and the light flux is guided vertically (Z direction) in the vertical light guide section. May be. It is more preferable to configure the light guide plate as in this embodiment because the long axis direction of the vertical mirror group coincides with the horizontal direction and the visibility of the vertical mirror group of the observer can be reduced. In the display device of this embodiment, the propagation direction (first direction) of the light beam of the horizontal propagation portion and the propagation direction (second direction) of the light beam of the vertical propagation portion are orthogonal to each other, and the direction and the light beam from the light guide plate are orthogonal to each other. Was configured to be orthogonal to the ejection direction (third direction). However, they do not necessarily have to be orthogonal, and may be configured to intersect.

Further, in the light guide plate of this embodiment, the horizontal mirror group 212 is arranged between the horizontal propagation unit 211 and the vertical propagation unit 221. However, the horizontal mirror group 212 may be arranged between the upper surface 2113 of the horizontal propagation portion 211 and the vertical propagation portion 221, and the mirror group may be arranged in the horizontal propagation portion 211 as in Patent Document 1. .. However, in that case, it is not preferable to have a configuration in which the luminous flux last reflected on the lower surface of the horizontal gene transfer portion 211 is reflected by the mirror group as in Patent Document 1. As in this embodiment, it is preferable that the light flux finally reflected by the upper surface 2113 of the horizontal gene transfer portion 211 is reflected by the mirror group. In other words, it is preferable that the luminous flux having a central angle of view (the luminous flux emitted from the mirror group in parallel with the Y direction) is incident on the mirror of the mirror group at an incident angle larger than 45 °. With this configuration, the light beam having a larger absolute value of the propagation angle can be emitted as an effective light flux from the side closer to the incident surface of the horizontal light guide portion, and the same effect as that of the present embodiment can be obtained.

Further, in the light guide plate of this embodiment, the vertical mirror group 222 is arranged between the vertical propagation portion 221 and the observer's eye 5. However, the vertical mirror group 222 is located between the back surface 2212 of the vertical propagation portion 221 and the observer's eye 5 (that is, the side in the direction in which the light flux from the light guide plate is emitted from the back surface 2212 of the vertical propagation portion 221). It may be arranged, and the mirror group may be arranged in the vertical propagation section 221. However, even in that case, it is preferable that the light flux finally reflected by the back surface 2212 of the vertical propagation portion 221 is reflected by the mirror group. In other words, it is preferable that the luminous flux having a central angle of view (the luminous flux emitted from the mirror group in parallel with the X direction) is incident on the mirror of the mirror group at an incident angle larger than 45 °.

FIG. 8 shows a display device of Example 2 to which the present invention can be applied.

The difference between the present embodiment and the first embodiment is that the configurations of the horizontal light guide unit 21 and the vertical light guide unit 22 are changed. Specifically, in the horizontal light guide unit 21, the height of the horizontal propagation unit 211 is made higher than the aperture stop of the incident optical system of the horizontal light guide unit 21, and the horizontal propagation unit 21 and the horizontal mirror group 22. This is the point where the transmissive reflective film placed on the joint surface of the above is eliminated. In the vertical light guide section 22, the width of the vertical propagation section 221 in the X-axis direction is made larger than the width of the horizontal propagation section 211 in the X-axis direction, and the junction surface between the vertical propagation section 221 and the vertical mirror group 222. This is the point where the placed transmission / reflection film is eliminated.

9 (A) and 9 (B) show the horizontal light guide section of the comparative example, and FIG. 9 (C) shows the horizontal light guide section of the present embodiment.

The configuration of the horizontal light guide unit in this embodiment will be described with reference to FIGS. 9 (A), 9 (B), and 9 (C).

In FIGS. 9 (A), 9 (B), and 9 (C), the horizontal light guide unit 21 including the horizontal propagation unit 211 and the horizontal mirror group 212, and the incident optics including the projection lens 31 and the connection unit 32. The system 3 and the display element 4 are schematically displayed.

The luminous flux emitted from each pixel of the display element 4 is converted into a parallel luminous flux by the projection lens 31, and the luminous flux has an angle of view corresponding to the pixel position of the display element 4. The angle of view light flux from the projection lens 31 is incident on the connection portion 32, and a part of the angle of view light flux is internally reflected by the connection portion 32 to reach the junction region 33 with the incident surface 2115 of the horizontal propagation portion, and the other one. The portion reaches the joint region 33 without internal reflection at the connecting portion 32. As a result, two incident light fluxes in the plus direction and the minus direction are generated with respect to the major axis Ax of the horizontal gene transfer portion 211. Then, each angle of view light flux is limited in the light beam width at the junction region 33 and is incident on the horizontal propagation portion 211 to become a propagation light beam. That is, the junction region 33 between the connection portion 32 of the incident optical system and the incident surface 2115 of the horizontal propagation portion has the function of the aperture stop 33 of the incident optical system 3. That is, a light beam limited by the aperture stop 33 of the incident optical system is incident on the horizontal light guide unit 21.

As shown in FIG. 9A, in the comparative example, the entire left surface 2115 of the horizontal propagation portion is joined to the connection portion 32 of the incident optical system, and the left surface 2115 of the horizontal propagation portion is an opening of the incident optical system. It is the same size as the aperture 33. The propagating luminous flux incident from the incident surface 2115 of the horizontal propagation portion is internally reflected by the upper surface 2113 and the lower surface 2114 of the horizontal propagation portion and propagates inside the horizontal propagation portion 211. On the incident surface 2115 of the horizontal propagation section, the incident surface is incident in the YZ direction in two directions, a plus direction and a minus direction, with respect to the long axis Ax of the horizontal propagation section 211, and the inside of the horizontal propagation section 211 can be filled with the propagating luminous flux. can. As a result, the propagating luminous flux can be evenly distributed on the lower surface 2124 of the horizontal mirror group 212 on the side of the horizontal propagating portion close to the incident surface 2115.

In the horizontal light guide section 21 of the comparative example of FIG. 9A, the transmission reflection film is not installed on the joint surface between the lower surface 2114 of the horizontal propagation section and the upper surface 2123 of the horizontal mirror group, and the transmission reflection film is not installed in the horizontal propagation section 211. The propagating luminous flux passes through the joint surface and is incident on the horizontal mirror group 212. At this time, the propagating luminous flux in the horizontal propagating portion 211 propagates a distance Lp from the start position of the joint surface between the lower surface 2114 of the horizontal propagating portion and the upper surface 2123 of the horizontal mirror group, and the propagating luminous flux is gapped in the horizontal mirror group 212. Has arrived without.

Further, We in FIG. 9A is a required luminous flux region required for the central angle of view, and is required to have a width equivalent to the pupil diameter of a display device called EMB, and usually secures 6 mm to 15 mm.

However, in the comparative example of FIG. 9A, the propagating light flux reaches only a part of the required light flux region We at the position of the lower surface 2124 of the horizontal mirror group 212. In this case, the luminous flux having a sufficient width does not reach the observer's eyes, which causes a problem that the image is chipped.

In FIG. 9B, a transmission reflection film is arranged on the joint surface between the lower surface 2114 of the horizontal propagation portion and the upper surface 2123 of the horizontal mirror group with respect to the horizontal light guide portion 21 of the comparative example of FIG. 9A. This is a comparative example. Example 1 is also in this embodiment. In this case, a part of the propagating luminous flux in the horizontal propagating portion 211 is transmitted to the horizontal mirror group 212 at the junction surface between the lower surface 2114 of the horizontal propagating portion and the upper surface 2123 of the horizontal mirror group, and the other part is reflected. Then, it propagates in the horizontal propagation section 211 again. By repeating this, the propagating luminous flux reaches the end 2116 of the horizontal propagating portion, and the propagating luminous flux is spread over the entire area of the horizontal mirror group 212. Therefore, the polarized luminous flux group deflected by the horizontal extraction mirror 2120 exists in the entire region of the required luminous flux region We of the central angle of view, and the luminous flux having a sufficient width can reach the observer's eyes. However, a transmissive reflective film is arranged on the joint surface between the lower surface 2114 of the horizontal propagating portion and the upper surface 2123 of the horizontal mirror group, and only a part of the propagating light flux incident on the transmissive reflecting film is reflected. For example, if the transmittance of the transmissive reflective film is 25% and the reflectance is 65%, the amount of light of the propagating luminous flux decreases by 35% for each reflection. As the propagation distance becomes longer, the number of reflections by the transmitted reflection film increases, so that the polarized light flux group emitted from the horizontal light guide unit 21 has a light amount distribution according to the propagation distance, and the light amount in a place with a high light amount is reduced. The light amount distribution is corrected according to the place where the light amount is low. Therefore, a light amount loss occurs, which causes a problem.

FIG. 9C shows the horizontal light guide portion of this embodiment.

In the horizontal propagation section 21 of this embodiment, the height H (width in the Y-axis direction) of the horizontal propagation section 211 is set higher by Hc than the height Ha of the aperture stop 33 with the incident optical system. The length in the Y-axis direction perpendicular to the lower surface 2114 (the overhanging surface described later) of the horizontal propagation portion 21 is longer than 1 times and shorter than 2 times the width of the aperture of the aperture diaphragm 33 of the incident optical system in the Y-axis direction. .. That is, 0 <Hc <Ha. The length of the horizontal propagation portion 21 in the Y-axis direction here corresponds to the distance between the two total reflection surfaces (upper surface 2113 and lower surface 2114) of the horizontal propagation portion 21.

In the comparative examples of FIGS. 9 (A) and 9 (B), the height H = Ha of the horizontal propagation portion 211.

Similar to the comparative example of FIG. 9A, the horizontal light guide portion 21 of this embodiment also has a connection region 33 with the connection portion 32 on the incident surface 2115 of the horizontal propagation portion in two directions of plus and minus in the YZ cross section. A luminous flux is incident at an angle (± ω) to form a propagating luminous flux. The propagating luminous flux propagates in the horizontal propagating portion 211 while being totally reflected by the lower surface 2114 and the upper surface 2113 of the horizontal propagating portion. Further, also in the horizontal light guide portion of this embodiment, the transmission reflection film is not installed on the joint surface between the lower surface 2114 of the horizontal propagation portion and the upper surface 2123 of the horizontal mirror group. Therefore, 90% or more (more preferably 95% or more) of the propagating luminous flux incident on the injection region of the lower surface 2114 of the horizontal propagating portion 211 passes through the junction surface and is incident on the horizontal mirror group 212. Therefore, after the horizontal propagation portion 211 enters the region where the horizontal propagation portion 211 joins with the horizontal mirror group 212, the number of reflections is only once on the upper surface 2113 of the horizontal propagation portion. It is necessary to deliver each angle of view luminous flux to the required region by the number of reflections at one time.

Here, assuming that one propagation cycle starts from the lower surface 2114 of the horizontal propagation section, is reflected by the upper surface 2113 of the horizontal propagation section, and reaches the lower surface 2114 of the horizontal propagation section again, the propagation distance La per propagation cycle. Is given by the conditional expression (5).
La = H / tanω × 2 ... Conditional expression (5)

As shown in the conditional equation (5), the propagation distance La per propagation cycle becomes longer in proportion to the height H of the horizontal light guide portion.

The horizontal light guide unit 21 of this embodiment has a propagation distance by setting the height H (width in the Y-axis direction) of the horizontal propagation unit 211 to be higher than the height Ha of the aperture stop 33 of the incident optical system by Hc. Can be extended by 2 × Hc / tanω. As a result, the propagating luminous flux can reach the far end of the required luminous flux region We at each angle of view (the position farthest from the incident surface 2115 of the required luminous flux region We). In FIG. 9C, the angle of view luminous flux having a central angle of view is shown as an example, but according to the configuration of this embodiment, the propagating luminous flux is transmitted to a position beyond the far end of the required luminous flux region We in the central angle of view luminous flux. I have delivered it.

In order to reach the far end of the required luminous flux region We at each angle of view, the height H of the horizontal gene transfer portion is set to the height of the aperture diaphragm 33 of the incident optical system so as to satisfy the conditional equation (6). It is better to set it higher by Hc than Ha.

ただし、
Ｈは水平伝搬部２１１の高さ（Ｙ軸方向の幅）
Ｈａは入射光学系の開口絞り３３の高さ
Ｈｃは水平伝搬部２１１の高さを入射光学系の開口絞り３３の高さよりも高くする量
Ｈｍは水平ミラー群２１２の高さ
Ｌｏは水平伝搬部２１１と水平ミラー群２１２の接合面の最も入射面２１１５側の位置から必要光束領域Ｗｅの最も入射面２１１５側の位置までの距離
Ｗｅは必要光束領域の幅
ωは伝搬角
… 条件式（６）

however,
H is the height of the horizontal gene transfer portion 211 (width in the Y-axis direction)
Ha is the height of the aperture stop 33 of the incident optical system Hc is the amount that makes the height of the horizontal propagation section 211 higher than the height of the aperture stop 33 of the incident optical system Hm is the height of the horizontal mirror group 212 Lo is the horizontal propagation section The distance We from the position on the most incident surface 2115 side of the junction surface between 211 and the horizontal mirror group 212 to the position on the most incident surface 2115 side of the required light beam region We is the width of the required light beam region ω is the propagation angle ... Conditional expression (6)

On the other hand, if the height of the horizontal gene transfer portion 211 is set higher than the aperture stop 33 of the incident optical system, the inside of the horizontal gene transfer unit 211 cannot be filled with the propagating luminous flux. A gap of the propagating light flux that does not exist in the horizontal propagating portion 211 is generated, but if the gap of the propagating light flux is configured so as not to be applied to the required light flux region Wp at each angle of view, only the above-mentioned advantages can be obtained. Be done. Even in the example of the angle of view light flux having the central angle of view shown in FIG. 9C, the gap of the propagating light beam is configured so as not to cover the required region We.

For that purpose, a region where the height H of the horizontal propagation portion 211 is higher by Hc than the height Ha of the aperture stop 33 of the incident optical system is connected to the connection portion 32 from the end of the joint surface between the horizontal propagation portion 211 and the horizontal mirror group 212. The configuration that overhangs to the side is important. In FIG. 9C, the overhang amount is Lh, and the light flux reflected on the upper surface of the connection portion 32 of the incident optical system 3 is placed between the overhang surface (in the horizontal direction, the incident surface 2115 of the horizontal propagation portion and the mirror group 212). It is reflected on the surface that is arranged and faces the upper surface 2113). As a result, the position closest to the arrival of the propagating luminous flux (closest to the incident surface side of the horizontal propagating portion) is configured to be in front of the required luminous flux region We.

In order to remove the gap of the propagating luminous flux from the required luminous flux region at each angle of view, the horizontal propagating portion 211 should have a configuration in which the overhang amount Lh of the portion Hc higher than the aperture diaphragm 33 of the incident optical system satisfies the conditional equation (7). Just do it.

ただし、
Ｈａは入射光学系の開口絞り３３の高さ
Ｈｃは水平伝搬部２１１の高さを入射光学系の開口絞り３３の高さよりも高くする量
Ｈｍは水平ミラー群２１２の高さ
Ｌｏは水平伝搬部２１１と水平ミラー群２１２の接合面の最も入射面２１１５側の位置から必要光束領域Ｗｅの最も入射面２１１５側の位置までの距離
ωは伝搬角
… 条件式（７）

however,
Ha is the height of the aperture stop 33 of the incident optical system Hc is the amount that makes the height of the horizontal propagation section 211 higher than the height of the aperture stop 33 of the incident optical system Hm is the height of the horizontal mirror group 212 Lo is the horizontal propagation section The distance ω from the position on the most incident surface 2115 side of the junction surface between 211 and the horizontal mirror group 212 to the position on the most incident surface 2115 side of the required light beam region We is the propagation angle ... Conditional expression (7)

As described above, in this embodiment, the propagating light flux of each angle of view is made to reach the required light flux region Wp at each angle of view, and the gap portion of the propagating light flux is configured so as not to be applied to the required light flux region Wp. There is.

That is, it is preferable that the conditional expression (6) and the conditional expression (7) are satisfied at the same time, and the amount Hc that makes the height of the horizontal gene transfer portion 211 higher than the height of the aperture stop 33 of the incident optical system is the conditional expression (8). ) Satisfying the configuration.

ただし、
Ｈは水平伝搬部２１１の高さ（Ｙ軸方向の幅）
Ｈａは入射光学系の開口絞り３３の高さ
Ｈｍは水平ミラー群２１２の高さ
Ｌｏは水平伝搬部２１１と水平ミラー群２１２の接合面の最も入射面２１１５側の位置から必要光束領域Ｗｅの最も入射面２１１５側の位置までの距離
Ｌｈは水平伝搬部２１１が入射光学系の開口絞り３３よりＨｃ高い部分の張出し量
Ｗｅは必要光束領域の幅
ωは伝搬角
… 条件式（８）

however,
H is the height of the horizontal gene transfer portion 211 (width in the Y-axis direction)
Ha is the height of the aperture stop 33 of the incident optical system Hm is the height of the horizontal mirror group 212 Lo is the most required light beam region We from the position on the most incident surface 2115 side of the junction surface between the horizontal propagation portion 211 and the horizontal mirror group 212. The distance Lh to the position on the incident surface 2115 side is the overhang amount We of the portion where the horizontal propagation portion 211 is Hc higher than the aperture diaphragm 33 of the incident optical system. The width ω of the light beam region is the propagation angle ... Conditional expression (8)

As in this embodiment, by making the height H of the horizontal propagation portion of the horizontal light guide portion higher than that of the aperture diaphragm 33 of the incident optical system 3, the propagating light flux of each angle of view can be obtained in the required luminous flux region with a small number of reflections. Can be reached.

In this embodiment, the height of the horizontal propagation portion of the horizontal light guide portion is set higher by Hc than the aperture stop 33 of the incident optical system 3, and the horizontal propagation portion 211 is Hc higher than the aperture stop 33 of the incident optical system. The overhang amount Lh was set appropriately. As a result, a configuration in which the number of reflections on the transmission and reflection surface is 0 is realized, and a display device with reduced light amount loss is realized. That is, in this embodiment, the propagating light beam incident on the horizontal propagating portion 211 is the inner surface of three or more of the four planes (front surface 2111, back surface 2112, upper surface 2113, lower surface 2114) parallel to the horizontal direction of the horizontal propagating portion 211. It is reflected and propagated horizontally.

In the comparative example of FIG. 9B, the luminous flux at the central angle of view is reflected not only by the mirror arranged in the central portion including the required luminous flux region We but also by the mirrors arranged at both ends. It was configured and there was a lot of light loss. However, in this embodiment of FIG. 9C, the luminous flux at the central angle of view is reflected only by the mirrors arranged in the central portion including the required luminous flux region We, and is not reflected by the mirrors arranged at both ends. The light intensity loss is small.

In this embodiment, one end of the lower side (overhanging surface side) of both ends of the opening of the aperture diaphragm is arranged at the same position as the lower surface (overhanging surface) 2114, and the other end of the upper side (reflection surface side) is the upper surface. (Reflective surface) It was arranged below 2113. However, of both ends of the opening of the aperture diaphragm, one end on the upper side (reflection surface side) is arranged at the same position as the upper surface (reflection surface) 2113, and the other end on the lower side (overhanging surface side) is placed on the lower surface (overhanging surface) 2114. It may be placed above the above. However, in this case, the propagation distance can be extended only by Hc / tanω.

FIG. 10 shows the vertical light guide unit 22 of this embodiment.

Also in this embodiment, the vertical light guide unit 22 is composed of a vertical propagation unit 221 and a vertical mirror group 222. The vertical mirror group 222 includes a plurality of vertical extraction mirrors 2220, a wire grid is used for each vertical extraction mirror 2220, and adjacent vertical extraction mirrors 2220 are arranged by rotating the direction of the wire grid by 90 °. In this embodiment, as shown in FIG. 10, a step is provided in the vertical propagation portion 221 and the vertical mirror group 222 is arranged at the step.

The thickness T (width in the X direction) of the vertical propagation portion 221 of this embodiment is larger than the thickness of the vertical propagation portion 221 of the first embodiment. The thickness of the vertical propagation portion 221 of the first embodiment is the same as the thickness of the horizontal light guide portion 21, but the thickness T of the vertical propagation portion 221 of the present embodiment is Tc larger than the thickness Ta of the horizontal light guide portion 21. There is. As a result, the propagating light beam in the vertical propagating section 221 is totally reflected by the back surface 2212 of the vertical propagating section, then incident on the vertical mirror group 222, reflected by the vertical extraction mirror 2220, deflected, and ejected from the front surface 2221 of the vertical mirror group. Then, it is incident on the observer's eye 5.

Here, by making the vertical propagating portion 221 thicker, the propagating light flux can reach the place where each angle of view light flux is required only by total internal reflection once on the back surface 2212 of the vertical propagating part. As a result, it is not necessary to reflect at the joint surface between the vertical propagation portion 221 and the vertical mirror group 222, not only the transmission reflection film becomes unnecessary, but also the vertical propagation portion 221 and the vertical mirror group 222 are integrally formed. This can reduce costs.

11 (A) shows a front view of Example 3 to which the present invention can be applied, and FIG. 11 (B) shows a side view.

The difference between the present embodiment and the second embodiment is that the configurations of the horizontal mirror group and the vertical mirror group are changed, and the horizontal light guide unit 21, the vertical light guide unit 22, and the connection portion 32 of the incident optical system are integrated. It is a point that was made into a structure.

As shown in FIG. 11A, in this embodiment, the entire light guide plate 2 is integrated, and the horizontal take-out mirror 2120 and the vertical take-out mirror 2220 are embedded in the resin molded product. Specifically, the horizontal take-out mirror 2120 and the vertical take-out mirror 2220 are manufactured of glass, inserted into a mold, and molded with resin so as to cover the outside. This is so-called glass insert molding. Therefore, as in the second embodiment, there is no clear boundary between the horizontal propagating portion 211 of the horizontal light guide portion 21 and the horizontal mirror group 212, and the taking-out mirror does not hit the propagating light flux that has not reached the predetermined taking-out position. Can be advanced toward the propagation section and placed.

Further, in this embodiment, the height of the take-out mirror is changed for each place, and the distance (pitch) from the adjacent take-out mirror is also changed, so that the arrangement with a higher degree of freedom is possible. The distance between the extraction mirrors becomes longer as the distance from the incident surface 2115 of the horizontal light guide unit 21 increases. As a result, the gap in the polarized light flux group from the extraction mirror can be reduced, and the polarized light flux group having a more uniform light amount distribution can be incident on the observer's eye to display a high-quality image.

The light guide plate 2 of this embodiment also has a horizontal light guide unit 21 that guides the light from the incident optical system in the Z-axis direction and a vertical light guide unit 22 that guides the light in the Y-axis direction. Then, the horizontal light guide unit 21 includes a horizontal mirror group 212, and guides the light beam that guides the inside of the horizontal light guide unit 21 to the vertical light guide unit 22 by being reflected by the horizontal mirror group 212.

Similar to the second embodiment, the incident surface of the horizontal light guide unit 21 serves as the aperture stop 33 of the incident optical system 3. Further, the distance in the Y-axis direction between the two total reflection surfaces of the horizontal light guide unit 21 is set to be longer than 1 times and shorter than 2 times the opening width in the Y-axis direction of the aperture stop 33. ing.

As shown in FIG. 11B, the vertical light guide unit 22 includes a vertical mirror group 222, and the light beam that guides the inside of the vertical light guide unit 22 is reflected by the vertical mirror 2220 to be deflected in the X-axis direction. , A light beam is emitted from the vertical light guide unit 22 toward the observer's eye 5.

In this embodiment, both the height and the spacing of the plurality of extraction mirrors are changed, but the gap of the deflected luminous flux group can be reduced even if only the spacing of the plurality of extraction mirrors is changed.

The human eye rotates the eyeball when observing different angles of view. On the other hand, there is a gap in the deflection luminous flux group emitted from the light guide plate, and the position and size of the gap differ depending on the angle of view.

When there is a large gap in the luminous flux incident on the observer's eye, the amount of light incident on the pupil of the eye changes, so even if an image with uniform brightness is viewed, bright and dark areas are scattered. looks like. For example, it is a display image with a quality that cannot be said to have a good field of view, as if you were looking at the scenery through a screen door.

On the other hand, in the display devices of Examples 1 to 3, since the gap between the light flux incident on the observer's eyes can be set small at all angles of view, the difference between the bright part and the dark part at each angle of view becomes small, and the observation is performed. It is reduced to the extent that people do not care. It is possible to provide a display device capable of always displaying a good image.

The display devices of Examples 1 to 3 can be applied to, for example, a head-mounted display (including smart glasses, AR glasses, scouters, etc.), a head-up display, a mobile phone display, a 3D display, and the like.

In this embodiment, the display device of the present invention is applied to a smart glass which is an example of a head-mounted display.

FIG. 12 is a diagram of a smart glass 600 of Example 4 to which the present invention can be applied.

The smart glasses 600 is a glasses-type wearable terminal, and is a terminal for so-called augmented reality (AR) that displays various information superimposed on the real world that is actually seen.

The smart glass 600 has a frame and two display devices 1a and a display device 1b. The frame has a rim 61 to which the display device 1a and the display device 1b are joined to the lower surface, and temples 62a and 62b joined to both sides of the rim 61. As the display device 1a and the display device 1b, any of the display devices of Examples 1 to 3 can be used.

Light from the display element (not shown) of the display device 1a is guided by the incident optical system 3a and the light guide plate 2a to the right eye of the observer wearing the smart glasses 600, and the image is displayed on the right eye of the observer. .. Similarly, the light from the display element (not shown) of the display device 1b is guided by the incident optical system 3b and the light guide plate 2b to the left eye of the observer wearing the smart glasses 600, and the image is displayed on the left eye of the observer. Is displayed.

In the smart glass 600 of the present embodiment, the direction in which the left and right eyes of the observer are lined up is equal to the horizontal direction (first direction) in which the horizontal light guide unit 21 propagates the light beam, and the direction perpendicular to the rim 61 is vertical. The light guide unit 22 is equal to the vertical direction (second direction) in which the light beam propagates. With this configuration, the longitudinal direction of the mirrors of the vertical mirror group can be made equal to the direction in which the observer's eyes are lined up, so that the visibility of the vertical mirror group of the observer can be reduced.

According to the smart glasses of the present embodiment, it is possible to display a high-quality image with a wide angle of view to an observer wearing the smart glasses.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

For example, in the display devices of Examples 1 to 3, a display device that expands the luminous flux width in a two-dimensional direction has been described. However, the configuration of the horizontal mirror group or the vertical mirror group of the first embodiment may be applied to the mirror group of the display device for expanding the luminous flux width in the one-dimensional direction, or the horizontal propagation portion or the vertical propagation portion of the second embodiment may be applied. The configuration may be applied to the propagation portion of the display device that expands the luminous flux width in the one-dimensional direction. Further, the concept of the configuration of the mirror group of the third embodiment and the integration of the third embodiment may be applied to the propagation portion of the display device for expanding the luminous flux width in the one-dimensional direction.

1 Display device 2 Light guide plate (light guide element)
3 Incident optical system 4 Display element 5 Observer's eye 21 Horizontal light guide unit (first light guide unit)
22 Vertical light guide section (second light guide section)
211 Horizontal gene transfer section (first propagation section)
212 Horizontal mirror group (1st mirror group)
221 Vertical propagation section (second propagation section)
222 Vertical mirror group (second mirror group)
2113 Upper surface (first reflective surface)
2114 lower surface (first injection surface)
2211 Front (second injection surface)
2212 Back surface (second reflective surface)
2120 Horizontal take-out mirror (multiple mirrors)
2121 First reflection area (half mirror)
2122 Second reflection area (high reflection mirror)

Claims (10)

A display device including a light guide element and an incident optical system for incident light from the display element on the light guide element.
The light guide element guides the light from the incident optical system in a first direction and guides the light from the first light guide in a second direction intersecting the first direction. It has a second light guide and
At least one of the first light guide unit and the second light guide unit is a mirror that is arranged along the first direction or the second direction and reflects the light with the incident surface on which the light is incident. It has a group and a reflective surface facing the mirror group.
The mirror group each has a plurality of mirrors including a region that partially reflects the light.
The plurality of mirrors include a first mirror and a second mirror arranged between the first mirror and the incident surface .
A display device characterized in that the shortest distance between the reflecting surface and the first mirror is longer than the shortest distance between the reflecting surface and the second mirror. The first light guide unit is arranged along the first direction with the first incident surface as the incident surface, and the first mirror as the mirror group that guides the light to the second light guide unit. The display device according to claim 1, further comprising a group and a first reflecting surface as the reflecting surface facing the first mirror group. The second light guide unit has a second incident surface as the incident surface and a second mirror group as the mirror group that is arranged along the second direction and emits the light from the light guide element. The display device according to claim 1 or 2, wherein the display device has a second reflecting surface as the reflecting surface facing the second mirror group. A display device including a light guide element and an incident optical system for incident light from the display element on the light guide element.
The light guide element guides the light from the incident optical system in a first direction and guides the light from the first light guide in a second direction intersecting the first direction. It has a second light guide and
At least one of the first light guide unit and the second light guide unit is a mirror that is arranged along the first direction or the second direction and reflects the light with the incident surface on which the light is incident. Have a group and
The mirror group each has a plurality of mirrors including a region that partially reflects the light.
A display device characterized in that the distance between two mirrors adjacent to each other in the plurality of mirrors becomes longer as the distance from the incident surface increases. The first light guide unit is arranged along the first direction with the first incident surface as the incident surface, and the first mirror as the mirror group that guides the light to the second light guide unit. The display device according to claim 4, wherein the display device has a group. The second light guide unit has a second incident surface as the incident surface and a second mirror group as the mirror group that is arranged along the second direction and emits the light from the light guide element. The display device according to claim 4 or 5, wherein the display device has. The display device according to any one of claims 1 to 6, wherein the region that partially reflects the light is an amplitude division of the light. The display device according to any one of claims 1 to 6, wherein the region that partially reflects the light is polarized and divided. The display device according to any one of claims 1 to 8, wherein the plurality of mirrors are parallel to each other. A head-mounted display comprising the display device according to any one of claims 1 to 9 and a frame.

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